Merge branch 'rust-next' of https://github.com/Rust-for-Linux/linux.git

# Conflicts:
#	Makefile

198 files changed, 43691 insertions, 73 deletions

diff --git a/.gitignore b/.gitignore
index 265959544978..5da004814678 100644
--- a/.gitignore
+++ b/.gitignore
@@ -37,6 +37,8 @@
 *.o
 *.o.*
 *.patch
+*.rmeta
+*.rsi
 *.s
 *.so
 *.so.dbg
@@ -97,6 +99,7 @@ modules.order
 !.gitattributes
 !.gitignore
 !.mailmap
+!.rustfmt.toml
 
 #
 # Generated include files
@@ -162,3 +165,6 @@ x509.genkey
 
 # Documentation toolchain
 sphinx_*/
+
+# Rust analyzer configuration
+/rust-project.json
diff --git a/.rustfmt.toml b/.rustfmt.toml
new file mode 100644
index 000000000000..3de5cc497465
--- /dev/null
+++ b/.rustfmt.toml
@@ -0,0 +1,12 @@
+edition = "2021"
+newline_style = "Unix"
+
+# Unstable options that help catching some mistakes in formatting and that we may want to enable
+# when they become stable.
+#
+# They are kept here since they are useful to run from time to time.
+#format_code_in_doc_comments = true
+#reorder_impl_items = true
+#comment_width = 100
+#wrap_comments = true
+#normalize_comments = true
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index 5e89497ba314..dbe1aacc79d0 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -625,6 +625,16 @@ Examples::
 	%p4cc	Y10  little-endian (0x20303159)
 	%p4cc	NV12 big-endian (0xb231564e)
 
+Rust
+----
+
+::
+
+	%pA
+
+Only intended to be used from Rust code to format ``core::fmt::Arguments``.
+Do *not* use it from C.
+
 Thanks
 ======
 
diff --git a/Documentation/doc-guide/kernel-doc.rst b/Documentation/doc-guide/kernel-doc.rst
index 9c779bd7a751..1dcbd7332476 100644
--- a/Documentation/doc-guide/kernel-doc.rst
+++ b/Documentation/doc-guide/kernel-doc.rst
@@ -14,6 +14,9 @@ when it is embedded in source files.
    reasons. The kernel source contains tens of thousands of kernel-doc
    comments. Please stick to the style described here.
 
+.. note:: kernel-doc does not cover Rust code: please see
+   Documentation/rust/general-information.rst instead.
+
 The kernel-doc structure is extracted from the comments, and proper
 `Sphinx C Domain`_ function and type descriptions with anchors are
 generated from them. The descriptions are filtered for special kernel-doc
diff --git a/Documentation/index.rst b/Documentation/index.rst
index 67036a05b771..35d90903242a 100644
--- a/Documentation/index.rst
+++ b/Documentation/index.rst
@@ -82,6 +82,7 @@ merged much easier.
    maintainer/index
    fault-injection/index
    livepatch/index
+   rust/index
 
 
 Kernel API documentation
diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst
index ef19b9c13523..08f575e6236c 100644
--- a/Documentation/kbuild/kbuild.rst
+++ b/Documentation/kbuild/kbuild.rst
@@ -48,6 +48,10 @@ KCFLAGS
 -------
 Additional options to the C compiler (for built-in and modules).
 
+KRUSTFLAGS
+----------
+Additional options to the Rust compiler (for built-in and modules).
+
 CFLAGS_KERNEL
 -------------
 Additional options for $(CC) when used to compile
@@ -57,6 +61,15 @@ CFLAGS_MODULE
 -------------
 Additional module specific options to use for $(CC).
 
+RUSTFLAGS_KERNEL
+----------------
+Additional options for $(RUSTC) when used to compile
+code that is compiled as built-in.
+
+RUSTFLAGS_MODULE
+----------------
+Additional module specific options to use for $(RUSTC).
+
 LDFLAGS_MODULE
 --------------
 Additional options used for $(LD) when linking modules.
@@ -69,6 +82,10 @@ HOSTCXXFLAGS
 ------------
 Additional flags to be passed to $(HOSTCXX) when building host programs.
 
+HOSTRUSTFLAGS
+-------------
+Additional flags to be passed to $(HOSTRUSTC) when building host programs.
+
 HOSTLDFLAGS
 -----------
 Additional flags to be passed when linking host programs.
diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index 11a296e52d68..5ea1e72d89c8 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -29,8 +29,9 @@ This document describes the Linux kernel Makefiles.
 	   --- 4.1 Simple Host Program
 	   --- 4.2 Composite Host Programs
 	   --- 4.3 Using C++ for host programs
-	   --- 4.4 Controlling compiler options for host programs
-	   --- 4.5 When host programs are actually built
+	   --- 4.4 Using Rust for host programs
+	   --- 4.5 Controlling compiler options for host programs
+	   --- 4.6 When host programs are actually built
 
 	=== 5 Userspace Program support
 	   --- 5.1 Simple Userspace Program
@@ -835,7 +836,24 @@ Both possibilities are described in the following.
 		qconf-cxxobjs := qconf.o
 		qconf-objs    := check.o
 
-4.4 Controlling compiler options for host programs
+4.4 Using Rust for host programs
+--------------------------------
+
+	Kbuild offers support for host programs written in Rust. However,
+	since a Rust toolchain is not mandatory for kernel compilation,
+	it may only be used in scenarios where Rust is required to be
+	available (e.g. when  ``CONFIG_RUST`` is enabled).
+
+	Example::
+
+		hostprogs     := target
+		target-rust   := y
+
+	Kbuild will compile ``target`` using ``target.rs`` as the crate root,
+	located in the same directory as the ``Makefile``. The crate may
+	consist of several source files (see ``samples/rust/hostprogs``).
+
+4.5 Controlling compiler options for host programs
 --------------------------------------------------
 
 	When compiling host programs, it is possible to set specific flags.
@@ -867,7 +885,7 @@ Both possibilities are described in the following.
 	When linking qconf, it will be passed the extra option
 	"-L$(QTDIR)/lib".
 
-4.5 When host programs are actually built
+4.6 When host programs are actually built
 -----------------------------------------
 
 	Kbuild will only build host-programs when they are referenced
@@ -1181,6 +1199,17 @@ When kbuild executes, the following steps are followed (roughly):
 	The first example utilises the trick that a config option expands
 	to 'y' when selected.
 
+    KBUILD_RUSTFLAGS
+	$(RUSTC) compiler flags
+
+	Default value - see top level Makefile
+	Append or modify as required per architecture.
+
+	Often, the KBUILD_RUSTFLAGS variable depends on the configuration.
+
+	Note that target specification file generation (for ``--target``)
+	is handled in ``scripts/generate_rust_target.rs``.
+
     KBUILD_AFLAGS_KERNEL
 	Assembler options specific for built-in
 
@@ -1208,6 +1237,19 @@ When kbuild executes, the following steps are followed (roughly):
 	are used for $(CC).
 	From commandline CFLAGS_MODULE shall be used (see kbuild.rst).
 
+    KBUILD_RUSTFLAGS_KERNEL
+	$(RUSTC) options specific for built-in
+
+	$(KBUILD_RUSTFLAGS_KERNEL) contains extra Rust compiler flags used to
+	compile resident kernel code.
+
+    KBUILD_RUSTFLAGS_MODULE
+	Options for $(RUSTC) when building modules
+
+	$(KBUILD_RUSTFLAGS_MODULE) is used to add arch-specific options that
+	are used for $(RUSTC).
+	From commandline RUSTFLAGS_MODULE shall be used (see kbuild.rst).
+
     KBUILD_LDFLAGS_MODULE
 	Options for $(LD) when linking modules
 
diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index 19c286c23786..9a90197989dd 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -31,6 +31,8 @@ you probably needn't concern yourself with pcmciautils.
 ====================== ===============  ========================================
 GNU C                  5.1              gcc --version
 Clang/LLVM (optional)  11.0.0           clang --version
+Rust (optional)        1.62.0           rustc --version
+bindgen (optional)     0.56.0           bindgen --version
 GNU make               3.81             make --version
 bash                   4.2              bash --version
 binutils               2.23             ld -v
@@ -80,6 +82,29 @@ kernels. Older releases aren't guaranteed to work, and we may drop workarounds
 from the kernel that were used to support older versions. Please see additional
 docs on :ref:`Building Linux with Clang/LLVM <kbuild_llvm>`.
 
+Rust (optional)
+---------------
+
+A particular version of the Rust toolchain is required. Newer versions may or
+may not work because the kernel depends on some unstable Rust features, for
+the moment.
+
+Each Rust toolchain comes with several "components", some of which are required
+(like ``rustc``) and some that are optional. The ``rust-src`` component (which
+is optional) needs to be installed to build the kernel. Other components are
+useful for developing.
+
+Please see Documentation/rust/quick-start.rst for instructions on how to
+satisfy the build requirements of Rust support. In particular, the ``Makefile``
+target ``rustavailable`` is useful to check why the Rust toolchain may not
+be detected.
+
+bindgen (optional)
+------------------
+
+``bindgen`` is used to generate the Rust bindings to the C side of the kernel.
+It depends on ``libclang``.
+
 Make
 ----
 
@@ -348,6 +373,12 @@ Sphinx
 Please see :ref:`sphinx_install` in :ref:`Documentation/doc-guide/sphinx.rst <sphinxdoc>`
 for details about Sphinx requirements.
 
+rustdoc
+-------
+
+``rustdoc`` is used to generate the documentation for Rust code. Please see
+Documentation/rust/general-information.rst for more information.
+
 Getting updated software
 ========================
 
@@ -364,6 +395,16 @@ Clang/LLVM
 
 - :ref:`Getting LLVM <getting_llvm>`.
 
+Rust
+----
+
+- Documentation/rust/quick-start.rst.
+
+bindgen
+-------
+
+- Documentation/rust/quick-start.rst.
+
 Make
 ----
 
diff --git a/Documentation/rust/arch-support.rst b/Documentation/rust/arch-support.rst
new file mode 100644
index 000000000000..bcc92cae11d9
--- /dev/null
+++ b/Documentation/rust/arch-support.rst
@@ -0,0 +1,23 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Arch Support
+============
+
+Currently, the Rust compiler (``rustc``) uses LLVM for code generation,
+which limits the supported architectures that can be targeted. In addition,
+support for building the kernel with LLVM/Clang varies (please see
+Documentation/kbuild/llvm.rst). This support is needed for ``bindgen``
+which uses ``libclang``.
+
+Below is a general summary of architectures that currently work. Level of
+support corresponds to ``S`` values in the ``MAINTAINERS`` file.
+
+============  ================  ==============================================
+Architecture  Level of support  Constraints
+============  ================  ==============================================
+``arm``       Maintained        ``armv6`` and compatible only.
+``arm64``     Maintained        None.
+``powerpc``   Maintained        ``ppc64le`` only.
+``riscv``     Maintained        ``riscv64`` only.
+``x86``       Maintained        ``x86_64`` only.
+============  ================  ==============================================
diff --git a/Documentation/rust/coding-guidelines.rst b/Documentation/rust/coding-guidelines.rst
new file mode 100644
index 000000000000..aa8ed082613e
--- /dev/null
+++ b/Documentation/rust/coding-guidelines.rst
@@ -0,0 +1,216 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Coding Guidelines
+=================
+
+This document describes how to write Rust code in the kernel.
+
+
+Style & formatting
+------------------
+
+The code should be formatted using ``rustfmt``. In this way, a person
+contributing from time to time to the kernel does not need to learn and
+remember one more style guide. More importantly, reviewers and maintainers
+do not need to spend time pointing out style issues anymore, and thus
+less patch roundtrips may be needed to land a change.
+
+.. note:: Conventions on comments and documentation are not checked by
+  ``rustfmt``. Thus those are still needed to be taken care of.
+
+The default settings of ``rustfmt`` are used. This means the idiomatic Rust
+style is followed. For instance, 4 spaces are used for indentation rather
+than tabs.
+
+It is convenient to instruct editors/IDEs to format while typing,
+when saving or at commit time. However, if for some reason reformatting
+the entire kernel Rust sources is needed at some point, the following can be
+run::
+
+	make LLVM=1 rustfmt
+
+It is also possible to check if everything is formatted (printing a diff
+otherwise), for instance for a CI, with::
+
+	make LLVM=1 rustfmtcheck
+
+Like ``clang-format`` for the rest of the kernel, ``rustfmt`` works on
+individual files, and does not require a kernel configuration. Sometimes it may
+even work with broken code.
+
+
+Comments
+--------
+
+"Normal" comments (i.e. ``//``, rather than code documentation which starts
+with ``///`` or ``//!``) are written in Markdown the same way as documentation
+comments are, even though they will not be rendered. This improves consistency,
+simplifies the rules and allows to move content between the two kinds of
+comments more easily. For instance:
+
+.. code-block:: rust
+
+	// `object` is ready to be handled now.
+	f(object);
+
+Furthermore, just like documentation, comments are capitalized at the beginning
+of a sentence and ended with a period (even if it is a single sentence). This
+includes ``// SAFETY:``, ``// TODO:`` and other "tagged" comments, e.g.:
+
+.. code-block:: rust
+
+	// FIXME: The error should be handled properly.
+
+Comments should not be used for documentation purposes: comments are intended
+for implementation details, not users. This distinction is useful even if the
+reader of the source file is both an implementor and a user of an API. In fact,
+sometimes it is useful to use both comments and documentation at the same time.
+For instance, for a ``TODO`` list or to comment on the documentation itself.
+For the latter case, comments can be inserted in the middle; that is, closer to
+the line of documentation to be commented. For any other case, comments are
+written after the documentation, e.g.:
+
+.. code-block:: rust
+
+	/// Returns a new [`Foo`].
+	///
+	/// # Examples
+	///
+	// TODO: Find a better example.
+	/// ```
+	/// let foo = f(42);
+	/// ```
+	// FIXME: Use fallible approach.
+	pub fn f(x: i32) -> Foo {
+	    // ...
+	}
+
+One special kind of comments are the ``// SAFETY:`` comments. These must appear
+before every ``unsafe`` block, and they explain why the code inside the block is
+correct/sound, i.e. why it cannot trigger undefined behavior in any case, e.g.:
+
+.. code-block:: rust
+
+	// SAFETY: `p` is valid by the safety requirements.
+	unsafe { *p = 0; }
+
+``// SAFETY:`` comments are not to be confused with the ``# Safety`` sections
+in code documentation. ``# Safety`` sections specify the contract that callers
+(for functions) or implementors (for traits) need to abide by. ``// SAFETY:``
+comments show why a call (for functions) or implementation (for traits) actually
+respects the preconditions stated in a ``# Safety`` section or the language
+reference.
+
+
+Code documentation
+------------------
+
+Rust kernel code is not documented like C kernel code (i.e. via kernel-doc).
+Instead, the usual system for documenting Rust code is used: the ``rustdoc``
+tool, which uses Markdown (a lightweight markup language).
+
+To learn Markdown, there are many guides available out there. For instance,
+the one at:
+
+	https://commonmark.org/help/
+
+This is how a well-documented Rust function may look like:
+
+.. code-block:: rust
+
+	/// Returns the contained [`Some`] value, consuming the `self` value,
+	/// without checking that the value is not [`None`].
+	///
+	/// # Safety
+	///
+	/// Calling this method on [`None`] is *[undefined behavior]*.
+	///
+	/// [undefined behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
+	///
+	/// # Examples
+	///
+	/// ```
+	/// let x = Some("air");
+	/// assert_eq!(unsafe { x.unwrap_unchecked() }, "air");
+	/// ```
+	pub unsafe fn unwrap_unchecked(self) -> T {
+	    match self {
+	        Some(val) => val,
+
+	        // SAFETY: The safety contract must be upheld by the caller.
+	        None => unsafe { hint::unreachable_unchecked() },
+	    }
+	}
+
+This example showcases a few ``rustdoc`` features and some conventions followed
+in the kernel:
+
+  - The first paragraph must be a single sentence briefly describing what
+    the documented item does. Further explanations must go in extra paragraphs.
+
+  - Unsafe functions must document their safety preconditions under
+    a ``# Safety`` section.
+
+  - While not shown here, if a function may panic, the conditions under which
+    that happens must be described under a ``# Panics`` section.
+
+    Please note that panicking should be very rare and used only with a good
+    reason. In almost all cases, a fallible approach should be used, typically
+    returning a ``Result``.
+
+  - If providing examples of usage would help readers, they must be written in
+    a section called ``# Examples``.
+
+  - Rust items (functions, types, constants...) must be linked appropriately
+    (``rustdoc`` will create a link automatically).
+
+  - Any ``unsafe`` block must be preceded by a ``// SAFETY:`` comment
+    describing why the code inside is sound.
+
+    While sometimes the reason might look trivial and therefore unneeded,
+    writing these comments is not just a good way of documenting what has been
+    taken into account, but most importantly, it provides a way to know that
+    there are no *extra* implicit constraints.
+
+To learn more about how to write documentation for Rust and extra features,
+please take a look at the ``rustdoc`` book at:
+
+	https://doc.rust-lang.org/rustdoc/how-to-write-documentation.html
+
+
+Naming
+------
+
+Rust kernel code follows the usual Rust naming conventions:
+
+	https://rust-lang.github.io/api-guidelines/naming.html
+
+When existing C concepts (e.g. macros, functions, objects...) are wrapped into
+a Rust abstraction, a name as close as reasonably possible to the C side should
+be used in order to avoid confusion and to improve readability when switching
+back and forth between the C and Rust sides. For instance, macros such as
+``pr_info`` from C are named the same in the Rust side.
+
+Having said that, casing should be adjusted to follow the Rust naming
+conventions, and namespacing introduced by modules and types should not be
+repeated in the item names. For instance, when wrapping constants like:
+
+.. code-block:: c
+
+	#define GPIO_LINE_DIRECTION_IN	0
+	#define GPIO_LINE_DIRECTION_OUT	1
+
+The equivalent in Rust may look like (ignoring documentation):
+
+.. code-block:: rust
+
+	pub mod gpio {
+	    pub enum LineDirection {
+	        In = bindings::GPIO_LINE_DIRECTION_IN as _,
+	        Out = bindings::GPIO_LINE_DIRECTION_OUT as _,
+	    }
+	}
+
+That is, the equivalent of ``GPIO_LINE_DIRECTION_IN`` would be referred to as
+``gpio::LineDirection::In``. In particular, it should not be named
+``gpio::gpio_line_direction::GPIO_LINE_DIRECTION_IN``.
diff --git a/Documentation/rust/general-information.rst b/Documentation/rust/general-information.rst
new file mode 100644
index 000000000000..49029ee82e55
--- /dev/null
+++ b/Documentation/rust/general-information.rst
@@ -0,0 +1,79 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+General Information
+===================
+
+This document contains useful information to know when working with
+the Rust support in the kernel.
+
+
+Code documentation
+------------------
+
+Rust kernel code is documented using ``rustdoc``, its built-in documentation
+generator.
+
+The generated HTML docs include integrated search, linked items (e.g. types,
+functions, constants), source code, etc. They may be read at (TODO: link when
+in mainline and generated alongside the rest of the documentation):
+
+	http://kernel.org/
+
+The docs can also be easily generated and read locally. This is quite fast
+(same order as compiling the code itself) and no special tools or environment
+are needed. This has the added advantage that they will be tailored to
+the particular kernel configuration used. To generate them, use the ``rustdoc``
+target with the same invocation used for compilation, e.g.::
+
+	make LLVM=1 rustdoc
+
+To read the docs locally in your web browser, run e.g.::
+
+	xdg-open rust/doc/kernel/index.html
+
+To learn about how to write the documentation, please see coding-guidelines.rst.
+
+
+Extra lints
+-----------
+
+While ``rustc`` is a very helpful compiler, some extra lints and analyses are
+available via ``clippy``, a Rust linter. To enable it, pass ``CLIPPY=1`` to
+the same invocation used for compilation, e.g.::
+
+	make LLVM=1 CLIPPY=1
+
+Please note that Clippy may change code generation, thus it should not be
+enabled while building a production kernel.
+
+
+Abstractions vs. bindings
+-------------------------
+
+Abstractions are Rust code wrapping kernel functionality from the C side.
+
+In order to use functions and types from the C side, bindings are created.
+Bindings are the declarations for Rust of those functions and types from
+the C side.
+
+For instance, one may write a ``Mutex`` abstraction in Rust which wraps
+a ``struct mutex`` from the C side and calls its functions through the bindings.
+
+Abstractions are not available for all the kernel internal APIs and concepts,
+but it is intended that coverage is expanded as time goes on. "Leaf" modules
+(e.g. drivers) should not use the C bindings directly. Instead, subsystems
+should provide as-safe-as-possible abstractions as needed.
+
+
+Conditional compilation
+-----------------------
+
+Rust code has access to conditional compilation based on the kernel
+configuration:
+
+.. code-block:: rust
+
+	#[cfg(CONFIG_X)]       // Enabled               (`y` or `m`)
+	#[cfg(CONFIG_X="y")]   // Enabled as a built-in (`y`)
+	#[cfg(CONFIG_X="m")]   // Enabled as a module   (`m`)
+	#[cfg(not(CONFIG_X))]  // Disabled
diff --git a/Documentation/rust/index.rst b/Documentation/rust/index.rst
new file mode 100644
index 000000000000..4ae8c66b94fa
--- /dev/null
+++ b/Documentation/rust/index.rst
@@ -0,0 +1,22 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Rust
+====
+
+Documentation related to Rust within the kernel. To start using Rust
+in the kernel, please read the quick-start.rst guide.
+
+.. toctree::
+    :maxdepth: 1
+
+    quick-start
+    general-information
+    coding-guidelines
+    arch-support
+
+.. only::  subproject and html
+
+   Indices
+   =======
+
+   * :ref:`genindex`
diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
new file mode 100644
index 000000000000..13b7744b1e27
--- /dev/null
+++ b/Documentation/rust/quick-start.rst
@@ -0,0 +1,232 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Quick Start
+===========
+
+This document describes how to get started with kernel development in Rust.
+
+
+Requirements: Building
+----------------------
+
+This section explains how to fetch the tools needed for building.
+
+Some of these requirements might be available from Linux distributions
+under names like ``rustc``, ``rust-src``, ``rust-bindgen``, etc. However,
+at the time of writing, they are likely not to be recent enough unless
+the distribution tracks the latest releases.
+
+To easily check whether the requirements are met, the following target
+can be used::
+
+	make LLVM=1 rustavailable
+
+This triggers the same logic used by Kconfig to determine whether
+``RUST_IS_AVAILABLE`` should be enabled; but it also explains why not
+if that is the case.
+
+
+rustc
+*****
+
+A particular version of the Rust compiler is required. Newer versions may or
+may not work because, for the moment, the kernel depends on some unstable
+Rust features.
+
+If ``rustup`` is being used, enter the checked out source code directory
+and run::
+
+	rustup override set $(scripts/min-tool-version.sh rustc)
+
+Otherwise, fetch a standalone installer or install ``rustup`` from:
+
+	https://www.rust-lang.org
+
+
+Rust standard library source
+****************************
+
+The Rust standard library source is required because the build system will
+cross-compile ``core`` and ``alloc``.
+
+If ``rustup`` is being used, run::
+
+	rustup component add rust-src
+
+The components are installed per toolchain, thus upgrading the Rust compiler
+version later on requires re-adding the component.
+
+Otherwise, if a standalone installer is used, the Rust repository may be cloned
+into the installation folder of the toolchain::
+
+	git clone --recurse-submodules \
+		--branch $(scripts/min-tool-version.sh rustc) \
+		https://github.com/rust-lang/rust \
+		$(rustc --print sysroot)/lib/rustlib/src/rust
+
+In this case, upgrading the Rust compiler version later on requires manually
+updating this clone.
+
+
+libclang
+********
+
+``libclang`` (part of LLVM) is used by ``bindgen`` to understand the C code
+in the kernel, which means LLVM needs to be installed; like when the kernel
+is compiled with ``CC=clang`` or ``LLVM=1``.
+
+Linux distributions are likely to have a suitable one available, so it is
+best to check that first.
+
+There are also some binaries for several systems and architectures uploaded at:
+
+	https://releases.llvm.org/download.html
+
+Otherwise, building LLVM takes quite a while, but it is not a complex process:
+
+	https://llvm.org/docs/GettingStarted.html#getting-the-source-code-and-building-llvm
+
+Please see Documentation/kbuild/llvm.rst for more information and further ways
+to fetch pre-built releases and distribution packages.
+
+
+bindgen
+*******
+
+The bindings to the C side of the kernel are generated at build time using
+the ``bindgen`` tool. A particular version is required.
+
+Install it via (note that this will download and build the tool from source)::
+
+	cargo install --locked --version $(scripts/min-tool-version.sh bindgen) bindgen
+
+
+Requirements: Developing
+------------------------
+
+This section explains how to fetch the tools needed for developing. That is,
+they are not needed when just building the kernel.
+
+
+rustfmt
+*******
+
+The ``rustfmt`` tool is used to automatically format all the Rust kernel code,
+including the generated C bindings (for details, please see
+coding-guidelines.rst).
+
+If ``rustup`` is being used, its ``default`` profile already installs the tool,
+thus nothing needs to be done. If another profile is being used, the component
+can be installed manually::
+
+	rustup component add rustfmt
+
+The standalone installers also come with ``rustfmt``.
+
+
+clippy
+******
+
+``clippy`` is a Rust linter. Running it provides extra warnings for Rust code.
+It can be run by passing ``CLIPPY=1`` to ``make`` (for details, please see
+general-information.rst).
+
+If ``rustup`` is being used, its ``default`` profile already installs the tool,
+thus nothing needs to be done. If another profile is being used, the component
+can be installed manually::
+
+	rustup component add clippy
+
+The standalone installers also come with ``clippy``.
+
+
+cargo
+*****
+
+``cargo`` is the Rust native build system. It is currently required to run
+the tests since it is used to build a custom standard library that contains
+the facilities provided by the custom ``alloc`` in the kernel. The tests can
+be run using the ``rusttest`` Make target.
+
+If ``rustup`` is being used, all the profiles already install the tool,
+thus nothing needs to be done.
+
+The standalone installers also come with ``cargo``.
+
+
+rustdoc
+*******
+
+``rustdoc`` is the documentation tool for Rust. It generates pretty HTML
+documentation for Rust code (for details, please see
+general-information.rst).
+
+``rustdoc`` is also used to test the examples provided in documented Rust code
+(called doctests or documentation tests). The ``rusttest`` Make target uses
+this feature.
+
+If ``rustup`` is being used, all the profiles already install the tool,
+thus nothing needs to be done.
+
+The standalone installers also come with ``rustdoc``.
+
+
+rust-analyzer
+*************
+
+The `rust-analyzer <https://rust-analyzer.github.io/>`_ language server can
+be used with many editors to enable syntax highlighting, completion, go to
+definition, and other features.
+
+``rust-analyzer`` needs a configuration file, ``rust-project.json``, which
+can be generated by the ``rust-analyzer`` Make target.
+
+
+Configuration
+-------------
+
+``Rust support`` (``CONFIG_RUST``) needs to be enabled in the ``General setup``
+menu. The option is only shown if a suitable Rust toolchain is found (see
+above), as long as the other requirements are met. In turn, this will make
+visible the rest of options that depend on Rust.
+
+Afterwards, go to::
+
+	Kernel hacking
+	    -> Sample kernel code
+	        -> Rust samples
+
+And enable some sample modules either as built-in or as loadable.
+
+
+Building
+--------
+
+Building a kernel with a complete LLVM toolchain is the best supported setup
+at the moment. That is::
+
+	make LLVM=1
+
+For architectures that do not support a full LLVM toolchain, use::
+
+	make CC=clang
+
+Using GCC also works for some configurations, but it is very experimental at
+the moment.
+
+
+Hacking
+-------
+
+To dive deeper, take a look at the source code of the samples
+at ``samples/rust/``, the Rust support code under ``rust/`` and
+the ``Rust hacking`` menu under ``Kernel hacking``.
+
+If GDB/Binutils is used and Rust symbols are not getting demangled, the reason
+is the toolchain does not support Rust's new v0 mangling scheme yet.
+There are a few ways out:
+
+  - Install a newer release (GDB >= 10.2, Binutils >= 2.36).
+
+  - Some versions of GDB (e.g. vanilla GDB 10.1) are able to use
+    the pre-demangled names embedded in the debug info (``CONFIG_DEBUG_INFO``).
diff --git a/MAINTAINERS b/MAINTAINERS
index b8696cc2211e..c5ea1aa99b96 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17727,6 +17727,21 @@ L:	linux-rdma@vger.kernel.org
 S:	Maintained
 F:	drivers/infiniband/ulp/rtrs/
 
+RUST
+M:	Miguel Ojeda <ojeda@kernel.org>
+M:	Alex Gaynor <alex.gaynor@gmail.com>
+M:	Wedson Almeida Filho <wedsonaf@google.com>
+L:	rust-for-linux@vger.kernel.org
+S:	Supported
+W:	https://github.com/Rust-for-Linux/linux
+B:	https://github.com/Rust-for-Linux/linux/issues
+T:	git https://github.com/Rust-for-Linux/linux.git rust-next
+F:	Documentation/rust/
+F:	rust/
+F:	samples/rust/
+F:	scripts/*rust*
+K:	\b(?i:rust)\b
+
 RXRPC SOCKETS (AF_RXRPC)
 M:	David Howells <dhowells@redhat.com>
 M:	Marc Dionne <marc.dionne@auristor.com>
diff --git a/Makefile b/Makefile
index 60a7e3e8b478..36d69eb967e4 100644
--- a/Makefile
+++ b/Makefile
@@ -120,6 +120,15 @@ endif
 
 export KBUILD_CHECKSRC
 
+# Enable "clippy" (a linter) as part of the Rust compilation.
+#
+# Use 'make CLIPPY=1' to enable it.
+ifeq ("$(origin CLIPPY)", "command line")
+  KBUILD_CLIPPY := $(CLIPPY)
+endif
+
+export KBUILD_CLIPPY
+
 # Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the
 # directory of external module to build. Setting M= takes precedence.
 ifeq ("$(origin M)", "command line")
@@ -270,14 +279,14 @@ no-dot-config-targets := $(clean-targets) \
 			 cscope gtags TAGS tags help% %docs check% coccicheck \
 			 $(version_h) headers headers_% archheaders archscripts \
 			 %asm-generic kernelversion %src-pkg dt_binding_check \
-			 outputmakefile
+			 outputmakefile rustavailable rustfmt rustfmtcheck
 # Installation targets should not require compiler. Unfortunately, vdso_install
 # is an exception where build artifacts may be updated. This must be fixed.
 no-compiler-targets := $(no-dot-config-targets) install dtbs_install \
 			headers_install modules_install kernelrelease image_name
 no-sync-config-targets := $(no-dot-config-targets) %install kernelrelease \
 			  image_name
-single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.s %.symtypes %/
+single-targets := %.a %.i %.rsi %.ko %.lds %.ll %.lst %.mod %.o %.s %.symtypes %/
 
 config-build	:=
 mixed-build	:=
@@ -439,6 +448,7 @@ else
 HOSTCC	= gcc
 HOSTCXX	= g++
 endif
+HOSTRUSTC = rustc
 HOSTPKG_CONFIG	= pkg-config
 
 KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
@@ -447,8 +457,26 @@ KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
 KBUILD_USERCFLAGS  := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS)
 KBUILD_USERLDFLAGS := $(USERLDFLAGS)
 
+# These flags apply to all Rust code in the tree, including the kernel and
+# host programs.
+export rust_common_flags := --edition=2021 \
+			    -Zbinary_dep_depinfo=y \
+			    -Dunsafe_op_in_unsafe_fn -Drust_2018_idioms \
+			    -Dunreachable_pub -Dnon_ascii_idents \
+			    -Wmissing_docs \
+			    -Drustdoc::missing_crate_level_docs \
+			    -Dclippy::correctness -Dclippy::style \
+			    -Dclippy::suspicious -Dclippy::complexity \
+			    -Dclippy::perf \
+			    -Dclippy::let_unit_value -Dclippy::mut_mut \
+			    -Dclippy::needless_bitwise_bool \
+			    -Dclippy::needless_continue \
+			    -Wclippy::dbg_macro
+
 KBUILD_HOSTCFLAGS   := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
 KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
+KBUILD_HOSTRUSTFLAGS := $(rust_common_flags) -O -Cstrip=debuginfo \
+			-Zallow-features= $(HOSTRUSTFLAGS)
 KBUILD_HOSTLDFLAGS  := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
 KBUILD_HOSTLDLIBS   := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
 
@@ -473,6 +501,12 @@ OBJDUMP		= $(CROSS_COMPILE)objdump
 READELF		= $(CROSS_COMPILE)readelf
 STRIP		= $(CROSS_COMPILE)strip
 endif
+RUSTC		= rustc
+RUSTDOC		= rustdoc
+RUSTFMT		= rustfmt
+CLIPPY_DRIVER	= clippy-driver
+BINDGEN		= bindgen
+CARGO		= cargo
 PAHOLE		= pahole
 RESOLVE_BTFIDS	= $(objtree)/tools/bpf/resolve_btfids/resolve_btfids
 LEX		= flex
@@ -498,9 +532,11 @@ CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
 		  -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF)
 NOSTDINC_FLAGS :=
 CFLAGS_MODULE   =
+RUSTFLAGS_MODULE =
 AFLAGS_MODULE   =
 LDFLAGS_MODULE  =
 CFLAGS_KERNEL	=
+RUSTFLAGS_KERNEL =
 AFLAGS_KERNEL	=
 LDFLAGS_vmlinux =
 
@@ -529,15 +565,42 @@ KBUILD_CFLAGS   := -Wall -Wundef -Werror=strict-prototypes -Wno-trigraphs \
 		   -Werror=return-type -Wno-format-security \
 		   -std=gnu11
 KBUILD_CPPFLAGS := -D__KERNEL__
+KBUILD_RUSTFLAGS := $(rust_common_flags) \
+		    --target=$(objtree)/rust/target.json \
+		    -Cpanic=abort -Cembed-bitcode=n -Clto=n \
+		    -Cforce-unwind-tables=n -Ccodegen-units=1 \
+		    -Csymbol-mangling-version=v0 \
+		    -Crelocation-model=static \
+		    -Zfunction-sections=n \
+		    -Dclippy::float_arithmetic
+
 KBUILD_AFLAGS_KERNEL :=
 KBUILD_CFLAGS_KERNEL :=
+KBUILD_RUSTFLAGS_KERNEL :=
 KBUILD_AFLAGS_MODULE  := -DMODULE
 KBUILD_CFLAGS_MODULE  := -DMODULE
+KBUILD_RUSTFLAGS_MODULE := --cfg MODULE
 KBUILD_LDFLAGS_MODULE :=
 KBUILD_LDFLAGS :=
 CLANG_FLAGS :=
 
+ifeq ($(KBUILD_CLIPPY),1)
+	RUSTC_OR_CLIPPY_QUIET := CLIPPY
+	RUSTC_OR_CLIPPY = $(CLIPPY_DRIVER)
+else
+	RUSTC_OR_CLIPPY_QUIET := RUSTC
+	RUSTC_OR_CLIPPY = $(RUSTC)
+endif
+
+ifdef RUST_LIB_SRC
+	export RUST_LIB_SRC
+endif
+
+export RUSTC_BOOTSTRAP := 1
+
 export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC HOSTPKG_CONFIG
+export RUSTC RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN CARGO
+export HOSTRUSTC KBUILD_HOSTRUSTFLAGS
 export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
 export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
@@ -546,9 +609,10 @@ export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS
 
 export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
 export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
+export KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE
 export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
-export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_LDFLAGS_MODULE
-export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL
+export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_RUSTFLAGS_MODULE KBUILD_LDFLAGS_MODULE
+export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL KBUILD_RUSTFLAGS_KERNEL
 export PAHOLE_FLAGS
 
 # Files to ignore in find ... statements
@@ -729,7 +793,7 @@ $(KCONFIG_CONFIG):
 #
 # Do not use $(call cmd,...) here. That would suppress prompts from syncconfig,
 # so you cannot notice that Kconfig is waiting for the user input.
-%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h: $(KCONFIG_CONFIG)
+%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h %/generated/rustc_cfg: $(KCONFIG_CONFIG)
 	$(Q)$(kecho) "  SYNC    $@"
 	$(Q)$(MAKE) -f $(srctree)/Makefile syncconfig
 else # !may-sync-config
@@ -758,10 +822,17 @@ KBUILD_CFLAGS	+= $(call cc-disable-warning, address-of-packed-member)
 
 ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
 KBUILD_CFLAGS += -O2
+KBUILD_RUSTFLAGS += -Copt-level=2
 else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
 KBUILD_CFLAGS += -Os
+KBUILD_RUSTFLAGS += -Copt-level=s
 endif
 
+# Always set `debug-assertions` and `overflow-checks` because their default
+# depends on `opt-level` and `debug-assertions`, respectively.
+KBUILD_RUSTFLAGS += -Cdebug-assertions=$(if $(CONFIG_RUST_DEBUG_ASSERTIONS),y,n)
+KBUILD_RUSTFLAGS += -Coverflow-checks=$(if $(CONFIG_RUST_OVERFLOW_CHECKS),y,n)
+
 # Tell gcc to never replace conditional load with a non-conditional one
 ifdef CONFIG_CC_IS_GCC
 # gcc-10 renamed --param=allow-store-data-races=0 to
@@ -792,6 +863,9 @@ KBUILD_CFLAGS-$(CONFIG_WERROR) += -Werror
 KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds
 KBUILD_CFLAGS += $(KBUILD_CFLAGS-y) $(CONFIG_CC_IMPLICIT_FALLTHROUGH)
 
+KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings
+KBUILD_RUSTFLAGS += $(KBUILD_RUSTFLAGS-y)
+
 ifdef CONFIG_CC_IS_CLANG
 KBUILD_CPPFLAGS += -Qunused-arguments
 # The kernel builds with '-std=gnu11' so use of GNU extensions is acceptable.
@@ -812,12 +886,15 @@ KBUILD_CFLAGS += $(call cc-disable-warning, dangling-pointer)
 
 ifdef CONFIG_FRAME_POINTER
 KBUILD_CFLAGS	+= -fno-omit-frame-pointer -fno-optimize-sibling-calls
+KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y
 else
 # Some targets (ARM with Thumb2, for example), can't be built with frame
 # pointers.  For those, we don't have FUNCTION_TRACER automatically
 # select FRAME_POINTER.  However, FUNCTION_TRACER adds -pg, and this is
 # incompatible with -fomit-frame-pointer with current GCC, so we don't use
 # -fomit-frame-pointer with FUNCTION_TRACER.
+# In the Rust target specification, "frame-pointer" is set explicitly
+# to "may-omit".
 ifndef CONFIG_FUNCTION_TRACER
 KBUILD_CFLAGS	+= -fomit-frame-pointer
 endif
@@ -882,8 +959,10 @@ ifdef CONFIG_DEBUG_SECTION_MISMATCH
 KBUILD_CFLAGS += -fno-inline-functions-called-once
 endif
 
+# `rustc`'s `-Zfunction-sections` applies to data too (as of 1.59.0).
 ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
 KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections
+KBUILD_RUSTFLAGS_KERNEL += -Zfunction-sections=y
 LDFLAGS_vmlinux += --gc-sections
 endif
 
@@ -1026,10 +1105,11 @@ include $(addprefix $(srctree)/, $(include-y))
 # Do not add $(call cc-option,...) below this line. When you build the kernel
 # from the clean source tree, the GCC plugins do not exist at this point.
 
-# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
+# Add user supplied CPPFLAGS, AFLAGS, CFLAGS and RUSTFLAGS as the last assignments
 KBUILD_CPPFLAGS += $(KCPPFLAGS)
 KBUILD_AFLAGS   += $(KAFLAGS)
 KBUILD_CFLAGS   += $(KCFLAGS)
+KBUILD_RUSTFLAGS += $(KRUSTFLAGS)
 
 KBUILD_LDFLAGS_MODULE += --build-id=sha1
 LDFLAGS_vmlinux += --build-id=sha1
@@ -1099,6 +1179,7 @@ ifeq ($(KBUILD_EXTMOD),)
 core-y			+= kernel/ certs/ mm/ fs/ ipc/ security/ crypto/
 core-$(CONFIG_BLOCK)	+= block/
 core-$(CONFIG_IO_URING)	+= io_uring/
+core-$(CONFIG_RUST)	+= rust/
 
 vmlinux-dirs	:= $(patsubst %/,%,$(filter %/, \
 		     $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
@@ -1203,6 +1284,10 @@ prepare0: archprepare
 
 # All the preparing..
 prepare: prepare0
+ifdef CONFIG_RUST
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust-is-available.sh -v
+	$(Q)$(MAKE) $(build)=rust
+endif
 
 PHONY += remove-stale-files
 remove-stale-files:
@@ -1497,7 +1582,7 @@ endif # CONFIG_MODULES
 # Directories & files removed with 'make clean'
 CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \
 	       modules.builtin modules.builtin.modinfo modules.nsdeps \
-	       compile_commands.json .thinlto-cache
+	       compile_commands.json .thinlto-cache rust/test rust/doc
 
 # Directories & files removed with 'make mrproper'
 MRPROPER_FILES += include/config include/generated          \
@@ -1508,7 +1593,8 @@ MRPROPER_FILES += include/config include/generated          \
 		  certs/signing_key.pem \
 		  certs/x509.genkey \
 		  vmlinux-gdb.py \
-		  *.spec
+		  *.spec \
+		  rust/target.json rust/libmacros.so
 
 # clean - Delete most, but leave enough to build external modules
 #
@@ -1533,6 +1619,9 @@ $(mrproper-dirs):
 
 mrproper: clean $(mrproper-dirs)
 	$(call cmd,rmfiles)
+	@find . $(RCS_FIND_IGNORE) \
+		\( -name '*.rmeta' \) \
+		-type f -print | xargs rm -f
 
 # distclean
 #
@@ -1620,6 +1709,24 @@ help:
 	@echo  '  kselftest-merge   - Merge all the config dependencies of'
 	@echo  '		      kselftest to existing .config.'
 	@echo  ''
+	@echo  'Rust targets:'
+	@echo  '  rustavailable   - Checks whether the Rust toolchain is'
+	@echo  '		    available and, if not, explains why.'
+	@echo  '  rustfmt	  - Reformat all the Rust code in the kernel'
+	@echo  '  rustfmtcheck	  - Checks if all the Rust code in the kernel'
+	@echo  '		    is formatted, printing a diff otherwise.'
+	@echo  '  rustdoc	  - Generate Rust documentation'
+	@echo  '		    (requires kernel .config)'
+	@echo  '  rusttest        - Runs the Rust tests'
+	@echo  '                    (requires kernel .config; downloads external repos)'
+	@echo  '  rust-analyzer	  - Generate rust-project.json rust-analyzer support file'
+	@echo  '		    (requires kernel .config)'
+	@echo  '  dir/file.[os]   - Build specified target only'
+	@echo  '  dir/file.rsi    - Build macro expanded source, similar to C preprocessing.'
+	@echo  '                    Run with RUSTFMT=n to skip reformatting if needed.'
+	@echo  '                    The output is not intended to be compilable.'
+	@echo  '  dir/file.ll     - Build the LLVM assembly file'
+	@echo  ''
 	@$(if $(dtstree), \
 		echo 'Devicetree:'; \
 		echo '* dtbs             - Build device tree blobs for enabled boards'; \
@@ -1692,6 +1799,52 @@ PHONY += $(DOC_TARGETS)
 $(DOC_TARGETS):
 	$(Q)$(MAKE) $(build)=Documentation $@
 
+
+# Rust targets
+# ---------------------------------------------------------------------------
+
+# "Is Rust available?" target
+PHONY += rustavailable
+rustavailable:
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust-is-available.sh -v && echo "Rust is available!"
+
+# Documentation target
+#
+# Using the singular to avoid running afoul of `no-dot-config-targets`.
+PHONY += rustdoc
+rustdoc: prepare
+	$(Q)$(MAKE) $(build)=rust $@
+
+# Testing target
+PHONY += rusttest
+rusttest: prepare
+	$(Q)$(MAKE) $(build)=rust $@
+
+# Formatting targets
+PHONY += rustfmt rustfmtcheck
+
+# We skip `rust/alloc` since we want to minimize the diff w.r.t. upstream.
+#
+# We match using absolute paths since `find` does not resolve them
+# when matching, which is a problem when e.g. `srctree` is `..`.
+# We `grep` afterwards in order to remove the directory entry itself.
+rustfmt:
+	$(Q)find $(abs_srctree) -type f -name '*.rs' \
+		-o -path $(abs_srctree)/rust/alloc -prune \
+		-o -path $(abs_objtree)/rust/test -prune \
+		| grep -Fv $(abs_srctree)/rust/alloc \
+		| grep -Fv $(abs_objtree)/rust/test \
+		| grep -Fv generated \
+		| xargs $(RUSTFMT) $(rustfmt_flags)
+
+rustfmtcheck: rustfmt_flags = --check
+rustfmtcheck: rustfmt
+
+# IDE support targets
+PHONY += rust-analyzer
+rust-analyzer:
+	$(Q)$(MAKE) $(build)=rust $@
+
 # Misc
 # ---------------------------------------------------------------------------
 
@@ -1859,7 +2012,7 @@ $(clean-dirs):
 clean: $(clean-dirs)
 	$(call cmd,rmfiles)
 	@find $(or $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
-		\( -name '*.[aios]' -o -name '*.ko' -o -name '.*.cmd' \
+		\( -name '*.[aios]' -o -name '*.rsi' -o -name '*.ko' -o -name '.*.cmd' \
 		-o -name '*.ko.*' \
 		-o -name '*.dtb' -o -name '*.dtbo' -o -name '*.dtb.S' -o -name '*.dt.yaml' \
 		-o -name '*.dwo' -o -name '*.lst' \
diff --git a/arch/Kconfig b/arch/Kconfig
index f330410da63a..f63e5b7f40f5 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -356,6 +356,12 @@ config HAVE_RSEQ
 	  This symbol should be selected by an architecture if it
 	  supports an implementation of restartable sequences.
 
+config HAVE_RUST
+	bool
+	help
+	  This symbol should be selected by an architecture if it
+	  supports Rust.
+
 config HAVE_FUNCTION_ARG_ACCESS_API
 	bool
 	help
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 87badeae3181..c7fb8ef3b12d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -116,6 +116,7 @@ config ARM
 	select MMU_GATHER_RCU_TABLE_FREE if SMP && ARM_LPAE
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RSEQ
+	select HAVE_RUST if CPU_32v6 || CPU_32v6K
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UID16
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 6bb50124a7e9..d2eb39b79b18 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -205,6 +205,7 @@ config ARM64
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select MMU_GATHER_RCU_TABLE_FREE
 	select HAVE_RSEQ
+	select HAVE_RUST
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_KPROBES
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c3bb865f1f73..cf9a33d6c430 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -245,6 +245,7 @@ config PPC
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
+	select HAVE_RUST			if PPC64 && CPU_LITTLE_ENDIAN
 	select HAVE_SETUP_PER_CPU_AREA		if PPC64
 	select HAVE_SOFTIRQ_ON_OWN_STACK
 	select HAVE_STACKPROTECTOR		if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5c52a82e83a8..205c1e2f539c 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -104,6 +104,7 @@ config RISCV
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_RUST if 64BIT
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 81029d40a672..24ebe042406e 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -26,6 +26,8 @@ ifeq ($(CONFIG_ARCH_RV64I),y)
 	KBUILD_CFLAGS += -mabi=lp64
 	KBUILD_AFLAGS += -mabi=lp64
 
+	KBUILD_RUSTFLAGS += -Ctarget-cpu=generic-rv64
+
 	KBUILD_LDFLAGS += -melf64lriscv
 else
 	BITS := 32
@@ -33,6 +35,9 @@ else
 
 	KBUILD_CFLAGS += -mabi=ilp32
 	KBUILD_AFLAGS += -mabi=ilp32
+
+	KBUILD_RUSTFLAGS += -Ctarget-cpu=generic-rv32
+
 	KBUILD_LDFLAGS += -melf32lriscv
 endif
 
diff --git a/arch/um/Kconfig b/arch/um/Kconfig
index 78de31ac1da7..61f84b2b165e 100644
--- a/arch/um/Kconfig
+++ b/arch/um/Kconfig
@@ -27,6 +27,7 @@ config UML
 	select TRACE_IRQFLAGS_SUPPORT
 	select TTY # Needed for line.c
 	select HAVE_ARCH_VMAP_STACK
+	select HAVE_RUST			if X86_64
 
 config MMU
 	bool
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index cca4c0ac39cc..74572c65d97f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -258,6 +258,7 @@ config X86
 	select HAVE_STATIC_CALL_INLINE		if HAVE_OBJTOOL
 	select HAVE_PREEMPT_DYNAMIC_CALL
 	select HAVE_RSEQ
+	select HAVE_RUST			if X86_64
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_UACCESS_VALIDATION		if HAVE_OBJTOOL
 	select HAVE_UNSTABLE_SCHED_CLOCK
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 7854685c5f25..bab595003f07 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -68,6 +68,7 @@ export BITS
 #    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53383
 #
 KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow -mno-avx
+KBUILD_RUSTFLAGS += -Ctarget-feature=-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-avx,-avx2
 
 ifeq ($(CONFIG_X86_KERNEL_IBT),y)
 #
@@ -155,8 +156,17 @@ else
         cflags-$(CONFIG_GENERIC_CPU)	+= -mtune=generic
         KBUILD_CFLAGS += $(cflags-y)
 
+        rustflags-$(CONFIG_MK8)		+= -Ctarget-cpu=k8
+        rustflags-$(CONFIG_MPSC)	+= -Ctarget-cpu=nocona
+        rustflags-$(CONFIG_MCORE2)	+= -Ctarget-cpu=core2
+        rustflags-$(CONFIG_MATOM)	+= -Ctarget-cpu=atom
+        rustflags-$(CONFIG_GENERIC_CPU)	+= -Ztune-cpu=generic
+        KBUILD_RUSTFLAGS += $(rustflags-y)
+
         KBUILD_CFLAGS += -mno-red-zone
         KBUILD_CFLAGS += -mcmodel=kernel
+        KBUILD_RUSTFLAGS += -Cno-redzone=y
+        KBUILD_RUSTFLAGS += -Ccode-model=kernel
 endif
 
 #
diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig
index 07aa8ae0a058..37f7080807c5 100644
--- a/drivers/android/Kconfig
+++ b/drivers/android/Kconfig
@@ -13,6 +13,12 @@ config ANDROID_BINDER_IPC
 	  Android process, using Binder to identify, invoke and pass arguments
 	  between said processes.
 
+config ANDROID_BINDER_IPC_RUST
+	bool "Android Binder IPC Driver in Rust"
+	depends on MMU && RUST
+	help
+	  Implementation of the Binder IPC in Rust.
+
 config ANDROID_BINDERFS
 	bool "Android Binderfs filesystem"
 	depends on ANDROID_BINDER_IPC
diff --git a/drivers/android/Makefile b/drivers/android/Makefile
index c9d3d0c99c25..c428f2ce2f05 100644
--- a/drivers/android/Makefile
+++ b/drivers/android/Makefile
@@ -4,3 +4,5 @@ ccflags-y += -I$(src)			# needed for trace events
 obj-$(CONFIG_ANDROID_BINDERFS)		+= binderfs.o
 obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder.o binder_alloc.o
 obj-$(CONFIG_ANDROID_BINDER_IPC_SELFTEST) += binder_alloc_selftest.o
+
+obj-$(CONFIG_ANDROID_BINDER_IPC_RUST) += rust_binder.o
diff --git a/drivers/android/allocation.rs b/drivers/android/allocation.rs
new file mode 100644
index 000000000000..3ed7b649eeb7
--- /dev/null
+++ b/drivers/android/allocation.rs
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::mem::{replace, size_of, MaybeUninit};
+use kernel::{
+    bindings, linked_list::List, pages::Pages, prelude::*, sync::Ref, user_ptr::UserSlicePtrReader,
+};
+
+use crate::{
+    defs::*,
+    node::NodeRef,
+    process::{AllocationInfo, Process},
+    thread::{BinderError, BinderResult},
+    transaction::FileInfo,
+};
+
+pub(crate) struct Allocation<'a> {
+    pub(crate) offset: usize,
+    size: usize,
+    pub(crate) ptr: usize,
+    pages: Ref<[Pages<0>]>,
+    pub(crate) process: &'a Process,
+    allocation_info: Option<AllocationInfo>,
+    free_on_drop: bool,
+    file_list: List<Box<FileInfo>>,
+}
+
+impl<'a> Allocation<'a> {
+    pub(crate) fn new(
+        process: &'a Process,
+        offset: usize,
+        size: usize,
+        ptr: usize,
+        pages: Ref<[Pages<0>]>,
+    ) -> Self {
+        Self {
+            process,
+            offset,
+            size,
+            ptr,
+            pages,
+            allocation_info: None,
+            free_on_drop: true,
+            file_list: List::new(),
+        }
+    }
+
+    pub(crate) fn take_file_list(&mut self) -> List<Box<FileInfo>> {
+        replace(&mut self.file_list, List::new())
+    }
+
+    pub(crate) fn add_file_info(&mut self, file: Box<FileInfo>) {
+        self.file_list.push_back(file);
+    }
+
+    fn iterate<T>(&self, mut offset: usize, mut size: usize, mut cb: T) -> Result
+    where
+        T: FnMut(&Pages<0>, usize, usize) -> Result,
+    {
+        // Check that the request is within the buffer.
+        if offset.checked_add(size).ok_or(EINVAL)? > self.size {
+            return Err(EINVAL);
+        }
+        offset += self.offset;
+        let mut page_index = offset >> bindings::PAGE_SHIFT;
+        offset &= (1 << bindings::PAGE_SHIFT) - 1;
+        while size > 0 {
+            let available = core::cmp::min(size, (1 << bindings::PAGE_SHIFT) as usize - offset);
+            cb(&self.pages[page_index], offset, available)?;
+            size -= available;
+            page_index += 1;
+            offset = 0;
+        }
+        Ok(())
+    }
+
+    pub(crate) fn copy_into(
+        &self,
+        reader: &mut UserSlicePtrReader,
+        offset: usize,
+        size: usize,
+    ) -> Result {
+        self.iterate(offset, size, |page, offset, to_copy| {
+            page.copy_into_page(reader, offset, to_copy)
+        })
+    }
+
+    pub(crate) fn read<T>(&self, offset: usize) -> Result<T> {
+        let mut out = MaybeUninit::<T>::uninit();
+        let mut out_offset = 0;
+        self.iterate(offset, size_of::<T>(), |page, offset, to_copy| {
+            // SAFETY: Data buffer is allocated on the stack.
+            unsafe {
+                page.read(
+                    (out.as_mut_ptr() as *mut u8).add(out_offset),
+                    offset,
+                    to_copy,
+                )
+            }?;
+            out_offset += to_copy;
+            Ok(())
+        })?;
+        // SAFETY: We just initialised the data.
+        Ok(unsafe { out.assume_init() })
+    }
+
+    pub(crate) fn write<T>(&self, offset: usize, obj: &T) -> Result {
+        let mut obj_offset = 0;
+        self.iterate(offset, size_of::<T>(), |page, offset, to_copy| {
+            // SAFETY: The sum of `offset` and `to_copy` is bounded by the size of T.
+            let obj_ptr = unsafe { (obj as *const T as *const u8).add(obj_offset) };
+            // SAFETY: We have a reference to the object, so the pointer is valid.
+            unsafe { page.write(obj_ptr, offset, to_copy) }?;
+            obj_offset += to_copy;
+            Ok(())
+        })
+    }
+
+    pub(crate) fn keep_alive(mut self) {
+        self.process
+            .buffer_make_freeable(self.offset, self.allocation_info.take());
+        self.free_on_drop = false;
+    }
+
+    pub(crate) fn set_info(&mut self, info: AllocationInfo) {
+        self.allocation_info = Some(info);
+    }
+}
+
+impl Drop for Allocation<'_> {
+    fn drop(&mut self) {
+        if !self.free_on_drop {
+            return;
+        }
+
+        if let Some(info) = &self.allocation_info {
+            let offsets = info.offsets.clone();
+            let view = AllocationView::new(self, offsets.start);
+            for i in offsets.step_by(size_of::<usize>()) {
+                if view.cleanup_object(i).is_err() {
+                    pr_warn!("Error cleaning up object at offset {}\n", i)
+                }
+            }
+        }
+
+        self.process.buffer_raw_free(self.ptr);
+    }
+}
+
+pub(crate) struct AllocationView<'a, 'b> {
+    pub(crate) alloc: &'a mut Allocation<'b>,
+    limit: usize,
+}
+
+impl<'a, 'b> AllocationView<'a, 'b> {
+    pub(crate) fn new(alloc: &'a mut Allocation<'b>, limit: usize) -> Self {
+        AllocationView { alloc, limit }
+    }
+
+    pub(crate) fn read<T>(&self, offset: usize) -> Result<T> {
+        if offset.checked_add(size_of::<T>()).ok_or(EINVAL)? > self.limit {
+            return Err(EINVAL);
+        }
+        self.alloc.read(offset)
+    }
+
+    pub(crate) fn write<T>(&self, offset: usize, obj: &T) -> Result {
+        if offset.checked_add(size_of::<T>()).ok_or(EINVAL)? > self.limit {
+            return Err(EINVAL);
+        }
+        self.alloc.write(offset, obj)
+    }
+
+    pub(crate) fn transfer_binder_object<T>(
+        &self,
+        offset: usize,
+        strong: bool,
+        get_node: T,
+    ) -> BinderResult
+    where
+        T: FnOnce(&bindings::flat_binder_object) -> BinderResult<NodeRef>,
+    {
+        // TODO: Do we want this function to take a &mut self?
+        let obj = self.read::<bindings::flat_binder_object>(offset)?;
+        let node_ref = get_node(&obj)?;
+
+        if core::ptr::eq(&*node_ref.node.owner, self.alloc.process) {
+            // The receiving process is the owner of the node, so send it a binder object (instead
+            // of a handle).
+            let (ptr, cookie) = node_ref.node.get_id();
+            let newobj = bindings::flat_binder_object {
+                hdr: bindings::binder_object_header {
+                    type_: if strong {
+                        BINDER_TYPE_BINDER
+                    } else {
+                        BINDER_TYPE_WEAK_BINDER
+                    },
+                },
+                flags: obj.flags,
+                __bindgen_anon_1: bindings::flat_binder_object__bindgen_ty_1 { binder: ptr as _ },
+                cookie: cookie as _,
+            };
+            self.write(offset, &newobj)?;
+
+            // Increment the user ref count on the node. It will be decremented as part of the
+            // destruction of the buffer, when we see a binder or weak-binder object.
+            node_ref.node.update_refcount(true, strong);
+        } else {
+            // The receiving process is different from the owner, so we need to insert a handle to
+            // the binder object.
+            let handle = self
+                .alloc
+                .process
+                .insert_or_update_handle(node_ref, false)?;
+
+            let newobj = bindings::flat_binder_object {
+                hdr: bindings::binder_object_header {
+                    type_: if strong {
+                        BINDER_TYPE_HANDLE
+                    } else {
+                        BINDER_TYPE_WEAK_HANDLE
+                    },
+                },
+                flags: obj.flags,
+                // TODO: To avoid padding, we write to `binder` instead of `handle` here. We need a
+                // better solution though.
+                __bindgen_anon_1: bindings::flat_binder_object__bindgen_ty_1 {
+                    binder: handle as _,
+                },
+                ..bindings::flat_binder_object::default()
+            };
+            if self.write(offset, &newobj).is_err() {
+                // Decrement ref count on the handle we just created.
+                let _ = self.alloc.process.update_ref(handle, false, strong);
+                return Err(BinderError::new_failed());
+            }
+        }
+        Ok(())
+    }
+
+    fn cleanup_object(&self, index_offset: usize) -> Result {
+        let offset = self.alloc.read(index_offset)?;
+        let header = self.read::<bindings::binder_object_header>(offset)?;
+        // TODO: Handle other types.
+        match header.type_ {
+            BINDER_TYPE_WEAK_BINDER | BINDER_TYPE_BINDER => {
+                let obj = self.read::<bindings::flat_binder_object>(offset)?;
+                let strong = header.type_ == BINDER_TYPE_BINDER;
+                // SAFETY: The type is `BINDER_TYPE_{WEAK_}BINDER`, so the `binder` field is
+                // populated.
+                let ptr = unsafe { obj.__bindgen_anon_1.binder } as usize;
+                let cookie = obj.cookie as usize;
+                self.alloc.process.update_node(ptr, cookie, strong, false);
+                Ok(())
+            }
+            BINDER_TYPE_WEAK_HANDLE | BINDER_TYPE_HANDLE => {
+                let obj = self.read::<bindings::flat_binder_object>(offset)?;
+                let strong = header.type_ == BINDER_TYPE_HANDLE;
+                // SAFETY: The type is `BINDER_TYPE_{WEAK_}HANDLE`, so the `handle` field is
+                // populated.
+                let handle = unsafe { obj.__bindgen_anon_1.handle } as _;
+                self.alloc.process.update_ref(handle, false, strong)
+            }
+            _ => Ok(()),
+        }
+    }
+}
diff --git a/drivers/android/context.rs b/drivers/android/context.rs
new file mode 100644
index 000000000000..2bb448df6641
--- /dev/null
+++ b/drivers/android/context.rs
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use kernel::{
+    bindings,
+    prelude::*,
+    security,
+    sync::{Mutex, Ref, UniqueRef},
+};
+
+use crate::{
+    node::NodeRef,
+    thread::{BinderError, BinderResult},
+};
+
+struct Manager {
+    node: Option<NodeRef>,
+    uid: Option<bindings::kuid_t>,
+}
+
+pub(crate) struct Context {
+    manager: Mutex<Manager>,
+}
+
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl Send for Context {}
+unsafe impl Sync for Context {}
+
+impl Context {
+    pub(crate) fn new() -> Result<Ref<Self>> {
+        let mut ctx = Pin::from(UniqueRef::try_new(Self {
+            // SAFETY: Init is called below.
+            manager: unsafe {
+                Mutex::new(Manager {
+                    node: None,
+                    uid: None,
+                })
+            },
+        })?);
+
+        // SAFETY: `manager` is also pinned when `ctx` is.
+        let manager = unsafe { ctx.as_mut().map_unchecked_mut(|c| &mut c.manager) };
+        kernel::mutex_init!(manager, "Context::manager");
+
+        Ok(ctx.into())
+    }
+
+    pub(crate) fn set_manager_node(&self, node_ref: NodeRef) -> Result {
+        let mut manager = self.manager.lock();
+        if manager.node.is_some() {
+            return Err(EBUSY);
+        }
+        security::binder_set_context_mgr(&node_ref.node.owner.cred)?;
+
+        // TODO: Get the actual caller id.
+        let caller_uid = bindings::kuid_t::default();
+        if let Some(ref uid) = manager.uid {
+            if uid.val != caller_uid.val {
+                return Err(EPERM);
+            }
+        }
+
+        manager.node = Some(node_ref);
+        manager.uid = Some(caller_uid);
+        Ok(())
+    }
+
+    pub(crate) fn unset_manager_node(&self) {
+        let node_ref = self.manager.lock().node.take();
+        drop(node_ref);
+    }
+
+    pub(crate) fn get_manager_node(&self, strong: bool) -> BinderResult<NodeRef> {
+        self.manager
+            .lock()
+            .node
+            .as_ref()
+            .ok_or_else(BinderError::new_dead)?
+            .clone(strong)
+    }
+}
diff --git a/drivers/android/defs.rs b/drivers/android/defs.rs
new file mode 100644
index 000000000000..925e751a2564
--- /dev/null
+++ b/drivers/android/defs.rs
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::ops::{Deref, DerefMut};
+use kernel::{
+    bindings,
+    bindings::*,
+    io_buffer::{ReadableFromBytes, WritableToBytes},
+};
+
+macro_rules! pub_no_prefix {
+    ($prefix:ident, $($newname:ident),+) => {
+        $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+
+    };
+}
+
+pub_no_prefix!(
+    binder_driver_return_protocol_,
+    BR_OK,
+    BR_ERROR,
+    BR_TRANSACTION,
+    BR_REPLY,
+    BR_DEAD_REPLY,
+    BR_TRANSACTION_COMPLETE,
+    BR_INCREFS,
+    BR_ACQUIRE,
+    BR_RELEASE,
+    BR_DECREFS,
+    BR_NOOP,
+    BR_SPAWN_LOOPER,
+    BR_DEAD_BINDER,
+    BR_CLEAR_DEATH_NOTIFICATION_DONE,
+    BR_FAILED_REPLY
+);
+
+pub_no_prefix!(
+    binder_driver_command_protocol_,
+    BC_TRANSACTION,
+    BC_REPLY,
+    BC_FREE_BUFFER,
+    BC_INCREFS,
+    BC_ACQUIRE,
+    BC_RELEASE,
+    BC_DECREFS,
+    BC_INCREFS_DONE,
+    BC_ACQUIRE_DONE,
+    BC_REGISTER_LOOPER,
+    BC_ENTER_LOOPER,
+    BC_EXIT_LOOPER,
+    BC_REQUEST_DEATH_NOTIFICATION,
+    BC_CLEAR_DEATH_NOTIFICATION,
+    BC_DEAD_BINDER_DONE
+);
+
+pub_no_prefix!(transaction_flags_, TF_ONE_WAY, TF_ACCEPT_FDS);
+
+pub(crate) use bindings::{
+    BINDER_TYPE_BINDER, BINDER_TYPE_FD, BINDER_TYPE_HANDLE, BINDER_TYPE_WEAK_BINDER,
+    BINDER_TYPE_WEAK_HANDLE, FLAT_BINDER_FLAG_ACCEPTS_FDS,
+};
+
+macro_rules! decl_wrapper {
+    ($newname:ident, $wrapped:ty) => {
+        #[derive(Copy, Clone, Default)]
+        pub(crate) struct $newname($wrapped);
+
+        // TODO: This must be justified by inspecting the type, so should live outside the macro or
+        // the macro should be somehow marked unsafe.
+        unsafe impl ReadableFromBytes for $newname {}
+        unsafe impl WritableToBytes for $newname {}
+
+        impl Deref for $newname {
+            type Target = $wrapped;
+            fn deref(&self) -> &Self::Target {
+                &self.0
+            }
+        }
+
+        impl DerefMut for $newname {
+            fn deref_mut(&mut self) -> &mut Self::Target {
+                &mut self.0
+            }
+        }
+    };
+}
+
+decl_wrapper!(BinderNodeDebugInfo, bindings::binder_node_debug_info);
+decl_wrapper!(BinderNodeInfoForRef, bindings::binder_node_info_for_ref);
+decl_wrapper!(FlatBinderObject, bindings::flat_binder_object);
+decl_wrapper!(BinderTransactionData, bindings::binder_transaction_data);
+decl_wrapper!(BinderWriteRead, bindings::binder_write_read);
+decl_wrapper!(BinderVersion, bindings::binder_version);
+
+impl BinderVersion {
+    pub(crate) fn current() -> Self {
+        Self(bindings::binder_version {
+            protocol_version: bindings::BINDER_CURRENT_PROTOCOL_VERSION as _,
+        })
+    }
+}
diff --git a/drivers/android/node.rs b/drivers/android/node.rs
new file mode 100644
index 000000000000..1a46de1e736c
--- /dev/null
+++ b/drivers/android/node.rs
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::sync::atomic::{AtomicU64, Ordering};
+use kernel::{
+    io_buffer::IoBufferWriter,
+    linked_list::{GetLinks, Links, List},
+    prelude::*,
+    sync::{Guard, LockedBy, Mutex, Ref, SpinLock},
+    user_ptr::UserSlicePtrWriter,
+};
+
+use crate::{
+    defs::*,
+    process::{Process, ProcessInner},
+    thread::{BinderError, BinderResult, Thread},
+    DeliverToRead,
+};
+
+struct CountState {
+    count: usize,
+    has_count: bool,
+    is_biased: bool,
+}
+
+impl CountState {
+    fn new() -> Self {
+        Self {
+            count: 0,
+            has_count: false,
+            is_biased: false,
+        }
+    }
+
+    fn add_bias(&mut self) {
+        self.count += 1;
+        self.is_biased = true;
+    }
+}
+
+struct NodeInner {
+    strong: CountState,
+    weak: CountState,
+    death_list: List<Ref<NodeDeath>>,
+}
+
+struct NodeDeathInner {
+    dead: bool,
+    cleared: bool,
+    notification_done: bool,
+
+    /// Indicates whether the normal flow was interrupted by removing the handle. In this case, we
+    /// need behave as if the death notification didn't exist (i.e., we don't deliver anything to
+    /// the user.
+    aborted: bool,
+}
+
+pub(crate) struct NodeDeath {
+    node: Ref<Node>,
+    process: Ref<Process>,
+    // TODO: Make this private.
+    pub(crate) cookie: usize,
+    work_links: Links<dyn DeliverToRead>,
+    // TODO: Add the moment we're using this for two lists, which isn't safe because we want to
+    // remove from the list without knowing the list it's in. We need to separate this out.
+    death_links: Links<NodeDeath>,
+    inner: SpinLock<NodeDeathInner>,
+}
+
+impl NodeDeath {
+    /// Constructs a new node death notification object.
+    ///
+    /// # Safety
+    ///
+    /// The caller must call `NodeDeath::init` before using the notification object.
+    pub(crate) unsafe fn new(node: Ref<Node>, process: Ref<Process>, cookie: usize) -> Self {
+        Self {
+            node,
+            process,
+            cookie,
+            work_links: Links::new(),
+            death_links: Links::new(),
+            inner: unsafe {
+                SpinLock::new(NodeDeathInner {
+                    dead: false,
+                    cleared: false,
+                    notification_done: false,
+                    aborted: false,
+                })
+            },
+        }
+    }
+
+    pub(crate) fn init(self: Pin<&mut Self>) {
+        // SAFETY: `inner` is pinned when `self` is.
+        let inner = unsafe { self.map_unchecked_mut(|n| &mut n.inner) };
+        kernel::spinlock_init!(inner, "NodeDeath::inner");
+    }
+
+    /// Sets the cleared flag to `true`.
+    ///
+    /// It removes `self` from the node's death notification list if needed. It must only be called
+    /// once.
+    ///
+    /// Returns whether it needs to be queued.
+    pub(crate) fn set_cleared(self: &Ref<Self>, abort: bool) -> bool {
+        let (needs_removal, needs_queueing) = {
+            // Update state and determine if we need to queue a work item. We only need to do it
+            // when the node is not dead or if the user already completed the death notification.
+            let mut inner = self.inner.lock();
+            inner.cleared = true;
+            if abort {
+                inner.aborted = true;
+            }
+            (!inner.dead, !inner.dead || inner.notification_done)
+        };
+
+        // Remove death notification from node.
+        if needs_removal {
+            let mut owner_inner = self.node.owner.inner.lock();
+            let node_inner = self.node.inner.access_mut(&mut owner_inner);
+            unsafe { node_inner.death_list.remove(self) };
+        }
+
+        needs_queueing
+    }
+
+    /// Sets the 'notification done' flag to `true`.
+    ///
+    /// Returns whether it needs to be queued.
+    pub(crate) fn set_notification_done(self: Ref<Self>, thread: &Thread) {
+        let needs_queueing = {
+            let mut inner = self.inner.lock();
+            inner.notification_done = true;
+            inner.cleared
+        };
+
+        if needs_queueing {
+            let _ = thread.push_work_if_looper(self);
+        }
+    }
+
+    /// Sets the 'dead' flag to `true` and queues work item if needed.
+    pub(crate) fn set_dead(self: Ref<Self>) {
+        let needs_queueing = {
+            let mut inner = self.inner.lock();
+            if inner.cleared {
+                false
+            } else {
+                inner.dead = true;
+                true
+            }
+        };
+
+        if needs_queueing {
+            // Push the death notification to the target process. There is nothing else to do if
+            // it's already dead.
+            let process = self.process.clone();
+            let _ = process.push_work(self);
+        }
+    }
+}
+
+impl GetLinks for NodeDeath {
+    type EntryType = NodeDeath;
+    fn get_links(data: &NodeDeath) -> &Links<NodeDeath> {
+        &data.death_links
+    }
+}
+
+impl DeliverToRead for NodeDeath {
+    fn do_work(self: Ref<Self>, _thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+        let done = {
+            let inner = self.inner.lock();
+            if inner.aborted {
+                return Ok(true);
+            }
+            inner.cleared && (!inner.dead || inner.notification_done)
+        };
+
+        let cookie = self.cookie;
+        let cmd = if done {
+            BR_CLEAR_DEATH_NOTIFICATION_DONE
+        } else {
+            let process = self.process.clone();
+            let mut process_inner = process.inner.lock();
+            let inner = self.inner.lock();
+            if inner.aborted {
+                return Ok(true);
+            }
+            // We're still holding the inner lock, so it cannot be aborted while we insert it into
+            // the delivered list.
+            process_inner.death_delivered(self.clone());
+            BR_DEAD_BINDER
+        };
+
+        writer.write(&cmd)?;
+        writer.write(&cookie)?;
+
+        // Mimic the original code: we stop processing work items when we get to a death
+        // notification.
+        Ok(cmd != BR_DEAD_BINDER)
+    }
+
+    fn get_links(&self) -> &Links<dyn DeliverToRead> {
+        &self.work_links
+    }
+}
+
+pub(crate) struct Node {
+    pub(crate) global_id: u64,
+    ptr: usize,
+    cookie: usize,
+    pub(crate) flags: u32,
+    pub(crate) owner: Ref<Process>,
+    inner: LockedBy<NodeInner, Mutex<ProcessInner>>,
+    links: Links<dyn DeliverToRead>,
+}
+
+impl Node {
+    pub(crate) fn new(ptr: usize, cookie: usize, flags: u32, owner: Ref<Process>) -> Self {
+        static NEXT_ID: AtomicU64 = AtomicU64::new(1);
+        let inner = LockedBy::new(
+            &owner.inner,
+            NodeInner {
+                strong: CountState::new(),
+                weak: CountState::new(),
+                death_list: List::new(),
+            },
+        );
+        Self {
+            global_id: NEXT_ID.fetch_add(1, Ordering::Relaxed),
+            ptr,
+            cookie,
+            flags,
+            owner,
+            inner,
+            links: Links::new(),
+        }
+    }
+
+    pub(crate) fn get_id(&self) -> (usize, usize) {
+        (self.ptr, self.cookie)
+    }
+
+    pub(crate) fn next_death(
+        &self,
+        guard: &mut Guard<'_, Mutex<ProcessInner>>,
+    ) -> Option<Ref<NodeDeath>> {
+        self.inner.access_mut(guard).death_list.pop_front()
+    }
+
+    pub(crate) fn add_death(
+        &self,
+        death: Ref<NodeDeath>,
+        guard: &mut Guard<'_, Mutex<ProcessInner>>,
+    ) {
+        self.inner.access_mut(guard).death_list.push_back(death);
+    }
+
+    pub(crate) fn update_refcount_locked(
+        &self,
+        inc: bool,
+        strong: bool,
+        biased: bool,
+        owner_inner: &mut ProcessInner,
+    ) -> bool {
+        let inner = self.inner.access_from_mut(owner_inner);
+
+        // Get a reference to the state we'll update.
+        let state = if strong {
+            &mut inner.strong
+        } else {
+            &mut inner.weak
+        };
+
+        // Update biased state: if the count is not biased, there is nothing to do; otherwise,
+        // we're removing the bias, so mark the state as such.
+        if biased {
+            if !state.is_biased {
+                return false;
+            }
+
+            state.is_biased = false;
+        }
+
+        // Update the count and determine whether we need to push work.
+        // TODO: Here we may want to check the weak count being zero but the strong count being 1,
+        // because in such cases, we won't deliver anything to userspace, so we shouldn't queue
+        // either.
+        if inc {
+            state.count += 1;
+            !state.has_count
+        } else {
+            state.count -= 1;
+            state.count == 0 && state.has_count
+        }
+    }
+
+    pub(crate) fn update_refcount(self: &Ref<Self>, inc: bool, strong: bool) {
+        self.owner
+            .inner
+            .lock()
+            .update_node_refcount(self, inc, strong, false, None);
+    }
+
+    pub(crate) fn populate_counts(
+        &self,
+        out: &mut BinderNodeInfoForRef,
+        guard: &Guard<'_, Mutex<ProcessInner>>,
+    ) {
+        let inner = self.inner.access(guard);
+        out.strong_count = inner.strong.count as _;
+        out.weak_count = inner.weak.count as _;
+    }
+
+    pub(crate) fn populate_debug_info(
+        &self,
+        out: &mut BinderNodeDebugInfo,
+        guard: &Guard<'_, Mutex<ProcessInner>>,
+    ) {
+        out.ptr = self.ptr as _;
+        out.cookie = self.cookie as _;
+        let inner = self.inner.access(guard);
+        if inner.strong.has_count {
+            out.has_strong_ref = 1;
+        }
+        if inner.weak.has_count {
+            out.has_weak_ref = 1;
+        }
+    }
+
+    pub(crate) fn force_has_count(&self, guard: &mut Guard<'_, Mutex<ProcessInner>>) {
+        let inner = self.inner.access_mut(guard);
+        inner.strong.has_count = true;
+        inner.weak.has_count = true;
+    }
+
+    fn write(&self, writer: &mut UserSlicePtrWriter, code: u32) -> Result {
+        writer.write(&code)?;
+        writer.write(&self.ptr)?;
+        writer.write(&self.cookie)?;
+        Ok(())
+    }
+}
+
+impl DeliverToRead for Node {
+    fn do_work(self: Ref<Self>, _thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+        let mut owner_inner = self.owner.inner.lock();
+        let inner = self.inner.access_mut(&mut owner_inner);
+        let strong = inner.strong.count > 0;
+        let has_strong = inner.strong.has_count;
+        let weak = strong || inner.weak.count > 0;
+        let has_weak = inner.weak.has_count;
+        inner.weak.has_count = weak;
+        inner.strong.has_count = strong;
+
+        if !weak {
+            // Remove the node if there are no references to it.
+            owner_inner.remove_node(self.ptr);
+        } else {
+            if !has_weak {
+                inner.weak.add_bias();
+            }
+
+            if !has_strong && strong {
+                inner.strong.add_bias();
+            }
+        }
+
+        drop(owner_inner);
+
+        // This could be done more compactly but we write out all the posibilities for
+        // compatibility with the original implementation wrt the order of events.
+        if weak && !has_weak {
+            self.write(writer, BR_INCREFS)?;
+        }
+
+        if strong && !has_strong {
+            self.write(writer, BR_ACQUIRE)?;
+        }
+
+        if !strong && has_strong {
+            self.write(writer, BR_RELEASE)?;
+        }
+
+        if !weak && has_weak {
+            self.write(writer, BR_DECREFS)?;
+        }
+
+        Ok(true)
+    }
+
+    fn get_links(&self) -> &Links<dyn DeliverToRead> {
+        &self.links
+    }
+}
+
+pub(crate) struct NodeRef {
+    pub(crate) node: Ref<Node>,
+    strong_count: usize,
+    weak_count: usize,
+}
+
+impl NodeRef {
+    pub(crate) fn new(node: Ref<Node>, strong_count: usize, weak_count: usize) -> Self {
+        Self {
+            node,
+            strong_count,
+            weak_count,
+        }
+    }
+
+    pub(crate) fn absorb(&mut self, mut other: Self) {
+        self.strong_count += other.strong_count;
+        self.weak_count += other.weak_count;
+        other.strong_count = 0;
+        other.weak_count = 0;
+    }
+
+    pub(crate) fn clone(&self, strong: bool) -> BinderResult<NodeRef> {
+        if strong && self.strong_count == 0 {
+            return Err(BinderError::new_failed());
+        }
+
+        Ok(self
+            .node
+            .owner
+            .inner
+            .lock()
+            .new_node_ref(self.node.clone(), strong, None))
+    }
+
+    /// Updates (increments or decrements) the number of references held against the node. If the
+    /// count being updated transitions from 0 to 1 or from 1 to 0, the node is notified by having
+    /// its `update_refcount` function called.
+    ///
+    /// Returns whether `self` should be removed (when both counts are zero).
+    pub(crate) fn update(&mut self, inc: bool, strong: bool) -> bool {
+        if strong && self.strong_count == 0 {
+            return false;
+        }
+
+        let (count, other_count) = if strong {
+            (&mut self.strong_count, self.weak_count)
+        } else {
+            (&mut self.weak_count, self.strong_count)
+        };
+
+        if inc {
+            if *count == 0 {
+                self.node.update_refcount(true, strong);
+            }
+            *count += 1;
+        } else {
+            *count -= 1;
+            if *count == 0 {
+                self.node.update_refcount(false, strong);
+                return other_count == 0;
+            }
+        }
+
+        false
+    }
+}
+
+impl Drop for NodeRef {
+    fn drop(&mut self) {
+        if self.strong_count > 0 {
+            self.node.update_refcount(false, true);
+        }
+
+        if self.weak_count > 0 {
+            self.node.update_refcount(false, false);
+        }
+    }
+}
diff --git a/drivers/android/process.rs b/drivers/android/process.rs
new file mode 100644
index 000000000000..229493f0d7a1
--- /dev/null
+++ b/drivers/android/process.rs
@@ -0,0 +1,961 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::{convert::TryFrom, mem::take, ops::Range};
+use kernel::{
+    bindings,
+    cred::Credential,
+    file::{self, File, IoctlCommand, IoctlHandler, PollTable},
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    linked_list::List,
+    mm,
+    pages::Pages,
+    prelude::*,
+    rbtree::RBTree,
+    sync::{Guard, Mutex, Ref, RefBorrow, UniqueRef},
+    task::Task,
+    user_ptr::{UserSlicePtr, UserSlicePtrReader},
+    Either,
+};
+
+use crate::{
+    allocation::Allocation,
+    context::Context,
+    defs::*,
+    node::{Node, NodeDeath, NodeRef},
+    range_alloc::RangeAllocator,
+    thread::{BinderError, BinderResult, Thread},
+    DeliverToRead, DeliverToReadListAdapter,
+};
+
+// TODO: Review this:
+// Lock order: Process::node_refs -> Process::inner -> Thread::inner
+
+pub(crate) struct AllocationInfo {
+    /// Range within the allocation where we can find the offsets to the object descriptors.
+    pub(crate) offsets: Range<usize>,
+}
+
+struct Mapping {
+    address: usize,
+    alloc: RangeAllocator<AllocationInfo>,
+    pages: Ref<[Pages<0>]>,
+}
+
+impl Mapping {
+    fn new(address: usize, size: usize, pages: Ref<[Pages<0>]>) -> Result<Self> {
+        let alloc = RangeAllocator::new(size)?;
+        Ok(Self {
+            address,
+            alloc,
+            pages,
+        })
+    }
+}
+
+// TODO: Make this private.
+pub(crate) struct ProcessInner {
+    is_manager: bool,
+    is_dead: bool,
+    threads: RBTree<i32, Ref<Thread>>,
+    ready_threads: List<Ref<Thread>>,
+    work: List<DeliverToReadListAdapter>,
+    mapping: Option<Mapping>,
+    nodes: RBTree<usize, Ref<Node>>,
+
+    delivered_deaths: List<Ref<NodeDeath>>,
+
+    /// The number of requested threads that haven't registered yet.
+    requested_thread_count: u32,
+
+    /// The maximum number of threads used by the process thread pool.
+    max_threads: u32,
+
+    /// The number of threads the started and registered with the thread pool.
+    started_thread_count: u32,
+}
+
+impl ProcessInner {
+    fn new() -> Self {
+        Self {
+            is_manager: false,
+            is_dead: false,
+            threads: RBTree::new(),
+            ready_threads: List::new(),
+            work: List::new(),
+            mapping: None,
+            nodes: RBTree::new(),
+            requested_thread_count: 0,
+            max_threads: 0,
+            started_thread_count: 0,
+            delivered_deaths: List::new(),
+        }
+    }
+
+    fn push_work(&mut self, work: Ref<dyn DeliverToRead>) -> BinderResult {
+        // Try to find a ready thread to which to push the work.
+        if let Some(thread) = self.ready_threads.pop_front() {
+            // Push to thread while holding state lock. This prevents the thread from giving up
+            // (for example, because of a signal) when we're about to deliver work.
+            thread.push_work(work)
+        } else if self.is_dead {
+            Err(BinderError::new_dead())
+        } else {
+            // There are no ready threads. Push work to process queue.
+            self.work.push_back(work);
+
+            // Wake up polling threads, if any.
+            for thread in self.threads.values() {
+                thread.notify_if_poll_ready();
+            }
+            Ok(())
+        }
+    }
+
+    // TODO: Should this be private?
+    pub(crate) fn remove_node(&mut self, ptr: usize) {
+        self.nodes.remove(&ptr);
+    }
+
+    /// Updates the reference count on the given node.
+    // TODO: Decide if this should be private.
+    pub(crate) fn update_node_refcount(
+        &mut self,
+        node: &Ref<Node>,
+        inc: bool,
+        strong: bool,
+        biased: bool,
+        othread: Option<&Thread>,
+    ) {
+        let push = node.update_refcount_locked(inc, strong, biased, self);
+
+        // If we decided that we need to push work, push either to the process or to a thread if
+        // one is specified.
+        if push {
+            if let Some(thread) = othread {
+                thread.push_work_deferred(node.clone());
+            } else {
+                let _ = self.push_work(node.clone());
+                // Nothing to do: `push_work` may fail if the process is dead, but that's ok as in
+                // that case, it doesn't care about the notification.
+            }
+        }
+    }
+
+    // TODO: Make this private.
+    pub(crate) fn new_node_ref(
+        &mut self,
+        node: Ref<Node>,
+        strong: bool,
+        thread: Option<&Thread>,
+    ) -> NodeRef {
+        self.update_node_refcount(&node, true, strong, false, thread);
+        let strong_count = if strong { 1 } else { 0 };
+        NodeRef::new(node, strong_count, 1 - strong_count)
+    }
+
+    /// Returns an existing node with the given pointer and cookie, if one exists.
+    ///
+    /// Returns an error if a node with the given pointer but a different cookie exists.
+    fn get_existing_node(&self, ptr: usize, cookie: usize) -> Result<Option<Ref<Node>>> {
+        match self.nodes.get(&ptr) {
+            None => Ok(None),
+            Some(node) => {
+                let (_, node_cookie) = node.get_id();
+                if node_cookie == cookie {
+                    Ok(Some(node.clone()))
+                } else {
+                    Err(EINVAL)
+                }
+            }
+        }
+    }
+
+    /// Returns a reference to an existing node with the given pointer and cookie. It requires a
+    /// mutable reference because it needs to increment the ref count on the node, which may
+    /// require pushing work to the work queue (to notify userspace of 0 to 1 transitions).
+    fn get_existing_node_ref(
+        &mut self,
+        ptr: usize,
+        cookie: usize,
+        strong: bool,
+        thread: Option<&Thread>,
+    ) -> Result<Option<NodeRef>> {
+        Ok(self
+            .get_existing_node(ptr, cookie)?
+            .map(|node| self.new_node_ref(node, strong, thread)))
+    }
+
+    fn register_thread(&mut self) -> bool {
+        if self.requested_thread_count == 0 {
+            return false;
+        }
+
+        self.requested_thread_count -= 1;
+        self.started_thread_count += 1;
+        true
+    }
+
+    /// Finds a delivered death notification with the given cookie, removes it from the thread's
+    /// delivered list, and returns it.
+    fn pull_delivered_death(&mut self, cookie: usize) -> Option<Ref<NodeDeath>> {
+        let mut cursor = self.delivered_deaths.cursor_front_mut();
+        while let Some(death) = cursor.current() {
+            if death.cookie == cookie {
+                return cursor.remove_current();
+            }
+            cursor.move_next();
+        }
+        None
+    }
+
+    pub(crate) fn death_delivered(&mut self, death: Ref<NodeDeath>) {
+        self.delivered_deaths.push_back(death);
+    }
+}
+
+struct NodeRefInfo {
+    node_ref: NodeRef,
+    death: Option<Ref<NodeDeath>>,
+}
+
+impl NodeRefInfo {
+    fn new(node_ref: NodeRef) -> Self {
+        Self {
+            node_ref,
+            death: None,
+        }
+    }
+}
+
+struct ProcessNodeRefs {
+    by_handle: RBTree<u32, NodeRefInfo>,
+    by_global_id: RBTree<u64, u32>,
+}
+
+impl ProcessNodeRefs {
+    fn new() -> Self {
+        Self {
+            by_handle: RBTree::new(),
+            by_global_id: RBTree::new(),
+        }
+    }
+}
+
+pub(crate) struct Process {
+    ctx: Ref<Context>,
+
+    // The task leader (process).
+    pub(crate) task: ARef<Task>,
+
+    // Credential associated with file when `Process` is created.
+    pub(crate) cred: ARef<Credential>,
+
+    // TODO: For now this a mutex because we have allocations in RangeAllocator while holding the
+    // lock. We may want to split up the process state at some point to use a spin lock for the
+    // other fields.
+    // TODO: Make this private again.
+    pub(crate) inner: Mutex<ProcessInner>,
+
+    // References are in a different mutex to avoid recursive acquisition when
+    // incrementing/decrementing a node in another process.
+    node_refs: Mutex<ProcessNodeRefs>,
+}
+
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl Send for Process {}
+unsafe impl Sync for Process {}
+
+impl Process {
+    fn new(ctx: Ref<Context>, cred: ARef<Credential>) -> Result<Ref<Self>> {
+        let mut process = Pin::from(UniqueRef::try_new(Self {
+            ctx,
+            cred,
+            task: Task::current().group_leader().into(),
+            // SAFETY: `inner` is initialised in the call to `mutex_init` below.
+            inner: unsafe { Mutex::new(ProcessInner::new()) },
+            // SAFETY: `node_refs` is initialised in the call to `mutex_init` below.
+            node_refs: unsafe { Mutex::new(ProcessNodeRefs::new()) },
+        })?);
+
+        // SAFETY: `inner` is pinned when `Process` is.
+        let pinned = unsafe { process.as_mut().map_unchecked_mut(|p| &mut p.inner) };
+        kernel::mutex_init!(pinned, "Process::inner");
+
+        // SAFETY: `node_refs` is pinned when `Process` is.
+        let pinned = unsafe { process.as_mut().map_unchecked_mut(|p| &mut p.node_refs) };
+        kernel::mutex_init!(pinned, "Process::node_refs");
+
+        Ok(process.into())
+    }
+
+    /// Attempts to fetch a work item from the process queue.
+    pub(crate) fn get_work(&self) -> Option<Ref<dyn DeliverToRead>> {
+        self.inner.lock().work.pop_front()
+    }
+
+    /// Attempts to fetch a work item from the process queue. If none is available, it registers the
+    /// given thread as ready to receive work directly.
+    ///
+    /// This must only be called when the thread is not participating in a transaction chain; when
+    /// it is, work will always be delivered directly to the thread (and not through the process
+    /// queue).
+    pub(crate) fn get_work_or_register<'a>(
+        &'a self,
+        thread: &'a Ref<Thread>,
+    ) -> Either<Ref<dyn DeliverToRead>, Registration<'a>> {
+        let mut inner = self.inner.lock();
+
+        // Try to get work from the process queue.
+        if let Some(work) = inner.work.pop_front() {
+            return Either::Left(work);
+        }
+
+        // Register the thread as ready.
+        Either::Right(Registration::new(self, thread, &mut inner))
+    }
+
+    fn get_thread(self: RefBorrow<'_, Self>, id: i32) -> Result<Ref<Thread>> {
+        // TODO: Consider using read/write locks here instead.
+        {
+            let inner = self.inner.lock();
+            if let Some(thread) = inner.threads.get(&id) {
+                return Ok(thread.clone());
+            }
+        }
+
+        // Allocate a new `Thread` without holding any locks.
+        let ta = Thread::new(id, self.into())?;
+        let node = RBTree::try_allocate_node(id, ta.clone())?;
+
+        let mut inner = self.inner.lock();
+
+        // Recheck. It's possible the thread was create while we were not holding the lock.
+        if let Some(thread) = inner.threads.get(&id) {
+            return Ok(thread.clone());
+        }
+
+        inner.threads.insert(node);
+        Ok(ta)
+    }
+
+    pub(crate) fn push_work(&self, work: Ref<dyn DeliverToRead>) -> BinderResult {
+        self.inner.lock().push_work(work)
+    }
+
+    fn set_as_manager(
+        self: RefBorrow<'_, Self>,
+        info: Option<FlatBinderObject>,
+        thread: &Thread,
+    ) -> Result {
+        let (ptr, cookie, flags) = if let Some(obj) = info {
+            (
+                // SAFETY: The object type for this ioctl is implicitly `BINDER_TYPE_BINDER`, so it
+                // is safe to access the `binder` field.
+                unsafe { obj.__bindgen_anon_1.binder },
+                obj.cookie,
+                obj.flags,
+            )
+        } else {
+            (0, 0, 0)
+        };
+        let node_ref = self.get_node(ptr as _, cookie as _, flags as _, true, Some(thread))?;
+        let node = node_ref.node.clone();
+        self.ctx.set_manager_node(node_ref)?;
+        self.inner.lock().is_manager = true;
+
+        // Force the state of the node to prevent the delivery of acquire/increfs.
+        let mut owner_inner = node.owner.inner.lock();
+        node.force_has_count(&mut owner_inner);
+        Ok(())
+    }
+
+    pub(crate) fn get_node(
+        self: RefBorrow<'_, Self>,
+        ptr: usize,
+        cookie: usize,
+        flags: u32,
+        strong: bool,
+        thread: Option<&Thread>,
+    ) -> Result<NodeRef> {
+        // Try to find an existing node.
+        {
+            let mut inner = self.inner.lock();
+            if let Some(node) = inner.get_existing_node_ref(ptr, cookie, strong, thread)? {
+                return Ok(node);
+            }
+        }
+
+        // Allocate the node before reacquiring the lock.
+        let node = Ref::try_new(Node::new(ptr, cookie, flags, self.into()))?;
+        let rbnode = RBTree::try_allocate_node(ptr, node.clone())?;
+
+        let mut inner = self.inner.lock();
+        if let Some(node) = inner.get_existing_node_ref(ptr, cookie, strong, thread)? {
+            return Ok(node);
+        }
+
+        inner.nodes.insert(rbnode);
+        Ok(inner.new_node_ref(node, strong, thread))
+    }
+
+    pub(crate) fn insert_or_update_handle(
+        &self,
+        node_ref: NodeRef,
+        is_mananger: bool,
+    ) -> Result<u32> {
+        {
+            let mut refs = self.node_refs.lock();
+
+            // Do a lookup before inserting.
+            if let Some(handle_ref) = refs.by_global_id.get(&node_ref.node.global_id) {
+                let handle = *handle_ref;
+                let info = refs.by_handle.get_mut(&handle).unwrap();
+                info.node_ref.absorb(node_ref);
+                return Ok(handle);
+            }
+        }
+
+        // Reserve memory for tree nodes.
+        let reserve1 = RBTree::try_reserve_node()?;
+        let reserve2 = RBTree::try_reserve_node()?;
+
+        let mut refs = self.node_refs.lock();
+
+        // Do a lookup again as node may have been inserted before the lock was reacquired.
+        if let Some(handle_ref) = refs.by_global_id.get(&node_ref.node.global_id) {
+            let handle = *handle_ref;
+            let info = refs.by_handle.get_mut(&handle).unwrap();
+            info.node_ref.absorb(node_ref);
+            return Ok(handle);
+        }
+
+        // Find id.
+        let mut target = if is_mananger { 0 } else { 1 };
+        for handle in refs.by_handle.keys() {
+            if *handle > target {
+                break;
+            }
+            if *handle == target {
+                target = target.checked_add(1).ok_or(ENOMEM)?;
+            }
+        }
+
+        // Ensure the process is still alive while we insert a new reference.
+        let inner = self.inner.lock();
+        if inner.is_dead {
+            return Err(ESRCH);
+        }
+        refs.by_global_id
+            .insert(reserve1.into_node(node_ref.node.global_id, target));
+        refs.by_handle
+            .insert(reserve2.into_node(target, NodeRefInfo::new(node_ref)));
+        Ok(target)
+    }
+
+    pub(crate) fn get_transaction_node(&self, handle: u32) -> BinderResult<NodeRef> {
+        // When handle is zero, try to get the context manager.
+        if handle == 0 {
+            self.ctx.get_manager_node(true)
+        } else {
+            self.get_node_from_handle(handle, true)
+        }
+    }
+
+    pub(crate) fn get_node_from_handle(&self, handle: u32, strong: bool) -> BinderResult<NodeRef> {
+        self.node_refs
+            .lock()
+            .by_handle
+            .get(&handle)
+            .ok_or(ENOENT)?
+            .node_ref
+            .clone(strong)
+    }
+
+    pub(crate) fn remove_from_delivered_deaths(&self, death: &Ref<NodeDeath>) {
+        let mut inner = self.inner.lock();
+        let removed = unsafe { inner.delivered_deaths.remove(death) };
+        drop(inner);
+        drop(removed);
+    }
+
+    pub(crate) fn update_ref(&self, handle: u32, inc: bool, strong: bool) -> Result {
+        if inc && handle == 0 {
+            if let Ok(node_ref) = self.ctx.get_manager_node(strong) {
+                if core::ptr::eq(self, &*node_ref.node.owner) {
+                    return Err(EINVAL);
+                }
+                let _ = self.insert_or_update_handle(node_ref, true);
+                return Ok(());
+            }
+        }
+
+        // To preserve original binder behaviour, we only fail requests where the manager tries to
+        // increment references on itself.
+        let mut refs = self.node_refs.lock();
+        if let Some(info) = refs.by_handle.get_mut(&handle) {
+            if info.node_ref.update(inc, strong) {
+                // Clean up death if there is one attached to this node reference.
+                if let Some(death) = info.death.take() {
+                    death.set_cleared(true);
+                    self.remove_from_delivered_deaths(&death);
+                }
+
+                // Remove reference from process tables.
+                let id = info.node_ref.node.global_id;
+                refs.by_handle.remove(&handle);
+                refs.by_global_id.remove(&id);
+            }
+        }
+        Ok(())
+    }
+
+    /// Decrements the refcount of the given node, if one exists.
+    pub(crate) fn update_node(&self, ptr: usize, cookie: usize, strong: bool, biased: bool) {
+        let mut inner = self.inner.lock();
+        if let Ok(Some(node)) = inner.get_existing_node(ptr, cookie) {
+            inner.update_node_refcount(&node, false, strong, biased, None);
+        }
+    }
+
+    pub(crate) fn inc_ref_done(&self, reader: &mut UserSlicePtrReader, strong: bool) -> Result {
+        let ptr = reader.read::<usize>()?;
+        let cookie = reader.read::<usize>()?;
+        self.update_node(ptr, cookie, strong, true);
+        Ok(())
+    }
+
+    pub(crate) fn buffer_alloc(&self, size: usize) -> BinderResult<Allocation<'_>> {
+        let mut inner = self.inner.lock();
+        let mapping = inner.mapping.as_mut().ok_or_else(BinderError::new_dead)?;
+
+        let offset = mapping.alloc.reserve_new(size)?;
+        Ok(Allocation::new(
+            self,
+            offset,
+            size,
+            mapping.address + offset,
+            mapping.pages.clone(),
+        ))
+    }
+
+    // TODO: Review if we want an Option or a Result.
+    pub(crate) fn buffer_get(&self, ptr: usize) -> Option<Allocation<'_>> {
+        let mut inner = self.inner.lock();
+        let mapping = inner.mapping.as_mut()?;
+        let offset = ptr.checked_sub(mapping.address)?;
+        let (size, odata) = mapping.alloc.reserve_existing(offset).ok()?;
+        let mut alloc = Allocation::new(self, offset, size, ptr, mapping.pages.clone());
+        if let Some(data) = odata {
+            alloc.set_info(data);
+        }
+        Some(alloc)
+    }
+
+    pub(crate) fn buffer_raw_free(&self, ptr: usize) {
+        let mut inner = self.inner.lock();
+        if let Some(ref mut mapping) = &mut inner.mapping {
+            if ptr < mapping.address
+                || mapping
+                    .alloc
+                    .reservation_abort(ptr - mapping.address)
+                    .is_err()
+            {
+                pr_warn!(
+                    "Pointer {:x} failed to free, base = {:x}\n",
+                    ptr,
+                    mapping.address
+                );
+            }
+        }
+    }
+
+    pub(crate) fn buffer_make_freeable(&self, offset: usize, data: Option<AllocationInfo>) {
+        let mut inner = self.inner.lock();
+        if let Some(ref mut mapping) = &mut inner.mapping {
+            if mapping.alloc.reservation_commit(offset, data).is_err() {
+                pr_warn!("Offset {} failed to be marked freeable\n", offset);
+            }
+        }
+    }
+
+    fn create_mapping(&self, vma: &mut mm::virt::Area) -> Result {
+        let size = core::cmp::min(vma.end() - vma.start(), bindings::SZ_4M as usize);
+        let page_count = size / kernel::PAGE_SIZE;
+
+        // Allocate and map all pages.
+        //
+        // N.B. If we fail halfway through mapping these pages, the kernel will unmap them.
+        let mut pages = Vec::new();
+        pages.try_reserve_exact(page_count)?;
+        let mut address = vma.start();
+        for _ in 0..page_count {
+            let page = Pages::<0>::new()?;
+            vma.insert_page(address, &page)?;
+            pages.try_push(page)?;
+            address += kernel::PAGE_SIZE;
+        }
+
+        let ref_pages = Ref::try_from(pages)?;
+
+        // Save pages for later.
+        let mut inner = self.inner.lock();
+        match &inner.mapping {
+            None => inner.mapping = Some(Mapping::new(vma.start(), size, ref_pages)?),
+            Some(_) => return Err(EBUSY),
+        }
+        Ok(())
+    }
+
+    fn version(&self, data: UserSlicePtr) -> Result {
+        data.writer().write(&BinderVersion::current())
+    }
+
+    pub(crate) fn register_thread(&self) -> bool {
+        self.inner.lock().register_thread()
+    }
+
+    fn remove_thread(&self, thread: Ref<Thread>) {
+        self.inner.lock().threads.remove(&thread.id);
+        thread.release();
+    }
+
+    fn set_max_threads(&self, max: u32) {
+        self.inner.lock().max_threads = max;
+    }
+
+    fn get_node_debug_info(&self, data: UserSlicePtr) -> Result {
+        let (mut reader, mut writer) = data.reader_writer();
+
+        // Read the starting point.
+        let ptr = reader.read::<BinderNodeDebugInfo>()?.ptr as usize;
+        let mut out = BinderNodeDebugInfo::default();
+
+        {
+            let inner = self.inner.lock();
+            for (node_ptr, node) in &inner.nodes {
+                if *node_ptr > ptr {
+                    node.populate_debug_info(&mut out, &inner);
+                    break;
+                }
+            }
+        }
+
+        writer.write(&out)
+    }
+
+    fn get_node_info_from_ref(&self, data: UserSlicePtr) -> Result {
+        let (mut reader, mut writer) = data.reader_writer();
+        let mut out = reader.read::<BinderNodeInfoForRef>()?;
+
+        if out.strong_count != 0
+            || out.weak_count != 0
+            || out.reserved1 != 0
+            || out.reserved2 != 0
+            || out.reserved3 != 0
+        {
+            return Err(EINVAL);
+        }
+
+        // Only the context manager is allowed to use this ioctl.
+        if !self.inner.lock().is_manager {
+            return Err(EPERM);
+        }
+
+        let node_ref = self
+            .get_node_from_handle(out.handle, true)
+            .or(Err(EINVAL))?;
+
+        // Get the counts from the node.
+        {
+            let owner_inner = node_ref.node.owner.inner.lock();
+            node_ref.node.populate_counts(&mut out, &owner_inner);
+        }
+
+        // Write the result back.
+        writer.write(&out)
+    }
+
+    pub(crate) fn needs_thread(&self) -> bool {
+        let mut inner = self.inner.lock();
+        let ret = inner.requested_thread_count == 0
+            && inner.ready_threads.is_empty()
+            && inner.started_thread_count < inner.max_threads;
+        if ret {
+            inner.requested_thread_count += 1
+        };
+        ret
+    }
+
+    pub(crate) fn request_death(
+        self: &Ref<Self>,
+        reader: &mut UserSlicePtrReader,
+        thread: &Thread,
+    ) -> Result {
+        let handle: u32 = reader.read()?;
+        let cookie: usize = reader.read()?;
+
+        // TODO: First two should result in error, but not the others.
+
+        // TODO: Do we care about the context manager dying?
+
+        // Queue BR_ERROR if we can't allocate memory for the death notification.
+        let death = UniqueRef::try_new_uninit().map_err(|err| {
+            thread.push_return_work(BR_ERROR);
+            err
+        })?;
+
+        let mut refs = self.node_refs.lock();
+        let info = refs.by_handle.get_mut(&handle).ok_or(EINVAL)?;
+
+        // Nothing to do if there is already a death notification request for this handle.
+        if info.death.is_some() {
+            return Ok(());
+        }
+
+        let death = {
+            let mut pinned = Pin::from(death.write(
+                // SAFETY: `init` is called below.
+                unsafe { NodeDeath::new(info.node_ref.node.clone(), self.clone(), cookie) },
+            ));
+            pinned.as_mut().init();
+            Ref::<NodeDeath>::from(pinned)
+        };
+
+        info.death = Some(death.clone());
+
+        // Register the death notification.
+        {
+            let mut owner_inner = info.node_ref.node.owner.inner.lock();
+            if owner_inner.is_dead {
+                drop(owner_inner);
+                let _ = self.push_work(death);
+            } else {
+                info.node_ref.node.add_death(death, &mut owner_inner);
+            }
+        }
+        Ok(())
+    }
+
+    pub(crate) fn clear_death(&self, reader: &mut UserSlicePtrReader, thread: &Thread) -> Result {
+        let handle: u32 = reader.read()?;
+        let cookie: usize = reader.read()?;
+
+        let mut refs = self.node_refs.lock();
+        let info = refs.by_handle.get_mut(&handle).ok_or(EINVAL)?;
+
+        let death = info.death.take().ok_or(EINVAL)?;
+        if death.cookie != cookie {
+            info.death = Some(death);
+            return Err(EINVAL);
+        }
+
+        // Update state and determine if we need to queue a work item. We only need to do it when
+        // the node is not dead or if the user already completed the death notification.
+        if death.set_cleared(false) {
+            let _ = thread.push_work_if_looper(death);
+        }
+
+        Ok(())
+    }
+
+    pub(crate) fn dead_binder_done(&self, cookie: usize, thread: &Thread) {
+        if let Some(death) = self.inner.lock().pull_delivered_death(cookie) {
+            death.set_notification_done(thread);
+        }
+    }
+}
+
+impl IoctlHandler for Process {
+    type Target<'a> = RefBorrow<'a, Process>;
+
+    fn write(
+        this: RefBorrow<'_, Process>,
+        _file: &File,
+        cmd: u32,
+        reader: &mut UserSlicePtrReader,
+    ) -> Result<i32> {
+        let thread = this.get_thread(Task::current().pid())?;
+        match cmd {
+            bindings::BINDER_SET_MAX_THREADS => this.set_max_threads(reader.read()?),
+            bindings::BINDER_SET_CONTEXT_MGR => this.set_as_manager(None, &thread)?,
+            bindings::BINDER_THREAD_EXIT => this.remove_thread(thread),
+            bindings::BINDER_SET_CONTEXT_MGR_EXT => {
+                this.set_as_manager(Some(reader.read()?), &thread)?
+            }
+            _ => return Err(EINVAL),
+        }
+        Ok(0)
+    }
+
+    fn read_write(
+        this: RefBorrow<'_, Process>,
+        file: &File,
+        cmd: u32,
+        data: UserSlicePtr,
+    ) -> Result<i32> {
+        let thread = this.get_thread(Task::current().pid())?;
+        let blocking = (file.flags() & file::flags::O_NONBLOCK) == 0;
+        match cmd {
+            bindings::BINDER_WRITE_READ => thread.write_read(data, blocking)?,
+            bindings::BINDER_GET_NODE_DEBUG_INFO => this.get_node_debug_info(data)?,
+            bindings::BINDER_GET_NODE_INFO_FOR_REF => this.get_node_info_from_ref(data)?,
+            bindings::BINDER_VERSION => this.version(data)?,
+            _ => return Err(EINVAL),
+        }
+        Ok(0)
+    }
+}
+
+#[vtable]
+impl file::Operations for Process {
+    type Data = Ref<Self>;
+    type OpenData = Ref<Context>;
+
+    fn open(ctx: &Ref<Context>, file: &File) -> Result<Self::Data> {
+        Self::new(ctx.clone(), file.cred().into())
+    }
+
+    fn release(obj: Self::Data, _file: &File) {
+        // Mark this process as dead. We'll do the same for the threads later.
+        obj.inner.lock().is_dead = true;
+
+        // If this process is the manager, unset it.
+        if obj.inner.lock().is_manager {
+            obj.ctx.unset_manager_node();
+        }
+
+        // TODO: Do this in a worker?
+
+        // Cancel all pending work items.
+        while let Some(work) = obj.get_work() {
+            work.cancel();
+        }
+
+        // Free any resources kept alive by allocated buffers.
+        let omapping = obj.inner.lock().mapping.take();
+        if let Some(mut mapping) = omapping {
+            let address = mapping.address;
+            let pages = mapping.pages.clone();
+            mapping.alloc.for_each(|offset, size, odata| {
+                let ptr = offset + address;
+                let mut alloc = Allocation::new(&obj, offset, size, ptr, pages.clone());
+                if let Some(data) = odata {
+                    alloc.set_info(data);
+                }
+                drop(alloc)
+            });
+        }
+
+        // Drop all references. We do this dance with `swap` to avoid destroying the references
+        // while holding the lock.
+        let mut refs = obj.node_refs.lock();
+        let mut node_refs = take(&mut refs.by_handle);
+        drop(refs);
+
+        // Remove all death notifications from the nodes (that belong to a different process).
+        for info in node_refs.values_mut() {
+            let death = if let Some(existing) = info.death.take() {
+                existing
+            } else {
+                continue;
+            };
+
+            death.set_cleared(false);
+        }
+
+        // Do similar dance for the state lock.
+        let mut inner = obj.inner.lock();
+        let threads = take(&mut inner.threads);
+        let nodes = take(&mut inner.nodes);
+        drop(inner);
+
+        // Release all threads.
+        for thread in threads.values() {
+            thread.release();
+        }
+
+        // Deliver death notifications.
+        for node in nodes.values() {
+            loop {
+                let death = {
+                    let mut inner = obj.inner.lock();
+                    if let Some(death) = node.next_death(&mut inner) {
+                        death
+                    } else {
+                        break;
+                    }
+                };
+
+                death.set_dead();
+            }
+        }
+    }
+
+    fn ioctl(this: RefBorrow<'_, Process>, file: &File, cmd: &mut IoctlCommand) -> Result<i32> {
+        cmd.dispatch::<Self>(this, file)
+    }
+
+    fn compat_ioctl(
+        this: RefBorrow<'_, Process>,
+        file: &File,
+        cmd: &mut IoctlCommand,
+    ) -> Result<i32> {
+        cmd.dispatch::<Self>(this, file)
+    }
+
+    fn mmap(this: RefBorrow<'_, Process>, _file: &File, vma: &mut mm::virt::Area) -> Result {
+        // We don't allow mmap to be used in a different process.
+        if !core::ptr::eq(Task::current().group_leader(), &*this.task) {
+            return Err(EINVAL);
+        }
+
+        if vma.start() == 0 {
+            return Err(EINVAL);
+        }
+
+        let mut flags = vma.flags();
+        use mm::virt::flags::*;
+        if flags & WRITE != 0 {
+            return Err(EPERM);
+        }
+
+        flags |= DONTCOPY | MIXEDMAP;
+        flags &= !MAYWRITE;
+        vma.set_flags(flags);
+
+        // TODO: Set ops. We need to learn when the user unmaps so that we can stop using it.
+        this.create_mapping(vma)
+    }
+
+    fn poll(this: RefBorrow<'_, Process>, file: &File, table: &PollTable) -> Result<u32> {
+        let thread = this.get_thread(Task::current().pid())?;
+        let (from_proc, mut mask) = thread.poll(file, table);
+        if mask == 0 && from_proc && !this.inner.lock().work.is_empty() {
+            mask |= bindings::POLLIN;
+        }
+        Ok(mask)
+    }
+}
+
+pub(crate) struct Registration<'a> {
+    process: &'a Process,
+    thread: &'a Ref<Thread>,
+}
+
+impl<'a> Registration<'a> {
+    fn new(
+        process: &'a Process,
+        thread: &'a Ref<Thread>,
+        guard: &mut Guard<'_, Mutex<ProcessInner>>,
+    ) -> Self {
+        guard.ready_threads.push_back(thread.clone());
+        Self { process, thread }
+    }
+}
+
+impl Drop for Registration<'_> {
+    fn drop(&mut self) {
+        let mut inner = self.process.inner.lock();
+        unsafe { inner.ready_threads.remove(self.thread) };
+    }
+}
diff --git a/drivers/android/range_alloc.rs b/drivers/android/range_alloc.rs
new file mode 100644
index 000000000000..7b149048879b
--- /dev/null
+++ b/drivers/android/range_alloc.rs
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::ptr::NonNull;
+use kernel::{
+    linked_list::{CursorMut, GetLinks, Links, List},
+    prelude::*,
+};
+
+pub(crate) struct RangeAllocator<T> {
+    list: List<Box<Descriptor<T>>>,
+}
+
+#[derive(Debug, PartialEq, Eq)]
+enum DescriptorState {
+    Free,
+    Reserved,
+    Allocated,
+}
+
+impl<T> RangeAllocator<T> {
+    pub(crate) fn new(size: usize) -> Result<Self> {
+        let desc = Box::try_new(Descriptor::new(0, size))?;
+        let mut list = List::new();
+        list.push_back(desc);
+        Ok(Self { list })
+    }
+
+    fn find_best_match(&self, size: usize) -> Option<NonNull<Descriptor<T>>> {
+        // TODO: Use a binary tree instead of list for this lookup.
+        let mut best = None;
+        let mut best_size = usize::MAX;
+        let mut cursor = self.list.cursor_front();
+        while let Some(desc) = cursor.current() {
+            if desc.state == DescriptorState::Free {
+                if size == desc.size {
+                    return Some(NonNull::from(desc));
+                }
+
+                if size < desc.size && desc.size < best_size {
+                    best = Some(NonNull::from(desc));
+                    best_size = desc.size;
+                }
+            }
+
+            cursor.move_next();
+        }
+        best
+    }
+
+    pub(crate) fn reserve_new(&mut self, size: usize) -> Result<usize> {
+        let desc_ptr = match self.find_best_match(size) {
+            None => return Err(ENOMEM),
+            Some(found) => found,
+        };
+
+        // SAFETY: We hold the only mutable reference to list, so it cannot have changed.
+        let desc = unsafe { &mut *desc_ptr.as_ptr() };
+        if desc.size == size {
+            desc.state = DescriptorState::Reserved;
+            return Ok(desc.offset);
+        }
+
+        // We need to break up the descriptor.
+        let new = Box::try_new(Descriptor::new(desc.offset + size, desc.size - size))?;
+        unsafe { self.list.insert_after(desc_ptr, new) };
+        desc.state = DescriptorState::Reserved;
+        desc.size = size;
+        Ok(desc.offset)
+    }
+
+    fn free_with_cursor(cursor: &mut CursorMut<'_, Box<Descriptor<T>>>) -> Result {
+        let mut size = match cursor.current() {
+            None => return Err(EINVAL),
+            Some(ref mut entry) => {
+                match entry.state {
+                    DescriptorState::Free => return Err(EINVAL),
+                    DescriptorState::Allocated => return Err(EPERM),
+                    DescriptorState::Reserved => {}
+                }
+                entry.state = DescriptorState::Free;
+                entry.size
+            }
+        };
+
+        // Try to merge with the next entry.
+        if let Some(next) = cursor.peek_next() {
+            if next.state == DescriptorState::Free {
+                next.offset -= size;
+                next.size += size;
+                size = next.size;
+                cursor.remove_current();
+            }
+        }
+
+        // Try to merge with the previous entry.
+        if let Some(prev) = cursor.peek_prev() {
+            if prev.state == DescriptorState::Free {
+                prev.size += size;
+                cursor.remove_current();
+            }
+        }
+
+        Ok(())
+    }
+
+    fn find_at_offset(&mut self, offset: usize) -> Option<CursorMut<'_, Box<Descriptor<T>>>> {
+        let mut cursor = self.list.cursor_front_mut();
+        while let Some(desc) = cursor.current() {
+            if desc.offset == offset {
+                return Some(cursor);
+            }
+
+            if desc.offset > offset {
+                return None;
+            }
+
+            cursor.move_next();
+        }
+        None
+    }
+
+    pub(crate) fn reservation_abort(&mut self, offset: usize) -> Result {
+        // TODO: The force case is currently O(n), but could be made O(1) with unsafe.
+        let mut cursor = self.find_at_offset(offset).ok_or(EINVAL)?;
+        Self::free_with_cursor(&mut cursor)
+    }
+
+    pub(crate) fn reservation_commit(&mut self, offset: usize, data: Option<T>) -> Result {
+        // TODO: This is currently O(n), make it O(1).
+        let mut cursor = self.find_at_offset(offset).ok_or(ENOENT)?;
+        let desc = cursor.current().unwrap();
+        desc.state = DescriptorState::Allocated;
+        desc.data = data;
+        Ok(())
+    }
+
+    /// Takes an entry at the given offset from [`DescriptorState::Allocated`] to
+    /// [`DescriptorState::Reserved`].
+    ///
+    /// Returns the size of the existing entry and the data associated with it.
+    pub(crate) fn reserve_existing(&mut self, offset: usize) -> Result<(usize, Option<T>)> {
+        // TODO: This is currently O(n), make it O(log n).
+        let mut cursor = self.find_at_offset(offset).ok_or(ENOENT)?;
+        let desc = cursor.current().unwrap();
+        if desc.state != DescriptorState::Allocated {
+            return Err(ENOENT);
+        }
+        desc.state = DescriptorState::Reserved;
+        Ok((desc.size, desc.data.take()))
+    }
+
+    pub(crate) fn for_each<F: Fn(usize, usize, Option<T>)>(&mut self, callback: F) {
+        let mut cursor = self.list.cursor_front_mut();
+        while let Some(desc) = cursor.current() {
+            if desc.state == DescriptorState::Allocated {
+                callback(desc.offset, desc.size, desc.data.take());
+            }
+
+            cursor.move_next();
+        }
+    }
+}
+
+struct Descriptor<T> {
+    state: DescriptorState,
+    size: usize,
+    offset: usize,
+    links: Links<Descriptor<T>>,
+    data: Option<T>,
+}
+
+impl<T> Descriptor<T> {
+    fn new(offset: usize, size: usize) -> Self {
+        Self {
+            size,
+            offset,
+            state: DescriptorState::Free,
+            links: Links::new(),
+            data: None,
+        }
+    }
+}
+
+impl<T> GetLinks for Descriptor<T> {
+    type EntryType = Self;
+    fn get_links(desc: &Self) -> &Links<Self> {
+        &desc.links
+    }
+}
diff --git a/drivers/android/rust_binder.rs b/drivers/android/rust_binder.rs
new file mode 100644
index 000000000000..6305a3045911
--- /dev/null
+++ b/drivers/android/rust_binder.rs
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Binder -- the Android IPC mechanism.
+//!
+//! TODO: This module is a work in progress.
+
+use kernel::{
+    io_buffer::IoBufferWriter,
+    linked_list::{GetLinks, GetLinksWrapped, Links},
+    miscdev::Registration,
+    prelude::*,
+    str::CStr,
+    sync::Ref,
+    user_ptr::UserSlicePtrWriter,
+};
+
+mod allocation;
+mod context;
+mod defs;
+mod node;
+mod process;
+mod range_alloc;
+mod thread;
+mod transaction;
+
+use {context::Context, thread::Thread};
+
+module! {
+    type: BinderModule,
+    name: b"rust_binder",
+    author: b"Wedson Almeida Filho",
+    description: b"Android Binder",
+    license: b"GPL",
+}
+
+trait DeliverToRead {
+    /// Performs work. Returns true if remaining work items in the queue should be processed
+    /// immediately, or false if it should return to caller before processing additional work
+    /// items.
+    fn do_work(self: Ref<Self>, thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool>;
+
+    /// Cancels the given work item. This is called instead of [`DeliverToRead::do_work`] when work
+    /// won't be delivered.
+    fn cancel(self: Ref<Self>) {}
+
+    /// Returns the linked list links for the work item.
+    fn get_links(&self) -> &Links<dyn DeliverToRead>;
+}
+
+struct DeliverToReadListAdapter {}
+
+impl GetLinks for DeliverToReadListAdapter {
+    type EntryType = dyn DeliverToRead;
+
+    fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+        data.get_links()
+    }
+}
+
+impl GetLinksWrapped for DeliverToReadListAdapter {
+    type Wrapped = Ref<dyn DeliverToRead>;
+}
+
+struct DeliverCode {
+    code: u32,
+    links: Links<dyn DeliverToRead>,
+}
+
+impl DeliverCode {
+    fn new(code: u32) -> Self {
+        Self {
+            code,
+            links: Links::new(),
+        }
+    }
+}
+
+impl DeliverToRead for DeliverCode {
+    fn do_work(self: Ref<Self>, _thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+        writer.write(&self.code)?;
+        Ok(true)
+    }
+
+    fn get_links(&self) -> &Links<dyn DeliverToRead> {
+        &self.links
+    }
+}
+
+const fn ptr_align(value: usize) -> usize {
+    let size = core::mem::size_of::<usize>() - 1;
+    (value + size) & !size
+}
+
+unsafe impl Sync for BinderModule {}
+
+struct BinderModule {
+    _reg: Pin<Box<Registration<process::Process>>>,
+}
+
+impl kernel::Module for BinderModule {
+    fn init(name: &'static CStr, _module: &'static kernel::ThisModule) -> Result<Self> {
+        let ctx = Context::new()?;
+        let reg = Registration::new_pinned(fmt!("{name}"), ctx)?;
+        Ok(Self { _reg: reg })
+    }
+}
diff --git a/drivers/android/thread.rs b/drivers/android/thread.rs
new file mode 100644
index 000000000000..105a65cec1d4
--- /dev/null
+++ b/drivers/android/thread.rs
@@ -0,0 +1,871 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::{
+    alloc::AllocError,
+    mem::size_of,
+    sync::atomic::{AtomicU32, Ordering},
+};
+use kernel::{
+    bindings,
+    file::{File, PollTable},
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    linked_list::{GetLinks, Links, List},
+    prelude::*,
+    security,
+    sync::{CondVar, Ref, SpinLock, UniqueRef},
+    user_ptr::{UserSlicePtr, UserSlicePtrWriter},
+    Either,
+};
+
+use crate::{
+    allocation::{Allocation, AllocationView},
+    defs::*,
+    process::{AllocationInfo, Process},
+    ptr_align,
+    transaction::{FileInfo, Transaction},
+    DeliverCode, DeliverToRead, DeliverToReadListAdapter,
+};
+
+pub(crate) type BinderResult<T = ()> = core::result::Result<T, BinderError>;
+
+pub(crate) struct BinderError {
+    pub(crate) reply: u32,
+}
+
+impl BinderError {
+    pub(crate) fn new_failed() -> Self {
+        Self {
+            reply: BR_FAILED_REPLY,
+        }
+    }
+
+    pub(crate) fn new_dead() -> Self {
+        Self {
+            reply: BR_DEAD_REPLY,
+        }
+    }
+}
+
+impl From<Error> for BinderError {
+    fn from(_: Error) -> Self {
+        Self::new_failed()
+    }
+}
+
+impl From<AllocError> for BinderError {
+    fn from(_: AllocError) -> Self {
+        Self::new_failed()
+    }
+}
+
+const LOOPER_REGISTERED: u32 = 0x01;
+const LOOPER_ENTERED: u32 = 0x02;
+const LOOPER_EXITED: u32 = 0x04;
+const LOOPER_INVALID: u32 = 0x08;
+const LOOPER_WAITING: u32 = 0x10;
+const LOOPER_POLL: u32 = 0x20;
+
+struct InnerThread {
+    /// Determines the looper state of the thread. It is a bit-wise combination of the constants
+    /// prefixed with `LOOPER_`.
+    looper_flags: u32,
+
+    /// Determines if thread is dead.
+    is_dead: bool,
+
+    /// Work item used to deliver error codes to the thread that started a transaction. When set to
+    /// `Some(x)`, it will hold the only reference to the object so that it can update the error
+    /// code to be delivered before queuing it.
+    reply_work: Option<Ref<ThreadError>>,
+
+    /// Work item used to deliver error codes to the current thread. When set to `Some(x)`, it will
+    /// hold the only reference to the object so that it can update the error code to be delivered
+    /// before queuing.
+    return_work: Option<Ref<ThreadError>>,
+
+    /// Determines whether the work list below should be processed. When set to false, `work_list`
+    /// is treated as if it were empty.
+    process_work_list: bool,
+    work_list: List<DeliverToReadListAdapter>,
+    current_transaction: Option<Ref<Transaction>>,
+}
+
+impl InnerThread {
+    fn new() -> Self {
+        Self {
+            looper_flags: 0,
+            is_dead: false,
+            process_work_list: false,
+            work_list: List::new(),
+            current_transaction: None,
+            return_work: None,
+            reply_work: None,
+        }
+    }
+
+    fn set_reply_work(&mut self, reply_work: Ref<ThreadError>) {
+        self.reply_work = Some(reply_work);
+    }
+
+    fn push_reply_work(&mut self, code: u32) {
+        let work = self.reply_work.take();
+        self.push_existing_work(work, code);
+    }
+
+    fn set_return_work(&mut self, return_work: Ref<ThreadError>) {
+        self.return_work = Some(return_work);
+    }
+
+    fn push_return_work(&mut self, code: u32) {
+        let work = self.return_work.take();
+        self.push_existing_work(work, code);
+    }
+
+    fn push_existing_work(&mut self, owork: Option<Ref<ThreadError>>, code: u32) {
+        // TODO: Write some warning when the following fails. It should not happen, and
+        // if it does, there is likely something wrong.
+        if let Some(work) = owork {
+            // `error_code` is written to with relaxed semantics because the queue onto which it is
+            // being inserted is protected by a lock. The release barrier when the lock is released
+            // by the caller matches with the acquire barrier of the future reader to guarantee
+            // that `error_code` is visible.
+            work.error_code.store(code, Ordering::Relaxed);
+            self.push_work(work);
+        }
+    }
+
+    fn pop_work(&mut self) -> Option<Ref<dyn DeliverToRead>> {
+        if !self.process_work_list {
+            return None;
+        }
+
+        let ret = self.work_list.pop_front();
+        // Once the queue is drained, we stop processing it until a non-deferred item is pushed
+        // again onto it.
+        self.process_work_list = !self.work_list.is_empty();
+        ret
+    }
+
+    fn push_work_deferred(&mut self, work: Ref<dyn DeliverToRead>) {
+        self.work_list.push_back(work);
+    }
+
+    fn push_work(&mut self, work: Ref<dyn DeliverToRead>) {
+        self.push_work_deferred(work);
+        self.process_work_list = true;
+    }
+
+    fn has_work(&self) -> bool {
+        self.process_work_list && !self.work_list.is_empty()
+    }
+
+    /// Fetches the transaction the thread can reply to. If the thread has a pending transaction
+    /// (that it could respond to) but it has also issued a transaction, it must first wait for the
+    /// previously-issued transaction to complete.
+    fn pop_transaction_to_reply(&mut self, thread: &Thread) -> Result<Ref<Transaction>> {
+        let transaction = self.current_transaction.take().ok_or(EINVAL)?;
+
+        if core::ptr::eq(thread, transaction.from.as_ref()) {
+            self.current_transaction = Some(transaction);
+            return Err(EINVAL);
+        }
+
+        // Find a new current transaction for this thread.
+        self.current_transaction = transaction.find_from(thread);
+        Ok(transaction)
+    }
+
+    fn pop_transaction_replied(&mut self, transaction: &Ref<Transaction>) -> bool {
+        match self.current_transaction.take() {
+            None => false,
+            Some(old) => {
+                if !Ref::ptr_eq(transaction, &old) {
+                    self.current_transaction = Some(old);
+                    return false;
+                }
+                self.current_transaction = old.clone_next();
+                true
+            }
+        }
+    }
+
+    fn looper_enter(&mut self) {
+        self.looper_flags |= LOOPER_ENTERED;
+        if self.looper_flags & LOOPER_REGISTERED != 0 {
+            self.looper_flags |= LOOPER_INVALID;
+        }
+    }
+
+    fn looper_register(&mut self, valid: bool) {
+        self.looper_flags |= LOOPER_REGISTERED;
+        if !valid || self.looper_flags & LOOPER_ENTERED != 0 {
+            self.looper_flags |= LOOPER_INVALID;
+        }
+    }
+
+    fn looper_exit(&mut self) {
+        self.looper_flags |= LOOPER_EXITED;
+    }
+
+    /// Determines whether the thread is part of a pool, i.e., if it is a looper.
+    fn is_looper(&self) -> bool {
+        self.looper_flags & (LOOPER_ENTERED | LOOPER_REGISTERED) != 0
+    }
+
+    /// Determines whether the thread should attempt to fetch work items from the process queue
+    /// (when its own queue is empty). This is case when the thread is not part of a transaction
+    /// stack and it is registered as a looper.
+    fn should_use_process_work_queue(&self) -> bool {
+        self.current_transaction.is_none() && self.is_looper()
+    }
+
+    fn poll(&mut self) -> u32 {
+        self.looper_flags |= LOOPER_POLL;
+        if self.has_work() {
+            bindings::POLLIN
+        } else {
+            0
+        }
+    }
+}
+
+pub(crate) struct Thread {
+    pub(crate) id: i32,
+    pub(crate) process: Ref<Process>,
+    inner: SpinLock<InnerThread>,
+    work_condvar: CondVar,
+    links: Links<Thread>,
+}
+
+impl Thread {
+    pub(crate) fn new(id: i32, process: Ref<Process>) -> Result<Ref<Self>> {
+        let return_work = Ref::try_new(ThreadError::new(InnerThread::set_return_work))?;
+        let reply_work = Ref::try_new(ThreadError::new(InnerThread::set_reply_work))?;
+        let mut thread = Pin::from(UniqueRef::try_new(Self {
+            id,
+            process,
+            // SAFETY: `inner` is initialised in the call to `spinlock_init` below.
+            inner: unsafe { SpinLock::new(InnerThread::new()) },
+            // SAFETY: `work_condvar` is initialised in the call to `condvar_init` below.
+            work_condvar: unsafe { CondVar::new() },
+            links: Links::new(),
+        })?);
+
+        // SAFETY: `inner` is pinned when `thread` is.
+        let inner = unsafe { thread.as_mut().map_unchecked_mut(|t| &mut t.inner) };
+        kernel::spinlock_init!(inner, "Thread::inner");
+
+        // SAFETY: `work_condvar` is pinned when `thread` is.
+        let condvar = unsafe { thread.as_mut().map_unchecked_mut(|t| &mut t.work_condvar) };
+        kernel::condvar_init!(condvar, "Thread::work_condvar");
+
+        {
+            let mut inner = thread.inner.lock();
+            inner.set_reply_work(reply_work);
+            inner.set_return_work(return_work);
+        }
+
+        Ok(thread.into())
+    }
+
+    pub(crate) fn set_current_transaction(&self, transaction: Ref<Transaction>) {
+        self.inner.lock().current_transaction = Some(transaction);
+    }
+
+    /// Attempts to fetch a work item from the thread-local queue. The behaviour if the queue is
+    /// empty depends on `wait`: if it is true, the function waits for some work to be queued (or a
+    /// signal); otherwise it returns indicating that none is available.
+    fn get_work_local(self: &Ref<Self>, wait: bool) -> Result<Ref<dyn DeliverToRead>> {
+        // Try once if the caller does not want to wait.
+        if !wait {
+            return self.inner.lock().pop_work().ok_or(EAGAIN);
+        }
+
+        // Loop waiting only on the local queue (i.e., not registering with the process queue).
+        let mut inner = self.inner.lock();
+        loop {
+            if let Some(work) = inner.pop_work() {
+                return Ok(work);
+            }
+
+            inner.looper_flags |= LOOPER_WAITING;
+            let signal_pending = self.work_condvar.wait(&mut inner);
+            inner.looper_flags &= !LOOPER_WAITING;
+
+            if signal_pending {
+                return Err(ERESTARTSYS);
+            }
+        }
+    }
+
+    /// Attempts to fetch a work item from the thread-local queue, falling back to the process-wide
+    /// queue if none is available locally.
+    ///
+    /// This must only be called when the thread is not participating in a transaction chain. If it
+    /// is, the local version (`get_work_local`) should be used instead.
+    fn get_work(self: &Ref<Self>, wait: bool) -> Result<Ref<dyn DeliverToRead>> {
+        // Try to get work from the thread's work queue, using only a local lock.
+        {
+            let mut inner = self.inner.lock();
+            if let Some(work) = inner.pop_work() {
+                return Ok(work);
+            }
+        }
+
+        // If the caller doesn't want to wait, try to grab work from the process queue.
+        //
+        // We know nothing will have been queued directly to the thread queue because it is not in
+        // a transaction and it is not in the process' ready list.
+        if !wait {
+            return self.process.get_work().ok_or(EAGAIN);
+        }
+
+        // Get work from the process queue. If none is available, atomically register as ready.
+        let reg = match self.process.get_work_or_register(self) {
+            Either::Left(work) => return Ok(work),
+            Either::Right(reg) => reg,
+        };
+
+        let mut inner = self.inner.lock();
+        loop {
+            if let Some(work) = inner.pop_work() {
+                return Ok(work);
+            }
+
+            inner.looper_flags |= LOOPER_WAITING;
+            let signal_pending = self.work_condvar.wait(&mut inner);
+            inner.looper_flags &= !LOOPER_WAITING;
+
+            if signal_pending {
+                // A signal is pending. We need to pull the thread off the list, then check the
+                // state again after it's off the list to ensure that something was not queued in
+                // the meantime. If something has been queued, we just return it (instead of the
+                // error).
+                drop(inner);
+                drop(reg);
+                return self.inner.lock().pop_work().ok_or(ERESTARTSYS);
+            }
+        }
+    }
+
+    pub(crate) fn push_work(&self, work: Ref<dyn DeliverToRead>) -> BinderResult {
+        {
+            let mut inner = self.inner.lock();
+            if inner.is_dead {
+                return Err(BinderError::new_dead());
+            }
+            inner.push_work(work);
+        }
+        self.work_condvar.notify_one();
+        Ok(())
+    }
+
+    /// Attempts to push to given work item to the thread if it's a looper thread (i.e., if it's
+    /// part of a thread pool) and is alive. Otherwise, push the work item to the process instead.
+    pub(crate) fn push_work_if_looper(&self, work: Ref<dyn DeliverToRead>) -> BinderResult {
+        let mut inner = self.inner.lock();
+        if inner.is_looper() && !inner.is_dead {
+            inner.push_work(work);
+            Ok(())
+        } else {
+            drop(inner);
+            self.process.push_work(work)
+        }
+    }
+
+    pub(crate) fn push_work_deferred(&self, work: Ref<dyn DeliverToRead>) {
+        self.inner.lock().push_work_deferred(work);
+    }
+
+    fn translate_object(
+        &self,
+        index_offset: usize,
+        view: &mut AllocationView<'_, '_>,
+        allow_fds: bool,
+    ) -> BinderResult {
+        let offset = view.alloc.read(index_offset)?;
+        let header = view.read::<bindings::binder_object_header>(offset)?;
+        // TODO: Handle other types.
+        match header.type_ {
+            BINDER_TYPE_WEAK_BINDER | BINDER_TYPE_BINDER => {
+                let strong = header.type_ == BINDER_TYPE_BINDER;
+                view.transfer_binder_object(offset, strong, |obj| {
+                    // SAFETY: `binder` is a `binder_uintptr_t`; any bit pattern is a valid
+                    // representation.
+                    let ptr = unsafe { obj.__bindgen_anon_1.binder } as _;
+                    let cookie = obj.cookie as _;
+                    let flags = obj.flags as _;
+                    let node = self.process.as_ref_borrow().get_node(
+                        ptr,
+                        cookie,
+                        flags,
+                        strong,
+                        Some(self),
+                    )?;
+                    security::binder_transfer_binder(&self.process.cred, &view.alloc.process.cred)?;
+                    Ok(node)
+                })?;
+            }
+            BINDER_TYPE_WEAK_HANDLE | BINDER_TYPE_HANDLE => {
+                let strong = header.type_ == BINDER_TYPE_HANDLE;
+                view.transfer_binder_object(offset, strong, |obj| {
+                    // SAFETY: `handle` is a `u32`; any bit pattern is a valid representation.
+                    let handle = unsafe { obj.__bindgen_anon_1.handle } as _;
+                    let node = self.process.get_node_from_handle(handle, strong)?;
+                    security::binder_transfer_binder(&self.process.cred, &view.alloc.process.cred)?;
+                    Ok(node)
+                })?;
+            }
+            BINDER_TYPE_FD => {
+                if !allow_fds {
+                    return Err(BinderError::new_failed());
+                }
+
+                let obj = view.read::<bindings::binder_fd_object>(offset)?;
+                // SAFETY: `fd` is a `u32`; any bit pattern is a valid representation.
+                let fd = unsafe { obj.__bindgen_anon_1.fd };
+                let file = File::from_fd(fd)?;
+                security::binder_transfer_file(
+                    &self.process.cred,
+                    &view.alloc.process.cred,
+                    &file,
+                )?;
+                let field_offset =
+                    kernel::offset_of!(bindings::binder_fd_object, __bindgen_anon_1.fd) as usize;
+                let file_info = Box::try_new(FileInfo::new(file, offset + field_offset))?;
+                view.alloc.add_file_info(file_info);
+            }
+            _ => pr_warn!("Unsupported binder object type: {:x}\n", header.type_),
+        }
+        Ok(())
+    }
+
+    fn translate_objects(
+        &self,
+        alloc: &mut Allocation<'_>,
+        start: usize,
+        end: usize,
+        allow_fds: bool,
+    ) -> BinderResult {
+        let mut view = AllocationView::new(alloc, start);
+        for i in (start..end).step_by(size_of::<usize>()) {
+            if let Err(err) = self.translate_object(i, &mut view, allow_fds) {
+                alloc.set_info(AllocationInfo { offsets: start..i });
+                return Err(err);
+            }
+        }
+        alloc.set_info(AllocationInfo {
+            offsets: start..end,
+        });
+        Ok(())
+    }
+
+    pub(crate) fn copy_transaction_data<'a>(
+        &self,
+        to_process: &'a Process,
+        tr: &BinderTransactionData,
+        allow_fds: bool,
+    ) -> BinderResult<Allocation<'a>> {
+        let data_size = tr.data_size as _;
+        let adata_size = ptr_align(data_size);
+        let offsets_size = tr.offsets_size as _;
+        let aoffsets_size = ptr_align(offsets_size);
+
+        // This guarantees that at least `sizeof(usize)` bytes will be allocated.
+        let len = core::cmp::max(
+            adata_size.checked_add(aoffsets_size).ok_or(ENOMEM)?,
+            size_of::<usize>(),
+        );
+        let mut alloc = to_process.buffer_alloc(len)?;
+
+        // Copy raw data.
+        let mut reader = unsafe { UserSlicePtr::new(tr.data.ptr.buffer as _, data_size) }.reader();
+        alloc.copy_into(&mut reader, 0, data_size)?;
+
+        // Copy offsets if there are any.
+        if offsets_size > 0 {
+            let mut reader =
+                unsafe { UserSlicePtr::new(tr.data.ptr.offsets as _, offsets_size) }.reader();
+            alloc.copy_into(&mut reader, adata_size, offsets_size)?;
+
+            // Traverse the objects specified.
+            self.translate_objects(
+                &mut alloc,
+                adata_size,
+                adata_size + aoffsets_size,
+                allow_fds,
+            )?;
+        }
+
+        Ok(alloc)
+    }
+
+    fn unwind_transaction_stack(self: &Ref<Self>) {
+        let mut thread = self.clone();
+        while let Ok(transaction) = {
+            let mut inner = thread.inner.lock();
+            inner.pop_transaction_to_reply(thread.as_ref())
+        } {
+            let reply = Either::Right(BR_DEAD_REPLY);
+            if !transaction.from.deliver_single_reply(reply, &transaction) {
+                break;
+            }
+
+            thread = transaction.from.clone();
+        }
+    }
+
+    pub(crate) fn deliver_reply(
+        &self,
+        reply: Either<Ref<Transaction>, u32>,
+        transaction: &Ref<Transaction>,
+    ) {
+        if self.deliver_single_reply(reply, transaction) {
+            transaction.from.unwind_transaction_stack();
+        }
+    }
+
+    /// Delivers a reply to the thread that started a transaction. The reply can either be a
+    /// reply-transaction or an error code to be delivered instead.
+    ///
+    /// Returns whether the thread is dead. If it is, the caller is expected to unwind the
+    /// transaction stack by completing transactions for threads that are dead.
+    fn deliver_single_reply(
+        &self,
+        reply: Either<Ref<Transaction>, u32>,
+        transaction: &Ref<Transaction>,
+    ) -> bool {
+        {
+            let mut inner = self.inner.lock();
+            if !inner.pop_transaction_replied(transaction) {
+                return false;
+            }
+
+            if inner.is_dead {
+                return true;
+            }
+
+            match reply {
+                Either::Left(work) => inner.push_work(work),
+                Either::Right(code) => inner.push_reply_work(code),
+            }
+        }
+
+        // Notify the thread now that we've released the inner lock.
+        self.work_condvar.notify_one();
+        false
+    }
+
+    /// Determines if the given transaction is the current transaction for this thread.
+    fn is_current_transaction(&self, transaction: &Ref<Transaction>) -> bool {
+        let inner = self.inner.lock();
+        match &inner.current_transaction {
+            None => false,
+            Some(current) => Ref::ptr_eq(current, transaction),
+        }
+    }
+
+    fn transaction<T>(self: &Ref<Self>, tr: &BinderTransactionData, inner: T)
+    where
+        T: FnOnce(&Ref<Self>, &BinderTransactionData) -> BinderResult,
+    {
+        if let Err(err) = inner(self, tr) {
+            self.inner.lock().push_return_work(err.reply);
+        }
+    }
+
+    fn reply_inner(self: &Ref<Self>, tr: &BinderTransactionData) -> BinderResult {
+        let orig = self.inner.lock().pop_transaction_to_reply(self)?;
+        if !orig.from.is_current_transaction(&orig) {
+            return Err(BinderError::new_failed());
+        }
+
+        // We need to complete the transaction even if we cannot complete building the reply.
+        (|| -> BinderResult<_> {
+            let completion = Ref::try_new(DeliverCode::new(BR_TRANSACTION_COMPLETE))?;
+            let process = orig.from.process.clone();
+            let allow_fds = orig.flags & TF_ACCEPT_FDS != 0;
+            let reply = Transaction::new_reply(self, process, tr, allow_fds)?;
+            self.inner.lock().push_work(completion);
+            orig.from.deliver_reply(Either::Left(reply), &orig);
+            Ok(())
+        })()
+        .map_err(|mut err| {
+            // At this point we only return `BR_TRANSACTION_COMPLETE` to the caller, and we must let
+            // the sender know that the transaction has completed (with an error in this case).
+            let reply = Either::Right(BR_FAILED_REPLY);
+            orig.from.deliver_reply(reply, &orig);
+            err.reply = BR_TRANSACTION_COMPLETE;
+            err
+        })
+    }
+
+    /// Determines the current top of the transaction stack. It fails if the top is in another
+    /// thread (i.e., this thread belongs to a stack but it has called another thread). The top is
+    /// [`None`] if the thread is not currently participating in a transaction stack.
+    fn top_of_transaction_stack(&self) -> Result<Option<Ref<Transaction>>> {
+        let inner = self.inner.lock();
+        Ok(if let Some(cur) = &inner.current_transaction {
+            if core::ptr::eq(self, cur.from.as_ref()) {
+                return Err(EINVAL);
+            }
+            Some(cur.clone())
+        } else {
+            None
+        })
+    }
+
+    fn oneway_transaction_inner(self: &Ref<Self>, tr: &BinderTransactionData) -> BinderResult {
+        let handle = unsafe { tr.target.handle };
+        let node_ref = self.process.get_transaction_node(handle)?;
+        security::binder_transaction(&self.process.cred, &node_ref.node.owner.cred)?;
+        let completion = Ref::try_new(DeliverCode::new(BR_TRANSACTION_COMPLETE))?;
+        let transaction = Transaction::new(node_ref, None, self, tr)?;
+        self.inner.lock().push_work(completion);
+        // TODO: Remove the completion on error?
+        transaction.submit()?;
+        Ok(())
+    }
+
+    fn transaction_inner(self: &Ref<Self>, tr: &BinderTransactionData) -> BinderResult {
+        let handle = unsafe { tr.target.handle };
+        let node_ref = self.process.get_transaction_node(handle)?;
+        security::binder_transaction(&self.process.cred, &node_ref.node.owner.cred)?;
+        // TODO: We need to ensure that there isn't a pending transaction in the work queue. How
+        // could this happen?
+        let top = self.top_of_transaction_stack()?;
+        let completion = Ref::try_new(DeliverCode::new(BR_TRANSACTION_COMPLETE))?;
+        let transaction = Transaction::new(node_ref, top, self, tr)?;
+
+        // Check that the transaction stack hasn't changed while the lock was released, then update
+        // it with the new transaction.
+        {
+            let mut inner = self.inner.lock();
+            if !transaction.is_stacked_on(&inner.current_transaction) {
+                return Err(BinderError::new_failed());
+            }
+            inner.current_transaction = Some(transaction.clone());
+        }
+
+        // We push the completion as a deferred work so that we wait for the reply before returning
+        // to userland.
+        self.push_work_deferred(completion);
+        // TODO: Remove completion if submission fails?
+        transaction.submit()?;
+        Ok(())
+    }
+
+    fn write(self: &Ref<Self>, req: &mut BinderWriteRead) -> Result {
+        let write_start = req.write_buffer.wrapping_add(req.write_consumed);
+        let write_len = req.write_size - req.write_consumed;
+        let mut reader = unsafe { UserSlicePtr::new(write_start as _, write_len as _).reader() };
+
+        while reader.len() >= size_of::<u32>() && self.inner.lock().return_work.is_some() {
+            let before = reader.len();
+            match reader.read::<u32>()? {
+                BC_TRANSACTION => {
+                    let tr = reader.read::<BinderTransactionData>()?;
+                    if tr.flags & TF_ONE_WAY != 0 {
+                        self.transaction(&tr, Self::oneway_transaction_inner)
+                    } else {
+                        self.transaction(&tr, Self::transaction_inner)
+                    }
+                }
+                BC_REPLY => self.transaction(&reader.read()?, Self::reply_inner),
+                BC_FREE_BUFFER => drop(self.process.buffer_get(reader.read()?)),
+                BC_INCREFS => self.process.update_ref(reader.read()?, true, false)?,
+                BC_ACQUIRE => self.process.update_ref(reader.read()?, true, true)?,
+                BC_RELEASE => self.process.update_ref(reader.read()?, false, true)?,
+                BC_DECREFS => self.process.update_ref(reader.read()?, false, false)?,
+                BC_INCREFS_DONE => self.process.inc_ref_done(&mut reader, false)?,
+                BC_ACQUIRE_DONE => self.process.inc_ref_done(&mut reader, true)?,
+                BC_REQUEST_DEATH_NOTIFICATION => self.process.request_death(&mut reader, self)?,
+                BC_CLEAR_DEATH_NOTIFICATION => self.process.clear_death(&mut reader, self)?,
+                BC_DEAD_BINDER_DONE => self.process.dead_binder_done(reader.read()?, self),
+                BC_REGISTER_LOOPER => {
+                    let valid = self.process.register_thread();
+                    self.inner.lock().looper_register(valid);
+                }
+                BC_ENTER_LOOPER => self.inner.lock().looper_enter(),
+                BC_EXIT_LOOPER => self.inner.lock().looper_exit(),
+
+                // TODO: Add support for BC_TRANSACTION_SG and BC_REPLY_SG.
+                // BC_ATTEMPT_ACQUIRE and BC_ACQUIRE_RESULT are no longer supported.
+                _ => return Err(EINVAL),
+            }
+
+            // Update the number of write bytes consumed.
+            req.write_consumed += (before - reader.len()) as u64;
+        }
+        Ok(())
+    }
+
+    fn read(self: &Ref<Self>, req: &mut BinderWriteRead, wait: bool) -> Result {
+        let read_start = req.read_buffer.wrapping_add(req.read_consumed);
+        let read_len = req.read_size - req.read_consumed;
+        let mut writer = unsafe { UserSlicePtr::new(read_start as _, read_len as _) }.writer();
+        let (in_pool, getter) = {
+            let inner = self.inner.lock();
+            (
+                inner.is_looper(),
+                if inner.should_use_process_work_queue() {
+                    Self::get_work
+                } else {
+                    Self::get_work_local
+                },
+            )
+        };
+
+        // Reserve some room at the beginning of the read buffer so that we can send a
+        // BR_SPAWN_LOOPER if we need to.
+        if req.read_consumed == 0 {
+            writer.write(&BR_NOOP)?;
+        }
+
+        // Loop doing work while there is room in the buffer.
+        let initial_len = writer.len();
+        while writer.len() >= size_of::<u32>() {
+            match getter(self, wait && initial_len == writer.len()) {
+                Ok(work) => {
+                    if !work.do_work(self, &mut writer)? {
+                        break;
+                    }
+                }
+                Err(err) => {
+                    // Propagate the error if we haven't written anything else.
+                    if initial_len == writer.len() {
+                        return Err(err);
+                    } else {
+                        break;
+                    }
+                }
+            }
+        }
+
+        req.read_consumed += read_len - writer.len() as u64;
+
+        // Write BR_SPAWN_LOOPER if the process needs more threads for its pool.
+        if in_pool && self.process.needs_thread() {
+            let mut writer =
+                unsafe { UserSlicePtr::new(req.read_buffer as _, req.read_size as _) }.writer();
+            writer.write(&BR_SPAWN_LOOPER)?;
+        }
+
+        Ok(())
+    }
+
+    pub(crate) fn write_read(self: &Ref<Self>, data: UserSlicePtr, wait: bool) -> Result {
+        let (mut reader, mut writer) = data.reader_writer();
+        let mut req = reader.read::<BinderWriteRead>()?;
+
+        // TODO: `write(&req)` happens in all exit paths from here on. Find a better way to encode
+        // it.
+
+        // Go through the write buffer.
+        if req.write_size > 0 {
+            if let Err(err) = self.write(&mut req) {
+                req.read_consumed = 0;
+                writer.write(&req)?;
+                return Err(err);
+            }
+        }
+
+        // Go through the work queue.
+        let mut ret = Ok(());
+        if req.read_size > 0 {
+            ret = self.read(&mut req, wait);
+        }
+
+        // Write the request back so that the consumed fields are visible to the caller.
+        writer.write(&req)?;
+        ret
+    }
+
+    pub(crate) fn poll(&self, file: &File, table: &PollTable) -> (bool, u32) {
+        // SAFETY: `free_waiters` is called on release.
+        unsafe { table.register_wait(file, &self.work_condvar) };
+        let mut inner = self.inner.lock();
+        (inner.should_use_process_work_queue(), inner.poll())
+    }
+
+    pub(crate) fn notify_if_poll_ready(&self) {
+        // Determine if we need to notify. This requires the lock.
+        let inner = self.inner.lock();
+        let notify = inner.looper_flags & LOOPER_POLL != 0
+            && inner.should_use_process_work_queue()
+            && !inner.has_work();
+        drop(inner);
+
+        // Now that the lock is no longer held, notify the waiters if we have to.
+        if notify {
+            self.work_condvar.notify_one();
+        }
+    }
+
+    pub(crate) fn push_return_work(&self, code: u32) {
+        self.inner.lock().push_return_work(code)
+    }
+
+    pub(crate) fn release(self: &Ref<Self>) {
+        // Mark the thread as dead.
+        self.inner.lock().is_dead = true;
+
+        // Cancel all pending work items.
+        while let Ok(work) = self.get_work_local(false) {
+            work.cancel();
+        }
+
+        // Complete the transaction stack as far as we can.
+        self.unwind_transaction_stack();
+
+        // Remove epoll items if polling was ever used on the thread.
+        let poller = self.inner.lock().looper_flags & LOOPER_POLL != 0;
+        if poller {
+            self.work_condvar.free_waiters();
+
+            unsafe { bindings::synchronize_rcu() };
+        }
+    }
+}
+
+impl GetLinks for Thread {
+    type EntryType = Thread;
+    fn get_links(data: &Thread) -> &Links<Thread> {
+        &data.links
+    }
+}
+
+struct ThreadError {
+    error_code: AtomicU32,
+    return_fn: fn(&mut InnerThread, Ref<ThreadError>),
+    links: Links<dyn DeliverToRead>,
+}
+
+impl ThreadError {
+    fn new(return_fn: fn(&mut InnerThread, Ref<ThreadError>)) -> Self {
+        Self {
+            error_code: AtomicU32::new(BR_OK),
+            return_fn,
+            links: Links::new(),
+        }
+    }
+}
+
+impl DeliverToRead for ThreadError {
+    fn do_work(self: Ref<Self>, thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+        // See `ThreadInner::push_existing_work` for the reason why `error_code` is up to date even
+        // though we use relaxed semantics.
+        let code = self.error_code.load(Ordering::Relaxed);
+
+        // Return the `ThreadError` to the thread.
+        (self.return_fn)(&mut *thread.inner.lock(), self);
+
+        // Deliver the error code to userspace.
+        writer.write(&code)?;
+        Ok(true)
+    }
+
+    fn get_links(&self) -> &Links<dyn DeliverToRead> {
+        &self.links
+    }
+}
diff --git a/drivers/android/transaction.rs b/drivers/android/transaction.rs
new file mode 100644
index 000000000000..6d8510e3f889
--- /dev/null
+++ b/drivers/android/transaction.rs
@@ -0,0 +1,326 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use core::sync::atomic::{AtomicBool, Ordering};
+use kernel::{
+    bindings,
+    file::{File, FileDescriptorReservation},
+    io_buffer::IoBufferWriter,
+    linked_list::List,
+    linked_list::{GetLinks, Links},
+    prelude::*,
+    sync::{Ref, SpinLock, UniqueRef},
+    user_ptr::UserSlicePtrWriter,
+    Either, ScopeGuard,
+};
+
+use crate::{
+    defs::*,
+    node::NodeRef,
+    process::Process,
+    ptr_align,
+    thread::{BinderResult, Thread},
+    DeliverToRead,
+};
+
+struct TransactionInner {
+    file_list: List<Box<FileInfo>>,
+}
+
+pub(crate) struct Transaction {
+    inner: SpinLock<TransactionInner>,
+    // TODO: Node should be released when the buffer is released.
+    node_ref: Option<NodeRef>,
+    stack_next: Option<Ref<Transaction>>,
+    pub(crate) from: Ref<Thread>,
+    to: Ref<Process>,
+    free_allocation: AtomicBool,
+    code: u32,
+    pub(crate) flags: u32,
+    data_size: usize,
+    offsets_size: usize,
+    data_address: usize,
+    links: Links<dyn DeliverToRead>,
+}
+
+impl Transaction {
+    pub(crate) fn new(
+        node_ref: NodeRef,
+        stack_next: Option<Ref<Transaction>>,
+        from: &Ref<Thread>,
+        tr: &BinderTransactionData,
+    ) -> BinderResult<Ref<Self>> {
+        let allow_fds = node_ref.node.flags & FLAT_BINDER_FLAG_ACCEPTS_FDS != 0;
+        let to = node_ref.node.owner.clone();
+        let mut alloc = from.copy_transaction_data(&to, tr, allow_fds)?;
+        let data_address = alloc.ptr;
+        let file_list = alloc.take_file_list();
+        alloc.keep_alive();
+        let mut tr = Pin::from(UniqueRef::try_new(Self {
+            // SAFETY: `spinlock_init` is called below.
+            inner: unsafe { SpinLock::new(TransactionInner { file_list }) },
+            node_ref: Some(node_ref),
+            stack_next,
+            from: from.clone(),
+            to,
+            code: tr.code,
+            flags: tr.flags,
+            data_size: tr.data_size as _,
+            data_address,
+            offsets_size: tr.offsets_size as _,
+            links: Links::new(),
+            free_allocation: AtomicBool::new(true),
+        })?);
+
+        // SAFETY: `inner` is pinned when `tr` is.
+        let pinned = unsafe { tr.as_mut().map_unchecked_mut(|t| &mut t.inner) };
+        kernel::spinlock_init!(pinned, "Transaction::inner");
+
+        Ok(tr.into())
+    }
+
+    pub(crate) fn new_reply(
+        from: &Ref<Thread>,
+        to: Ref<Process>,
+        tr: &BinderTransactionData,
+        allow_fds: bool,
+    ) -> BinderResult<Ref<Self>> {
+        let mut alloc = from.copy_transaction_data(&to, tr, allow_fds)?;
+        let data_address = alloc.ptr;
+        let file_list = alloc.take_file_list();
+        alloc.keep_alive();
+        let mut tr = Pin::from(UniqueRef::try_new(Self {
+            // SAFETY: `spinlock_init` is called below.
+            inner: unsafe { SpinLock::new(TransactionInner { file_list }) },
+            node_ref: None,
+            stack_next: None,
+            from: from.clone(),
+            to,
+            code: tr.code,
+            flags: tr.flags,
+            data_size: tr.data_size as _,
+            data_address,
+            offsets_size: tr.offsets_size as _,
+            links: Links::new(),
+            free_allocation: AtomicBool::new(true),
+        })?);
+
+        // SAFETY: `inner` is pinned when `tr` is.
+        let pinned = unsafe { tr.as_mut().map_unchecked_mut(|t| &mut t.inner) };
+        kernel::spinlock_init!(pinned, "Transaction::inner");
+
+        Ok(tr.into())
+    }
+
+    /// Determines if the transaction is stacked on top of the given transaction.
+    pub(crate) fn is_stacked_on(&self, onext: &Option<Ref<Self>>) -> bool {
+        match (&self.stack_next, onext) {
+            (None, None) => true,
+            (Some(stack_next), Some(next)) => Ref::ptr_eq(stack_next, next),
+            _ => false,
+        }
+    }
+
+    /// Returns a pointer to the next transaction on the transaction stack, if there is one.
+    pub(crate) fn clone_next(&self) -> Option<Ref<Self>> {
+        let next = self.stack_next.as_ref()?;
+        Some(next.clone())
+    }
+
+    /// Searches in the transaction stack for a thread that belongs to the target process. This is
+    /// useful when finding a target for a new transaction: if the node belongs to a process that
+    /// is already part of the transaction stack, we reuse the thread.
+    fn find_target_thread(&self) -> Option<Ref<Thread>> {
+        let process = &self.node_ref.as_ref()?.node.owner;
+
+        let mut it = &self.stack_next;
+        while let Some(transaction) = it {
+            if Ref::ptr_eq(&transaction.from.process, process) {
+                return Some(transaction.from.clone());
+            }
+            it = &transaction.stack_next;
+        }
+        None
+    }
+
+    /// Searches in the transaction stack for a transaction originating at the given thread.
+    pub(crate) fn find_from(&self, thread: &Thread) -> Option<Ref<Transaction>> {
+        let mut it = &self.stack_next;
+        while let Some(transaction) = it {
+            if core::ptr::eq(thread, transaction.from.as_ref()) {
+                return Some(transaction.clone());
+            }
+
+            it = &transaction.stack_next;
+        }
+        None
+    }
+
+    /// Submits the transaction to a work queue. Use a thread if there is one in the transaction
+    /// stack, otherwise use the destination process.
+    pub(crate) fn submit(self: Ref<Self>) -> BinderResult {
+        if let Some(thread) = self.find_target_thread() {
+            thread.push_work(self)
+        } else {
+            let process = self.to.clone();
+            process.push_work(self)
+        }
+    }
+
+    /// Prepares the file list for delivery to the caller.
+    fn prepare_file_list(&self) -> Result<List<Box<FileInfo>>> {
+        // Get list of files that are being transferred as part of the transaction.
+        let mut file_list = core::mem::replace(&mut self.inner.lock().file_list, List::new());
+
+        // If the list is non-empty, prepare the buffer.
+        if !file_list.is_empty() {
+            let alloc = self.to.buffer_get(self.data_address).ok_or(ESRCH)?;
+            let cleanup = ScopeGuard::new(|| {
+                self.free_allocation.store(false, Ordering::Relaxed);
+            });
+
+            let mut it = file_list.cursor_front_mut();
+            while let Some(file_info) = it.current() {
+                let reservation = FileDescriptorReservation::new(bindings::O_CLOEXEC)?;
+                alloc.write(file_info.buffer_offset, &reservation.reserved_fd())?;
+                file_info.reservation = Some(reservation);
+                it.move_next();
+            }
+
+            alloc.keep_alive();
+            cleanup.dismiss();
+        }
+
+        Ok(file_list)
+    }
+}
+
+impl DeliverToRead for Transaction {
+    fn do_work(self: Ref<Self>, thread: &Thread, writer: &mut UserSlicePtrWriter) -> Result<bool> {
+        // TODO: Initialise the following fields from `tr`:
+        //   - `pub sender_pid: pid_t`.
+        //   - `pub sender_euid: uid_t`.
+
+        let send_failed_reply = ScopeGuard::new(|| {
+            if self.node_ref.is_some() && self.flags & TF_ONE_WAY == 0 {
+                let reply = Either::Right(BR_FAILED_REPLY);
+                self.from.deliver_reply(reply, &self);
+            }
+        });
+        let mut file_list = if let Ok(list) = self.prepare_file_list() {
+            list
+        } else {
+            // On failure to process the list, we send a reply back to the sender and ignore the
+            // transaction on the recipient.
+            return Ok(true);
+        };
+
+        let mut tr = BinderTransactionData::default();
+
+        if let Some(nref) = &self.node_ref {
+            let (ptr, cookie) = nref.node.get_id();
+            tr.target.ptr = ptr as _;
+            tr.cookie = cookie as _;
+        };
+
+        tr.code = self.code;
+        tr.flags = self.flags;
+        tr.data_size = self.data_size as _;
+        tr.data.ptr.buffer = self.data_address as _;
+        tr.offsets_size = self.offsets_size as _;
+        if tr.offsets_size > 0 {
+            tr.data.ptr.offsets = (self.data_address + ptr_align(self.data_size)) as _;
+        }
+
+        let code = if self.node_ref.is_none() {
+            BR_REPLY
+        } else {
+            BR_TRANSACTION
+        };
+
+        // Write the transaction code and data to the user buffer.
+        writer.write(&code)?;
+        writer.write(&tr)?;
+
+        // Dismiss the completion of transaction with a failure. No failure paths are allowed from
+        // here on out.
+        send_failed_reply.dismiss();
+
+        // Commit all files.
+        {
+            let mut it = file_list.cursor_front_mut();
+            while let Some(file_info) = it.current() {
+                if let Some(reservation) = file_info.reservation.take() {
+                    if let Some(file) = file_info.file.take() {
+                        reservation.commit(file);
+                    }
+                }
+
+                it.move_next();
+            }
+        }
+
+        // When `drop` is called, we don't want the allocation to be freed because it is now the
+        // user's reponsibility to free it.
+        //
+        // `drop` is guaranteed to see this relaxed store because `Ref` guarantess that everything
+        // that happens when an object is referenced happens-before the eventual `drop`.
+        self.free_allocation.store(false, Ordering::Relaxed);
+
+        // When this is not a reply and not an async transaction, update `current_transaction`. If
+        // it's a reply, `current_transaction` has already been updated appropriately.
+        if self.node_ref.is_some() && tr.flags & TF_ONE_WAY == 0 {
+            thread.set_current_transaction(self);
+        }
+
+        Ok(false)
+    }
+
+    fn cancel(self: Ref<Self>) {
+        let reply = Either::Right(BR_DEAD_REPLY);
+        self.from.deliver_reply(reply, &self);
+    }
+
+    fn get_links(&self) -> &Links<dyn DeliverToRead> {
+        &self.links
+    }
+}
+
+impl Drop for Transaction {
+    fn drop(&mut self) {
+        if self.free_allocation.load(Ordering::Relaxed) {
+            self.to.buffer_get(self.data_address);
+        }
+    }
+}
+
+pub(crate) struct FileInfo {
+    links: Links<FileInfo>,
+
+    /// The file for which a descriptor will be created in the recipient process.
+    file: Option<ARef<File>>,
+
+    /// The file descriptor reservation on the recipient process.
+    reservation: Option<FileDescriptorReservation>,
+
+    /// The offset in the buffer where the file descriptor is stored.
+    buffer_offset: usize,
+}
+
+impl FileInfo {
+    pub(crate) fn new(file: ARef<File>, buffer_offset: usize) -> Self {
+        Self {
+            file: Some(file),
+            reservation: None,
+            buffer_offset,
+            links: Links::new(),
+        }
+    }
+}
+
+impl GetLinks for FileInfo {
+    type EntryType = Self;
+
+    fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+        &data.links
+    }
+}
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 0642f579196f..0499c2facbb0 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -482,6 +482,14 @@ config GPIO_PL061
 	help
 	  Say yes here to support the PrimeCell PL061 GPIO device.
 
+config GPIO_PL061_RUST
+	tristate "PrimeCell PL061 GPIO support written in Rust"
+	depends on ARM_AMBA && RUST
+	select IRQ_DOMAIN
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support the PrimeCell PL061 GPIO device
+
 config GPIO_PMIC_EIC_SPRD
 	tristate "Spreadtrum PMIC EIC support"
 	depends on MFD_SC27XX_PMIC || COMPILE_TEST
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index a0985d30f51b..3fa4f3f93d85 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -119,6 +119,7 @@ obj-$(CONFIG_GPIO_PCIE_IDIO_24)		+= gpio-pcie-idio-24.o
 obj-$(CONFIG_GPIO_PCI_IDIO_16)		+= gpio-pci-idio-16.o
 obj-$(CONFIG_GPIO_PISOSR)		+= gpio-pisosr.o
 obj-$(CONFIG_GPIO_PL061)		+= gpio-pl061.o
+obj-$(CONFIG_GPIO_PL061_RUST)		+= gpio_pl061_rust.o
 obj-$(CONFIG_GPIO_PMIC_EIC_SPRD)	+= gpio-pmic-eic-sprd.o
 obj-$(CONFIG_GPIO_PXA)			+= gpio-pxa.o
 obj-$(CONFIG_GPIO_RASPBERRYPI_EXP)	+= gpio-raspberrypi-exp.o
diff --git a/drivers/gpio/gpio_pl061_rust.rs b/drivers/gpio/gpio_pl061_rust.rs
new file mode 100644
index 000000000000..d417fa3b0abc
--- /dev/null
+++ b/drivers/gpio/gpio_pl061_rust.rs
@@ -0,0 +1,367 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Driver for the ARM PrimeCell(tm) General Purpose Input/Output (PL061).
+//!
+//! Based on the C driver written by Baruch Siach <baruch@tkos.co.il>.
+
+use kernel::{
+    amba, bit, bits_iter, define_amba_id_table, device, gpio,
+    io_mem::IoMem,
+    irq::{self, ExtraResult, IrqData, LockedIrqData},
+    power,
+    prelude::*,
+    sync::{RawSpinLock, Ref, RefBorrow},
+};
+
+const GPIODIR: usize = 0x400;
+const GPIOIS: usize = 0x404;
+const GPIOIBE: usize = 0x408;
+const GPIOIEV: usize = 0x40C;
+const GPIOIE: usize = 0x410;
+const GPIOMIS: usize = 0x418;
+const GPIOIC: usize = 0x41C;
+const GPIO_SIZE: usize = 0x1000;
+
+const PL061_GPIO_NR: u16 = 8;
+
+#[derive(Default)]
+struct ContextSaveRegs {
+    gpio_data: u8,
+    gpio_dir: u8,
+    gpio_is: u8,
+    gpio_ibe: u8,
+    gpio_iev: u8,
+    gpio_ie: u8,
+}
+
+#[derive(Default)]
+struct PL061DataInner {
+    csave_regs: ContextSaveRegs,
+}
+
+struct PL061Data {
+    dev: device::Device,
+    inner: RawSpinLock<PL061DataInner>,
+}
+
+struct PL061Resources {
+    base: IoMem<GPIO_SIZE>,
+    parent_irq: u32,
+}
+
+type PL061Registrations = gpio::RegistrationWithIrqChip<PL061Device>;
+
+type DeviceData = device::Data<PL061Registrations, PL061Resources, PL061Data>;
+
+struct PL061Device;
+
+#[vtable]
+impl gpio::Chip for PL061Device {
+    type Data = Ref<DeviceData>;
+
+    fn get_direction(data: RefBorrow<'_, DeviceData>, offset: u32) -> Result<gpio::LineDirection> {
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        Ok(if pl061.base.readb(GPIODIR) & bit(offset) != 0 {
+            gpio::LineDirection::Out
+        } else {
+            gpio::LineDirection::In
+        })
+    }
+
+    fn direction_input(data: RefBorrow<'_, DeviceData>, offset: u32) -> Result {
+        let _guard = data.inner.lock_irqdisable();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        let mut gpiodir = pl061.base.readb(GPIODIR);
+        gpiodir &= !bit(offset);
+        pl061.base.writeb(gpiodir, GPIODIR);
+        Ok(())
+    }
+
+    fn direction_output(data: RefBorrow<'_, DeviceData>, offset: u32, value: bool) -> Result {
+        let woffset = bit(offset + 2).into();
+        let _guard = data.inner.lock_irqdisable();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        pl061.base.try_writeb((value as u8) << offset, woffset)?;
+        let mut gpiodir = pl061.base.readb(GPIODIR);
+        gpiodir |= bit(offset);
+        pl061.base.writeb(gpiodir, GPIODIR);
+
+        // gpio value is set again, because pl061 doesn't allow to set value of a gpio pin before
+        // configuring it in OUT mode.
+        pl061.base.try_writeb((value as u8) << offset, woffset)?;
+        Ok(())
+    }
+
+    fn get(data: RefBorrow<'_, DeviceData>, offset: u32) -> Result<bool> {
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        Ok(pl061.base.try_readb(bit(offset + 2).into())? != 0)
+    }
+
+    fn set(data: RefBorrow<'_, DeviceData>, offset: u32, value: bool) {
+        if let Some(pl061) = data.resources() {
+            let woffset = bit(offset + 2).into();
+            let _ = pl061.base.try_writeb((value as u8) << offset, woffset);
+        }
+    }
+}
+
+impl gpio::ChipWithIrqChip for PL061Device {
+    fn handle_irq_flow(
+        data: RefBorrow<'_, DeviceData>,
+        desc: &irq::Descriptor,
+        domain: &irq::Domain,
+    ) {
+        let chained = desc.enter_chained();
+
+        if let Some(pl061) = data.resources() {
+            let pending = pl061.base.readb(GPIOMIS);
+            for offset in bits_iter(pending) {
+                domain.generic_handle_chained(offset, &chained);
+            }
+        }
+    }
+}
+
+#[vtable]
+impl irq::Chip for PL061Device {
+    type Data = Ref<DeviceData>;
+
+    fn set_type(
+        data: RefBorrow<'_, DeviceData>,
+        irq_data: &mut LockedIrqData,
+        trigger: u32,
+    ) -> Result<ExtraResult> {
+        let offset = irq_data.hwirq();
+        let bit = bit(offset);
+
+        if offset >= PL061_GPIO_NR.into() {
+            return Err(EINVAL);
+        }
+
+        if trigger & (irq::Type::LEVEL_HIGH | irq::Type::LEVEL_LOW) != 0
+            && trigger & (irq::Type::EDGE_RISING | irq::Type::EDGE_FALLING) != 0
+        {
+            dev_err!(
+                data.dev,
+                "trying to configure line {} for both level and edge detection, choose one!\n",
+                offset
+            );
+            return Err(EINVAL);
+        }
+
+        let _guard = data.inner.lock_irqdisable();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+
+        let mut gpioiev = pl061.base.readb(GPIOIEV);
+        let mut gpiois = pl061.base.readb(GPIOIS);
+        let mut gpioibe = pl061.base.readb(GPIOIBE);
+
+        if trigger & (irq::Type::LEVEL_HIGH | irq::Type::LEVEL_LOW) != 0 {
+            let polarity = trigger & irq::Type::LEVEL_HIGH != 0;
+
+            // Disable edge detection.
+            gpioibe &= !bit;
+            // Enable level detection.
+            gpiois |= bit;
+            // Select polarity.
+            if polarity {
+                gpioiev |= bit;
+            } else {
+                gpioiev &= !bit;
+            }
+            irq_data.set_level_handler();
+            dev_dbg!(
+                data.dev,
+                "line {}: IRQ on {} level\n",
+                offset,
+                if polarity { "HIGH" } else { "LOW" }
+            );
+        } else if (trigger & irq::Type::EDGE_BOTH) == irq::Type::EDGE_BOTH {
+            // Disable level detection.
+            gpiois &= !bit;
+            // Select both edges, settings this makes GPIOEV be ignored.
+            gpioibe |= bit;
+            irq_data.set_edge_handler();
+            dev_dbg!(data.dev, "line {}: IRQ on both edges\n", offset);
+        } else if trigger & (irq::Type::EDGE_RISING | irq::Type::EDGE_FALLING) != 0 {
+            let rising = trigger & irq::Type::EDGE_RISING != 0;
+
+            // Disable level detection.
+            gpiois &= !bit;
+            // Clear detection on both edges.
+            gpioibe &= !bit;
+            // Select edge.
+            if rising {
+                gpioiev |= bit;
+            } else {
+                gpioiev &= !bit;
+            }
+            irq_data.set_edge_handler();
+            dev_dbg!(
+                data.dev,
+                "line {}: IRQ on {} edge\n",
+                offset,
+                if rising { "RISING" } else { "FALLING}" }
+            );
+        } else {
+            // No trigger: disable everything.
+            gpiois &= !bit;
+            gpioibe &= !bit;
+            gpioiev &= !bit;
+            irq_data.set_bad_handler();
+            dev_warn!(data.dev, "no trigger selected for line {}\n", offset);
+        }
+
+        pl061.base.writeb(gpiois, GPIOIS);
+        pl061.base.writeb(gpioibe, GPIOIBE);
+        pl061.base.writeb(gpioiev, GPIOIEV);
+
+        Ok(ExtraResult::None)
+    }
+
+    fn mask(data: RefBorrow<'_, DeviceData>, irq_data: &IrqData) {
+        let mask = bit(irq_data.hwirq() % irq::HwNumber::from(PL061_GPIO_NR));
+        let _guard = data.inner.lock();
+        if let Some(pl061) = data.resources() {
+            let gpioie = pl061.base.readb(GPIOIE) & !mask;
+            pl061.base.writeb(gpioie, GPIOIE);
+        }
+    }
+
+    fn unmask(data: RefBorrow<'_, DeviceData>, irq_data: &IrqData) {
+        let mask = bit(irq_data.hwirq() % irq::HwNumber::from(PL061_GPIO_NR));
+        let _guard = data.inner.lock();
+        if let Some(pl061) = data.resources() {
+            let gpioie = pl061.base.readb(GPIOIE) | mask;
+            pl061.base.writeb(gpioie, GPIOIE);
+        }
+    }
+
+    // This gets called from the edge IRQ handler to ACK the edge IRQ in the GPIOIC
+    // (interrupt-clear) register. For level IRQs this is not needed: these go away when the level
+    // signal goes away.
+    fn ack(data: RefBorrow<'_, DeviceData>, irq_data: &IrqData) {
+        let mask = bit(irq_data.hwirq() % irq::HwNumber::from(PL061_GPIO_NR));
+        let _guard = data.inner.lock();
+        if let Some(pl061) = data.resources() {
+            pl061.base.writeb(mask.into(), GPIOIC);
+        }
+    }
+
+    fn set_wake(data: RefBorrow<'_, DeviceData>, _irq_data: &IrqData, on: bool) -> Result {
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        irq::set_wake(pl061.parent_irq, on)
+    }
+}
+
+impl amba::Driver for PL061Device {
+    type Data = Ref<DeviceData>;
+    type PowerOps = Self;
+
+    define_amba_id_table! {(), [
+        ({id: 0x00041061, mask: 0x000fffff}, None),
+    ]}
+
+    fn probe(dev: &mut amba::Device, _data: Option<&Self::IdInfo>) -> Result<Ref<DeviceData>> {
+        let res = dev.take_resource().ok_or(ENXIO)?;
+        let irq = dev.irq(0).ok_or(ENXIO)?;
+
+        let mut data = kernel::new_device_data!(
+            gpio::RegistrationWithIrqChip::new(),
+            PL061Resources {
+                // SAFETY: This device doesn't support DMA.
+                base: unsafe { IoMem::try_new(res)? },
+                parent_irq: irq,
+            },
+            PL061Data {
+                dev: device::Device::from_dev(dev),
+                // SAFETY: We call `rawspinlock_init` below.
+                inner: unsafe { RawSpinLock::new(PL061DataInner::default()) },
+            },
+            "PL061::Registrations"
+        )?;
+
+        // SAFETY: General part of the data is pinned when `data` is.
+        let gen_inner = unsafe { data.as_mut().map_unchecked_mut(|d| &mut (**d).inner) };
+        kernel::rawspinlock_init!(gen_inner, "PL061Data::inner");
+
+        let data = Ref::<DeviceData>::from(data);
+
+        data.resources().ok_or(ENXIO)?.base.writeb(0, GPIOIE); // disable irqs
+
+        kernel::gpio_irq_chip_register!(
+            data.registrations().ok_or(ENXIO)?.as_pinned_mut(),
+            Self,
+            PL061_GPIO_NR,
+            None,
+            dev,
+            data.clone(),
+            irq
+        )?;
+
+        dev_info!(data.dev, "PL061 GPIO chip registered\n");
+
+        Ok(data)
+    }
+}
+
+impl power::Operations for PL061Device {
+    type Data = Ref<DeviceData>;
+
+    fn suspend(data: RefBorrow<'_, DeviceData>) -> Result {
+        let mut inner = data.inner.lock();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+        inner.csave_regs.gpio_data = 0;
+        inner.csave_regs.gpio_dir = pl061.base.readb(GPIODIR);
+        inner.csave_regs.gpio_is = pl061.base.readb(GPIOIS);
+        inner.csave_regs.gpio_ibe = pl061.base.readb(GPIOIBE);
+        inner.csave_regs.gpio_iev = pl061.base.readb(GPIOIEV);
+        inner.csave_regs.gpio_ie = pl061.base.readb(GPIOIE);
+
+        for offset in 0..PL061_GPIO_NR {
+            if inner.csave_regs.gpio_dir & bit(offset) != 0 {
+                if let Ok(v) = <Self as gpio::Chip>::get(data, offset.into()) {
+                    inner.csave_regs.gpio_data |= (v as u8) << offset;
+                }
+            }
+        }
+
+        Ok(())
+    }
+
+    fn resume(data: RefBorrow<'_, DeviceData>) -> Result {
+        let inner = data.inner.lock();
+        let pl061 = data.resources().ok_or(ENXIO)?;
+
+        for offset in 0..PL061_GPIO_NR {
+            if inner.csave_regs.gpio_dir & bit(offset) != 0 {
+                let value = inner.csave_regs.gpio_data & bit(offset) != 0;
+                let _ = <Self as gpio::Chip>::direction_output(data, offset.into(), value);
+            } else {
+                let _ = <Self as gpio::Chip>::direction_input(data, offset.into());
+            }
+        }
+
+        pl061.base.writeb(inner.csave_regs.gpio_is, GPIOIS);
+        pl061.base.writeb(inner.csave_regs.gpio_ibe, GPIOIBE);
+        pl061.base.writeb(inner.csave_regs.gpio_iev, GPIOIEV);
+        pl061.base.writeb(inner.csave_regs.gpio_ie, GPIOIE);
+
+        Ok(())
+    }
+
+    fn freeze(data: RefBorrow<'_, DeviceData>) -> Result {
+        Self::suspend(data)
+    }
+
+    fn restore(data: RefBorrow<'_, DeviceData>) -> Result {
+        Self::resume(data)
+    }
+}
+
+module_amba_driver! {
+    type: PL061Device,
+    name: b"pl061_gpio",
+    author: b"Wedson Almeida Filho",
+    license: b"GPL",
+}
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 4f2a819fd60a..50b3f6b9502e 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -4,8 +4,12 @@
 
 #ifndef __ASSEMBLY__
 
+/*
+ * Skipped when running bindgen due to a libclang issue;
+ * see https://github.com/rust-lang/rust-bindgen/issues/2244.
+ */
 #if defined(CONFIG_DEBUG_INFO_BTF) && defined(CONFIG_PAHOLE_HAS_BTF_TAG) && \
-	__has_attribute(btf_type_tag)
+	__has_attribute(btf_type_tag) && !defined(__BINDGEN__)
 # define BTF_TYPE_TAG(value) __attribute__((btf_type_tag(#value)))
 #else
 # define BTF_TYPE_TAG(value) /* nothing */
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index ad39636e0c3f..649faac31ddb 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -15,7 +15,7 @@
 
 #include <asm/sections.h>
 
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 512
 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s %s]") + \
 			(KSYM_NAME_LEN - 1) + \
 			2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + \
diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
index 5c0c5174155d..27df5380c1e4 100644
--- a/include/linux/spinlock.h
+++ b/include/linux/spinlock.h
@@ -99,11 +99,17 @@
   extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
 				   struct lock_class_key *key, short inner);
 
+static inline void _raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
+				       struct lock_class_key *key)
+{
+	__raw_spin_lock_init(lock, name, key, LD_WAIT_SPIN);
+}
+
 # define raw_spin_lock_init(lock)					\
 do {									\
 	static struct lock_class_key __key;				\
 									\
-	__raw_spin_lock_init((lock), #lock, &__key, LD_WAIT_SPIN);	\
+	_raw_spin_lock_init((lock), #lock, &__key);			\
 } while (0)
 
 #else
@@ -326,12 +332,17 @@ static __always_inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 
 #ifdef CONFIG_DEBUG_SPINLOCK
 
+static inline void __spin_lock_init(spinlock_t *lock, const char *name,
+				    struct lock_class_key *key)
+{
+	__raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG);
+}
+
 # define spin_lock_init(lock)					\
 do {								\
 	static struct lock_class_key __key;			\
 								\
-	__raw_spin_lock_init(spinlock_check(lock),		\
-			     #lock, &__key, LD_WAIT_CONFIG);	\
+	__spin_lock_init(lock, #lock, &__key);			\
 } while (0)
 
 #else
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index a0143dd24430..b6cc20b56560 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -221,24 +221,31 @@ static inline unsigned int work_static(struct work_struct *work) { return 0; }
  * to generate better code.
  */
 #ifdef CONFIG_LOCKDEP
-#define __INIT_WORK(_work, _func, _onstack)				\
+#define __INIT_WORK_WITH_KEY(_work, _func, _onstack, _key)		\
 	do {								\
-		static struct lock_class_key __key;			\
-									\
 		__init_work((_work), _onstack);				\
 		(_work)->data = (atomic_long_t) WORK_DATA_INIT();	\
-		lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, &__key, 0); \
+		lockdep_init_map(&(_work)->lockdep_map, "(work_completion)"#_work, _key, 0); \
 		INIT_LIST_HEAD(&(_work)->entry);			\
 		(_work)->func = (_func);				\
 	} while (0)
-#else
+
 #define __INIT_WORK(_work, _func, _onstack)				\
 	do {								\
+		static struct lock_class_key __key;			\
+		__INIT_WORK_WITH_KEY(_work, _func, _onstack, &__key);	\
+	} while (0)
+#else
+#define __INIT_WORK_WITH_KEY(_work, _func, _onstack, _key)		\
+	do {								\
 		__init_work((_work), _onstack);				\
 		(_work)->data = (atomic_long_t) WORK_DATA_INIT();	\
 		INIT_LIST_HEAD(&(_work)->entry);			\
 		(_work)->func = (_func);				\
 	} while (0)
+
+#define __INIT_WORK(_work, _func, _onstack)				\
+	__INIT_WORK_WITH_KEY(_work, _func, _onstack, NULL)
 #endif
 
 #define INIT_WORK(_work, _func)						\
diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h
index e72e4de8f452..0b8ff0850093 100644
--- a/include/uapi/linux/android/binder.h
+++ b/include/uapi/linux/android/binder.h
@@ -251,20 +251,22 @@ struct binder_extended_error {
 	__s32	param;
 };
 
-#define BINDER_WRITE_READ		_IOWR('b', 1, struct binder_write_read)
-#define BINDER_SET_IDLE_TIMEOUT		_IOW('b', 3, __s64)
-#define BINDER_SET_MAX_THREADS		_IOW('b', 5, __u32)
-#define BINDER_SET_IDLE_PRIORITY	_IOW('b', 6, __s32)
-#define BINDER_SET_CONTEXT_MGR		_IOW('b', 7, __s32)
-#define BINDER_THREAD_EXIT		_IOW('b', 8, __s32)
-#define BINDER_VERSION			_IOWR('b', 9, struct binder_version)
-#define BINDER_GET_NODE_DEBUG_INFO	_IOWR('b', 11, struct binder_node_debug_info)
-#define BINDER_GET_NODE_INFO_FOR_REF	_IOWR('b', 12, struct binder_node_info_for_ref)
-#define BINDER_SET_CONTEXT_MGR_EXT	_IOW('b', 13, struct flat_binder_object)
-#define BINDER_FREEZE			_IOW('b', 14, struct binder_freeze_info)
-#define BINDER_GET_FROZEN_INFO		_IOWR('b', 15, struct binder_frozen_status_info)
-#define BINDER_ENABLE_ONEWAY_SPAM_DETECTION	_IOW('b', 16, __u32)
-#define BINDER_GET_EXTENDED_ERROR	_IOWR('b', 17, struct binder_extended_error)
+enum {
+	BINDER_WRITE_READ		= _IOWR('b', 1, struct binder_write_read),
+	BINDER_SET_IDLE_TIMEOUT		= _IOW('b', 3, __s64),
+	BINDER_SET_MAX_THREADS		= _IOW('b', 5, __u32),
+	BINDER_SET_IDLE_PRIORITY	= _IOW('b', 6, __s32),
+	BINDER_SET_CONTEXT_MGR		= _IOW('b', 7, __s32),
+	BINDER_THREAD_EXIT		= _IOW('b', 8, __s32),
+	BINDER_VERSION			= _IOWR('b', 9, struct binder_version),
+	BINDER_GET_NODE_DEBUG_INFO	= _IOWR('b', 11, struct binder_node_debug_info),
+	BINDER_GET_NODE_INFO_FOR_REF	= _IOWR('b', 12, struct binder_node_info_for_ref),
+	BINDER_SET_CONTEXT_MGR_EXT	= _IOW('b', 13, struct flat_binder_object),
+	BINDER_FREEZE			= _IOW('b', 14, struct binder_freeze_info),
+	BINDER_GET_FROZEN_INFO		= _IOWR('b', 15, struct binder_frozen_status_info),
+	BINDER_ENABLE_ONEWAY_SPAM_DETECTION	= _IOW('b', 16, __u32),
+	BINDER_GET_EXTENDED_ERROR	= _IOWR('b', 17, struct binder_extended_error),
+};
 
 /*
  * NOTE: Two special error codes you should check for when calling
diff --git a/init/Kconfig b/init/Kconfig
index 80fe60fa77fb..1dcfc714b1db 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -60,6 +60,23 @@ config LLD_VERSION
 	default $(ld-version) if LD_IS_LLD
 	default 0
 
+config RUST_IS_AVAILABLE
+	# Because some common tools like 'diff' don't support permissions of
+	# the files, 'rust-is-available.sh' in some trees that managed with such
+	# tools result in having no execution permission.  As a temporal work
+	# around, we specify the interpreter ('/bin/sh').  It will be unneeded
+	# once 'rust-is-available.sh' is merged in the mainline with its execution
+	# permission.
+	def_bool $(success,/bin/sh $(srctree)/scripts/rust-is-available.sh)
+	help
+	  This shows whether a suitable Rust toolchain is available (found).
+
+	  Please see Documentation/rust/quick-start.rst for instructions on how
+	  to satify the build requirements of Rust support.
+
+	  In particular, the Makefile target 'rustavailable' is useful to check
+	  why the Rust toolchain is not being detected.
+
 config CC_CAN_LINK
 	bool
 	default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT
@@ -151,7 +168,8 @@ config WERROR
 	default COMPILE_TEST
 	help
 	  A kernel build should not cause any compiler warnings, and this
-	  enables the '-Werror' flag to enforce that rule by default.
+	  enables the '-Werror' (for C) and '-Dwarnings' (for Rust) flags
+	  to enforce that rule by default.
 
 	  However, if you have a new (or very old) compiler with odd and
 	  unusual warnings, or you have some architecture with problems,
@@ -1903,6 +1921,38 @@ config PROFILING
 	  Say Y here to enable the extended profiling support mechanisms used
 	  by profilers.
 
+config RUST
+	bool "Rust support"
+	depends on HAVE_RUST
+	depends on RUST_IS_AVAILABLE
+	depends on !MODVERSIONS
+	depends on !GCC_PLUGINS
+	depends on !RANDSTRUCT
+	depends on !DEBUG_INFO_BTF
+	select CONSTRUCTORS
+	help
+	  Enables Rust support in the kernel.
+
+	  This allows other Rust-related options, like drivers written in Rust,
+	  to be selected.
+
+	  It is also required to be able to load external kernel modules
+	  written in Rust.
+
+	  See Documentation/rust/ for more information.
+
+	  If unsure, say N.
+
+config RUSTC_VERSION_TEXT
+	string
+	depends on RUST
+	default $(shell,command -v $(RUSTC) >/dev/null 2>&1 && $(RUSTC) --version || echo n)
+
+config BINDGEN_VERSION_TEXT
+	string
+	depends on RUST
+	default $(shell,command -v $(BINDGEN) >/dev/null 2>&1 && $(BINDGEN) --version || echo n)
+
 #
 # Place an empty function call at each tracepoint site. Can be
 # dynamically changed for a probe function.
diff --git a/kernel/configs/rust.config b/kernel/configs/rust.config
new file mode 100644
index 000000000000..38a7c5362c9c
--- /dev/null
+++ b/kernel/configs/rust.config
@@ -0,0 +1 @@
+CONFIG_RUST=y
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 79a85834ce9d..671de0351720 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -71,12 +71,20 @@ static unsigned int kallsyms_expand_symbol(unsigned int off,
 	data = &kallsyms_names[off];
 	len = *data;
 	data++;
+	off++;
+
+	/* If MSB is 1, it is a "big" symbol, so needs an additional byte. */
+	if ((len & 0x80) != 0) {
+		len = (len & 0x7F) | (*data << 7);
+		data++;
+		off++;
+	}
 
 	/*
 	 * Update the offset to return the offset for the next symbol on
 	 * the compressed stream.
 	 */
-	off += len + 1;
+	off += len;
 
 	/*
 	 * For every byte on the compressed symbol data, copy the table
@@ -129,7 +137,7 @@ static char kallsyms_get_symbol_type(unsigned int off)
 static unsigned int get_symbol_offset(unsigned long pos)
 {
 	const u8 *name;
-	int i;
+	int i, len;
 
 	/*
 	 * Use the closest marker we have. We have markers every 256 positions,
@@ -143,8 +151,18 @@ static unsigned int get_symbol_offset(unsigned long pos)
 	 * so we just need to add the len to the current pointer for every
 	 * symbol we wish to skip.
 	 */
-	for (i = 0; i < (pos & 0xFF); i++)
-		name = name + (*name) + 1;
+	for (i = 0; i < (pos & 0xFF); i++) {
+		len = *name;
+
+		/*
+		 * If MSB is 1, it is a "big" symbol, so we need to look into
+		 * the next byte (and skip it, too).
+		 */
+		if ((len & 0x80) != 0)
+			len = ((len & 0x7F) | (name[1] << 7)) + 1;
+
+		name = name + len + 1;
+	}
 
 	return name - kallsyms_names;
 }
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index bc475e62279d..ec06ce59d728 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -213,7 +213,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
 	 * we use the smallest/strictest upper bound possible (56, based on
 	 * the current definition of MODULE_NAME_LEN) to prevent overflows.
 	 */
-	BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128);
+	BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 512);
 
 	relas = (Elf_Rela *) relasec->sh_addr;
 	/* For each rela in this klp relocation section */
@@ -227,7 +227,7 @@ static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
 
 		/* Format: .klp.sym.sym_objname.sym_name,sympos */
 		cnt = sscanf(strtab + sym->st_name,
-			     ".klp.sym.%55[^.].%127[^,],%lu",
+			     ".klp.sym.%55[^.].%511[^,],%lu",
 			     sym_objname, sym_name, &sympos);
 		if (cnt != 3) {
 			pr_err("symbol %s has an incorrectly formatted name\n",
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 35cd8287642a..74d56efc7416 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2688,6 +2688,88 @@ config HYPERV_TESTING
 
 endmenu # "Kernel Testing and Coverage"
 
+menu "Rust hacking"
+
+config RUST_DEBUG_ASSERTIONS
+	bool "Debug assertions"
+	depends on RUST
+	help
+	  Enables rustc's `-Cdebug-assertions` codegen option.
+
+	  This flag lets you turn `cfg(debug_assertions)` conditional
+	  compilation on or off. This can be used to enable extra debugging
+	  code in development but not in production. For example, it controls
+	  the behavior of the standard library's `debug_assert!` macro.
+
+	  Note that this will apply to all Rust code, including `core`.
+
+	  If unsure, say N.
+
+config RUST_OVERFLOW_CHECKS
+	bool "Overflow checks"
+	default y
+	depends on RUST
+	help
+	  Enables rustc's `-Coverflow-checks` codegen option.
+
+	  This flag allows you to control the behavior of runtime integer
+	  overflow. When overflow-checks are enabled, a Rust panic will occur
+	  on overflow.
+
+	  Note that this will apply to all Rust code, including `core`.
+
+	  If unsure, say Y.
+
+choice
+	prompt "Build-time assertions"
+	default RUST_BUILD_ASSERT_DENY
+	depends on RUST
+	help
+	  Controls how are `build_error!` and `build_assert!` handled during build.
+
+	  If calls to them exist in the binary, it may indicate a violated invariant
+	  or that the optimizer failed to verify the invariant during compilation.
+	  You can choose to abort compilation or ignore them during build and let the
+	  check be carried to runtime.
+
+	  If optimizations are turned off, you cannot select "Deny".
+
+	  If unsure, say "Deny".
+
+config RUST_BUILD_ASSERT_ALLOW
+	bool "Allow"
+	help
+	  Unoptimized calls to `build_error!` will be converted to `panic!`
+	  and checked at runtime.
+
+config RUST_BUILD_ASSERT_WARN
+	bool "Warn"
+	help
+	  Unoptimized calls to `build_error!` will be converted to `panic!`
+	  and checked at runtime, but warnings will be generated when building.
+
+config RUST_BUILD_ASSERT_DENY
+	bool "Deny"
+	help
+	  Unoptimized calls to `build_error!` will abort compilation.
+
+endchoice
+
+config RUST_KERNEL_KUNIT_TEST
+	bool "KUnit test for the `kernel` crate" if !KUNIT_ALL_TESTS
+	depends on RUST && KUNIT=y
+	default KUNIT_ALL_TESTS
+	help
+	  This builds the documentation tests of the `kernel` crate
+	  as KUnit tests.
+
+	  For more information on KUnit and unit tests in general,
+	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+	  If unsure, say N.
+
+endmenu # "Rust"
+
 source "Documentation/Kconfig"
 
 endmenu # Kernel hacking
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 3c1853a9d1c0..c414a8d9f1ea 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2246,6 +2246,9 @@ int __init no_hash_pointers_enable(char *str)
 }
 early_param("no_hash_pointers", no_hash_pointers_enable);
 
+/* Used for Rust formatting ('%pA'). */
+char *rust_fmt_argument(char *buf, char *end, void *ptr);
+
 /*
  * Show a '%p' thing.  A kernel extension is that the '%p' is followed
  * by an extra set of alphanumeric characters that are extended format
@@ -2372,6 +2375,10 @@ early_param("no_hash_pointers", no_hash_pointers_enable);
  *
  * Note: The default behaviour (unadorned %p) is to hash the address,
  * rendering it useful as a unique identifier.
+ *
+ * There is also a '%pA' format specifier, but it is only intended to be used
+ * from Rust code to format core::fmt::Arguments. Do *not* use it from C.
+ * See rust/kernel/print.rs for details.
  */
 static noinline_for_stack
 char *pointer(const char *fmt, char *buf, char *end, void *ptr,
@@ -2444,6 +2451,12 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 		return device_node_string(buf, end, ptr, spec, fmt + 1);
 	case 'f':
 		return fwnode_string(buf, end, ptr, spec, fmt + 1);
+	case 'A':
+		if (!IS_ENABLED(CONFIG_RUST)) {
+			WARN_ONCE(1, "Please remove %%pA from non-Rust code\n");
+			return error_string(buf, end, "(%pA?)", spec);
+		}
+		return rust_fmt_argument(buf, end, ptr);
 	case 'x':
 		return pointer_string(buf, end, ptr, spec);
 	case 'e':
diff --git a/rust/.gitignore b/rust/.gitignore
new file mode 100644
index 000000000000..89b602d91109
--- /dev/null
+++ b/rust/.gitignore
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+
+target.json
+bindings_generated.rs
+bindings_helpers_generated.rs
+exports_*_generated.h
+doctests_kernel_generated.rs
+doctests_kernel_generated_kunit.c
+doc/
+test/
diff --git a/rust/Makefile b/rust/Makefile
new file mode 100644
index 000000000000..30ce13fa8dad
--- /dev/null
+++ b/rust/Makefile
@@ -0,0 +1,415 @@
+# SPDX-License-Identifier: GPL-2.0
+
+always-$(CONFIG_RUST) += target.json
+no-clean-files += target.json
+
+obj-$(CONFIG_RUST) += core.o compiler_builtins.o
+always-$(CONFIG_RUST) += exports_core_generated.h
+
+# Missing prototypes are expected in the helpers since these are exported
+# for Rust only, thus there is no header nor prototypes.
+obj-$(CONFIG_RUST) += helpers.o
+CFLAGS_REMOVE_helpers.o = -Wmissing-prototypes -Wmissing-declarations
+
+always-$(CONFIG_RUST) += libmacros.so
+no-clean-files += libmacros.so
+
+always-$(CONFIG_RUST) += bindings/bindings_generated.rs bindings/bindings_helpers_generated.rs
+obj-$(CONFIG_RUST) += alloc.o bindings.o kernel.o
+always-$(CONFIG_RUST) += exports_alloc_generated.h exports_bindings_generated.h \
+    exports_kernel_generated.h
+
+ifdef CONFIG_RUST_BUILD_ASSERT_DENY
+always-$(CONFIG_RUST) += build_error.o
+else
+obj-$(CONFIG_RUST) += build_error.o
+endif
+
+obj-$(CONFIG_RUST) += exports.o
+
+obj-$(CONFIG_RUST_KERNEL_KUNIT_TEST) += doctests_kernel_generated.o
+obj-$(CONFIG_RUST_KERNEL_KUNIT_TEST) += doctests_kernel_generated_kunit.o
+
+# Avoids running `$(RUSTC)` for the sysroot when it may not be available.
+ifdef CONFIG_RUST
+
+# `$(rust_flags)` is passed in case the user added `--sysroot`.
+rustc_sysroot := $(shell $(RUSTC) $(rust_flags) --print sysroot)
+rustc_host_target := $(shell $(RUSTC) --version --verbose | grep -F 'host: ' | cut -d' ' -f2)
+RUST_LIB_SRC ?= $(rustc_sysroot)/lib/rustlib/src/rust/library
+
+ifeq ($(quiet),silent_)
+cargo_quiet=-q
+rust_test_quiet=-q
+rustdoc_test_quiet=--test-args -q
+rustdoc_test_kernel_quiet=>/dev/null
+else ifeq ($(quiet),quiet_)
+rust_test_quiet=-q
+rustdoc_test_quiet=--test-args -q
+rustdoc_test_kernel_quiet=>/dev/null
+else
+cargo_quiet=--verbose
+endif
+
+core-cfgs = \
+    --cfg no_fp_fmt_parse
+
+alloc-cfgs = \
+    --cfg no_global_oom_handling \
+    --cfg no_rc \
+    --cfg no_sync
+
+quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $<
+      cmd_rustdoc = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTDOC) $(if $(rustdoc_host),$(rust_common_flags),$(rust_flags)) \
+		$(rustc_target_flags) -L$(objtree)/$(obj) \
+		--output $(objtree)/$(obj)/doc \
+		--crate-name $(subst rustdoc-,,$@) \
+		@$(objtree)/include/generated/rustc_cfg $<
+
+# The `html_logo_url` and `html_favicon_url` forms of the `doc` attribute
+# can be used to specify a custom logo. However:
+#   - The given value is used as-is, thus it cannot be relative or a local file
+#     (unlike the non-custom case) since the generated docs have subfolders.
+#   - It requires adding it to every crate.
+#   - It requires changing `core` which comes from the sysroot.
+#
+# Using `-Zcrate-attr` would solve the last two points, but not the first.
+# The https://github.com/rust-lang/rfcs/pull/3226 RFC suggests two new
+# command-like flags to solve the issue. Meanwhile, we use the non-custom case
+# and then retouch the generated files.
+rustdoc: rustdoc-core rustdoc-macros rustdoc-compiler_builtins \
+    rustdoc-alloc rustdoc-kernel
+	$(Q)cp $(srctree)/Documentation/images/logo.svg $(objtree)/$(obj)/doc
+	$(Q)cp $(srctree)/Documentation/images/COPYING-logo $(objtree)/$(obj)/doc
+	$(Q)find $(objtree)/$(obj)/doc -name '*.html' -type f -print0 | xargs -0 sed -Ei \
+		-e 's:rust-logo\.svg:logo.svg:g' \
+		-e 's:rust-logo\.png:logo.svg:g' \
+		-e 's:favicon\.svg:logo.svg:g' \
+		-e 's:<link rel="alternate icon" type="image/png" href="[./]*favicon-(16x16|32x32)\.png">::g'
+	$(Q)echo '.logo-container > img { object-fit: contain; }' \
+		>> $(objtree)/$(obj)/doc/rustdoc.css
+
+rustdoc-macros: private rustdoc_host = yes
+rustdoc-macros: private rustc_target_flags = --crate-type proc-macro \
+    --extern proc_macro
+rustdoc-macros: $(src)/macros/lib.rs FORCE
+	$(call if_changed,rustdoc)
+
+rustdoc-core: private rustc_target_flags = $(core-cfgs)
+rustdoc-core: $(RUST_LIB_SRC)/core/src/lib.rs FORCE
+	$(call if_changed,rustdoc)
+
+rustdoc-compiler_builtins: $(src)/compiler_builtins.rs rustdoc-core FORCE
+	$(call if_changed,rustdoc)
+
+# We need to allow `rustdoc::broken_intra_doc_links` because some
+# `no_global_oom_handling` functions refer to non-`no_global_oom_handling`
+# functions. Ideally `rustdoc` would have a way to distinguish broken links
+# due to things that are "configured out" vs. entirely non-existing ones.
+rustdoc-alloc: private rustc_target_flags = $(alloc-cfgs) \
+    -Arustdoc::broken_intra_doc_links
+rustdoc-alloc: $(src)/alloc/lib.rs rustdoc-core rustdoc-compiler_builtins FORCE
+	$(call if_changed,rustdoc)
+
+rustdoc-kernel: private rustc_target_flags = --extern alloc \
+    --extern build_error --extern macros=$(objtree)/$(obj)/libmacros.so \
+    --extern bindings
+rustdoc-kernel: $(src)/kernel/lib.rs rustdoc-core rustdoc-macros \
+    rustdoc-compiler_builtins rustdoc-alloc $(obj)/libmacros.so \
+    $(obj)/bindings.o FORCE
+	$(call if_changed,rustdoc)
+
+quiet_cmd_rustc_test_library = RUSTC TL $<
+      cmd_rustc_test_library = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTC) $(rust_common_flags) \
+		@$(objtree)/include/generated/rustc_cfg $(rustc_target_flags) \
+		--crate-type $(if $(rustc_test_library_proc),proc-macro,rlib) \
+		--out-dir $(objtree)/$(obj)/test --cfg testlib \
+		--sysroot $(objtree)/$(obj)/test/sysroot \
+		-L$(objtree)/$(obj)/test \
+		--crate-name $(subst rusttest-,,$(subst rusttestlib-,,$@)) $<
+
+rusttestlib-build_error: $(src)/build_error.rs rusttest-prepare FORCE
+	$(call if_changed,rustc_test_library)
+
+rusttestlib-macros: private rustc_target_flags = --extern proc_macro
+rusttestlib-macros: private rustc_test_library_proc = yes
+rusttestlib-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
+	$(call if_changed,rustc_test_library)
+
+rusttestlib-bindings: $(src)/bindings/lib.rs rusttest-prepare FORCE
+	$(call if_changed,rustc_test_library)
+
+quiet_cmd_rustdoc_test = RUSTDOC T $<
+      cmd_rustdoc_test = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTDOC) --test $(rust_common_flags) \
+		@$(objtree)/include/generated/rustc_cfg \
+		$(rustc_target_flags) $(rustdoc_test_target_flags) \
+		--sysroot $(objtree)/$(obj)/test/sysroot $(rustdoc_test_quiet) \
+		-L$(objtree)/$(obj)/test --output $(objtree)/$(obj)/doc \
+		--crate-name $(subst rusttest-,,$@) $<
+
+quiet_cmd_rustdoc_test_kernel = RUSTDOC TK $<
+      cmd_rustdoc_test_kernel = \
+	rm -rf $(objtree)/$(obj)/test/doctests/kernel; \
+	mkdir -p $(objtree)/$(obj)/test/doctests/kernel; \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTDOC) --test $(rust_flags) \
+		@$(objtree)/include/generated/rustc_cfg \
+		-L$(objtree)/$(obj) --extern alloc --extern kernel \
+		--extern build_error --extern macros \
+		--extern bindings \
+		--no-run --crate-name kernel -Zunstable-options \
+		--test-builder $(srctree)/scripts/rustdoc_test_builder.py \
+		$< $(rustdoc_test_kernel_quiet); \
+	$(srctree)/scripts/rustdoc_test_gen.py
+
+%/doctests_kernel_generated.rs %/doctests_kernel_generated_kunit.c: $(src)/kernel/lib.rs $(obj)/kernel.o FORCE
+	$(call if_changed,rustdoc_test_kernel)
+
+# We cannot use `-Zpanic-abort-tests` because some tests are dynamic,
+# so for the moment we skip `-Cpanic=abort`.
+quiet_cmd_rustc_test = RUSTC T  $<
+      cmd_rustc_test = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(RUSTC) --test $(rust_common_flags) \
+		@$(objtree)/include/generated/rustc_cfg \
+		$(rustc_target_flags) --out-dir $(objtree)/$(obj)/test \
+		--sysroot $(objtree)/$(obj)/test/sysroot \
+		-L$(objtree)/$(obj)/test \
+		--crate-name $(subst rusttest-,,$@) $<; \
+	$(objtree)/$(obj)/test/$(subst rusttest-,,$@) $(rust_test_quiet) \
+		$(rustc_test_run_flags)
+
+rusttest: rusttest-macros rusttest-kernel
+
+# This prepares a custom sysroot with our custom `alloc` instead of
+# the standard one.
+#
+# This requires several hacks:
+#   - Unlike `core` and `alloc`, `std` depends on more than a dozen crates,
+#     including third-party crates that need to be downloaded, plus custom
+#     `build.rs` steps. Thus hardcoding things here is not maintainable.
+#   - `cargo` knows how to build the standard library, but it is an unstable
+#     feature so far (`-Zbuild-std`).
+#   - `cargo` only considers the use case of building the standard library
+#     to use it in a given package. Thus we need to create a dummy package
+#     and pick the generated libraries from there.
+#   - Since we only keep a subset of upstream `alloc` in-tree, we need
+#     to recreate it on the fly by putting our sources on top.
+#   - The usual ways of modifying the dependency graph in `cargo` do not seem
+#     to apply for the `-Zbuild-std` steps, thus we have to mislead it
+#     by modifying the sources in the sysroot.
+#   - To avoid messing with the user's Rust installation, we create a clone
+#     of the sysroot. However, `cargo` ignores `RUSTFLAGS` in the `-Zbuild-std`
+#     steps, thus we use a wrapper binary passed via `RUSTC` to pass the flag.
+#
+# In the future, we hope to avoid the whole ordeal by either:
+#   - Making the `test` crate not depend on `std` (either improving upstream
+#     or having our own custom crate).
+#   - Making the tests run in kernel space (requires the previous point).
+#   - Making `std` and friends be more like a "normal" crate, so that
+#     `-Zbuild-std` and related hacks are not needed.
+quiet_cmd_rustsysroot = RUSTSYSROOT
+      cmd_rustsysroot = \
+	rm -rf $(objtree)/$(obj)/test; \
+	mkdir -p $(objtree)/$(obj)/test; \
+	cp -a $(rustc_sysroot) $(objtree)/$(obj)/test/sysroot; \
+	cp -r $(srctree)/$(src)/alloc/* \
+		$(objtree)/$(obj)/test/sysroot/lib/rustlib/src/rust/library/alloc/src; \
+	echo '\#!/bin/sh' > $(objtree)/$(obj)/test/rustc_sysroot; \
+	echo "$(RUSTC) --sysroot=$(abspath $(objtree)/$(obj)/test/sysroot) \"\$$@\"" \
+		>> $(objtree)/$(obj)/test/rustc_sysroot; \
+	chmod u+x $(objtree)/$(obj)/test/rustc_sysroot; \
+	$(CARGO) -q new $(objtree)/$(obj)/test/dummy; \
+	RUSTC=$(objtree)/$(obj)/test/rustc_sysroot $(CARGO) $(cargo_quiet) \
+		test -Zbuild-std --target $(rustc_host_target) \
+		--manifest-path $(objtree)/$(obj)/test/dummy/Cargo.toml; \
+	rm $(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib/*; \
+	cp $(objtree)/$(obj)/test/dummy/target/$(rustc_host_target)/debug/deps/* \
+		$(objtree)/$(obj)/test/sysroot/lib/rustlib/$(rustc_host_target)/lib
+
+rusttest-prepare: FORCE
+	$(call if_changed,rustsysroot)
+
+rusttest-macros: private rustc_target_flags = --extern proc_macro
+rusttest-macros: private rustdoc_test_target_flags = --crate-type proc-macro
+rusttest-macros: $(src)/macros/lib.rs rusttest-prepare FORCE
+	$(call if_changed,rustc_test)
+	$(call if_changed,rustdoc_test)
+
+rusttest-kernel: private rustc_target_flags = --extern alloc \
+    --extern build_error --extern macros --extern bindings
+rusttest-kernel: $(src)/kernel/lib.rs rusttest-prepare \
+    rusttestlib-build_error rusttestlib-macros rusttestlib-bindings FORCE
+	$(call if_changed,rustc_test)
+	$(call if_changed,rustc_test_library)
+
+filechk_rust_target = $(objtree)/scripts/generate_rust_target < $<
+
+$(obj)/target.json: $(objtree)/include/config/auto.conf FORCE
+	$(call filechk,rust_target)
+
+ifdef CONFIG_CC_IS_CLANG
+bindgen_c_flags = $(c_flags)
+else
+# bindgen relies on libclang to parse C. Ideally, bindgen would support a GCC
+# plugin backend and/or the Clang driver would be perfectly compatible with GCC.
+#
+# For the moment, here we are tweaking the flags on the fly. This is a hack,
+# and some kernel configurations may not work (e.g. `GCC_PLUGIN_RANDSTRUCT`
+# if we end up using one of those structs).
+bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \
+	-mskip-rax-setup -mgeneral-regs-only -msign-return-address=% \
+	-mindirect-branch=thunk-extern -mindirect-branch-register \
+	-mfunction-return=thunk-extern -mrecord-mcount -mabi=lp64 \
+	-mstack-protector-guard% -mtraceback=no \
+	-mno-pointers-to-nested-functions -mno-string \
+	-mno-strict-align -mstrict-align \
+	-fconserve-stack -falign-jumps=% -falign-loops=% \
+	-femit-struct-debug-baseonly -fno-ipa-cp-clone -fno-ipa-sra \
+	-fno-partial-inlining -fplugin-arg-arm_ssp_per_task_plugin-% \
+	-fno-reorder-blocks -fno-allow-store-data-races -fasan-shadow-offset=% \
+	-fzero-call-used-regs=% -fno-stack-clash-protection \
+	-fno-inline-functions-called-once \
+	--param=% --param asan-%
+
+# Derived from `scripts/Makefile.clang`.
+BINDGEN_TARGET_arm	:= arm-linux-gnueabi
+BINDGEN_TARGET_arm64	:= aarch64-linux-gnu
+BINDGEN_TARGET_powerpc	:= powerpc64le-linux-gnu
+BINDGEN_TARGET_riscv	:= riscv64-linux-gnu
+BINDGEN_TARGET_x86	:= x86_64-linux-gnu
+BINDGEN_TARGET		:= $(BINDGEN_TARGET_$(SRCARCH))
+
+# All warnings are inhibited since GCC builds are very experimental,
+# many GCC warnings are not supported by Clang, they may only appear in
+# some configurations, with new GCC versions, etc.
+bindgen_extra_c_flags = -w --target=$(BINDGEN_TARGET)
+
+bindgen_c_flags = $(filter-out $(bindgen_skip_c_flags), $(c_flags)) \
+	$(bindgen_extra_c_flags)
+endif
+
+ifdef CONFIG_LTO
+bindgen_c_flags_lto = $(filter-out $(CC_FLAGS_LTO), $(bindgen_c_flags))
+else
+bindgen_c_flags_lto = $(bindgen_c_flags)
+endif
+
+bindgen_c_flags_final = $(bindgen_c_flags_lto) -D__BINDGEN__
+
+quiet_cmd_bindgen = BINDGEN $@
+      cmd_bindgen = \
+	$(BINDGEN) $< $(bindgen_target_flags) \
+		--use-core --with-derive-default --ctypes-prefix core::ffi --no-layout-tests \
+		--no-debug '.*' \
+		--size_t-is-usize -o $@ -- $(bindgen_c_flags_final) -DMODULE \
+		$(bindgen_target_cflags) $(bindgen_target_extra)
+
+$(obj)/bindings/bindings_generated.rs: private bindgen_target_flags = \
+    $(shell grep -v '^\#\|^$$' $(srctree)/$(src)/bindgen_parameters)
+$(obj)/bindings/bindings_generated.rs: $(src)/bindings/bindings_helper.h \
+    $(src)/bindgen_parameters FORCE
+	$(call if_changed_dep,bindgen)
+
+# See `CFLAGS_REMOVE_helpers.o` above. In addition, Clang on C does not warn
+# with `-Wmissing-declarations` (unlike GCC), so it is not strictly needed here
+# given it is `libclang`; but for consistency, future Clang changes and/or
+# a potential future GCC backend for `bindgen`, we disable it too.
+$(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_flags = \
+    --blacklist-type '.*' --whitelist-var '' \
+    --whitelist-function 'rust_helper_.*'
+$(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_cflags = \
+    -I$(objtree)/$(obj) -Wno-missing-prototypes -Wno-missing-declarations
+$(obj)/bindings/bindings_helpers_generated.rs: private bindgen_target_extra = ; \
+    sed -Ei 's/pub fn rust_helper_([a-zA-Z0-9_]*)/#[link_name="rust_helper_\1"]\n    pub fn \1/g' $@
+$(obj)/bindings/bindings_helpers_generated.rs: $(src)/helpers.c FORCE
+	$(call if_changed_dep,bindgen)
+
+quiet_cmd_exports = EXPORTS $@
+      cmd_exports = \
+	$(NM) -p --defined-only $< \
+		| grep -E ' (T|R|D) ' | cut -d ' ' -f 3 \
+		| xargs -Isymbol \
+		echo 'EXPORT_SYMBOL_RUST_GPL(symbol);' > $@
+
+$(obj)/exports_core_generated.h: $(obj)/core.o FORCE
+	$(call if_changed,exports)
+
+$(obj)/exports_alloc_generated.h: $(obj)/alloc.o FORCE
+	$(call if_changed,exports)
+
+$(obj)/exports_bindings_generated.h: $(obj)/bindings.o FORCE
+	$(call if_changed,exports)
+
+$(obj)/exports_kernel_generated.h: $(obj)/kernel.o FORCE
+	$(call if_changed,exports)
+
+quiet_cmd_rustc_procmacro = $(RUSTC_OR_CLIPPY_QUIET) P $@
+      cmd_rustc_procmacro = \
+	$(RUSTC_OR_CLIPPY) $(rust_common_flags) \
+		--emit=dep-info,link --extern proc_macro \
+		--crate-type proc-macro --out-dir $(objtree)/$(obj) \
+		--crate-name $(patsubst lib%.so,%,$(notdir $@)) $<; \
+	mv $(objtree)/$(obj)/$(patsubst lib%.so,%,$(notdir $@)).d $(depfile); \
+	sed -i '/^\#/d' $(depfile)
+
+# Procedural macros can only be used with the `rustc` that compiled it.
+# Therefore, to get `libmacros.so` automatically recompiled when the compiler
+# version changes, we add `core.o` as a dependency (even if it is not needed).
+$(obj)/libmacros.so: $(src)/macros/lib.rs $(obj)/core.o FORCE
+	$(call if_changed_dep,rustc_procmacro)
+
+quiet_cmd_rustc_library = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) L $@
+      cmd_rustc_library = \
+	OBJTREE=$(abspath $(objtree)) \
+	$(if $(skip_clippy),$(RUSTC),$(RUSTC_OR_CLIPPY)) \
+		$(filter-out $(skip_flags),$(rust_flags) $(rustc_target_flags)) \
+		--emit=dep-info,obj,metadata --crate-type rlib \
+		--out-dir $(objtree)/$(obj) -L$(objtree)/$(obj) \
+		--crate-name $(patsubst %.o,%,$(notdir $@)) $<; \
+	mv $(objtree)/$(obj)/$(patsubst %.o,%,$(notdir $@)).d $(depfile); \
+	sed -i '/^\#/d' $(depfile) \
+	$(if $(rustc_objcopy),;$(OBJCOPY) $(rustc_objcopy) $@)
+
+rust-analyzer:
+	$(Q)$(srctree)/scripts/generate_rust_analyzer.py $(srctree) $(objtree) \
+		$(RUST_LIB_SRC) > $(objtree)/rust-project.json
+
+$(obj)/core.o: private skip_clippy = 1
+$(obj)/core.o: private skip_flags = -Dunreachable_pub
+$(obj)/core.o: private rustc_target_flags = $(core-cfgs)
+$(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs $(obj)/target.json FORCE
+	$(call if_changed_dep,rustc_library)
+
+$(obj)/compiler_builtins.o: private rustc_objcopy = -w -W '__*'
+$(obj)/compiler_builtins.o: $(src)/compiler_builtins.rs $(obj)/core.o FORCE
+	$(call if_changed_dep,rustc_library)
+
+$(obj)/alloc.o: private skip_clippy = 1
+$(obj)/alloc.o: private skip_flags = -Dunreachable_pub
+$(obj)/alloc.o: private rustc_target_flags = $(alloc-cfgs)
+$(obj)/alloc.o: $(src)/alloc/lib.rs $(obj)/compiler_builtins.o FORCE
+	$(call if_changed_dep,rustc_library)
+
+$(obj)/build_error.o: $(src)/build_error.rs $(obj)/compiler_builtins.o FORCE
+	$(call if_changed_dep,rustc_library)
+
+$(obj)/bindings.o: $(src)/bindings/lib.rs \
+    $(obj)/compiler_builtins.o \
+    $(obj)/bindings/bindings_generated.rs \
+    $(obj)/bindings/bindings_helpers_generated.rs FORCE
+	$(call if_changed_dep,rustc_library)
+
+$(obj)/kernel.o: private rustc_target_flags = --extern alloc \
+    --extern build_error --extern macros --extern bindings
+$(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o $(obj)/build_error.o \
+    $(obj)/libmacros.so $(obj)/bindings.o FORCE
+	$(call if_changed_dep,rustc_library)
+
+endif # CONFIG_RUST
diff --git a/rust/alloc/README.md b/rust/alloc/README.md
new file mode 100644
index 000000000000..c89c753720b5
--- /dev/null
+++ b/rust/alloc/README.md
@@ -0,0 +1,33 @@
+# `alloc`
+
+These source files come from the Rust standard library, hosted in
+the <https://github.com/rust-lang/rust> repository, licensed under
+"Apache-2.0 OR MIT" and adapted for kernel use. For copyright details,
+see <https://github.com/rust-lang/rust/blob/master/COPYRIGHT>.
+
+Please note that these files should be kept as close as possible to
+upstream. In general, only additions should be performed (e.g. new
+methods). Eventually, changes should make it into upstream so that,
+at some point, this fork can be dropped from the kernel tree.
+
+
+## Rationale
+
+On one hand, kernel folks wanted to keep `alloc` in-tree to have more
+freedom in both workflow and actual features if actually needed
+(e.g. receiver types if we ended up using them), which is reasonable.
+
+On the other hand, Rust folks wanted to keep `alloc` as close as
+upstream as possible and avoid as much divergence as possible, which
+is also reasonable.
+
+We agreed on a middle-ground: we would keep a subset of `alloc`
+in-tree that would be as small and as close as possible to upstream.
+Then, upstream can start adding the functions that we add to `alloc`
+etc., until we reach a point where the kernel already knows exactly
+what it needs in `alloc` and all the new methods are merged into
+upstream, so that we can drop `alloc` from the kernel tree and go back
+to using the upstream one.
+
+By doing this, the kernel can go a bit faster now, and Rust can
+slowly incorporate and discuss the changes as needed.
diff --git a/rust/alloc/alloc.rs b/rust/alloc/alloc.rs
new file mode 100644
index 000000000000..ca224a541770
--- /dev/null
+++ b/rust/alloc/alloc.rs
@@ -0,0 +1,440 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! Memory allocation APIs
+
+#![stable(feature = "alloc_module", since = "1.28.0")]
+
+#[cfg(not(test))]
+use core::intrinsics;
+use core::intrinsics::{min_align_of_val, size_of_val};
+
+use core::ptr::Unique;
+#[cfg(not(test))]
+use core::ptr::{self, NonNull};
+
+#[stable(feature = "alloc_module", since = "1.28.0")]
+#[doc(inline)]
+pub use core::alloc::*;
+
+use core::marker::Destruct;
+
+#[cfg(test)]
+mod tests;
+
+extern "Rust" {
+    // These are the magic symbols to call the global allocator.  rustc generates
+    // them to call `__rg_alloc` etc. if there is a `#[global_allocator]` attribute
+    // (the code expanding that attribute macro generates those functions), or to call
+    // the default implementations in libstd (`__rdl_alloc` etc. in `library/std/src/alloc.rs`)
+    // otherwise.
+    // The rustc fork of LLVM also special-cases these function names to be able to optimize them
+    // like `malloc`, `realloc`, and `free`, respectively.
+    #[rustc_allocator]
+    #[rustc_allocator_nounwind]
+    fn __rust_alloc(size: usize, align: usize) -> *mut u8;
+    #[rustc_allocator_nounwind]
+    fn __rust_dealloc(ptr: *mut u8, size: usize, align: usize);
+    #[rustc_allocator_nounwind]
+    fn __rust_realloc(ptr: *mut u8, old_size: usize, align: usize, new_size: usize) -> *mut u8;
+    #[rustc_allocator_nounwind]
+    fn __rust_alloc_zeroed(size: usize, align: usize) -> *mut u8;
+}
+
+/// The global memory allocator.
+///
+/// This type implements the [`Allocator`] trait by forwarding calls
+/// to the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// Note: while this type is unstable, the functionality it provides can be
+/// accessed through the [free functions in `alloc`](self#functions).
+#[unstable(feature = "allocator_api", issue = "32838")]
+#[derive(Copy, Clone, Default, Debug)]
+#[cfg(not(test))]
+pub struct Global;
+
+#[cfg(test)]
+pub use std::alloc::Global;
+
+/// Allocate memory with the global allocator.
+///
+/// This function forwards calls to the [`GlobalAlloc::alloc`] method
+/// of the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// This function is expected to be deprecated in favor of the `alloc` method
+/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
+///
+/// # Safety
+///
+/// See [`GlobalAlloc::alloc`].
+///
+/// # Examples
+///
+/// ```
+/// use std::alloc::{alloc, dealloc, Layout};
+///
+/// unsafe {
+///     let layout = Layout::new::<u16>();
+///     let ptr = alloc(layout);
+///
+///     *(ptr as *mut u16) = 42;
+///     assert_eq!(*(ptr as *mut u16), 42);
+///
+///     dealloc(ptr, layout);
+/// }
+/// ```
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[must_use = "losing the pointer will leak memory"]
+#[inline]
+pub unsafe fn alloc(layout: Layout) -> *mut u8 {
+    unsafe { __rust_alloc(layout.size(), layout.align()) }
+}
+
+/// Deallocate memory with the global allocator.
+///
+/// This function forwards calls to the [`GlobalAlloc::dealloc`] method
+/// of the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// This function is expected to be deprecated in favor of the `dealloc` method
+/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
+///
+/// # Safety
+///
+/// See [`GlobalAlloc::dealloc`].
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[inline]
+pub unsafe fn dealloc(ptr: *mut u8, layout: Layout) {
+    unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
+}
+
+/// Reallocate memory with the global allocator.
+///
+/// This function forwards calls to the [`GlobalAlloc::realloc`] method
+/// of the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// This function is expected to be deprecated in favor of the `realloc` method
+/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
+///
+/// # Safety
+///
+/// See [`GlobalAlloc::realloc`].
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[must_use = "losing the pointer will leak memory"]
+#[inline]
+pub unsafe fn realloc(ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+    unsafe { __rust_realloc(ptr, layout.size(), layout.align(), new_size) }
+}
+
+/// Allocate zero-initialized memory with the global allocator.
+///
+/// This function forwards calls to the [`GlobalAlloc::alloc_zeroed`] method
+/// of the allocator registered with the `#[global_allocator]` attribute
+/// if there is one, or the `std` crate’s default.
+///
+/// This function is expected to be deprecated in favor of the `alloc_zeroed` method
+/// of the [`Global`] type when it and the [`Allocator`] trait become stable.
+///
+/// # Safety
+///
+/// See [`GlobalAlloc::alloc_zeroed`].
+///
+/// # Examples
+///
+/// ```
+/// use std::alloc::{alloc_zeroed, dealloc, Layout};
+///
+/// unsafe {
+///     let layout = Layout::new::<u16>();
+///     let ptr = alloc_zeroed(layout);
+///
+///     assert_eq!(*(ptr as *mut u16), 0);
+///
+///     dealloc(ptr, layout);
+/// }
+/// ```
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[must_use = "losing the pointer will leak memory"]
+#[inline]
+pub unsafe fn alloc_zeroed(layout: Layout) -> *mut u8 {
+    unsafe { __rust_alloc_zeroed(layout.size(), layout.align()) }
+}
+
+#[cfg(not(test))]
+impl Global {
+    #[inline]
+    fn alloc_impl(&self, layout: Layout, zeroed: bool) -> Result<NonNull<[u8]>, AllocError> {
+        match layout.size() {
+            0 => Ok(NonNull::slice_from_raw_parts(layout.dangling(), 0)),
+            // SAFETY: `layout` is non-zero in size,
+            size => unsafe {
+                let raw_ptr = if zeroed { alloc_zeroed(layout) } else { alloc(layout) };
+                let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
+                Ok(NonNull::slice_from_raw_parts(ptr, size))
+            },
+        }
+    }
+
+    // SAFETY: Same as `Allocator::grow`
+    #[inline]
+    unsafe fn grow_impl(
+        &self,
+        ptr: NonNull<u8>,
+        old_layout: Layout,
+        new_layout: Layout,
+        zeroed: bool,
+    ) -> Result<NonNull<[u8]>, AllocError> {
+        debug_assert!(
+            new_layout.size() >= old_layout.size(),
+            "`new_layout.size()` must be greater than or equal to `old_layout.size()`"
+        );
+
+        match old_layout.size() {
+            0 => self.alloc_impl(new_layout, zeroed),
+
+            // SAFETY: `new_size` is non-zero as `old_size` is greater than or equal to `new_size`
+            // as required by safety conditions. Other conditions must be upheld by the caller
+            old_size if old_layout.align() == new_layout.align() => unsafe {
+                let new_size = new_layout.size();
+
+                // `realloc` probably checks for `new_size >= old_layout.size()` or something similar.
+                intrinsics::assume(new_size >= old_layout.size());
+
+                let raw_ptr = realloc(ptr.as_ptr(), old_layout, new_size);
+                let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
+                if zeroed {
+                    raw_ptr.add(old_size).write_bytes(0, new_size - old_size);
+                }
+                Ok(NonNull::slice_from_raw_parts(ptr, new_size))
+            },
+
+            // SAFETY: because `new_layout.size()` must be greater than or equal to `old_size`,
+            // both the old and new memory allocation are valid for reads and writes for `old_size`
+            // bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
+            // `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
+            // for `dealloc` must be upheld by the caller.
+            old_size => unsafe {
+                let new_ptr = self.alloc_impl(new_layout, zeroed)?;
+                ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), old_size);
+                self.deallocate(ptr, old_layout);
+                Ok(new_ptr)
+            },
+        }
+    }
+}
+
+#[unstable(feature = "allocator_api", issue = "32838")]
+#[cfg(not(test))]
+unsafe impl Allocator for Global {
+    #[inline]
+    fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+        self.alloc_impl(layout, false)
+    }
+
+    #[inline]
+    fn allocate_zeroed(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError> {
+        self.alloc_impl(layout, true)
+    }
+
+    #[inline]
+    unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) {
+        if layout.size() != 0 {
+            // SAFETY: `layout` is non-zero in size,
+            // other conditions must be upheld by the caller
+            unsafe { dealloc(ptr.as_ptr(), layout) }
+        }
+    }
+
+    #[inline]
+    unsafe fn grow(
+        &self,
+        ptr: NonNull<u8>,
+        old_layout: Layout,
+        new_layout: Layout,
+    ) -> Result<NonNull<[u8]>, AllocError> {
+        // SAFETY: all conditions must be upheld by the caller
+        unsafe { self.grow_impl(ptr, old_layout, new_layout, false) }
+    }
+
+    #[inline]
+    unsafe fn grow_zeroed(
+        &self,
+        ptr: NonNull<u8>,
+        old_layout: Layout,
+        new_layout: Layout,
+    ) -> Result<NonNull<[u8]>, AllocError> {
+        // SAFETY: all conditions must be upheld by the caller
+        unsafe { self.grow_impl(ptr, old_layout, new_layout, true) }
+    }
+
+    #[inline]
+    unsafe fn shrink(
+        &self,
+        ptr: NonNull<u8>,
+        old_layout: Layout,
+        new_layout: Layout,
+    ) -> Result<NonNull<[u8]>, AllocError> {
+        debug_assert!(
+            new_layout.size() <= old_layout.size(),
+            "`new_layout.size()` must be smaller than or equal to `old_layout.size()`"
+        );
+
+        match new_layout.size() {
+            // SAFETY: conditions must be upheld by the caller
+            0 => unsafe {
+                self.deallocate(ptr, old_layout);
+                Ok(NonNull::slice_from_raw_parts(new_layout.dangling(), 0))
+            },
+
+            // SAFETY: `new_size` is non-zero. Other conditions must be upheld by the caller
+            new_size if old_layout.align() == new_layout.align() => unsafe {
+                // `realloc` probably checks for `new_size <= old_layout.size()` or something similar.
+                intrinsics::assume(new_size <= old_layout.size());
+
+                let raw_ptr = realloc(ptr.as_ptr(), old_layout, new_size);
+                let ptr = NonNull::new(raw_ptr).ok_or(AllocError)?;
+                Ok(NonNull::slice_from_raw_parts(ptr, new_size))
+            },
+
+            // SAFETY: because `new_size` must be smaller than or equal to `old_layout.size()`,
+            // both the old and new memory allocation are valid for reads and writes for `new_size`
+            // bytes. Also, because the old allocation wasn't yet deallocated, it cannot overlap
+            // `new_ptr`. Thus, the call to `copy_nonoverlapping` is safe. The safety contract
+            // for `dealloc` must be upheld by the caller.
+            new_size => unsafe {
+                let new_ptr = self.allocate(new_layout)?;
+                ptr::copy_nonoverlapping(ptr.as_ptr(), new_ptr.as_mut_ptr(), new_size);
+                self.deallocate(ptr, old_layout);
+                Ok(new_ptr)
+            },
+        }
+    }
+}
+
+/// The allocator for unique pointers.
+#[cfg(all(not(no_global_oom_handling), not(test)))]
+#[lang = "exchange_malloc"]
+#[inline]
+unsafe fn exchange_malloc(size: usize, align: usize) -> *mut u8 {
+    let layout = unsafe { Layout::from_size_align_unchecked(size, align) };
+    match Global.allocate(layout) {
+        Ok(ptr) => ptr.as_mut_ptr(),
+        Err(_) => handle_alloc_error(layout),
+    }
+}
+
+#[cfg_attr(not(test), lang = "box_free")]
+#[inline]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+// This signature has to be the same as `Box`, otherwise an ICE will happen.
+// When an additional parameter to `Box` is added (like `A: Allocator`), this has to be added here as
+// well.
+// For example if `Box` is changed to  `struct Box<T: ?Sized, A: Allocator>(Unique<T>, A)`,
+// this function has to be changed to `fn box_free<T: ?Sized, A: Allocator>(Unique<T>, A)` as well.
+pub(crate) const unsafe fn box_free<T: ?Sized, A: ~const Allocator + ~const Destruct>(
+    ptr: Unique<T>,
+    alloc: A,
+) {
+    unsafe {
+        let size = size_of_val(ptr.as_ref());
+        let align = min_align_of_val(ptr.as_ref());
+        let layout = Layout::from_size_align_unchecked(size, align);
+        alloc.deallocate(From::from(ptr.cast()), layout)
+    }
+}
+
+// # Allocation error handler
+
+#[cfg(not(no_global_oom_handling))]
+extern "Rust" {
+    // This is the magic symbol to call the global alloc error handler.  rustc generates
+    // it to call `__rg_oom` if there is a `#[alloc_error_handler]`, or to call the
+    // default implementations below (`__rdl_oom`) otherwise.
+    fn __rust_alloc_error_handler(size: usize, align: usize) -> !;
+}
+
+/// Abort on memory allocation error or failure.
+///
+/// Callers of memory allocation APIs wishing to abort computation
+/// in response to an allocation error are encouraged to call this function,
+/// rather than directly invoking `panic!` or similar.
+///
+/// The default behavior of this function is to print a message to standard error
+/// and abort the process.
+/// It can be replaced with [`set_alloc_error_hook`] and [`take_alloc_error_hook`].
+///
+/// [`set_alloc_error_hook`]: ../../std/alloc/fn.set_alloc_error_hook.html
+/// [`take_alloc_error_hook`]: ../../std/alloc/fn.take_alloc_error_hook.html
+#[stable(feature = "global_alloc", since = "1.28.0")]
+#[rustc_const_unstable(feature = "const_alloc_error", issue = "92523")]
+#[cfg(all(not(no_global_oom_handling), not(test)))]
+#[cold]
+pub const fn handle_alloc_error(layout: Layout) -> ! {
+    const fn ct_error(_: Layout) -> ! {
+        panic!("allocation failed");
+    }
+
+    fn rt_error(layout: Layout) -> ! {
+        unsafe {
+            __rust_alloc_error_handler(layout.size(), layout.align());
+        }
+    }
+
+    unsafe { core::intrinsics::const_eval_select((layout,), ct_error, rt_error) }
+}
+
+// For alloc test `std::alloc::handle_alloc_error` can be used directly.
+#[cfg(all(not(no_global_oom_handling), test))]
+pub use std::alloc::handle_alloc_error;
+
+#[cfg(all(not(no_global_oom_handling), not(test)))]
+#[doc(hidden)]
+#[allow(unused_attributes)]
+#[unstable(feature = "alloc_internals", issue = "none")]
+pub mod __alloc_error_handler {
+    use crate::alloc::Layout;
+
+    // called via generated `__rust_alloc_error_handler`
+
+    // if there is no `#[alloc_error_handler]`
+    #[rustc_std_internal_symbol]
+    pub unsafe extern "C-unwind" fn __rdl_oom(size: usize, _align: usize) -> ! {
+        panic!("memory allocation of {size} bytes failed")
+    }
+
+    // if there is an `#[alloc_error_handler]`
+    #[rustc_std_internal_symbol]
+    pub unsafe extern "C-unwind" fn __rg_oom(size: usize, align: usize) -> ! {
+        let layout = unsafe { Layout::from_size_align_unchecked(size, align) };
+        extern "Rust" {
+            #[lang = "oom"]
+            fn oom_impl(layout: Layout) -> !;
+        }
+        unsafe { oom_impl(layout) }
+    }
+}
+
+/// Specialize clones into pre-allocated, uninitialized memory.
+/// Used by `Box::clone` and `Rc`/`Arc::make_mut`.
+pub(crate) trait WriteCloneIntoRaw: Sized {
+    unsafe fn write_clone_into_raw(&self, target: *mut Self);
+}
+
+impl<T: Clone> WriteCloneIntoRaw for T {
+    #[inline]
+    default unsafe fn write_clone_into_raw(&self, target: *mut Self) {
+        // Having allocated *first* may allow the optimizer to create
+        // the cloned value in-place, skipping the local and move.
+        unsafe { target.write(self.clone()) };
+    }
+}
+
+impl<T: Copy> WriteCloneIntoRaw for T {
+    #[inline]
+    unsafe fn write_clone_into_raw(&self, target: *mut Self) {
+        // We can always copy in-place, without ever involving a local value.
+        unsafe { target.copy_from_nonoverlapping(self, 1) };
+    }
+}
diff --git a/rust/alloc/borrow.rs b/rust/alloc/borrow.rs
new file mode 100644
index 000000000000..ca8e3dfa7004
--- /dev/null
+++ b/rust/alloc/borrow.rs
@@ -0,0 +1,498 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! A module for working with borrowed data.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use core::cmp::Ordering;
+use core::hash::{Hash, Hasher};
+use core::ops::Deref;
+#[cfg(not(no_global_oom_handling))]
+use core::ops::{Add, AddAssign};
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::borrow::{Borrow, BorrowMut};
+
+use crate::fmt;
+#[cfg(not(no_global_oom_handling))]
+use crate::string::String;
+
+use Cow::*;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: ?Sized> Borrow<B> for Cow<'a, B>
+where
+    B: ToOwned,
+    <B as ToOwned>::Owned: 'a,
+{
+    fn borrow(&self) -> &B {
+        &**self
+    }
+}
+
+/// A generalization of `Clone` to borrowed data.
+///
+/// Some types make it possible to go from borrowed to owned, usually by
+/// implementing the `Clone` trait. But `Clone` works only for going from `&T`
+/// to `T`. The `ToOwned` trait generalizes `Clone` to construct owned data
+/// from any borrow of a given type.
+#[cfg_attr(not(test), rustc_diagnostic_item = "ToOwned")]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait ToOwned {
+    /// The resulting type after obtaining ownership.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    type Owned: Borrow<Self>;
+
+    /// Creates owned data from borrowed data, usually by cloning.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s: &str = "a";
+    /// let ss: String = s.to_owned();
+    ///
+    /// let v: &[i32] = &[1, 2];
+    /// let vv: Vec<i32> = v.to_owned();
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use = "cloning is often expensive and is not expected to have side effects"]
+    fn to_owned(&self) -> Self::Owned;
+
+    /// Uses borrowed data to replace owned data, usually by cloning.
+    ///
+    /// This is borrow-generalized version of `Clone::clone_from`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// # #![feature(toowned_clone_into)]
+    /// let mut s: String = String::new();
+    /// "hello".clone_into(&mut s);
+    ///
+    /// let mut v: Vec<i32> = Vec::new();
+    /// [1, 2][..].clone_into(&mut v);
+    /// ```
+    #[unstable(feature = "toowned_clone_into", reason = "recently added", issue = "41263")]
+    fn clone_into(&self, target: &mut Self::Owned) {
+        *target = self.to_owned();
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> ToOwned for T
+where
+    T: Clone,
+{
+    type Owned = T;
+    fn to_owned(&self) -> T {
+        self.clone()
+    }
+
+    fn clone_into(&self, target: &mut T) {
+        target.clone_from(self);
+    }
+}
+
+/// A clone-on-write smart pointer.
+///
+/// The type `Cow` is a smart pointer providing clone-on-write functionality: it
+/// can enclose and provide immutable access to borrowed data, and clone the
+/// data lazily when mutation or ownership is required. The type is designed to
+/// work with general borrowed data via the `Borrow` trait.
+///
+/// `Cow` implements `Deref`, which means that you can call
+/// non-mutating methods directly on the data it encloses. If mutation
+/// is desired, `to_mut` will obtain a mutable reference to an owned
+/// value, cloning if necessary.
+///
+/// If you need reference-counting pointers, note that
+/// [`Rc::make_mut`][crate::rc::Rc::make_mut] and
+/// [`Arc::make_mut`][crate::sync::Arc::make_mut] can provide clone-on-write
+/// functionality as well.
+///
+/// # Examples
+///
+/// ```
+/// use std::borrow::Cow;
+///
+/// fn abs_all(input: &mut Cow<[i32]>) {
+///     for i in 0..input.len() {
+///         let v = input[i];
+///         if v < 0 {
+///             // Clones into a vector if not already owned.
+///             input.to_mut()[i] = -v;
+///         }
+///     }
+/// }
+///
+/// // No clone occurs because `input` doesn't need to be mutated.
+/// let slice = [0, 1, 2];
+/// let mut input = Cow::from(&slice[..]);
+/// abs_all(&mut input);
+///
+/// // Clone occurs because `input` needs to be mutated.
+/// let slice = [-1, 0, 1];
+/// let mut input = Cow::from(&slice[..]);
+/// abs_all(&mut input);
+///
+/// // No clone occurs because `input` is already owned.
+/// let mut input = Cow::from(vec![-1, 0, 1]);
+/// abs_all(&mut input);
+/// ```
+///
+/// Another example showing how to keep `Cow` in a struct:
+///
+/// ```
+/// use std::borrow::Cow;
+///
+/// struct Items<'a, X: 'a> where [X]: ToOwned<Owned = Vec<X>> {
+///     values: Cow<'a, [X]>,
+/// }
+///
+/// impl<'a, X: Clone + 'a> Items<'a, X> where [X]: ToOwned<Owned = Vec<X>> {
+///     fn new(v: Cow<'a, [X]>) -> Self {
+///         Items { values: v }
+///     }
+/// }
+///
+/// // Creates a container from borrowed values of a slice
+/// let readonly = [1, 2];
+/// let borrowed = Items::new((&readonly[..]).into());
+/// match borrowed {
+///     Items { values: Cow::Borrowed(b) } => println!("borrowed {b:?}"),
+///     _ => panic!("expect borrowed value"),
+/// }
+///
+/// let mut clone_on_write = borrowed;
+/// // Mutates the data from slice into owned vec and pushes a new value on top
+/// clone_on_write.values.to_mut().push(3);
+/// println!("clone_on_write = {:?}", clone_on_write.values);
+///
+/// // The data was mutated. Let's check it out.
+/// match clone_on_write {
+///     Items { values: Cow::Owned(_) } => println!("clone_on_write contains owned data"),
+///     _ => panic!("expect owned data"),
+/// }
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Cow")]
+pub enum Cow<'a, B: ?Sized + 'a>
+where
+    B: ToOwned,
+{
+    /// Borrowed data.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Borrowed(#[stable(feature = "rust1", since = "1.0.0")] &'a B),
+
+    /// Owned data.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    Owned(#[stable(feature = "rust1", since = "1.0.0")] <B as ToOwned>::Owned),
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized + ToOwned> Clone for Cow<'_, B> {
+    fn clone(&self) -> Self {
+        match *self {
+            Borrowed(b) => Borrowed(b),
+            Owned(ref o) => {
+                let b: &B = o.borrow();
+                Owned(b.to_owned())
+            }
+        }
+    }
+
+    fn clone_from(&mut self, source: &Self) {
+        match (self, source) {
+            (&mut Owned(ref mut dest), &Owned(ref o)) => o.borrow().clone_into(dest),
+            (t, s) => *t = s.clone(),
+        }
+    }
+}
+
+impl<B: ?Sized + ToOwned> Cow<'_, B> {
+    /// Returns true if the data is borrowed, i.e. if `to_mut` would require additional work.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(cow_is_borrowed)]
+    /// use std::borrow::Cow;
+    ///
+    /// let cow = Cow::Borrowed("moo");
+    /// assert!(cow.is_borrowed());
+    ///
+    /// let bull: Cow<'_, str> = Cow::Owned("...moo?".to_string());
+    /// assert!(!bull.is_borrowed());
+    /// ```
+    #[unstable(feature = "cow_is_borrowed", issue = "65143")]
+    #[rustc_const_unstable(feature = "const_cow_is_borrowed", issue = "65143")]
+    pub const fn is_borrowed(&self) -> bool {
+        match *self {
+            Borrowed(_) => true,
+            Owned(_) => false,
+        }
+    }
+
+    /// Returns true if the data is owned, i.e. if `to_mut` would be a no-op.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(cow_is_borrowed)]
+    /// use std::borrow::Cow;
+    ///
+    /// let cow: Cow<'_, str> = Cow::Owned("moo".to_string());
+    /// assert!(cow.is_owned());
+    ///
+    /// let bull = Cow::Borrowed("...moo?");
+    /// assert!(!bull.is_owned());
+    /// ```
+    #[unstable(feature = "cow_is_borrowed", issue = "65143")]
+    #[rustc_const_unstable(feature = "const_cow_is_borrowed", issue = "65143")]
+    pub const fn is_owned(&self) -> bool {
+        !self.is_borrowed()
+    }
+
+    /// Acquires a mutable reference to the owned form of the data.
+    ///
+    /// Clones the data if it is not already owned.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::borrow::Cow;
+    ///
+    /// let mut cow = Cow::Borrowed("foo");
+    /// cow.to_mut().make_ascii_uppercase();
+    ///
+    /// assert_eq!(
+    ///   cow,
+    ///   Cow::Owned(String::from("FOO")) as Cow<str>
+    /// );
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn to_mut(&mut self) -> &mut <B as ToOwned>::Owned {
+        match *self {
+            Borrowed(borrowed) => {
+                *self = Owned(borrowed.to_owned());
+                match *self {
+                    Borrowed(..) => unreachable!(),
+                    Owned(ref mut owned) => owned,
+                }
+            }
+            Owned(ref mut owned) => owned,
+        }
+    }
+
+    /// Extracts the owned data.
+    ///
+    /// Clones the data if it is not already owned.
+    ///
+    /// # Examples
+    ///
+    /// Calling `into_owned` on a `Cow::Borrowed` returns a clone of the borrowed data:
+    ///
+    /// ```
+    /// use std::borrow::Cow;
+    ///
+    /// let s = "Hello world!";
+    /// let cow = Cow::Borrowed(s);
+    ///
+    /// assert_eq!(
+    ///   cow.into_owned(),
+    ///   String::from(s)
+    /// );
+    /// ```
+    ///
+    /// Calling `into_owned` on a `Cow::Owned` returns the owned data. The data is moved out of the
+    /// `Cow` without being cloned.
+    ///
+    /// ```
+    /// use std::borrow::Cow;
+    ///
+    /// let s = "Hello world!";
+    /// let cow: Cow<str> = Cow::Owned(String::from(s));
+    ///
+    /// assert_eq!(
+    ///   cow.into_owned(),
+    ///   String::from(s)
+    /// );
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_owned(self) -> <B as ToOwned>::Owned {
+        match self {
+            Borrowed(borrowed) => borrowed.to_owned(),
+            Owned(owned) => owned,
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_deref", issue = "88955")]
+impl<B: ?Sized + ToOwned> const Deref for Cow<'_, B>
+where
+    B::Owned: ~const Borrow<B>,
+{
+    type Target = B;
+
+    fn deref(&self) -> &B {
+        match *self {
+            Borrowed(borrowed) => borrowed,
+            Owned(ref owned) => owned.borrow(),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> Eq for Cow<'_, B> where B: Eq + ToOwned {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> Ord for Cow<'_, B>
+where
+    B: Ord + ToOwned,
+{
+    #[inline]
+    fn cmp(&self, other: &Self) -> Ordering {
+        Ord::cmp(&**self, &**other)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, 'b, B: ?Sized, C: ?Sized> PartialEq<Cow<'b, C>> for Cow<'a, B>
+where
+    B: PartialEq<C> + ToOwned,
+    C: ToOwned,
+{
+    #[inline]
+    fn eq(&self, other: &Cow<'b, C>) -> bool {
+        PartialEq::eq(&**self, &**other)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, B: ?Sized> PartialOrd for Cow<'a, B>
+where
+    B: PartialOrd + ToOwned,
+{
+    #[inline]
+    fn partial_cmp(&self, other: &Cow<'a, B>) -> Option<Ordering> {
+        PartialOrd::partial_cmp(&**self, &**other)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> fmt::Debug for Cow<'_, B>
+where
+    B: fmt::Debug + ToOwned<Owned: fmt::Debug>,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            Borrowed(ref b) => fmt::Debug::fmt(b, f),
+            Owned(ref o) => fmt::Debug::fmt(o, f),
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> fmt::Display for Cow<'_, B>
+where
+    B: fmt::Display + ToOwned<Owned: fmt::Display>,
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match *self {
+            Borrowed(ref b) => fmt::Display::fmt(b, f),
+            Owned(ref o) => fmt::Display::fmt(o, f),
+        }
+    }
+}
+
+#[stable(feature = "default", since = "1.11.0")]
+impl<B: ?Sized> Default for Cow<'_, B>
+where
+    B: ToOwned<Owned: Default>,
+{
+    /// Creates an owned Cow<'a, B> with the default value for the contained owned value.
+    fn default() -> Self {
+        Owned(<B as ToOwned>::Owned::default())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<B: ?Sized> Hash for Cow<'_, B>
+where
+    B: Hash + ToOwned,
+{
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        Hash::hash(&**self, state)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + ToOwned> AsRef<T> for Cow<'_, T> {
+    fn as_ref(&self) -> &T {
+        self
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_add", since = "1.14.0")]
+impl<'a> Add<&'a str> for Cow<'a, str> {
+    type Output = Cow<'a, str>;
+
+    #[inline]
+    fn add(mut self, rhs: &'a str) -> Self::Output {
+        self += rhs;
+        self
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_add", since = "1.14.0")]
+impl<'a> Add<Cow<'a, str>> for Cow<'a, str> {
+    type Output = Cow<'a, str>;
+
+    #[inline]
+    fn add(mut self, rhs: Cow<'a, str>) -> Self::Output {
+        self += rhs;
+        self
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_add", since = "1.14.0")]
+impl<'a> AddAssign<&'a str> for Cow<'a, str> {
+    fn add_assign(&mut self, rhs: &'a str) {
+        if self.is_empty() {
+            *self = Cow::Borrowed(rhs)
+        } else if !rhs.is_empty() {
+            if let Cow::Borrowed(lhs) = *self {
+                let mut s = String::with_capacity(lhs.len() + rhs.len());
+                s.push_str(lhs);
+                *self = Cow::Owned(s);
+            }
+            self.to_mut().push_str(rhs);
+        }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_add", since = "1.14.0")]
+impl<'a> AddAssign<Cow<'a, str>> for Cow<'a, str> {
+    fn add_assign(&mut self, rhs: Cow<'a, str>) {
+        if self.is_empty() {
+            *self = rhs
+        } else if !rhs.is_empty() {
+            if let Cow::Borrowed(lhs) = *self {
+                let mut s = String::with_capacity(lhs.len() + rhs.len());
+                s.push_str(lhs);
+                *self = Cow::Owned(s);
+            }
+            self.to_mut().push_str(&rhs);
+        }
+    }
+}
diff --git a/rust/alloc/boxed.rs b/rust/alloc/boxed.rs
new file mode 100644
index 000000000000..8fd296421dec
--- /dev/null
+++ b/rust/alloc/boxed.rs
@@ -0,0 +1,2026 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! A pointer type for heap allocation.
+//!
+//! [`Box<T>`], casually referred to as a 'box', provides the simplest form of
+//! heap allocation in Rust. Boxes provide ownership for this allocation, and
+//! drop their contents when they go out of scope. Boxes also ensure that they
+//! never allocate more than `isize::MAX` bytes.
+//!
+//! # Examples
+//!
+//! Move a value from the stack to the heap by creating a [`Box`]:
+//!
+//! ```
+//! let val: u8 = 5;
+//! let boxed: Box<u8> = Box::new(val);
+//! ```
+//!
+//! Move a value from a [`Box`] back to the stack by [dereferencing]:
+//!
+//! ```
+//! let boxed: Box<u8> = Box::new(5);
+//! let val: u8 = *boxed;
+//! ```
+//!
+//! Creating a recursive data structure:
+//!
+//! ```
+//! #[derive(Debug)]
+//! enum List<T> {
+//!     Cons(T, Box<List<T>>),
+//!     Nil,
+//! }
+//!
+//! let list: List<i32> = List::Cons(1, Box::new(List::Cons(2, Box::new(List::Nil))));
+//! println!("{list:?}");
+//! ```
+//!
+//! This will print `Cons(1, Cons(2, Nil))`.
+//!
+//! Recursive structures must be boxed, because if the definition of `Cons`
+//! looked like this:
+//!
+//! ```compile_fail,E0072
+//! # enum List<T> {
+//! Cons(T, List<T>),
+//! # }
+//! ```
+//!
+//! It wouldn't work. This is because the size of a `List` depends on how many
+//! elements are in the list, and so we don't know how much memory to allocate
+//! for a `Cons`. By introducing a [`Box<T>`], which has a defined size, we know how
+//! big `Cons` needs to be.
+//!
+//! # Memory layout
+//!
+//! For non-zero-sized values, a [`Box`] will use the [`Global`] allocator for
+//! its allocation. It is valid to convert both ways between a [`Box`] and a
+//! raw pointer allocated with the [`Global`] allocator, given that the
+//! [`Layout`] used with the allocator is correct for the type. More precisely,
+//! a `value: *mut T` that has been allocated with the [`Global`] allocator
+//! with `Layout::for_value(&*value)` may be converted into a box using
+//! [`Box::<T>::from_raw(value)`]. Conversely, the memory backing a `value: *mut
+//! T` obtained from [`Box::<T>::into_raw`] may be deallocated using the
+//! [`Global`] allocator with [`Layout::for_value(&*value)`].
+//!
+//! For zero-sized values, the `Box` pointer still has to be [valid] for reads
+//! and writes and sufficiently aligned. In particular, casting any aligned
+//! non-zero integer literal to a raw pointer produces a valid pointer, but a
+//! pointer pointing into previously allocated memory that since got freed is
+//! not valid. The recommended way to build a Box to a ZST if `Box::new` cannot
+//! be used is to use [`ptr::NonNull::dangling`].
+//!
+//! So long as `T: Sized`, a `Box<T>` is guaranteed to be represented
+//! as a single pointer and is also ABI-compatible with C pointers
+//! (i.e. the C type `T*`). This means that if you have extern "C"
+//! Rust functions that will be called from C, you can define those
+//! Rust functions using `Box<T>` types, and use `T*` as corresponding
+//! type on the C side. As an example, consider this C header which
+//! declares functions that create and destroy some kind of `Foo`
+//! value:
+//!
+//! ```c
+//! /* C header */
+//!
+//! /* Returns ownership to the caller */
+//! struct Foo* foo_new(void);
+//!
+//! /* Takes ownership from the caller; no-op when invoked with null */
+//! void foo_delete(struct Foo*);
+//! ```
+//!
+//! These two functions might be implemented in Rust as follows. Here, the
+//! `struct Foo*` type from C is translated to `Box<Foo>`, which captures
+//! the ownership constraints. Note also that the nullable argument to
+//! `foo_delete` is represented in Rust as `Option<Box<Foo>>`, since `Box<Foo>`
+//! cannot be null.
+//!
+//! ```
+//! #[repr(C)]
+//! pub struct Foo;
+//!
+//! #[no_mangle]
+//! pub extern "C" fn foo_new() -> Box<Foo> {
+//!     Box::new(Foo)
+//! }
+//!
+//! #[no_mangle]
+//! pub extern "C" fn foo_delete(_: Option<Box<Foo>>) {}
+//! ```
+//!
+//! Even though `Box<T>` has the same representation and C ABI as a C pointer,
+//! this does not mean that you can convert an arbitrary `T*` into a `Box<T>`
+//! and expect things to work. `Box<T>` values will always be fully aligned,
+//! non-null pointers. Moreover, the destructor for `Box<T>` will attempt to
+//! free the value with the global allocator. In general, the best practice
+//! is to only use `Box<T>` for pointers that originated from the global
+//! allocator.
+//!
+//! **Important.** At least at present, you should avoid using
+//! `Box<T>` types for functions that are defined in C but invoked
+//! from Rust. In those cases, you should directly mirror the C types
+//! as closely as possible. Using types like `Box<T>` where the C
+//! definition is just using `T*` can lead to undefined behavior, as
+//! described in [rust-lang/unsafe-code-guidelines#198][ucg#198].
+//!
+//! [ucg#198]: https://github.com/rust-lang/unsafe-code-guidelines/issues/198
+//! [dereferencing]: core::ops::Deref
+//! [`Box::<T>::from_raw(value)`]: Box::from_raw
+//! [`Global`]: crate::alloc::Global
+//! [`Layout`]: crate::alloc::Layout
+//! [`Layout::for_value(&*value)`]: crate::alloc::Layout::for_value
+//! [valid]: ptr#safety
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use core::any::Any;
+use core::async_iter::AsyncIterator;
+use core::borrow;
+use core::cmp::Ordering;
+use core::convert::{From, TryFrom};
+use core::fmt;
+use core::future::Future;
+use core::hash::{Hash, Hasher};
+#[cfg(not(no_global_oom_handling))]
+use core::iter::FromIterator;
+use core::iter::{FusedIterator, Iterator};
+use core::marker::{Destruct, Unpin, Unsize};
+use core::mem;
+use core::ops::{
+    CoerceUnsized, Deref, DerefMut, DispatchFromDyn, Generator, GeneratorState, Receiver,
+};
+use core::pin::Pin;
+use core::ptr::{self, Unique};
+use core::task::{Context, Poll};
+
+#[cfg(not(no_global_oom_handling))]
+use crate::alloc::{handle_alloc_error, WriteCloneIntoRaw};
+use crate::alloc::{AllocError, Allocator, Global, Layout};
+#[cfg(not(no_global_oom_handling))]
+use crate::borrow::Cow;
+use crate::raw_vec::RawVec;
+#[cfg(not(no_global_oom_handling))]
+use crate::str::from_boxed_utf8_unchecked;
+#[cfg(not(no_global_oom_handling))]
+use crate::vec::Vec;
+
+#[unstable(feature = "thin_box", issue = "92791")]
+pub use thin::ThinBox;
+
+mod thin;
+
+/// A pointer type for heap allocation.
+///
+/// See the [module-level documentation](../../std/boxed/index.html) for more.
+#[lang = "owned_box"]
+#[fundamental]
+#[stable(feature = "rust1", since = "1.0.0")]
+// The declaration of the `Box` struct must be kept in sync with the
+// `alloc::alloc::box_free` function or ICEs will happen. See the comment
+// on `box_free` for more details.
+pub struct Box<
+    T: ?Sized,
+    #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
+>(Unique<T>, A);
+
+impl<T> Box<T> {
+    /// Allocates memory on the heap and then places `x` into it.
+    ///
+    /// This doesn't actually allocate if `T` is zero-sized.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let five = Box::new(5);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline(always)]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use]
+    pub fn new(x: T) -> Self {
+        box x
+    }
+
+    /// Constructs a new box with uninitialized contents.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let mut five = Box::<u32>::new_uninit();
+    ///
+    /// let five = unsafe {
+    ///     // Deferred initialization:
+    ///     five.as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5)
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[must_use]
+    #[inline]
+    pub fn new_uninit() -> Box<mem::MaybeUninit<T>> {
+        Self::new_uninit_in(Global)
+    }
+
+    /// Constructs a new `Box` with uninitialized contents, with the memory
+    /// being filled with `0` bytes.
+    ///
+    /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+    /// of this method.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let zero = Box::<u32>::new_zeroed();
+    /// let zero = unsafe { zero.assume_init() };
+    ///
+    /// assert_eq!(*zero, 0)
+    /// ```
+    ///
+    /// [zeroed]: mem::MaybeUninit::zeroed
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[must_use]
+    pub fn new_zeroed() -> Box<mem::MaybeUninit<T>> {
+        Self::new_zeroed_in(Global)
+    }
+
+    /// Constructs a new `Pin<Box<T>>`. If `T` does not implement `Unpin`, then
+    /// `x` will be pinned in memory and unable to be moved.
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "pin", since = "1.33.0")]
+    #[must_use]
+    #[inline(always)]
+    pub fn pin(x: T) -> Pin<Box<T>> {
+        (box x).into()
+    }
+
+    /// Allocates memory on the heap then places `x` into it,
+    /// returning an error if the allocation fails
+    ///
+    /// This doesn't actually allocate if `T` is zero-sized.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// let five = Box::try_new(5)?;
+    /// # Ok::<(), std::alloc::AllocError>(())
+    /// ```
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[inline]
+    pub fn try_new(x: T) -> Result<Self, AllocError> {
+        Self::try_new_in(x, Global)
+    }
+
+    /// Constructs a new box with uninitialized contents on the heap,
+    /// returning an error if the allocation fails
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// let mut five = Box::<u32>::try_new_uninit()?;
+    ///
+    /// let five = unsafe {
+    ///     // Deferred initialization:
+    ///     five.as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5);
+    /// # Ok::<(), std::alloc::AllocError>(())
+    /// ```
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    // #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub fn try_new_uninit() -> Result<Box<mem::MaybeUninit<T>>, AllocError> {
+        Box::try_new_uninit_in(Global)
+    }
+
+    /// Constructs a new `Box` with uninitialized contents, with the memory
+    /// being filled with `0` bytes on the heap
+    ///
+    /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+    /// of this method.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// let zero = Box::<u32>::try_new_zeroed()?;
+    /// let zero = unsafe { zero.assume_init() };
+    ///
+    /// assert_eq!(*zero, 0);
+    /// # Ok::<(), std::alloc::AllocError>(())
+    /// ```
+    ///
+    /// [zeroed]: mem::MaybeUninit::zeroed
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    // #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub fn try_new_zeroed() -> Result<Box<mem::MaybeUninit<T>>, AllocError> {
+        Box::try_new_zeroed_in(Global)
+    }
+}
+
+impl<T, A: Allocator> Box<T, A> {
+    /// Allocates memory in the given allocator then places `x` into it.
+    ///
+    /// This doesn't actually allocate if `T` is zero-sized.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let five = Box::new_in(5, System);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[must_use]
+    #[inline]
+    pub const fn new_in(x: T, alloc: A) -> Self
+    where
+        A: ~const Allocator + ~const Destruct,
+    {
+        let mut boxed = Self::new_uninit_in(alloc);
+        unsafe {
+            boxed.as_mut_ptr().write(x);
+            boxed.assume_init()
+        }
+    }
+
+    /// Allocates memory in the given allocator then places `x` into it,
+    /// returning an error if the allocation fails
+    ///
+    /// This doesn't actually allocate if `T` is zero-sized.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let five = Box::try_new_in(5, System)?;
+    /// # Ok::<(), std::alloc::AllocError>(())
+    /// ```
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[inline]
+    pub const fn try_new_in(x: T, alloc: A) -> Result<Self, AllocError>
+    where
+        T: ~const Destruct,
+        A: ~const Allocator + ~const Destruct,
+    {
+        let mut boxed = Self::try_new_uninit_in(alloc)?;
+        unsafe {
+            boxed.as_mut_ptr().write(x);
+            Ok(boxed.assume_init())
+        }
+    }
+
+    /// Constructs a new box with uninitialized contents in the provided allocator.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let mut five = Box::<u32, _>::new_uninit_in(System);
+    ///
+    /// let five = unsafe {
+    ///     // Deferred initialization:
+    ///     five.as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5)
+    /// ```
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[cfg(not(no_global_oom_handling))]
+    #[must_use]
+    // #[unstable(feature = "new_uninit", issue = "63291")]
+    pub const fn new_uninit_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
+    where
+        A: ~const Allocator + ~const Destruct,
+    {
+        let layout = Layout::new::<mem::MaybeUninit<T>>();
+        // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
+        // That would make code size bigger.
+        match Box::try_new_uninit_in(alloc) {
+            Ok(m) => m,
+            Err(_) => handle_alloc_error(layout),
+        }
+    }
+
+    /// Constructs a new box with uninitialized contents in the provided allocator,
+    /// returning an error if the allocation fails
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let mut five = Box::<u32, _>::try_new_uninit_in(System)?;
+    ///
+    /// let five = unsafe {
+    ///     // Deferred initialization:
+    ///     five.as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5);
+    /// # Ok::<(), std::alloc::AllocError>(())
+    /// ```
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    // #[unstable(feature = "new_uninit", issue = "63291")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    pub const fn try_new_uninit_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
+    where
+        A: ~const Allocator + ~const Destruct,
+    {
+        let layout = Layout::new::<mem::MaybeUninit<T>>();
+        let ptr = alloc.allocate(layout)?.cast();
+        unsafe { Ok(Box::from_raw_in(ptr.as_ptr(), alloc)) }
+    }
+
+    /// Constructs a new `Box` with uninitialized contents, with the memory
+    /// being filled with `0` bytes in the provided allocator.
+    ///
+    /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+    /// of this method.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let zero = Box::<u32, _>::new_zeroed_in(System);
+    /// let zero = unsafe { zero.assume_init() };
+    ///
+    /// assert_eq!(*zero, 0)
+    /// ```
+    ///
+    /// [zeroed]: mem::MaybeUninit::zeroed
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[cfg(not(no_global_oom_handling))]
+    // #[unstable(feature = "new_uninit", issue = "63291")]
+    #[must_use]
+    pub const fn new_zeroed_in(alloc: A) -> Box<mem::MaybeUninit<T>, A>
+    where
+        A: ~const Allocator + ~const Destruct,
+    {
+        let layout = Layout::new::<mem::MaybeUninit<T>>();
+        // NOTE: Prefer match over unwrap_or_else since closure sometimes not inlineable.
+        // That would make code size bigger.
+        match Box::try_new_zeroed_in(alloc) {
+            Ok(m) => m,
+            Err(_) => handle_alloc_error(layout),
+        }
+    }
+
+    /// Constructs a new `Box` with uninitialized contents, with the memory
+    /// being filled with `0` bytes in the provided allocator,
+    /// returning an error if the allocation fails,
+    ///
+    /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+    /// of this method.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let zero = Box::<u32, _>::try_new_zeroed_in(System)?;
+    /// let zero = unsafe { zero.assume_init() };
+    ///
+    /// assert_eq!(*zero, 0);
+    /// # Ok::<(), std::alloc::AllocError>(())
+    /// ```
+    ///
+    /// [zeroed]: mem::MaybeUninit::zeroed
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    // #[unstable(feature = "new_uninit", issue = "63291")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    pub const fn try_new_zeroed_in(alloc: A) -> Result<Box<mem::MaybeUninit<T>, A>, AllocError>
+    where
+        A: ~const Allocator + ~const Destruct,
+    {
+        let layout = Layout::new::<mem::MaybeUninit<T>>();
+        let ptr = alloc.allocate_zeroed(layout)?.cast();
+        unsafe { Ok(Box::from_raw_in(ptr.as_ptr(), alloc)) }
+    }
+
+    /// Constructs a new `Pin<Box<T, A>>`. If `T` does not implement `Unpin`, then
+    /// `x` will be pinned in memory and unable to be moved.
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[must_use]
+    #[inline(always)]
+    pub const fn pin_in(x: T, alloc: A) -> Pin<Self>
+    where
+        A: 'static + ~const Allocator + ~const Destruct,
+    {
+        Self::into_pin(Self::new_in(x, alloc))
+    }
+
+    /// Converts a `Box<T>` into a `Box<[T]>`
+    ///
+    /// This conversion does not allocate on the heap and happens in place.
+    #[unstable(feature = "box_into_boxed_slice", issue = "71582")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    pub const fn into_boxed_slice(boxed: Self) -> Box<[T], A> {
+        let (raw, alloc) = Box::into_raw_with_allocator(boxed);
+        unsafe { Box::from_raw_in(raw as *mut [T; 1], alloc) }
+    }
+
+    /// Consumes the `Box`, returning the wrapped value.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(box_into_inner)]
+    ///
+    /// let c = Box::new(5);
+    ///
+    /// assert_eq!(Box::into_inner(c), 5);
+    /// ```
+    #[unstable(feature = "box_into_inner", issue = "80437")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[inline]
+    pub const fn into_inner(boxed: Self) -> T
+    where
+        Self: ~const Destruct,
+    {
+        *boxed
+    }
+}
+
+impl<T> Box<[T]> {
+    /// Constructs a new boxed slice with uninitialized contents.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let mut values = Box::<[u32]>::new_uninit_slice(3);
+    ///
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     values[0].as_mut_ptr().write(1);
+    ///     values[1].as_mut_ptr().write(2);
+    ///     values[2].as_mut_ptr().write(3);
+    ///
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3])
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[must_use]
+    pub fn new_uninit_slice(len: usize) -> Box<[mem::MaybeUninit<T>]> {
+        unsafe { RawVec::with_capacity(len).into_box(len) }
+    }
+
+    /// Constructs a new boxed slice with uninitialized contents, with the memory
+    /// being filled with `0` bytes.
+    ///
+    /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+    /// of this method.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let values = Box::<[u32]>::new_zeroed_slice(3);
+    /// let values = unsafe { values.assume_init() };
+    ///
+    /// assert_eq!(*values, [0, 0, 0])
+    /// ```
+    ///
+    /// [zeroed]: mem::MaybeUninit::zeroed
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[must_use]
+    pub fn new_zeroed_slice(len: usize) -> Box<[mem::MaybeUninit<T>]> {
+        unsafe { RawVec::with_capacity_zeroed(len).into_box(len) }
+    }
+
+    /// Constructs a new boxed slice with uninitialized contents. Returns an error if
+    /// the allocation fails
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// let mut values = Box::<[u32]>::try_new_uninit_slice(3)?;
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     values[0].as_mut_ptr().write(1);
+    ///     values[1].as_mut_ptr().write(2);
+    ///     values[2].as_mut_ptr().write(3);
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3]);
+    /// # Ok::<(), std::alloc::AllocError>(())
+    /// ```
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[inline]
+    pub fn try_new_uninit_slice(len: usize) -> Result<Box<[mem::MaybeUninit<T>]>, AllocError> {
+        unsafe {
+            let layout = match Layout::array::<mem::MaybeUninit<T>>(len) {
+                Ok(l) => l,
+                Err(_) => return Err(AllocError),
+            };
+            let ptr = Global.allocate(layout)?;
+            Ok(RawVec::from_raw_parts_in(ptr.as_mut_ptr() as *mut _, len, Global).into_box(len))
+        }
+    }
+
+    /// Constructs a new boxed slice with uninitialized contents, with the memory
+    /// being filled with `0` bytes. Returns an error if the allocation fails
+    ///
+    /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+    /// of this method.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// let values = Box::<[u32]>::try_new_zeroed_slice(3)?;
+    /// let values = unsafe { values.assume_init() };
+    ///
+    /// assert_eq!(*values, [0, 0, 0]);
+    /// # Ok::<(), std::alloc::AllocError>(())
+    /// ```
+    ///
+    /// [zeroed]: mem::MaybeUninit::zeroed
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[inline]
+    pub fn try_new_zeroed_slice(len: usize) -> Result<Box<[mem::MaybeUninit<T>]>, AllocError> {
+        unsafe {
+            let layout = match Layout::array::<mem::MaybeUninit<T>>(len) {
+                Ok(l) => l,
+                Err(_) => return Err(AllocError),
+            };
+            let ptr = Global.allocate_zeroed(layout)?;
+            Ok(RawVec::from_raw_parts_in(ptr.as_mut_ptr() as *mut _, len, Global).into_box(len))
+        }
+    }
+}
+
+impl<T, A: Allocator> Box<[T], A> {
+    /// Constructs a new boxed slice with uninitialized contents in the provided allocator.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let mut values = Box::<[u32], _>::new_uninit_slice_in(3, System);
+    ///
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     values[0].as_mut_ptr().write(1);
+    ///     values[1].as_mut_ptr().write(2);
+    ///     values[2].as_mut_ptr().write(3);
+    ///
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3])
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    // #[unstable(feature = "new_uninit", issue = "63291")]
+    #[must_use]
+    pub fn new_uninit_slice_in(len: usize, alloc: A) -> Box<[mem::MaybeUninit<T>], A> {
+        unsafe { RawVec::with_capacity_in(len, alloc).into_box(len) }
+    }
+
+    /// Constructs a new boxed slice with uninitialized contents in the provided allocator,
+    /// with the memory being filled with `0` bytes.
+    ///
+    /// See [`MaybeUninit::zeroed`][zeroed] for examples of correct and incorrect usage
+    /// of this method.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, new_uninit)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let values = Box::<[u32], _>::new_zeroed_slice_in(3, System);
+    /// let values = unsafe { values.assume_init() };
+    ///
+    /// assert_eq!(*values, [0, 0, 0])
+    /// ```
+    ///
+    /// [zeroed]: mem::MaybeUninit::zeroed
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    // #[unstable(feature = "new_uninit", issue = "63291")]
+    #[must_use]
+    pub fn new_zeroed_slice_in(len: usize, alloc: A) -> Box<[mem::MaybeUninit<T>], A> {
+        unsafe { RawVec::with_capacity_zeroed_in(len, alloc).into_box(len) }
+    }
+}
+
+impl<T, A: Allocator> Box<mem::MaybeUninit<T>, A> {
+    /// Converts to `Box<T, A>`.
+    ///
+    /// # Safety
+    ///
+    /// As with [`MaybeUninit::assume_init`],
+    /// it is up to the caller to guarantee that the value
+    /// really is in an initialized state.
+    /// Calling this when the content is not yet fully initialized
+    /// causes immediate undefined behavior.
+    ///
+    /// [`MaybeUninit::assume_init`]: mem::MaybeUninit::assume_init
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let mut five = Box::<u32>::new_uninit();
+    ///
+    /// let five: Box<u32> = unsafe {
+    ///     // Deferred initialization:
+    ///     five.as_mut_ptr().write(5);
+    ///
+    ///     five.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*five, 5)
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[inline]
+    pub const unsafe fn assume_init(self) -> Box<T, A> {
+        let (raw, alloc) = Box::into_raw_with_allocator(self);
+        unsafe { Box::from_raw_in(raw as *mut T, alloc) }
+    }
+
+    /// Writes the value and converts to `Box<T, A>`.
+    ///
+    /// This method converts the box similarly to [`Box::assume_init`] but
+    /// writes `value` into it before conversion thus guaranteeing safety.
+    /// In some scenarios use of this method may improve performance because
+    /// the compiler may be able to optimize copying from stack.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let big_box = Box::<[usize; 1024]>::new_uninit();
+    ///
+    /// let mut array = [0; 1024];
+    /// for (i, place) in array.iter_mut().enumerate() {
+    ///     *place = i;
+    /// }
+    ///
+    /// // The optimizer may be able to elide this copy, so previous code writes
+    /// // to heap directly.
+    /// let big_box = Box::write(big_box, array);
+    ///
+    /// for (i, x) in big_box.iter().enumerate() {
+    ///     assert_eq!(*x, i);
+    /// }
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[inline]
+    pub const fn write(mut boxed: Self, value: T) -> Box<T, A> {
+        unsafe {
+            (*boxed).write(value);
+            boxed.assume_init()
+        }
+    }
+}
+
+impl<T, A: Allocator> Box<[mem::MaybeUninit<T>], A> {
+    /// Converts to `Box<[T], A>`.
+    ///
+    /// # Safety
+    ///
+    /// As with [`MaybeUninit::assume_init`],
+    /// it is up to the caller to guarantee that the values
+    /// really are in an initialized state.
+    /// Calling this when the content is not yet fully initialized
+    /// causes immediate undefined behavior.
+    ///
+    /// [`MaybeUninit::assume_init`]: mem::MaybeUninit::assume_init
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let mut values = Box::<[u32]>::new_uninit_slice(3);
+    ///
+    /// let values = unsafe {
+    ///     // Deferred initialization:
+    ///     values[0].as_mut_ptr().write(1);
+    ///     values[1].as_mut_ptr().write(2);
+    ///     values[2].as_mut_ptr().write(3);
+    ///
+    ///     values.assume_init()
+    /// };
+    ///
+    /// assert_eq!(*values, [1, 2, 3])
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub unsafe fn assume_init(self) -> Box<[T], A> {
+        let (raw, alloc) = Box::into_raw_with_allocator(self);
+        unsafe { Box::from_raw_in(raw as *mut [T], alloc) }
+    }
+}
+
+impl<T: ?Sized> Box<T> {
+    /// Constructs a box from a raw pointer.
+    ///
+    /// After calling this function, the raw pointer is owned by the
+    /// resulting `Box`. Specifically, the `Box` destructor will call
+    /// the destructor of `T` and free the allocated memory. For this
+    /// to be safe, the memory must have been allocated in accordance
+    /// with the [memory layout] used by `Box` .
+    ///
+    /// # Safety
+    ///
+    /// This function is unsafe because improper use may lead to
+    /// memory problems. For example, a double-free may occur if the
+    /// function is called twice on the same raw pointer.
+    ///
+    /// The safety conditions are described in the [memory layout] section.
+    ///
+    /// # Examples
+    ///
+    /// Recreate a `Box` which was previously converted to a raw pointer
+    /// using [`Box::into_raw`]:
+    /// ```
+    /// let x = Box::new(5);
+    /// let ptr = Box::into_raw(x);
+    /// let x = unsafe { Box::from_raw(ptr) };
+    /// ```
+    /// Manually create a `Box` from scratch by using the global allocator:
+    /// ```
+    /// use std::alloc::{alloc, Layout};
+    ///
+    /// unsafe {
+    ///     let ptr = alloc(Layout::new::<i32>()) as *mut i32;
+    ///     // In general .write is required to avoid attempting to destruct
+    ///     // the (uninitialized) previous contents of `ptr`, though for this
+    ///     // simple example `*ptr = 5` would have worked as well.
+    ///     ptr.write(5);
+    ///     let x = Box::from_raw(ptr);
+    /// }
+    /// ```
+    ///
+    /// [memory layout]: self#memory-layout
+    /// [`Layout`]: crate::Layout
+    #[stable(feature = "box_raw", since = "1.4.0")]
+    #[inline]
+    pub unsafe fn from_raw(raw: *mut T) -> Self {
+        unsafe { Self::from_raw_in(raw, Global) }
+    }
+}
+
+impl<T: ?Sized, A: Allocator> Box<T, A> {
+    /// Constructs a box from a raw pointer in the given allocator.
+    ///
+    /// After calling this function, the raw pointer is owned by the
+    /// resulting `Box`. Specifically, the `Box` destructor will call
+    /// the destructor of `T` and free the allocated memory. For this
+    /// to be safe, the memory must have been allocated in accordance
+    /// with the [memory layout] used by `Box` .
+    ///
+    /// # Safety
+    ///
+    /// This function is unsafe because improper use may lead to
+    /// memory problems. For example, a double-free may occur if the
+    /// function is called twice on the same raw pointer.
+    ///
+    ///
+    /// # Examples
+    ///
+    /// Recreate a `Box` which was previously converted to a raw pointer
+    /// using [`Box::into_raw_with_allocator`]:
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let x = Box::new_in(5, System);
+    /// let (ptr, alloc) = Box::into_raw_with_allocator(x);
+    /// let x = unsafe { Box::from_raw_in(ptr, alloc) };
+    /// ```
+    /// Manually create a `Box` from scratch by using the system allocator:
+    /// ```
+    /// #![feature(allocator_api, slice_ptr_get)]
+    ///
+    /// use std::alloc::{Allocator, Layout, System};
+    ///
+    /// unsafe {
+    ///     let ptr = System.allocate(Layout::new::<i32>())?.as_mut_ptr() as *mut i32;
+    ///     // In general .write is required to avoid attempting to destruct
+    ///     // the (uninitialized) previous contents of `ptr`, though for this
+    ///     // simple example `*ptr = 5` would have worked as well.
+    ///     ptr.write(5);
+    ///     let x = Box::from_raw_in(ptr, System);
+    /// }
+    /// # Ok::<(), std::alloc::AllocError>(())
+    /// ```
+    ///
+    /// [memory layout]: self#memory-layout
+    /// [`Layout`]: crate::Layout
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[inline]
+    pub const unsafe fn from_raw_in(raw: *mut T, alloc: A) -> Self {
+        Box(unsafe { Unique::new_unchecked(raw) }, alloc)
+    }
+
+    /// Consumes the `Box`, returning a wrapped raw pointer.
+    ///
+    /// The pointer will be properly aligned and non-null.
+    ///
+    /// After calling this function, the caller is responsible for the
+    /// memory previously managed by the `Box`. In particular, the
+    /// caller should properly destroy `T` and release the memory, taking
+    /// into account the [memory layout] used by `Box`. The easiest way to
+    /// do this is to convert the raw pointer back into a `Box` with the
+    /// [`Box::from_raw`] function, allowing the `Box` destructor to perform
+    /// the cleanup.
+    ///
+    /// Note: this is an associated function, which means that you have
+    /// to call it as `Box::into_raw(b)` instead of `b.into_raw()`. This
+    /// is so that there is no conflict with a method on the inner type.
+    ///
+    /// # Examples
+    /// Converting the raw pointer back into a `Box` with [`Box::from_raw`]
+    /// for automatic cleanup:
+    /// ```
+    /// let x = Box::new(String::from("Hello"));
+    /// let ptr = Box::into_raw(x);
+    /// let x = unsafe { Box::from_raw(ptr) };
+    /// ```
+    /// Manual cleanup by explicitly running the destructor and deallocating
+    /// the memory:
+    /// ```
+    /// use std::alloc::{dealloc, Layout};
+    /// use std::ptr;
+    ///
+    /// let x = Box::new(String::from("Hello"));
+    /// let p = Box::into_raw(x);
+    /// unsafe {
+    ///     ptr::drop_in_place(p);
+    ///     dealloc(p as *mut u8, Layout::new::<String>());
+    /// }
+    /// ```
+    ///
+    /// [memory layout]: self#memory-layout
+    #[stable(feature = "box_raw", since = "1.4.0")]
+    #[inline]
+    pub fn into_raw(b: Self) -> *mut T {
+        Self::into_raw_with_allocator(b).0
+    }
+
+    /// Consumes the `Box`, returning a wrapped raw pointer and the allocator.
+    ///
+    /// The pointer will be properly aligned and non-null.
+    ///
+    /// After calling this function, the caller is responsible for the
+    /// memory previously managed by the `Box`. In particular, the
+    /// caller should properly destroy `T` and release the memory, taking
+    /// into account the [memory layout] used by `Box`. The easiest way to
+    /// do this is to convert the raw pointer back into a `Box` with the
+    /// [`Box::from_raw_in`] function, allowing the `Box` destructor to perform
+    /// the cleanup.
+    ///
+    /// Note: this is an associated function, which means that you have
+    /// to call it as `Box::into_raw_with_allocator(b)` instead of `b.into_raw_with_allocator()`. This
+    /// is so that there is no conflict with a method on the inner type.
+    ///
+    /// # Examples
+    /// Converting the raw pointer back into a `Box` with [`Box::from_raw_in`]
+    /// for automatic cleanup:
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let x = Box::new_in(String::from("Hello"), System);
+    /// let (ptr, alloc) = Box::into_raw_with_allocator(x);
+    /// let x = unsafe { Box::from_raw_in(ptr, alloc) };
+    /// ```
+    /// Manual cleanup by explicitly running the destructor and deallocating
+    /// the memory:
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::{Allocator, Layout, System};
+    /// use std::ptr::{self, NonNull};
+    ///
+    /// let x = Box::new_in(String::from("Hello"), System);
+    /// let (ptr, alloc) = Box::into_raw_with_allocator(x);
+    /// unsafe {
+    ///     ptr::drop_in_place(ptr);
+    ///     let non_null = NonNull::new_unchecked(ptr);
+    ///     alloc.deallocate(non_null.cast(), Layout::new::<String>());
+    /// }
+    /// ```
+    ///
+    /// [memory layout]: self#memory-layout
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[inline]
+    pub const fn into_raw_with_allocator(b: Self) -> (*mut T, A) {
+        let (leaked, alloc) = Box::into_unique(b);
+        (leaked.as_ptr(), alloc)
+    }
+
+    #[unstable(
+        feature = "ptr_internals",
+        issue = "none",
+        reason = "use `Box::leak(b).into()` or `Unique::from(Box::leak(b))` instead"
+    )]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[inline]
+    #[doc(hidden)]
+    pub const fn into_unique(b: Self) -> (Unique<T>, A) {
+        // Box is recognized as a "unique pointer" by Stacked Borrows, but internally it is a
+        // raw pointer for the type system. Turning it directly into a raw pointer would not be
+        // recognized as "releasing" the unique pointer to permit aliased raw accesses,
+        // so all raw pointer methods have to go through `Box::leak`. Turning *that* to a raw pointer
+        // behaves correctly.
+        let alloc = unsafe { ptr::read(&b.1) };
+        (Unique::from(Box::leak(b)), alloc)
+    }
+
+    /// Returns a reference to the underlying allocator.
+    ///
+    /// Note: this is an associated function, which means that you have
+    /// to call it as `Box::allocator(&b)` instead of `b.allocator()`. This
+    /// is so that there is no conflict with a method on the inner type.
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[inline]
+    pub const fn allocator(b: &Self) -> &A {
+        &b.1
+    }
+
+    /// Consumes and leaks the `Box`, returning a mutable reference,
+    /// `&'a mut T`. Note that the type `T` must outlive the chosen lifetime
+    /// `'a`. If the type has only static references, or none at all, then this
+    /// may be chosen to be `'static`.
+    ///
+    /// This function is mainly useful for data that lives for the remainder of
+    /// the program's life. Dropping the returned reference will cause a memory
+    /// leak. If this is not acceptable, the reference should first be wrapped
+    /// with the [`Box::from_raw`] function producing a `Box`. This `Box` can
+    /// then be dropped which will properly destroy `T` and release the
+    /// allocated memory.
+    ///
+    /// Note: this is an associated function, which means that you have
+    /// to call it as `Box::leak(b)` instead of `b.leak()`. This
+    /// is so that there is no conflict with a method on the inner type.
+    ///
+    /// # Examples
+    ///
+    /// Simple usage:
+    ///
+    /// ```
+    /// let x = Box::new(41);
+    /// let static_ref: &'static mut usize = Box::leak(x);
+    /// *static_ref += 1;
+    /// assert_eq!(*static_ref, 42);
+    /// ```
+    ///
+    /// Unsized data:
+    ///
+    /// ```
+    /// let x = vec![1, 2, 3].into_boxed_slice();
+    /// let static_ref = Box::leak(x);
+    /// static_ref[0] = 4;
+    /// assert_eq!(*static_ref, [4, 2, 3]);
+    /// ```
+    #[stable(feature = "box_leak", since = "1.26.0")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    #[inline]
+    pub const fn leak<'a>(b: Self) -> &'a mut T
+    where
+        A: 'a,
+    {
+        unsafe { &mut *mem::ManuallyDrop::new(b).0.as_ptr() }
+    }
+
+    /// Converts a `Box<T>` into a `Pin<Box<T>>`
+    ///
+    /// This conversion does not allocate on the heap and happens in place.
+    ///
+    /// This is also available via [`From`].
+    #[unstable(feature = "box_into_pin", issue = "62370")]
+    #[rustc_const_unstable(feature = "const_box", issue = "92521")]
+    pub const fn into_pin(boxed: Self) -> Pin<Self>
+    where
+        A: 'static,
+    {
+        // It's not possible to move or replace the insides of a `Pin<Box<T>>`
+        // when `T: !Unpin`,  so it's safe to pin it directly without any
+        // additional requirements.
+        unsafe { Pin::new_unchecked(boxed) }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<#[may_dangle] T: ?Sized, A: Allocator> Drop for Box<T, A> {
+    fn drop(&mut self) {
+        // FIXME: Do nothing, drop is currently performed by compiler.
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Default> Default for Box<T> {
+    /// Creates a `Box<T>`, with the `Default` value for T.
+    fn default() -> Self {
+        box T::default()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+impl<T> const Default for Box<[T]> {
+    fn default() -> Self {
+        let ptr: Unique<[T]> = Unique::<[T; 0]>::dangling();
+        Box(ptr, Global)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "default_box_extra", since = "1.17.0")]
+#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+impl const Default for Box<str> {
+    fn default() -> Self {
+        // SAFETY: This is the same as `Unique::cast<U>` but with an unsized `U = str`.
+        let ptr: Unique<str> = unsafe {
+            let bytes: Unique<[u8]> = Unique::<[u8; 0]>::dangling();
+            Unique::new_unchecked(bytes.as_ptr() as *mut str)
+        };
+        Box(ptr, Global)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone, A: Allocator + Clone> Clone for Box<T, A> {
+    /// Returns a new box with a `clone()` of this box's contents.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let x = Box::new(5);
+    /// let y = x.clone();
+    ///
+    /// // The value is the same
+    /// assert_eq!(x, y);
+    ///
+    /// // But they are unique objects
+    /// assert_ne!(&*x as *const i32, &*y as *const i32);
+    /// ```
+    #[inline]
+    fn clone(&self) -> Self {
+        // Pre-allocate memory to allow writing the cloned value directly.
+        let mut boxed = Self::new_uninit_in(self.1.clone());
+        unsafe {
+            (**self).write_clone_into_raw(boxed.as_mut_ptr());
+            boxed.assume_init()
+        }
+    }
+
+    /// Copies `source`'s contents into `self` without creating a new allocation.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let x = Box::new(5);
+    /// let mut y = Box::new(10);
+    /// let yp: *const i32 = &*y;
+    ///
+    /// y.clone_from(&x);
+    ///
+    /// // The value is the same
+    /// assert_eq!(x, y);
+    ///
+    /// // And no allocation occurred
+    /// assert_eq!(yp, &*y);
+    /// ```
+    #[inline]
+    fn clone_from(&mut self, source: &Self) {
+        (**self).clone_from(&(**source));
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_slice_clone", since = "1.3.0")]
+impl Clone for Box<str> {
+    fn clone(&self) -> Self {
+        // this makes a copy of the data
+        let buf: Box<[u8]> = self.as_bytes().into();
+        unsafe { from_boxed_utf8_unchecked(buf) }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + PartialEq, A: Allocator> PartialEq for Box<T, A> {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        PartialEq::eq(&**self, &**other)
+    }
+    #[inline]
+    fn ne(&self, other: &Self) -> bool {
+        PartialEq::ne(&**self, &**other)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + PartialOrd, A: Allocator> PartialOrd for Box<T, A> {
+    #[inline]
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        PartialOrd::partial_cmp(&**self, &**other)
+    }
+    #[inline]
+    fn lt(&self, other: &Self) -> bool {
+        PartialOrd::lt(&**self, &**other)
+    }
+    #[inline]
+    fn le(&self, other: &Self) -> bool {
+        PartialOrd::le(&**self, &**other)
+    }
+    #[inline]
+    fn ge(&self, other: &Self) -> bool {
+        PartialOrd::ge(&**self, &**other)
+    }
+    #[inline]
+    fn gt(&self, other: &Self) -> bool {
+        PartialOrd::gt(&**self, &**other)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + Ord, A: Allocator> Ord for Box<T, A> {
+    #[inline]
+    fn cmp(&self, other: &Self) -> Ordering {
+        Ord::cmp(&**self, &**other)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + Eq, A: Allocator> Eq for Box<T, A> {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized + Hash, A: Allocator> Hash for Box<T, A> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        (**self).hash(state);
+    }
+}
+
+#[stable(feature = "indirect_hasher_impl", since = "1.22.0")]
+impl<T: ?Sized + Hasher, A: Allocator> Hasher for Box<T, A> {
+    fn finish(&self) -> u64 {
+        (**self).finish()
+    }
+    fn write(&mut self, bytes: &[u8]) {
+        (**self).write(bytes)
+    }
+    fn write_u8(&mut self, i: u8) {
+        (**self).write_u8(i)
+    }
+    fn write_u16(&mut self, i: u16) {
+        (**self).write_u16(i)
+    }
+    fn write_u32(&mut self, i: u32) {
+        (**self).write_u32(i)
+    }
+    fn write_u64(&mut self, i: u64) {
+        (**self).write_u64(i)
+    }
+    fn write_u128(&mut self, i: u128) {
+        (**self).write_u128(i)
+    }
+    fn write_usize(&mut self, i: usize) {
+        (**self).write_usize(i)
+    }
+    fn write_i8(&mut self, i: i8) {
+        (**self).write_i8(i)
+    }
+    fn write_i16(&mut self, i: i16) {
+        (**self).write_i16(i)
+    }
+    fn write_i32(&mut self, i: i32) {
+        (**self).write_i32(i)
+    }
+    fn write_i64(&mut self, i: i64) {
+        (**self).write_i64(i)
+    }
+    fn write_i128(&mut self, i: i128) {
+        (**self).write_i128(i)
+    }
+    fn write_isize(&mut self, i: isize) {
+        (**self).write_isize(i)
+    }
+    fn write_length_prefix(&mut self, len: usize) {
+        (**self).write_length_prefix(len)
+    }
+    fn write_str(&mut self, s: &str) {
+        (**self).write_str(s)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "from_for_ptrs", since = "1.6.0")]
+impl<T> From<T> for Box<T> {
+    /// Converts a `T` into a `Box<T>`
+    ///
+    /// The conversion allocates on the heap and moves `t`
+    /// from the stack into it.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// let x = 5;
+    /// let boxed = Box::new(5);
+    ///
+    /// assert_eq!(Box::from(x), boxed);
+    /// ```
+    fn from(t: T) -> Self {
+        Box::new(t)
+    }
+}
+
+#[stable(feature = "pin", since = "1.33.0")]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+impl<T: ?Sized, A: Allocator> const From<Box<T, A>> for Pin<Box<T, A>>
+where
+    A: 'static,
+{
+    /// Converts a `Box<T>` into a `Pin<Box<T>>`
+    ///
+    /// This conversion does not allocate on the heap and happens in place.
+    fn from(boxed: Box<T, A>) -> Self {
+        Box::into_pin(boxed)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_slice", since = "1.17.0")]
+impl<T: Copy> From<&[T]> for Box<[T]> {
+    /// Converts a `&[T]` into a `Box<[T]>`
+    ///
+    /// This conversion allocates on the heap
+    /// and performs a copy of `slice`.
+    ///
+    /// # Examples
+    /// ```rust
+    /// // create a &[u8] which will be used to create a Box<[u8]>
+    /// let slice: &[u8] = &[104, 101, 108, 108, 111];
+    /// let boxed_slice: Box<[u8]> = Box::from(slice);
+    ///
+    /// println!("{boxed_slice:?}");
+    /// ```
+    fn from(slice: &[T]) -> Box<[T]> {
+        let len = slice.len();
+        let buf = RawVec::with_capacity(len);
+        unsafe {
+            ptr::copy_nonoverlapping(slice.as_ptr(), buf.ptr(), len);
+            buf.into_box(slice.len()).assume_init()
+        }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_cow", since = "1.45.0")]
+impl<T: Copy> From<Cow<'_, [T]>> for Box<[T]> {
+    /// Converts a `Cow<'_, [T]>` into a `Box<[T]>`
+    ///
+    /// When `cow` is the `Cow::Borrowed` variant, this
+    /// conversion allocates on the heap and copies the
+    /// underlying slice. Otherwise, it will try to reuse the owned
+    /// `Vec`'s allocation.
+    #[inline]
+    fn from(cow: Cow<'_, [T]>) -> Box<[T]> {
+        match cow {
+            Cow::Borrowed(slice) => Box::from(slice),
+            Cow::Owned(slice) => Box::from(slice),
+        }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_slice", since = "1.17.0")]
+impl From<&str> for Box<str> {
+    /// Converts a `&str` into a `Box<str>`
+    ///
+    /// This conversion allocates on the heap
+    /// and performs a copy of `s`.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// let boxed: Box<str> = Box::from("hello");
+    /// println!("{boxed}");
+    /// ```
+    #[inline]
+    fn from(s: &str) -> Box<str> {
+        unsafe { from_boxed_utf8_unchecked(Box::from(s.as_bytes())) }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_cow", since = "1.45.0")]
+impl From<Cow<'_, str>> for Box<str> {
+    /// Converts a `Cow<'_, str>` into a `Box<str>`
+    ///
+    /// When `cow` is the `Cow::Borrowed` variant, this
+    /// conversion allocates on the heap and copies the
+    /// underlying `str`. Otherwise, it will try to reuse the owned
+    /// `String`'s allocation.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// use std::borrow::Cow;
+    ///
+    /// let unboxed = Cow::Borrowed("hello");
+    /// let boxed: Box<str> = Box::from(unboxed);
+    /// println!("{boxed}");
+    /// ```
+    ///
+    /// ```rust
+    /// # use std::borrow::Cow;
+    /// let unboxed = Cow::Owned("hello".to_string());
+    /// let boxed: Box<str> = Box::from(unboxed);
+    /// println!("{boxed}");
+    /// ```
+    #[inline]
+    fn from(cow: Cow<'_, str>) -> Box<str> {
+        match cow {
+            Cow::Borrowed(s) => Box::from(s),
+            Cow::Owned(s) => Box::from(s),
+        }
+    }
+}
+
+#[stable(feature = "boxed_str_conv", since = "1.19.0")]
+impl<A: Allocator> From<Box<str, A>> for Box<[u8], A> {
+    /// Converts a `Box<str>` into a `Box<[u8]>`
+    ///
+    /// This conversion does not allocate on the heap and happens in place.
+    ///
+    /// # Examples
+    /// ```rust
+    /// // create a Box<str> which will be used to create a Box<[u8]>
+    /// let boxed: Box<str> = Box::from("hello");
+    /// let boxed_str: Box<[u8]> = Box::from(boxed);
+    ///
+    /// // create a &[u8] which will be used to create a Box<[u8]>
+    /// let slice: &[u8] = &[104, 101, 108, 108, 111];
+    /// let boxed_slice = Box::from(slice);
+    ///
+    /// assert_eq!(boxed_slice, boxed_str);
+    /// ```
+    #[inline]
+    fn from(s: Box<str, A>) -> Self {
+        let (raw, alloc) = Box::into_raw_with_allocator(s);
+        unsafe { Box::from_raw_in(raw as *mut [u8], alloc) }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_array", since = "1.45.0")]
+impl<T, const N: usize> From<[T; N]> for Box<[T]> {
+    /// Converts a `[T; N]` into a `Box<[T]>`
+    ///
+    /// This conversion moves the array to newly heap-allocated memory.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// let boxed: Box<[u8]> = Box::from([4, 2]);
+    /// println!("{boxed:?}");
+    /// ```
+    fn from(array: [T; N]) -> Box<[T]> {
+        box array
+    }
+}
+
+#[stable(feature = "boxed_slice_try_from", since = "1.43.0")]
+impl<T, const N: usize> TryFrom<Box<[T]>> for Box<[T; N]> {
+    type Error = Box<[T]>;
+
+    /// Attempts to convert a `Box<[T]>` into a `Box<[T; N]>`.
+    ///
+    /// The conversion occurs in-place and does not require a
+    /// new memory allocation.
+    ///
+    /// # Errors
+    ///
+    /// Returns the old `Box<[T]>` in the `Err` variant if
+    /// `boxed_slice.len()` does not equal `N`.
+    fn try_from(boxed_slice: Box<[T]>) -> Result<Self, Self::Error> {
+        if boxed_slice.len() == N {
+            Ok(unsafe { Box::from_raw(Box::into_raw(boxed_slice) as *mut [T; N]) })
+        } else {
+            Err(boxed_slice)
+        }
+    }
+}
+
+impl<A: Allocator> Box<dyn Any, A> {
+    /// Attempt to downcast the box to a concrete type.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn print_if_string(value: Box<dyn Any>) {
+    ///     if let Ok(string) = value.downcast::<String>() {
+    ///         println!("String ({}): {}", string.len(), string);
+    ///     }
+    /// }
+    ///
+    /// let my_string = "Hello World".to_string();
+    /// print_if_string(Box::new(my_string));
+    /// print_if_string(Box::new(0i8));
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
+        if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
+    }
+
+    /// Downcasts the box to a concrete type.
+    ///
+    /// For a safe alternative see [`downcast`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(downcast_unchecked)]
+    ///
+    /// use std::any::Any;
+    ///
+    /// let x: Box<dyn Any> = Box::new(1_usize);
+    ///
+    /// unsafe {
+    ///     assert_eq!(*x.downcast_unchecked::<usize>(), 1);
+    /// }
+    /// ```
+    ///
+    /// # Safety
+    ///
+    /// The contained value must be of type `T`. Calling this method
+    /// with the incorrect type is *undefined behavior*.
+    ///
+    /// [`downcast`]: Self::downcast
+    #[inline]
+    #[unstable(feature = "downcast_unchecked", issue = "90850")]
+    pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
+        debug_assert!(self.is::<T>());
+        unsafe {
+            let (raw, alloc): (*mut dyn Any, _) = Box::into_raw_with_allocator(self);
+            Box::from_raw_in(raw as *mut T, alloc)
+        }
+    }
+}
+
+impl<A: Allocator> Box<dyn Any + Send, A> {
+    /// Attempt to downcast the box to a concrete type.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn print_if_string(value: Box<dyn Any + Send>) {
+    ///     if let Ok(string) = value.downcast::<String>() {
+    ///         println!("String ({}): {}", string.len(), string);
+    ///     }
+    /// }
+    ///
+    /// let my_string = "Hello World".to_string();
+    /// print_if_string(Box::new(my_string));
+    /// print_if_string(Box::new(0i8));
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
+        if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
+    }
+
+    /// Downcasts the box to a concrete type.
+    ///
+    /// For a safe alternative see [`downcast`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(downcast_unchecked)]
+    ///
+    /// use std::any::Any;
+    ///
+    /// let x: Box<dyn Any + Send> = Box::new(1_usize);
+    ///
+    /// unsafe {
+    ///     assert_eq!(*x.downcast_unchecked::<usize>(), 1);
+    /// }
+    /// ```
+    ///
+    /// # Safety
+    ///
+    /// The contained value must be of type `T`. Calling this method
+    /// with the incorrect type is *undefined behavior*.
+    ///
+    /// [`downcast`]: Self::downcast
+    #[inline]
+    #[unstable(feature = "downcast_unchecked", issue = "90850")]
+    pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
+        debug_assert!(self.is::<T>());
+        unsafe {
+            let (raw, alloc): (*mut (dyn Any + Send), _) = Box::into_raw_with_allocator(self);
+            Box::from_raw_in(raw as *mut T, alloc)
+        }
+    }
+}
+
+impl<A: Allocator> Box<dyn Any + Send + Sync, A> {
+    /// Attempt to downcast the box to a concrete type.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::any::Any;
+    ///
+    /// fn print_if_string(value: Box<dyn Any + Send + Sync>) {
+    ///     if let Ok(string) = value.downcast::<String>() {
+    ///         println!("String ({}): {}", string.len(), string);
+    ///     }
+    /// }
+    ///
+    /// let my_string = "Hello World".to_string();
+    /// print_if_string(Box::new(my_string));
+    /// print_if_string(Box::new(0i8));
+    /// ```
+    #[inline]
+    #[stable(feature = "box_send_sync_any_downcast", since = "1.51.0")]
+    pub fn downcast<T: Any>(self) -> Result<Box<T, A>, Self> {
+        if self.is::<T>() { unsafe { Ok(self.downcast_unchecked::<T>()) } } else { Err(self) }
+    }
+
+    /// Downcasts the box to a concrete type.
+    ///
+    /// For a safe alternative see [`downcast`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(downcast_unchecked)]
+    ///
+    /// use std::any::Any;
+    ///
+    /// let x: Box<dyn Any + Send + Sync> = Box::new(1_usize);
+    ///
+    /// unsafe {
+    ///     assert_eq!(*x.downcast_unchecked::<usize>(), 1);
+    /// }
+    /// ```
+    ///
+    /// # Safety
+    ///
+    /// The contained value must be of type `T`. Calling this method
+    /// with the incorrect type is *undefined behavior*.
+    ///
+    /// [`downcast`]: Self::downcast
+    #[inline]
+    #[unstable(feature = "downcast_unchecked", issue = "90850")]
+    pub unsafe fn downcast_unchecked<T: Any>(self) -> Box<T, A> {
+        debug_assert!(self.is::<T>());
+        unsafe {
+            let (raw, alloc): (*mut (dyn Any + Send + Sync), _) =
+                Box::into_raw_with_allocator(self);
+            Box::from_raw_in(raw as *mut T, alloc)
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: fmt::Display + ?Sized, A: Allocator> fmt::Display for Box<T, A> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(&**self, f)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: fmt::Debug + ?Sized, A: Allocator> fmt::Debug for Box<T, A> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(&**self, f)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: ?Sized, A: Allocator> fmt::Pointer for Box<T, A> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        // It's not possible to extract the inner Uniq directly from the Box,
+        // instead we cast it to a *const which aliases the Unique
+        let ptr: *const T = &**self;
+        fmt::Pointer::fmt(&ptr, f)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+impl<T: ?Sized, A: Allocator> const Deref for Box<T, A> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        &**self
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+impl<T: ?Sized, A: Allocator> const DerefMut for Box<T, A> {
+    fn deref_mut(&mut self) -> &mut T {
+        &mut **self
+    }
+}
+
+#[unstable(feature = "receiver_trait", issue = "none")]
+impl<T: ?Sized, A: Allocator> Receiver for Box<T, A> {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator + ?Sized, A: Allocator> Iterator for Box<I, A> {
+    type Item = I::Item;
+    fn next(&mut self) -> Option<I::Item> {
+        (**self).next()
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (**self).size_hint()
+    }
+    fn nth(&mut self, n: usize) -> Option<I::Item> {
+        (**self).nth(n)
+    }
+    fn last(self) -> Option<I::Item> {
+        BoxIter::last(self)
+    }
+}
+
+trait BoxIter {
+    type Item;
+    fn last(self) -> Option<Self::Item>;
+}
+
+impl<I: Iterator + ?Sized, A: Allocator> BoxIter for Box<I, A> {
+    type Item = I::Item;
+    default fn last(self) -> Option<I::Item> {
+        #[inline]
+        fn some<T>(_: Option<T>, x: T) -> Option<T> {
+            Some(x)
+        }
+
+        self.fold(None, some)
+    }
+}
+
+/// Specialization for sized `I`s that uses `I`s implementation of `last()`
+/// instead of the default.
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: Iterator, A: Allocator> BoxIter for Box<I, A> {
+    fn last(self) -> Option<I::Item> {
+        (*self).last()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: DoubleEndedIterator + ?Sized, A: Allocator> DoubleEndedIterator for Box<I, A> {
+    fn next_back(&mut self) -> Option<I::Item> {
+        (**self).next_back()
+    }
+    fn nth_back(&mut self, n: usize) -> Option<I::Item> {
+        (**self).nth_back(n)
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<I: ExactSizeIterator + ?Sized, A: Allocator> ExactSizeIterator for Box<I, A> {
+    fn len(&self) -> usize {
+        (**self).len()
+    }
+    fn is_empty(&self) -> bool {
+        (**self).is_empty()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<I: FusedIterator + ?Sized, A: Allocator> FusedIterator for Box<I, A> {}
+
+#[stable(feature = "boxed_closure_impls", since = "1.35.0")]
+impl<Args, F: FnOnce<Args> + ?Sized, A: Allocator> FnOnce<Args> for Box<F, A> {
+    type Output = <F as FnOnce<Args>>::Output;
+
+    extern "rust-call" fn call_once(self, args: Args) -> Self::Output {
+        <F as FnOnce<Args>>::call_once(*self, args)
+    }
+}
+
+#[stable(feature = "boxed_closure_impls", since = "1.35.0")]
+impl<Args, F: FnMut<Args> + ?Sized, A: Allocator> FnMut<Args> for Box<F, A> {
+    extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output {
+        <F as FnMut<Args>>::call_mut(self, args)
+    }
+}
+
+#[stable(feature = "boxed_closure_impls", since = "1.35.0")]
+impl<Args, F: Fn<Args> + ?Sized, A: Allocator> Fn<Args> for Box<F, A> {
+    extern "rust-call" fn call(&self, args: Args) -> Self::Output {
+        <F as Fn<Args>>::call(self, args)
+    }
+}
+
+#[unstable(feature = "coerce_unsized", issue = "27732")]
+impl<T: ?Sized + Unsize<U>, U: ?Sized, A: Allocator> CoerceUnsized<Box<U, A>> for Box<T, A> {}
+
+#[unstable(feature = "dispatch_from_dyn", issue = "none")]
+impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Box<U>> for Box<T, Global> {}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "boxed_slice_from_iter", since = "1.32.0")]
+impl<I> FromIterator<I> for Box<[I]> {
+    fn from_iter<T: IntoIterator<Item = I>>(iter: T) -> Self {
+        iter.into_iter().collect::<Vec<_>>().into_boxed_slice()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_slice_clone", since = "1.3.0")]
+impl<T: Clone, A: Allocator + Clone> Clone for Box<[T], A> {
+    fn clone(&self) -> Self {
+        let alloc = Box::allocator(self).clone();
+        self.to_vec_in(alloc).into_boxed_slice()
+    }
+
+    fn clone_from(&mut self, other: &Self) {
+        if self.len() == other.len() {
+            self.clone_from_slice(&other);
+        } else {
+            *self = other.clone();
+        }
+    }
+}
+
+#[stable(feature = "box_borrow", since = "1.1.0")]
+impl<T: ?Sized, A: Allocator> borrow::Borrow<T> for Box<T, A> {
+    fn borrow(&self) -> &T {
+        &**self
+    }
+}
+
+#[stable(feature = "box_borrow", since = "1.1.0")]
+impl<T: ?Sized, A: Allocator> borrow::BorrowMut<T> for Box<T, A> {
+    fn borrow_mut(&mut self) -> &mut T {
+        &mut **self
+    }
+}
+
+#[stable(since = "1.5.0", feature = "smart_ptr_as_ref")]
+impl<T: ?Sized, A: Allocator> AsRef<T> for Box<T, A> {
+    fn as_ref(&self) -> &T {
+        &**self
+    }
+}
+
+#[stable(since = "1.5.0", feature = "smart_ptr_as_ref")]
+impl<T: ?Sized, A: Allocator> AsMut<T> for Box<T, A> {
+    fn as_mut(&mut self) -> &mut T {
+        &mut **self
+    }
+}
+
+/* Nota bene
+ *
+ *  We could have chosen not to add this impl, and instead have written a
+ *  function of Pin<Box<T>> to Pin<T>. Such a function would not be sound,
+ *  because Box<T> implements Unpin even when T does not, as a result of
+ *  this impl.
+ *
+ *  We chose this API instead of the alternative for a few reasons:
+ *      - Logically, it is helpful to understand pinning in regard to the
+ *        memory region being pointed to. For this reason none of the
+ *        standard library pointer types support projecting through a pin
+ *        (Box<T> is the only pointer type in std for which this would be
+ *        safe.)
+ *      - It is in practice very useful to have Box<T> be unconditionally
+ *        Unpin because of trait objects, for which the structural auto
+ *        trait functionality does not apply (e.g., Box<dyn Foo> would
+ *        otherwise not be Unpin).
+ *
+ *  Another type with the same semantics as Box but only a conditional
+ *  implementation of `Unpin` (where `T: Unpin`) would be valid/safe, and
+ *  could have a method to project a Pin<T> from it.
+ */
+#[stable(feature = "pin", since = "1.33.0")]
+#[rustc_const_unstable(feature = "const_box", issue = "92521")]
+impl<T: ?Sized, A: Allocator> const Unpin for Box<T, A> where A: 'static {}
+
+#[unstable(feature = "generator_trait", issue = "43122")]
+impl<G: ?Sized + Generator<R> + Unpin, R, A: Allocator> Generator<R> for Box<G, A>
+where
+    A: 'static,
+{
+    type Yield = G::Yield;
+    type Return = G::Return;
+
+    fn resume(mut self: Pin<&mut Self>, arg: R) -> GeneratorState<Self::Yield, Self::Return> {
+        G::resume(Pin::new(&mut *self), arg)
+    }
+}
+
+#[unstable(feature = "generator_trait", issue = "43122")]
+impl<G: ?Sized + Generator<R>, R, A: Allocator> Generator<R> for Pin<Box<G, A>>
+where
+    A: 'static,
+{
+    type Yield = G::Yield;
+    type Return = G::Return;
+
+    fn resume(mut self: Pin<&mut Self>, arg: R) -> GeneratorState<Self::Yield, Self::Return> {
+        G::resume((*self).as_mut(), arg)
+    }
+}
+
+#[stable(feature = "futures_api", since = "1.36.0")]
+impl<F: ?Sized + Future + Unpin, A: Allocator> Future for Box<F, A>
+where
+    A: 'static,
+{
+    type Output = F::Output;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        F::poll(Pin::new(&mut *self), cx)
+    }
+}
+
+#[unstable(feature = "async_iterator", issue = "79024")]
+impl<S: ?Sized + AsyncIterator + Unpin> AsyncIterator for Box<S> {
+    type Item = S::Item;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        Pin::new(&mut **self).poll_next(cx)
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (**self).size_hint()
+    }
+}
diff --git a/rust/alloc/boxed/thin.rs b/rust/alloc/boxed/thin.rs
new file mode 100644
index 000000000000..9135203114fc
--- /dev/null
+++ b/rust/alloc/boxed/thin.rs
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// Based on
+// https://github.com/matthieu-m/rfc2580/blob/b58d1d3cba0d4b5e859d3617ea2d0943aaa31329/examples/thin.rs
+// by matthieu-m
+use crate::alloc::{self, Layout, LayoutError};
+use core::fmt::{self, Debug, Display, Formatter};
+use core::marker::PhantomData;
+#[cfg(not(no_global_oom_handling))]
+use core::marker::Unsize;
+use core::mem;
+use core::ops::{Deref, DerefMut};
+use core::ptr::Pointee;
+use core::ptr::{self, NonNull};
+
+/// ThinBox.
+///
+/// A thin pointer for heap allocation, regardless of T.
+///
+/// # Examples
+///
+/// ```
+/// #![feature(thin_box)]
+/// use std::boxed::ThinBox;
+///
+/// let five = ThinBox::new(5);
+/// let thin_slice = ThinBox::<[i32]>::new_unsize([1, 2, 3, 4]);
+///
+/// use std::mem::{size_of, size_of_val};
+/// let size_of_ptr = size_of::<*const ()>();
+/// assert_eq!(size_of_ptr, size_of_val(&five));
+/// assert_eq!(size_of_ptr, size_of_val(&thin_slice));
+/// ```
+#[unstable(feature = "thin_box", issue = "92791")]
+pub struct ThinBox<T: ?Sized> {
+    ptr: WithHeader<<T as Pointee>::Metadata>,
+    _marker: PhantomData<T>,
+}
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T> ThinBox<T> {
+    /// Moves a type to the heap with its `Metadata` stored in the heap allocation instead of on
+    /// the stack.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(thin_box)]
+    /// use std::boxed::ThinBox;
+    ///
+    /// let five = ThinBox::new(5);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    pub fn new(value: T) -> Self {
+        let meta = ptr::metadata(&value);
+        let ptr = WithHeader::new(meta, value);
+        ThinBox { ptr, _marker: PhantomData }
+    }
+}
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<Dyn: ?Sized> ThinBox<Dyn> {
+    /// Moves a type to the heap with its `Metadata` stored in the heap allocation instead of on
+    /// the stack.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(thin_box)]
+    /// use std::boxed::ThinBox;
+    ///
+    /// let thin_slice = ThinBox::<[i32]>::new_unsize([1, 2, 3, 4]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    pub fn new_unsize<T>(value: T) -> Self
+    where
+        T: Unsize<Dyn>,
+    {
+        let meta = ptr::metadata(&value as &Dyn);
+        let ptr = WithHeader::new(meta, value);
+        ThinBox { ptr, _marker: PhantomData }
+    }
+}
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T: ?Sized + Debug> Debug for ThinBox<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        Debug::fmt(self.deref(), f)
+    }
+}
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T: ?Sized + Display> Display for ThinBox<T> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        Display::fmt(self.deref(), f)
+    }
+}
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T: ?Sized> Deref for ThinBox<T> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        let value = self.data();
+        let metadata = self.meta();
+        let pointer = ptr::from_raw_parts(value as *const (), metadata);
+        unsafe { &*pointer }
+    }
+}
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T: ?Sized> DerefMut for ThinBox<T> {
+    fn deref_mut(&mut self) -> &mut T {
+        let value = self.data();
+        let metadata = self.meta();
+        let pointer = ptr::from_raw_parts_mut::<T>(value as *mut (), metadata);
+        unsafe { &mut *pointer }
+    }
+}
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T: ?Sized> Drop for ThinBox<T> {
+    fn drop(&mut self) {
+        unsafe {
+            let value = self.deref_mut();
+            let value = value as *mut T;
+            self.ptr.drop::<T>(value);
+        }
+    }
+}
+
+#[unstable(feature = "thin_box", issue = "92791")]
+impl<T: ?Sized> ThinBox<T> {
+    fn meta(&self) -> <T as Pointee>::Metadata {
+        //  Safety:
+        //  -   NonNull and valid.
+        unsafe { *self.ptr.header() }
+    }
+
+    fn data(&self) -> *mut u8 {
+        self.ptr.value()
+    }
+}
+
+/// A pointer to type-erased data, guaranteed to have a header `H` before the pointed-to location.
+struct WithHeader<H>(NonNull<u8>, PhantomData<H>);
+
+impl<H> WithHeader<H> {
+    #[cfg(not(no_global_oom_handling))]
+    fn new<T>(header: H, value: T) -> WithHeader<H> {
+        let value_layout = Layout::new::<T>();
+        let Ok((layout, value_offset)) = Self::alloc_layout(value_layout) else {
+            // We pass an empty layout here because we do not know which layout caused the
+            // arithmetic overflow in `Layout::extend` and `handle_alloc_error` takes `Layout` as
+            // its argument rather than `Result<Layout, LayoutError>`, also this function has been
+            // stable since 1.28 ._.
+            //
+            // On the other hand, look at this gorgeous turbofish!
+            alloc::handle_alloc_error(Layout::new::<()>());
+        };
+
+        unsafe {
+            let ptr = alloc::alloc(layout);
+
+            if ptr.is_null() {
+                alloc::handle_alloc_error(layout);
+            }
+            //  Safety:
+            //  -   The size is at least `aligned_header_size`.
+            let ptr = ptr.add(value_offset) as *mut _;
+
+            let ptr = NonNull::new_unchecked(ptr);
+
+            let result = WithHeader(ptr, PhantomData);
+            ptr::write(result.header(), header);
+            ptr::write(result.value().cast(), value);
+
+            result
+        }
+    }
+
+    //  Safety:
+    //  -   Assumes that `value` can be dereferenced.
+    unsafe fn drop<T: ?Sized>(&self, value: *mut T) {
+        unsafe {
+            // SAFETY: Layout must have been computable if we're in drop
+            let (layout, value_offset) =
+                Self::alloc_layout(Layout::for_value_raw(value)).unwrap_unchecked();
+
+            ptr::drop_in_place::<T>(value);
+            // We only drop the value because the Pointee trait requires that the metadata is copy
+            // aka trivially droppable
+            alloc::dealloc(self.0.as_ptr().sub(value_offset), layout);
+        }
+    }
+
+    fn header(&self) -> *mut H {
+        //  Safety:
+        //  - At least `size_of::<H>()` bytes are allocated ahead of the pointer.
+        //  - We know that H will be aligned because the middle pointer is aligned to the greater
+        //    of the alignment of the header and the data and the header size includes the padding
+        //    needed to align the header. Subtracting the header size from the aligned data pointer
+        //    will always result in an aligned header pointer, it just may not point to the
+        //    beginning of the allocation.
+        unsafe { self.0.as_ptr().sub(Self::header_size()) as *mut H }
+    }
+
+    fn value(&self) -> *mut u8 {
+        self.0.as_ptr()
+    }
+
+    const fn header_size() -> usize {
+        mem::size_of::<H>()
+    }
+
+    fn alloc_layout(value_layout: Layout) -> Result<(Layout, usize), LayoutError> {
+        Layout::new::<H>().extend(value_layout)
+    }
+}
diff --git a/rust/alloc/collections/mod.rs b/rust/alloc/collections/mod.rs
new file mode 100644
index 000000000000..1eec265b28f8
--- /dev/null
+++ b/rust/alloc/collections/mod.rs
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! Collection types.
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[cfg(not(no_global_oom_handling))]
+pub mod binary_heap;
+#[cfg(not(no_global_oom_handling))]
+mod btree;
+#[cfg(not(no_global_oom_handling))]
+pub mod linked_list;
+#[cfg(not(no_global_oom_handling))]
+pub mod vec_deque;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub mod btree_map {
+    //! An ordered map based on a B-Tree.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub use super::btree::map::*;
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub mod btree_set {
+    //! An ordered set based on a B-Tree.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub use super::btree::set::*;
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use binary_heap::BinaryHeap;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use btree_map::BTreeMap;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use btree_set::BTreeSet;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use linked_list::LinkedList;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[doc(no_inline)]
+pub use vec_deque::VecDeque;
+
+use crate::alloc::{Layout, LayoutError};
+use core::fmt::Display;
+
+/// The error type for `try_reserve` methods.
+#[derive(Clone, PartialEq, Eq, Debug)]
+#[stable(feature = "try_reserve", since = "1.57.0")]
+pub struct TryReserveError {
+    kind: TryReserveErrorKind,
+}
+
+impl TryReserveError {
+    /// Details about the allocation that caused the error
+    #[inline]
+    #[must_use]
+    #[unstable(
+        feature = "try_reserve_kind",
+        reason = "Uncertain how much info should be exposed",
+        issue = "48043"
+    )]
+    pub fn kind(&self) -> TryReserveErrorKind {
+        self.kind.clone()
+    }
+}
+
+/// Details of the allocation that caused a `TryReserveError`
+#[derive(Clone, PartialEq, Eq, Debug)]
+#[unstable(
+    feature = "try_reserve_kind",
+    reason = "Uncertain how much info should be exposed",
+    issue = "48043"
+)]
+pub enum TryReserveErrorKind {
+    /// Error due to the computed capacity exceeding the collection's maximum
+    /// (usually `isize::MAX` bytes).
+    CapacityOverflow,
+
+    /// The memory allocator returned an error
+    AllocError {
+        /// The layout of allocation request that failed
+        layout: Layout,
+
+        #[doc(hidden)]
+        #[unstable(
+            feature = "container_error_extra",
+            issue = "none",
+            reason = "\
+            Enable exposing the allocator’s custom error value \
+            if an associated type is added in the future: \
+            https://github.com/rust-lang/wg-allocators/issues/23"
+        )]
+        non_exhaustive: (),
+    },
+}
+
+#[unstable(
+    feature = "try_reserve_kind",
+    reason = "Uncertain how much info should be exposed",
+    issue = "48043"
+)]
+impl From<TryReserveErrorKind> for TryReserveError {
+    #[inline]
+    fn from(kind: TryReserveErrorKind) -> Self {
+        Self { kind }
+    }
+}
+
+#[unstable(feature = "try_reserve_kind", reason = "new API", issue = "48043")]
+impl From<LayoutError> for TryReserveErrorKind {
+    /// Always evaluates to [`TryReserveErrorKind::CapacityOverflow`].
+    #[inline]
+    fn from(_: LayoutError) -> Self {
+        TryReserveErrorKind::CapacityOverflow
+    }
+}
+
+#[stable(feature = "try_reserve", since = "1.57.0")]
+impl Display for TryReserveError {
+    fn fmt(
+        &self,
+        fmt: &mut core::fmt::Formatter<'_>,
+    ) -> core::result::Result<(), core::fmt::Error> {
+        fmt.write_str("memory allocation failed")?;
+        let reason = match self.kind {
+            TryReserveErrorKind::CapacityOverflow => {
+                " because the computed capacity exceeded the collection's maximum"
+            }
+            TryReserveErrorKind::AllocError { .. } => {
+                " because the memory allocator returned a error"
+            }
+        };
+        fmt.write_str(reason)
+    }
+}
+
+/// An intermediate trait for specialization of `Extend`.
+#[doc(hidden)]
+trait SpecExtend<I: IntoIterator> {
+    /// Extends `self` with the contents of the given iterator.
+    fn spec_extend(&mut self, iter: I);
+}
diff --git a/rust/alloc/ffi/c_str.rs b/rust/alloc/ffi/c_str.rs
new file mode 100644
index 000000000000..5e2f4073771a
--- /dev/null
+++ b/rust/alloc/ffi/c_str.rs
@@ -0,0 +1,1203 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+#[cfg(test)]
+mod tests;
+
+use crate::borrow::{Cow, ToOwned};
+use crate::boxed::Box;
+use crate::rc::Rc;
+use crate::slice::hack::into_vec;
+use crate::string::String;
+use crate::vec::Vec;
+use core::borrow::Borrow;
+use core::ffi::{c_char, CStr};
+use core::fmt;
+use core::mem;
+use core::num::NonZeroU8;
+use core::ops;
+use core::ptr;
+use core::slice;
+use core::slice::memchr;
+use core::str::{self, Utf8Error};
+
+#[cfg(target_has_atomic = "ptr")]
+use crate::sync::Arc;
+
+/// A type representing an owned, C-compatible, nul-terminated string with no nul bytes in the
+/// middle.
+///
+/// This type serves the purpose of being able to safely generate a
+/// C-compatible string from a Rust byte slice or vector. An instance of this
+/// type is a static guarantee that the underlying bytes contain no interior 0
+/// bytes ("nul characters") and that the final byte is 0 ("nul terminator").
+///
+/// `CString` is to <code>&[CStr]</code> as [`String`] is to <code>&[str]</code>: the former
+/// in each pair are owned strings; the latter are borrowed
+/// references.
+///
+/// # Creating a `CString`
+///
+/// A `CString` is created from either a byte slice or a byte vector,
+/// or anything that implements <code>[Into]<[Vec]<[u8]>></code> (for
+/// example, you can build a `CString` straight out of a [`String`] or
+/// a <code>&[str]</code>, since both implement that trait).
+///
+/// The [`CString::new`] method will actually check that the provided <code>&[[u8]]</code>
+/// does not have 0 bytes in the middle, and return an error if it
+/// finds one.
+///
+/// # Extracting a raw pointer to the whole C string
+///
+/// `CString` implements an [`as_ptr`][`CStr::as_ptr`] method through the [`Deref`]
+/// trait. This method will give you a `*const c_char` which you can
+/// feed directly to extern functions that expect a nul-terminated
+/// string, like C's `strdup()`. Notice that [`as_ptr`][`CStr::as_ptr`] returns a
+/// read-only pointer; if the C code writes to it, that causes
+/// undefined behavior.
+///
+/// # Extracting a slice of the whole C string
+///
+/// Alternatively, you can obtain a <code>&[[u8]]</code> slice from a
+/// `CString` with the [`CString::as_bytes`] method. Slices produced in this
+/// way do *not* contain the trailing nul terminator. This is useful
+/// when you will be calling an extern function that takes a `*const
+/// u8` argument which is not necessarily nul-terminated, plus another
+/// argument with the length of the string — like C's `strndup()`.
+/// You can of course get the slice's length with its
+/// [`len`][slice::len] method.
+///
+/// If you need a <code>&[[u8]]</code> slice *with* the nul terminator, you
+/// can use [`CString::as_bytes_with_nul`] instead.
+///
+/// Once you have the kind of slice you need (with or without a nul
+/// terminator), you can call the slice's own
+/// [`as_ptr`][slice::as_ptr] method to get a read-only raw pointer to pass to
+/// extern functions. See the documentation for that function for a
+/// discussion on ensuring the lifetime of the raw pointer.
+///
+/// [str]: prim@str "str"
+/// [`Deref`]: ops::Deref
+///
+/// # Examples
+///
+/// ```ignore (extern-declaration)
+/// # fn main() {
+/// use std::ffi::CString;
+/// use std::os::raw::c_char;
+///
+/// extern "C" {
+///     fn my_printer(s: *const c_char);
+/// }
+///
+/// // We are certain that our string doesn't have 0 bytes in the middle,
+/// // so we can .expect()
+/// let c_to_print = CString::new("Hello, world!").expect("CString::new failed");
+/// unsafe {
+///     my_printer(c_to_print.as_ptr());
+/// }
+/// # }
+/// ```
+///
+/// # Safety
+///
+/// `CString` is intended for working with traditional C-style strings
+/// (a sequence of non-nul bytes terminated by a single nul byte); the
+/// primary use case for these kinds of strings is interoperating with C-like
+/// code. Often you will need to transfer ownership to/from that external
+/// code. It is strongly recommended that you thoroughly read through the
+/// documentation of `CString` before use, as improper ownership management
+/// of `CString` instances can lead to invalid memory accesses, memory leaks,
+/// and other memory errors.
+#[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone)]
+#[cfg_attr(not(test), rustc_diagnostic_item = "cstring_type")]
+#[unstable(feature = "alloc_c_string", issue = "94079")]
+pub struct CString {
+    // Invariant 1: the slice ends with a zero byte and has a length of at least one.
+    // Invariant 2: the slice contains only one zero byte.
+    // Improper usage of unsafe function can break Invariant 2, but not Invariant 1.
+    inner: Box<[u8]>,
+}
+
+/// An error indicating that an interior nul byte was found.
+///
+/// While Rust strings may contain nul bytes in the middle, C strings
+/// can't, as that byte would effectively truncate the string.
+///
+/// This error is created by the [`new`][`CString::new`] method on
+/// [`CString`]. See its documentation for more.
+///
+/// # Examples
+///
+/// ```
+/// use std::ffi::{CString, NulError};
+///
+/// let _: NulError = CString::new(b"f\0oo".to_vec()).unwrap_err();
+/// ```
+#[derive(Clone, PartialEq, Eq, Debug)]
+#[unstable(feature = "alloc_c_string", issue = "94079")]
+pub struct NulError(usize, Vec<u8>);
+
+#[derive(Clone, PartialEq, Eq, Debug)]
+enum FromBytesWithNulErrorKind {
+    InteriorNul(usize),
+    NotNulTerminated,
+}
+
+/// An error indicating that a nul byte was not in the expected position.
+///
+/// The vector used to create a [`CString`] must have one and only one nul byte,
+/// positioned at the end.
+///
+/// This error is created by the [`CString::from_vec_with_nul`] method.
+/// See its documentation for more.
+///
+/// # Examples
+///
+/// ```
+/// use std::ffi::{CString, FromVecWithNulError};
+///
+/// let _: FromVecWithNulError = CString::from_vec_with_nul(b"f\0oo".to_vec()).unwrap_err();
+/// ```
+#[derive(Clone, PartialEq, Eq, Debug)]
+#[unstable(feature = "alloc_c_string", issue = "94079")]
+pub struct FromVecWithNulError {
+    error_kind: FromBytesWithNulErrorKind,
+    bytes: Vec<u8>,
+}
+
+#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
+impl FromVecWithNulError {
+    /// Returns a slice of [`u8`]s bytes that were attempted to convert to a [`CString`].
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// // Some invalid bytes in a vector
+    /// let bytes = b"f\0oo".to_vec();
+    ///
+    /// let value = CString::from_vec_with_nul(bytes.clone());
+    ///
+    /// assert_eq!(&bytes[..], value.unwrap_err().as_bytes());
+    /// ```
+    #[must_use]
+    #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
+    pub fn as_bytes(&self) -> &[u8] {
+        &self.bytes[..]
+    }
+
+    /// Returns the bytes that were attempted to convert to a [`CString`].
+    ///
+    /// This method is carefully constructed to avoid allocation. It will
+    /// consume the error, moving out the bytes, so that a copy of the bytes
+    /// does not need to be made.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// // Some invalid bytes in a vector
+    /// let bytes = b"f\0oo".to_vec();
+    ///
+    /// let value = CString::from_vec_with_nul(bytes.clone());
+    ///
+    /// assert_eq!(bytes, value.unwrap_err().into_bytes());
+    /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
+    pub fn into_bytes(self) -> Vec<u8> {
+        self.bytes
+    }
+}
+
+/// An error indicating invalid UTF-8 when converting a [`CString`] into a [`String`].
+///
+/// `CString` is just a wrapper over a buffer of bytes with a nul terminator;
+/// [`CString::into_string`] performs UTF-8 validation on those bytes and may
+/// return this error.
+///
+/// This `struct` is created by [`CString::into_string()`]. See
+/// its documentation for more.
+#[derive(Clone, PartialEq, Eq, Debug)]
+#[unstable(feature = "alloc_c_string", issue = "94079")]
+pub struct IntoStringError {
+    inner: CString,
+    error: Utf8Error,
+}
+
+impl CString {
+    /// Creates a new C-compatible string from a container of bytes.
+    ///
+    /// This function will consume the provided data and use the
+    /// underlying bytes to construct a new string, ensuring that
+    /// there is a trailing 0 byte. This trailing 0 byte will be
+    /// appended by this function; the provided data should *not*
+    /// contain any 0 bytes in it.
+    ///
+    /// # Examples
+    ///
+    /// ```ignore (extern-declaration)
+    /// use std::ffi::CString;
+    /// use std::os::raw::c_char;
+    ///
+    /// extern "C" { fn puts(s: *const c_char); }
+    ///
+    /// let to_print = CString::new("Hello!").expect("CString::new failed");
+    /// unsafe {
+    ///     puts(to_print.as_ptr());
+    /// }
+    /// ```
+    ///
+    /// # Errors
+    ///
+    /// This function will return an error if the supplied bytes contain an
+    /// internal 0 byte. The [`NulError`] returned will contain the bytes as well as
+    /// the position of the nul byte.
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn new<T: Into<Vec<u8>>>(t: T) -> Result<CString, NulError> {
+        trait SpecNewImpl {
+            fn spec_new_impl(self) -> Result<CString, NulError>;
+        }
+
+        impl<T: Into<Vec<u8>>> SpecNewImpl for T {
+            default fn spec_new_impl(self) -> Result<CString, NulError> {
+                let bytes: Vec<u8> = self.into();
+                match memchr::memchr(0, &bytes) {
+                    Some(i) => Err(NulError(i, bytes)),
+                    None => Ok(unsafe { CString::_from_vec_unchecked(bytes) }),
+                }
+            }
+        }
+
+        // Specialization for avoiding reallocation
+        #[inline(always)] // Without that it is not inlined into specializations
+        fn spec_new_impl_bytes(bytes: &[u8]) -> Result<CString, NulError> {
+            // We cannot have such large slice that we would overflow here
+            // but using `checked_add` allows LLVM to assume that capacity never overflows
+            // and generate twice shorter code.
+            // `saturating_add` doesn't help for some reason.
+            let capacity = bytes.len().checked_add(1).unwrap();
+
+            // Allocate before validation to avoid duplication of allocation code.
+            // We still need to allocate and copy memory even if we get an error.
+            let mut buffer = Vec::with_capacity(capacity);
+            buffer.extend(bytes);
+
+            // Check memory of self instead of new buffer.
+            // This allows better optimizations if lto enabled.
+            match memchr::memchr(0, bytes) {
+                Some(i) => Err(NulError(i, buffer)),
+                None => Ok(unsafe { CString::_from_vec_unchecked(buffer) }),
+            }
+        }
+
+        impl SpecNewImpl for &'_ [u8] {
+            fn spec_new_impl(self) -> Result<CString, NulError> {
+                spec_new_impl_bytes(self)
+            }
+        }
+
+        impl SpecNewImpl for &'_ str {
+            fn spec_new_impl(self) -> Result<CString, NulError> {
+                spec_new_impl_bytes(self.as_bytes())
+            }
+        }
+
+        impl SpecNewImpl for &'_ mut [u8] {
+            fn spec_new_impl(self) -> Result<CString, NulError> {
+                spec_new_impl_bytes(self)
+            }
+        }
+
+        t.spec_new_impl()
+    }
+
+    /// Creates a C-compatible string by consuming a byte vector,
+    /// without checking for interior 0 bytes.
+    ///
+    /// Trailing 0 byte will be appended by this function.
+    ///
+    /// This method is equivalent to [`CString::new`] except that no runtime
+    /// assertion is made that `v` contains no 0 bytes, and it requires an
+    /// actual byte vector, not anything that can be converted to one with Into.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let raw = b"foo".to_vec();
+    /// unsafe {
+    ///     let c_string = CString::from_vec_unchecked(raw);
+    /// }
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub unsafe fn from_vec_unchecked(v: Vec<u8>) -> Self {
+        debug_assert!(memchr::memchr(0, &v).is_none());
+        unsafe { Self::_from_vec_unchecked(v) }
+    }
+
+    unsafe fn _from_vec_unchecked(mut v: Vec<u8>) -> Self {
+        v.reserve_exact(1);
+        v.push(0);
+        Self { inner: v.into_boxed_slice() }
+    }
+
+    /// Retakes ownership of a `CString` that was transferred to C via
+    /// [`CString::into_raw`].
+    ///
+    /// Additionally, the length of the string will be recalculated from the pointer.
+    ///
+    /// # Safety
+    ///
+    /// This should only ever be called with a pointer that was earlier
+    /// obtained by calling [`CString::into_raw`]. Other usage (e.g., trying to take
+    /// ownership of a string that was allocated by foreign code) is likely to lead
+    /// to undefined behavior or allocator corruption.
+    ///
+    /// It should be noted that the length isn't just "recomputed," but that
+    /// the recomputed length must match the original length from the
+    /// [`CString::into_raw`] call. This means the [`CString::into_raw`]/`from_raw`
+    /// methods should not be used when passing the string to C functions that can
+    /// modify the string's length.
+    ///
+    /// > **Note:** If you need to borrow a string that was allocated by
+    /// > foreign code, use [`CStr`]. If you need to take ownership of
+    /// > a string that was allocated by foreign code, you will need to
+    /// > make your own provisions for freeing it appropriately, likely
+    /// > with the foreign code's API to do that.
+    ///
+    /// # Examples
+    ///
+    /// Creates a `CString`, pass ownership to an `extern` function (via raw pointer), then retake
+    /// ownership with `from_raw`:
+    ///
+    /// ```ignore (extern-declaration)
+    /// use std::ffi::CString;
+    /// use std::os::raw::c_char;
+    ///
+    /// extern "C" {
+    ///     fn some_extern_function(s: *mut c_char);
+    /// }
+    ///
+    /// let c_string = CString::new("Hello!").expect("CString::new failed");
+    /// let raw = c_string.into_raw();
+    /// unsafe {
+    ///     some_extern_function(raw);
+    ///     let c_string = CString::from_raw(raw);
+    /// }
+    /// ```
+    #[must_use = "call `drop(from_raw(ptr))` if you intend to drop the `CString`"]
+    #[stable(feature = "cstr_memory", since = "1.4.0")]
+    pub unsafe fn from_raw(ptr: *mut c_char) -> CString {
+        // SAFETY: This is called with a pointer that was obtained from a call
+        // to `CString::into_raw` and the length has not been modified. As such,
+        // we know there is a NUL byte (and only one) at the end and that the
+        // information about the size of the allocation is correct on Rust's
+        // side.
+        unsafe {
+            extern "C" {
+                /// Provided by libc or compiler_builtins.
+                fn strlen(s: *const c_char) -> usize;
+            }
+            let len = strlen(ptr) + 1; // Including the NUL byte
+            let slice = slice::from_raw_parts_mut(ptr, len as usize);
+            CString { inner: Box::from_raw(slice as *mut [c_char] as *mut [u8]) }
+        }
+    }
+
+    /// Consumes the `CString` and transfers ownership of the string to a C caller.
+    ///
+    /// The pointer which this function returns must be returned to Rust and reconstituted using
+    /// [`CString::from_raw`] to be properly deallocated. Specifically, one
+    /// should *not* use the standard C `free()` function to deallocate
+    /// this string.
+    ///
+    /// Failure to call [`CString::from_raw`] will lead to a memory leak.
+    ///
+    /// The C side must **not** modify the length of the string (by writing a
+    /// `null` somewhere inside the string or removing the final one) before
+    /// it makes it back into Rust using [`CString::from_raw`]. See the safety section
+    /// in [`CString::from_raw`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let c_string = CString::new("foo").expect("CString::new failed");
+    ///
+    /// let ptr = c_string.into_raw();
+    ///
+    /// unsafe {
+    ///     assert_eq!(b'f', *ptr as u8);
+    ///     assert_eq!(b'o', *ptr.offset(1) as u8);
+    ///     assert_eq!(b'o', *ptr.offset(2) as u8);
+    ///     assert_eq!(b'\0', *ptr.offset(3) as u8);
+    ///
+    ///     // retake pointer to free memory
+    ///     let _ = CString::from_raw(ptr);
+    /// }
+    /// ```
+    #[inline]
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "cstr_memory", since = "1.4.0")]
+    pub fn into_raw(self) -> *mut c_char {
+        Box::into_raw(self.into_inner()) as *mut c_char
+    }
+
+    /// Converts the `CString` into a [`String`] if it contains valid UTF-8 data.
+    ///
+    /// On failure, ownership of the original `CString` is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let valid_utf8 = vec![b'f', b'o', b'o'];
+    /// let cstring = CString::new(valid_utf8).expect("CString::new failed");
+    /// assert_eq!(cstring.into_string().expect("into_string() call failed"), "foo");
+    ///
+    /// let invalid_utf8 = vec![b'f', 0xff, b'o', b'o'];
+    /// let cstring = CString::new(invalid_utf8).expect("CString::new failed");
+    /// let err = cstring.into_string().err().expect("into_string().err() failed");
+    /// assert_eq!(err.utf8_error().valid_up_to(), 1);
+    /// ```
+    #[stable(feature = "cstring_into", since = "1.7.0")]
+    pub fn into_string(self) -> Result<String, IntoStringError> {
+        String::from_utf8(self.into_bytes()).map_err(|e| IntoStringError {
+            error: e.utf8_error(),
+            inner: unsafe { Self::_from_vec_unchecked(e.into_bytes()) },
+        })
+    }
+
+    /// Consumes the `CString` and returns the underlying byte buffer.
+    ///
+    /// The returned buffer does **not** contain the trailing nul
+    /// terminator, and it is guaranteed to not have any interior nul
+    /// bytes.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let c_string = CString::new("foo").expect("CString::new failed");
+    /// let bytes = c_string.into_bytes();
+    /// assert_eq!(bytes, vec![b'f', b'o', b'o']);
+    /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "cstring_into", since = "1.7.0")]
+    pub fn into_bytes(self) -> Vec<u8> {
+        let mut vec = into_vec(self.into_inner());
+        let _nul = vec.pop();
+        debug_assert_eq!(_nul, Some(0u8));
+        vec
+    }
+
+    /// Equivalent to [`CString::into_bytes()`] except that the
+    /// returned vector includes the trailing nul terminator.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let c_string = CString::new("foo").expect("CString::new failed");
+    /// let bytes = c_string.into_bytes_with_nul();
+    /// assert_eq!(bytes, vec![b'f', b'o', b'o', b'\0']);
+    /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "cstring_into", since = "1.7.0")]
+    pub fn into_bytes_with_nul(self) -> Vec<u8> {
+        into_vec(self.into_inner())
+    }
+
+    /// Returns the contents of this `CString` as a slice of bytes.
+    ///
+    /// The returned slice does **not** contain the trailing nul
+    /// terminator, and it is guaranteed to not have any interior nul
+    /// bytes. If you need the nul terminator, use
+    /// [`CString::as_bytes_with_nul`] instead.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let c_string = CString::new("foo").expect("CString::new failed");
+    /// let bytes = c_string.as_bytes();
+    /// assert_eq!(bytes, &[b'f', b'o', b'o']);
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn as_bytes(&self) -> &[u8] {
+        // SAFETY: CString has a length at least 1
+        unsafe { self.inner.get_unchecked(..self.inner.len() - 1) }
+    }
+
+    /// Equivalent to [`CString::as_bytes()`] except that the
+    /// returned slice includes the trailing nul terminator.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let c_string = CString::new("foo").expect("CString::new failed");
+    /// let bytes = c_string.as_bytes_with_nul();
+    /// assert_eq!(bytes, &[b'f', b'o', b'o', b'\0']);
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn as_bytes_with_nul(&self) -> &[u8] {
+        &self.inner
+    }
+
+    /// Extracts a [`CStr`] slice containing the entire string.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::{CString, CStr};
+    ///
+    /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed");
+    /// let cstr = c_string.as_c_str();
+    /// assert_eq!(cstr,
+    ///            CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"));
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "as_c_str", since = "1.20.0")]
+    pub fn as_c_str(&self) -> &CStr {
+        &*self
+    }
+
+    /// Converts this `CString` into a boxed [`CStr`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::{CString, CStr};
+    ///
+    /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed");
+    /// let boxed = c_string.into_boxed_c_str();
+    /// assert_eq!(&*boxed,
+    ///            CStr::from_bytes_with_nul(b"foo\0").expect("CStr::from_bytes_with_nul failed"));
+    /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "into_boxed_c_str", since = "1.20.0")]
+    pub fn into_boxed_c_str(self) -> Box<CStr> {
+        unsafe { Box::from_raw(Box::into_raw(self.into_inner()) as *mut CStr) }
+    }
+
+    /// Bypass "move out of struct which implements [`Drop`] trait" restriction.
+    #[inline]
+    fn into_inner(self) -> Box<[u8]> {
+        // Rationale: `mem::forget(self)` invalidates the previous call to `ptr::read(&self.inner)`
+        // so we use `ManuallyDrop` to ensure `self` is not dropped.
+        // Then we can return the box directly without invalidating it.
+        // See https://github.com/rust-lang/rust/issues/62553.
+        let this = mem::ManuallyDrop::new(self);
+        unsafe { ptr::read(&this.inner) }
+    }
+
+    /// Converts a <code>[Vec]<[u8]></code> to a [`CString`] without checking the
+    /// invariants on the given [`Vec`].
+    ///
+    /// # Safety
+    ///
+    /// The given [`Vec`] **must** have one nul byte as its last element.
+    /// This means it cannot be empty nor have any other nul byte anywhere else.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    /// assert_eq!(
+    ///     unsafe { CString::from_vec_with_nul_unchecked(b"abc\0".to_vec()) },
+    ///     unsafe { CString::from_vec_unchecked(b"abc".to_vec()) }
+    /// );
+    /// ```
+    #[must_use]
+    #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
+    pub unsafe fn from_vec_with_nul_unchecked(v: Vec<u8>) -> Self {
+        debug_assert!(memchr::memchr(0, &v).unwrap() + 1 == v.len());
+        unsafe { Self::_from_vec_with_nul_unchecked(v) }
+    }
+
+    unsafe fn _from_vec_with_nul_unchecked(v: Vec<u8>) -> Self {
+        Self { inner: v.into_boxed_slice() }
+    }
+
+    /// Attempts to converts a <code>[Vec]<[u8]></code> to a [`CString`].
+    ///
+    /// Runtime checks are present to ensure there is only one nul byte in the
+    /// [`Vec`], its last element.
+    ///
+    /// # Errors
+    ///
+    /// If a nul byte is present and not the last element or no nul bytes
+    /// is present, an error will be returned.
+    ///
+    /// # Examples
+    ///
+    /// A successful conversion will produce the same result as [`CString::new`]
+    /// when called without the ending nul byte.
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    /// assert_eq!(
+    ///     CString::from_vec_with_nul(b"abc\0".to_vec())
+    ///         .expect("CString::from_vec_with_nul failed"),
+    ///     CString::new(b"abc".to_vec()).expect("CString::new failed")
+    /// );
+    /// ```
+    ///
+    /// An incorrectly formatted [`Vec`] will produce an error.
+    ///
+    /// ```
+    /// use std::ffi::{CString, FromVecWithNulError};
+    /// // Interior nul byte
+    /// let _: FromVecWithNulError = CString::from_vec_with_nul(b"a\0bc".to_vec()).unwrap_err();
+    /// // No nul byte
+    /// let _: FromVecWithNulError = CString::from_vec_with_nul(b"abc".to_vec()).unwrap_err();
+    /// ```
+    #[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
+    pub fn from_vec_with_nul(v: Vec<u8>) -> Result<Self, FromVecWithNulError> {
+        let nul_pos = memchr::memchr(0, &v);
+        match nul_pos {
+            Some(nul_pos) if nul_pos + 1 == v.len() => {
+                // SAFETY: We know there is only one nul byte, at the end
+                // of the vec.
+                Ok(unsafe { Self::_from_vec_with_nul_unchecked(v) })
+            }
+            Some(nul_pos) => Err(FromVecWithNulError {
+                error_kind: FromBytesWithNulErrorKind::InteriorNul(nul_pos),
+                bytes: v,
+            }),
+            None => Err(FromVecWithNulError {
+                error_kind: FromBytesWithNulErrorKind::NotNulTerminated,
+                bytes: v,
+            }),
+        }
+    }
+}
+
+// Turns this `CString` into an empty string to prevent
+// memory-unsafe code from working by accident. Inline
+// to prevent LLVM from optimizing it away in debug builds.
+#[stable(feature = "cstring_drop", since = "1.13.0")]
+impl Drop for CString {
+    #[inline]
+    fn drop(&mut self) {
+        unsafe {
+            *self.inner.get_unchecked_mut(0) = 0;
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Deref for CString {
+    type Target = CStr;
+
+    #[inline]
+    fn deref(&self) -> &CStr {
+        unsafe { CStr::from_bytes_with_nul_unchecked(self.as_bytes_with_nul()) }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Debug for CString {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(&**self, f)
+    }
+}
+
+#[stable(feature = "cstring_into", since = "1.7.0")]
+impl From<CString> for Vec<u8> {
+    /// Converts a [`CString`] into a <code>[Vec]<[u8]></code>.
+    ///
+    /// The conversion consumes the [`CString`], and removes the terminating NUL byte.
+    #[inline]
+    fn from(s: CString) -> Vec<u8> {
+        s.into_bytes()
+    }
+}
+
+#[stable(feature = "cstr_default", since = "1.10.0")]
+impl Default for CString {
+    /// Creates an empty `CString`.
+    fn default() -> CString {
+        let a: &CStr = Default::default();
+        a.to_owned()
+    }
+}
+
+#[stable(feature = "cstr_borrow", since = "1.3.0")]
+impl Borrow<CStr> for CString {
+    #[inline]
+    fn borrow(&self) -> &CStr {
+        self
+    }
+}
+
+#[stable(feature = "cstring_from_cow_cstr", since = "1.28.0")]
+impl<'a> From<Cow<'a, CStr>> for CString {
+    /// Converts a `Cow<'a, CStr>` into a `CString`, by copying the contents if they are
+    /// borrowed.
+    #[inline]
+    fn from(s: Cow<'a, CStr>) -> Self {
+        s.into_owned()
+    }
+}
+
+#[cfg(not(test))]
+#[stable(feature = "box_from_c_str", since = "1.17.0")]
+impl From<&CStr> for Box<CStr> {
+    /// Converts a `&CStr` into a `Box<CStr>`,
+    /// by copying the contents into a newly allocated [`Box`].
+    fn from(s: &CStr) -> Box<CStr> {
+        let boxed: Box<[u8]> = Box::from(s.to_bytes_with_nul());
+        unsafe { Box::from_raw(Box::into_raw(boxed) as *mut CStr) }
+    }
+}
+
+#[stable(feature = "box_from_cow", since = "1.45.0")]
+impl From<Cow<'_, CStr>> for Box<CStr> {
+    /// Converts a `Cow<'a, CStr>` into a `Box<CStr>`,
+    /// by copying the contents if they are borrowed.
+    #[inline]
+    fn from(cow: Cow<'_, CStr>) -> Box<CStr> {
+        match cow {
+            Cow::Borrowed(s) => Box::from(s),
+            Cow::Owned(s) => Box::from(s),
+        }
+    }
+}
+
+#[stable(feature = "c_string_from_box", since = "1.18.0")]
+impl From<Box<CStr>> for CString {
+    /// Converts a <code>[Box]<[CStr]></code> into a [`CString`] without copying or allocating.
+    #[inline]
+    fn from(s: Box<CStr>) -> CString {
+        let raw = Box::into_raw(s) as *mut [u8];
+        CString { inner: unsafe { Box::from_raw(raw) } }
+    }
+}
+
+#[stable(feature = "cstring_from_vec_of_nonzerou8", since = "1.43.0")]
+impl From<Vec<NonZeroU8>> for CString {
+    /// Converts a <code>[Vec]<[NonZeroU8]></code> into a [`CString`] without
+    /// copying nor checking for inner null bytes.
+    #[inline]
+    fn from(v: Vec<NonZeroU8>) -> CString {
+        unsafe {
+            // Transmute `Vec<NonZeroU8>` to `Vec<u8>`.
+            let v: Vec<u8> = {
+                // SAFETY:
+                //   - transmuting between `NonZeroU8` and `u8` is sound;
+                //   - `alloc::Layout<NonZeroU8> == alloc::Layout<u8>`.
+                let (ptr, len, cap): (*mut NonZeroU8, _, _) = Vec::into_raw_parts(v);
+                Vec::from_raw_parts(ptr.cast::<u8>(), len, cap)
+            };
+            // SAFETY: `v` cannot contain null bytes, given the type-level
+            // invariant of `NonZeroU8`.
+            Self::_from_vec_unchecked(v)
+        }
+    }
+}
+
+#[cfg(not(test))]
+#[stable(feature = "more_box_slice_clone", since = "1.29.0")]
+impl Clone for Box<CStr> {
+    #[inline]
+    fn clone(&self) -> Self {
+        (**self).into()
+    }
+}
+
+#[stable(feature = "box_from_c_string", since = "1.20.0")]
+impl From<CString> for Box<CStr> {
+    /// Converts a [`CString`] into a <code>[Box]<[CStr]></code> without copying or allocating.
+    #[inline]
+    fn from(s: CString) -> Box<CStr> {
+        s.into_boxed_c_str()
+    }
+}
+
+#[stable(feature = "cow_from_cstr", since = "1.28.0")]
+impl<'a> From<CString> for Cow<'a, CStr> {
+    /// Converts a [`CString`] into an owned [`Cow`] without copying or allocating.
+    #[inline]
+    fn from(s: CString) -> Cow<'a, CStr> {
+        Cow::Owned(s)
+    }
+}
+
+#[stable(feature = "cow_from_cstr", since = "1.28.0")]
+impl<'a> From<&'a CStr> for Cow<'a, CStr> {
+    /// Converts a [`CStr`] into a borrowed [`Cow`] without copying or allocating.
+    #[inline]
+    fn from(s: &'a CStr) -> Cow<'a, CStr> {
+        Cow::Borrowed(s)
+    }
+}
+
+#[stable(feature = "cow_from_cstr", since = "1.28.0")]
+impl<'a> From<&'a CString> for Cow<'a, CStr> {
+    /// Converts a `&`[`CString`] into a borrowed [`Cow`] without copying or allocating.
+    #[inline]
+    fn from(s: &'a CString) -> Cow<'a, CStr> {
+        Cow::Borrowed(s.as_c_str())
+    }
+}
+
+#[cfg(target_has_atomic = "ptr")]
+#[stable(feature = "shared_from_slice2", since = "1.24.0")]
+impl From<CString> for Arc<CStr> {
+    /// Converts a [`CString`] into an <code>[Arc]<[CStr]></code> by moving the [`CString`]
+    /// data into a new [`Arc`] buffer.
+    #[inline]
+    fn from(s: CString) -> Arc<CStr> {
+        let arc: Arc<[u8]> = Arc::from(s.into_inner());
+        unsafe { Arc::from_raw(Arc::into_raw(arc) as *const CStr) }
+    }
+}
+
+#[cfg(target_has_atomic = "ptr")]
+#[stable(feature = "shared_from_slice2", since = "1.24.0")]
+impl From<&CStr> for Arc<CStr> {
+    /// Converts a `&CStr` into a `Arc<CStr>`,
+    /// by copying the contents into a newly allocated [`Arc`].
+    #[inline]
+    fn from(s: &CStr) -> Arc<CStr> {
+        let arc: Arc<[u8]> = Arc::from(s.to_bytes_with_nul());
+        unsafe { Arc::from_raw(Arc::into_raw(arc) as *const CStr) }
+    }
+}
+
+#[stable(feature = "shared_from_slice2", since = "1.24.0")]
+impl From<CString> for Rc<CStr> {
+    /// Converts a [`CString`] into an <code>[Rc]<[CStr]></code> by moving the [`CString`]
+    /// data into a new [`Arc`] buffer.
+    #[inline]
+    fn from(s: CString) -> Rc<CStr> {
+        let rc: Rc<[u8]> = Rc::from(s.into_inner());
+        unsafe { Rc::from_raw(Rc::into_raw(rc) as *const CStr) }
+    }
+}
+
+#[stable(feature = "shared_from_slice2", since = "1.24.0")]
+impl From<&CStr> for Rc<CStr> {
+    /// Converts a `&CStr` into a `Rc<CStr>`,
+    /// by copying the contents into a newly allocated [`Rc`].
+    #[inline]
+    fn from(s: &CStr) -> Rc<CStr> {
+        let rc: Rc<[u8]> = Rc::from(s.to_bytes_with_nul());
+        unsafe { Rc::from_raw(Rc::into_raw(rc) as *const CStr) }
+    }
+}
+
+#[cfg(not(test))]
+#[stable(feature = "default_box_extra", since = "1.17.0")]
+impl Default for Box<CStr> {
+    fn default() -> Box<CStr> {
+        let boxed: Box<[u8]> = Box::from([0]);
+        unsafe { Box::from_raw(Box::into_raw(boxed) as *mut CStr) }
+    }
+}
+
+impl NulError {
+    /// Returns the position of the nul byte in the slice that caused
+    /// [`CString::new`] to fail.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let nul_error = CString::new("foo\0bar").unwrap_err();
+    /// assert_eq!(nul_error.nul_position(), 3);
+    ///
+    /// let nul_error = CString::new("foo bar\0").unwrap_err();
+    /// assert_eq!(nul_error.nul_position(), 7);
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn nul_position(&self) -> usize {
+        self.0
+    }
+
+    /// Consumes this error, returning the underlying vector of bytes which
+    /// generated the error in the first place.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let nul_error = CString::new("foo\0bar").unwrap_err();
+    /// assert_eq!(nul_error.into_vec(), b"foo\0bar");
+    /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_vec(self) -> Vec<u8> {
+        self.1
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for NulError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "nul byte found in provided data at position: {}", self.0)
+    }
+}
+
+#[stable(feature = "cstring_from_vec_with_nul", since = "1.58.0")]
+impl fmt::Display for FromVecWithNulError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.error_kind {
+            FromBytesWithNulErrorKind::InteriorNul(pos) => {
+                write!(f, "data provided contains an interior nul byte at pos {pos}")
+            }
+            FromBytesWithNulErrorKind::NotNulTerminated => {
+                write!(f, "data provided is not nul terminated")
+            }
+        }
+    }
+}
+
+impl IntoStringError {
+    /// Consumes this error, returning original [`CString`] which generated the
+    /// error.
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "cstring_into", since = "1.7.0")]
+    pub fn into_cstring(self) -> CString {
+        self.inner
+    }
+
+    /// Access the underlying UTF-8 error that was the cause of this error.
+    #[must_use]
+    #[stable(feature = "cstring_into", since = "1.7.0")]
+    pub fn utf8_error(&self) -> Utf8Error {
+        self.error
+    }
+
+    #[doc(hidden)]
+    #[unstable(feature = "cstr_internals", issue = "none")]
+    pub fn __source(&self) -> &Utf8Error {
+        &self.error
+    }
+}
+
+impl IntoStringError {
+    fn description(&self) -> &str {
+        "C string contained non-utf8 bytes"
+    }
+}
+
+#[stable(feature = "cstring_into", since = "1.7.0")]
+impl fmt::Display for IntoStringError {
+    #[allow(deprecated, deprecated_in_future)]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.description().fmt(f)
+    }
+}
+
+#[stable(feature = "cstr_borrow", since = "1.3.0")]
+impl ToOwned for CStr {
+    type Owned = CString;
+
+    fn to_owned(&self) -> CString {
+        CString { inner: self.to_bytes_with_nul().into() }
+    }
+
+    fn clone_into(&self, target: &mut CString) {
+        let mut b = into_vec(mem::take(&mut target.inner));
+        self.to_bytes_with_nul().clone_into(&mut b);
+        target.inner = b.into_boxed_slice();
+    }
+}
+
+#[stable(feature = "cstring_asref", since = "1.7.0")]
+impl From<&CStr> for CString {
+    fn from(s: &CStr) -> CString {
+        s.to_owned()
+    }
+}
+
+#[stable(feature = "cstring_asref", since = "1.7.0")]
+impl ops::Index<ops::RangeFull> for CString {
+    type Output = CStr;
+
+    #[inline]
+    fn index(&self, _index: ops::RangeFull) -> &CStr {
+        self
+    }
+}
+
+#[stable(feature = "cstring_asref", since = "1.7.0")]
+impl AsRef<CStr> for CString {
+    #[inline]
+    fn as_ref(&self) -> &CStr {
+        self
+    }
+}
+
+#[cfg(bootstrap)]
+#[doc(hidden)]
+#[unstable(feature = "cstr_internals", issue = "none")]
+pub trait CStrExt {
+    /// Converts a `CStr` into a <code>[Cow]<[str]></code>.
+    ///
+    /// If the contents of the `CStr` are valid UTF-8 data, this
+    /// function will return a <code>[Cow]::[Borrowed]\(&[str])</code>
+    /// with the corresponding <code>&[str]</code> slice. Otherwise, it will
+    /// replace any invalid UTF-8 sequences with
+    /// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD] and return a
+    /// <code>[Cow]::[Owned]\(&[str])</code> with the result.
+    ///
+    /// [str]: prim@str "str"
+    /// [Borrowed]: Cow::Borrowed
+    /// [Owned]: Cow::Owned
+    /// [U+FFFD]: crate::char::REPLACEMENT_CHARACTER "std::char::REPLACEMENT_CHARACTER"
+    ///
+    /// # Examples
+    ///
+    /// Calling `to_string_lossy` on a `CStr` containing valid UTF-8:
+    ///
+    /// ```
+    /// use std::borrow::Cow;
+    /// use std::ffi::CStr;
+    ///
+    /// let cstr = CStr::from_bytes_with_nul(b"Hello World\0")
+    ///                  .expect("CStr::from_bytes_with_nul failed");
+    /// assert_eq!(cstr.to_string_lossy(), Cow::Borrowed("Hello World"));
+    /// ```
+    ///
+    /// Calling `to_string_lossy` on a `CStr` containing invalid UTF-8:
+    ///
+    /// ```
+    /// use std::borrow::Cow;
+    /// use std::ffi::CStr;
+    ///
+    /// let cstr = CStr::from_bytes_with_nul(b"Hello \xF0\x90\x80World\0")
+    ///                  .expect("CStr::from_bytes_with_nul failed");
+    /// assert_eq!(
+    ///     cstr.to_string_lossy(),
+    ///     Cow::Owned(String::from("Hello �World")) as Cow<'_, str>
+    /// );
+    /// ```
+    #[must_use = "this returns the result of the operation, \
+                  without modifying the original"]
+    #[stable(feature = "cstr_to_str", since = "1.4.0")]
+    fn to_string_lossy(&self) -> Cow<'_, str>;
+
+    /// Converts a <code>[Box]<[CStr]></code> into a [`CString`] without copying or allocating.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed");
+    /// let boxed = c_string.into_boxed_c_str();
+    /// assert_eq!(boxed.into_c_string(), CString::new("foo").expect("CString::new failed"));
+    /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "into_boxed_c_str", since = "1.20.0")]
+    fn into_c_string(self: Box<Self>) -> CString;
+}
+
+#[cfg(bootstrap)]
+#[unstable(feature = "cstr_internals", issue = "none")]
+impl CStrExt for CStr {
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        String::from_utf8_lossy(self.to_bytes())
+    }
+
+    fn into_c_string(self: Box<Self>) -> CString {
+        CString::from(self)
+    }
+}
+
+#[cfg(not(bootstrap))]
+#[cfg(not(test))]
+impl CStr {
+    /// Converts a `CStr` into a <code>[Cow]<[str]></code>.
+    ///
+    /// If the contents of the `CStr` are valid UTF-8 data, this
+    /// function will return a <code>[Cow]::[Borrowed]\(&[str])</code>
+    /// with the corresponding <code>&[str]</code> slice. Otherwise, it will
+    /// replace any invalid UTF-8 sequences with
+    /// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD] and return a
+    /// <code>[Cow]::[Owned]\(&[str])</code> with the result.
+    ///
+    /// [str]: prim@str "str"
+    /// [Borrowed]: Cow::Borrowed
+    /// [Owned]: Cow::Owned
+    /// [U+FFFD]: core::char::REPLACEMENT_CHARACTER "std::char::REPLACEMENT_CHARACTER"
+    ///
+    /// # Examples
+    ///
+    /// Calling `to_string_lossy` on a `CStr` containing valid UTF-8:
+    ///
+    /// ```
+    /// use std::borrow::Cow;
+    /// use std::ffi::CStr;
+    ///
+    /// let cstr = CStr::from_bytes_with_nul(b"Hello World\0")
+    ///                  .expect("CStr::from_bytes_with_nul failed");
+    /// assert_eq!(cstr.to_string_lossy(), Cow::Borrowed("Hello World"));
+    /// ```
+    ///
+    /// Calling `to_string_lossy` on a `CStr` containing invalid UTF-8:
+    ///
+    /// ```
+    /// use std::borrow::Cow;
+    /// use std::ffi::CStr;
+    ///
+    /// let cstr = CStr::from_bytes_with_nul(b"Hello \xF0\x90\x80World\0")
+    ///                  .expect("CStr::from_bytes_with_nul failed");
+    /// assert_eq!(
+    ///     cstr.to_string_lossy(),
+    ///     Cow::Owned(String::from("Hello �World")) as Cow<'_, str>
+    /// );
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "this returns the result of the operation, \
+                  without modifying the original"]
+    #[stable(feature = "cstr_to_str", since = "1.4.0")]
+    pub fn to_string_lossy(&self) -> Cow<'_, str> {
+        String::from_utf8_lossy(self.to_bytes())
+    }
+
+    /// Converts a <code>[Box]<[CStr]></code> into a [`CString`] without copying or allocating.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ffi::CString;
+    ///
+    /// let c_string = CString::new(b"foo".to_vec()).expect("CString::new failed");
+    /// let boxed = c_string.into_boxed_c_str();
+    /// assert_eq!(boxed.into_c_string(), CString::new("foo").expect("CString::new failed"));
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "into_boxed_c_str", since = "1.20.0")]
+    pub fn into_c_string(self: Box<Self>) -> CString {
+        CString::from(self)
+    }
+}
diff --git a/rust/alloc/ffi/mod.rs b/rust/alloc/ffi/mod.rs
new file mode 100644
index 000000000000..56d429785339
--- /dev/null
+++ b/rust/alloc/ffi/mod.rs
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! Utilities related to FFI bindings.
+//!
+//! This module provides utilities to handle data across non-Rust
+//! interfaces, like other programming languages and the underlying
+//! operating system. It is mainly of use for FFI (Foreign Function
+//! Interface) bindings and code that needs to exchange C-like strings
+//! with other languages.
+//!
+//! # Overview
+//!
+//! Rust represents owned strings with the [`String`] type, and
+//! borrowed slices of strings with the [`str`] primitive. Both are
+//! always in UTF-8 encoding, and may contain nul bytes in the middle,
+//! i.e., if you look at the bytes that make up the string, there may
+//! be a `\0` among them. Both `String` and `str` store their length
+//! explicitly; there are no nul terminators at the end of strings
+//! like in C.
+//!
+//! C strings are different from Rust strings:
+//!
+//! * **Encodings** - Rust strings are UTF-8, but C strings may use
+//! other encodings. If you are using a string from C, you should
+//! check its encoding explicitly, rather than just assuming that it
+//! is UTF-8 like you can do in Rust.
+//!
+//! * **Character size** - C strings may use `char` or `wchar_t`-sized
+//! characters; please **note** that C's `char` is different from Rust's.
+//! The C standard leaves the actual sizes of those types open to
+//! interpretation, but defines different APIs for strings made up of
+//! each character type. Rust strings are always UTF-8, so different
+//! Unicode characters will be encoded in a variable number of bytes
+//! each. The Rust type [`char`] represents a '[Unicode scalar
+//! value]', which is similar to, but not the same as, a '[Unicode
+//! code point]'.
+//!
+//! * **Nul terminators and implicit string lengths** - Often, C
+//! strings are nul-terminated, i.e., they have a `\0` character at the
+//! end. The length of a string buffer is not stored, but has to be
+//! calculated; to compute the length of a string, C code must
+//! manually call a function like `strlen()` for `char`-based strings,
+//! or `wcslen()` for `wchar_t`-based ones. Those functions return
+//! the number of characters in the string excluding the nul
+//! terminator, so the buffer length is really `len+1` characters.
+//! Rust strings don't have a nul terminator; their length is always
+//! stored and does not need to be calculated. While in Rust
+//! accessing a string's length is an *O*(1) operation (because the
+//! length is stored); in C it is an *O*(*n*) operation because the
+//! length needs to be computed by scanning the string for the nul
+//! terminator.
+//!
+//! * **Internal nul characters** - When C strings have a nul
+//! terminator character, this usually means that they cannot have nul
+//! characters in the middle — a nul character would essentially
+//! truncate the string. Rust strings *can* have nul characters in
+//! the middle, because nul does not have to mark the end of the
+//! string in Rust.
+//!
+//! # Representations of non-Rust strings
+//!
+//! [`CString`] and [`CStr`] are useful when you need to transfer
+//! UTF-8 strings to and from languages with a C ABI, like Python.
+//!
+//! * **From Rust to C:** [`CString`] represents an owned, C-friendly
+//! string: it is nul-terminated, and has no internal nul characters.
+//! Rust code can create a [`CString`] out of a normal string (provided
+//! that the string doesn't have nul characters in the middle), and
+//! then use a variety of methods to obtain a raw <code>\*mut [u8]</code> that can
+//! then be passed as an argument to functions which use the C
+//! conventions for strings.
+//!
+//! * **From C to Rust:** [`CStr`] represents a borrowed C string; it
+//! is what you would use to wrap a raw <code>\*const [u8]</code> that you got from
+//! a C function. A [`CStr`] is guaranteed to be a nul-terminated array
+//! of bytes. Once you have a [`CStr`], you can convert it to a Rust
+//! <code>&[str]</code> if it's valid UTF-8, or lossily convert it by adding
+//! replacement characters.
+//!
+//! [`String`]: crate::string::String
+//! [`CStr`]: core::ffi::CStr
+
+#![unstable(feature = "alloc_ffi", issue = "94079")]
+
+#[cfg(bootstrap)]
+#[unstable(feature = "cstr_internals", issue = "none")]
+pub use self::c_str::CStrExt;
+#[unstable(feature = "alloc_c_string", issue = "94079")]
+pub use self::c_str::FromVecWithNulError;
+#[unstable(feature = "alloc_c_string", issue = "94079")]
+pub use self::c_str::{CString, IntoStringError, NulError};
+
+mod c_str;
diff --git a/rust/alloc/fmt.rs b/rust/alloc/fmt.rs
new file mode 100644
index 000000000000..b9c4d2926d23
--- /dev/null
+++ b/rust/alloc/fmt.rs
@@ -0,0 +1,614 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! Utilities for formatting and printing `String`s.
+//!
+//! This module contains the runtime support for the [`format!`] syntax extension.
+//! This macro is implemented in the compiler to emit calls to this module in
+//! order to format arguments at runtime into strings.
+//!
+//! # Usage
+//!
+//! The [`format!`] macro is intended to be familiar to those coming from C's
+//! `printf`/`fprintf` functions or Python's `str.format` function.
+//!
+//! Some examples of the [`format!`] extension are:
+//!
+//! ```
+//! format!("Hello");                 // => "Hello"
+//! format!("Hello, {}!", "world");   // => "Hello, world!"
+//! format!("The number is {}", 1);   // => "The number is 1"
+//! format!("{:?}", (3, 4));          // => "(3, 4)"
+//! format!("{value}", value=4);      // => "4"
+//! let people = "Rustaceans";
+//! format!("Hello {people}!");       // => "Hello Rustaceans!"
+//! format!("{} {}", 1, 2);           // => "1 2"
+//! format!("{:04}", 42);             // => "0042" with leading zeros
+//! format!("{:#?}", (100, 200));     // => "(
+//!                                   //       100,
+//!                                   //       200,
+//!                                   //     )"
+//! ```
+//!
+//! From these, you can see that the first argument is a format string. It is
+//! required by the compiler for this to be a string literal; it cannot be a
+//! variable passed in (in order to perform validity checking). The compiler
+//! will then parse the format string and determine if the list of arguments
+//! provided is suitable to pass to this format string.
+//!
+//! To convert a single value to a string, use the [`to_string`] method. This
+//! will use the [`Display`] formatting trait.
+//!
+//! ## Positional parameters
+//!
+//! Each formatting argument is allowed to specify which value argument it's
+//! referencing, and if omitted it is assumed to be "the next argument". For
+//! example, the format string `{} {} {}` would take three parameters, and they
+//! would be formatted in the same order as they're given. The format string
+//! `{2} {1} {0}`, however, would format arguments in reverse order.
+//!
+//! Things can get a little tricky once you start intermingling the two types of
+//! positional specifiers. The "next argument" specifier can be thought of as an
+//! iterator over the argument. Each time a "next argument" specifier is seen,
+//! the iterator advances. This leads to behavior like this:
+//!
+//! ```
+//! format!("{1} {} {0} {}", 1, 2); // => "2 1 1 2"
+//! ```
+//!
+//! The internal iterator over the argument has not been advanced by the time
+//! the first `{}` is seen, so it prints the first argument. Then upon reaching
+//! the second `{}`, the iterator has advanced forward to the second argument.
+//! Essentially, parameters that explicitly name their argument do not affect
+//! parameters that do not name an argument in terms of positional specifiers.
+//!
+//! A format string is required to use all of its arguments, otherwise it is a
+//! compile-time error. You may refer to the same argument more than once in the
+//! format string.
+//!
+//! ## Named parameters
+//!
+//! Rust itself does not have a Python-like equivalent of named parameters to a
+//! function, but the [`format!`] macro is a syntax extension that allows it to
+//! leverage named parameters. Named parameters are listed at the end of the
+//! argument list and have the syntax:
+//!
+//! ```text
+//! identifier '=' expression
+//! ```
+//!
+//! For example, the following [`format!`] expressions all use named arguments:
+//!
+//! ```
+//! format!("{argument}", argument = "test");   // => "test"
+//! format!("{name} {}", 1, name = 2);          // => "2 1"
+//! format!("{a} {c} {b}", a="a", b='b', c=3);  // => "a 3 b"
+//! ```
+//!
+//! If a named parameter does not appear in the argument list, `format!` will
+//! reference a variable with that name in the current scope.
+//!
+//! ```
+//! let argument = 2 + 2;
+//! format!("{argument}");   // => "4"
+//!
+//! fn make_string(a: u32, b: &str) -> String {
+//!     format!("{b} {a}")
+//! }
+//! make_string(927, "label"); // => "label 927"
+//! ```
+//!
+//! It is not valid to put positional parameters (those without names) after
+//! arguments that have names. Like with positional parameters, it is not
+//! valid to provide named parameters that are unused by the format string.
+//!
+//! # Formatting Parameters
+//!
+//! Each argument being formatted can be transformed by a number of formatting
+//! parameters (corresponding to `format_spec` in [the syntax](#syntax)). These
+//! parameters affect the string representation of what's being formatted.
+//!
+//! ## Width
+//!
+//! ```
+//! // All of these print "Hello x    !"
+//! println!("Hello {:5}!", "x");
+//! println!("Hello {:1$}!", "x", 5);
+//! println!("Hello {1:0$}!", 5, "x");
+//! println!("Hello {:width$}!", "x", width = 5);
+//! let width = 5;
+//! println!("Hello {:width$}!", "x");
+//! ```
+//!
+//! This is a parameter for the "minimum width" that the format should take up.
+//! If the value's string does not fill up this many characters, then the
+//! padding specified by fill/alignment will be used to take up the required
+//! space (see below).
+//!
+//! The value for the width can also be provided as a [`usize`] in the list of
+//! parameters by adding a postfix `$`, indicating that the second argument is
+//! a [`usize`] specifying the width.
+//!
+//! Referring to an argument with the dollar syntax does not affect the "next
+//! argument" counter, so it's usually a good idea to refer to arguments by
+//! position, or use named arguments.
+//!
+//! ## Fill/Alignment
+//!
+//! ```
+//! assert_eq!(format!("Hello {:<5}!", "x"),  "Hello x    !");
+//! assert_eq!(format!("Hello {:-<5}!", "x"), "Hello x----!");
+//! assert_eq!(format!("Hello {:^5}!", "x"),  "Hello   x  !");
+//! assert_eq!(format!("Hello {:>5}!", "x"),  "Hello     x!");
+//! ```
+//!
+//! The optional fill character and alignment is provided normally in conjunction with the
+//! [`width`](#width) parameter. It must be defined before `width`, right after the `:`.
+//! This indicates that if the value being formatted is smaller than
+//! `width` some extra characters will be printed around it.
+//! Filling comes in the following variants for different alignments:
+//!
+//! * `[fill]<` - the argument is left-aligned in `width` columns
+//! * `[fill]^` - the argument is center-aligned in `width` columns
+//! * `[fill]>` - the argument is right-aligned in `width` columns
+//!
+//! The default [fill/alignment](#fillalignment) for non-numerics is a space and
+//! left-aligned. The
+//! default for numeric formatters is also a space character but with right-alignment. If
+//! the `0` flag (see below) is specified for numerics, then the implicit fill character is
+//! `0`.
+//!
+//! Note that alignment might not be implemented by some types. In particular, it
+//! is not generally implemented for the `Debug` trait.  A good way to ensure
+//! padding is applied is to format your input, then pad this resulting string
+//! to obtain your output:
+//!
+//! ```
+//! println!("Hello {:^15}!", format!("{:?}", Some("hi"))); // => "Hello   Some("hi")   !"
+//! ```
+//!
+//! ## Sign/`#`/`0`
+//!
+//! ```
+//! assert_eq!(format!("Hello {:+}!", 5), "Hello +5!");
+//! assert_eq!(format!("{:#x}!", 27), "0x1b!");
+//! assert_eq!(format!("Hello {:05}!", 5),  "Hello 00005!");
+//! assert_eq!(format!("Hello {:05}!", -5), "Hello -0005!");
+//! assert_eq!(format!("{:#010x}!", 27), "0x0000001b!");
+//! ```
+//!
+//! These are all flags altering the behavior of the formatter.
+//!
+//! * `+` - This is intended for numeric types and indicates that the sign
+//!         should always be printed. Positive signs are never printed by
+//!         default, and the negative sign is only printed by default for signed values.
+//!         This flag indicates that the correct sign (`+` or `-`) should always be printed.
+//! * `-` - Currently not used
+//! * `#` - This flag indicates that the "alternate" form of printing should
+//!         be used. The alternate forms are:
+//!     * `#?` - pretty-print the [`Debug`] formatting (adds linebreaks and indentation)
+//!     * `#x` - precedes the argument with a `0x`
+//!     * `#X` - precedes the argument with a `0x`
+//!     * `#b` - precedes the argument with a `0b`
+//!     * `#o` - precedes the argument with a `0o`
+//! * `0` - This is used to indicate for integer formats that the padding to `width` should
+//!         both be done with a `0` character as well as be sign-aware. A format
+//!         like `{:08}` would yield `00000001` for the integer `1`, while the
+//!         same format would yield `-0000001` for the integer `-1`. Notice that
+//!         the negative version has one fewer zero than the positive version.
+//!         Note that padding zeros are always placed after the sign (if any)
+//!         and before the digits. When used together with the `#` flag, a similar
+//!         rule applies: padding zeros are inserted after the prefix but before
+//!         the digits. The prefix is included in the total width.
+//!
+//! ## Precision
+//!
+//! For non-numeric types, this can be considered a "maximum width". If the resulting string is
+//! longer than this width, then it is truncated down to this many characters and that truncated
+//! value is emitted with proper `fill`, `alignment` and `width` if those parameters are set.
+//!
+//! For integral types, this is ignored.
+//!
+//! For floating-point types, this indicates how many digits after the decimal point should be
+//! printed.
+//!
+//! There are three possible ways to specify the desired `precision`:
+//!
+//! 1. An integer `.N`:
+//!
+//!    the integer `N` itself is the precision.
+//!
+//! 2. An integer or name followed by dollar sign `.N$`:
+//!
+//!    use format *argument* `N` (which must be a `usize`) as the precision.
+//!
+//! 3. An asterisk `.*`:
+//!
+//!    `.*` means that this `{...}` is associated with *two* format inputs rather than one:
+//!    - If a format string in the fashion of `{:<spec>.*}` is used, then the first input holds
+//!      the `usize` precision, and the second holds the value to print.
+//!    - If a format string in the fashion of `{<arg>:<spec>.*}` is used, then the `<arg>` part
+//!      refers to the value to print, and the `precision` is taken like it was specified with an
+//!      omitted positional parameter (`{}` instead of `{<arg>:}`).
+//!
+//! For example, the following calls all print the same thing `Hello x is 0.01000`:
+//!
+//! ```
+//! // Hello {arg 0 ("x")} is {arg 1 (0.01) with precision specified inline (5)}
+//! println!("Hello {0} is {1:.5}", "x", 0.01);
+//!
+//! // Hello {arg 1 ("x")} is {arg 2 (0.01) with precision specified in arg 0 (5)}
+//! println!("Hello {1} is {2:.0$}", 5, "x", 0.01);
+//!
+//! // Hello {arg 0 ("x")} is {arg 2 (0.01) with precision specified in arg 1 (5)}
+//! println!("Hello {0} is {2:.1$}", "x", 5, 0.01);
+//!
+//! // Hello {next arg -> arg 0 ("x")} is {second of next two args -> arg 2 (0.01) with precision
+//! //                          specified in first of next two args -> arg 1 (5)}
+//! println!("Hello {} is {:.*}",    "x", 5, 0.01);
+//!
+//! // Hello {arg 1 ("x")} is {arg 2 (0.01) with precision
+//! //                          specified in next arg -> arg 0 (5)}
+//! println!("Hello {1} is {2:.*}",  5, "x", 0.01);
+//!
+//! // Hello {next arg -> arg 0 ("x")} is {arg 2 (0.01) with precision
+//! //                          specified in next arg -> arg 1 (5)}
+//! println!("Hello {} is {2:.*}",   "x", 5, 0.01);
+//!
+//! // Hello {next arg -> arg 0 ("x")} is {arg "number" (0.01) with precision specified
+//! //                          in arg "prec" (5)}
+//! println!("Hello {} is {number:.prec$}", "x", prec = 5, number = 0.01);
+//! ```
+//!
+//! While these:
+//!
+//! ```
+//! println!("{}, `{name:.*}` has 3 fractional digits", "Hello", 3, name=1234.56);
+//! println!("{}, `{name:.*}` has 3 characters", "Hello", 3, name="1234.56");
+//! println!("{}, `{name:>8.*}` has 3 right-aligned characters", "Hello", 3, name="1234.56");
+//! ```
+//!
+//! print three significantly different things:
+//!
+//! ```text
+//! Hello, `1234.560` has 3 fractional digits
+//! Hello, `123` has 3 characters
+//! Hello, `     123` has 3 right-aligned characters
+//! ```
+//!
+//! ## Localization
+//!
+//! In some programming languages, the behavior of string formatting functions
+//! depends on the operating system's locale setting. The format functions
+//! provided by Rust's standard library do not have any concept of locale and
+//! will produce the same results on all systems regardless of user
+//! configuration.
+//!
+//! For example, the following code will always print `1.5` even if the system
+//! locale uses a decimal separator other than a dot.
+//!
+//! ```
+//! println!("The value is {}", 1.5);
+//! ```
+//!
+//! # Escaping
+//!
+//! The literal characters `{` and `}` may be included in a string by preceding
+//! them with the same character. For example, the `{` character is escaped with
+//! `{{` and the `}` character is escaped with `}}`.
+//!
+//! ```
+//! assert_eq!(format!("Hello {{}}"), "Hello {}");
+//! assert_eq!(format!("{{ Hello"), "{ Hello");
+//! ```
+//!
+//! # Syntax
+//!
+//! To summarize, here you can find the full grammar of format strings.
+//! The syntax for the formatting language used is drawn from other languages,
+//! so it should not be too alien. Arguments are formatted with Python-like
+//! syntax, meaning that arguments are surrounded by `{}` instead of the C-like
+//! `%`. The actual grammar for the formatting syntax is:
+//!
+//! ```text
+//! format_string := text [ maybe_format text ] *
+//! maybe_format := '{' '{' | '}' '}' | format
+//! format := '{' [ argument ] [ ':' format_spec ] [ ws ] * '}'
+//! argument := integer | identifier
+//!
+//! format_spec := [[fill]align][sign]['#']['0'][width]['.' precision]type
+//! fill := character
+//! align := '<' | '^' | '>'
+//! sign := '+' | '-'
+//! width := count
+//! precision := count | '*'
+//! type := '' | '?' | 'x?' | 'X?' | identifier
+//! count := parameter | integer
+//! parameter := argument '$'
+//! ```
+//! In the above grammar,
+//! - `text` must not contain any `'{'` or `'}'` characters,
+//! - `ws` is any character for which [`char::is_whitespace`] returns `true`, has no semantic
+//!   meaning and is completely optional,
+//! - `integer` is a decimal integer that may contain leading zeroes and
+//! - `identifier` is an `IDENTIFIER_OR_KEYWORD` (not an `IDENTIFIER`) as defined by the [Rust language reference](https://doc.rust-lang.org/reference/identifiers.html).
+//!
+//! # Formatting traits
+//!
+//! When requesting that an argument be formatted with a particular type, you
+//! are actually requesting that an argument ascribes to a particular trait.
+//! This allows multiple actual types to be formatted via `{:x}` (like [`i8`] as
+//! well as [`isize`]). The current mapping of types to traits is:
+//!
+//! * *nothing* ⇒ [`Display`]
+//! * `?` ⇒ [`Debug`]
+//! * `x?` ⇒ [`Debug`] with lower-case hexadecimal integers
+//! * `X?` ⇒ [`Debug`] with upper-case hexadecimal integers
+//! * `o` ⇒ [`Octal`]
+//! * `x` ⇒ [`LowerHex`]
+//! * `X` ⇒ [`UpperHex`]
+//! * `p` ⇒ [`Pointer`]
+//! * `b` ⇒ [`Binary`]
+//! * `e` ⇒ [`LowerExp`]
+//! * `E` ⇒ [`UpperExp`]
+//!
+//! What this means is that any type of argument which implements the
+//! [`fmt::Binary`][`Binary`] trait can then be formatted with `{:b}`. Implementations
+//! are provided for these traits for a number of primitive types by the
+//! standard library as well. If no format is specified (as in `{}` or `{:6}`),
+//! then the format trait used is the [`Display`] trait.
+//!
+//! When implementing a format trait for your own type, you will have to
+//! implement a method of the signature:
+//!
+//! ```
+//! # #![allow(dead_code)]
+//! # use std::fmt;
+//! # struct Foo; // our custom type
+//! # impl fmt::Display for Foo {
+//! fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+//! # write!(f, "testing, testing")
+//! # } }
+//! ```
+//!
+//! Your type will be passed as `self` by-reference, and then the function
+//! should emit output into the Formatter `f` which implements `fmt::Write`. It is up to each
+//! format trait implementation to correctly adhere to the requested formatting parameters.
+//! The values of these parameters can be accessed with methods of the
+//! [`Formatter`] struct. In order to help with this, the [`Formatter`] struct also
+//! provides some helper methods.
+//!
+//! Additionally, the return value of this function is [`fmt::Result`] which is a
+//! type alias of <code>[Result]<(), [std::fmt::Error]></code>. Formatting implementations
+//! should ensure that they propagate errors from the [`Formatter`] (e.g., when
+//! calling [`write!`]). However, they should never return errors spuriously. That
+//! is, a formatting implementation must and may only return an error if the
+//! passed-in [`Formatter`] returns an error. This is because, contrary to what
+//! the function signature might suggest, string formatting is an infallible
+//! operation. This function only returns a result because writing to the
+//! underlying stream might fail and it must provide a way to propagate the fact
+//! that an error has occurred back up the stack.
+//!
+//! An example of implementing the formatting traits would look
+//! like:
+//!
+//! ```
+//! use std::fmt;
+//!
+//! #[derive(Debug)]
+//! struct Vector2D {
+//!     x: isize,
+//!     y: isize,
+//! }
+//!
+//! impl fmt::Display for Vector2D {
+//!     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+//!         // The `f` value implements the `Write` trait, which is what the
+//!         // write! macro is expecting. Note that this formatting ignores the
+//!         // various flags provided to format strings.
+//!         write!(f, "({}, {})", self.x, self.y)
+//!     }
+//! }
+//!
+//! // Different traits allow different forms of output of a type. The meaning
+//! // of this format is to print the magnitude of a vector.
+//! impl fmt::Binary for Vector2D {
+//!     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+//!         let magnitude = (self.x * self.x + self.y * self.y) as f64;
+//!         let magnitude = magnitude.sqrt();
+//!
+//!         // Respect the formatting flags by using the helper method
+//!         // `pad_integral` on the Formatter object. See the method
+//!         // documentation for details, and the function `pad` can be used
+//!         // to pad strings.
+//!         let decimals = f.precision().unwrap_or(3);
+//!         let string = format!("{:.*}", decimals, magnitude);
+//!         f.pad_integral(true, "", &string)
+//!     }
+//! }
+//!
+//! fn main() {
+//!     let myvector = Vector2D { x: 3, y: 4 };
+//!
+//!     println!("{myvector}");       // => "(3, 4)"
+//!     println!("{myvector:?}");     // => "Vector2D {x: 3, y:4}"
+//!     println!("{myvector:10.3b}"); // => "     5.000"
+//! }
+//! ```
+//!
+//! ### `fmt::Display` vs `fmt::Debug`
+//!
+//! These two formatting traits have distinct purposes:
+//!
+//! - [`fmt::Display`][`Display`] implementations assert that the type can be faithfully
+//!   represented as a UTF-8 string at all times. It is **not** expected that
+//!   all types implement the [`Display`] trait.
+//! - [`fmt::Debug`][`Debug`] implementations should be implemented for **all** public types.
+//!   Output will typically represent the internal state as faithfully as possible.
+//!   The purpose of the [`Debug`] trait is to facilitate debugging Rust code. In
+//!   most cases, using `#[derive(Debug)]` is sufficient and recommended.
+//!
+//! Some examples of the output from both traits:
+//!
+//! ```
+//! assert_eq!(format!("{} {:?}", 3, 4), "3 4");
+//! assert_eq!(format!("{} {:?}", 'a', 'b'), "a 'b'");
+//! assert_eq!(format!("{} {:?}", "foo\n", "bar\n"), "foo\n \"bar\\n\"");
+//! ```
+//!
+//! # Related macros
+//!
+//! There are a number of related macros in the [`format!`] family. The ones that
+//! are currently implemented are:
+//!
+//! ```ignore (only-for-syntax-highlight)
+//! format!      // described above
+//! write!       // first argument is either a &mut io::Write or a &mut fmt::Write, the destination
+//! writeln!     // same as write but appends a newline
+//! print!       // the format string is printed to the standard output
+//! println!     // same as print but appends a newline
+//! eprint!      // the format string is printed to the standard error
+//! eprintln!    // same as eprint but appends a newline
+//! format_args! // described below.
+//! ```
+//!
+//! ### `write!`
+//!
+//! [`write!`] and [`writeln!`] are two macros which are used to emit the format string
+//! to a specified stream. This is used to prevent intermediate allocations of
+//! format strings and instead directly write the output. Under the hood, this
+//! function is actually invoking the [`write_fmt`] function defined on the
+//! [`std::io::Write`] and the [`std::fmt::Write`] trait. Example usage is:
+//!
+//! ```
+//! # #![allow(unused_must_use)]
+//! use std::io::Write;
+//! let mut w = Vec::new();
+//! write!(&mut w, "Hello {}!", "world");
+//! ```
+//!
+//! ### `print!`
+//!
+//! This and [`println!`] emit their output to stdout. Similarly to the [`write!`]
+//! macro, the goal of these macros is to avoid intermediate allocations when
+//! printing output. Example usage is:
+//!
+//! ```
+//! print!("Hello {}!", "world");
+//! println!("I have a newline {}", "character at the end");
+//! ```
+//! ### `eprint!`
+//!
+//! The [`eprint!`] and [`eprintln!`] macros are identical to
+//! [`print!`] and [`println!`], respectively, except they emit their
+//! output to stderr.
+//!
+//! ### `format_args!`
+//!
+//! [`format_args!`] is a curious macro used to safely pass around
+//! an opaque object describing the format string. This object
+//! does not require any heap allocations to create, and it only
+//! references information on the stack. Under the hood, all of
+//! the related macros are implemented in terms of this. First
+//! off, some example usage is:
+//!
+//! ```
+//! # #![allow(unused_must_use)]
+//! use std::fmt;
+//! use std::io::{self, Write};
+//!
+//! let mut some_writer = io::stdout();
+//! write!(&mut some_writer, "{}", format_args!("print with a {}", "macro"));
+//!
+//! fn my_fmt_fn(args: fmt::Arguments) {
+//!     write!(&mut io::stdout(), "{}", args);
+//! }
+//! my_fmt_fn(format_args!(", or a {} too", "function"));
+//! ```
+//!
+//! The result of the [`format_args!`] macro is a value of type [`fmt::Arguments`].
+//! This structure can then be passed to the [`write`] and [`format`] functions
+//! inside this module in order to process the format string.
+//! The goal of this macro is to even further prevent intermediate allocations
+//! when dealing with formatting strings.
+//!
+//! For example, a logging library could use the standard formatting syntax, but
+//! it would internally pass around this structure until it has been determined
+//! where output should go to.
+//!
+//! [`fmt::Result`]: Result "fmt::Result"
+//! [Result]: core::result::Result "std::result::Result"
+//! [std::fmt::Error]: Error "fmt::Error"
+//! [`write`]: write() "fmt::write"
+//! [`to_string`]: crate::string::ToString::to_string "ToString::to_string"
+//! [`write_fmt`]: ../../std/io/trait.Write.html#method.write_fmt
+//! [`std::io::Write`]: ../../std/io/trait.Write.html
+//! [`std::fmt::Write`]: ../../std/fmt/trait.Write.html
+//! [`print!`]: ../../std/macro.print.html "print!"
+//! [`println!`]: ../../std/macro.println.html "println!"
+//! [`eprint!`]: ../../std/macro.eprint.html "eprint!"
+//! [`eprintln!`]: ../../std/macro.eprintln.html "eprintln!"
+//! [`format_args!`]: ../../std/macro.format_args.html "format_args!"
+//! [`fmt::Arguments`]: Arguments "fmt::Arguments"
+//! [`format`]: format() "fmt::format"
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[unstable(feature = "fmt_internals", issue = "none")]
+pub use core::fmt::rt;
+#[stable(feature = "fmt_flags_align", since = "1.28.0")]
+pub use core::fmt::Alignment;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::Error;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{write, ArgumentV1, Arguments};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{Binary, Octal};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{Debug, Display};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{DebugList, DebugMap, DebugSet, DebugStruct, DebugTuple};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{Formatter, Result, Write};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{LowerExp, UpperExp};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::fmt::{LowerHex, Pointer, UpperHex};
+
+#[cfg(not(no_global_oom_handling))]
+use crate::string;
+
+/// The `format` function takes an [`Arguments`] struct and returns the resulting
+/// formatted string.
+///
+/// The [`Arguments`] instance can be created with the [`format_args!`] macro.
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// use std::fmt;
+///
+/// let s = fmt::format(format_args!("Hello, {}!", "world"));
+/// assert_eq!(s, "Hello, world!");
+/// ```
+///
+/// Please note that using [`format!`] might be preferable.
+/// Example:
+///
+/// ```
+/// let s = format!("Hello, {}!", "world");
+/// assert_eq!(s, "Hello, world!");
+/// ```
+///
+/// [`format_args!`]: core::format_args
+/// [`format!`]: crate::format
+#[cfg(not(no_global_oom_handling))]
+#[must_use]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn format(args: Arguments<'_>) -> string::String {
+    let capacity = args.estimated_capacity();
+    let mut output = string::String::with_capacity(capacity);
+    output.write_fmt(args).expect("a formatting trait implementation returned an error");
+    output
+}
diff --git a/rust/alloc/lib.rs b/rust/alloc/lib.rs
new file mode 100644
index 000000000000..03d2ce1df814
--- /dev/null
+++ b/rust/alloc/lib.rs
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! # The Rust core allocation and collections library
+//!
+//! This library provides smart pointers and collections for managing
+//! heap-allocated values.
+//!
+//! This library, like libcore, normally doesn’t need to be used directly
+//! since its contents are re-exported in the [`std` crate](../std/index.html).
+//! Crates that use the `#![no_std]` attribute however will typically
+//! not depend on `std`, so they’d use this crate instead.
+//!
+//! ## Boxed values
+//!
+//! The [`Box`] type is a smart pointer type. There can only be one owner of a
+//! [`Box`], and the owner can decide to mutate the contents, which live on the
+//! heap.
+//!
+//! This type can be sent among threads efficiently as the size of a `Box` value
+//! is the same as that of a pointer. Tree-like data structures are often built
+//! with boxes because each node often has only one owner, the parent.
+//!
+//! ## Reference counted pointers
+//!
+//! The [`Rc`] type is a non-threadsafe reference-counted pointer type intended
+//! for sharing memory within a thread. An [`Rc`] pointer wraps a type, `T`, and
+//! only allows access to `&T`, a shared reference.
+//!
+//! This type is useful when inherited mutability (such as using [`Box`]) is too
+//! constraining for an application, and is often paired with the [`Cell`] or
+//! [`RefCell`] types in order to allow mutation.
+//!
+//! ## Atomically reference counted pointers
+//!
+//! The [`Arc`] type is the threadsafe equivalent of the [`Rc`] type. It
+//! provides all the same functionality of [`Rc`], except it requires that the
+//! contained type `T` is shareable. Additionally, [`Arc<T>`][`Arc`] is itself
+//! sendable while [`Rc<T>`][`Rc`] is not.
+//!
+//! This type allows for shared access to the contained data, and is often
+//! paired with synchronization primitives such as mutexes to allow mutation of
+//! shared resources.
+//!
+//! ## Collections
+//!
+//! Implementations of the most common general purpose data structures are
+//! defined in this library. They are re-exported through the
+//! [standard collections library](../std/collections/index.html).
+//!
+//! ## Heap interfaces
+//!
+//! The [`alloc`](alloc/index.html) module defines the low-level interface to the
+//! default global allocator. It is not compatible with the libc allocator API.
+//!
+//! [`Arc`]: sync
+//! [`Box`]: boxed
+//! [`Cell`]: core::cell
+//! [`Rc`]: rc
+//! [`RefCell`]: core::cell
+
+// To run liballoc tests without x.py without ending up with two copies of liballoc, Miri needs to be
+// able to "empty" this crate. See <https://github.com/rust-lang/miri-test-libstd/issues/4>.
+// rustc itself never sets the feature, so this line has no affect there.
+#![cfg(any(not(feature = "miri-test-libstd"), test, doctest))]
+#![allow(unused_attributes)]
+#![stable(feature = "alloc", since = "1.36.0")]
+#![doc(
+    html_playground_url = "https://play.rust-lang.org/",
+    issue_tracker_base_url = "https://github.com/rust-lang/rust/issues/",
+    test(no_crate_inject, attr(allow(unused_variables), deny(warnings)))
+)]
+#![doc(cfg_hide(
+    not(test),
+    not(any(test, bootstrap)),
+    any(not(feature = "miri-test-libstd"), test, doctest),
+    no_global_oom_handling,
+    not(no_global_oom_handling),
+    target_has_atomic = "ptr"
+))]
+#![no_std]
+#![needs_allocator]
+//
+// Lints:
+#![deny(unsafe_op_in_unsafe_fn)]
+#![warn(deprecated_in_future)]
+#![warn(missing_debug_implementations)]
+#![warn(missing_docs)]
+#![allow(explicit_outlives_requirements)]
+//
+// Library features:
+#![cfg_attr(not(no_global_oom_handling), feature(alloc_c_string))]
+#![feature(alloc_layout_extra)]
+#![feature(allocator_api)]
+#![feature(array_chunks)]
+#![feature(array_methods)]
+#![feature(array_windows)]
+#![feature(assert_matches)]
+#![feature(async_iterator)]
+#![feature(coerce_unsized)]
+#![cfg_attr(not(no_global_oom_handling), feature(const_alloc_error))]
+#![feature(const_box)]
+#![cfg_attr(not(no_global_oom_handling), feature(const_btree_new))]
+#![feature(const_cow_is_borrowed)]
+#![feature(const_convert)]
+#![feature(const_size_of_val)]
+#![feature(const_align_of_val)]
+#![feature(const_ptr_read)]
+#![feature(const_maybe_uninit_write)]
+#![feature(const_maybe_uninit_as_mut_ptr)]
+#![feature(const_refs_to_cell)]
+#![feature(core_c_str)]
+#![feature(core_intrinsics)]
+#![feature(core_ffi_c)]
+#![feature(const_eval_select)]
+#![feature(const_pin)]
+#![feature(cstr_from_bytes_until_nul)]
+#![feature(dispatch_from_dyn)]
+#![feature(exact_size_is_empty)]
+#![feature(extend_one)]
+#![feature(fmt_internals)]
+#![feature(fn_traits)]
+#![feature(hasher_prefixfree_extras)]
+#![feature(inplace_iteration)]
+#![feature(iter_advance_by)]
+#![feature(layout_for_ptr)]
+#![feature(maybe_uninit_slice)]
+#![cfg_attr(test, feature(new_uninit))]
+#![feature(nonnull_slice_from_raw_parts)]
+#![feature(pattern)]
+#![feature(ptr_internals)]
+#![feature(ptr_metadata)]
+#![feature(ptr_sub_ptr)]
+#![feature(receiver_trait)]
+#![feature(set_ptr_value)]
+#![feature(slice_group_by)]
+#![feature(slice_ptr_get)]
+#![feature(slice_ptr_len)]
+#![feature(slice_range)]
+#![feature(str_internals)]
+#![feature(strict_provenance)]
+#![feature(trusted_len)]
+#![feature(trusted_random_access)]
+#![feature(try_trait_v2)]
+#![feature(unchecked_math)]
+#![feature(unicode_internals)]
+#![feature(unsize)]
+//
+// Language features:
+#![feature(allocator_internals)]
+#![feature(allow_internal_unstable)]
+#![feature(associated_type_bounds)]
+#![feature(box_syntax)]
+#![feature(cfg_sanitize)]
+#![feature(const_deref)]
+#![feature(const_mut_refs)]
+#![feature(const_ptr_write)]
+#![feature(const_precise_live_drops)]
+#![feature(const_trait_impl)]
+#![feature(const_try)]
+#![feature(dropck_eyepatch)]
+#![feature(exclusive_range_pattern)]
+#![feature(fundamental)]
+#![cfg_attr(not(test), feature(generator_trait))]
+#![feature(hashmap_internals)]
+#![feature(lang_items)]
+#![feature(let_else)]
+#![feature(min_specialization)]
+#![feature(negative_impls)]
+#![feature(never_type)]
+#![feature(nll)] // Not necessary, but here to test the `nll` feature.
+#![feature(rustc_allow_const_fn_unstable)]
+#![feature(rustc_attrs)]
+#![feature(slice_internals)]
+#![feature(staged_api)]
+#![cfg_attr(test, feature(test))]
+#![feature(unboxed_closures)]
+#![feature(unsized_fn_params)]
+#![feature(c_unwind)]
+//
+// Rustdoc features:
+#![feature(doc_cfg)]
+#![feature(doc_cfg_hide)]
+// Technically, this is a bug in rustdoc: rustdoc sees the documentation on `#[lang = slice_alloc]`
+// blocks is for `&[T]`, which also has documentation using this feature in `core`, and gets mad
+// that the feature-gate isn't enabled. Ideally, it wouldn't check for the feature gate for docs
+// from other crates, but since this can only appear for lang items, it doesn't seem worth fixing.
+#![feature(intra_doc_pointers)]
+
+// Allow testing this library
+#[cfg(test)]
+#[macro_use]
+extern crate std;
+#[cfg(test)]
+extern crate test;
+
+// Module with internal macros used by other modules (needs to be included before other modules).
+#[macro_use]
+mod macros;
+
+mod raw_vec;
+
+// Heaps provided for low-level allocation strategies
+
+pub mod alloc;
+
+// Primitive types using the heaps above
+
+// Need to conditionally define the mod from `boxed.rs` to avoid
+// duplicating the lang-items when building in test cfg; but also need
+// to allow code to have `use boxed::Box;` declarations.
+#[cfg(not(test))]
+pub mod boxed;
+#[cfg(test)]
+mod boxed {
+    pub use std::boxed::Box;
+}
+pub mod borrow;
+pub mod collections;
+#[cfg(not(no_global_oom_handling))]
+pub mod ffi;
+pub mod fmt;
+#[cfg(not(no_rc))]
+pub mod rc;
+pub mod slice;
+pub mod str;
+pub mod string;
+#[cfg(all(not(no_sync), target_has_atomic = "ptr"))]
+pub mod sync;
+#[cfg(all(not(no_global_oom_handling), target_has_atomic = "ptr"))]
+pub mod task;
+#[cfg(test)]
+mod tests;
+pub mod vec;
+
+#[doc(hidden)]
+#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
+pub mod __export {
+    pub use core::format_args;
+}
diff --git a/rust/alloc/macros.rs b/rust/alloc/macros.rs
new file mode 100644
index 000000000000..fa7bacfd5847
--- /dev/null
+++ b/rust/alloc/macros.rs
@@ -0,0 +1,128 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+/// Creates a [`Vec`] containing the arguments.
+///
+/// `vec!` allows `Vec`s to be defined with the same syntax as array expressions.
+/// There are two forms of this macro:
+///
+/// - Create a [`Vec`] containing a given list of elements:
+///
+/// ```
+/// let v = vec![1, 2, 3];
+/// assert_eq!(v[0], 1);
+/// assert_eq!(v[1], 2);
+/// assert_eq!(v[2], 3);
+/// ```
+///
+/// - Create a [`Vec`] from a given element and size:
+///
+/// ```
+/// let v = vec![1; 3];
+/// assert_eq!(v, [1, 1, 1]);
+/// ```
+///
+/// Note that unlike array expressions this syntax supports all elements
+/// which implement [`Clone`] and the number of elements doesn't have to be
+/// a constant.
+///
+/// This will use `clone` to duplicate an expression, so one should be careful
+/// using this with types having a nonstandard `Clone` implementation. For
+/// example, `vec![Rc::new(1); 5]` will create a vector of five references
+/// to the same boxed integer value, not five references pointing to independently
+/// boxed integers.
+///
+/// Also, note that `vec![expr; 0]` is allowed, and produces an empty vector.
+/// This will still evaluate `expr`, however, and immediately drop the resulting value, so
+/// be mindful of side effects.
+///
+/// [`Vec`]: crate::vec::Vec
+#[cfg(all(not(no_global_oom_handling), not(test)))]
+#[macro_export]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_diagnostic_item = "vec_macro"]
+#[allow_internal_unstable(box_syntax, liballoc_internals)]
+macro_rules! vec {
+    () => (
+        $crate::__rust_force_expr!($crate::vec::Vec::new())
+    );
+    ($elem:expr; $n:expr) => (
+        $crate::__rust_force_expr!($crate::vec::from_elem($elem, $n))
+    );
+    ($($x:expr),+ $(,)?) => (
+        $crate::__rust_force_expr!(<[_]>::into_vec(box [$($x),+]))
+    );
+}
+
+// HACK(japaric): with cfg(test) the inherent `[T]::into_vec` method, which is
+// required for this macro definition, is not available. Instead use the
+// `slice::into_vec`  function which is only available with cfg(test)
+// NB see the slice::hack module in slice.rs for more information
+#[cfg(all(not(no_global_oom_handling), test))]
+#[cfg_attr(not(bootstrap), allow(unused_macro_rules))]
+macro_rules! vec {
+    () => (
+        $crate::vec::Vec::new()
+    );
+    ($elem:expr; $n:expr) => (
+        $crate::vec::from_elem($elem, $n)
+    );
+    ($($x:expr),*) => (
+        $crate::slice::into_vec(box [$($x),*])
+    );
+    ($($x:expr,)*) => (vec![$($x),*])
+}
+
+/// Creates a `String` using interpolation of runtime expressions.
+///
+/// The first argument `format!` receives is a format string. This must be a string
+/// literal. The power of the formatting string is in the `{}`s contained.
+///
+/// Additional parameters passed to `format!` replace the `{}`s within the
+/// formatting string in the order given unless named or positional parameters
+/// are used; see [`std::fmt`] for more information.
+///
+/// A common use for `format!` is concatenation and interpolation of strings.
+/// The same convention is used with [`print!`] and [`write!`] macros,
+/// depending on the intended destination of the string.
+///
+/// To convert a single value to a string, use the [`to_string`] method. This
+/// will use the [`Display`] formatting trait.
+///
+/// [`std::fmt`]: ../std/fmt/index.html
+/// [`print!`]: ../std/macro.print.html
+/// [`write!`]: core::write
+/// [`to_string`]: crate::string::ToString
+/// [`Display`]: core::fmt::Display
+///
+/// # Panics
+///
+/// `format!` panics if a formatting trait implementation returns an error.
+/// This indicates an incorrect implementation
+/// since `fmt::Write for String` never returns an error itself.
+///
+/// # Examples
+///
+/// ```
+/// format!("test");
+/// format!("hello {}", "world!");
+/// format!("x = {}, y = {y}", 10, y = 30);
+/// ```
+#[macro_export]
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "format_macro")]
+macro_rules! format {
+    ($($arg:tt)*) => {{
+        let res = $crate::fmt::format($crate::__export::format_args!($($arg)*));
+        res
+    }}
+}
+
+/// Force AST node to an expression to improve diagnostics in pattern position.
+#[doc(hidden)]
+#[macro_export]
+#[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]
+macro_rules! __rust_force_expr {
+    ($e:expr) => {
+        $e
+    };
+}
diff --git a/rust/alloc/raw_vec.rs b/rust/alloc/raw_vec.rs
new file mode 100644
index 000000000000..59e353bfe5d3
--- /dev/null
+++ b/rust/alloc/raw_vec.rs
@@ -0,0 +1,567 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+#![unstable(feature = "raw_vec_internals", reason = "unstable const warnings", issue = "none")]
+
+use core::alloc::LayoutError;
+use core::cmp;
+use core::intrinsics;
+use core::mem::{self, ManuallyDrop, MaybeUninit};
+use core::ops::Drop;
+use core::ptr::{self, NonNull, Unique};
+use core::slice;
+
+#[cfg(not(no_global_oom_handling))]
+use crate::alloc::handle_alloc_error;
+use crate::alloc::{Allocator, Global, Layout};
+use crate::boxed::Box;
+use crate::collections::TryReserveError;
+use crate::collections::TryReserveErrorKind::*;
+
+#[cfg(test)]
+mod tests;
+
+enum AllocInit {
+    /// The contents of the new memory are uninitialized.
+    Uninitialized,
+    #[allow(dead_code)]
+    /// The new memory is guaranteed to be zeroed.
+    Zeroed,
+}
+
+/// A low-level utility for more ergonomically allocating, reallocating, and deallocating
+/// a buffer of memory on the heap without having to worry about all the corner cases
+/// involved. This type is excellent for building your own data structures like Vec and VecDeque.
+/// In particular:
+///
+/// * Produces `Unique::dangling()` on zero-sized types.
+/// * Produces `Unique::dangling()` on zero-length allocations.
+/// * Avoids freeing `Unique::dangling()`.
+/// * Catches all overflows in capacity computations (promotes them to "capacity overflow" panics).
+/// * Guards against 32-bit systems allocating more than isize::MAX bytes.
+/// * Guards against overflowing your length.
+/// * Calls `handle_alloc_error` for fallible allocations.
+/// * Contains a `ptr::Unique` and thus endows the user with all related benefits.
+/// * Uses the excess returned from the allocator to use the largest available capacity.
+///
+/// This type does not in anyway inspect the memory that it manages. When dropped it *will*
+/// free its memory, but it *won't* try to drop its contents. It is up to the user of `RawVec`
+/// to handle the actual things *stored* inside of a `RawVec`.
+///
+/// Note that the excess of a zero-sized types is always infinite, so `capacity()` always returns
+/// `usize::MAX`. This means that you need to be careful when round-tripping this type with a
+/// `Box<[T]>`, since `capacity()` won't yield the length.
+#[allow(missing_debug_implementations)]
+pub(crate) struct RawVec<T, A: Allocator = Global> {
+    ptr: Unique<T>,
+    cap: usize,
+    alloc: A,
+}
+
+impl<T> RawVec<T, Global> {
+    /// HACK(Centril): This exists because stable `const fn` can only call stable `const fn`, so
+    /// they cannot call `Self::new()`.
+    ///
+    /// If you change `RawVec<T>::new` or dependencies, please take care to not introduce anything
+    /// that would truly const-call something unstable.
+    pub const NEW: Self = Self::new();
+
+    /// Creates the biggest possible `RawVec` (on the system heap)
+    /// without allocating. If `T` has positive size, then this makes a
+    /// `RawVec` with capacity `0`. If `T` is zero-sized, then it makes a
+    /// `RawVec` with capacity `usize::MAX`. Useful for implementing
+    /// delayed allocation.
+    #[must_use]
+    pub const fn new() -> Self {
+        Self::new_in(Global)
+    }
+
+    /// Creates a `RawVec` (on the system heap) with exactly the
+    /// capacity and alignment requirements for a `[T; capacity]`. This is
+    /// equivalent to calling `RawVec::new` when `capacity` is `0` or `T` is
+    /// zero-sized. Note that if `T` is zero-sized this means you will
+    /// *not* get a `RawVec` with the requested capacity.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the requested capacity exceeds `isize::MAX` bytes.
+    ///
+    /// # Aborts
+    ///
+    /// Aborts on OOM.
+    #[cfg(not(any(no_global_oom_handling, test)))]
+    #[must_use]
+    #[inline]
+    pub fn with_capacity(capacity: usize) -> Self {
+        Self::with_capacity_in(capacity, Global)
+    }
+
+    /// Like `with_capacity`, but guarantees the buffer is zeroed.
+    #[cfg(not(any(no_global_oom_handling, test)))]
+    #[must_use]
+    #[inline]
+    pub fn with_capacity_zeroed(capacity: usize) -> Self {
+        Self::with_capacity_zeroed_in(capacity, Global)
+    }
+}
+
+impl<T, A: Allocator> RawVec<T, A> {
+    // Tiny Vecs are dumb. Skip to:
+    // - 8 if the element size is 1, because any heap allocators is likely
+    //   to round up a request of less than 8 bytes to at least 8 bytes.
+    // - 4 if elements are moderate-sized (<= 1 KiB).
+    // - 1 otherwise, to avoid wasting too much space for very short Vecs.
+    pub(crate) const MIN_NON_ZERO_CAP: usize = if mem::size_of::<T>() == 1 {
+        8
+    } else if mem::size_of::<T>() <= 1024 {
+        4
+    } else {
+        1
+    };
+
+    /// Like `new`, but parameterized over the choice of allocator for
+    /// the returned `RawVec`.
+    pub const fn new_in(alloc: A) -> Self {
+        // `cap: 0` means "unallocated". zero-sized types are ignored.
+        Self { ptr: Unique::dangling(), cap: 0, alloc }
+    }
+
+    /// Like `with_capacity`, but parameterized over the choice of
+    /// allocator for the returned `RawVec`.
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    pub fn with_capacity_in(capacity: usize, alloc: A) -> Self {
+        Self::allocate_in(capacity, AllocInit::Uninitialized, alloc)
+    }
+
+    /// Like `try_with_capacity`, but parameterized over the choice of
+    /// allocator for the returned `RawVec`.
+    #[inline]
+    pub fn try_with_capacity_in(capacity: usize, alloc: A) -> Result<Self, TryReserveError> {
+        Self::try_allocate_in(capacity, AllocInit::Uninitialized, alloc)
+    }
+
+    /// Like `with_capacity_zeroed`, but parameterized over the choice
+    /// of allocator for the returned `RawVec`.
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    pub fn with_capacity_zeroed_in(capacity: usize, alloc: A) -> Self {
+        Self::allocate_in(capacity, AllocInit::Zeroed, alloc)
+    }
+
+    /// Converts the entire buffer into `Box<[MaybeUninit<T>]>` with the specified `len`.
+    ///
+    /// Note that this will correctly reconstitute any `cap` changes
+    /// that may have been performed. (See description of type for details.)
+    ///
+    /// # Safety
+    ///
+    /// * `len` must be greater than or equal to the most recently requested capacity, and
+    /// * `len` must be less than or equal to `self.capacity()`.
+    ///
+    /// Note, that the requested capacity and `self.capacity()` could differ, as
+    /// an allocator could overallocate and return a greater memory block than requested.
+    pub unsafe fn into_box(self, len: usize) -> Box<[MaybeUninit<T>], A> {
+        // Sanity-check one half of the safety requirement (we cannot check the other half).
+        debug_assert!(
+            len <= self.capacity(),
+            "`len` must be smaller than or equal to `self.capacity()`"
+        );
+
+        let me = ManuallyDrop::new(self);
+        unsafe {
+            let slice = slice::from_raw_parts_mut(me.ptr() as *mut MaybeUninit<T>, len);
+            Box::from_raw_in(slice, ptr::read(&me.alloc))
+        }
+    }
+
+    #[cfg(not(no_global_oom_handling))]
+    fn allocate_in(capacity: usize, init: AllocInit, alloc: A) -> Self {
+        // Don't allocate here because `Drop` will not deallocate when `capacity` is 0.
+        if mem::size_of::<T>() == 0 || capacity == 0 {
+            Self::new_in(alloc)
+        } else {
+            // We avoid `unwrap_or_else` here because it bloats the amount of
+            // LLVM IR generated.
+            let layout = match Layout::array::<T>(capacity) {
+                Ok(layout) => layout,
+                Err(_) => capacity_overflow(),
+            };
+            match alloc_guard(layout.size()) {
+                Ok(_) => {}
+                Err(_) => capacity_overflow(),
+            }
+            let result = match init {
+                AllocInit::Uninitialized => alloc.allocate(layout),
+                AllocInit::Zeroed => alloc.allocate_zeroed(layout),
+            };
+            let ptr = match result {
+                Ok(ptr) => ptr,
+                Err(_) => handle_alloc_error(layout),
+            };
+
+            // Allocators currently return a `NonNull<[u8]>` whose length
+            // matches the size requested. If that ever changes, the capacity
+            // here should change to `ptr.len() / mem::size_of::<T>()`.
+            Self {
+                ptr: unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) },
+                cap: capacity,
+                alloc,
+            }
+        }
+    }
+
+    fn try_allocate_in(capacity: usize, init: AllocInit, alloc: A) -> Result<Self, TryReserveError> {
+        // Don't allocate here because `Drop` will not deallocate when `capacity` is 0.
+        if mem::size_of::<T>() == 0 || capacity == 0 {
+            return Ok(Self::new_in(alloc));
+        }
+
+        let layout = Layout::array::<T>(capacity).map_err(|_| CapacityOverflow)?;
+        alloc_guard(layout.size())?;
+        let result = match init {
+            AllocInit::Uninitialized => alloc.allocate(layout),
+            AllocInit::Zeroed => alloc.allocate_zeroed(layout),
+        };
+        let ptr = result.map_err(|_| AllocError { layout, non_exhaustive: () })?;
+
+        // Allocators currently return a `NonNull<[u8]>` whose length
+        // matches the size requested. If that ever changes, the capacity
+        // here should change to `ptr.len() / mem::size_of::<T>()`.
+        Ok(Self {
+            ptr: unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) },
+            cap: capacity,
+            alloc,
+        })
+    }
+
+    /// Reconstitutes a `RawVec` from a pointer, capacity, and allocator.
+    ///
+    /// # Safety
+    ///
+    /// The `ptr` must be allocated (via the given allocator `alloc`), and with the given
+    /// `capacity`.
+    /// The `capacity` cannot exceed `isize::MAX` for sized types. (only a concern on 32-bit
+    /// systems). ZST vectors may have a capacity up to `usize::MAX`.
+    /// If the `ptr` and `capacity` come from a `RawVec` created via `alloc`, then this is
+    /// guaranteed.
+    #[inline]
+    pub unsafe fn from_raw_parts_in(ptr: *mut T, capacity: usize, alloc: A) -> Self {
+        Self { ptr: unsafe { Unique::new_unchecked(ptr) }, cap: capacity, alloc }
+    }
+
+    /// Gets a raw pointer to the start of the allocation. Note that this is
+    /// `Unique::dangling()` if `capacity == 0` or `T` is zero-sized. In the former case, you must
+    /// be careful.
+    #[inline]
+    pub fn ptr(&self) -> *mut T {
+        self.ptr.as_ptr()
+    }
+
+    /// Gets the capacity of the allocation.
+    ///
+    /// This will always be `usize::MAX` if `T` is zero-sized.
+    #[inline(always)]
+    pub fn capacity(&self) -> usize {
+        if mem::size_of::<T>() == 0 { usize::MAX } else { self.cap }
+    }
+
+    /// Returns a shared reference to the allocator backing this `RawVec`.
+    pub fn allocator(&self) -> &A {
+        &self.alloc
+    }
+
+    fn current_memory(&self) -> Option<(NonNull<u8>, Layout)> {
+        if mem::size_of::<T>() == 0 || self.cap == 0 {
+            None
+        } else {
+            // We have an allocated chunk of memory, so we can bypass runtime
+            // checks to get our current layout.
+            unsafe {
+                let layout = Layout::array::<T>(self.cap).unwrap_unchecked();
+                Some((self.ptr.cast().into(), layout))
+            }
+        }
+    }
+
+    /// Ensures that the buffer contains at least enough space to hold `len +
+    /// additional` elements. If it doesn't already have enough capacity, will
+    /// reallocate enough space plus comfortable slack space to get amortized
+    /// *O*(1) behavior. Will limit this behavior if it would needlessly cause
+    /// itself to panic.
+    ///
+    /// If `len` exceeds `self.capacity()`, this may fail to actually allocate
+    /// the requested space. This is not really unsafe, but the unsafe
+    /// code *you* write that relies on the behavior of this function may break.
+    ///
+    /// This is ideal for implementing a bulk-push operation like `extend`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity exceeds `isize::MAX` bytes.
+    ///
+    /// # Aborts
+    ///
+    /// Aborts on OOM.
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    pub fn reserve(&mut self, len: usize, additional: usize) {
+        // Callers expect this function to be very cheap when there is already sufficient capacity.
+        // Therefore, we move all the resizing and error-handling logic from grow_amortized and
+        // handle_reserve behind a call, while making sure that this function is likely to be
+        // inlined as just a comparison and a call if the comparison fails.
+        #[cold]
+        fn do_reserve_and_handle<T, A: Allocator>(
+            slf: &mut RawVec<T, A>,
+            len: usize,
+            additional: usize,
+        ) {
+            handle_reserve(slf.grow_amortized(len, additional));
+        }
+
+        if self.needs_to_grow(len, additional) {
+            do_reserve_and_handle(self, len, additional);
+        }
+    }
+
+    /// A specialized version of `reserve()` used only by the hot and
+    /// oft-instantiated `Vec::push()`, which does its own capacity check.
+    #[cfg(not(no_global_oom_handling))]
+    #[inline(never)]
+    pub fn reserve_for_push(&mut self, len: usize) {
+        handle_reserve(self.grow_amortized(len, 1));
+    }
+
+    /// The same as `reserve`, but returns on errors instead of panicking or aborting.
+    pub fn try_reserve(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {
+        if self.needs_to_grow(len, additional) {
+            self.grow_amortized(len, additional)
+        } else {
+            Ok(())
+        }
+    }
+
+    /// The same as `reserve_for_push`, but returns on errors instead of panicking or aborting.
+    #[inline(never)]
+    pub fn try_reserve_for_push(&mut self, len: usize) -> Result<(), TryReserveError> {
+        self.grow_amortized(len, 1)
+    }
+
+    /// Ensures that the buffer contains at least enough space to hold `len +
+    /// additional` elements. If it doesn't already, will reallocate the
+    /// minimum possible amount of memory necessary. Generally this will be
+    /// exactly the amount of memory necessary, but in principle the allocator
+    /// is free to give back more than we asked for.
+    ///
+    /// If `len` exceeds `self.capacity()`, this may fail to actually allocate
+    /// the requested space. This is not really unsafe, but the unsafe code
+    /// *you* write that relies on the behavior of this function may break.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity exceeds `isize::MAX` bytes.
+    ///
+    /// # Aborts
+    ///
+    /// Aborts on OOM.
+    #[cfg(not(no_global_oom_handling))]
+    pub fn reserve_exact(&mut self, len: usize, additional: usize) {
+        handle_reserve(self.try_reserve_exact(len, additional));
+    }
+
+    /// The same as `reserve_exact`, but returns on errors instead of panicking or aborting.
+    pub fn try_reserve_exact(
+        &mut self,
+        len: usize,
+        additional: usize,
+    ) -> Result<(), TryReserveError> {
+        if self.needs_to_grow(len, additional) { self.grow_exact(len, additional) } else { Ok(()) }
+    }
+
+    /// Shrinks the buffer down to the specified capacity. If the given amount
+    /// is 0, actually completely deallocates.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the given amount is *larger* than the current capacity.
+    ///
+    /// # Aborts
+    ///
+    /// Aborts on OOM.
+    #[cfg(not(no_global_oom_handling))]
+    pub fn shrink_to_fit(&mut self, cap: usize) {
+        handle_reserve(self.shrink(cap));
+    }
+
+    /// Tries to shrink the buffer down to the specified capacity. If the given amount
+    /// is 0, actually completely deallocates.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the given amount is *larger* than the current capacity.
+    pub fn try_shrink_to_fit(&mut self, cap: usize) -> Result<(), TryReserveError> {
+        self.shrink(cap)
+    }
+}
+
+impl<T, A: Allocator> RawVec<T, A> {
+    /// Returns if the buffer needs to grow to fulfill the needed extra capacity.
+    /// Mainly used to make inlining reserve-calls possible without inlining `grow`.
+    fn needs_to_grow(&self, len: usize, additional: usize) -> bool {
+        additional > self.capacity().wrapping_sub(len)
+    }
+
+    fn set_ptr_and_cap(&mut self, ptr: NonNull<[u8]>, cap: usize) {
+        // Allocators currently return a `NonNull<[u8]>` whose length matches
+        // the size requested. If that ever changes, the capacity here should
+        // change to `ptr.len() / mem::size_of::<T>()`.
+        self.ptr = unsafe { Unique::new_unchecked(ptr.cast().as_ptr()) };
+        self.cap = cap;
+    }
+
+    // This method is usually instantiated many times. So we want it to be as
+    // small as possible, to improve compile times. But we also want as much of
+    // its contents to be statically computable as possible, to make the
+    // generated code run faster. Therefore, this method is carefully written
+    // so that all of the code that depends on `T` is within it, while as much
+    // of the code that doesn't depend on `T` as possible is in functions that
+    // are non-generic over `T`.
+    fn grow_amortized(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {
+        // This is ensured by the calling contexts.
+        debug_assert!(additional > 0);
+
+        if mem::size_of::<T>() == 0 {
+            // Since we return a capacity of `usize::MAX` when `elem_size` is
+            // 0, getting to here necessarily means the `RawVec` is overfull.
+            return Err(CapacityOverflow.into());
+        }
+
+        // Nothing we can really do about these checks, sadly.
+        let required_cap = len.checked_add(additional).ok_or(CapacityOverflow)?;
+
+        // This guarantees exponential growth. The doubling cannot overflow
+        // because `cap <= isize::MAX` and the type of `cap` is `usize`.
+        let cap = cmp::max(self.cap * 2, required_cap);
+        let cap = cmp::max(Self::MIN_NON_ZERO_CAP, cap);
+
+        let new_layout = Layout::array::<T>(cap);
+
+        // `finish_grow` is non-generic over `T`.
+        let ptr = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?;
+        self.set_ptr_and_cap(ptr, cap);
+        Ok(())
+    }
+
+    // The constraints on this method are much the same as those on
+    // `grow_amortized`, but this method is usually instantiated less often so
+    // it's less critical.
+    fn grow_exact(&mut self, len: usize, additional: usize) -> Result<(), TryReserveError> {
+        if mem::size_of::<T>() == 0 {
+            // Since we return a capacity of `usize::MAX` when the type size is
+            // 0, getting to here necessarily means the `RawVec` is overfull.
+            return Err(CapacityOverflow.into());
+        }
+
+        let cap = len.checked_add(additional).ok_or(CapacityOverflow)?;
+        let new_layout = Layout::array::<T>(cap);
+
+        // `finish_grow` is non-generic over `T`.
+        let ptr = finish_grow(new_layout, self.current_memory(), &mut self.alloc)?;
+        self.set_ptr_and_cap(ptr, cap);
+        Ok(())
+    }
+
+    fn shrink(&mut self, cap: usize) -> Result<(), TryReserveError> {
+        assert!(cap <= self.capacity(), "Tried to shrink to a larger capacity");
+
+        let (ptr, layout) = if let Some(mem) = self.current_memory() { mem } else { return Ok(()) };
+
+        let ptr = unsafe {
+            // `Layout::array` cannot overflow here because it would have
+            // overflowed earlier when capacity was larger.
+            let new_layout = Layout::array::<T>(cap).unwrap_unchecked();
+            self.alloc
+                .shrink(ptr, layout, new_layout)
+                .map_err(|_| AllocError { layout: new_layout, non_exhaustive: () })?
+        };
+        self.set_ptr_and_cap(ptr, cap);
+        Ok(())
+    }
+}
+
+// This function is outside `RawVec` to minimize compile times. See the comment
+// above `RawVec::grow_amortized` for details. (The `A` parameter isn't
+// significant, because the number of different `A` types seen in practice is
+// much smaller than the number of `T` types.)
+#[inline(never)]
+fn finish_grow<A>(
+    new_layout: Result<Layout, LayoutError>,
+    current_memory: Option<(NonNull<u8>, Layout)>,
+    alloc: &mut A,
+) -> Result<NonNull<[u8]>, TryReserveError>
+where
+    A: Allocator,
+{
+    // Check for the error here to minimize the size of `RawVec::grow_*`.
+    let new_layout = new_layout.map_err(|_| CapacityOverflow)?;
+
+    alloc_guard(new_layout.size())?;
+
+    let memory = if let Some((ptr, old_layout)) = current_memory {
+        debug_assert_eq!(old_layout.align(), new_layout.align());
+        unsafe {
+            // The allocator checks for alignment equality
+            intrinsics::assume(old_layout.align() == new_layout.align());
+            alloc.grow(ptr, old_layout, new_layout)
+        }
+    } else {
+        alloc.allocate(new_layout)
+    };
+
+    memory.map_err(|_| AllocError { layout: new_layout, non_exhaustive: () }.into())
+}
+
+unsafe impl<#[may_dangle] T, A: Allocator> Drop for RawVec<T, A> {
+    /// Frees the memory owned by the `RawVec` *without* trying to drop its contents.
+    fn drop(&mut self) {
+        if let Some((ptr, layout)) = self.current_memory() {
+            unsafe { self.alloc.deallocate(ptr, layout) }
+        }
+    }
+}
+
+// Central function for reserve error handling.
+#[cfg(not(no_global_oom_handling))]
+#[inline]
+fn handle_reserve(result: Result<(), TryReserveError>) {
+    match result.map_err(|e| e.kind()) {
+        Err(CapacityOverflow) => capacity_overflow(),
+        Err(AllocError { layout, .. }) => handle_alloc_error(layout),
+        Ok(()) => { /* yay */ }
+    }
+}
+
+// We need to guarantee the following:
+// * We don't ever allocate `> isize::MAX` byte-size objects.
+// * We don't overflow `usize::MAX` and actually allocate too little.
+//
+// On 64-bit we just need to check for overflow since trying to allocate
+// `> isize::MAX` bytes will surely fail. On 32-bit and 16-bit we need to add
+// an extra guard for this in case we're running on a platform which can use
+// all 4GB in user-space, e.g., PAE or x32.
+
+#[inline]
+fn alloc_guard(alloc_size: usize) -> Result<(), TryReserveError> {
+    if usize::BITS < 64 && alloc_size > isize::MAX as usize {
+        Err(CapacityOverflow.into())
+    } else {
+        Ok(())
+    }
+}
+
+// One central function responsible for reporting capacity overflows. This'll
+// ensure that the code generation related to these panics is minimal as there's
+// only one location which panics rather than a bunch throughout the module.
+#[cfg(not(no_global_oom_handling))]
+fn capacity_overflow() -> ! {
+    panic!("capacity overflow");
+}
diff --git a/rust/alloc/slice.rs b/rust/alloc/slice.rs
new file mode 100644
index 000000000000..d53f6051f3a8
--- /dev/null
+++ b/rust/alloc/slice.rs
@@ -0,0 +1,1295 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! A dynamically-sized view into a contiguous sequence, `[T]`.
+//!
+//! *[See also the slice primitive type](slice).*
+//!
+//! Slices are a view into a block of memory represented as a pointer and a
+//! length.
+//!
+//! ```
+//! // slicing a Vec
+//! let vec = vec![1, 2, 3];
+//! let int_slice = &vec[..];
+//! // coercing an array to a slice
+//! let str_slice: &[&str] = &["one", "two", "three"];
+//! ```
+//!
+//! Slices are either mutable or shared. The shared slice type is `&[T]`,
+//! while the mutable slice type is `&mut [T]`, where `T` represents the element
+//! type. For example, you can mutate the block of memory that a mutable slice
+//! points to:
+//!
+//! ```
+//! let x = &mut [1, 2, 3];
+//! x[1] = 7;
+//! assert_eq!(x, &[1, 7, 3]);
+//! ```
+//!
+//! Here are some of the things this module contains:
+//!
+//! ## Structs
+//!
+//! There are several structs that are useful for slices, such as [`Iter`], which
+//! represents iteration over a slice.
+//!
+//! ## Trait Implementations
+//!
+//! There are several implementations of common traits for slices. Some examples
+//! include:
+//!
+//! * [`Clone`]
+//! * [`Eq`], [`Ord`] - for slices whose element type are [`Eq`] or [`Ord`].
+//! * [`Hash`] - for slices whose element type is [`Hash`].
+//!
+//! ## Iteration
+//!
+//! The slices implement `IntoIterator`. The iterator yields references to the
+//! slice elements.
+//!
+//! ```
+//! let numbers = &[0, 1, 2];
+//! for n in numbers {
+//!     println!("{n} is a number!");
+//! }
+//! ```
+//!
+//! The mutable slice yields mutable references to the elements:
+//!
+//! ```
+//! let mut scores = [7, 8, 9];
+//! for score in &mut scores[..] {
+//!     *score += 1;
+//! }
+//! ```
+//!
+//! This iterator yields mutable references to the slice's elements, so while
+//! the element type of the slice is `i32`, the element type of the iterator is
+//! `&mut i32`.
+//!
+//! * [`.iter`] and [`.iter_mut`] are the explicit methods to return the default
+//!   iterators.
+//! * Further methods that return iterators are [`.split`], [`.splitn`],
+//!   [`.chunks`], [`.windows`] and more.
+//!
+//! [`Hash`]: core::hash::Hash
+//! [`.iter`]: slice::iter
+//! [`.iter_mut`]: slice::iter_mut
+//! [`.split`]: slice::split
+//! [`.splitn`]: slice::splitn
+//! [`.chunks`]: slice::chunks
+//! [`.windows`]: slice::windows
+#![stable(feature = "rust1", since = "1.0.0")]
+// Many of the usings in this module are only used in the test configuration.
+// It's cleaner to just turn off the unused_imports warning than to fix them.
+#![cfg_attr(test, allow(unused_imports, dead_code))]
+
+use core::borrow::{Borrow, BorrowMut};
+#[cfg(not(no_global_oom_handling))]
+use core::cmp::Ordering::{self, Less};
+#[cfg(not(no_global_oom_handling))]
+use core::mem;
+#[cfg(not(no_global_oom_handling))]
+use core::mem::size_of;
+#[cfg(not(no_global_oom_handling))]
+use core::ptr;
+
+use crate::alloc::Allocator;
+use crate::alloc::Global;
+#[cfg(not(no_global_oom_handling))]
+use crate::borrow::ToOwned;
+use crate::boxed::Box;
+use crate::collections::TryReserveError;
+use crate::vec::Vec;
+
+#[unstable(feature = "slice_range", issue = "76393")]
+pub use core::slice::range;
+#[unstable(feature = "array_chunks", issue = "74985")]
+pub use core::slice::ArrayChunks;
+#[unstable(feature = "array_chunks", issue = "74985")]
+pub use core::slice::ArrayChunksMut;
+#[unstable(feature = "array_windows", issue = "75027")]
+pub use core::slice::ArrayWindows;
+#[stable(feature = "inherent_ascii_escape", since = "1.60.0")]
+pub use core::slice::EscapeAscii;
+#[stable(feature = "slice_get_slice", since = "1.28.0")]
+pub use core::slice::SliceIndex;
+#[stable(feature = "from_ref", since = "1.28.0")]
+pub use core::slice::{from_mut, from_ref};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{from_raw_parts, from_raw_parts_mut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{Chunks, Windows};
+#[stable(feature = "chunks_exact", since = "1.31.0")]
+pub use core::slice::{ChunksExact, ChunksExactMut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{ChunksMut, Split, SplitMut};
+#[unstable(feature = "slice_group_by", issue = "80552")]
+pub use core::slice::{GroupBy, GroupByMut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{Iter, IterMut};
+#[stable(feature = "rchunks", since = "1.31.0")]
+pub use core::slice::{RChunks, RChunksExact, RChunksExactMut, RChunksMut};
+#[stable(feature = "slice_rsplit", since = "1.27.0")]
+pub use core::slice::{RSplit, RSplitMut};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::slice::{RSplitN, RSplitNMut, SplitN, SplitNMut};
+#[stable(feature = "split_inclusive", since = "1.51.0")]
+pub use core::slice::{SplitInclusive, SplitInclusiveMut};
+
+////////////////////////////////////////////////////////////////////////////////
+// Basic slice extension methods
+////////////////////////////////////////////////////////////////////////////////
+
+// HACK(japaric) needed for the implementation of `vec!` macro during testing
+// N.B., see the `hack` module in this file for more details.
+#[cfg(test)]
+pub use hack::into_vec;
+
+// HACK(japaric) needed for the implementation of `Vec::clone` during testing
+// N.B., see the `hack` module in this file for more details.
+#[cfg(test)]
+pub use hack::to_vec;
+
+// HACK(japaric): With cfg(test) `impl [T]` is not available, these three
+// functions are actually methods that are in `impl [T]` but not in
+// `core::slice::SliceExt` - we need to supply these functions for the
+// `test_permutations` test
+pub(crate) mod hack {
+    use core::alloc::Allocator;
+
+    use crate::boxed::Box;
+    use crate::collections::TryReserveError;
+    use crate::vec::Vec;
+
+    // We shouldn't add inline attribute to this since this is used in
+    // `vec!` macro mostly and causes perf regression. See #71204 for
+    // discussion and perf results.
+    pub fn into_vec<T, A: Allocator>(b: Box<[T], A>) -> Vec<T, A> {
+        unsafe {
+            let len = b.len();
+            let (b, alloc) = Box::into_raw_with_allocator(b);
+            Vec::from_raw_parts_in(b as *mut T, len, len, alloc)
+        }
+    }
+
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    pub fn to_vec<T: ConvertVec, A: Allocator>(s: &[T], alloc: A) -> Vec<T, A> {
+        T::to_vec(s, alloc)
+    }
+
+    #[inline]
+    pub fn try_to_vec<T: TryConvertVec, A: Allocator>(s: &[T], alloc: A) -> Result<Vec<T, A>, TryReserveError> {
+        T::try_to_vec(s, alloc)
+    }
+
+    #[cfg(not(no_global_oom_handling))]
+    pub trait ConvertVec {
+        fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A>
+        where
+            Self: Sized;
+    }
+
+    pub trait TryConvertVec {
+        fn try_to_vec<A: Allocator>(s: &[Self], alloc: A) -> Result<Vec<Self, A>, TryReserveError>
+        where
+            Self: Sized;
+    }
+
+    #[cfg(not(no_global_oom_handling))]
+    impl<T: Clone> ConvertVec for T {
+        #[inline]
+        default fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> {
+            struct DropGuard<'a, T, A: Allocator> {
+                vec: &'a mut Vec<T, A>,
+                num_init: usize,
+            }
+            impl<'a, T, A: Allocator> Drop for DropGuard<'a, T, A> {
+                #[inline]
+                fn drop(&mut self) {
+                    // SAFETY:
+                    // items were marked initialized in the loop below
+                    unsafe {
+                        self.vec.set_len(self.num_init);
+                    }
+                }
+            }
+            let mut vec = Vec::with_capacity_in(s.len(), alloc);
+            let mut guard = DropGuard { vec: &mut vec, num_init: 0 };
+            let slots = guard.vec.spare_capacity_mut();
+            // .take(slots.len()) is necessary for LLVM to remove bounds checks
+            // and has better codegen than zip.
+            for (i, b) in s.iter().enumerate().take(slots.len()) {
+                guard.num_init = i;
+                slots[i].write(b.clone());
+            }
+            core::mem::forget(guard);
+            // SAFETY:
+            // the vec was allocated and initialized above to at least this length.
+            unsafe {
+                vec.set_len(s.len());
+            }
+            vec
+        }
+    }
+
+    #[cfg(not(no_global_oom_handling))]
+    impl<T: Copy> ConvertVec for T {
+        #[inline]
+        fn to_vec<A: Allocator>(s: &[Self], alloc: A) -> Vec<Self, A> {
+            let mut v = Vec::with_capacity_in(s.len(), alloc);
+            // SAFETY:
+            // allocated above with the capacity of `s`, and initialize to `s.len()` in
+            // ptr::copy_to_non_overlapping below.
+            unsafe {
+                s.as_ptr().copy_to_nonoverlapping(v.as_mut_ptr(), s.len());
+                v.set_len(s.len());
+            }
+            v
+        }
+    }
+
+    impl<T: Clone> TryConvertVec for T {
+        #[inline]
+        default fn try_to_vec<A: Allocator>(s: &[Self], alloc: A) -> Result<Vec<Self, A>, TryReserveError> {
+            struct DropGuard<'a, T, A: Allocator> {
+                vec: &'a mut Vec<T, A>,
+                num_init: usize,
+            }
+            impl<'a, T, A: Allocator> Drop for DropGuard<'a, T, A> {
+                #[inline]
+                fn drop(&mut self) {
+                    // SAFETY:
+                    // items were marked initialized in the loop below
+                    unsafe {
+                        self.vec.set_len(self.num_init);
+                    }
+                }
+            }
+            let mut vec = Vec::try_with_capacity_in(s.len(), alloc)?;
+            let mut guard = DropGuard { vec: &mut vec, num_init: 0 };
+            let slots = guard.vec.spare_capacity_mut();
+            // .take(slots.len()) is necessary for LLVM to remove bounds checks
+            // and has better codegen than zip.
+            for (i, b) in s.iter().enumerate().take(slots.len()) {
+                guard.num_init = i;
+                slots[i].write(b.clone());
+            }
+            core::mem::forget(guard);
+            // SAFETY:
+            // the vec was allocated and initialized above to at least this length.
+            unsafe {
+                vec.set_len(s.len());
+            }
+            Ok(vec)
+        }
+    }
+}
+
+#[cfg(not(test))]
+impl<T> [T] {
+    /// Sorts the slice.
+    ///
+    /// This sort is stable (i.e., does not reorder equal elements) and *O*(*n* \* log(*n*)) worst-case.
+    ///
+    /// When applicable, unstable sorting is preferred because it is generally faster than stable
+    /// sorting and it doesn't allocate auxiliary memory.
+    /// See [`sort_unstable`](slice::sort_unstable).
+    ///
+    /// # Current implementation
+    ///
+    /// The current algorithm is an adaptive, iterative merge sort inspired by
+    /// [timsort](https://en.wikipedia.org/wiki/Timsort).
+    /// It is designed to be very fast in cases where the slice is nearly sorted, or consists of
+    /// two or more sorted sequences concatenated one after another.
+    ///
+    /// Also, it allocates temporary storage half the size of `self`, but for short slices a
+    /// non-allocating insertion sort is used instead.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = [-5, 4, 1, -3, 2];
+    ///
+    /// v.sort();
+    /// assert!(v == [-5, -3, 1, 2, 4]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn sort(&mut self)
+    where
+        T: Ord,
+    {
+        merge_sort(self, |a, b| a.lt(b));
+    }
+
+    /// Sorts the slice with a comparator function.
+    ///
+    /// This sort is stable (i.e., does not reorder equal elements) and *O*(*n* \* log(*n*)) worst-case.
+    ///
+    /// The comparator function must define a total ordering for the elements in the slice. If
+    /// the ordering is not total, the order of the elements is unspecified. An order is a
+    /// total order if it is (for all `a`, `b` and `c`):
+    ///
+    /// * total and antisymmetric: exactly one of `a < b`, `a == b` or `a > b` is true, and
+    /// * transitive, `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`.
+    ///
+    /// For example, while [`f64`] doesn't implement [`Ord`] because `NaN != NaN`, we can use
+    /// `partial_cmp` as our sort function when we know the slice doesn't contain a `NaN`.
+    ///
+    /// ```
+    /// let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0];
+    /// floats.sort_by(|a, b| a.partial_cmp(b).unwrap());
+    /// assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]);
+    /// ```
+    ///
+    /// When applicable, unstable sorting is preferred because it is generally faster than stable
+    /// sorting and it doesn't allocate auxiliary memory.
+    /// See [`sort_unstable_by`](slice::sort_unstable_by).
+    ///
+    /// # Current implementation
+    ///
+    /// The current algorithm is an adaptive, iterative merge sort inspired by
+    /// [timsort](https://en.wikipedia.org/wiki/Timsort).
+    /// It is designed to be very fast in cases where the slice is nearly sorted, or consists of
+    /// two or more sorted sequences concatenated one after another.
+    ///
+    /// Also, it allocates temporary storage half the size of `self`, but for short slices a
+    /// non-allocating insertion sort is used instead.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = [5, 4, 1, 3, 2];
+    /// v.sort_by(|a, b| a.cmp(b));
+    /// assert!(v == [1, 2, 3, 4, 5]);
+    ///
+    /// // reverse sorting
+    /// v.sort_by(|a, b| b.cmp(a));
+    /// assert!(v == [5, 4, 3, 2, 1]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn sort_by<F>(&mut self, mut compare: F)
+    where
+        F: FnMut(&T, &T) -> Ordering,
+    {
+        merge_sort(self, |a, b| compare(a, b) == Less);
+    }
+
+    /// Sorts the slice with a key extraction function.
+    ///
+    /// This sort is stable (i.e., does not reorder equal elements) and *O*(*m* \* *n* \* log(*n*))
+    /// worst-case, where the key function is *O*(*m*).
+    ///
+    /// For expensive key functions (e.g. functions that are not simple property accesses or
+    /// basic operations), [`sort_by_cached_key`](slice::sort_by_cached_key) is likely to be
+    /// significantly faster, as it does not recompute element keys.
+    ///
+    /// When applicable, unstable sorting is preferred because it is generally faster than stable
+    /// sorting and it doesn't allocate auxiliary memory.
+    /// See [`sort_unstable_by_key`](slice::sort_unstable_by_key).
+    ///
+    /// # Current implementation
+    ///
+    /// The current algorithm is an adaptive, iterative merge sort inspired by
+    /// [timsort](https://en.wikipedia.org/wiki/Timsort).
+    /// It is designed to be very fast in cases where the slice is nearly sorted, or consists of
+    /// two or more sorted sequences concatenated one after another.
+    ///
+    /// Also, it allocates temporary storage half the size of `self`, but for short slices a
+    /// non-allocating insertion sort is used instead.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = [-5i32, 4, 1, -3, 2];
+    ///
+    /// v.sort_by_key(|k| k.abs());
+    /// assert!(v == [1, 2, -3, 4, -5]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[stable(feature = "slice_sort_by_key", since = "1.7.0")]
+    #[inline]
+    pub fn sort_by_key<K, F>(&mut self, mut f: F)
+    where
+        F: FnMut(&T) -> K,
+        K: Ord,
+    {
+        merge_sort(self, |a, b| f(a).lt(&f(b)));
+    }
+
+    /// Sorts the slice with a key extraction function.
+    ///
+    /// During sorting, the key function is called at most once per element, by using
+    /// temporary storage to remember the results of key evaluation.
+    /// The order of calls to the key function is unspecified and may change in future versions
+    /// of the standard library.
+    ///
+    /// This sort is stable (i.e., does not reorder equal elements) and *O*(*m* \* *n* + *n* \* log(*n*))
+    /// worst-case, where the key function is *O*(*m*).
+    ///
+    /// For simple key functions (e.g., functions that are property accesses or
+    /// basic operations), [`sort_by_key`](slice::sort_by_key) is likely to be
+    /// faster.
+    ///
+    /// # Current implementation
+    ///
+    /// The current algorithm is based on [pattern-defeating quicksort][pdqsort] by Orson Peters,
+    /// which combines the fast average case of randomized quicksort with the fast worst case of
+    /// heapsort, while achieving linear time on slices with certain patterns. It uses some
+    /// randomization to avoid degenerate cases, but with a fixed seed to always provide
+    /// deterministic behavior.
+    ///
+    /// In the worst case, the algorithm allocates temporary storage in a `Vec<(K, usize)>` the
+    /// length of the slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = [-5i32, 4, 32, -3, 2];
+    ///
+    /// v.sort_by_cached_key(|k| k.to_string());
+    /// assert!(v == [-3, -5, 2, 32, 4]);
+    /// ```
+    ///
+    /// [pdqsort]: https://github.com/orlp/pdqsort
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[stable(feature = "slice_sort_by_cached_key", since = "1.34.0")]
+    #[inline]
+    pub fn sort_by_cached_key<K, F>(&mut self, f: F)
+    where
+        F: FnMut(&T) -> K,
+        K: Ord,
+    {
+        // Helper macro for indexing our vector by the smallest possible type, to reduce allocation.
+        macro_rules! sort_by_key {
+            ($t:ty, $slice:ident, $f:ident) => {{
+                let mut indices: Vec<_> =
+                    $slice.iter().map($f).enumerate().map(|(i, k)| (k, i as $t)).collect();
+                // The elements of `indices` are unique, as they are indexed, so any sort will be
+                // stable with respect to the original slice. We use `sort_unstable` here because
+                // it requires less memory allocation.
+                indices.sort_unstable();
+                for i in 0..$slice.len() {
+                    let mut index = indices[i].1;
+                    while (index as usize) < i {
+                        index = indices[index as usize].1;
+                    }
+                    indices[i].1 = index;
+                    $slice.swap(i, index as usize);
+                }
+            }};
+        }
+
+        let sz_u8 = mem::size_of::<(K, u8)>();
+        let sz_u16 = mem::size_of::<(K, u16)>();
+        let sz_u32 = mem::size_of::<(K, u32)>();
+        let sz_usize = mem::size_of::<(K, usize)>();
+
+        let len = self.len();
+        if len < 2 {
+            return;
+        }
+        if sz_u8 < sz_u16 && len <= (u8::MAX as usize) {
+            return sort_by_key!(u8, self, f);
+        }
+        if sz_u16 < sz_u32 && len <= (u16::MAX as usize) {
+            return sort_by_key!(u16, self, f);
+        }
+        if sz_u32 < sz_usize && len <= (u32::MAX as usize) {
+            return sort_by_key!(u32, self, f);
+        }
+        sort_by_key!(usize, self, f)
+    }
+
+    /// Copies `self` into a new `Vec`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let s = [10, 40, 30];
+    /// let x = s.to_vec();
+    /// // Here, `s` and `x` can be modified independently.
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[rustc_conversion_suggestion]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn to_vec(&self) -> Vec<T>
+    where
+        T: Clone,
+    {
+        self.to_vec_in(Global)
+    }
+
+    /// Tries to copy `self` into a new `Vec`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let s = [10, 40, 30];
+    /// let x = s.try_to_vec().unwrap();
+    /// // Here, `s` and `x` can be modified independently.
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_to_vec(&self) -> Result<Vec<T>, TryReserveError>
+    where
+        T: Clone,
+    {
+        self.try_to_vec_in(Global)
+    }
+
+    /// Copies `self` into a new `Vec` with an allocator.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let s = [10, 40, 30];
+    /// let x = s.to_vec_in(System);
+    /// // Here, `s` and `x` can be modified independently.
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[inline]
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    pub fn to_vec_in<A: Allocator>(&self, alloc: A) -> Vec<T, A>
+    where
+        T: Clone,
+    {
+        // N.B., see the `hack` module in this file for more details.
+        hack::to_vec(self, alloc)
+    }
+
+    /// Tries to copy `self` into a new `Vec` with an allocator.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let s = [10, 40, 30];
+    /// let x = s.try_to_vec_in(System).unwrap();
+    /// // Here, `s` and `x` can be modified independently.
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_to_vec_in<A: Allocator>(&self, alloc: A) -> Result<Vec<T, A>, TryReserveError>
+    where
+        T: Clone,
+    {
+        // N.B., see the `hack` module in this file for more details.
+        hack::try_to_vec(self, alloc)
+    }
+
+    /// Converts `self` into a vector without clones or allocation.
+    ///
+    /// The resulting vector can be converted back into a box via
+    /// `Vec<T>`'s `into_boxed_slice` method.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let s: Box<[i32]> = Box::new([10, 40, 30]);
+    /// let x = s.into_vec();
+    /// // `s` cannot be used anymore because it has been converted into `x`.
+    ///
+    /// assert_eq!(x, vec![10, 40, 30]);
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn into_vec<A: Allocator>(self: Box<Self, A>) -> Vec<T, A> {
+        // N.B., see the `hack` module in this file for more details.
+        hack::into_vec(self)
+    }
+
+    /// Creates a vector by repeating a slice `n` times.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the capacity would overflow.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);
+    /// ```
+    ///
+    /// A panic upon overflow:
+    ///
+    /// ```should_panic
+    /// // this will panic at runtime
+    /// b"0123456789abcdef".repeat(usize::MAX);
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "repeat_generic_slice", since = "1.40.0")]
+    pub fn repeat(&self, n: usize) -> Vec<T>
+    where
+        T: Copy,
+    {
+        if n == 0 {
+            return Vec::new();
+        }
+
+        // If `n` is larger than zero, it can be split as
+        // `n = 2^expn + rem (2^expn > rem, expn >= 0, rem >= 0)`.
+        // `2^expn` is the number represented by the leftmost '1' bit of `n`,
+        // and `rem` is the remaining part of `n`.
+
+        // Using `Vec` to access `set_len()`.
+        let capacity = self.len().checked_mul(n).expect("capacity overflow");
+        let mut buf = Vec::with_capacity(capacity);
+
+        // `2^expn` repetition is done by doubling `buf` `expn`-times.
+        buf.extend(self);
+        {
+            let mut m = n >> 1;
+            // If `m > 0`, there are remaining bits up to the leftmost '1'.
+            while m > 0 {
+                // `buf.extend(buf)`:
+                unsafe {
+                    ptr::copy_nonoverlapping(
+                        buf.as_ptr(),
+                        (buf.as_mut_ptr() as *mut T).add(buf.len()),
+                        buf.len(),
+                    );
+                    // `buf` has capacity of `self.len() * n`.
+                    let buf_len = buf.len();
+                    buf.set_len(buf_len * 2);
+                }
+
+                m >>= 1;
+            }
+        }
+
+        // `rem` (`= n - 2^expn`) repetition is done by copying
+        // first `rem` repetitions from `buf` itself.
+        let rem_len = capacity - buf.len(); // `self.len() * rem`
+        if rem_len > 0 {
+            // `buf.extend(buf[0 .. rem_len])`:
+            unsafe {
+                // This is non-overlapping since `2^expn > rem`.
+                ptr::copy_nonoverlapping(
+                    buf.as_ptr(),
+                    (buf.as_mut_ptr() as *mut T).add(buf.len()),
+                    rem_len,
+                );
+                // `buf.len() + rem_len` equals to `buf.capacity()` (`= self.len() * n`).
+                buf.set_len(capacity);
+            }
+        }
+        buf
+    }
+
+    /// Flattens a slice of `T` into a single value `Self::Output`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(["hello", "world"].concat(), "helloworld");
+    /// assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn concat<Item: ?Sized>(&self) -> <Self as Concat<Item>>::Output
+    where
+        Self: Concat<Item>,
+    {
+        Concat::concat(self)
+    }
+
+    /// Flattens a slice of `T` into a single value `Self::Output`, placing a
+    /// given separator between each.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(["hello", "world"].join(" "), "hello world");
+    /// assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
+    /// assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[stable(feature = "rename_connect_to_join", since = "1.3.0")]
+    pub fn join<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
+    where
+        Self: Join<Separator>,
+    {
+        Join::join(self, sep)
+    }
+
+    /// Flattens a slice of `T` into a single value `Self::Output`, placing a
+    /// given separator between each.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # #![allow(deprecated)]
+    /// assert_eq!(["hello", "world"].connect(" "), "hello world");
+    /// assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[deprecated(since = "1.3.0", note = "renamed to join")]
+    pub fn connect<Separator>(&self, sep: Separator) -> <Self as Join<Separator>>::Output
+    where
+        Self: Join<Separator>,
+    {
+        Join::join(self, sep)
+    }
+}
+
+#[cfg(not(test))]
+impl [u8] {
+    /// Returns a vector containing a copy of this slice where each byte
+    /// is mapped to its ASCII upper case equivalent.
+    ///
+    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
+    /// but non-ASCII letters are unchanged.
+    ///
+    /// To uppercase the value in-place, use [`make_ascii_uppercase`].
+    ///
+    /// [`make_ascii_uppercase`]: slice::make_ascii_uppercase
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "this returns the uppercase bytes as a new Vec, \
+                  without modifying the original"]
+    #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+    #[inline]
+    pub fn to_ascii_uppercase(&self) -> Vec<u8> {
+        let mut me = self.to_vec();
+        me.make_ascii_uppercase();
+        me
+    }
+
+    /// Returns a vector containing a copy of this slice where each byte
+    /// is mapped to its ASCII lower case equivalent.
+    ///
+    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
+    /// but non-ASCII letters are unchanged.
+    ///
+    /// To lowercase the value in-place, use [`make_ascii_lowercase`].
+    ///
+    /// [`make_ascii_lowercase`]: slice::make_ascii_lowercase
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "this returns the lowercase bytes as a new Vec, \
+                  without modifying the original"]
+    #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+    #[inline]
+    pub fn to_ascii_lowercase(&self) -> Vec<u8> {
+        let mut me = self.to_vec();
+        me.make_ascii_lowercase();
+        me
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Extension traits for slices over specific kinds of data
+////////////////////////////////////////////////////////////////////////////////
+
+/// Helper trait for [`[T]::concat`](slice::concat).
+///
+/// Note: the `Item` type parameter is not used in this trait,
+/// but it allows impls to be more generic.
+/// Without it, we get this error:
+///
+/// ```error
+/// error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predica
+///    --> src/liballoc/slice.rs:608:6
+///     |
+/// 608 | impl<T: Clone, V: Borrow<[T]>> Concat for [V] {
+///     |      ^ unconstrained type parameter
+/// ```
+///
+/// This is because there could exist `V` types with multiple `Borrow<[_]>` impls,
+/// such that multiple `T` types would apply:
+///
+/// ```
+/// # #[allow(dead_code)]
+/// pub struct Foo(Vec<u32>, Vec<String>);
+///
+/// impl std::borrow::Borrow<[u32]> for Foo {
+///     fn borrow(&self) -> &[u32] { &self.0 }
+/// }
+///
+/// impl std::borrow::Borrow<[String]> for Foo {
+///     fn borrow(&self) -> &[String] { &self.1 }
+/// }
+/// ```
+#[unstable(feature = "slice_concat_trait", issue = "27747")]
+pub trait Concat<Item: ?Sized> {
+    #[unstable(feature = "slice_concat_trait", issue = "27747")]
+    /// The resulting type after concatenation
+    type Output;
+
+    /// Implementation of [`[T]::concat`](slice::concat)
+    #[unstable(feature = "slice_concat_trait", issue = "27747")]
+    fn concat(slice: &Self) -> Self::Output;
+}
+
+/// Helper trait for [`[T]::join`](slice::join)
+#[unstable(feature = "slice_concat_trait", issue = "27747")]
+pub trait Join<Separator> {
+    #[unstable(feature = "slice_concat_trait", issue = "27747")]
+    /// The resulting type after concatenation
+    type Output;
+
+    /// Implementation of [`[T]::join`](slice::join)
+    #[unstable(feature = "slice_concat_trait", issue = "27747")]
+    fn join(slice: &Self, sep: Separator) -> Self::Output;
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> Concat<T> for [V] {
+    type Output = Vec<T>;
+
+    fn concat(slice: &Self) -> Vec<T> {
+        let size = slice.iter().map(|slice| slice.borrow().len()).sum();
+        let mut result = Vec::with_capacity(size);
+        for v in slice {
+            result.extend_from_slice(v.borrow())
+        }
+        result
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> Join<&T> for [V] {
+    type Output = Vec<T>;
+
+    fn join(slice: &Self, sep: &T) -> Vec<T> {
+        let mut iter = slice.iter();
+        let first = match iter.next() {
+            Some(first) => first,
+            None => return vec![],
+        };
+        let size = slice.iter().map(|v| v.borrow().len()).sum::<usize>() + slice.len() - 1;
+        let mut result = Vec::with_capacity(size);
+        result.extend_from_slice(first.borrow());
+
+        for v in iter {
+            result.push(sep.clone());
+            result.extend_from_slice(v.borrow())
+        }
+        result
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<T: Clone, V: Borrow<[T]>> Join<&[T]> for [V] {
+    type Output = Vec<T>;
+
+    fn join(slice: &Self, sep: &[T]) -> Vec<T> {
+        let mut iter = slice.iter();
+        let first = match iter.next() {
+            Some(first) => first,
+            None => return vec![],
+        };
+        let size =
+            slice.iter().map(|v| v.borrow().len()).sum::<usize>() + sep.len() * (slice.len() - 1);
+        let mut result = Vec::with_capacity(size);
+        result.extend_from_slice(first.borrow());
+
+        for v in iter {
+            result.extend_from_slice(sep);
+            result.extend_from_slice(v.borrow())
+        }
+        result
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Standard trait implementations for slices
+////////////////////////////////////////////////////////////////////////////////
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> Borrow<[T]> for Vec<T> {
+    fn borrow(&self) -> &[T] {
+        &self[..]
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> BorrowMut<[T]> for Vec<T> {
+    fn borrow_mut(&mut self) -> &mut [T] {
+        &mut self[..]
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone> ToOwned for [T] {
+    type Owned = Vec<T>;
+    #[cfg(not(test))]
+    fn to_owned(&self) -> Vec<T> {
+        self.to_vec()
+    }
+
+    #[cfg(test)]
+    fn to_owned(&self) -> Vec<T> {
+        hack::to_vec(self, Global)
+    }
+
+    fn clone_into(&self, target: &mut Vec<T>) {
+        // drop anything in target that will not be overwritten
+        target.truncate(self.len());
+
+        // target.len <= self.len due to the truncate above, so the
+        // slices here are always in-bounds.
+        let (init, tail) = self.split_at(target.len());
+
+        // reuse the contained values' allocations/resources.
+        target.clone_from_slice(init);
+        target.extend_from_slice(tail);
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Sorting
+////////////////////////////////////////////////////////////////////////////////
+
+/// Inserts `v[0]` into pre-sorted sequence `v[1..]` so that whole `v[..]` becomes sorted.
+///
+/// This is the integral subroutine of insertion sort.
+#[cfg(not(no_global_oom_handling))]
+fn insert_head<T, F>(v: &mut [T], is_less: &mut F)
+where
+    F: FnMut(&T, &T) -> bool,
+{
+    if v.len() >= 2 && is_less(&v[1], &v[0]) {
+        unsafe {
+            // There are three ways to implement insertion here:
+            //
+            // 1. Swap adjacent elements until the first one gets to its final destination.
+            //    However, this way we copy data around more than is necessary. If elements are big
+            //    structures (costly to copy), this method will be slow.
+            //
+            // 2. Iterate until the right place for the first element is found. Then shift the
+            //    elements succeeding it to make room for it and finally place it into the
+            //    remaining hole. This is a good method.
+            //
+            // 3. Copy the first element into a temporary variable. Iterate until the right place
+            //    for it is found. As we go along, copy every traversed element into the slot
+            //    preceding it. Finally, copy data from the temporary variable into the remaining
+            //    hole. This method is very good. Benchmarks demonstrated slightly better
+            //    performance than with the 2nd method.
+            //
+            // All methods were benchmarked, and the 3rd showed best results. So we chose that one.
+            let tmp = mem::ManuallyDrop::new(ptr::read(&v[0]));
+
+            // Intermediate state of the insertion process is always tracked by `hole`, which
+            // serves two purposes:
+            // 1. Protects integrity of `v` from panics in `is_less`.
+            // 2. Fills the remaining hole in `v` in the end.
+            //
+            // Panic safety:
+            //
+            // If `is_less` panics at any point during the process, `hole` will get dropped and
+            // fill the hole in `v` with `tmp`, thus ensuring that `v` still holds every object it
+            // initially held exactly once.
+            let mut hole = InsertionHole { src: &*tmp, dest: &mut v[1] };
+            ptr::copy_nonoverlapping(&v[1], &mut v[0], 1);
+
+            for i in 2..v.len() {
+                if !is_less(&v[i], &*tmp) {
+                    break;
+                }
+                ptr::copy_nonoverlapping(&v[i], &mut v[i - 1], 1);
+                hole.dest = &mut v[i];
+            }
+            // `hole` gets dropped and thus copies `tmp` into the remaining hole in `v`.
+        }
+    }
+
+    // When dropped, copies from `src` into `dest`.
+    struct InsertionHole<T> {
+        src: *const T,
+        dest: *mut T,
+    }
+
+    impl<T> Drop for InsertionHole<T> {
+        fn drop(&mut self) {
+            unsafe {
+                ptr::copy_nonoverlapping(self.src, self.dest, 1);
+            }
+        }
+    }
+}
+
+/// Merges non-decreasing runs `v[..mid]` and `v[mid..]` using `buf` as temporary storage, and
+/// stores the result into `v[..]`.
+///
+/// # Safety
+///
+/// The two slices must be non-empty and `mid` must be in bounds. Buffer `buf` must be long enough
+/// to hold a copy of the shorter slice. Also, `T` must not be a zero-sized type.
+#[cfg(not(no_global_oom_handling))]
+unsafe fn merge<T, F>(v: &mut [T], mid: usize, buf: *mut T, is_less: &mut F)
+where
+    F: FnMut(&T, &T) -> bool,
+{
+    let len = v.len();
+    let v = v.as_mut_ptr();
+    let (v_mid, v_end) = unsafe { (v.add(mid), v.add(len)) };
+
+    // The merge process first copies the shorter run into `buf`. Then it traces the newly copied
+    // run and the longer run forwards (or backwards), comparing their next unconsumed elements and
+    // copying the lesser (or greater) one into `v`.
+    //
+    // As soon as the shorter run is fully consumed, the process is done. If the longer run gets
+    // consumed first, then we must copy whatever is left of the shorter run into the remaining
+    // hole in `v`.
+    //
+    // Intermediate state of the process is always tracked by `hole`, which serves two purposes:
+    // 1. Protects integrity of `v` from panics in `is_less`.
+    // 2. Fills the remaining hole in `v` if the longer run gets consumed first.
+    //
+    // Panic safety:
+    //
+    // If `is_less` panics at any point during the process, `hole` will get dropped and fill the
+    // hole in `v` with the unconsumed range in `buf`, thus ensuring that `v` still holds every
+    // object it initially held exactly once.
+    let mut hole;
+
+    if mid <= len - mid {
+        // The left run is shorter.
+        unsafe {
+            ptr::copy_nonoverlapping(v, buf, mid);
+            hole = MergeHole { start: buf, end: buf.add(mid), dest: v };
+        }
+
+        // Initially, these pointers point to the beginnings of their arrays.
+        let left = &mut hole.start;
+        let mut right = v_mid;
+        let out = &mut hole.dest;
+
+        while *left < hole.end && right < v_end {
+            // Consume the lesser side.
+            // If equal, prefer the left run to maintain stability.
+            unsafe {
+                let to_copy = if is_less(&*right, &**left) {
+                    get_and_increment(&mut right)
+                } else {
+                    get_and_increment(left)
+                };
+                ptr::copy_nonoverlapping(to_copy, get_and_increment(out), 1);
+            }
+        }
+    } else {
+        // The right run is shorter.
+        unsafe {
+            ptr::copy_nonoverlapping(v_mid, buf, len - mid);
+            hole = MergeHole { start: buf, end: buf.add(len - mid), dest: v_mid };
+        }
+
+        // Initially, these pointers point past the ends of their arrays.
+        let left = &mut hole.dest;
+        let right = &mut hole.end;
+        let mut out = v_end;
+
+        while v < *left && buf < *right {
+            // Consume the greater side.
+            // If equal, prefer the right run to maintain stability.
+            unsafe {
+                let to_copy = if is_less(&*right.offset(-1), &*left.offset(-1)) {
+                    decrement_and_get(left)
+                } else {
+                    decrement_and_get(right)
+                };
+                ptr::copy_nonoverlapping(to_copy, decrement_and_get(&mut out), 1);
+            }
+        }
+    }
+    // Finally, `hole` gets dropped. If the shorter run was not fully consumed, whatever remains of
+    // it will now be copied into the hole in `v`.
+
+    unsafe fn get_and_increment<T>(ptr: &mut *mut T) -> *mut T {
+        let old = *ptr;
+        *ptr = unsafe { ptr.offset(1) };
+        old
+    }
+
+    unsafe fn decrement_and_get<T>(ptr: &mut *mut T) -> *mut T {
+        *ptr = unsafe { ptr.offset(-1) };
+        *ptr
+    }
+
+    // When dropped, copies the range `start..end` into `dest..`.
+    struct MergeHole<T> {
+        start: *mut T,
+        end: *mut T,
+        dest: *mut T,
+    }
+
+    impl<T> Drop for MergeHole<T> {
+        fn drop(&mut self) {
+            // `T` is not a zero-sized type, and these are pointers into a slice's elements.
+            unsafe {
+                let len = self.end.sub_ptr(self.start);
+                ptr::copy_nonoverlapping(self.start, self.dest, len);
+            }
+        }
+    }
+}
+
+/// This merge sort borrows some (but not all) ideas from TimSort, which is described in detail
+/// [here](https://github.com/python/cpython/blob/main/Objects/listsort.txt).
+///
+/// The algorithm identifies strictly descending and non-descending subsequences, which are called
+/// natural runs. There is a stack of pending runs yet to be merged. Each newly found run is pushed
+/// onto the stack, and then some pairs of adjacent runs are merged until these two invariants are
+/// satisfied:
+///
+/// 1. for every `i` in `1..runs.len()`: `runs[i - 1].len > runs[i].len`
+/// 2. for every `i` in `2..runs.len()`: `runs[i - 2].len > runs[i - 1].len + runs[i].len`
+///
+/// The invariants ensure that the total running time is *O*(*n* \* log(*n*)) worst-case.
+#[cfg(not(no_global_oom_handling))]
+fn merge_sort<T, F>(v: &mut [T], mut is_less: F)
+where
+    F: FnMut(&T, &T) -> bool,
+{
+    // Slices of up to this length get sorted using insertion sort.
+    const MAX_INSERTION: usize = 20;
+    // Very short runs are extended using insertion sort to span at least this many elements.
+    const MIN_RUN: usize = 10;
+
+    // Sorting has no meaningful behavior on zero-sized types.
+    if size_of::<T>() == 0 {
+        return;
+    }
+
+    let len = v.len();
+
+    // Short arrays get sorted in-place via insertion sort to avoid allocations.
+    if len <= MAX_INSERTION {
+        if len >= 2 {
+            for i in (0..len - 1).rev() {
+                insert_head(&mut v[i..], &mut is_less);
+            }
+        }
+        return;
+    }
+
+    // Allocate a buffer to use as scratch memory. We keep the length 0 so we can keep in it
+    // shallow copies of the contents of `v` without risking the dtors running on copies if
+    // `is_less` panics. When merging two sorted runs, this buffer holds a copy of the shorter run,
+    // which will always have length at most `len / 2`.
+    let mut buf = Vec::with_capacity(len / 2);
+
+    // In order to identify natural runs in `v`, we traverse it backwards. That might seem like a
+    // strange decision, but consider the fact that merges more often go in the opposite direction
+    // (forwards). According to benchmarks, merging forwards is slightly faster than merging
+    // backwards. To conclude, identifying runs by traversing backwards improves performance.
+    let mut runs = vec![];
+    let mut end = len;
+    while end > 0 {
+        // Find the next natural run, and reverse it if it's strictly descending.
+        let mut start = end - 1;
+        if start > 0 {
+            start -= 1;
+            unsafe {
+                if is_less(v.get_unchecked(start + 1), v.get_unchecked(start)) {
+                    while start > 0 && is_less(v.get_unchecked(start), v.get_unchecked(start - 1)) {
+                        start -= 1;
+                    }
+                    v[start..end].reverse();
+                } else {
+                    while start > 0 && !is_less(v.get_unchecked(start), v.get_unchecked(start - 1))
+                    {
+                        start -= 1;
+                    }
+                }
+            }
+        }
+
+        // Insert some more elements into the run if it's too short. Insertion sort is faster than
+        // merge sort on short sequences, so this significantly improves performance.
+        while start > 0 && end - start < MIN_RUN {
+            start -= 1;
+            insert_head(&mut v[start..end], &mut is_less);
+        }
+
+        // Push this run onto the stack.
+        runs.push(Run { start, len: end - start });
+        end = start;
+
+        // Merge some pairs of adjacent runs to satisfy the invariants.
+        while let Some(r) = collapse(&runs) {
+            let left = runs[r + 1];
+            let right = runs[r];
+            unsafe {
+                merge(
+                    &mut v[left.start..right.start + right.len],
+                    left.len,
+                    buf.as_mut_ptr(),
+                    &mut is_less,
+                );
+            }
+            runs[r] = Run { start: left.start, len: left.len + right.len };
+            runs.remove(r + 1);
+        }
+    }
+
+    // Finally, exactly one run must remain in the stack.
+    debug_assert!(runs.len() == 1 && runs[0].start == 0 && runs[0].len == len);
+
+    // Examines the stack of runs and identifies the next pair of runs to merge. More specifically,
+    // if `Some(r)` is returned, that means `runs[r]` and `runs[r + 1]` must be merged next. If the
+    // algorithm should continue building a new run instead, `None` is returned.
+    //
+    // TimSort is infamous for its buggy implementations, as described here:
+    // http://envisage-project.eu/timsort-specification-and-verification/
+    //
+    // The gist of the story is: we must enforce the invariants on the top four runs on the stack.
+    // Enforcing them on just top three is not sufficient to ensure that the invariants will still
+    // hold for *all* runs in the stack.
+    //
+    // This function correctly checks invariants for the top four runs. Additionally, if the top
+    // run starts at index 0, it will always demand a merge operation until the stack is fully
+    // collapsed, in order to complete the sort.
+    #[inline]
+    fn collapse(runs: &[Run]) -> Option<usize> {
+        let n = runs.len();
+        if n >= 2
+            && (runs[n - 1].start == 0
+                || runs[n - 2].len <= runs[n - 1].len
+                || (n >= 3 && runs[n - 3].len <= runs[n - 2].len + runs[n - 1].len)
+                || (n >= 4 && runs[n - 4].len <= runs[n - 3].len + runs[n - 2].len))
+        {
+            if n >= 3 && runs[n - 3].len < runs[n - 1].len { Some(n - 3) } else { Some(n - 2) }
+        } else {
+            None
+        }
+    }
+
+    #[derive(Clone, Copy)]
+    struct Run {
+        start: usize,
+        len: usize,
+    }
+}
diff --git a/rust/alloc/str.rs b/rust/alloc/str.rs
new file mode 100644
index 000000000000..4e3aec690fdb
--- /dev/null
+++ b/rust/alloc/str.rs
@@ -0,0 +1,641 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! Unicode string slices.
+//!
+//! *[See also the `str` primitive type](str).*
+//!
+//! The `&str` type is one of the two main string types, the other being `String`.
+//! Unlike its `String` counterpart, its contents are borrowed.
+//!
+//! # Basic Usage
+//!
+//! A basic string declaration of `&str` type:
+//!
+//! ```
+//! let hello_world = "Hello, World!";
+//! ```
+//!
+//! Here we have declared a string literal, also known as a string slice.
+//! String literals have a static lifetime, which means the string `hello_world`
+//! is guaranteed to be valid for the duration of the entire program.
+//! We can explicitly specify `hello_world`'s lifetime as well:
+//!
+//! ```
+//! let hello_world: &'static str = "Hello, world!";
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+// Many of the usings in this module are only used in the test configuration.
+// It's cleaner to just turn off the unused_imports warning than to fix them.
+#![allow(unused_imports)]
+
+use core::borrow::{Borrow, BorrowMut};
+use core::iter::FusedIterator;
+use core::mem;
+use core::ptr;
+use core::str::pattern::{DoubleEndedSearcher, Pattern, ReverseSearcher, Searcher};
+use core::unicode::conversions;
+
+use crate::borrow::ToOwned;
+use crate::boxed::Box;
+use crate::collections::TryReserveError;
+use crate::slice::{Concat, Join, SliceIndex};
+use crate::string::String;
+use crate::vec::Vec;
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::pattern;
+#[stable(feature = "encode_utf16", since = "1.8.0")]
+pub use core::str::EncodeUtf16;
+#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
+pub use core::str::SplitAsciiWhitespace;
+#[stable(feature = "split_inclusive", since = "1.51.0")]
+pub use core::str::SplitInclusive;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::SplitWhitespace;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{from_utf8, from_utf8_mut, Bytes, CharIndices, Chars};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{from_utf8_unchecked, from_utf8_unchecked_mut, ParseBoolError};
+#[stable(feature = "str_escape", since = "1.34.0")]
+pub use core::str::{EscapeDebug, EscapeDefault, EscapeUnicode};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{FromStr, Utf8Error};
+#[allow(deprecated)]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{Lines, LinesAny};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{MatchIndices, RMatchIndices};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{Matches, RMatches};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{RSplit, Split};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{RSplitN, SplitN};
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use core::str::{RSplitTerminator, SplitTerminator};
+
+/// Note: `str` in `Concat<str>` is not meaningful here.
+/// This type parameter of the trait only exists to enable another impl.
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<S: Borrow<str>> Concat<str> for [S] {
+    type Output = String;
+
+    fn concat(slice: &Self) -> String {
+        Join::join(slice, "")
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "slice_concat_ext", issue = "27747")]
+impl<S: Borrow<str>> Join<&str> for [S] {
+    type Output = String;
+
+    fn join(slice: &Self, sep: &str) -> String {
+        unsafe { String::from_utf8_unchecked(join_generic_copy(slice, sep.as_bytes())) }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+macro_rules! specialize_for_lengths {
+    ($separator:expr, $target:expr, $iter:expr; $($num:expr),*) => {{
+        let mut target = $target;
+        let iter = $iter;
+        let sep_bytes = $separator;
+        match $separator.len() {
+            $(
+                // loops with hardcoded sizes run much faster
+                // specialize the cases with small separator lengths
+                $num => {
+                    for s in iter {
+                        copy_slice_and_advance!(target, sep_bytes);
+                        let content_bytes = s.borrow().as_ref();
+                        copy_slice_and_advance!(target, content_bytes);
+                    }
+                },
+            )*
+            _ => {
+                // arbitrary non-zero size fallback
+                for s in iter {
+                    copy_slice_and_advance!(target, sep_bytes);
+                    let content_bytes = s.borrow().as_ref();
+                    copy_slice_and_advance!(target, content_bytes);
+                }
+            }
+        }
+        target
+    }}
+}
+
+#[cfg(not(no_global_oom_handling))]
+macro_rules! copy_slice_and_advance {
+    ($target:expr, $bytes:expr) => {
+        let len = $bytes.len();
+        let (head, tail) = { $target }.split_at_mut(len);
+        head.copy_from_slice($bytes);
+        $target = tail;
+    };
+}
+
+// Optimized join implementation that works for both Vec<T> (T: Copy) and String's inner vec
+// Currently (2018-05-13) there is a bug with type inference and specialization (see issue #36262)
+// For this reason SliceConcat<T> is not specialized for T: Copy and SliceConcat<str> is the
+// only user of this function. It is left in place for the time when that is fixed.
+//
+// the bounds for String-join are S: Borrow<str> and for Vec-join Borrow<[T]>
+// [T] and str both impl AsRef<[T]> for some T
+// => s.borrow().as_ref() and we always have slices
+#[cfg(not(no_global_oom_handling))]
+fn join_generic_copy<B, T, S>(slice: &[S], sep: &[T]) -> Vec<T>
+where
+    T: Copy,
+    B: AsRef<[T]> + ?Sized,
+    S: Borrow<B>,
+{
+    let sep_len = sep.len();
+    let mut iter = slice.iter();
+
+    // the first slice is the only one without a separator preceding it
+    let first = match iter.next() {
+        Some(first) => first,
+        None => return vec![],
+    };
+
+    // compute the exact total length of the joined Vec
+    // if the `len` calculation overflows, we'll panic
+    // we would have run out of memory anyway and the rest of the function requires
+    // the entire Vec pre-allocated for safety
+    let reserved_len = sep_len
+        .checked_mul(iter.len())
+        .and_then(|n| {
+            slice.iter().map(|s| s.borrow().as_ref().len()).try_fold(n, usize::checked_add)
+        })
+        .expect("attempt to join into collection with len > usize::MAX");
+
+    // prepare an uninitialized buffer
+    let mut result = Vec::with_capacity(reserved_len);
+    debug_assert!(result.capacity() >= reserved_len);
+
+    result.extend_from_slice(first.borrow().as_ref());
+
+    unsafe {
+        let pos = result.len();
+        let target = result.spare_capacity_mut().get_unchecked_mut(..reserved_len - pos);
+
+        // Convert the separator and slices to slices of MaybeUninit
+        // to simplify implementation in specialize_for_lengths
+        let sep_uninit = core::slice::from_raw_parts(sep.as_ptr().cast(), sep.len());
+        let iter_uninit = iter.map(|it| {
+            let it = it.borrow().as_ref();
+            core::slice::from_raw_parts(it.as_ptr().cast(), it.len())
+        });
+
+        // copy separator and slices over without bounds checks
+        // generate loops with hardcoded offsets for small separators
+        // massive improvements possible (~ x2)
+        let remain = specialize_for_lengths!(sep_uninit, target, iter_uninit; 0, 1, 2, 3, 4);
+
+        // A weird borrow implementation may return different
+        // slices for the length calculation and the actual copy.
+        // Make sure we don't expose uninitialized bytes to the caller.
+        let result_len = reserved_len - remain.len();
+        result.set_len(result_len);
+    }
+    result
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Borrow<str> for String {
+    #[inline]
+    fn borrow(&self) -> &str {
+        &self[..]
+    }
+}
+
+#[stable(feature = "string_borrow_mut", since = "1.36.0")]
+impl BorrowMut<str> for String {
+    #[inline]
+    fn borrow_mut(&mut self) -> &mut str {
+        &mut self[..]
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ToOwned for str {
+    type Owned = String;
+    #[inline]
+    fn to_owned(&self) -> String {
+        unsafe { String::from_utf8_unchecked(self.as_bytes().to_owned()) }
+    }
+
+    fn clone_into(&self, target: &mut String) {
+        let mut b = mem::take(target).into_bytes();
+        self.as_bytes().clone_into(&mut b);
+        *target = unsafe { String::from_utf8_unchecked(b) }
+    }
+}
+
+/// Methods for string slices.
+#[cfg(not(test))]
+impl str {
+    /// Converts a `Box<str>` into a `Box<[u8]>` without copying or allocating.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = "this is a string";
+    /// let boxed_str = s.to_owned().into_boxed_str();
+    /// let boxed_bytes = boxed_str.into_boxed_bytes();
+    /// assert_eq!(*boxed_bytes, *s.as_bytes());
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[stable(feature = "str_box_extras", since = "1.20.0")]
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[inline]
+    pub fn into_boxed_bytes(self: Box<str>) -> Box<[u8]> {
+        self.into()
+    }
+
+    /// Replaces all matches of a pattern with another string.
+    ///
+    /// `replace` creates a new [`String`], and copies the data from this string slice into it.
+    /// While doing so, it attempts to find matches of a pattern. If it finds any, it
+    /// replaces them with the replacement string slice.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = "this is old";
+    ///
+    /// assert_eq!("this is new", s.replace("old", "new"));
+    /// ```
+    ///
+    /// When the pattern doesn't match:
+    ///
+    /// ```
+    /// let s = "this is old";
+    /// assert_eq!(s, s.replace("cookie monster", "little lamb"));
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "this returns the replaced string as a new allocation, \
+                  without modifying the original"]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn replace<'a, P: Pattern<'a>>(&'a self, from: P, to: &str) -> String {
+        let mut result = String::new();
+        let mut last_end = 0;
+        for (start, part) in self.match_indices(from) {
+            result.push_str(unsafe { self.get_unchecked(last_end..start) });
+            result.push_str(to);
+            last_end = start + part.len();
+        }
+        result.push_str(unsafe { self.get_unchecked(last_end..self.len()) });
+        result
+    }
+
+    /// Replaces first N matches of a pattern with another string.
+    ///
+    /// `replacen` creates a new [`String`], and copies the data from this string slice into it.
+    /// While doing so, it attempts to find matches of a pattern. If it finds any, it
+    /// replaces them with the replacement string slice at most `count` times.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = "foo foo 123 foo";
+    /// assert_eq!("new new 123 foo", s.replacen("foo", "new", 2));
+    /// assert_eq!("faa fao 123 foo", s.replacen('o', "a", 3));
+    /// assert_eq!("foo foo new23 foo", s.replacen(char::is_numeric, "new", 1));
+    /// ```
+    ///
+    /// When the pattern doesn't match:
+    ///
+    /// ```
+    /// let s = "this is old";
+    /// assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "this returns the replaced string as a new allocation, \
+                  without modifying the original"]
+    #[stable(feature = "str_replacen", since = "1.16.0")]
+    pub fn replacen<'a, P: Pattern<'a>>(&'a self, pat: P, to: &str, count: usize) -> String {
+        // Hope to reduce the times of re-allocation
+        let mut result = String::with_capacity(32);
+        let mut last_end = 0;
+        for (start, part) in self.match_indices(pat).take(count) {
+            result.push_str(unsafe { self.get_unchecked(last_end..start) });
+            result.push_str(to);
+            last_end = start + part.len();
+        }
+        result.push_str(unsafe { self.get_unchecked(last_end..self.len()) });
+        result
+    }
+
+    /// Returns the lowercase equivalent of this string slice, as a new [`String`].
+    ///
+    /// 'Lowercase' is defined according to the terms of the Unicode Derived Core Property
+    /// `Lowercase`.
+    ///
+    /// Since some characters can expand into multiple characters when changing
+    /// the case, this function returns a [`String`] instead of modifying the
+    /// parameter in-place.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = "HELLO";
+    ///
+    /// assert_eq!("hello", s.to_lowercase());
+    /// ```
+    ///
+    /// A tricky example, with sigma:
+    ///
+    /// ```
+    /// let sigma = "Σ";
+    ///
+    /// assert_eq!("σ", sigma.to_lowercase());
+    ///
+    /// // but at the end of a word, it's ς, not σ:
+    /// let odysseus = "ὈΔΥΣΣΕΎΣ";
+    ///
+    /// assert_eq!("ὀδυσσεύς", odysseus.to_lowercase());
+    /// ```
+    ///
+    /// Languages without case are not changed:
+    ///
+    /// ```
+    /// let new_year = "农历新年";
+    ///
+    /// assert_eq!(new_year, new_year.to_lowercase());
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "this returns the lowercase string as a new String, \
+                  without modifying the original"]
+    #[stable(feature = "unicode_case_mapping", since = "1.2.0")]
+    pub fn to_lowercase(&self) -> String {
+        let mut s = String::with_capacity(self.len());
+        for (i, c) in self[..].char_indices() {
+            if c == 'Σ' {
+                // Σ maps to σ, except at the end of a word where it maps to ς.
+                // This is the only conditional (contextual) but language-independent mapping
+                // in `SpecialCasing.txt`,
+                // so hard-code it rather than have a generic "condition" mechanism.
+                // See https://github.com/rust-lang/rust/issues/26035
+                map_uppercase_sigma(self, i, &mut s)
+            } else {
+                match conversions::to_lower(c) {
+                    [a, '\0', _] => s.push(a),
+                    [a, b, '\0'] => {
+                        s.push(a);
+                        s.push(b);
+                    }
+                    [a, b, c] => {
+                        s.push(a);
+                        s.push(b);
+                        s.push(c);
+                    }
+                }
+            }
+        }
+        return s;
+
+        fn map_uppercase_sigma(from: &str, i: usize, to: &mut String) {
+            // See https://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G33992
+            // for the definition of `Final_Sigma`.
+            debug_assert!('Σ'.len_utf8() == 2);
+            let is_word_final = case_ignoreable_then_cased(from[..i].chars().rev())
+                && !case_ignoreable_then_cased(from[i + 2..].chars());
+            to.push_str(if is_word_final { "ς" } else { "σ" });
+        }
+
+        fn case_ignoreable_then_cased<I: Iterator<Item = char>>(iter: I) -> bool {
+            use core::unicode::{Case_Ignorable, Cased};
+            match iter.skip_while(|&c| Case_Ignorable(c)).next() {
+                Some(c) => Cased(c),
+                None => false,
+            }
+        }
+    }
+
+    /// Returns the uppercase equivalent of this string slice, as a new [`String`].
+    ///
+    /// 'Uppercase' is defined according to the terms of the Unicode Derived Core Property
+    /// `Uppercase`.
+    ///
+    /// Since some characters can expand into multiple characters when changing
+    /// the case, this function returns a [`String`] instead of modifying the
+    /// parameter in-place.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = "hello";
+    ///
+    /// assert_eq!("HELLO", s.to_uppercase());
+    /// ```
+    ///
+    /// Scripts without case are not changed:
+    ///
+    /// ```
+    /// let new_year = "农历新年";
+    ///
+    /// assert_eq!(new_year, new_year.to_uppercase());
+    /// ```
+    ///
+    /// One character can become multiple:
+    /// ```
+    /// let s = "tschüß";
+    ///
+    /// assert_eq!("TSCHÜSS", s.to_uppercase());
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "this returns the uppercase string as a new String, \
+                  without modifying the original"]
+    #[stable(feature = "unicode_case_mapping", since = "1.2.0")]
+    pub fn to_uppercase(&self) -> String {
+        let mut s = String::with_capacity(self.len());
+        for c in self[..].chars() {
+            match conversions::to_upper(c) {
+                [a, '\0', _] => s.push(a),
+                [a, b, '\0'] => {
+                    s.push(a);
+                    s.push(b);
+                }
+                [a, b, c] => {
+                    s.push(a);
+                    s.push(b);
+                    s.push(c);
+                }
+            }
+        }
+        s
+    }
+
+    /// Converts a [`Box<str>`] into a [`String`] without copying or allocating.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let string = String::from("birthday gift");
+    /// let boxed_str = string.clone().into_boxed_str();
+    ///
+    /// assert_eq!(boxed_str.into_string(), string);
+    /// ```
+    #[stable(feature = "box_str", since = "1.4.0")]
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[inline]
+    pub fn into_string(self: Box<str>) -> String {
+        let slice = Box::<[u8]>::from(self);
+        unsafe { String::from_utf8_unchecked(slice.into_vec()) }
+    }
+
+    /// Creates a new [`String`] by repeating a string `n` times.
+    ///
+    /// # Panics
+    ///
+    /// This function will panic if the capacity would overflow.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// assert_eq!("abc".repeat(4), String::from("abcabcabcabc"));
+    /// ```
+    ///
+    /// A panic upon overflow:
+    ///
+    /// ```should_panic
+    /// // this will panic at runtime
+    /// let huge = "0123456789abcdef".repeat(usize::MAX);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[must_use]
+    #[stable(feature = "repeat_str", since = "1.16.0")]
+    pub fn repeat(&self, n: usize) -> String {
+        unsafe { String::from_utf8_unchecked(self.as_bytes().repeat(n)) }
+    }
+
+    /// Returns a copy of this string where each character is mapped to its
+    /// ASCII upper case equivalent.
+    ///
+    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
+    /// but non-ASCII letters are unchanged.
+    ///
+    /// To uppercase the value in-place, use [`make_ascii_uppercase`].
+    ///
+    /// To uppercase ASCII characters in addition to non-ASCII characters, use
+    /// [`to_uppercase`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let s = "Grüße, Jürgen ❤";
+    ///
+    /// assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());
+    /// ```
+    ///
+    /// [`make_ascii_uppercase`]: str::make_ascii_uppercase
+    /// [`to_uppercase`]: #method.to_uppercase
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "to uppercase the value in-place, use `make_ascii_uppercase()`"]
+    #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+    #[inline]
+    pub fn to_ascii_uppercase(&self) -> String {
+        let mut bytes = self.as_bytes().to_vec();
+        bytes.make_ascii_uppercase();
+        // make_ascii_uppercase() preserves the UTF-8 invariant.
+        unsafe { String::from_utf8_unchecked(bytes) }
+    }
+
+    /// Returns a copy of this string where each character is mapped to its
+    /// ASCII lower case equivalent.
+    ///
+    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
+    /// but non-ASCII letters are unchanged.
+    ///
+    /// To lowercase the value in-place, use [`make_ascii_lowercase`].
+    ///
+    /// To lowercase ASCII characters in addition to non-ASCII characters, use
+    /// [`to_lowercase`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let s = "Grüße, Jürgen ❤";
+    ///
+    /// assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());
+    /// ```
+    ///
+    /// [`make_ascii_lowercase`]: str::make_ascii_lowercase
+    /// [`to_lowercase`]: #method.to_lowercase
+    #[cfg(not(no_global_oom_handling))]
+    #[rustc_allow_incoherent_impl]
+    #[must_use = "to lowercase the value in-place, use `make_ascii_lowercase()`"]
+    #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
+    #[inline]
+    pub fn to_ascii_lowercase(&self) -> String {
+        let mut bytes = self.as_bytes().to_vec();
+        bytes.make_ascii_lowercase();
+        // make_ascii_lowercase() preserves the UTF-8 invariant.
+        unsafe { String::from_utf8_unchecked(bytes) }
+    }
+
+    /// Tries to create a `String`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s: &str = "a";
+    /// let ss: String = s.try_to_owned().unwrap();
+    /// ```
+    #[rustc_allow_incoherent_impl]
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_to_owned(&self) -> Result<String, TryReserveError> {
+        unsafe { Ok(String::from_utf8_unchecked(self.as_bytes().try_to_vec()?)) }
+    }
+}
+
+/// Converts a boxed slice of bytes to a boxed string slice without checking
+/// that the string contains valid UTF-8.
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// let smile_utf8 = Box::new([226, 152, 186]);
+/// let smile = unsafe { std::str::from_boxed_utf8_unchecked(smile_utf8) };
+///
+/// assert_eq!("☺", &*smile);
+/// ```
+#[stable(feature = "str_box_extras", since = "1.20.0")]
+#[must_use]
+#[inline]
+pub unsafe fn from_boxed_utf8_unchecked(v: Box<[u8]>) -> Box<str> {
+    unsafe { Box::from_raw(Box::into_raw(v) as *mut str) }
+}
diff --git a/rust/alloc/string.rs b/rust/alloc/string.rs
new file mode 100644
index 000000000000..2ba7f30a7503
--- /dev/null
+++ b/rust/alloc/string.rs
@@ -0,0 +1,2944 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! A UTF-8–encoded, growable string.
+//!
+//! This module contains the [`String`] type, the [`ToString`] trait for
+//! converting to strings, and several error types that may result from
+//! working with [`String`]s.
+//!
+//! # Examples
+//!
+//! There are multiple ways to create a new [`String`] from a string literal:
+//!
+//! ```
+//! let s = "Hello".to_string();
+//!
+//! let s = String::from("world");
+//! let s: String = "also this".into();
+//! ```
+//!
+//! You can create a new [`String`] from an existing one by concatenating with
+//! `+`:
+//!
+//! ```
+//! let s = "Hello".to_string();
+//!
+//! let message = s + " world!";
+//! ```
+//!
+//! If you have a vector of valid UTF-8 bytes, you can make a [`String`] out of
+//! it. You can do the reverse too.
+//!
+//! ```
+//! let sparkle_heart = vec![240, 159, 146, 150];
+//!
+//! // We know these bytes are valid, so we'll use `unwrap()`.
+//! let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();
+//!
+//! assert_eq!("💖", sparkle_heart);
+//!
+//! let bytes = sparkle_heart.into_bytes();
+//!
+//! assert_eq!(bytes, [240, 159, 146, 150]);
+//! ```
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[cfg(not(no_global_oom_handling))]
+use core::char::{decode_utf16, REPLACEMENT_CHARACTER};
+use core::fmt;
+use core::hash;
+#[cfg(not(no_global_oom_handling))]
+use core::iter::{from_fn, FromIterator};
+use core::iter::FusedIterator;
+#[cfg(not(no_global_oom_handling))]
+use core::ops::Add;
+#[cfg(not(no_global_oom_handling))]
+use core::ops::AddAssign;
+#[cfg(not(no_global_oom_handling))]
+use core::ops::Bound::{Excluded, Included, Unbounded};
+use core::ops::{self, Index, IndexMut, Range, RangeBounds};
+use core::ptr;
+use core::slice;
+#[cfg(not(no_global_oom_handling))]
+use core::str::lossy;
+use core::str::pattern::Pattern;
+
+#[cfg(not(no_global_oom_handling))]
+use crate::borrow::{Cow, ToOwned};
+use crate::boxed::Box;
+use crate::collections::TryReserveError;
+use crate::str::{self, Chars, Utf8Error};
+#[cfg(not(no_global_oom_handling))]
+use crate::str::{from_boxed_utf8_unchecked, FromStr};
+use crate::vec::Vec;
+
+/// A UTF-8–encoded, growable string.
+///
+/// The `String` type is the most common string type that has ownership over the
+/// contents of the string. It has a close relationship with its borrowed
+/// counterpart, the primitive [`str`].
+///
+/// # Examples
+///
+/// You can create a `String` from [a literal string][`&str`] with [`String::from`]:
+///
+/// [`String::from`]: From::from
+///
+/// ```
+/// let hello = String::from("Hello, world!");
+/// ```
+///
+/// You can append a [`char`] to a `String` with the [`push`] method, and
+/// append a [`&str`] with the [`push_str`] method:
+///
+/// ```
+/// let mut hello = String::from("Hello, ");
+///
+/// hello.push('w');
+/// hello.push_str("orld!");
+/// ```
+///
+/// [`push`]: String::push
+/// [`push_str`]: String::push_str
+///
+/// If you have a vector of UTF-8 bytes, you can create a `String` from it with
+/// the [`from_utf8`] method:
+///
+/// ```
+/// // some bytes, in a vector
+/// let sparkle_heart = vec![240, 159, 146, 150];
+///
+/// // We know these bytes are valid, so we'll use `unwrap()`.
+/// let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();
+///
+/// assert_eq!("💖", sparkle_heart);
+/// ```
+///
+/// [`from_utf8`]: String::from_utf8
+///
+/// # UTF-8
+///
+/// `String`s are always valid UTF-8. If you need a non-UTF-8 string, consider
+/// [`OsString`]. It is similar, but without the UTF-8 constraint. Because UTF-8
+/// is a variable width encoding, `String`s are typically smaller than an array of
+/// the same `chars`:
+///
+/// ```
+/// use std::mem;
+///
+/// // `s` is ASCII which represents each `char` as one byte
+/// let s = "hello";
+/// assert_eq!(s.len(), 5);
+///
+/// // A `char` array with the same contents would be longer because
+/// // every `char` is four bytes
+/// let s = ['h', 'e', 'l', 'l', 'o'];
+/// let size: usize = s.into_iter().map(|c| mem::size_of_val(&c)).sum();
+/// assert_eq!(size, 20);
+///
+/// // However, for non-ASCII strings, the difference will be smaller
+/// // and sometimes they are the same
+/// let s = "💖💖💖💖💖";
+/// assert_eq!(s.len(), 20);
+///
+/// let s = ['💖', '💖', '💖', '💖', '💖'];
+/// let size: usize = s.into_iter().map(|c| mem::size_of_val(&c)).sum();
+/// assert_eq!(size, 20);
+/// ```
+///
+/// This raises interesting questions as to how `s[i]` should work.
+/// What should `i` be here? Several options include byte indices and
+/// `char` indices but, because of UTF-8 encoding, only byte indices
+/// would provide constant time indexing. Getting the `i`th `char`, for
+/// example, is available using [`chars`]:
+///
+/// ```
+/// let s = "hello";
+/// let third_character = s.chars().nth(2);
+/// assert_eq!(third_character, Some('l'));
+///
+/// let s = "💖💖💖💖💖";
+/// let third_character = s.chars().nth(2);
+/// assert_eq!(third_character, Some('💖'));
+/// ```
+///
+/// Next, what should `s[i]` return? Because indexing returns a reference
+/// to underlying data it could be `&u8`, `&[u8]`, or something else similar.
+/// Since we're only providing one index, `&u8` makes the most sense but that
+/// might not be what the user expects and can be explicitly achieved with
+/// [`as_bytes()`]:
+///
+/// ```
+/// // The first byte is 104 - the byte value of `'h'`
+/// let s = "hello";
+/// assert_eq!(s.as_bytes()[0], 104);
+/// // or
+/// assert_eq!(s.as_bytes()[0], b'h');
+///
+/// // The first byte is 240 which isn't obviously useful
+/// let s = "💖💖💖💖💖";
+/// assert_eq!(s.as_bytes()[0], 240);
+/// ```
+///
+/// Due to these ambiguities/restrictions, indexing with a `usize` is simply
+/// forbidden:
+///
+/// ```compile_fail,E0277
+/// let s = "hello";
+///
+/// // The following will not compile!
+/// println!("The first letter of s is {}", s[0]);
+/// ```
+///
+/// It is more clear, however, how `&s[i..j]` should work (that is,
+/// indexing with a range). It should accept byte indices (to be constant-time)
+/// and return a `&str` which is UTF-8 encoded. This is also called "string slicing".
+/// Note this will panic if the byte indices provided are not character
+/// boundaries - see [`is_char_boundary`] for more details. See the implementations
+/// for [`SliceIndex<str>`] for more details on string slicing. For a non-panicking
+/// version of string slicing, see [`get`].
+///
+/// [`OsString`]: ../../std/ffi/struct.OsString.html "ffi::OsString"
+/// [`SliceIndex<str>`]: core::slice::SliceIndex
+/// [`as_bytes()`]: str::as_bytes
+/// [`get`]: str::get
+/// [`is_char_boundary`]: str::is_char_boundary
+///
+/// The [`bytes`] and [`chars`] methods return iterators over the bytes and
+/// codepoints of the string, respectively. To iterate over codepoints along
+/// with byte indices, use [`char_indices`].
+///
+/// [`bytes`]: str::bytes
+/// [`chars`]: str::chars
+/// [`char_indices`]: str::char_indices
+///
+/// # Deref
+///
+/// `String` implements <code>[Deref]<Target = [str]></code>, and so inherits all of [`str`]'s
+/// methods. In addition, this means that you can pass a `String` to a
+/// function which takes a [`&str`] by using an ampersand (`&`):
+///
+/// ```
+/// fn takes_str(s: &str) { }
+///
+/// let s = String::from("Hello");
+///
+/// takes_str(&s);
+/// ```
+///
+/// This will create a [`&str`] from the `String` and pass it in. This
+/// conversion is very inexpensive, and so generally, functions will accept
+/// [`&str`]s as arguments unless they need a `String` for some specific
+/// reason.
+///
+/// In certain cases Rust doesn't have enough information to make this
+/// conversion, known as [`Deref`] coercion. In the following example a string
+/// slice [`&'a str`][`&str`] implements the trait `TraitExample`, and the function
+/// `example_func` takes anything that implements the trait. In this case Rust
+/// would need to make two implicit conversions, which Rust doesn't have the
+/// means to do. For that reason, the following example will not compile.
+///
+/// ```compile_fail,E0277
+/// trait TraitExample {}
+///
+/// impl<'a> TraitExample for &'a str {}
+///
+/// fn example_func<A: TraitExample>(example_arg: A) {}
+///
+/// let example_string = String::from("example_string");
+/// example_func(&example_string);
+/// ```
+///
+/// There are two options that would work instead. The first would be to
+/// change the line `example_func(&example_string);` to
+/// `example_func(example_string.as_str());`, using the method [`as_str()`]
+/// to explicitly extract the string slice containing the string. The second
+/// way changes `example_func(&example_string);` to
+/// `example_func(&*example_string);`. In this case we are dereferencing a
+/// `String` to a [`str`], then referencing the [`str`] back to
+/// [`&str`]. The second way is more idiomatic, however both work to do the
+/// conversion explicitly rather than relying on the implicit conversion.
+///
+/// # Representation
+///
+/// A `String` is made up of three components: a pointer to some bytes, a
+/// length, and a capacity. The pointer points to an internal buffer `String`
+/// uses to store its data. The length is the number of bytes currently stored
+/// in the buffer, and the capacity is the size of the buffer in bytes. As such,
+/// the length will always be less than or equal to the capacity.
+///
+/// This buffer is always stored on the heap.
+///
+/// You can look at these with the [`as_ptr`], [`len`], and [`capacity`]
+/// methods:
+///
+/// ```
+/// use std::mem;
+///
+/// let story = String::from("Once upon a time...");
+///
+// FIXME Update this when vec_into_raw_parts is stabilized
+/// // Prevent automatically dropping the String's data
+/// let mut story = mem::ManuallyDrop::new(story);
+///
+/// let ptr = story.as_mut_ptr();
+/// let len = story.len();
+/// let capacity = story.capacity();
+///
+/// // story has nineteen bytes
+/// assert_eq!(19, len);
+///
+/// // We can re-build a String out of ptr, len, and capacity. This is all
+/// // unsafe because we are responsible for making sure the components are
+/// // valid:
+/// let s = unsafe { String::from_raw_parts(ptr, len, capacity) } ;
+///
+/// assert_eq!(String::from("Once upon a time..."), s);
+/// ```
+///
+/// [`as_ptr`]: str::as_ptr
+/// [`len`]: String::len
+/// [`capacity`]: String::capacity
+///
+/// If a `String` has enough capacity, adding elements to it will not
+/// re-allocate. For example, consider this program:
+///
+/// ```
+/// let mut s = String::new();
+///
+/// println!("{}", s.capacity());
+///
+/// for _ in 0..5 {
+///     s.push_str("hello");
+///     println!("{}", s.capacity());
+/// }
+/// ```
+///
+/// This will output the following:
+///
+/// ```text
+/// 0
+/// 5
+/// 10
+/// 20
+/// 20
+/// 40
+/// ```
+///
+/// At first, we have no memory allocated at all, but as we append to the
+/// string, it increases its capacity appropriately. If we instead use the
+/// [`with_capacity`] method to allocate the correct capacity initially:
+///
+/// ```
+/// let mut s = String::with_capacity(25);
+///
+/// println!("{}", s.capacity());
+///
+/// for _ in 0..5 {
+///     s.push_str("hello");
+///     println!("{}", s.capacity());
+/// }
+/// ```
+///
+/// [`with_capacity`]: String::with_capacity
+///
+/// We end up with a different output:
+///
+/// ```text
+/// 25
+/// 25
+/// 25
+/// 25
+/// 25
+/// 25
+/// ```
+///
+/// Here, there's no need to allocate more memory inside the loop.
+///
+/// [str]: prim@str "str"
+/// [`str`]: prim@str "str"
+/// [`&str`]: prim@str "&str"
+/// [Deref]: core::ops::Deref "ops::Deref"
+/// [`Deref`]: core::ops::Deref "ops::Deref"
+/// [`as_str()`]: String::as_str
+#[derive(PartialOrd, Eq, Ord)]
+#[cfg_attr(not(test), rustc_diagnostic_item = "String")]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub struct String {
+    vec: Vec<u8>,
+}
+
+/// A possible error value when converting a `String` from a UTF-8 byte vector.
+///
+/// This type is the error type for the [`from_utf8`] method on [`String`]. It
+/// is designed in such a way to carefully avoid reallocations: the
+/// [`into_bytes`] method will give back the byte vector that was used in the
+/// conversion attempt.
+///
+/// [`from_utf8`]: String::from_utf8
+/// [`into_bytes`]: FromUtf8Error::into_bytes
+///
+/// The [`Utf8Error`] type provided by [`std::str`] represents an error that may
+/// occur when converting a slice of [`u8`]s to a [`&str`]. In this sense, it's
+/// an analogue to `FromUtf8Error`, and you can get one from a `FromUtf8Error`
+/// through the [`utf8_error`] method.
+///
+/// [`Utf8Error`]: str::Utf8Error "std::str::Utf8Error"
+/// [`std::str`]: core::str "std::str"
+/// [`&str`]: prim@str "&str"
+/// [`utf8_error`]: FromUtf8Error::utf8_error
+///
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// // some invalid bytes, in a vector
+/// let bytes = vec![0, 159];
+///
+/// let value = String::from_utf8(bytes);
+///
+/// assert!(value.is_err());
+/// assert_eq!(vec![0, 159], value.unwrap_err().into_bytes());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(no_global_oom_handling), derive(Clone))]
+#[derive(Debug, PartialEq, Eq)]
+pub struct FromUtf8Error {
+    bytes: Vec<u8>,
+    error: Utf8Error,
+}
+
+/// A possible error value when converting a `String` from a UTF-16 byte slice.
+///
+/// This type is the error type for the [`from_utf16`] method on [`String`].
+///
+/// [`from_utf16`]: String::from_utf16
+/// # Examples
+///
+/// Basic usage:
+///
+/// ```
+/// // 𝄞mu<invalid>ic
+/// let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
+///           0xD800, 0x0069, 0x0063];
+///
+/// assert!(String::from_utf16(v).is_err());
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[derive(Debug)]
+pub struct FromUtf16Error(());
+
+impl String {
+    /// Creates a new empty `String`.
+    ///
+    /// Given that the `String` is empty, this will not allocate any initial
+    /// buffer. While that means that this initial operation is very
+    /// inexpensive, it may cause excessive allocation later when you add
+    /// data. If you have an idea of how much data the `String` will hold,
+    /// consider the [`with_capacity`] method to prevent excessive
+    /// re-allocation.
+    ///
+    /// [`with_capacity`]: String::with_capacity
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = String::new();
+    /// ```
+    #[inline]
+    #[rustc_const_stable(feature = "const_string_new", since = "1.39.0")]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use]
+    pub const fn new() -> String {
+        String { vec: Vec::new() }
+    }
+
+    /// Creates a new empty `String` with a particular capacity.
+    ///
+    /// `String`s have an internal buffer to hold their data. The capacity is
+    /// the length of that buffer, and can be queried with the [`capacity`]
+    /// method. This method creates an empty `String`, but one with an initial
+    /// buffer that can hold `capacity` bytes. This is useful when you may be
+    /// appending a bunch of data to the `String`, reducing the number of
+    /// reallocations it needs to do.
+    ///
+    /// [`capacity`]: String::capacity
+    ///
+    /// If the given capacity is `0`, no allocation will occur, and this method
+    /// is identical to the [`new`] method.
+    ///
+    /// [`new`]: String::new
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::with_capacity(10);
+    ///
+    /// // The String contains no chars, even though it has capacity for more
+    /// assert_eq!(s.len(), 0);
+    ///
+    /// // These are all done without reallocating...
+    /// let cap = s.capacity();
+    /// for _ in 0..10 {
+    ///     s.push('a');
+    /// }
+    ///
+    /// assert_eq!(s.capacity(), cap);
+    ///
+    /// // ...but this may make the string reallocate
+    /// s.push('a');
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use]
+    pub fn with_capacity(capacity: usize) -> String {
+        String { vec: Vec::with_capacity(capacity) }
+    }
+
+    // HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is
+    // required for this method definition, is not available. Since we don't
+    // require this method for testing purposes, I'll just stub it
+    // NB see the slice::hack module in slice.rs for more information
+    #[inline]
+    #[cfg(test)]
+    pub fn from_str(_: &str) -> String {
+        panic!("not available with cfg(test)");
+    }
+
+    /// Converts a vector of bytes to a `String`.
+    ///
+    /// A string ([`String`]) is made of bytes ([`u8`]), and a vector of bytes
+    /// ([`Vec<u8>`]) is made of bytes, so this function converts between the
+    /// two. Not all byte slices are valid `String`s, however: `String`
+    /// requires that it is valid UTF-8. `from_utf8()` checks to ensure that
+    /// the bytes are valid UTF-8, and then does the conversion.
+    ///
+    /// If you are sure that the byte slice is valid UTF-8, and you don't want
+    /// to incur the overhead of the validity check, there is an unsafe version
+    /// of this function, [`from_utf8_unchecked`], which has the same behavior
+    /// but skips the check.
+    ///
+    /// This method will take care to not copy the vector, for efficiency's
+    /// sake.
+    ///
+    /// If you need a [`&str`] instead of a `String`, consider
+    /// [`str::from_utf8`].
+    ///
+    /// The inverse of this method is [`into_bytes`].
+    ///
+    /// # Errors
+    ///
+    /// Returns [`Err`] if the slice is not UTF-8 with a description as to why the
+    /// provided bytes are not UTF-8. The vector you moved in is also included.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // some bytes, in a vector
+    /// let sparkle_heart = vec![240, 159, 146, 150];
+    ///
+    /// // We know these bytes are valid, so we'll use `unwrap()`.
+    /// let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();
+    ///
+    /// assert_eq!("💖", sparkle_heart);
+    /// ```
+    ///
+    /// Incorrect bytes:
+    ///
+    /// ```
+    /// // some invalid bytes, in a vector
+    /// let sparkle_heart = vec![0, 159, 146, 150];
+    ///
+    /// assert!(String::from_utf8(sparkle_heart).is_err());
+    /// ```
+    ///
+    /// See the docs for [`FromUtf8Error`] for more details on what you can do
+    /// with this error.
+    ///
+    /// [`from_utf8_unchecked`]: String::from_utf8_unchecked
+    /// [`Vec<u8>`]: crate::vec::Vec "Vec"
+    /// [`&str`]: prim@str "&str"
+    /// [`into_bytes`]: String::into_bytes
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_utf8(vec: Vec<u8>) -> Result<String, FromUtf8Error> {
+        match str::from_utf8(&vec) {
+            Ok(..) => Ok(String { vec }),
+            Err(e) => Err(FromUtf8Error { bytes: vec, error: e }),
+        }
+    }
+
+    /// Converts a slice of bytes to a string, including invalid characters.
+    ///
+    /// Strings are made of bytes ([`u8`]), and a slice of bytes
+    /// ([`&[u8]`][byteslice]) is made of bytes, so this function converts
+    /// between the two. Not all byte slices are valid strings, however: strings
+    /// are required to be valid UTF-8. During this conversion,
+    /// `from_utf8_lossy()` will replace any invalid UTF-8 sequences with
+    /// [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD], which looks like this: �
+    ///
+    /// [byteslice]: prim@slice
+    /// [U+FFFD]: core::char::REPLACEMENT_CHARACTER
+    ///
+    /// If you are sure that the byte slice is valid UTF-8, and you don't want
+    /// to incur the overhead of the conversion, there is an unsafe version
+    /// of this function, [`from_utf8_unchecked`], which has the same behavior
+    /// but skips the checks.
+    ///
+    /// [`from_utf8_unchecked`]: String::from_utf8_unchecked
+    ///
+    /// This function returns a [`Cow<'a, str>`]. If our byte slice is invalid
+    /// UTF-8, then we need to insert the replacement characters, which will
+    /// change the size of the string, and hence, require a `String`. But if
+    /// it's already valid UTF-8, we don't need a new allocation. This return
+    /// type allows us to handle both cases.
+    ///
+    /// [`Cow<'a, str>`]: crate::borrow::Cow "borrow::Cow"
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // some bytes, in a vector
+    /// let sparkle_heart = vec![240, 159, 146, 150];
+    ///
+    /// let sparkle_heart = String::from_utf8_lossy(&sparkle_heart);
+    ///
+    /// assert_eq!("💖", sparkle_heart);
+    /// ```
+    ///
+    /// Incorrect bytes:
+    ///
+    /// ```
+    /// // some invalid bytes
+    /// let input = b"Hello \xF0\x90\x80World";
+    /// let output = String::from_utf8_lossy(input);
+    ///
+    /// assert_eq!("Hello �World", output);
+    /// ```
+    #[must_use]
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_utf8_lossy(v: &[u8]) -> Cow<'_, str> {
+        let mut iter = lossy::Utf8Lossy::from_bytes(v).chunks();
+
+        let first_valid = if let Some(chunk) = iter.next() {
+            let lossy::Utf8LossyChunk { valid, broken } = chunk;
+            if broken.is_empty() {
+                debug_assert_eq!(valid.len(), v.len());
+                return Cow::Borrowed(valid);
+            }
+            valid
+        } else {
+            return Cow::Borrowed("");
+        };
+
+        const REPLACEMENT: &str = "\u{FFFD}";
+
+        let mut res = String::with_capacity(v.len());
+        res.push_str(first_valid);
+        res.push_str(REPLACEMENT);
+
+        for lossy::Utf8LossyChunk { valid, broken } in iter {
+            res.push_str(valid);
+            if !broken.is_empty() {
+                res.push_str(REPLACEMENT);
+            }
+        }
+
+        Cow::Owned(res)
+    }
+
+    /// Decode a UTF-16–encoded vector `v` into a `String`, returning [`Err`]
+    /// if `v` contains any invalid data.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // 𝄞music
+    /// let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
+    ///           0x0073, 0x0069, 0x0063];
+    /// assert_eq!(String::from("𝄞music"),
+    ///            String::from_utf16(v).unwrap());
+    ///
+    /// // 𝄞mu<invalid>ic
+    /// let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
+    ///           0xD800, 0x0069, 0x0063];
+    /// assert!(String::from_utf16(v).is_err());
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_utf16(v: &[u16]) -> Result<String, FromUtf16Error> {
+        // This isn't done via collect::<Result<_, _>>() for performance reasons.
+        // FIXME: the function can be simplified again when #48994 is closed.
+        let mut ret = String::with_capacity(v.len());
+        for c in decode_utf16(v.iter().cloned()) {
+            if let Ok(c) = c {
+                ret.push(c);
+            } else {
+                return Err(FromUtf16Error(()));
+            }
+        }
+        Ok(ret)
+    }
+
+    /// Decode a UTF-16–encoded slice `v` into a `String`, replacing
+    /// invalid data with [the replacement character (`U+FFFD`)][U+FFFD].
+    ///
+    /// Unlike [`from_utf8_lossy`] which returns a [`Cow<'a, str>`],
+    /// `from_utf16_lossy` returns a `String` since the UTF-16 to UTF-8
+    /// conversion requires a memory allocation.
+    ///
+    /// [`from_utf8_lossy`]: String::from_utf8_lossy
+    /// [`Cow<'a, str>`]: crate::borrow::Cow "borrow::Cow"
+    /// [U+FFFD]: core::char::REPLACEMENT_CHARACTER
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // 𝄞mus<invalid>ic<invalid>
+    /// let v = &[0xD834, 0xDD1E, 0x006d, 0x0075,
+    ///           0x0073, 0xDD1E, 0x0069, 0x0063,
+    ///           0xD834];
+    ///
+    /// assert_eq!(String::from("𝄞mus\u{FFFD}ic\u{FFFD}"),
+    ///            String::from_utf16_lossy(v));
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[must_use]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn from_utf16_lossy(v: &[u16]) -> String {
+        decode_utf16(v.iter().cloned()).map(|r| r.unwrap_or(REPLACEMENT_CHARACTER)).collect()
+    }
+
+    /// Decomposes a `String` into its raw components.
+    ///
+    /// Returns the raw pointer to the underlying data, the length of
+    /// the string (in bytes), and the allocated capacity of the data
+    /// (in bytes). These are the same arguments in the same order as
+    /// the arguments to [`from_raw_parts`].
+    ///
+    /// After calling this function, the caller is responsible for the
+    /// memory previously managed by the `String`. The only way to do
+    /// this is to convert the raw pointer, length, and capacity back
+    /// into a `String` with the [`from_raw_parts`] function, allowing
+    /// the destructor to perform the cleanup.
+    ///
+    /// [`from_raw_parts`]: String::from_raw_parts
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(vec_into_raw_parts)]
+    /// let s = String::from("hello");
+    ///
+    /// let (ptr, len, cap) = s.into_raw_parts();
+    ///
+    /// let rebuilt = unsafe { String::from_raw_parts(ptr, len, cap) };
+    /// assert_eq!(rebuilt, "hello");
+    /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
+    pub fn into_raw_parts(self) -> (*mut u8, usize, usize) {
+        self.vec.into_raw_parts()
+    }
+
+    /// Creates a new `String` from a length, capacity, and pointer.
+    ///
+    /// # Safety
+    ///
+    /// This is highly unsafe, due to the number of invariants that aren't
+    /// checked:
+    ///
+    /// * The memory at `buf` needs to have been previously allocated by the
+    ///   same allocator the standard library uses, with a required alignment of exactly 1.
+    /// * `length` needs to be less than or equal to `capacity`.
+    /// * `capacity` needs to be the correct value.
+    /// * The first `length` bytes at `buf` need to be valid UTF-8.
+    ///
+    /// Violating these may cause problems like corrupting the allocator's
+    /// internal data structures. For example, it is normally **not** safe to
+    /// build a `String` from a pointer to a C `char` array containing UTF-8
+    /// _unless_ you are certain that array was originally allocated by the
+    /// Rust standard library's allocator.
+    ///
+    /// The ownership of `buf` is effectively transferred to the
+    /// `String` which may then deallocate, reallocate or change the
+    /// contents of memory pointed to by the pointer at will. Ensure
+    /// that nothing else uses the pointer after calling this
+    /// function.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// use std::mem;
+    ///
+    /// unsafe {
+    ///     let s = String::from("hello");
+    ///
+    // FIXME Update this when vec_into_raw_parts is stabilized
+    ///     // Prevent automatically dropping the String's data
+    ///     let mut s = mem::ManuallyDrop::new(s);
+    ///
+    ///     let ptr = s.as_mut_ptr();
+    ///     let len = s.len();
+    ///     let capacity = s.capacity();
+    ///
+    ///     let s = String::from_raw_parts(ptr, len, capacity);
+    ///
+    ///     assert_eq!(String::from("hello"), s);
+    /// }
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub unsafe fn from_raw_parts(buf: *mut u8, length: usize, capacity: usize) -> String {
+        unsafe { String { vec: Vec::from_raw_parts(buf, length, capacity) } }
+    }
+
+    /// Converts a vector of bytes to a `String` without checking that the
+    /// string contains valid UTF-8.
+    ///
+    /// See the safe version, [`from_utf8`], for more details.
+    ///
+    /// [`from_utf8`]: String::from_utf8
+    ///
+    /// # Safety
+    ///
+    /// This function is unsafe because it does not check that the bytes passed
+    /// to it are valid UTF-8. If this constraint is violated, it may cause
+    /// memory unsafety issues with future users of the `String`, as the rest of
+    /// the standard library assumes that `String`s are valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // some bytes, in a vector
+    /// let sparkle_heart = vec![240, 159, 146, 150];
+    ///
+    /// let sparkle_heart = unsafe {
+    ///     String::from_utf8_unchecked(sparkle_heart)
+    /// };
+    ///
+    /// assert_eq!("💖", sparkle_heart);
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub unsafe fn from_utf8_unchecked(bytes: Vec<u8>) -> String {
+        String { vec: bytes }
+    }
+
+    /// Converts a `String` into a byte vector.
+    ///
+    /// This consumes the `String`, so we do not need to copy its contents.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = String::from("hello");
+    /// let bytes = s.into_bytes();
+    ///
+    /// assert_eq!(&[104, 101, 108, 108, 111][..], &bytes[..]);
+    /// ```
+    #[inline]
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_bytes(self) -> Vec<u8> {
+        self.vec
+    }
+
+    /// Extracts a string slice containing the entire `String`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = String::from("foo");
+    ///
+    /// assert_eq!("foo", s.as_str());
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "string_as_str", since = "1.7.0")]
+    pub fn as_str(&self) -> &str {
+        self
+    }
+
+    /// Converts a `String` into a mutable string slice.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("foobar");
+    /// let s_mut_str = s.as_mut_str();
+    ///
+    /// s_mut_str.make_ascii_uppercase();
+    ///
+    /// assert_eq!("FOOBAR", s_mut_str);
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "string_as_str", since = "1.7.0")]
+    pub fn as_mut_str(&mut self) -> &mut str {
+        self
+    }
+
+    /// Appends a given string slice onto the end of this `String`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("foo");
+    ///
+    /// s.push_str("bar");
+    ///
+    /// assert_eq!("foobar", s);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn push_str(&mut self, string: &str) {
+        self.vec.extend_from_slice(string.as_bytes())
+    }
+
+    /// Copies elements from `src` range to the end of the string.
+    ///
+    /// ## Panics
+    ///
+    /// Panics if the starting point or end point do not lie on a [`char`]
+    /// boundary, or if they're out of bounds.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// #![feature(string_extend_from_within)]
+    /// let mut string = String::from("abcde");
+    ///
+    /// string.extend_from_within(2..);
+    /// assert_eq!(string, "abcdecde");
+    ///
+    /// string.extend_from_within(..2);
+    /// assert_eq!(string, "abcdecdeab");
+    ///
+    /// string.extend_from_within(4..8);
+    /// assert_eq!(string, "abcdecdeabecde");
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "string_extend_from_within", issue = "none")]
+    pub fn extend_from_within<R>(&mut self, src: R)
+    where
+        R: RangeBounds<usize>,
+    {
+        let src @ Range { start, end } = slice::range(src, ..self.len());
+
+        assert!(self.is_char_boundary(start));
+        assert!(self.is_char_boundary(end));
+
+        self.vec.extend_from_within(src);
+    }
+
+    /// Returns this `String`'s capacity, in bytes.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = String::with_capacity(10);
+    ///
+    /// assert!(s.capacity() >= 10);
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn capacity(&self) -> usize {
+        self.vec.capacity()
+    }
+
+    /// Ensures that this `String`'s capacity is at least `additional` bytes
+    /// larger than its length.
+    ///
+    /// The capacity may be increased by more than `additional` bytes if it
+    /// chooses, to prevent frequent reallocations.
+    ///
+    /// If you do not want this "at least" behavior, see the [`reserve_exact`]
+    /// method.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity overflows [`usize`].
+    ///
+    /// [`reserve_exact`]: String::reserve_exact
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::new();
+    ///
+    /// s.reserve(10);
+    ///
+    /// assert!(s.capacity() >= 10);
+    /// ```
+    ///
+    /// This might not actually increase the capacity:
+    ///
+    /// ```
+    /// let mut s = String::with_capacity(10);
+    /// s.push('a');
+    /// s.push('b');
+    ///
+    /// // s now has a length of 2 and a capacity of 10
+    /// assert_eq!(2, s.len());
+    /// assert_eq!(10, s.capacity());
+    ///
+    /// // Since we already have an extra 8 capacity, calling this...
+    /// s.reserve(8);
+    ///
+    /// // ... doesn't actually increase.
+    /// assert_eq!(10, s.capacity());
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn reserve(&mut self, additional: usize) {
+        self.vec.reserve(additional)
+    }
+
+    /// Ensures that this `String`'s capacity is `additional` bytes
+    /// larger than its length.
+    ///
+    /// Consider using the [`reserve`] method unless you absolutely know
+    /// better than the allocator.
+    ///
+    /// [`reserve`]: String::reserve
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity overflows `usize`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::new();
+    ///
+    /// s.reserve_exact(10);
+    ///
+    /// assert!(s.capacity() >= 10);
+    /// ```
+    ///
+    /// This might not actually increase the capacity:
+    ///
+    /// ```
+    /// let mut s = String::with_capacity(10);
+    /// s.push('a');
+    /// s.push('b');
+    ///
+    /// // s now has a length of 2 and a capacity of 10
+    /// assert_eq!(2, s.len());
+    /// assert_eq!(10, s.capacity());
+    ///
+    /// // Since we already have an extra 8 capacity, calling this...
+    /// s.reserve_exact(8);
+    ///
+    /// // ... doesn't actually increase.
+    /// assert_eq!(10, s.capacity());
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn reserve_exact(&mut self, additional: usize) {
+        self.vec.reserve_exact(additional)
+    }
+
+    /// Tries to reserve capacity for at least `additional` more elements to be inserted
+    /// in the given `String`. The collection may reserve more space to avoid
+    /// frequent reallocations. After calling `reserve`, capacity will be
+    /// greater than or equal to `self.len() + additional`. Does nothing if
+    /// capacity is already sufficient.
+    ///
+    /// # Errors
+    ///
+    /// If the capacity overflows, or the allocator reports a failure, then an error
+    /// is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::collections::TryReserveError;
+    ///
+    /// fn process_data(data: &str) -> Result<String, TryReserveError> {
+    ///     let mut output = String::new();
+    ///
+    ///     // Pre-reserve the memory, exiting if we can't
+    ///     output.try_reserve(data.len())?;
+    ///
+    ///     // Now we know this can't OOM in the middle of our complex work
+    ///     output.push_str(data);
+    ///
+    ///     Ok(output)
+    /// }
+    /// # process_data("rust").expect("why is the test harness OOMing on 4 bytes?");
+    /// ```
+    #[stable(feature = "try_reserve", since = "1.57.0")]
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
+        self.vec.try_reserve(additional)
+    }
+
+    /// Tries to reserve the minimum capacity for exactly `additional` more elements to
+    /// be inserted in the given `String`. After calling `try_reserve_exact`,
+    /// capacity will be greater than or equal to `self.len() + additional`.
+    /// Does nothing if the capacity is already sufficient.
+    ///
+    /// Note that the allocator may give the collection more space than it
+    /// requests. Therefore, capacity can not be relied upon to be precisely
+    /// minimal. Prefer [`try_reserve`] if future insertions are expected.
+    ///
+    /// [`try_reserve`]: String::try_reserve
+    ///
+    /// # Errors
+    ///
+    /// If the capacity overflows, or the allocator reports a failure, then an error
+    /// is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::collections::TryReserveError;
+    ///
+    /// fn process_data(data: &str) -> Result<String, TryReserveError> {
+    ///     let mut output = String::new();
+    ///
+    ///     // Pre-reserve the memory, exiting if we can't
+    ///     output.try_reserve_exact(data.len())?;
+    ///
+    ///     // Now we know this can't OOM in the middle of our complex work
+    ///     output.push_str(data);
+    ///
+    ///     Ok(output)
+    /// }
+    /// # process_data("rust").expect("why is the test harness OOMing on 4 bytes?");
+    /// ```
+    #[stable(feature = "try_reserve", since = "1.57.0")]
+    pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> {
+        self.vec.try_reserve_exact(additional)
+    }
+
+    /// Shrinks the capacity of this `String` to match its length.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("foo");
+    ///
+    /// s.reserve(100);
+    /// assert!(s.capacity() >= 100);
+    ///
+    /// s.shrink_to_fit();
+    /// assert_eq!(3, s.capacity());
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn shrink_to_fit(&mut self) {
+        self.vec.shrink_to_fit()
+    }
+
+    /// Shrinks the capacity of this `String` with a lower bound.
+    ///
+    /// The capacity will remain at least as large as both the length
+    /// and the supplied value.
+    ///
+    /// If the current capacity is less than the lower limit, this is a no-op.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut s = String::from("foo");
+    ///
+    /// s.reserve(100);
+    /// assert!(s.capacity() >= 100);
+    ///
+    /// s.shrink_to(10);
+    /// assert!(s.capacity() >= 10);
+    /// s.shrink_to(0);
+    /// assert!(s.capacity() >= 3);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "shrink_to", since = "1.56.0")]
+    pub fn shrink_to(&mut self, min_capacity: usize) {
+        self.vec.shrink_to(min_capacity)
+    }
+
+    /// Appends the given [`char`] to the end of this `String`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("abc");
+    ///
+    /// s.push('1');
+    /// s.push('2');
+    /// s.push('3');
+    ///
+    /// assert_eq!("abc123", s);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn push(&mut self, ch: char) {
+        match ch.len_utf8() {
+            1 => self.vec.push(ch as u8),
+            _ => self.vec.extend_from_slice(ch.encode_utf8(&mut [0; 4]).as_bytes()),
+        }
+    }
+
+    /// Returns a byte slice of this `String`'s contents.
+    ///
+    /// The inverse of this method is [`from_utf8`].
+    ///
+    /// [`from_utf8`]: String::from_utf8
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = String::from("hello");
+    ///
+    /// assert_eq!(&[104, 101, 108, 108, 111], s.as_bytes());
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn as_bytes(&self) -> &[u8] {
+        &self.vec
+    }
+
+    /// Shortens this `String` to the specified length.
+    ///
+    /// If `new_len` is greater than the string's current length, this has no
+    /// effect.
+    ///
+    /// Note that this method has no effect on the allocated capacity
+    /// of the string
+    ///
+    /// # Panics
+    ///
+    /// Panics if `new_len` does not lie on a [`char`] boundary.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("hello");
+    ///
+    /// s.truncate(2);
+    ///
+    /// assert_eq!("he", s);
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn truncate(&mut self, new_len: usize) {
+        if new_len <= self.len() {
+            assert!(self.is_char_boundary(new_len));
+            self.vec.truncate(new_len)
+        }
+    }
+
+    /// Removes the last character from the string buffer and returns it.
+    ///
+    /// Returns [`None`] if this `String` is empty.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("foo");
+    ///
+    /// assert_eq!(s.pop(), Some('o'));
+    /// assert_eq!(s.pop(), Some('o'));
+    /// assert_eq!(s.pop(), Some('f'));
+    ///
+    /// assert_eq!(s.pop(), None);
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn pop(&mut self) -> Option<char> {
+        let ch = self.chars().rev().next()?;
+        let newlen = self.len() - ch.len_utf8();
+        unsafe {
+            self.vec.set_len(newlen);
+        }
+        Some(ch)
+    }
+
+    /// Removes a [`char`] from this `String` at a byte position and returns it.
+    ///
+    /// This is an *O*(*n*) operation, as it requires copying every element in the
+    /// buffer.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `idx` is larger than or equal to the `String`'s length,
+    /// or if it does not lie on a [`char`] boundary.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("foo");
+    ///
+    /// assert_eq!(s.remove(0), 'f');
+    /// assert_eq!(s.remove(1), 'o');
+    /// assert_eq!(s.remove(0), 'o');
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn remove(&mut self, idx: usize) -> char {
+        let ch = match self[idx..].chars().next() {
+            Some(ch) => ch,
+            None => panic!("cannot remove a char from the end of a string"),
+        };
+
+        let next = idx + ch.len_utf8();
+        let len = self.len();
+        unsafe {
+            ptr::copy(self.vec.as_ptr().add(next), self.vec.as_mut_ptr().add(idx), len - next);
+            self.vec.set_len(len - (next - idx));
+        }
+        ch
+    }
+
+    /// Remove all matches of pattern `pat` in the `String`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(string_remove_matches)]
+    /// let mut s = String::from("Trees are not green, the sky is not blue.");
+    /// s.remove_matches("not ");
+    /// assert_eq!("Trees are green, the sky is blue.", s);
+    /// ```
+    ///
+    /// Matches will be detected and removed iteratively, so in cases where
+    /// patterns overlap, only the first pattern will be removed:
+    ///
+    /// ```
+    /// #![feature(string_remove_matches)]
+    /// let mut s = String::from("banana");
+    /// s.remove_matches("ana");
+    /// assert_eq!("bna", s);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[unstable(feature = "string_remove_matches", reason = "new API", issue = "72826")]
+    pub fn remove_matches<'a, P>(&'a mut self, pat: P)
+    where
+        P: for<'x> Pattern<'x>,
+    {
+        use core::str::pattern::Searcher;
+
+        let rejections = {
+            let mut searcher = pat.into_searcher(self);
+            // Per Searcher::next:
+            //
+            // A Match result needs to contain the whole matched pattern,
+            // however Reject results may be split up into arbitrary many
+            // adjacent fragments. Both ranges may have zero length.
+            //
+            // In practice the implementation of Searcher::next_match tends to
+            // be more efficient, so we use it here and do some work to invert
+            // matches into rejections since that's what we want to copy below.
+            let mut front = 0;
+            let rejections: Vec<_> = from_fn(|| {
+                let (start, end) = searcher.next_match()?;
+                let prev_front = front;
+                front = end;
+                Some((prev_front, start))
+            })
+            .collect();
+            rejections.into_iter().chain(core::iter::once((front, self.len())))
+        };
+
+        let mut len = 0;
+        let ptr = self.vec.as_mut_ptr();
+
+        for (start, end) in rejections {
+            let count = end - start;
+            if start != len {
+                // SAFETY: per Searcher::next:
+                //
+                // The stream of Match and Reject values up to a Done will
+                // contain index ranges that are adjacent, non-overlapping,
+                // covering the whole haystack, and laying on utf8
+                // boundaries.
+                unsafe {
+                    ptr::copy(ptr.add(start), ptr.add(len), count);
+                }
+            }
+            len += count;
+        }
+
+        unsafe {
+            self.vec.set_len(len);
+        }
+    }
+
+    /// Retains only the characters specified by the predicate.
+    ///
+    /// In other words, remove all characters `c` such that `f(c)` returns `false`.
+    /// This method operates in place, visiting each character exactly once in the
+    /// original order, and preserves the order of the retained characters.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut s = String::from("f_o_ob_ar");
+    ///
+    /// s.retain(|c| c != '_');
+    ///
+    /// assert_eq!(s, "foobar");
+    /// ```
+    ///
+    /// Because the elements are visited exactly once in the original order,
+    /// external state may be used to decide which elements to keep.
+    ///
+    /// ```
+    /// let mut s = String::from("abcde");
+    /// let keep = [false, true, true, false, true];
+    /// let mut iter = keep.iter();
+    /// s.retain(|_| *iter.next().unwrap());
+    /// assert_eq!(s, "bce");
+    /// ```
+    #[inline]
+    #[stable(feature = "string_retain", since = "1.26.0")]
+    pub fn retain<F>(&mut self, mut f: F)
+    where
+        F: FnMut(char) -> bool,
+    {
+        struct SetLenOnDrop<'a> {
+            s: &'a mut String,
+            idx: usize,
+            del_bytes: usize,
+        }
+
+        impl<'a> Drop for SetLenOnDrop<'a> {
+            fn drop(&mut self) {
+                let new_len = self.idx - self.del_bytes;
+                debug_assert!(new_len <= self.s.len());
+                unsafe { self.s.vec.set_len(new_len) };
+            }
+        }
+
+        let len = self.len();
+        let mut guard = SetLenOnDrop { s: self, idx: 0, del_bytes: 0 };
+
+        while guard.idx < len {
+            let ch = unsafe { guard.s.get_unchecked(guard.idx..len).chars().next().unwrap() };
+            let ch_len = ch.len_utf8();
+
+            if !f(ch) {
+                guard.del_bytes += ch_len;
+            } else if guard.del_bytes > 0 {
+                unsafe {
+                    ptr::copy(
+                        guard.s.vec.as_ptr().add(guard.idx),
+                        guard.s.vec.as_mut_ptr().add(guard.idx - guard.del_bytes),
+                        ch_len,
+                    );
+                }
+            }
+
+            // Point idx to the next char
+            guard.idx += ch_len;
+        }
+
+        drop(guard);
+    }
+
+    /// Inserts a character into this `String` at a byte position.
+    ///
+    /// This is an *O*(*n*) operation as it requires copying every element in the
+    /// buffer.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `idx` is larger than the `String`'s length, or if it does not
+    /// lie on a [`char`] boundary.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::with_capacity(3);
+    ///
+    /// s.insert(0, 'f');
+    /// s.insert(1, 'o');
+    /// s.insert(2, 'o');
+    ///
+    /// assert_eq!("foo", s);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn insert(&mut self, idx: usize, ch: char) {
+        assert!(self.is_char_boundary(idx));
+        let mut bits = [0; 4];
+        let bits = ch.encode_utf8(&mut bits).as_bytes();
+
+        unsafe {
+            self.insert_bytes(idx, bits);
+        }
+    }
+
+    #[cfg(not(no_global_oom_handling))]
+    unsafe fn insert_bytes(&mut self, idx: usize, bytes: &[u8]) {
+        let len = self.len();
+        let amt = bytes.len();
+        self.vec.reserve(amt);
+
+        unsafe {
+            ptr::copy(self.vec.as_ptr().add(idx), self.vec.as_mut_ptr().add(idx + amt), len - idx);
+            ptr::copy_nonoverlapping(bytes.as_ptr(), self.vec.as_mut_ptr().add(idx), amt);
+            self.vec.set_len(len + amt);
+        }
+    }
+
+    /// Inserts a string slice into this `String` at a byte position.
+    ///
+    /// This is an *O*(*n*) operation as it requires copying every element in the
+    /// buffer.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `idx` is larger than the `String`'s length, or if it does not
+    /// lie on a [`char`] boundary.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("bar");
+    ///
+    /// s.insert_str(0, "foo");
+    ///
+    /// assert_eq!("foobar", s);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "insert_str", since = "1.16.0")]
+    pub fn insert_str(&mut self, idx: usize, string: &str) {
+        assert!(self.is_char_boundary(idx));
+
+        unsafe {
+            self.insert_bytes(idx, string.as_bytes());
+        }
+    }
+
+    /// Returns a mutable reference to the contents of this `String`.
+    ///
+    /// # Safety
+    ///
+    /// This function is unsafe because the returned `&mut Vec` allows writing
+    /// bytes which are not valid UTF-8. If this constraint is violated, using
+    /// the original `String` after dropping the `&mut Vec` may violate memory
+    /// safety, as the rest of the standard library assumes that `String`s are
+    /// valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("hello");
+    ///
+    /// unsafe {
+    ///     let vec = s.as_mut_vec();
+    ///     assert_eq!(&[104, 101, 108, 108, 111][..], &vec[..]);
+    ///
+    ///     vec.reverse();
+    /// }
+    /// assert_eq!(s, "olleh");
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub unsafe fn as_mut_vec(&mut self) -> &mut Vec<u8> {
+        &mut self.vec
+    }
+
+    /// Returns the length of this `String`, in bytes, not [`char`]s or
+    /// graphemes. In other words, it might not be what a human considers the
+    /// length of the string.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let a = String::from("foo");
+    /// assert_eq!(a.len(), 3);
+    ///
+    /// let fancy_f = String::from("ƒoo");
+    /// assert_eq!(fancy_f.len(), 4);
+    /// assert_eq!(fancy_f.chars().count(), 3);
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn len(&self) -> usize {
+        self.vec.len()
+    }
+
+    /// Returns `true` if this `String` has a length of zero, and `false` otherwise.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut v = String::new();
+    /// assert!(v.is_empty());
+    ///
+    /// v.push('a');
+    /// assert!(!v.is_empty());
+    /// ```
+    #[inline]
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    /// Splits the string into two at the given byte index.
+    ///
+    /// Returns a newly allocated `String`. `self` contains bytes `[0, at)`, and
+    /// the returned `String` contains bytes `[at, len)`. `at` must be on the
+    /// boundary of a UTF-8 code point.
+    ///
+    /// Note that the capacity of `self` does not change.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `at` is not on a `UTF-8` code point boundary, or if it is beyond the last
+    /// code point of the string.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # fn main() {
+    /// let mut hello = String::from("Hello, World!");
+    /// let world = hello.split_off(7);
+    /// assert_eq!(hello, "Hello, ");
+    /// assert_eq!(world, "World!");
+    /// # }
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "string_split_off", since = "1.16.0")]
+    #[must_use = "use `.truncate()` if you don't need the other half"]
+    pub fn split_off(&mut self, at: usize) -> String {
+        assert!(self.is_char_boundary(at));
+        let other = self.vec.split_off(at);
+        unsafe { String::from_utf8_unchecked(other) }
+    }
+
+    /// Truncates this `String`, removing all contents.
+    ///
+    /// While this means the `String` will have a length of zero, it does not
+    /// touch its capacity.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("foo");
+    ///
+    /// s.clear();
+    ///
+    /// assert!(s.is_empty());
+    /// assert_eq!(0, s.len());
+    /// assert_eq!(3, s.capacity());
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn clear(&mut self) {
+        self.vec.clear()
+    }
+
+    /// Removes the specified range from the string in bulk, returning all
+    /// removed characters as an iterator.
+    ///
+    /// The returned iterator keeps a mutable borrow on the string to optimize
+    /// its implementation.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the starting point or end point do not lie on a [`char`]
+    /// boundary, or if they're out of bounds.
+    ///
+    /// # Leaking
+    ///
+    /// If the returned iterator goes out of scope without being dropped (due to
+    /// [`core::mem::forget`], for example), the string may still contain a copy
+    /// of any drained characters, or may have lost characters arbitrarily,
+    /// including characters outside the range.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("α is alpha, β is beta");
+    /// let beta_offset = s.find('β').unwrap_or(s.len());
+    ///
+    /// // Remove the range up until the β from the string
+    /// let t: String = s.drain(..beta_offset).collect();
+    /// assert_eq!(t, "α is alpha, ");
+    /// assert_eq!(s, "β is beta");
+    ///
+    /// // A full range clears the string, like `clear()` does
+    /// s.drain(..);
+    /// assert_eq!(s, "");
+    /// ```
+    #[stable(feature = "drain", since = "1.6.0")]
+    pub fn drain<R>(&mut self, range: R) -> Drain<'_>
+    where
+        R: RangeBounds<usize>,
+    {
+        // Memory safety
+        //
+        // The String version of Drain does not have the memory safety issues
+        // of the vector version. The data is just plain bytes.
+        // Because the range removal happens in Drop, if the Drain iterator is leaked,
+        // the removal will not happen.
+        let Range { start, end } = slice::range(range, ..self.len());
+        assert!(self.is_char_boundary(start));
+        assert!(self.is_char_boundary(end));
+
+        // Take out two simultaneous borrows. The &mut String won't be accessed
+        // until iteration is over, in Drop.
+        let self_ptr = self as *mut _;
+        // SAFETY: `slice::range` and `is_char_boundary` do the appropriate bounds checks.
+        let chars_iter = unsafe { self.get_unchecked(start..end) }.chars();
+
+        Drain { start, end, iter: chars_iter, string: self_ptr }
+    }
+
+    /// Removes the specified range in the string,
+    /// and replaces it with the given string.
+    /// The given string doesn't need to be the same length as the range.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the starting point or end point do not lie on a [`char`]
+    /// boundary, or if they're out of bounds.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let mut s = String::from("α is alpha, β is beta");
+    /// let beta_offset = s.find('β').unwrap_or(s.len());
+    ///
+    /// // Replace the range up until the β from the string
+    /// s.replace_range(..beta_offset, "Α is capital alpha; ");
+    /// assert_eq!(s, "Α is capital alpha; β is beta");
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "splice", since = "1.27.0")]
+    pub fn replace_range<R>(&mut self, range: R, replace_with: &str)
+    where
+        R: RangeBounds<usize>,
+    {
+        // Memory safety
+        //
+        // Replace_range does not have the memory safety issues of a vector Splice.
+        // of the vector version. The data is just plain bytes.
+
+        // WARNING: Inlining this variable would be unsound (#81138)
+        let start = range.start_bound();
+        match start {
+            Included(&n) => assert!(self.is_char_boundary(n)),
+            Excluded(&n) => assert!(self.is_char_boundary(n + 1)),
+            Unbounded => {}
+        };
+        // WARNING: Inlining this variable would be unsound (#81138)
+        let end = range.end_bound();
+        match end {
+            Included(&n) => assert!(self.is_char_boundary(n + 1)),
+            Excluded(&n) => assert!(self.is_char_boundary(n)),
+            Unbounded => {}
+        };
+
+        // Using `range` again would be unsound (#81138)
+        // We assume the bounds reported by `range` remain the same, but
+        // an adversarial implementation could change between calls
+        unsafe { self.as_mut_vec() }.splice((start, end), replace_with.bytes());
+    }
+
+    /// Converts this `String` into a <code>[Box]<[str]></code>.
+    ///
+    /// This will drop any excess capacity.
+    ///
+    /// [str]: prim@str "str"
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s = String::from("hello");
+    ///
+    /// let b = s.into_boxed_str();
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "box_str", since = "1.4.0")]
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[inline]
+    pub fn into_boxed_str(self) -> Box<str> {
+        let slice = self.vec.into_boxed_slice();
+        unsafe { from_boxed_utf8_unchecked(slice) }
+    }
+}
+
+impl FromUtf8Error {
+    /// Returns a slice of [`u8`]s bytes that were attempted to convert to a `String`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // some invalid bytes, in a vector
+    /// let bytes = vec![0, 159];
+    ///
+    /// let value = String::from_utf8(bytes);
+    ///
+    /// assert_eq!(&[0, 159], value.unwrap_err().as_bytes());
+    /// ```
+    #[must_use]
+    #[stable(feature = "from_utf8_error_as_bytes", since = "1.26.0")]
+    pub fn as_bytes(&self) -> &[u8] {
+        &self.bytes[..]
+    }
+
+    /// Returns the bytes that were attempted to convert to a `String`.
+    ///
+    /// This method is carefully constructed to avoid allocation. It will
+    /// consume the error, moving out the bytes, so that a copy of the bytes
+    /// does not need to be made.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // some invalid bytes, in a vector
+    /// let bytes = vec![0, 159];
+    ///
+    /// let value = String::from_utf8(bytes);
+    ///
+    /// assert_eq!(vec![0, 159], value.unwrap_err().into_bytes());
+    /// ```
+    #[must_use = "`self` will be dropped if the result is not used"]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_bytes(self) -> Vec<u8> {
+        self.bytes
+    }
+
+    /// Fetch a `Utf8Error` to get more details about the conversion failure.
+    ///
+    /// The [`Utf8Error`] type provided by [`std::str`] represents an error that may
+    /// occur when converting a slice of [`u8`]s to a [`&str`]. In this sense, it's
+    /// an analogue to `FromUtf8Error`. See its documentation for more details
+    /// on using it.
+    ///
+    /// [`std::str`]: core::str "std::str"
+    /// [`&str`]: prim@str "&str"
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// // some invalid bytes, in a vector
+    /// let bytes = vec![0, 159];
+    ///
+    /// let error = String::from_utf8(bytes).unwrap_err().utf8_error();
+    ///
+    /// // the first byte is invalid here
+    /// assert_eq!(1, error.valid_up_to());
+    /// ```
+    #[must_use]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn utf8_error(&self) -> Utf8Error {
+        self.error
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for FromUtf8Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(&self.error, f)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for FromUtf16Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt("invalid utf-16: lone surrogate found", f)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Clone for String {
+    fn clone(&self) -> Self {
+        String { vec: self.vec.clone() }
+    }
+
+    fn clone_from(&mut self, source: &Self) {
+        self.vec.clone_from(&source.vec);
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl FromIterator<char> for String {
+    fn from_iter<I: IntoIterator<Item = char>>(iter: I) -> String {
+        let mut buf = String::new();
+        buf.extend(iter);
+        buf
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "string_from_iter_by_ref", since = "1.17.0")]
+impl<'a> FromIterator<&'a char> for String {
+    fn from_iter<I: IntoIterator<Item = &'a char>>(iter: I) -> String {
+        let mut buf = String::new();
+        buf.extend(iter);
+        buf
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> FromIterator<&'a str> for String {
+    fn from_iter<I: IntoIterator<Item = &'a str>>(iter: I) -> String {
+        let mut buf = String::new();
+        buf.extend(iter);
+        buf
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "extend_string", since = "1.4.0")]
+impl FromIterator<String> for String {
+    fn from_iter<I: IntoIterator<Item = String>>(iter: I) -> String {
+        let mut iterator = iter.into_iter();
+
+        // Because we're iterating over `String`s, we can avoid at least
+        // one allocation by getting the first string from the iterator
+        // and appending to it all the subsequent strings.
+        match iterator.next() {
+            None => String::new(),
+            Some(mut buf) => {
+                buf.extend(iterator);
+                buf
+            }
+        }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_str2", since = "1.45.0")]
+impl FromIterator<Box<str>> for String {
+    fn from_iter<I: IntoIterator<Item = Box<str>>>(iter: I) -> String {
+        let mut buf = String::new();
+        buf.extend(iter);
+        buf
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "herd_cows", since = "1.19.0")]
+impl<'a> FromIterator<Cow<'a, str>> for String {
+    fn from_iter<I: IntoIterator<Item = Cow<'a, str>>>(iter: I) -> String {
+        let mut iterator = iter.into_iter();
+
+        // Because we're iterating over CoWs, we can (potentially) avoid at least
+        // one allocation by getting the first item and appending to it all the
+        // subsequent items.
+        match iterator.next() {
+            None => String::new(),
+            Some(cow) => {
+                let mut buf = cow.into_owned();
+                buf.extend(iterator);
+                buf
+            }
+        }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Extend<char> for String {
+    fn extend<I: IntoIterator<Item = char>>(&mut self, iter: I) {
+        let iterator = iter.into_iter();
+        let (lower_bound, _) = iterator.size_hint();
+        self.reserve(lower_bound);
+        iterator.for_each(move |c| self.push(c));
+    }
+
+    #[inline]
+    fn extend_one(&mut self, c: char) {
+        self.push(c);
+    }
+
+    #[inline]
+    fn extend_reserve(&mut self, additional: usize) {
+        self.reserve(additional);
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "extend_ref", since = "1.2.0")]
+impl<'a> Extend<&'a char> for String {
+    fn extend<I: IntoIterator<Item = &'a char>>(&mut self, iter: I) {
+        self.extend(iter.into_iter().cloned());
+    }
+
+    #[inline]
+    fn extend_one(&mut self, &c: &'a char) {
+        self.push(c);
+    }
+
+    #[inline]
+    fn extend_reserve(&mut self, additional: usize) {
+        self.reserve(additional);
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> Extend<&'a str> for String {
+    fn extend<I: IntoIterator<Item = &'a str>>(&mut self, iter: I) {
+        iter.into_iter().for_each(move |s| self.push_str(s));
+    }
+
+    #[inline]
+    fn extend_one(&mut self, s: &'a str) {
+        self.push_str(s);
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_str2", since = "1.45.0")]
+impl Extend<Box<str>> for String {
+    fn extend<I: IntoIterator<Item = Box<str>>>(&mut self, iter: I) {
+        iter.into_iter().for_each(move |s| self.push_str(&s));
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "extend_string", since = "1.4.0")]
+impl Extend<String> for String {
+    fn extend<I: IntoIterator<Item = String>>(&mut self, iter: I) {
+        iter.into_iter().for_each(move |s| self.push_str(&s));
+    }
+
+    #[inline]
+    fn extend_one(&mut self, s: String) {
+        self.push_str(&s);
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "herd_cows", since = "1.19.0")]
+impl<'a> Extend<Cow<'a, str>> for String {
+    fn extend<I: IntoIterator<Item = Cow<'a, str>>>(&mut self, iter: I) {
+        iter.into_iter().for_each(move |s| self.push_str(&s));
+    }
+
+    #[inline]
+    fn extend_one(&mut self, s: Cow<'a, str>) {
+        self.push_str(&s);
+    }
+}
+
+/// A convenience impl that delegates to the impl for `&str`.
+///
+/// # Examples
+///
+/// ```
+/// assert_eq!(String::from("Hello world").find("world"), Some(6));
+/// ```
+#[unstable(
+    feature = "pattern",
+    reason = "API not fully fleshed out and ready to be stabilized",
+    issue = "27721"
+)]
+impl<'a, 'b> Pattern<'a> for &'b String {
+    type Searcher = <&'b str as Pattern<'a>>::Searcher;
+
+    fn into_searcher(self, haystack: &'a str) -> <&'b str as Pattern<'a>>::Searcher {
+        self[..].into_searcher(haystack)
+    }
+
+    #[inline]
+    fn is_contained_in(self, haystack: &'a str) -> bool {
+        self[..].is_contained_in(haystack)
+    }
+
+    #[inline]
+    fn is_prefix_of(self, haystack: &'a str) -> bool {
+        self[..].is_prefix_of(haystack)
+    }
+
+    #[inline]
+    fn strip_prefix_of(self, haystack: &'a str) -> Option<&'a str> {
+        self[..].strip_prefix_of(haystack)
+    }
+
+    #[inline]
+    fn is_suffix_of(self, haystack: &'a str) -> bool {
+        self[..].is_suffix_of(haystack)
+    }
+
+    #[inline]
+    fn strip_suffix_of(self, haystack: &'a str) -> Option<&'a str> {
+        self[..].strip_suffix_of(haystack)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl PartialEq for String {
+    #[inline]
+    fn eq(&self, other: &String) -> bool {
+        PartialEq::eq(&self[..], &other[..])
+    }
+    #[inline]
+    fn ne(&self, other: &String) -> bool {
+        PartialEq::ne(&self[..], &other[..])
+    }
+}
+
+macro_rules! impl_eq {
+    ($lhs:ty, $rhs: ty) => {
+        #[stable(feature = "rust1", since = "1.0.0")]
+        #[allow(unused_lifetimes)]
+        impl<'a, 'b> PartialEq<$rhs> for $lhs {
+            #[inline]
+            fn eq(&self, other: &$rhs) -> bool {
+                PartialEq::eq(&self[..], &other[..])
+            }
+            #[inline]
+            fn ne(&self, other: &$rhs) -> bool {
+                PartialEq::ne(&self[..], &other[..])
+            }
+        }
+
+        #[stable(feature = "rust1", since = "1.0.0")]
+        #[allow(unused_lifetimes)]
+        impl<'a, 'b> PartialEq<$lhs> for $rhs {
+            #[inline]
+            fn eq(&self, other: &$lhs) -> bool {
+                PartialEq::eq(&self[..], &other[..])
+            }
+            #[inline]
+            fn ne(&self, other: &$lhs) -> bool {
+                PartialEq::ne(&self[..], &other[..])
+            }
+        }
+    };
+}
+
+impl_eq! { String, str }
+impl_eq! { String, &'a str }
+#[cfg(not(no_global_oom_handling))]
+impl_eq! { Cow<'a, str>, str }
+#[cfg(not(no_global_oom_handling))]
+impl_eq! { Cow<'a, str>, &'b str }
+#[cfg(not(no_global_oom_handling))]
+impl_eq! { Cow<'a, str>, String }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+impl const Default for String {
+    /// Creates an empty `String`.
+    #[inline]
+    fn default() -> String {
+        String::new()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Display for String {
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Display::fmt(&**self, f)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Debug for String {
+    #[inline]
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(&**self, f)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl hash::Hash for String {
+    #[inline]
+    fn hash<H: hash::Hasher>(&self, hasher: &mut H) {
+        (**self).hash(hasher)
+    }
+}
+
+/// Implements the `+` operator for concatenating two strings.
+///
+/// This consumes the `String` on the left-hand side and re-uses its buffer (growing it if
+/// necessary). This is done to avoid allocating a new `String` and copying the entire contents on
+/// every operation, which would lead to *O*(*n*^2) running time when building an *n*-byte string by
+/// repeated concatenation.
+///
+/// The string on the right-hand side is only borrowed; its contents are copied into the returned
+/// `String`.
+///
+/// # Examples
+///
+/// Concatenating two `String`s takes the first by value and borrows the second:
+///
+/// ```
+/// let a = String::from("hello");
+/// let b = String::from(" world");
+/// let c = a + &b;
+/// // `a` is moved and can no longer be used here.
+/// ```
+///
+/// If you want to keep using the first `String`, you can clone it and append to the clone instead:
+///
+/// ```
+/// let a = String::from("hello");
+/// let b = String::from(" world");
+/// let c = a.clone() + &b;
+/// // `a` is still valid here.
+/// ```
+///
+/// Concatenating `&str` slices can be done by converting the first to a `String`:
+///
+/// ```
+/// let a = "hello";
+/// let b = " world";
+/// let c = a.to_string() + b;
+/// ```
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl Add<&str> for String {
+    type Output = String;
+
+    #[inline]
+    fn add(mut self, other: &str) -> String {
+        self.push_str(other);
+        self
+    }
+}
+
+/// Implements the `+=` operator for appending to a `String`.
+///
+/// This has the same behavior as the [`push_str`][String::push_str] method.
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "stringaddassign", since = "1.12.0")]
+impl AddAssign<&str> for String {
+    #[inline]
+    fn add_assign(&mut self, other: &str) {
+        self.push_str(other);
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Index<ops::Range<usize>> for String {
+    type Output = str;
+
+    #[inline]
+    fn index(&self, index: ops::Range<usize>) -> &str {
+        &self[..][index]
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Index<ops::RangeTo<usize>> for String {
+    type Output = str;
+
+    #[inline]
+    fn index(&self, index: ops::RangeTo<usize>) -> &str {
+        &self[..][index]
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Index<ops::RangeFrom<usize>> for String {
+    type Output = str;
+
+    #[inline]
+    fn index(&self, index: ops::RangeFrom<usize>) -> &str {
+        &self[..][index]
+    }
+}
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Index<ops::RangeFull> for String {
+    type Output = str;
+
+    #[inline]
+    fn index(&self, _index: ops::RangeFull) -> &str {
+        unsafe { str::from_utf8_unchecked(&self.vec) }
+    }
+}
+#[stable(feature = "inclusive_range", since = "1.26.0")]
+impl ops::Index<ops::RangeInclusive<usize>> for String {
+    type Output = str;
+
+    #[inline]
+    fn index(&self, index: ops::RangeInclusive<usize>) -> &str {
+        Index::index(&**self, index)
+    }
+}
+#[stable(feature = "inclusive_range", since = "1.26.0")]
+impl ops::Index<ops::RangeToInclusive<usize>> for String {
+    type Output = str;
+
+    #[inline]
+    fn index(&self, index: ops::RangeToInclusive<usize>) -> &str {
+        Index::index(&**self, index)
+    }
+}
+
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::IndexMut<ops::Range<usize>> for String {
+    #[inline]
+    fn index_mut(&mut self, index: ops::Range<usize>) -> &mut str {
+        &mut self[..][index]
+    }
+}
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::IndexMut<ops::RangeTo<usize>> for String {
+    #[inline]
+    fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut str {
+        &mut self[..][index]
+    }
+}
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::IndexMut<ops::RangeFrom<usize>> for String {
+    #[inline]
+    fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut str {
+        &mut self[..][index]
+    }
+}
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::IndexMut<ops::RangeFull> for String {
+    #[inline]
+    fn index_mut(&mut self, _index: ops::RangeFull) -> &mut str {
+        unsafe { str::from_utf8_unchecked_mut(&mut *self.vec) }
+    }
+}
+#[stable(feature = "inclusive_range", since = "1.26.0")]
+impl ops::IndexMut<ops::RangeInclusive<usize>> for String {
+    #[inline]
+    fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut str {
+        IndexMut::index_mut(&mut **self, index)
+    }
+}
+#[stable(feature = "inclusive_range", since = "1.26.0")]
+impl ops::IndexMut<ops::RangeToInclusive<usize>> for String {
+    #[inline]
+    fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut str {
+        IndexMut::index_mut(&mut **self, index)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl ops::Deref for String {
+    type Target = str;
+
+    #[inline]
+    fn deref(&self) -> &str {
+        unsafe { str::from_utf8_unchecked(&self.vec) }
+    }
+}
+
+#[stable(feature = "derefmut_for_string", since = "1.3.0")]
+impl ops::DerefMut for String {
+    #[inline]
+    fn deref_mut(&mut self) -> &mut str {
+        unsafe { str::from_utf8_unchecked_mut(&mut *self.vec) }
+    }
+}
+
+/// A type alias for [`Infallible`].
+///
+/// This alias exists for backwards compatibility, and may be eventually deprecated.
+///
+/// [`Infallible`]: core::convert::Infallible "convert::Infallible"
+#[stable(feature = "str_parse_error", since = "1.5.0")]
+pub type ParseError = core::convert::Infallible;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl FromStr for String {
+    type Err = core::convert::Infallible;
+    #[inline]
+    fn from_str(s: &str) -> Result<String, Self::Err> {
+        Ok(String::from(s))
+    }
+}
+
+/// A trait for converting a value to a `String`.
+///
+/// This trait is automatically implemented for any type which implements the
+/// [`Display`] trait. As such, `ToString` shouldn't be implemented directly:
+/// [`Display`] should be implemented instead, and you get the `ToString`
+/// implementation for free.
+///
+/// [`Display`]: fmt::Display
+#[cfg_attr(not(test), rustc_diagnostic_item = "ToString")]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait ToString {
+    /// Converts the given value to a `String`.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let i = 5;
+    /// let five = String::from("5");
+    ///
+    /// assert_eq!(five, i.to_string());
+    /// ```
+    #[rustc_conversion_suggestion]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    fn to_string(&self) -> String;
+}
+
+/// # Panics
+///
+/// In this implementation, the `to_string` method panics
+/// if the `Display` implementation returns an error.
+/// This indicates an incorrect `Display` implementation
+/// since `fmt::Write for String` never returns an error itself.
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: fmt::Display + ?Sized> ToString for T {
+    // A common guideline is to not inline generic functions. However,
+    // removing `#[inline]` from this method causes non-negligible regressions.
+    // See <https://github.com/rust-lang/rust/pull/74852>, the last attempt
+    // to try to remove it.
+    #[inline]
+    default fn to_string(&self) -> String {
+        let mut buf = String::new();
+        let mut formatter = core::fmt::Formatter::new(&mut buf);
+        // Bypass format_args!() to avoid write_str with zero-length strs
+        fmt::Display::fmt(self, &mut formatter)
+            .expect("a Display implementation returned an error unexpectedly");
+        buf
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "char_to_string_specialization", since = "1.46.0")]
+impl ToString for char {
+    #[inline]
+    fn to_string(&self) -> String {
+        String::from(self.encode_utf8(&mut [0; 4]))
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "u8_to_string_specialization", since = "1.54.0")]
+impl ToString for u8 {
+    #[inline]
+    fn to_string(&self) -> String {
+        let mut buf = String::with_capacity(3);
+        let mut n = *self;
+        if n >= 10 {
+            if n >= 100 {
+                buf.push((b'0' + n / 100) as char);
+                n %= 100;
+            }
+            buf.push((b'0' + n / 10) as char);
+            n %= 10;
+        }
+        buf.push((b'0' + n) as char);
+        buf
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "i8_to_string_specialization", since = "1.54.0")]
+impl ToString for i8 {
+    #[inline]
+    fn to_string(&self) -> String {
+        let mut buf = String::with_capacity(4);
+        if self.is_negative() {
+            buf.push('-');
+        }
+        let mut n = self.unsigned_abs();
+        if n >= 10 {
+            if n >= 100 {
+                buf.push('1');
+                n -= 100;
+            }
+            buf.push((b'0' + n / 10) as char);
+            n %= 10;
+        }
+        buf.push((b'0' + n) as char);
+        buf
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "str_to_string_specialization", since = "1.9.0")]
+impl ToString for str {
+    #[inline]
+    fn to_string(&self) -> String {
+        String::from(self)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_str_to_string_specialization", since = "1.17.0")]
+impl ToString for Cow<'_, str> {
+    #[inline]
+    fn to_string(&self) -> String {
+        self[..].to_owned()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "string_to_string_specialization", since = "1.17.0")]
+impl ToString for String {
+    #[inline]
+    fn to_string(&self) -> String {
+        self.to_owned()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl AsRef<str> for String {
+    #[inline]
+    fn as_ref(&self) -> &str {
+        self
+    }
+}
+
+#[stable(feature = "string_as_mut", since = "1.43.0")]
+impl AsMut<str> for String {
+    #[inline]
+    fn as_mut(&mut self) -> &mut str {
+        self
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl AsRef<[u8]> for String {
+    #[inline]
+    fn as_ref(&self) -> &[u8] {
+        self.as_bytes()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl From<&str> for String {
+    /// Converts a `&str` into a [`String`].
+    ///
+    /// The result is allocated on the heap.
+    #[inline]
+    fn from(s: &str) -> String {
+        s.to_owned()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "from_mut_str_for_string", since = "1.44.0")]
+impl From<&mut str> for String {
+    /// Converts a `&mut str` into a [`String`].
+    ///
+    /// The result is allocated on the heap.
+    #[inline]
+    fn from(s: &mut str) -> String {
+        s.to_owned()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "from_ref_string", since = "1.35.0")]
+impl From<&String> for String {
+    /// Converts a `&String` into a [`String`].
+    ///
+    /// This clones `s` and returns the clone.
+    #[inline]
+    fn from(s: &String) -> String {
+        s.clone()
+    }
+}
+
+// note: test pulls in libstd, which causes errors here
+#[cfg(not(test))]
+#[stable(feature = "string_from_box", since = "1.18.0")]
+impl From<Box<str>> for String {
+    /// Converts the given boxed `str` slice to a [`String`].
+    /// It is notable that the `str` slice is owned.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s1: String = String::from("hello world");
+    /// let s2: Box<str> = s1.into_boxed_str();
+    /// let s3: String = String::from(s2);
+    ///
+    /// assert_eq!("hello world", s3)
+    /// ```
+    fn from(s: Box<str>) -> String {
+        s.into_string()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "box_from_str", since = "1.20.0")]
+impl From<String> for Box<str> {
+    /// Converts the given [`String`] to a boxed `str` slice that is owned.
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s1: String = String::from("hello world");
+    /// let s2: Box<str> = Box::from(s1);
+    /// let s3: String = String::from(s2);
+    ///
+    /// assert_eq!("hello world", s3)
+    /// ```
+    fn from(s: String) -> Box<str> {
+        s.into_boxed_str()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "string_from_cow_str", since = "1.14.0")]
+impl<'a> From<Cow<'a, str>> for String {
+    /// Converts a clone-on-write string to an owned
+    /// instance of [`String`].
+    ///
+    /// This extracts the owned string,
+    /// clones the string if it is not already owned.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use std::borrow::Cow;
+    /// // If the string is not owned...
+    /// let cow: Cow<str> = Cow::Borrowed("eggplant");
+    /// // It will allocate on the heap and copy the string.
+    /// let owned: String = String::from(cow);
+    /// assert_eq!(&owned[..], "eggplant");
+    /// ```
+    fn from(s: Cow<'a, str>) -> String {
+        s.into_owned()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> From<&'a str> for Cow<'a, str> {
+    /// Converts a string slice into a [`Borrowed`] variant.
+    /// No heap allocation is performed, and the string
+    /// is not copied.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use std::borrow::Cow;
+    /// assert_eq!(Cow::from("eggplant"), Cow::Borrowed("eggplant"));
+    /// ```
+    ///
+    /// [`Borrowed`]: crate::borrow::Cow::Borrowed "borrow::Cow::Borrowed"
+    #[inline]
+    fn from(s: &'a str) -> Cow<'a, str> {
+        Cow::Borrowed(s)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a> From<String> for Cow<'a, str> {
+    /// Converts a [`String`] into an [`Owned`] variant.
+    /// No heap allocation is performed, and the string
+    /// is not copied.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use std::borrow::Cow;
+    /// let s = "eggplant".to_string();
+    /// let s2 = "eggplant".to_string();
+    /// assert_eq!(Cow::from(s), Cow::<'static, str>::Owned(s2));
+    /// ```
+    ///
+    /// [`Owned`]: crate::borrow::Cow::Owned "borrow::Cow::Owned"
+    #[inline]
+    fn from(s: String) -> Cow<'a, str> {
+        Cow::Owned(s)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_from_string_ref", since = "1.28.0")]
+impl<'a> From<&'a String> for Cow<'a, str> {
+    /// Converts a [`String`] reference into a [`Borrowed`] variant.
+    /// No heap allocation is performed, and the string
+    /// is not copied.
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// # use std::borrow::Cow;
+    /// let s = "eggplant".to_string();
+    /// assert_eq!(Cow::from(&s), Cow::Borrowed("eggplant"));
+    /// ```
+    ///
+    /// [`Borrowed`]: crate::borrow::Cow::Borrowed "borrow::Cow::Borrowed"
+    #[inline]
+    fn from(s: &'a String) -> Cow<'a, str> {
+        Cow::Borrowed(s.as_str())
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_str_from_iter", since = "1.12.0")]
+impl<'a> FromIterator<char> for Cow<'a, str> {
+    fn from_iter<I: IntoIterator<Item = char>>(it: I) -> Cow<'a, str> {
+        Cow::Owned(FromIterator::from_iter(it))
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_str_from_iter", since = "1.12.0")]
+impl<'a, 'b> FromIterator<&'b str> for Cow<'a, str> {
+    fn from_iter<I: IntoIterator<Item = &'b str>>(it: I) -> Cow<'a, str> {
+        Cow::Owned(FromIterator::from_iter(it))
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "cow_str_from_iter", since = "1.12.0")]
+impl<'a> FromIterator<String> for Cow<'a, str> {
+    fn from_iter<I: IntoIterator<Item = String>>(it: I) -> Cow<'a, str> {
+        Cow::Owned(FromIterator::from_iter(it))
+    }
+}
+
+#[stable(feature = "from_string_for_vec_u8", since = "1.14.0")]
+impl From<String> for Vec<u8> {
+    /// Converts the given [`String`] to a vector [`Vec`] that holds values of type [`u8`].
+    ///
+    /// # Examples
+    ///
+    /// Basic usage:
+    ///
+    /// ```
+    /// let s1 = String::from("hello world");
+    /// let v1 = Vec::from(s1);
+    ///
+    /// for b in v1 {
+    ///     println!("{b}");
+    /// }
+    /// ```
+    fn from(string: String) -> Vec<u8> {
+        string.into_bytes()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl fmt::Write for String {
+    #[inline]
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        self.push_str(s);
+        Ok(())
+    }
+
+    #[inline]
+    fn write_char(&mut self, c: char) -> fmt::Result {
+        self.push(c);
+        Ok(())
+    }
+}
+
+/// A draining iterator for `String`.
+///
+/// This struct is created by the [`drain`] method on [`String`]. See its
+/// documentation for more.
+///
+/// [`drain`]: String::drain
+#[stable(feature = "drain", since = "1.6.0")]
+pub struct Drain<'a> {
+    /// Will be used as &'a mut String in the destructor
+    string: *mut String,
+    /// Start of part to remove
+    start: usize,
+    /// End of part to remove
+    end: usize,
+    /// Current remaining range to remove
+    iter: Chars<'a>,
+}
+
+#[stable(feature = "collection_debug", since = "1.17.0")]
+impl fmt::Debug for Drain<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("Drain").field(&self.as_str()).finish()
+    }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+unsafe impl Sync for Drain<'_> {}
+#[stable(feature = "drain", since = "1.6.0")]
+unsafe impl Send for Drain<'_> {}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl Drop for Drain<'_> {
+    fn drop(&mut self) {
+        unsafe {
+            // Use Vec::drain. "Reaffirm" the bounds checks to avoid
+            // panic code being inserted again.
+            let self_vec = (*self.string).as_mut_vec();
+            if self.start <= self.end && self.end <= self_vec.len() {
+                self_vec.drain(self.start..self.end);
+            }
+        }
+    }
+}
+
+impl<'a> Drain<'a> {
+    /// Returns the remaining (sub)string of this iterator as a slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut s = String::from("abc");
+    /// let mut drain = s.drain(..);
+    /// assert_eq!(drain.as_str(), "abc");
+    /// let _ = drain.next().unwrap();
+    /// assert_eq!(drain.as_str(), "bc");
+    /// ```
+    #[must_use]
+    #[stable(feature = "string_drain_as_str", since = "1.55.0")]
+    pub fn as_str(&self) -> &str {
+        self.iter.as_str()
+    }
+}
+
+#[stable(feature = "string_drain_as_str", since = "1.55.0")]
+impl<'a> AsRef<str> for Drain<'a> {
+    fn as_ref(&self) -> &str {
+        self.as_str()
+    }
+}
+
+#[stable(feature = "string_drain_as_str", since = "1.55.0")]
+impl<'a> AsRef<[u8]> for Drain<'a> {
+    fn as_ref(&self) -> &[u8] {
+        self.as_str().as_bytes()
+    }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl Iterator for Drain<'_> {
+    type Item = char;
+
+    #[inline]
+    fn next(&mut self) -> Option<char> {
+        self.iter.next()
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+
+    #[inline]
+    fn last(mut self) -> Option<char> {
+        self.next_back()
+    }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl DoubleEndedIterator for Drain<'_> {
+    #[inline]
+    fn next_back(&mut self) -> Option<char> {
+        self.iter.next_back()
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl FusedIterator for Drain<'_> {}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "from_char_for_string", since = "1.46.0")]
+impl From<char> for String {
+    /// Allocates an owned [`String`] from a single character.
+    ///
+    /// # Example
+    /// ```rust
+    /// let c: char = 'a';
+    /// let s: String = String::from(c);
+    /// assert_eq!("a", &s[..]);
+    /// ```
+    #[inline]
+    fn from(c: char) -> Self {
+        c.to_string()
+    }
+}
diff --git a/rust/alloc/vec/drain.rs b/rust/alloc/vec/drain.rs
new file mode 100644
index 000000000000..b6a5f98e4fcd
--- /dev/null
+++ b/rust/alloc/vec/drain.rs
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use crate::alloc::{Allocator, Global};
+use core::fmt;
+use core::iter::{FusedIterator, TrustedLen};
+use core::mem;
+use core::ptr::{self, NonNull};
+use core::slice::{self};
+
+use super::Vec;
+
+/// A draining iterator for `Vec<T>`.
+///
+/// This `struct` is created by [`Vec::drain`].
+/// See its documentation for more.
+///
+/// # Example
+///
+/// ```
+/// let mut v = vec![0, 1, 2];
+/// let iter: std::vec::Drain<_> = v.drain(..);
+/// ```
+#[stable(feature = "drain", since = "1.6.0")]
+pub struct Drain<
+    'a,
+    T: 'a,
+    #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator + 'a = Global,
+> {
+    /// Index of tail to preserve
+    pub(super) tail_start: usize,
+    /// Length of tail
+    pub(super) tail_len: usize,
+    /// Current remaining range to remove
+    pub(super) iter: slice::Iter<'a, T>,
+    pub(super) vec: NonNull<Vec<T, A>>,
+}
+
+#[stable(feature = "collection_debug", since = "1.17.0")]
+impl<T: fmt::Debug, A: Allocator> fmt::Debug for Drain<'_, T, A> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("Drain").field(&self.iter.as_slice()).finish()
+    }
+}
+
+impl<'a, T, A: Allocator> Drain<'a, T, A> {
+    /// Returns the remaining items of this iterator as a slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec!['a', 'b', 'c'];
+    /// let mut drain = vec.drain(..);
+    /// assert_eq!(drain.as_slice(), &['a', 'b', 'c']);
+    /// let _ = drain.next().unwrap();
+    /// assert_eq!(drain.as_slice(), &['b', 'c']);
+    /// ```
+    #[must_use]
+    #[stable(feature = "vec_drain_as_slice", since = "1.46.0")]
+    pub fn as_slice(&self) -> &[T] {
+        self.iter.as_slice()
+    }
+
+    /// Returns a reference to the underlying allocator.
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[must_use]
+    #[inline]
+    pub fn allocator(&self) -> &A {
+        unsafe { self.vec.as_ref().allocator() }
+    }
+}
+
+#[stable(feature = "vec_drain_as_slice", since = "1.46.0")]
+impl<'a, T, A: Allocator> AsRef<[T]> for Drain<'a, T, A> {
+    fn as_ref(&self) -> &[T] {
+        self.as_slice()
+    }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+unsafe impl<T: Sync, A: Sync + Allocator> Sync for Drain<'_, T, A> {}
+#[stable(feature = "drain", since = "1.6.0")]
+unsafe impl<T: Send, A: Send + Allocator> Send for Drain<'_, T, A> {}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl<T, A: Allocator> Iterator for Drain<'_, T, A> {
+    type Item = T;
+
+    #[inline]
+    fn next(&mut self) -> Option<T> {
+        self.iter.next().map(|elt| unsafe { ptr::read(elt as *const _) })
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl<T, A: Allocator> DoubleEndedIterator for Drain<'_, T, A> {
+    #[inline]
+    fn next_back(&mut self) -> Option<T> {
+        self.iter.next_back().map(|elt| unsafe { ptr::read(elt as *const _) })
+    }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl<T, A: Allocator> Drop for Drain<'_, T, A> {
+    fn drop(&mut self) {
+        /// Moves back the un-`Drain`ed elements to restore the original `Vec`.
+        struct DropGuard<'r, 'a, T, A: Allocator>(&'r mut Drain<'a, T, A>);
+
+        impl<'r, 'a, T, A: Allocator> Drop for DropGuard<'r, 'a, T, A> {
+            fn drop(&mut self) {
+                if self.0.tail_len > 0 {
+                    unsafe {
+                        let source_vec = self.0.vec.as_mut();
+                        // memmove back untouched tail, update to new length
+                        let start = source_vec.len();
+                        let tail = self.0.tail_start;
+                        if tail != start {
+                            let src = source_vec.as_ptr().add(tail);
+                            let dst = source_vec.as_mut_ptr().add(start);
+                            ptr::copy(src, dst, self.0.tail_len);
+                        }
+                        source_vec.set_len(start + self.0.tail_len);
+                    }
+                }
+            }
+        }
+
+        let iter = mem::replace(&mut self.iter, (&mut []).iter());
+        let drop_len = iter.len();
+
+        let mut vec = self.vec;
+
+        if mem::size_of::<T>() == 0 {
+            // ZSTs have no identity, so we don't need to move them around, we only need to drop the correct amount.
+            // this can be achieved by manipulating the Vec length instead of moving values out from `iter`.
+            unsafe {
+                let vec = vec.as_mut();
+                let old_len = vec.len();
+                vec.set_len(old_len + drop_len + self.tail_len);
+                vec.truncate(old_len + self.tail_len);
+            }
+
+            return;
+        }
+
+        // ensure elements are moved back into their appropriate places, even when drop_in_place panics
+        let _guard = DropGuard(self);
+
+        if drop_len == 0 {
+            return;
+        }
+
+        // as_slice() must only be called when iter.len() is > 0 because
+        // vec::Splice modifies vec::Drain fields and may grow the vec which would invalidate
+        // the iterator's internal pointers. Creating a reference to deallocated memory
+        // is invalid even when it is zero-length
+        let drop_ptr = iter.as_slice().as_ptr();
+
+        unsafe {
+            // drop_ptr comes from a slice::Iter which only gives us a &[T] but for drop_in_place
+            // a pointer with mutable provenance is necessary. Therefore we must reconstruct
+            // it from the original vec but also avoid creating a &mut to the front since that could
+            // invalidate raw pointers to it which some unsafe code might rely on.
+            let vec_ptr = vec.as_mut().as_mut_ptr();
+            let drop_offset = drop_ptr.sub_ptr(vec_ptr);
+            let to_drop = ptr::slice_from_raw_parts_mut(vec_ptr.add(drop_offset), drop_len);
+            ptr::drop_in_place(to_drop);
+        }
+    }
+}
+
+#[stable(feature = "drain", since = "1.6.0")]
+impl<T, A: Allocator> ExactSizeIterator for Drain<'_, T, A> {
+    fn is_empty(&self) -> bool {
+        self.iter.is_empty()
+    }
+}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<T, A: Allocator> TrustedLen for Drain<'_, T, A> {}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<T, A: Allocator> FusedIterator for Drain<'_, T, A> {}
diff --git a/rust/alloc/vec/drain_filter.rs b/rust/alloc/vec/drain_filter.rs
new file mode 100644
index 000000000000..b04fce041622
--- /dev/null
+++ b/rust/alloc/vec/drain_filter.rs
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use crate::alloc::{Allocator, Global};
+use core::ptr::{self};
+use core::slice::{self};
+
+use super::Vec;
+
+/// An iterator which uses a closure to determine if an element should be removed.
+///
+/// This struct is created by [`Vec::drain_filter`].
+/// See its documentation for more.
+///
+/// # Example
+///
+/// ```
+/// #![feature(drain_filter)]
+///
+/// let mut v = vec![0, 1, 2];
+/// let iter: std::vec::DrainFilter<_, _> = v.drain_filter(|x| *x % 2 == 0);
+/// ```
+#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+#[derive(Debug)]
+pub struct DrainFilter<
+    'a,
+    T,
+    F,
+    #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
+> where
+    F: FnMut(&mut T) -> bool,
+{
+    pub(super) vec: &'a mut Vec<T, A>,
+    /// The index of the item that will be inspected by the next call to `next`.
+    pub(super) idx: usize,
+    /// The number of items that have been drained (removed) thus far.
+    pub(super) del: usize,
+    /// The original length of `vec` prior to draining.
+    pub(super) old_len: usize,
+    /// The filter test predicate.
+    pub(super) pred: F,
+    /// A flag that indicates a panic has occurred in the filter test predicate.
+    /// This is used as a hint in the drop implementation to prevent consumption
+    /// of the remainder of the `DrainFilter`. Any unprocessed items will be
+    /// backshifted in the `vec`, but no further items will be dropped or
+    /// tested by the filter predicate.
+    pub(super) panic_flag: bool,
+}
+
+impl<T, F, A: Allocator> DrainFilter<'_, T, F, A>
+where
+    F: FnMut(&mut T) -> bool,
+{
+    /// Returns a reference to the underlying allocator.
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[inline]
+    pub fn allocator(&self) -> &A {
+        self.vec.allocator()
+    }
+}
+
+#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+impl<T, F, A: Allocator> Iterator for DrainFilter<'_, T, F, A>
+where
+    F: FnMut(&mut T) -> bool,
+{
+    type Item = T;
+
+    fn next(&mut self) -> Option<T> {
+        unsafe {
+            while self.idx < self.old_len {
+                let i = self.idx;
+                let v = slice::from_raw_parts_mut(self.vec.as_mut_ptr(), self.old_len);
+                self.panic_flag = true;
+                let drained = (self.pred)(&mut v[i]);
+                self.panic_flag = false;
+                // Update the index *after* the predicate is called. If the index
+                // is updated prior and the predicate panics, the element at this
+                // index would be leaked.
+                self.idx += 1;
+                if drained {
+                    self.del += 1;
+                    return Some(ptr::read(&v[i]));
+                } else if self.del > 0 {
+                    let del = self.del;
+                    let src: *const T = &v[i];
+                    let dst: *mut T = &mut v[i - del];
+                    ptr::copy_nonoverlapping(src, dst, 1);
+                }
+            }
+            None
+        }
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (0, Some(self.old_len - self.idx))
+    }
+}
+
+#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+impl<T, F, A: Allocator> Drop for DrainFilter<'_, T, F, A>
+where
+    F: FnMut(&mut T) -> bool,
+{
+    fn drop(&mut self) {
+        struct BackshiftOnDrop<'a, 'b, T, F, A: Allocator>
+        where
+            F: FnMut(&mut T) -> bool,
+        {
+            drain: &'b mut DrainFilter<'a, T, F, A>,
+        }
+
+        impl<'a, 'b, T, F, A: Allocator> Drop for BackshiftOnDrop<'a, 'b, T, F, A>
+        where
+            F: FnMut(&mut T) -> bool,
+        {
+            fn drop(&mut self) {
+                unsafe {
+                    if self.drain.idx < self.drain.old_len && self.drain.del > 0 {
+                        // This is a pretty messed up state, and there isn't really an
+                        // obviously right thing to do. We don't want to keep trying
+                        // to execute `pred`, so we just backshift all the unprocessed
+                        // elements and tell the vec that they still exist. The backshift
+                        // is required to prevent a double-drop of the last successfully
+                        // drained item prior to a panic in the predicate.
+                        let ptr = self.drain.vec.as_mut_ptr();
+                        let src = ptr.add(self.drain.idx);
+                        let dst = src.sub(self.drain.del);
+                        let tail_len = self.drain.old_len - self.drain.idx;
+                        src.copy_to(dst, tail_len);
+                    }
+                    self.drain.vec.set_len(self.drain.old_len - self.drain.del);
+                }
+            }
+        }
+
+        let backshift = BackshiftOnDrop { drain: self };
+
+        // Attempt to consume any remaining elements if the filter predicate
+        // has not yet panicked. We'll backshift any remaining elements
+        // whether we've already panicked or if the consumption here panics.
+        if !backshift.drain.panic_flag {
+            backshift.drain.for_each(drop);
+        }
+    }
+}
diff --git a/rust/alloc/vec/into_iter.rs b/rust/alloc/vec/into_iter.rs
new file mode 100644
index 000000000000..09cfee0ae631
--- /dev/null
+++ b/rust/alloc/vec/into_iter.rs
@@ -0,0 +1,365 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+#[cfg(not(no_global_oom_handling))]
+use super::AsVecIntoIter;
+use crate::alloc::{Allocator, Global};
+use crate::raw_vec::RawVec;
+use core::fmt;
+use core::intrinsics::arith_offset;
+use core::iter::{
+    FusedIterator, InPlaceIterable, SourceIter, TrustedLen, TrustedRandomAccessNoCoerce,
+};
+use core::marker::PhantomData;
+use core::mem::{self, ManuallyDrop};
+#[cfg(not(no_global_oom_handling))]
+use core::ops::Deref;
+use core::ptr::{self, NonNull};
+use core::slice::{self};
+
+/// An iterator that moves out of a vector.
+///
+/// This `struct` is created by the `into_iter` method on [`Vec`](super::Vec)
+/// (provided by the [`IntoIterator`] trait).
+///
+/// # Example
+///
+/// ```
+/// let v = vec![0, 1, 2];
+/// let iter: std::vec::IntoIter<_> = v.into_iter();
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_insignificant_dtor]
+pub struct IntoIter<
+    T,
+    #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global,
+> {
+    pub(super) buf: NonNull<T>,
+    pub(super) phantom: PhantomData<T>,
+    pub(super) cap: usize,
+    // the drop impl reconstructs a RawVec from buf, cap and alloc
+    // to avoid dropping the allocator twice we need to wrap it into ManuallyDrop
+    pub(super) alloc: ManuallyDrop<A>,
+    pub(super) ptr: *const T,
+    pub(super) end: *const T,
+}
+
+#[stable(feature = "vec_intoiter_debug", since = "1.13.0")]
+impl<T: fmt::Debug, A: Allocator> fmt::Debug for IntoIter<T, A> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_tuple("IntoIter").field(&self.as_slice()).finish()
+    }
+}
+
+impl<T, A: Allocator> IntoIter<T, A> {
+    /// Returns the remaining items of this iterator as a slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let vec = vec!['a', 'b', 'c'];
+    /// let mut into_iter = vec.into_iter();
+    /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+    /// let _ = into_iter.next().unwrap();
+    /// assert_eq!(into_iter.as_slice(), &['b', 'c']);
+    /// ```
+    #[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
+    pub fn as_slice(&self) -> &[T] {
+        unsafe { slice::from_raw_parts(self.ptr, self.len()) }
+    }
+
+    /// Returns the remaining items of this iterator as a mutable slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let vec = vec!['a', 'b', 'c'];
+    /// let mut into_iter = vec.into_iter();
+    /// assert_eq!(into_iter.as_slice(), &['a', 'b', 'c']);
+    /// into_iter.as_mut_slice()[2] = 'z';
+    /// assert_eq!(into_iter.next().unwrap(), 'a');
+    /// assert_eq!(into_iter.next().unwrap(), 'b');
+    /// assert_eq!(into_iter.next().unwrap(), 'z');
+    /// ```
+    #[stable(feature = "vec_into_iter_as_slice", since = "1.15.0")]
+    pub fn as_mut_slice(&mut self) -> &mut [T] {
+        unsafe { &mut *self.as_raw_mut_slice() }
+    }
+
+    /// Returns a reference to the underlying allocator.
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[inline]
+    pub fn allocator(&self) -> &A {
+        &self.alloc
+    }
+
+    fn as_raw_mut_slice(&mut self) -> *mut [T] {
+        ptr::slice_from_raw_parts_mut(self.ptr as *mut T, self.len())
+    }
+
+    /// Drops remaining elements and relinquishes the backing allocation.
+    ///
+    /// This is roughly equivalent to the following, but more efficient
+    ///
+    /// ```
+    /// # let mut into_iter = Vec::<u8>::with_capacity(10).into_iter();
+    /// (&mut into_iter).for_each(core::mem::drop);
+    /// unsafe { core::ptr::write(&mut into_iter, Vec::new().into_iter()); }
+    /// ```
+    ///
+    /// This method is used by in-place iteration, refer to the vec::in_place_collect
+    /// documentation for an overview.
+    #[cfg(not(no_global_oom_handling))]
+    pub(super) fn forget_allocation_drop_remaining(&mut self) {
+        let remaining = self.as_raw_mut_slice();
+
+        // overwrite the individual fields instead of creating a new
+        // struct and then overwriting &mut self.
+        // this creates less assembly
+        self.cap = 0;
+        self.buf = unsafe { NonNull::new_unchecked(RawVec::NEW.ptr()) };
+        self.ptr = self.buf.as_ptr();
+        self.end = self.buf.as_ptr();
+
+        unsafe {
+            ptr::drop_in_place(remaining);
+        }
+    }
+
+    /// Forgets to Drop the remaining elements while still allowing the backing allocation to be freed.
+    pub(crate) fn forget_remaining_elements(&mut self) {
+        self.ptr = self.end;
+    }
+}
+
+#[stable(feature = "vec_intoiter_as_ref", since = "1.46.0")]
+impl<T, A: Allocator> AsRef<[T]> for IntoIter<T, A> {
+    fn as_ref(&self) -> &[T] {
+        self.as_slice()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<T: Send, A: Allocator + Send> Send for IntoIter<T, A> {}
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<T: Sync, A: Allocator + Sync> Sync for IntoIter<T, A> {}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> Iterator for IntoIter<T, A> {
+    type Item = T;
+
+    #[inline]
+    fn next(&mut self) -> Option<T> {
+        if self.ptr as *const _ == self.end {
+            None
+        } else if mem::size_of::<T>() == 0 {
+            // purposefully don't use 'ptr.offset' because for
+            // vectors with 0-size elements this would return the
+            // same pointer.
+            self.ptr = unsafe { arith_offset(self.ptr as *const i8, 1) as *mut T };
+
+            // Make up a value of this ZST.
+            Some(unsafe { mem::zeroed() })
+        } else {
+            let old = self.ptr;
+            self.ptr = unsafe { self.ptr.offset(1) };
+
+            Some(unsafe { ptr::read(old) })
+        }
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let exact = if mem::size_of::<T>() == 0 {
+            self.end.addr().wrapping_sub(self.ptr.addr())
+        } else {
+            unsafe { self.end.sub_ptr(self.ptr) }
+        };
+        (exact, Some(exact))
+    }
+
+    #[inline]
+    fn advance_by(&mut self, n: usize) -> Result<(), usize> {
+        let step_size = self.len().min(n);
+        let to_drop = ptr::slice_from_raw_parts_mut(self.ptr as *mut T, step_size);
+        if mem::size_of::<T>() == 0 {
+            // SAFETY: due to unchecked casts of unsigned amounts to signed offsets the wraparound
+            // effectively results in unsigned pointers representing positions 0..usize::MAX,
+            // which is valid for ZSTs.
+            self.ptr = unsafe { arith_offset(self.ptr as *const i8, step_size as isize) as *mut T }
+        } else {
+            // SAFETY: the min() above ensures that step_size is in bounds
+            self.ptr = unsafe { self.ptr.add(step_size) };
+        }
+        // SAFETY: the min() above ensures that step_size is in bounds
+        unsafe {
+            ptr::drop_in_place(to_drop);
+        }
+        if step_size < n {
+            return Err(step_size);
+        }
+        Ok(())
+    }
+
+    #[inline]
+    fn count(self) -> usize {
+        self.len()
+    }
+
+    unsafe fn __iterator_get_unchecked(&mut self, i: usize) -> Self::Item
+    where
+        Self: TrustedRandomAccessNoCoerce,
+    {
+        // SAFETY: the caller must guarantee that `i` is in bounds of the
+        // `Vec<T>`, so `i` cannot overflow an `isize`, and the `self.ptr.add(i)`
+        // is guaranteed to pointer to an element of the `Vec<T>` and
+        // thus guaranteed to be valid to dereference.
+        //
+        // Also note the implementation of `Self: TrustedRandomAccess` requires
+        // that `T: Copy` so reading elements from the buffer doesn't invalidate
+        // them for `Drop`.
+        unsafe {
+            if mem::size_of::<T>() == 0 { mem::zeroed() } else { ptr::read(self.ptr.add(i)) }
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> DoubleEndedIterator for IntoIter<T, A> {
+    #[inline]
+    fn next_back(&mut self) -> Option<T> {
+        if self.end == self.ptr {
+            None
+        } else if mem::size_of::<T>() == 0 {
+            // See above for why 'ptr.offset' isn't used
+            self.end = unsafe { arith_offset(self.end as *const i8, -1) as *mut T };
+
+            // Make up a value of this ZST.
+            Some(unsafe { mem::zeroed() })
+        } else {
+            self.end = unsafe { self.end.offset(-1) };
+
+            Some(unsafe { ptr::read(self.end) })
+        }
+    }
+
+    #[inline]
+    fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
+        let step_size = self.len().min(n);
+        if mem::size_of::<T>() == 0 {
+            // SAFETY: same as for advance_by()
+            self.end = unsafe {
+                arith_offset(self.end as *const i8, step_size.wrapping_neg() as isize) as *mut T
+            }
+        } else {
+            // SAFETY: same as for advance_by()
+            self.end = unsafe { self.end.offset(step_size.wrapping_neg() as isize) };
+        }
+        let to_drop = ptr::slice_from_raw_parts_mut(self.end as *mut T, step_size);
+        // SAFETY: same as for advance_by()
+        unsafe {
+            ptr::drop_in_place(to_drop);
+        }
+        if step_size < n {
+            return Err(step_size);
+        }
+        Ok(())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> ExactSizeIterator for IntoIter<T, A> {
+    fn is_empty(&self) -> bool {
+        self.ptr == self.end
+    }
+}
+
+#[stable(feature = "fused", since = "1.26.0")]
+impl<T, A: Allocator> FusedIterator for IntoIter<T, A> {}
+
+#[unstable(feature = "trusted_len", issue = "37572")]
+unsafe impl<T, A: Allocator> TrustedLen for IntoIter<T, A> {}
+
+#[doc(hidden)]
+#[unstable(issue = "none", feature = "std_internals")]
+#[rustc_unsafe_specialization_marker]
+pub trait NonDrop {}
+
+// T: Copy as approximation for !Drop since get_unchecked does not advance self.ptr
+// and thus we can't implement drop-handling
+#[unstable(issue = "none", feature = "std_internals")]
+impl<T: Copy> NonDrop for T {}
+
+#[doc(hidden)]
+#[unstable(issue = "none", feature = "std_internals")]
+// TrustedRandomAccess (without NoCoerce) must not be implemented because
+// subtypes/supertypes of `T` might not be `NonDrop`
+unsafe impl<T, A: Allocator> TrustedRandomAccessNoCoerce for IntoIter<T, A>
+where
+    T: NonDrop,
+{
+    const MAY_HAVE_SIDE_EFFECT: bool = false;
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_into_iter_clone", since = "1.8.0")]
+impl<T: Clone, A: Allocator + Clone> Clone for IntoIter<T, A> {
+    #[cfg(not(test))]
+    fn clone(&self) -> Self {
+        self.as_slice().to_vec_in(self.alloc.deref().clone()).into_iter()
+    }
+    #[cfg(test)]
+    fn clone(&self) -> Self {
+        crate::slice::to_vec(self.as_slice(), self.alloc.deref().clone()).into_iter()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<#[may_dangle] T, A: Allocator> Drop for IntoIter<T, A> {
+    fn drop(&mut self) {
+        struct DropGuard<'a, T, A: Allocator>(&'a mut IntoIter<T, A>);
+
+        impl<T, A: Allocator> Drop for DropGuard<'_, T, A> {
+            fn drop(&mut self) {
+                unsafe {
+                    // `IntoIter::alloc` is not used anymore after this and will be dropped by RawVec
+                    let alloc = ManuallyDrop::take(&mut self.0.alloc);
+                    // RawVec handles deallocation
+                    let _ = RawVec::from_raw_parts_in(self.0.buf.as_ptr(), self.0.cap, alloc);
+                }
+            }
+        }
+
+        let guard = DropGuard(self);
+        // destroy the remaining elements
+        unsafe {
+            ptr::drop_in_place(guard.0.as_raw_mut_slice());
+        }
+        // now `guard` will be dropped and do the rest
+    }
+}
+
+// In addition to the SAFETY invariants of the following three unsafe traits
+// also refer to the vec::in_place_collect module documentation to get an overview
+#[unstable(issue = "none", feature = "inplace_iteration")]
+#[doc(hidden)]
+unsafe impl<T, A: Allocator> InPlaceIterable for IntoIter<T, A> {}
+
+#[unstable(issue = "none", feature = "inplace_iteration")]
+#[doc(hidden)]
+unsafe impl<T, A: Allocator> SourceIter for IntoIter<T, A> {
+    type Source = Self;
+
+    #[inline]
+    unsafe fn as_inner(&mut self) -> &mut Self::Source {
+        self
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+unsafe impl<T> AsVecIntoIter for IntoIter<T> {
+    type Item = T;
+
+    fn as_into_iter(&mut self) -> &mut IntoIter<Self::Item> {
+        self
+    }
+}
diff --git a/rust/alloc/vec/is_zero.rs b/rust/alloc/vec/is_zero.rs
new file mode 100644
index 000000000000..377f3d172777
--- /dev/null
+++ b/rust/alloc/vec/is_zero.rs
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use crate::boxed::Box;
+
+#[rustc_specialization_trait]
+pub(super) unsafe trait IsZero {
+    /// Whether this value's representation is all zeros
+    fn is_zero(&self) -> bool;
+}
+
+macro_rules! impl_is_zero {
+    ($t:ty, $is_zero:expr) => {
+        unsafe impl IsZero for $t {
+            #[inline]
+            fn is_zero(&self) -> bool {
+                $is_zero(*self)
+            }
+        }
+    };
+}
+
+impl_is_zero!(i16, |x| x == 0);
+impl_is_zero!(i32, |x| x == 0);
+impl_is_zero!(i64, |x| x == 0);
+impl_is_zero!(i128, |x| x == 0);
+impl_is_zero!(isize, |x| x == 0);
+
+impl_is_zero!(u16, |x| x == 0);
+impl_is_zero!(u32, |x| x == 0);
+impl_is_zero!(u64, |x| x == 0);
+impl_is_zero!(u128, |x| x == 0);
+impl_is_zero!(usize, |x| x == 0);
+
+impl_is_zero!(bool, |x| x == false);
+impl_is_zero!(char, |x| x == '\0');
+
+impl_is_zero!(f32, |x: f32| x.to_bits() == 0);
+impl_is_zero!(f64, |x: f64| x.to_bits() == 0);
+
+unsafe impl<T> IsZero for *const T {
+    #[inline]
+    fn is_zero(&self) -> bool {
+        (*self).is_null()
+    }
+}
+
+unsafe impl<T> IsZero for *mut T {
+    #[inline]
+    fn is_zero(&self) -> bool {
+        (*self).is_null()
+    }
+}
+
+unsafe impl<T: IsZero, const N: usize> IsZero for [T; N] {
+    #[inline]
+    fn is_zero(&self) -> bool {
+        // Because this is generated as a runtime check, it's not obvious that
+        // it's worth doing if the array is really long.  The threshold here
+        // is largely arbitrary, but was picked because as of 2022-05-01 LLVM
+        // can const-fold the check in `vec![[0; 32]; n]` but not in
+        // `vec![[0; 64]; n]`: https://godbolt.org/z/WTzjzfs5b
+        // Feel free to tweak if you have better evidence.
+
+        N <= 32 && self.iter().all(IsZero::is_zero)
+    }
+}
+
+// `Option<&T>` and `Option<Box<T>>` are guaranteed to represent `None` as null.
+// For fat pointers, the bytes that would be the pointer metadata in the `Some`
+// variant are padding in the `None` variant, so ignoring them and
+// zero-initializing instead is ok.
+// `Option<&mut T>` never implements `Clone`, so there's no need for an impl of
+// `SpecFromElem`.
+
+unsafe impl<T: ?Sized> IsZero for Option<&T> {
+    #[inline]
+    fn is_zero(&self) -> bool {
+        self.is_none()
+    }
+}
+
+unsafe impl<T: ?Sized> IsZero for Option<Box<T>> {
+    #[inline]
+    fn is_zero(&self) -> bool {
+        self.is_none()
+    }
+}
+
+// `Option<num::NonZeroU32>` and similar have a representation guarantee that
+// they're the same size as the corresponding `u32` type, as well as a guarantee
+// that transmuting between `NonZeroU32` and `Option<num::NonZeroU32>` works.
+// While the documentation officially makes it UB to transmute from `None`,
+// we're the standard library so we can make extra inferences, and we know that
+// the only niche available to represent `None` is the one that's all zeros.
+
+macro_rules! impl_is_zero_option_of_nonzero {
+    ($($t:ident,)+) => {$(
+        unsafe impl IsZero for Option<core::num::$t> {
+            #[inline]
+            fn is_zero(&self) -> bool {
+                self.is_none()
+            }
+        }
+    )+};
+}
+
+impl_is_zero_option_of_nonzero!(
+    NonZeroU8,
+    NonZeroU16,
+    NonZeroU32,
+    NonZeroU64,
+    NonZeroU128,
+    NonZeroI8,
+    NonZeroI16,
+    NonZeroI32,
+    NonZeroI64,
+    NonZeroI128,
+    NonZeroUsize,
+    NonZeroIsize,
+);
diff --git a/rust/alloc/vec/mod.rs b/rust/alloc/vec/mod.rs
new file mode 100644
index 000000000000..4ae81b890fd9
--- /dev/null
+++ b/rust/alloc/vec/mod.rs
@@ -0,0 +1,3420 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! A contiguous growable array type with heap-allocated contents, written
+//! `Vec<T>`.
+//!
+//! Vectors have *O*(1) indexing, amortized *O*(1) push (to the end) and
+//! *O*(1) pop (from the end).
+//!
+//! Vectors ensure they never allocate more than `isize::MAX` bytes.
+//!
+//! # Examples
+//!
+//! You can explicitly create a [`Vec`] with [`Vec::new`]:
+//!
+//! ```
+//! let v: Vec<i32> = Vec::new();
+//! ```
+//!
+//! ...or by using the [`vec!`] macro:
+//!
+//! ```
+//! let v: Vec<i32> = vec![];
+//!
+//! let v = vec![1, 2, 3, 4, 5];
+//!
+//! let v = vec![0; 10]; // ten zeroes
+//! ```
+//!
+//! You can [`push`] values onto the end of a vector (which will grow the vector
+//! as needed):
+//!
+//! ```
+//! let mut v = vec![1, 2];
+//!
+//! v.push(3);
+//! ```
+//!
+//! Popping values works in much the same way:
+//!
+//! ```
+//! let mut v = vec![1, 2];
+//!
+//! let two = v.pop();
+//! ```
+//!
+//! Vectors also support indexing (through the [`Index`] and [`IndexMut`] traits):
+//!
+//! ```
+//! let mut v = vec![1, 2, 3];
+//! let three = v[2];
+//! v[1] = v[1] + 5;
+//! ```
+//!
+//! [`push`]: Vec::push
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+#[cfg(not(no_global_oom_handling))]
+use core::cmp;
+use core::cmp::Ordering;
+use core::convert::TryFrom;
+use core::fmt;
+use core::hash::{Hash, Hasher};
+use core::intrinsics::{arith_offset, assume};
+use core::iter;
+#[cfg(not(no_global_oom_handling))]
+use core::iter::FromIterator;
+use core::marker::PhantomData;
+use core::mem::{self, ManuallyDrop, MaybeUninit};
+use core::ops::{self, Index, IndexMut, Range, RangeBounds};
+use core::ptr::{self, NonNull};
+use core::slice::{self, SliceIndex};
+
+use crate::alloc::{Allocator, Global};
+use crate::borrow::{Cow, ToOwned};
+use crate::boxed::Box;
+use crate::collections::TryReserveError;
+use crate::raw_vec::RawVec;
+
+#[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+pub use self::drain_filter::DrainFilter;
+
+mod drain_filter;
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_splice", since = "1.21.0")]
+pub use self::splice::Splice;
+
+#[cfg(not(no_global_oom_handling))]
+mod splice;
+
+#[stable(feature = "drain", since = "1.6.0")]
+pub use self::drain::Drain;
+
+mod drain;
+
+#[cfg(not(no_global_oom_handling))]
+mod cow;
+
+#[cfg(not(no_global_oom_handling))]
+pub(crate) use self::in_place_collect::AsVecIntoIter;
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use self::into_iter::IntoIter;
+
+mod into_iter;
+
+#[cfg(not(no_global_oom_handling))]
+use self::is_zero::IsZero;
+
+mod is_zero;
+
+#[cfg(not(no_global_oom_handling))]
+mod in_place_collect;
+
+mod partial_eq;
+
+#[cfg(not(no_global_oom_handling))]
+use self::spec_from_elem::SpecFromElem;
+
+#[cfg(not(no_global_oom_handling))]
+mod spec_from_elem;
+
+use self::set_len_on_drop::SetLenOnDrop;
+
+mod set_len_on_drop;
+
+#[cfg(not(no_global_oom_handling))]
+use self::in_place_drop::InPlaceDrop;
+
+#[cfg(not(no_global_oom_handling))]
+mod in_place_drop;
+
+#[cfg(not(no_global_oom_handling))]
+use self::spec_from_iter_nested::SpecFromIterNested;
+
+#[cfg(not(no_global_oom_handling))]
+mod spec_from_iter_nested;
+
+#[cfg(not(no_global_oom_handling))]
+use self::spec_from_iter::SpecFromIter;
+
+#[cfg(not(no_global_oom_handling))]
+mod spec_from_iter;
+
+#[cfg(not(no_global_oom_handling))]
+use self::spec_extend::SpecExtend;
+
+use self::spec_extend::TrySpecExtend;
+
+mod spec_extend;
+
+/// A contiguous growable array type, written as `Vec<T>`, short for 'vector'.
+///
+/// # Examples
+///
+/// ```
+/// let mut vec = Vec::new();
+/// vec.push(1);
+/// vec.push(2);
+///
+/// assert_eq!(vec.len(), 2);
+/// assert_eq!(vec[0], 1);
+///
+/// assert_eq!(vec.pop(), Some(2));
+/// assert_eq!(vec.len(), 1);
+///
+/// vec[0] = 7;
+/// assert_eq!(vec[0], 7);
+///
+/// vec.extend([1, 2, 3].iter().copied());
+///
+/// for x in &vec {
+///     println!("{x}");
+/// }
+/// assert_eq!(vec, [7, 1, 2, 3]);
+/// ```
+///
+/// The [`vec!`] macro is provided for convenient initialization:
+///
+/// ```
+/// let mut vec1 = vec![1, 2, 3];
+/// vec1.push(4);
+/// let vec2 = Vec::from([1, 2, 3, 4]);
+/// assert_eq!(vec1, vec2);
+/// ```
+///
+/// It can also initialize each element of a `Vec<T>` with a given value.
+/// This may be more efficient than performing allocation and initialization
+/// in separate steps, especially when initializing a vector of zeros:
+///
+/// ```
+/// let vec = vec![0; 5];
+/// assert_eq!(vec, [0, 0, 0, 0, 0]);
+///
+/// // The following is equivalent, but potentially slower:
+/// let mut vec = Vec::with_capacity(5);
+/// vec.resize(5, 0);
+/// assert_eq!(vec, [0, 0, 0, 0, 0]);
+/// ```
+///
+/// For more information, see
+/// [Capacity and Reallocation](#capacity-and-reallocation).
+///
+/// Use a `Vec<T>` as an efficient stack:
+///
+/// ```
+/// let mut stack = Vec::new();
+///
+/// stack.push(1);
+/// stack.push(2);
+/// stack.push(3);
+///
+/// while let Some(top) = stack.pop() {
+///     // Prints 3, 2, 1
+///     println!("{top}");
+/// }
+/// ```
+///
+/// # Indexing
+///
+/// The `Vec` type allows to access values by index, because it implements the
+/// [`Index`] trait. An example will be more explicit:
+///
+/// ```
+/// let v = vec![0, 2, 4, 6];
+/// println!("{}", v[1]); // it will display '2'
+/// ```
+///
+/// However be careful: if you try to access an index which isn't in the `Vec`,
+/// your software will panic! You cannot do this:
+///
+/// ```should_panic
+/// let v = vec![0, 2, 4, 6];
+/// println!("{}", v[6]); // it will panic!
+/// ```
+///
+/// Use [`get`] and [`get_mut`] if you want to check whether the index is in
+/// the `Vec`.
+///
+/// # Slicing
+///
+/// A `Vec` can be mutable. On the other hand, slices are read-only objects.
+/// To get a [slice][prim@slice], use [`&`]. Example:
+///
+/// ```
+/// fn read_slice(slice: &[usize]) {
+///     // ...
+/// }
+///
+/// let v = vec![0, 1];
+/// read_slice(&v);
+///
+/// // ... and that's all!
+/// // you can also do it like this:
+/// let u: &[usize] = &v;
+/// // or like this:
+/// let u: &[_] = &v;
+/// ```
+///
+/// In Rust, it's more common to pass slices as arguments rather than vectors
+/// when you just want to provide read access. The same goes for [`String`] and
+/// [`&str`].
+///
+/// # Capacity and reallocation
+///
+/// The capacity of a vector is the amount of space allocated for any future
+/// elements that will be added onto the vector. This is not to be confused with
+/// the *length* of a vector, which specifies the number of actual elements
+/// within the vector. If a vector's length exceeds its capacity, its capacity
+/// will automatically be increased, but its elements will have to be
+/// reallocated.
+///
+/// For example, a vector with capacity 10 and length 0 would be an empty vector
+/// with space for 10 more elements. Pushing 10 or fewer elements onto the
+/// vector will not change its capacity or cause reallocation to occur. However,
+/// if the vector's length is increased to 11, it will have to reallocate, which
+/// can be slow. For this reason, it is recommended to use [`Vec::with_capacity`]
+/// whenever possible to specify how big the vector is expected to get.
+///
+/// # Guarantees
+///
+/// Due to its incredibly fundamental nature, `Vec` makes a lot of guarantees
+/// about its design. This ensures that it's as low-overhead as possible in
+/// the general case, and can be correctly manipulated in primitive ways
+/// by unsafe code. Note that these guarantees refer to an unqualified `Vec<T>`.
+/// If additional type parameters are added (e.g., to support custom allocators),
+/// overriding their defaults may change the behavior.
+///
+/// Most fundamentally, `Vec` is and always will be a (pointer, capacity, length)
+/// triplet. No more, no less. The order of these fields is completely
+/// unspecified, and you should use the appropriate methods to modify these.
+/// The pointer will never be null, so this type is null-pointer-optimized.
+///
+/// However, the pointer might not actually point to allocated memory. In particular,
+/// if you construct a `Vec` with capacity 0 via [`Vec::new`], [`vec![]`][`vec!`],
+/// [`Vec::with_capacity(0)`][`Vec::with_capacity`], or by calling [`shrink_to_fit`]
+/// on an empty Vec, it will not allocate memory. Similarly, if you store zero-sized
+/// types inside a `Vec`, it will not allocate space for them. *Note that in this case
+/// the `Vec` might not report a [`capacity`] of 0*. `Vec` will allocate if and only
+/// if <code>[mem::size_of::\<T>]\() * [capacity]\() > 0</code>. In general, `Vec`'s allocation
+/// details are very subtle --- if you intend to allocate memory using a `Vec`
+/// and use it for something else (either to pass to unsafe code, or to build your
+/// own memory-backed collection), be sure to deallocate this memory by using
+/// `from_raw_parts` to recover the `Vec` and then dropping it.
+///
+/// If a `Vec` *has* allocated memory, then the memory it points to is on the heap
+/// (as defined by the allocator Rust is configured to use by default), and its
+/// pointer points to [`len`] initialized, contiguous elements in order (what
+/// you would see if you coerced it to a slice), followed by <code>[capacity] - [len]</code>
+/// logically uninitialized, contiguous elements.
+///
+/// A vector containing the elements `'a'` and `'b'` with capacity 4 can be
+/// visualized as below. The top part is the `Vec` struct, it contains a
+/// pointer to the head of the allocation in the heap, length and capacity.
+/// The bottom part is the allocation on the heap, a contiguous memory block.
+///
+/// ```text
+///             ptr      len  capacity
+///        +--------+--------+--------+
+///        | 0x0123 |      2 |      4 |
+///        +--------+--------+--------+
+///             |
+///             v
+/// Heap   +--------+--------+--------+--------+
+///        |    'a' |    'b' | uninit | uninit |
+///        +--------+--------+--------+--------+
+/// ```
+///
+/// - **uninit** represents memory that is not initialized, see [`MaybeUninit`].
+/// - Note: the ABI is not stable and `Vec` makes no guarantees about its memory
+///   layout (including the order of fields).
+///
+/// `Vec` will never perform a "small optimization" where elements are actually
+/// stored on the stack for two reasons:
+///
+/// * It would make it more difficult for unsafe code to correctly manipulate
+///   a `Vec`. The contents of a `Vec` wouldn't have a stable address if it were
+///   only moved, and it would be more difficult to determine if a `Vec` had
+///   actually allocated memory.
+///
+/// * It would penalize the general case, incurring an additional branch
+///   on every access.
+///
+/// `Vec` will never automatically shrink itself, even if completely empty. This
+/// ensures no unnecessary allocations or deallocations occur. Emptying a `Vec`
+/// and then filling it back up to the same [`len`] should incur no calls to
+/// the allocator. If you wish to free up unused memory, use
+/// [`shrink_to_fit`] or [`shrink_to`].
+///
+/// [`push`] and [`insert`] will never (re)allocate if the reported capacity is
+/// sufficient. [`push`] and [`insert`] *will* (re)allocate if
+/// <code>[len] == [capacity]</code>. That is, the reported capacity is completely
+/// accurate, and can be relied on. It can even be used to manually free the memory
+/// allocated by a `Vec` if desired. Bulk insertion methods *may* reallocate, even
+/// when not necessary.
+///
+/// `Vec` does not guarantee any particular growth strategy when reallocating
+/// when full, nor when [`reserve`] is called. The current strategy is basic
+/// and it may prove desirable to use a non-constant growth factor. Whatever
+/// strategy is used will of course guarantee *O*(1) amortized [`push`].
+///
+/// `vec![x; n]`, `vec![a, b, c, d]`, and
+/// [`Vec::with_capacity(n)`][`Vec::with_capacity`], will all produce a `Vec`
+/// with exactly the requested capacity. If <code>[len] == [capacity]</code>,
+/// (as is the case for the [`vec!`] macro), then a `Vec<T>` can be converted to
+/// and from a [`Box<[T]>`][owned slice] without reallocating or moving the elements.
+///
+/// `Vec` will not specifically overwrite any data that is removed from it,
+/// but also won't specifically preserve it. Its uninitialized memory is
+/// scratch space that it may use however it wants. It will generally just do
+/// whatever is most efficient or otherwise easy to implement. Do not rely on
+/// removed data to be erased for security purposes. Even if you drop a `Vec`, its
+/// buffer may simply be reused by another allocation. Even if you zero a `Vec`'s memory
+/// first, that might not actually happen because the optimizer does not consider
+/// this a side-effect that must be preserved. There is one case which we will
+/// not break, however: using `unsafe` code to write to the excess capacity,
+/// and then increasing the length to match, is always valid.
+///
+/// Currently, `Vec` does not guarantee the order in which elements are dropped.
+/// The order has changed in the past and may change again.
+///
+/// [`get`]: ../../std/vec/struct.Vec.html#method.get
+/// [`get_mut`]: ../../std/vec/struct.Vec.html#method.get_mut
+/// [`String`]: crate::string::String
+/// [`&str`]: type@str
+/// [`shrink_to_fit`]: Vec::shrink_to_fit
+/// [`shrink_to`]: Vec::shrink_to
+/// [capacity]: Vec::capacity
+/// [`capacity`]: Vec::capacity
+/// [mem::size_of::\<T>]: core::mem::size_of
+/// [len]: Vec::len
+/// [`len`]: Vec::len
+/// [`push`]: Vec::push
+/// [`insert`]: Vec::insert
+/// [`reserve`]: Vec::reserve
+/// [`MaybeUninit`]: core::mem::MaybeUninit
+/// [owned slice]: Box
+#[stable(feature = "rust1", since = "1.0.0")]
+#[cfg_attr(not(test), rustc_diagnostic_item = "Vec")]
+#[rustc_insignificant_dtor]
+pub struct Vec<T, #[unstable(feature = "allocator_api", issue = "32838")] A: Allocator = Global> {
+    buf: RawVec<T, A>,
+    len: usize,
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Inherent methods
+////////////////////////////////////////////////////////////////////////////////
+
+impl<T> Vec<T> {
+    /// Constructs a new, empty `Vec<T>`.
+    ///
+    /// The vector will not allocate until elements are pushed onto it.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # #![allow(unused_mut)]
+    /// let mut vec: Vec<i32> = Vec::new();
+    /// ```
+    #[inline]
+    #[rustc_const_stable(feature = "const_vec_new", since = "1.39.0")]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use]
+    pub const fn new() -> Self {
+        Vec { buf: RawVec::NEW, len: 0 }
+    }
+
+    /// Constructs a new, empty `Vec<T>` with the specified capacity.
+    ///
+    /// The vector will be able to hold exactly `capacity` elements without
+    /// reallocating. If `capacity` is 0, the vector will not allocate.
+    ///
+    /// It is important to note that although the returned vector has the
+    /// *capacity* specified, the vector will have a zero *length*. For an
+    /// explanation of the difference between length and capacity, see
+    /// *[Capacity and reallocation]*.
+    ///
+    /// [Capacity and reallocation]: #capacity-and-reallocation
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity exceeds `isize::MAX` bytes.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = Vec::with_capacity(10);
+    ///
+    /// // The vector contains no items, even though it has capacity for more
+    /// assert_eq!(vec.len(), 0);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // These are all done without reallocating...
+    /// for i in 0..10 {
+    ///     vec.push(i);
+    /// }
+    /// assert_eq!(vec.len(), 10);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // ...but this may make the vector reallocate
+    /// vec.push(11);
+    /// assert_eq!(vec.len(), 11);
+    /// assert!(vec.capacity() >= 11);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[must_use]
+    pub fn with_capacity(capacity: usize) -> Self {
+        Self::with_capacity_in(capacity, Global)
+    }
+
+    /// Tries to construct a new, empty `Vec<T>` with the specified capacity.
+    ///
+    /// The vector will be able to hold exactly `capacity` elements without
+    /// reallocating. If `capacity` is 0, the vector will not allocate.
+    ///
+    /// It is important to note that although the returned vector has the
+    /// *capacity* specified, the vector will have a zero *length*. For an
+    /// explanation of the difference between length and capacity, see
+    /// *[Capacity and reallocation]*.
+    ///
+    /// [Capacity and reallocation]: #capacity-and-reallocation
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = Vec::try_with_capacity(10).unwrap();
+    ///
+    /// // The vector contains no items, even though it has capacity for more
+    /// assert_eq!(vec.len(), 0);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // These are all done without reallocating...
+    /// for i in 0..10 {
+    ///     vec.push(i);
+    /// }
+    /// assert_eq!(vec.len(), 10);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // ...but this may make the vector reallocate
+    /// vec.push(11);
+    /// assert_eq!(vec.len(), 11);
+    /// assert!(vec.capacity() >= 11);
+    ///
+    /// let mut result = Vec::try_with_capacity(usize::MAX);
+    /// assert!(result.is_err());
+    /// ```
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_with_capacity(capacity: usize) -> Result<Self, TryReserveError> {
+        Self::try_with_capacity_in(capacity, Global)
+    }
+
+    /// Creates a `Vec<T>` directly from the raw components of another vector.
+    ///
+    /// # Safety
+    ///
+    /// This is highly unsafe, due to the number of invariants that aren't
+    /// checked:
+    ///
+    /// * `ptr` needs to have been previously allocated via [`String`]/`Vec<T>`
+    ///   (at least, it's highly likely to be incorrect if it wasn't).
+    /// * `T` needs to have the same alignment as what `ptr` was allocated with.
+    ///   (`T` having a less strict alignment is not sufficient, the alignment really
+    ///   needs to be equal to satisfy the [`dealloc`] requirement that memory must be
+    ///   allocated and deallocated with the same layout.)
+    /// * The size of `T` times the `capacity` (ie. the allocated size in bytes) needs
+    ///   to be the same size as the pointer was allocated with. (Because similar to
+    ///   alignment, [`dealloc`] must be called with the same layout `size`.)
+    /// * `length` needs to be less than or equal to `capacity`.
+    ///
+    /// Violating these may cause problems like corrupting the allocator's
+    /// internal data structures. For example it is normally **not** safe
+    /// to build a `Vec<u8>` from a pointer to a C `char` array with length
+    /// `size_t`, doing so is only safe if the array was initially allocated by
+    /// a `Vec` or `String`.
+    /// It's also not safe to build one from a `Vec<u16>` and its length, because
+    /// the allocator cares about the alignment, and these two types have different
+    /// alignments. The buffer was allocated with alignment 2 (for `u16`), but after
+    /// turning it into a `Vec<u8>` it'll be deallocated with alignment 1. To avoid
+    /// these issues, it is often preferable to do casting/transmuting using
+    /// [`slice::from_raw_parts`] instead.
+    ///
+    /// The ownership of `ptr` is effectively transferred to the
+    /// `Vec<T>` which may then deallocate, reallocate or change the
+    /// contents of memory pointed to by the pointer at will. Ensure
+    /// that nothing else uses the pointer after calling this
+    /// function.
+    ///
+    /// [`String`]: crate::string::String
+    /// [`dealloc`]: crate::alloc::GlobalAlloc::dealloc
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ptr;
+    /// use std::mem;
+    ///
+    /// let v = vec![1, 2, 3];
+    ///
+    // FIXME Update this when vec_into_raw_parts is stabilized
+    /// // Prevent running `v`'s destructor so we are in complete control
+    /// // of the allocation.
+    /// let mut v = mem::ManuallyDrop::new(v);
+    ///
+    /// // Pull out the various important pieces of information about `v`
+    /// let p = v.as_mut_ptr();
+    /// let len = v.len();
+    /// let cap = v.capacity();
+    ///
+    /// unsafe {
+    ///     // Overwrite memory with 4, 5, 6
+    ///     for i in 0..len as isize {
+    ///         ptr::write(p.offset(i), 4 + i);
+    ///     }
+    ///
+    ///     // Put everything back together into a Vec
+    ///     let rebuilt = Vec::from_raw_parts(p, len, cap);
+    ///     assert_eq!(rebuilt, [4, 5, 6]);
+    /// }
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub unsafe fn from_raw_parts(ptr: *mut T, length: usize, capacity: usize) -> Self {
+        unsafe { Self::from_raw_parts_in(ptr, length, capacity, Global) }
+    }
+}
+
+impl<T, A: Allocator> Vec<T, A> {
+    /// Constructs a new, empty `Vec<T, A>`.
+    ///
+    /// The vector will not allocate until elements are pushed onto it.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// # #[allow(unused_mut)]
+    /// let mut vec: Vec<i32, _> = Vec::new_in(System);
+    /// ```
+    #[inline]
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    pub const fn new_in(alloc: A) -> Self {
+        Vec { buf: RawVec::new_in(alloc), len: 0 }
+    }
+
+    /// Constructs a new, empty `Vec<T, A>` with the specified capacity with the provided
+    /// allocator.
+    ///
+    /// The vector will be able to hold exactly `capacity` elements without
+    /// reallocating. If `capacity` is 0, the vector will not allocate.
+    ///
+    /// It is important to note that although the returned vector has the
+    /// *capacity* specified, the vector will have a zero *length*. For an
+    /// explanation of the difference between length and capacity, see
+    /// *[Capacity and reallocation]*.
+    ///
+    /// [Capacity and reallocation]: #capacity-and-reallocation
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity exceeds `isize::MAX` bytes.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let mut vec = Vec::with_capacity_in(10, System);
+    ///
+    /// // The vector contains no items, even though it has capacity for more
+    /// assert_eq!(vec.len(), 0);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // These are all done without reallocating...
+    /// for i in 0..10 {
+    ///     vec.push(i);
+    /// }
+    /// assert_eq!(vec.len(), 10);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // ...but this may make the vector reallocate
+    /// vec.push(11);
+    /// assert_eq!(vec.len(), 11);
+    /// assert!(vec.capacity() >= 11);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    pub fn with_capacity_in(capacity: usize, alloc: A) -> Self {
+        Vec { buf: RawVec::with_capacity_in(capacity, alloc), len: 0 }
+    }
+
+    /// Tries to construct a new, empty `Vec<T, A>` with the specified capacity
+    /// with the provided allocator.
+    ///
+    /// The vector will be able to hold exactly `capacity` elements without
+    /// reallocating. If `capacity` is 0, the vector will not allocate.
+    ///
+    /// It is important to note that although the returned vector has the
+    /// *capacity* specified, the vector will have a zero *length*. For an
+    /// explanation of the difference between length and capacity, see
+    /// *[Capacity and reallocation]*.
+    ///
+    /// [Capacity and reallocation]: #capacity-and-reallocation
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let mut vec = Vec::try_with_capacity_in(10, System).unwrap();
+    ///
+    /// // The vector contains no items, even though it has capacity for more
+    /// assert_eq!(vec.len(), 0);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // These are all done without reallocating...
+    /// for i in 0..10 {
+    ///     vec.push(i);
+    /// }
+    /// assert_eq!(vec.len(), 10);
+    /// assert_eq!(vec.capacity(), 10);
+    ///
+    /// // ...but this may make the vector reallocate
+    /// vec.push(11);
+    /// assert_eq!(vec.len(), 11);
+    /// assert!(vec.capacity() >= 11);
+    ///
+    /// let mut result = Vec::try_with_capacity_in(usize::MAX, System);
+    /// assert!(result.is_err());
+    /// ```
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_with_capacity_in(capacity: usize, alloc: A) -> Result<Self, TryReserveError> {
+        Ok(Vec { buf: RawVec::try_with_capacity_in(capacity, alloc)?, len: 0 })
+    }
+
+    /// Creates a `Vec<T, A>` directly from the raw components of another vector.
+    ///
+    /// # Safety
+    ///
+    /// This is highly unsafe, due to the number of invariants that aren't
+    /// checked:
+    ///
+    /// * `ptr` needs to have been previously allocated via [`String`]/`Vec<T>`
+    ///   (at least, it's highly likely to be incorrect if it wasn't).
+    /// * `T` needs to have the same size and alignment as what `ptr` was allocated with.
+    ///   (`T` having a less strict alignment is not sufficient, the alignment really
+    ///   needs to be equal to satisfy the [`dealloc`] requirement that memory must be
+    ///   allocated and deallocated with the same layout.)
+    /// * `length` needs to be less than or equal to `capacity`.
+    /// * `capacity` needs to be the capacity that the pointer was allocated with.
+    ///
+    /// Violating these may cause problems like corrupting the allocator's
+    /// internal data structures. For example it is **not** safe
+    /// to build a `Vec<u8>` from a pointer to a C `char` array with length `size_t`.
+    /// It's also not safe to build one from a `Vec<u16>` and its length, because
+    /// the allocator cares about the alignment, and these two types have different
+    /// alignments. The buffer was allocated with alignment 2 (for `u16`), but after
+    /// turning it into a `Vec<u8>` it'll be deallocated with alignment 1.
+    ///
+    /// The ownership of `ptr` is effectively transferred to the
+    /// `Vec<T>` which may then deallocate, reallocate or change the
+    /// contents of memory pointed to by the pointer at will. Ensure
+    /// that nothing else uses the pointer after calling this
+    /// function.
+    ///
+    /// [`String`]: crate::string::String
+    /// [`dealloc`]: crate::alloc::GlobalAlloc::dealloc
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// use std::ptr;
+    /// use std::mem;
+    ///
+    /// let mut v = Vec::with_capacity_in(3, System);
+    /// v.push(1);
+    /// v.push(2);
+    /// v.push(3);
+    ///
+    // FIXME Update this when vec_into_raw_parts is stabilized
+    /// // Prevent running `v`'s destructor so we are in complete control
+    /// // of the allocation.
+    /// let mut v = mem::ManuallyDrop::new(v);
+    ///
+    /// // Pull out the various important pieces of information about `v`
+    /// let p = v.as_mut_ptr();
+    /// let len = v.len();
+    /// let cap = v.capacity();
+    /// let alloc = v.allocator();
+    ///
+    /// unsafe {
+    ///     // Overwrite memory with 4, 5, 6
+    ///     for i in 0..len as isize {
+    ///         ptr::write(p.offset(i), 4 + i);
+    ///     }
+    ///
+    ///     // Put everything back together into a Vec
+    ///     let rebuilt = Vec::from_raw_parts_in(p, len, cap, alloc.clone());
+    ///     assert_eq!(rebuilt, [4, 5, 6]);
+    /// }
+    /// ```
+    #[inline]
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    pub unsafe fn from_raw_parts_in(ptr: *mut T, length: usize, capacity: usize, alloc: A) -> Self {
+        unsafe { Vec { buf: RawVec::from_raw_parts_in(ptr, capacity, alloc), len: length } }
+    }
+
+    /// Decomposes a `Vec<T>` into its raw components.
+    ///
+    /// Returns the raw pointer to the underlying data, the length of
+    /// the vector (in elements), and the allocated capacity of the
+    /// data (in elements). These are the same arguments in the same
+    /// order as the arguments to [`from_raw_parts`].
+    ///
+    /// After calling this function, the caller is responsible for the
+    /// memory previously managed by the `Vec`. The only way to do
+    /// this is to convert the raw pointer, length, and capacity back
+    /// into a `Vec` with the [`from_raw_parts`] function, allowing
+    /// the destructor to perform the cleanup.
+    ///
+    /// [`from_raw_parts`]: Vec::from_raw_parts
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(vec_into_raw_parts)]
+    /// let v: Vec<i32> = vec![-1, 0, 1];
+    ///
+    /// let (ptr, len, cap) = v.into_raw_parts();
+    ///
+    /// let rebuilt = unsafe {
+    ///     // We can now make changes to the components, such as
+    ///     // transmuting the raw pointer to a compatible type.
+    ///     let ptr = ptr as *mut u32;
+    ///
+    ///     Vec::from_raw_parts(ptr, len, cap)
+    /// };
+    /// assert_eq!(rebuilt, [4294967295, 0, 1]);
+    /// ```
+    #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
+    pub fn into_raw_parts(self) -> (*mut T, usize, usize) {
+        let mut me = ManuallyDrop::new(self);
+        (me.as_mut_ptr(), me.len(), me.capacity())
+    }
+
+    /// Decomposes a `Vec<T>` into its raw components.
+    ///
+    /// Returns the raw pointer to the underlying data, the length of the vector (in elements),
+    /// the allocated capacity of the data (in elements), and the allocator. These are the same
+    /// arguments in the same order as the arguments to [`from_raw_parts_in`].
+    ///
+    /// After calling this function, the caller is responsible for the
+    /// memory previously managed by the `Vec`. The only way to do
+    /// this is to convert the raw pointer, length, and capacity back
+    /// into a `Vec` with the [`from_raw_parts_in`] function, allowing
+    /// the destructor to perform the cleanup.
+    ///
+    /// [`from_raw_parts_in`]: Vec::from_raw_parts_in
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(allocator_api, vec_into_raw_parts)]
+    ///
+    /// use std::alloc::System;
+    ///
+    /// let mut v: Vec<i32, System> = Vec::new_in(System);
+    /// v.push(-1);
+    /// v.push(0);
+    /// v.push(1);
+    ///
+    /// let (ptr, len, cap, alloc) = v.into_raw_parts_with_alloc();
+    ///
+    /// let rebuilt = unsafe {
+    ///     // We can now make changes to the components, such as
+    ///     // transmuting the raw pointer to a compatible type.
+    ///     let ptr = ptr as *mut u32;
+    ///
+    ///     Vec::from_raw_parts_in(ptr, len, cap, alloc)
+    /// };
+    /// assert_eq!(rebuilt, [4294967295, 0, 1]);
+    /// ```
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    // #[unstable(feature = "vec_into_raw_parts", reason = "new API", issue = "65816")]
+    pub fn into_raw_parts_with_alloc(self) -> (*mut T, usize, usize, A) {
+        let mut me = ManuallyDrop::new(self);
+        let len = me.len();
+        let capacity = me.capacity();
+        let ptr = me.as_mut_ptr();
+        let alloc = unsafe { ptr::read(me.allocator()) };
+        (ptr, len, capacity, alloc)
+    }
+
+    /// Returns the number of elements the vector can hold without
+    /// reallocating.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let vec: Vec<i32> = Vec::with_capacity(10);
+    /// assert_eq!(vec.capacity(), 10);
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn capacity(&self) -> usize {
+        self.buf.capacity()
+    }
+
+    /// Reserves capacity for at least `additional` more elements to be inserted
+    /// in the given `Vec<T>`. The collection may reserve more space to avoid
+    /// frequent reallocations. After calling `reserve`, capacity will be
+    /// greater than or equal to `self.len() + additional`. Does nothing if
+    /// capacity is already sufficient.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity exceeds `isize::MAX` bytes.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1];
+    /// vec.reserve(10);
+    /// assert!(vec.capacity() >= 11);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn reserve(&mut self, additional: usize) {
+        self.buf.reserve(self.len, additional);
+    }
+
+    /// Reserves the minimum capacity for exactly `additional` more elements to
+    /// be inserted in the given `Vec<T>`. After calling `reserve_exact`,
+    /// capacity will be greater than or equal to `self.len() + additional`.
+    /// Does nothing if the capacity is already sufficient.
+    ///
+    /// Note that the allocator may give the collection more space than it
+    /// requests. Therefore, capacity can not be relied upon to be precisely
+    /// minimal. Prefer [`reserve`] if future insertions are expected.
+    ///
+    /// [`reserve`]: Vec::reserve
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity exceeds `isize::MAX` bytes.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1];
+    /// vec.reserve_exact(10);
+    /// assert!(vec.capacity() >= 11);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn reserve_exact(&mut self, additional: usize) {
+        self.buf.reserve_exact(self.len, additional);
+    }
+
+    /// Tries to reserve capacity for at least `additional` more elements to be inserted
+    /// in the given `Vec<T>`. The collection may reserve more space to avoid
+    /// frequent reallocations. After calling `try_reserve`, capacity will be
+    /// greater than or equal to `self.len() + additional`. Does nothing if
+    /// capacity is already sufficient.
+    ///
+    /// # Errors
+    ///
+    /// If the capacity overflows, or the allocator reports a failure, then an error
+    /// is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::collections::TryReserveError;
+    ///
+    /// fn process_data(data: &[u32]) -> Result<Vec<u32>, TryReserveError> {
+    ///     let mut output = Vec::new();
+    ///
+    ///     // Pre-reserve the memory, exiting if we can't
+    ///     output.try_reserve(data.len())?;
+    ///
+    ///     // Now we know this can't OOM in the middle of our complex work
+    ///     output.extend(data.iter().map(|&val| {
+    ///         val * 2 + 5 // very complicated
+    ///     }));
+    ///
+    ///     Ok(output)
+    /// }
+    /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
+    /// ```
+    #[stable(feature = "try_reserve", since = "1.57.0")]
+    pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
+        self.buf.try_reserve(self.len, additional)
+    }
+
+    /// Tries to reserve the minimum capacity for exactly `additional`
+    /// elements to be inserted in the given `Vec<T>`. After calling
+    /// `try_reserve_exact`, capacity will be greater than or equal to
+    /// `self.len() + additional` if it returns `Ok(())`.
+    /// Does nothing if the capacity is already sufficient.
+    ///
+    /// Note that the allocator may give the collection more space than it
+    /// requests. Therefore, capacity can not be relied upon to be precisely
+    /// minimal. Prefer [`try_reserve`] if future insertions are expected.
+    ///
+    /// [`try_reserve`]: Vec::try_reserve
+    ///
+    /// # Errors
+    ///
+    /// If the capacity overflows, or the allocator reports a failure, then an error
+    /// is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::collections::TryReserveError;
+    ///
+    /// fn process_data(data: &[u32]) -> Result<Vec<u32>, TryReserveError> {
+    ///     let mut output = Vec::new();
+    ///
+    ///     // Pre-reserve the memory, exiting if we can't
+    ///     output.try_reserve_exact(data.len())?;
+    ///
+    ///     // Now we know this can't OOM in the middle of our complex work
+    ///     output.extend(data.iter().map(|&val| {
+    ///         val * 2 + 5 // very complicated
+    ///     }));
+    ///
+    ///     Ok(output)
+    /// }
+    /// # process_data(&[1, 2, 3]).expect("why is the test harness OOMing on 12 bytes?");
+    /// ```
+    #[stable(feature = "try_reserve", since = "1.57.0")]
+    pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> {
+        self.buf.try_reserve_exact(self.len, additional)
+    }
+
+    /// Shrinks the capacity of the vector as much as possible.
+    ///
+    /// It will drop down as close as possible to the length but the allocator
+    /// may still inform the vector that there is space for a few more elements.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = Vec::with_capacity(10);
+    /// vec.extend([1, 2, 3]);
+    /// assert_eq!(vec.capacity(), 10);
+    /// vec.shrink_to_fit();
+    /// assert!(vec.capacity() >= 3);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn shrink_to_fit(&mut self) {
+        // The capacity is never less than the length, and there's nothing to do when
+        // they are equal, so we can avoid the panic case in `RawVec::shrink_to_fit`
+        // by only calling it with a greater capacity.
+        if self.capacity() > self.len {
+            self.buf.shrink_to_fit(self.len);
+        }
+    }
+
+    /// Tries to shrink the capacity of the vector as much as possible.
+    ///
+    /// It will drop down as close as possible to the length but the allocator
+    /// may still inform the vector that there is space for a few more elements.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = Vec::with_capacity(10);
+    /// vec.extend([1, 2, 3]);
+    /// assert_eq!(vec.capacity(), 10);
+    /// vec.try_shrink_to_fit().unwrap();
+    /// assert!(vec.capacity() >= 3);
+    /// ```
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_shrink_to_fit(&mut self) -> Result<(), TryReserveError> {
+        // The capacity is never less than the length, and there's nothing to do when
+        // they are equal, so we can avoid the panic case in `RawVec::try_shrink_to_fit`
+        // by only calling it with a greater capacity.
+        if self.capacity() <= self.len {
+            return Ok(());
+        }
+
+        self.buf.try_shrink_to_fit(self.len)
+    }
+
+    /// Shrinks the capacity of the vector with a lower bound.
+    ///
+    /// The capacity will remain at least as large as both the length
+    /// and the supplied value.
+    ///
+    /// If the current capacity is less than the lower limit, this is a no-op.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = Vec::with_capacity(10);
+    /// vec.extend([1, 2, 3]);
+    /// assert_eq!(vec.capacity(), 10);
+    /// vec.shrink_to(4);
+    /// assert!(vec.capacity() >= 4);
+    /// vec.shrink_to(0);
+    /// assert!(vec.capacity() >= 3);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "shrink_to", since = "1.56.0")]
+    pub fn shrink_to(&mut self, min_capacity: usize) {
+        if self.capacity() > min_capacity {
+            self.buf.shrink_to_fit(cmp::max(self.len, min_capacity));
+        }
+    }
+
+    /// Converts the vector into [`Box<[T]>`][owned slice].
+    ///
+    /// Note that this will drop any excess capacity.
+    ///
+    /// [owned slice]: Box
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = vec![1, 2, 3];
+    ///
+    /// let slice = v.into_boxed_slice();
+    /// ```
+    ///
+    /// Any excess capacity is removed:
+    ///
+    /// ```
+    /// let mut vec = Vec::with_capacity(10);
+    /// vec.extend([1, 2, 3]);
+    ///
+    /// assert_eq!(vec.capacity(), 10);
+    /// let slice = vec.into_boxed_slice();
+    /// assert_eq!(slice.into_vec().capacity(), 3);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn into_boxed_slice(mut self) -> Box<[T], A> {
+        unsafe {
+            self.shrink_to_fit();
+            let me = ManuallyDrop::new(self);
+            let buf = ptr::read(&me.buf);
+            let len = me.len();
+            buf.into_box(len).assume_init()
+        }
+    }
+
+    /// Tries to convert the vector into [`Box<[T]>`][owned slice].
+    ///
+    /// Note that this will drop any excess capacity.
+    ///
+    /// [owned slice]: Box
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = vec![1, 2, 3];
+    ///
+    /// let slice = v.try_into_boxed_slice().unwrap();
+    /// ```
+    ///
+    /// Any excess capacity is removed:
+    ///
+    /// ```
+    /// let mut vec = Vec::with_capacity(10);
+    /// vec.extend([1, 2, 3]);
+    ///
+    /// assert_eq!(vec.capacity(), 10);
+    /// let slice = vec.try_into_boxed_slice().unwrap();
+    /// assert_eq!(slice.into_vec().capacity(), 3);
+    /// ```
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_into_boxed_slice(mut self) -> Result<Box<[T], A>, TryReserveError> {
+        unsafe {
+            self.try_shrink_to_fit()?;
+            let me = ManuallyDrop::new(self);
+            let buf = ptr::read(&me.buf);
+            let len = me.len();
+            Ok(buf.into_box(len).assume_init())
+        }
+    }
+
+    /// Shortens the vector, keeping the first `len` elements and dropping
+    /// the rest.
+    ///
+    /// If `len` is greater than the vector's current length, this has no
+    /// effect.
+    ///
+    /// The [`drain`] method can emulate `truncate`, but causes the excess
+    /// elements to be returned instead of dropped.
+    ///
+    /// Note that this method has no effect on the allocated capacity
+    /// of the vector.
+    ///
+    /// # Examples
+    ///
+    /// Truncating a five element vector to two elements:
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3, 4, 5];
+    /// vec.truncate(2);
+    /// assert_eq!(vec, [1, 2]);
+    /// ```
+    ///
+    /// No truncation occurs when `len` is greater than the vector's current
+    /// length:
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3];
+    /// vec.truncate(8);
+    /// assert_eq!(vec, [1, 2, 3]);
+    /// ```
+    ///
+    /// Truncating when `len == 0` is equivalent to calling the [`clear`]
+    /// method.
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3];
+    /// vec.truncate(0);
+    /// assert_eq!(vec, []);
+    /// ```
+    ///
+    /// [`clear`]: Vec::clear
+    /// [`drain`]: Vec::drain
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn truncate(&mut self, len: usize) {
+        // This is safe because:
+        //
+        // * the slice passed to `drop_in_place` is valid; the `len > self.len`
+        //   case avoids creating an invalid slice, and
+        // * the `len` of the vector is shrunk before calling `drop_in_place`,
+        //   such that no value will be dropped twice in case `drop_in_place`
+        //   were to panic once (if it panics twice, the program aborts).
+        unsafe {
+            // Note: It's intentional that this is `>` and not `>=`.
+            //       Changing it to `>=` has negative performance
+            //       implications in some cases. See #78884 for more.
+            if len > self.len {
+                return;
+            }
+            let remaining_len = self.len - len;
+            let s = ptr::slice_from_raw_parts_mut(self.as_mut_ptr().add(len), remaining_len);
+            self.len = len;
+            ptr::drop_in_place(s);
+        }
+    }
+
+    /// Extracts a slice containing the entire vector.
+    ///
+    /// Equivalent to `&s[..]`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{self, Write};
+    /// let buffer = vec![1, 2, 3, 5, 8];
+    /// io::sink().write(buffer.as_slice()).unwrap();
+    /// ```
+    #[inline]
+    #[stable(feature = "vec_as_slice", since = "1.7.0")]
+    pub fn as_slice(&self) -> &[T] {
+        self
+    }
+
+    /// Extracts a mutable slice of the entire vector.
+    ///
+    /// Equivalent to `&mut s[..]`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::io::{self, Read};
+    /// let mut buffer = vec![0; 3];
+    /// io::repeat(0b101).read_exact(buffer.as_mut_slice()).unwrap();
+    /// ```
+    #[inline]
+    #[stable(feature = "vec_as_slice", since = "1.7.0")]
+    pub fn as_mut_slice(&mut self) -> &mut [T] {
+        self
+    }
+
+    /// Returns a raw pointer to the vector's buffer.
+    ///
+    /// The caller must ensure that the vector outlives the pointer this
+    /// function returns, or else it will end up pointing to garbage.
+    /// Modifying the vector may cause its buffer to be reallocated,
+    /// which would also make any pointers to it invalid.
+    ///
+    /// The caller must also ensure that the memory the pointer (non-transitively) points to
+    /// is never written to (except inside an `UnsafeCell`) using this pointer or any pointer
+    /// derived from it. If you need to mutate the contents of the slice, use [`as_mut_ptr`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let x = vec![1, 2, 4];
+    /// let x_ptr = x.as_ptr();
+    ///
+    /// unsafe {
+    ///     for i in 0..x.len() {
+    ///         assert_eq!(*x_ptr.add(i), 1 << i);
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// [`as_mut_ptr`]: Vec::as_mut_ptr
+    #[stable(feature = "vec_as_ptr", since = "1.37.0")]
+    #[inline]
+    pub fn as_ptr(&self) -> *const T {
+        // We shadow the slice method of the same name to avoid going through
+        // `deref`, which creates an intermediate reference.
+        let ptr = self.buf.ptr();
+        unsafe {
+            assume(!ptr.is_null());
+        }
+        ptr
+    }
+
+    /// Returns an unsafe mutable pointer to the vector's buffer.
+    ///
+    /// The caller must ensure that the vector outlives the pointer this
+    /// function returns, or else it will end up pointing to garbage.
+    /// Modifying the vector may cause its buffer to be reallocated,
+    /// which would also make any pointers to it invalid.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// // Allocate vector big enough for 4 elements.
+    /// let size = 4;
+    /// let mut x: Vec<i32> = Vec::with_capacity(size);
+    /// let x_ptr = x.as_mut_ptr();
+    ///
+    /// // Initialize elements via raw pointer writes, then set length.
+    /// unsafe {
+    ///     for i in 0..size {
+    ///         *x_ptr.add(i) = i as i32;
+    ///     }
+    ///     x.set_len(size);
+    /// }
+    /// assert_eq!(&*x, &[0, 1, 2, 3]);
+    /// ```
+    #[stable(feature = "vec_as_ptr", since = "1.37.0")]
+    #[inline]
+    pub fn as_mut_ptr(&mut self) -> *mut T {
+        // We shadow the slice method of the same name to avoid going through
+        // `deref_mut`, which creates an intermediate reference.
+        let ptr = self.buf.ptr();
+        unsafe {
+            assume(!ptr.is_null());
+        }
+        ptr
+    }
+
+    /// Returns a reference to the underlying allocator.
+    #[unstable(feature = "allocator_api", issue = "32838")]
+    #[inline]
+    pub fn allocator(&self) -> &A {
+        self.buf.allocator()
+    }
+
+    /// Forces the length of the vector to `new_len`.
+    ///
+    /// This is a low-level operation that maintains none of the normal
+    /// invariants of the type. Normally changing the length of a vector
+    /// is done using one of the safe operations instead, such as
+    /// [`truncate`], [`resize`], [`extend`], or [`clear`].
+    ///
+    /// [`truncate`]: Vec::truncate
+    /// [`resize`]: Vec::resize
+    /// [`extend`]: Extend::extend
+    /// [`clear`]: Vec::clear
+    ///
+    /// # Safety
+    ///
+    /// - `new_len` must be less than or equal to [`capacity()`].
+    /// - The elements at `old_len..new_len` must be initialized.
+    ///
+    /// [`capacity()`]: Vec::capacity
+    ///
+    /// # Examples
+    ///
+    /// This method can be useful for situations in which the vector
+    /// is serving as a buffer for other code, particularly over FFI:
+    ///
+    /// ```no_run
+    /// # #![allow(dead_code)]
+    /// # // This is just a minimal skeleton for the doc example;
+    /// # // don't use this as a starting point for a real library.
+    /// # pub struct StreamWrapper { strm: *mut std::ffi::c_void }
+    /// # const Z_OK: i32 = 0;
+    /// # extern "C" {
+    /// #     fn deflateGetDictionary(
+    /// #         strm: *mut std::ffi::c_void,
+    /// #         dictionary: *mut u8,
+    /// #         dictLength: *mut usize,
+    /// #     ) -> i32;
+    /// # }
+    /// # impl StreamWrapper {
+    /// pub fn get_dictionary(&self) -> Option<Vec<u8>> {
+    ///     // Per the FFI method's docs, "32768 bytes is always enough".
+    ///     let mut dict = Vec::with_capacity(32_768);
+    ///     let mut dict_length = 0;
+    ///     // SAFETY: When `deflateGetDictionary` returns `Z_OK`, it holds that:
+    ///     // 1. `dict_length` elements were initialized.
+    ///     // 2. `dict_length` <= the capacity (32_768)
+    ///     // which makes `set_len` safe to call.
+    ///     unsafe {
+    ///         // Make the FFI call...
+    ///         let r = deflateGetDictionary(self.strm, dict.as_mut_ptr(), &mut dict_length);
+    ///         if r == Z_OK {
+    ///             // ...and update the length to what was initialized.
+    ///             dict.set_len(dict_length);
+    ///             Some(dict)
+    ///         } else {
+    ///             None
+    ///         }
+    ///     }
+    /// }
+    /// # }
+    /// ```
+    ///
+    /// While the following example is sound, there is a memory leak since
+    /// the inner vectors were not freed prior to the `set_len` call:
+    ///
+    /// ```
+    /// let mut vec = vec![vec![1, 0, 0],
+    ///                    vec![0, 1, 0],
+    ///                    vec![0, 0, 1]];
+    /// // SAFETY:
+    /// // 1. `old_len..0` is empty so no elements need to be initialized.
+    /// // 2. `0 <= capacity` always holds whatever `capacity` is.
+    /// unsafe {
+    ///     vec.set_len(0);
+    /// }
+    /// ```
+    ///
+    /// Normally, here, one would use [`clear`] instead to correctly drop
+    /// the contents and thus not leak memory.
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub unsafe fn set_len(&mut self, new_len: usize) {
+        debug_assert!(new_len <= self.capacity());
+
+        self.len = new_len;
+    }
+
+    /// Removes an element from the vector and returns it.
+    ///
+    /// The removed element is replaced by the last element of the vector.
+    ///
+    /// This does not preserve ordering, but is *O*(1).
+    /// If you need to preserve the element order, use [`remove`] instead.
+    ///
+    /// [`remove`]: Vec::remove
+    ///
+    /// # Panics
+    ///
+    /// Panics if `index` is out of bounds.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = vec!["foo", "bar", "baz", "qux"];
+    ///
+    /// assert_eq!(v.swap_remove(1), "bar");
+    /// assert_eq!(v, ["foo", "qux", "baz"]);
+    ///
+    /// assert_eq!(v.swap_remove(0), "foo");
+    /// assert_eq!(v, ["baz", "qux"]);
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn swap_remove(&mut self, index: usize) -> T {
+        #[cold]
+        #[inline(never)]
+        fn assert_failed(index: usize, len: usize) -> ! {
+            panic!("swap_remove index (is {index}) should be < len (is {len})");
+        }
+
+        let len = self.len();
+        if index >= len {
+            assert_failed(index, len);
+        }
+        unsafe {
+            // We replace self[index] with the last element. Note that if the
+            // bounds check above succeeds there must be a last element (which
+            // can be self[index] itself).
+            let value = ptr::read(self.as_ptr().add(index));
+            let base_ptr = self.as_mut_ptr();
+            ptr::copy(base_ptr.add(len - 1), base_ptr.add(index), 1);
+            self.set_len(len - 1);
+            value
+        }
+    }
+
+    /// Inserts an element at position `index` within the vector, shifting all
+    /// elements after it to the right.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `index > len`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3];
+    /// vec.insert(1, 4);
+    /// assert_eq!(vec, [1, 4, 2, 3]);
+    /// vec.insert(4, 5);
+    /// assert_eq!(vec, [1, 4, 2, 3, 5]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn insert(&mut self, index: usize, element: T) {
+        #[cold]
+        #[inline(never)]
+        fn assert_failed(index: usize, len: usize) -> ! {
+            panic!("insertion index (is {index}) should be <= len (is {len})");
+        }
+
+        let len = self.len();
+        if index > len {
+            assert_failed(index, len);
+        }
+
+        // space for the new element
+        if len == self.buf.capacity() {
+            self.reserve(1);
+        }
+
+        unsafe {
+            // infallible
+            // The spot to put the new value
+            {
+                let p = self.as_mut_ptr().add(index);
+                // Shift everything over to make space. (Duplicating the
+                // `index`th element into two consecutive places.)
+                ptr::copy(p, p.offset(1), len - index);
+                // Write it in, overwriting the first copy of the `index`th
+                // element.
+                ptr::write(p, element);
+            }
+            self.set_len(len + 1);
+        }
+    }
+
+    /// Removes and returns the element at position `index` within the vector,
+    /// shifting all elements after it to the left.
+    ///
+    /// Note: Because this shifts over the remaining elements, it has a
+    /// worst-case performance of *O*(*n*). If you don't need the order of elements
+    /// to be preserved, use [`swap_remove`] instead. If you'd like to remove
+    /// elements from the beginning of the `Vec`, consider using
+    /// [`VecDeque::pop_front`] instead.
+    ///
+    /// [`swap_remove`]: Vec::swap_remove
+    /// [`VecDeque::pop_front`]: crate::collections::VecDeque::pop_front
+    ///
+    /// # Panics
+    ///
+    /// Panics if `index` is out of bounds.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = vec![1, 2, 3];
+    /// assert_eq!(v.remove(1), 2);
+    /// assert_eq!(v, [1, 3]);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[track_caller]
+    pub fn remove(&mut self, index: usize) -> T {
+        #[cold]
+        #[inline(never)]
+        #[track_caller]
+        fn assert_failed(index: usize, len: usize) -> ! {
+            panic!("removal index (is {index}) should be < len (is {len})");
+        }
+
+        let len = self.len();
+        if index >= len {
+            assert_failed(index, len);
+        }
+        unsafe {
+            // infallible
+            let ret;
+            {
+                // the place we are taking from.
+                let ptr = self.as_mut_ptr().add(index);
+                // copy it out, unsafely having a copy of the value on
+                // the stack and in the vector at the same time.
+                ret = ptr::read(ptr);
+
+                // Shift everything down to fill in that spot.
+                ptr::copy(ptr.offset(1), ptr, len - index - 1);
+            }
+            self.set_len(len - 1);
+            ret
+        }
+    }
+
+    /// Retains only the elements specified by the predicate.
+    ///
+    /// In other words, remove all elements `e` for which `f(&e)` returns `false`.
+    /// This method operates in place, visiting each element exactly once in the
+    /// original order, and preserves the order of the retained elements.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3, 4];
+    /// vec.retain(|&x| x % 2 == 0);
+    /// assert_eq!(vec, [2, 4]);
+    /// ```
+    ///
+    /// Because the elements are visited exactly once in the original order,
+    /// external state may be used to decide which elements to keep.
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3, 4, 5];
+    /// let keep = [false, true, true, false, true];
+    /// let mut iter = keep.iter();
+    /// vec.retain(|_| *iter.next().unwrap());
+    /// assert_eq!(vec, [2, 3, 5]);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn retain<F>(&mut self, mut f: F)
+    where
+        F: FnMut(&T) -> bool,
+    {
+        self.retain_mut(|elem| f(elem));
+    }
+
+    /// Retains only the elements specified by the predicate, passing a mutable reference to it.
+    ///
+    /// In other words, remove all elements `e` such that `f(&mut e)` returns `false`.
+    /// This method operates in place, visiting each element exactly once in the
+    /// original order, and preserves the order of the retained elements.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3, 4];
+    /// vec.retain_mut(|x| if *x > 3 {
+    ///     false
+    /// } else {
+    ///     *x += 1;
+    ///     true
+    /// });
+    /// assert_eq!(vec, [2, 3, 4]);
+    /// ```
+    #[stable(feature = "vec_retain_mut", since = "1.61.0")]
+    pub fn retain_mut<F>(&mut self, mut f: F)
+    where
+        F: FnMut(&mut T) -> bool,
+    {
+        let original_len = self.len();
+        // Avoid double drop if the drop guard is not executed,
+        // since we may make some holes during the process.
+        unsafe { self.set_len(0) };
+
+        // Vec: [Kept, Kept, Hole, Hole, Hole, Hole, Unchecked, Unchecked]
+        //      |<-              processed len   ->| ^- next to check
+        //                  |<-  deleted cnt     ->|
+        //      |<-              original_len                          ->|
+        // Kept: Elements which predicate returns true on.
+        // Hole: Moved or dropped element slot.
+        // Unchecked: Unchecked valid elements.
+        //
+        // This drop guard will be invoked when predicate or `drop` of element panicked.
+        // It shifts unchecked elements to cover holes and `set_len` to the correct length.
+        // In cases when predicate and `drop` never panick, it will be optimized out.
+        struct BackshiftOnDrop<'a, T, A: Allocator> {
+            v: &'a mut Vec<T, A>,
+            processed_len: usize,
+            deleted_cnt: usize,
+            original_len: usize,
+        }
+
+        impl<T, A: Allocator> Drop for BackshiftOnDrop<'_, T, A> {
+            fn drop(&mut self) {
+                if self.deleted_cnt > 0 {
+                    // SAFETY: Trailing unchecked items must be valid since we never touch them.
+                    unsafe {
+                        ptr::copy(
+                            self.v.as_ptr().add(self.processed_len),
+                            self.v.as_mut_ptr().add(self.processed_len - self.deleted_cnt),
+                            self.original_len - self.processed_len,
+                        );
+                    }
+                }
+                // SAFETY: After filling holes, all items are in contiguous memory.
+                unsafe {
+                    self.v.set_len(self.original_len - self.deleted_cnt);
+                }
+            }
+        }
+
+        let mut g = BackshiftOnDrop { v: self, processed_len: 0, deleted_cnt: 0, original_len };
+
+        fn process_loop<F, T, A: Allocator, const DELETED: bool>(
+            original_len: usize,
+            f: &mut F,
+            g: &mut BackshiftOnDrop<'_, T, A>,
+        ) where
+            F: FnMut(&mut T) -> bool,
+        {
+            while g.processed_len != original_len {
+                // SAFETY: Unchecked element must be valid.
+                let cur = unsafe { &mut *g.v.as_mut_ptr().add(g.processed_len) };
+                if !f(cur) {
+                    // Advance early to avoid double drop if `drop_in_place` panicked.
+                    g.processed_len += 1;
+                    g.deleted_cnt += 1;
+                    // SAFETY: We never touch this element again after dropped.
+                    unsafe { ptr::drop_in_place(cur) };
+                    // We already advanced the counter.
+                    if DELETED {
+                        continue;
+                    } else {
+                        break;
+                    }
+                }
+                if DELETED {
+                    // SAFETY: `deleted_cnt` > 0, so the hole slot must not overlap with current element.
+                    // We use copy for move, and never touch this element again.
+                    unsafe {
+                        let hole_slot = g.v.as_mut_ptr().add(g.processed_len - g.deleted_cnt);
+                        ptr::copy_nonoverlapping(cur, hole_slot, 1);
+                    }
+                }
+                g.processed_len += 1;
+            }
+        }
+
+        // Stage 1: Nothing was deleted.
+        process_loop::<F, T, A, false>(original_len, &mut f, &mut g);
+
+        // Stage 2: Some elements were deleted.
+        process_loop::<F, T, A, true>(original_len, &mut f, &mut g);
+
+        // All item are processed. This can be optimized to `set_len` by LLVM.
+        drop(g);
+    }
+
+    /// Removes all but the first of consecutive elements in the vector that resolve to the same
+    /// key.
+    ///
+    /// If the vector is sorted, this removes all duplicates.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![10, 20, 21, 30, 20];
+    ///
+    /// vec.dedup_by_key(|i| *i / 10);
+    ///
+    /// assert_eq!(vec, [10, 20, 30, 20]);
+    /// ```
+    #[stable(feature = "dedup_by", since = "1.16.0")]
+    #[inline]
+    pub fn dedup_by_key<F, K>(&mut self, mut key: F)
+    where
+        F: FnMut(&mut T) -> K,
+        K: PartialEq,
+    {
+        self.dedup_by(|a, b| key(a) == key(b))
+    }
+
+    /// Removes all but the first of consecutive elements in the vector satisfying a given equality
+    /// relation.
+    ///
+    /// The `same_bucket` function is passed references to two elements from the vector and
+    /// must determine if the elements compare equal. The elements are passed in opposite order
+    /// from their order in the slice, so if `same_bucket(a, b)` returns `true`, `a` is removed.
+    ///
+    /// If the vector is sorted, this removes all duplicates.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec!["foo", "bar", "Bar", "baz", "bar"];
+    ///
+    /// vec.dedup_by(|a, b| a.eq_ignore_ascii_case(b));
+    ///
+    /// assert_eq!(vec, ["foo", "bar", "baz", "bar"]);
+    /// ```
+    #[stable(feature = "dedup_by", since = "1.16.0")]
+    pub fn dedup_by<F>(&mut self, mut same_bucket: F)
+    where
+        F: FnMut(&mut T, &mut T) -> bool,
+    {
+        let len = self.len();
+        if len <= 1 {
+            return;
+        }
+
+        /* INVARIANT: vec.len() > read >= write > write-1 >= 0 */
+        struct FillGapOnDrop<'a, T, A: core::alloc::Allocator> {
+            /* Offset of the element we want to check if it is duplicate */
+            read: usize,
+
+            /* Offset of the place where we want to place the non-duplicate
+             * when we find it. */
+            write: usize,
+
+            /* The Vec that would need correction if `same_bucket` panicked */
+            vec: &'a mut Vec<T, A>,
+        }
+
+        impl<'a, T, A: core::alloc::Allocator> Drop for FillGapOnDrop<'a, T, A> {
+            fn drop(&mut self) {
+                /* This code gets executed when `same_bucket` panics */
+
+                /* SAFETY: invariant guarantees that `read - write`
+                 * and `len - read` never overflow and that the copy is always
+                 * in-bounds. */
+                unsafe {
+                    let ptr = self.vec.as_mut_ptr();
+                    let len = self.vec.len();
+
+                    /* How many items were left when `same_bucket` panicked.
+                     * Basically vec[read..].len() */
+                    let items_left = len.wrapping_sub(self.read);
+
+                    /* Pointer to first item in vec[write..write+items_left] slice */
+                    let dropped_ptr = ptr.add(self.write);
+                    /* Pointer to first item in vec[read..] slice */
+                    let valid_ptr = ptr.add(self.read);
+
+                    /* Copy `vec[read..]` to `vec[write..write+items_left]`.
+                     * The slices can overlap, so `copy_nonoverlapping` cannot be used */
+                    ptr::copy(valid_ptr, dropped_ptr, items_left);
+
+                    /* How many items have been already dropped
+                     * Basically vec[read..write].len() */
+                    let dropped = self.read.wrapping_sub(self.write);
+
+                    self.vec.set_len(len - dropped);
+                }
+            }
+        }
+
+        let mut gap = FillGapOnDrop { read: 1, write: 1, vec: self };
+        let ptr = gap.vec.as_mut_ptr();
+
+        /* Drop items while going through Vec, it should be more efficient than
+         * doing slice partition_dedup + truncate */
+
+        /* SAFETY: Because of the invariant, read_ptr, prev_ptr and write_ptr
+         * are always in-bounds and read_ptr never aliases prev_ptr */
+        unsafe {
+            while gap.read < len {
+                let read_ptr = ptr.add(gap.read);
+                let prev_ptr = ptr.add(gap.write.wrapping_sub(1));
+
+                if same_bucket(&mut *read_ptr, &mut *prev_ptr) {
+                    // Increase `gap.read` now since the drop may panic.
+                    gap.read += 1;
+                    /* We have found duplicate, drop it in-place */
+                    ptr::drop_in_place(read_ptr);
+                } else {
+                    let write_ptr = ptr.add(gap.write);
+
+                    /* Because `read_ptr` can be equal to `write_ptr`, we either
+                     * have to use `copy` or conditional `copy_nonoverlapping`.
+                     * Looks like the first option is faster. */
+                    ptr::copy(read_ptr, write_ptr, 1);
+
+                    /* We have filled that place, so go further */
+                    gap.write += 1;
+                    gap.read += 1;
+                }
+            }
+
+            /* Technically we could let `gap` clean up with its Drop, but
+             * when `same_bucket` is guaranteed to not panic, this bloats a little
+             * the codegen, so we just do it manually */
+            gap.vec.set_len(gap.write);
+            mem::forget(gap);
+        }
+    }
+
+    /// Appends an element to the back of a collection.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity exceeds `isize::MAX` bytes.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2];
+    /// vec.push(3);
+    /// assert_eq!(vec, [1, 2, 3]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn push(&mut self, value: T) {
+        // This will panic or abort if we would allocate > isize::MAX bytes
+        // or if the length increment would overflow for zero-sized types.
+        if self.len == self.buf.capacity() {
+            self.buf.reserve_for_push(self.len);
+        }
+        unsafe {
+            let end = self.as_mut_ptr().add(self.len);
+            ptr::write(end, value);
+            self.len += 1;
+        }
+    }
+
+    /// Tries to append an element to the back of a collection.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2];
+    /// vec.try_push(3).unwrap();
+    /// assert_eq!(vec, [1, 2, 3]);
+    /// ```
+    #[inline]
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_push(&mut self, value: T) -> Result<(), TryReserveError> {
+        if self.len == self.buf.capacity() {
+            self.buf.try_reserve_for_push(self.len)?;
+        }
+        unsafe {
+            let end = self.as_mut_ptr().add(self.len);
+            ptr::write(end, value);
+            self.len += 1;
+        }
+        Ok(())
+    }
+
+    /// Removes the last element from a vector and returns it, or [`None`] if it
+    /// is empty.
+    ///
+    /// If you'd like to pop the first element, consider using
+    /// [`VecDeque::pop_front`] instead.
+    ///
+    /// [`VecDeque::pop_front`]: crate::collections::VecDeque::pop_front
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3];
+    /// assert_eq!(vec.pop(), Some(3));
+    /// assert_eq!(vec, [1, 2]);
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn pop(&mut self) -> Option<T> {
+        if self.len == 0 {
+            None
+        } else {
+            unsafe {
+                self.len -= 1;
+                Some(ptr::read(self.as_ptr().add(self.len())))
+            }
+        }
+    }
+
+    /// Moves all the elements of `other` into `self`, leaving `other` empty.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the number of elements in the vector overflows a `usize`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3];
+    /// let mut vec2 = vec![4, 5, 6];
+    /// vec.append(&mut vec2);
+    /// assert_eq!(vec, [1, 2, 3, 4, 5, 6]);
+    /// assert_eq!(vec2, []);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "append", since = "1.4.0")]
+    pub fn append(&mut self, other: &mut Self) {
+        unsafe {
+            self.append_elements(other.as_slice() as _);
+            other.set_len(0);
+        }
+    }
+
+    /// Appends elements to `self` from other buffer.
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    unsafe fn append_elements(&mut self, other: *const [T]) {
+        let count = unsafe { (*other).len() };
+        self.reserve(count);
+        let len = self.len();
+        unsafe { ptr::copy_nonoverlapping(other as *const T, self.as_mut_ptr().add(len), count) };
+        self.len += count;
+    }
+
+    /// Tries to append elements to `self` from other buffer.
+    #[inline]
+    unsafe fn try_append_elements(&mut self, other: *const [T]) -> Result<(), TryReserveError> {
+        let count = unsafe { (*other).len() };
+        self.try_reserve(count)?;
+        let len = self.len();
+        unsafe { ptr::copy_nonoverlapping(other as *const T, self.as_mut_ptr().add(len), count) };
+        self.len += count;
+        Ok(())
+    }
+
+    /// Removes the specified range from the vector in bulk, returning all
+    /// removed elements as an iterator. If the iterator is dropped before
+    /// being fully consumed, it drops the remaining removed elements.
+    ///
+    /// The returned iterator keeps a mutable borrow on the vector to optimize
+    /// its implementation.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the starting point is greater than the end point or if
+    /// the end point is greater than the length of the vector.
+    ///
+    /// # Leaking
+    ///
+    /// If the returned iterator goes out of scope without being dropped (due to
+    /// [`mem::forget`], for example), the vector may have lost and leaked
+    /// elements arbitrarily, including elements outside the range.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = vec![1, 2, 3];
+    /// let u: Vec<_> = v.drain(1..).collect();
+    /// assert_eq!(v, &[1]);
+    /// assert_eq!(u, &[2, 3]);
+    ///
+    /// // A full range clears the vector, like `clear()` does
+    /// v.drain(..);
+    /// assert_eq!(v, &[]);
+    /// ```
+    #[stable(feature = "drain", since = "1.6.0")]
+    pub fn drain<R>(&mut self, range: R) -> Drain<'_, T, A>
+    where
+        R: RangeBounds<usize>,
+    {
+        // Memory safety
+        //
+        // When the Drain is first created, it shortens the length of
+        // the source vector to make sure no uninitialized or moved-from elements
+        // are accessible at all if the Drain's destructor never gets to run.
+        //
+        // Drain will ptr::read out the values to remove.
+        // When finished, remaining tail of the vec is copied back to cover
+        // the hole, and the vector length is restored to the new length.
+        //
+        let len = self.len();
+        let Range { start, end } = slice::range(range, ..len);
+
+        unsafe {
+            // set self.vec length's to start, to be safe in case Drain is leaked
+            self.set_len(start);
+            // Use the borrow in the IterMut to indicate borrowing behavior of the
+            // whole Drain iterator (like &mut T).
+            let range_slice = slice::from_raw_parts_mut(self.as_mut_ptr().add(start), end - start);
+            Drain {
+                tail_start: end,
+                tail_len: len - end,
+                iter: range_slice.iter(),
+                vec: NonNull::from(self),
+            }
+        }
+    }
+
+    /// Clears the vector, removing all values.
+    ///
+    /// Note that this method has no effect on the allocated capacity
+    /// of the vector.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = vec![1, 2, 3];
+    ///
+    /// v.clear();
+    ///
+    /// assert!(v.is_empty());
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn clear(&mut self) {
+        let elems: *mut [T] = self.as_mut_slice();
+
+        // SAFETY:
+        // - `elems` comes directly from `as_mut_slice` and is therefore valid.
+        // - Setting `self.len` before calling `drop_in_place` means that,
+        //   if an element's `Drop` impl panics, the vector's `Drop` impl will
+        //   do nothing (leaking the rest of the elements) instead of dropping
+        //   some twice.
+        unsafe {
+            self.len = 0;
+            ptr::drop_in_place(elems);
+        }
+    }
+
+    /// Returns the number of elements in the vector, also referred to
+    /// as its 'length'.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let a = vec![1, 2, 3];
+    /// assert_eq!(a.len(), 3);
+    /// ```
+    #[inline]
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn len(&self) -> usize {
+        self.len
+    }
+
+    /// Returns `true` if the vector contains no elements.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = Vec::new();
+    /// assert!(v.is_empty());
+    ///
+    /// v.push(1);
+    /// assert!(!v.is_empty());
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    pub fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    /// Splits the collection into two at the given index.
+    ///
+    /// Returns a newly allocated vector containing the elements in the range
+    /// `[at, len)`. After the call, the original vector will be left containing
+    /// the elements `[0, at)` with its previous capacity unchanged.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `at > len`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3];
+    /// let vec2 = vec.split_off(1);
+    /// assert_eq!(vec, [1]);
+    /// assert_eq!(vec2, [2, 3]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[must_use = "use `.truncate()` if you don't need the other half"]
+    #[stable(feature = "split_off", since = "1.4.0")]
+    pub fn split_off(&mut self, at: usize) -> Self
+    where
+        A: Clone,
+    {
+        #[cold]
+        #[inline(never)]
+        fn assert_failed(at: usize, len: usize) -> ! {
+            panic!("`at` split index (is {at}) should be <= len (is {len})");
+        }
+
+        if at > self.len() {
+            assert_failed(at, self.len());
+        }
+
+        if at == 0 {
+            // the new vector can take over the original buffer and avoid the copy
+            return mem::replace(
+                self,
+                Vec::with_capacity_in(self.capacity(), self.allocator().clone()),
+            );
+        }
+
+        let other_len = self.len - at;
+        let mut other = Vec::with_capacity_in(other_len, self.allocator().clone());
+
+        // Unsafely `set_len` and copy items to `other`.
+        unsafe {
+            self.set_len(at);
+            other.set_len(other_len);
+
+            ptr::copy_nonoverlapping(self.as_ptr().add(at), other.as_mut_ptr(), other.len());
+        }
+        other
+    }
+
+    /// Resizes the `Vec` in-place so that `len` is equal to `new_len`.
+    ///
+    /// If `new_len` is greater than `len`, the `Vec` is extended by the
+    /// difference, with each additional slot filled with the result of
+    /// calling the closure `f`. The return values from `f` will end up
+    /// in the `Vec` in the order they have been generated.
+    ///
+    /// If `new_len` is less than `len`, the `Vec` is simply truncated.
+    ///
+    /// This method uses a closure to create new values on every push. If
+    /// you'd rather [`Clone`] a given value, use [`Vec::resize`]. If you
+    /// want to use the [`Default`] trait to generate values, you can
+    /// pass [`Default::default`] as the second argument.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 3];
+    /// vec.resize_with(5, Default::default);
+    /// assert_eq!(vec, [1, 2, 3, 0, 0]);
+    ///
+    /// let mut vec = vec![];
+    /// let mut p = 1;
+    /// vec.resize_with(4, || { p *= 2; p });
+    /// assert_eq!(vec, [2, 4, 8, 16]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "vec_resize_with", since = "1.33.0")]
+    pub fn resize_with<F>(&mut self, new_len: usize, f: F)
+    where
+        F: FnMut() -> T,
+    {
+        let len = self.len();
+        if new_len > len {
+            self.extend_with(new_len - len, ExtendFunc(f));
+        } else {
+            self.truncate(new_len);
+        }
+    }
+
+    /// Consumes and leaks the `Vec`, returning a mutable reference to the contents,
+    /// `&'a mut [T]`. Note that the type `T` must outlive the chosen lifetime
+    /// `'a`. If the type has only static references, or none at all, then this
+    /// may be chosen to be `'static`.
+    ///
+    /// As of Rust 1.57, this method does not reallocate or shrink the `Vec`,
+    /// so the leaked allocation may include unused capacity that is not part
+    /// of the returned slice.
+    ///
+    /// This function is mainly useful for data that lives for the remainder of
+    /// the program's life. Dropping the returned reference will cause a memory
+    /// leak.
+    ///
+    /// # Examples
+    ///
+    /// Simple usage:
+    ///
+    /// ```
+    /// let x = vec![1, 2, 3];
+    /// let static_ref: &'static mut [usize] = x.leak();
+    /// static_ref[0] += 1;
+    /// assert_eq!(static_ref, &[2, 2, 3]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "vec_leak", since = "1.47.0")]
+    #[inline]
+    pub fn leak<'a>(self) -> &'a mut [T]
+    where
+        A: 'a,
+    {
+        let mut me = ManuallyDrop::new(self);
+        unsafe { slice::from_raw_parts_mut(me.as_mut_ptr(), me.len) }
+    }
+
+    /// Returns the remaining spare capacity of the vector as a slice of
+    /// `MaybeUninit<T>`.
+    ///
+    /// The returned slice can be used to fill the vector with data (e.g. by
+    /// reading from a file) before marking the data as initialized using the
+    /// [`set_len`] method.
+    ///
+    /// [`set_len`]: Vec::set_len
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// // Allocate vector big enough for 10 elements.
+    /// let mut v = Vec::with_capacity(10);
+    ///
+    /// // Fill in the first 3 elements.
+    /// let uninit = v.spare_capacity_mut();
+    /// uninit[0].write(0);
+    /// uninit[1].write(1);
+    /// uninit[2].write(2);
+    ///
+    /// // Mark the first 3 elements of the vector as being initialized.
+    /// unsafe {
+    ///     v.set_len(3);
+    /// }
+    ///
+    /// assert_eq!(&v, &[0, 1, 2]);
+    /// ```
+    #[stable(feature = "vec_spare_capacity", since = "1.60.0")]
+    #[inline]
+    pub fn spare_capacity_mut(&mut self) -> &mut [MaybeUninit<T>] {
+        // Note:
+        // This method is not implemented in terms of `split_at_spare_mut`,
+        // to prevent invalidation of pointers to the buffer.
+        unsafe {
+            slice::from_raw_parts_mut(
+                self.as_mut_ptr().add(self.len) as *mut MaybeUninit<T>,
+                self.buf.capacity() - self.len,
+            )
+        }
+    }
+
+    /// Returns vector content as a slice of `T`, along with the remaining spare
+    /// capacity of the vector as a slice of `MaybeUninit<T>`.
+    ///
+    /// The returned spare capacity slice can be used to fill the vector with data
+    /// (e.g. by reading from a file) before marking the data as initialized using
+    /// the [`set_len`] method.
+    ///
+    /// [`set_len`]: Vec::set_len
+    ///
+    /// Note that this is a low-level API, which should be used with care for
+    /// optimization purposes. If you need to append data to a `Vec`
+    /// you can use [`push`], [`extend`], [`extend_from_slice`],
+    /// [`extend_from_within`], [`insert`], [`append`], [`resize`] or
+    /// [`resize_with`], depending on your exact needs.
+    ///
+    /// [`push`]: Vec::push
+    /// [`extend`]: Vec::extend
+    /// [`extend_from_slice`]: Vec::extend_from_slice
+    /// [`extend_from_within`]: Vec::extend_from_within
+    /// [`insert`]: Vec::insert
+    /// [`append`]: Vec::append
+    /// [`resize`]: Vec::resize
+    /// [`resize_with`]: Vec::resize_with
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(vec_split_at_spare)]
+    ///
+    /// let mut v = vec![1, 1, 2];
+    ///
+    /// // Reserve additional space big enough for 10 elements.
+    /// v.reserve(10);
+    ///
+    /// let (init, uninit) = v.split_at_spare_mut();
+    /// let sum = init.iter().copied().sum::<u32>();
+    ///
+    /// // Fill in the next 4 elements.
+    /// uninit[0].write(sum);
+    /// uninit[1].write(sum * 2);
+    /// uninit[2].write(sum * 3);
+    /// uninit[3].write(sum * 4);
+    ///
+    /// // Mark the 4 elements of the vector as being initialized.
+    /// unsafe {
+    ///     let len = v.len();
+    ///     v.set_len(len + 4);
+    /// }
+    ///
+    /// assert_eq!(&v, &[1, 1, 2, 4, 8, 12, 16]);
+    /// ```
+    #[unstable(feature = "vec_split_at_spare", issue = "81944")]
+    #[inline]
+    pub fn split_at_spare_mut(&mut self) -> (&mut [T], &mut [MaybeUninit<T>]) {
+        // SAFETY:
+        // - len is ignored and so never changed
+        let (init, spare, _) = unsafe { self.split_at_spare_mut_with_len() };
+        (init, spare)
+    }
+
+    /// Safety: changing returned .2 (&mut usize) is considered the same as calling `.set_len(_)`.
+    ///
+    /// This method provides unique access to all vec parts at once in `extend_from_within`.
+    unsafe fn split_at_spare_mut_with_len(
+        &mut self,
+    ) -> (&mut [T], &mut [MaybeUninit<T>], &mut usize) {
+        let ptr = self.as_mut_ptr();
+        // SAFETY:
+        // - `ptr` is guaranteed to be valid for `self.len` elements
+        // - but the allocation extends out to `self.buf.capacity()` elements, possibly
+        // uninitialized
+        let spare_ptr = unsafe { ptr.add(self.len) };
+        let spare_ptr = spare_ptr.cast::<MaybeUninit<T>>();
+        let spare_len = self.buf.capacity() - self.len;
+
+        // SAFETY:
+        // - `ptr` is guaranteed to be valid for `self.len` elements
+        // - `spare_ptr` is pointing one element past the buffer, so it doesn't overlap with `initialized`
+        unsafe {
+            let initialized = slice::from_raw_parts_mut(ptr, self.len);
+            let spare = slice::from_raw_parts_mut(spare_ptr, spare_len);
+
+            (initialized, spare, &mut self.len)
+        }
+    }
+}
+
+impl<T: Clone, A: Allocator> Vec<T, A> {
+    /// Resizes the `Vec` in-place so that `len` is equal to `new_len`.
+    ///
+    /// If `new_len` is greater than `len`, the `Vec` is extended by the
+    /// difference, with each additional slot filled with `value`.
+    /// If `new_len` is less than `len`, the `Vec` is simply truncated.
+    ///
+    /// This method requires `T` to implement [`Clone`],
+    /// in order to be able to clone the passed value.
+    /// If you need more flexibility (or want to rely on [`Default`] instead of
+    /// [`Clone`]), use [`Vec::resize_with`].
+    /// If you only need to resize to a smaller size, use [`Vec::truncate`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec!["hello"];
+    /// vec.resize(3, "world");
+    /// assert_eq!(vec, ["hello", "world", "world"]);
+    ///
+    /// let mut vec = vec![1, 2, 3, 4];
+    /// vec.resize(2, 0);
+    /// assert_eq!(vec, [1, 2]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "vec_resize", since = "1.5.0")]
+    pub fn resize(&mut self, new_len: usize, value: T) {
+        let len = self.len();
+
+        if new_len > len {
+            self.extend_with(new_len - len, ExtendElement(value))
+        } else {
+            self.truncate(new_len);
+        }
+    }
+
+    /// Tries to resize the `Vec` in-place so that `len` is equal to `new_len`.
+    ///
+    /// If `new_len` is greater than `len`, the `Vec` is extended by the
+    /// difference, with each additional slot filled with `value`.
+    /// If `new_len` is less than `len`, the `Vec` is simply truncated.
+    ///
+    /// This method requires `T` to implement [`Clone`],
+    /// in order to be able to clone the passed value.
+    /// If you need more flexibility (or want to rely on [`Default`] instead of
+    /// [`Clone`]), use [`Vec::resize_with`].
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec!["hello"];
+    /// vec.try_resize(3, "world").unwrap();
+    /// assert_eq!(vec, ["hello", "world", "world"]);
+    ///
+    /// let mut vec = vec![1, 2, 3, 4];
+    /// vec.try_resize(2, 0).unwrap();
+    /// assert_eq!(vec, [1, 2]);
+    ///
+    /// let mut vec = vec![42];
+    /// let result = vec.try_resize(usize::MAX, 0);
+    /// assert!(result.is_err());
+    /// ```
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_resize(&mut self, new_len: usize, value: T) -> Result<(), TryReserveError> {
+        let len = self.len();
+
+        if new_len > len {
+            self.try_extend_with(new_len - len, ExtendElement(value))
+        } else {
+            self.truncate(new_len);
+            Ok(())
+        }
+    }
+
+    /// Clones and appends all elements in a slice to the `Vec`.
+    ///
+    /// Iterates over the slice `other`, clones each element, and then appends
+    /// it to this `Vec`. The `other` slice is traversed in-order.
+    ///
+    /// Note that this function is same as [`extend`] except that it is
+    /// specialized to work with slices instead. If and when Rust gets
+    /// specialization this function will likely be deprecated (but still
+    /// available).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1];
+    /// vec.extend_from_slice(&[2, 3, 4]);
+    /// assert_eq!(vec, [1, 2, 3, 4]);
+    /// ```
+    ///
+    /// [`extend`]: Vec::extend
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "vec_extend_from_slice", since = "1.6.0")]
+    pub fn extend_from_slice(&mut self, other: &[T]) {
+        self.spec_extend(other.iter())
+    }
+
+    /// Tries to clone and append all elements in a slice to the `Vec`.
+    ///
+    /// Iterates over the slice `other`, clones each element, and then appends
+    /// it to this `Vec`. The `other` slice is traversed in-order.
+    ///
+    /// Note that this function is same as [`extend`] except that it is
+    /// specialized to work with slices instead. If and when Rust gets
+    /// specialization this function will likely be deprecated (but still
+    /// available).
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1];
+    /// vec.try_extend_from_slice(&[2, 3, 4]).unwrap();
+    /// assert_eq!(vec, [1, 2, 3, 4]);
+    /// ```
+    ///
+    /// [`extend`]: Vec::extend
+    #[stable(feature = "kernel", since = "1.0.0")]
+    pub fn try_extend_from_slice(&mut self, other: &[T]) -> Result<(), TryReserveError> {
+        self.try_spec_extend(other.iter())
+    }
+
+    /// Copies elements from `src` range to the end of the vector.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the starting point is greater than the end point or if
+    /// the end point is greater than the length of the vector.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![0, 1, 2, 3, 4];
+    ///
+    /// vec.extend_from_within(2..);
+    /// assert_eq!(vec, [0, 1, 2, 3, 4, 2, 3, 4]);
+    ///
+    /// vec.extend_from_within(..2);
+    /// assert_eq!(vec, [0, 1, 2, 3, 4, 2, 3, 4, 0, 1]);
+    ///
+    /// vec.extend_from_within(4..8);
+    /// assert_eq!(vec, [0, 1, 2, 3, 4, 2, 3, 4, 0, 1, 4, 2, 3, 4]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[stable(feature = "vec_extend_from_within", since = "1.53.0")]
+    pub fn extend_from_within<R>(&mut self, src: R)
+    where
+        R: RangeBounds<usize>,
+    {
+        let range = slice::range(src, ..self.len());
+        self.reserve(range.len());
+
+        // SAFETY:
+        // - `slice::range` guarantees  that the given range is valid for indexing self
+        unsafe {
+            self.spec_extend_from_within(range);
+        }
+    }
+}
+
+impl<T, A: Allocator, const N: usize> Vec<[T; N], A> {
+    /// Takes a `Vec<[T; N]>` and flattens it into a `Vec<T>`.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the length of the resulting vector would overflow a `usize`.
+    ///
+    /// This is only possible when flattening a vector of arrays of zero-sized
+    /// types, and thus tends to be irrelevant in practice. If
+    /// `size_of::<T>() > 0`, this will never panic.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(slice_flatten)]
+    ///
+    /// let mut vec = vec![[1, 2, 3], [4, 5, 6], [7, 8, 9]];
+    /// assert_eq!(vec.pop(), Some([7, 8, 9]));
+    ///
+    /// let mut flattened = vec.into_flattened();
+    /// assert_eq!(flattened.pop(), Some(6));
+    /// ```
+    #[unstable(feature = "slice_flatten", issue = "95629")]
+    pub fn into_flattened(self) -> Vec<T, A> {
+        let (ptr, len, cap, alloc) = self.into_raw_parts_with_alloc();
+        let (new_len, new_cap) = if mem::size_of::<T>() == 0 {
+            (len.checked_mul(N).expect("vec len overflow"), usize::MAX)
+        } else {
+            // SAFETY:
+            // - `cap * N` cannot overflow because the allocation is already in
+            // the address space.
+            // - Each `[T; N]` has `N` valid elements, so there are `len * N`
+            // valid elements in the allocation.
+            unsafe { (len.unchecked_mul(N), cap.unchecked_mul(N)) }
+        };
+        // SAFETY:
+        // - `ptr` was allocated by `self`
+        // - `ptr` is well-aligned because `[T; N]` has the same alignment as `T`.
+        // - `new_cap` refers to the same sized allocation as `cap` because
+        // `new_cap * size_of::<T>()` == `cap * size_of::<[T; N]>()`
+        // - `len` <= `cap`, so `len * N` <= `cap * N`.
+        unsafe { Vec::<T, A>::from_raw_parts_in(ptr.cast(), new_len, new_cap, alloc) }
+    }
+}
+
+// This code generalizes `extend_with_{element,default}`.
+trait ExtendWith<T> {
+    fn next(&mut self) -> T;
+    fn last(self) -> T;
+}
+
+struct ExtendElement<T>(T);
+impl<T: Clone> ExtendWith<T> for ExtendElement<T> {
+    fn next(&mut self) -> T {
+        self.0.clone()
+    }
+    fn last(self) -> T {
+        self.0
+    }
+}
+
+struct ExtendFunc<F>(F);
+impl<T, F: FnMut() -> T> ExtendWith<T> for ExtendFunc<F> {
+    fn next(&mut self) -> T {
+        (self.0)()
+    }
+    fn last(mut self) -> T {
+        (self.0)()
+    }
+}
+
+impl<T, A: Allocator> Vec<T, A> {
+    #[cfg(not(no_global_oom_handling))]
+    /// Extend the vector by `n` values, using the given generator.
+    fn extend_with<E: ExtendWith<T>>(&mut self, n: usize, mut value: E) {
+        self.reserve(n);
+
+        unsafe {
+            let mut ptr = self.as_mut_ptr().add(self.len());
+            // Use SetLenOnDrop to work around bug where compiler
+            // might not realize the store through `ptr` through self.set_len()
+            // don't alias.
+            let mut local_len = SetLenOnDrop::new(&mut self.len);
+
+            // Write all elements except the last one
+            for _ in 1..n {
+                ptr::write(ptr, value.next());
+                ptr = ptr.offset(1);
+                // Increment the length in every step in case next() panics
+                local_len.increment_len(1);
+            }
+
+            if n > 0 {
+                // We can write the last element directly without cloning needlessly
+                ptr::write(ptr, value.last());
+                local_len.increment_len(1);
+            }
+
+            // len set by scope guard
+        }
+    }
+
+    /// Try to extend the vector by `n` values, using the given generator.
+    fn try_extend_with<E: ExtendWith<T>>(&mut self, n: usize, mut value: E) -> Result<(), TryReserveError> {
+        self.try_reserve(n)?;
+
+        unsafe {
+            let mut ptr = self.as_mut_ptr().add(self.len());
+            // Use SetLenOnDrop to work around bug where compiler
+            // might not realize the store through `ptr` through self.set_len()
+            // don't alias.
+            let mut local_len = SetLenOnDrop::new(&mut self.len);
+
+            // Write all elements except the last one
+            for _ in 1..n {
+                ptr::write(ptr, value.next());
+                ptr = ptr.offset(1);
+                // Increment the length in every step in case next() panics
+                local_len.increment_len(1);
+            }
+
+            if n > 0 {
+                // We can write the last element directly without cloning needlessly
+                ptr::write(ptr, value.last());
+                local_len.increment_len(1);
+            }
+
+            // len set by scope guard
+            Ok(())
+        }
+    }
+}
+
+impl<T: PartialEq, A: Allocator> Vec<T, A> {
+    /// Removes consecutive repeated elements in the vector according to the
+    /// [`PartialEq`] trait implementation.
+    ///
+    /// If the vector is sorted, this removes all duplicates.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut vec = vec![1, 2, 2, 3, 2];
+    ///
+    /// vec.dedup();
+    ///
+    /// assert_eq!(vec, [1, 2, 3, 2]);
+    /// ```
+    #[stable(feature = "rust1", since = "1.0.0")]
+    #[inline]
+    pub fn dedup(&mut self) {
+        self.dedup_by(|a, b| a == b)
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Internal methods and functions
+////////////////////////////////////////////////////////////////////////////////
+
+#[doc(hidden)]
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+pub fn from_elem<T: Clone>(elem: T, n: usize) -> Vec<T> {
+    <T as SpecFromElem>::from_elem(elem, n, Global)
+}
+
+#[doc(hidden)]
+#[cfg(not(no_global_oom_handling))]
+#[unstable(feature = "allocator_api", issue = "32838")]
+pub fn from_elem_in<T: Clone, A: Allocator>(elem: T, n: usize, alloc: A) -> Vec<T, A> {
+    <T as SpecFromElem>::from_elem(elem, n, alloc)
+}
+
+trait ExtendFromWithinSpec {
+    /// # Safety
+    ///
+    /// - `src` needs to be valid index
+    /// - `self.capacity() - self.len()` must be `>= src.len()`
+    unsafe fn spec_extend_from_within(&mut self, src: Range<usize>);
+}
+
+impl<T: Clone, A: Allocator> ExtendFromWithinSpec for Vec<T, A> {
+    default unsafe fn spec_extend_from_within(&mut self, src: Range<usize>) {
+        // SAFETY:
+        // - len is increased only after initializing elements
+        let (this, spare, len) = unsafe { self.split_at_spare_mut_with_len() };
+
+        // SAFETY:
+        // - caller guaratees that src is a valid index
+        let to_clone = unsafe { this.get_unchecked(src) };
+
+        iter::zip(to_clone, spare)
+            .map(|(src, dst)| dst.write(src.clone()))
+            // Note:
+            // - Element was just initialized with `MaybeUninit::write`, so it's ok to increase len
+            // - len is increased after each element to prevent leaks (see issue #82533)
+            .for_each(|_| *len += 1);
+    }
+}
+
+impl<T: Copy, A: Allocator> ExtendFromWithinSpec for Vec<T, A> {
+    unsafe fn spec_extend_from_within(&mut self, src: Range<usize>) {
+        let count = src.len();
+        {
+            let (init, spare) = self.split_at_spare_mut();
+
+            // SAFETY:
+            // - caller guaratees that `src` is a valid index
+            let source = unsafe { init.get_unchecked(src) };
+
+            // SAFETY:
+            // - Both pointers are created from unique slice references (`&mut [_]`)
+            //   so they are valid and do not overlap.
+            // - Elements are :Copy so it's OK to to copy them, without doing
+            //   anything with the original values
+            // - `count` is equal to the len of `source`, so source is valid for
+            //   `count` reads
+            // - `.reserve(count)` guarantees that `spare.len() >= count` so spare
+            //   is valid for `count` writes
+            unsafe { ptr::copy_nonoverlapping(source.as_ptr(), spare.as_mut_ptr() as _, count) };
+        }
+
+        // SAFETY:
+        // - The elements were just initialized by `copy_nonoverlapping`
+        self.len += count;
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Common trait implementations for Vec
+////////////////////////////////////////////////////////////////////////////////
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> ops::Deref for Vec<T, A> {
+    type Target = [T];
+
+    fn deref(&self) -> &[T] {
+        unsafe { slice::from_raw_parts(self.as_ptr(), self.len) }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> ops::DerefMut for Vec<T, A> {
+    fn deref_mut(&mut self) -> &mut [T] {
+        unsafe { slice::from_raw_parts_mut(self.as_mut_ptr(), self.len) }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+trait SpecCloneFrom {
+    fn clone_from(this: &mut Self, other: &Self);
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T: Clone, A: Allocator> SpecCloneFrom for Vec<T, A> {
+    default fn clone_from(this: &mut Self, other: &Self) {
+        // drop anything that will not be overwritten
+        this.truncate(other.len());
+
+        // self.len <= other.len due to the truncate above, so the
+        // slices here are always in-bounds.
+        let (init, tail) = other.split_at(this.len());
+
+        // reuse the contained values' allocations/resources.
+        this.clone_from_slice(init);
+        this.extend_from_slice(tail);
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T: Copy, A: Allocator> SpecCloneFrom for Vec<T, A> {
+    fn clone_from(this: &mut Self, other: &Self) {
+        this.clear();
+        this.extend_from_slice(other);
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone, A: Allocator + Clone> Clone for Vec<T, A> {
+    #[cfg(not(test))]
+    fn clone(&self) -> Self {
+        let alloc = self.allocator().clone();
+        <[T]>::to_vec_in(&**self, alloc)
+    }
+
+    // HACK(japaric): with cfg(test) the inherent `[T]::to_vec` method, which is
+    // required for this method definition, is not available. Instead use the
+    // `slice::to_vec`  function which is only available with cfg(test)
+    // NB see the slice::hack module in slice.rs for more information
+    #[cfg(test)]
+    fn clone(&self) -> Self {
+        let alloc = self.allocator().clone();
+        crate::slice::to_vec(&**self, alloc)
+    }
+
+    fn clone_from(&mut self, other: &Self) {
+        SpecCloneFrom::clone_from(self, other)
+    }
+}
+
+/// The hash of a vector is the same as that of the corresponding slice,
+/// as required by the `core::borrow::Borrow` implementation.
+///
+/// ```
+/// #![feature(build_hasher_simple_hash_one)]
+/// use std::hash::BuildHasher;
+///
+/// let b = std::collections::hash_map::RandomState::new();
+/// let v: Vec<u8> = vec![0xa8, 0x3c, 0x09];
+/// let s: &[u8] = &[0xa8, 0x3c, 0x09];
+/// assert_eq!(b.hash_one(v), b.hash_one(s));
+/// ```
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Hash, A: Allocator> Hash for Vec<T, A> {
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        Hash::hash(&**self, state)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented(
+    message = "vector indices are of type `usize` or ranges of `usize`",
+    label = "vector indices are of type `usize` or ranges of `usize`"
+)]
+impl<T, I: SliceIndex<[T]>, A: Allocator> Index<I> for Vec<T, A> {
+    type Output = I::Output;
+
+    #[inline]
+    fn index(&self, index: I) -> &Self::Output {
+        Index::index(&**self, index)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_on_unimplemented(
+    message = "vector indices are of type `usize` or ranges of `usize`",
+    label = "vector indices are of type `usize` or ranges of `usize`"
+)]
+impl<T, I: SliceIndex<[T]>, A: Allocator> IndexMut<I> for Vec<T, A> {
+    #[inline]
+    fn index_mut(&mut self, index: I) -> &mut Self::Output {
+        IndexMut::index_mut(&mut **self, index)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> FromIterator<T> for Vec<T> {
+    #[inline]
+    fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Vec<T> {
+        <Self as SpecFromIter<T, I::IntoIter>>::from_iter(iter.into_iter())
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> IntoIterator for Vec<T, A> {
+    type Item = T;
+    type IntoIter = IntoIter<T, A>;
+
+    /// Creates a consuming iterator, that is, one that moves each value out of
+    /// the vector (from start to end). The vector cannot be used after calling
+    /// this.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let v = vec!["a".to_string(), "b".to_string()];
+    /// for s in v.into_iter() {
+    ///     // s has type String, not &String
+    ///     println!("{s}");
+    /// }
+    /// ```
+    #[inline]
+    fn into_iter(self) -> IntoIter<T, A> {
+        unsafe {
+            let mut me = ManuallyDrop::new(self);
+            let alloc = ManuallyDrop::new(ptr::read(me.allocator()));
+            let begin = me.as_mut_ptr();
+            let end = if mem::size_of::<T>() == 0 {
+                arith_offset(begin as *const i8, me.len() as isize) as *const T
+            } else {
+                begin.add(me.len()) as *const T
+            };
+            let cap = me.buf.capacity();
+            IntoIter {
+                buf: NonNull::new_unchecked(begin),
+                phantom: PhantomData,
+                cap,
+                alloc,
+                ptr: begin,
+                end,
+            }
+        }
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T, A: Allocator> IntoIterator for &'a Vec<T, A> {
+    type Item = &'a T;
+    type IntoIter = slice::Iter<'a, T>;
+
+    fn into_iter(self) -> slice::Iter<'a, T> {
+        self.iter()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<'a, T, A: Allocator> IntoIterator for &'a mut Vec<T, A> {
+    type Item = &'a mut T;
+    type IntoIter = slice::IterMut<'a, T>;
+
+    fn into_iter(self) -> slice::IterMut<'a, T> {
+        self.iter_mut()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> Extend<T> for Vec<T, A> {
+    #[inline]
+    fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
+        <Self as SpecExtend<T, I::IntoIter>>::spec_extend(self, iter.into_iter())
+    }
+
+    #[inline]
+    fn extend_one(&mut self, item: T) {
+        self.push(item);
+    }
+
+    #[inline]
+    fn extend_reserve(&mut self, additional: usize) {
+        self.reserve(additional);
+    }
+}
+
+impl<T, A: Allocator> Vec<T, A> {
+    // leaf method to which various SpecFrom/SpecExtend implementations delegate when
+    // they have no further optimizations to apply
+    #[cfg(not(no_global_oom_handling))]
+    fn extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) {
+        // This is the case for a general iterator.
+        //
+        // This function should be the moral equivalent of:
+        //
+        //      for item in iterator {
+        //          self.push(item);
+        //      }
+        while let Some(element) = iterator.next() {
+            let len = self.len();
+            if len == self.capacity() {
+                let (lower, _) = iterator.size_hint();
+                self.reserve(lower.saturating_add(1));
+            }
+            unsafe {
+                ptr::write(self.as_mut_ptr().add(len), element);
+                // Since next() executes user code which can panic we have to bump the length
+                // after each step.
+                // NB can't overflow since we would have had to alloc the address space
+                self.set_len(len + 1);
+            }
+        }
+    }
+
+    // leaf method to which various SpecFrom/SpecExtend implementations delegate when
+    // they have no further optimizations to apply
+    fn try_extend_desugared<I: Iterator<Item = T>>(&mut self, mut iterator: I) -> Result<(), TryReserveError> {
+        // This is the case for a general iterator.
+        //
+        // This function should be the moral equivalent of:
+        //
+        //      for item in iterator {
+        //          self.push(item);
+        //      }
+        while let Some(element) = iterator.next() {
+            let len = self.len();
+            if len == self.capacity() {
+                let (lower, _) = iterator.size_hint();
+                self.try_reserve(lower.saturating_add(1))?;
+            }
+            unsafe {
+                ptr::write(self.as_mut_ptr().add(len), element);
+                // Since next() executes user code which can panic we have to bump the length
+                // after each step.
+                // NB can't overflow since we would have had to alloc the address space
+                self.set_len(len + 1);
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Creates a splicing iterator that replaces the specified range in the vector
+    /// with the given `replace_with` iterator and yields the removed items.
+    /// `replace_with` does not need to be the same length as `range`.
+    ///
+    /// `range` is removed even if the iterator is not consumed until the end.
+    ///
+    /// It is unspecified how many elements are removed from the vector
+    /// if the `Splice` value is leaked.
+    ///
+    /// The input iterator `replace_with` is only consumed when the `Splice` value is dropped.
+    ///
+    /// This is optimal if:
+    ///
+    /// * The tail (elements in the vector after `range`) is empty,
+    /// * or `replace_with` yields fewer or equal elements than `range`’s length
+    /// * or the lower bound of its `size_hint()` is exact.
+    ///
+    /// Otherwise, a temporary vector is allocated and the tail is moved twice.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the starting point is greater than the end point or if
+    /// the end point is greater than the length of the vector.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let mut v = vec![1, 2, 3, 4];
+    /// let new = [7, 8, 9];
+    /// let u: Vec<_> = v.splice(1..3, new).collect();
+    /// assert_eq!(v, &[1, 7, 8, 9, 4]);
+    /// assert_eq!(u, &[2, 3]);
+    /// ```
+    #[cfg(not(no_global_oom_handling))]
+    #[inline]
+    #[stable(feature = "vec_splice", since = "1.21.0")]
+    pub fn splice<R, I>(&mut self, range: R, replace_with: I) -> Splice<'_, I::IntoIter, A>
+    where
+        R: RangeBounds<usize>,
+        I: IntoIterator<Item = T>,
+    {
+        Splice { drain: self.drain(range), replace_with: replace_with.into_iter() }
+    }
+
+    /// Creates an iterator which uses a closure to determine if an element should be removed.
+    ///
+    /// If the closure returns true, then the element is removed and yielded.
+    /// If the closure returns false, the element will remain in the vector and will not be yielded
+    /// by the iterator.
+    ///
+    /// Using this method is equivalent to the following code:
+    ///
+    /// ```
+    /// # let some_predicate = |x: &mut i32| { *x == 2 || *x == 3 || *x == 6 };
+    /// # let mut vec = vec![1, 2, 3, 4, 5, 6];
+    /// let mut i = 0;
+    /// while i < vec.len() {
+    ///     if some_predicate(&mut vec[i]) {
+    ///         let val = vec.remove(i);
+    ///         // your code here
+    ///     } else {
+    ///         i += 1;
+    ///     }
+    /// }
+    ///
+    /// # assert_eq!(vec, vec![1, 4, 5]);
+    /// ```
+    ///
+    /// But `drain_filter` is easier to use. `drain_filter` is also more efficient,
+    /// because it can backshift the elements of the array in bulk.
+    ///
+    /// Note that `drain_filter` also lets you mutate every element in the filter closure,
+    /// regardless of whether you choose to keep or remove it.
+    ///
+    /// # Examples
+    ///
+    /// Splitting an array into evens and odds, reusing the original allocation:
+    ///
+    /// ```
+    /// #![feature(drain_filter)]
+    /// let mut numbers = vec![1, 2, 3, 4, 5, 6, 8, 9, 11, 13, 14, 15];
+    ///
+    /// let evens = numbers.drain_filter(|x| *x % 2 == 0).collect::<Vec<_>>();
+    /// let odds = numbers;
+    ///
+    /// assert_eq!(evens, vec![2, 4, 6, 8, 14]);
+    /// assert_eq!(odds, vec![1, 3, 5, 9, 11, 13, 15]);
+    /// ```
+    #[unstable(feature = "drain_filter", reason = "recently added", issue = "43244")]
+    pub fn drain_filter<F>(&mut self, filter: F) -> DrainFilter<'_, T, F, A>
+    where
+        F: FnMut(&mut T) -> bool,
+    {
+        let old_len = self.len();
+
+        // Guard against us getting leaked (leak amplification)
+        unsafe {
+            self.set_len(0);
+        }
+
+        DrainFilter { vec: self, idx: 0, del: 0, old_len, pred: filter, panic_flag: false }
+    }
+}
+
+/// Extend implementation that copies elements out of references before pushing them onto the Vec.
+///
+/// This implementation is specialized for slice iterators, where it uses [`copy_from_slice`] to
+/// append the entire slice at once.
+///
+/// [`copy_from_slice`]: slice::copy_from_slice
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "extend_ref", since = "1.2.0")]
+impl<'a, T: Copy + 'a, A: Allocator + 'a> Extend<&'a T> for Vec<T, A> {
+    fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) {
+        self.spec_extend(iter.into_iter())
+    }
+
+    #[inline]
+    fn extend_one(&mut self, &item: &'a T) {
+        self.push(item);
+    }
+
+    #[inline]
+    fn extend_reserve(&mut self, additional: usize) {
+        self.reserve(additional);
+    }
+}
+
+/// Implements comparison of vectors, [lexicographically](core::cmp::Ord#lexicographical-comparison).
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: PartialOrd, A: Allocator> PartialOrd for Vec<T, A> {
+    #[inline]
+    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
+        PartialOrd::partial_cmp(&**self, &**other)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Eq, A: Allocator> Eq for Vec<T, A> {}
+
+/// Implements ordering of vectors, [lexicographically](core::cmp::Ord#lexicographical-comparison).
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Ord, A: Allocator> Ord for Vec<T, A> {
+    #[inline]
+    fn cmp(&self, other: &Self) -> Ordering {
+        Ord::cmp(&**self, &**other)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+unsafe impl<#[may_dangle] T, A: Allocator> Drop for Vec<T, A> {
+    fn drop(&mut self) {
+        unsafe {
+            // use drop for [T]
+            // use a raw slice to refer to the elements of the vector as weakest necessary type;
+            // could avoid questions of validity in certain cases
+            ptr::drop_in_place(ptr::slice_from_raw_parts_mut(self.as_mut_ptr(), self.len))
+        }
+        // RawVec handles deallocation
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+#[rustc_const_unstable(feature = "const_default_impls", issue = "87864")]
+impl<T> const Default for Vec<T> {
+    /// Creates an empty `Vec<T>`.
+    fn default() -> Vec<T> {
+        Vec::new()
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: fmt::Debug, A: Allocator> fmt::Debug for Vec<T, A> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        fmt::Debug::fmt(&**self, f)
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> AsRef<Vec<T, A>> for Vec<T, A> {
+    fn as_ref(&self) -> &Vec<T, A> {
+        self
+    }
+}
+
+#[stable(feature = "vec_as_mut", since = "1.5.0")]
+impl<T, A: Allocator> AsMut<Vec<T, A>> for Vec<T, A> {
+    fn as_mut(&mut self) -> &mut Vec<T, A> {
+        self
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T, A: Allocator> AsRef<[T]> for Vec<T, A> {
+    fn as_ref(&self) -> &[T] {
+        self
+    }
+}
+
+#[stable(feature = "vec_as_mut", since = "1.5.0")]
+impl<T, A: Allocator> AsMut<[T]> for Vec<T, A> {
+    fn as_mut(&mut self) -> &mut [T] {
+        self
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: Clone> From<&[T]> for Vec<T> {
+    /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Vec::from(&[1, 2, 3][..]), vec![1, 2, 3]);
+    /// ```
+    #[cfg(not(test))]
+    fn from(s: &[T]) -> Vec<T> {
+        s.to_vec()
+    }
+    #[cfg(test)]
+    fn from(s: &[T]) -> Vec<T> {
+        crate::slice::to_vec(s, Global)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_from_mut", since = "1.19.0")]
+impl<T: Clone> From<&mut [T]> for Vec<T> {
+    /// Allocate a `Vec<T>` and fill it by cloning `s`'s items.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Vec::from(&mut [1, 2, 3][..]), vec![1, 2, 3]);
+    /// ```
+    #[cfg(not(test))]
+    fn from(s: &mut [T]) -> Vec<T> {
+        s.to_vec()
+    }
+    #[cfg(test)]
+    fn from(s: &mut [T]) -> Vec<T> {
+        crate::slice::to_vec(s, Global)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "vec_from_array", since = "1.44.0")]
+impl<T, const N: usize> From<[T; N]> for Vec<T> {
+    /// Allocate a `Vec<T>` and move `s`'s items into it.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Vec::from([1, 2, 3]), vec![1, 2, 3]);
+    /// ```
+    #[cfg(not(test))]
+    fn from(s: [T; N]) -> Vec<T> {
+        <[T]>::into_vec(box s)
+    }
+
+    #[cfg(test)]
+    fn from(s: [T; N]) -> Vec<T> {
+        crate::slice::into_vec(box s)
+    }
+}
+
+#[stable(feature = "vec_from_cow_slice", since = "1.14.0")]
+impl<'a, T> From<Cow<'a, [T]>> for Vec<T>
+where
+    [T]: ToOwned<Owned = Vec<T>>,
+{
+    /// Convert a clone-on-write slice into a vector.
+    ///
+    /// If `s` already owns a `Vec<T>`, it will be returned directly.
+    /// If `s` is borrowing a slice, a new `Vec<T>` will be allocated and
+    /// filled by cloning `s`'s items into it.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # use std::borrow::Cow;
+    /// let o: Cow<[i32]> = Cow::Owned(vec![1, 2, 3]);
+    /// let b: Cow<[i32]> = Cow::Borrowed(&[1, 2, 3]);
+    /// assert_eq!(Vec::from(o), Vec::from(b));
+    /// ```
+    fn from(s: Cow<'a, [T]>) -> Vec<T> {
+        s.into_owned()
+    }
+}
+
+// note: test pulls in libstd, which causes errors here
+#[cfg(not(test))]
+#[stable(feature = "vec_from_box", since = "1.18.0")]
+impl<T, A: Allocator> From<Box<[T], A>> for Vec<T, A> {
+    /// Convert a boxed slice into a vector by transferring ownership of
+    /// the existing heap allocation.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// let b: Box<[i32]> = vec![1, 2, 3].into_boxed_slice();
+    /// assert_eq!(Vec::from(b), vec![1, 2, 3]);
+    /// ```
+    fn from(s: Box<[T], A>) -> Self {
+        s.into_vec()
+    }
+}
+
+// note: test pulls in libstd, which causes errors here
+#[cfg(not(no_global_oom_handling))]
+#[cfg(not(test))]
+#[stable(feature = "box_from_vec", since = "1.20.0")]
+impl<T, A: Allocator> From<Vec<T, A>> for Box<[T], A> {
+    /// Convert a vector into a boxed slice.
+    ///
+    /// If `v` has excess capacity, its items will be moved into a
+    /// newly-allocated buffer with exactly the right capacity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Box::from(vec![1, 2, 3]), vec![1, 2, 3].into_boxed_slice());
+    /// ```
+    fn from(v: Vec<T, A>) -> Self {
+        v.into_boxed_slice()
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+#[stable(feature = "rust1", since = "1.0.0")]
+impl From<&str> for Vec<u8> {
+    /// Allocate a `Vec<u8>` and fill it with a UTF-8 string.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(Vec::from("123"), vec![b'1', b'2', b'3']);
+    /// ```
+    fn from(s: &str) -> Vec<u8> {
+        From::from(s.as_bytes())
+    }
+}
+
+#[stable(feature = "array_try_from_vec", since = "1.48.0")]
+impl<T, A: Allocator, const N: usize> TryFrom<Vec<T, A>> for [T; N] {
+    type Error = Vec<T, A>;
+
+    /// Gets the entire contents of the `Vec<T>` as an array,
+    /// if its size exactly matches that of the requested array.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// assert_eq!(vec![1, 2, 3].try_into(), Ok([1, 2, 3]));
+    /// assert_eq!(<Vec<i32>>::new().try_into(), Ok([]));
+    /// ```
+    ///
+    /// If the length doesn't match, the input comes back in `Err`:
+    /// ```
+    /// let r: Result<[i32; 4], _> = (0..10).collect::<Vec<_>>().try_into();
+    /// assert_eq!(r, Err(vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9]));
+    /// ```
+    ///
+    /// If you're fine with just getting a prefix of the `Vec<T>`,
+    /// you can call [`.truncate(N)`](Vec::truncate) first.
+    /// ```
+    /// let mut v = String::from("hello world").into_bytes();
+    /// v.sort();
+    /// v.truncate(2);
+    /// let [a, b]: [_; 2] = v.try_into().unwrap();
+    /// assert_eq!(a, b' ');
+    /// assert_eq!(b, b'd');
+    /// ```
+    fn try_from(mut vec: Vec<T, A>) -> Result<[T; N], Vec<T, A>> {
+        if vec.len() != N {
+            return Err(vec);
+        }
+
+        // SAFETY: `.set_len(0)` is always sound.
+        unsafe { vec.set_len(0) };
+
+        // SAFETY: A `Vec`'s pointer is always aligned properly, and
+        // the alignment the array needs is the same as the items.
+        // We checked earlier that we have sufficient items.
+        // The items will not double-drop as the `set_len`
+        // tells the `Vec` not to also drop them.
+        let array = unsafe { ptr::read(vec.as_ptr() as *const [T; N]) };
+        Ok(array)
+    }
+}
diff --git a/rust/alloc/vec/partial_eq.rs b/rust/alloc/vec/partial_eq.rs
new file mode 100644
index 000000000000..10ad4e492287
--- /dev/null
+++ b/rust/alloc/vec/partial_eq.rs
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use crate::alloc::Allocator;
+#[cfg(not(no_global_oom_handling))]
+use crate::borrow::Cow;
+
+use super::Vec;
+
+macro_rules! __impl_slice_eq1 {
+    ([$($vars:tt)*] $lhs:ty, $rhs:ty $(where $ty:ty: $bound:ident)?, #[$stability:meta]) => {
+        #[$stability]
+        impl<T, U, $($vars)*> PartialEq<$rhs> for $lhs
+        where
+            T: PartialEq<U>,
+            $($ty: $bound)?
+        {
+            #[inline]
+            fn eq(&self, other: &$rhs) -> bool { self[..] == other[..] }
+            #[inline]
+            fn ne(&self, other: &$rhs) -> bool { self[..] != other[..] }
+        }
+    }
+}
+
+__impl_slice_eq1! { [A1: Allocator, A2: Allocator] Vec<T, A1>, Vec<U, A2>, #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator] Vec<T, A>, &[U], #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator] Vec<T, A>, &mut [U], #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator] &[T], Vec<U, A>, #[stable(feature = "partialeq_vec_for_ref_slice", since = "1.46.0")] }
+__impl_slice_eq1! { [A: Allocator] &mut [T], Vec<U, A>, #[stable(feature = "partialeq_vec_for_ref_slice", since = "1.46.0")] }
+__impl_slice_eq1! { [A: Allocator] Vec<T, A>, [U], #[stable(feature = "partialeq_vec_for_slice", since = "1.48.0")]  }
+__impl_slice_eq1! { [A: Allocator] [T], Vec<U, A>, #[stable(feature = "partialeq_vec_for_slice", since = "1.48.0")]  }
+#[cfg(not(no_global_oom_handling))]
+__impl_slice_eq1! { [A: Allocator] Cow<'_, [T]>, Vec<U, A> where T: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
+#[cfg(not(no_global_oom_handling))]
+__impl_slice_eq1! { [] Cow<'_, [T]>, &[U] where T: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
+#[cfg(not(no_global_oom_handling))]
+__impl_slice_eq1! { [] Cow<'_, [T]>, &mut [U] where T: Clone, #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator, const N: usize] Vec<T, A>, [U; N], #[stable(feature = "rust1", since = "1.0.0")] }
+__impl_slice_eq1! { [A: Allocator, const N: usize] Vec<T, A>, &[U; N], #[stable(feature = "rust1", since = "1.0.0")] }
+
+// NOTE: some less important impls are omitted to reduce code bloat
+// FIXME(Centril): Reconsider this?
+//__impl_slice_eq1! { [const N: usize] Vec<A>, &mut [B; N], }
+//__impl_slice_eq1! { [const N: usize] [A; N], Vec<B>, }
+//__impl_slice_eq1! { [const N: usize] &[A; N], Vec<B>, }
+//__impl_slice_eq1! { [const N: usize] &mut [A; N], Vec<B>, }
+//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, [B; N], }
+//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &[B; N], }
+//__impl_slice_eq1! { [const N: usize] Cow<'a, [A]>, &mut [B; N], }
diff --git a/rust/alloc/vec/set_len_on_drop.rs b/rust/alloc/vec/set_len_on_drop.rs
new file mode 100644
index 000000000000..448bf5076a0b
--- /dev/null
+++ b/rust/alloc/vec/set_len_on_drop.rs
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// Set the length of the vec when the `SetLenOnDrop` value goes out of scope.
+//
+// The idea is: The length field in SetLenOnDrop is a local variable
+// that the optimizer will see does not alias with any stores through the Vec's data
+// pointer. This is a workaround for alias analysis issue #32155
+pub(super) struct SetLenOnDrop<'a> {
+    len: &'a mut usize,
+    local_len: usize,
+}
+
+impl<'a> SetLenOnDrop<'a> {
+    #[inline]
+    pub(super) fn new(len: &'a mut usize) -> Self {
+        SetLenOnDrop { local_len: *len, len }
+    }
+
+    #[inline]
+    pub(super) fn increment_len(&mut self, increment: usize) {
+        self.local_len += increment;
+    }
+}
+
+impl Drop for SetLenOnDrop<'_> {
+    #[inline]
+    fn drop(&mut self) {
+        *self.len = self.local_len;
+    }
+}
diff --git a/rust/alloc/vec/spec_extend.rs b/rust/alloc/vec/spec_extend.rs
new file mode 100644
index 000000000000..5ce2d00991bc
--- /dev/null
+++ b/rust/alloc/vec/spec_extend.rs
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use crate::alloc::Allocator;
+use crate::collections::{TryReserveError, TryReserveErrorKind};
+use core::iter::TrustedLen;
+use core::ptr::{self};
+use core::slice::{self};
+
+use super::{IntoIter, SetLenOnDrop, Vec};
+
+// Specialization trait used for Vec::extend
+#[cfg(not(no_global_oom_handling))]
+pub(super) trait SpecExtend<T, I> {
+    fn spec_extend(&mut self, iter: I);
+}
+
+// Specialization trait used for Vec::try_extend
+pub(super) trait TrySpecExtend<T, I> {
+    fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError>;
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
+where
+    I: Iterator<Item = T>,
+{
+    default fn spec_extend(&mut self, iter: I) {
+        self.extend_desugared(iter)
+    }
+}
+
+impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
+where
+    I: Iterator<Item = T>,
+{
+    default fn try_spec_extend(&mut self, iter: I) -> Result<(), TryReserveError> {
+        self.try_extend_desugared(iter)
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T, I, A: Allocator> SpecExtend<T, I> for Vec<T, A>
+where
+    I: TrustedLen<Item = T>,
+{
+    default fn spec_extend(&mut self, iterator: I) {
+        // This is the case for a TrustedLen iterator.
+        let (low, high) = iterator.size_hint();
+        if let Some(additional) = high {
+            debug_assert_eq!(
+                low,
+                additional,
+                "TrustedLen iterator's size hint is not exact: {:?}",
+                (low, high)
+            );
+            self.reserve(additional);
+            unsafe {
+                let mut ptr = self.as_mut_ptr().add(self.len());
+                let mut local_len = SetLenOnDrop::new(&mut self.len);
+                iterator.for_each(move |element| {
+                    ptr::write(ptr, element);
+                    ptr = ptr.offset(1);
+                    // Since the loop executes user code which can panic we have to bump the pointer
+                    // after each step.
+                    // NB can't overflow since we would have had to alloc the address space
+                    local_len.increment_len(1);
+                });
+            }
+        } else {
+            // Per TrustedLen contract a `None` upper bound means that the iterator length
+            // truly exceeds usize::MAX, which would eventually lead to a capacity overflow anyway.
+            // Since the other branch already panics eagerly (via `reserve()`) we do the same here.
+            // This avoids additional codegen for a fallback code path which would eventually
+            // panic anyway.
+            panic!("capacity overflow");
+        }
+    }
+}
+
+impl<T, I, A: Allocator> TrySpecExtend<T, I> for Vec<T, A>
+where
+    I: TrustedLen<Item = T>,
+{
+    default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
+        // This is the case for a TrustedLen iterator.
+        let (low, high) = iterator.size_hint();
+        if let Some(additional) = high {
+            debug_assert_eq!(
+                low,
+                additional,
+                "TrustedLen iterator's size hint is not exact: {:?}",
+                (low, high)
+            );
+            self.try_reserve(additional)?;
+            unsafe {
+                let mut ptr = self.as_mut_ptr().add(self.len());
+                let mut local_len = SetLenOnDrop::new(&mut self.len);
+                iterator.for_each(move |element| {
+                    ptr::write(ptr, element);
+                    ptr = ptr.offset(1);
+                    // Since the loop executes user code which can panic we have to bump the pointer
+                    // after each step.
+                    // NB can't overflow since we would have had to alloc the address space
+                    local_len.increment_len(1);
+                });
+            }
+            Ok(())
+        } else {
+            Err(TryReserveErrorKind::CapacityOverflow.into())
+        }
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<T, A: Allocator> SpecExtend<T, IntoIter<T>> for Vec<T, A> {
+    fn spec_extend(&mut self, mut iterator: IntoIter<T>) {
+        unsafe {
+            self.append_elements(iterator.as_slice() as _);
+        }
+        iterator.forget_remaining_elements();
+    }
+}
+
+impl<T, A: Allocator> TrySpecExtend<T, IntoIter<T>> for Vec<T, A> {
+    fn try_spec_extend(&mut self, mut iterator: IntoIter<T>) -> Result<(), TryReserveError> {
+        unsafe {
+            self.try_append_elements(iterator.as_slice() as _)?;
+        }
+        iterator.forget_remaining_elements();
+        Ok(())
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<'a, T: 'a, I, A: Allocator + 'a> SpecExtend<&'a T, I> for Vec<T, A>
+where
+    I: Iterator<Item = &'a T>,
+    T: Clone,
+{
+    default fn spec_extend(&mut self, iterator: I) {
+        self.spec_extend(iterator.cloned())
+    }
+}
+
+impl<'a, T: 'a, I, A: Allocator + 'a> TrySpecExtend<&'a T, I> for Vec<T, A>
+where
+    I: Iterator<Item = &'a T>,
+    T: Clone,
+{
+    default fn try_spec_extend(&mut self, iterator: I) -> Result<(), TryReserveError> {
+        self.try_spec_extend(iterator.cloned())
+    }
+}
+
+#[cfg(not(no_global_oom_handling))]
+impl<'a, T: 'a, A: Allocator + 'a> SpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
+where
+    T: Copy,
+{
+    fn spec_extend(&mut self, iterator: slice::Iter<'a, T>) {
+        let slice = iterator.as_slice();
+        unsafe { self.append_elements(slice) };
+    }
+}
+
+impl<'a, T: 'a, A: Allocator + 'a> TrySpecExtend<&'a T, slice::Iter<'a, T>> for Vec<T, A>
+where
+    T: Copy,
+{
+    fn try_spec_extend(&mut self, iterator: slice::Iter<'a, T>) -> Result<(), TryReserveError> {
+        let slice = iterator.as_slice();
+        unsafe { self.try_append_elements(slice) }
+    }
+}
diff --git a/rust/bindgen_parameters b/rust/bindgen_parameters
new file mode 100644
index 000000000000..be4963bf7203
--- /dev/null
+++ b/rust/bindgen_parameters
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0
+
+--opaque-type xregs_state
+--opaque-type desc_struct
+--opaque-type arch_lbr_state
+--opaque-type local_apic
+
+# Packed type cannot transitively contain a `#[repr(align)]` type.
+--opaque-type x86_msi_data
+--opaque-type x86_msi_addr_lo
+
+# `try` is a reserved keyword since Rust 2018; solved in `bindgen` v0.59.2,
+# commit 2aed6b021680 ("context: Escape the try keyword properly").
+--opaque-type kunit_try_catch
+
+# If SMP is disabled, `arch_spinlock_t` is defined as a ZST which triggers a Rust
+# warning. We don't need to peek into it anyway.
+--opaque-type spinlock
+
+# `seccomp`'s comment gets understood as a doctest
+--no-doc-comments
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
new file mode 100644
index 000000000000..284793085d55
--- /dev/null
+++ b/rust/bindings/bindings_helper.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Header that contains the code (mostly headers) for which Rust bindings
+ * will be automatically generated by `bindgen`.
+ *
+ * Sorted alphabetically.
+ */
+
+#include <kunit/test.h>
+#include <linux/amba/bus.h>
+#include <linux/cdev.h>
+#include <linux/clk.h>
+#include <linux/errname.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/fs_parser.h>
+#include <linux/gpio/driver.h>
+#include <linux/hw_random.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/netfilter_arp.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv6.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/poll.h>
+#include <linux/random.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/uaccess.h>
+#include <linux/uio.h>
+#include <uapi/linux/android/binder.h>
+
+/* `bindgen` gets confused at certain things. */
+const gfp_t BINDINGS_GFP_KERNEL = GFP_KERNEL;
+const gfp_t BINDINGS___GFP_ZERO = __GFP_ZERO;
+const __poll_t BINDINGS_EPOLLIN = EPOLLIN;
+const __poll_t BINDINGS_EPOLLOUT = EPOLLOUT;
+const __poll_t BINDINGS_EPOLLERR = EPOLLERR;
+const __poll_t BINDINGS_EPOLLHUP = EPOLLHUP;
+
+const loff_t BINDINGS_MAX_LFS_FILESIZE = MAX_LFS_FILESIZE;
diff --git a/rust/bindings/lib.rs b/rust/bindings/lib.rs
new file mode 100644
index 000000000000..7fdd74e68b60
--- /dev/null
+++ b/rust/bindings/lib.rs
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Bindings.
+//!
+//! Imports the generated bindings by `bindgen`.
+//!
+//! This crate may not be directly used. If you need a kernel C API that is
+//! not ported or wrapped in the `kernel` crate, then do so first instead of
+//! using this crate.
+
+#![no_std]
+#![feature(core_ffi_c)]
+// See <https://github.com/rust-lang/rust-bindgen/issues/1651>.
+#![cfg_attr(test, allow(deref_nullptr))]
+#![cfg_attr(test, allow(unaligned_references))]
+#![cfg_attr(test, allow(unsafe_op_in_unsafe_fn))]
+#![allow(
+    clippy::all,
+    missing_docs,
+    non_camel_case_types,
+    non_upper_case_globals,
+    non_snake_case,
+    improper_ctypes,
+    unreachable_pub,
+    unsafe_op_in_unsafe_fn
+)]
+
+mod bindings_raw {
+    // Use glob import here to expose all helpers.
+    // Symbols defined within the module will take precedence to the glob import.
+    pub use super::bindings_helper::*;
+    include!(concat!(
+        env!("OBJTREE"),
+        "/rust/bindings/bindings_generated.rs"
+    ));
+}
+
+// When both a directly exposed symbol and a helper exists for the same function,
+// the directly exposed symbol is preferred and the helper becomes dead code, so
+// ignore the warning here.
+#[allow(dead_code)]
+mod bindings_helper {
+    // Import the generated bindings for types.
+    use super::bindings_raw::*;
+    include!(concat!(
+        env!("OBJTREE"),
+        "/rust/bindings/bindings_helpers_generated.rs"
+    ));
+}
+
+pub use bindings_raw::*;
+
+pub const GFP_KERNEL: gfp_t = BINDINGS_GFP_KERNEL;
+pub const __GFP_ZERO: gfp_t = BINDINGS___GFP_ZERO;
+pub const __GFP_HIGHMEM: gfp_t = ___GFP_HIGHMEM;
+
+pub const MAX_LFS_FILESIZE: loff_t = BINDINGS_MAX_LFS_FILESIZE;
diff --git a/rust/build_error.rs b/rust/build_error.rs
new file mode 100644
index 000000000000..bbd3a05440b2
--- /dev/null
+++ b/rust/build_error.rs
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Build-time error.
+//!
+//! This crate provides a function `build_error`, which will panic in
+//! compile-time if executed in const context, and will cause a build error
+//! if not executed at compile time and the optimizer does not optimise away the
+//! call.
+//!
+//! It is used by `build_assert!` in the kernel crate, allowing checking of
+//! conditions that could be checked statically, but could not be enforced in
+//! Rust yet (e.g. perform some checks in const functions, but those
+//! functions could still be called in the runtime).
+
+#![no_std]
+
+/// Panics if executed in const context, or triggers a build error if not.
+#[inline(never)]
+#[cold]
+#[export_name = "rust_build_error"]
+#[track_caller]
+pub const fn build_error(msg: &'static str) -> ! {
+    panic!("{}", msg);
+}
+
+#[cfg(CONFIG_RUST_BUILD_ASSERT_WARN)]
+#[link_section = ".gnu.warning.rust_build_error"]
+#[used]
+static BUILD_ERROR_WARNING: [u8; 45] = *b"call to build_error present after compilation";
diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs
new file mode 100644
index 000000000000..e57011b7c3da
--- /dev/null
+++ b/rust/compiler_builtins.rs
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Our own `compiler_builtins`.
+//!
+//! Rust provides [`compiler_builtins`] as a port of LLVM's [`compiler-rt`].
+//! Since we do not need the vast majority of them, we avoid the dependency
+//! by providing this file.
+//!
+//! At the moment, some builtins are required that should not be. For instance,
+//! [`core`] has 128-bit integers functionality which we should not be compiling
+//! in. We will work with upstream [`core`] to provide feature flags to disable
+//! the parts we do not need. For the moment, we define them to [`panic!`] at
+//! runtime for simplicity to catch mistakes, instead of performing surgery
+//! on `core.o`.
+//!
+//! In any case, all these symbols are weakened to ensure we do not override
+//! those that may be provided by the rest of the kernel.
+//!
+//! [`compiler_builtins`]: https://github.com/rust-lang/compiler-builtins
+//! [`compiler-rt`]: https://compiler-rt.llvm.org/
+
+#![feature(compiler_builtins)]
+#![compiler_builtins]
+#![no_builtins]
+#![no_std]
+
+macro_rules! define_panicking_intrinsics(
+    ($reason: tt, { $($ident: ident, )* }) => {
+        $(
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern "C" fn $ident() {
+                panic!($reason);
+            }
+        )*
+    }
+);
+
+define_panicking_intrinsics!("`f32` should not be used", {
+    __eqsf2,
+    __gesf2,
+    __lesf2,
+    __nesf2,
+    __unordsf2,
+});
+
+define_panicking_intrinsics!("`f64` should not be used", {
+    __unorddf2,
+});
+
+define_panicking_intrinsics!("`i128` should not be used", {
+    __ashrti3,
+    __muloti4,
+    __multi3,
+});
+
+define_panicking_intrinsics!("`u128` should not be used", {
+    __ashlti3,
+    __lshrti3,
+    __udivmodti4,
+    __udivti3,
+    __umodti3,
+});
+
+#[cfg(target_arch = "arm")]
+define_panicking_intrinsics!("`f32` should not be used", {
+    __aeabi_fcmpeq,
+    __aeabi_fcmpun,
+});
+
+#[cfg(target_arch = "arm")]
+define_panicking_intrinsics!("`f64` should not be used", {
+    __aeabi_dcmpun,
+});
+
+#[cfg(target_arch = "arm")]
+define_panicking_intrinsics!("`u64` division/modulo should not be used", {
+    __aeabi_uldivmod,
+});
diff --git a/rust/exports.c b/rust/exports.c
new file mode 100644
index 000000000000..bb7cc64cecd0
--- /dev/null
+++ b/rust/exports.c
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * A hack to export Rust symbols for loadable modules without having to redo
+ * the entire `include/linux/export.h` logic in Rust.
+ *
+ * This requires the Rust's new/future `v0` mangling scheme because the default
+ * one ("legacy") uses invalid characters for C identifiers (thus we cannot use
+ * the `EXPORT_SYMBOL_*` macros).
+ *
+ * All symbols are exported as GPL-only to guarantee no GPL-only feature is
+ * accidentally exposed.
+ */
+
+#include <linux/module.h>
+
+#define EXPORT_SYMBOL_RUST_GPL(sym) extern int sym; EXPORT_SYMBOL_GPL(sym)
+
+#include "exports_core_generated.h"
+#include "exports_alloc_generated.h"
+#include "exports_bindings_generated.h"
+#include "exports_kernel_generated.h"
diff --git a/rust/helpers.c b/rust/helpers.c
new file mode 100644
index 000000000000..bf790f46c763
--- /dev/null
+++ b/rust/helpers.c
@@ -0,0 +1,679 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions
+ * cannot be called either. This file explicitly creates functions ("helpers")
+ * that wrap those so that they can be called from Rust.
+ *
+ * Even though Rust kernel modules should never use directly the bindings, some
+ * of these helpers need to be exported because Rust generics and inlined
+ * functions may not get their code generated in the crate where they are
+ * defined. Other helpers, called from non-inline functions, may not be
+ * exported, in principle. However, in general, the Rust compiler does not
+ * guarantee codegen will be performed for a non-inline function either.
+ * Therefore, this file exports all the helpers. In the future, this may be
+ * revisited to reduce the number of exports after the compiler is informed
+ * about the places codegen is required.
+ *
+ * All symbols are exported as GPL-only to guarantee no GPL-only feature is
+ * accidentally exposed.
+ */
+
+#include <linux/amba/bus.h>
+#include <linux/bug.h>
+#include <linux/build_bug.h>
+#include <linux/clk.h>
+#include <linux/errname.h>
+#include <linux/fs_parser.h>
+#include <linux/gfp.h>
+#include <linux/highmem.h>
+#include <linux/io.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/mutex.h>
+#include <linux/netdevice.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/sched/signal.h>
+#include <linux/security.h>
+#include <linux/skbuff.h>
+#include <linux/uaccess.h>
+#include <linux/uio.h>
+
+__noreturn void rust_helper_BUG(void)
+{
+	BUG();
+}
+EXPORT_SYMBOL_GPL(rust_helper_BUG);
+
+void rust_helper_clk_disable_unprepare(struct clk *clk)
+{
+	return clk_disable_unprepare(clk);
+}
+EXPORT_SYMBOL_GPL(rust_helper_clk_disable_unprepare);
+
+int rust_helper_clk_prepare_enable(struct clk *clk)
+{
+	return clk_prepare_enable(clk);
+}
+EXPORT_SYMBOL_GPL(rust_helper_clk_prepare_enable);
+
+unsigned long rust_helper_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+	return copy_from_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_from_user);
+
+unsigned long rust_helper_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+	return copy_to_user(to, from, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_to_user);
+
+unsigned long rust_helper_clear_user(void __user *to, unsigned long n)
+{
+	return clear_user(to, n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_clear_user);
+
+void __iomem *rust_helper_ioremap(resource_size_t offset, unsigned long size)
+{
+	return ioremap(offset, size);
+}
+EXPORT_SYMBOL_GPL(rust_helper_ioremap);
+
+u8 rust_helper_readb(const volatile void __iomem *addr)
+{
+	return readb(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readb);
+
+u16 rust_helper_readw(const volatile void __iomem *addr)
+{
+	return readw(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readw);
+
+u32 rust_helper_readl(const volatile void __iomem *addr)
+{
+	return readl(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readl);
+
+#ifdef CONFIG_64BIT
+u64 rust_helper_readq(const volatile void __iomem *addr)
+{
+	return readq(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readq);
+#endif
+
+void rust_helper_writeb(u8 value, volatile void __iomem *addr)
+{
+	writeb(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeb);
+
+void rust_helper_writew(u16 value, volatile void __iomem *addr)
+{
+	writew(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writew);
+
+void rust_helper_writel(u32 value, volatile void __iomem *addr)
+{
+	writel(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writel);
+
+#ifdef CONFIG_64BIT
+void rust_helper_writeq(u64 value, volatile void __iomem *addr)
+{
+	writeq(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeq);
+#endif
+
+u8 rust_helper_readb_relaxed(const volatile void __iomem *addr)
+{
+	return readb_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readb_relaxed);
+
+u16 rust_helper_readw_relaxed(const volatile void __iomem *addr)
+{
+	return readw_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readw_relaxed);
+
+u32 rust_helper_readl_relaxed(const volatile void __iomem *addr)
+{
+	return readl_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readl_relaxed);
+
+#ifdef CONFIG_64BIT
+u64 rust_helper_readq_relaxed(const volatile void __iomem *addr)
+{
+	return readq_relaxed(addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_readq_relaxed);
+#endif
+
+void rust_helper_writeb_relaxed(u8 value, volatile void __iomem *addr)
+{
+	writeb_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeb_relaxed);
+
+void rust_helper_writew_relaxed(u16 value, volatile void __iomem *addr)
+{
+	writew_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writew_relaxed);
+
+void rust_helper_writel_relaxed(u32 value, volatile void __iomem *addr)
+{
+	writel_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writel_relaxed);
+
+#ifdef CONFIG_64BIT
+void rust_helper_writeq_relaxed(u64 value, volatile void __iomem *addr)
+{
+	writeq_relaxed(value, addr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_writeq_relaxed);
+#endif
+
+void rust_helper_memcpy_fromio(void *to, const volatile void __iomem *from, long count)
+{
+	memcpy_fromio(to, from, count);
+}
+EXPORT_SYMBOL_GPL(rust_helper_memcpy_fromio);
+
+void rust_helper___spin_lock_init(spinlock_t *lock, const char *name,
+				  struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+	__spin_lock_init(lock, name, key);
+#else
+	spin_lock_init(lock);
+#endif
+}
+EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init);
+
+void rust_helper_spin_lock(spinlock_t *lock)
+{
+	spin_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_lock);
+
+void rust_helper_spin_unlock(spinlock_t *lock)
+{
+	spin_unlock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_unlock);
+
+unsigned long rust_helper_spin_lock_irqsave(spinlock_t *lock)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(lock, flags);
+
+	return flags;
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_lock_irqsave);
+
+void rust_helper_spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
+{
+	spin_unlock_irqrestore(lock, flags);
+}
+EXPORT_SYMBOL_GPL(rust_helper_spin_unlock_irqrestore);
+
+void rust_helper__raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
+				     struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_SPINLOCK
+	_raw_spin_lock_init(lock, name, key);
+#else
+	raw_spin_lock_init(lock);
+#endif
+}
+EXPORT_SYMBOL_GPL(rust_helper__raw_spin_lock_init);
+
+void rust_helper_raw_spin_lock(raw_spinlock_t *lock)
+{
+	raw_spin_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_lock);
+
+void rust_helper_raw_spin_unlock(raw_spinlock_t *lock)
+{
+	raw_spin_unlock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_unlock);
+
+unsigned long rust_helper_raw_spin_lock_irqsave(raw_spinlock_t *lock)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(lock, flags);
+
+	return flags;
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_lock_irqsave);
+
+void rust_helper_raw_spin_unlock_irqrestore(raw_spinlock_t *lock,
+					    unsigned long flags)
+{
+	raw_spin_unlock_irqrestore(lock, flags);
+}
+EXPORT_SYMBOL_GPL(rust_helper_raw_spin_unlock_irqrestore);
+
+void rust_helper_init_wait(struct wait_queue_entry *wq_entry)
+{
+	init_wait(wq_entry);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_wait);
+
+void rust_helper_init_waitqueue_func_entry(struct wait_queue_entry *wq_entry,
+					   wait_queue_func_t func)
+{
+	init_waitqueue_func_entry(wq_entry, func);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_waitqueue_func_entry);
+
+int rust_helper_signal_pending(struct task_struct *t)
+{
+	return signal_pending(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_signal_pending);
+
+struct page *rust_helper_alloc_pages(gfp_t gfp_mask, unsigned int order)
+{
+	return alloc_pages(gfp_mask, order);
+}
+EXPORT_SYMBOL_GPL(rust_helper_alloc_pages);
+
+void *rust_helper_kmap(struct page *page)
+{
+	return kmap(page);
+}
+EXPORT_SYMBOL_GPL(rust_helper_kmap);
+
+void rust_helper_kunmap(struct page *page)
+{
+	return kunmap(page);
+}
+EXPORT_SYMBOL_GPL(rust_helper_kunmap);
+
+int rust_helper_cond_resched(void)
+{
+	return cond_resched();
+}
+EXPORT_SYMBOL_GPL(rust_helper_cond_resched);
+
+size_t rust_helper_copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
+{
+	return copy_from_iter(addr, bytes, i);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_from_iter);
+
+size_t rust_helper_copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
+{
+	return copy_to_iter(addr, bytes, i);
+}
+EXPORT_SYMBOL_GPL(rust_helper_copy_to_iter);
+
+bool rust_helper_IS_ERR(__force const void *ptr)
+{
+	return IS_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_IS_ERR);
+
+long rust_helper_PTR_ERR(__force const void *ptr)
+{
+	return PTR_ERR(ptr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR);
+
+const char *rust_helper_errname(int err)
+{
+	return errname(err);
+}
+EXPORT_SYMBOL_GPL(rust_helper_errname);
+
+void rust_helper_mutex_lock(struct mutex *lock)
+{
+	mutex_lock(lock);
+}
+EXPORT_SYMBOL_GPL(rust_helper_mutex_lock);
+
+void rust_helper_amba_set_drvdata(struct amba_device *dev, void *data)
+{
+	amba_set_drvdata(dev, data);
+}
+EXPORT_SYMBOL_GPL(rust_helper_amba_set_drvdata);
+
+void *rust_helper_amba_get_drvdata(struct amba_device *dev)
+{
+	return amba_get_drvdata(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_amba_get_drvdata);
+
+void *
+rust_helper_platform_get_drvdata(const struct platform_device *pdev)
+{
+	return platform_get_drvdata(pdev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_platform_get_drvdata);
+
+void
+rust_helper_platform_set_drvdata(struct platform_device *pdev,
+				 void *data)
+{
+	return platform_set_drvdata(pdev, data);
+}
+EXPORT_SYMBOL_GPL(rust_helper_platform_set_drvdata);
+
+refcount_t rust_helper_REFCOUNT_INIT(int n)
+{
+	return (refcount_t)REFCOUNT_INIT(n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT);
+
+void rust_helper_refcount_inc(refcount_t *r)
+{
+	refcount_inc(r);
+}
+EXPORT_SYMBOL_GPL(rust_helper_refcount_inc);
+
+bool rust_helper_refcount_dec_and_test(refcount_t *r)
+{
+	return refcount_dec_and_test(r);
+}
+EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test);
+
+void rust_helper_rb_link_node(struct rb_node *node, struct rb_node *parent,
+			      struct rb_node **rb_link)
+{
+	rb_link_node(node, parent, rb_link);
+}
+EXPORT_SYMBOL_GPL(rust_helper_rb_link_node);
+
+struct task_struct *rust_helper_get_current(void)
+{
+	return current;
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_current);
+
+void rust_helper_get_task_struct(struct task_struct *t)
+{
+	get_task_struct(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_task_struct);
+
+void rust_helper_put_task_struct(struct task_struct *t)
+{
+	put_task_struct(t);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_task_struct);
+
+int rust_helper_security_binder_set_context_mgr(const struct cred *mgr)
+{
+	return security_binder_set_context_mgr(mgr);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_set_context_mgr);
+
+int rust_helper_security_binder_transaction(const struct cred *from,
+					    const struct cred *to)
+{
+	return security_binder_transaction(from, to);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_transaction);
+
+int rust_helper_security_binder_transfer_binder(const struct cred *from,
+						const struct cred *to)
+{
+	return security_binder_transfer_binder(from, to);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_transfer_binder);
+
+int rust_helper_security_binder_transfer_file(const struct cred *from,
+					      const struct cred *to,
+					      struct file *file)
+{
+	return security_binder_transfer_file(from, to, file);
+}
+EXPORT_SYMBOL_GPL(rust_helper_security_binder_transfer_file);
+
+struct file *rust_helper_get_file(struct file *f)
+{
+	return get_file(f);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_file);
+
+void rust_helper_rcu_read_lock(void)
+{
+	rcu_read_lock();
+}
+EXPORT_SYMBOL_GPL(rust_helper_rcu_read_lock);
+
+void rust_helper_rcu_read_unlock(void)
+{
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(rust_helper_rcu_read_unlock);
+
+void rust_helper_synchronize_rcu(void)
+{
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(rust_helper_synchronize_rcu);
+
+void *rust_helper_dev_get_drvdata(struct device *dev)
+{
+	return dev_get_drvdata(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_get_drvdata);
+
+const char *rust_helper_dev_name(const struct device *dev)
+{
+	return dev_name(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_name);
+
+void rust_helper___seqcount_init(seqcount_t *s, const char *name,
+				 struct lock_class_key *key)
+{
+	__seqcount_init(s, name, key);
+}
+EXPORT_SYMBOL_GPL(rust_helper___seqcount_init);
+
+unsigned rust_helper_read_seqcount_begin(seqcount_t *s)
+{
+	return read_seqcount_begin(s);
+}
+EXPORT_SYMBOL_GPL(rust_helper_read_seqcount_begin);
+
+int rust_helper_read_seqcount_retry(seqcount_t *s, unsigned start)
+{
+	return read_seqcount_retry(s, start);
+}
+EXPORT_SYMBOL_GPL(rust_helper_read_seqcount_retry);
+
+void rust_helper_write_seqcount_begin(seqcount_t *s)
+{
+	do_write_seqcount_begin(s);
+}
+EXPORT_SYMBOL_GPL(rust_helper_write_seqcount_begin);
+
+void rust_helper_write_seqcount_end(seqcount_t *s)
+{
+	do_write_seqcount_end(s);
+}
+EXPORT_SYMBOL_GPL(rust_helper_write_seqcount_end);
+
+void rust_helper_irq_set_handler_locked(struct irq_data *data,
+					irq_flow_handler_t handler)
+{
+	irq_set_handler_locked(data, handler);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_set_handler_locked);
+
+void *rust_helper_irq_data_get_irq_chip_data(struct irq_data *d)
+{
+	return irq_data_get_irq_chip_data(d);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_data_get_irq_chip_data);
+
+struct irq_chip *rust_helper_irq_desc_get_chip(struct irq_desc *desc)
+{
+	return irq_desc_get_chip(desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_desc_get_chip);
+
+void *rust_helper_irq_desc_get_handler_data(struct irq_desc *desc)
+{
+	return irq_desc_get_handler_data(desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_irq_desc_get_handler_data);
+
+void rust_helper_chained_irq_enter(struct irq_chip *chip,
+				   struct irq_desc *desc)
+{
+	chained_irq_enter(chip, desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_chained_irq_enter);
+
+void rust_helper_chained_irq_exit(struct irq_chip *chip,
+				   struct irq_desc *desc)
+{
+	chained_irq_exit(chip, desc);
+}
+EXPORT_SYMBOL_GPL(rust_helper_chained_irq_exit);
+
+const struct cred *rust_helper_get_cred(const struct cred *cred)
+{
+	return get_cred(cred);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_cred);
+
+void rust_helper_put_cred(const struct cred *cred)
+{
+	put_cred(cred);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_cred);
+
+const struct of_device_id *rust_helper_of_match_device(
+		const struct of_device_id *matches, const struct device *dev)
+{
+	return of_match_device(matches, dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_of_match_device);
+
+void rust_helper_init_completion(struct completion *c)
+{
+	init_completion(c);
+}
+EXPORT_SYMBOL_GPL(rust_helper_init_completion);
+
+struct sk_buff *rust_helper_skb_get(struct sk_buff *skb)
+{
+	return skb_get(skb);
+}
+EXPORT_SYMBOL_GPL(rust_helper_skb_get);
+
+unsigned int rust_helper_skb_headlen(const struct sk_buff *skb)
+{
+	return skb_headlen(skb);
+}
+EXPORT_SYMBOL_GPL(rust_helper_skb_headlen);
+
+void rust_helper_dev_hold(struct net_device *dev)
+{
+	return dev_hold(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_hold);
+
+void rust_helper_dev_put(struct net_device *dev)
+{
+	return dev_put(dev);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dev_put);
+
+struct net *rust_helper_get_net(struct net *net)
+{
+	return get_net(net);
+}
+EXPORT_SYMBOL_GPL(rust_helper_get_net);
+
+void rust_helper_put_net(struct net *net)
+{
+	return put_net(net);
+}
+EXPORT_SYMBOL_GPL(rust_helper_put_net);
+
+unsigned int rust_helper_NF_QUEUE_NR(unsigned int n)
+{
+	return NF_QUEUE_NR(n);
+}
+EXPORT_SYMBOL_GPL(rust_helper_NF_QUEUE_NR);
+
+void rust_helper___INIT_WORK_WITH_KEY(struct work_struct *work,
+		work_func_t func, bool on_stack, struct lock_class_key *key)
+{
+	__INIT_WORK_WITH_KEY(work, func, on_stack, key);
+}
+EXPORT_SYMBOL_GPL(rust_helper___INIT_WORK_WITH_KEY);
+
+struct dentry *rust_helper_dget(struct dentry *dentry)
+{
+	return dget(dentry);
+}
+EXPORT_SYMBOL_GPL(rust_helper_dget);
+
+void rust_helper_lockdep_register_key(struct lock_class_key *key)
+{
+	lockdep_register_key(key);
+}
+EXPORT_SYMBOL_GPL(rust_helper_lockdep_register_key);
+
+void rust_helper_lockdep_unregister_key(struct lock_class_key *key)
+{
+	lockdep_unregister_key(key);
+}
+EXPORT_SYMBOL_GPL(rust_helper_lockdep_unregister_key);
+
+int rust_helper_fs_parse(struct fs_context *fc,
+		const struct fs_parameter_spec *desc,
+		struct fs_parameter *param,
+		struct fs_parse_result *result)
+{
+	return fs_parse(fc, desc, param, result);
+}
+EXPORT_SYMBOL_GPL(rust_helper_fs_parse);
+
+/*
+ * We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type
+ * as the Rust `usize` type, so we can use it in contexts where Rust
+ * expects a `usize` like slice (array) indices. `usize` is defined to be
+ * the same as C's `uintptr_t` type (can hold any pointer) but not
+ * necessarily the same as `size_t` (can hold the size of any single
+ * object). Most modern platforms use the same concrete integer type for
+ * both of them, but in case we find ourselves on a platform where
+ * that's not true, fail early instead of risking ABI or
+ * integer-overflow issues.
+ *
+ * If your platform fails this assertion, it means that you are in
+ * danger of integer-overflow bugs (even if you attempt to remove
+ * `--size_t-is-usize`). It may be easiest to change the kernel ABI on
+ * your platform such that `size_t` matches `uintptr_t` (i.e., to increase
+ * `size_t`, because `uintptr_t` has to be at least as big as `size_t`).
+ */
+static_assert(
+	sizeof(size_t) == sizeof(uintptr_t) &&
+	__alignof__(size_t) == __alignof__(uintptr_t),
+	"Rust code expects C `size_t` to match Rust `usize`"
+);
diff --git a/rust/kernel/allocator.rs b/rust/kernel/allocator.rs
new file mode 100644
index 000000000000..397a3dd57a9b
--- /dev/null
+++ b/rust/kernel/allocator.rs
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Allocator support.
+
+use core::alloc::{GlobalAlloc, Layout};
+use core::ptr;
+
+use crate::bindings;
+
+struct KernelAllocator;
+
+unsafe impl GlobalAlloc for KernelAllocator {
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        // `krealloc()` is used instead of `kmalloc()` because the latter is
+        // an inline function and cannot be bound to as a result.
+        unsafe { bindings::krealloc(ptr::null(), layout.size(), bindings::GFP_KERNEL) as *mut u8 }
+    }
+
+    unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
+        unsafe {
+            bindings::kfree(ptr as *const core::ffi::c_void);
+        }
+    }
+}
+
+#[global_allocator]
+static ALLOCATOR: KernelAllocator = KernelAllocator;
+
+// `rustc` only generates these for some crate types. Even then, we would need
+// to extract the object file that has them from the archive. For the moment,
+// let's generate them ourselves instead.
+//
+// Note that `#[no_mangle]` implies exported too, nowadays.
+#[no_mangle]
+fn __rust_alloc(size: usize, _align: usize) -> *mut u8 {
+    unsafe { bindings::krealloc(core::ptr::null(), size, bindings::GFP_KERNEL) as *mut u8 }
+}
+
+#[no_mangle]
+fn __rust_dealloc(ptr: *mut u8, _size: usize, _align: usize) {
+    unsafe { bindings::kfree(ptr as *const core::ffi::c_void) };
+}
+
+#[no_mangle]
+fn __rust_realloc(ptr: *mut u8, _old_size: usize, _align: usize, new_size: usize) -> *mut u8 {
+    unsafe {
+        bindings::krealloc(
+            ptr as *const core::ffi::c_void,
+            new_size,
+            bindings::GFP_KERNEL,
+        ) as *mut u8
+    }
+}
+
+#[no_mangle]
+fn __rust_alloc_zeroed(size: usize, _align: usize) -> *mut u8 {
+    unsafe {
+        bindings::krealloc(
+            core::ptr::null(),
+            size,
+            bindings::GFP_KERNEL | bindings::__GFP_ZERO,
+        ) as *mut u8
+    }
+}
diff --git a/rust/kernel/amba.rs b/rust/kernel/amba.rs
new file mode 100644
index 000000000000..ec8808124a29
--- /dev/null
+++ b/rust/kernel/amba.rs
@@ -0,0 +1,261 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Amba devices and drivers.
+//!
+//! C header: [`include/linux/amba/bus.h`](../../../../include/linux/amba/bus.h)
+
+use crate::{
+    bindings, device, driver, error::from_kernel_result, io_mem::Resource, power, str::CStr,
+    to_result, types::PointerWrapper, Result, ThisModule,
+};
+
+/// A registration of an amba driver.
+pub type Registration<T> = driver::Registration<Adapter<T>>;
+
+/// Id of an Amba device.
+#[derive(Clone, Copy)]
+pub struct DeviceId {
+    /// Device id.
+    pub id: u32,
+
+    /// Mask that identifies which bits are valid in the device id.
+    pub mask: u32,
+}
+
+// SAFETY: `ZERO` is all zeroed-out and `to_rawid` stores `offset` in `amba_id::data`.
+unsafe impl const driver::RawDeviceId for DeviceId {
+    type RawType = bindings::amba_id;
+    const ZERO: Self::RawType = bindings::amba_id {
+        id: 0,
+        mask: 0,
+        data: core::ptr::null_mut(),
+    };
+
+    fn to_rawid(&self, offset: isize) -> Self::RawType {
+        bindings::amba_id {
+            id: self.id,
+            mask: self.mask,
+            data: offset as _,
+        }
+    }
+}
+
+/// An amba driver.
+pub trait Driver {
+    /// Data stored on device by driver.
+    type Data: PointerWrapper + Send + Sync + driver::DeviceRemoval = ();
+
+    /// The type that implements the power-management operations.
+    ///
+    /// The default is a type that implements no power-management operations. Drivers that do
+    /// implement them need to specify the type (commonly [`Self`]).
+    type PowerOps: power::Operations<Data = Self::Data> = power::NoOperations<Self::Data>;
+
+    /// The type holding information about each device id supported by the driver.
+    type IdInfo: 'static = ();
+
+    /// The table of device ids supported by the driver.
+    const ID_TABLE: Option<driver::IdTable<'static, DeviceId, Self::IdInfo>> = None;
+
+    /// Probes for the device with the given id.
+    fn probe(dev: &mut Device, id_info: Option<&Self::IdInfo>) -> Result<Self::Data>;
+
+    /// Cleans any resources up that are associated with the device.
+    ///
+    /// This is called when the driver is detached from the device.
+    fn remove(_data: &Self::Data) {}
+}
+
+/// An adapter for the registration of Amba drivers.
+pub struct Adapter<T: Driver>(T);
+
+impl<T: Driver> driver::DriverOps for Adapter<T> {
+    type RegType = bindings::amba_driver;
+
+    unsafe fn register(
+        reg: *mut bindings::amba_driver,
+        name: &'static CStr,
+        module: &'static ThisModule,
+    ) -> Result {
+        // SAFETY: By the safety requirements of this function (defined in the trait definition),
+        // `reg` is non-null and valid.
+        let amba = unsafe { &mut *reg };
+        amba.drv.name = name.as_char_ptr();
+        amba.drv.owner = module.0;
+        amba.probe = Some(probe_callback::<T>);
+        amba.remove = Some(remove_callback::<T>);
+        if let Some(t) = T::ID_TABLE {
+            amba.id_table = t.as_ref();
+        }
+        if cfg!(CONFIG_PM) {
+            // SAFETY: `probe_callback` sets the driver data after calling `T::Data::into_pointer`,
+            // and we guarantee that `T::Data` is the same as `T::PowerOps::Data` by a constraint
+            // in the type declaration.
+            amba.drv.pm = unsafe { power::OpsTable::<T::PowerOps>::build() };
+        }
+        // SAFETY: By the safety requirements of this function, `reg` is valid and fully
+        // initialised.
+        to_result(unsafe { bindings::amba_driver_register(reg) })
+    }
+
+    unsafe fn unregister(reg: *mut bindings::amba_driver) {
+        // SAFETY: By the safety requirements of this function (defined in the trait definition),
+        // `reg` was passed (and updated) by a previous successful call to `amba_driver_register`.
+        unsafe { bindings::amba_driver_unregister(reg) };
+    }
+}
+
+unsafe extern "C" fn probe_callback<T: Driver>(
+    adev: *mut bindings::amba_device,
+    aid: *const bindings::amba_id,
+) -> core::ffi::c_int {
+    from_kernel_result! {
+        // SAFETY: `adev` is valid by the contract with the C code. `dev` is alive only for the
+        // duration of this call, so it is guaranteed to remain alive for the lifetime of `dev`.
+        let mut dev = unsafe { Device::from_ptr(adev) };
+        // SAFETY: `aid` is valid by the requirements the contract with the C code.
+        let offset = unsafe { (*aid).data };
+        let info = if offset.is_null() {
+            None
+        } else {
+            // SAFETY: The offset comes from a previous call to `offset_from` in `IdArray::new`,
+            // which guarantees that the resulting pointer is within the table.
+            let ptr = unsafe {
+                aid.cast::<u8>()
+                    .offset(offset as _)
+                    .cast::<Option<T::IdInfo>>()
+            };
+            // SAFETY: The id table has a static lifetime, so `ptr` is guaranteed to be valid for
+            // read.
+            unsafe { (&*ptr).as_ref() }
+        };
+        let data = T::probe(&mut dev, info)?;
+        let ptr = T::Data::into_pointer(data);
+        // SAFETY: `adev` is valid for write by the contract with the C code.
+        unsafe { bindings::amba_set_drvdata(adev, ptr as _) };
+        Ok(0)
+    }
+}
+
+unsafe extern "C" fn remove_callback<T: Driver>(adev: *mut bindings::amba_device) {
+    // SAFETY: `adev` is valid by the contract with the C code.
+    let ptr = unsafe { bindings::amba_get_drvdata(adev) };
+    // SAFETY: The value returned by `amba_get_drvdata` was stored by a previous call to
+    // `amba_set_drvdata` in `probe_callback` above; the value comes from a call to
+    // `T::Data::into_pointer`.
+    let data = unsafe { T::Data::from_pointer(ptr) };
+    T::remove(&data);
+    <T::Data as driver::DeviceRemoval>::device_remove(&data);
+}
+
+/// An Amba device.
+///
+/// # Invariants
+///
+/// The field `ptr` is non-null and valid for the lifetime of the object.
+pub struct Device {
+    ptr: *mut bindings::amba_device,
+    res: Option<Resource>,
+}
+
+impl Device {
+    /// Creates a new device from the given pointer.
+    ///
+    /// # Safety
+    ///
+    /// `ptr` must be non-null and valid. It must remain valid for the lifetime of the returned
+    /// instance.
+    unsafe fn from_ptr(ptr: *mut bindings::amba_device) -> Self {
+        // SAFETY: The safety requirements of the function ensure that `ptr` is valid.
+        let dev = unsafe { &mut *ptr };
+        // INVARIANT: The safety requirements of the function ensure the lifetime invariant.
+        Self {
+            ptr,
+            res: Resource::new(dev.res.start, dev.res.end),
+        }
+    }
+
+    /// Returns the io mem resource associated with the device, if there is one.
+    ///
+    /// Ownership of the resource is transferred to the caller, so subsequent calls to this
+    /// function will return [`None`].
+    pub fn take_resource(&mut self) -> Option<Resource> {
+        self.res.take()
+    }
+
+    /// Returns the index-th irq associated with the device, if one exists.
+    pub fn irq(&self, index: usize) -> Option<u32> {
+        // SAFETY: By the type invariants, `self.ptr` is valid for read.
+        let dev = unsafe { &*self.ptr };
+        if index >= dev.irq.len() || dev.irq[index] == 0 {
+            None
+        } else {
+            Some(dev.irq[index])
+        }
+    }
+}
+
+// SAFETY: The device returned by `raw_device` is the raw Amba device.
+unsafe impl device::RawDevice for Device {
+    fn raw_device(&self) -> *mut bindings::device {
+        // SAFETY: By the type invariants, we know that `self.ptr` is non-null and valid.
+        unsafe { &mut (*self.ptr).dev }
+    }
+}
+
+/// Declares a kernel module that exposes a single amba driver.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::{amba, define_amba_id_table, module_amba_driver};
+/// #
+/// struct MyDriver;
+/// impl amba::Driver for MyDriver {
+///     // [...]
+/// #   fn probe(_dev: &mut amba::Device, _id: Option<&Self::IdInfo>) -> Result {
+/// #       Ok(())
+/// #   }
+/// #   define_amba_id_table! {(), [
+/// #       ({ id: 0x00041061, mask: 0x000fffff }, None),
+/// #   ]}
+/// }
+///
+/// module_amba_driver! {
+///     type: MyDriver,
+///     name: b"module_name",
+///     author: b"Author name",
+///     license: b"GPL",
+/// }
+/// ```
+#[macro_export]
+macro_rules! module_amba_driver {
+    ($($f:tt)*) => {
+        $crate::module_driver!(<T>, $crate::amba::Adapter<T>, { $($f)* });
+    };
+}
+
+/// Defines the id table for amba devices.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::{amba, define_amba_id_table};
+/// #
+/// # struct Sample;
+/// # impl kernel::amba::Driver for Sample {
+/// #   fn probe(_dev: &mut amba::Device, _id: Option<&Self::IdInfo>) -> Result {
+/// #       Ok(())
+/// #   }
+/// define_amba_id_table! {(), [
+///     ({ id: 0x00041061, mask: 0x000fffff }, None),
+/// ]}
+/// # }
+/// ```
+#[macro_export]
+macro_rules! define_amba_id_table {
+    ($data_type:ty, $($t:tt)*) => {
+        type IdInfo = $data_type;
+        $crate::define_id_table!(ID_TABLE, $crate::amba::DeviceId, $data_type, $($t)*);
+    };
+}
diff --git a/rust/kernel/build_assert.rs b/rust/kernel/build_assert.rs
new file mode 100644
index 000000000000..72c533d8058d
--- /dev/null
+++ b/rust/kernel/build_assert.rs
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Build-time assert.
+
+/// Fails the build if the code path calling `build_error!` can possibly be executed.
+///
+/// If the macro is executed in const context, `build_error!` will panic.
+/// If the compiler or optimizer cannot guarantee that `build_error!` can never
+/// be called, a build error will be triggered.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::build_error;
+/// #[inline]
+/// fn foo(a: usize) -> usize {
+///     a.checked_add(1).unwrap_or_else(|| build_error!("overflow"))
+/// }
+///
+/// assert_eq!(foo(usize::MAX - 1), usize::MAX); // OK.
+/// // foo(usize::MAX); // Fails to compile.
+/// ```
+#[macro_export]
+macro_rules! build_error {
+    () => {{
+        $crate::build_error("")
+    }};
+    ($msg:expr) => {{
+        $crate::build_error($msg)
+    }};
+}
+
+/// Asserts that a boolean expression is `true` at compile time.
+///
+/// If the condition is evaluated to `false` in const context, `build_assert!`
+/// will panic. If the compiler or optimizer cannot guarantee the condition will
+/// be evaluated to `true`, a build error will be triggered.
+///
+/// [`static_assert!`] should be preferred to `build_assert!` whenever possible.
+///
+/// # Examples
+///
+/// These examples show that different types of [`assert!`] will trigger errors
+/// at different stage of compilation. It is preferred to err as early as
+/// possible, so [`static_assert!`] should be used whenever possible.
+// TODO: Could be `compile_fail` when supported.
+/// ```ignore
+/// fn foo() {
+///     static_assert!(1 > 1); // Compile-time error
+///     build_assert!(1 > 1); // Build-time error
+///     assert!(1 > 1); // Run-time error
+/// }
+/// ```
+///
+/// When the condition refers to generic parameters or parameters of an inline function,
+/// [`static_assert!`] cannot be used. Use `build_assert!` in this scenario.
+/// ```
+/// fn foo<const N: usize>() {
+///     // `static_assert!(N > 1);` is not allowed
+///     build_assert!(N > 1); // Build-time check
+///     assert!(N > 1); // Run-time check
+/// }
+///
+/// #[inline]
+/// fn bar(n: usize) {
+///     // `static_assert!(n > 1);` is not allowed
+///     build_assert!(n > 1); // Build-time check
+///     assert!(n > 1); // Run-time check
+/// }
+/// ```
+#[macro_export]
+macro_rules! build_assert {
+    ($cond:expr $(,)?) => {{
+        if !$cond {
+            $crate::build_error(concat!("assertion failed: ", stringify!($cond)));
+        }
+    }};
+    ($cond:expr, $msg:expr) => {{
+        if !$cond {
+            $crate::build_error($msg);
+        }
+    }};
+}
diff --git a/rust/kernel/chrdev.rs b/rust/kernel/chrdev.rs
new file mode 100644
index 000000000000..5b1e083c23b9
--- /dev/null
+++ b/rust/kernel/chrdev.rs
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Character devices.
+//!
+//! Also called "char devices", `chrdev`, `cdev`.
+//!
+//! C header: [`include/linux/cdev.h`](../../../../include/linux/cdev.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/core-api/kernel-api.html#char-devices>
+
+use alloc::boxed::Box;
+use core::convert::TryInto;
+use core::marker::PhantomPinned;
+use core::pin::Pin;
+
+use crate::bindings;
+use crate::error::{code::*, Error, Result};
+use crate::file;
+use crate::str::CStr;
+
+/// Character device.
+///
+/// # Invariants
+///
+///   - [`self.0`] is valid and non-null.
+///   - [`(*self.0).ops`] is valid, non-null and has static lifetime.
+///   - [`(*self.0).owner`] is valid and, if non-null, has module lifetime.
+struct Cdev(*mut bindings::cdev);
+
+impl Cdev {
+    fn alloc(
+        fops: &'static bindings::file_operations,
+        module: &'static crate::ThisModule,
+    ) -> Result<Self> {
+        // SAFETY: FFI call.
+        let cdev = unsafe { bindings::cdev_alloc() };
+        if cdev.is_null() {
+            return Err(ENOMEM);
+        }
+        // SAFETY: `cdev` is valid and non-null since `cdev_alloc()`
+        // returned a valid pointer which was null-checked.
+        unsafe {
+            (*cdev).ops = fops;
+            (*cdev).owner = module.0;
+        }
+        // INVARIANTS:
+        //   - [`self.0`] is valid and non-null.
+        //   - [`(*self.0).ops`] is valid, non-null and has static lifetime,
+        //     because it was coerced from a reference with static lifetime.
+        //   - [`(*self.0).owner`] is valid and, if non-null, has module lifetime,
+        //     guaranteed by the [`ThisModule`] invariant.
+        Ok(Self(cdev))
+    }
+
+    fn add(&mut self, dev: bindings::dev_t, count: core::ffi::c_uint) -> Result {
+        // SAFETY: According to the type invariants:
+        //   - [`self.0`] can be safely passed to [`bindings::cdev_add`].
+        //   - [`(*self.0).ops`] will live at least as long as [`self.0`].
+        //   - [`(*self.0).owner`] will live at least as long as the
+        //     module, which is an implicit requirement.
+        let rc = unsafe { bindings::cdev_add(self.0, dev, count) };
+        if rc != 0 {
+            return Err(Error::from_kernel_errno(rc));
+        }
+        Ok(())
+    }
+}
+
+impl Drop for Cdev {
+    fn drop(&mut self) {
+        // SAFETY: [`self.0`] is valid and non-null by the type invariants.
+        unsafe {
+            bindings::cdev_del(self.0);
+        }
+    }
+}
+
+struct RegistrationInner<const N: usize> {
+    dev: bindings::dev_t,
+    used: usize,
+    cdevs: [Option<Cdev>; N],
+    _pin: PhantomPinned,
+}
+
+/// Character device registration.
+///
+/// May contain up to a fixed number (`N`) of devices. Must be pinned.
+pub struct Registration<const N: usize> {
+    name: &'static CStr,
+    minors_start: u16,
+    this_module: &'static crate::ThisModule,
+    inner: Option<RegistrationInner<N>>,
+}
+
+impl<const N: usize> Registration<{ N }> {
+    /// Creates a [`Registration`] object for a character device.
+    ///
+    /// This does *not* register the device: see [`Self::register()`].
+    ///
+    /// This associated function is intended to be used when you need to avoid
+    /// a memory allocation, e.g. when the [`Registration`] is a member of
+    /// a bigger structure inside your [`crate::Module`] instance. If you
+    /// are going to pin the registration right away, call
+    /// [`Self::new_pinned()`] instead.
+    pub fn new(
+        name: &'static CStr,
+        minors_start: u16,
+        this_module: &'static crate::ThisModule,
+    ) -> Self {
+        Registration {
+            name,
+            minors_start,
+            this_module,
+            inner: None,
+        }
+    }
+
+    /// Creates a pinned [`Registration`] object for a character device.
+    ///
+    /// This does *not* register the device: see [`Self::register()`].
+    pub fn new_pinned(
+        name: &'static CStr,
+        minors_start: u16,
+        this_module: &'static crate::ThisModule,
+    ) -> Result<Pin<Box<Self>>> {
+        Ok(Pin::from(Box::try_new(Self::new(
+            name,
+            minors_start,
+            this_module,
+        ))?))
+    }
+
+    /// Registers a character device.
+    ///
+    /// You may call this once per device type, up to `N` times.
+    pub fn register<T: file::Operations<OpenData = ()>>(self: Pin<&mut Self>) -> Result {
+        // SAFETY: We must ensure that we never move out of `this`.
+        let this = unsafe { self.get_unchecked_mut() };
+        if this.inner.is_none() {
+            let mut dev: bindings::dev_t = 0;
+            // SAFETY: Calling unsafe function. `this.name` has `'static`
+            // lifetime.
+            let res = unsafe {
+                bindings::alloc_chrdev_region(
+                    &mut dev,
+                    this.minors_start.into(),
+                    N.try_into()?,
+                    this.name.as_char_ptr(),
+                )
+            };
+            if res != 0 {
+                return Err(Error::from_kernel_errno(res));
+            }
+            const NONE: Option<Cdev> = None;
+            this.inner = Some(RegistrationInner {
+                dev,
+                used: 0,
+                cdevs: [NONE; N],
+                _pin: PhantomPinned,
+            });
+        }
+
+        let mut inner = this.inner.as_mut().unwrap();
+        if inner.used == N {
+            return Err(EINVAL);
+        }
+
+        // SAFETY: The adapter doesn't retrieve any state yet, so it's compatible with any
+        // registration.
+        let fops = unsafe { file::OperationsVtable::<Self, T>::build() };
+        let mut cdev = Cdev::alloc(fops, this.this_module)?;
+        cdev.add(inner.dev + inner.used as bindings::dev_t, 1)?;
+        inner.cdevs[inner.used].replace(cdev);
+        inner.used += 1;
+        Ok(())
+    }
+}
+
+impl<const N: usize> file::OpenAdapter<()> for Registration<{ N }> {
+    unsafe fn convert(_inode: *mut bindings::inode, _file: *mut bindings::file) -> *const () {
+        // TODO: Update the SAFETY comment on the call to `FileOperationsVTable::build` above once
+        // this is updated to retrieve state.
+        &()
+    }
+}
+
+// SAFETY: `Registration` does not expose any of its state across threads
+// (it is fine for multiple threads to have a shared reference to it).
+unsafe impl<const N: usize> Sync for Registration<{ N }> {}
+
+impl<const N: usize> Drop for Registration<{ N }> {
+    fn drop(&mut self) {
+        if let Some(inner) = self.inner.as_mut() {
+            // Replicate kernel C behaviour: drop [`Cdev`]s before calling
+            // [`bindings::unregister_chrdev_region`].
+            for i in 0..inner.used {
+                inner.cdevs[i].take();
+            }
+            // SAFETY: [`self.inner`] is Some, so [`inner.dev`] was previously
+            // created using [`bindings::alloc_chrdev_region`].
+            unsafe {
+                bindings::unregister_chrdev_region(inner.dev, N.try_into().unwrap());
+            }
+        }
+    }
+}
diff --git a/rust/kernel/clk.rs b/rust/kernel/clk.rs
new file mode 100644
index 000000000000..1ec478d96abc
--- /dev/null
+++ b/rust/kernel/clk.rs
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Common clock framework.
+//!
+//! C header: [`include/linux/clk.h`](../../../../include/linux/clk.h)
+
+use crate::{bindings, error::Result, to_result};
+use core::mem::ManuallyDrop;
+
+/// Represents `struct clk *`.
+///
+/// # Invariants
+///
+/// The pointer is valid.
+pub struct Clk(*mut bindings::clk);
+
+impl Clk {
+    /// Creates new clock structure from a raw pointer.
+    ///
+    /// # Safety
+    ///
+    /// The pointer must be valid.
+    pub unsafe fn new(clk: *mut bindings::clk) -> Self {
+        Self(clk)
+    }
+
+    /// Returns value of the rate field of `struct clk`.
+    pub fn get_rate(&self) -> usize {
+        // SAFETY: The pointer is valid by the type invariant.
+        unsafe { bindings::clk_get_rate(self.0) as usize }
+    }
+
+    /// Prepares and enables the underlying hardware clock.
+    ///
+    /// This function should not be called in atomic context.
+    pub fn prepare_enable(self) -> Result<EnabledClk> {
+        // SAFETY: The pointer is valid by the type invariant.
+        to_result(unsafe { bindings::clk_prepare_enable(self.0) })?;
+        Ok(EnabledClk(self))
+    }
+}
+
+impl Drop for Clk {
+    fn drop(&mut self) {
+        // SAFETY: The pointer is valid by the type invariant.
+        unsafe { bindings::clk_put(self.0) };
+    }
+}
+
+// SAFETY: `Clk` is not restricted to a single thread so it is safe
+// to move it between threads.
+unsafe impl Send for Clk {}
+
+/// A clock variant that is prepared and enabled.
+pub struct EnabledClk(Clk);
+
+impl EnabledClk {
+    /// Returns value of the rate field of `struct clk`.
+    pub fn get_rate(&self) -> usize {
+        self.0.get_rate()
+    }
+
+    /// Disables and later unprepares the underlying hardware clock prematurely.
+    ///
+    /// This function should not be called in atomic context.
+    pub fn disable_unprepare(self) -> Clk {
+        let mut clk = ManuallyDrop::new(self);
+        // SAFETY: The pointer is valid by the type invariant.
+        unsafe { bindings::clk_disable_unprepare(clk.0 .0) };
+        core::mem::replace(&mut clk.0, Clk(core::ptr::null_mut()))
+    }
+}
+
+impl Drop for EnabledClk {
+    fn drop(&mut self) {
+        // SAFETY: The pointer is valid by the type invariant.
+        unsafe { bindings::clk_disable_unprepare(self.0 .0) };
+    }
+}
diff --git a/rust/kernel/cred.rs b/rust/kernel/cred.rs
new file mode 100644
index 000000000000..beacc71d92ac
--- /dev/null
+++ b/rust/kernel/cred.rs
@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Credentials management.
+//!
+//! C header: [`include/linux/cred.h`](../../../../include/linux/cred.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/security/credentials.html>
+
+use crate::{bindings, AlwaysRefCounted};
+use core::cell::UnsafeCell;
+
+/// Wraps the kernel's `struct cred`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `get_cred` ensures that the
+/// allocation remains valid at least until the matching call to `put_cred`.
+#[repr(transparent)]
+pub struct Credential(pub(crate) UnsafeCell<bindings::cred>);
+
+impl Credential {
+    /// Creates a reference to a [`Credential`] from a valid pointer.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
+    /// returned [`Credential`] reference.
+    pub(crate) unsafe fn from_ptr<'a>(ptr: *const bindings::cred) -> &'a Self {
+        // SAFETY: The safety requirements guarantee the validity of the dereference, while the
+        // `Credential` type being transparent makes the cast ok.
+        unsafe { &*ptr.cast() }
+    }
+}
+
+// SAFETY: The type invariants guarantee that `Credential` is always ref-counted.
+unsafe impl AlwaysRefCounted for Credential {
+    fn inc_ref(&self) {
+        // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+        unsafe { bindings::get_cred(self.0.get()) };
+    }
+
+    unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
+        // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+        unsafe { bindings::put_cred(obj.cast().as_ptr()) };
+    }
+}
diff --git a/rust/kernel/delay.rs b/rust/kernel/delay.rs
new file mode 100644
index 000000000000..1e987fa65941
--- /dev/null
+++ b/rust/kernel/delay.rs
@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Delay functions for operations like sleeping.
+//!
+//! C header: [`include/linux/delay.h`](../../../../include/linux/delay.h)
+
+use crate::bindings;
+use core::{cmp::min, time::Duration};
+
+const MILLIS_PER_SEC: u64 = 1_000;
+
+fn coarse_sleep_conversion(duration: Duration) -> core::ffi::c_uint {
+    let milli_as_nanos = Duration::MILLISECOND.subsec_nanos();
+
+    // Rounds the nanosecond component of `duration` up to the nearest millisecond.
+    let nanos_as_millis = duration.subsec_nanos().wrapping_add(milli_as_nanos - 1) / milli_as_nanos;
+
+    // Saturates the second component of `duration` to `c_uint::MAX`.
+    let seconds_as_millis = min(
+        duration.as_secs().saturating_mul(MILLIS_PER_SEC),
+        u64::from(core::ffi::c_uint::MAX),
+    ) as core::ffi::c_uint;
+
+    seconds_as_millis.saturating_add(nanos_as_millis)
+}
+
+/// Sleeps safely even with waitqueue interruptions.
+///
+/// This function forwards the call to the C side `msleep` function. As a result,
+/// `duration` will be rounded up to the nearest millisecond if granularity less
+/// than a millisecond is provided. Any [`Duration`] that exceeds
+/// [`c_uint::MAX`][core::ffi::c_uint::MAX] in milliseconds is saturated.
+///
+/// # Examples
+///
+// Keep these in sync with `test_coarse_sleep_examples`.
+/// ```
+/// # use core::time::Duration;
+/// # use kernel::delay::coarse_sleep;
+/// coarse_sleep(Duration::ZERO);                   // Equivalent to `msleep(0)`.
+/// coarse_sleep(Duration::from_nanos(1));          // Equivalent to `msleep(1)`.
+///
+/// coarse_sleep(Duration::from_nanos(1_000_000));  // Equivalent to `msleep(1)`.
+/// coarse_sleep(Duration::from_nanos(1_000_001));  // Equivalent to `msleep(2)`.
+/// coarse_sleep(Duration::from_nanos(1_999_999));  // Equivalent to `msleep(2)`.
+///
+/// coarse_sleep(Duration::from_millis(1));         // Equivalent to `msleep(1)`.
+/// coarse_sleep(Duration::from_millis(2));         // Equivalent to `msleep(2)`.
+///
+/// coarse_sleep(Duration::from_secs(1));           // Equivalent to `msleep(1000)`.
+/// coarse_sleep(Duration::new(1, 1));              // Equivalent to `msleep(1001)`.
+/// coarse_sleep(Duration::new(1, 2));              // Equivalent to `msleep(1001)`.
+/// ```
+pub fn coarse_sleep(duration: Duration) {
+    // SAFETY: `msleep` is safe for all values of its argument.
+    unsafe { bindings::msleep(coarse_sleep_conversion(duration)) }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{coarse_sleep_conversion, MILLIS_PER_SEC};
+    use core::time::Duration;
+
+    #[test]
+    fn test_coarse_sleep_examples() {
+        // Keep these in sync with `coarse_sleep`'s `# Examples` section.
+
+        assert_eq!(coarse_sleep_conversion(Duration::ZERO), 0);
+        assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1)), 1);
+
+        assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1_000_000)), 1);
+        assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1_000_001)), 2);
+        assert_eq!(coarse_sleep_conversion(Duration::from_nanos(1_999_999)), 2);
+
+        assert_eq!(coarse_sleep_conversion(Duration::from_millis(1)), 1);
+        assert_eq!(coarse_sleep_conversion(Duration::from_millis(2)), 2);
+
+        assert_eq!(coarse_sleep_conversion(Duration::from_secs(1)), 1000);
+        assert_eq!(coarse_sleep_conversion(Duration::new(1, 1)), 1001);
+        assert_eq!(coarse_sleep_conversion(Duration::new(1, 2)), 1001);
+    }
+
+    #[test]
+    fn test_coarse_sleep_saturation() {
+        assert!(
+            coarse_sleep_conversion(Duration::new(
+                core::ffi::c_uint::MAX as u64 / MILLIS_PER_SEC,
+                0
+            )) < core::ffi::c_uint::MAX
+        );
+        assert_eq!(
+            coarse_sleep_conversion(Duration::new(
+                core::ffi::c_uint::MAX as u64 / MILLIS_PER_SEC,
+                999_999_999
+            )),
+            core::ffi::c_uint::MAX
+        );
+
+        assert_eq!(
+            coarse_sleep_conversion(Duration::MAX),
+            core::ffi::c_uint::MAX
+        );
+    }
+}
diff --git a/rust/kernel/device.rs b/rust/kernel/device.rs
new file mode 100644
index 000000000000..c37f555c534d
--- /dev/null
+++ b/rust/kernel/device.rs
@@ -0,0 +1,527 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Generic devices that are part of the kernel's driver model.
+//!
+//! C header: [`include/linux/device.h`](../../../../include/linux/device.h)
+
+#[cfg(CONFIG_COMMON_CLK)]
+use crate::{clk::Clk, error::from_kernel_err_ptr};
+
+use crate::{
+    bindings,
+    revocable::{Revocable, RevocableGuard},
+    str::CStr,
+    sync::{LockClassKey, NeedsLockClass, RevocableMutex, RevocableMutexGuard, UniqueRef},
+    Result,
+};
+use core::{
+    fmt,
+    ops::{Deref, DerefMut},
+    pin::Pin,
+};
+
+#[cfg(CONFIG_PRINTK)]
+use crate::c_str;
+
+/// A raw device.
+///
+/// # Safety
+///
+/// Implementers must ensure that the `*mut device` returned by [`RawDevice::raw_device`] is
+/// related to `self`, that is, actions on it will affect `self`. For example, if one calls
+/// `get_device`, then the refcount on the device represented by `self` will be incremented.
+///
+/// Additionally, implementers must ensure that the device is never renamed. Commit a5462516aa99
+/// ("driver-core: document restrictions on device_rename()") has details on why `device_rename`
+/// should not be used.
+pub unsafe trait RawDevice {
+    /// Returns the raw `struct device` related to `self`.
+    fn raw_device(&self) -> *mut bindings::device;
+
+    /// Returns the name of the device.
+    fn name(&self) -> &CStr {
+        let ptr = self.raw_device();
+
+        // SAFETY: `ptr` is valid because `self` keeps it alive.
+        let name = unsafe { bindings::dev_name(ptr) };
+
+        // SAFETY: The name of the device remains valid while it is alive (because the device is
+        // never renamed, per the safety requirement of this trait). This is guaranteed to be the
+        // case because the reference to `self` outlives the one of the returned `CStr` (enforced
+        // by the compiler because of their lifetimes).
+        unsafe { CStr::from_char_ptr(name) }
+    }
+
+    /// Lookups a clock producer consumed by this device.
+    ///
+    /// Returns a managed reference to the clock producer.
+    #[cfg(CONFIG_COMMON_CLK)]
+    fn clk_get(&self, id: Option<&CStr>) -> Result<Clk> {
+        let id_ptr = match id {
+            Some(cstr) => cstr.as_char_ptr(),
+            None => core::ptr::null(),
+        };
+
+        // SAFETY: `id_ptr` is optional and may be either a valid pointer
+        // from the type invariant or NULL otherwise.
+        let clk_ptr = unsafe { from_kernel_err_ptr(bindings::clk_get(self.raw_device(), id_ptr)) }?;
+
+        // SAFETY: Clock is initialized with valid pointer returned from `bindings::clk_get` call.
+        unsafe { Ok(Clk::new(clk_ptr)) }
+    }
+
+    /// Prints an emergency-level message (level 0) prefixed with device information.
+    ///
+    /// More details are available from [`dev_emerg`].
+    fn pr_emerg(&self, args: fmt::Arguments<'_>) {
+        // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+        unsafe { self.printk(bindings::KERN_EMERG, args) };
+    }
+
+    /// Prints an alert-level message (level 1) prefixed with device information.
+    ///
+    /// More details are available from [`dev_alert`].
+    fn pr_alert(&self, args: fmt::Arguments<'_>) {
+        // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+        unsafe { self.printk(bindings::KERN_ALERT, args) };
+    }
+
+    /// Prints a critical-level message (level 2) prefixed with device information.
+    ///
+    /// More details are available from [`dev_crit`].
+    fn pr_crit(&self, args: fmt::Arguments<'_>) {
+        // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+        unsafe { self.printk(bindings::KERN_CRIT, args) };
+    }
+
+    /// Prints an error-level message (level 3) prefixed with device information.
+    ///
+    /// More details are available from [`dev_err`].
+    fn pr_err(&self, args: fmt::Arguments<'_>) {
+        // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+        unsafe { self.printk(bindings::KERN_ERR, args) };
+    }
+
+    /// Prints a warning-level message (level 4) prefixed with device information.
+    ///
+    /// More details are available from [`dev_warn`].
+    fn pr_warn(&self, args: fmt::Arguments<'_>) {
+        // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+        unsafe { self.printk(bindings::KERN_WARNING, args) };
+    }
+
+    /// Prints a notice-level message (level 5) prefixed with device information.
+    ///
+    /// More details are available from [`dev_notice`].
+    fn pr_notice(&self, args: fmt::Arguments<'_>) {
+        // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+        unsafe { self.printk(bindings::KERN_NOTICE, args) };
+    }
+
+    /// Prints an info-level message (level 6) prefixed with device information.
+    ///
+    /// More details are available from [`dev_info`].
+    fn pr_info(&self, args: fmt::Arguments<'_>) {
+        // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+        unsafe { self.printk(bindings::KERN_INFO, args) };
+    }
+
+    /// Prints a debug-level message (level 7) prefixed with device information.
+    ///
+    /// More details are available from [`dev_dbg`].
+    fn pr_dbg(&self, args: fmt::Arguments<'_>) {
+        if cfg!(debug_assertions) {
+            // SAFETY: `klevel` is null-terminated, uses one of the kernel constants.
+            unsafe { self.printk(bindings::KERN_DEBUG, args) };
+        }
+    }
+
+    /// Prints the provided message to the console.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `klevel` is null-terminated; in particular, one of the
+    /// `KERN_*`constants, for example, `KERN_CRIT`, `KERN_ALERT`, etc.
+    #[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))]
+    unsafe fn printk(&self, klevel: &[u8], msg: fmt::Arguments<'_>) {
+        // SAFETY: `klevel` is null-terminated and one of the kernel constants. `self.raw_device`
+        // is valid because `self` is valid. The "%pA" format string expects a pointer to
+        // `fmt::Arguments`, which is what we're passing as the last argument.
+        #[cfg(CONFIG_PRINTK)]
+        unsafe {
+            bindings::_dev_printk(
+                klevel as *const _ as *const core::ffi::c_char,
+                self.raw_device(),
+                c_str!("%pA").as_char_ptr(),
+                &msg as *const _ as *const core::ffi::c_void,
+            )
+        };
+    }
+}
+
+/// A ref-counted device.
+///
+/// # Invariants
+///
+/// `ptr` is valid, non-null, and has a non-zero reference count. One of the references is owned by
+/// `self`, and will be decremented when `self` is dropped.
+pub struct Device {
+    pub(crate) ptr: *mut bindings::device,
+}
+
+// SAFETY: `Device` only holds a pointer to a C device, which is safe to be used from any thread.
+unsafe impl Send for Device {}
+
+// SAFETY: `Device` only holds a pointer to a C device, references to which are safe to be used
+// from any thread.
+unsafe impl Sync for Device {}
+
+impl Device {
+    /// Creates a new device instance.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `ptr` is valid, non-null, and has a non-zero reference count.
+    pub unsafe fn new(ptr: *mut bindings::device) -> Self {
+        // SAFETY: By the safety requirements, ptr is valid and its refcounted will be incremented.
+        unsafe { bindings::get_device(ptr) };
+        // INVARIANT: The safety requirements satisfy all but one invariant, which is that `self`
+        // owns a reference. This is satisfied by the call to `get_device` above.
+        Self { ptr }
+    }
+
+    /// Creates a new device instance from an existing [`RawDevice`] instance.
+    pub fn from_dev(dev: &dyn RawDevice) -> Self {
+        // SAFETY: The requirements are satisfied by the existence of `RawDevice` and its safety
+        // requirements.
+        unsafe { Self::new(dev.raw_device()) }
+    }
+}
+
+// SAFETY: The device returned by `raw_device` is the one for which we hold a reference.
+unsafe impl RawDevice for Device {
+    fn raw_device(&self) -> *mut bindings::device {
+        self.ptr
+    }
+}
+
+impl Drop for Device {
+    fn drop(&mut self) {
+        // SAFETY: By the type invariants, we know that `self` owns a reference, so it is safe to
+        // relinquish it now.
+        unsafe { bindings::put_device(self.ptr) };
+    }
+}
+
+/// Device data.
+///
+/// When a device is removed (for whatever reason, for example, because the device was unplugged or
+/// because the user decided to unbind the driver), the driver is given a chance to clean its state
+/// up, and all io resources should ideally not be used anymore.
+///
+/// However, the device data is reference-counted because other subsystems hold pointers to it. So
+/// some device state must be freed and not used anymore, while others must remain accessible.
+///
+/// This struct separates the device data into three categories:
+///   1. Registrations: are destroyed when the device is removed, but before the io resources
+///      become inaccessible.
+///   2. Io resources: are available until the device is removed.
+///   3. General data: remain available as long as the ref count is nonzero.
+///
+/// This struct implements the `DeviceRemoval` trait so that it can clean resources up even if not
+/// explicitly called by the device drivers.
+pub struct Data<T, U, V> {
+    registrations: RevocableMutex<T>,
+    resources: Revocable<U>,
+    general: V,
+}
+
+/// Safely creates an new reference-counted instance of [`Data`].
+#[doc(hidden)]
+#[macro_export]
+macro_rules! new_device_data {
+    ($reg:expr, $res:expr, $gen:expr, $name:literal) => {{
+        static CLASS1: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        static CLASS2: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        let regs = $reg;
+        let res = $res;
+        let gen = $gen;
+        let name = $crate::c_str!($name);
+        $crate::device::Data::try_new(regs, res, gen, name, &CLASS1, &CLASS2)
+    }};
+}
+
+impl<T, U, V> Data<T, U, V> {
+    /// Creates a new instance of `Data`.
+    ///
+    /// It is recommended that the [`new_device_data`] macro be used as it automatically creates
+    /// the lock classes.
+    pub fn try_new(
+        registrations: T,
+        resources: U,
+        general: V,
+        name: &'static CStr,
+        key1: &'static LockClassKey,
+        key2: &'static LockClassKey,
+    ) -> Result<Pin<UniqueRef<Self>>> {
+        let mut ret = Pin::from(UniqueRef::try_new(Self {
+            // SAFETY: We call `RevocableMutex::init` below.
+            registrations: unsafe { RevocableMutex::new(registrations) },
+            resources: Revocable::new(resources),
+            general,
+        })?);
+
+        // SAFETY: `Data::registrations` is pinned when `Data` is.
+        let pinned = unsafe { ret.as_mut().map_unchecked_mut(|d| &mut d.registrations) };
+        pinned.init(name, key1, key2);
+        Ok(ret)
+    }
+
+    /// Returns the resources if they're still available.
+    pub fn resources(&self) -> Option<RevocableGuard<'_, U>> {
+        self.resources.try_access()
+    }
+
+    /// Returns the locked registrations if they're still available.
+    pub fn registrations(&self) -> Option<RevocableMutexGuard<'_, T>> {
+        self.registrations.try_write()
+    }
+}
+
+impl<T, U, V> crate::driver::DeviceRemoval for Data<T, U, V> {
+    fn device_remove(&self) {
+        // We revoke the registrations first so that resources are still available to them during
+        // unregistration.
+        self.registrations.revoke();
+
+        // Release resources now. General data remains available.
+        self.resources.revoke();
+    }
+}
+
+impl<T, U, V> Deref for Data<T, U, V> {
+    type Target = V;
+
+    fn deref(&self) -> &V {
+        &self.general
+    }
+}
+
+impl<T, U, V> DerefMut for Data<T, U, V> {
+    fn deref_mut(&mut self) -> &mut V {
+        &mut self.general
+    }
+}
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! dev_printk {
+    ($method:ident, $dev:expr, $($f:tt)*) => {
+        {
+            // We have an explicity `use` statement here so that callers of this macro are not
+            // required to explicitly use the `RawDevice` trait to use its functions.
+            use $crate::device::RawDevice;
+            ($dev).$method(core::format_args!($($f)*));
+        }
+    }
+}
+
+/// Prints an emergency-level message (level 0) prefixed with device information.
+///
+/// This level should be used if the system is unusable.
+///
+/// Equivalent to the kernel's `dev_emerg` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+///     dev_emerg!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_emerg {
+    ($($f:tt)*) => { $crate::dev_printk!(pr_emerg, $($f)*); }
+}
+
+/// Prints an alert-level message (level 1) prefixed with device information.
+///
+/// This level should be used if action must be taken immediately.
+///
+/// Equivalent to the kernel's `dev_alert` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+///     dev_alert!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_alert {
+    ($($f:tt)*) => { $crate::dev_printk!(pr_alert, $($f)*); }
+}
+
+/// Prints a critical-level message (level 2) prefixed with device information.
+///
+/// This level should be used in critical conditions.
+///
+/// Equivalent to the kernel's `dev_crit` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+///     dev_crit!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_crit {
+    ($($f:tt)*) => { $crate::dev_printk!(pr_crit, $($f)*); }
+}
+
+/// Prints an error-level message (level 3) prefixed with device information.
+///
+/// This level should be used in error conditions.
+///
+/// Equivalent to the kernel's `dev_err` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+///     dev_err!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_err {
+    ($($f:tt)*) => { $crate::dev_printk!(pr_err, $($f)*); }
+}
+
+/// Prints a warning-level message (level 4) prefixed with device information.
+///
+/// This level should be used in warning conditions.
+///
+/// Equivalent to the kernel's `dev_warn` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+///     dev_warn!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_warn {
+    ($($f:tt)*) => { $crate::dev_printk!(pr_warn, $($f)*); }
+}
+
+/// Prints a notice-level message (level 5) prefixed with device information.
+///
+/// This level should be used in normal but significant conditions.
+///
+/// Equivalent to the kernel's `dev_notice` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+///     dev_notice!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_notice {
+    ($($f:tt)*) => { $crate::dev_printk!(pr_notice, $($f)*); }
+}
+
+/// Prints an info-level message (level 6) prefixed with device information.
+///
+/// This level should be used for informational messages.
+///
+/// Equivalent to the kernel's `dev_info` macro.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+///     dev_info!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_info {
+    ($($f:tt)*) => { $crate::dev_printk!(pr_info, $($f)*); }
+}
+
+/// Prints a debug-level message (level 7) prefixed with device information.
+///
+/// This level should be used for debug messages.
+///
+/// Equivalent to the kernel's `dev_dbg` macro, except that it doesn't support dynamic debug yet.
+///
+/// Mimics the interface of [`std::print!`]. More information about the syntax is available from
+/// [`core::fmt`] and [`alloc::format!`].
+///
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::device::Device;
+///
+/// fn example(dev: &Device) {
+///     dev_dbg!(dev, "hello {}\n", "there");
+/// }
+/// ```
+#[macro_export]
+macro_rules! dev_dbg {
+    ($($f:tt)*) => { $crate::dev_printk!(pr_dbg, $($f)*); }
+}
diff --git a/rust/kernel/driver.rs b/rust/kernel/driver.rs
new file mode 100644
index 000000000000..82b39231e311
--- /dev/null
+++ b/rust/kernel/driver.rs
@@ -0,0 +1,442 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Generic support for drivers of different buses (e.g., PCI, Platform, Amba, etc.).
+//!
+//! Each bus/subsystem is expected to implement [`DriverOps`], which allows drivers to register
+//! using the [`Registration`] class.
+
+use crate::{error::code::*, str::CStr, sync::Ref, Result, ThisModule};
+use alloc::boxed::Box;
+use core::{cell::UnsafeCell, marker::PhantomData, ops::Deref, pin::Pin};
+
+/// A subsystem (e.g., PCI, Platform, Amba, etc.) that allows drivers to be written for it.
+pub trait DriverOps {
+    /// The type that holds information about the registration. This is typically a struct defined
+    /// by the C portion of the kernel.
+    type RegType: Default;
+
+    /// Registers a driver.
+    ///
+    /// # Safety
+    ///
+    /// `reg` must point to valid, initialised, and writable memory. It may be modified by this
+    /// function to hold registration state.
+    ///
+    /// On success, `reg` must remain pinned and valid until the matching call to
+    /// [`DriverOps::unregister`].
+    unsafe fn register(
+        reg: *mut Self::RegType,
+        name: &'static CStr,
+        module: &'static ThisModule,
+    ) -> Result;
+
+    /// Unregisters a driver previously registered with [`DriverOps::register`].
+    ///
+    /// # Safety
+    ///
+    /// `reg` must point to valid writable memory, initialised by a previous successful call to
+    /// [`DriverOps::register`].
+    unsafe fn unregister(reg: *mut Self::RegType);
+}
+
+/// The registration of a driver.
+pub struct Registration<T: DriverOps> {
+    is_registered: bool,
+    concrete_reg: UnsafeCell<T::RegType>,
+}
+
+// SAFETY: `Registration` has no fields or methods accessible via `&Registration`, so it is safe to
+// share references to it with multiple threads as nothing can be done.
+unsafe impl<T: DriverOps> Sync for Registration<T> {}
+
+impl<T: DriverOps> Registration<T> {
+    /// Creates a new instance of the registration object.
+    pub fn new() -> Self {
+        Self {
+            is_registered: false,
+            concrete_reg: UnsafeCell::new(T::RegType::default()),
+        }
+    }
+
+    /// Allocates a pinned registration object and registers it.
+    ///
+    /// Returns a pinned heap-allocated representation of the registration.
+    pub fn new_pinned(name: &'static CStr, module: &'static ThisModule) -> Result<Pin<Box<Self>>> {
+        let mut reg = Pin::from(Box::try_new(Self::new())?);
+        reg.as_mut().register(name, module)?;
+        Ok(reg)
+    }
+
+    /// Registers a driver with its subsystem.
+    ///
+    /// It must be pinned because the memory block that represents the registration is potentially
+    /// self-referential.
+    pub fn register(
+        self: Pin<&mut Self>,
+        name: &'static CStr,
+        module: &'static ThisModule,
+    ) -> Result {
+        // SAFETY: We never move out of `this`.
+        let this = unsafe { self.get_unchecked_mut() };
+        if this.is_registered {
+            // Already registered.
+            return Err(EINVAL);
+        }
+
+        // SAFETY: `concrete_reg` was initialised via its default constructor. It is only freed
+        // after `Self::drop` is called, which first calls `T::unregister`.
+        unsafe { T::register(this.concrete_reg.get(), name, module) }?;
+
+        this.is_registered = true;
+        Ok(())
+    }
+}
+
+impl<T: DriverOps> Default for Registration<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T: DriverOps> Drop for Registration<T> {
+    fn drop(&mut self) {
+        if self.is_registered {
+            // SAFETY: This path only runs if a previous call to `T::register` completed
+            // successfully.
+            unsafe { T::unregister(self.concrete_reg.get()) };
+        }
+    }
+}
+
+/// Conversion from a device id to a raw device id.
+///
+/// This is meant to be implemented by buses/subsystems so that they can use [`IdTable`] to
+/// guarantee (at compile-time) zero-termination of device id tables provided by drivers.
+///
+/// # Safety
+///
+/// Implementers must ensure that:
+///   - [`RawDeviceId::ZERO`] is actually a zeroed-out version of the raw device id.
+///   - [`RawDeviceId::to_rawid`] stores `offset` in the context/data field of the raw device id so
+///     that buses can recover the pointer to the data.
+pub unsafe trait RawDeviceId {
+    /// The raw type that holds the device id.
+    ///
+    /// Id tables created from [`Self`] are going to hold this type in its zero-terminated array.
+    type RawType: Copy;
+
+    /// A zeroed-out representation of the raw device id.
+    ///
+    /// Id tables created from [`Self`] use [`Self::ZERO`] as the sentinel to indicate the end of
+    /// the table.
+    const ZERO: Self::RawType;
+
+    /// Converts an id into a raw id.
+    ///
+    /// `offset` is the offset from the memory location where the raw device id is stored to the
+    /// location where its associated context information is stored. Implementations must store
+    /// this in the appropriate context/data field of the raw type.
+    fn to_rawid(&self, offset: isize) -> Self::RawType;
+}
+
+/// A zero-terminated device id array, followed by context data.
+#[repr(C)]
+pub struct IdArray<T: RawDeviceId, U, const N: usize> {
+    ids: [T::RawType; N],
+    sentinel: T::RawType,
+    id_infos: [Option<U>; N],
+}
+
+impl<T: RawDeviceId, U, const N: usize> IdArray<T, U, N> {
+    /// Creates a new instance of the array.
+    ///
+    /// The contents are derived from the given identifiers and context information.
+    pub const fn new(ids: [T; N], infos: [Option<U>; N]) -> Self
+    where
+        T: ~const RawDeviceId + Copy,
+    {
+        let mut array = Self {
+            ids: [T::ZERO; N],
+            sentinel: T::ZERO,
+            id_infos: infos,
+        };
+        let mut i = 0usize;
+        while i < N {
+            // SAFETY: Both pointers are within `array` (or one byte beyond), consequently they are
+            // derived from the same allocated object. We are using a `u8` pointer, whose size 1,
+            // so the pointers are necessarily 1-byte aligned.
+            let offset = unsafe {
+                (&array.id_infos[i] as *const _ as *const u8)
+                    .offset_from(&array.ids[i] as *const _ as _)
+            };
+            array.ids[i] = ids[i].to_rawid(offset);
+            i += 1;
+        }
+        array
+    }
+
+    /// Returns an `IdTable` backed by `self`.
+    ///
+    /// This is used to essentially erase the array size.
+    pub const fn as_table(&self) -> IdTable<'_, T, U> {
+        IdTable {
+            first: &self.ids[0],
+            _p: PhantomData,
+        }
+    }
+}
+
+/// A device id table.
+///
+/// The table is guaranteed to be zero-terminated and to be followed by an array of context data of
+/// type `Option<U>`.
+pub struct IdTable<'a, T: RawDeviceId, U> {
+    first: &'a T::RawType,
+    _p: PhantomData<&'a U>,
+}
+
+impl<T: RawDeviceId, U> const AsRef<T::RawType> for IdTable<'_, T, U> {
+    fn as_ref(&self) -> &T::RawType {
+        self.first
+    }
+}
+
+/// Counts the number of parenthesis-delimited, comma-separated items.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::count_paren_items;
+///
+/// assert_eq!(0, count_paren_items!());
+/// assert_eq!(1, count_paren_items!((A)));
+/// assert_eq!(1, count_paren_items!((A),));
+/// assert_eq!(2, count_paren_items!((A), (B)));
+/// assert_eq!(2, count_paren_items!((A), (B),));
+/// assert_eq!(3, count_paren_items!((A), (B), (C)));
+/// assert_eq!(3, count_paren_items!((A), (B), (C),));
+/// ```
+#[macro_export]
+macro_rules! count_paren_items {
+    (($($item:tt)*), $($remaining:tt)*) => { 1 + $crate::count_paren_items!($($remaining)*) };
+    (($($item:tt)*)) => { 1 };
+    () => { 0 };
+}
+
+/// Converts a comma-separated list of pairs into an array with the first element. That is, it
+/// discards the second element of the pair.
+///
+/// Additionally, it automatically introduces a type if the first element is warpped in curly
+/// braces, for example, if it's `{v: 10}`, it becomes `X { v: 10 }`; this is to avoid repeating
+/// the type.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::first_item;
+///
+/// #[derive(PartialEq, Debug)]
+/// struct X {
+///     v: u32,
+/// }
+///
+/// assert_eq!([] as [X; 0], first_item!(X, ));
+/// assert_eq!([X { v: 10 }], first_item!(X, ({ v: 10 }, Y)));
+/// assert_eq!([X { v: 10 }], first_item!(X, ({ v: 10 }, Y),));
+/// assert_eq!([X { v: 10 }], first_item!(X, (X { v: 10 }, Y)));
+/// assert_eq!([X { v: 10 }], first_item!(X, (X { v: 10 }, Y),));
+/// assert_eq!([X { v: 10 }, X { v: 20 }], first_item!(X, ({ v: 10 }, Y), ({ v: 20 }, Y)));
+/// assert_eq!([X { v: 10 }, X { v: 20 }], first_item!(X, ({ v: 10 }, Y), ({ v: 20 }, Y),));
+/// assert_eq!([X { v: 10 }, X { v: 20 }], first_item!(X, (X { v: 10 }, Y), (X { v: 20 }, Y)));
+/// assert_eq!([X { v: 10 }, X { v: 20 }], first_item!(X, (X { v: 10 }, Y), (X { v: 20 }, Y),));
+/// assert_eq!([X { v: 10 }, X { v: 20 }, X { v: 30 }],
+///            first_item!(X, ({ v: 10 }, Y), ({ v: 20 }, Y), ({v: 30}, Y)));
+/// assert_eq!([X { v: 10 }, X { v: 20 }, X { v: 30 }],
+///            first_item!(X, ({ v: 10 }, Y), ({ v: 20 }, Y), ({v: 30}, Y),));
+/// assert_eq!([X { v: 10 }, X { v: 20 }, X { v: 30 }],
+///            first_item!(X, (X { v: 10 }, Y), (X { v: 20 }, Y), (X {v: 30}, Y)));
+/// assert_eq!([X { v: 10 }, X { v: 20 }, X { v: 30 }],
+///            first_item!(X, (X { v: 10 }, Y), (X { v: 20 }, Y), (X {v: 30}, Y),));
+/// ```
+#[macro_export]
+macro_rules! first_item {
+    ($id_type:ty, $(({$($first:tt)*}, $second:expr)),* $(,)?) => {
+        {
+            type IdType = $id_type;
+            [$(IdType{$($first)*},)*]
+        }
+    };
+    ($id_type:ty, $(($first:expr, $second:expr)),* $(,)?) => { [$($first,)*] };
+}
+
+/// Converts a comma-separated list of pairs into an array with the second element. That is, it
+/// discards the first element of the pair.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::second_item;
+///
+/// assert_eq!([] as [u32; 0], second_item!());
+/// assert_eq!([10u32], second_item!((X, 10u32)));
+/// assert_eq!([10u32], second_item!((X, 10u32),));
+/// assert_eq!([10u32], second_item!(({ X }, 10u32)));
+/// assert_eq!([10u32], second_item!(({ X }, 10u32),));
+/// assert_eq!([10u32, 20], second_item!((X, 10u32), (X, 20)));
+/// assert_eq!([10u32, 20], second_item!((X, 10u32), (X, 20),));
+/// assert_eq!([10u32, 20], second_item!(({ X }, 10u32), ({ X }, 20)));
+/// assert_eq!([10u32, 20], second_item!(({ X }, 10u32), ({ X }, 20),));
+/// assert_eq!([10u32, 20, 30], second_item!((X, 10u32), (X, 20), (X, 30)));
+/// assert_eq!([10u32, 20, 30], second_item!((X, 10u32), (X, 20), (X, 30),));
+/// assert_eq!([10u32, 20, 30], second_item!(({ X }, 10u32), ({ X }, 20), ({ X }, 30)));
+/// assert_eq!([10u32, 20, 30], second_item!(({ X }, 10u32), ({ X }, 20), ({ X }, 30),));
+/// ```
+#[macro_export]
+macro_rules! second_item {
+    ($(({$($first:tt)*}, $second:expr)),* $(,)?) => { [$($second,)*] };
+    ($(($first:expr, $second:expr)),* $(,)?) => { [$($second,)*] };
+}
+
+/// Defines a new constant [`IdArray`] with a concise syntax.
+///
+/// It is meant to be used by buses and subsystems to create a similar macro with their device id
+/// type already specified, i.e., with fewer parameters to the end user.
+///
+/// # Examples
+///
+// TODO: Exported but not usable by kernel modules (requires `const_trait_impl`).
+/// ```ignore
+/// #![feature(const_trait_impl)]
+/// # use kernel::{define_id_array, driver::RawDeviceId};
+///
+/// #[derive(Copy, Clone)]
+/// struct Id(u32);
+///
+/// // SAFETY: `ZERO` is all zeroes and `to_rawid` stores `offset` as the second element of the raw
+/// // device id pair.
+/// unsafe impl const RawDeviceId for Id {
+///     type RawType = (u64, isize);
+///     const ZERO: Self::RawType = (0, 0);
+///     fn to_rawid(&self, offset: isize) -> Self::RawType {
+///         (self.0 as u64 + 1, offset)
+///     }
+/// }
+///
+/// define_id_array!(A1, Id, (), []);
+/// define_id_array!(A2, Id, &'static [u8], [(Id(10), None)]);
+/// define_id_array!(A3, Id, &'static [u8], [(Id(10), Some(b"id1")), ]);
+/// define_id_array!(A4, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), Some(b"id2"))]);
+/// define_id_array!(A5, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), Some(b"id2")), ]);
+/// define_id_array!(A6, Id, &'static [u8], [(Id(10), None), (Id(20), Some(b"id2")), ]);
+/// define_id_array!(A7, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), None), ]);
+/// define_id_array!(A8, Id, &'static [u8], [(Id(10), None), (Id(20), None), ]);
+/// ```
+#[macro_export]
+macro_rules! define_id_array {
+    ($table_name:ident, $id_type:ty, $data_type:ty, [ $($t:tt)* ]) => {
+        const $table_name:
+            $crate::driver::IdArray<$id_type, $data_type, { $crate::count_paren_items!($($t)*) }> =
+                $crate::driver::IdArray::new(
+                    $crate::first_item!($id_type, $($t)*), $crate::second_item!($($t)*));
+    };
+}
+
+/// Defines a new constant [`IdTable`] with a concise syntax.
+///
+/// It is meant to be used by buses and subsystems to create a similar macro with their device id
+/// type already specified, i.e., with fewer parameters to the end user.
+///
+/// # Examples
+///
+// TODO: Exported but not usable by kernel modules (requires `const_trait_impl`).
+/// ```ignore
+/// #![feature(const_trait_impl)]
+/// # use kernel::{define_id_table, driver::RawDeviceId};
+///
+/// #[derive(Copy, Clone)]
+/// struct Id(u32);
+///
+/// // SAFETY: `ZERO` is all zeroes and `to_rawid` stores `offset` as the second element of the raw
+/// // device id pair.
+/// unsafe impl const RawDeviceId for Id {
+///     type RawType = (u64, isize);
+///     const ZERO: Self::RawType = (0, 0);
+///     fn to_rawid(&self, offset: isize) -> Self::RawType {
+///         (self.0 as u64 + 1, offset)
+///     }
+/// }
+///
+/// define_id_table!(T1, Id, &'static [u8], [(Id(10), None)]);
+/// define_id_table!(T2, Id, &'static [u8], [(Id(10), Some(b"id1")), ]);
+/// define_id_table!(T3, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), Some(b"id2"))]);
+/// define_id_table!(T4, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), Some(b"id2")), ]);
+/// define_id_table!(T5, Id, &'static [u8], [(Id(10), None), (Id(20), Some(b"id2")), ]);
+/// define_id_table!(T6, Id, &'static [u8], [(Id(10), Some(b"id1")), (Id(20), None), ]);
+/// define_id_table!(T7, Id, &'static [u8], [(Id(10), None), (Id(20), None), ]);
+/// ```
+#[macro_export]
+macro_rules! define_id_table {
+    ($table_name:ident, $id_type:ty, $data_type:ty, [ $($t:tt)* ]) => {
+        const $table_name: Option<$crate::driver::IdTable<'static, $id_type, $data_type>> = {
+            $crate::define_id_array!(ARRAY, $id_type, $data_type, [ $($t)* ]);
+            Some(ARRAY.as_table())
+        };
+    };
+}
+
+/// Custom code within device removal.
+pub trait DeviceRemoval {
+    /// Cleans resources up when the device is removed.
+    ///
+    /// This is called when a device is removed and offers implementers the chance to run some code
+    /// that cleans state up.
+    fn device_remove(&self);
+}
+
+impl DeviceRemoval for () {
+    fn device_remove(&self) {}
+}
+
+impl<T: DeviceRemoval> DeviceRemoval for Ref<T> {
+    fn device_remove(&self) {
+        self.deref().device_remove();
+    }
+}
+
+impl<T: DeviceRemoval> DeviceRemoval for Box<T> {
+    fn device_remove(&self) {
+        self.deref().device_remove();
+    }
+}
+
+/// A kernel module that only registers the given driver on init.
+///
+/// This is a helper struct to make it easier to define single-functionality modules, in this case,
+/// modules that offer a single driver.
+pub struct Module<T: DriverOps> {
+    _driver: Pin<Box<Registration<T>>>,
+}
+
+impl<T: DriverOps> crate::Module for Module<T> {
+    fn init(name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+        Ok(Self {
+            _driver: Registration::new_pinned(name, module)?,
+        })
+    }
+}
+
+/// Declares a kernel module that exposes a single driver.
+///
+/// It is meant to be used as a helper by other subsystems so they can more easily expose their own
+/// macros.
+#[macro_export]
+macro_rules! module_driver {
+    (<$gen_type:ident>, $driver_ops:ty, { type: $type:ty, $($f:tt)* }) => {
+        type Ops<$gen_type> = $driver_ops;
+        type ModuleType = $crate::driver::Module<Ops<$type>>;
+        $crate::prelude::module! {
+            type: ModuleType,
+            $($f)*
+        }
+    }
+}
diff --git a/rust/kernel/error.rs b/rust/kernel/error.rs
new file mode 100644
index 000000000000..f968aa91ddf2
--- /dev/null
+++ b/rust/kernel/error.rs
@@ -0,0 +1,564 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel errors.
+//!
+//! C header: [`include/uapi/asm-generic/errno-base.h`](../../../include/uapi/asm-generic/errno-base.h)
+
+use crate::bindings;
+use crate::str::CStr;
+use alloc::{
+    alloc::{AllocError, LayoutError},
+    collections::TryReserveError,
+};
+use core::convert::From;
+use core::fmt;
+use core::num::TryFromIntError;
+use core::str::{self, Utf8Error};
+
+/// Contains the C-compatible error codes.
+pub mod code {
+    macro_rules! declare_err {
+        ($err:tt $(,)? $($doc:expr),+) => {
+            $(
+            #[doc = $doc]
+            )*
+            pub const $err: super::Error = super::Error(-(crate::bindings::$err as i32));
+        };
+    }
+
+    declare_err!(EPERM, "Operation not permitted.");
+
+    declare_err!(ENOENT, "No such file or directory.");
+
+    declare_err!(ESRCH, "No such process.");
+
+    declare_err!(EINTR, "Interrupted system call.");
+
+    declare_err!(EIO, "I/O error.");
+
+    declare_err!(ENXIO, "No such device or address.");
+
+    declare_err!(E2BIG, "Argument list too long.");
+
+    declare_err!(ENOEXEC, "Exec format error.");
+
+    declare_err!(EBADF, "Bad file number.");
+
+    declare_err!(ECHILD, "Exec format error.");
+
+    declare_err!(EAGAIN, "Try again.");
+
+    declare_err!(ENOMEM, "Out of memory.");
+
+    declare_err!(EACCES, "Permission denied.");
+
+    declare_err!(EFAULT, "Bad address.");
+
+    declare_err!(ENOTBLK, "Block device required.");
+
+    declare_err!(EBUSY, "Device or resource busy.");
+
+    declare_err!(EEXIST, "File exists.");
+
+    declare_err!(EXDEV, "Cross-device link.");
+
+    declare_err!(ENODEV, "No such device.");
+
+    declare_err!(ENOTDIR, "Not a directory.");
+
+    declare_err!(EISDIR, "Is a directory.");
+
+    declare_err!(EINVAL, "Invalid argument.");
+
+    declare_err!(ENFILE, "File table overflow.");
+
+    declare_err!(EMFILE, "Too many open files.");
+
+    declare_err!(ENOTTY, "Not a typewriter.");
+
+    declare_err!(ETXTBSY, "Text file busy.");
+
+    declare_err!(EFBIG, "File too large.");
+
+    declare_err!(ENOSPC, "No space left on device.");
+
+    declare_err!(ESPIPE, "Illegal seek.");
+
+    declare_err!(EROFS, "Read-only file system.");
+
+    declare_err!(EMLINK, "Too many links.");
+
+    declare_err!(EPIPE, "Broken pipe.");
+
+    declare_err!(EDOM, "Math argument out of domain of func.");
+
+    declare_err!(ERANGE, "Math result not representable.");
+
+    declare_err!(EDEADLK, "Resource deadlock would occur");
+
+    declare_err!(ENAMETOOLONG, "File name too long");
+
+    declare_err!(ENOLCK, "No record locks available");
+
+    declare_err!(
+        ENOSYS,
+        "Invalid system call number.",
+        "",
+        "This error code is special: arch syscall entry code will return",
+        "[`ENOSYS`] if users try to call a syscall that doesn't exist.",
+        "To keep failures of syscalls that really do exist distinguishable from",
+        "failures due to attempts to use a nonexistent syscall, syscall",
+        "implementations should refrain from returning [`ENOSYS`]."
+    );
+
+    declare_err!(ENOTEMPTY, "Directory not empty.");
+
+    declare_err!(ELOOP, "Too many symbolic links encountered.");
+
+    declare_err!(EWOULDBLOCK, "Operation would block.");
+
+    declare_err!(ENOMSG, "No message of desired type.");
+
+    declare_err!(EIDRM, "Identifier removed.");
+
+    declare_err!(ECHRNG, "Channel number out of range.");
+
+    declare_err!(EL2NSYNC, "Level 2 not synchronized.");
+
+    declare_err!(EL3HLT, "Level 3 halted.");
+
+    declare_err!(EL3RST, "Level 3 reset.");
+
+    declare_err!(ELNRNG, "Link number out of range.");
+
+    declare_err!(EUNATCH, "Protocol driver not attached.");
+
+    declare_err!(ENOCSI, "No CSI structure available.");
+
+    declare_err!(EL2HLT, "Level 2 halted.");
+
+    declare_err!(EBADE, "Invalid exchange.");
+
+    declare_err!(EBADR, "Invalid request descriptor.");
+
+    declare_err!(EXFULL, "Exchange full.");
+
+    declare_err!(ENOANO, "No anode.");
+
+    declare_err!(EBADRQC, "Invalid request code.");
+
+    declare_err!(EBADSLT, "Invalid slot.");
+
+    declare_err!(EDEADLOCK, "Resource deadlock would occur.");
+
+    declare_err!(EBFONT, "Bad font file format.");
+
+    declare_err!(ENOSTR, "Device not a stream.");
+
+    declare_err!(ENODATA, "No data available.");
+
+    declare_err!(ETIME, "Timer expired.");
+
+    declare_err!(ENOSR, "Out of streams resources.");
+
+    declare_err!(ENONET, "Machine is not on the network.");
+
+    declare_err!(ENOPKG, "Package not installed.");
+
+    declare_err!(EREMOTE, "Object is remote.");
+
+    declare_err!(ENOLINK, "Link has been severed.");
+
+    declare_err!(EADV, "Advertise error.");
+
+    declare_err!(ESRMNT, "Srmount error.");
+
+    declare_err!(ECOMM, "Communication error on send.");
+
+    declare_err!(EPROTO, "Protocol error.");
+
+    declare_err!(EMULTIHOP, "Multihop attempted.");
+
+    declare_err!(EDOTDOT, "RFS specific error.");
+
+    declare_err!(EBADMSG, "Not a data message.");
+
+    declare_err!(EOVERFLOW, "Value too large for defined data type.");
+
+    declare_err!(ENOTUNIQ, "Name not unique on network.");
+
+    declare_err!(EBADFD, "File descriptor in bad state.");
+
+    declare_err!(EREMCHG, "Remote address changed.");
+
+    declare_err!(ELIBACC, "Can not access a needed shared library.");
+
+    declare_err!(ELIBBAD, "Accessing a corrupted shared library.");
+
+    declare_err!(ELIBSCN, ".lib section in a.out corrupted.");
+
+    declare_err!(ELIBMAX, "Attempting to link in too many shared libraries.");
+
+    declare_err!(ELIBEXEC, "Cannot exec a shared library directly.");
+
+    declare_err!(EILSEQ, "Illegal byte sequence.");
+
+    declare_err!(ERESTART, "Interrupted system call should be restarted.");
+
+    declare_err!(ESTRPIPE, "Streams pipe error.");
+
+    declare_err!(EUSERS, "Too many users.");
+
+    declare_err!(ENOTSOCK, "Socket operation on non-socket.");
+
+    declare_err!(EDESTADDRREQ, "Destination address required.");
+
+    declare_err!(EMSGSIZE, "Message too long.");
+
+    declare_err!(EPROTOTYPE, "Protocol wrong type for socket.");
+
+    declare_err!(ENOPROTOOPT, "Protocol not available.");
+
+    declare_err!(EPROTONOSUPPORT, "Protocol not supported.");
+
+    declare_err!(ESOCKTNOSUPPORT, "Socket type not supported.");
+
+    declare_err!(EOPNOTSUPP, "Operation not supported on transport endpoint.");
+
+    declare_err!(EPFNOSUPPORT, "Protocol family not supported.");
+
+    declare_err!(EAFNOSUPPORT, "Address family not supported by protocol.");
+
+    declare_err!(EADDRINUSE, "Address already in use.");
+
+    declare_err!(EADDRNOTAVAIL, "Cannot assign requested address.");
+
+    declare_err!(ENETDOWN, "Network is down.");
+
+    declare_err!(ENETUNREACH, "Network is unreachable.");
+
+    declare_err!(ENETRESET, "Network dropped connection because of reset.");
+
+    declare_err!(ECONNABORTED, "Software caused connection abort.");
+
+    declare_err!(ECONNRESET, "Connection reset by peer.");
+
+    declare_err!(ENOBUFS, "No buffer space available.");
+
+    declare_err!(EISCONN, "Transport endpoint is already connected.");
+
+    declare_err!(ENOTCONN, "Transport endpoint is not connected.");
+
+    declare_err!(ESHUTDOWN, "Cannot send after transport endpoint shutdown.");
+
+    declare_err!(ETOOMANYREFS, "Too many references: cannot splice.");
+
+    declare_err!(ETIMEDOUT, "Connection timed out.");
+
+    declare_err!(ECONNREFUSED, "Connection refused.");
+
+    declare_err!(EHOSTDOWN, "Host is down.");
+
+    declare_err!(EHOSTUNREACH, "No route to host.");
+
+    declare_err!(EALREADY, "Operation already in progress.");
+
+    declare_err!(EINPROGRESS, "Operation now in progress.");
+
+    declare_err!(ESTALE, "Stale file handle.");
+
+    declare_err!(EUCLEAN, "Structure needs cleaning.");
+
+    declare_err!(ENOTNAM, "Not a XENIX named type file.");
+
+    declare_err!(ENAVAIL, "No XENIX semaphores available.");
+
+    declare_err!(EISNAM, "Is a named type file.");
+
+    declare_err!(EREMOTEIO, "Remote I/O error.");
+
+    declare_err!(EDQUOT, "Quota exceeded.");
+
+    declare_err!(ENOMEDIUM, "No medium found.");
+
+    declare_err!(EMEDIUMTYPE, "Wrong medium type.");
+
+    declare_err!(ECANCELED, "Operation Canceled.");
+
+    declare_err!(ENOKEY, "Required key not available.");
+
+    declare_err!(EKEYEXPIRED, "Key has expired.");
+
+    declare_err!(EKEYREVOKED, "Key has been revoked.");
+
+    declare_err!(EKEYREJECTED, "Key was rejected by service.");
+
+    declare_err!(EOWNERDEAD, "Owner died.", "", "For robust mutexes.");
+
+    declare_err!(ENOTRECOVERABLE, "State not recoverable.");
+
+    declare_err!(ERFKILL, "Operation not possible due to RF-kill.");
+
+    declare_err!(EHWPOISON, "Memory page has hardware error.");
+
+    declare_err!(ERESTARTSYS, "Restart the system call.");
+
+    declare_err!(ENOTSUPP, "Operation is not supported.");
+
+    declare_err!(ENOPARAM, "Parameter not supported.");
+}
+
+/// Generic integer kernel error.
+///
+/// The kernel defines a set of integer generic error codes based on C and
+/// POSIX ones. These codes may have a more specific meaning in some contexts.
+///
+/// # Invariants
+///
+/// The value is a valid `errno` (i.e. `>= -MAX_ERRNO && < 0`).
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct Error(core::ffi::c_int);
+
+impl Error {
+    /// Creates an [`Error`] from a kernel error code.
+    ///
+    /// It is a bug to pass an out-of-range `errno`. `EINVAL` would
+    /// be returned in such a case.
+    pub(crate) fn from_kernel_errno(errno: core::ffi::c_int) -> Error {
+        if errno < -(bindings::MAX_ERRNO as i32) || errno >= 0 {
+            // TODO: Make it a `WARN_ONCE` once available.
+            crate::pr_warn!(
+                "attempted to create `Error` with out of range `errno`: {}",
+                errno
+            );
+            return code::EINVAL;
+        }
+
+        // INVARIANT: The check above ensures the type invariant
+        // will hold.
+        Error(errno)
+    }
+
+    /// Creates an [`Error`] from a kernel error code.
+    ///
+    /// # Safety
+    ///
+    /// `errno` must be within error code range (i.e. `>= -MAX_ERRNO && < 0`).
+    pub(crate) unsafe fn from_kernel_errno_unchecked(errno: core::ffi::c_int) -> Error {
+        // INVARIANT: The contract ensures the type invariant
+        // will hold.
+        Error(errno)
+    }
+
+    /// Returns the kernel error code.
+    pub fn to_kernel_errno(self) -> core::ffi::c_int {
+        self.0
+    }
+
+    /// Returns a string representing the error, if one exists.
+    #[cfg(not(testlib))]
+    pub fn name(&self) -> Option<&'static CStr> {
+        // SAFETY: Just an FFI call, there are no extra safety requirements.
+        let ptr = unsafe { bindings::errname(-self.0) };
+        if ptr.is_null() {
+            None
+        } else {
+            // SAFETY: The string returned by `errname` is static and `NUL`-terminated.
+            Some(unsafe { CStr::from_char_ptr(ptr) })
+        }
+    }
+
+    /// Returns a string representing the error, if one exists.
+    ///
+    /// When `testlib` is configured, this always returns `None` to avoid the dependency on a
+    /// kernel function so that tests that use this (e.g., by calling [`Result::unwrap`]) can still
+    /// run in userspace.
+    #[cfg(testlib)]
+    pub fn name(&self) -> Option<&'static CStr> {
+        None
+    }
+}
+
+impl fmt::Debug for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self.name() {
+            // Print out number if no name can be found.
+            None => f.debug_tuple("Error").field(&-self.0).finish(),
+            // SAFETY: These strings are ASCII-only.
+            Some(name) => f
+                .debug_tuple(unsafe { str::from_utf8_unchecked(name) })
+                .finish(),
+        }
+    }
+}
+
+impl From<TryFromIntError> for Error {
+    fn from(_: TryFromIntError) -> Error {
+        code::EINVAL
+    }
+}
+
+impl From<Utf8Error> for Error {
+    fn from(_: Utf8Error) -> Error {
+        code::EINVAL
+    }
+}
+
+impl From<TryReserveError> for Error {
+    fn from(_: TryReserveError) -> Error {
+        code::ENOMEM
+    }
+}
+
+impl From<LayoutError> for Error {
+    fn from(_: LayoutError) -> Error {
+        code::ENOMEM
+    }
+}
+
+impl From<core::fmt::Error> for Error {
+    fn from(_: core::fmt::Error) -> Error {
+        code::EINVAL
+    }
+}
+
+impl From<core::convert::Infallible> for Error {
+    fn from(e: core::convert::Infallible) -> Error {
+        match e {}
+    }
+}
+
+/// A [`Result`] with an [`Error`] error type.
+///
+/// To be used as the return type for functions that may fail.
+///
+/// # Error codes in C and Rust
+///
+/// In C, it is common that functions indicate success or failure through
+/// their return value; modifying or returning extra data through non-`const`
+/// pointer parameters. In particular, in the kernel, functions that may fail
+/// typically return an `int` that represents a generic error code. We model
+/// those as [`Error`].
+///
+/// In Rust, it is idiomatic to model functions that may fail as returning
+/// a [`Result`]. Since in the kernel many functions return an error code,
+/// [`Result`] is a type alias for a [`core::result::Result`] that uses
+/// [`Error`] as its error type.
+///
+/// Note that even if a function does not return anything when it succeeds,
+/// it should still be modeled as returning a `Result` rather than
+/// just an [`Error`].
+pub type Result<T = ()> = core::result::Result<T, Error>;
+
+impl From<AllocError> for Error {
+    fn from(_: AllocError) -> Error {
+        code::ENOMEM
+    }
+}
+
+// # Invariant: `-bindings::MAX_ERRNO` fits in an `i16`.
+crate::static_assert!(bindings::MAX_ERRNO <= -(i16::MIN as i32) as u32);
+
+pub(crate) fn from_kernel_result_helper<T>(r: Result<T>) -> T
+where
+    T: From<i16>,
+{
+    match r {
+        Ok(v) => v,
+        // NO-OVERFLOW: negative `errno`s are no smaller than `-bindings::MAX_ERRNO`,
+        // `-bindings::MAX_ERRNO` fits in an `i16` as per invariant above,
+        // therefore a negative `errno` always fits in an `i16` and will not overflow.
+        Err(e) => T::from(e.to_kernel_errno() as i16),
+    }
+}
+
+/// Transforms a [`crate::error::Result<T>`] to a kernel C integer result.
+///
+/// This is useful when calling Rust functions that return [`crate::error::Result<T>`]
+/// from inside `extern "C"` functions that need to return an integer
+/// error result.
+///
+/// `T` should be convertible to an `i16` via `From<i16>`.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::from_kernel_result;
+/// # use kernel::bindings;
+/// unsafe extern "C" fn probe_callback(
+///     pdev: *mut bindings::platform_device,
+/// ) -> core::ffi::c_int {
+///     from_kernel_result! {
+///         let ptr = devm_alloc(pdev)?;
+///         bindings::platform_set_drvdata(pdev, ptr);
+///         Ok(0)
+///     }
+/// }
+/// ```
+macro_rules! from_kernel_result {
+    ($($tt:tt)*) => {{
+        $crate::error::from_kernel_result_helper((|| {
+            $($tt)*
+        })())
+    }};
+}
+
+pub(crate) use from_kernel_result;
+
+/// Transform a kernel "error pointer" to a normal pointer.
+///
+/// Some kernel C API functions return an "error pointer" which optionally
+/// embeds an `errno`. Callers are supposed to check the returned pointer
+/// for errors. This function performs the check and converts the "error pointer"
+/// to a normal pointer in an idiomatic fashion.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::from_kernel_err_ptr;
+/// # use kernel::bindings;
+/// fn devm_platform_ioremap_resource(
+///     pdev: &mut PlatformDevice,
+///     index: u32,
+/// ) -> Result<*mut core::ffi::c_void> {
+///     // SAFETY: FFI call.
+///     unsafe {
+///         from_kernel_err_ptr(bindings::devm_platform_ioremap_resource(
+///             pdev.to_ptr(),
+///             index,
+///         ))
+///     }
+/// }
+/// ```
+// TODO: Remove `dead_code` marker once an in-kernel client is available.
+#[allow(dead_code)]
+pub(crate) fn from_kernel_err_ptr<T>(ptr: *mut T) -> Result<*mut T> {
+    // CAST: Casting a pointer to `*const core::ffi::c_void` is always valid.
+    let const_ptr: *const core::ffi::c_void = ptr.cast();
+    // SAFETY: The FFI function does not deref the pointer.
+    if unsafe { bindings::IS_ERR(const_ptr) } {
+        // SAFETY: The FFI function does not deref the pointer.
+        let err = unsafe { bindings::PTR_ERR(const_ptr) };
+        // CAST: If `IS_ERR()` returns `true`,
+        // then `PTR_ERR()` is guaranteed to return a
+        // negative value greater-or-equal to `-bindings::MAX_ERRNO`,
+        // which always fits in an `i16`, as per the invariant above.
+        // And an `i16` always fits in an `i32`. So casting `err` to
+        // an `i32` can never overflow, and is always valid.
+        //
+        // SAFETY: `IS_ERR()` ensures `err` is a
+        // negative value greater-or-equal to `-bindings::MAX_ERRNO`.
+        return Err(unsafe { Error::from_kernel_errno_unchecked(err as i32) });
+    }
+    Ok(ptr)
+}
+
+/// Converts an integer as returned by a C kernel function to an error if it's negative, and
+/// `Ok(())` otherwise.
+pub fn to_result(err: core::ffi::c_int) -> Result {
+    if err < 0 {
+        Err(Error::from_kernel_errno(err))
+    } else {
+        Ok(())
+    }
+}
diff --git a/rust/kernel/file.rs b/rust/kernel/file.rs
new file mode 100644
index 000000000000..62538e6b3eea
--- /dev/null
+++ b/rust/kernel/file.rs
@@ -0,0 +1,887 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Files and file descriptors.
+//!
+//! C headers: [`include/linux/fs.h`](../../../../include/linux/fs.h) and
+//! [`include/linux/file.h`](../../../../include/linux/file.h)
+
+use crate::{
+    bindings,
+    cred::Credential,
+    error::{code::*, from_kernel_result, Error, Result},
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    iov_iter::IovIter,
+    mm,
+    sync::CondVar,
+    types::PointerWrapper,
+    user_ptr::{UserSlicePtr, UserSlicePtrReader, UserSlicePtrWriter},
+    ARef, AlwaysRefCounted,
+};
+use core::convert::{TryFrom, TryInto};
+use core::{cell::UnsafeCell, marker, mem, ptr};
+use macros::vtable;
+
+/// Flags associated with a [`File`].
+pub mod flags {
+    /// File is opened in append mode.
+    pub const O_APPEND: u32 = bindings::O_APPEND;
+
+    /// Signal-driven I/O is enabled.
+    pub const O_ASYNC: u32 = bindings::FASYNC;
+
+    /// Close-on-exec flag is set.
+    pub const O_CLOEXEC: u32 = bindings::O_CLOEXEC;
+
+    /// File was created if it didn't already exist.
+    pub const O_CREAT: u32 = bindings::O_CREAT;
+
+    /// Direct I/O is enabled for this file.
+    pub const O_DIRECT: u32 = bindings::O_DIRECT;
+
+    /// File must be a directory.
+    pub const O_DIRECTORY: u32 = bindings::O_DIRECTORY;
+
+    /// Like [`O_SYNC`] except metadata is not synced.
+    pub const O_DSYNC: u32 = bindings::O_DSYNC;
+
+    /// Ensure that this file is created with the `open(2)` call.
+    pub const O_EXCL: u32 = bindings::O_EXCL;
+
+    /// Large file size enabled (`off64_t` over `off_t`).
+    pub const O_LARGEFILE: u32 = bindings::O_LARGEFILE;
+
+    /// Do not update the file last access time.
+    pub const O_NOATIME: u32 = bindings::O_NOATIME;
+
+    /// File should not be used as process's controlling terminal.
+    pub const O_NOCTTY: u32 = bindings::O_NOCTTY;
+
+    /// If basename of path is a symbolic link, fail open.
+    pub const O_NOFOLLOW: u32 = bindings::O_NOFOLLOW;
+
+    /// File is using nonblocking I/O.
+    pub const O_NONBLOCK: u32 = bindings::O_NONBLOCK;
+
+    /// Also known as `O_NDELAY`.
+    ///
+    /// This is effectively the same flag as [`O_NONBLOCK`] on all architectures
+    /// except SPARC64.
+    pub const O_NDELAY: u32 = bindings::O_NDELAY;
+
+    /// Used to obtain a path file descriptor.
+    pub const O_PATH: u32 = bindings::O_PATH;
+
+    /// Write operations on this file will flush data and metadata.
+    pub const O_SYNC: u32 = bindings::O_SYNC;
+
+    /// This file is an unnamed temporary regular file.
+    pub const O_TMPFILE: u32 = bindings::O_TMPFILE;
+
+    /// File should be truncated to length 0.
+    pub const O_TRUNC: u32 = bindings::O_TRUNC;
+
+    /// Bitmask for access mode flags.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use kernel::file;
+    /// # fn do_something() {}
+    /// # let flags = 0;
+    /// if (flags & file::flags::O_ACCMODE) == file::flags::O_RDONLY {
+    ///     do_something();
+    /// }
+    /// ```
+    pub const O_ACCMODE: u32 = bindings::O_ACCMODE;
+
+    /// File is read only.
+    pub const O_RDONLY: u32 = bindings::O_RDONLY;
+
+    /// File is write only.
+    pub const O_WRONLY: u32 = bindings::O_WRONLY;
+
+    /// File can be both read and written.
+    pub const O_RDWR: u32 = bindings::O_RDWR;
+}
+
+/// Wraps the kernel's `struct file`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `get_file` ensures that the
+/// allocation remains valid at least until the matching call to `fput`.
+#[repr(transparent)]
+pub struct File(pub(crate) UnsafeCell<bindings::file>);
+
+// TODO: Accessing fields of `struct file` through the pointer is UB because other threads may be
+// writing to them. However, this is how the C code currently operates: naked reads and writes to
+// fields. Even if we used relaxed atomics on the Rust side, we can't force this on the C side.
+impl File {
+    /// Constructs a new [`struct file`] wrapper from a file descriptor.
+    ///
+    /// The file descriptor belongs to the current process.
+    pub fn from_fd(fd: u32) -> Result<ARef<Self>> {
+        // SAFETY: FFI call, there are no requirements on `fd`.
+        let ptr = ptr::NonNull::new(unsafe { bindings::fget(fd) }).ok_or(EBADF)?;
+
+        // SAFETY: `fget` increments the refcount before returning.
+        Ok(unsafe { ARef::from_raw(ptr.cast()) })
+    }
+
+    /// Creates a reference to a [`File`] from a valid pointer.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
+    /// returned [`File`] instance.
+    pub(crate) unsafe fn from_ptr<'a>(ptr: *const bindings::file) -> &'a File {
+        // SAFETY: The safety requirements guarantee the validity of the dereference, while the
+        // `File` type being transparent makes the cast ok.
+        unsafe { &*ptr.cast() }
+    }
+
+    /// Returns the current seek/cursor/pointer position (`struct file::f_pos`).
+    pub fn pos(&self) -> u64 {
+        // SAFETY: The file is valid because the shared reference guarantees a nonzero refcount.
+        unsafe { core::ptr::addr_of!((*self.0.get()).f_pos).read() as _ }
+    }
+
+    /// Returns the credentials of the task that originally opened the file.
+    pub fn cred(&self) -> &Credential {
+        // SAFETY: The file is valid because the shared reference guarantees a nonzero refcount.
+        let ptr = unsafe { core::ptr::addr_of!((*self.0.get()).f_cred).read() };
+        // SAFETY: The lifetimes of `self` and `Credential` are tied, so it is guaranteed that
+        // the credential pointer remains valid (because the file is still alive, and it doesn't
+        // change over the lifetime of a file).
+        unsafe { Credential::from_ptr(ptr) }
+    }
+
+    /// Returns the flags associated with the file.
+    ///
+    /// The flags are a combination of the constants in [`flags`].
+    pub fn flags(&self) -> u32 {
+        // SAFETY: The file is valid because the shared reference guarantees a nonzero refcount.
+        unsafe { core::ptr::addr_of!((*self.0.get()).f_flags).read() }
+    }
+}
+
+// SAFETY: The type invariants guarantee that `File` is always ref-counted.
+unsafe impl AlwaysRefCounted for File {
+    fn inc_ref(&self) {
+        // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+        unsafe { bindings::get_file(self.0.get()) };
+    }
+
+    unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
+        // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+        unsafe { bindings::fput(obj.cast().as_ptr()) }
+    }
+}
+
+/// A file descriptor reservation.
+///
+/// This allows the creation of a file descriptor in two steps: first, we reserve a slot for it,
+/// then we commit or drop the reservation. The first step may fail (e.g., the current process ran
+/// out of available slots), but commit and drop never fail (and are mutually exclusive).
+pub struct FileDescriptorReservation {
+    fd: u32,
+}
+
+impl FileDescriptorReservation {
+    /// Creates a new file descriptor reservation.
+    pub fn new(flags: u32) -> Result<Self> {
+        // SAFETY: FFI call, there are no safety requirements on `flags`.
+        let fd = unsafe { bindings::get_unused_fd_flags(flags) };
+        if fd < 0 {
+            return Err(Error::from_kernel_errno(fd));
+        }
+        Ok(Self { fd: fd as _ })
+    }
+
+    /// Returns the file descriptor number that was reserved.
+    pub fn reserved_fd(&self) -> u32 {
+        self.fd
+    }
+
+    /// Commits the reservation.
+    ///
+    /// The previously reserved file descriptor is bound to `file`.
+    pub fn commit(self, file: ARef<File>) {
+        // SAFETY: `self.fd` was previously returned by `get_unused_fd_flags`, and `file.ptr` is
+        // guaranteed to have an owned ref count by its type invariants.
+        unsafe { bindings::fd_install(self.fd, file.0.get()) };
+
+        // `fd_install` consumes both the file descriptor and the file reference, so we cannot run
+        // the destructors.
+        core::mem::forget(self);
+        core::mem::forget(file);
+    }
+}
+
+impl Drop for FileDescriptorReservation {
+    fn drop(&mut self) {
+        // SAFETY: `self.fd` was returned by a previous call to `get_unused_fd_flags`.
+        unsafe { bindings::put_unused_fd(self.fd) };
+    }
+}
+
+/// Wraps the kernel's `struct poll_table_struct`.
+///
+/// # Invariants
+///
+/// The pointer `PollTable::ptr` is null or valid.
+pub struct PollTable {
+    ptr: *mut bindings::poll_table_struct,
+}
+
+impl PollTable {
+    /// Constructors a new `struct poll_table_struct` wrapper.
+    ///
+    /// # Safety
+    ///
+    /// The pointer `ptr` must be either null or a valid pointer for the lifetime of the object.
+    unsafe fn from_ptr(ptr: *mut bindings::poll_table_struct) -> Self {
+        Self { ptr }
+    }
+
+    /// Associates the given file and condition variable to this poll table. It means notifying the
+    /// condition variable will notify the poll table as well; additionally, the association
+    /// between the condition variable and the file will automatically be undone by the kernel when
+    /// the file is destructed. To unilaterally remove the association before then, one can call
+    /// [`CondVar::free_waiters`].
+    ///
+    /// # Safety
+    ///
+    /// If the condition variable is destroyed before the file, then [`CondVar::free_waiters`] must
+    /// be called to ensure that all waiters are flushed out.
+    pub unsafe fn register_wait<'a>(&self, file: &'a File, cv: &'a CondVar) {
+        if self.ptr.is_null() {
+            return;
+        }
+
+        // SAFETY: `PollTable::ptr` is guaranteed to be valid by the type invariants and the null
+        // check above.
+        let table = unsafe { &*self.ptr };
+        if let Some(proc) = table._qproc {
+            // SAFETY: All pointers are known to be valid.
+            unsafe { proc(file.0.get() as _, cv.wait_list.get(), self.ptr) }
+        }
+    }
+}
+
+/// Equivalent to [`std::io::SeekFrom`].
+///
+/// [`std::io::SeekFrom`]: https://doc.rust-lang.org/std/io/enum.SeekFrom.html
+pub enum SeekFrom {
+    /// Equivalent to C's `SEEK_SET`.
+    Start(u64),
+
+    /// Equivalent to C's `SEEK_END`.
+    End(i64),
+
+    /// Equivalent to C's `SEEK_CUR`.
+    Current(i64),
+}
+
+pub(crate) struct OperationsVtable<A, T>(marker::PhantomData<A>, marker::PhantomData<T>);
+
+impl<A: OpenAdapter<T::OpenData>, T: Operations> OperationsVtable<A, T> {
+    /// Called by the VFS when an inode should be opened.
+    ///
+    /// Calls `T::open` on the returned value of `A::convert`.
+    ///
+    /// # Safety
+    ///
+    /// The returned value of `A::convert` must be a valid non-null pointer and
+    /// `T:open` must return a valid non-null pointer on an `Ok` result.
+    unsafe extern "C" fn open_callback(
+        inode: *mut bindings::inode,
+        file: *mut bindings::file,
+    ) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: `A::convert` must return a valid non-null pointer that
+            // should point to data in the inode or file that lives longer
+            // than the following use of `T::open`.
+            let arg = unsafe { A::convert(inode, file) };
+            // SAFETY: The C contract guarantees that `file` is valid. Additionally,
+            // `fileref` never outlives this function, so it is guaranteed to be
+            // valid.
+            let fileref = unsafe { File::from_ptr(file) };
+            // SAFETY: `arg` was previously returned by `A::convert` and must
+            // be a valid non-null pointer.
+            let ptr = T::open(unsafe { &*arg }, fileref)?.into_pointer();
+            // SAFETY: The C contract guarantees that `private_data` is available
+            // for implementers of the file operations (no other C code accesses
+            // it), so we know that there are no concurrent threads/CPUs accessing
+            // it (it's not visible to any other Rust code).
+            unsafe { (*file).private_data = ptr as *mut core::ffi::c_void };
+            Ok(0)
+        }
+    }
+
+    unsafe extern "C" fn read_callback(
+        file: *mut bindings::file,
+        buf: *mut core::ffi::c_char,
+        len: core::ffi::c_size_t,
+        offset: *mut bindings::loff_t,
+    ) -> core::ffi::c_ssize_t {
+        from_kernel_result! {
+            let mut data =
+                unsafe { UserSlicePtr::new(buf as *mut core::ffi::c_void, len).writer() };
+            // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+            // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+            // `release` callback, which the C API guarantees that will be called only when all
+            // references to `file` have been released, so we know it can't be called while this
+            // function is running.
+            let f = unsafe { T::Data::borrow((*file).private_data) };
+            // No `FMODE_UNSIGNED_OFFSET` support, so `offset` must be in [0, 2^63).
+            // See <https://github.com/fishinabarrel/linux-kernel-module-rust/pull/113>.
+            let read = T::read(
+                f,
+                unsafe { File::from_ptr(file) },
+                &mut data,
+                unsafe { *offset }.try_into()?,
+            )?;
+            unsafe { (*offset) += bindings::loff_t::try_from(read).unwrap() };
+            Ok(read as _)
+        }
+    }
+
+    unsafe extern "C" fn read_iter_callback(
+        iocb: *mut bindings::kiocb,
+        raw_iter: *mut bindings::iov_iter,
+    ) -> isize {
+        from_kernel_result! {
+            let mut iter = unsafe { IovIter::from_ptr(raw_iter) };
+            let file = unsafe { (*iocb).ki_filp };
+            let offset = unsafe { (*iocb).ki_pos };
+            // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+            // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+            // `release` callback, which the C API guarantees that will be called only when all
+            // references to `file` have been released, so we know it can't be called while this
+            // function is running.
+            let f = unsafe { T::Data::borrow((*file).private_data) };
+            let read = T::read(
+                f,
+                unsafe { File::from_ptr(file) },
+                &mut iter,
+                offset.try_into()?,
+            )?;
+            unsafe { (*iocb).ki_pos += bindings::loff_t::try_from(read).unwrap() };
+            Ok(read as _)
+        }
+    }
+
+    unsafe extern "C" fn write_callback(
+        file: *mut bindings::file,
+        buf: *const core::ffi::c_char,
+        len: core::ffi::c_size_t,
+        offset: *mut bindings::loff_t,
+    ) -> core::ffi::c_ssize_t {
+        from_kernel_result! {
+            let mut data =
+                unsafe { UserSlicePtr::new(buf as *mut core::ffi::c_void, len).reader() };
+            // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+            // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+            // `release` callback, which the C API guarantees that will be called only when all
+            // references to `file` have been released, so we know it can't be called while this
+            // function is running.
+            let f = unsafe { T::Data::borrow((*file).private_data) };
+            // No `FMODE_UNSIGNED_OFFSET` support, so `offset` must be in [0, 2^63).
+            // See <https://github.com/fishinabarrel/linux-kernel-module-rust/pull/113>.
+            let written = T::write(
+                f,
+                unsafe { File::from_ptr(file) },
+                &mut data,
+                unsafe { *offset }.try_into()?,
+            )?;
+            unsafe { (*offset) += bindings::loff_t::try_from(written).unwrap() };
+            Ok(written as _)
+        }
+    }
+
+    unsafe extern "C" fn write_iter_callback(
+        iocb: *mut bindings::kiocb,
+        raw_iter: *mut bindings::iov_iter,
+    ) -> isize {
+        from_kernel_result! {
+            let mut iter = unsafe { IovIter::from_ptr(raw_iter) };
+            let file = unsafe { (*iocb).ki_filp };
+            let offset = unsafe { (*iocb).ki_pos };
+            // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+            // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+            // `release` callback, which the C API guarantees that will be called only when all
+            // references to `file` have been released, so we know it can't be called while this
+            // function is running.
+            let f = unsafe { T::Data::borrow((*file).private_data) };
+            let written = T::write(
+                f,
+                unsafe { File::from_ptr(file) },
+                &mut iter,
+                offset.try_into()?,
+            )?;
+            unsafe { (*iocb).ki_pos += bindings::loff_t::try_from(written).unwrap() };
+            Ok(written as _)
+        }
+    }
+
+    unsafe extern "C" fn release_callback(
+        _inode: *mut bindings::inode,
+        file: *mut bindings::file,
+    ) -> core::ffi::c_int {
+        let ptr = mem::replace(unsafe { &mut (*file).private_data }, ptr::null_mut());
+        T::release(unsafe { T::Data::from_pointer(ptr as _) }, unsafe {
+            File::from_ptr(file)
+        });
+        0
+    }
+
+    unsafe extern "C" fn llseek_callback(
+        file: *mut bindings::file,
+        offset: bindings::loff_t,
+        whence: core::ffi::c_int,
+    ) -> bindings::loff_t {
+        from_kernel_result! {
+            let off = match whence as u32 {
+                bindings::SEEK_SET => SeekFrom::Start(offset.try_into()?),
+                bindings::SEEK_CUR => SeekFrom::Current(offset),
+                bindings::SEEK_END => SeekFrom::End(offset),
+                _ => return Err(EINVAL),
+            };
+            // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+            // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+            // `release` callback, which the C API guarantees that will be called only when all
+            // references to `file` have been released, so we know it can't be called while this
+            // function is running.
+            let f = unsafe { T::Data::borrow((*file).private_data) };
+            let off = T::seek(f, unsafe { File::from_ptr(file) }, off)?;
+            Ok(off as bindings::loff_t)
+        }
+    }
+
+    unsafe extern "C" fn unlocked_ioctl_callback(
+        file: *mut bindings::file,
+        cmd: core::ffi::c_uint,
+        arg: core::ffi::c_ulong,
+    ) -> core::ffi::c_long {
+        from_kernel_result! {
+            // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+            // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+            // `release` callback, which the C API guarantees that will be called only when all
+            // references to `file` have been released, so we know it can't be called while this
+            // function is running.
+            let f = unsafe { T::Data::borrow((*file).private_data) };
+            let mut cmd = IoctlCommand::new(cmd as _, arg as _);
+            let ret = T::ioctl(f, unsafe { File::from_ptr(file) }, &mut cmd)?;
+            Ok(ret as _)
+        }
+    }
+
+    unsafe extern "C" fn compat_ioctl_callback(
+        file: *mut bindings::file,
+        cmd: core::ffi::c_uint,
+        arg: core::ffi::c_ulong,
+    ) -> core::ffi::c_long {
+        from_kernel_result! {
+            // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+            // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+            // `release` callback, which the C API guarantees that will be called only when all
+            // references to `file` have been released, so we know it can't be called while this
+            // function is running.
+            let f = unsafe { T::Data::borrow((*file).private_data) };
+            let mut cmd = IoctlCommand::new(cmd as _, arg as _);
+            let ret = T::compat_ioctl(f, unsafe { File::from_ptr(file) }, &mut cmd)?;
+            Ok(ret as _)
+        }
+    }
+
+    unsafe extern "C" fn mmap_callback(
+        file: *mut bindings::file,
+        vma: *mut bindings::vm_area_struct,
+    ) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+            // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+            // `release` callback, which the C API guarantees that will be called only when all
+            // references to `file` have been released, so we know it can't be called while this
+            // function is running.
+            let f = unsafe { T::Data::borrow((*file).private_data) };
+
+            // SAFETY: The C API guarantees that `vma` is valid for the duration of this call.
+            // `area` only lives within this call, so it is guaranteed to be valid.
+            let mut area = unsafe { mm::virt::Area::from_ptr(vma) };
+
+            // SAFETY: The C API guarantees that `file` is valid for the duration of this call,
+            // which is longer than the lifetime of the file reference.
+            T::mmap(f, unsafe { File::from_ptr(file) }, &mut area)?;
+            Ok(0)
+        }
+    }
+
+    unsafe extern "C" fn fsync_callback(
+        file: *mut bindings::file,
+        start: bindings::loff_t,
+        end: bindings::loff_t,
+        datasync: core::ffi::c_int,
+    ) -> core::ffi::c_int {
+        from_kernel_result! {
+            let start = start.try_into()?;
+            let end = end.try_into()?;
+            let datasync = datasync != 0;
+            // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+            // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the
+            // `release` callback, which the C API guarantees that will be called only when all
+            // references to `file` have been released, so we know it can't be called while this
+            // function is running.
+            let f = unsafe { T::Data::borrow((*file).private_data) };
+            let res = T::fsync(f, unsafe { File::from_ptr(file) }, start, end, datasync)?;
+            Ok(res.try_into().unwrap())
+        }
+    }
+
+    unsafe extern "C" fn poll_callback(
+        file: *mut bindings::file,
+        wait: *mut bindings::poll_table_struct,
+    ) -> bindings::__poll_t {
+        // SAFETY: `private_data` was initialised by `open_callback` with a value returned by
+        // `T::Data::into_pointer`. `T::Data::from_pointer` is only called by the `release`
+        // callback, which the C API guarantees that will be called only when all references to
+        // `file` have been released, so we know it can't be called while this function is running.
+        let f = unsafe { T::Data::borrow((*file).private_data) };
+        match T::poll(f, unsafe { File::from_ptr(file) }, unsafe {
+            &PollTable::from_ptr(wait)
+        }) {
+            Ok(v) => v,
+            Err(_) => bindings::POLLERR,
+        }
+    }
+
+    const VTABLE: bindings::file_operations = bindings::file_operations {
+        open: Some(Self::open_callback),
+        release: Some(Self::release_callback),
+        read: if T::HAS_READ {
+            Some(Self::read_callback)
+        } else {
+            None
+        },
+        write: if T::HAS_WRITE {
+            Some(Self::write_callback)
+        } else {
+            None
+        },
+        llseek: if T::HAS_SEEK {
+            Some(Self::llseek_callback)
+        } else {
+            None
+        },
+
+        check_flags: None,
+        compat_ioctl: if T::HAS_COMPAT_IOCTL {
+            Some(Self::compat_ioctl_callback)
+        } else {
+            None
+        },
+        copy_file_range: None,
+        fallocate: None,
+        fadvise: None,
+        fasync: None,
+        flock: None,
+        flush: None,
+        fsync: if T::HAS_FSYNC {
+            Some(Self::fsync_callback)
+        } else {
+            None
+        },
+        get_unmapped_area: None,
+        iterate: None,
+        iterate_shared: None,
+        iopoll: None,
+        lock: None,
+        mmap: if T::HAS_MMAP {
+            Some(Self::mmap_callback)
+        } else {
+            None
+        },
+        mmap_supported_flags: 0,
+        owner: ptr::null_mut(),
+        poll: if T::HAS_POLL {
+            Some(Self::poll_callback)
+        } else {
+            None
+        },
+        read_iter: if T::HAS_READ {
+            Some(Self::read_iter_callback)
+        } else {
+            None
+        },
+        remap_file_range: None,
+        sendpage: None,
+        setlease: None,
+        show_fdinfo: None,
+        splice_read: None,
+        splice_write: None,
+        unlocked_ioctl: if T::HAS_IOCTL {
+            Some(Self::unlocked_ioctl_callback)
+        } else {
+            None
+        },
+        uring_cmd: None,
+        write_iter: if T::HAS_WRITE {
+            Some(Self::write_iter_callback)
+        } else {
+            None
+        },
+    };
+
+    /// Builds an instance of [`struct file_operations`].
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that the adapter is compatible with the way the device is registered.
+    pub(crate) const unsafe fn build() -> &'static bindings::file_operations {
+        &Self::VTABLE
+    }
+}
+
+/// Allows the handling of ioctls defined with the `_IO`, `_IOR`, `_IOW`, and `_IOWR` macros.
+///
+/// For each macro, there is a handler function that takes the appropriate types as arguments.
+pub trait IoctlHandler: Sync {
+    /// The type of the first argument to each associated function.
+    type Target<'a>;
+
+    /// Handles ioctls defined with the `_IO` macro, that is, with no buffer as argument.
+    fn pure(_this: Self::Target<'_>, _file: &File, _cmd: u32, _arg: usize) -> Result<i32> {
+        Err(EINVAL)
+    }
+
+    /// Handles ioctls defined with the `_IOR` macro, that is, with an output buffer provided as
+    /// argument.
+    fn read(
+        _this: Self::Target<'_>,
+        _file: &File,
+        _cmd: u32,
+        _writer: &mut UserSlicePtrWriter,
+    ) -> Result<i32> {
+        Err(EINVAL)
+    }
+
+    /// Handles ioctls defined with the `_IOW` macro, that is, with an input buffer provided as
+    /// argument.
+    fn write(
+        _this: Self::Target<'_>,
+        _file: &File,
+        _cmd: u32,
+        _reader: &mut UserSlicePtrReader,
+    ) -> Result<i32> {
+        Err(EINVAL)
+    }
+
+    /// Handles ioctls defined with the `_IOWR` macro, that is, with a buffer for both input and
+    /// output provided as argument.
+    fn read_write(
+        _this: Self::Target<'_>,
+        _file: &File,
+        _cmd: u32,
+        _data: UserSlicePtr,
+    ) -> Result<i32> {
+        Err(EINVAL)
+    }
+}
+
+/// Represents an ioctl command.
+///
+/// It can use the components of an ioctl command to dispatch ioctls using
+/// [`IoctlCommand::dispatch`].
+pub struct IoctlCommand {
+    cmd: u32,
+    arg: usize,
+    user_slice: Option<UserSlicePtr>,
+}
+
+impl IoctlCommand {
+    /// Constructs a new [`IoctlCommand`].
+    fn new(cmd: u32, arg: usize) -> Self {
+        let size = (cmd >> bindings::_IOC_SIZESHIFT) & bindings::_IOC_SIZEMASK;
+
+        // SAFETY: We only create one instance of the user slice per ioctl call, so TOCTOU issues
+        // are not possible.
+        let user_slice = Some(unsafe { UserSlicePtr::new(arg as _, size as _) });
+        Self {
+            cmd,
+            arg,
+            user_slice,
+        }
+    }
+
+    /// Dispatches the given ioctl to the appropriate handler based on the value of the command. It
+    /// also creates a [`UserSlicePtr`], [`UserSlicePtrReader`], or [`UserSlicePtrWriter`]
+    /// depending on the direction of the buffer of the command.
+    ///
+    /// It is meant to be used in implementations of [`Operations::ioctl`] and
+    /// [`Operations::compat_ioctl`].
+    pub fn dispatch<T: IoctlHandler>(
+        &mut self,
+        handler: T::Target<'_>,
+        file: &File,
+    ) -> Result<i32> {
+        let dir = (self.cmd >> bindings::_IOC_DIRSHIFT) & bindings::_IOC_DIRMASK;
+        if dir == bindings::_IOC_NONE {
+            return T::pure(handler, file, self.cmd, self.arg);
+        }
+
+        let data = self.user_slice.take().ok_or(EINVAL)?;
+        const READ_WRITE: u32 = bindings::_IOC_READ | bindings::_IOC_WRITE;
+        match dir {
+            bindings::_IOC_WRITE => T::write(handler, file, self.cmd, &mut data.reader()),
+            bindings::_IOC_READ => T::read(handler, file, self.cmd, &mut data.writer()),
+            READ_WRITE => T::read_write(handler, file, self.cmd, data),
+            _ => Err(EINVAL),
+        }
+    }
+
+    /// Returns the raw 32-bit value of the command and the ptr-sized argument.
+    pub fn raw(&self) -> (u32, usize) {
+        (self.cmd, self.arg)
+    }
+}
+
+/// Trait for extracting file open arguments from kernel data structures.
+///
+/// This is meant to be implemented by registration managers.
+pub trait OpenAdapter<T: Sync> {
+    /// Converts untyped data stored in [`struct inode`] and [`struct file`] (when [`struct
+    /// file_operations::open`] is called) into the given type. For example, for `miscdev`
+    /// devices, a pointer to the registered [`struct miscdev`] is stored in [`struct
+    /// file::private_data`].
+    ///
+    /// # Safety
+    ///
+    /// This function must be called only when [`struct file_operations::open`] is being called for
+    /// a file that was registered by the implementer. The returned pointer must be valid and
+    /// not-null.
+    unsafe fn convert(_inode: *mut bindings::inode, _file: *mut bindings::file) -> *const T;
+}
+
+/// Corresponds to the kernel's `struct file_operations`.
+///
+/// You implement this trait whenever you would create a `struct file_operations`.
+///
+/// File descriptors may be used from multiple threads/processes concurrently, so your type must be
+/// [`Sync`]. It must also be [`Send`] because [`Operations::release`] will be called from the
+/// thread that decrements that associated file's refcount to zero.
+#[vtable]
+pub trait Operations {
+    /// The type of the context data returned by [`Operations::open`] and made available to
+    /// other methods.
+    type Data: PointerWrapper + Send + Sync = ();
+
+    /// The type of the context data passed to [`Operations::open`].
+    type OpenData: Sync = ();
+
+    /// Creates a new instance of this file.
+    ///
+    /// Corresponds to the `open` function pointer in `struct file_operations`.
+    fn open(context: &Self::OpenData, file: &File) -> Result<Self::Data>;
+
+    /// Cleans up after the last reference to the file goes away.
+    ///
+    /// Note that context data is moved, so it will be freed automatically unless the
+    /// implementation moves it elsewhere.
+    ///
+    /// Corresponds to the `release` function pointer in `struct file_operations`.
+    fn release(_data: Self::Data, _file: &File) {}
+
+    /// Reads data from this file to the caller's buffer.
+    ///
+    /// Corresponds to the `read` and `read_iter` function pointers in `struct file_operations`.
+    fn read(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _file: &File,
+        _writer: &mut impl IoBufferWriter,
+        _offset: u64,
+    ) -> Result<usize> {
+        Err(EINVAL)
+    }
+
+    /// Writes data from the caller's buffer to this file.
+    ///
+    /// Corresponds to the `write` and `write_iter` function pointers in `struct file_operations`.
+    fn write(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _file: &File,
+        _reader: &mut impl IoBufferReader,
+        _offset: u64,
+    ) -> Result<usize> {
+        Err(EINVAL)
+    }
+
+    /// Changes the position of the file.
+    ///
+    /// Corresponds to the `llseek` function pointer in `struct file_operations`.
+    fn seek(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _file: &File,
+        _offset: SeekFrom,
+    ) -> Result<u64> {
+        Err(EINVAL)
+    }
+
+    /// Performs IO control operations that are specific to the file.
+    ///
+    /// Corresponds to the `unlocked_ioctl` function pointer in `struct file_operations`.
+    fn ioctl(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _file: &File,
+        _cmd: &mut IoctlCommand,
+    ) -> Result<i32> {
+        Err(ENOTTY)
+    }
+
+    /// Performs 32-bit IO control operations on that are specific to the file on 64-bit kernels.
+    ///
+    /// Corresponds to the `compat_ioctl` function pointer in `struct file_operations`.
+    fn compat_ioctl(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _file: &File,
+        _cmd: &mut IoctlCommand,
+    ) -> Result<i32> {
+        Err(ENOTTY)
+    }
+
+    /// Syncs pending changes to this file.
+    ///
+    /// Corresponds to the `fsync` function pointer in `struct file_operations`.
+    fn fsync(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _file: &File,
+        _start: u64,
+        _end: u64,
+        _datasync: bool,
+    ) -> Result<u32> {
+        Err(EINVAL)
+    }
+
+    /// Maps areas of the caller's virtual memory with device/file memory.
+    ///
+    /// Corresponds to the `mmap` function pointer in `struct file_operations`.
+    fn mmap(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _file: &File,
+        _vma: &mut mm::virt::Area,
+    ) -> Result {
+        Err(EINVAL)
+    }
+
+    /// Checks the state of the file and optionally registers for notification when the state
+    /// changes.
+    ///
+    /// Corresponds to the `poll` function pointer in `struct file_operations`.
+    fn poll(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _file: &File,
+        _table: &PollTable,
+    ) -> Result<u32> {
+        Ok(bindings::POLLIN | bindings::POLLOUT | bindings::POLLRDNORM | bindings::POLLWRNORM)
+    }
+}
diff --git a/rust/kernel/fs.rs b/rust/kernel/fs.rs
new file mode 100644
index 000000000000..46dc38aad2bc
--- /dev/null
+++ b/rust/kernel/fs.rs
@@ -0,0 +1,846 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! File systems.
+//!
+//! C headers: [`include/linux/fs.h`](../../../../include/linux/fs.h)
+
+use crate::{
+    bindings, error::code::*, error::from_kernel_result, str::CStr, to_result,
+    types::PointerWrapper, AlwaysRefCounted, Error, Result, ScopeGuard, ThisModule,
+};
+use alloc::boxed::Box;
+use core::{
+    cell::UnsafeCell,
+    marker::{PhantomData, PhantomPinned},
+    pin::Pin,
+    ptr,
+};
+use macros::vtable;
+
+pub mod param;
+
+/// Type of superblock keying.
+///
+/// It determines how C's `fs_context_operations::get_tree` is implemented.
+pub enum Super {
+    /// Only one such superblock may exist.
+    Single,
+
+    /// As [`Super::Single`], but reconfigure if it exists.
+    SingleReconf,
+
+    /// Superblocks with different data pointers may exist.
+    Keyed,
+
+    /// Multiple independent superblocks may exist.
+    Independent,
+
+    /// Uses a block device.
+    BlockDev,
+}
+
+/// A file system context.
+///
+/// It is used to gather configuration to then mount or reconfigure a file system.
+#[vtable]
+pub trait Context<T: Type + ?Sized> {
+    /// Type of the data associated with the context.
+    type Data: PointerWrapper + Send + Sync + 'static;
+
+    /// The typed file system parameters.
+    ///
+    /// Users are encouraged to define it using the [`crate::define_fs_params`] macro.
+    const PARAMS: param::SpecTable<'static, Self::Data> = param::SpecTable::empty();
+
+    /// Creates a new context.
+    fn try_new() -> Result<Self::Data>;
+
+    /// Parses a parameter that wasn't specified in [`Self::PARAMS`].
+    fn parse_unknown_param(
+        _data: &mut Self::Data,
+        _name: &CStr,
+        _value: param::Value<'_>,
+    ) -> Result {
+        Err(ENOPARAM)
+    }
+
+    /// Parses the whole parameter block, potentially skipping regular handling for parts of it.
+    ///
+    /// The return value is the portion of the input buffer for which the regular handling
+    /// (involving [`Self::PARAMS`] and [`Self::parse_unknown_param`]) will still be carried out.
+    /// If it's `None`, the regular handling is not performed at all.
+    fn parse_monolithic<'a>(
+        _data: &mut Self::Data,
+        _buf: Option<&'a mut [u8]>,
+    ) -> Result<Option<&'a mut [u8]>> {
+        Ok(None)
+    }
+
+    /// Returns the superblock data to be used by this file system context.
+    ///
+    /// This is only needed when [`Type::SUPER_TYPE`] is [`Super::Keyed`], otherwise it is never
+    /// called. In the former case, when the fs is being mounted, an existing superblock is reused
+    /// if one can be found with the same data as the returned value; otherwise a new superblock is
+    /// created.
+    fn tree_key(_data: &mut Self::Data) -> Result<T::Data> {
+        Err(ENOTSUPP)
+    }
+}
+
+struct Tables<T: Type + ?Sized>(T);
+impl<T: Type + ?Sized> Tables<T> {
+    const CONTEXT: bindings::fs_context_operations = bindings::fs_context_operations {
+        free: Some(Self::free_callback),
+        parse_param: Some(Self::parse_param_callback),
+        get_tree: Some(Self::get_tree_callback),
+        reconfigure: Some(Self::reconfigure_callback),
+        parse_monolithic: if <T::Context as Context<T>>::HAS_PARSE_MONOLITHIC {
+            Some(Self::parse_monolithic_callback)
+        } else {
+            None
+        },
+        dup: None,
+    };
+
+    unsafe extern "C" fn free_callback(fc: *mut bindings::fs_context) {
+        // SAFETY: The callback contract guarantees that `fc` is valid.
+        let fc = unsafe { &*fc };
+
+        let ptr = fc.fs_private;
+        if !ptr.is_null() {
+            // SAFETY: `fs_private` was initialised with the result of a `to_pointer` call in
+            // `init_fs_context_callback`, so it's ok to call `from_pointer` here.
+            unsafe { <T::Context as Context<T>>::Data::from_pointer(ptr) };
+        }
+
+        let ptr = fc.s_fs_info;
+        if !ptr.is_null() {
+            // SAFETY: `s_fs_info` may be initialised with the result of a `to_pointer` call in
+            // `get_tree_callback` when keyed superblocks are used (`get_tree_keyed` sets it), so
+            // it's ok to call `from_pointer` here.
+            unsafe { T::Data::from_pointer(ptr) };
+        }
+    }
+
+    unsafe extern "C" fn parse_param_callback(
+        fc: *mut bindings::fs_context,
+        param: *mut bindings::fs_parameter,
+    ) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: The callback contract guarantees that `fc` is valid.
+            let ptr = unsafe { (*fc).fs_private };
+
+            // SAFETY: The value of `ptr` (coming from `fs_private` was initialised in
+            // `init_fs_context_callback` to the result of an `into_pointer` call. Since the
+            // context is valid, `from_pointer` wasn't called yet, so `ptr` is valid. Additionally,
+            // the callback contract guarantees that callbacks are serialised, so it is ok to
+            // mutably reference it.
+            let mut data =
+                unsafe { <<T::Context as Context<T>>::Data as PointerWrapper>::borrow_mut(ptr) };
+            let mut result = bindings::fs_parse_result::default();
+            // SAFETY: All parameters are valid at least for the duration of the call.
+            let opt =
+                unsafe { bindings::fs_parse(fc, T::Context::PARAMS.first, param, &mut result) };
+
+            // SAFETY: The callback contract guarantees that `param` is valid for the duration of
+            // the callback.
+            let param = unsafe { &*param };
+            if opt >= 0 {
+                let opt = opt as usize;
+                if opt >= T::Context::PARAMS.handlers.len() {
+                    return Err(EINVAL);
+                }
+                T::Context::PARAMS.handlers[opt].handle_param(&mut data, param, &result)?;
+                return Ok(0);
+            }
+
+            if opt != ENOPARAM.to_kernel_errno() {
+                return Err(Error::from_kernel_errno(opt));
+            }
+
+            if !T::Context::HAS_PARSE_UNKNOWN_PARAM {
+                return Err(ENOPARAM);
+            }
+
+            let val = param::Value::from_fs_parameter(param);
+            // SAFETY: The callback contract guarantees the parameter key to be valid and last at
+            // least the duration of the callback.
+            T::Context::parse_unknown_param(
+                &mut data,
+                unsafe { CStr::from_char_ptr(param.key) },
+                val,
+            )?;
+            Ok(0)
+        }
+    }
+
+    unsafe extern "C" fn fill_super_callback(
+        sb_ptr: *mut bindings::super_block,
+        fc: *mut bindings::fs_context,
+    ) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: The callback contract guarantees that `fc` is valid. It also guarantees that
+            // the callbacks are serialised for a given `fc`, so it is safe to mutably dereference
+            // it.
+            let fc = unsafe { &mut *fc };
+            let ptr = core::mem::replace(&mut fc.fs_private, ptr::null_mut());
+
+            // SAFETY: The value of `ptr` (coming from `fs_private` was initialised in
+            // `init_fs_context_callback` to the result of an `into_pointer` call. The context is
+            // being used to initialise a superblock, so we took over `ptr` (`fs_private` is set to
+            // null now) and call `from_pointer` below.
+            let data =
+                unsafe { <<T::Context as Context<T>>::Data as PointerWrapper>::from_pointer(ptr) };
+
+            // SAFETY: The callback contract guarantees that `sb_ptr` is a unique pointer to a
+            // newly-created superblock.
+            let newsb = unsafe { NewSuperBlock::new(sb_ptr) };
+            T::fill_super(data, newsb)?;
+            Ok(0)
+        }
+    }
+
+    unsafe extern "C" fn get_tree_callback(fc: *mut bindings::fs_context) -> core::ffi::c_int {
+        // N.B. When new types are added below, we may need to update `kill_sb_callback` to ensure
+        // that we're cleaning up properly.
+        match T::SUPER_TYPE {
+            Super::Single => unsafe {
+                // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also has
+                // the right type and is a valid callback.
+                bindings::get_tree_single(fc, Some(Self::fill_super_callback))
+            },
+            Super::SingleReconf => unsafe {
+                // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also has
+                // the right type and is a valid callback.
+                bindings::get_tree_single_reconf(fc, Some(Self::fill_super_callback))
+            },
+            Super::Independent => unsafe {
+                // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also has
+                // the right type and is a valid callback.
+                bindings::get_tree_nodev(fc, Some(Self::fill_super_callback))
+            },
+            Super::BlockDev => unsafe {
+                // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also has
+                // the right type and is a valid callback.
+                bindings::get_tree_bdev(fc, Some(Self::fill_super_callback))
+            },
+            Super::Keyed => {
+                from_kernel_result! {
+                    // SAFETY: `fc` is valid per the callback contract.
+                    let ctx = unsafe { &*fc };
+                    let ptr = ctx.fs_private;
+
+                    // SAFETY: The value of `ptr` (coming from `fs_private` was initialised in
+                    // `init_fs_context_callback` to the result of an `into_pointer` call. Since
+                    // the context is valid, `from_pointer` wasn't called yet, so `ptr` is valid.
+                    // Additionally, the callback contract guarantees that callbacks are
+                    // serialised, so it is ok to mutably reference it.
+                    let mut data = unsafe {
+                        <<T::Context as Context<T>>::Data as PointerWrapper>::borrow_mut(ptr)
+                    };
+                    let fs_data = T::Context::tree_key(&mut data)?;
+                    let fs_data_ptr = fs_data.into_pointer();
+
+                    // `get_tree_keyed` reassigns `ctx.s_fs_info`, which should be ok because
+                    // nowhere else is it assigned a non-null value. However, we add the assert
+                    // below to ensure that there are no unexpected paths on the C side that may do
+                    // this.
+                    assert_eq!(ctx.s_fs_info, core::ptr::null_mut());
+
+                    // SAFETY: `fc` is valid per the callback contract. `fill_super_callback` also
+                    // has the right type and is a valid callback. Lastly, we just called
+                    // `into_pointer` above, so `fs_data_ptr` is also valid.
+                    to_result(unsafe {
+                        bindings::get_tree_keyed(
+                            fc,
+                            Some(Self::fill_super_callback),
+                            fs_data_ptr as _,
+                        )
+                    })?;
+                    Ok(0)
+                }
+            }
+        }
+    }
+
+    unsafe extern "C" fn reconfigure_callback(_fc: *mut bindings::fs_context) -> core::ffi::c_int {
+        EINVAL.to_kernel_errno()
+    }
+
+    unsafe extern "C" fn parse_monolithic_callback(
+        fc: *mut bindings::fs_context,
+        buf: *mut core::ffi::c_void,
+    ) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: The callback contract guarantees that `fc` is valid.
+            let ptr = unsafe { (*fc).fs_private };
+
+            // SAFETY: The value of `ptr` (coming from `fs_private` was initialised in
+            // `init_fs_context_callback` to the result of an `into_pointer` call. Since the
+            // context is valid, `from_pointer` wasn't called yet, so `ptr` is valid. Additionally,
+            // the callback contract guarantees that callbacks are serialised, so it is ok to
+            // mutably reference it.
+            let mut data =
+                unsafe { <<T::Context as Context<T>>::Data as PointerWrapper>::borrow_mut(ptr) };
+            let page = if buf.is_null() {
+                None
+            } else {
+                // SAFETY: This callback is called to handle the `mount` syscall, which takes a
+                // page-sized buffer as data.
+                Some(unsafe { &mut *ptr::slice_from_raw_parts_mut(buf.cast(), crate::PAGE_SIZE) })
+            };
+            let regular = T::Context::parse_monolithic(&mut data, page)?;
+            if let Some(buf) = regular {
+                // SAFETY: Both `fc` and `buf` are guaranteed to be valid; the former because the
+                // callback is still ongoing and the latter because its lifefime is tied to that of
+                // `page`, which is also valid for the duration of the callback.
+                to_result(unsafe {
+                    bindings::generic_parse_monolithic(fc, buf.as_mut_ptr().cast())
+                })?;
+            }
+            Ok(0)
+        }
+    }
+
+    const SUPER_BLOCK: bindings::super_operations = bindings::super_operations {
+        alloc_inode: None,
+        destroy_inode: None,
+        free_inode: None,
+        dirty_inode: None,
+        write_inode: None,
+        drop_inode: None,
+        evict_inode: None,
+        put_super: None,
+        sync_fs: None,
+        freeze_super: None,
+        freeze_fs: None,
+        thaw_super: None,
+        unfreeze_fs: None,
+        statfs: None,
+        remount_fs: None,
+        umount_begin: None,
+        show_options: None,
+        show_devname: None,
+        show_path: None,
+        show_stats: None,
+        #[cfg(CONFIG_QUOTA)]
+        quota_read: None,
+        #[cfg(CONFIG_QUOTA)]
+        quota_write: None,
+        #[cfg(CONFIG_QUOTA)]
+        get_dquots: None,
+        nr_cached_objects: None,
+        free_cached_objects: None,
+    };
+}
+
+/// A file system type.
+pub trait Type {
+    /// The context used to build fs configuration before it is mounted or reconfigured.
+    type Context: Context<Self> + ?Sized;
+
+    /// Data associated with each file system instance.
+    type Data: PointerWrapper + Send + Sync = ();
+
+    /// Determines how superblocks for this file system type are keyed.
+    const SUPER_TYPE: Super;
+
+    /// The name of the file system type.
+    const NAME: &'static CStr;
+
+    /// The flags of this file system type.
+    ///
+    /// It is a combination of the flags in the [`flags`] module.
+    const FLAGS: i32;
+
+    /// Initialises a super block for this file system type.
+    fn fill_super(
+        data: <Self::Context as Context<Self>>::Data,
+        sb: NewSuperBlock<'_, Self>,
+    ) -> Result<&SuperBlock<Self>>;
+}
+
+/// File system flags.
+pub mod flags {
+    use crate::bindings;
+
+    /// The file system requires a device.
+    pub const REQUIRES_DEV: i32 = bindings::FS_REQUIRES_DEV as _;
+
+    /// The options provided when mounting are in binary form.
+    pub const BINARY_MOUNTDATA: i32 = bindings::FS_BINARY_MOUNTDATA as _;
+
+    /// The file system has a subtype. It is extracted from the name and passed in as a parameter.
+    pub const HAS_SUBTYPE: i32 = bindings::FS_HAS_SUBTYPE as _;
+
+    /// The file system can be mounted by userns root.
+    pub const USERNS_MOUNT: i32 = bindings::FS_USERNS_MOUNT as _;
+
+    /// Disables fanotify permission events.
+    pub const DISALLOW_NOTIFY_PERM: i32 = bindings::FS_DISALLOW_NOTIFY_PERM as _;
+
+    /// The file system has been updated to handle vfs idmappings.
+    pub const ALLOW_IDMAP: i32 = bindings::FS_ALLOW_IDMAP as _;
+
+    /// The file systen will handle `d_move` during `rename` internally.
+    pub const RENAME_DOES_D_MOVE: i32 = bindings::FS_RENAME_DOES_D_MOVE as _;
+}
+
+/// A file system registration.
+#[derive(Default)]
+pub struct Registration {
+    is_registered: bool,
+    fs: UnsafeCell<bindings::file_system_type>,
+    _pin: PhantomPinned,
+}
+
+// SAFETY: `Registration` doesn't really provide any `&self` methods, so it is safe to pass
+// references to it around.
+unsafe impl Sync for Registration {}
+
+// SAFETY: Both registration and unregistration are implemented in C and safe to be performed from
+// any thread, so `Registration` is `Send`.
+unsafe impl Send for Registration {}
+
+impl Registration {
+    /// Creates a new file system registration.
+    ///
+    /// It is not visible or accessible yet. A successful call to [`Registration::register`] needs
+    /// to be made before users can mount it.
+    pub fn new() -> Self {
+        Self {
+            is_registered: false,
+            fs: UnsafeCell::new(bindings::file_system_type::default()),
+            _pin: PhantomPinned,
+        }
+    }
+
+    /// Registers a file system so that it can be mounted by users.
+    ///
+    /// The file system is described by the [`Type`] argument.
+    ///
+    /// It is automatically unregistered when the registration is dropped.
+    pub fn register<T: Type + ?Sized>(self: Pin<&mut Self>, module: &'static ThisModule) -> Result {
+        // SAFETY: We never move out of `this`.
+        let this = unsafe { self.get_unchecked_mut() };
+
+        if this.is_registered {
+            return Err(EINVAL);
+        }
+
+        let mut fs = this.fs.get_mut();
+        fs.owner = module.0;
+        fs.name = T::NAME.as_char_ptr();
+        fs.fs_flags = T::FLAGS;
+        fs.parameters = T::Context::PARAMS.first;
+        fs.init_fs_context = Some(Self::init_fs_context_callback::<T>);
+        fs.kill_sb = Some(Self::kill_sb_callback::<T>);
+
+        // SAFETY: This block registers all fs type keys with lockdep. We just need the memory
+        // locations to be owned by the caller, which is the case.
+        unsafe {
+            bindings::lockdep_register_key(&mut fs.s_lock_key);
+            bindings::lockdep_register_key(&mut fs.s_umount_key);
+            bindings::lockdep_register_key(&mut fs.s_vfs_rename_key);
+            bindings::lockdep_register_key(&mut fs.i_lock_key);
+            bindings::lockdep_register_key(&mut fs.i_mutex_key);
+            bindings::lockdep_register_key(&mut fs.invalidate_lock_key);
+            bindings::lockdep_register_key(&mut fs.i_mutex_dir_key);
+            for key in &mut fs.s_writers_key {
+                bindings::lockdep_register_key(key);
+            }
+        }
+
+        let ptr = this.fs.get();
+
+        // SAFETY: `ptr` as valid as it points to the `self.fs`.
+        let key_guard = ScopeGuard::new(|| unsafe { Self::unregister_keys(ptr) });
+
+        // SAFETY: Pointers stored in `fs` are either static so will live for as long as the
+        // registration is active (it is undone in `drop`).
+        to_result(unsafe { bindings::register_filesystem(ptr) })?;
+        key_guard.dismiss();
+        this.is_registered = true;
+        Ok(())
+    }
+
+    /// Unregisters the lockdep keys in the file system type.
+    ///
+    /// # Safety
+    ///
+    /// `fs` must be non-null and valid.
+    unsafe fn unregister_keys(fs: *mut bindings::file_system_type) {
+        // SAFETY: This block unregisters all fs type keys from lockdep. They must have been
+        // registered before.
+        unsafe {
+            bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).s_lock_key));
+            bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).s_umount_key));
+            bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).s_vfs_rename_key));
+            bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).i_lock_key));
+            bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).i_mutex_key));
+            bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).invalidate_lock_key));
+            bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).i_mutex_dir_key));
+            for i in 0..(*fs).s_writers_key.len() {
+                bindings::lockdep_unregister_key(ptr::addr_of_mut!((*fs).s_writers_key[i]));
+            }
+        }
+    }
+
+    unsafe extern "C" fn init_fs_context_callback<T: Type + ?Sized>(
+        fc_ptr: *mut bindings::fs_context,
+    ) -> core::ffi::c_int {
+        from_kernel_result! {
+            let data = T::Context::try_new()?;
+            // SAFETY: The callback contract guarantees that `fc_ptr` is the only pointer to a
+            // newly-allocated fs context, so it is safe to mutably reference it.
+            let fc = unsafe { &mut *fc_ptr };
+            fc.fs_private = data.into_pointer() as _;
+            fc.ops = &Tables::<T>::CONTEXT;
+            Ok(0)
+        }
+    }
+
+    unsafe extern "C" fn kill_sb_callback<T: Type + ?Sized>(sb_ptr: *mut bindings::super_block) {
+        if let Super::BlockDev = T::SUPER_TYPE {
+            // SAFETY: When the superblock type is `BlockDev`, we have a block device so it's safe
+            // to call `kill_block_super`. Additionally, the callback contract guarantees that
+            // `sb_ptr` is valid.
+            unsafe { bindings::kill_block_super(sb_ptr) }
+        } else {
+            // SAFETY: We always call a `get_tree_nodev` variant from `get_tree_callback` without a
+            // device when `T::SUPER_TYPE` is not `BlockDev`, so we never have a device in such
+            // cases, therefore it is ok to call the function below. Additionally, the callback
+            // contract guarantees that `sb_ptr` is valid.
+            unsafe { bindings::kill_anon_super(sb_ptr) }
+        }
+
+        // SAFETY: The callback contract guarantees that `sb_ptr` is valid.
+        let sb = unsafe { &*sb_ptr };
+
+        // SAFETY: The `kill_sb` callback being called implies that the `s_type` field is valid.
+        unsafe { Self::unregister_keys(sb.s_type) };
+
+        let ptr = sb.s_fs_info;
+        if !ptr.is_null() {
+            // SAFETY: The only place where `s_fs_info` is assigned is `NewSuperBlock::init`, where
+            // it's initialised with the result of a `to_pointer` call. We checked above that ptr
+            // is non-null because it would be null if we never reached the point where we init the
+            // field.
+            unsafe { T::Data::from_pointer(ptr) };
+        }
+    }
+}
+
+impl Drop for Registration {
+    fn drop(&mut self) {
+        if self.is_registered {
+            // SAFETY: When `is_registered` is `true`, a previous call to `register_filesystem` has
+            // succeeded, so it is safe to unregister here.
+            unsafe { bindings::unregister_filesystem(self.fs.get()) };
+        }
+    }
+}
+
+/// State of [`NewSuperBlock`] that indicates that [`NewSuperBlock::init`] needs to be called
+/// eventually.
+pub struct NeedsInit;
+
+/// State of [`NewSuperBlock`] that indicates that [`NewSuperBlock::init_root`] needs to be called
+/// eventually.
+pub struct NeedsRoot;
+
+/// Required superblock parameters.
+///
+/// This is used in [`NewSuperBlock::init`].
+pub struct SuperParams {
+    /// The magic number of the superblock.
+    pub magic: u32,
+
+    /// The size of a block in powers of 2 (i.e., for a value of `n`, the size is `2^n`.
+    pub blocksize_bits: u8,
+
+    /// Maximum size of a file.
+    pub maxbytes: i64,
+
+    /// Granularity of c/m/atime in ns (cannot be worse than a second).
+    pub time_gran: u32,
+}
+
+impl SuperParams {
+    /// Default value for instances of [`SuperParams`].
+    pub const DEFAULT: Self = Self {
+        magic: 0,
+        blocksize_bits: crate::PAGE_SIZE as _,
+        maxbytes: bindings::MAX_LFS_FILESIZE,
+        time_gran: 1,
+    };
+}
+
+/// A superblock that is still being initialised.
+///
+/// It uses type states to ensure that callers use the right sequence of calls.
+///
+/// # Invariants
+///
+/// The superblock is a newly-created one and this is the only active pointer to it.
+pub struct NewSuperBlock<'a, T: Type + ?Sized, S = NeedsInit> {
+    sb: *mut bindings::super_block,
+    _p: PhantomData<(&'a T, S)>,
+}
+
+impl<'a, T: Type + ?Sized> NewSuperBlock<'a, T, NeedsInit> {
+    /// Creates a new instance of [`NewSuperBlock`].
+    ///
+    /// # Safety
+    ///
+    /// `sb` must point to a newly-created superblock and it must be the only active pointer to it.
+    unsafe fn new(sb: *mut bindings::super_block) -> Self {
+        // INVARIANT: The invariants are satisfied by the safety requirements of this function.
+        Self {
+            sb,
+            _p: PhantomData,
+        }
+    }
+
+    /// Initialises the superblock so that it transitions to the [`NeedsRoot`] type state.
+    pub fn init(
+        self,
+        data: T::Data,
+        params: &SuperParams,
+    ) -> Result<NewSuperBlock<'a, T, NeedsRoot>> {
+        // SAFETY: The type invariant guarantees that `self.sb` is the only pointer to a
+        // newly-allocated superblock, so it is safe to mutably reference it.
+        let sb = unsafe { &mut *self.sb };
+
+        sb.s_magic = params.magic as _;
+        sb.s_op = &Tables::<T>::SUPER_BLOCK;
+        sb.s_maxbytes = params.maxbytes;
+        sb.s_time_gran = params.time_gran;
+        sb.s_blocksize_bits = params.blocksize_bits;
+        sb.s_blocksize = 1;
+        if sb.s_blocksize.leading_zeros() < params.blocksize_bits.into() {
+            return Err(EINVAL);
+        }
+        sb.s_blocksize = 1 << sb.s_blocksize_bits;
+
+        // Keyed file systems already have `s_fs_info` initialised.
+        let info = data.into_pointer() as *mut _;
+        if let Super::Keyed = T::SUPER_TYPE {
+            // SAFETY: We just called `into_pointer` above.
+            unsafe { T::Data::from_pointer(info) };
+
+            if sb.s_fs_info != info {
+                return Err(EINVAL);
+            }
+        } else {
+            sb.s_fs_info = info;
+        }
+
+        Ok(NewSuperBlock {
+            sb: self.sb,
+            _p: PhantomData,
+        })
+    }
+}
+
+impl<'a, T: Type + ?Sized> NewSuperBlock<'a, T, NeedsRoot> {
+    /// Initialises the root of the superblock.
+    pub fn init_root(self) -> Result<&'a SuperBlock<T>> {
+        // The following is temporary code to create the root inode and dentry. It will be replaced
+        // once we allow inodes and dentries to be created directly from Rust code.
+
+        // SAFETY: `sb` is initialised (`NeedsRoot` typestate implies it), so it is safe to pass it
+        // to `new_inode`.
+        let inode = unsafe { bindings::new_inode(self.sb) };
+        if inode.is_null() {
+            return Err(ENOMEM);
+        }
+
+        {
+            // SAFETY: This is a newly-created inode. No other references to it exist, so it is
+            // safe to mutably dereference it.
+            let inode = unsafe { &mut *inode };
+
+            // SAFETY: `current_time` requires that `inode.sb` be valid, which is the case here
+            // since we allocated the inode through the superblock.
+            let time = unsafe { bindings::current_time(inode) };
+            inode.i_ino = 1;
+            inode.i_mode = (bindings::S_IFDIR | 0o755) as _;
+            inode.i_mtime = time;
+            inode.i_atime = time;
+            inode.i_ctime = time;
+
+            // SAFETY: `simple_dir_operations` never changes, it's safe to reference it.
+            inode.__bindgen_anon_3.i_fop = unsafe { &bindings::simple_dir_operations };
+
+            // SAFETY: `simple_dir_inode_operations` never changes, it's safe to reference it.
+            inode.i_op = unsafe { &bindings::simple_dir_inode_operations };
+
+            // SAFETY: `inode` is valid for write.
+            unsafe { bindings::set_nlink(inode, 2) };
+        }
+
+        // SAFETY: `d_make_root` requires that `inode` be valid and referenced, which is the
+        // case for this call.
+        //
+        // It takes over the inode, even on failure, so we don't need to clean it up.
+        let dentry = unsafe { bindings::d_make_root(inode) };
+        if dentry.is_null() {
+            return Err(ENOMEM);
+        }
+
+        // SAFETY: The typestate guarantees that `self.sb` is valid.
+        unsafe { (*self.sb).s_root = dentry };
+
+        // SAFETY: The typestate guarantees that `self.sb` is initialised and we just finished
+        // setting its root, so it's a fully ready superblock.
+        Ok(unsafe { &mut *self.sb.cast() })
+    }
+}
+
+/// A file system super block.
+///
+/// Wraps the kernel's `struct super_block`.
+#[repr(transparent)]
+pub struct SuperBlock<T: Type + ?Sized>(
+    pub(crate) UnsafeCell<bindings::super_block>,
+    PhantomData<T>,
+);
+
+/// Wraps the kernel's `struct inode`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `ihold` ensures that the
+/// allocation remains valid at least until the matching call to `iput`.
+#[repr(transparent)]
+pub struct INode(pub(crate) UnsafeCell<bindings::inode>);
+
+// SAFETY: The type invariants guarantee that `INode` is always ref-counted.
+unsafe impl AlwaysRefCounted for INode {
+    fn inc_ref(&self) {
+        // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+        unsafe { bindings::ihold(self.0.get()) };
+    }
+
+    unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
+        // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+        unsafe { bindings::iput(obj.cast().as_ptr()) }
+    }
+}
+
+/// Wraps the kernel's `struct dentry`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `dget` ensures that the
+/// allocation remains valid at least until the matching call to `dput`.
+#[repr(transparent)]
+pub struct DEntry(pub(crate) UnsafeCell<bindings::dentry>);
+
+// SAFETY: The type invariants guarantee that `DEntry` is always ref-counted.
+unsafe impl AlwaysRefCounted for DEntry {
+    fn inc_ref(&self) {
+        // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+        unsafe { bindings::dget(self.0.get()) };
+    }
+
+    unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
+        // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+        unsafe { bindings::dput(obj.cast().as_ptr()) }
+    }
+}
+
+/// Wraps the kernel's `struct filename`.
+#[repr(transparent)]
+pub struct Filename(pub(crate) UnsafeCell<bindings::filename>);
+
+impl Filename {
+    /// Creates a reference to a [`Filename`] from a valid pointer.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
+    /// returned [`Filename`] instance.
+    pub(crate) unsafe fn from_ptr<'a>(ptr: *const bindings::filename) -> &'a Filename {
+        // SAFETY: The safety requirements guarantee the validity of the dereference, while the
+        // `Filename` type being transparent makes the cast ok.
+        unsafe { &*ptr.cast() }
+    }
+}
+
+/// Kernel module that exposes a single file system implemented by `T`.
+pub struct Module<T: Type> {
+    _fs: Pin<Box<Registration>>,
+    _p: PhantomData<T>,
+}
+
+impl<T: Type + Sync> crate::Module for Module<T> {
+    fn init(_name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+        let mut reg = Pin::from(Box::try_new(Registration::new())?);
+        reg.as_mut().register::<T>(module)?;
+        Ok(Self {
+            _fs: reg,
+            _p: PhantomData,
+        })
+    }
+}
+
+/// Declares a kernel module that exposes a single file system.
+///
+/// The `type` argument must be a type which implements the [`Type`] trait. Also accepts various
+/// forms of kernel metadata.
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::prelude::*;
+/// use kernel::{c_str, fs};
+///
+/// module_fs! {
+///     type: MyFs,
+///     name: b"my_fs_kernel_module",
+///     author: b"Rust for Linux Contributors",
+///     description: b"My very own file system kernel module!",
+///     license: b"GPL",
+/// }
+///
+/// struct MyFs;
+///
+/// #[vtable]
+/// impl fs::Context<Self> for MyFs {
+///     type Data = ();
+///     fn try_new() -> Result {
+///         Ok(())
+///     }
+/// }
+///
+/// impl fs::Type for MyFs {
+///     type Context = Self;
+///     const SUPER_TYPE: fs::Super = fs::Super::Independent;
+///     const NAME: &'static CStr = c_str!("example");
+///     const FLAGS: i32 = 0;
+///
+///     fn fill_super(_data: (), sb: fs::NewSuperBlock<'_, Self>) -> Result<&fs::SuperBlock<Self>> {
+///         let sb = sb.init(
+///             (),
+///             &fs::SuperParams {
+///                 magic: 0x6578616d,
+///                 ..fs::SuperParams::DEFAULT
+///             },
+///         )?;
+///         let sb = sb.init_root()?;
+///         Ok(sb)
+///     }
+/// }
+/// ```
+#[macro_export]
+macro_rules! module_fs {
+    (type: $type:ty, $($f:tt)*) => {
+        type ModuleType = $crate::fs::Module<$type>;
+        $crate::macros::module! {
+            type: ModuleType,
+            $($f)*
+        }
+    }
+}
diff --git a/rust/kernel/fs/param.rs b/rust/kernel/fs/param.rs
new file mode 100644
index 000000000000..445cea404bcd
--- /dev/null
+++ b/rust/kernel/fs/param.rs
@@ -0,0 +1,553 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! File system parameters and parsing them.
+//!
+//! C headers: [`include/linux/fs_parser.h`](../../../../../include/linux/fs_parser.h)
+
+use crate::{bindings, file, fs, str::CStr, Result};
+use core::{marker::PhantomData, ptr};
+
+/// The value of a file system parameter.
+pub enum Value<'a> {
+    /// The value is undefined.
+    Undefined,
+
+    /// There is no value, but parameter itself is a flag.
+    Flag,
+
+    /// The value is the given string.
+    String(&'a CStr),
+
+    /// The value is the given binary blob.
+    Blob(&'a mut [u8]),
+
+    /// The value is the given file.
+    File(&'a file::File),
+
+    /// The value is the given filename and the given directory file descriptor (which may be
+    /// `AT_FDCWD`, to indicate the current directory).
+    Filename(&'a fs::Filename, i32),
+}
+
+impl<'a> Value<'a> {
+    pub(super) fn from_fs_parameter(p: &'a bindings::fs_parameter) -> Self {
+        match p.type_() {
+            bindings::fs_value_type_fs_value_is_string => {
+                // SAFETY: `type_` is string, so it is ok to use the union field. Additionally, it
+                // is guaranteed to be valid while `p` is valid.
+                Self::String(unsafe { CStr::from_char_ptr(p.__bindgen_anon_1.string) })
+            }
+            bindings::fs_value_type_fs_value_is_flag => Self::Flag,
+            bindings::fs_value_type_fs_value_is_blob => {
+                // SAFETY: `type_` is blob, so it is ok to use the union field and size.
+                // Additionally, it is guaranteed to be valid while `p` is valid.
+                let slice = unsafe {
+                    &mut *ptr::slice_from_raw_parts_mut(p.__bindgen_anon_1.blob.cast(), p.size)
+                };
+                Self::Blob(slice)
+            }
+            bindings::fs_value_type_fs_value_is_file => {
+                // SAFETY: `type_` is file, so it is ok to use the union field. Additionally, it is
+                // guaranteed to be valid while `p` is valid.
+                let file_ptr = unsafe { p.__bindgen_anon_1.file };
+                if file_ptr.is_null() {
+                    Self::Undefined
+                } else {
+                    // SAFETY: `file_ptr` is non-null and guaranteed to be valid while `p` is.
+                    Self::File(unsafe { file::File::from_ptr(file_ptr) })
+                }
+            }
+            bindings::fs_value_type_fs_value_is_filename => {
+                // SAFETY: `type_` is filename, so it is ok to use the union field. Additionally,
+                // it is guaranteed to be valid while `p` is valid.
+                let filename_ptr = unsafe { p.__bindgen_anon_1.name };
+                if filename_ptr.is_null() {
+                    Self::Undefined
+                } else {
+                    // SAFETY: `filename_ptr` is non-null and guaranteed to be valid while `p` is.
+                    Self::Filename(unsafe { fs::Filename::from_ptr(filename_ptr) }, p.dirfd)
+                }
+            }
+            _ => Self::Undefined,
+        }
+    }
+}
+
+/// A specification of a file system parameter.
+pub struct Spec {
+    name: &'static CStr,
+    flags: u16,
+    type_: bindings::fs_param_type,
+    extra: *const core::ffi::c_void,
+}
+
+const DEFAULT: Spec = Spec {
+    name: crate::c_str!(""),
+    flags: 0,
+    type_: None,
+    extra: core::ptr::null(),
+};
+
+macro_rules! define_param_type {
+    ($name:ident, $fntype:ty, $spec:expr, |$param:ident, $result:ident| $value:expr) => {
+        /// Module to support `$name` parameter types.
+        pub mod $name {
+            use super::*;
+
+            #[doc(hidden)]
+            pub const fn spec(name: &'static CStr) -> Spec {
+                const GIVEN: Spec = $spec;
+                Spec { name, ..GIVEN }
+            }
+
+            #[doc(hidden)]
+            pub const fn handler<S>(setfn: fn(&mut S, $fntype) -> Result) -> impl Handler<S> {
+                let c =
+                    move |s: &mut S,
+                          $param: &bindings::fs_parameter,
+                          $result: &bindings::fs_parse_result| { setfn(s, $value) };
+                ConcreteHandler {
+                    setfn: c,
+                    _p: PhantomData,
+                }
+            }
+        }
+    };
+}
+
+// SAFETY: This is only called when the parse result is a boolean, so it is ok to access to union
+// field.
+define_param_type!(flag, bool, Spec { ..DEFAULT }, |_p, r| unsafe {
+    r.__bindgen_anon_1.boolean
+});
+
+define_param_type!(
+    flag_no,
+    bool,
+    Spec {
+        flags: bindings::fs_param_neg_with_no as _,
+        ..DEFAULT
+    },
+    // SAFETY: This is only called when the parse result is a boolean, so it is ok to access to
+    // union field.
+    |_p, r| unsafe { r.__bindgen_anon_1.boolean }
+);
+
+define_param_type!(
+    bool,
+    bool,
+    Spec {
+        type_: Some(bindings::fs_param_is_bool),
+        ..DEFAULT
+    },
+    // SAFETY: This is only called when the parse result is a boolean, so it is ok to access to
+    // union field.
+    |_p, r| unsafe { r.__bindgen_anon_1.boolean }
+);
+
+define_param_type!(
+    u32,
+    u32,
+    Spec {
+        type_: Some(bindings::fs_param_is_u32),
+        ..DEFAULT
+    },
+    // SAFETY: This is only called when the parse result is a u32, so it is ok to access to union
+    // field.
+    |_p, r| unsafe { r.__bindgen_anon_1.uint_32 }
+);
+
+define_param_type!(
+    u32oct,
+    u32,
+    Spec {
+        type_: Some(bindings::fs_param_is_u32),
+        extra: 8 as _,
+        ..DEFAULT
+    },
+    // SAFETY: This is only called when the parse result is a u32, so it is ok to access to union
+    // field.
+    |_p, r| unsafe { r.__bindgen_anon_1.uint_32 }
+);
+
+define_param_type!(
+    u32hex,
+    u32,
+    Spec {
+        type_: Some(bindings::fs_param_is_u32),
+        extra: 16 as _,
+        ..DEFAULT
+    },
+    // SAFETY: This is only called when the parse result is a u32, so it is ok to access to union
+    // field.
+    |_p, r| unsafe { r.__bindgen_anon_1.uint_32 }
+);
+
+define_param_type!(
+    s32,
+    i32,
+    Spec {
+        type_: Some(bindings::fs_param_is_s32),
+        ..DEFAULT
+    },
+    // SAFETY: This is only called when the parse result is an i32, so it is ok to access to union
+    // field.
+    |_p, r| unsafe { r.__bindgen_anon_1.int_32 }
+);
+
+define_param_type!(
+    u64,
+    u64,
+    Spec {
+        type_: Some(bindings::fs_param_is_u64),
+        extra: 16 as _,
+        ..DEFAULT
+    },
+    // SAFETY: This is only called when the parse result is a u32, so it is ok to access to union
+    // field.
+    |_p, r| unsafe { r.__bindgen_anon_1.uint_64 }
+);
+
+define_param_type!(
+    string,
+    &CStr,
+    Spec {
+        type_: Some(bindings::fs_param_is_string),
+        ..DEFAULT
+    },
+    // SAFETY: This is only called when the parse result is a string, so it is ok to access to
+    // union field.
+    |p, _r| unsafe { CStr::from_char_ptr(p.__bindgen_anon_1.string) }
+);
+
+/// Module to support `enum` parameter types.
+pub mod enum_ {
+    use super::*;
+
+    #[doc(hidden)]
+    pub const fn spec(name: &'static CStr, options: ConstantTable<'static>) -> Spec {
+        Spec {
+            name,
+            type_: Some(bindings::fs_param_is_enum),
+            extra: options.first as *const _ as _,
+            ..DEFAULT
+        }
+    }
+
+    #[doc(hidden)]
+    pub const fn handler<S>(setfn: fn(&mut S, u32) -> Result) -> impl Handler<S> {
+        let c = move |s: &mut S, _p: &bindings::fs_parameter, r: &bindings::fs_parse_result| {
+            // SAFETY: This is only called when the parse result is an enum, so it is ok to access
+            // to union field.
+            setfn(s, unsafe { r.__bindgen_anon_1.uint_32 })
+        };
+        ConcreteHandler {
+            setfn: c,
+            _p: PhantomData,
+        }
+    }
+}
+
+const ZERO_SPEC: bindings::fs_parameter_spec = bindings::fs_parameter_spec {
+    name: core::ptr::null(),
+    type_: None,
+    opt: 0,
+    flags: 0,
+    data: core::ptr::null(),
+};
+
+/// A zero-terminated parameter spec array, followed by handlers.
+#[repr(C)]
+pub struct SpecArray<const N: usize, S: 'static> {
+    specs: [bindings::fs_parameter_spec; N],
+    sentinel: bindings::fs_parameter_spec,
+    handlers: [&'static dyn Handler<S>; N],
+}
+
+impl<const N: usize, S: 'static> SpecArray<N, S> {
+    /// Creates a new spec array.
+    ///
+    /// Users are encouraged to use the [`define_fs_params`] macro to define the
+    /// [`super::Context::PARAMS`] constant.
+    ///
+    /// # Safety
+    ///
+    /// The type of the elements in `handlers` must be compatible with the types in specs. For
+    /// example, if `specs` declares that the i-th element is a bool then the i-th handler
+    /// should be for a bool.
+    pub const unsafe fn new(specs: [Spec; N], handlers: [&'static dyn Handler<S>; N]) -> Self {
+        let mut array = Self {
+            specs: [ZERO_SPEC; N],
+            sentinel: ZERO_SPEC,
+            handlers,
+        };
+        let mut i = 0usize;
+        while i < N {
+            array.specs[i] = bindings::fs_parameter_spec {
+                name: specs[i].name.as_char_ptr(),
+                type_: specs[i].type_,
+                opt: i as _,
+                flags: specs[i].flags,
+                data: specs[i].extra,
+            };
+            i += 1;
+        }
+        array
+    }
+
+    /// Returns a [`SpecTable`] backed by `self`.
+    ///
+    /// This is used to essentially erase the array size.
+    pub const fn as_table(&self) -> SpecTable<'_, S> {
+        SpecTable {
+            first: &self.specs[0],
+            handlers: &self.handlers,
+            _p: PhantomData,
+        }
+    }
+}
+
+/// A parameter spec table.
+///
+/// The table is guaranteed to be zero-terminated.
+///
+/// Users are encouraged to use the [`define_fs_params`] macro to define the
+/// [`super::Context::PARAMS`] constant.
+pub struct SpecTable<'a, S: 'static> {
+    pub(super) first: &'a bindings::fs_parameter_spec,
+    pub(super) handlers: &'a [&'static dyn Handler<S>],
+    _p: PhantomData<S>,
+}
+
+impl<S> SpecTable<'static, S> {
+    pub(super) const fn empty() -> Self {
+        Self {
+            first: &ZERO_SPEC,
+            handlers: &[],
+            _p: PhantomData,
+        }
+    }
+}
+
+/// A zero-terminated parameter constant array.
+#[repr(C)]
+pub struct ConstantArray<const N: usize> {
+    consts: [bindings::constant_table; N],
+    sentinel: bindings::constant_table,
+}
+
+impl<const N: usize> ConstantArray<N> {
+    /// Creates a new constant array.
+    ///
+    /// Users are encouraged to use the [`define_fs_params`] macro to define the
+    /// [`super::Context::PARAMS`] constant.
+    pub const fn new(consts: [(&'static CStr, u32); N]) -> Self {
+        const ZERO: bindings::constant_table = bindings::constant_table {
+            name: core::ptr::null(),
+            value: 0,
+        };
+        let mut array = Self {
+            consts: [ZERO; N],
+            sentinel: ZERO,
+        };
+        let mut i = 0usize;
+        while i < N {
+            array.consts[i] = bindings::constant_table {
+                name: consts[i].0.as_char_ptr(),
+                value: consts[i].1 as _,
+            };
+            i += 1;
+        }
+        array
+    }
+
+    /// Returns a [`ConstantTable`] backed by `self`.
+    ///
+    /// This is used to essentially erase the array size.
+    pub const fn as_table(&self) -> ConstantTable<'_> {
+        ConstantTable {
+            first: &self.consts[0],
+        }
+    }
+}
+
+/// A parameter constant table.
+///
+/// The table is guaranteed to be zero-terminated.
+pub struct ConstantTable<'a> {
+    pub(super) first: &'a bindings::constant_table,
+}
+
+#[doc(hidden)]
+pub trait Handler<S> {
+    fn handle_param(
+        &self,
+        state: &mut S,
+        p: &bindings::fs_parameter,
+        r: &bindings::fs_parse_result,
+    ) -> Result;
+}
+
+struct ConcreteHandler<
+    S,
+    T: Fn(&mut S, &bindings::fs_parameter, &bindings::fs_parse_result) -> Result,
+> {
+    setfn: T,
+    _p: PhantomData<S>,
+}
+
+impl<S, T: Fn(&mut S, &bindings::fs_parameter, &bindings::fs_parse_result) -> Result> Handler<S>
+    for ConcreteHandler<S, T>
+{
+    fn handle_param(
+        &self,
+        state: &mut S,
+        p: &bindings::fs_parameter,
+        r: &bindings::fs_parse_result,
+    ) -> Result {
+        (self.setfn)(state, p, r)
+    }
+}
+
+/// Counts the number of comma-separated entries surrounded by braces.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::count_brace_items;
+///
+/// assert_eq!(0, count_brace_items!());
+/// assert_eq!(1, count_brace_items!({ A }));
+/// assert_eq!(1, count_brace_items!({ A },));
+/// assert_eq!(2, count_brace_items!({ A }, { B }));
+/// assert_eq!(2, count_brace_items!({ A }, { B },));
+/// assert_eq!(3, count_brace_items!({ A }, { B }, { C }));
+/// assert_eq!(3, count_brace_items!({ A }, { B }, { C },));
+/// ```
+#[macro_export]
+macro_rules! count_brace_items {
+    ({$($item:tt)*}, $($remaining:tt)*) => { 1 + $crate::count_brace_items!($($remaining)*) };
+    ({$($item:tt)*}) => { 1 };
+    () => { 0 };
+}
+
+/// Defines the file system parameters of a given file system context.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::prelude::*;
+/// # use kernel::{c_str, fs, str::CString};
+///
+/// #[derive(Default)]
+/// struct State {
+///     flag: Option<bool>,
+///     flag_no: Option<bool>,
+///     bool_value: Option<bool>,
+///     u32_value: Option<u32>,
+///     i32_value: Option<i32>,
+///     u64_value: Option<u64>,
+///     str_value: Option<CString>,
+///     enum_value: Option<u32>,
+/// }
+///
+/// fn set_u32(s: &mut Box<State>, v: u32) -> Result {
+///     s.u32_value = Some(v);
+///     Ok(())
+/// }
+///
+/// struct Example;
+///
+/// #[vtable]
+/// impl fs::Context<Self> for Example {
+///     type Data = Box<State>;
+///
+///     kernel::define_fs_params! {Box<State>,
+///         {flag, "flag", |s, v| { s.flag = Some(v); Ok(()) } },
+///         {flag_no, "flagno", |s, v| { s.flag_no = Some(v); Ok(()) } },
+///         {bool, "bool", |s, v| { s.bool_value = Some(v); Ok(()) } },
+///         {u32, "u32", set_u32 },
+///         {u32oct, "u32oct", set_u32 },
+///         {u32hex, "u32hex", set_u32 },
+///         {s32, "s32", |s, v| { s.i32_value = Some(v); Ok(()) } },
+///         {u64, "u64", |s, v| { s.u64_value = Some(v); Ok(()) } },
+///         {string, "string", |s, v| {
+///             s.str_value = Some(CString::try_from_fmt(fmt!("{v}"))?);
+///             Ok(())
+///         }},
+///         {enum, "enum", [("first", 10), ("second", 20)], |s, v| {
+///             s.enum_value = Some(v);
+///             Ok(())
+///         }},
+///     }
+///
+///     fn try_new() -> Result<Self::Data> {
+///         Ok(Box::try_new(State::default())?)
+///     }
+/// }
+///
+/// # impl fs::Type for Example {
+/// #    type Context = Self;
+/// #    const SUPER_TYPE: fs::Super = fs::Super::Independent;
+/// #    const NAME: &'static CStr = c_str!("example");
+/// #    const FLAGS: i32 = 0;
+/// #
+/// #    fn fill_super<'a>(
+/// #        _data: Box<State>,
+/// #        sb: fs::NewSuperBlock<'_, Self>,
+/// #    ) -> Result<&fs::SuperBlock<Self>> {
+/// #        let sb = sb.init(
+/// #            (),
+/// #            &fs::SuperParams {
+/// #                magic: 0x6578616d,
+/// #                ..fs::SuperParams::DEFAULT
+/// #            },
+/// #        )?;
+/// #        let sb = sb.init_root()?;
+/// #        Ok(sb)
+/// #    }
+/// # }
+/// ```
+#[macro_export]
+macro_rules! define_fs_params {
+    ($data_type:ty, $({$($t:tt)*}),+ $(,)?) => {
+        const PARAMS: $crate::fs::param::SpecTable<'static, $data_type> =
+            {
+                use $crate::fs::param::{self, ConstantArray, Spec, SpecArray, Handler};
+                use $crate::c_str;
+                const COUNT: usize = $crate::count_brace_items!($({$($t)*},)*);
+                const SPECS: [Spec; COUNT] = $crate::define_fs_params!(@specs $({$($t)*},)*);
+                const HANDLERS: [&dyn Handler<$data_type>; COUNT] =
+                    $crate::define_fs_params!(@handlers $data_type, $({$($t)*},)*);
+                // SAFETY: We defined matching specs and handlers above.
+                const ARRAY: SpecArray<COUNT, $data_type> =
+                    unsafe { SpecArray::new(SPECS, HANDLERS) };
+                ARRAY.as_table()
+            };
+    };
+
+    (@handlers $data_type:ty, $({$($t:tt)*},)*) => {
+        [ $($crate::define_fs_params!(@handler $data_type, $($t)*),)* ]
+    };
+    (@handler $data_type:ty, enum, $name:expr, $opts:expr, $closure:expr) => {
+        &param::enum_::handler::<$data_type>($closure)
+    };
+    (@handler $data_type:ty, $type:ident, $name:expr, $closure:expr) => {
+        &param::$type::handler::<$data_type>($closure)
+    };
+
+    (@specs $({$($t:tt)*},)*) => {[ $($crate::define_fs_params!(@spec $($t)*),)* ]};
+    (@spec enum, $name:expr, [$($opts:tt)*], $closure:expr) => {
+        {
+            const COUNT: usize = $crate::count_paren_items!($($opts)*);
+            const OPTIONS: ConstantArray<COUNT> =
+                ConstantArray::new($crate::define_fs_params!(@c_str_first $($opts)*));
+            param::enum_::spec(c_str!($name), OPTIONS.as_table())
+        }
+    };
+    (@spec $type:ident, $name:expr, $closure:expr) => { param::$type::spec(c_str!($name)) };
+
+    (@c_str_first $(($first:expr, $second:expr)),+ $(,)?) => {
+        [$((c_str!($first), $second),)*]
+    };
+}
diff --git a/rust/kernel/gpio.rs b/rust/kernel/gpio.rs
new file mode 100644
index 000000000000..53c7b398d10b
--- /dev/null
+++ b/rust/kernel/gpio.rs
@@ -0,0 +1,505 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Support for gpio device drivers.
+//!
+//! C header: [`include/linux/gpio/driver.h`](../../../../include/linux/gpio/driver.h)
+
+use crate::{
+    bindings, device, error::code::*, error::from_kernel_result, sync::LockClassKey,
+    types::PointerWrapper, Error, Result,
+};
+use core::{
+    cell::UnsafeCell,
+    marker::{PhantomData, PhantomPinned},
+    pin::Pin,
+};
+use macros::vtable;
+
+#[cfg(CONFIG_GPIOLIB_IRQCHIP)]
+pub use irqchip::{ChipWithIrqChip, RegistrationWithIrqChip};
+
+/// The direction of a gpio line.
+pub enum LineDirection {
+    /// Direction is input.
+    In = bindings::GPIO_LINE_DIRECTION_IN as _,
+
+    /// Direction is output.
+    Out = bindings::GPIO_LINE_DIRECTION_OUT as _,
+}
+
+/// A gpio chip.
+#[vtable]
+pub trait Chip {
+    /// Context data associated with the gpio chip.
+    ///
+    /// It determines the type of the context data passed to each of the methods of the trait.
+    type Data: PointerWrapper + Sync + Send;
+
+    /// Returns the direction of the given gpio line.
+    fn get_direction(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _offset: u32,
+    ) -> Result<LineDirection> {
+        Err(ENOTSUPP)
+    }
+
+    /// Configures the direction as input of the given gpio line.
+    fn direction_input(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _offset: u32,
+    ) -> Result {
+        Err(EIO)
+    }
+
+    /// Configures the direction as output of the given gpio line.
+    ///
+    /// The value that will be initially output is also specified.
+    fn direction_output(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _offset: u32,
+        _value: bool,
+    ) -> Result {
+        Err(ENOTSUPP)
+    }
+
+    /// Returns the current value of the given gpio line.
+    fn get(_data: <Self::Data as PointerWrapper>::Borrowed<'_>, _offset: u32) -> Result<bool> {
+        Err(EIO)
+    }
+
+    /// Sets the value of the given gpio line.
+    fn set(_data: <Self::Data as PointerWrapper>::Borrowed<'_>, _offset: u32, _value: bool) {}
+}
+
+/// A registration of a gpio chip.
+///
+/// # Examples
+///
+/// The following example registers an empty gpio chip.
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::{
+///     device::RawDevice,
+///     gpio::{self, Registration},
+/// };
+///
+/// struct MyGpioChip;
+/// #[vtable]
+/// impl gpio::Chip for MyGpioChip {
+///     type Data = ();
+/// }
+///
+/// fn example(parent: &dyn RawDevice) -> Result<Pin<Box<Registration<MyGpioChip>>>> {
+///     let mut r = Pin::from(Box::try_new(Registration::new())?);
+///     kernel::gpio_chip_register!(r.as_mut(), 32, None, parent, ())?;
+///     Ok(r)
+/// }
+/// ```
+pub struct Registration<T: Chip> {
+    gc: UnsafeCell<bindings::gpio_chip>,
+    parent: Option<device::Device>,
+    _p: PhantomData<T>,
+    _pin: PhantomPinned,
+}
+
+impl<T: Chip> Registration<T> {
+    /// Creates a new [`Registration`] but does not register it yet.
+    ///
+    /// It is allowed to move.
+    pub fn new() -> Self {
+        Self {
+            parent: None,
+            gc: UnsafeCell::new(bindings::gpio_chip::default()),
+            _pin: PhantomPinned,
+            _p: PhantomData,
+        }
+    }
+
+    /// Registers a gpio chip with the rest of the kernel.
+    ///
+    /// Users are encouraged to use the [`gpio_chip_register`] macro because it automatically
+    /// defines the lock classes and calls the registration function.
+    pub fn register(
+        self: Pin<&mut Self>,
+        gpio_count: u16,
+        base: Option<i32>,
+        parent: &dyn device::RawDevice,
+        data: T::Data,
+        lock_keys: [&'static LockClassKey; 2],
+    ) -> Result {
+        if self.parent.is_some() {
+            // Already registered.
+            return Err(EINVAL);
+        }
+
+        // SAFETY: We never move out of `this`.
+        let this = unsafe { self.get_unchecked_mut() };
+        {
+            let gc = this.gc.get_mut();
+
+            // Set up the callbacks.
+            gc.request = Some(bindings::gpiochip_generic_request);
+            gc.free = Some(bindings::gpiochip_generic_free);
+            if T::HAS_GET_DIRECTION {
+                gc.get_direction = Some(get_direction_callback::<T>);
+            }
+            if T::HAS_DIRECTION_INPUT {
+                gc.direction_input = Some(direction_input_callback::<T>);
+            }
+            if T::HAS_DIRECTION_OUTPUT {
+                gc.direction_output = Some(direction_output_callback::<T>);
+            }
+            if T::HAS_GET {
+                gc.get = Some(get_callback::<T>);
+            }
+            if T::HAS_SET {
+                gc.set = Some(set_callback::<T>);
+            }
+
+            // When a base is not explicitly given, use -1 for one to be picked.
+            if let Some(b) = base {
+                gc.base = b;
+            } else {
+                gc.base = -1;
+            }
+
+            gc.ngpio = gpio_count;
+            gc.parent = parent.raw_device();
+            gc.label = parent.name().as_char_ptr();
+
+            // TODO: Define `gc.owner` as well.
+        }
+
+        let data_pointer = <T::Data as PointerWrapper>::into_pointer(data);
+        // SAFETY: `gc` was initilised above, so it is valid.
+        let ret = unsafe {
+            bindings::gpiochip_add_data_with_key(
+                this.gc.get(),
+                data_pointer as _,
+                lock_keys[0].get(),
+                lock_keys[1].get(),
+            )
+        };
+        if ret < 0 {
+            // SAFETY: `data_pointer` was returned by `into_pointer` above.
+            unsafe { T::Data::from_pointer(data_pointer) };
+            return Err(Error::from_kernel_errno(ret));
+        }
+
+        this.parent = Some(device::Device::from_dev(parent));
+        Ok(())
+    }
+}
+
+// SAFETY: `Registration` doesn't offer any methods or access to fields when shared between threads
+// or CPUs, so it is safe to share it.
+unsafe impl<T: Chip> Sync for Registration<T> {}
+
+// SAFETY: Registration with and unregistration from the gpio subsystem can happen from any thread.
+// Additionally, `T::Data` (which is dropped during unregistration) is `Send`, so it is ok to move
+// `Registration` to different threads.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: Chip> Send for Registration<T> {}
+
+impl<T: Chip> Default for Registration<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T: Chip> Drop for Registration<T> {
+    /// Removes the registration from the kernel if it has completed successfully before.
+    fn drop(&mut self) {
+        if self.parent.is_some() {
+            // Get a pointer to the data stored in chip before destroying it.
+            // SAFETY: `gc` was during registration, which is guaranteed to have succeeded (because
+            // `parent` is `Some(_)`, so it remains valid.
+            let data_pointer = unsafe { bindings::gpiochip_get_data(self.gc.get()) };
+
+            // SAFETY: By the same argument above, `gc` is still valid.
+            unsafe { bindings::gpiochip_remove(self.gc.get()) };
+
+            // Free data as well.
+            // SAFETY: `data_pointer` was returned by `into_pointer` during registration.
+            unsafe { <T::Data as PointerWrapper>::from_pointer(data_pointer) };
+        }
+    }
+}
+
+/// Registers a gpio chip with the rest of the kernel.
+///
+/// It automatically defines the required lock classes.
+#[macro_export]
+macro_rules! gpio_chip_register {
+    ($reg:expr, $count:expr, $base:expr, $parent:expr, $data:expr $(,)?) => {{
+        static CLASS1: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        static CLASS2: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        $crate::gpio::Registration::register(
+            $reg,
+            $count,
+            $base,
+            $parent,
+            $data,
+            [&CLASS1, &CLASS2],
+        )
+    }};
+}
+
+unsafe extern "C" fn get_direction_callback<T: Chip>(
+    gc: *mut bindings::gpio_chip,
+    offset: core::ffi::c_uint,
+) -> core::ffi::c_int {
+    from_kernel_result! {
+        // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+        let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+        Ok(T::get_direction(data, offset)? as i32)
+    }
+}
+
+unsafe extern "C" fn direction_input_callback<T: Chip>(
+    gc: *mut bindings::gpio_chip,
+    offset: core::ffi::c_uint,
+) -> core::ffi::c_int {
+    from_kernel_result! {
+        // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+        let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+        T::direction_input(data, offset)?;
+        Ok(0)
+    }
+}
+
+unsafe extern "C" fn direction_output_callback<T: Chip>(
+    gc: *mut bindings::gpio_chip,
+    offset: core::ffi::c_uint,
+    value: core::ffi::c_int,
+) -> core::ffi::c_int {
+    from_kernel_result! {
+        // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+        let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+        T::direction_output(data, offset, value != 0)?;
+        Ok(0)
+    }
+}
+
+unsafe extern "C" fn get_callback<T: Chip>(
+    gc: *mut bindings::gpio_chip,
+    offset: core::ffi::c_uint,
+) -> core::ffi::c_int {
+    from_kernel_result! {
+        // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+        let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+        let v = T::get(data, offset)?;
+        Ok(v as _)
+    }
+}
+
+unsafe extern "C" fn set_callback<T: Chip>(
+    gc: *mut bindings::gpio_chip,
+    offset: core::ffi::c_uint,
+    value: core::ffi::c_int,
+) {
+    // SAFETY: The value stored as chip data was returned by `into_pointer` during registration.
+    let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+    T::set(data, offset, value != 0);
+}
+
+#[cfg(CONFIG_GPIOLIB_IRQCHIP)]
+mod irqchip {
+    use super::*;
+    use crate::irq;
+
+    /// A gpio chip that includes an irq chip.
+    pub trait ChipWithIrqChip: Chip {
+        /// Implements the irq flow for the gpio chip.
+        fn handle_irq_flow(
+            _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+            _desc: &irq::Descriptor,
+            _domain: &irq::Domain,
+        );
+    }
+
+    /// A registration of a gpio chip that includes an irq chip.
+    pub struct RegistrationWithIrqChip<T: ChipWithIrqChip> {
+        reg: Registration<T>,
+        irq_chip: UnsafeCell<bindings::irq_chip>,
+        parent_irq: u32,
+    }
+
+    impl<T: ChipWithIrqChip> RegistrationWithIrqChip<T> {
+        /// Creates a new [`RegistrationWithIrqChip`] but does not register it yet.
+        ///
+        /// It is allowed to move.
+        pub fn new() -> Self {
+            Self {
+                reg: Registration::new(),
+                irq_chip: UnsafeCell::new(bindings::irq_chip::default()),
+                parent_irq: 0,
+            }
+        }
+
+        /// Registers a gpio chip and its irq chip with the rest of the kernel.
+        ///
+        /// Users are encouraged to use the [`gpio_irq_chip_register`] macro because it
+        /// automatically defines the lock classes and calls the registration function.
+        pub fn register<U: irq::Chip<Data = T::Data>>(
+            mut self: Pin<&mut Self>,
+            gpio_count: u16,
+            base: Option<i32>,
+            parent: &dyn device::RawDevice,
+            data: T::Data,
+            parent_irq: u32,
+            lock_keys: [&'static LockClassKey; 2],
+        ) -> Result {
+            if self.reg.parent.is_some() {
+                // Already registered.
+                return Err(EINVAL);
+            }
+
+            // SAFETY: We never move out of `this`.
+            let this = unsafe { self.as_mut().get_unchecked_mut() };
+
+            // Initialise the irq_chip.
+            {
+                let irq_chip = this.irq_chip.get_mut();
+                irq_chip.name = parent.name().as_char_ptr();
+
+                // SAFETY: The gpio subsystem configures a pointer to `gpio_chip` as the irq chip
+                // data, so we use `IrqChipAdapter` to convert to the `T::Data`, which is the same
+                // as `irq::Chip::Data` per the bound above.
+                unsafe { irq::init_chip::<IrqChipAdapter<U>>(irq_chip) };
+            }
+
+            // Initialise gc irq state.
+            {
+                let girq = &mut this.reg.gc.get_mut().irq;
+                girq.chip = this.irq_chip.get();
+                // SAFETY: By leaving `parent_handler_data` set to `null`, the gpio subsystem
+                // initialises it to a pointer to the gpio chip, which is what `FlowHandler<T>`
+                // expects.
+                girq.parent_handler = unsafe { irq::new_flow_handler::<FlowHandler<T>>() };
+                girq.num_parents = 1;
+                girq.parents = &mut this.parent_irq;
+                this.parent_irq = parent_irq;
+                girq.default_type = bindings::IRQ_TYPE_NONE;
+                girq.handler = Some(bindings::handle_bad_irq);
+            }
+
+            // SAFETY: `reg` is pinned when `self` is.
+            let pinned = unsafe { self.map_unchecked_mut(|r| &mut r.reg) };
+            pinned.register(gpio_count, base, parent, data, lock_keys)
+        }
+    }
+
+    impl<T: ChipWithIrqChip> Default for RegistrationWithIrqChip<T> {
+        fn default() -> Self {
+            Self::new()
+        }
+    }
+
+    // SAFETY: `RegistrationWithIrqChip` doesn't offer any methods or access to fields when shared
+    // between threads or CPUs, so it is safe to share it.
+    unsafe impl<T: ChipWithIrqChip> Sync for RegistrationWithIrqChip<T> {}
+
+    // SAFETY: Registration with and unregistration from the gpio subsystem (including irq chips for
+    // them) can happen from any thread. Additionally, `T::Data` (which is dropped during
+    // unregistration) is `Send`, so it is ok to move `Registration` to different threads.
+    #[allow(clippy::non_send_fields_in_send_ty)]
+    unsafe impl<T: ChipWithIrqChip> Send for RegistrationWithIrqChip<T> where T::Data: Send {}
+
+    struct FlowHandler<T: ChipWithIrqChip>(PhantomData<T>);
+
+    impl<T: ChipWithIrqChip> irq::FlowHandler for FlowHandler<T> {
+        type Data = *mut bindings::gpio_chip;
+
+        fn handle_irq_flow(gc: *mut bindings::gpio_chip, desc: &irq::Descriptor) {
+            // SAFETY: `FlowHandler` is only used in gpio chips, and it is removed when the gpio is
+            // unregistered, so we know that `gc` must still be valid. We also know that the value
+            // stored as gpio data was returned by `T::Data::into_pointer` again because
+            // `FlowHandler` is a private structure only used in this way.
+            let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc)) };
+
+            // SAFETY: `gc` is valid (see comment above), so we can dereference it.
+            let domain = unsafe { irq::Domain::from_ptr((*gc).irq.domain) };
+
+            T::handle_irq_flow(data, desc, &domain);
+        }
+    }
+
+    /// Adapter from an irq chip with `gpio_chip` pointer as context to one where the gpio chip
+    /// data is passed as context.
+    struct IrqChipAdapter<T: irq::Chip>(PhantomData<T>);
+
+    #[vtable]
+    impl<T: irq::Chip> irq::Chip for IrqChipAdapter<T> {
+        type Data = *mut bindings::gpio_chip;
+
+        const HAS_SET_TYPE: bool = T::HAS_SET_TYPE;
+        const HAS_SET_WAKE: bool = T::HAS_SET_WAKE;
+
+        fn ack(gc: *mut bindings::gpio_chip, irq_data: &irq::IrqData) {
+            // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+            // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+            // registered, so `gc` is valid.
+            let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+            T::ack(data, irq_data);
+        }
+
+        fn mask(gc: *mut bindings::gpio_chip, irq_data: &irq::IrqData) {
+            // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+            // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+            // registered, so `gc` is valid.
+            let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+            T::mask(data, irq_data);
+        }
+
+        fn unmask(gc: *mut bindings::gpio_chip, irq_data: &irq::IrqData) {
+            // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+            // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+            // registered, so `gc` is valid.
+            let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+            T::unmask(data, irq_data);
+        }
+
+        fn set_type(
+            gc: *mut bindings::gpio_chip,
+            irq_data: &mut irq::LockedIrqData,
+            flow_type: u32,
+        ) -> Result<irq::ExtraResult> {
+            // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+            // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+            // registered, so `gc` is valid.
+            let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+            T::set_type(data, irq_data, flow_type)
+        }
+
+        fn set_wake(gc: *mut bindings::gpio_chip, irq_data: &irq::IrqData, on: bool) -> Result {
+            // SAFETY: `IrqChipAdapter` is a private struct, only used when the data stored in the
+            // gpio chip is known to come from `T::Data`, and only valid while the gpio chip is
+            // registered, so `gc` is valid.
+            let data = unsafe { T::Data::borrow(bindings::gpiochip_get_data(gc as _)) };
+            T::set_wake(data, irq_data, on)
+        }
+    }
+
+    /// Registers a gpio chip and its irq chip with the rest of the kernel.
+    ///
+    /// It automatically defines the required lock classes.
+    #[macro_export]
+    macro_rules! gpio_irq_chip_register {
+        ($reg:expr, $irqchip:ty, $count:expr, $base:expr, $parent:expr, $data:expr,
+         $parent_irq:expr $(,)?) => {{
+            static CLASS1: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+            static CLASS2: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+            $crate::gpio::RegistrationWithIrqChip::register::<$irqchip>(
+                $reg,
+                $count,
+                $base,
+                $parent,
+                $data,
+                $parent_irq,
+                [&CLASS1, &CLASS2],
+            )
+        }};
+    }
+}
diff --git a/rust/kernel/hwrng.rs b/rust/kernel/hwrng.rs
new file mode 100644
index 000000000000..5918f567c332
--- /dev/null
+++ b/rust/kernel/hwrng.rs
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Hardware Random Number Generator.
+//!
+//! C header: [`include/linux/hw_random.h`](../../../../include/linux/hw_random.h)
+
+use alloc::{boxed::Box, slice::from_raw_parts_mut};
+
+use crate::{
+    bindings, error::code::*, error::from_kernel_result, str::CString, to_result,
+    types::PointerWrapper, Result, ScopeGuard,
+};
+use macros::vtable;
+
+use core::{cell::UnsafeCell, fmt, marker::PhantomData, pin::Pin};
+
+/// This trait is implemented in order to provide callbacks to `struct hwrng`.
+#[vtable]
+pub trait Operations {
+    /// The pointer type that will be used to hold user-defined data type.
+    type Data: PointerWrapper + Send + Sync = ();
+
+    /// Initialization callback, can be left undefined.
+    fn init(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+        Err(EINVAL)
+    }
+
+    /// Cleanup callback, can be left undefined.
+    fn cleanup(_data: Self::Data) {}
+
+    /// Read data into the provided buffer.
+    /// Drivers can fill up to max bytes of data into the buffer.
+    /// The buffer is aligned for any type and its size is a multiple of 4 and >= 32 bytes.
+    fn read(
+        data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        buffer: &mut [u8],
+        wait: bool,
+    ) -> Result<u32>;
+}
+
+/// Registration structure for Hardware Random Number Generator driver.
+pub struct Registration<T: Operations> {
+    hwrng: UnsafeCell<bindings::hwrng>,
+    name: Option<CString>,
+    registered: bool,
+    _p: PhantomData<T>,
+}
+
+impl<T: Operations> Registration<T> {
+    /// Creates new instance of registration.
+    ///
+    /// The data must be registered.
+    pub fn new() -> Self {
+        Self {
+            hwrng: UnsafeCell::new(bindings::hwrng::default()),
+            name: None,
+            registered: false,
+            _p: PhantomData,
+        }
+    }
+
+    /// Returns a registered and pinned, heap-allocated representation of the registration.
+    pub fn new_pinned(
+        name: fmt::Arguments<'_>,
+        quality: u16,
+        data: T::Data,
+    ) -> Result<Pin<Box<Self>>> {
+        let mut reg = Pin::from(Box::try_new(Self::new())?);
+        reg.as_mut().register(name, quality, data)?;
+        Ok(reg)
+    }
+
+    /// Registers a hwrng device within the rest of the kernel.
+    ///
+    /// It must be pinned because the memory block that represents
+    /// the registration may be self-referential.
+    pub fn register(
+        self: Pin<&mut Self>,
+        name: fmt::Arguments<'_>,
+        quality: u16,
+        data: T::Data,
+    ) -> Result {
+        // SAFETY: We never move out of `this`.
+        let this = unsafe { self.get_unchecked_mut() };
+
+        if this.registered {
+            return Err(EINVAL);
+        }
+
+        let data_pointer = data.into_pointer();
+
+        // SAFETY: `data_pointer` comes from the call to `data.into_pointer()` above.
+        let guard = ScopeGuard::new(|| unsafe {
+            T::Data::from_pointer(data_pointer);
+        });
+
+        let name = CString::try_from_fmt(name)?;
+
+        // SAFETY: Registration is pinned and contains allocated and set to zero
+        // `bindings::hwrng` structure.
+        Self::init_hwrng(
+            unsafe { &mut *this.hwrng.get() },
+            &name,
+            quality,
+            data_pointer,
+        );
+
+        // SAFETY: `bindings::hwrng` is initialized above which guarantees safety.
+        to_result(unsafe { bindings::hwrng_register(this.hwrng.get()) })?;
+
+        this.registered = true;
+        this.name = Some(name);
+        guard.dismiss();
+        Ok(())
+    }
+
+    fn init_hwrng(
+        hwrng: &mut bindings::hwrng,
+        name: &CString,
+        quality: u16,
+        data: *const core::ffi::c_void,
+    ) {
+        hwrng.name = name.as_char_ptr();
+
+        hwrng.init = if T::HAS_INIT {
+            Some(Self::init_callback)
+        } else {
+            None
+        };
+        hwrng.cleanup = if T::HAS_CLEANUP {
+            Some(Self::cleanup_callback)
+        } else {
+            None
+        };
+        hwrng.data_present = None;
+        hwrng.data_read = None;
+        hwrng.read = Some(Self::read_callback);
+
+        hwrng.priv_ = data as _;
+        hwrng.quality = quality;
+
+        // SAFETY: All fields are properly initialized as
+        // remaining fields `list`, `ref` and `cleanup_done` are already
+        // zeroed by `bindings::hwrng::default()` call.
+    }
+
+    unsafe extern "C" fn init_callback(rng: *mut bindings::hwrng) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: `priv` private data field was initialized during creation of
+            // the `bindings::hwrng` in `Self::init_hwrng` method. This callback is only
+            // called once the driver is registered.
+            let data = unsafe { T::Data::borrow((*rng).priv_ as *const _) };
+            T::init(data)?;
+            Ok(0)
+        }
+    }
+
+    unsafe extern "C" fn cleanup_callback(rng: *mut bindings::hwrng) {
+        // SAFETY: `priv` private data field was initialized during creation of
+        // the `bindings::hwrng` in `Self::init_hwrng` method. This callback is only
+        // called once the driver is registered.
+        let data = unsafe { T::Data::from_pointer((*rng).priv_ as *const _) };
+        T::cleanup(data);
+    }
+
+    unsafe extern "C" fn read_callback(
+        rng: *mut bindings::hwrng,
+        data: *mut core::ffi::c_void,
+        max: usize,
+        wait: bindings::bool_,
+    ) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: `priv` private data field was initialized during creation of
+            // the `bindings::hwrng` in `Self::init_hwrng` method. This callback is only
+            // called once the driver is registered.
+            let drv_data = unsafe { T::Data::borrow((*rng).priv_ as *const _) };
+
+            // SAFETY: Slice is created from `data` and `max` arguments that are C's buffer
+            // along with its size in bytes that are safe for this conversion.
+            let buffer = unsafe { from_raw_parts_mut(data as *mut u8, max) };
+            let ret = T::read(drv_data, buffer, wait)?;
+            Ok(ret as _)
+        }
+    }
+}
+
+impl<T: Operations> Default for Registration<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+// SAFETY: `Registration` does not expose any of its state across threads.
+unsafe impl<T: Operations> Sync for Registration<T> {}
+
+// SAFETY: `Registration` is not restricted to a single thread,
+// its `T::Data` is also `Send` so it may be moved to different threads.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: Operations> Send for Registration<T> {}
+
+impl<T: Operations> Drop for Registration<T> {
+    /// Removes the registration from the kernel if it has completed successfully before.
+    fn drop(&mut self) {
+        // SAFETY: The instance of Registration<T> is unregistered only
+        // after being initialized and registered before.
+        if self.registered {
+            unsafe { bindings::hwrng_unregister(self.hwrng.get()) };
+        }
+    }
+}
diff --git a/rust/kernel/io_buffer.rs b/rust/kernel/io_buffer.rs
new file mode 100644
index 000000000000..ccecc4763aca
--- /dev/null
+++ b/rust/kernel/io_buffer.rs
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Buffers used in IO.
+
+use crate::Result;
+use alloc::vec::Vec;
+use core::mem::{size_of, MaybeUninit};
+
+/// Represents a buffer to be read from during IO.
+pub trait IoBufferReader {
+    /// Returns the number of bytes left to be read from the io buffer.
+    ///
+    /// Note that even reading less than this number of bytes may fail.
+    fn len(&self) -> usize;
+
+    /// Returns `true` if no data is available in the io buffer.
+    fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    /// Reads raw data from the io buffer into a raw kernel buffer.
+    ///
+    /// # Safety
+    ///
+    /// The output buffer must be valid.
+    unsafe fn read_raw(&mut self, out: *mut u8, len: usize) -> Result;
+
+    /// Reads all data remaining in the io buffer.
+    ///
+    /// Returns `EFAULT` if the address does not currently point to mapped, readable memory.
+    fn read_all(&mut self) -> Result<Vec<u8>> {
+        let mut data = Vec::<u8>::new();
+        data.try_resize(self.len(), 0)?;
+
+        // SAFETY: The output buffer is valid as we just allocated it.
+        unsafe { self.read_raw(data.as_mut_ptr(), data.len())? };
+        Ok(data)
+    }
+
+    /// Reads a byte slice from the io buffer.
+    ///
+    /// Returns `EFAULT` if the byte slice is bigger than the remaining size of the user slice or
+    /// if the address does not currently point to mapped, readable memory.
+    fn read_slice(&mut self, data: &mut [u8]) -> Result {
+        // SAFETY: The output buffer is valid as it's coming from a live reference.
+        unsafe { self.read_raw(data.as_mut_ptr(), data.len()) }
+    }
+
+    /// Reads the contents of a plain old data (POD) type from the io buffer.
+    fn read<T: ReadableFromBytes>(&mut self) -> Result<T> {
+        let mut out = MaybeUninit::<T>::uninit();
+        // SAFETY: The buffer is valid as it was just allocated.
+        unsafe { self.read_raw(out.as_mut_ptr() as _, size_of::<T>()) }?;
+        // SAFETY: We just initialised the data.
+        Ok(unsafe { out.assume_init() })
+    }
+}
+
+/// Represents a buffer to be written to during IO.
+pub trait IoBufferWriter {
+    /// Returns the number of bytes left to be written into the io buffer.
+    ///
+    /// Note that even writing less than this number of bytes may fail.
+    fn len(&self) -> usize;
+
+    /// Returns `true` if the io buffer cannot hold any additional data.
+    fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    /// Writes zeroes to the io buffer.
+    ///
+    /// Differently from the other write functions, `clear` will zero as much as it can and update
+    /// the writer internal state to reflect this. It will, however, return an error if it cannot
+    /// clear `len` bytes.
+    ///
+    /// For example, if a caller requests that 100 bytes be cleared but a segfault happens after
+    /// 20 bytes, then EFAULT is returned and the writer is advanced by 20 bytes.
+    fn clear(&mut self, len: usize) -> Result;
+
+    /// Writes a byte slice into the io buffer.
+    ///
+    /// Returns `EFAULT` if the byte slice is bigger than the remaining size of the io buffer or if
+    /// the address does not currently point to mapped, writable memory.
+    fn write_slice(&mut self, data: &[u8]) -> Result {
+        // SAFETY: The input buffer is valid as it's coming from a live reference.
+        unsafe { self.write_raw(data.as_ptr(), data.len()) }
+    }
+
+    /// Writes raw data to the io buffer from a raw kernel buffer.
+    ///
+    /// # Safety
+    ///
+    /// The input buffer must be valid.
+    unsafe fn write_raw(&mut self, data: *const u8, len: usize) -> Result;
+
+    /// Writes the contents of the given data into the io buffer.
+    fn write<T: WritableToBytes>(&mut self, data: &T) -> Result {
+        // SAFETY: The input buffer is valid as it's coming from a live
+        // reference to a type that implements `WritableToBytes`.
+        unsafe { self.write_raw(data as *const T as _, size_of::<T>()) }
+    }
+}
+
+/// Specifies that a type is safely readable from byte slices.
+///
+/// Not all types can be safely read from byte slices; examples from
+/// <https://doc.rust-lang.org/reference/behavior-considered-undefined.html> include `bool`
+/// that must be either `0` or `1`, and `char` that cannot be a surrogate or above `char::MAX`.
+///
+/// # Safety
+///
+/// Implementers must ensure that the type is made up only of types that can be safely read from
+/// arbitrary byte sequences (e.g., `u32`, `u64`, etc.).
+pub unsafe trait ReadableFromBytes {}
+
+// SAFETY: All bit patterns are acceptable values of the types below.
+unsafe impl ReadableFromBytes for u8 {}
+unsafe impl ReadableFromBytes for u16 {}
+unsafe impl ReadableFromBytes for u32 {}
+unsafe impl ReadableFromBytes for u64 {}
+unsafe impl ReadableFromBytes for usize {}
+unsafe impl ReadableFromBytes for i8 {}
+unsafe impl ReadableFromBytes for i16 {}
+unsafe impl ReadableFromBytes for i32 {}
+unsafe impl ReadableFromBytes for i64 {}
+unsafe impl ReadableFromBytes for isize {}
+
+/// Specifies that a type is safely writable to byte slices.
+///
+/// This means that we don't read undefined values (which leads to UB) in preparation for writing
+/// to the byte slice. It also ensures that no potentially sensitive information is leaked into the
+/// byte slices.
+///
+/// # Safety
+///
+/// A type must not include padding bytes and must be fully initialised to safely implement
+/// [`WritableToBytes`] (i.e., it doesn't contain [`MaybeUninit`] fields). A composition of
+/// writable types in a structure is not necessarily writable because it may result in padding
+/// bytes.
+pub unsafe trait WritableToBytes {}
+
+// SAFETY: Initialised instances of the following types have no uninitialised portions.
+unsafe impl WritableToBytes for u8 {}
+unsafe impl WritableToBytes for u16 {}
+unsafe impl WritableToBytes for u32 {}
+unsafe impl WritableToBytes for u64 {}
+unsafe impl WritableToBytes for usize {}
+unsafe impl WritableToBytes for i8 {}
+unsafe impl WritableToBytes for i16 {}
+unsafe impl WritableToBytes for i32 {}
+unsafe impl WritableToBytes for i64 {}
+unsafe impl WritableToBytes for isize {}
diff --git a/rust/kernel/io_mem.rs b/rust/kernel/io_mem.rs
new file mode 100644
index 000000000000..ff6886a9e3b7
--- /dev/null
+++ b/rust/kernel/io_mem.rs
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Memory-mapped IO.
+//!
+//! C header: [`include/asm-generic/io.h`](../../../../include/asm-generic/io.h)
+
+#![allow(dead_code)]
+
+use crate::{bindings, error::code::*, Result};
+use core::convert::TryInto;
+
+/// Represents a memory resource.
+pub struct Resource {
+    offset: bindings::resource_size_t,
+    size: bindings::resource_size_t,
+}
+
+impl Resource {
+    pub(crate) fn new(
+        start: bindings::resource_size_t,
+        end: bindings::resource_size_t,
+    ) -> Option<Self> {
+        if start == 0 {
+            return None;
+        }
+        Some(Self {
+            offset: start,
+            size: end.checked_sub(start)?.checked_add(1)?,
+        })
+    }
+}
+
+/// Represents a memory block of at least `SIZE` bytes.
+///
+/// # Invariants
+///
+/// `ptr` is a non-null and valid address of at least `SIZE` bytes and returned by an `ioremap`
+/// variant. `ptr` is also 8-byte aligned.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::io_mem::{IoMem, Resource};
+///
+/// fn test(res: Resource) -> Result {
+///     // Create an io mem block of at least 100 bytes.
+///     // SAFETY: No DMA operations are initiated through `mem`.
+///     let mem = unsafe { IoMem::<100>::try_new(res) }?;
+///
+///     // Read one byte from offset 10.
+///     let v = mem.readb(10);
+///
+///     // Write value to offset 20.
+///     mem.writeb(v, 20);
+///
+///     Ok(())
+/// }
+/// ```
+pub struct IoMem<const SIZE: usize> {
+    ptr: usize,
+}
+
+macro_rules! define_read {
+    ($(#[$attr:meta])* $name:ident, $try_name:ident, $type_name:ty) => {
+        /// Reads IO data from the given offset known, at compile time.
+        ///
+        /// If the offset is not known at compile time, the build will fail.
+        $(#[$attr])*
+        #[inline]
+        pub fn $name(&self, offset: usize) -> $type_name {
+            Self::check_offset::<$type_name>(offset);
+            let ptr = self.ptr.wrapping_add(offset);
+            // SAFETY: The type invariants guarantee that `ptr` is a valid pointer. The check above
+            // guarantees that the code won't build if `offset` makes the read go out of bounds
+            // (including the type size).
+            unsafe { bindings::$name(ptr as _) }
+        }
+
+        /// Reads IO data from the given offset.
+        ///
+        /// It fails if/when the offset (plus the type size) is out of bounds.
+        $(#[$attr])*
+        pub fn $try_name(&self, offset: usize) -> Result<$type_name> {
+            if !Self::offset_ok::<$type_name>(offset) {
+                return Err(EINVAL);
+            }
+            let ptr = self.ptr.wrapping_add(offset);
+            // SAFETY: The type invariants guarantee that `ptr` is a valid pointer. The check above
+            // returns an error if `offset` would make the read go out of bounds (including the
+            // type size).
+            Ok(unsafe { bindings::$name(ptr as _) })
+        }
+    };
+}
+
+macro_rules! define_write {
+    ($(#[$attr:meta])* $name:ident, $try_name:ident, $type_name:ty) => {
+        /// Writes IO data to the given offset, known at compile time.
+        ///
+        /// If the offset is not known at compile time, the build will fail.
+        $(#[$attr])*
+        #[inline]
+        pub fn $name(&self, value: $type_name, offset: usize) {
+            Self::check_offset::<$type_name>(offset);
+            let ptr = self.ptr.wrapping_add(offset);
+            // SAFETY: The type invariants guarantee that `ptr` is a valid pointer. The check above
+            // guarantees that the code won't link if `offset` makes the write go out of bounds
+            // (including the type size).
+            unsafe { bindings::$name(value, ptr as _) }
+        }
+
+        /// Writes IO data to the given offset.
+        ///
+        /// It fails if/when the offset (plus the type size) is out of bounds.
+        $(#[$attr])*
+        pub fn $try_name(&self, value: $type_name, offset: usize) -> Result {
+            if !Self::offset_ok::<$type_name>(offset) {
+                return Err(EINVAL);
+            }
+            let ptr = self.ptr.wrapping_add(offset);
+            // SAFETY: The type invariants guarantee that `ptr` is a valid pointer. The check above
+            // returns an error if `offset` would make the write go out of bounds (including the
+            // type size).
+            unsafe { bindings::$name(value, ptr as _) };
+            Ok(())
+        }
+    };
+}
+
+impl<const SIZE: usize> IoMem<SIZE> {
+    /// Tries to create a new instance of a memory block.
+    ///
+    /// The resource described by `res` is mapped into the CPU's address space so that it can be
+    /// accessed directly. It is also consumed by this function so that it can't be mapped again
+    /// to a different address.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that either (a) the resulting interface cannot be used to initiate DMA
+    /// operations, or (b) that DMA operations initiated via the returned interface use DMA handles
+    /// allocated through the `dma` module.
+    pub unsafe fn try_new(res: Resource) -> Result<Self> {
+        // Check that the resource has at least `SIZE` bytes in it.
+        if res.size < SIZE.try_into()? {
+            return Err(EINVAL);
+        }
+
+        // To be able to check pointers at compile time based only on offsets, we need to guarantee
+        // that the base pointer is minimally aligned. So we conservatively expect at least 8 bytes.
+        if res.offset % 8 != 0 {
+            crate::pr_err!("Physical address is not 64-bit aligned: {:x}", res.offset);
+            return Err(EDOM);
+        }
+
+        // Try to map the resource.
+        // SAFETY: Just mapping the memory range.
+        let addr = unsafe { bindings::ioremap(res.offset, res.size as _) };
+        if addr.is_null() {
+            Err(ENOMEM)
+        } else {
+            // INVARIANT: `addr` is non-null and was returned by `ioremap`, so it is valid. It is
+            // also 8-byte aligned because we checked it above.
+            Ok(Self { ptr: addr as usize })
+        }
+    }
+
+    #[inline]
+    const fn offset_ok<T>(offset: usize) -> bool {
+        let type_size = core::mem::size_of::<T>();
+        if let Some(end) = offset.checked_add(type_size) {
+            end <= SIZE && offset % type_size == 0
+        } else {
+            false
+        }
+    }
+
+    fn offset_ok_of_val<T: ?Sized>(offset: usize, value: &T) -> bool {
+        let value_size = core::mem::size_of_val(value);
+        let value_alignment = core::mem::align_of_val(value);
+        if let Some(end) = offset.checked_add(value_size) {
+            end <= SIZE && offset % value_alignment == 0
+        } else {
+            false
+        }
+    }
+
+    #[inline]
+    const fn check_offset<T>(offset: usize) {
+        crate::build_assert!(Self::offset_ok::<T>(offset), "IoMem offset overflow");
+    }
+
+    /// Copy memory block from an i/o memory by filling the specified buffer with it.
+    ///
+    /// # Examples
+    /// ```
+    /// use kernel::io_mem::{self, IoMem, Resource};
+    ///
+    /// fn test(res: Resource) -> Result {
+    ///     // Create an i/o memory block of at least 100 bytes.
+    ///     let mem = unsafe { IoMem::<100>::try_new(res) }?;
+    ///
+    ///     let mut buffer: [u8; 32] = [0; 32];
+    ///
+    ///     // Memcpy 16 bytes from an offset 10 of i/o memory block into the buffer.
+    ///     mem.try_memcpy_fromio(&mut buffer[..16], 10)?;
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    pub fn try_memcpy_fromio(&self, buffer: &mut [u8], offset: usize) -> Result {
+        if !Self::offset_ok_of_val(offset, buffer) {
+            return Err(EINVAL);
+        }
+
+        let ptr = self.ptr.wrapping_add(offset);
+
+        // SAFETY:
+        //   - The type invariants guarantee that `ptr` is a valid pointer.
+        //   - The bounds of `buffer` are checked with a call to `offset_ok_of_val()`.
+        unsafe {
+            bindings::memcpy_fromio(
+                buffer.as_mut_ptr() as *mut _,
+                ptr as *const _,
+                buffer.len() as _,
+            )
+        };
+        Ok(())
+    }
+
+    define_read!(readb, try_readb, u8);
+    define_read!(readw, try_readw, u16);
+    define_read!(readl, try_readl, u32);
+    define_read!(
+        #[cfg(CONFIG_64BIT)]
+        readq,
+        try_readq,
+        u64
+    );
+
+    define_read!(readb_relaxed, try_readb_relaxed, u8);
+    define_read!(readw_relaxed, try_readw_relaxed, u16);
+    define_read!(readl_relaxed, try_readl_relaxed, u32);
+    define_read!(
+        #[cfg(CONFIG_64BIT)]
+        readq_relaxed,
+        try_readq_relaxed,
+        u64
+    );
+
+    define_write!(writeb, try_writeb, u8);
+    define_write!(writew, try_writew, u16);
+    define_write!(writel, try_writel, u32);
+    define_write!(
+        #[cfg(CONFIG_64BIT)]
+        writeq,
+        try_writeq,
+        u64
+    );
+
+    define_write!(writeb_relaxed, try_writeb_relaxed, u8);
+    define_write!(writew_relaxed, try_writew_relaxed, u16);
+    define_write!(writel_relaxed, try_writel_relaxed, u32);
+    define_write!(
+        #[cfg(CONFIG_64BIT)]
+        writeq_relaxed,
+        try_writeq_relaxed,
+        u64
+    );
+}
+
+impl<const SIZE: usize> Drop for IoMem<SIZE> {
+    fn drop(&mut self) {
+        // SAFETY: By the type invariant, `self.ptr` is a value returned by a previous successful
+        // call to `ioremap`.
+        unsafe { bindings::iounmap(self.ptr as _) };
+    }
+}
diff --git a/rust/kernel/iov_iter.rs b/rust/kernel/iov_iter.rs
new file mode 100644
index 000000000000..b9b8dc882bd0
--- /dev/null
+++ b/rust/kernel/iov_iter.rs
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! IO vector iterators.
+//!
+//! C header: [`include/linux/uio.h`](../../../../include/linux/uio.h)
+
+use crate::{
+    bindings,
+    error::code::*,
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    Result,
+};
+
+/// Wraps the kernel's `struct iov_iter`.
+///
+/// # Invariants
+///
+/// The pointer `IovIter::ptr` is non-null and valid.
+pub struct IovIter {
+    ptr: *mut bindings::iov_iter,
+}
+
+impl IovIter {
+    fn common_len(&self) -> usize {
+        // SAFETY: `IovIter::ptr` is guaranteed to be valid by the type invariants.
+        unsafe { (*self.ptr).count }
+    }
+
+    /// Constructs a new [`struct iov_iter`] wrapper.
+    ///
+    /// # Safety
+    ///
+    /// The pointer `ptr` must be non-null and valid for the lifetime of the object.
+    pub(crate) unsafe fn from_ptr(ptr: *mut bindings::iov_iter) -> Self {
+        // INVARIANTS: the safety contract ensures the type invariant will hold.
+        Self { ptr }
+    }
+}
+
+impl IoBufferWriter for IovIter {
+    fn len(&self) -> usize {
+        self.common_len()
+    }
+
+    fn clear(&mut self, mut len: usize) -> Result {
+        while len > 0 {
+            // SAFETY: `IovIter::ptr` is guaranteed to be valid by the type invariants.
+            let written = unsafe { bindings::iov_iter_zero(len, self.ptr) };
+            if written == 0 {
+                return Err(EFAULT);
+            }
+
+            len -= written;
+        }
+        Ok(())
+    }
+
+    unsafe fn write_raw(&mut self, data: *const u8, len: usize) -> Result {
+        let res = unsafe { bindings::copy_to_iter(data as _, len, self.ptr) };
+        if res != len {
+            Err(EFAULT)
+        } else {
+            Ok(())
+        }
+    }
+}
+
+impl IoBufferReader for IovIter {
+    fn len(&self) -> usize {
+        self.common_len()
+    }
+
+    unsafe fn read_raw(&mut self, out: *mut u8, len: usize) -> Result {
+        let res = unsafe { bindings::copy_from_iter(out as _, len, self.ptr) };
+        if res != len {
+            Err(EFAULT)
+        } else {
+            Ok(())
+        }
+    }
+}
diff --git a/rust/kernel/irq.rs b/rust/kernel/irq.rs
new file mode 100644
index 000000000000..f2fa270dd728
--- /dev/null
+++ b/rust/kernel/irq.rs
@@ -0,0 +1,681 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Interrupts and interrupt chips.
+//!
+//! See <https://www.kernel.org/doc/Documentation/core-api/genericirq.rst>.
+//!
+//! C headers: [`include/linux/irq.h`](../../../../include/linux/irq.h) and
+//! [`include/linux/interrupt.h`](../../../../include/linux/interrupt.h).
+
+#![allow(dead_code)]
+
+use crate::{
+    bindings,
+    error::{from_kernel_result, to_result},
+    str::CString,
+    types::PointerWrapper,
+    Error, Result, ScopeGuard,
+};
+use core::{fmt, marker::PhantomData, ops::Deref};
+use macros::vtable;
+
+/// The type of irq hardware numbers.
+pub type HwNumber = bindings::irq_hw_number_t;
+
+/// Wraps the kernel's `struct irq_data`.
+///
+/// # Invariants
+///
+/// The pointer `IrqData::ptr` is non-null and valid.
+pub struct IrqData {
+    ptr: *mut bindings::irq_data,
+}
+
+impl IrqData {
+    /// Creates a new `IrqData` instance from a raw pointer.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `ptr` is non-null and valid when the function is called, and that
+    /// it remains valid for the lifetime of the return [`IrqData`] instance.
+    unsafe fn from_ptr(ptr: *mut bindings::irq_data) -> Self {
+        // INVARIANTS: By the safety requirements, the instance we're creating satisfies the type
+        // invariants.
+        Self { ptr }
+    }
+
+    /// Returns the hardware irq number.
+    pub fn hwirq(&self) -> HwNumber {
+        // SAFETY: By the type invariants, it's ok to dereference `ptr`.
+        unsafe { (*self.ptr).hwirq }
+    }
+}
+
+/// Wraps the kernel's `struct irq_data` when it is locked.
+///
+/// Being locked allows additional operations to be performed on the data.
+pub struct LockedIrqData(IrqData);
+
+impl LockedIrqData {
+    /// Sets the high-level irq flow handler to the builtin one for level-triggered irqs.
+    pub fn set_level_handler(&mut self) {
+        // SAFETY: By the type invariants of `self.0`, we know `self.0.ptr` is valid.
+        unsafe { bindings::irq_set_handler_locked(self.0.ptr, Some(bindings::handle_level_irq)) };
+    }
+
+    /// Sets the high-level irq flow handler to the builtin one for edge-triggered irqs.
+    pub fn set_edge_handler(&mut self) {
+        // SAFETY: By the type invariants of `self.0`, we know `self.0.ptr` is valid.
+        unsafe { bindings::irq_set_handler_locked(self.0.ptr, Some(bindings::handle_edge_irq)) };
+    }
+
+    /// Sets the high-level irq flow handler to the builtin one for bad irqs.
+    pub fn set_bad_handler(&mut self) {
+        // SAFETY: By the type invariants of `self.0`, we know `self.0.ptr` is valid.
+        unsafe { bindings::irq_set_handler_locked(self.0.ptr, Some(bindings::handle_bad_irq)) };
+    }
+}
+
+impl Deref for LockedIrqData {
+    type Target = IrqData;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+/// Extra information returned by some of the [`Chip`] methods on success.
+pub enum ExtraResult {
+    /// Indicates that the caller (irq core) will update the descriptor state.
+    None = bindings::IRQ_SET_MASK_OK as _,
+
+    /// Indicates that the callee (irq chip implementation) already updated the descriptor state.
+    NoCopy = bindings::IRQ_SET_MASK_OK_NOCOPY as _,
+
+    /// Same as [`ExtraResult::None`] in terms of updating descriptor state. It is used in stacked
+    /// irq chips to indicate that descendant chips should be skipped.
+    Done = bindings::IRQ_SET_MASK_OK_DONE as _,
+}
+
+/// An irq chip.
+///
+/// It is a trait for the functions defined in [`struct irq_chip`].
+///
+/// [`struct irq_chip`]: ../../../include/linux/irq.h
+#[vtable]
+pub trait Chip: Sized {
+    /// The type of the context data stored in the irq chip and made available on each callback.
+    type Data: PointerWrapper;
+
+    /// Called at the start of a new interrupt.
+    fn ack(data: <Self::Data as PointerWrapper>::Borrowed<'_>, irq_data: &IrqData);
+
+    /// Masks an interrupt source.
+    fn mask(data: <Self::Data as PointerWrapper>::Borrowed<'_>, irq_data: &IrqData);
+
+    /// Unmasks an interrupt source.
+    fn unmask(_data: <Self::Data as PointerWrapper>::Borrowed<'_>, irq_data: &IrqData);
+
+    /// Sets the flow type of an interrupt.
+    ///
+    /// The flow type is a combination of the constants in [`Type`].
+    fn set_type(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _irq_data: &mut LockedIrqData,
+        _flow_type: u32,
+    ) -> Result<ExtraResult> {
+        Ok(ExtraResult::None)
+    }
+
+    /// Enables or disables power-management wake-on of an interrupt.
+    fn set_wake(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _irq_data: &IrqData,
+        _on: bool,
+    ) -> Result {
+        Ok(())
+    }
+}
+
+/// Initialises `chip` with the callbacks defined in `T`.
+///
+/// # Safety
+///
+/// The caller must ensure that the value stored in the irq chip data is the result of calling
+/// [`PointerWrapper::into_pointer] for the [`T::Data`] type.
+pub(crate) unsafe fn init_chip<T: Chip>(chip: &mut bindings::irq_chip) {
+    chip.irq_ack = Some(irq_ack_callback::<T>);
+    chip.irq_mask = Some(irq_mask_callback::<T>);
+    chip.irq_unmask = Some(irq_unmask_callback::<T>);
+
+    if T::HAS_SET_TYPE {
+        chip.irq_set_type = Some(irq_set_type_callback::<T>);
+    }
+
+    if T::HAS_SET_WAKE {
+        chip.irq_set_wake = Some(irq_set_wake_callback::<T>);
+    }
+}
+
+/// Enables or disables power-management wake-on for the given irq number.
+pub fn set_wake(irq: u32, on: bool) -> Result {
+    // SAFETY: Just an FFI call, there are no extra requirements for safety.
+    let ret = unsafe { bindings::irq_set_irq_wake(irq, on as _) };
+    if ret < 0 {
+        Err(Error::from_kernel_errno(ret))
+    } else {
+        Ok(())
+    }
+}
+
+unsafe extern "C" fn irq_ack_callback<T: Chip>(irq_data: *mut bindings::irq_data) {
+    // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+    // callback, ensure that the value stored as irq chip data comes from a previous call to
+    // `PointerWrapper::into_pointer`.
+    let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+    // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+    // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+    T::ack(data, unsafe { &IrqData::from_ptr(irq_data) })
+}
+
+unsafe extern "C" fn irq_mask_callback<T: Chip>(irq_data: *mut bindings::irq_data) {
+    // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+    // callback, ensure that the value stored as irq chip data comes from a previous call to
+    // `PointerWrapper::into_pointer`.
+    let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+    // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+    // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+    T::mask(data, unsafe { &IrqData::from_ptr(irq_data) })
+}
+
+unsafe extern "C" fn irq_unmask_callback<T: Chip>(irq_data: *mut bindings::irq_data) {
+    // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+    // callback, ensure that the value stored as irq chip data comes from a previous call to
+    // `PointerWrapper::into_pointer`.
+    let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+    // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+    // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+    T::unmask(data, unsafe { &IrqData::from_ptr(irq_data) })
+}
+
+unsafe extern "C" fn irq_set_type_callback<T: Chip>(
+    irq_data: *mut bindings::irq_data,
+    flow_type: core::ffi::c_uint,
+) -> core::ffi::c_int {
+    from_kernel_result! {
+        // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+        // callback, ensure that the value stored as irq chip data comes from a previous call to
+        // `PointerWrapper::into_pointer`.
+        let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+        // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+        // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+        let ret = T::set_type(
+            data,
+            &mut LockedIrqData(unsafe { IrqData::from_ptr(irq_data) }),
+            flow_type,
+        )?;
+        Ok(ret as _)
+    }
+}
+
+unsafe extern "C" fn irq_set_wake_callback<T: Chip>(
+    irq_data: *mut bindings::irq_data,
+    on: core::ffi::c_uint,
+) -> core::ffi::c_int {
+    from_kernel_result! {
+        // SAFETY: The safety requirements of `init_chip`, which is the only place that uses this
+        // callback, ensure that the value stored as irq chip data comes from a previous call to
+        // `PointerWrapper::into_pointer`.
+        let data = unsafe { T::Data::borrow(bindings::irq_data_get_irq_chip_data(irq_data)) };
+
+        // SAFETY: The value returned by `IrqData` is only valid until the end of this function, and
+        // `irq_data` is guaranteed to be valid until then (by the contract with C code).
+        T::set_wake(data, unsafe { &IrqData::from_ptr(irq_data) }, on != 0)?;
+        Ok(0)
+    }
+}
+
+/// Contains constants that describes how an interrupt can be triggered.
+///
+/// It is tagged with `non_exhaustive` to prevent users from instantiating it.
+#[non_exhaustive]
+pub struct Type;
+
+impl Type {
+    /// The interrupt cannot be triggered.
+    pub const NONE: u32 = bindings::IRQ_TYPE_NONE;
+
+    /// The interrupt is triggered when the signal goes from low to high.
+    pub const EDGE_RISING: u32 = bindings::IRQ_TYPE_EDGE_RISING;
+
+    /// The interrupt is triggered when the signal goes from high to low.
+    pub const EDGE_FALLING: u32 = bindings::IRQ_TYPE_EDGE_FALLING;
+
+    /// The interrupt is triggered when the signal goes from low to high and when it goes to high
+    /// to low.
+    pub const EDGE_BOTH: u32 = bindings::IRQ_TYPE_EDGE_BOTH;
+
+    /// The interrupt is triggered while the signal is held high.
+    pub const LEVEL_HIGH: u32 = bindings::IRQ_TYPE_LEVEL_HIGH;
+
+    /// The interrupt is triggered while the signal is held low.
+    pub const LEVEL_LOW: u32 = bindings::IRQ_TYPE_LEVEL_LOW;
+}
+
+/// Wraps the kernel's `struct irq_desc`.
+///
+/// # Invariants
+///
+/// The pointer `Descriptor::ptr` is non-null and valid.
+pub struct Descriptor {
+    pub(crate) ptr: *mut bindings::irq_desc,
+}
+
+impl Descriptor {
+    /// Constructs a new `struct irq_desc` wrapper.
+    ///
+    /// # Safety
+    ///
+    /// The pointer `ptr` must be non-null and valid for the lifetime of the returned object.
+    unsafe fn from_ptr(ptr: *mut bindings::irq_desc) -> Self {
+        // INVARIANT: The safety requirements ensure the invariant.
+        Self { ptr }
+    }
+
+    /// Calls `chained_irq_enter` and returns a guard that calls `chained_irq_exit` once dropped.
+    ///
+    /// It is meant to be used by chained irq handlers to dispatch irqs to the next handlers.
+    pub fn enter_chained(&self) -> ChainedGuard<'_> {
+        // SAFETY: By the type invariants, `ptr` is always non-null and valid.
+        let irq_chip = unsafe { bindings::irq_desc_get_chip(self.ptr) };
+
+        // SAFETY: By the type invariants, `ptr` is always non-null and valid. `irq_chip` was just
+        // returned from `ptr`, so it is still valid too.
+        unsafe { bindings::chained_irq_enter(irq_chip, self.ptr) };
+        ChainedGuard {
+            desc: self,
+            irq_chip,
+        }
+    }
+}
+
+struct InternalRegistration<T: PointerWrapper> {
+    irq: u32,
+    data: *mut core::ffi::c_void,
+    name: CString,
+    _p: PhantomData<T>,
+}
+
+impl<T: PointerWrapper> InternalRegistration<T> {
+    /// Registers a new irq handler.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `handler` and `thread_fn` are compatible with the registration,
+    /// that is, that they only use their second argument while the call is happening and that they
+    /// only call [`T::borrow`] on it (e.g., they shouldn't call [`T::from_pointer`] and consume
+    /// it).
+    unsafe fn try_new(
+        irq: core::ffi::c_uint,
+        handler: bindings::irq_handler_t,
+        thread_fn: bindings::irq_handler_t,
+        flags: usize,
+        data: T,
+        name: fmt::Arguments<'_>,
+    ) -> Result<Self> {
+        let ptr = data.into_pointer() as *mut _;
+        let name = CString::try_from_fmt(name)?;
+        let guard = ScopeGuard::new(|| {
+            // SAFETY: `ptr` came from a previous call to `into_pointer`.
+            unsafe { T::from_pointer(ptr) };
+        });
+        // SAFETY: `name` and `ptr` remain valid as long as the registration is alive.
+        to_result(unsafe {
+            bindings::request_threaded_irq(
+                irq,
+                handler,
+                thread_fn,
+                flags as _,
+                name.as_char_ptr(),
+                ptr,
+            )
+        })?;
+        guard.dismiss();
+        Ok(Self {
+            irq,
+            name,
+            data: ptr,
+            _p: PhantomData,
+        })
+    }
+}
+
+impl<T: PointerWrapper> Drop for InternalRegistration<T> {
+    fn drop(&mut self) {
+        // Unregister irq handler.
+        //
+        // SAFETY: When `try_new` succeeds, the irq was successfully requested, so it is ok to free
+        // it here.
+        unsafe { bindings::free_irq(self.irq, self.data) };
+
+        // Free context data.
+        //
+        // SAFETY: This matches the call to `into_pointer` from `try_new` in the success case.
+        unsafe { T::from_pointer(self.data) };
+    }
+}
+
+/// An irq handler.
+pub trait Handler {
+    /// The context data associated with and made available to the handler.
+    type Data: PointerWrapper;
+
+    /// Called from interrupt context when the irq happens.
+    fn handle_irq(data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Return;
+}
+
+/// The registration of an interrupt handler.
+///
+/// # Examples
+///
+/// The following is an example of a regular handler with a boxed `u32` as data.
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::irq;
+///
+/// struct Example;
+///
+/// impl irq::Handler for Example {
+///     type Data = Box<u32>;
+///
+///     fn handle_irq(_data: &u32) -> irq::Return {
+///         irq::Return::None
+///     }
+/// }
+///
+/// fn request_irq(irq: u32, data: Box<u32>) -> Result<irq::Registration<Example>> {
+///     irq::Registration::try_new(irq, data, irq::flags::SHARED, fmt!("example_{irq}"))
+/// }
+/// ```
+pub struct Registration<H: Handler>(InternalRegistration<H::Data>);
+
+impl<H: Handler> Registration<H> {
+    /// Registers a new irq handler.
+    ///
+    /// The valid values of `flags` come from the [`flags`] module.
+    pub fn try_new(
+        irq: u32,
+        data: H::Data,
+        flags: usize,
+        name: fmt::Arguments<'_>,
+    ) -> Result<Self> {
+        // SAFETY: `handler` only calls `H::Data::borrow` on `raw_data`.
+        Ok(Self(unsafe {
+            InternalRegistration::try_new(irq, Some(Self::handler), None, flags, data, name)?
+        }))
+    }
+
+    unsafe extern "C" fn handler(
+        _irq: core::ffi::c_int,
+        raw_data: *mut core::ffi::c_void,
+    ) -> bindings::irqreturn_t {
+        // SAFETY: On registration, `into_pointer` was called, so it is safe to borrow from it here
+        // because `from_pointer` is called only after the irq is unregistered.
+        let data = unsafe { H::Data::borrow(raw_data) };
+        H::handle_irq(data) as _
+    }
+}
+
+/// A threaded irq handler.
+pub trait ThreadedHandler {
+    /// The context data associated with and made available to the handlers.
+    type Data: PointerWrapper;
+
+    /// Called from interrupt context when the irq first happens.
+    fn handle_primary_irq(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Return {
+        Return::WakeThread
+    }
+
+    /// Called from the handler thread.
+    fn handle_threaded_irq(data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Return;
+}
+
+/// The registration of a threaded interrupt handler.
+///
+/// # Examples
+///
+/// The following is an example of a threaded handler with a ref-counted u32 as data:
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::{
+///     irq,
+///     sync::{Ref, RefBorrow},
+/// };
+///
+/// struct Example;
+///
+/// impl irq::ThreadedHandler for Example {
+///     type Data = Ref<u32>;
+///
+///     fn handle_threaded_irq(_data: RefBorrow<'_, u32>) -> irq::Return {
+///         irq::Return::None
+///     }
+/// }
+///
+/// fn request_irq(irq: u32, data: Ref<u32>) -> Result<irq::ThreadedRegistration<Example>> {
+///     irq::ThreadedRegistration::try_new(irq, data, irq::flags::SHARED, fmt!("example_{irq}"))
+/// }
+/// ```
+pub struct ThreadedRegistration<H: ThreadedHandler>(InternalRegistration<H::Data>);
+
+impl<H: ThreadedHandler> ThreadedRegistration<H> {
+    /// Registers a new threaded irq handler.
+    ///
+    /// The valid values of `flags` come from the [`flags`] module.
+    pub fn try_new(
+        irq: u32,
+        data: H::Data,
+        flags: usize,
+        name: fmt::Arguments<'_>,
+    ) -> Result<Self> {
+        // SAFETY: both `primary_handler` and `threaded_handler` only call `H::Data::borrow` on
+        // `raw_data`.
+        Ok(Self(unsafe {
+            InternalRegistration::try_new(
+                irq,
+                Some(Self::primary_handler),
+                Some(Self::threaded_handler),
+                flags,
+                data,
+                name,
+            )?
+        }))
+    }
+
+    unsafe extern "C" fn primary_handler(
+        _irq: core::ffi::c_int,
+        raw_data: *mut core::ffi::c_void,
+    ) -> bindings::irqreturn_t {
+        // SAFETY: On registration, `into_pointer` was called, so it is safe to borrow from it here
+        // because `from_pointer` is called only after the irq is unregistered.
+        let data = unsafe { H::Data::borrow(raw_data) };
+        H::handle_primary_irq(data) as _
+    }
+
+    unsafe extern "C" fn threaded_handler(
+        _irq: core::ffi::c_int,
+        raw_data: *mut core::ffi::c_void,
+    ) -> bindings::irqreturn_t {
+        // SAFETY: On registration, `into_pointer` was called, so it is safe to borrow from it here
+        // because `from_pointer` is called only after the irq is unregistered.
+        let data = unsafe { H::Data::borrow(raw_data) };
+        H::handle_threaded_irq(data) as _
+    }
+}
+
+/// The return value from interrupt handlers.
+pub enum Return {
+    /// The interrupt was not from this device or was not handled.
+    None = bindings::irqreturn_IRQ_NONE as _,
+
+    /// The interrupt was handled by this device.
+    Handled = bindings::irqreturn_IRQ_HANDLED as _,
+
+    /// The handler wants the handler thread to wake up.
+    WakeThread = bindings::irqreturn_IRQ_WAKE_THREAD as _,
+}
+
+/// Container for interrupt flags.
+pub mod flags {
+    use crate::bindings;
+
+    /// Use the interrupt line as already configured.
+    pub const TRIGGER_NONE: usize = bindings::IRQF_TRIGGER_NONE as _;
+
+    /// The interrupt is triggered when the signal goes from low to high.
+    pub const TRIGGER_RISING: usize = bindings::IRQF_TRIGGER_RISING as _;
+
+    /// The interrupt is triggered when the signal goes from high to low.
+    pub const TRIGGER_FALLING: usize = bindings::IRQF_TRIGGER_FALLING as _;
+
+    /// The interrupt is triggered while the signal is held high.
+    pub const TRIGGER_HIGH: usize = bindings::IRQF_TRIGGER_HIGH as _;
+
+    /// The interrupt is triggered while the signal is held low.
+    pub const TRIGGER_LOW: usize = bindings::IRQF_TRIGGER_LOW as _;
+
+    /// Allow sharing the irq among several devices.
+    pub const SHARED: usize = bindings::IRQF_SHARED as _;
+
+    /// Set by callers when they expect sharing mismatches to occur.
+    pub const PROBE_SHARED: usize = bindings::IRQF_PROBE_SHARED as _;
+
+    /// Flag to mark this interrupt as timer interrupt.
+    pub const TIMER: usize = bindings::IRQF_TIMER as _;
+
+    /// Interrupt is per cpu.
+    pub const PERCPU: usize = bindings::IRQF_PERCPU as _;
+
+    /// Flag to exclude this interrupt from irq balancing.
+    pub const NOBALANCING: usize = bindings::IRQF_NOBALANCING as _;
+
+    /// Interrupt is used for polling (only the interrupt that is registered first in a shared
+    /// interrupt is considered for performance reasons).
+    pub const IRQPOLL: usize = bindings::IRQF_IRQPOLL as _;
+
+    /// Interrupt is not reenabled after the hardirq handler finished. Used by threaded interrupts
+    /// which need to keep the irq line disabled until the threaded handler has been run.
+    pub const ONESHOT: usize = bindings::IRQF_ONESHOT as _;
+
+    /// Do not disable this IRQ during suspend. Does not guarantee that this interrupt will wake
+    /// the system from a suspended state.
+    pub const NO_SUSPEND: usize = bindings::IRQF_NO_SUSPEND as _;
+
+    /// Force enable it on resume even if [`NO_SUSPEND`] is set.
+    pub const FORCE_RESUME: usize = bindings::IRQF_FORCE_RESUME as _;
+
+    /// Interrupt cannot be threaded.
+    pub const NO_THREAD: usize = bindings::IRQF_NO_THREAD as _;
+
+    /// Resume IRQ early during syscore instead of at device resume time.
+    pub const EARLY_RESUME: usize = bindings::IRQF_EARLY_RESUME as _;
+
+    /// If the IRQ is shared with a NO_SUSPEND user, execute this interrupt handler after
+    /// suspending interrupts. For system wakeup devices users need to implement wakeup detection
+    /// in their interrupt handlers.
+    pub const COND_SUSPEND: usize = bindings::IRQF_COND_SUSPEND as _;
+
+    /// Don't enable IRQ or NMI automatically when users request it. Users will enable it
+    /// explicitly by `enable_irq` or `enable_nmi` later.
+    pub const NO_AUTOEN: usize = bindings::IRQF_NO_AUTOEN as _;
+
+    /// Exclude from runnaway detection for IPI and similar handlers, depends on `PERCPU`.
+    pub const NO_DEBUG: usize = bindings::IRQF_NO_DEBUG as _;
+}
+
+/// A guard to call `chained_irq_exit` after `chained_irq_enter` was called.
+///
+/// It is also used as evidence that a previous `chained_irq_enter` was called. So there are no
+/// public constructors and it is only created after indeed calling `chained_irq_enter`.
+pub struct ChainedGuard<'a> {
+    desc: &'a Descriptor,
+    irq_chip: *mut bindings::irq_chip,
+}
+
+impl Drop for ChainedGuard<'_> {
+    fn drop(&mut self) {
+        // SAFETY: The lifetime of `ChainedGuard` guarantees that `self.desc` remains valid, so it
+        // also guarantess `irq_chip` (which was returned from it) and `self.desc.ptr` (guaranteed
+        // by the type invariants).
+        unsafe { bindings::chained_irq_exit(self.irq_chip, self.desc.ptr) };
+    }
+}
+
+/// Wraps the kernel's `struct irq_domain`.
+///
+/// # Invariants
+///
+/// The pointer `Domain::ptr` is non-null and valid.
+#[cfg(CONFIG_IRQ_DOMAIN)]
+pub struct Domain {
+    ptr: *mut bindings::irq_domain,
+}
+
+#[cfg(CONFIG_IRQ_DOMAIN)]
+impl Domain {
+    /// Constructs a new `struct irq_domain` wrapper.
+    ///
+    /// # Safety
+    ///
+    /// The pointer `ptr` must be non-null and valid for the lifetime of the returned object.
+    pub(crate) unsafe fn from_ptr(ptr: *mut bindings::irq_domain) -> Self {
+        // INVARIANT: The safety requirements ensure the invariant.
+        Self { ptr }
+    }
+
+    /// Invokes the chained handler of the given hw irq of the given domain.
+    ///
+    /// It requires evidence that `chained_irq_enter` was called, which is done by passing a
+    /// `ChainedGuard` instance.
+    pub fn generic_handle_chained(&self, hwirq: u32, _guard: &ChainedGuard<'_>) {
+        // SAFETY: `ptr` is valid by the type invariants.
+        unsafe { bindings::generic_handle_domain_irq(self.ptr, hwirq) };
+    }
+}
+
+/// A high-level irq flow handler.
+pub trait FlowHandler {
+    /// The data associated with the handler.
+    type Data: PointerWrapper;
+
+    /// Implements the irq flow for the given descriptor.
+    fn handle_irq_flow(data: <Self::Data as PointerWrapper>::Borrowed<'_>, desc: &Descriptor);
+}
+
+/// Returns the raw irq flow handler corresponding to the (high-level) one defined in `T`.
+///
+/// # Safety
+///
+/// The caller must ensure that the value stored in the irq handler data (as returned by
+/// `irq_desc_get_handler_data`) is the result of calling [`PointerWrapper::into_pointer] for the
+/// [`T::Data`] type.
+pub(crate) unsafe fn new_flow_handler<T: FlowHandler>() -> bindings::irq_flow_handler_t {
+    Some(irq_flow_handler::<T>)
+}
+
+unsafe extern "C" fn irq_flow_handler<T: FlowHandler>(desc: *mut bindings::irq_desc) {
+    // SAFETY: By the safety requirements of `new_flow_handler`, we know that the value returned by
+    // `irq_desc_get_handler_data` comes from calling `T::Data::into_pointer`. `desc` is valid by
+    // the C API contract.
+    let data = unsafe { T::Data::borrow(bindings::irq_desc_get_handler_data(desc)) };
+
+    // SAFETY: The C API guarantees that `desc` is valid for the duration of this call, which
+    // outlives the lifetime returned by `from_desc`.
+    T::handle_irq_flow(data, &unsafe { Descriptor::from_ptr(desc) });
+}
diff --git a/rust/kernel/kasync.rs b/rust/kernel/kasync.rs
new file mode 100644
index 000000000000..d48e9041e804
--- /dev/null
+++ b/rust/kernel/kasync.rs
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel async functionality.
+
+use core::{
+    future::Future,
+    pin::Pin,
+    task::{Context, Poll},
+};
+
+pub mod executor;
+#[cfg(CONFIG_NET)]
+pub mod net;
+
+/// Yields execution of the current task so that other tasks may execute.
+///
+/// The task continues to be in a "runnable" state though, so it will eventually run again.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::kasync::yield_now;
+///
+/// async fn example() {
+///     pr_info!("Before yield\n");
+///     yield_now().await;
+///     pr_info!("After yield\n");
+/// }
+/// ```
+pub fn yield_now() -> impl Future<Output = ()> {
+    struct Yield {
+        first_poll: bool,
+    }
+
+    impl Future for Yield {
+        type Output = ();
+
+        fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> {
+            if !self.first_poll {
+                Poll::Ready(())
+            } else {
+                self.first_poll = false;
+                cx.waker().wake_by_ref();
+                Poll::Pending
+            }
+        }
+    }
+
+    Yield { first_poll: true }
+}
diff --git a/rust/kernel/kasync/executor.rs b/rust/kernel/kasync/executor.rs
new file mode 100644
index 000000000000..e8e55dcfdf35
--- /dev/null
+++ b/rust/kernel/kasync/executor.rs
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel support for executing futures.
+
+use crate::{
+    sync::{LockClassKey, Ref, RefBorrow},
+    types::PointerWrapper,
+    Result,
+};
+use core::{
+    future::Future,
+    task::{RawWaker, RawWakerVTable, Waker},
+};
+
+pub mod workqueue;
+
+/// Spawns a new task to run in the given executor.
+///
+/// It also automatically defines a new lockdep lock class for executors (e.g., workqueue) that
+/// require one.
+#[macro_export]
+macro_rules! spawn_task {
+    ($executor:expr, $task:expr) => {{
+        static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        $crate::kasync::executor::Executor::spawn($executor, &CLASS, $task)
+    }};
+}
+
+/// A task spawned in an executor.
+pub trait Task {
+    /// Synchronously stops the task.
+    ///
+    /// It ensures that the task won't run again and releases resources needed to run the task
+    /// (e.g., the closure is dropped). If the task is inflight, it waits for the task to block or
+    /// complete before cleaning up and returning.
+    ///
+    /// Callers must not call this from within the task itself as it will likely lead to a
+    /// deadlock.
+    fn sync_stop(self: Ref<Self>);
+}
+
+/// An environment for executing tasks.
+pub trait Executor: Sync + Send {
+    /// Starts executing a task defined by the given future.
+    ///
+    /// Callers are encouraged to use the [`spawn_task`] macro because it automatically defines a
+    /// new lock class key.
+    fn spawn(
+        self: RefBorrow<'_, Self>,
+        lock_class_key: &'static LockClassKey,
+        future: impl Future + 'static + Send,
+    ) -> Result<Ref<dyn Task>>
+    where
+        Self: Sized;
+
+    /// Stops the executor.
+    ///
+    /// After it is called, attempts to spawn new tasks will result in an error and existing ones
+    /// won't be polled anymore.
+    fn stop(&self);
+}
+
+/// A waker that is wrapped in [`Ref`] for its reference counting.
+///
+/// Types that implement this trait can get a [`Waker`] by calling [`ref_waker`].
+pub trait RefWake: Send + Sync {
+    /// Wakes a task up.
+    fn wake_by_ref(self: RefBorrow<'_, Self>);
+
+    /// Wakes a task up and consumes a reference.
+    fn wake(self: Ref<Self>) {
+        self.as_ref_borrow().wake_by_ref();
+    }
+}
+
+/// Creates a [`Waker`] from a [`Ref<T>`], where `T` implements the [`RefWake`] trait.
+pub fn ref_waker<T: 'static + RefWake>(w: Ref<T>) -> Waker {
+    fn raw_waker<T: 'static + RefWake>(w: Ref<T>) -> RawWaker {
+        let data = w.into_pointer();
+        RawWaker::new(
+            data.cast(),
+            &RawWakerVTable::new(clone::<T>, wake::<T>, wake_by_ref::<T>, drop::<T>),
+        )
+    }
+
+    unsafe fn clone<T: 'static + RefWake>(ptr: *const ()) -> RawWaker {
+        // SAFETY: The data stored in the raw waker is the result of a call to `into_pointer`.
+        let w = unsafe { Ref::<T>::borrow(ptr.cast()) };
+        raw_waker(w.into())
+    }
+
+    unsafe fn wake<T: 'static + RefWake>(ptr: *const ()) {
+        // SAFETY: The data stored in the raw waker is the result of a call to `into_pointer`.
+        let w = unsafe { Ref::<T>::from_pointer(ptr.cast()) };
+        w.wake();
+    }
+
+    unsafe fn wake_by_ref<T: 'static + RefWake>(ptr: *const ()) {
+        // SAFETY: The data stored in the raw waker is the result of a call to `into_pointer`.
+        let w = unsafe { Ref::<T>::borrow(ptr.cast()) };
+        w.wake_by_ref();
+    }
+
+    unsafe fn drop<T: 'static + RefWake>(ptr: *const ()) {
+        // SAFETY: The data stored in the raw waker is the result of a call to `into_pointer`.
+        unsafe { Ref::<T>::from_pointer(ptr.cast()) };
+    }
+
+    let raw = raw_waker(w);
+    // SAFETY: The vtable of the raw waker satisfy the behaviour requirements of a waker.
+    unsafe { Waker::from_raw(raw) }
+}
+
+/// A handle to an executor that automatically stops it on drop.
+pub struct AutoStopHandle<T: Executor + ?Sized> {
+    executor: Option<Ref<T>>,
+}
+
+impl<T: Executor + ?Sized> AutoStopHandle<T> {
+    /// Creates a new instance of an [`AutoStopHandle`].
+    pub fn new(executor: Ref<T>) -> Self {
+        Self {
+            executor: Some(executor),
+        }
+    }
+
+    /// Detaches from the auto-stop handle.
+    ///
+    /// That is, extracts the executor from the handle and doesn't stop it anymore.
+    pub fn detach(mut self) -> Ref<T> {
+        self.executor.take().unwrap()
+    }
+
+    /// Returns the executor associated with the auto-stop handle.
+    ///
+    /// This is so that callers can, for example, spawn new tasks.
+    pub fn executor(&self) -> RefBorrow<'_, T> {
+        self.executor.as_ref().unwrap().as_ref_borrow()
+    }
+}
+
+impl<T: Executor + ?Sized> Drop for AutoStopHandle<T> {
+    fn drop(&mut self) {
+        if let Some(ex) = self.executor.take() {
+            ex.stop();
+        }
+    }
+}
+
+impl<T: 'static + Executor> From<AutoStopHandle<T>> for AutoStopHandle<dyn Executor> {
+    fn from(src: AutoStopHandle<T>) -> Self {
+        Self::new(src.detach())
+    }
+}
diff --git a/rust/kernel/kasync/executor/workqueue.rs b/rust/kernel/kasync/executor/workqueue.rs
new file mode 100644
index 000000000000..81cd16880600
--- /dev/null
+++ b/rust/kernel/kasync/executor/workqueue.rs
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel support for executing futures in C workqueues (`struct workqueue_struct`).
+
+use super::{AutoStopHandle, RefWake};
+use crate::{
+    error::code::*,
+    mutex_init,
+    revocable::AsyncRevocable,
+    sync::{LockClassKey, Mutex, Ref, RefBorrow, UniqueRef},
+    unsafe_list,
+    workqueue::{BoxedQueue, Queue, Work, WorkAdapter},
+    Either, Left, Result, Right,
+};
+use core::{cell::UnsafeCell, future::Future, marker::PhantomPinned, pin::Pin, task::Context};
+
+trait RevocableTask {
+    fn revoke(&self);
+    fn flush(self: Ref<Self>);
+    fn to_links(&self) -> &unsafe_list::Links<dyn RevocableTask>;
+}
+
+// SAFETY: `Task` has a single `links` field and only one adapter.
+unsafe impl unsafe_list::Adapter for dyn RevocableTask {
+    type EntryType = dyn RevocableTask;
+    fn to_links(obj: &dyn RevocableTask) -> &unsafe_list::Links<dyn RevocableTask> {
+        obj.to_links()
+    }
+}
+
+struct Task<T: 'static + Send + Future> {
+    links: unsafe_list::Links<dyn RevocableTask>,
+    executor: Ref<Executor>,
+    work: Work,
+    future: AsyncRevocable<UnsafeCell<T>>,
+}
+
+// SAFETY: The `future` field is only used by one thread at a time (in the `poll` method, which is
+// called by the work queue, who guarantees no reentrancy), so a task is `Sync` as long as the
+// future is `Send`.
+unsafe impl<T: 'static + Send + Future> Sync for Task<T> {}
+
+// SAFETY: If the future `T` is `Send`, so is the task.
+unsafe impl<T: 'static + Send + Future> Send for Task<T> {}
+
+impl<T: 'static + Send + Future> Task<T> {
+    fn try_new(
+        executor: Ref<Executor>,
+        key: &'static LockClassKey,
+        future: T,
+    ) -> Result<Ref<Self>> {
+        let task = UniqueRef::try_new(Self {
+            executor: executor.clone(),
+            links: unsafe_list::Links::new(),
+            // SAFETY: `work` is initialised below.
+            work: unsafe { Work::new() },
+            future: AsyncRevocable::new(UnsafeCell::new(future)),
+        })?;
+
+        Work::init(&task, key);
+
+        let task = Ref::from(task);
+
+        // Add task to list.
+        {
+            let mut guard = executor.inner.lock();
+            if guard.stopped {
+                return Err(EINVAL);
+            }
+
+            // Convert one reference into a pointer so that we hold on to a ref count while the
+            // task is in the list.
+            Ref::into_raw(task.clone());
+
+            // SAFETY: The task was just created, so it is not in any other lists. It remains alive
+            // because we incremented the refcount to account for it being in the list. It never
+            // moves because it's pinned behind a `Ref`.
+            unsafe { guard.tasks.push_back(&*task) };
+        }
+
+        Ok(task)
+    }
+}
+
+unsafe impl<T: 'static + Send + Future> WorkAdapter for Task<T> {
+    type Target = Self;
+    const FIELD_OFFSET: isize = crate::offset_of!(Self, work);
+    fn run(task: Ref<Task<T>>) {
+        let waker = super::ref_waker(task.clone());
+        let mut ctx = Context::from_waker(&waker);
+
+        let guard = if let Some(g) = task.future.try_access() {
+            g
+        } else {
+            return;
+        };
+
+        // SAFETY: `future` is pinned when the task is. The task is pinned because it's behind a
+        // `Ref`, which is always pinned.
+        //
+        // Work queues guarantee no reentrancy and this is the only place where the future is
+        // dereferenced, so it's ok to do it mutably.
+        let future = unsafe { Pin::new_unchecked(&mut *guard.get()) };
+        if future.poll(&mut ctx).is_ready() {
+            drop(guard);
+            task.revoke();
+        }
+    }
+}
+
+impl<T: 'static + Send + Future> super::Task for Task<T> {
+    fn sync_stop(self: Ref<Self>) {
+        self.revoke();
+        self.flush();
+    }
+}
+
+impl<T: 'static + Send + Future> RevocableTask for Task<T> {
+    fn revoke(&self) {
+        if !self.future.revoke() {
+            // Nothing to do if the task was already revoked.
+            return;
+        }
+
+        // SAFETY: The object is inserted into the list on creation and only removed when the
+        // future is first revoked. (Subsequent revocations don't result in additional attempts
+        // to remove per the check above.)
+        unsafe { self.executor.inner.lock().tasks.remove(self) };
+
+        // Decrement the refcount now that the task is no longer in the list.
+        //
+        // SAFETY: `into_raw` was called from `try_new` when the task was added to the list.
+        unsafe { Ref::from_raw(self) };
+    }
+
+    fn flush(self: Ref<Self>) {
+        self.work.cancel();
+    }
+
+    fn to_links(&self) -> &unsafe_list::Links<dyn RevocableTask> {
+        &self.links
+    }
+}
+
+impl<T: 'static + Send + Future> RefWake for Task<T> {
+    fn wake(self: Ref<Self>) {
+        if self.future.is_revoked() {
+            return;
+        }
+
+        match &self.executor.queue {
+            Left(q) => &**q,
+            Right(q) => *q,
+        }
+        .enqueue(self.clone());
+    }
+
+    fn wake_by_ref(self: RefBorrow<'_, Self>) {
+        Ref::from(self).wake();
+    }
+}
+
+struct ExecutorInner {
+    stopped: bool,
+    tasks: unsafe_list::List<dyn RevocableTask>,
+}
+
+/// An executor backed by a work queue.
+///
+/// # Examples
+///
+/// The following example runs two tasks on the shared system workqueue.
+///
+/// ```
+/// # use kernel::prelude::*;
+/// use kernel::kasync::executor::workqueue::Executor;
+/// use kernel::spawn_task;
+/// use kernel::workqueue;
+///
+/// fn example_shared_workqueue() -> Result {
+///     let mut handle = Executor::try_new(workqueue::system())?;
+///     spawn_task!(handle.executor(), async {
+///         pr_info!("First workqueue task\n");
+///     })?;
+///     spawn_task!(handle.executor(), async {
+///         pr_info!("Second workqueue task\n");
+///     })?;
+///     handle.detach();
+///     Ok(())
+/// }
+///
+/// # example_shared_workqueue().unwrap();
+/// ```
+pub struct Executor {
+    queue: Either<BoxedQueue, &'static Queue>,
+    inner: Mutex<ExecutorInner>,
+    _pin: PhantomPinned,
+}
+
+// SAFETY: The executor is backed by a kernel `struct workqueue_struct`, which works from any
+// thread.
+unsafe impl Send for Executor {}
+
+// SAFETY: The executor is backed by a kernel `struct workqueue_struct`, which can be used
+// concurrently by multiple threads.
+unsafe impl Sync for Executor {}
+
+impl Executor {
+    /// Creates a new workqueue-based executor using a static work queue.
+    pub fn try_new(wq: &'static Queue) -> Result<AutoStopHandle<Self>> {
+        Self::new_internal(Right(wq))
+    }
+
+    /// Creates a new workqueue-based executor using an owned (boxed) work queue.
+    pub fn try_new_owned(wq: BoxedQueue) -> Result<AutoStopHandle<Self>> {
+        Self::new_internal(Left(wq))
+    }
+
+    /// Creates a new workqueue-based executor.
+    ///
+    /// It uses the given work queue to run its tasks.
+    fn new_internal(queue: Either<BoxedQueue, &'static Queue>) -> Result<AutoStopHandle<Self>> {
+        let mut e = Pin::from(UniqueRef::try_new(Self {
+            queue,
+            _pin: PhantomPinned,
+            // SAFETY: `mutex_init` is called below.
+            inner: unsafe {
+                Mutex::new(ExecutorInner {
+                    stopped: false,
+                    tasks: unsafe_list::List::new(),
+                })
+            },
+        })?);
+        // SAFETY: `tasks` is pinned when the executor is.
+        let pinned = unsafe { e.as_mut().map_unchecked_mut(|e| &mut e.inner) };
+        mutex_init!(pinned, "Executor::inner");
+
+        Ok(AutoStopHandle::new(e.into()))
+    }
+}
+
+impl super::Executor for Executor {
+    fn spawn(
+        self: RefBorrow<'_, Self>,
+        key: &'static LockClassKey,
+        future: impl Future + 'static + Send,
+    ) -> Result<Ref<dyn super::Task>> {
+        let task = Task::try_new(self.into(), key, future)?;
+        task.clone().wake();
+        Ok(task)
+    }
+
+    fn stop(&self) {
+        // Set the `stopped` flag.
+        self.inner.lock().stopped = true;
+
+        // Go through all tasks and revoke & flush them.
+        //
+        // N.B. If we decide to allow "asynchronous" stops, we need to ensure that tasks that have
+        // been revoked but not flushed yet remain in the list so that we can flush them here.
+        // Otherwise we may have a race where we may have a running task (was revoked while
+        // running) that isn't the list anymore, so we think we've synchronously stopped all tasks
+        // when we haven't really -- unloading a module in this situation leads to memory safety
+        // issues (running unloaded code).
+        loop {
+            let guard = self.inner.lock();
+
+            let front = if let Some(t) = guard.tasks.front() {
+                t
+            } else {
+                break;
+            };
+
+            // Get a new reference to the task.
+            //
+            // SAFETY: We know all entries in the list are of type `Ref<dyn RevocableTask>` and
+            // that a reference exists while the entry is in the list, and since we are holding the
+            // list lock, we know it cannot go away. The `into_raw` call below ensures that we
+            // don't decrement the refcount accidentally.
+            let tasktmp = unsafe { Ref::<dyn RevocableTask>::from_raw(front.as_ptr()) };
+            let task = tasktmp.clone();
+            Ref::into_raw(tasktmp);
+
+            // Release the mutex before revoking the task.
+            drop(guard);
+
+            task.revoke();
+            task.flush();
+        }
+    }
+}
diff --git a/rust/kernel/kasync/net.rs b/rust/kernel/kasync/net.rs
new file mode 100644
index 000000000000..b4bbeffad94a
--- /dev/null
+++ b/rust/kernel/kasync/net.rs
@@ -0,0 +1,322 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Async networking.
+
+use crate::{bindings, error::code::*, net, sync::NoWaitLock, types::Opaque, Result};
+use core::{
+    future::Future,
+    marker::{PhantomData, PhantomPinned},
+    ops::Deref,
+    pin::Pin,
+    task::{Context, Poll, Waker},
+};
+
+/// A socket listening on a TCP port.
+///
+/// The [`TcpListener::accept`] method is meant to be used in async contexts.
+pub struct TcpListener {
+    listener: net::TcpListener,
+}
+
+impl TcpListener {
+    /// Creates a new TCP listener.
+    ///
+    /// It is configured to listen on the given socket address for the given namespace.
+    pub fn try_new(ns: &net::Namespace, addr: &net::SocketAddr) -> Result<Self> {
+        Ok(Self {
+            listener: net::TcpListener::try_new(ns, addr)?,
+        })
+    }
+
+    /// Accepts a new connection.
+    ///
+    /// Returns a future that when ready indicates the result of the accept operation; on success,
+    /// it contains the newly-accepted tcp stream.
+    pub fn accept(&self) -> impl Future<Output = Result<TcpStream>> + '_ {
+        SocketFuture::from_listener(
+            self,
+            bindings::BINDINGS_EPOLLIN | bindings::BINDINGS_EPOLLERR,
+            || {
+                Ok(TcpStream {
+                    stream: self.listener.accept(false)?,
+                })
+            },
+        )
+    }
+}
+
+impl Deref for TcpListener {
+    type Target = net::TcpListener;
+
+    fn deref(&self) -> &Self::Target {
+        &self.listener
+    }
+}
+
+/// A connected TCP socket.
+///
+/// The potentially blocking methods (e.g., [`TcpStream::read`], [`TcpStream::write`]) are meant
+/// to be used in async contexts.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::prelude::*;
+/// # use kernel::kasync::net::TcpStream;
+/// async fn echo_server(stream: TcpStream) -> Result {
+///     let mut buf = [0u8; 1024];
+///     loop {
+///         let n = stream.read(&mut buf).await?;
+///         if n == 0 {
+///             return Ok(());
+///         }
+///         stream.write_all(&buf[..n]).await?;
+///     }
+/// }
+/// ```
+pub struct TcpStream {
+    stream: net::TcpStream,
+}
+
+impl TcpStream {
+    /// Reads data from a connected socket.
+    ///
+    /// Returns a future that when ready indicates the result of the read operation; on success, it
+    /// contains the number of bytes read, which will be zero if the connection is closed.
+    pub fn read<'a>(&'a self, buf: &'a mut [u8]) -> impl Future<Output = Result<usize>> + 'a {
+        SocketFuture::from_stream(
+            self,
+            bindings::BINDINGS_EPOLLIN | bindings::BINDINGS_EPOLLHUP | bindings::BINDINGS_EPOLLERR,
+            || self.stream.read(buf, false),
+        )
+    }
+
+    /// Writes data to the connected socket.
+    ///
+    /// Returns a future that when ready indicates the result of the write operation; on success, it
+    /// contains the number of bytes written.
+    pub fn write<'a>(&'a self, buf: &'a [u8]) -> impl Future<Output = Result<usize>> + 'a {
+        SocketFuture::from_stream(
+            self,
+            bindings::BINDINGS_EPOLLOUT | bindings::BINDINGS_EPOLLHUP | bindings::BINDINGS_EPOLLERR,
+            || self.stream.write(buf, false),
+        )
+    }
+
+    /// Writes all the data to the connected socket.
+    ///
+    /// Returns a future that when ready indicates the result of the write operation; on success, it
+    /// has written all the data.
+    pub async fn write_all<'a>(&'a self, buf: &'a [u8]) -> Result {
+        let mut rem = buf;
+
+        while !rem.is_empty() {
+            let n = self.write(rem).await?;
+            rem = &rem[n..];
+        }
+
+        Ok(())
+    }
+}
+
+impl Deref for TcpStream {
+    type Target = net::TcpStream;
+
+    fn deref(&self) -> &Self::Target {
+        &self.stream
+    }
+}
+
+/// A future for a socket operation.
+///
+/// # Invariants
+///
+/// `sock` is always non-null and valid for the duration of the lifetime of the instance.
+struct SocketFuture<'a, Out, F: FnMut() -> Result<Out> + Send + 'a> {
+    sock: *mut bindings::socket,
+    mask: u32,
+    is_queued: bool,
+    wq_entry: Opaque<bindings::wait_queue_entry>,
+    waker: NoWaitLock<Option<Waker>>,
+    _p: PhantomData<&'a ()>,
+    _pin: PhantomPinned,
+    operation: F,
+}
+
+// SAFETY: A kernel socket can be used from any thread, `wq_entry` is only used on drop and when
+// `is_queued` is initially `false`.
+unsafe impl<Out, F: FnMut() -> Result<Out> + Send> Send for SocketFuture<'_, Out, F> {}
+
+impl<'a, Out, F: FnMut() -> Result<Out> + Send + 'a> SocketFuture<'a, Out, F> {
+    /// Creates a new socket future.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `sock` is non-null, valid, and remains valid for the lifetime
+    /// (`'a`) of the returned instance.
+    unsafe fn new(sock: *mut bindings::socket, mask: u32, operation: F) -> Self {
+        Self {
+            sock,
+            mask,
+            is_queued: false,
+            wq_entry: Opaque::uninit(),
+            waker: NoWaitLock::new(None),
+            operation,
+            _p: PhantomData,
+            _pin: PhantomPinned,
+        }
+    }
+
+    /// Creates a new socket future for a tcp listener.
+    fn from_listener(listener: &'a TcpListener, mask: u32, operation: F) -> Self {
+        // SAFETY: The socket is guaranteed to remain valid because it is bound to the reference to
+        // the listener (whose existence guarantees the socket remains valid).
+        unsafe { Self::new(listener.listener.sock, mask, operation) }
+    }
+
+    /// Creates a new socket future for a tcp stream.
+    fn from_stream(stream: &'a TcpStream, mask: u32, operation: F) -> Self {
+        // SAFETY: The socket is guaranteed to remain valid because it is bound to the reference to
+        // the stream (whose existence guarantees the socket remains valid).
+        unsafe { Self::new(stream.stream.sock, mask, operation) }
+    }
+
+    /// Callback called when the socket changes state.
+    ///
+    /// If the state matches the one we're waiting on, we wake up the task so that the future can be
+    /// polled again.
+    unsafe extern "C" fn wake_callback(
+        wq_entry: *mut bindings::wait_queue_entry,
+        _mode: core::ffi::c_uint,
+        _flags: core::ffi::c_int,
+        key: *mut core::ffi::c_void,
+    ) -> core::ffi::c_int {
+        let mask = key as u32;
+
+        // SAFETY: The future is valid while this callback is called because we remove from the
+        // queue on drop.
+        //
+        // There is a potential soundness issue here because we're generating a shared reference to
+        // `Self` while `Self::poll` has a mutable (unique) reference. However, for `!Unpin` types
+        // (like `Self`), `&mut T` is treated as `*mut T` per
+        // <https://github.com/rust-lang/rust/issues/63818> -- so we avoid the unsoundness. Once a
+        // more definitive solution is available, we can change this to use it.
+        let s = unsafe { &*crate::container_of!(wq_entry, Self, wq_entry) };
+        if mask & s.mask == 0 {
+            // Nothing to do as this notification doesn't interest us.
+            return 0;
+        }
+
+        // If we can't acquire the waker lock, the waker is in the process of being modified. Our
+        // attempt to acquire the lock will be reported to the lock owner, so it will trigger the
+        // wake up.
+        if let Some(guard) = s.waker.try_lock() {
+            if let Some(ref w) = *guard {
+                let cloned = w.clone();
+                drop(guard);
+                cloned.wake();
+                return 1;
+            }
+        }
+        0
+    }
+
+    /// Poll the future once.
+    ///
+    /// It calls the operation and converts `EAGAIN` errors into a pending state.
+    fn poll_once(self: Pin<&mut Self>) -> Poll<Result<Out>> {
+        // SAFETY: We never move out of `this`.
+        let this = unsafe { self.get_unchecked_mut() };
+        match (this.operation)() {
+            Ok(s) => Poll::Ready(Ok(s)),
+            Err(e) => {
+                if e == EAGAIN {
+                    Poll::Pending
+                } else {
+                    Poll::Ready(Err(e))
+                }
+            }
+        }
+    }
+
+    /// Updates the waker stored in the future.
+    ///
+    /// It automatically triggers a wake up on races with the reactor.
+    fn set_waker(&self, waker: &Waker) {
+        if let Some(mut guard) = self.waker.try_lock() {
+            let old = core::mem::replace(&mut *guard, Some(waker.clone()));
+            let contention = guard.unlock();
+            drop(old);
+            if !contention {
+                return;
+            }
+        }
+
+        // We either couldn't store the waker because the existing one is being awakened, or the
+        // reactor tried to acquire the lock while we held it (contention). In either case, we just
+        // wake it up to ensure we don't miss any notification.
+        waker.wake_by_ref();
+    }
+}
+
+impl<Out, F: FnMut() -> Result<Out> + Send> Future for SocketFuture<'_, Out, F> {
+    type Output = Result<Out>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        match self.as_mut().poll_once() {
+            Poll::Ready(r) => Poll::Ready(r),
+            Poll::Pending => {
+                // Store away the latest waker every time we may `Pending`.
+                self.set_waker(cx.waker());
+                if self.is_queued {
+                    // Nothing else to do was the waiter is already queued.
+                    return Poll::Pending;
+                }
+
+                // SAFETY: We never move out of `this`.
+                let this = unsafe { self.as_mut().get_unchecked_mut() };
+
+                this.is_queued = true;
+
+                // SAFETY: `wq_entry` is valid for write.
+                unsafe {
+                    bindings::init_waitqueue_func_entry(
+                        this.wq_entry.get(),
+                        Some(Self::wake_callback),
+                    )
+                };
+
+                // SAFETY: `wq_entry` was just initialised above and is valid for read/write.
+                // By the type invariants, the socket is always valid.
+                unsafe {
+                    bindings::add_wait_queue(
+                        core::ptr::addr_of_mut!((*this.sock).wq.wait),
+                        this.wq_entry.get(),
+                    )
+                };
+
+                // If the future wasn't queued yet, we need to poll again in case it reached
+                // the desired state between the last poll and being queued (in which case we
+                // would have missed the notification).
+                self.poll_once()
+            }
+        }
+    }
+}
+
+impl<Out, F: FnMut() -> Result<Out> + Send> Drop for SocketFuture<'_, Out, F> {
+    fn drop(&mut self) {
+        if !self.is_queued {
+            return;
+        }
+
+        // SAFETY: `wq_entry` is initialised because `is_queued` is set to `true`, so it is valid
+        // for read/write. By the type invariants, the socket is always valid.
+        unsafe {
+            bindings::remove_wait_queue(
+                core::ptr::addr_of_mut!((*self.sock).wq.wait),
+                self.wq_entry.get(),
+            )
+        };
+    }
+}
diff --git a/rust/kernel/kunit.rs b/rust/kernel/kunit.rs
new file mode 100644
index 000000000000..5f3e102962c3
--- /dev/null
+++ b/rust/kernel/kunit.rs
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! KUnit-based macros for Rust unit tests.
+//!
+//! C header: [`include/kunit/test.h`](../../../../../include/kunit/test.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/dev-tools/kunit/index.html>
+
+/// Asserts that a boolean expression is `true` at runtime.
+///
+/// Public but hidden since it should only be used from generated tests.
+///
+/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
+/// facilities. See [`assert!`] for more details.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! kunit_assert {
+    ($test:expr, $cond:expr $(,)?) => {{
+        if !$cond {
+            #[repr(transparent)]
+            struct Location($crate::bindings::kunit_loc);
+
+            #[repr(transparent)]
+            struct UnaryAssert($crate::bindings::kunit_unary_assert);
+
+            // SAFETY: There is only a static instance and in that one the pointer field
+            // points to an immutable C string.
+            unsafe impl Sync for Location {}
+
+            // SAFETY: There is only a static instance and in that one the pointer field
+            // points to an immutable C string.
+            unsafe impl Sync for UnaryAssert {}
+
+            static FILE: &'static $crate::str::CStr = $crate::c_str!(core::file!());
+            static LOCATION: Location = Location($crate::bindings::kunit_loc {
+                file: FILE.as_char_ptr(),
+                line: core::line!() as i32,
+            });
+            static CONDITION: &'static $crate::str::CStr = $crate::c_str!(stringify!($cond));
+            static ASSERTION: UnaryAssert = UnaryAssert($crate::bindings::kunit_unary_assert {
+                assert: $crate::bindings::kunit_assert {
+                    format: Some($crate::bindings::kunit_unary_assert_format),
+                },
+                condition: CONDITION.as_char_ptr(),
+                expected_true: true,
+            });
+
+            // SAFETY:
+            //   - FFI call.
+            //   - The `test` pointer is valid because this hidden macro should only be called by
+            //     the generated documentation tests which forward the test pointer given by KUnit.
+            //   - The string pointers (`file` and `condition`) point to null-terminated ones.
+            //   - The function pointer (`format`) points to the proper function.
+            //   - The pointers passed will remain valid since they point to statics.
+            //   - The format string is allowed to be null.
+            //   - There are, however, problems with this: first of all, this will end up stopping
+            //     the thread, without running destructors. While that is problematic in itself,
+            //     it is considered UB to have what is effectively an forced foreign unwind
+            //     with `extern "C"` ABI. One could observe the stack that is now gone from
+            //     another thread. We should avoid pinning stack variables to prevent library UB,
+            //     too. For the moment, given test failures are reported immediately before the
+            //     next test runs, that test failures should be fixed and that KUnit is explicitly
+            //     documented as not suitable for production environments, we feel it is reasonable.
+            unsafe {
+                $crate::bindings::kunit_do_failed_assertion(
+                    $test,
+                    core::ptr::addr_of!(LOCATION.0),
+                    $crate::bindings::kunit_assert_type_KUNIT_ASSERTION,
+                    core::ptr::addr_of!(ASSERTION.0.assert),
+                    core::ptr::null(),
+                );
+            }
+        }
+    }};
+}
+
+/// Asserts that two expressions are equal to each other (using [`PartialEq`]).
+///
+/// Public but hidden since it should only be used from generated tests.
+///
+/// Unlike the one in `core`, this one does not panic; instead, it is mapped to the KUnit
+/// facilities. See [`assert!`] for more details.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! kunit_assert_eq {
+    ($test:expr, $left:expr, $right:expr $(,)?) => {{
+        // For the moment, we just forward to the expression assert because,
+        // for binary asserts, KUnit supports only a few types (e.g. integers).
+        $crate::kunit_assert!($test, $left == $right);
+    }};
+}
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
new file mode 100644
index 000000000000..b55fe00761c2
--- /dev/null
+++ b/rust/kernel/lib.rs
@@ -0,0 +1,267 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! The `kernel` crate.
+//!
+//! This crate contains the kernel APIs that have been ported or wrapped for
+//! usage by Rust code in the kernel and is shared by all of them.
+//!
+//! In other words, all the rest of the Rust code in the kernel (e.g. kernel
+//! modules written in Rust) depends on [`core`], [`alloc`] and this crate.
+//!
+//! If you need a kernel C API that is not ported or wrapped yet here, then
+//! do so first instead of bypassing this crate.
+
+#![no_std]
+#![feature(allocator_api)]
+#![feature(associated_type_defaults)]
+#![feature(coerce_unsized)]
+#![feature(const_mut_refs)]
+#![feature(const_ptr_offset_from)]
+#![feature(const_refs_to_cell)]
+#![feature(const_trait_impl)]
+#![feature(core_ffi_c)]
+#![feature(c_size_t)]
+#![feature(dispatch_from_dyn)]
+#![feature(doc_cfg)]
+#![feature(duration_constants)]
+#![feature(generic_associated_types)]
+#![feature(ptr_metadata)]
+#![feature(receiver_trait)]
+#![feature(unsize)]
+
+// Ensure conditional compilation based on the kernel configuration works;
+// otherwise we may silently break things like initcall handling.
+#[cfg(not(CONFIG_RUST))]
+compile_error!("Missing kernel configuration for conditional compilation");
+
+#[cfg(not(test))]
+#[cfg(not(testlib))]
+mod allocator;
+
+#[doc(hidden)]
+pub use bindings;
+
+pub use macros;
+
+#[cfg(CONFIG_ARM_AMBA)]
+pub mod amba;
+pub mod chrdev;
+#[cfg(CONFIG_COMMON_CLK)]
+pub mod clk;
+pub mod cred;
+pub mod delay;
+pub mod device;
+pub mod driver;
+pub mod error;
+pub mod file;
+pub mod fs;
+pub mod gpio;
+pub mod hwrng;
+pub mod irq;
+pub mod kasync;
+pub mod miscdev;
+pub mod mm;
+#[cfg(CONFIG_NET)]
+pub mod net;
+pub mod pages;
+pub mod power;
+pub mod revocable;
+pub mod security;
+pub mod str;
+pub mod task;
+pub mod workqueue;
+
+pub mod linked_list;
+mod raw_list;
+pub mod rbtree;
+pub mod unsafe_list;
+
+#[doc(hidden)]
+pub mod module_param;
+
+mod build_assert;
+pub mod prelude;
+pub mod print;
+pub mod random;
+mod static_assert;
+#[doc(hidden)]
+pub mod std_vendor;
+pub mod sync;
+
+#[cfg(any(CONFIG_SYSCTL, doc))]
+#[doc(cfg(CONFIG_SYSCTL))]
+pub mod sysctl;
+
+pub mod io_buffer;
+#[cfg(CONFIG_HAS_IOMEM)]
+pub mod io_mem;
+pub mod iov_iter;
+pub mod of;
+pub mod platform;
+mod types;
+pub mod user_ptr;
+
+#[cfg(CONFIG_KUNIT)]
+pub mod kunit;
+
+#[doc(hidden)]
+pub use build_error::build_error;
+
+pub use crate::error::{to_result, Error, Result};
+pub use crate::types::{
+    bit, bits_iter, ARef, AlwaysRefCounted, Bool, Either, Either::Left, Either::Right, False, Mode,
+    Opaque, PointerWrapper, ScopeGuard, True,
+};
+
+use core::marker::PhantomData;
+
+/// Page size defined in terms of the `PAGE_SHIFT` macro from C.
+///
+/// [`PAGE_SHIFT`]: ../../../include/asm-generic/page.h
+pub const PAGE_SIZE: usize = 1 << bindings::PAGE_SHIFT;
+
+/// Prefix to appear before log messages printed from within the kernel crate.
+const __LOG_PREFIX: &[u8] = b"rust_kernel\0";
+
+/// The top level entrypoint to implementing a kernel module.
+///
+/// For any teardown or cleanup operations, your type may implement [`Drop`].
+pub trait Module: Sized + Sync {
+    /// Called at module initialization time.
+    ///
+    /// Use this method to perform whatever setup or registration your module
+    /// should do.
+    ///
+    /// Equivalent to the `module_init` macro in the C API.
+    fn init(name: &'static str::CStr, module: &'static ThisModule) -> Result<Self>;
+}
+
+/// Equivalent to `THIS_MODULE` in the C API.
+///
+/// C header: `include/linux/export.h`
+pub struct ThisModule(*mut bindings::module);
+
+// SAFETY: `THIS_MODULE` may be used from all threads within a module.
+unsafe impl Sync for ThisModule {}
+
+impl ThisModule {
+    /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer.
+    ///
+    /// # Safety
+    ///
+    /// The pointer must be equal to the right `THIS_MODULE`.
+    pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule {
+        ThisModule(ptr)
+    }
+
+    /// Locks the module parameters to access them.
+    ///
+    /// Returns a [`KParamGuard`] that will release the lock when dropped.
+    pub fn kernel_param_lock(&self) -> KParamGuard<'_> {
+        // SAFETY: `kernel_param_lock` will check if the pointer is null and
+        // use the built-in mutex in that case.
+        #[cfg(CONFIG_SYSFS)]
+        unsafe {
+            bindings::kernel_param_lock(self.0)
+        }
+
+        KParamGuard {
+            #[cfg(CONFIG_SYSFS)]
+            this_module: self,
+            phantom: PhantomData,
+        }
+    }
+}
+
+/// Scoped lock on the kernel parameters of [`ThisModule`].
+///
+/// Lock will be released when this struct is dropped.
+pub struct KParamGuard<'a> {
+    #[cfg(CONFIG_SYSFS)]
+    this_module: &'a ThisModule,
+    phantom: PhantomData<&'a ()>,
+}
+
+#[cfg(CONFIG_SYSFS)]
+impl<'a> Drop for KParamGuard<'a> {
+    fn drop(&mut self) {
+        // SAFETY: `kernel_param_lock` will check if the pointer is null and
+        // use the built-in mutex in that case. The existence of `self`
+        // guarantees that the lock is held.
+        unsafe { bindings::kernel_param_unlock(self.this_module.0) }
+    }
+}
+
+/// Calculates the offset of a field from the beginning of the struct it belongs to.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::prelude::*;
+/// # use kernel::offset_of;
+/// struct Test {
+///     a: u64,
+///     b: u32,
+/// }
+///
+/// assert_eq!(offset_of!(Test, b), 8);
+/// ```
+#[macro_export]
+macro_rules! offset_of {
+    ($type:ty, $($f:tt)*) => {{
+        let tmp = core::mem::MaybeUninit::<$type>::uninit();
+        let outer = tmp.as_ptr();
+        // To avoid warnings when nesting `unsafe` blocks.
+        #[allow(unused_unsafe)]
+        // SAFETY: The pointer is valid and aligned, just not initialised; `addr_of` ensures that
+        // we don't actually read from `outer` (which would be UB) nor create an intermediate
+        // reference.
+        let inner = unsafe { core::ptr::addr_of!((*outer).$($f)*) } as *const u8;
+        // To avoid warnings when nesting `unsafe` blocks.
+        #[allow(unused_unsafe)]
+        // SAFETY: The two pointers are within the same allocation block.
+        unsafe { inner.offset_from(outer as *const u8) }
+    }}
+}
+
+/// Produces a pointer to an object from a pointer to one of its fields.
+///
+/// # Safety
+///
+/// Callers must ensure that the pointer to the field is in fact a pointer to the specified field,
+/// as opposed to a pointer to another object of the same type. If this condition is not met,
+/// any dereference of the resulting pointer is UB.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::container_of;
+/// struct Test {
+///     a: u64,
+///     b: u32,
+/// }
+///
+/// let test = Test { a: 10, b: 20 };
+/// let b_ptr = &test.b;
+/// let test_alias = container_of!(b_ptr, Test, b);
+/// assert!(core::ptr::eq(&test, test_alias));
+/// ```
+#[macro_export]
+macro_rules! container_of {
+    ($ptr:expr, $type:ty, $($f:tt)*) => {{
+        let ptr = $ptr as *const _ as *const u8;
+        let offset = $crate::offset_of!($type, $($f)*);
+        ptr.wrapping_offset(-offset) as *const $type
+    }}
+}
+
+#[cfg(not(any(testlib, test)))]
+#[panic_handler]
+fn panic(info: &core::panic::PanicInfo<'_>) -> ! {
+    pr_emerg!("{}\n", info);
+    // SAFETY: FFI call.
+    unsafe { bindings::BUG() };
+    // Bindgen currently does not recognize `__noreturn` so `BUG` returns `()`
+    // instead of `!`. See <https://github.com/rust-lang/rust-bindgen/issues/2094>.
+    loop {}
+}
diff --git a/rust/kernel/linked_list.rs b/rust/kernel/linked_list.rs
new file mode 100644
index 000000000000..3330edcc7ca8
--- /dev/null
+++ b/rust/kernel/linked_list.rs
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Linked lists.
+//!
+//! TODO: This module is a work in progress.
+
+use alloc::boxed::Box;
+use core::ptr::NonNull;
+
+pub use crate::raw_list::{Cursor, GetLinks, Links};
+use crate::{raw_list, raw_list::RawList, sync::Ref};
+
+// TODO: Use the one from `kernel::file_operations::PointerWrapper` instead.
+/// Wraps an object to be inserted in a linked list.
+pub trait Wrapper<T: ?Sized> {
+    /// Converts the wrapped object into a pointer that represents it.
+    fn into_pointer(self) -> NonNull<T>;
+
+    /// Converts the object back from the pointer representation.
+    ///
+    /// # Safety
+    ///
+    /// The passed pointer must come from a previous call to [`Wrapper::into_pointer()`].
+    unsafe fn from_pointer(ptr: NonNull<T>) -> Self;
+
+    /// Returns a reference to the wrapped object.
+    fn as_ref(&self) -> &T;
+}
+
+impl<T: ?Sized> Wrapper<T> for Box<T> {
+    fn into_pointer(self) -> NonNull<T> {
+        NonNull::new(Box::into_raw(self)).unwrap()
+    }
+
+    unsafe fn from_pointer(ptr: NonNull<T>) -> Self {
+        unsafe { Box::from_raw(ptr.as_ptr()) }
+    }
+
+    fn as_ref(&self) -> &T {
+        AsRef::as_ref(self)
+    }
+}
+
+impl<T: ?Sized> Wrapper<T> for Ref<T> {
+    fn into_pointer(self) -> NonNull<T> {
+        NonNull::new(Ref::into_raw(self) as _).unwrap()
+    }
+
+    unsafe fn from_pointer(ptr: NonNull<T>) -> Self {
+        // SAFETY: The safety requirements of `from_pointer` satisfy the ones from `Ref::from_raw`.
+        unsafe { Ref::from_raw(ptr.as_ptr() as _) }
+    }
+
+    fn as_ref(&self) -> &T {
+        AsRef::as_ref(self)
+    }
+}
+
+impl<T: ?Sized> Wrapper<T> for &T {
+    fn into_pointer(self) -> NonNull<T> {
+        NonNull::from(self)
+    }
+
+    unsafe fn from_pointer(ptr: NonNull<T>) -> Self {
+        unsafe { &*ptr.as_ptr() }
+    }
+
+    fn as_ref(&self) -> &T {
+        self
+    }
+}
+
+/// A descriptor of wrapped list elements.
+pub trait GetLinksWrapped: GetLinks {
+    /// Specifies which wrapper (e.g., `Box` and `Arc`) wraps the list entries.
+    type Wrapped: Wrapper<Self::EntryType>;
+}
+
+impl<T: ?Sized> GetLinksWrapped for Box<T>
+where
+    Box<T>: GetLinks,
+{
+    type Wrapped = Box<<Box<T> as GetLinks>::EntryType>;
+}
+
+impl<T: GetLinks + ?Sized> GetLinks for Box<T> {
+    type EntryType = T::EntryType;
+    fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+        <T as GetLinks>::get_links(data)
+    }
+}
+
+impl<T: ?Sized> GetLinksWrapped for Ref<T>
+where
+    Ref<T>: GetLinks,
+{
+    type Wrapped = Ref<<Ref<T> as GetLinks>::EntryType>;
+}
+
+impl<T: GetLinks + ?Sized> GetLinks for Ref<T> {
+    type EntryType = T::EntryType;
+
+    fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType> {
+        <T as GetLinks>::get_links(data)
+    }
+}
+
+/// A linked list.
+///
+/// Elements in the list are wrapped and ownership is transferred to the list while the element is
+/// in the list.
+pub struct List<G: GetLinksWrapped> {
+    list: RawList<G>,
+}
+
+impl<G: GetLinksWrapped> List<G> {
+    /// Constructs a new empty linked list.
+    pub fn new() -> Self {
+        Self {
+            list: RawList::new(),
+        }
+    }
+
+    /// Returns whether the list is empty.
+    pub fn is_empty(&self) -> bool {
+        self.list.is_empty()
+    }
+
+    /// Adds the given object to the end (back) of the list.
+    ///
+    /// It is dropped if it's already on this (or another) list; this can happen for
+    /// reference-counted objects, so dropping means decrementing the reference count.
+    pub fn push_back(&mut self, data: G::Wrapped) {
+        let ptr = data.into_pointer();
+
+        // SAFETY: We took ownership of the entry, so it is safe to insert it.
+        if !unsafe { self.list.push_back(ptr.as_ref()) } {
+            // If insertion failed, rebuild object so that it can be freed.
+            // SAFETY: We just called `into_pointer` above.
+            unsafe { G::Wrapped::from_pointer(ptr) };
+        }
+    }
+
+    /// Inserts the given object after `existing`.
+    ///
+    /// It is dropped if it's already on this (or another) list; this can happen for
+    /// reference-counted objects, so dropping means decrementing the reference count.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `existing` points to a valid entry that is on the list.
+    pub unsafe fn insert_after(&mut self, existing: NonNull<G::EntryType>, data: G::Wrapped) {
+        let ptr = data.into_pointer();
+        let entry = unsafe { &*existing.as_ptr() };
+        if unsafe { !self.list.insert_after(entry, ptr.as_ref()) } {
+            // If insertion failed, rebuild object so that it can be freed.
+            unsafe { G::Wrapped::from_pointer(ptr) };
+        }
+    }
+
+    /// Removes the given entry.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `data` is either on this list or in no list. It being on another
+    /// list leads to memory unsafety.
+    pub unsafe fn remove(&mut self, data: &G::Wrapped) -> Option<G::Wrapped> {
+        let entry_ref = Wrapper::as_ref(data);
+        if unsafe { self.list.remove(entry_ref) } {
+            Some(unsafe { G::Wrapped::from_pointer(NonNull::from(entry_ref)) })
+        } else {
+            None
+        }
+    }
+
+    /// Removes the element currently at the front of the list and returns it.
+    ///
+    /// Returns `None` if the list is empty.
+    pub fn pop_front(&mut self) -> Option<G::Wrapped> {
+        let front = self.list.pop_front()?;
+        // SAFETY: Elements on the list were inserted after a call to `into_pointer `.
+        Some(unsafe { G::Wrapped::from_pointer(front) })
+    }
+
+    /// Returns a cursor starting on the first (front) element of the list.
+    pub fn cursor_front(&self) -> Cursor<'_, G> {
+        self.list.cursor_front()
+    }
+
+    /// Returns a mutable cursor starting on the first (front) element of the list.
+    pub fn cursor_front_mut(&mut self) -> CursorMut<'_, G> {
+        CursorMut::new(self.list.cursor_front_mut())
+    }
+}
+
+impl<G: GetLinksWrapped> Default for List<G> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<G: GetLinksWrapped> Drop for List<G> {
+    fn drop(&mut self) {
+        while self.pop_front().is_some() {}
+    }
+}
+
+/// A list cursor that allows traversing a linked list and inspecting & mutating elements.
+pub struct CursorMut<'a, G: GetLinksWrapped> {
+    cursor: raw_list::CursorMut<'a, G>,
+}
+
+impl<'a, G: GetLinksWrapped> CursorMut<'a, G> {
+    fn new(cursor: raw_list::CursorMut<'a, G>) -> Self {
+        Self { cursor }
+    }
+
+    /// Returns the element the cursor is currently positioned on.
+    pub fn current(&mut self) -> Option<&mut G::EntryType> {
+        self.cursor.current()
+    }
+
+    /// Removes the element the cursor is currently positioned on.
+    ///
+    /// After removal, it advances the cursor to the next element.
+    pub fn remove_current(&mut self) -> Option<G::Wrapped> {
+        let ptr = self.cursor.remove_current()?;
+
+        // SAFETY: Elements on the list were inserted after a call to `into_pointer `.
+        Some(unsafe { G::Wrapped::from_pointer(ptr) })
+    }
+
+    /// Returns the element immediately after the one the cursor is positioned on.
+    pub fn peek_next(&mut self) -> Option<&mut G::EntryType> {
+        self.cursor.peek_next()
+    }
+
+    /// Returns the element immediately before the one the cursor is positioned on.
+    pub fn peek_prev(&mut self) -> Option<&mut G::EntryType> {
+        self.cursor.peek_prev()
+    }
+
+    /// Moves the cursor to the next element.
+    pub fn move_next(&mut self) {
+        self.cursor.move_next();
+    }
+}
diff --git a/rust/kernel/miscdev.rs b/rust/kernel/miscdev.rs
new file mode 100644
index 000000000000..65b95d6dba90
--- /dev/null
+++ b/rust/kernel/miscdev.rs
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Miscellaneous devices.
+//!
+//! C header: [`include/linux/miscdevice.h`](../../../../include/linux/miscdevice.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/driver-api/misc_devices.html>
+
+use crate::bindings;
+use crate::error::{code::*, Error, Result};
+use crate::file;
+use crate::{device, str::CStr, str::CString, ThisModule};
+use alloc::boxed::Box;
+use core::marker::PhantomPinned;
+use core::{fmt, mem::MaybeUninit, pin::Pin};
+
+/// Options which can be used to configure how a misc device is registered.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::{c_str, device::RawDevice, file, miscdev, prelude::*};
+/// fn example(
+///     reg: Pin<&mut miscdev::Registration<impl file::Operations<OpenData = ()>>>,
+///     parent: &dyn RawDevice,
+/// ) -> Result {
+///     miscdev::Options::new()
+///         .mode(0o600)
+///         .minor(10)
+///         .parent(parent)
+///         .register(reg, fmt!("sample"), ())
+/// }
+/// ```
+#[derive(Default)]
+pub struct Options<'a> {
+    minor: Option<i32>,
+    mode: Option<u16>,
+    parent: Option<&'a dyn device::RawDevice>,
+}
+
+impl<'a> Options<'a> {
+    /// Creates new [`Options`] instance with the required fields.
+    pub const fn new() -> Self {
+        Self {
+            minor: None,
+            mode: None,
+            parent: None,
+        }
+    }
+
+    /// Sets the minor device number.
+    pub const fn minor(&mut self, v: i32) -> &mut Self {
+        self.minor = Some(v);
+        self
+    }
+
+    /// Sets the device mode.
+    ///
+    /// This is usually an octal number and describes who can perform read/write/execute operations
+    /// on the device.
+    pub const fn mode(&mut self, m: u16) -> &mut Self {
+        self.mode = Some(m);
+        self
+    }
+
+    /// Sets the device parent.
+    pub const fn parent(&mut self, p: &'a dyn device::RawDevice) -> &mut Self {
+        self.parent = Some(p);
+        self
+    }
+
+    /// Registers a misc device using the configured options.
+    pub fn register<T: file::Operations>(
+        &self,
+        reg: Pin<&mut Registration<T>>,
+        name: fmt::Arguments<'_>,
+        open_data: T::OpenData,
+    ) -> Result {
+        reg.register_with_options(name, open_data, self)
+    }
+
+    /// Allocates a new registration of a misc device and completes the registration with the
+    /// configured options.
+    pub fn register_new<T: file::Operations>(
+        &self,
+        name: fmt::Arguments<'_>,
+        open_data: T::OpenData,
+    ) -> Result<Pin<Box<Registration<T>>>> {
+        let mut r = Pin::from(Box::try_new(Registration::new())?);
+        self.register(r.as_mut(), name, open_data)?;
+        Ok(r)
+    }
+}
+
+/// A registration of a miscellaneous device.
+///
+/// # Invariants
+///
+/// `Context` is always initialised when `registered` is `true`, and not initialised otherwise.
+pub struct Registration<T: file::Operations> {
+    registered: bool,
+    mdev: bindings::miscdevice,
+    name: Option<CString>,
+    _pin: PhantomPinned,
+
+    /// Context initialised on construction and made available to all file instances on
+    /// [`file::Operations::open`].
+    open_data: MaybeUninit<T::OpenData>,
+}
+
+impl<T: file::Operations> Registration<T> {
+    /// Creates a new [`Registration`] but does not register it yet.
+    ///
+    /// It is allowed to move.
+    pub fn new() -> Self {
+        // INVARIANT: `registered` is `false` and `open_data` is not initialised.
+        Self {
+            registered: false,
+            mdev: bindings::miscdevice::default(),
+            name: None,
+            _pin: PhantomPinned,
+            open_data: MaybeUninit::uninit(),
+        }
+    }
+
+    /// Registers a miscellaneous device.
+    ///
+    /// Returns a pinned heap-allocated representation of the registration.
+    pub fn new_pinned(name: fmt::Arguments<'_>, open_data: T::OpenData) -> Result<Pin<Box<Self>>> {
+        Options::new().register_new(name, open_data)
+    }
+
+    /// Registers a miscellaneous device with the rest of the kernel.
+    ///
+    /// It must be pinned because the memory block that represents the registration is
+    /// self-referential.
+    pub fn register(
+        self: Pin<&mut Self>,
+        name: fmt::Arguments<'_>,
+        open_data: T::OpenData,
+    ) -> Result {
+        Options::new().register(self, name, open_data)
+    }
+
+    /// Registers a miscellaneous device with the rest of the kernel. Additional optional settings
+    /// are provided via the `opts` parameter.
+    ///
+    /// It must be pinned because the memory block that represents the registration is
+    /// self-referential.
+    pub fn register_with_options(
+        self: Pin<&mut Self>,
+        name: fmt::Arguments<'_>,
+        open_data: T::OpenData,
+        opts: &Options<'_>,
+    ) -> Result {
+        // SAFETY: We must ensure that we never move out of `this`.
+        let this = unsafe { self.get_unchecked_mut() };
+        if this.registered {
+            // Already registered.
+            return Err(EINVAL);
+        }
+
+        let name = CString::try_from_fmt(name)?;
+
+        // SAFETY: The adapter is compatible with `misc_register`.
+        this.mdev.fops = unsafe { file::OperationsVtable::<Self, T>::build() };
+        this.mdev.name = name.as_char_ptr();
+        this.mdev.minor = opts.minor.unwrap_or(bindings::MISC_DYNAMIC_MINOR as i32);
+        this.mdev.mode = opts.mode.unwrap_or(0);
+        this.mdev.parent = opts
+            .parent
+            .map_or(core::ptr::null_mut(), |p| p.raw_device());
+
+        // We write to `open_data` here because as soon as `misc_register` succeeds, the file can be
+        // opened, so we need `open_data` configured ahead of time.
+        //
+        // INVARIANT: `registered` is set to `true`, but `open_data` is also initialised.
+        this.registered = true;
+        this.open_data.write(open_data);
+
+        let ret = unsafe { bindings::misc_register(&mut this.mdev) };
+        if ret < 0 {
+            // INVARIANT: `registered` is set back to `false` and the `open_data` is destructued.
+            this.registered = false;
+            // SAFETY: `open_data` was initialised a few lines above.
+            unsafe { this.open_data.assume_init_drop() };
+            return Err(Error::from_kernel_errno(ret));
+        }
+
+        this.name = Some(name);
+
+        Ok(())
+    }
+}
+
+impl<T: file::Operations> Default for Registration<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T: file::Operations> file::OpenAdapter<T::OpenData> for Registration<T> {
+    unsafe fn convert(
+        _inode: *mut bindings::inode,
+        file: *mut bindings::file,
+    ) -> *const T::OpenData {
+        // SAFETY: The caller must guarantee that `file` is valid.
+        let reg = crate::container_of!(unsafe { (*file).private_data }, Self, mdev);
+
+        // SAFETY: This function is only called while the misc device is still registered, so the
+        // registration must be valid. Additionally, the type invariants guarantee that while the
+        // miscdev is registered, `open_data` is initialised.
+        unsafe { (*reg).open_data.as_ptr() }
+    }
+}
+
+// SAFETY: The only method is `register()`, which requires a (pinned) mutable `Registration`, so it
+// is safe to pass `&Registration` to multiple threads because it offers no interior mutability.
+unsafe impl<T: file::Operations> Sync for Registration<T> {}
+
+// SAFETY: All functions work from any thread. So as long as the `Registration::open_data` is
+// `Send`, so is `Registration<T>`.
+unsafe impl<T: file::Operations> Send for Registration<T> where T::OpenData: Send {}
+
+impl<T: file::Operations> Drop for Registration<T> {
+    /// Removes the registration from the kernel if it has completed successfully before.
+    fn drop(&mut self) {
+        if self.registered {
+            // SAFETY: `registered` being `true` indicates that a previous call to  `misc_register`
+            // succeeded.
+            unsafe { bindings::misc_deregister(&mut self.mdev) };
+
+            // SAFETY: The type invariant guarantees that `open_data` is initialised when
+            // `registered` is `true`.
+            unsafe { self.open_data.assume_init_drop() };
+        }
+    }
+}
+
+/// Kernel module that exposes a single miscdev device implemented by `T`.
+pub struct Module<T: file::Operations<OpenData = ()>> {
+    _dev: Pin<Box<Registration<T>>>,
+}
+
+impl<T: file::Operations<OpenData = ()>> crate::Module for Module<T> {
+    fn init(name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        Ok(Self {
+            _dev: Registration::new_pinned(crate::fmt!("{name}"), ())?,
+        })
+    }
+}
+
+/// Declares a kernel module that exposes a single misc device.
+///
+/// The `type` argument should be a type which implements the [`FileOpener`] trait. Also accepts
+/// various forms of kernel metadata.
+///
+/// C header: [`include/linux/moduleparam.h`](../../../include/linux/moduleparam.h)
+///
+/// [`FileOpener`]: ../kernel/file_operations/trait.FileOpener.html
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::prelude::*;
+///
+/// module_misc_device! {
+///     type: MyFile,
+///     name: b"my_miscdev_kernel_module",
+///     author: b"Rust for Linux Contributors",
+///     description: b"My very own misc device kernel module!",
+///     license: b"GPL",
+/// }
+///
+/// #[derive(Default)]
+/// struct MyFile;
+///
+/// #[vtable]
+/// impl kernel::file::Operations for MyFile {}
+/// ```
+#[macro_export]
+macro_rules! module_misc_device {
+    (type: $type:ty, $($f:tt)*) => {
+        type ModuleType = kernel::miscdev::Module<$type>;
+        module! {
+            type: ModuleType,
+            $($f)*
+        }
+    }
+}
diff --git a/rust/kernel/mm.rs b/rust/kernel/mm.rs
new file mode 100644
index 000000000000..8a69c69dddd9
--- /dev/null
+++ b/rust/kernel/mm.rs
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Memory management.
+//!
+//! C header: [`include/linux/mm.h`](../../../../include/linux/mm.h)
+
+use crate::{bindings, pages, to_result, Result};
+
+/// Virtual memory.
+pub mod virt {
+    use super::*;
+
+    /// A wrapper for the kernel's `struct vm_area_struct`.
+    ///
+    /// It represents an area of virtual memory.
+    ///
+    /// # Invariants
+    ///
+    /// `vma` is always non-null and valid.
+    pub struct Area {
+        vma: *mut bindings::vm_area_struct,
+    }
+
+    impl Area {
+        /// Creates a new instance of a virtual memory area.
+        ///
+        /// # Safety
+        ///
+        /// Callers must ensure that `vma` is non-null and valid for the duration of the new area's
+        /// lifetime.
+        pub(crate) unsafe fn from_ptr(vma: *mut bindings::vm_area_struct) -> Self {
+            // INVARIANTS: The safety requirements guarantee the invariants.
+            Self { vma }
+        }
+
+        /// Returns the flags associated with the virtual memory area.
+        ///
+        /// The possible flags are a combination of the constants in [`flags`].
+        pub fn flags(&self) -> usize {
+            // SAFETY: `self.vma` is valid by the type invariants.
+            unsafe { (*self.vma).vm_flags as _ }
+        }
+
+        /// Sets the flags associated with the virtual memory area.
+        ///
+        /// The possible flags are a combination of the constants in [`flags`].
+        pub fn set_flags(&mut self, flags: usize) {
+            // SAFETY: `self.vma` is valid by the type invariants.
+            unsafe { (*self.vma).vm_flags = flags as _ };
+        }
+
+        /// Returns the start address of the virtual memory area.
+        pub fn start(&self) -> usize {
+            // SAFETY: `self.vma` is valid by the type invariants.
+            unsafe { (*self.vma).vm_start as _ }
+        }
+
+        /// Returns the end address of the virtual memory area.
+        pub fn end(&self) -> usize {
+            // SAFETY: `self.vma` is valid by the type invariants.
+            unsafe { (*self.vma).vm_end as _ }
+        }
+
+        /// Maps a single page at the given address within the virtual memory area.
+        pub fn insert_page(&mut self, address: usize, page: &pages::Pages<0>) -> Result {
+            // SAFETY: The page is guaranteed to be order 0 by the type system. The range of
+            // `address` is already checked by `vm_insert_page`. `self.vma` and `page.pages` are
+            // guaranteed by their repective type invariants to be valid.
+            to_result(unsafe { bindings::vm_insert_page(self.vma, address as _, page.pages) })
+        }
+    }
+
+    /// Container for [`Area`] flags.
+    pub mod flags {
+        use crate::bindings;
+
+        /// No flags are set.
+        pub const NONE: usize = bindings::VM_NONE as _;
+
+        /// Mapping allows reads.
+        pub const READ: usize = bindings::VM_READ as _;
+
+        /// Mapping allows writes.
+        pub const WRITE: usize = bindings::VM_WRITE as _;
+
+        /// Mapping allows execution.
+        pub const EXEC: usize = bindings::VM_EXEC as _;
+
+        /// Mapping is shared.
+        pub const SHARED: usize = bindings::VM_SHARED as _;
+
+        /// Mapping may be updated to allow reads.
+        pub const MAYREAD: usize = bindings::VM_MAYREAD as _;
+
+        /// Mapping may be updated to allow writes.
+        pub const MAYWRITE: usize = bindings::VM_MAYWRITE as _;
+
+        /// Mapping may be updated to allow execution.
+        pub const MAYEXEC: usize = bindings::VM_MAYEXEC as _;
+
+        /// Mapping may be updated to be shared.
+        pub const MAYSHARE: usize = bindings::VM_MAYSHARE as _;
+
+        /// Do not copy this vma on fork.
+        pub const DONTCOPY: usize = bindings::VM_DONTCOPY as _;
+
+        /// Cannot expand with mremap().
+        pub const DONTEXPAND: usize = bindings::VM_DONTEXPAND as _;
+
+        /// Lock the pages covered when they are faulted in.
+        pub const LOCKONFAULT: usize = bindings::VM_LOCKONFAULT as _;
+
+        /// Is a VM accounted object.
+        pub const ACCOUNT: usize = bindings::VM_ACCOUNT as _;
+
+        /// should the VM suppress accounting.
+        pub const NORESERVE: usize = bindings::VM_NORESERVE as _;
+
+        /// Huge TLB Page VM.
+        pub const HUGETLB: usize = bindings::VM_HUGETLB as _;
+
+        /// Synchronous page faults.
+        pub const SYNC: usize = bindings::VM_SYNC as _;
+
+        /// Architecture-specific flag.
+        pub const ARCH_1: usize = bindings::VM_ARCH_1 as _;
+
+        /// Wipe VMA contents in child..
+        pub const WIPEONFORK: usize = bindings::VM_WIPEONFORK as _;
+
+        /// Do not include in the core dump.
+        pub const DONTDUMP: usize = bindings::VM_DONTDUMP as _;
+
+        /// Not soft dirty clean area.
+        pub const SOFTDIRTY: usize = bindings::VM_SOFTDIRTY as _;
+
+        /// Can contain "struct page" and pure PFN pages.
+        pub const MIXEDMAP: usize = bindings::VM_MIXEDMAP as _;
+
+        /// MADV_HUGEPAGE marked this vma.
+        pub const HUGEPAGE: usize = bindings::VM_HUGEPAGE as _;
+
+        /// MADV_NOHUGEPAGE marked this vma.
+        pub const NOHUGEPAGE: usize = bindings::VM_NOHUGEPAGE as _;
+
+        /// KSM may merge identical pages.
+        pub const MERGEABLE: usize = bindings::VM_MERGEABLE as _;
+    }
+}
diff --git a/rust/kernel/module_param.rs b/rust/kernel/module_param.rs
new file mode 100644
index 000000000000..6df38c78c65c
--- /dev/null
+++ b/rust/kernel/module_param.rs
@@ -0,0 +1,499 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Types for module parameters.
+//!
+//! C header: [`include/linux/moduleparam.h`](../../../include/linux/moduleparam.h)
+
+use crate::error::{code::*, from_kernel_result};
+use crate::str::{CStr, Formatter};
+use core::fmt::Write;
+
+/// Types that can be used for module parameters.
+///
+/// Note that displaying the type in `sysfs` will fail if
+/// [`alloc::string::ToString::to_string`] (as implemented through the
+/// [`core::fmt::Display`] trait) writes more than [`PAGE_SIZE`]
+/// bytes (including an additional null terminator).
+///
+/// [`PAGE_SIZE`]: `crate::PAGE_SIZE`
+pub trait ModuleParam: core::fmt::Display + core::marker::Sized {
+    /// The `ModuleParam` will be used by the kernel module through this type.
+    ///
+    /// This may differ from `Self` if, for example, `Self` needs to track
+    /// ownership without exposing it or allocate extra space for other possible
+    /// parameter values. See [`StringParam`] or [`ArrayParam`] for examples.
+    type Value: ?Sized;
+
+    /// Whether the parameter is allowed to be set without an argument.
+    ///
+    /// Setting this to `true` allows the parameter to be passed without an
+    /// argument (e.g. just `module.param` instead of `module.param=foo`).
+    const NOARG_ALLOWED: bool;
+
+    /// Convert a parameter argument into the parameter value.
+    ///
+    /// `None` should be returned when parsing of the argument fails.
+    /// `arg == None` indicates that the parameter was passed without an
+    /// argument. If `NOARG_ALLOWED` is set to `false` then `arg` is guaranteed
+    /// to always be `Some(_)`.
+    ///
+    /// Parameters passed at boot time will be set before [`kmalloc`] is
+    /// available (even if the module is loaded at a later time). However, in
+    /// this case, the argument buffer will be valid for the entire lifetime of
+    /// the kernel. So implementations of this method which need to allocate
+    /// should first check that the allocator is available (with
+    /// [`crate::bindings::slab_is_available`]) and when it is not available
+    /// provide an alternative implementation which doesn't allocate. In cases
+    /// where the allocator is not available it is safe to save references to
+    /// `arg` in `Self`, but in other cases a copy should be made.
+    ///
+    /// [`kmalloc`]: ../../../include/linux/slab.h
+    fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self>;
+
+    /// Get the current value of the parameter for use in the kernel module.
+    ///
+    /// This function should not be used directly. Instead use the wrapper
+    /// `read` which will be generated by [`macros::module`].
+    fn value(&self) -> &Self::Value;
+
+    /// Set the module parameter from a string.
+    ///
+    /// Used to set the parameter value when loading the module or when set
+    /// through `sysfs`.
+    ///
+    /// # Safety
+    ///
+    /// If `val` is non-null then it must point to a valid null-terminated
+    /// string. The `arg` field of `param` must be an instance of `Self`.
+    unsafe extern "C" fn set_param(
+        val: *const core::ffi::c_char,
+        param: *const crate::bindings::kernel_param,
+    ) -> core::ffi::c_int {
+        let arg = if val.is_null() {
+            None
+        } else {
+            Some(unsafe { CStr::from_char_ptr(val).as_bytes() })
+        };
+        match Self::try_from_param_arg(arg) {
+            Some(new_value) => {
+                let old_value = unsafe { (*param).__bindgen_anon_1.arg as *mut Self };
+                let _ = unsafe { core::ptr::replace(old_value, new_value) };
+                0
+            }
+            None => EINVAL.to_kernel_errno(),
+        }
+    }
+
+    /// Write a string representation of the current parameter value to `buf`.
+    ///
+    /// Used for displaying the current parameter value in `sysfs`.
+    ///
+    /// # Safety
+    ///
+    /// `buf` must be a buffer of length at least `kernel::PAGE_SIZE` that is
+    /// writeable. The `arg` field of `param` must be an instance of `Self`.
+    unsafe extern "C" fn get_param(
+        buf: *mut core::ffi::c_char,
+        param: *const crate::bindings::kernel_param,
+    ) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: The C contracts guarantees that the buffer is at least `PAGE_SIZE` bytes.
+            let mut f = unsafe { Formatter::from_buffer(buf.cast(), crate::PAGE_SIZE) };
+            unsafe { write!(f, "{}\0", *((*param).__bindgen_anon_1.arg as *mut Self)) }?;
+            Ok(f.bytes_written().try_into()?)
+        }
+    }
+
+    /// Drop the parameter.
+    ///
+    /// Called when unloading a module.
+    ///
+    /// # Safety
+    ///
+    /// The `arg` field of `param` must be an instance of `Self`.
+    unsafe extern "C" fn free(arg: *mut core::ffi::c_void) {
+        unsafe { core::ptr::drop_in_place(arg as *mut Self) };
+    }
+}
+
+/// Trait for parsing integers.
+///
+/// Strings beginning with `0x`, `0o`, or `0b` are parsed as hex, octal, or
+/// binary respectively. Strings beginning with `0` otherwise are parsed as
+/// octal. Anything else is parsed as decimal. A leading `+` or `-` is also
+/// permitted. Any string parsed by [`kstrtol()`] or [`kstrtoul()`] will be
+/// successfully parsed.
+///
+/// [`kstrtol()`]: https://www.kernel.org/doc/html/latest/core-api/kernel-api.html#c.kstrtol
+/// [`kstrtoul()`]: https://www.kernel.org/doc/html/latest/core-api/kernel-api.html#c.kstrtoul
+trait ParseInt: Sized {
+    fn from_str_radix(src: &str, radix: u32) -> Result<Self, core::num::ParseIntError>;
+    fn checked_neg(self) -> Option<Self>;
+
+    fn from_str_unsigned(src: &str) -> Result<Self, core::num::ParseIntError> {
+        let (radix, digits) = if let Some(n) = src.strip_prefix("0x") {
+            (16, n)
+        } else if let Some(n) = src.strip_prefix("0X") {
+            (16, n)
+        } else if let Some(n) = src.strip_prefix("0o") {
+            (8, n)
+        } else if let Some(n) = src.strip_prefix("0O") {
+            (8, n)
+        } else if let Some(n) = src.strip_prefix("0b") {
+            (2, n)
+        } else if let Some(n) = src.strip_prefix("0B") {
+            (2, n)
+        } else if src.starts_with('0') {
+            (8, src)
+        } else {
+            (10, src)
+        };
+        Self::from_str_radix(digits, radix)
+    }
+
+    fn from_str(src: &str) -> Option<Self> {
+        match src.bytes().next() {
+            None => None,
+            Some(b'-') => Self::from_str_unsigned(&src[1..]).ok()?.checked_neg(),
+            Some(b'+') => Some(Self::from_str_unsigned(&src[1..]).ok()?),
+            Some(_) => Some(Self::from_str_unsigned(src).ok()?),
+        }
+    }
+}
+
+macro_rules! impl_parse_int {
+    ($ty:ident) => {
+        impl ParseInt for $ty {
+            fn from_str_radix(src: &str, radix: u32) -> Result<Self, core::num::ParseIntError> {
+                $ty::from_str_radix(src, radix)
+            }
+
+            fn checked_neg(self) -> Option<Self> {
+                self.checked_neg()
+            }
+        }
+    };
+}
+
+impl_parse_int!(i8);
+impl_parse_int!(u8);
+impl_parse_int!(i16);
+impl_parse_int!(u16);
+impl_parse_int!(i32);
+impl_parse_int!(u32);
+impl_parse_int!(i64);
+impl_parse_int!(u64);
+impl_parse_int!(isize);
+impl_parse_int!(usize);
+
+macro_rules! impl_module_param {
+    ($ty:ident) => {
+        impl ModuleParam for $ty {
+            type Value = $ty;
+
+            const NOARG_ALLOWED: bool = false;
+
+            fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self> {
+                let bytes = arg?;
+                let utf8 = core::str::from_utf8(bytes).ok()?;
+                <$ty as crate::module_param::ParseInt>::from_str(utf8)
+            }
+
+            fn value(&self) -> &Self::Value {
+                self
+            }
+        }
+    };
+}
+
+#[doc(hidden)]
+#[macro_export]
+/// Generate a static [`kernel_param_ops`](../../../include/linux/moduleparam.h) struct.
+///
+/// # Examples
+///
+/// ```ignore
+/// make_param_ops!(
+///     /// Documentation for new param ops.
+///     PARAM_OPS_MYTYPE, // Name for the static.
+///     MyType // A type which implements [`ModuleParam`].
+/// );
+/// ```
+macro_rules! make_param_ops {
+    ($ops:ident, $ty:ty) => {
+        $crate::make_param_ops!(
+            #[doc=""]
+            $ops,
+            $ty
+        );
+    };
+    ($(#[$meta:meta])* $ops:ident, $ty:ty) => {
+        $(#[$meta])*
+        ///
+        /// Static [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+        /// struct generated by [`make_param_ops`].
+        pub static $ops: $crate::bindings::kernel_param_ops = $crate::bindings::kernel_param_ops {
+            flags: if <$ty as $crate::module_param::ModuleParam>::NOARG_ALLOWED {
+                $crate::bindings::KERNEL_PARAM_OPS_FL_NOARG
+            } else {
+                0
+            },
+            set: Some(<$ty as $crate::module_param::ModuleParam>::set_param),
+            get: Some(<$ty as $crate::module_param::ModuleParam>::get_param),
+            free: Some(<$ty as $crate::module_param::ModuleParam>::free),
+        };
+    };
+}
+
+impl_module_param!(i8);
+impl_module_param!(u8);
+impl_module_param!(i16);
+impl_module_param!(u16);
+impl_module_param!(i32);
+impl_module_param!(u32);
+impl_module_param!(i64);
+impl_module_param!(u64);
+impl_module_param!(isize);
+impl_module_param!(usize);
+
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`i8`].
+    PARAM_OPS_I8,
+    i8
+);
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`u8`].
+    PARAM_OPS_U8,
+    u8
+);
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`i16`].
+    PARAM_OPS_I16,
+    i16
+);
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`u16`].
+    PARAM_OPS_U16,
+    u16
+);
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`i32`].
+    PARAM_OPS_I32,
+    i32
+);
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`u32`].
+    PARAM_OPS_U32,
+    u32
+);
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`i64`].
+    PARAM_OPS_I64,
+    i64
+);
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`u64`].
+    PARAM_OPS_U64,
+    u64
+);
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`isize`].
+    PARAM_OPS_ISIZE,
+    isize
+);
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`usize`].
+    PARAM_OPS_USIZE,
+    usize
+);
+
+impl ModuleParam for bool {
+    type Value = bool;
+
+    const NOARG_ALLOWED: bool = true;
+
+    fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self> {
+        match arg {
+            None => Some(true),
+            Some(b"y") | Some(b"Y") | Some(b"1") | Some(b"true") => Some(true),
+            Some(b"n") | Some(b"N") | Some(b"0") | Some(b"false") => Some(false),
+            _ => None,
+        }
+    }
+
+    fn value(&self) -> &Self::Value {
+        self
+    }
+}
+
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`bool`].
+    PARAM_OPS_BOOL,
+    bool
+);
+
+/// An array of at __most__ `N` values.
+///
+/// # Invariant
+///
+/// The first `self.used` elements of `self.values` are initialized.
+pub struct ArrayParam<T, const N: usize> {
+    values: [core::mem::MaybeUninit<T>; N],
+    used: usize,
+}
+
+impl<T, const N: usize> ArrayParam<T, { N }> {
+    fn values(&self) -> &[T] {
+        // SAFETY: The invariant maintained by `ArrayParam` allows us to cast
+        // the first `self.used` elements to `T`.
+        unsafe {
+            &*(&self.values[0..self.used] as *const [core::mem::MaybeUninit<T>] as *const [T])
+        }
+    }
+}
+
+impl<T: Copy, const N: usize> ArrayParam<T, { N }> {
+    const fn new() -> Self {
+        // INVARIANT: The first `self.used` elements of `self.values` are
+        // initialized.
+        ArrayParam {
+            values: [core::mem::MaybeUninit::uninit(); N],
+            used: 0,
+        }
+    }
+
+    const fn push(&mut self, val: T) {
+        if self.used < N {
+            // INVARIANT: The first `self.used` elements of `self.values` are
+            // initialized.
+            self.values[self.used] = core::mem::MaybeUninit::new(val);
+            self.used += 1;
+        }
+    }
+
+    /// Create an instance of `ArrayParam` initialized with `vals`.
+    ///
+    /// This function is only meant to be used in the [`module::module`] macro.
+    pub const fn create(vals: &[T]) -> Self {
+        let mut result = ArrayParam::new();
+        let mut i = 0;
+        while i < vals.len() {
+            result.push(vals[i]);
+            i += 1;
+        }
+        result
+    }
+}
+
+impl<T: core::fmt::Display, const N: usize> core::fmt::Display for ArrayParam<T, { N }> {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        for val in self.values() {
+            write!(f, "{},", val)?;
+        }
+        Ok(())
+    }
+}
+
+impl<T: Copy + core::fmt::Display + ModuleParam, const N: usize> ModuleParam
+    for ArrayParam<T, { N }>
+{
+    type Value = [T];
+
+    const NOARG_ALLOWED: bool = false;
+
+    fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self> {
+        arg.and_then(|args| {
+            let mut result = Self::new();
+            for arg in args.split(|b| *b == b',') {
+                result.push(T::try_from_param_arg(Some(arg))?);
+            }
+            Some(result)
+        })
+    }
+
+    fn value(&self) -> &Self::Value {
+        self.values()
+    }
+}
+
+/// A C-style string parameter.
+///
+/// The Rust version of the [`charp`] parameter. This type is meant to be
+/// used by the [`macros::module`] macro, not handled directly. Instead use the
+/// `read` method generated by that macro.
+///
+/// [`charp`]: ../../../include/linux/moduleparam.h
+pub enum StringParam {
+    /// A borrowed parameter value.
+    ///
+    /// Either the default value (which is static in the module) or borrowed
+    /// from the original argument buffer used to set the value.
+    Ref(&'static [u8]),
+
+    /// A value that was allocated when the parameter was set.
+    ///
+    /// The value needs to be freed when the parameter is reset or the module is
+    /// unloaded.
+    Owned(alloc::vec::Vec<u8>),
+}
+
+impl StringParam {
+    fn bytes(&self) -> &[u8] {
+        match self {
+            StringParam::Ref(bytes) => *bytes,
+            StringParam::Owned(vec) => &vec[..],
+        }
+    }
+}
+
+impl core::fmt::Display for StringParam {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        let bytes = self.bytes();
+        match core::str::from_utf8(bytes) {
+            Ok(utf8) => write!(f, "{}", utf8),
+            Err(_) => write!(f, "{:?}", bytes),
+        }
+    }
+}
+
+impl ModuleParam for StringParam {
+    type Value = [u8];
+
+    const NOARG_ALLOWED: bool = false;
+
+    fn try_from_param_arg(arg: Option<&'static [u8]>) -> Option<Self> {
+        // SAFETY: It is always safe to call [`slab_is_available`](../../../include/linux/slab.h).
+        let slab_available = unsafe { crate::bindings::slab_is_available() };
+        arg.and_then(|arg| {
+            if slab_available {
+                let mut vec = alloc::vec::Vec::new();
+                vec.try_extend_from_slice(arg).ok()?;
+                Some(StringParam::Owned(vec))
+            } else {
+                Some(StringParam::Ref(arg))
+            }
+        })
+    }
+
+    fn value(&self) -> &Self::Value {
+        self.bytes()
+    }
+}
+
+make_param_ops!(
+    /// Rust implementation of [`kernel_param_ops`](../../../include/linux/moduleparam.h)
+    /// for [`StringParam`].
+    PARAM_OPS_STR,
+    StringParam
+);
diff --git a/rust/kernel/net.rs b/rust/kernel/net.rs
new file mode 100644
index 000000000000..0115f3a35cd0
--- /dev/null
+++ b/rust/kernel/net.rs
@@ -0,0 +1,392 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Networking core.
+//!
+//! C headers: [`include/net/net_namespace.h`](../../../../include/linux/net/net_namespace.h),
+//! [`include/linux/netdevice.h`](../../../../include/linux/netdevice.h),
+//! [`include/linux/skbuff.h`](../../../../include/linux/skbuff.h).
+
+use crate::{bindings, str::CStr, to_result, ARef, AlwaysRefCounted, Error, Result};
+use core::{cell::UnsafeCell, ptr::NonNull};
+
+#[cfg(CONFIG_NETFILTER)]
+pub mod filter;
+
+/// Wraps the kernel's `struct net_device`.
+#[repr(transparent)]
+pub struct Device(UnsafeCell<bindings::net_device>);
+
+// SAFETY: Instances of `Device` are created on the C side. They are always refcounted.
+unsafe impl AlwaysRefCounted for Device {
+    fn inc_ref(&self) {
+        // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+        unsafe { bindings::dev_hold(self.0.get()) };
+    }
+
+    unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
+        // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+        unsafe { bindings::dev_put(obj.cast().as_ptr()) };
+    }
+}
+
+/// Wraps the kernel's `struct net`.
+#[repr(transparent)]
+pub struct Namespace(UnsafeCell<bindings::net>);
+
+impl Namespace {
+    /// Finds a network device with the given name in the namespace.
+    pub fn dev_get_by_name(&self, name: &CStr) -> Option<ARef<Device>> {
+        // SAFETY: The existence of a shared reference guarantees the refcount is nonzero.
+        let ptr =
+            NonNull::new(unsafe { bindings::dev_get_by_name(self.0.get(), name.as_char_ptr()) })?;
+        Some(unsafe { ARef::from_raw(ptr.cast()) })
+    }
+}
+
+// SAFETY: Instances of `Namespace` are created on the C side. They are always refcounted.
+unsafe impl AlwaysRefCounted for Namespace {
+    fn inc_ref(&self) {
+        // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+        unsafe { bindings::get_net(self.0.get()) };
+    }
+
+    unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
+        // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+        unsafe { bindings::put_net(obj.cast().as_ptr()) };
+    }
+}
+
+/// Returns the network namespace for the `init` process.
+pub fn init_ns() -> &'static Namespace {
+    unsafe { &*core::ptr::addr_of!(bindings::init_net).cast() }
+}
+
+/// Wraps the kernel's `struct sk_buff`.
+#[repr(transparent)]
+pub struct SkBuff(UnsafeCell<bindings::sk_buff>);
+
+impl SkBuff {
+    /// Creates a reference to an [`SkBuff`] from a valid pointer.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `ptr` is valid and remains valid for the lifetime of the
+    /// returned [`SkBuff`] instance.
+    pub unsafe fn from_ptr<'a>(ptr: *const bindings::sk_buff) -> &'a SkBuff {
+        // SAFETY: The safety requirements guarantee the validity of the dereference, while the
+        // `SkBuff` type being transparent makes the cast ok.
+        unsafe { &*ptr.cast() }
+    }
+
+    /// Returns the remaining data in the buffer's first segment.
+    pub fn head_data(&self) -> &[u8] {
+        // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+        let headlen = unsafe { bindings::skb_headlen(self.0.get()) };
+        let len = headlen.try_into().unwrap_or(usize::MAX);
+        // SAFETY: The existence of a shared reference means `self.0` is valid.
+        let data = unsafe { core::ptr::addr_of!((*self.0.get()).data).read() };
+        // SAFETY: The `struct sk_buff` conventions guarantee that at least `skb_headlen(skb)` bytes
+        // are valid from `skb->data`.
+        unsafe { core::slice::from_raw_parts(data, len) }
+    }
+
+    /// Returns the total length of the data (in all segments) in the skb.
+    #[allow(clippy::len_without_is_empty)]
+    pub fn len(&self) -> u32 {
+        // SAFETY: The existence of a shared reference means `self.0` is valid.
+        unsafe { core::ptr::addr_of!((*self.0.get()).len).read() }
+    }
+}
+
+// SAFETY: Instances of `SkBuff` are created on the C side. They are always refcounted.
+unsafe impl AlwaysRefCounted for SkBuff {
+    fn inc_ref(&self) {
+        // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+        unsafe { bindings::skb_get(self.0.get()) };
+    }
+
+    unsafe fn dec_ref(obj: core::ptr::NonNull<Self>) {
+        // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+        unsafe {
+            bindings::kfree_skb_reason(
+                obj.cast().as_ptr(),
+                bindings::skb_drop_reason_SKB_DROP_REASON_NOT_SPECIFIED,
+            )
+        };
+    }
+}
+
+/// An IPv4 address.
+///
+/// This is equivalent to C's `in_addr`.
+#[repr(transparent)]
+pub struct Ipv4Addr(bindings::in_addr);
+
+impl Ipv4Addr {
+    /// A wildcard IPv4 address.
+    ///
+    /// Binding to this address means binding to all IPv4 addresses.
+    pub const ANY: Self = Self::new(0, 0, 0, 0);
+
+    /// The IPv4 loopback address.
+    pub const LOOPBACK: Self = Self::new(127, 0, 0, 1);
+
+    /// The IPv4 broadcast address.
+    pub const BROADCAST: Self = Self::new(255, 255, 255, 255);
+
+    /// Creates a new IPv4 address with the given components.
+    pub const fn new(a: u8, b: u8, c: u8, d: u8) -> Self {
+        Self(bindings::in_addr {
+            s_addr: u32::from_be_bytes([a, b, c, d]).to_be(),
+        })
+    }
+}
+
+/// An IPv6 address.
+///
+/// This is equivalent to C's `in6_addr`.
+#[repr(transparent)]
+pub struct Ipv6Addr(bindings::in6_addr);
+
+impl Ipv6Addr {
+    /// A wildcard IPv6 address.
+    ///
+    /// Binding to this address means binding to all IPv6 addresses.
+    pub const ANY: Self = Self::new(0, 0, 0, 0, 0, 0, 0, 0);
+
+    /// The IPv6 loopback address.
+    pub const LOOPBACK: Self = Self::new(0, 0, 0, 0, 0, 0, 0, 1);
+
+    /// Creates a new IPv6 address with the given components.
+    #[allow(clippy::too_many_arguments)]
+    pub const fn new(a: u16, b: u16, c: u16, d: u16, e: u16, f: u16, g: u16, h: u16) -> Self {
+        Self(bindings::in6_addr {
+            in6_u: bindings::in6_addr__bindgen_ty_1 {
+                u6_addr16: [
+                    a.to_be(),
+                    b.to_be(),
+                    c.to_be(),
+                    d.to_be(),
+                    e.to_be(),
+                    f.to_be(),
+                    g.to_be(),
+                    h.to_be(),
+                ],
+            },
+        })
+    }
+}
+
+/// A socket address.
+///
+/// It's an enum with either an IPv4 or IPv6 socket address.
+pub enum SocketAddr {
+    /// An IPv4 socket address.
+    V4(SocketAddrV4),
+
+    /// An IPv6 socket address.
+    V6(SocketAddrV6),
+}
+
+/// An IPv4 socket address.
+///
+/// This is equivalent to C's `sockaddr_in`.
+#[repr(transparent)]
+pub struct SocketAddrV4(bindings::sockaddr_in);
+
+impl SocketAddrV4 {
+    /// Creates a new IPv4 socket address.
+    pub const fn new(addr: Ipv4Addr, port: u16) -> Self {
+        Self(bindings::sockaddr_in {
+            sin_family: bindings::AF_INET as _,
+            sin_port: port.to_be(),
+            sin_addr: addr.0,
+            __pad: [0; 8],
+        })
+    }
+}
+
+/// An IPv6 socket address.
+///
+/// This is equivalent to C's `sockaddr_in6`.
+#[repr(transparent)]
+pub struct SocketAddrV6(bindings::sockaddr_in6);
+
+impl SocketAddrV6 {
+    /// Creates a new IPv6 socket address.
+    pub const fn new(addr: Ipv6Addr, port: u16, flowinfo: u32, scopeid: u32) -> Self {
+        Self(bindings::sockaddr_in6 {
+            sin6_family: bindings::AF_INET6 as _,
+            sin6_port: port.to_be(),
+            sin6_addr: addr.0,
+            sin6_flowinfo: flowinfo,
+            sin6_scope_id: scopeid,
+        })
+    }
+}
+
+/// A socket listening on a TCP port.
+///
+/// # Invariants
+///
+/// The socket pointer is always non-null and valid.
+pub struct TcpListener {
+    pub(crate) sock: *mut bindings::socket,
+}
+
+// SAFETY: `TcpListener` is just a wrapper for a kernel socket, which can be used from any thread.
+unsafe impl Send for TcpListener {}
+
+// SAFETY: `TcpListener` is just a wrapper for a kernel socket, which can be used from any thread.
+unsafe impl Sync for TcpListener {}
+
+impl TcpListener {
+    /// Creates a new TCP listener.
+    ///
+    /// It is configured to listen on the given socket address for the given namespace.
+    pub fn try_new(ns: &Namespace, addr: &SocketAddr) -> Result<Self> {
+        let mut socket = core::ptr::null_mut();
+        let (pf, addr, addrlen) = match addr {
+            SocketAddr::V4(addr) => (
+                bindings::PF_INET,
+                addr as *const _ as _,
+                core::mem::size_of::<bindings::sockaddr_in>(),
+            ),
+            SocketAddr::V6(addr) => (
+                bindings::PF_INET6,
+                addr as *const _ as _,
+                core::mem::size_of::<bindings::sockaddr_in6>(),
+            ),
+        };
+
+        // SAFETY: The namespace is valid and the output socket pointer is valid for write.
+        to_result(unsafe {
+            bindings::sock_create_kern(
+                ns.0.get(),
+                pf as _,
+                bindings::sock_type_SOCK_STREAM as _,
+                bindings::IPPROTO_TCP as _,
+                &mut socket,
+            )
+        })?;
+
+        // INVARIANT: The socket was just created, so it is valid.
+        let listener = Self { sock: socket };
+
+        // SAFETY: The type invariant guarantees that the socket is valid, and `addr` and `addrlen`
+        // were initialised based on valid values provided in the address enum.
+        to_result(unsafe { bindings::kernel_bind(socket, addr, addrlen as _) })?;
+
+        // SAFETY: The socket is valid per the type invariant.
+        to_result(unsafe { bindings::kernel_listen(socket, bindings::SOMAXCONN as _) })?;
+
+        Ok(listener)
+    }
+
+    /// Accepts a new connection.
+    ///
+    /// On success, returns the newly-accepted socket stream.
+    ///
+    /// If no connection is available to be accepted, one of two behaviours will occur:
+    /// - If `block` is `false`, returns [`crate::error::code::EAGAIN`];
+    /// - If `block` is `true`, blocks until an error occurs or some connection can be accepted.
+    pub fn accept(&self, block: bool) -> Result<TcpStream> {
+        let mut new = core::ptr::null_mut();
+        let flags = if block { 0 } else { bindings::O_NONBLOCK };
+        // SAFETY: The type invariant guarantees that the socket is valid, and the output argument
+        // is also valid for write.
+        to_result(unsafe { bindings::kernel_accept(self.sock, &mut new, flags as _) })?;
+        Ok(TcpStream { sock: new })
+    }
+}
+
+impl Drop for TcpListener {
+    fn drop(&mut self) {
+        // SAFETY: The type invariant guarantees that the socket is valid.
+        unsafe { bindings::sock_release(self.sock) };
+    }
+}
+
+/// A connected TCP socket.
+///
+/// # Invariants
+///
+/// The socket pointer is always non-null and valid.
+pub struct TcpStream {
+    pub(crate) sock: *mut bindings::socket,
+}
+
+// SAFETY: `TcpStream` is just a wrapper for a kernel socket, which can be used from any thread.
+unsafe impl Send for TcpStream {}
+
+// SAFETY: `TcpStream` is just a wrapper for a kernel socket, which can be used from any thread.
+unsafe impl Sync for TcpStream {}
+
+impl TcpStream {
+    /// Reads data from a connected socket.
+    ///
+    /// On success, returns the number of bytes read, which will be zero if the connection is
+    /// closed.
+    ///
+    /// If no data is immediately available for reading, one of two behaviours will occur:
+    /// - If `block` is `false`, returns [`crate::error::code::EAGAIN`];
+    /// - If `block` is `true`, blocks until an error occurs, the connection is closed, or some
+    ///   becomes readable.
+    pub fn read(&self, buf: &mut [u8], block: bool) -> Result<usize> {
+        let mut msg = bindings::msghdr::default();
+        let mut vec = bindings::kvec {
+            iov_base: buf.as_mut_ptr().cast(),
+            iov_len: buf.len(),
+        };
+        // SAFETY: The type invariant guarantees that the socket is valid, and `vec` was
+        // initialised with the output buffer.
+        let r = unsafe {
+            bindings::kernel_recvmsg(
+                self.sock,
+                &mut msg,
+                &mut vec,
+                1,
+                vec.iov_len,
+                if block { 0 } else { bindings::MSG_DONTWAIT } as _,
+            )
+        };
+        if r < 0 {
+            Err(Error::from_kernel_errno(r))
+        } else {
+            Ok(r as _)
+        }
+    }
+
+    /// Writes data to the connected socket.
+    ///
+    /// On success, returns the number of bytes written.
+    ///
+    /// If the send buffer of the socket is full, one of two behaviours will occur:
+    /// - If `block` is `false`, returns [`crate::error::code::EAGAIN`];
+    /// - If `block` is `true`, blocks until an error occurs or some data is written.
+    pub fn write(&self, buf: &[u8], block: bool) -> Result<usize> {
+        let mut msg = bindings::msghdr {
+            msg_flags: if block { 0 } else { bindings::MSG_DONTWAIT },
+            ..bindings::msghdr::default()
+        };
+        let mut vec = bindings::kvec {
+            iov_base: buf.as_ptr() as *mut u8 as _,
+            iov_len: buf.len(),
+        };
+        // SAFETY: The type invariant guarantees that the socket is valid, and `vec` was
+        // initialised with the input  buffer.
+        let r = unsafe { bindings::kernel_sendmsg(self.sock, &mut msg, &mut vec, 1, vec.iov_len) };
+        if r < 0 {
+            Err(Error::from_kernel_errno(r))
+        } else {
+            Ok(r as _)
+        }
+    }
+}
+
+impl Drop for TcpStream {
+    fn drop(&mut self) {
+        // SAFETY: The type invariant guarantees that the socket is valid.
+        unsafe { bindings::sock_release(self.sock) };
+    }
+}
diff --git a/rust/kernel/net/filter.rs b/rust/kernel/net/filter.rs
new file mode 100644
index 000000000000..a50422d53848
--- /dev/null
+++ b/rust/kernel/net/filter.rs
@@ -0,0 +1,447 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Networking filters.
+//!
+//! C header: [`include/linux/netfilter.h`](../../../../../include/linux/netfilter.h)
+
+use crate::{
+    bindings,
+    error::{code::*, to_result},
+    net,
+    types::PointerWrapper,
+    ARef, AlwaysRefCounted, Result, ScopeGuard,
+};
+use alloc::boxed::Box;
+use core::{
+    marker::{PhantomData, PhantomPinned},
+    pin::Pin,
+};
+
+/// A network filter.
+pub trait Filter {
+    /// The type of the context data stored on registration and made available to the
+    /// [`Filter::filter`] function.
+    type Data: PointerWrapper + Sync = ();
+
+    /// Filters the packet stored in the given buffer.
+    ///
+    /// It dictates to the netfilter core what the fate of the packet should be.
+    fn filter(
+        _data: <Self::Data as PointerWrapper>::Borrowed<'_>,
+        _skb: &net::SkBuff,
+    ) -> Disposition;
+}
+
+/// Specifies the action to be taken by the netfilter core.
+pub enum Disposition {
+    /// Drop the packet.
+    Drop,
+
+    /// Accept the packet.
+    Accept,
+
+    /// The packet was stolen by the filter and must be treated as if it didn't exist.
+    Stolen,
+
+    /// Queue the packet to the given user-space queue.
+    Queue {
+        /// The identifier of the queue to which the packet should be added.
+        queue_id: u16,
+
+        /// Specifies the behaviour if a queue with the given identifier doesn't exist: if `true`,
+        /// the packet is accepted, otherwise it is rejected.
+        accept_if_queue_non_existent: bool,
+    },
+}
+
+/// The filter hook families.
+pub enum Family {
+    ///  IPv4 and IPv6 packets.
+    INet(inet::Hook),
+
+    /// IPv4 packets.
+    Ipv4(ipv4::Hook, ipv4::PriorityBase),
+
+    /// All packets through a device.
+    ///
+    /// When this family is used, a device _must_ be specified.
+    NetDev(netdev::Hook),
+
+    /// IPv6 packets.
+    Ipv6(ipv6::Hook, ipv6::PriorityBase),
+
+    /// Address resolution protocol (ARP) packets.
+    Arp(arp::Hook),
+}
+
+/// A registration of a networking filter.
+///
+/// # Examples
+///
+/// The following is an example of a function that attaches an inbound filter (that always accepts
+/// all packets after printing their lengths) on the specified device (in the `init` ns).
+///
+/// ```
+/// use kernel::net::{self, filter as netfilter};
+///
+/// struct MyFilter;
+/// impl netfilter::Filter for MyFilter {
+///     fn filter(_data: (), skb: &net::SkBuff) -> netfilter::Disposition {
+///         pr_info!("Packet of length {}\n", skb.len());
+///         netfilter::Disposition::Accept
+///     }
+/// }
+///
+/// fn register(name: &CStr) -> Result<Pin<Box<netfilter::Registration<MyFilter>>>> {
+///     let ns = net::init_ns();
+///     let dev = ns.dev_get_by_name(name).ok_or(ENOENT)?;
+///     netfilter::Registration::new_pinned(
+///         netfilter::Family::NetDev(netfilter::netdev::Hook::Ingress),
+///         0,
+///         ns.into(),
+///         Some(dev),
+///         (),
+///     )
+/// }
+/// ```
+#[derive(Default)]
+pub struct Registration<T: Filter> {
+    hook: bindings::nf_hook_ops,
+    // When `ns` is `Some(_)`, the hook is registered.
+    ns: Option<ARef<net::Namespace>>,
+    dev: Option<ARef<net::Device>>,
+    _p: PhantomData<T>,
+    _pinned: PhantomPinned,
+}
+
+// SAFETY: `Registration` does not expose any of its state across threads.
+unsafe impl<T: Filter> Sync for Registration<T> {}
+
+impl<T: Filter> Registration<T> {
+    /// Creates a new [`Registration`] but does not register it yet.
+    ///
+    /// It is allowed to move.
+    pub fn new() -> Self {
+        Self {
+            hook: bindings::nf_hook_ops::default(),
+            dev: None,
+            ns: None,
+            _p: PhantomData,
+            _pinned: PhantomPinned,
+        }
+    }
+
+    /// Creates a new filter registration and registers it.
+    ///
+    /// Returns a pinned heap-allocated representation of the registration.
+    pub fn new_pinned(
+        family: Family,
+        priority: i32,
+        ns: ARef<net::Namespace>,
+        dev: Option<ARef<net::Device>>,
+        data: T::Data,
+    ) -> Result<Pin<Box<Self>>> {
+        let mut filter = Pin::from(Box::try_new(Self::new())?);
+        filter.as_mut().register(family, priority, ns, dev, data)?;
+        Ok(filter)
+    }
+
+    /// Registers a network filter.
+    ///
+    /// It must be pinned because the C portion of the kernel stores a pointer to it while it is
+    /// registered.
+    ///
+    /// The priority is relative to the family's base priority. For example, if the base priority
+    /// is `100` and `priority` is `-1`, the actual priority will be `99`. If a family doesn't
+    /// explicitly allow a base to be specified, `0` is assumed.
+    pub fn register(
+        self: Pin<&mut Self>,
+        family: Family,
+        priority: i32,
+        ns: ARef<net::Namespace>,
+        dev: Option<ARef<net::Device>>,
+        data: T::Data,
+    ) -> Result {
+        // SAFETY: We must ensure that we never move out of `this`.
+        let this = unsafe { self.get_unchecked_mut() };
+        if this.ns.is_some() {
+            // Already registered.
+            return Err(EINVAL);
+        }
+
+        let data_pointer = data.into_pointer();
+
+        // SAFETY: `data_pointer` comes from the call to `data.into_pointer()` above.
+        let guard = ScopeGuard::new(|| unsafe {
+            T::Data::from_pointer(data_pointer);
+        });
+
+        let mut pri_base = 0i32;
+        match family {
+            Family::INet(hook) => {
+                this.hook.pf = bindings::NFPROTO_INET as _;
+                this.hook.hooknum = hook as _;
+            }
+            Family::Ipv4(hook, pbase) => {
+                this.hook.pf = bindings::NFPROTO_IPV4 as _;
+                this.hook.hooknum = hook as _;
+                pri_base = pbase as _;
+            }
+            Family::Ipv6(hook, pbase) => {
+                this.hook.pf = bindings::NFPROTO_IPV6 as _;
+                this.hook.hooknum = hook as _;
+                pri_base = pbase as _;
+            }
+            Family::NetDev(hook) => {
+                this.hook.pf = bindings::NFPROTO_NETDEV as _;
+                this.hook.hooknum = hook as _;
+            }
+            Family::Arp(hook) => {
+                this.hook.pf = bindings::NFPROTO_ARP as _;
+                this.hook.hooknum = hook as _;
+            }
+        }
+
+        this.hook.priority = pri_base.saturating_add(priority);
+        this.hook.priv_ = data_pointer as _;
+        this.hook.hook = Some(Self::hook_callback);
+        crate::static_assert!(bindings::nf_hook_ops_type_NF_HOOK_OP_UNDEFINED == 0);
+
+        if let Some(ref device) = dev {
+            this.hook.dev = device.0.get();
+        }
+
+        // SAFETY: `ns` has a valid reference to the namespace, and `this.hook` was just
+        // initialised above, so they're both valid.
+        to_result(unsafe { bindings::nf_register_net_hook(ns.0.get(), &this.hook) })?;
+
+        this.dev = dev;
+        this.ns = Some(ns);
+        guard.dismiss();
+        Ok(())
+    }
+
+    unsafe extern "C" fn hook_callback(
+        priv_: *mut core::ffi::c_void,
+        skb: *mut bindings::sk_buff,
+        _state: *const bindings::nf_hook_state,
+    ) -> core::ffi::c_uint {
+        // SAFETY: `priv_` was initialised on registration by a value returned from
+        // `T::Data::into_pointer`, and it remains valid until the hook is unregistered.
+        let data = unsafe { T::Data::borrow(priv_) };
+
+        // SAFETY: The C contract guarantees that `skb` remains valid for the duration of this
+        // function call.
+        match T::filter(data, unsafe { net::SkBuff::from_ptr(skb) }) {
+            Disposition::Drop => bindings::NF_DROP,
+            Disposition::Accept => bindings::NF_ACCEPT,
+            Disposition::Stolen => {
+                // SAFETY: This function takes over ownership of `skb` when it returns `NF_STOLEN`,
+                // so we decrement the refcount here to avoid a leak.
+                unsafe { net::SkBuff::dec_ref(core::ptr::NonNull::new(skb).unwrap().cast()) };
+                bindings::NF_STOLEN
+            }
+            Disposition::Queue {
+                queue_id,
+                accept_if_queue_non_existent,
+            } => {
+                // SAFETY: Just an FFI call, no additional safety requirements.
+                let verdict = unsafe { bindings::NF_QUEUE_NR(queue_id as _) };
+                if accept_if_queue_non_existent {
+                    verdict | bindings::NF_VERDICT_FLAG_QUEUE_BYPASS
+                } else {
+                    verdict
+                }
+            }
+        }
+    }
+}
+
+impl<T: Filter> Drop for Registration<T> {
+    fn drop(&mut self) {
+        if let Some(ref ns) = self.ns {
+            // SAFETY: `self.ns` is `Some(_)` only when a previous call to `nf_register_net_hook`
+            // succeeded. And the arguments are the same.
+            unsafe { bindings::nf_unregister_net_hook(ns.0.get(), &self.hook) };
+
+            // `self.hook.priv_` was initialised during registration to a value returned from
+            // `T::Data::into_pointer`, so it is ok to convert back here.
+            unsafe { T::Data::from_pointer(self.hook.priv_) };
+        }
+    }
+}
+
+/// Definitions used when defining hooks for the [`Family::NetDev`] family.
+pub mod netdev {
+    use crate::bindings;
+
+    /// Hooks allowed in the [`super::Family::NetDev`] family.
+    #[repr(u32)]
+    pub enum Hook {
+        /// All inbound packets through the given device.
+        Ingress = bindings::nf_dev_hooks_NF_NETDEV_INGRESS,
+
+        /// All outbound packets through the given device.
+        Egress = bindings::nf_dev_hooks_NF_NETDEV_EGRESS,
+    }
+}
+
+/// Definitions used when defining hooks for the [`Family::Ipv4`] family.
+pub mod ipv4 {
+    use crate::bindings;
+
+    /// Hooks allowed in [`super::Family::Ipv4`] family.
+    pub type Hook = super::inet::Hook;
+
+    /// The base priority for [`super::Family::Ipv4`] hooks.
+    ///
+    /// The actual priority is the base priority plus the priority specified when registering.
+    #[repr(i32)]
+    pub enum PriorityBase {
+        /// Same as the `NF_IP_PRI_FIRST` C constant.
+        First = bindings::nf_ip_hook_priorities_NF_IP_PRI_FIRST,
+
+        /// Same as the `NF_IP_PRI_RAW_BEFORE_DEFRAG` C constant.
+        RawBeforeDefrag = bindings::nf_ip_hook_priorities_NF_IP_PRI_RAW_BEFORE_DEFRAG,
+
+        /// Same as the `NF_IP_PRI_CONNTRACK_DEFRAG` C constant.
+        ConnTrackDefrag = bindings::nf_ip_hook_priorities_NF_IP_PRI_CONNTRACK_DEFRAG,
+
+        /// Same as the `NF_IP_PRI_RAW` C constant.
+        Raw = bindings::nf_ip_hook_priorities_NF_IP_PRI_RAW,
+
+        /// Same as the `NF_IP_PRI_SELINUX_FIRST` C constant.
+        SeLinuxFirst = bindings::nf_ip_hook_priorities_NF_IP_PRI_SELINUX_FIRST,
+
+        /// Same as the `NF_IP_PRI_CONNTRACK` C constant.
+        ConnTrack = bindings::nf_ip_hook_priorities_NF_IP_PRI_CONNTRACK,
+
+        /// Same as the `NF_IP_PRI_MANGLE` C constant.
+        Mangle = bindings::nf_ip_hook_priorities_NF_IP_PRI_MANGLE,
+
+        /// Same as the `NF_IP_PRI_NAT_DST` C constant.
+        NatDst = bindings::nf_ip_hook_priorities_NF_IP_PRI_NAT_DST,
+
+        /// Same as the `NF_IP_PRI_FILTER` C constant.
+        Filter = bindings::nf_ip_hook_priorities_NF_IP_PRI_FILTER,
+
+        /// Same as the `NF_IP_PRI_SECURITY` C constant.
+        Security = bindings::nf_ip_hook_priorities_NF_IP_PRI_SECURITY,
+
+        /// Same as the `NF_IP_PRI_NAT_SRC` C constant.
+        NatSrc = bindings::nf_ip_hook_priorities_NF_IP_PRI_NAT_SRC,
+
+        /// Same as the `NF_IP_PRI_SELINUX_LAST` C constant.
+        SeLinuxLast = bindings::nf_ip_hook_priorities_NF_IP_PRI_SELINUX_LAST,
+
+        /// Same as the `NF_IP_PRI_CONNTRACK_HELPER` C constant.
+        ConnTrackHelper = bindings::nf_ip_hook_priorities_NF_IP_PRI_CONNTRACK_HELPER,
+
+        /// Same as the `NF_IP_PRI_LAST` and `NF_IP_PRI_CONNTRACK_CONFIRM` C constants.
+        Last = bindings::nf_ip_hook_priorities_NF_IP_PRI_LAST,
+    }
+}
+
+/// Definitions used when defining hooks for the [`Family::Ipv6`] family.
+pub mod ipv6 {
+    use crate::bindings;
+
+    /// Hooks allowed in [`super::Family::Ipv6`] family.
+    pub type Hook = super::inet::Hook;
+
+    /// The base priority for [`super::Family::Ipv6`] hooks.
+    ///
+    /// The actual priority is the base priority plus the priority specified when registering.
+    #[repr(i32)]
+    pub enum PriorityBase {
+        /// Same as the `NF_IP6_PRI_FIRST` C constant.
+        First = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_FIRST,
+
+        /// Same as the `NF_IP6_PRI_RAW_BEFORE_DEFRAG` C constant.
+        RawBeforeDefrag = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_RAW_BEFORE_DEFRAG,
+
+        /// Same as the `NF_IP6_PRI_CONNTRACK_DEFRAG` C constant.
+        ConnTrackDefrag = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_CONNTRACK_DEFRAG,
+
+        /// Same as the `NF_IP6_PRI_RAW` C constant.
+        Raw = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_RAW,
+
+        /// Same as the `NF_IP6_PRI_SELINUX_FIRST` C constant.
+        SeLinuxFirst = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_SELINUX_FIRST,
+
+        /// Same as the `NF_IP6_PRI_CONNTRACK` C constant.
+        ConnTrack = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_CONNTRACK,
+
+        /// Same as the `NF_IP6_PRI_MANGLE` C constant.
+        Mangle = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_MANGLE,
+
+        /// Same as the `NF_IP6_PRI_NAT_DST` C constant.
+        NatDst = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_NAT_DST,
+
+        /// Same as the `NF_IP6_PRI_FILTER` C constant.
+        Filter = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_FILTER,
+
+        /// Same as the `NF_IP6_PRI_SECURITY` C constant.
+        Security = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_SECURITY,
+
+        /// Same as the `NF_IP6_PRI_NAT_SRC` C constant.
+        NatSrc = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_NAT_SRC,
+
+        /// Same as the `NF_IP6_PRI_SELINUX_LAST` C constant.
+        SeLinuxLast = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_SELINUX_LAST,
+
+        /// Same as the `NF_IP6_PRI_CONNTRACK_HELPER` C constant.
+        ConnTrackHelper = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_CONNTRACK_HELPER,
+
+        /// Same as the `NF_IP6_PRI_LAST` C constant.
+        Last = bindings::nf_ip6_hook_priorities_NF_IP6_PRI_LAST,
+    }
+}
+
+/// Definitions used when defining hooks for the [`Family::Arp`] family.
+pub mod arp {
+    use crate::bindings;
+
+    /// Hooks allowed in the [`super::Family::Arp`] family.
+    #[repr(u32)]
+    pub enum Hook {
+        /// Inbound ARP packets.
+        In = bindings::NF_ARP_IN,
+
+        /// Outbound ARP packets.
+        Out = bindings::NF_ARP_OUT,
+
+        /// Forwarded ARP packets.
+        Forward = bindings::NF_ARP_FORWARD,
+    }
+}
+
+/// Definitions used when defining hooks for the [`Family::INet`] family.
+pub mod inet {
+    use crate::bindings;
+
+    /// Hooks allowed in the [`super::Family::INet`], [`super::Family::Ipv4`], and
+    /// [`super::Family::Ipv6`] families.
+    #[repr(u32)]
+    pub enum Hook {
+        /// Inbound packets before routing decisions are made (i.e., before it's determined if the
+        /// packet is to be delivered locally or forwarded to another host).
+        PreRouting = bindings::nf_inet_hooks_NF_INET_PRE_ROUTING as _,
+
+        /// Inbound packets that are meant to be delivered locally.
+        LocalIn = bindings::nf_inet_hooks_NF_INET_LOCAL_IN as _,
+
+        /// Inbound packets that are meant to be forwarded to another host.
+        Forward = bindings::nf_inet_hooks_NF_INET_FORWARD as _,
+
+        /// Outbound packet created by the local networking stack.
+        LocalOut = bindings::nf_inet_hooks_NF_INET_LOCAL_OUT as _,
+
+        /// All outbound packets (i.e., generated locally or being forwarded to another host).
+        PostRouting = bindings::nf_inet_hooks_NF_INET_POST_ROUTING as _,
+
+        /// Equivalent to [`super::netdev::Hook::Ingress`], so a device must be specified. Packets
+        /// of all types (not just ipv4/ipv6) will be delivered to the filter.
+        Ingress = bindings::nf_inet_hooks_NF_INET_INGRESS as _,
+    }
+}
diff --git a/rust/kernel/of.rs b/rust/kernel/of.rs
new file mode 100644
index 000000000000..cdcd83244337
--- /dev/null
+++ b/rust/kernel/of.rs
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Devicetree and Open Firmware abstractions.
+//!
+//! C header: [`include/linux/of_*.h`](../../../../include/linux/of_*.h)
+
+use crate::{bindings, driver, str::BStr};
+
+/// An open firmware device id.
+#[derive(Clone, Copy)]
+pub enum DeviceId {
+    /// An open firmware device id where only a compatible string is specified.
+    Compatible(&'static BStr),
+}
+
+/// Defines a const open firmware device id table that also carries per-entry data/context/info.
+///
+/// The name of the const is `OF_DEVICE_ID_TABLE`, which is what buses are expected to name their
+/// open firmware tables.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::define_of_id_table;
+/// use kernel::of;
+///
+/// define_of_id_table! {u32, [
+///     (of::DeviceId::Compatible(b"test-device1,test-device2"), Some(0xff)),
+///     (of::DeviceId::Compatible(b"test-device3"), None),
+/// ]};
+/// ```
+#[macro_export]
+macro_rules! define_of_id_table {
+    ($data_type:ty, $($t:tt)*) => {
+        $crate::define_id_table!(OF_DEVICE_ID_TABLE, $crate::of::DeviceId, $data_type, $($t)*);
+    };
+}
+
+// SAFETY: `ZERO` is all zeroed-out and `to_rawid` stores `offset` in `of_device_id::data`.
+unsafe impl const driver::RawDeviceId for DeviceId {
+    type RawType = bindings::of_device_id;
+    const ZERO: Self::RawType = bindings::of_device_id {
+        name: [0; 32],
+        type_: [0; 32],
+        compatible: [0; 128],
+        data: core::ptr::null(),
+    };
+
+    fn to_rawid(&self, offset: isize) -> Self::RawType {
+        let DeviceId::Compatible(compatible) = self;
+        let mut id = Self::ZERO;
+        let mut i = 0;
+        while i < compatible.len() {
+            // If `compatible` does not fit in `id.compatible`, an "index out of bounds" build time
+            // error will be triggered.
+            id.compatible[i] = compatible[i] as _;
+            i += 1;
+        }
+        id.compatible[i] = b'\0' as _;
+        id.data = offset as _;
+        id
+    }
+}
diff --git a/rust/kernel/pages.rs b/rust/kernel/pages.rs
new file mode 100644
index 000000000000..f2bb26810cd7
--- /dev/null
+++ b/rust/kernel/pages.rs
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel page allocation and management.
+//!
+//! TODO: This module is a work in progress.
+
+use crate::{
+    bindings, error::code::*, io_buffer::IoBufferReader, user_ptr::UserSlicePtrReader, Result,
+    PAGE_SIZE,
+};
+use core::{marker::PhantomData, ptr};
+
+/// A set of physical pages.
+///
+/// `Pages` holds a reference to a set of pages of order `ORDER`. Having the order as a generic
+/// const allows the struct to have the same size as a pointer.
+///
+/// # Invariants
+///
+/// The pointer `Pages::pages` is valid and points to 2^ORDER pages.
+pub struct Pages<const ORDER: u32> {
+    pub(crate) pages: *mut bindings::page,
+}
+
+impl<const ORDER: u32> Pages<ORDER> {
+    /// Allocates a new set of contiguous pages.
+    pub fn new() -> Result<Self> {
+        // TODO: Consider whether we want to allow callers to specify flags.
+        // SAFETY: This only allocates pages. We check that it succeeds in the next statement.
+        let pages = unsafe {
+            bindings::alloc_pages(
+                bindings::GFP_KERNEL | bindings::__GFP_ZERO | bindings::__GFP_HIGHMEM,
+                ORDER,
+            )
+        };
+        if pages.is_null() {
+            return Err(ENOMEM);
+        }
+        // INVARIANTS: We checked that the allocation above succeeded.
+        Ok(Self { pages })
+    }
+
+    /// Copies data from the given [`UserSlicePtrReader`] into the pages.
+    pub fn copy_into_page(
+        &self,
+        reader: &mut UserSlicePtrReader,
+        offset: usize,
+        len: usize,
+    ) -> Result {
+        // TODO: For now this only works on the first page.
+        let end = offset.checked_add(len).ok_or(EINVAL)?;
+        if end > PAGE_SIZE {
+            return Err(EINVAL);
+        }
+
+        let mapping = self.kmap(0).ok_or(EINVAL)?;
+
+        // SAFETY: We ensured that the buffer was valid with the check above.
+        unsafe { reader.read_raw((mapping.ptr as usize + offset) as _, len) }?;
+        Ok(())
+    }
+
+    /// Maps the pages and reads from them into the given buffer.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that the destination buffer is valid for the given length.
+    /// Additionally, if the raw buffer is intended to be recast, they must ensure that the data
+    /// can be safely cast; [`crate::io_buffer::ReadableFromBytes`] has more details about it.
+    pub unsafe fn read(&self, dest: *mut u8, offset: usize, len: usize) -> Result {
+        // TODO: For now this only works on the first page.
+        let end = offset.checked_add(len).ok_or(EINVAL)?;
+        if end > PAGE_SIZE {
+            return Err(EINVAL);
+        }
+
+        let mapping = self.kmap(0).ok_or(EINVAL)?;
+        unsafe { ptr::copy((mapping.ptr as *mut u8).add(offset), dest, len) };
+        Ok(())
+    }
+
+    /// Maps the pages and writes into them from the given buffer.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that the buffer is valid for the given length. Additionally, if the
+    /// page is (or will be) mapped by userspace, they must ensure that no kernel data is leaked
+    /// through padding if it was cast from another type; [`crate::io_buffer::WritableToBytes`] has
+    /// more details about it.
+    pub unsafe fn write(&self, src: *const u8, offset: usize, len: usize) -> Result {
+        // TODO: For now this only works on the first page.
+        let end = offset.checked_add(len).ok_or(EINVAL)?;
+        if end > PAGE_SIZE {
+            return Err(EINVAL);
+        }
+
+        let mapping = self.kmap(0).ok_or(EINVAL)?;
+        unsafe { ptr::copy(src, (mapping.ptr as *mut u8).add(offset), len) };
+        Ok(())
+    }
+
+    /// Maps the page at index `index`.
+    fn kmap(&self, index: usize) -> Option<PageMapping<'_>> {
+        if index >= 1usize << ORDER {
+            return None;
+        }
+
+        // SAFETY: We checked above that `index` is within range.
+        let page = unsafe { self.pages.add(index) };
+
+        // SAFETY: `page` is valid based on the checks above.
+        let ptr = unsafe { bindings::kmap(page) };
+        if ptr.is_null() {
+            return None;
+        }
+
+        Some(PageMapping {
+            page,
+            ptr,
+            _phantom: PhantomData,
+        })
+    }
+}
+
+impl<const ORDER: u32> Drop for Pages<ORDER> {
+    fn drop(&mut self) {
+        // SAFETY: By the type invariants, we know the pages are allocated with the given order.
+        unsafe { bindings::__free_pages(self.pages, ORDER) };
+    }
+}
+
+struct PageMapping<'a> {
+    page: *mut bindings::page,
+    ptr: *mut core::ffi::c_void,
+    _phantom: PhantomData<&'a i32>,
+}
+
+impl Drop for PageMapping<'_> {
+    fn drop(&mut self) {
+        // SAFETY: An instance of `PageMapping` is created only when `kmap` succeeded for the given
+        // page, so it is safe to unmap it here.
+        unsafe { bindings::kunmap(self.page) };
+    }
+}
diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs
new file mode 100644
index 000000000000..d8cc0e0120aa
--- /dev/null
+++ b/rust/kernel/platform.rs
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Platform devices and drivers.
+//!
+//! Also called `platdev`, `pdev`.
+//!
+//! C header: [`include/linux/platform_device.h`](../../../../include/linux/platform_device.h)
+
+use crate::{
+    bindings,
+    device::{self, RawDevice},
+    driver,
+    error::{from_kernel_result, Result},
+    of,
+    str::CStr,
+    to_result,
+    types::PointerWrapper,
+    ThisModule,
+};
+
+/// A registration of a platform driver.
+pub type Registration<T> = driver::Registration<Adapter<T>>;
+
+/// An adapter for the registration of platform drivers.
+pub struct Adapter<T: Driver>(T);
+
+impl<T: Driver> driver::DriverOps for Adapter<T> {
+    type RegType = bindings::platform_driver;
+
+    unsafe fn register(
+        reg: *mut bindings::platform_driver,
+        name: &'static CStr,
+        module: &'static ThisModule,
+    ) -> Result {
+        // SAFETY: By the safety requirements of this function (defined in the trait definition),
+        // `reg` is non-null and valid.
+        let pdrv = unsafe { &mut *reg };
+
+        pdrv.driver.name = name.as_char_ptr();
+        pdrv.probe = Some(Self::probe_callback);
+        pdrv.remove = Some(Self::remove_callback);
+        if let Some(t) = T::OF_DEVICE_ID_TABLE {
+            pdrv.driver.of_match_table = t.as_ref();
+        }
+        // SAFETY:
+        //   - `pdrv` lives at least until the call to `platform_driver_unregister()` returns.
+        //   - `name` pointer has static lifetime.
+        //   - `module.0` lives at least as long as the module.
+        //   - `probe()` and `remove()` are static functions.
+        //   - `of_match_table` is either a raw pointer with static lifetime,
+        //      as guaranteed by the [`driver::IdTable`] type, or null.
+        to_result(unsafe { bindings::__platform_driver_register(reg, module.0) })
+    }
+
+    unsafe fn unregister(reg: *mut bindings::platform_driver) {
+        // SAFETY: By the safety requirements of this function (defined in the trait definition),
+        // `reg` was passed (and updated) by a previous successful call to
+        // `platform_driver_register`.
+        unsafe { bindings::platform_driver_unregister(reg) };
+    }
+}
+
+impl<T: Driver> Adapter<T> {
+    fn get_id_info(dev: &Device) -> Option<&'static T::IdInfo> {
+        let table = T::OF_DEVICE_ID_TABLE?;
+
+        // SAFETY: `table` has static lifetime, so it is valid for read. `dev` is guaranteed to be
+        // valid while it's alive, so is the raw device returned by it.
+        let id = unsafe { bindings::of_match_device(table.as_ref(), dev.raw_device()) };
+        if id.is_null() {
+            return None;
+        }
+
+        // SAFETY: `id` is a pointer within the static table, so it's always valid.
+        let offset = unsafe { (*id).data };
+        if offset.is_null() {
+            return None;
+        }
+
+        // SAFETY: The offset comes from a previous call to `offset_from` in `IdArray::new`, which
+        // guarantees that the resulting pointer is within the table.
+        let ptr = unsafe {
+            id.cast::<u8>()
+                .offset(offset as _)
+                .cast::<Option<T::IdInfo>>()
+        };
+
+        // SAFETY: The id table has a static lifetime, so `ptr` is guaranteed to be valid for read.
+        unsafe { (&*ptr).as_ref() }
+    }
+
+    extern "C" fn probe_callback(pdev: *mut bindings::platform_device) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: `pdev` is valid by the contract with the C code. `dev` is alive only for the
+            // duration of this call, so it is guaranteed to remain alive for the lifetime of
+            // `pdev`.
+            let mut dev = unsafe { Device::from_ptr(pdev) };
+            let info = Self::get_id_info(&dev);
+            let data = T::probe(&mut dev, info)?;
+            // SAFETY: `pdev` is guaranteed to be a valid, non-null pointer.
+            unsafe { bindings::platform_set_drvdata(pdev, data.into_pointer() as _) };
+            Ok(0)
+        }
+    }
+
+    extern "C" fn remove_callback(pdev: *mut bindings::platform_device) -> core::ffi::c_int {
+        from_kernel_result! {
+            // SAFETY: `pdev` is guaranteed to be a valid, non-null pointer.
+            let ptr = unsafe { bindings::platform_get_drvdata(pdev) };
+            // SAFETY:
+            //   - we allocated this pointer using `T::Data::into_pointer`,
+            //     so it is safe to turn back into a `T::Data`.
+            //   - the allocation happened in `probe`, no-one freed the memory,
+            //     `remove` is the canonical kernel location to free driver data. so OK
+            //     to convert the pointer back to a Rust structure here.
+            let data = unsafe { T::Data::from_pointer(ptr) };
+            let ret = T::remove(&data);
+            <T::Data as driver::DeviceRemoval>::device_remove(&data);
+            ret?;
+            Ok(0)
+        }
+    }
+}
+
+/// A platform driver.
+pub trait Driver {
+    /// Data stored on device by driver.
+    ///
+    /// Corresponds to the data set or retrieved via the kernel's
+    /// `platform_{set,get}_drvdata()` functions.
+    ///
+    /// Require that `Data` implements `PointerWrapper`. We guarantee to
+    /// never move the underlying wrapped data structure. This allows
+    type Data: PointerWrapper + Send + Sync + driver::DeviceRemoval = ();
+
+    /// The type holding information about each device id supported by the driver.
+    type IdInfo: 'static = ();
+
+    /// The table of device ids supported by the driver.
+    const OF_DEVICE_ID_TABLE: Option<driver::IdTable<'static, of::DeviceId, Self::IdInfo>> = None;
+
+    /// Platform driver probe.
+    ///
+    /// Called when a new platform device is added or discovered.
+    /// Implementers should attempt to initialize the device here.
+    fn probe(dev: &mut Device, id_info: Option<&Self::IdInfo>) -> Result<Self::Data>;
+
+    /// Platform driver remove.
+    ///
+    /// Called when a platform device is removed.
+    /// Implementers should prepare the device for complete removal here.
+    fn remove(_data: &Self::Data) -> Result {
+        Ok(())
+    }
+}
+
+/// A platform device.
+///
+/// # Invariants
+///
+/// The field `ptr` is non-null and valid for the lifetime of the object.
+pub struct Device {
+    ptr: *mut bindings::platform_device,
+}
+
+impl Device {
+    /// Creates a new device from the given pointer.
+    ///
+    /// # Safety
+    ///
+    /// `ptr` must be non-null and valid. It must remain valid for the lifetime of the returned
+    /// instance.
+    unsafe fn from_ptr(ptr: *mut bindings::platform_device) -> Self {
+        // INVARIANT: The safety requirements of the function ensure the lifetime invariant.
+        Self { ptr }
+    }
+
+    /// Returns id of the platform device.
+    pub fn id(&self) -> i32 {
+        // SAFETY: By the type invariants, we know that `self.ptr` is non-null and valid.
+        unsafe { (*self.ptr).id }
+    }
+}
+
+// SAFETY: The device returned by `raw_device` is the raw platform device.
+unsafe impl device::RawDevice for Device {
+    fn raw_device(&self) -> *mut bindings::device {
+        // SAFETY: By the type invariants, we know that `self.ptr` is non-null and valid.
+        unsafe { &mut (*self.ptr).dev }
+    }
+}
+
+/// Declares a kernel module that exposes a single platform driver.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::{platform, define_of_id_table, module_platform_driver};
+/// #
+/// struct MyDriver;
+/// impl platform::Driver for MyDriver {
+///     // [...]
+/// #   fn probe(_dev: &mut platform::Device, _id_info: Option<&Self::IdInfo>) -> Result {
+/// #       Ok(())
+/// #   }
+/// #   define_of_id_table! {(), [
+/// #       (of::DeviceId::Compatible(b"brcm,bcm2835-rng"), None),
+/// #   ]}
+/// }
+///
+/// module_platform_driver! {
+///     type: MyDriver,
+///     name: b"module_name",
+///     author: b"Author name",
+///     license: b"GPL",
+/// }
+/// ```
+#[macro_export]
+macro_rules! module_platform_driver {
+    ($($f:tt)*) => {
+        $crate::module_driver!(<T>, $crate::platform::Adapter<T>, { $($f)* });
+    };
+}
diff --git a/rust/kernel/power.rs b/rust/kernel/power.rs
new file mode 100644
index 000000000000..ef788557b269
--- /dev/null
+++ b/rust/kernel/power.rs
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Power management interfaces.
+//!
+//! C header: [`include/linux/pm.h`](../../../../include/linux/pm.h)
+
+#![allow(dead_code)]
+
+use crate::{bindings, error::from_kernel_result, types::PointerWrapper, Result};
+use core::marker::PhantomData;
+
+/// Corresponds to the kernel's `struct dev_pm_ops`.
+///
+/// It is meant to be implemented by drivers that support power-management operations.
+pub trait Operations {
+    /// The type of the context data stored by the driver on each device.
+    type Data: PointerWrapper + Sync + Send;
+
+    /// Called before the system goes into a sleep state.
+    fn suspend(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+        Ok(())
+    }
+
+    /// Called after the system comes back from a sleep state.
+    fn resume(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+        Ok(())
+    }
+
+    /// Called before creating a hibernation image.
+    fn freeze(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+        Ok(())
+    }
+
+    /// Called after the system is restored from a hibernation image.
+    fn restore(_data: <Self::Data as PointerWrapper>::Borrowed<'_>) -> Result {
+        Ok(())
+    }
+}
+
+macro_rules! pm_callback {
+    ($callback:ident, $method:ident) => {
+        unsafe extern "C" fn $callback<T: Operations>(
+            dev: *mut bindings::device,
+        ) -> core::ffi::c_int {
+            from_kernel_result! {
+                // SAFETY: `dev` is valid as it was passed in by the C portion.
+                let ptr = unsafe { bindings::dev_get_drvdata(dev) };
+                // SAFETY: By the safety requirements of `OpsTable::build`, we know that `ptr` came
+                // from a previous call to `T::Data::into_pointer`.
+                let data = unsafe { T::Data::borrow(ptr) };
+                T::$method(data)?;
+                Ok(0)
+            }
+        }
+    };
+}
+
+pm_callback!(suspend_callback, suspend);
+pm_callback!(resume_callback, resume);
+pm_callback!(freeze_callback, freeze);
+pm_callback!(restore_callback, restore);
+
+pub(crate) struct OpsTable<T: Operations>(PhantomData<*const T>);
+
+impl<T: Operations> OpsTable<T> {
+    const VTABLE: bindings::dev_pm_ops = bindings::dev_pm_ops {
+        prepare: None,
+        complete: None,
+        suspend: Some(suspend_callback::<T>),
+        resume: Some(resume_callback::<T>),
+        freeze: Some(freeze_callback::<T>),
+        thaw: None,
+        poweroff: None,
+        restore: Some(restore_callback::<T>),
+        suspend_late: None,
+        resume_early: None,
+        freeze_late: None,
+        thaw_early: None,
+        poweroff_late: None,
+        restore_early: None,
+        suspend_noirq: None,
+        resume_noirq: None,
+        freeze_noirq: None,
+        thaw_noirq: None,
+        poweroff_noirq: None,
+        restore_noirq: None,
+        runtime_suspend: None,
+        runtime_resume: None,
+        runtime_idle: None,
+    };
+
+    /// Builds an instance of `struct dev_pm_ops`.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `dev_get_drvdata` will result in a value returned by
+    /// [`T::Data::into_pointer`].
+    pub(crate) const unsafe fn build() -> &'static bindings::dev_pm_ops {
+        &Self::VTABLE
+    }
+}
+
+/// Implements the [`Operations`] trait as no-ops.
+///
+/// This is useful when one doesn't want to provide the implementation of any power-manager related
+/// operation.
+pub struct NoOperations<T: PointerWrapper>(PhantomData<T>);
+
+impl<T: PointerWrapper + Send + Sync> Operations for NoOperations<T> {
+    type Data = T;
+}
+
+// SAFETY: `NoOperation` provides no functionality, it is safe to send a reference to it to
+// different threads.
+unsafe impl<T: PointerWrapper> Sync for NoOperations<T> {}
+
+// SAFETY: `NoOperation` provides no functionality, it is safe to send it to different threads.
+unsafe impl<T: PointerWrapper> Send for NoOperations<T> {}
diff --git a/rust/kernel/prelude.rs b/rust/kernel/prelude.rs
new file mode 100644
index 000000000000..26f8af9e16ab
--- /dev/null
+++ b/rust/kernel/prelude.rs
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! The `kernel` prelude.
+//!
+//! These are the most common items used by Rust code in the kernel,
+//! intended to be imported by all Rust code, for convenience.
+//!
+//! # Examples
+//!
+//! ```
+//! use kernel::prelude::*;
+//! ```
+
+pub use core::pin::Pin;
+
+pub use alloc::{boxed::Box, string::String, vec::Vec};
+
+pub use macros::{module, vtable};
+
+pub use super::build_assert;
+
+pub use super::{
+    dbg, dev_alert, dev_crit, dev_dbg, dev_emerg, dev_err, dev_info, dev_notice, dev_warn, fmt,
+    pr_alert, pr_crit, pr_debug, pr_emerg, pr_err, pr_info, pr_notice, pr_warn,
+};
+
+pub use super::{module_fs, module_misc_device};
+
+#[cfg(CONFIG_ARM_AMBA)]
+pub use super::module_amba_driver;
+
+pub use super::static_assert;
+
+pub use super::{error::code::*, Error, Result};
+
+pub use super::{str::CStr, ARef, ThisModule};
diff --git a/rust/kernel/print.rs b/rust/kernel/print.rs
new file mode 100644
index 000000000000..92541efc7e22
--- /dev/null
+++ b/rust/kernel/print.rs
@@ -0,0 +1,406 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Printing facilities.
+//!
+//! C header: [`include/linux/printk.h`](../../../../include/linux/printk.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/core-api/printk-basics.html>
+
+use core::{
+    ffi::{c_char, c_void},
+    fmt,
+};
+
+use crate::str::RawFormatter;
+
+#[cfg(CONFIG_PRINTK)]
+use crate::bindings;
+
+// Called from `vsprintf` with format specifier `%pA`.
+#[no_mangle]
+unsafe fn rust_fmt_argument(buf: *mut c_char, end: *mut c_char, ptr: *const c_void) -> *mut c_char {
+    use fmt::Write;
+    // SAFETY: The C contract guarantees that `buf` is valid if it's less than `end`.
+    let mut w = unsafe { RawFormatter::from_ptrs(buf.cast(), end.cast()) };
+    let _ = w.write_fmt(unsafe { *(ptr as *const fmt::Arguments<'_>) });
+    w.pos().cast()
+}
+
+/// Format strings.
+///
+/// Public but hidden since it should only be used from public macros.
+#[doc(hidden)]
+pub mod format_strings {
+    use crate::bindings;
+
+    /// The length we copy from the `KERN_*` kernel prefixes.
+    const LENGTH_PREFIX: usize = 2;
+
+    /// The length of the fixed format strings.
+    pub const LENGTH: usize = 10;
+
+    /// Generates a fixed format string for the kernel's [`_printk`].
+    ///
+    /// The format string is always the same for a given level, i.e. for a
+    /// given `prefix`, which are the kernel's `KERN_*` constants.
+    ///
+    /// [`_printk`]: ../../../../include/linux/printk.h
+    const fn generate(is_cont: bool, prefix: &[u8; 3]) -> [u8; LENGTH] {
+        // Ensure the `KERN_*` macros are what we expect.
+        assert!(prefix[0] == b'\x01');
+        if is_cont {
+            assert!(prefix[1] == b'c');
+        } else {
+            assert!(prefix[1] >= b'0' && prefix[1] <= b'7');
+        }
+        assert!(prefix[2] == b'\x00');
+
+        let suffix: &[u8; LENGTH - LENGTH_PREFIX] = if is_cont {
+            b"%pA\0\0\0\0\0"
+        } else {
+            b"%s: %pA\0"
+        };
+
+        [
+            prefix[0], prefix[1], suffix[0], suffix[1], suffix[2], suffix[3], suffix[4], suffix[5],
+            suffix[6], suffix[7],
+        ]
+    }
+
+    // Generate the format strings at compile-time.
+    //
+    // This avoids the compiler generating the contents on the fly in the stack.
+    //
+    // Furthermore, `static` instead of `const` is used to share the strings
+    // for all the kernel.
+    pub static EMERG: [u8; LENGTH] = generate(false, bindings::KERN_EMERG);
+    pub static ALERT: [u8; LENGTH] = generate(false, bindings::KERN_ALERT);
+    pub static CRIT: [u8; LENGTH] = generate(false, bindings::KERN_CRIT);
+    pub static ERR: [u8; LENGTH] = generate(false, bindings::KERN_ERR);
+    pub static WARNING: [u8; LENGTH] = generate(false, bindings::KERN_WARNING);
+    pub static NOTICE: [u8; LENGTH] = generate(false, bindings::KERN_NOTICE);
+    pub static INFO: [u8; LENGTH] = generate(false, bindings::KERN_INFO);
+    pub static DEBUG: [u8; LENGTH] = generate(false, bindings::KERN_DEBUG);
+    pub static CONT: [u8; LENGTH] = generate(true, bindings::KERN_CONT);
+}
+
+/// Prints a message via the kernel's [`_printk`].
+///
+/// Public but hidden since it should only be used from public macros.
+///
+/// # Safety
+///
+/// The format string must be one of the ones in [`format_strings`], and
+/// the module name must be null-terminated.
+///
+/// [`_printk`]: ../../../../include/linux/_printk.h
+#[doc(hidden)]
+#[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))]
+pub unsafe fn call_printk(
+    format_string: &[u8; format_strings::LENGTH],
+    module_name: &[u8],
+    args: fmt::Arguments<'_>,
+) {
+    // `_printk` does not seem to fail in any path.
+    #[cfg(CONFIG_PRINTK)]
+    unsafe {
+        bindings::_printk(
+            format_string.as_ptr() as _,
+            module_name.as_ptr(),
+            &args as *const _ as *const c_void,
+        );
+    }
+}
+
+/// Prints a message via the kernel's [`_printk`] for the `CONT` level.
+///
+/// Public but hidden since it should only be used from public macros.
+///
+/// [`_printk`]: ../../../../include/linux/printk.h
+#[doc(hidden)]
+#[cfg_attr(not(CONFIG_PRINTK), allow(unused_variables))]
+pub fn call_printk_cont(args: fmt::Arguments<'_>) {
+    // `_printk` does not seem to fail in any path.
+    //
+    // SAFETY: The format string is fixed.
+    #[cfg(CONFIG_PRINTK)]
+    unsafe {
+        bindings::_printk(
+            format_strings::CONT.as_ptr() as _,
+            &args as *const _ as *const c_void,
+        );
+    }
+}
+
+/// Performs formatting and forwards the string to [`call_printk`].
+///
+/// Public but hidden since it should only be used from public macros.
+#[doc(hidden)]
+#[cfg(not(testlib))]
+#[macro_export]
+#[allow(clippy::crate_in_macro_def)]
+macro_rules! print_macro (
+    // The non-continuation cases (most of them, e.g. `INFO`).
+    ($format_string:path, false, $($arg:tt)+) => (
+        // SAFETY: This hidden macro should only be called by the documented
+        // printing macros which ensure the format string is one of the fixed
+        // ones. All `__LOG_PREFIX`s are null-terminated as they are generated
+        // by the `module!` proc macro or fixed values defined in a kernel
+        // crate.
+        unsafe {
+            $crate::print::call_printk(
+                &$format_string,
+                crate::__LOG_PREFIX,
+                format_args!($($arg)+),
+            );
+        }
+    );
+
+    // The `CONT` case.
+    ($format_string:path, true, $($arg:tt)+) => (
+        $crate::print::call_printk_cont(
+            format_args!($($arg)+),
+        );
+    );
+);
+
+/// Stub for doctests
+#[cfg(testlib)]
+#[macro_export]
+macro_rules! print_macro (
+    ($format_string:path, $e:expr, $($arg:tt)+) => (
+        ()
+    );
+);
+
+// We could use a macro to generate these macros. However, doing so ends
+// up being a bit ugly: it requires the dollar token trick to escape `$` as
+// well as playing with the `doc` attribute. Furthermore, they cannot be easily
+// imported in the prelude due to [1]. So, for the moment, we just write them
+// manually, like in the C side; while keeping most of the logic in another
+// macro, i.e. [`print_macro`].
+//
+// [1]: https://github.com/rust-lang/rust/issues/52234
+
+/// Prints an emergency-level message (level 0).
+///
+/// Use this level if the system is unusable.
+///
+/// Equivalent to the kernel's [`pr_emerg`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_emerg`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_emerg
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_emerg!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_emerg (
+    ($($arg:tt)*) => (
+        $crate::print_macro!($crate::print::format_strings::EMERG, false, $($arg)*)
+    )
+);
+
+/// Prints an alert-level message (level 1).
+///
+/// Use this level if action must be taken immediately.
+///
+/// Equivalent to the kernel's [`pr_alert`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_alert`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_alert
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_alert!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_alert (
+    ($($arg:tt)*) => (
+        $crate::print_macro!($crate::print::format_strings::ALERT, false, $($arg)*)
+    )
+);
+
+/// Prints a critical-level message (level 2).
+///
+/// Use this level for critical conditions.
+///
+/// Equivalent to the kernel's [`pr_crit`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_crit`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_crit
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_crit!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_crit (
+    ($($arg:tt)*) => (
+        $crate::print_macro!($crate::print::format_strings::CRIT, false, $($arg)*)
+    )
+);
+
+/// Prints an error-level message (level 3).
+///
+/// Use this level for error conditions.
+///
+/// Equivalent to the kernel's [`pr_err`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_err`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_err
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_err!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_err (
+    ($($arg:tt)*) => (
+        $crate::print_macro!($crate::print::format_strings::ERR, false, $($arg)*)
+    )
+);
+
+/// Prints a warning-level message (level 4).
+///
+/// Use this level for warning conditions.
+///
+/// Equivalent to the kernel's [`pr_warn`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_warn`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_warn
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_warn!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_warn (
+    ($($arg:tt)*) => (
+        $crate::print_macro!($crate::print::format_strings::WARNING, false, $($arg)*)
+    )
+);
+
+/// Prints a notice-level message (level 5).
+///
+/// Use this level for normal but significant conditions.
+///
+/// Equivalent to the kernel's [`pr_notice`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_notice`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_notice
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_notice!("hello {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_notice (
+    ($($arg:tt)*) => (
+        $crate::print_macro!($crate::print::format_strings::NOTICE, false, $($arg)*)
+    )
+);
+
+/// Prints an info-level message (level 6).
+///
+/// Use this level for informational messages.
+///
+/// Equivalent to the kernel's [`pr_info`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_info`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_info
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_info!("hello {}\n", "there");
+/// ```
+#[macro_export]
+#[doc(alias = "print")]
+macro_rules! pr_info (
+    ($($arg:tt)*) => (
+        $crate::print_macro!($crate::print::format_strings::INFO, false, $($arg)*)
+    )
+);
+
+/// Prints a debug-level message (level 7).
+///
+/// Use this level for debug messages.
+///
+/// Equivalent to the kernel's [`pr_debug`] macro, except that it doesn't support dynamic debug
+/// yet.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_debug`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_debug
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// pr_debug!("hello {}\n", "there");
+/// ```
+#[macro_export]
+#[doc(alias = "print")]
+macro_rules! pr_debug (
+    ($($arg:tt)*) => (
+        if cfg!(debug_assertions) {
+            $crate::print_macro!($crate::print::format_strings::DEBUG, false, $($arg)*)
+        }
+    )
+);
+
+/// Continues a previous log message in the same line.
+///
+/// Use only when continuing a previous `pr_*!` macro (e.g. [`pr_info!`]).
+///
+/// Equivalent to the kernel's [`pr_cont`] macro.
+///
+/// Mimics the interface of [`std::print!`]. See [`core::fmt`] and
+/// [`alloc::format!`] for information about the formatting syntax.
+///
+/// [`pr_cont`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html#c.pr_cont
+/// [`std::print!`]: https://doc.rust-lang.org/std/macro.print.html
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::pr_cont;
+/// pr_info!("hello");
+/// pr_cont!(" {}\n", "there");
+/// ```
+#[macro_export]
+macro_rules! pr_cont (
+    ($($arg:tt)*) => (
+        $crate::print_macro!($crate::print::format_strings::CONT, true, $($arg)*)
+    )
+);
diff --git a/rust/kernel/random.rs b/rust/kernel/random.rs
new file mode 100644
index 000000000000..c30dd675d6a0
--- /dev/null
+++ b/rust/kernel/random.rs
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Random numbers.
+//!
+//! C header: [`include/linux/random.h`](../../../../include/linux/random.h)
+
+use crate::{bindings, error::code::*, Error, Result};
+
+/// Fills a byte slice with random bytes generated from the kernel's CSPRNG.
+///
+/// Ensures that the CSPRNG has been seeded before generating any random bytes,
+/// and will block until it is ready.
+pub fn getrandom(dest: &mut [u8]) -> Result {
+    let res = unsafe { bindings::wait_for_random_bytes() };
+    if res != 0 {
+        return Err(Error::from_kernel_errno(res));
+    }
+
+    unsafe {
+        bindings::get_random_bytes(dest.as_mut_ptr() as *mut core::ffi::c_void, dest.len());
+    }
+    Ok(())
+}
+
+/// Fills a byte slice with random bytes generated from the kernel's CSPRNG.
+///
+/// If the CSPRNG is not yet seeded, returns an `Err(EAGAIN)` immediately.
+pub fn getrandom_nonblock(dest: &mut [u8]) -> Result {
+    if !unsafe { bindings::rng_is_initialized() } {
+        return Err(EAGAIN);
+    }
+    getrandom(dest)
+}
+
+/// Contributes the contents of a byte slice to the kernel's entropy pool.
+///
+/// Does *not* credit the kernel entropy counter though.
+pub fn add_randomness(data: &[u8]) {
+    unsafe {
+        bindings::add_device_randomness(data.as_ptr() as *const core::ffi::c_void, data.len());
+    }
+}
diff --git a/rust/kernel/raw_list.rs b/rust/kernel/raw_list.rs
new file mode 100644
index 000000000000..267b21709c29
--- /dev/null
+++ b/rust/kernel/raw_list.rs
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Raw lists.
+//!
+//! TODO: This module is a work in progress.
+
+use core::{
+    cell::UnsafeCell,
+    ptr,
+    ptr::NonNull,
+    sync::atomic::{AtomicBool, Ordering},
+};
+
+/// A descriptor of list elements.
+///
+/// It describes the type of list elements and provides a function to determine how to get the
+/// links to be used on a list.
+///
+/// A type that may be in multiple lists simultaneously needs to implement one of these for each
+/// simultaneous list.
+pub trait GetLinks {
+    /// The type of the entries in the list.
+    type EntryType: ?Sized;
+
+    /// Returns the links to be used when linking an entry within a list.
+    fn get_links(data: &Self::EntryType) -> &Links<Self::EntryType>;
+}
+
+/// The links used to link an object on a linked list.
+///
+/// Instances of this type are usually embedded in structures and returned in calls to
+/// [`GetLinks::get_links`].
+pub struct Links<T: ?Sized> {
+    inserted: AtomicBool,
+    entry: UnsafeCell<ListEntry<T>>,
+}
+
+impl<T: ?Sized> Links<T> {
+    /// Constructs a new [`Links`] instance that isn't inserted on any lists yet.
+    pub fn new() -> Self {
+        Self {
+            inserted: AtomicBool::new(false),
+            entry: UnsafeCell::new(ListEntry::new()),
+        }
+    }
+
+    fn acquire_for_insertion(&self) -> bool {
+        self.inserted
+            .compare_exchange(false, true, Ordering::Acquire, Ordering::Relaxed)
+            .is_ok()
+    }
+
+    fn release_after_removal(&self) {
+        self.inserted.store(false, Ordering::Release);
+    }
+}
+
+impl<T: ?Sized> Default for Links<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+struct ListEntry<T: ?Sized> {
+    next: Option<NonNull<T>>,
+    prev: Option<NonNull<T>>,
+}
+
+impl<T: ?Sized> ListEntry<T> {
+    fn new() -> Self {
+        Self {
+            next: None,
+            prev: None,
+        }
+    }
+}
+
+/// A linked list.
+///
+/// # Invariants
+///
+/// The links of objects added to a list are owned by the list.
+pub(crate) struct RawList<G: GetLinks> {
+    head: Option<NonNull<G::EntryType>>,
+}
+
+impl<G: GetLinks> RawList<G> {
+    pub(crate) fn new() -> Self {
+        Self { head: None }
+    }
+
+    pub(crate) fn is_empty(&self) -> bool {
+        self.head.is_none()
+    }
+
+    fn insert_after_priv(
+        &mut self,
+        existing: &G::EntryType,
+        new_entry: &mut ListEntry<G::EntryType>,
+        new_ptr: Option<NonNull<G::EntryType>>,
+    ) {
+        {
+            // SAFETY: It's safe to get the previous entry of `existing` because the list cannot
+            // change.
+            let existing_links = unsafe { &mut *G::get_links(existing).entry.get() };
+            new_entry.next = existing_links.next;
+            existing_links.next = new_ptr;
+        }
+
+        new_entry.prev = Some(NonNull::from(existing));
+
+        // SAFETY: It's safe to get the next entry of `existing` because the list cannot change.
+        let next_links =
+            unsafe { &mut *G::get_links(new_entry.next.unwrap().as_ref()).entry.get() };
+        next_links.prev = new_ptr;
+    }
+
+    /// Inserts the given object after `existing`.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `existing` points to a valid entry that is on the list.
+    pub(crate) unsafe fn insert_after(
+        &mut self,
+        existing: &G::EntryType,
+        new: &G::EntryType,
+    ) -> bool {
+        let links = G::get_links(new);
+        if !links.acquire_for_insertion() {
+            // Nothing to do if already inserted.
+            return false;
+        }
+
+        // SAFETY: The links are now owned by the list, so it is safe to get a mutable reference.
+        let new_entry = unsafe { &mut *links.entry.get() };
+        self.insert_after_priv(existing, new_entry, Some(NonNull::from(new)));
+        true
+    }
+
+    fn push_back_internal(&mut self, new: &G::EntryType) -> bool {
+        let links = G::get_links(new);
+        if !links.acquire_for_insertion() {
+            // Nothing to do if already inserted.
+            return false;
+        }
+
+        // SAFETY: The links are now owned by the list, so it is safe to get a mutable reference.
+        let new_entry = unsafe { &mut *links.entry.get() };
+        let new_ptr = Some(NonNull::from(new));
+        match self.back() {
+            // SAFETY: `back` is valid as the list cannot change.
+            Some(back) => self.insert_after_priv(unsafe { back.as_ref() }, new_entry, new_ptr),
+            None => {
+                self.head = new_ptr;
+                new_entry.next = new_ptr;
+                new_entry.prev = new_ptr;
+            }
+        }
+        true
+    }
+
+    pub(crate) unsafe fn push_back(&mut self, new: &G::EntryType) -> bool {
+        self.push_back_internal(new)
+    }
+
+    fn remove_internal(&mut self, data: &G::EntryType) -> bool {
+        let links = G::get_links(data);
+
+        // SAFETY: The links are now owned by the list, so it is safe to get a mutable reference.
+        let entry = unsafe { &mut *links.entry.get() };
+        let next = if let Some(next) = entry.next {
+            next
+        } else {
+            // Nothing to do if the entry is not on the list.
+            return false;
+        };
+
+        if ptr::eq(data, next.as_ptr()) {
+            // We're removing the only element.
+            self.head = None
+        } else {
+            // Update the head if we're removing it.
+            if let Some(raw_head) = self.head {
+                if ptr::eq(data, raw_head.as_ptr()) {
+                    self.head = Some(next);
+                }
+            }
+
+            // SAFETY: It's safe to get the previous entry because the list cannot change.
+            unsafe { &mut *G::get_links(entry.prev.unwrap().as_ref()).entry.get() }.next =
+                entry.next;
+
+            // SAFETY: It's safe to get the next entry because the list cannot change.
+            unsafe { &mut *G::get_links(next.as_ref()).entry.get() }.prev = entry.prev;
+        }
+
+        // Reset the links of the element we're removing so that we know it's not on any list.
+        entry.next = None;
+        entry.prev = None;
+        links.release_after_removal();
+        true
+    }
+
+    /// Removes the given entry.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `data` is either on this list or in no list. It being on another
+    /// list leads to memory unsafety.
+    pub(crate) unsafe fn remove(&mut self, data: &G::EntryType) -> bool {
+        self.remove_internal(data)
+    }
+
+    fn pop_front_internal(&mut self) -> Option<NonNull<G::EntryType>> {
+        let head = self.head?;
+        // SAFETY: The head is on the list as we just got it from there and it cannot change.
+        unsafe { self.remove(head.as_ref()) };
+        Some(head)
+    }
+
+    pub(crate) fn pop_front(&mut self) -> Option<NonNull<G::EntryType>> {
+        self.pop_front_internal()
+    }
+
+    pub(crate) fn front(&self) -> Option<NonNull<G::EntryType>> {
+        self.head
+    }
+
+    pub(crate) fn back(&self) -> Option<NonNull<G::EntryType>> {
+        // SAFETY: The links of head are owned by the list, so it is safe to get a reference.
+        unsafe { &*G::get_links(self.head?.as_ref()).entry.get() }.prev
+    }
+
+    pub(crate) fn cursor_front(&self) -> Cursor<'_, G> {
+        Cursor::new(self, self.front())
+    }
+
+    pub(crate) fn cursor_front_mut(&mut self) -> CursorMut<'_, G> {
+        CursorMut::new(self, self.front())
+    }
+}
+
+struct CommonCursor<G: GetLinks> {
+    cur: Option<NonNull<G::EntryType>>,
+}
+
+impl<G: GetLinks> CommonCursor<G> {
+    fn new(cur: Option<NonNull<G::EntryType>>) -> Self {
+        Self { cur }
+    }
+
+    fn move_next(&mut self, list: &RawList<G>) {
+        match self.cur.take() {
+            None => self.cur = list.head,
+            Some(cur) => {
+                if let Some(head) = list.head {
+                    // SAFETY: We have a shared ref to the linked list, so the links can't change.
+                    let links = unsafe { &*G::get_links(cur.as_ref()).entry.get() };
+                    if links.next.unwrap() != head {
+                        self.cur = links.next;
+                    }
+                }
+            }
+        }
+    }
+
+    fn move_prev(&mut self, list: &RawList<G>) {
+        match list.head {
+            None => self.cur = None,
+            Some(head) => {
+                let next = match self.cur.take() {
+                    None => head,
+                    Some(cur) => {
+                        if cur == head {
+                            return;
+                        }
+                        cur
+                    }
+                };
+                // SAFETY: There's a shared ref to the list, so the links can't change.
+                let links = unsafe { &*G::get_links(next.as_ref()).entry.get() };
+                self.cur = links.prev;
+            }
+        }
+    }
+}
+
+/// A list cursor that allows traversing a linked list and inspecting elements.
+pub struct Cursor<'a, G: GetLinks> {
+    cursor: CommonCursor<G>,
+    list: &'a RawList<G>,
+}
+
+impl<'a, G: GetLinks> Cursor<'a, G> {
+    fn new(list: &'a RawList<G>, cur: Option<NonNull<G::EntryType>>) -> Self {
+        Self {
+            list,
+            cursor: CommonCursor::new(cur),
+        }
+    }
+
+    /// Returns the element the cursor is currently positioned on.
+    pub fn current(&self) -> Option<&'a G::EntryType> {
+        let cur = self.cursor.cur?;
+        // SAFETY: Objects must be kept alive while on the list.
+        Some(unsafe { &*cur.as_ptr() })
+    }
+
+    /// Moves the cursor to the next element.
+    pub fn move_next(&mut self) {
+        self.cursor.move_next(self.list);
+    }
+}
+
+pub(crate) struct CursorMut<'a, G: GetLinks> {
+    cursor: CommonCursor<G>,
+    list: &'a mut RawList<G>,
+}
+
+impl<'a, G: GetLinks> CursorMut<'a, G> {
+    fn new(list: &'a mut RawList<G>, cur: Option<NonNull<G::EntryType>>) -> Self {
+        Self {
+            list,
+            cursor: CommonCursor::new(cur),
+        }
+    }
+
+    pub(crate) fn current(&mut self) -> Option<&mut G::EntryType> {
+        let cur = self.cursor.cur?;
+        // SAFETY: Objects must be kept alive while on the list.
+        Some(unsafe { &mut *cur.as_ptr() })
+    }
+
+    /// Removes the entry the cursor is pointing to and advances the cursor to the next entry. It
+    /// returns a raw pointer to the removed element (if one is removed).
+    pub(crate) fn remove_current(&mut self) -> Option<NonNull<G::EntryType>> {
+        let entry = self.cursor.cur?;
+        self.cursor.move_next(self.list);
+        // SAFETY: The entry is on the list as we just got it from there and it cannot change.
+        unsafe { self.list.remove(entry.as_ref()) };
+        Some(entry)
+    }
+
+    pub(crate) fn peek_next(&mut self) -> Option<&mut G::EntryType> {
+        let mut new = CommonCursor::new(self.cursor.cur);
+        new.move_next(self.list);
+        // SAFETY: Objects must be kept alive while on the list.
+        Some(unsafe { &mut *new.cur?.as_ptr() })
+    }
+
+    pub(crate) fn peek_prev(&mut self) -> Option<&mut G::EntryType> {
+        let mut new = CommonCursor::new(self.cursor.cur);
+        new.move_prev(self.list);
+        // SAFETY: Objects must be kept alive while on the list.
+        Some(unsafe { &mut *new.cur?.as_ptr() })
+    }
+
+    pub(crate) fn move_next(&mut self) {
+        self.cursor.move_next(self.list);
+    }
+}
diff --git a/rust/kernel/rbtree.rs b/rust/kernel/rbtree.rs
new file mode 100644
index 000000000000..a30739cc6839
--- /dev/null
+++ b/rust/kernel/rbtree.rs
@@ -0,0 +1,563 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Red-black trees.
+//!
+//! C header: [`include/linux/rbtree.h`](../../../../include/linux/rbtree.h)
+//!
+//! Reference: <https://www.kernel.org/doc/html/latest/core-api/rbtree.html>
+
+use crate::{bindings, Result};
+use alloc::boxed::Box;
+use core::{
+    cmp::{Ord, Ordering},
+    iter::{IntoIterator, Iterator},
+    marker::PhantomData,
+    mem::MaybeUninit,
+    ptr::{addr_of_mut, NonNull},
+};
+
+struct Node<K, V> {
+    links: bindings::rb_node,
+    key: K,
+    value: V,
+}
+
+/// A red-black tree with owned nodes.
+///
+/// It is backed by the kernel C red-black trees.
+///
+/// # Invariants
+///
+/// Non-null parent/children pointers stored in instances of the `rb_node` C struct are always
+/// valid, and pointing to a field of our internal representation of a node.
+///
+/// # Examples
+///
+/// In the example below we do several operations on a tree. We note that insertions may fail if
+/// the system is out of memory.
+///
+/// ```
+/// use kernel::rbtree::RBTree;
+///
+/// # fn test() -> Result {
+/// // Create a new tree.
+/// let mut tree = RBTree::new();
+///
+/// // Insert three elements.
+/// tree.try_insert(20, 200)?;
+/// tree.try_insert(10, 100)?;
+/// tree.try_insert(30, 300)?;
+///
+/// // Check the nodes we just inserted.
+/// {
+///     let mut iter = tree.iter();
+///     assert_eq!(iter.next().unwrap(), (&10, &100));
+///     assert_eq!(iter.next().unwrap(), (&20, &200));
+///     assert_eq!(iter.next().unwrap(), (&30, &300));
+///     assert!(iter.next().is_none());
+/// }
+///
+/// // Print all elements.
+/// for (key, value) in &tree {
+///     pr_info!("{} = {}\n", key, value);
+/// }
+///
+/// // Replace one of the elements.
+/// tree.try_insert(10, 1000)?;
+///
+/// // Check that the tree reflects the replacement.
+/// {
+///     let mut iter = tree.iter();
+///     assert_eq!(iter.next().unwrap(), (&10, &1000));
+///     assert_eq!(iter.next().unwrap(), (&20, &200));
+///     assert_eq!(iter.next().unwrap(), (&30, &300));
+///     assert!(iter.next().is_none());
+/// }
+///
+/// // Change the value of one of the elements.
+/// *tree.get_mut(&30).unwrap() = 3000;
+///
+/// // Check that the tree reflects the update.
+/// {
+///     let mut iter = tree.iter();
+///     assert_eq!(iter.next().unwrap(), (&10, &1000));
+///     assert_eq!(iter.next().unwrap(), (&20, &200));
+///     assert_eq!(iter.next().unwrap(), (&30, &3000));
+///     assert!(iter.next().is_none());
+/// }
+///
+/// // Remove an element.
+/// tree.remove(&10);
+///
+/// // Check that the tree reflects the removal.
+/// {
+///     let mut iter = tree.iter();
+///     assert_eq!(iter.next().unwrap(), (&20, &200));
+///     assert_eq!(iter.next().unwrap(), (&30, &3000));
+///     assert!(iter.next().is_none());
+/// }
+///
+/// // Update all values.
+/// for value in tree.values_mut() {
+///     *value *= 10;
+/// }
+///
+/// // Check that the tree reflects the changes to values.
+/// {
+///     let mut iter = tree.iter();
+///     assert_eq!(iter.next().unwrap(), (&20, &2000));
+///     assert_eq!(iter.next().unwrap(), (&30, &30000));
+///     assert!(iter.next().is_none());
+/// }
+///
+/// # Ok(())
+/// # }
+/// #
+/// # assert_eq!(test(), Ok(()));
+/// ```
+///
+/// In the example below, we first allocate a node, acquire a spinlock, then insert the node into
+/// the tree. This is useful when the insertion context does not allow sleeping, for example, when
+/// holding a spinlock.
+///
+/// ```
+/// use kernel::{rbtree::RBTree, sync::SpinLock};
+///
+/// fn insert_test(tree: &SpinLock<RBTree<u32, u32>>) -> Result {
+///     // Pre-allocate node. This may fail (as it allocates memory).
+///     let node = RBTree::try_allocate_node(10, 100)?;
+///
+///     // Insert node while holding the lock. It is guaranteed to succeed with no allocation
+///     // attempts.
+///     let mut guard = tree.lock();
+///     guard.insert(node);
+///     Ok(())
+/// }
+/// ```
+///
+/// In the example below, we reuse an existing node allocation from an element we removed.
+///
+/// ```
+/// use kernel::rbtree::RBTree;
+///
+/// # fn test() -> Result {
+/// // Create a new tree.
+/// let mut tree = RBTree::new();
+///
+/// // Insert three elements.
+/// tree.try_insert(20, 200)?;
+/// tree.try_insert(10, 100)?;
+/// tree.try_insert(30, 300)?;
+///
+/// // Check the nodes we just inserted.
+/// {
+///     let mut iter = tree.iter();
+///     assert_eq!(iter.next().unwrap(), (&10, &100));
+///     assert_eq!(iter.next().unwrap(), (&20, &200));
+///     assert_eq!(iter.next().unwrap(), (&30, &300));
+///     assert!(iter.next().is_none());
+/// }
+///
+/// // Remove a node, getting back ownership of it.
+/// let existing = tree.remove_node(&30).unwrap();
+///
+/// // Check that the tree reflects the removal.
+/// {
+///     let mut iter = tree.iter();
+///     assert_eq!(iter.next().unwrap(), (&10, &100));
+///     assert_eq!(iter.next().unwrap(), (&20, &200));
+///     assert!(iter.next().is_none());
+/// }
+///
+/// // Turn the node into a reservation so that we can reuse it with a different key/value.
+/// let reservation = existing.into_reservation();
+///
+/// // Insert a new node into the tree, reusing the previous allocation. This is guaranteed to
+/// // succeed (no memory allocations).
+/// tree.insert(reservation.into_node(15, 150));
+///
+/// // Check that the tree reflect the new insertion.
+/// {
+///     let mut iter = tree.iter();
+///     assert_eq!(iter.next().unwrap(), (&10, &100));
+///     assert_eq!(iter.next().unwrap(), (&15, &150));
+///     assert_eq!(iter.next().unwrap(), (&20, &200));
+///     assert!(iter.next().is_none());
+/// }
+///
+/// # Ok(())
+/// # }
+/// #
+/// # assert_eq!(test(), Ok(()));
+/// ```
+pub struct RBTree<K, V> {
+    root: bindings::rb_root,
+    _p: PhantomData<Node<K, V>>,
+}
+
+impl<K, V> RBTree<K, V> {
+    /// Creates a new and empty tree.
+    pub fn new() -> Self {
+        Self {
+            // INVARIANT: There are no nodes in the tree, so the invariant holds vacuously.
+            root: bindings::rb_root::default(),
+            _p: PhantomData,
+        }
+    }
+
+    /// Tries to insert a new value into the tree.
+    ///
+    /// It overwrites a node if one already exists with the same key and returns it (containing the
+    /// key/value pair). Returns [`None`] if a node with the same key didn't already exist.
+    ///
+    /// Returns an error if it cannot allocate memory for the new node.
+    pub fn try_insert(&mut self, key: K, value: V) -> Result<Option<RBTreeNode<K, V>>>
+    where
+        K: Ord,
+    {
+        Ok(self.insert(Self::try_allocate_node(key, value)?))
+    }
+
+    /// Allocates memory for a node to be eventually initialised and inserted into the tree via a
+    /// call to [`RBTree::insert`].
+    pub fn try_reserve_node() -> Result<RBTreeNodeReservation<K, V>> {
+        Ok(RBTreeNodeReservation {
+            node: Box::try_new(MaybeUninit::uninit())?,
+        })
+    }
+
+    /// Allocates and initialiases a node that can be inserted into the tree via
+    /// [`RBTree::insert`].
+    pub fn try_allocate_node(key: K, value: V) -> Result<RBTreeNode<K, V>> {
+        Ok(Self::try_reserve_node()?.into_node(key, value))
+    }
+
+    /// Inserts a new node into the tree.
+    ///
+    /// It overwrites a node if one already exists with the same key and returns it (containing the
+    /// key/value pair). Returns [`None`] if a node with the same key didn't already exist.
+    ///
+    /// This function always succeeds.
+    pub fn insert(&mut self, node: RBTreeNode<K, V>) -> Option<RBTreeNode<K, V>>
+    where
+        K: Ord,
+    {
+        let RBTreeNode { node } = node;
+        let node = Box::into_raw(node);
+        // SAFETY: `node` is valid at least until we call `Box::from_raw`, which only happens when
+        // the node is removed or replaced.
+        let node_links = unsafe { addr_of_mut!((*node).links) };
+        let mut new_link: &mut *mut bindings::rb_node = &mut self.root.rb_node;
+        let mut parent = core::ptr::null_mut();
+        while !new_link.is_null() {
+            let this = crate::container_of!(*new_link, Node<K, V>, links);
+
+            parent = *new_link;
+
+            // SAFETY: `this` is a non-null node so it is valid by the type invariants. `node` is
+            // valid until the node is removed.
+            match unsafe { (*node).key.cmp(&(*this).key) } {
+                // SAFETY: `parent` is a non-null node so it is valid by the type invariants.
+                Ordering::Less => new_link = unsafe { &mut (*parent).rb_left },
+                // SAFETY: `parent` is a non-null node so it is valid by the type invariants.
+                Ordering::Greater => new_link = unsafe { &mut (*parent).rb_right },
+                Ordering::Equal => {
+                    // INVARIANT: We are replacing an existing node with a new one, which is valid.
+                    // It remains valid because we "forgot" it with `Box::into_raw`.
+                    // SAFETY: All pointers are non-null and valid (parent, despite the name, really
+                    // is the node we're replacing).
+                    unsafe { bindings::rb_replace_node(parent, node_links, &mut self.root) };
+
+                    // INVARIANT: The node is being returned and the caller may free it, however,
+                    // it was removed from the tree. So the invariants still hold.
+                    return Some(RBTreeNode {
+                        // SAFETY: `this` was a node in the tree, so it is valid.
+                        node: unsafe { Box::from_raw(this as _) },
+                    });
+                }
+            }
+        }
+
+        // INVARIANT: We are linking in a new node, which is valid. It remains valid because we
+        // "forgot" it with `Box::into_raw`.
+        // SAFETY: All pointers are non-null and valid (`*new_link` is null, but `new_link` is a
+        // mutable reference).
+        unsafe { bindings::rb_link_node(node_links, parent, new_link) };
+
+        // SAFETY: All pointers are valid. `node` has just been inserted into the tree.
+        unsafe { bindings::rb_insert_color(node_links, &mut self.root) };
+        None
+    }
+
+    /// Returns a node with the given key, if one exists.
+    fn find(&self, key: &K) -> Option<NonNull<Node<K, V>>>
+    where
+        K: Ord,
+    {
+        let mut node = self.root.rb_node;
+        while !node.is_null() {
+            let this = crate::container_of!(node, Node<K, V>, links);
+            // SAFETY: `this` is a non-null node so it is valid by the type invariants.
+            node = match key.cmp(unsafe { &(*this).key }) {
+                // SAFETY: `node` is a non-null node so it is valid by the type invariants.
+                Ordering::Less => unsafe { (*node).rb_left },
+                // SAFETY: `node` is a non-null node so it is valid by the type invariants.
+                Ordering::Greater => unsafe { (*node).rb_right },
+                Ordering::Equal => return NonNull::new(this as _),
+            }
+        }
+        None
+    }
+
+    /// Returns a reference to the value corresponding to the key.
+    pub fn get(&self, key: &K) -> Option<&V>
+    where
+        K: Ord,
+    {
+        // SAFETY: The `find` return value is a node in the tree, so it is valid.
+        self.find(key).map(|node| unsafe { &node.as_ref().value })
+    }
+
+    /// Returns a mutable reference to the value corresponding to the key.
+    pub fn get_mut(&mut self, key: &K) -> Option<&mut V>
+    where
+        K: Ord,
+    {
+        // SAFETY: The `find` return value is a node in the tree, so it is valid.
+        self.find(key)
+            .map(|mut node| unsafe { &mut node.as_mut().value })
+    }
+
+    /// Removes the node with the given key from the tree.
+    ///
+    /// It returns the node that was removed if one exists, or [`None`] otherwise.
+    pub fn remove_node(&mut self, key: &K) -> Option<RBTreeNode<K, V>>
+    where
+        K: Ord,
+    {
+        let mut node = self.find(key)?;
+
+        // SAFETY: The `find` return value is a node in the tree, so it is valid.
+        unsafe { bindings::rb_erase(&mut node.as_mut().links, &mut self.root) };
+
+        // INVARIANT: The node is being returned and the caller may free it, however, it was
+        // removed from the tree. So the invariants still hold.
+        Some(RBTreeNode {
+            // SAFETY: The `find` return value was a node in the tree, so it is valid.
+            node: unsafe { Box::from_raw(node.as_ptr()) },
+        })
+    }
+
+    /// Removes the node with the given key from the tree.
+    ///
+    /// It returns the value that was removed if one exists, or [`None`] otherwise.
+    pub fn remove(&mut self, key: &K) -> Option<V>
+    where
+        K: Ord,
+    {
+        let node = self.remove_node(key)?;
+        let RBTreeNode { node } = node;
+        let Node {
+            links: _,
+            key: _,
+            value,
+        } = *node;
+        Some(value)
+    }
+
+    /// Returns an iterator over the tree nodes, sorted by key.
+    pub fn iter(&self) -> RBTreeIterator<'_, K, V> {
+        RBTreeIterator {
+            _tree: PhantomData,
+            // SAFETY: `root` is valid as it's embedded in `self` and we have a valid `self`.
+            next: unsafe { bindings::rb_first(&self.root) },
+        }
+    }
+
+    /// Returns a mutable iterator over the tree nodes, sorted by key.
+    pub fn iter_mut(&mut self) -> RBTreeIteratorMut<'_, K, V> {
+        RBTreeIteratorMut {
+            _tree: PhantomData,
+            // SAFETY: `root` is valid as it's embedded in `self` and we have a valid `self`.
+            next: unsafe { bindings::rb_first(&self.root) },
+        }
+    }
+
+    /// Returns an iterator over the keys of the nodes in the tree, in sorted order.
+    pub fn keys(&self) -> impl Iterator<Item = &'_ K> {
+        self.iter().map(|(k, _)| k)
+    }
+
+    /// Returns an iterator over the values of the nodes in the tree, sorted by key.
+    pub fn values(&self) -> impl Iterator<Item = &'_ V> {
+        self.iter().map(|(_, v)| v)
+    }
+
+    /// Returns a mutable iterator over the values of the nodes in the tree, sorted by key.
+    pub fn values_mut(&mut self) -> impl Iterator<Item = &'_ mut V> {
+        self.iter_mut().map(|(_, v)| v)
+    }
+}
+
+impl<K, V> Default for RBTree<K, V> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<K, V> Drop for RBTree<K, V> {
+    fn drop(&mut self) {
+        // SAFETY: `root` is valid as it's embedded in `self` and we have a valid `self`.
+        let mut next = unsafe { bindings::rb_first_postorder(&self.root) };
+
+        // INVARIANT: The loop invariant is that all tree nodes from `next` in postorder are valid.
+        while !next.is_null() {
+            let this = crate::container_of!(next, Node<K, V>, links);
+
+            // Find out what the next node is before disposing of the current one.
+            // SAFETY: `next` and all nodes in postorder are still valid.
+            next = unsafe { bindings::rb_next_postorder(next) };
+
+            // INVARIANT: This is the destructor, so we break the type invariant during clean-up,
+            // but it is not observable. The loop invariant is still maintained.
+            // SAFETY: `this` is valid per the loop invariant.
+            unsafe { Box::from_raw(this as *mut Node<K, V>) };
+        }
+    }
+}
+
+impl<'a, K, V> IntoIterator for &'a RBTree<K, V> {
+    type Item = (&'a K, &'a V);
+    type IntoIter = RBTreeIterator<'a, K, V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter()
+    }
+}
+
+/// An iterator over the nodes of a [`RBTree`].
+///
+/// Instances are created by calling [`RBTree::iter`].
+pub struct RBTreeIterator<'a, K, V> {
+    _tree: PhantomData<&'a RBTree<K, V>>,
+    next: *mut bindings::rb_node,
+}
+
+impl<'a, K, V> Iterator for RBTreeIterator<'a, K, V> {
+    type Item = (&'a K, &'a V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.next.is_null() {
+            return None;
+        }
+
+        let cur = crate::container_of!(self.next, Node<K, V>, links);
+
+        // SAFETY: The reference to the tree used to create the iterator outlives the iterator, so
+        // the tree cannot change. By the tree invariant, all nodes are valid.
+        self.next = unsafe { bindings::rb_next(self.next) };
+
+        // SAFETY: By the same reasoning above, it is safe to dereference the node. Additionally,
+        // it is ok to return a reference to members because the iterator must outlive it.
+        Some(unsafe { (&(*cur).key, &(*cur).value) })
+    }
+}
+
+impl<'a, K, V> IntoIterator for &'a mut RBTree<K, V> {
+    type Item = (&'a K, &'a mut V);
+    type IntoIter = RBTreeIteratorMut<'a, K, V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter_mut()
+    }
+}
+
+/// A mutable iterator over the nodes of a [`RBTree`].
+///
+/// Instances are created by calling [`RBTree::iter_mut`].
+pub struct RBTreeIteratorMut<'a, K, V> {
+    _tree: PhantomData<&'a RBTree<K, V>>,
+    next: *mut bindings::rb_node,
+}
+
+impl<'a, K, V> Iterator for RBTreeIteratorMut<'a, K, V> {
+    type Item = (&'a K, &'a mut V);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.next.is_null() {
+            return None;
+        }
+
+        let cur = crate::container_of!(self.next, Node<K, V>, links) as *mut Node<K, V>;
+
+        // SAFETY: The reference to the tree used to create the iterator outlives the iterator, so
+        // the tree cannot change (except for the value of previous nodes, but those don't affect
+        // the iteration process). By the tree invariant, all nodes are valid.
+        self.next = unsafe { bindings::rb_next(self.next) };
+
+        // SAFETY: By the same reasoning above, it is safe to dereference the node. Additionally,
+        // it is ok to return a reference to members because the iterator must outlive it.
+        Some(unsafe { (&(*cur).key, &mut (*cur).value) })
+    }
+}
+
+/// A memory reservation for a red-black tree node.
+///
+/// It contains the memory needed to hold a node that can be inserted into a red-black tree. One
+/// can be obtained by directly allocating it ([`RBTree::try_reserve_node`]) or by "uninitialising"
+/// ([`RBTreeNode::into_reservation`]) an actual node (usually returned by some operation like
+/// removal from a tree).
+pub struct RBTreeNodeReservation<K, V> {
+    node: Box<MaybeUninit<Node<K, V>>>,
+}
+
+impl<K, V> RBTreeNodeReservation<K, V> {
+    /// Initialises a node reservation.
+    ///
+    /// It then becomes an [`RBTreeNode`] that can be inserted into a tree.
+    pub fn into_node(mut self, key: K, value: V) -> RBTreeNode<K, V> {
+        let node_ptr = self.node.as_mut_ptr();
+        // SAFETY: `node_ptr` is valid, and so are its fields.
+        unsafe { addr_of_mut!((*node_ptr).links).write(bindings::rb_node::default()) };
+        // SAFETY: `node_ptr` is valid, and so are its fields.
+        unsafe { addr_of_mut!((*node_ptr).key).write(key) };
+        // SAFETY: `node_ptr` is valid, and so are its fields.
+        unsafe { addr_of_mut!((*node_ptr).value).write(value) };
+        let raw = Box::into_raw(self.node);
+        RBTreeNode {
+            // SAFETY: The pointer came from a `MaybeUninit<Node>` whose fields have all been
+            // initialised. Additionally, it has the same layout as `Node`.
+            node: unsafe { Box::from_raw(raw as _) },
+        }
+    }
+}
+
+/// A red-black tree node.
+///
+/// The node is fully initialised (with key and value) and can be inserted into a tree without any
+/// extra allocations or failure paths.
+pub struct RBTreeNode<K, V> {
+    node: Box<Node<K, V>>,
+}
+
+impl<K, V> RBTreeNode<K, V> {
+    /// "Uninitialises" a node.
+    ///
+    /// It then becomes a reservation that can be re-initialised into a different node (i.e., with
+    /// a different key and/or value).
+    ///
+    /// The existing key and value are dropped in-place as part of this operation, that is, memory
+    /// may be freed (but only for the key/value; memory for the node itself is kept for reuse).
+    pub fn into_reservation(self) -> RBTreeNodeReservation<K, V> {
+        let raw = Box::into_raw(self.node);
+        let mut ret = RBTreeNodeReservation {
+            // SAFETY: The pointer came from a valid `Node`, which has the same layout as
+            // `MaybeUninit<Node>`.
+            node: unsafe { Box::from_raw(raw as _) },
+        };
+        // SAFETY: Although the type is `MaybeUninit<Node>`, we know it has been initialised
+        // because it came from a `Node`. So it is safe to drop it.
+        unsafe { core::ptr::drop_in_place(ret.node.as_mut_ptr()) };
+        ret
+    }
+}
diff --git a/rust/kernel/revocable.rs b/rust/kernel/revocable.rs
new file mode 100644
index 000000000000..1093c4d26026
--- /dev/null
+++ b/rust/kernel/revocable.rs
@@ -0,0 +1,425 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Revocable objects.
+//!
+//! The [`Revocable`] type wraps other types and allows access to them to be revoked. The existence
+//! of a [`RevocableGuard`] ensures that objects remain valid.
+
+use crate::{bindings, sync::rcu};
+use core::{
+    cell::UnsafeCell,
+    marker::PhantomData,
+    mem::MaybeUninit,
+    ops::Deref,
+    ptr::drop_in_place,
+    sync::atomic::{fence, AtomicBool, AtomicU32, Ordering},
+};
+
+/// An object that can become inaccessible at runtime.
+///
+/// Once access is revoked and all concurrent users complete (i.e., all existing instances of
+/// [`RevocableGuard`] are dropped), the wrapped object is also dropped.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::revocable::Revocable;
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// fn add_two(v: &Revocable<Example>) -> Option<u32> {
+///     let guard = v.try_access()?;
+///     Some(guard.a + guard.b)
+/// }
+///
+/// let v = Revocable::new(Example { a: 10, b: 20 });
+/// assert_eq!(add_two(&v), Some(30));
+/// v.revoke();
+/// assert_eq!(add_two(&v), None);
+/// ```
+///
+/// Sample example as above, but explicitly using the rcu read side lock.
+///
+/// ```
+/// # use kernel::revocable::Revocable;
+/// use kernel::sync::rcu;
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// fn add_two(v: &Revocable<Example>) -> Option<u32> {
+///     let guard = rcu::read_lock();
+///     let e = v.try_access_with_guard(&guard)?;
+///     Some(e.a + e.b)
+/// }
+///
+/// let v = Revocable::new(Example { a: 10, b: 20 });
+/// assert_eq!(add_two(&v), Some(30));
+/// v.revoke();
+/// assert_eq!(add_two(&v), None);
+/// ```
+pub struct Revocable<T> {
+    is_available: AtomicBool,
+    data: MaybeUninit<UnsafeCell<T>>,
+}
+
+// SAFETY: `Revocable` is `Send` if the wrapped object is also `Send`. This is because while the
+// functionality exposed by `Revocable` can be accessed from any thread/CPU, it is possible that
+// this isn't supported by the wrapped object.
+unsafe impl<T: Send> Send for Revocable<T> {}
+
+// SAFETY: `Revocable` is `Sync` if the wrapped object is both `Send` and `Sync`. We require `Send`
+// from the wrapped object as well because  of `Revocable::revoke`, which can trigger the `Drop`
+// implementation of the wrapped object from an arbitrary thread.
+unsafe impl<T: Sync + Send> Sync for Revocable<T> {}
+
+impl<T> Revocable<T> {
+    /// Creates a new revocable instance of the given data.
+    pub const fn new(data: T) -> Self {
+        Self {
+            is_available: AtomicBool::new(true),
+            data: MaybeUninit::new(UnsafeCell::new(data)),
+        }
+    }
+
+    /// Tries to access the \[revocable\] wrapped object.
+    ///
+    /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+    ///
+    /// Returns a guard that gives access to the object otherwise; the object is guaranteed to
+    /// remain accessible while the guard is alive. In such cases, callers are not allowed to sleep
+    /// because another CPU may be waiting to complete the revocation of this object.
+    pub fn try_access(&self) -> Option<RevocableGuard<'_, T>> {
+        let guard = rcu::read_lock();
+        if self.is_available.load(Ordering::Relaxed) {
+            // SAFETY: Since `self.is_available` is true, data is initialised and has to remain
+            // valid because the RCU read side lock prevents it from being dropped.
+            Some(unsafe { RevocableGuard::new(self.data.assume_init_ref().get(), guard) })
+        } else {
+            None
+        }
+    }
+
+    /// Tries to access the \[revocable\] wrapped object.
+    ///
+    /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+    ///
+    /// Returns a shared reference to the object otherwise; the object is guaranteed to
+    /// remain accessible while the rcu read side guard is alive. In such cases, callers are not
+    /// allowed to sleep because another CPU may be waiting to complete the revocation of this
+    /// object.
+    pub fn try_access_with_guard<'a>(&'a self, _guard: &'a rcu::Guard) -> Option<&'a T> {
+        if self.is_available.load(Ordering::Relaxed) {
+            // SAFETY: Since `self.is_available` is true, data is initialised and has to remain
+            // valid because the RCU read side lock prevents it from being dropped.
+            Some(unsafe { &*self.data.assume_init_ref().get() })
+        } else {
+            None
+        }
+    }
+
+    /// Revokes access to and drops the wrapped object.
+    ///
+    /// Access to the object is revoked immediately to new callers of [`Revocable::try_access`]. If
+    /// there are concurrent users of the object (i.e., ones that called [`Revocable::try_access`]
+    /// beforehand and still haven't dropped the returned guard), this function waits for the
+    /// concurrent access to complete before dropping the wrapped object.
+    pub fn revoke(&self) {
+        if self
+            .is_available
+            .compare_exchange(true, false, Ordering::Relaxed, Ordering::Relaxed)
+            .is_ok()
+        {
+            // SAFETY: Just an FFI call, there are no further requirements.
+            unsafe { bindings::synchronize_rcu() };
+
+            // SAFETY: We know `self.data` is valid because only one CPU can succeed the
+            // `compare_exchange` above that takes `is_available` from `true` to `false`.
+            unsafe { drop_in_place(self.data.assume_init_ref().get()) };
+        }
+    }
+}
+
+impl<T> Drop for Revocable<T> {
+    fn drop(&mut self) {
+        // Drop only if the data hasn't been revoked yet (in which case it has already been
+        // dropped).
+        if *self.is_available.get_mut() {
+            // SAFETY: We know `self.data` is valid because no other CPU has changed
+            // `is_available` to `false` yet, and no other CPU can do it anymore because this CPU
+            // holds the only reference (mutable) to `self` now.
+            unsafe { drop_in_place(self.data.assume_init_ref().get()) };
+        }
+    }
+}
+
+/// A guard that allows access to a revocable object and keeps it alive.
+///
+/// CPUs may not sleep while holding on to [`RevocableGuard`] because it's in atomic context
+/// holding the RCU read-side lock.
+///
+/// # Invariants
+///
+/// The RCU read-side lock is held while the guard is alive.
+pub struct RevocableGuard<'a, T> {
+    data_ref: *const T,
+    _rcu_guard: rcu::Guard,
+    _p: PhantomData<&'a ()>,
+}
+
+impl<T> RevocableGuard<'_, T> {
+    fn new(data_ref: *const T, rcu_guard: rcu::Guard) -> Self {
+        Self {
+            data_ref,
+            _rcu_guard: rcu_guard,
+            _p: PhantomData,
+        }
+    }
+}
+
+impl<T> Deref for RevocableGuard<'_, T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: By the type invariants, we hold the rcu read-side lock, so the object is
+        // guaranteed to remain valid.
+        unsafe { &*self.data_ref }
+    }
+}
+
+/// An object that can become inaccessible at runtime.
+///
+/// Once access is revoked and all concurrent users complete (i.e., all existing instances of
+/// [`AsyncRevocableGuard`] are dropped), the wrapped object is also dropped.
+///
+/// Unlike [`Revocable`], [`AsyncRevocable`] does not wait for concurrent users of the wrapped
+/// object to finish before [`AsyncRevocable::revoke`] completes -- thus the async qualifier. This
+/// has the advantage of not requiring RCU locks or waits of any kind.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::revocable::AsyncRevocable;
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// fn add_two(v: &AsyncRevocable<Example>) -> Option<u32> {
+///     let guard = v.try_access()?;
+///     Some(guard.a + guard.b)
+/// }
+///
+/// let v = AsyncRevocable::new(Example { a: 10, b: 20 });
+/// assert_eq!(add_two(&v), Some(30));
+/// v.revoke();
+/// assert_eq!(add_two(&v), None);
+/// ```
+///
+/// Example where revocation happens while there is a user:
+///
+/// ```
+/// # use kernel::revocable::AsyncRevocable;
+/// use core::sync::atomic::{AtomicBool, Ordering};
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// static DROPPED: AtomicBool = AtomicBool::new(false);
+///
+/// impl Drop for Example {
+///     fn drop(&mut self) {
+///         DROPPED.store(true, Ordering::Relaxed);
+///     }
+/// }
+///
+/// fn add_two(v: &AsyncRevocable<Example>) -> Option<u32> {
+///     let guard = v.try_access()?;
+///     Some(guard.a + guard.b)
+/// }
+///
+/// let v = AsyncRevocable::new(Example { a: 10, b: 20 });
+/// assert_eq!(add_two(&v), Some(30));
+///
+/// let guard = v.try_access().unwrap();
+/// assert!(!v.is_revoked());
+/// assert!(!DROPPED.load(Ordering::Relaxed));
+/// v.revoke();
+/// assert!(!DROPPED.load(Ordering::Relaxed));
+/// assert!(v.is_revoked());
+/// assert!(v.try_access().is_none());
+/// assert_eq!(guard.a + guard.b, 30);
+/// drop(guard);
+/// assert!(DROPPED.load(Ordering::Relaxed));
+/// ```
+pub struct AsyncRevocable<T> {
+    usage_count: AtomicU32,
+    data: MaybeUninit<UnsafeCell<T>>,
+}
+
+// SAFETY: `AsyncRevocable` is `Send` if the wrapped object is also `Send`. This is because while
+// the functionality exposed by `AsyncRevocable` can be accessed from any thread/CPU, it is
+// possible that this isn't supported by the wrapped object.
+unsafe impl<T: Send> Send for AsyncRevocable<T> {}
+
+// SAFETY: `AsyncRevocable` is `Sync` if the wrapped object is both `Send` and `Sync`. We require
+// `Send` from the wrapped object as well because  of `AsyncRevocable::revoke`, which can trigger
+// the `Drop` implementation of the wrapped object from an arbitrary thread.
+unsafe impl<T: Sync + Send> Sync for AsyncRevocable<T> {}
+
+const REVOKED: u32 = 0x80000000;
+const COUNT_MASK: u32 = !REVOKED;
+const SATURATED_COUNT: u32 = REVOKED - 1;
+
+impl<T> AsyncRevocable<T> {
+    /// Creates a new asynchronously revocable instance of the given data.
+    pub fn new(data: T) -> Self {
+        Self {
+            usage_count: AtomicU32::new(0),
+            data: MaybeUninit::new(UnsafeCell::new(data)),
+        }
+    }
+
+    /// Tries to access the \[revocable\] wrapped object.
+    ///
+    /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+    ///
+    /// Returns a guard that gives access to the object otherwise; the object is guaranteed to
+    /// remain accessible while the guard is alive.
+    pub fn try_access(&self) -> Option<AsyncRevocableGuard<'_, T>> {
+        loop {
+            let count = self.usage_count.load(Ordering::Relaxed);
+
+            // Fail attempt to access if the object is already revoked.
+            if count & REVOKED != 0 {
+                return None;
+            }
+
+            // No need to increment if the count is saturated.
+            if count == SATURATED_COUNT
+                || self
+                    .usage_count
+                    .compare_exchange(count, count + 1, Ordering::Relaxed, Ordering::Relaxed)
+                    .is_ok()
+            {
+                return Some(AsyncRevocableGuard { revocable: self });
+            }
+        }
+    }
+
+    /// Revokes access to the protected object.
+    ///
+    /// Returns `true` if access has been revoked, or `false` when the object has already been
+    /// revoked by a previous call to [`AsyncRevocable::revoke`].
+    ///
+    /// This call is non-blocking, that is, no new users of the revocable object will be allowed,
+    /// but potential current users are able to continue to use it and the thread won't wait for
+    /// them to finish. In such cases, the object will be dropped when the last user completes.
+    pub fn revoke(&self) -> bool {
+        // Set the `REVOKED` bit.
+        //
+        // The acquire barrier matches up with the release when decrementing the usage count.
+        let prev = self.usage_count.fetch_or(REVOKED, Ordering::Acquire);
+        if prev & REVOKED != 0 {
+            // Another thread already revoked this object.
+            return false;
+        }
+
+        if prev == 0 {
+            // SAFETY: This thread just revoked the object and the usage count is zero, so the
+            // object is valid and there will be no future users.
+            unsafe { drop_in_place(UnsafeCell::raw_get(self.data.as_ptr())) };
+        }
+
+        true
+    }
+
+    /// Returns whether access to the object has been revoked.
+    pub fn is_revoked(&self) -> bool {
+        self.usage_count.load(Ordering::Relaxed) & REVOKED != 0
+    }
+}
+
+impl<T> Drop for AsyncRevocable<T> {
+    fn drop(&mut self) {
+        let count = *self.usage_count.get_mut();
+        if count != REVOKED {
+            // The object hasn't been dropped yet, so we do it now.
+
+            // This matches with the release when decrementing the usage count.
+            fence(Ordering::Acquire);
+
+            // SAFETY: Since `count` is does not indicate a count of 0 and the REVOKED bit set, the
+            // object is still valid.
+            unsafe { drop_in_place(UnsafeCell::raw_get(self.data.as_ptr())) };
+        }
+    }
+}
+
+/// A guard that allows access to a revocable object and keeps it alive.
+///
+/// # Invariants
+///
+/// The owner owns an increment on the usage count (which may have saturated it), which keeps the
+/// revocable object alive.
+pub struct AsyncRevocableGuard<'a, T> {
+    revocable: &'a AsyncRevocable<T>,
+}
+
+impl<T> Deref for AsyncRevocableGuard<'_, T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: The type invariants guarantee that the caller owns an increment.
+        unsafe { &*self.revocable.data.assume_init_ref().get() }
+    }
+}
+
+impl<T> Drop for AsyncRevocableGuard<'_, T> {
+    fn drop(&mut self) {
+        loop {
+            let count = self.revocable.usage_count.load(Ordering::Relaxed);
+            let actual_count = count & COUNT_MASK;
+            if actual_count == SATURATED_COUNT {
+                // The count is saturated, so we won't decrement (nor do we drop the object).
+                return;
+            }
+
+            if actual_count == 0 {
+                // Trying to underflow the count.
+                panic!("actual_count is zero");
+            }
+
+            // On success, we use release ordering, which matches with the acquire in one of the
+            // places where we drop the object, namely: below, in `AsyncRevocable::revoke`, or in
+            // `AsyncRevocable::drop`.
+            if self
+                .revocable
+                .usage_count
+                .compare_exchange(count, count - 1, Ordering::Release, Ordering::Relaxed)
+                .is_ok()
+            {
+                if count == 1 | REVOKED {
+                    // `count`  is now zero and it is revoked, so free it now.
+
+                    // This matches with the release above (which may have happened in other
+                    // threads concurrently).
+                    fence(Ordering::Acquire);
+
+                    // SAFETY: Since `count` was 1, the object is still alive.
+                    unsafe { drop_in_place(UnsafeCell::raw_get(self.revocable.data.as_ptr())) };
+                }
+
+                return;
+            }
+        }
+    }
+}
diff --git a/rust/kernel/security.rs b/rust/kernel/security.rs
new file mode 100644
index 000000000000..0a33363289d3
--- /dev/null
+++ b/rust/kernel/security.rs
@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Linux Security Modules (LSM).
+//!
+//! C header: [`include/linux/security.h`](../../../../include/linux/security.h).
+
+use crate::{bindings, cred::Credential, file::File, to_result, Result};
+
+/// Calls the security modules to determine if the given task can become the manager of a binder
+/// context.
+pub fn binder_set_context_mgr(mgr: &Credential) -> Result {
+    // SAFETY: `mrg.0` is valid because the shared reference guarantees a nonzero refcount.
+    to_result(unsafe { bindings::security_binder_set_context_mgr(mgr.0.get()) })
+}
+
+/// Calls the security modules to determine if binder transactions are allowed from task `from` to
+/// task `to`.
+pub fn binder_transaction(from: &Credential, to: &Credential) -> Result {
+    // SAFETY: `from` and `to` are valid because the shared references guarantee nonzero refcounts.
+    to_result(unsafe { bindings::security_binder_transaction(from.0.get(), to.0.get()) })
+}
+
+/// Calls the security modules to determine if task `from` is allowed to send binder objects
+/// (owned by itself or other processes) to task `to` through a binder transaction.
+pub fn binder_transfer_binder(from: &Credential, to: &Credential) -> Result {
+    // SAFETY: `from` and `to` are valid because the shared references guarantee nonzero refcounts.
+    to_result(unsafe { bindings::security_binder_transfer_binder(from.0.get(), to.0.get()) })
+}
+
+/// Calls the security modules to determine if task `from` is allowed to send the given file to
+/// task `to` (which would get its own file descriptor) through a binder transaction.
+pub fn binder_transfer_file(from: &Credential, to: &Credential, file: &File) -> Result {
+    // SAFETY: `from`, `to` and `file` are valid because the shared references guarantee nonzero
+    // refcounts.
+    to_result(unsafe {
+        bindings::security_binder_transfer_file(from.0.get(), to.0.get(), file.0.get())
+    })
+}
diff --git a/rust/kernel/static_assert.rs b/rust/kernel/static_assert.rs
new file mode 100644
index 000000000000..3115ee0ba8e9
--- /dev/null
+++ b/rust/kernel/static_assert.rs
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Static assert.
+
+/// Static assert (i.e. compile-time assert).
+///
+/// Similar to C11 [`_Static_assert`] and C++11 [`static_assert`].
+///
+/// The feature may be added to Rust in the future: see [RFC 2790].
+///
+/// [`_Static_assert`]: https://en.cppreference.com/w/c/language/_Static_assert
+/// [`static_assert`]: https://en.cppreference.com/w/cpp/language/static_assert
+/// [RFC 2790]: https://github.com/rust-lang/rfcs/issues/2790
+///
+/// # Examples
+///
+/// ```
+/// static_assert!(42 > 24);
+/// static_assert!(core::mem::size_of::<u8>() == 1);
+///
+/// const X: &[u8] = b"bar";
+/// static_assert!(X[1] == b'a');
+///
+/// const fn f(x: i32) -> i32 {
+///     x + 2
+/// }
+/// static_assert!(f(40) == 42);
+/// ```
+#[macro_export]
+macro_rules! static_assert {
+    ($condition:expr) => {
+        const _: () = core::assert!($condition);
+    };
+}
diff --git a/rust/kernel/std_vendor.rs b/rust/kernel/std_vendor.rs
new file mode 100644
index 000000000000..ffbaca0c4cb7
--- /dev/null
+++ b/rust/kernel/std_vendor.rs
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+//! The contents of this file come from the Rust standard library, hosted in
+//! the <https://github.com/rust-lang/rust> repository, licensed under
+//! "Apache-2.0 OR MIT" and adapted for kernel use. For copyright details,
+//! see <https://github.com/rust-lang/rust/blob/master/COPYRIGHT>.
+
+/// [`std::dbg`], but using [`pr_info`] instead of [`eprintln`].
+///
+/// Prints and returns the value of a given expression for quick and dirty
+/// debugging.
+///
+/// An example:
+///
+/// ```rust
+/// let a = 2;
+/// # #[allow(clippy::dbg_macro)]
+/// let b = dbg!(a * 2) + 1;
+/// //      ^-- prints: [src/main.rs:2] a * 2 = 4
+/// assert_eq!(b, 5);
+/// ```
+///
+/// The macro works by using the `Debug` implementation of the type of
+/// the given expression to print the value with [`printk`] along with the
+/// source location of the macro invocation as well as the source code
+/// of the expression.
+///
+/// Invoking the macro on an expression moves and takes ownership of it
+/// before returning the evaluated expression unchanged. If the type
+/// of the expression does not implement `Copy` and you don't want
+/// to give up ownership, you can instead borrow with `dbg!(&expr)`
+/// for some expression `expr`.
+///
+/// The `dbg!` macro works exactly the same in release builds.
+/// This is useful when debugging issues that only occur in release
+/// builds or when debugging in release mode is significantly faster.
+///
+/// Note that the macro is intended as a debugging tool and therefore you
+/// should avoid having uses of it in version control for long periods
+/// (other than in tests and similar).
+///
+/// # Stability
+///
+/// The exact output printed by this macro should not be relied upon
+/// and is subject to future changes.
+///
+/// # Further examples
+///
+/// With a method call:
+///
+/// ```rust
+/// # #[allow(clippy::dbg_macro)]
+/// fn foo(n: usize) {
+///     if dbg!(n.checked_sub(4)).is_some() {
+///         // ...
+///     }
+/// }
+///
+/// foo(3)
+/// ```
+///
+/// This prints to the kernel log:
+///
+/// ```text,ignore
+/// [src/main.rs:4] n.checked_sub(4) = None
+/// ```
+///
+/// Naive factorial implementation:
+///
+/// ```rust
+/// # #[allow(clippy::dbg_macro)]
+/// # {
+/// fn factorial(n: u32) -> u32 {
+///     if dbg!(n <= 1) {
+///         dbg!(1)
+///     } else {
+///         dbg!(n * factorial(n - 1))
+///     }
+/// }
+///
+/// dbg!(factorial(4));
+/// # }
+/// ```
+///
+/// This prints to the kernel log:
+///
+/// ```text,ignore
+/// [src/main.rs:3] n <= 1 = false
+/// [src/main.rs:3] n <= 1 = false
+/// [src/main.rs:3] n <= 1 = false
+/// [src/main.rs:3] n <= 1 = true
+/// [src/main.rs:4] 1 = 1
+/// [src/main.rs:5] n * factorial(n - 1) = 2
+/// [src/main.rs:5] n * factorial(n - 1) = 6
+/// [src/main.rs:5] n * factorial(n - 1) = 24
+/// [src/main.rs:11] factorial(4) = 24
+/// ```
+///
+/// The `dbg!(..)` macro moves the input:
+///
+// TODO: Could be `compile_fail` when supported.
+/// ```ignore
+/// /// A wrapper around `usize` which importantly is not Copyable.
+/// #[derive(Debug)]
+/// struct NoCopy(usize);
+///
+/// let a = NoCopy(42);
+/// let _ = dbg!(a); // <-- `a` is moved here.
+/// let _ = dbg!(a); // <-- `a` is moved again; error!
+/// ```
+///
+/// You can also use `dbg!()` without a value to just print the
+/// file and line whenever it's reached.
+///
+/// Finally, if you want to `dbg!(..)` multiple values, it will treat them as
+/// a tuple (and return it, too):
+///
+/// ```
+/// # #[allow(clippy::dbg_macro)]
+/// assert_eq!(dbg!(1usize, 2u32), (1, 2));
+/// ```
+///
+/// However, a single argument with a trailing comma will still not be treated
+/// as a tuple, following the convention of ignoring trailing commas in macro
+/// invocations. You can use a 1-tuple directly if you need one:
+///
+/// ```
+/// # #[allow(clippy::dbg_macro)]
+/// # {
+/// assert_eq!(1, dbg!(1u32,)); // trailing comma ignored
+/// assert_eq!((1,), dbg!((1u32,))); // 1-tuple
+/// # }
+/// ```
+///
+/// [`std::dbg`]: https://doc.rust-lang.org/std/macro.dbg.html
+/// [`eprintln`]: https://doc.rust-lang.org/std/macro.eprintln.html
+/// [`printk`]: https://www.kernel.org/doc/html/latest/core-api/printk-basics.html
+#[macro_export]
+macro_rules! dbg {
+    // NOTE: We cannot use `concat!` to make a static string as a format argument
+    // of `pr_info!` because `file!` could contain a `{` or
+    // `$val` expression could be a block (`{ .. }`), in which case the `pr_info!`
+    // will be malformed.
+    () => {
+        $crate::pr_info!("[{}:{}]\n", ::core::file!(), ::core::line!())
+    };
+    ($val:expr $(,)?) => {
+        // Use of `match` here is intentional because it affects the lifetimes
+        // of temporaries - https://stackoverflow.com/a/48732525/1063961
+        match $val {
+            tmp => {
+                $crate::pr_info!("[{}:{}] {} = {:#?}\n",
+                    ::core::file!(), ::core::line!(), ::core::stringify!($val), &tmp);
+                tmp
+            }
+        }
+    };
+    ($($val:expr),+ $(,)?) => {
+        ($($crate::dbg!($val)),+,)
+    };
+}
diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs
new file mode 100644
index 000000000000..874003e39cba
--- /dev/null
+++ b/rust/kernel/str.rs
@@ -0,0 +1,597 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! String representations.
+
+use alloc::vec::Vec;
+use core::fmt::{self, Write};
+use core::ops::{self, Deref, Index};
+
+use crate::{bindings, error::code::*, Error};
+
+/// Byte string without UTF-8 validity guarantee.
+///
+/// `BStr` is simply an alias to `[u8]`, but has a more evident semantical meaning.
+pub type BStr = [u8];
+
+/// Creates a new [`BStr`] from a string literal.
+///
+/// `b_str!` converts the supplied string literal to byte string, so non-ASCII
+/// characters can be included.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::b_str;
+/// # use kernel::str::BStr;
+/// const MY_BSTR: &BStr = b_str!("My awesome BStr!");
+/// ```
+#[macro_export]
+macro_rules! b_str {
+    ($str:literal) => {{
+        const S: &'static str = $str;
+        const C: &'static $crate::str::BStr = S.as_bytes();
+        C
+    }};
+}
+
+/// Possible errors when using conversion functions in [`CStr`].
+#[derive(Debug, Clone, Copy)]
+pub enum CStrConvertError {
+    /// Supplied bytes contain an interior `NUL`.
+    InteriorNul,
+
+    /// Supplied bytes are not terminated by `NUL`.
+    NotNulTerminated,
+}
+
+impl From<CStrConvertError> for Error {
+    #[inline]
+    fn from(_: CStrConvertError) -> Error {
+        EINVAL
+    }
+}
+
+/// A string that is guaranteed to have exactly one `NUL` byte, which is at the
+/// end.
+///
+/// Used for interoperability with kernel APIs that take C strings.
+#[repr(transparent)]
+pub struct CStr([u8]);
+
+impl CStr {
+    /// Returns the length of this string excluding `NUL`.
+    #[inline]
+    pub const fn len(&self) -> usize {
+        self.len_with_nul() - 1
+    }
+
+    /// Returns the length of this string with `NUL`.
+    #[inline]
+    pub const fn len_with_nul(&self) -> usize {
+        // SAFETY: This is one of the invariant of `CStr`.
+        // We add a `unreachable_unchecked` here to hint the optimizer that
+        // the value returned from this function is non-zero.
+        if self.0.is_empty() {
+            unsafe { core::hint::unreachable_unchecked() };
+        }
+        self.0.len()
+    }
+
+    /// Returns `true` if the string only includes `NUL`.
+    #[inline]
+    pub const fn is_empty(&self) -> bool {
+        self.len() == 0
+    }
+
+    /// Wraps a raw C string pointer.
+    ///
+    /// # Safety
+    ///
+    /// `ptr` must be a valid pointer to a `NUL`-terminated C string, and it must
+    /// last at least `'a`. When `CStr` is alive, the memory pointed by `ptr`
+    /// must not be mutated.
+    #[inline]
+    pub unsafe fn from_char_ptr<'a>(ptr: *const core::ffi::c_char) -> &'a Self {
+        // SAFETY: The safety precondition guarantees `ptr` is a valid pointer
+        // to a `NUL`-terminated C string.
+        let len = unsafe { bindings::strlen(ptr) } + 1;
+        // SAFETY: Lifetime guaranteed by the safety precondition.
+        let bytes = unsafe { core::slice::from_raw_parts(ptr as _, len as _) };
+        // SAFETY: As `len` is returned by `strlen`, `bytes` does not contain interior `NUL`.
+        // As we have added 1 to `len`, the last byte is known to be `NUL`.
+        unsafe { Self::from_bytes_with_nul_unchecked(bytes) }
+    }
+
+    /// Creates a [`CStr`] from a `[u8]`.
+    ///
+    /// The provided slice must be `NUL`-terminated, does not contain any
+    /// interior `NUL` bytes.
+    pub const fn from_bytes_with_nul(bytes: &[u8]) -> Result<&Self, CStrConvertError> {
+        if bytes.is_empty() {
+            return Err(CStrConvertError::NotNulTerminated);
+        }
+        if bytes[bytes.len() - 1] != 0 {
+            return Err(CStrConvertError::NotNulTerminated);
+        }
+        let mut i = 0;
+        // `i + 1 < bytes.len()` allows LLVM to optimize away bounds checking,
+        // while it couldn't optimize away bounds checks for `i < bytes.len() - 1`.
+        while i + 1 < bytes.len() {
+            if bytes[i] == 0 {
+                return Err(CStrConvertError::InteriorNul);
+            }
+            i += 1;
+        }
+        // SAFETY: We just checked that all properties hold.
+        Ok(unsafe { Self::from_bytes_with_nul_unchecked(bytes) })
+    }
+
+    /// Creates a [`CStr`] from a `[u8]`, panic if input is not valid.
+    ///
+    /// This function is only meant to be used by `c_str!` macro, so
+    /// crates using `c_str!` macro don't have to enable `const_panic` feature.
+    #[doc(hidden)]
+    pub const fn from_bytes_with_nul_unwrap(bytes: &[u8]) -> &Self {
+        match Self::from_bytes_with_nul(bytes) {
+            Ok(v) => v,
+            Err(_) => panic!("string contains interior NUL"),
+        }
+    }
+
+    /// Creates a [`CStr`] from a `[u8]` without performing any additional
+    /// checks.
+    ///
+    /// # Safety
+    ///
+    /// `bytes` *must* end with a `NUL` byte, and should only have a single
+    /// `NUL` byte (or the string will be truncated).
+    #[inline]
+    pub const unsafe fn from_bytes_with_nul_unchecked(bytes: &[u8]) -> &CStr {
+        // SAFETY: Properties of `bytes` guaranteed by the safety precondition.
+        unsafe { core::mem::transmute(bytes) }
+    }
+
+    /// Returns a C pointer to the string.
+    #[inline]
+    pub const fn as_char_ptr(&self) -> *const core::ffi::c_char {
+        self.0.as_ptr() as _
+    }
+
+    /// Convert the string to a byte slice without the trailing 0 byte.
+    #[inline]
+    pub fn as_bytes(&self) -> &[u8] {
+        &self.0[..self.len()]
+    }
+
+    /// Convert the string to a byte slice containing the trailing 0 byte.
+    #[inline]
+    pub const fn as_bytes_with_nul(&self) -> &[u8] {
+        &self.0
+    }
+
+    /// Yields a [`&str`] slice if the [`CStr`] contains valid UTF-8.
+    ///
+    /// If the contents of the [`CStr`] are valid UTF-8 data, this
+    /// function will return the corresponding [`&str`] slice. Otherwise,
+    /// it will return an error with details of where UTF-8 validation failed.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # use kernel::str::CStr;
+    /// let cstr = CStr::from_bytes_with_nul(b"foo\0").unwrap();
+    /// assert_eq!(cstr.to_str(), Ok("foo"));
+    /// ```
+    #[inline]
+    pub fn to_str(&self) -> Result<&str, core::str::Utf8Error> {
+        core::str::from_utf8(self.as_bytes())
+    }
+
+    /// Unsafely convert this [`CStr`] into a [`&str`], without checking for
+    /// valid UTF-8.
+    ///
+    /// # Safety
+    ///
+    /// The contents must be valid UTF-8.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// # use kernel::c_str;
+    /// # use kernel::str::CStr;
+    /// // SAFETY: String literals are guaranteed to be valid UTF-8
+    /// // by the Rust compiler.
+    /// let bar = c_str!("ツ");
+    /// assert_eq!(unsafe { bar.as_str_unchecked() }, "ツ");
+    /// ```
+    #[inline]
+    pub unsafe fn as_str_unchecked(&self) -> &str {
+        unsafe { core::str::from_utf8_unchecked(self.as_bytes()) }
+    }
+}
+
+impl fmt::Display for CStr {
+    /// Formats printable ASCII characters, escaping the rest.
+    ///
+    /// ```
+    /// # use kernel::c_str;
+    /// # use kernel::str::CStr;
+    /// # use kernel::str::CString;
+    /// let penguin = c_str!("🐧");
+    /// let s = CString::try_from_fmt(fmt!("{}", penguin)).unwrap();
+    /// assert_eq!(s.as_bytes_with_nul(), "\\xf0\\x9f\\x90\\xa7\0".as_bytes());
+    ///
+    /// let ascii = c_str!("so \"cool\"");
+    /// let s = CString::try_from_fmt(fmt!("{}", ascii)).unwrap();
+    /// assert_eq!(s.as_bytes_with_nul(), "so \"cool\"\0".as_bytes());
+    /// ```
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        for &c in self.as_bytes() {
+            if (0x20..0x7f).contains(&c) {
+                // Printable character.
+                f.write_char(c as char)?;
+            } else {
+                write!(f, "\\x{:02x}", c)?;
+            }
+        }
+        Ok(())
+    }
+}
+
+impl fmt::Debug for CStr {
+    /// Formats printable ASCII characters with a double quote on either end, escaping the rest.
+    ///
+    /// ```
+    /// # use kernel::c_str;
+    /// # use kernel::str::CStr;
+    /// # use kernel::str::CString;
+    /// let penguin = c_str!("🐧");
+    /// let s = CString::try_from_fmt(fmt!("{:?}", penguin)).unwrap();
+    /// assert_eq!(s.as_bytes_with_nul(), "\"\\xf0\\x9f\\x90\\xa7\"\0".as_bytes());
+    ///
+    /// // Embedded double quotes are escaped.
+    /// let ascii = c_str!("so \"cool\"");
+    /// let s = CString::try_from_fmt(fmt!("{:?}", ascii)).unwrap();
+    /// assert_eq!(s.as_bytes_with_nul(), "\"so \\\"cool\\\"\"\0".as_bytes());
+    /// ```
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("\"")?;
+        for &c in self.as_bytes() {
+            match c {
+                // Printable characters.
+                b'\"' => f.write_str("\\\"")?,
+                0x20..=0x7e => f.write_char(c as char)?,
+                _ => write!(f, "\\x{:02x}", c)?,
+            }
+        }
+        f.write_str("\"")
+    }
+}
+
+impl AsRef<BStr> for CStr {
+    #[inline]
+    fn as_ref(&self) -> &BStr {
+        self.as_bytes()
+    }
+}
+
+impl Deref for CStr {
+    type Target = BStr;
+
+    #[inline]
+    fn deref(&self) -> &Self::Target {
+        self.as_bytes()
+    }
+}
+
+impl Index<ops::RangeFrom<usize>> for CStr {
+    type Output = CStr;
+
+    #[inline]
+    fn index(&self, index: ops::RangeFrom<usize>) -> &Self::Output {
+        // Delegate bounds checking to slice.
+        // Assign to _ to mute clippy's unnecessary operation warning.
+        let _ = &self.as_bytes()[index.start..];
+        // SAFETY: We just checked the bounds.
+        unsafe { Self::from_bytes_with_nul_unchecked(&self.0[index.start..]) }
+    }
+}
+
+impl Index<ops::RangeFull> for CStr {
+    type Output = CStr;
+
+    #[inline]
+    fn index(&self, _index: ops::RangeFull) -> &Self::Output {
+        self
+    }
+}
+
+mod private {
+    use core::ops;
+
+    // Marker trait for index types that can be forward to `BStr`.
+    pub trait CStrIndex {}
+
+    impl CStrIndex for usize {}
+    impl CStrIndex for ops::Range<usize> {}
+    impl CStrIndex for ops::RangeInclusive<usize> {}
+    impl CStrIndex for ops::RangeToInclusive<usize> {}
+}
+
+impl<Idx> Index<Idx> for CStr
+where
+    Idx: private::CStrIndex,
+    BStr: Index<Idx>,
+{
+    type Output = <BStr as Index<Idx>>::Output;
+
+    #[inline]
+    fn index(&self, index: Idx) -> &Self::Output {
+        &self.as_bytes()[index]
+    }
+}
+
+/// Creates a new [`CStr`] from a string literal.
+///
+/// The string literal should not contain any `NUL` bytes.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::c_str;
+/// # use kernel::str::CStr;
+/// const MY_CSTR: &CStr = c_str!("My awesome CStr!");
+/// ```
+#[macro_export]
+macro_rules! c_str {
+    ($str:expr) => {{
+        const S: &str = concat!($str, "\0");
+        const C: &$crate::str::CStr = $crate::str::CStr::from_bytes_with_nul_unwrap(S.as_bytes());
+        C
+    }};
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_cstr_to_str() {
+        let good_bytes = b"\xf0\x9f\xa6\x80\0";
+        let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
+        let checked_str = checked_cstr.to_str().unwrap();
+        assert_eq!(checked_str, "🦀");
+    }
+
+    #[test]
+    #[should_panic]
+    fn test_cstr_to_str_panic() {
+        let bad_bytes = b"\xc3\x28\0";
+        let checked_cstr = CStr::from_bytes_with_nul(bad_bytes).unwrap();
+        checked_cstr.to_str().unwrap();
+    }
+
+    #[test]
+    fn test_cstr_as_str_unchecked() {
+        let good_bytes = b"\xf0\x9f\x90\xA7\0";
+        let checked_cstr = CStr::from_bytes_with_nul(good_bytes).unwrap();
+        let unchecked_str = unsafe { checked_cstr.as_str_unchecked() };
+        assert_eq!(unchecked_str, "🐧");
+    }
+}
+
+/// Allows formatting of [`fmt::Arguments`] into a raw buffer.
+///
+/// It does not fail if callers write past the end of the buffer so that they can calculate the
+/// size required to fit everything.
+///
+/// # Invariants
+///
+/// The memory region between `pos` (inclusive) and `end` (exclusive) is valid for writes if `pos`
+/// is less than `end`.
+pub(crate) struct RawFormatter {
+    // Use `usize` to use `saturating_*` functions.
+    beg: usize,
+    pos: usize,
+    end: usize,
+}
+
+impl RawFormatter {
+    /// Creates a new instance of [`RawFormatter`] with an empty buffer.
+    fn new() -> Self {
+        // INVARIANT: The buffer is empty, so the region that needs to be writable is empty.
+        Self {
+            beg: 0,
+            pos: 0,
+            end: 0,
+        }
+    }
+
+    /// Creates a new instance of [`RawFormatter`] with the given buffer pointers.
+    ///
+    /// # Safety
+    ///
+    /// If `pos` is less than `end`, then the region between `pos` (inclusive) and `end`
+    /// (exclusive) must be valid for writes for the lifetime of the returned [`RawFormatter`].
+    pub(crate) unsafe fn from_ptrs(pos: *mut u8, end: *mut u8) -> Self {
+        // INVARIANT: The safety requierments guarantee the type invariants.
+        Self {
+            beg: pos as _,
+            pos: pos as _,
+            end: end as _,
+        }
+    }
+
+    /// Creates a new instance of [`RawFormatter`] with the given buffer.
+    ///
+    /// # Safety
+    ///
+    /// The memory region starting at `buf` and extending for `len` bytes must be valid for writes
+    /// for the lifetime of the returned [`RawFormatter`].
+    pub(crate) unsafe fn from_buffer(buf: *mut u8, len: usize) -> Self {
+        let pos = buf as usize;
+        // INVARIANT: We ensure that `end` is never less then `buf`, and the safety requirements
+        // guarantees that the memory region is valid for writes.
+        Self {
+            pos,
+            beg: pos,
+            end: pos.saturating_add(len),
+        }
+    }
+
+    /// Returns the current insert position.
+    ///
+    /// N.B. It may point to invalid memory.
+    pub(crate) fn pos(&self) -> *mut u8 {
+        self.pos as _
+    }
+
+    /// Return the number of bytes written to the formatter.
+    pub(crate) fn bytes_written(&self) -> usize {
+        self.pos - self.beg
+    }
+}
+
+impl fmt::Write for RawFormatter {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        // `pos` value after writing `len` bytes. This does not have to be bounded by `end`, but we
+        // don't want it to wrap around to 0.
+        let pos_new = self.pos.saturating_add(s.len());
+
+        // Amount that we can copy. `saturating_sub` ensures we get 0 if `pos` goes past `end`.
+        let len_to_copy = core::cmp::min(pos_new, self.end).saturating_sub(self.pos);
+
+        if len_to_copy > 0 {
+            // SAFETY: If `len_to_copy` is non-zero, then we know `pos` has not gone past `end`
+            // yet, so it is valid for write per the type invariants.
+            unsafe {
+                core::ptr::copy_nonoverlapping(
+                    s.as_bytes().as_ptr(),
+                    self.pos as *mut u8,
+                    len_to_copy,
+                )
+            };
+        }
+
+        self.pos = pos_new;
+        Ok(())
+    }
+}
+
+/// Allows formatting of [`fmt::Arguments`] into a raw buffer.
+///
+/// Fails if callers attempt to write more than will fit in the buffer.
+pub(crate) struct Formatter(RawFormatter);
+
+impl Formatter {
+    /// Creates a new instance of [`Formatter`] with the given buffer.
+    ///
+    /// # Safety
+    ///
+    /// The memory region starting at `buf` and extending for `len` bytes must be valid for writes
+    /// for the lifetime of the returned [`Formatter`].
+    pub(crate) unsafe fn from_buffer(buf: *mut u8, len: usize) -> Self {
+        // SAFETY: The safety requirements of this function satisfy those of the callee.
+        Self(unsafe { RawFormatter::from_buffer(buf, len) })
+    }
+}
+
+impl Deref for Formatter {
+    type Target = RawFormatter;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl fmt::Write for Formatter {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        self.0.write_str(s)?;
+
+        // Fail the request if we go past the end of the buffer.
+        if self.0.pos > self.0.end {
+            Err(fmt::Error)
+        } else {
+            Ok(())
+        }
+    }
+}
+
+/// An owned string that is guaranteed to have exactly one `NUL` byte, which is at the end.
+///
+/// Used for interoperability with kernel APIs that take C strings.
+///
+/// # Invariants
+///
+/// The string is always `NUL`-terminated and contains no other `NUL` bytes.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::str::CString;
+///
+/// let s = CString::try_from_fmt(fmt!("{}{}{}", "abc", 10, 20)).unwrap();
+/// assert_eq!(s.as_bytes_with_nul(), "abc1020\0".as_bytes());
+///
+/// let tmp = "testing";
+/// let s = CString::try_from_fmt(fmt!("{tmp}{}", 123)).unwrap();
+/// assert_eq!(s.as_bytes_with_nul(), "testing123\0".as_bytes());
+///
+/// // This fails because it has an embedded `NUL` byte.
+/// let s = CString::try_from_fmt(fmt!("a\0b{}", 123));
+/// assert_eq!(s.is_ok(), false);
+/// ```
+pub struct CString {
+    buf: Vec<u8>,
+}
+
+impl CString {
+    /// Creates an instance of [`CString`] from the given formatted arguments.
+    pub fn try_from_fmt(args: fmt::Arguments<'_>) -> Result<Self, Error> {
+        // Calculate the size needed (formatted string plus `NUL` terminator).
+        let mut f = RawFormatter::new();
+        f.write_fmt(args)?;
+        f.write_str("\0")?;
+        let size = f.bytes_written();
+
+        // Allocate a vector with the required number of bytes, and write to it.
+        let mut buf = Vec::try_with_capacity(size)?;
+        // SAFETY: The buffer stored in `buf` is at least of size `size` and is valid for writes.
+        let mut f = unsafe { Formatter::from_buffer(buf.as_mut_ptr(), size) };
+        f.write_fmt(args)?;
+        f.write_str("\0")?;
+
+        // SAFETY: The number of bytes that can be written to `f` is bounded by `size`, which is
+        // `buf`'s capacity. The contents of the buffer have been initialised by writes to `f`.
+        unsafe { buf.set_len(f.bytes_written()) };
+
+        // Check that there are no `NUL` bytes before the end.
+        // SAFETY: The buffer is valid for read because `f.bytes_written()` is bounded by `size`
+        // (which the minimum buffer size) and is non-zero (we wrote at least the `NUL` terminator)
+        // so `f.bytes_written() - 1` doesn't underflow.
+        let ptr = unsafe { bindings::memchr(buf.as_ptr().cast(), 0, (f.bytes_written() - 1) as _) };
+        if !ptr.is_null() {
+            return Err(EINVAL);
+        }
+
+        // INVARIANT: We wrote the `NUL` terminator and checked above that no other `NUL` bytes
+        // exist in the buffer.
+        Ok(Self { buf })
+    }
+}
+
+impl Deref for CString {
+    type Target = CStr;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: The type invariants guarantee that the string is `NUL`-terminated and that no
+        // other `NUL` bytes exist.
+        unsafe { CStr::from_bytes_with_nul_unchecked(self.buf.as_slice()) }
+    }
+}
+
+/// A convenience alias for [`core::format_args`].
+#[macro_export]
+macro_rules! fmt {
+    ($($f:tt)*) => ( core::format_args!($($f)*) )
+}
diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
new file mode 100644
index 000000000000..255a4928a47a
--- /dev/null
+++ b/rust/kernel/sync.rs
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Synchronisation primitives.
+//!
+//! This module contains the kernel APIs related to synchronisation that have been ported or
+//! wrapped for usage by Rust code in the kernel and is shared by all of them.
+//!
+//! # Examples
+//!
+//! ```
+//! # use kernel::mutex_init;
+//! # use kernel::sync::Mutex;
+//! # use alloc::boxed::Box;
+//! # use core::pin::Pin;
+//! // SAFETY: `init` is called below.
+//! let mut data = Pin::from(Box::try_new(unsafe { Mutex::new(10) }).unwrap());
+//! mutex_init!(data.as_mut(), "test::data");
+//!
+//! assert_eq!(*data.lock(), 10);
+//! *data.lock() = 20;
+//! assert_eq!(*data.lock(), 20);
+//! ```
+
+use crate::{bindings, str::CStr};
+use core::{cell::UnsafeCell, mem::MaybeUninit, pin::Pin};
+
+mod arc;
+mod condvar;
+mod guard;
+mod locked_by;
+mod mutex;
+mod nowait;
+pub mod rcu;
+mod revocable;
+mod rwsem;
+mod seqlock;
+pub mod smutex;
+mod spinlock;
+
+pub use arc::{new_refcount, Ref, RefBorrow, StaticRef, UniqueRef};
+pub use condvar::CondVar;
+pub use guard::{Guard, Lock, LockFactory, LockInfo, LockIniter, ReadLock, WriteLock};
+pub use locked_by::LockedBy;
+pub use mutex::{Mutex, RevocableMutex, RevocableMutexGuard};
+pub use nowait::{NoWaitLock, NoWaitLockGuard};
+pub use revocable::{Revocable, RevocableGuard};
+pub use rwsem::{RevocableRwSemaphore, RevocableRwSemaphoreGuard, RwSemaphore};
+pub use seqlock::{SeqLock, SeqLockReadGuard};
+pub use spinlock::{RawSpinLock, SpinLock};
+
+/// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.
+#[repr(transparent)]
+pub struct LockClassKey(UnsafeCell<MaybeUninit<bindings::lock_class_key>>);
+
+// SAFETY: This is a wrapper around a lock class key, so it is safe to use references to it from
+// any thread.
+unsafe impl Sync for LockClassKey {}
+
+impl LockClassKey {
+    /// Creates a new lock class key.
+    pub const fn new() -> Self {
+        Self(UnsafeCell::new(MaybeUninit::uninit()))
+    }
+
+    pub(crate) fn get(&self) -> *mut bindings::lock_class_key {
+        self.0.get().cast()
+    }
+}
+
+/// Safely initialises an object that has an `init` function that takes a name and a lock class as
+/// arguments, examples of these are [`Mutex`] and [`SpinLock`]. Each of them also provides a more
+/// specialised name that uses this macro.
+#[doc(hidden)]
+#[macro_export]
+macro_rules! init_with_lockdep {
+    ($obj:expr, $name:expr) => {{
+        static CLASS1: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        static CLASS2: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        let obj = $obj;
+        let name = $crate::c_str!($name);
+        $crate::sync::NeedsLockClass::init(obj, name, &CLASS1, &CLASS2)
+    }};
+}
+
+/// A trait for types that need a lock class during initialisation.
+///
+/// Implementers of this trait benefit from the [`init_with_lockdep`] macro that generates a new
+/// class for each initialisation call site.
+pub trait NeedsLockClass {
+    /// Initialises the type instance so that it can be safely used.
+    ///
+    /// Callers are encouraged to use the [`init_with_lockdep`] macro as it automatically creates a
+    /// new lock class on each usage.
+    fn init(
+        self: Pin<&mut Self>,
+        name: &'static CStr,
+        key1: &'static LockClassKey,
+        key2: &'static LockClassKey,
+    );
+}
+
+/// Automatically initialises static instances of synchronisation primitives.
+///
+/// The syntax resembles that of regular static variables, except that the value assigned is that
+/// of the protected type (if one exists). In the examples below, all primitives except for
+/// [`CondVar`] require the inner value to be supplied.
+///
+/// # Examples
+///
+/// ```ignore
+/// # use kernel::{init_static_sync, sync::{CondVar, Mutex, RevocableMutex, SpinLock}};
+/// struct Test {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// init_static_sync! {
+///     static A: Mutex<Test> = Test { a: 10, b: 20 };
+///
+///     /// Documentation for `B`.
+///     pub static B: Mutex<u32> = 0;
+///
+///     pub(crate) static C: SpinLock<Test> = Test { a: 10, b: 20 };
+///     static D: CondVar;
+///
+///     static E: RevocableMutex<Test> = Test { a: 30, b: 40 };
+/// }
+/// ```
+#[macro_export]
+macro_rules! init_static_sync {
+    ($($(#[$outer:meta])* $v:vis static $id:ident : $t:ty $(= $value:expr)?;)*) => {
+        $(
+            $(#[$outer])*
+            $v static $id: $t = {
+                #[link_section = ".init_array"]
+                #[used]
+                static TMP: extern "C" fn() = {
+                    extern "C" fn constructor() {
+                        // SAFETY: This locally-defined function is only called from a constructor,
+                        // which guarantees that `$id` is not accessible from other threads
+                        // concurrently.
+                        #[allow(clippy::cast_ref_to_mut)]
+                        let mutable = unsafe { &mut *(&$id as *const _ as *mut $t) };
+                        // SAFETY: It's a shared static, so it cannot move.
+                        let pinned = unsafe { core::pin::Pin::new_unchecked(mutable) };
+                        $crate::init_with_lockdep!(pinned, stringify!($id));
+                    }
+                    constructor
+                };
+                $crate::init_static_sync!(@call_new $t, $($value)?)
+            };
+        )*
+    };
+    (@call_new $t:ty, $value:expr) => {{
+        let v = $value;
+        // SAFETY: the initialisation function is called by the constructor above.
+        unsafe { <$t>::new(v) }
+    }};
+    (@call_new $t:ty,) => {
+        // SAFETY: the initialisation function is called by the constructor above.
+        unsafe { <$t>::new() }
+    };
+}
+
+/// Reschedules the caller's task if needed.
+pub fn cond_resched() -> bool {
+    // SAFETY: No arguments, reschedules `current` if needed.
+    unsafe { bindings::cond_resched() != 0 }
+}
diff --git a/rust/kernel/sync/arc.rs b/rust/kernel/sync/arc.rs
new file mode 100644
index 000000000000..daf4aba08672
--- /dev/null
+++ b/rust/kernel/sync/arc.rs
@@ -0,0 +1,582 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A reference-counted pointer.
+//!
+//! This module implements a way for users to create reference-counted objects and pointers to
+//! them. Such a pointer automatically increments and decrements the count, and drops the
+//! underlying object when it reaches zero. It is also safe to use concurrently from multiple
+//! threads.
+//!
+//! It is different from the standard library's [`Arc`] in a few ways:
+//! 1. It is backed by the kernel's `refcount_t` type.
+//! 2. It does not support weak references, which allows it to be half the size.
+//! 3. It saturates the reference count instead of aborting when it goes over a threshold.
+//! 4. It does not provide a `get_mut` method, so the ref counted object is pinned.
+//!
+//! [`Arc`]: https://doc.rust-lang.org/std/sync/struct.Arc.html
+
+use crate::{bindings, error::code::*, Error, Opaque, Result};
+use alloc::{
+    alloc::{alloc, dealloc},
+    vec::Vec,
+};
+use core::{
+    alloc::Layout,
+    convert::{AsRef, TryFrom},
+    marker::{PhantomData, Unsize},
+    mem::{ManuallyDrop, MaybeUninit},
+    ops::{Deref, DerefMut},
+    pin::Pin,
+    ptr::{self, NonNull},
+};
+
+/// A reference-counted pointer to an instance of `T`.
+///
+/// The reference count is incremented when new instances of [`Ref`] are created, and decremented
+/// when they are dropped. When the count reaches zero, the underlying `T` is also dropped.
+///
+/// # Invariants
+///
+/// The reference count on an instance of [`Ref`] is always non-zero.
+/// The object pointed to by [`Ref`] is always pinned.
+pub struct Ref<T: ?Sized> {
+    ptr: NonNull<RefInner<T>>,
+    _p: PhantomData<RefInner<T>>,
+}
+
+#[repr(C)]
+struct RefInner<T: ?Sized> {
+    refcount: Opaque<bindings::refcount_t>,
+    data: T,
+}
+
+// This is to allow [`Ref`] (and variants) to be used as the type of `self`.
+impl<T: ?Sized> core::ops::Receiver for Ref<T> {}
+
+// This is to allow [`RefBorrow`] (and variants) to be used as the type of `self`.
+impl<T: ?Sized> core::ops::Receiver for RefBorrow<'_, T> {}
+
+// This is to allow coercion from `Ref<T>` to `Ref<U>` if `T` can be converted to the
+// dynamically-sized type (DST) `U`.
+impl<T: ?Sized + Unsize<U>, U: ?Sized> core::ops::CoerceUnsized<Ref<U>> for Ref<T> {}
+
+// This is to allow `Ref<U>` to be dispatched on when `Ref<T>` can be coerced into `Ref<U>`.
+impl<T: ?Sized + Unsize<U>, U: ?Sized> core::ops::DispatchFromDyn<Ref<U>> for Ref<T> {}
+
+// SAFETY: It is safe to send `Ref<T>` to another thread when the underlying `T` is `Sync` because
+// it effectively means sharing `&T` (which is safe because `T` is `Sync`); additionally, it needs
+// `T` to be `Send` because any thread that has a `Ref<T>` may ultimately access `T` directly, for
+// example, when the reference count reaches zero and `T` is dropped.
+unsafe impl<T: ?Sized + Sync + Send> Send for Ref<T> {}
+
+// SAFETY: It is safe to send `&Ref<T>` to another thread when the underlying `T` is `Sync` for
+// the same reason as above. `T` needs to be `Send` as well because a thread can clone a `&Ref<T>`
+// into a `Ref<T>`, which may lead to `T` being accessed by the same reasoning as above.
+unsafe impl<T: ?Sized + Sync + Send> Sync for Ref<T> {}
+
+impl<T> Ref<T> {
+    /// Constructs a new reference counted instance of `T`.
+    pub fn try_new(contents: T) -> Result<Self> {
+        let layout = Layout::new::<RefInner<T>>();
+        // SAFETY: The layout size is guaranteed to be non-zero because `RefInner` contains the
+        // reference count.
+        let inner = NonNull::new(unsafe { alloc(layout) })
+            .ok_or(ENOMEM)?
+            .cast::<RefInner<T>>();
+
+        // INVARIANT: The refcount is initialised to a non-zero value.
+        let value = RefInner {
+            refcount: Opaque::new(new_refcount()),
+            data: contents,
+        };
+        // SAFETY: `inner` is writable and properly aligned.
+        unsafe { inner.as_ptr().write(value) };
+
+        // SAFETY: We just created `inner` with a reference count of 1, which is owned by the new
+        // `Ref` object.
+        Ok(unsafe { Self::from_inner(inner) })
+    }
+
+    /// Deconstructs a [`Ref`] object into a `usize`.
+    ///
+    /// It can be reconstructed once via [`Ref::from_usize`].
+    pub fn into_usize(obj: Self) -> usize {
+        ManuallyDrop::new(obj).ptr.as_ptr() as _
+    }
+
+    /// Borrows a [`Ref`] instance previously deconstructed via [`Ref::into_usize`].
+    ///
+    /// # Safety
+    ///
+    /// `encoded` must have been returned by a previous call to [`Ref::into_usize`]. Additionally,
+    /// [`Ref::from_usize`] can only be called after *all* instances of [`RefBorrow`] have been
+    /// dropped.
+    pub unsafe fn borrow_usize<'a>(encoded: usize) -> RefBorrow<'a, T> {
+        // SAFETY: By the safety requirement of this function, we know that `encoded` came from
+        // a previous call to `Ref::into_usize`.
+        let inner = NonNull::new(encoded as *mut RefInner<T>).unwrap();
+
+        // SAFETY: The safety requirements ensure that the object remains alive for the lifetime of
+        // the returned value. There is no way to create mutable references to the object.
+        unsafe { RefBorrow::new(inner) }
+    }
+
+    /// Recreates a [`Ref`] instance previously deconstructed via [`Ref::into_usize`].
+    ///
+    /// # Safety
+    ///
+    /// `encoded` must have been returned by a previous call to [`Ref::into_usize`]. Additionally,
+    /// it can only be called once for each previous call to [`Ref::into_usize`].
+    pub unsafe fn from_usize(encoded: usize) -> Self {
+        // SAFETY: By the safety invariants we know that `encoded` came from `Ref::into_usize`, so
+        // the reference count held then will be owned by the new `Ref` object.
+        unsafe { Self::from_inner(NonNull::new(encoded as _).unwrap()) }
+    }
+}
+
+impl<T: ?Sized> Ref<T> {
+    /// Constructs a new [`Ref`] from an existing [`RefInner`].
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that `inner` points to a valid location and has a non-zero reference
+    /// count, one of which will be owned by the new [`Ref`] instance.
+    unsafe fn from_inner(inner: NonNull<RefInner<T>>) -> Self {
+        // INVARIANT: By the safety requirements, the invariants hold.
+        Ref {
+            ptr: inner,
+            _p: PhantomData,
+        }
+    }
+
+    /// Determines if two reference-counted pointers point to the same underlying instance of `T`.
+    pub fn ptr_eq(a: &Self, b: &Self) -> bool {
+        ptr::eq(a.ptr.as_ptr(), b.ptr.as_ptr())
+    }
+
+    /// Deconstructs a [`Ref`] object into a raw pointer.
+    ///
+    /// It can be reconstructed once via [`Ref::from_raw`].
+    pub fn into_raw(obj: Self) -> *const T {
+        let ret = &*obj as *const T;
+        core::mem::forget(obj);
+        ret
+    }
+
+    /// Recreates a [`Ref`] instance previously deconstructed via [`Ref::into_raw`].
+    ///
+    /// This code relies on the `repr(C)` layout of structs as described in
+    /// <https://doc.rust-lang.org/reference/type-layout.html#reprc-structs>.
+    ///
+    /// # Safety
+    ///
+    /// `ptr` must have been returned by a previous call to [`Ref::into_raw`]. Additionally, it
+    /// can only be called once for each previous call to [`Ref::into_raw`].
+    pub unsafe fn from_raw(ptr: *const T) -> Self {
+        // SAFETY: The safety requirement ensures that the pointer is valid.
+        let align = core::mem::align_of_val(unsafe { &*ptr });
+        let offset = Layout::new::<RefInner<()>>()
+            .align_to(align)
+            .unwrap()
+            .pad_to_align()
+            .size();
+        // SAFETY: The pointer is in bounds because by the safety requirements `ptr` came from
+        // `Ref::into_raw`, so it is a pointer `offset` bytes from the beginning of the allocation.
+        let data = unsafe { (ptr as *const u8).sub(offset) };
+        let metadata = ptr::metadata(ptr as *const RefInner<T>);
+        let ptr = ptr::from_raw_parts_mut(data as _, metadata);
+        // SAFETY: By the safety requirements we know that `ptr` came from `Ref::into_raw`, so the
+        // reference count held then will be owned by the new `Ref` object.
+        unsafe { Self::from_inner(NonNull::new(ptr).unwrap()) }
+    }
+
+    /// Returns a [`RefBorrow`] from the given [`Ref`].
+    ///
+    /// This is useful when the argument of a function call is a [`RefBorrow`] (e.g., in a method
+    /// receiver), but we have a [`Ref`] instead. Getting a [`RefBorrow`] is free when optimised.
+    #[inline]
+    pub fn as_ref_borrow(&self) -> RefBorrow<'_, T> {
+        // SAFETY: The constraint that lifetime of the shared reference must outlive that of
+        // the returned `RefBorrow` ensures that the object remains alive.
+        unsafe { RefBorrow::new(self.ptr) }
+    }
+}
+
+impl<T: ?Sized> Deref for Ref<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: By the type invariant, there is necessarily a reference to the object, so it is
+        // safe to dereference it.
+        unsafe { &self.ptr.as_ref().data }
+    }
+}
+
+impl<T: ?Sized> Clone for Ref<T> {
+    fn clone(&self) -> Self {
+        // INVARIANT: C `refcount_inc` saturates the refcount, so it cannot overflow to zero.
+        // SAFETY: By the type invariant, there is necessarily a reference to the object, so it is
+        // safe to increment the refcount.
+        unsafe { bindings::refcount_inc(self.ptr.as_ref().refcount.get()) };
+
+        // SAFETY: We just incremented the refcount. This increment is now owned by the new `Ref`.
+        unsafe { Self::from_inner(self.ptr) }
+    }
+}
+
+impl<T: ?Sized> AsRef<T> for Ref<T> {
+    fn as_ref(&self) -> &T {
+        // SAFETY: By the type invariant, there is necessarily a reference to the object, so it is
+        // safe to dereference it.
+        unsafe { &self.ptr.as_ref().data }
+    }
+}
+
+impl<T: ?Sized> Drop for Ref<T> {
+    fn drop(&mut self) {
+        // SAFETY: By the type invariant, there is necessarily a reference to the object. We cannot
+        // touch `refcount` after it's decremented to a non-zero value because another thread/CPU
+        // may concurrently decrement it to zero and free it. It is ok to have a raw pointer to
+        // freed/invalid memory as long as it is never dereferenced.
+        let refcount = unsafe { self.ptr.as_ref() }.refcount.get();
+
+        // INVARIANT: If the refcount reaches zero, there are no other instances of `Ref`, and
+        // this instance is being dropped, so the broken invariant is not observable.
+        // SAFETY: Also by the type invariant, we are allowed to decrement the refcount.
+        let is_zero = unsafe { bindings::refcount_dec_and_test(refcount) };
+        if is_zero {
+            // The count reached zero, we must free the memory.
+
+            // SAFETY: This thread holds the only remaining reference to `self`, so it is safe to
+            // get a mutable reference to it.
+            let inner = unsafe { self.ptr.as_mut() };
+            let layout = Layout::for_value(inner);
+            // SAFETY: The value stored in inner is valid.
+            unsafe { core::ptr::drop_in_place(inner) };
+            // SAFETY: The pointer was initialised from the result of a call to `alloc`.
+            unsafe { dealloc(self.ptr.cast().as_ptr(), layout) };
+        }
+    }
+}
+
+impl<T> TryFrom<Vec<T>> for Ref<[T]> {
+    type Error = Error;
+
+    fn try_from(mut v: Vec<T>) -> Result<Self> {
+        let value_layout = Layout::array::<T>(v.len())?;
+        let layout = Layout::new::<RefInner<()>>()
+            .extend(value_layout)?
+            .0
+            .pad_to_align();
+        // SAFETY: The layout size is guaranteed to be non-zero because `RefInner` contains the
+        // reference count.
+        let ptr = NonNull::new(unsafe { alloc(layout) }).ok_or(ENOMEM)?;
+        let inner =
+            core::ptr::slice_from_raw_parts_mut(ptr.as_ptr() as _, v.len()) as *mut RefInner<[T]>;
+
+        // SAFETY: Just an FFI call that returns a `refcount_t` initialised to 1.
+        let count = Opaque::new(unsafe { bindings::REFCOUNT_INIT(1) });
+        // SAFETY: `inner.refcount` is writable and properly aligned.
+        unsafe { core::ptr::addr_of_mut!((*inner).refcount).write(count) };
+        // SAFETY: The contents of `v` as readable and properly aligned; `inner.data` is writable
+        // and properly aligned. There is no overlap between the two because `inner` is a new
+        // allocation.
+        unsafe {
+            core::ptr::copy_nonoverlapping(
+                v.as_ptr(),
+                core::ptr::addr_of_mut!((*inner).data) as *mut [T] as *mut T,
+                v.len(),
+            )
+        };
+        // SAFETY: We're setting the new length to zero, so it is <= to capacity, and old_len..0 is
+        // an empty range (so satisfies vacuously the requirement of being initialised).
+        unsafe { v.set_len(0) };
+        // SAFETY: We just created `inner` with a reference count of 1, which is owned by the new
+        // `Ref` object.
+        Ok(unsafe { Self::from_inner(NonNull::new(inner).unwrap()) })
+    }
+}
+
+impl<T: ?Sized> From<UniqueRef<T>> for Ref<T> {
+    fn from(item: UniqueRef<T>) -> Self {
+        item.inner
+    }
+}
+
+impl<T: ?Sized> From<UniqueRef<T>> for Pin<UniqueRef<T>> {
+    fn from(obj: UniqueRef<T>) -> Self {
+        // SAFETY: It is not possible to move/replace `T` inside a `Pin<UniqueRef<T>>` (unless `T`
+        // is `Unpin`), so it is ok to convert it to `Pin<UniqueRef<T>>`.
+        unsafe { Pin::new_unchecked(obj) }
+    }
+}
+
+impl<T: ?Sized> From<Pin<UniqueRef<T>>> for Ref<T> {
+    fn from(item: Pin<UniqueRef<T>>) -> Self {
+        // SAFETY: The type invariants of `Ref` guarantee that the data is pinned.
+        unsafe { Pin::into_inner_unchecked(item).inner }
+    }
+}
+
+/// A borrowed [`Ref`] with manually-managed lifetime.
+///
+/// # Invariants
+///
+/// There are no mutable references to the underlying [`Ref`], and it remains valid for the lifetime
+/// of the [`RefBorrow`] instance.
+pub struct RefBorrow<'a, T: ?Sized + 'a> {
+    inner: NonNull<RefInner<T>>,
+    _p: PhantomData<&'a ()>,
+}
+
+impl<T: ?Sized> Clone for RefBorrow<'_, T> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<T: ?Sized> Copy for RefBorrow<'_, T> {}
+
+impl<T: ?Sized> RefBorrow<'_, T> {
+    /// Creates a new [`RefBorrow`] instance.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure the following for the lifetime of the returned [`RefBorrow`] instance:
+    /// 1. That `obj` remains valid;
+    /// 2. That no mutable references to `obj` are created.
+    unsafe fn new(inner: NonNull<RefInner<T>>) -> Self {
+        // INVARIANT: The safety requirements guarantee the invariants.
+        Self {
+            inner,
+            _p: PhantomData,
+        }
+    }
+}
+
+impl<T: ?Sized> From<RefBorrow<'_, T>> for Ref<T> {
+    fn from(b: RefBorrow<'_, T>) -> Self {
+        // SAFETY: The existence of `b` guarantees that the refcount is non-zero. `ManuallyDrop`
+        // guarantees that `drop` isn't called, so it's ok that the temporary `Ref` doesn't own the
+        // increment.
+        ManuallyDrop::new(unsafe { Ref::from_inner(b.inner) })
+            .deref()
+            .clone()
+    }
+}
+
+impl<T: ?Sized> Deref for RefBorrow<'_, T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: By the type invariant, the underlying object is still alive with no mutable
+        // references to it, so it is safe to create a shared reference.
+        unsafe { &self.inner.as_ref().data }
+    }
+}
+
+/// A refcounted object that is known to have a refcount of 1.
+///
+/// It is mutable and can be converted to a [`Ref`] so that it can be shared.
+///
+/// # Invariants
+///
+/// `inner` always has a reference count of 1.
+///
+/// # Examples
+///
+/// In the following example, we make changes to the inner object before turning it into a
+/// `Ref<Test>` object (after which point, it cannot be mutated directly). Note that `x.into()`
+/// cannot fail.
+///
+/// ```
+/// use kernel::sync::{Ref, UniqueRef};
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// fn test() -> Result<Ref<Example>> {
+///     let mut x = UniqueRef::try_new(Example { a: 10, b: 20 })?;
+///     x.a += 1;
+///     x.b += 1;
+///     Ok(x.into())
+/// }
+///
+/// # test();
+/// ```
+///
+/// In the following example we first allocate memory for a ref-counted `Example` but we don't
+/// initialise it on allocation. We do initialise it later with a call to [`UniqueRef::write`],
+/// followed by a conversion to `Ref<Example>`. This is particularly useful when allocation happens
+/// in one context (e.g., sleepable) and initialisation in another (e.g., atomic):
+///
+/// ```
+/// use kernel::sync::{Ref, UniqueRef};
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// fn test() -> Result<Ref<Example>> {
+///     let x = UniqueRef::try_new_uninit()?;
+///     Ok(x.write(Example { a: 10, b: 20 }).into())
+/// }
+///
+/// # test();
+/// ```
+///
+/// In the last example below, the caller gets a pinned instance of `Example` while converting to
+/// `Ref<Example>`; this is useful in scenarios where one needs a pinned reference during
+/// initialisation, for example, when initialising fields that are wrapped in locks.
+///
+/// ```
+/// use kernel::sync::{Ref, UniqueRef};
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// fn test() -> Result<Ref<Example>> {
+///     let mut pinned = Pin::from(UniqueRef::try_new(Example { a: 10, b: 20 })?);
+///     // We can modify `pinned` because it is `Unpin`.
+///     pinned.as_mut().a += 1;
+///     Ok(pinned.into())
+/// }
+///
+/// # test();
+/// ```
+pub struct UniqueRef<T: ?Sized> {
+    inner: Ref<T>,
+}
+
+impl<T> UniqueRef<T> {
+    /// Tries to allocate a new [`UniqueRef`] instance.
+    pub fn try_new(value: T) -> Result<Self> {
+        Ok(Self {
+            // INVARIANT: The newly-created object has a ref-count of 1.
+            inner: Ref::try_new(value)?,
+        })
+    }
+
+    /// Tries to allocate a new [`UniqueRef`] instance whose contents are not initialised yet.
+    pub fn try_new_uninit() -> Result<UniqueRef<MaybeUninit<T>>> {
+        Ok(UniqueRef::<MaybeUninit<T>> {
+            // INVARIANT: The newly-created object has a ref-count of 1.
+            inner: Ref::try_new(MaybeUninit::uninit())?,
+        })
+    }
+}
+
+impl<T> UniqueRef<MaybeUninit<T>> {
+    /// Converts a `UniqueRef<MaybeUninit<T>>` into a `UniqueRef<T>` by writing a value into it.
+    pub fn write(mut self, value: T) -> UniqueRef<T> {
+        self.deref_mut().write(value);
+        let inner = ManuallyDrop::new(self).inner.ptr;
+        UniqueRef {
+            // SAFETY: The new `Ref` is taking over `ptr` from `self.inner` (which won't be
+            // dropped). The types are compatible because `MaybeUninit<T>` is compatible with `T`.
+            inner: unsafe { Ref::from_inner(inner.cast()) },
+        }
+    }
+}
+
+impl<T: ?Sized> Deref for UniqueRef<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        self.inner.deref()
+    }
+}
+
+impl<T: ?Sized> DerefMut for UniqueRef<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        // SAFETY: By the `Ref` type invariant, there is necessarily a reference to the object, so
+        // it is safe to dereference it. Additionally, we know there is only one reference when
+        // it's inside a `UniqueRef`, so it is safe to get a mutable reference.
+        unsafe { &mut self.inner.ptr.as_mut().data }
+    }
+}
+
+/// Allows the creation of "reference-counted" globals.
+///
+/// This is achieved by biasing the refcount with +1, which ensures that the count never drops back
+/// to zero (unless buggy unsafe code incorrectly decrements without owning an increment) and
+/// therefore also ensures that `drop` is never called.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::sync::{Ref, RefBorrow, StaticRef};
+///
+/// const VALUE: u32 = 10;
+/// static SR: StaticRef<u32> = StaticRef::new(VALUE);
+///
+/// fn takes_ref_borrow(v: RefBorrow<'_, u32>) {
+///     assert_eq!(*v, VALUE);
+/// }
+///
+/// fn takes_ref(v: Ref<u32>) {
+///     assert_eq!(*v, VALUE);
+/// }
+///
+/// takes_ref_borrow(SR.as_ref_borrow());
+/// takes_ref(SR.as_ref_borrow().into());
+/// ```
+pub struct StaticRef<T: ?Sized> {
+    inner: RefInner<T>,
+}
+
+// SAFETY: A `StaticRef<T>` is a `Ref<T>` declared statically, so we just use the same criteria for
+// making it `Sync`.
+unsafe impl<T: ?Sized + Sync + Send> Sync for StaticRef<T> {}
+
+impl<T> StaticRef<T> {
+    /// Creates a new instance of a static "ref-counted" object.
+    pub const fn new(data: T) -> Self {
+        // INVARIANT: The refcount is initialised to a non-zero value.
+        Self {
+            inner: RefInner {
+                refcount: Opaque::new(new_refcount()),
+                data,
+            },
+        }
+    }
+}
+
+impl<T: ?Sized> StaticRef<T> {
+    /// Creates a [`RefBorrow`] instance from the given static object.
+    ///
+    /// This requires a `'static` lifetime so that it can guarantee that the underlyling object
+    /// remains valid and is effectively pinned.
+    pub fn as_ref_borrow(&'static self) -> RefBorrow<'static, T> {
+        // SAFETY: The static lifetime guarantees that the object remains valid. And the shared
+        // reference guarantees that no mutable references exist.
+        unsafe { RefBorrow::new(NonNull::from(&self.inner)) }
+    }
+}
+
+/// Creates, from a const context, a new instance of `struct refcount_struct` with a refcount of 1.
+///
+/// ```
+/// # // The test below is meant to ensure that `new_refcount` (which is const) mimics
+/// # // `REFCOUNT_INIT`, which is written in C and thus can't be used in a const context.
+/// # // TODO: Once `#[test]` is working, move this to a test and make `new_refcount` private.
+/// # use kernel::bindings;
+/// # // SAFETY: Just an FFI call that returns a `refcount_t` initialised to 1.
+/// # let bindings::refcount_struct {
+/// #     refs: bindings::atomic_t { counter: a },
+/// # } = unsafe { bindings::REFCOUNT_INIT(1) };
+/// # let bindings::refcount_struct {
+/// #     refs: bindings::atomic_t { counter: b },
+/// # } = kernel::sync::new_refcount();
+/// # assert_eq!(a, b);
+/// ```
+pub const fn new_refcount() -> bindings::refcount_struct {
+    bindings::refcount_struct {
+        refs: bindings::atomic_t { counter: 1 },
+    }
+}
diff --git a/rust/kernel/sync/condvar.rs b/rust/kernel/sync/condvar.rs
new file mode 100644
index 000000000000..b6102906fb3c
--- /dev/null
+++ b/rust/kernel/sync/condvar.rs
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A condition variable.
+//!
+//! This module allows Rust code to use the kernel's [`struct wait_queue_head`] as a condition
+//! variable.
+
+use super::{Guard, Lock, LockClassKey, LockInfo, NeedsLockClass};
+use crate::{bindings, str::CStr, task::Task, Opaque};
+use core::{marker::PhantomPinned, pin::Pin};
+
+/// Safely initialises a [`CondVar`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! condvar_init {
+    ($condvar:expr, $name:literal) => {
+        $crate::init_with_lockdep!($condvar, $name)
+    };
+}
+
+// TODO: `bindgen` is not generating this constant. Figure out why.
+const POLLFREE: u32 = 0x4000;
+
+/// Exposes the kernel's [`struct wait_queue_head`] as a condition variable. It allows the caller to
+/// atomically release the given lock and go to sleep. It reacquires the lock when it wakes up. And
+/// it wakes up when notified by another thread (via [`CondVar::notify_one`] or
+/// [`CondVar::notify_all`]) or because the thread received a signal.
+///
+/// [`struct wait_queue_head`]: ../../../include/linux/wait.h
+pub struct CondVar {
+    pub(crate) wait_list: Opaque<bindings::wait_queue_head>,
+
+    /// A condvar needs to be pinned because it contains a [`struct list_head`] that is
+    /// self-referential, so it cannot be safely moved once it is initialised.
+    _pin: PhantomPinned,
+}
+
+// SAFETY: `CondVar` only uses a `struct wait_queue_head`, which is safe to use on any thread.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl Send for CondVar {}
+
+// SAFETY: `CondVar` only uses a `struct wait_queue_head`, which is safe to use on multiple threads
+// concurrently.
+unsafe impl Sync for CondVar {}
+
+impl CondVar {
+    /// Constructs a new conditional variable.
+    ///
+    /// # Safety
+    ///
+    /// The caller must call `CondVar::init` before using the conditional variable.
+    pub const unsafe fn new() -> Self {
+        Self {
+            wait_list: Opaque::uninit(),
+            _pin: PhantomPinned,
+        }
+    }
+
+    /// Atomically releases the given lock (whose ownership is proven by the guard) and puts the
+    /// thread to sleep. It wakes up when notified by [`CondVar::notify_one`] or
+    /// [`CondVar::notify_all`], or when the thread receives a signal.
+    ///
+    /// Returns whether there is a signal pending.
+    #[must_use = "wait returns if a signal is pending, so the caller must check the return value"]
+    pub fn wait<L: Lock<I>, I: LockInfo>(&self, guard: &mut Guard<'_, L, I>) -> bool {
+        let lock = guard.lock;
+        let wait = Opaque::<bindings::wait_queue_entry>::uninit();
+
+        // SAFETY: `wait` points to valid memory.
+        unsafe { bindings::init_wait(wait.get()) };
+
+        // SAFETY: Both `wait` and `wait_list` point to valid memory.
+        unsafe {
+            bindings::prepare_to_wait_exclusive(
+                self.wait_list.get(),
+                wait.get(),
+                bindings::TASK_INTERRUPTIBLE as _,
+            )
+        };
+
+        // SAFETY: The guard is evidence that the caller owns the lock.
+        unsafe { lock.unlock(&mut guard.context) };
+
+        // SAFETY: No arguments, switches to another thread.
+        unsafe { bindings::schedule() };
+
+        guard.context = lock.lock_noguard();
+
+        // SAFETY: Both `wait` and `wait_list` point to valid memory.
+        unsafe { bindings::finish_wait(self.wait_list.get(), wait.get()) };
+
+        Task::current().signal_pending()
+    }
+
+    /// Calls the kernel function to notify the appropriate number of threads with the given flags.
+    fn notify(&self, count: i32, flags: u32) {
+        // SAFETY: `wait_list` points to valid memory.
+        unsafe {
+            bindings::__wake_up(
+                self.wait_list.get(),
+                bindings::TASK_NORMAL,
+                count,
+                flags as _,
+            )
+        };
+    }
+
+    /// Wakes a single waiter up, if any. This is not 'sticky' in the sense that if no thread is
+    /// waiting, the notification is lost completely (as opposed to automatically waking up the
+    /// next waiter).
+    pub fn notify_one(&self) {
+        self.notify(1, 0);
+    }
+
+    /// Wakes all waiters up, if any. This is not 'sticky' in the sense that if no thread is
+    /// waiting, the notification is lost completely (as opposed to automatically waking up the
+    /// next waiter).
+    pub fn notify_all(&self) {
+        self.notify(0, 0);
+    }
+
+    /// Wakes all waiters up. If they were added by `epoll`, they are also removed from the list of
+    /// waiters. This is useful when cleaning up a condition variable that may be waited on by
+    /// threads that use `epoll`.
+    pub fn free_waiters(&self) {
+        self.notify(1, bindings::POLLHUP | POLLFREE);
+    }
+}
+
+impl NeedsLockClass for CondVar {
+    fn init(
+        self: Pin<&mut Self>,
+        name: &'static CStr,
+        key: &'static LockClassKey,
+        _: &'static LockClassKey,
+    ) {
+        unsafe {
+            bindings::__init_waitqueue_head(self.wait_list.get(), name.as_char_ptr(), key.get())
+        };
+    }
+}
diff --git a/rust/kernel/sync/guard.rs b/rust/kernel/sync/guard.rs
new file mode 100644
index 000000000000..757d85eac7af
--- /dev/null
+++ b/rust/kernel/sync/guard.rs
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A generic lock guard and trait.
+//!
+//! This module contains a lock guard that can be used with any locking primitive that implements
+//! the ([`Lock`]) trait. It also contains the definition of the trait, which can be leveraged by
+//! other constructs to work on generic locking primitives.
+
+use super::{LockClassKey, NeedsLockClass};
+use crate::{str::CStr, Bool, False, True};
+use core::pin::Pin;
+
+/// Allows mutual exclusion primitives that implement the [`Lock`] trait to automatically unlock
+/// when a guard goes out of scope. It also provides a safe and convenient way to access the data
+/// protected by the lock.
+#[must_use = "the lock unlocks immediately when the guard is unused"]
+pub struct Guard<'a, L: Lock<I> + ?Sized, I: LockInfo = WriteLock> {
+    pub(crate) lock: &'a L,
+    pub(crate) context: L::GuardContext,
+}
+
+// SAFETY: `Guard` is sync when the data protected by the lock is also sync. This is more
+// conservative than the default compiler implementation; more details can be found on
+// <https://github.com/rust-lang/rust/issues/41622> -- it refers to `MutexGuard` from the standard
+// library.
+unsafe impl<L, I> Sync for Guard<'_, L, I>
+where
+    L: Lock<I> + ?Sized,
+    L::Inner: Sync,
+    I: LockInfo,
+{
+}
+
+impl<L: Lock<I> + ?Sized, I: LockInfo> core::ops::Deref for Guard<'_, L, I> {
+    type Target = L::Inner;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: The caller owns the lock, so it is safe to deref the protected data.
+        unsafe { &*self.lock.locked_data().get() }
+    }
+}
+
+impl<L: Lock<I> + ?Sized, I: LockInfo<Writable = True>> core::ops::DerefMut for Guard<'_, L, I> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        // SAFETY: The caller owns the lock, so it is safe to deref the protected data.
+        unsafe { &mut *self.lock.locked_data().get() }
+    }
+}
+
+impl<L: Lock<I> + ?Sized, I: LockInfo> Drop for Guard<'_, L, I> {
+    fn drop(&mut self) {
+        // SAFETY: The caller owns the lock, so it is safe to unlock it.
+        unsafe { self.lock.unlock(&mut self.context) };
+    }
+}
+
+impl<'a, L: Lock<I> + ?Sized, I: LockInfo> Guard<'a, L, I> {
+    /// Constructs a new immutable lock guard.
+    ///
+    /// # Safety
+    ///
+    /// The caller must ensure that it owns the lock.
+    pub(crate) unsafe fn new(lock: &'a L, context: L::GuardContext) -> Self {
+        Self { lock, context }
+    }
+}
+
+/// Specifies properties of a lock.
+pub trait LockInfo {
+    /// Determines if the data protected by a lock is writable.
+    type Writable: Bool;
+}
+
+/// A marker for locks that only allow reading.
+pub struct ReadLock;
+impl LockInfo for ReadLock {
+    type Writable = False;
+}
+
+/// A marker for locks that allow reading and writing.
+pub struct WriteLock;
+impl LockInfo for WriteLock {
+    type Writable = True;
+}
+
+/// A generic mutual exclusion primitive.
+///
+/// [`Guard`] is written such that any mutual exclusion primitive that can implement this trait can
+/// also benefit from having an automatic way to unlock itself.
+///
+/// # Safety
+///
+/// - Implementers of this trait with the [`WriteLock`] marker must ensure that only one thread/CPU
+///   may access the protected data once the lock is held, that is, between calls to `lock_noguard`
+///   and `unlock`.
+/// - Implementers of all other markers must ensure that a mutable reference to the protected data
+///   is not active in any thread/CPU because at least one shared reference is active between calls
+///   to `lock_noguard` and `unlock`.
+pub unsafe trait Lock<I: LockInfo = WriteLock> {
+    /// The type of the data protected by the lock.
+    type Inner: ?Sized;
+
+    /// The type of context, if any, that needs to be stored in the guard.
+    type GuardContext;
+
+    /// Acquires the lock, making the caller its owner.
+    #[must_use]
+    fn lock_noguard(&self) -> Self::GuardContext;
+
+    /// Reacquires the lock, making the caller its owner.
+    ///
+    /// The guard context before the last unlock is passed in.
+    ///
+    /// Locks that don't require this state on relock can simply use the default implementation
+    /// that calls [`Lock::lock_noguard`].
+    fn relock(&self, ctx: &mut Self::GuardContext) {
+        *ctx = self.lock_noguard();
+    }
+
+    /// Releases the lock, giving up ownership of the lock.
+    ///
+    /// # Safety
+    ///
+    /// It must only be called by the current owner of the lock.
+    unsafe fn unlock(&self, context: &mut Self::GuardContext);
+
+    /// Returns the data protected by the lock.
+    fn locked_data(&self) -> &core::cell::UnsafeCell<Self::Inner>;
+}
+
+/// A creator of instances of a mutual exclusion (lock) primitive.
+pub trait LockFactory {
+    /// The parametrised type of the mutual exclusion primitive that can be created by this factory.
+    type LockedType<T>;
+
+    /// Constructs a new instance of the mutual exclusion primitive.
+    ///
+    /// # Safety
+    ///
+    /// The caller must call [`LockIniter::init_lock`] before using the lock.
+    unsafe fn new_lock<T>(data: T) -> Self::LockedType<T>;
+}
+
+/// A lock that can be initialised with a single lock class key.
+pub trait LockIniter {
+    /// Initialises the lock instance so that it can be safely used.
+    fn init_lock(self: Pin<&mut Self>, name: &'static CStr, key: &'static LockClassKey);
+}
+
+impl<L: LockIniter> NeedsLockClass for L {
+    fn init(
+        self: Pin<&mut Self>,
+        name: &'static CStr,
+        key: &'static LockClassKey,
+        _: &'static LockClassKey,
+    ) {
+        self.init_lock(name, key);
+    }
+}
diff --git a/rust/kernel/sync/locked_by.rs b/rust/kernel/sync/locked_by.rs
new file mode 100644
index 000000000000..2dc6e3a77420
--- /dev/null
+++ b/rust/kernel/sync/locked_by.rs
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A wrapper for data protected by a lock that does not wrap it.
+
+use super::{Guard, Lock};
+use core::{cell::UnsafeCell, ops::Deref, ptr};
+
+/// Allows access to some data to be serialised by a lock that does not wrap it.
+///
+/// In most cases, data protected by a lock is wrapped by the appropriate lock type, e.g.,
+/// [`super::Mutex`] or [`super::SpinLock`]. [`LockedBy`] is meant for cases when this is not
+/// possible. For example, if a container has a lock and some data in the contained elements needs
+/// to be protected by the same lock.
+///
+/// [`LockedBy`] wraps the data in lieu of another locking primitive, and only allows access to it
+/// when the caller shows evidence that 'external' lock is locked.
+///
+/// # Examples
+///
+/// The following is an example for illustrative purposes: `InnerDirectory::bytes_used` is an
+/// aggregate of all `InnerFile::bytes_used` and must be kept consistent; so we wrap `InnerFile` in
+/// a `LockedBy` so that it shares a lock with `InnerDirectory`. This allows us to enforce at
+/// compile-time that access to `InnerFile` is only granted when an `InnerDirectory` is also
+/// locked; we enforce at run time that the right `InnerDirectory` is locked.
+///
+/// ```
+/// use kernel::sync::{LockedBy, Mutex};
+///
+/// struct InnerFile {
+///     bytes_used: u64,
+/// }
+///
+/// struct File {
+///     name: String,
+///     inner: LockedBy<InnerFile, Mutex<InnerDirectory>>,
+/// }
+///
+/// struct InnerDirectory {
+///     /// The sum of the bytes used by all files.
+///     bytes_used: u64,
+///     files: Vec<File>,
+/// }
+///
+/// struct Directory {
+///     name: String,
+///     inner: Mutex<InnerDirectory>,
+/// }
+/// ```
+pub struct LockedBy<T: ?Sized, L: Lock + ?Sized> {
+    owner: *const L::Inner,
+    data: UnsafeCell<T>,
+}
+
+// SAFETY: `LockedBy` can be transferred across thread boundaries iff the data it protects can.
+unsafe impl<T: ?Sized + Send, L: Lock + ?Sized> Send for LockedBy<T, L> {}
+
+// SAFETY: `LockedBy` serialises the interior mutability it provides, so it is `Sync` as long as the
+// data it protects is `Send`.
+unsafe impl<T: ?Sized + Send, L: Lock + ?Sized> Sync for LockedBy<T, L> {}
+
+impl<T, L: Lock + ?Sized> LockedBy<T, L> {
+    /// Constructs a new instance of [`LockedBy`].
+    ///
+    /// It stores a raw pointer to the owner that is never dereferenced. It is only used to ensure
+    /// that the right owner is being used to access the protected data. If the owner is freed, the
+    /// data becomes inaccessible; if another instance of the owner is allocated *on the same
+    /// memory location*, the data becomes accessible again: none of this affects memory safety
+    /// because in any case at most one thread (or CPU) can access the protected data at a time.
+    pub fn new(owner: &L, data: T) -> Self {
+        Self {
+            owner: owner.locked_data().get(),
+            data: UnsafeCell::new(data),
+        }
+    }
+}
+
+impl<T: ?Sized, L: Lock + ?Sized> LockedBy<T, L> {
+    /// Returns a reference to the protected data when the caller provides evidence (via a
+    /// [`Guard`]) that the owner is locked.
+    pub fn access<'a>(&'a self, guard: &'a Guard<'_, L>) -> &'a T {
+        if !ptr::eq(guard.deref(), self.owner) {
+            panic!("guard does not match owner");
+        }
+
+        // SAFETY: `guard` is evidence that the owner is locked.
+        unsafe { &mut *self.data.get() }
+    }
+
+    /// Returns a mutable reference to the protected data when the caller provides evidence (via a
+    /// mutable [`Guard`]) that the owner is locked mutably.
+    pub fn access_mut<'a>(&'a self, guard: &'a mut Guard<'_, L>) -> &'a mut T {
+        if !ptr::eq(guard.deref().deref(), self.owner) {
+            panic!("guard does not match owner");
+        }
+
+        // SAFETY: `guard` is evidence that the owner is locked.
+        unsafe { &mut *self.data.get() }
+    }
+
+    /// Returns a mutable reference to the protected data when the caller provides evidence (via a
+    /// mutable owner) that the owner is locked mutably. Showing a mutable reference to the owner
+    /// is sufficient because we know no other references can exist to it.
+    pub fn access_from_mut<'a>(&'a self, owner: &'a mut L::Inner) -> &'a mut T {
+        if !ptr::eq(owner, self.owner) {
+            panic!("mismatched owners");
+        }
+
+        // SAFETY: `owner` is evidence that there is only one reference to the owner.
+        unsafe { &mut *self.data.get() }
+    }
+}
diff --git a/rust/kernel/sync/mutex.rs b/rust/kernel/sync/mutex.rs
new file mode 100644
index 000000000000..c51ae5e3a8a0
--- /dev/null
+++ b/rust/kernel/sync/mutex.rs
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A kernel mutex.
+//!
+//! This module allows Rust code to use the kernel's [`struct mutex`].
+
+use super::{Guard, Lock, LockClassKey, LockFactory, LockIniter, WriteLock};
+use crate::{bindings, str::CStr, Opaque};
+use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin};
+
+/// Safely initialises a [`Mutex`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! mutex_init {
+    ($mutex:expr, $name:literal) => {
+        $crate::init_with_lockdep!($mutex, $name)
+    };
+}
+
+/// Exposes the kernel's [`struct mutex`]. When multiple threads attempt to lock the same mutex,
+/// only one at a time is allowed to progress, the others will block (sleep) until the mutex is
+/// unlocked, at which point another thread will be allowed to wake up and make progress.
+///
+/// A [`Mutex`] must first be initialised with a call to [`Mutex::init_lock`] before it can be
+/// used. The [`mutex_init`] macro is provided to automatically assign a new lock class to a mutex
+/// instance.
+///
+/// Since it may block, [`Mutex`] needs to be used with care in atomic contexts.
+///
+/// [`struct mutex`]: ../../../include/linux/mutex.h
+pub struct Mutex<T: ?Sized> {
+    /// The kernel `struct mutex` object.
+    mutex: Opaque<bindings::mutex>,
+
+    /// A mutex needs to be pinned because it contains a [`struct list_head`] that is
+    /// self-referential, so it cannot be safely moved once it is initialised.
+    _pin: PhantomPinned,
+
+    /// The data protected by the mutex.
+    data: UnsafeCell<T>,
+}
+
+// SAFETY: `Mutex` can be transferred across thread boundaries iff the data it protects can.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: ?Sized + Send> Send for Mutex<T> {}
+
+// SAFETY: `Mutex` serialises the interior mutability it provides, so it is `Sync` as long as the
+// data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {}
+
+impl<T> Mutex<T> {
+    /// Constructs a new mutex.
+    ///
+    /// # Safety
+    ///
+    /// The caller must call [`Mutex::init_lock`] before using the mutex.
+    pub const unsafe fn new(t: T) -> Self {
+        Self {
+            mutex: Opaque::uninit(),
+            data: UnsafeCell::new(t),
+            _pin: PhantomPinned,
+        }
+    }
+}
+
+impl<T: ?Sized> Mutex<T> {
+    /// Locks the mutex and gives the caller access to the data protected by it. Only one thread at
+    /// a time is allowed to access the protected data.
+    pub fn lock(&self) -> Guard<'_, Self> {
+        let ctx = self.lock_noguard();
+        // SAFETY: The mutex was just acquired.
+        unsafe { Guard::new(self, ctx) }
+    }
+}
+
+impl<T> LockFactory for Mutex<T> {
+    type LockedType<U> = Mutex<U>;
+
+    unsafe fn new_lock<U>(data: U) -> Mutex<U> {
+        // SAFETY: The safety requirements of `new_lock` also require that `init_lock` be called.
+        unsafe { Mutex::new(data) }
+    }
+}
+
+impl<T> LockIniter for Mutex<T> {
+    fn init_lock(self: Pin<&mut Self>, name: &'static CStr, key: &'static LockClassKey) {
+        unsafe { bindings::__mutex_init(self.mutex.get(), name.as_char_ptr(), key.get()) };
+    }
+}
+
+pub struct EmptyGuardContext;
+
+// SAFETY: The underlying kernel `struct mutex` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock for Mutex<T> {
+    type Inner = T;
+    type GuardContext = EmptyGuardContext;
+
+    fn lock_noguard(&self) -> EmptyGuardContext {
+        // SAFETY: `mutex` points to valid memory.
+        unsafe { bindings::mutex_lock(self.mutex.get()) };
+        EmptyGuardContext
+    }
+
+    unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+        // SAFETY: The safety requirements of the function ensure that the mutex is owned by the
+        // caller.
+        unsafe { bindings::mutex_unlock(self.mutex.get()) };
+    }
+
+    fn locked_data(&self) -> &UnsafeCell<T> {
+        &self.data
+    }
+}
+
+/// A revocable mutex.
+///
+/// That is, a mutex to which access can be revoked at runtime. It is a specialisation of the more
+/// generic [`super::revocable::Revocable`].
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::RevocableMutex;
+/// # use kernel::revocable_init;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// fn read_sum(v: &RevocableMutex<Example>) -> Option<u32> {
+///     let guard = v.try_write()?;
+///     Some(guard.a + guard.b)
+/// }
+///
+/// // SAFETY: We call `revocable_init` immediately below.
+/// let mut v = unsafe { RevocableMutex::new(Example { a: 10, b: 20 }) };
+/// // SAFETY: We never move out of `v`.
+/// let pinned = unsafe { Pin::new_unchecked(&mut v) };
+/// revocable_init!(pinned, "example::v");
+/// assert_eq!(read_sum(&v), Some(30));
+/// v.revoke();
+/// assert_eq!(read_sum(&v), None);
+/// ```
+pub type RevocableMutex<T> = super::revocable::Revocable<Mutex<()>, T>;
+
+/// A guard for a revocable mutex.
+pub type RevocableMutexGuard<'a, T, I = WriteLock> =
+    super::revocable::RevocableGuard<'a, Mutex<()>, T, I>;
diff --git a/rust/kernel/sync/nowait.rs b/rust/kernel/sync/nowait.rs
new file mode 100644
index 000000000000..09852d71aeb2
--- /dev/null
+++ b/rust/kernel/sync/nowait.rs
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A lock that never waits.
+
+use core::cell::UnsafeCell;
+use core::sync::atomic::{AtomicU8, Ordering};
+
+const LOCKED: u8 = 1;
+const CONTENDED: u8 = 2;
+
+/// A lock that only offers a [`try_lock`](NoWaitLock::try_lock) method.
+///
+/// That is, on contention it doesn't offer a way for the caller to block waiting for the current
+/// owner to release the lock. This is useful for best-effort kind of scenarios where waiting is
+/// never needed: in such cases, users don't need a full-featured mutex or spinlock.
+///
+/// When the lock is released via call to [`NoWaitLockGuard::unlock`], it indicates to the caller
+/// whether there was contention (i.e., if another thread tried and failed to acquire this lock).
+/// If the return value is `false`, there was definitely no contention but if it is `true`, it's
+/// possible that the contention was when attempting to acquire the lock.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::sync::NoWaitLock;
+///
+/// #[derive(PartialEq)]
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// let x = NoWaitLock::new(Example { a: 10, b: 20 });
+///
+/// // Modifying the protected value.
+/// {
+///     let mut guard = x.try_lock().unwrap();
+///     assert_eq!(guard.a, 10);
+///     assert_eq!(guard.b, 20);
+///     guard.a += 20;
+///     guard.b += 20;
+///     assert_eq!(guard.a, 30);
+///     assert_eq!(guard.b, 40);
+/// }
+///
+/// // Reading the protected value.
+/// {
+///     let guard = x.try_lock().unwrap();
+///     assert_eq!(guard.a, 30);
+///     assert_eq!(guard.b, 40);
+/// }
+///
+/// // Second acquire fails, but succeeds after the guard is dropped.
+/// {
+///     let guard = x.try_lock().unwrap();
+///     assert!(x.try_lock().is_none());
+///
+///     drop(guard);
+///     assert!(x.try_lock().is_some());
+/// }
+/// ```
+///
+/// The following examples use the [`NoWaitLockGuard::unlock`] to release the lock and check for
+/// contention.
+///
+/// ```
+/// use kernel::sync::NoWaitLock;
+///
+/// #[derive(PartialEq)]
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// let x = NoWaitLock::new(Example { a: 10, b: 20 });
+///
+/// // No contention when lock is released.
+/// let guard = x.try_lock().unwrap();
+/// assert_eq!(guard.unlock(), false);
+///
+/// // Contention detected.
+/// let guard = x.try_lock().unwrap();
+/// assert!(x.try_lock().is_none());
+/// assert_eq!(guard.unlock(), true);
+///
+/// // No contention again.
+/// let guard = x.try_lock().unwrap();
+/// assert_eq!(guard.a, 10);
+/// assert_eq!(guard.b, 20);
+/// assert_eq!(guard.unlock(), false);
+/// ```
+pub struct NoWaitLock<T: ?Sized> {
+    state: AtomicU8,
+    data: UnsafeCell<T>,
+}
+
+// SAFETY: `NoWaitLock` can be transferred across thread boundaries iff the data it protects can.
+unsafe impl<T: ?Sized + Send> Send for NoWaitLock<T> {}
+
+// SAFETY: `NoWaitLock` only allows a single thread at a time to access the interior mutability it
+// provides, so it is `Sync` as long as the data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for NoWaitLock<T> {}
+
+impl<T> NoWaitLock<T> {
+    /// Creates a new instance of the no-wait lock.
+    pub fn new(data: T) -> Self {
+        Self {
+            state: AtomicU8::new(0),
+            data: UnsafeCell::new(data),
+        }
+    }
+}
+
+impl<T: ?Sized> NoWaitLock<T> {
+    /// Tries to acquire the lock.
+    ///
+    /// If no other thread/CPU currently owns the lock, it returns a guard that can be used to
+    /// access the protected data. Otherwise (i.e., the lock is already owned), it returns `None`.
+    pub fn try_lock(&self) -> Option<NoWaitLockGuard<'_, T>> {
+        // Fast path -- just set the LOCKED bit.
+        //
+        // Acquire ordering matches the release in `NoWaitLockGuard::drop` or
+        // `NoWaitLockGuard::unlock`.
+        if self.state.fetch_or(LOCKED, Ordering::Acquire) & LOCKED == 0 {
+            // INVARIANTS: The thread that manages to set the `LOCKED` bit becomes the owner.
+            return Some(NoWaitLockGuard { lock: self });
+        }
+
+        // Set the `CONTENDED` bit.
+        //
+        // If the `LOCKED` bit has since been reset, the lock was released and the caller becomes
+        // the owner of the lock. It will see the `CONTENDED` bit when it releases the lock even if
+        // there was no additional contention but this is allowed by the interface.
+        if self.state.fetch_or(CONTENDED | LOCKED, Ordering::Relaxed) & LOCKED == 0 {
+            // INVARIANTS: The thread that manages to set the `LOCKED` bit becomes the owner.
+            Some(NoWaitLockGuard { lock: self })
+        } else {
+            None
+        }
+    }
+}
+
+/// A guard for the holder of the no-wait lock.
+///
+/// # Invariants
+///
+/// Only the current owner can have an instance of [`NoWaitLockGuard`].
+pub struct NoWaitLockGuard<'a, T: ?Sized> {
+    lock: &'a NoWaitLock<T>,
+}
+
+impl<T: ?Sized> NoWaitLockGuard<'_, T> {
+    /// Unlocks the no-wait lock.
+    ///
+    /// The return value indicates whether there was contention while the lock was held, that is,
+    /// whether another thread tried (and failed) to acquire the lock.
+    pub fn unlock(self) -> bool {
+        // Matches the acquire in `NoWaitLock::try_lock`.
+        let contention = self.lock.state.swap(0, Ordering::Release) & CONTENDED != 0;
+        core::mem::forget(self);
+        contention
+    }
+}
+
+impl<T: ?Sized> core::ops::Deref for NoWaitLockGuard<'_, T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: The type invariant guarantees that only the owner has an instance of the guard,
+        // so the owner is the only one that can call this function.
+        unsafe { &*self.lock.data.get() }
+    }
+}
+
+impl<T: ?Sized> core::ops::DerefMut for NoWaitLockGuard<'_, T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        // SAFETY: The type invariant guarantees that only the owner has an instance of the guard,
+        // so the owner is the only one that can call this function.
+        unsafe { &mut *self.lock.data.get() }
+    }
+}
+
+impl<T: ?Sized> Drop for NoWaitLockGuard<'_, T> {
+    fn drop(&mut self) {
+        // Matches the acquire in `NoWaitLock::try_lock`.
+        self.lock.state.store(0, Ordering::Release);
+    }
+}
diff --git a/rust/kernel/sync/rcu.rs b/rust/kernel/sync/rcu.rs
new file mode 100644
index 000000000000..1a1c8ea49359
--- /dev/null
+++ b/rust/kernel/sync/rcu.rs
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! RCU support.
+//!
+//! C header: [`include/linux/rcupdate.h`](../../../../include/linux/rcupdate.h)
+
+use crate::bindings;
+use core::marker::PhantomData;
+
+/// Evidence that the RCU read side lock is held on the current thread/CPU.
+///
+/// The type is explicitly not `Send` because this property is per-thread/CPU.
+///
+/// # Invariants
+///
+/// The RCU read side lock is actually held while instances of this guard exist.
+pub struct Guard {
+    _not_send: PhantomData<*mut ()>,
+}
+
+impl Guard {
+    /// Acquires the RCU read side lock and returns a guard.
+    pub fn new() -> Self {
+        // SAFETY: An FFI call with no additional requirements.
+        unsafe { bindings::rcu_read_lock() };
+        // INVARIANT: The RCU read side lock was just acquired above.
+        Self {
+            _not_send: PhantomData,
+        }
+    }
+
+    /// Explicitly releases the RCU read side lock.
+    pub fn unlock(self) {}
+}
+
+impl Default for Guard {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Drop for Guard {
+    fn drop(&mut self) {
+        // SAFETY: By the type invariants, the rcu read side is locked, so it is ok to unlock it.
+        unsafe { bindings::rcu_read_unlock() };
+    }
+}
+
+/// Acquires the RCU read side lock.
+pub fn read_lock() -> Guard {
+    Guard::new()
+}
diff --git a/rust/kernel/sync/revocable.rs b/rust/kernel/sync/revocable.rs
new file mode 100644
index 000000000000..8fd7f07f2a65
--- /dev/null
+++ b/rust/kernel/sync/revocable.rs
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Synchronisation primitives where access to their contents can be revoked at runtime.
+
+use crate::{
+    str::CStr,
+    sync::{Guard, Lock, LockClassKey, LockFactory, LockInfo, NeedsLockClass, ReadLock, WriteLock},
+    True,
+};
+use core::{
+    mem::MaybeUninit,
+    ops::{Deref, DerefMut},
+    pin::Pin,
+};
+
+/// The state within the revocable synchronisation primitive.
+///
+/// We don't use simply `Option<T>` because we need to drop in-place because the contents are
+/// implicitly pinned.
+///
+/// # Invariants
+///
+/// The `is_available` field determines if `data` is initialised.
+pub struct Inner<T> {
+    is_available: bool,
+    data: MaybeUninit<T>,
+}
+
+impl<T> Inner<T> {
+    fn new(data: T) -> Self {
+        // INVARIANT: `data` is initialised and `is_available` is `true`, so the state matches.
+        Self {
+            is_available: true,
+            data: MaybeUninit::new(data),
+        }
+    }
+
+    fn drop_in_place(&mut self) {
+        if !self.is_available {
+            // Already dropped.
+            return;
+        }
+
+        // INVARIANT: `data` is being dropped and `is_available` is set to `false`, so the state
+        // matches.
+        self.is_available = false;
+
+        // SAFETY: By the type invariants, `data` is valid because `is_available` was true.
+        unsafe { self.data.assume_init_drop() };
+    }
+}
+
+impl<T> Drop for Inner<T> {
+    fn drop(&mut self) {
+        self.drop_in_place();
+    }
+}
+
+/// Revocable synchronisation primitive.
+///
+/// That is, it wraps synchronisation primitives so that access to their contents can be revoked at
+/// runtime, rendering them inacessible.
+///
+/// Once access is revoked and all concurrent users complete (i.e., all existing instances of
+/// [`RevocableGuard`] are dropped), the wrapped object is also dropped.
+///
+/// For better ergonomics, we advise the use of specialisations of this struct, for example,
+/// [`super::RevocableMutex`] and [`super::RevocableRwSemaphore`]. Callers that do not need to
+/// sleep while holding on to a guard should use [`crate::revocable::Revocable`] instead, which is
+/// more efficient as it uses RCU to keep objects alive.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::{Mutex, Revocable};
+/// # use kernel::revocable_init;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// fn add_two(v: &Revocable<Mutex<()>, Example>) -> Option<u32> {
+///     let mut guard = v.try_write()?;
+///     guard.a += 2;
+///     guard.b += 2;
+///     Some(guard.a + guard.b)
+/// }
+///
+/// // SAFETY: We call `revocable_init` immediately below.
+/// let mut v = unsafe { Revocable::<Mutex<()>, Example>::new(Example { a: 10, b: 20 }) };
+/// // SAFETY: We never move out of `v`.
+/// let pinned = unsafe { Pin::new_unchecked(&mut v) };
+/// revocable_init!(pinned, "example::v");
+/// assert_eq!(add_two(&v), Some(34));
+/// v.revoke();
+/// assert_eq!(add_two(&v), None);
+/// ```
+pub struct Revocable<F: LockFactory, T> {
+    inner: F::LockedType<Inner<T>>,
+}
+
+/// Safely initialises a [`Revocable`] instance with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! revocable_init {
+    ($mutex:expr, $name:literal) => {
+        $crate::init_with_lockdep!($mutex, $name)
+    };
+}
+
+impl<F: LockFactory, T> Revocable<F, T> {
+    /// Creates a new revocable instance of the given lock.
+    ///
+    /// # Safety
+    ///
+    /// The caller must call [`Revocable::init`] before using the revocable synch primitive.
+    pub unsafe fn new(data: T) -> Self {
+        Self {
+            // SAFETY: The safety requirements of this function require that `Revocable::init`
+            // be called before the returned object can be used. Lock initialisation is called
+            // from `Revocable::init`.
+            inner: unsafe { F::new_lock(Inner::new(data)) },
+        }
+    }
+}
+
+impl<F: LockFactory, T> NeedsLockClass for Revocable<F, T>
+where
+    F::LockedType<Inner<T>>: NeedsLockClass,
+{
+    fn init(
+        self: Pin<&mut Self>,
+        name: &'static CStr,
+        key1: &'static LockClassKey,
+        key2: &'static LockClassKey,
+    ) {
+        // SAFETY: `inner` is pinned when `self` is.
+        let inner = unsafe { self.map_unchecked_mut(|r| &mut r.inner) };
+        inner.init(name, key1, key2);
+    }
+}
+
+impl<F: LockFactory, T> Revocable<F, T>
+where
+    F::LockedType<Inner<T>>: Lock<Inner = Inner<T>>,
+{
+    /// Revokes access to and drops the wrapped object.
+    ///
+    /// Revocation and dropping happen after ongoing accessors complete.
+    pub fn revoke(&self) {
+        self.lock().drop_in_place();
+    }
+
+    /// Tries to lock the \[revocable\] wrapped object in write (exclusive) mode.
+    ///
+    /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+    ///
+    /// Returns a guard that gives access to the object otherwise; the object is guaranteed to
+    /// remain accessible while the guard is alive. Callers are allowed to sleep while holding on
+    /// to the returned guard.
+    pub fn try_write(&self) -> Option<RevocableGuard<'_, F, T, WriteLock>> {
+        let inner = self.lock();
+        if !inner.is_available {
+            return None;
+        }
+        Some(RevocableGuard::new(inner))
+    }
+
+    fn lock(&self) -> Guard<'_, F::LockedType<Inner<T>>> {
+        let ctx = self.inner.lock_noguard();
+        // SAFETY: The lock was acquired in the call above.
+        unsafe { Guard::new(&self.inner, ctx) }
+    }
+}
+
+impl<F: LockFactory, T> Revocable<F, T>
+where
+    F::LockedType<Inner<T>>: Lock<ReadLock, Inner = Inner<T>>,
+{
+    /// Tries to lock the \[revocable\] wrapped object in read (shared) mode.
+    ///
+    /// Returns `None` if the object has been revoked and is therefore no longer accessible.
+    ///
+    /// Returns a guard that gives access to the object otherwise; the object is guaranteed to
+    /// remain accessible while the guard is alive. Callers are allowed to sleep while holding on
+    /// to the returned guard.
+    pub fn try_read(&self) -> Option<RevocableGuard<'_, F, T, ReadLock>> {
+        let ctx = self.inner.lock_noguard();
+        // SAFETY: The lock was acquired in the call above.
+        let inner = unsafe { Guard::new(&self.inner, ctx) };
+        if !inner.is_available {
+            return None;
+        }
+        Some(RevocableGuard::new(inner))
+    }
+}
+
+/// A guard that allows access to a revocable object and keeps it alive.
+pub struct RevocableGuard<'a, F: LockFactory, T, I: LockInfo>
+where
+    F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+    guard: Guard<'a, F::LockedType<Inner<T>>, I>,
+}
+
+impl<'a, F: LockFactory, T, I: LockInfo> RevocableGuard<'a, F, T, I>
+where
+    F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+    fn new(guard: Guard<'a, F::LockedType<Inner<T>>, I>) -> Self {
+        Self { guard }
+    }
+}
+
+impl<F: LockFactory, T, I: LockInfo<Writable = True>> RevocableGuard<'_, F, T, I>
+where
+    F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+    /// Returns a pinned mutable reference to the wrapped object.
+    pub fn as_pinned_mut(&mut self) -> Pin<&mut T> {
+        // SAFETY: Revocable mutexes must be pinned, so we choose to always project the data as
+        // pinned as well (i.e., we guarantee we never move it).
+        unsafe { Pin::new_unchecked(&mut *self) }
+    }
+}
+
+impl<F: LockFactory, T, I: LockInfo> Deref for RevocableGuard<'_, F, T, I>
+where
+    F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        unsafe { &*self.guard.data.as_ptr() }
+    }
+}
+
+impl<F: LockFactory, T, I: LockInfo<Writable = True>> DerefMut for RevocableGuard<'_, F, T, I>
+where
+    F::LockedType<Inner<T>>: Lock<I, Inner = Inner<T>>,
+{
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        unsafe { &mut *self.guard.data.as_mut_ptr() }
+    }
+}
diff --git a/rust/kernel/sync/rwsem.rs b/rust/kernel/sync/rwsem.rs
new file mode 100644
index 000000000000..6556d7d30d36
--- /dev/null
+++ b/rust/kernel/sync/rwsem.rs
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A kernel read/write mutex.
+//!
+//! This module allows Rust code to use the kernel's [`struct rw_semaphore`].
+//!
+//! C header: [`include/linux/rwsem.h`](../../../../include/linux/rwsem.h)
+
+use super::{
+    mutex::EmptyGuardContext, Guard, Lock, LockClassKey, LockFactory, LockIniter, ReadLock,
+    WriteLock,
+};
+use crate::{bindings, str::CStr, Opaque};
+use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin};
+
+/// Safely initialises a [`RwSemaphore`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! rwsemaphore_init {
+    ($rwsem:expr, $name:literal) => {
+        $crate::init_with_lockdep!($rwsem, $name)
+    };
+}
+
+/// Exposes the kernel's [`struct rw_semaphore`].
+///
+/// It's a read/write mutex. That is, it allows multiple readers to acquire it concurrently, but
+/// only one writer at a time. On contention, waiters sleep.
+///
+/// A [`RwSemaphore`] must first be initialised with a call to [`RwSemaphore::init_lock`] before it
+/// can be used. The [`rwsemaphore_init`] macro is provided to automatically assign a new lock
+/// class to an [`RwSemaphore`] instance.
+///
+/// Since it may block, [`RwSemaphore`] needs to be used with care in atomic contexts.
+///
+/// [`struct rw_semaphore`]: ../../../include/linux/rwsem.h
+pub struct RwSemaphore<T: ?Sized> {
+    /// The kernel `struct rw_semaphore` object.
+    rwsem: Opaque<bindings::rw_semaphore>,
+
+    /// An rwsem needs to be pinned because it contains a [`struct list_head`] that is
+    /// self-referential, so it cannot be safely moved once it is initialised.
+    _pin: PhantomPinned,
+
+    /// The data protected by the rwsem.
+    data: UnsafeCell<T>,
+}
+
+// SAFETY: `RwSemaphore` can be transferred across thread boundaries iff the data it protects can.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: ?Sized + Send> Send for RwSemaphore<T> {}
+
+// SAFETY: `RwSemaphore` requires that the protected type be `Sync` for it to be `Sync` as well
+// because the read mode allows multiple threads to access the protected data concurrently. It
+// requires `Send` because the write lock allows a `&mut T` to be accessible from an arbitrary
+// thread.
+unsafe impl<T: ?Sized + Send + Sync> Sync for RwSemaphore<T> {}
+
+impl<T> RwSemaphore<T> {
+    /// Constructs a new rw semaphore.
+    ///
+    /// # Safety
+    ///
+    /// The caller must call [`RwSemaphore::init_lock`] before using the rw semaphore.
+    pub unsafe fn new(t: T) -> Self {
+        Self {
+            rwsem: Opaque::uninit(),
+            data: UnsafeCell::new(t),
+            _pin: PhantomPinned,
+        }
+    }
+}
+
+impl<T: ?Sized> RwSemaphore<T> {
+    /// Locks the rw semaphore in write (exclusive) mode and gives the caller access to the data
+    /// protected by it. Only one thread at a time is allowed to access the protected data.
+    pub fn write(&self) -> Guard<'_, Self> {
+        let ctx = <Self as Lock>::lock_noguard(self);
+        // SAFETY: The rw semaphore was just acquired in write mode.
+        unsafe { Guard::new(self, ctx) }
+    }
+
+    /// Locks the rw semaphore in read (shared) mode and gives the caller access to the data
+    /// protected by it. Only one thread at a time is allowed to access the protected data.
+    pub fn read(&self) -> Guard<'_, Self, ReadLock> {
+        let ctx = <Self as Lock<ReadLock>>::lock_noguard(self);
+        // SAFETY: The rw semaphore was just acquired in read mode.
+        unsafe { Guard::new(self, ctx) }
+    }
+}
+
+impl<T> LockFactory for RwSemaphore<T> {
+    type LockedType<U> = RwSemaphore<U>;
+
+    unsafe fn new_lock<U>(data: U) -> RwSemaphore<U> {
+        // SAFETY: The safety requirements of `new_lock` also require that `init_lock` be called.
+        unsafe { RwSemaphore::new(data) }
+    }
+}
+
+impl<T> LockIniter for RwSemaphore<T> {
+    fn init_lock(self: Pin<&mut Self>, name: &'static CStr, key: &'static LockClassKey) {
+        unsafe { bindings::__init_rwsem(self.rwsem.get(), name.as_char_ptr(), key.get()) };
+    }
+}
+
+// SAFETY: The underlying kernel `struct rw_semaphore` object ensures mutual exclusion because it's
+// acquired in write mode.
+unsafe impl<T: ?Sized> Lock for RwSemaphore<T> {
+    type Inner = T;
+    type GuardContext = EmptyGuardContext;
+
+    fn lock_noguard(&self) -> EmptyGuardContext {
+        // SAFETY: `rwsem` points to valid memory.
+        unsafe { bindings::down_write(self.rwsem.get()) };
+        EmptyGuardContext
+    }
+
+    unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+        // SAFETY: The safety requirements of the function ensure that the rw semaphore is owned by
+        // the caller.
+        unsafe { bindings::up_write(self.rwsem.get()) };
+    }
+
+    fn locked_data(&self) -> &UnsafeCell<T> {
+        &self.data
+    }
+}
+
+// SAFETY: The underlying kernel `struct rw_semaphore` object ensures that only shared references
+// are accessible from other threads because it's acquired in read mode.
+unsafe impl<T: ?Sized> Lock<ReadLock> for RwSemaphore<T> {
+    type Inner = T;
+    type GuardContext = EmptyGuardContext;
+
+    fn lock_noguard(&self) -> EmptyGuardContext {
+        // SAFETY: `rwsem` points to valid memory.
+        unsafe { bindings::down_read(self.rwsem.get()) };
+        EmptyGuardContext
+    }
+
+    unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+        // SAFETY: The safety requirements of the function ensure that the rw semaphore is owned by
+        // the caller.
+        unsafe { bindings::up_read(self.rwsem.get()) };
+    }
+
+    fn locked_data(&self) -> &UnsafeCell<T> {
+        &self.data
+    }
+}
+
+/// A revocable rw semaphore.
+///
+/// That is, a read/write semaphore to which access can be revoked at runtime. It is a
+/// specialisation of the more generic [`super::revocable::Revocable`].
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::RevocableRwSemaphore;
+/// # use kernel::revocable_init;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// fn read_sum(v: &RevocableRwSemaphore<Example>) -> Option<u32> {
+///     let guard = v.try_read()?;
+///     Some(guard.a + guard.b)
+/// }
+///
+/// fn add_two(v: &RevocableRwSemaphore<Example>) -> Option<u32> {
+///     let mut guard = v.try_write()?;
+///     guard.a += 2;
+///     guard.b += 2;
+///     Some(guard.a + guard.b)
+/// }
+///
+/// // SAFETY: We call `revocable_init` immediately below.
+/// let mut v = unsafe { RevocableRwSemaphore::new(Example { a: 10, b: 20 }) };
+/// // SAFETY: We never move out of `v`.
+/// let pinned = unsafe { Pin::new_unchecked(&mut v) };
+/// revocable_init!(pinned, "example::v");
+/// assert_eq!(read_sum(&v), Some(30));
+/// assert_eq!(add_two(&v), Some(34));
+/// v.revoke();
+/// assert_eq!(read_sum(&v), None);
+/// assert_eq!(add_two(&v), None);
+/// ```
+pub type RevocableRwSemaphore<T> = super::revocable::Revocable<RwSemaphore<()>, T>;
+
+/// A guard for a revocable rw semaphore..
+pub type RevocableRwSemaphoreGuard<'a, T, I = WriteLock> =
+    super::revocable::RevocableGuard<'a, RwSemaphore<()>, T, I>;
diff --git a/rust/kernel/sync/seqlock.rs b/rust/kernel/sync/seqlock.rs
new file mode 100644
index 000000000000..5014e70621f6
--- /dev/null
+++ b/rust/kernel/sync/seqlock.rs
@@ -0,0 +1,201 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A kernel sequential lock (seqlock).
+//!
+//! This module allows Rust code to use the sequential locks based on the kernel's `seqcount_t` and
+//! any locks implementing the [`LockFactory`] trait.
+//!
+//! See <https://www.kernel.org/doc/Documentation/locking/seqlock.rst>.
+
+use super::{Guard, Lock, LockClassKey, LockFactory, LockIniter, NeedsLockClass, ReadLock};
+use crate::{bindings, str::CStr, Opaque};
+use core::{cell::UnsafeCell, marker::PhantomPinned, ops::Deref, pin::Pin};
+
+/// Exposes sequential locks backed by the kernel's `seqcount_t`.
+///
+/// The write-side critical section is protected by a lock implementing the [`LockFactory`] trait.
+///
+/// # Examples
+///
+/// ```
+/// use core::sync::atomic::{AtomicU32, Ordering};
+/// use kernel::sync::{SeqLock, SpinLock};
+///
+/// struct Example {
+///     a: AtomicU32,
+///     b: AtomicU32,
+/// }
+///
+/// fn get_sum(v: &SeqLock<SpinLock<Example>>) -> u32 {
+///     // Use `access` to access the fields of `Example`.
+///     v.access(|e| e.a.load(Ordering::Relaxed) + e.b.load(Ordering::Relaxed))
+/// }
+///
+/// fn get_sum_with_guard(v: &SeqLock<SpinLock<Example>>) -> u32 {
+///     // Use `read` and `need_retry` in a loop to access the fields of `Example`.
+///     loop {
+///         let guard = v.read();
+///         let sum = guard.a.load(Ordering::Relaxed) + guard.b.load(Ordering::Relaxed);
+///         if !guard.need_retry() {
+///             break sum;
+///         }
+///     }
+/// }
+///
+/// fn inc_each(v: &SeqLock<SpinLock<Example>>) {
+///     // Use a write-side guard to access the fields of `Example`.
+///     let guard = v.write();
+///     let a = guard.a.load(Ordering::Relaxed);
+///     guard.a.store(a + 1, Ordering::Relaxed);
+///     let b = guard.b.load(Ordering::Relaxed);
+///     guard.b.store(b + 1, Ordering::Relaxed);
+/// }
+/// ```
+pub struct SeqLock<L: Lock + ?Sized> {
+    _p: PhantomPinned,
+    count: Opaque<bindings::seqcount>,
+    write_lock: L,
+}
+
+// SAFETY: `SeqLock` can be transferred across thread boundaries iff the data it protects and the
+// underlying lock can.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<L: Lock + Send> Send for SeqLock<L> where L::Inner: Send {}
+
+// SAFETY: `SeqLock` allows concurrent access to the data it protects by both readers and writers,
+// so it requires that the data it protects be `Sync`, as well as the underlying lock.
+unsafe impl<L: Lock + Sync> Sync for SeqLock<L> where L::Inner: Sync {}
+
+impl<L: Lock> SeqLock<L> {
+    /// Constructs a new instance of [`SeqLock`].
+    ///
+    /// # Safety
+    ///
+    /// The caller must call [`SeqLock::init`] before using the seqlock.
+    pub unsafe fn new(data: L::Inner) -> Self
+    where
+        L: LockFactory<LockedType<L::Inner> = L>,
+        L::Inner: Sized,
+    {
+        Self {
+            _p: PhantomPinned,
+            count: Opaque::uninit(),
+            // SAFETY: `L::init_lock` is called from `SeqLock::init`, which is required to be
+            // called by the function's safety requirements.
+            write_lock: unsafe { L::new_lock(data) },
+        }
+    }
+}
+
+impl<L: Lock + ?Sized> SeqLock<L> {
+    /// Accesses the protected data in read mode.
+    ///
+    /// Readers and writers are allowed to run concurrently, so callers must check if they need to
+    /// refetch the values before they are used (e.g., because a writer changed them concurrently,
+    /// rendering them potentially inconsistent). The check is performed via calls to
+    /// [`SeqLockReadGuard::need_retry`].
+    pub fn read(&self) -> SeqLockReadGuard<'_, L> {
+        SeqLockReadGuard {
+            lock: self,
+            // SAFETY: `count` contains valid memory.
+            start_count: unsafe { bindings::read_seqcount_begin(self.count.get()) },
+        }
+    }
+
+    /// Accesses the protected data in read mode.
+    ///
+    /// The provided closure is called repeatedly if it may have accessed inconsistent data (e.g.,
+    /// because a concurrent writer modified it). This is a wrapper around [`SeqLock::read`] and
+    /// [`SeqLockReadGuard::need_retry`] in a loop.
+    pub fn access<F: Fn(&L::Inner) -> R, R>(&self, cb: F) -> R {
+        loop {
+            let guard = self.read();
+            let ret = cb(&guard);
+            if !guard.need_retry() {
+                return ret;
+            }
+        }
+    }
+
+    /// Locks the underlying lock and returns a guard that allows access to the protected data.
+    ///
+    /// The guard is not mutable though because readers are still allowed to concurrently access
+    /// the data. The protected data structure needs to provide interior mutability itself (e.g.,
+    /// via atomic types) for the individual fields that can be mutated.
+    pub fn write(&self) -> Guard<'_, Self, ReadLock> {
+        let ctx = self.lock_noguard();
+        // SAFETY: The seqlock was just acquired.
+        unsafe { Guard::new(self, ctx) }
+    }
+}
+
+impl<L: LockIniter + Lock + ?Sized> NeedsLockClass for SeqLock<L> {
+    fn init(
+        mut self: Pin<&mut Self>,
+        name: &'static CStr,
+        key1: &'static LockClassKey,
+        key2: &'static LockClassKey,
+    ) {
+        // SAFETY: `write_lock` is pinned when `self` is.
+        let pinned = unsafe { self.as_mut().map_unchecked_mut(|s| &mut s.write_lock) };
+        pinned.init_lock(name, key1);
+        // SAFETY: `key2` is valid as it has a static lifetime.
+        unsafe { bindings::__seqcount_init(self.count.get(), name.as_char_ptr(), key2.get()) };
+    }
+}
+
+// SAFETY: The underlying lock ensures mutual exclusion.
+unsafe impl<L: Lock + ?Sized> Lock<ReadLock> for SeqLock<L> {
+    type Inner = L::Inner;
+    type GuardContext = L::GuardContext;
+
+    fn lock_noguard(&self) -> L::GuardContext {
+        let ctx = self.write_lock.lock_noguard();
+        // SAFETY: `count` contains valid memory.
+        unsafe { bindings::write_seqcount_begin(self.count.get()) };
+        ctx
+    }
+
+    fn relock(&self, ctx: &mut L::GuardContext) {
+        self.write_lock.relock(ctx);
+        // SAFETY: `count` contains valid memory.
+        unsafe { bindings::write_seqcount_begin(self.count.get()) };
+    }
+
+    unsafe fn unlock(&self, ctx: &mut L::GuardContext) {
+        // SAFETY: The safety requirements of the function ensure that lock is owned by the caller.
+        unsafe { bindings::write_seqcount_end(self.count.get()) };
+        // SAFETY: The safety requirements of the function ensure that lock is owned by the caller.
+        unsafe { self.write_lock.unlock(ctx) };
+    }
+
+    fn locked_data(&self) -> &UnsafeCell<L::Inner> {
+        self.write_lock.locked_data()
+    }
+}
+
+/// Allows read-side access to data protected by a sequential lock.
+pub struct SeqLockReadGuard<'a, L: Lock + ?Sized> {
+    lock: &'a SeqLock<L>,
+    start_count: u32,
+}
+
+impl<L: Lock + ?Sized> SeqLockReadGuard<'_, L> {
+    /// Determine if the callers needs to retry reading values.
+    ///
+    /// It returns `true` when a concurrent writer ran between the guard being created and
+    /// [`Self::need_retry`] being called.
+    pub fn need_retry(&self) -> bool {
+        // SAFETY: `count` is valid because the guard guarantees that the lock remains alive.
+        unsafe { bindings::read_seqcount_retry(self.lock.count.get(), self.start_count) != 0 }
+    }
+}
+
+impl<L: Lock + ?Sized> Deref for SeqLockReadGuard<'_, L> {
+    type Target = L::Inner;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: We only ever allow shared access to the protected data.
+        unsafe { &*self.lock.locked_data().get() }
+    }
+}
diff --git a/rust/kernel/sync/smutex.rs b/rust/kernel/sync/smutex.rs
new file mode 100644
index 000000000000..e19dd966640a
--- /dev/null
+++ b/rust/kernel/sync/smutex.rs
@@ -0,0 +1,290 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A simple mutex implementation.
+//!
+//! Differently from [`super::Mutex`], this implementation does not require pinning, so the
+//! ergonomics are much improved, though the implementation is not as feature-rich as the C-based
+//! one. The main advantage is that it doesn't impose unsafe blocks on callers.
+//!
+//! The mutex is made up of 2 words in addition to the data it protects. The first one is accessed
+//! concurrently by threads trying to acquire and release the mutex, it contains a "stack" of
+//! waiters and a "locked" bit; the second one is only accessible by the thread holding the mutex,
+//! it contains a queue of waiters. Waiters are moved from the stack to the queue when the mutex is
+//! next unlocked while the stack is non-empty and the queue is empty. A single waiter is popped
+//! from the wait queue when the owner of the mutex unlocks it.
+//!
+//! The initial state of the mutex is `<locked=0, stack=[], queue=[]>`, meaning that it isn't
+//! locked and both the waiter stack and queue are empty.
+//!
+//! A lock operation transitions the mutex to state `<locked=1, stack=[], queue=[]>`.
+//!
+//! An unlock operation transitions the mutex back to the initial state, however, an attempt to
+//! lock the mutex while it's already locked results in a waiter being created (on the stack) and
+//! pushed onto the stack, so the state is `<locked=1, stack=[W1], queue=[]>`.
+//!
+//! Another thread trying to lock the mutex results in another waiter being pushed onto the stack,
+//! so the state becomes `<locked=1, stack=[W2, W1], queue=[]>`.
+//!
+//! In such states (queue is empty but stack is non-empty), the unlock operation is performed in
+//! three steps:
+//! 1. The stack is popped (but the mutex remains locked), so the state is:
+//!    `<locked=1, stack=[], queue=[]>`
+//! 2. The stack is turned into a queue by reversing it, so the state is:
+//!    `<locked=1, stack=[], queue=[W1, W2]>
+//! 3. Finally, the lock is released, and the first waiter is awakened, so the state is:
+//!    `<locked=0, stack=[], queue=[W2]>`
+//!
+//! The mutex remains accessible to any threads attempting to lock it in any of the intermediate
+//! states above. For example, while it is locked, other threads may add waiters to the stack
+//! (which is ok because we want to release the ones on the queue first); another example is that
+//! another thread may acquire the mutex before waiter W1 in the example above, this makes the
+//! mutex unfair but this is desirable because the thread is running already and may in fact
+//! release the lock before W1 manages to get scheduled -- it also mitigates the lock convoy
+//! problem when the releasing thread wants to immediately acquire the lock again: it will be
+//! allowed to do so (as long as W1 doesn't get to it first).
+//!
+//! When the waiter queue is non-empty, unlocking the mutex always results in the first waiter being
+//! popped form the queue and awakened.
+
+use super::{mutex::EmptyGuardContext, Guard, Lock, LockClassKey, LockFactory, LockIniter};
+use crate::{bindings, str::CStr, Opaque};
+use core::sync::atomic::{AtomicUsize, Ordering};
+use core::{cell::UnsafeCell, pin::Pin};
+
+/// The value that is OR'd into the [`Mutex::waiter_stack`] when the mutex is locked.
+const LOCKED: usize = 1;
+
+/// A simple mutex.
+///
+/// This is mutual-exclusion primitive. It guarantees that only one thread at a time may access the
+/// data it protects. When multiple threads attempt to lock the same mutex, only one at a time is
+/// allowed to progress, the others will block (sleep) until the mutex is unlocked, at which point
+/// another thread will be allowed to wake up and make progress.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::{Result, sync::Ref, sync::smutex::Mutex};
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// static EXAMPLE: Mutex<Example> = Mutex::new(Example { a: 10, b: 20 });
+///
+/// fn inc_a(example: &Mutex<Example>) {
+///     let mut guard = example.lock();
+///     guard.a += 1;
+/// }
+///
+/// fn sum(example: &Mutex<Example>) -> u32 {
+///     let guard = example.lock();
+///     guard.a + guard.b
+/// }
+///
+/// fn try_new(a: u32, b: u32) -> Result<Ref<Mutex<Example>>> {
+///     Ref::try_new(Mutex::new(Example { a, b }))
+/// }
+///
+/// assert_eq!(EXAMPLE.lock().a, 10);
+/// assert_eq!(sum(&EXAMPLE), 30);
+///
+/// inc_a(&EXAMPLE);
+///
+/// assert_eq!(EXAMPLE.lock().a, 11);
+/// assert_eq!(sum(&EXAMPLE), 31);
+///
+/// # try_new(42, 43);
+/// ```
+pub struct Mutex<T: ?Sized> {
+    /// A stack of waiters.
+    ///
+    /// It is accessed atomically by threads lock/unlocking the mutex. Additionally, the
+    /// least-significant bit is used to indicate whether the mutex is locked or not.
+    waiter_stack: AtomicUsize,
+
+    /// A queue of waiters.
+    ///
+    /// This is only accessible to the holder of the mutex. When the owner of the mutex is
+    /// unlocking it, it will move waiters from the stack to the queue when the queue is empty and
+    /// the stack non-empty.
+    waiter_queue: UnsafeCell<*mut Waiter>,
+
+    /// The data protected by the mutex.
+    data: UnsafeCell<T>,
+}
+
+// SAFETY: `Mutex` can be transferred across thread boundaries iff the data it protects can.
+#[allow(clippy::non_send_fields_in_send_ty)]
+unsafe impl<T: ?Sized + Send> Send for Mutex<T> {}
+
+// SAFETY: `Mutex` serialises the interior mutability it provides, so it is `Sync` as long as the
+// data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for Mutex<T> {}
+
+impl<T> Mutex<T> {
+    /// Creates a new instance of the mutex.
+    pub const fn new(data: T) -> Self {
+        Self {
+            waiter_stack: AtomicUsize::new(0),
+            waiter_queue: UnsafeCell::new(core::ptr::null_mut()),
+            data: UnsafeCell::new(data),
+        }
+    }
+}
+
+impl<T: ?Sized> Mutex<T> {
+    /// Locks the mutex and gives the caller access to the data protected by it. Only one thread at
+    /// a time is allowed to access the protected data.
+    pub fn lock(&self) -> Guard<'_, Self> {
+        let ctx = self.lock_noguard();
+        // SAFETY: The mutex was just acquired.
+        unsafe { Guard::new(self, ctx) }
+    }
+}
+
+impl<T> LockFactory for Mutex<T> {
+    type LockedType<U> = Mutex<U>;
+
+    unsafe fn new_lock<U>(data: U) -> Mutex<U> {
+        Mutex::new(data)
+    }
+}
+
+impl<T> LockIniter for Mutex<T> {
+    fn init_lock(self: Pin<&mut Self>, _name: &'static CStr, _key: &'static LockClassKey) {}
+}
+
+// SAFETY: The mutex implementation ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock for Mutex<T> {
+    type Inner = T;
+    type GuardContext = EmptyGuardContext;
+
+    fn lock_noguard(&self) -> EmptyGuardContext {
+        loop {
+            // Try the fast path: the caller owns the mutex if we manage to set the `LOCKED` bit.
+            //
+            // The `acquire` order matches with one of the `release` ones in `unlock`.
+            if self.waiter_stack.fetch_or(LOCKED, Ordering::Acquire) & LOCKED == 0 {
+                return EmptyGuardContext;
+            }
+
+            // Slow path: we'll likely need to wait, so initialise a local waiter struct.
+            let mut waiter = Waiter {
+                completion: Opaque::uninit(),
+                next: core::ptr::null_mut(),
+            };
+
+            // SAFETY: The completion object was just allocated on the stack and is valid for
+            // writes.
+            unsafe { bindings::init_completion(waiter.completion.get()) };
+
+            // Try to enqueue the waiter by pushing into onto the waiter stack. We want to do it
+            // only while the mutex is locked by another thread.
+            loop {
+                // We use relaxed here because we're just reading the value we'll CAS later (which
+                // has a stronger ordering on success).
+                let mut v = self.waiter_stack.load(Ordering::Relaxed);
+                if v & LOCKED == 0 {
+                    // The mutex was released by another thread, so try to acquire it.
+                    //
+                    // The `acquire` order matches with one of the `release` ones in `unlock`.
+                    v = self.waiter_stack.fetch_or(LOCKED, Ordering::Acquire);
+                    if v & LOCKED == 0 {
+                        return EmptyGuardContext;
+                    }
+                }
+
+                waiter.next = (v & !LOCKED) as _;
+
+                // The `release` order matches with `acquire` in `unlock` when the stack is swapped
+                // out. We use release order here to ensure that the other thread can see our
+                // waiter fully initialised.
+                if self
+                    .waiter_stack
+                    .compare_exchange(
+                        v,
+                        (&mut waiter as *mut _ as usize) | LOCKED,
+                        Ordering::Release,
+                        Ordering::Relaxed,
+                    )
+                    .is_ok()
+                {
+                    break;
+                }
+            }
+
+            // Wait for the owner to lock to wake this thread up.
+            //
+            // SAFETY: Completion object was previously initialised with `init_completion` and
+            // remains valid.
+            unsafe { bindings::wait_for_completion(waiter.completion.get()) };
+        }
+    }
+
+    unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+        // SAFETY: The caller owns the mutex, so it is safe to manipulate the local wait queue.
+        let mut waiter = unsafe { *self.waiter_queue.get() };
+        loop {
+            // If we have a non-empty local queue of waiters, pop the first one, release the mutex,
+            // and wake it up (the popped waiter).
+            if !waiter.is_null() {
+                // SAFETY: The caller owns the mutex, so it is safe to manipulate the local wait
+                // queue.
+                unsafe { *self.waiter_queue.get() = (*waiter).next };
+
+                // The `release` order matches with one of the `acquire` ones in `lock_noguard`.
+                self.waiter_stack.fetch_and(!LOCKED, Ordering::Release);
+
+                // Wake up the first waiter.
+                //
+                // SAFETY: The completion object was initialised before being added to the wait
+                // stack and is only removed above, when called completed. So it is safe for
+                // writes.
+                unsafe { bindings::complete_all((*waiter).completion.get()) };
+                return;
+            }
+
+            // Try the fast path when there are no local waiters.
+            //
+            // The `release` order matches with one of the `acquire` ones in `lock_noguard`.
+            if self
+                .waiter_stack
+                .compare_exchange(LOCKED, 0, Ordering::Release, Ordering::Relaxed)
+                .is_ok()
+            {
+                return;
+            }
+
+            // We don't have a local queue, so pull the whole stack off, reverse it, and use it as a
+            // local queue. Since we're manipulating this queue, we need to keep ownership of the
+            // mutex.
+            //
+            // The `acquire` order matches with the `release` one in `lock_noguard` where a waiter
+            // is pushed onto the stack. It ensures that we see the fully-initialised waiter.
+            let mut stack =
+                (self.waiter_stack.swap(LOCKED, Ordering::Acquire) & !LOCKED) as *mut Waiter;
+            while !stack.is_null() {
+                // SAFETY: The caller still owns the mutex, so it is safe to manipulate the
+                // elements of the wait queue, which will soon become that wait queue.
+                let next = unsafe { (*stack).next };
+
+                // SAFETY: Same as above.
+                unsafe { (*stack).next = waiter };
+
+                waiter = stack;
+                stack = next;
+            }
+        }
+    }
+
+    fn locked_data(&self) -> &UnsafeCell<T> {
+        &self.data
+    }
+}
+
+struct Waiter {
+    completion: Opaque<bindings::completion>,
+    next: *mut Waiter,
+}
diff --git a/rust/kernel/sync/spinlock.rs b/rust/kernel/sync/spinlock.rs
new file mode 100644
index 000000000000..b326af4196bb
--- /dev/null
+++ b/rust/kernel/sync/spinlock.rs
@@ -0,0 +1,357 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! A kernel spinlock.
+//!
+//! This module allows Rust code to use the kernel's [`struct spinlock`].
+//!
+//! See <https://www.kernel.org/doc/Documentation/locking/spinlocks.txt>.
+
+use super::{
+    mutex::EmptyGuardContext, Guard, Lock, LockClassKey, LockFactory, LockInfo, LockIniter,
+    WriteLock,
+};
+use crate::{bindings, str::CStr, Opaque, True};
+use core::{cell::UnsafeCell, marker::PhantomPinned, pin::Pin};
+
+/// Safely initialises a [`SpinLock`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! spinlock_init {
+    ($spinlock:expr, $name:literal) => {
+        $crate::init_with_lockdep!($spinlock, $name)
+    };
+}
+
+/// Exposes the kernel's [`spinlock_t`]. When multiple CPUs attempt to lock the same spinlock, only
+/// one at a time is allowed to progress, the others will block (spinning) until the spinlock is
+/// unlocked, at which point another CPU will be allowed to make progress.
+///
+/// A [`SpinLock`] must first be initialised with a call to [`SpinLock::init_lock`] before it can be
+/// used. The [`spinlock_init`] macro is provided to automatically assign a new lock class to a
+/// spinlock instance.
+///
+/// There are two ways to acquire the lock:
+///  - [`SpinLock::lock`], which doesn't manage interrupt state, so it should be used in only two
+///    cases: (a) when the caller knows that interrupts are disabled, or (b) when callers never use
+///    it in atomic context (e.g., interrupt handlers), in which case it is ok for interrupts to be
+///    enabled.
+///  - [`SpinLock::lock_irqdisable`], which disables interrupts if they are enabled before
+///    acquiring the lock. When the lock is released, the interrupt state is automatically returned
+///    to its value before [`SpinLock::lock_irqdisable`] was called.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::SpinLock;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// // Function that acquires spinlock without changing interrupt state.
+/// fn lock_example(value: &SpinLock<Example>) {
+///     let mut guard = value.lock();
+///     guard.a = 10;
+///     guard.b = 20;
+/// }
+///
+/// // Function that acquires spinlock and disables interrupts while holding it.
+/// fn lock_irqdisable_example(value: &SpinLock<Example>) {
+///     let mut guard = value.lock_irqdisable();
+///     guard.a = 30;
+///     guard.b = 40;
+/// }
+///
+/// // Initialises a spinlock.
+/// // SAFETY: `spinlock_init` is called below.
+/// let mut value = unsafe { SpinLock::new(Example { a: 1, b: 2 }) };
+/// // SAFETY: We don't move `value`.
+/// kernel::spinlock_init!(unsafe { Pin::new_unchecked(&mut value) }, "value");
+///
+/// // Calls the example functions.
+/// assert_eq!(value.lock().a, 1);
+/// lock_example(&value);
+/// assert_eq!(value.lock().a, 10);
+/// lock_irqdisable_example(&value);
+/// assert_eq!(value.lock().a, 30);
+/// ```
+///
+/// [`spinlock_t`]: ../../../include/linux/spinlock.h
+pub struct SpinLock<T: ?Sized> {
+    spin_lock: Opaque<bindings::spinlock>,
+
+    /// Spinlocks are architecture-defined. So we conservatively require them to be pinned in case
+    /// some architecture uses self-references now or in the future.
+    _pin: PhantomPinned,
+
+    data: UnsafeCell<T>,
+}
+
+// SAFETY: `SpinLock` can be transferred across thread boundaries iff the data it protects can.
+unsafe impl<T: ?Sized + Send> Send for SpinLock<T> {}
+
+// SAFETY: `SpinLock` serialises the interior mutability it provides, so it is `Sync` as long as the
+// data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for SpinLock<T> {}
+
+impl<T> SpinLock<T> {
+    /// Constructs a new spinlock.
+    ///
+    /// # Safety
+    ///
+    /// The caller must call [`SpinLock::init_lock`] before using the spinlock.
+    pub const unsafe fn new(t: T) -> Self {
+        Self {
+            spin_lock: Opaque::uninit(),
+            data: UnsafeCell::new(t),
+            _pin: PhantomPinned,
+        }
+    }
+}
+
+impl<T: ?Sized> SpinLock<T> {
+    /// Locks the spinlock and gives the caller access to the data protected by it. Only one thread
+    /// at a time is allowed to access the protected data.
+    pub fn lock(&self) -> Guard<'_, Self, WriteLock> {
+        let ctx = <Self as Lock<WriteLock>>::lock_noguard(self);
+        // SAFETY: The spinlock was just acquired.
+        unsafe { Guard::new(self, ctx) }
+    }
+
+    /// Locks the spinlock and gives the caller access to the data protected by it. Additionally it
+    /// disables interrupts (if they are enabled).
+    ///
+    /// When the lock in unlocked, the interrupt state (enabled/disabled) is restored.
+    pub fn lock_irqdisable(&self) -> Guard<'_, Self, DisabledInterrupts> {
+        let ctx = <Self as Lock<DisabledInterrupts>>::lock_noguard(self);
+        // SAFETY: The spinlock was just acquired.
+        unsafe { Guard::new(self, ctx) }
+    }
+}
+
+impl<T> LockFactory for SpinLock<T> {
+    type LockedType<U> = SpinLock<U>;
+
+    unsafe fn new_lock<U>(data: U) -> SpinLock<U> {
+        // SAFETY: The safety requirements of `new_lock` also require that `init_lock` be called.
+        unsafe { SpinLock::new(data) }
+    }
+}
+
+impl<T> LockIniter for SpinLock<T> {
+    fn init_lock(self: Pin<&mut Self>, name: &'static CStr, key: &'static LockClassKey) {
+        unsafe { bindings::__spin_lock_init(self.spin_lock.get(), name.as_char_ptr(), key.get()) };
+    }
+}
+
+/// A type state indicating that interrupts were disabled.
+pub struct DisabledInterrupts;
+impl LockInfo for DisabledInterrupts {
+    type Writable = True;
+}
+
+// SAFETY: The underlying kernel `spinlock_t` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock for SpinLock<T> {
+    type Inner = T;
+    type GuardContext = EmptyGuardContext;
+
+    fn lock_noguard(&self) -> EmptyGuardContext {
+        // SAFETY: `spin_lock` points to valid memory.
+        unsafe { bindings::spin_lock(self.spin_lock.get()) };
+        EmptyGuardContext
+    }
+
+    unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+        // SAFETY: The safety requirements of the function ensure that the spinlock is owned by
+        // the caller.
+        unsafe { bindings::spin_unlock(self.spin_lock.get()) }
+    }
+
+    fn locked_data(&self) -> &UnsafeCell<T> {
+        &self.data
+    }
+}
+
+// SAFETY: The underlying kernel `spinlock_t` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock<DisabledInterrupts> for SpinLock<T> {
+    type Inner = T;
+    type GuardContext = core::ffi::c_ulong;
+
+    fn lock_noguard(&self) -> core::ffi::c_ulong {
+        // SAFETY: `spin_lock` points to valid memory.
+        unsafe { bindings::spin_lock_irqsave(self.spin_lock.get()) }
+    }
+
+    unsafe fn unlock(&self, ctx: &mut core::ffi::c_ulong) {
+        // SAFETY: The safety requirements of the function ensure that the spinlock is owned by
+        // the caller.
+        unsafe { bindings::spin_unlock_irqrestore(self.spin_lock.get(), *ctx) }
+    }
+
+    fn locked_data(&self) -> &UnsafeCell<T> {
+        &self.data
+    }
+}
+
+/// Safely initialises a [`RawSpinLock`] with the given name, generating a new lock class.
+#[macro_export]
+macro_rules! rawspinlock_init {
+    ($spinlock:expr, $name:literal) => {
+        $crate::init_with_lockdep!($spinlock, $name)
+    };
+}
+
+/// Exposes the kernel's [`raw_spinlock_t`].
+///
+/// It is very similar to [`SpinLock`], except that it is guaranteed not to sleep even on RT
+/// variants of the kernel.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::sync::RawSpinLock;
+/// # use core::pin::Pin;
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+/// }
+///
+/// // Function that acquires the raw spinlock without changing interrupt state.
+/// fn lock_example(value: &RawSpinLock<Example>) {
+///     let mut guard = value.lock();
+///     guard.a = 10;
+///     guard.b = 20;
+/// }
+///
+/// // Function that acquires the raw spinlock and disables interrupts while holding it.
+/// fn lock_irqdisable_example(value: &RawSpinLock<Example>) {
+///     let mut guard = value.lock_irqdisable();
+///     guard.a = 30;
+///     guard.b = 40;
+/// }
+///
+/// // Initialises a raw spinlock and calls the example functions.
+/// fn spinlock_example() {
+///     // SAFETY: `rawspinlock_init` is called below.
+///     let mut value = unsafe { RawSpinLock::new(Example { a: 1, b: 2 }) };
+///     // SAFETY: We don't move `value`.
+///     kernel::rawspinlock_init!(unsafe { Pin::new_unchecked(&mut value) }, "value");
+///     lock_example(&value);
+///     lock_irqdisable_example(&value);
+/// }
+/// ```
+///
+/// [`raw_spinlock_t`]: ../../../include/linux/spinlock.h
+pub struct RawSpinLock<T: ?Sized> {
+    spin_lock: Opaque<bindings::raw_spinlock>,
+
+    // Spinlocks are architecture-defined. So we conservatively require them to be pinned in case
+    // some architecture uses self-references now or in the future.
+    _pin: PhantomPinned,
+
+    data: UnsafeCell<T>,
+}
+
+// SAFETY: `RawSpinLock` can be transferred across thread boundaries iff the data it protects can.
+unsafe impl<T: ?Sized + Send> Send for RawSpinLock<T> {}
+
+// SAFETY: `RawSpinLock` serialises the interior mutability it provides, so it is `Sync` as long as
+// the data it protects is `Send`.
+unsafe impl<T: ?Sized + Send> Sync for RawSpinLock<T> {}
+
+impl<T> RawSpinLock<T> {
+    /// Constructs a new raw spinlock.
+    ///
+    /// # Safety
+    ///
+    /// The caller must call [`RawSpinLock::init_lock`] before using the raw spinlock.
+    pub const unsafe fn new(t: T) -> Self {
+        Self {
+            spin_lock: Opaque::uninit(),
+            data: UnsafeCell::new(t),
+            _pin: PhantomPinned,
+        }
+    }
+}
+
+impl<T: ?Sized> RawSpinLock<T> {
+    /// Locks the raw spinlock and gives the caller access to the data protected by it. Only one
+    /// thread at a time is allowed to access the protected data.
+    pub fn lock(&self) -> Guard<'_, Self, WriteLock> {
+        let ctx = <Self as Lock<WriteLock>>::lock_noguard(self);
+        // SAFETY: The raw spinlock was just acquired.
+        unsafe { Guard::new(self, ctx) }
+    }
+
+    /// Locks the raw spinlock and gives the caller access to the data protected by it.
+    /// Additionally it disables interrupts (if they are enabled).
+    ///
+    /// When the lock in unlocked, the interrupt state (enabled/disabled) is restored.
+    pub fn lock_irqdisable(&self) -> Guard<'_, Self, DisabledInterrupts> {
+        let ctx = <Self as Lock<DisabledInterrupts>>::lock_noguard(self);
+        // SAFETY: The raw spinlock was just acquired.
+        unsafe { Guard::new(self, ctx) }
+    }
+}
+
+impl<T> LockFactory for RawSpinLock<T> {
+    type LockedType<U> = RawSpinLock<U>;
+
+    unsafe fn new_lock<U>(data: U) -> RawSpinLock<U> {
+        // SAFETY: The safety requirements of `new_lock` also require that `init_lock` be called.
+        unsafe { RawSpinLock::new(data) }
+    }
+}
+
+impl<T> LockIniter for RawSpinLock<T> {
+    fn init_lock(self: Pin<&mut Self>, name: &'static CStr, key: &'static LockClassKey) {
+        unsafe {
+            bindings::_raw_spin_lock_init(self.spin_lock.get(), name.as_char_ptr(), key.get())
+        };
+    }
+}
+
+// SAFETY: The underlying kernel `raw_spinlock_t` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock for RawSpinLock<T> {
+    type Inner = T;
+    type GuardContext = EmptyGuardContext;
+
+    fn lock_noguard(&self) -> EmptyGuardContext {
+        // SAFETY: `spin_lock` points to valid memory.
+        unsafe { bindings::raw_spin_lock(self.spin_lock.get()) };
+        EmptyGuardContext
+    }
+
+    unsafe fn unlock(&self, _: &mut EmptyGuardContext) {
+        // SAFETY: The safety requirements of the function ensure that the raw spinlock is owned by
+        // the caller.
+        unsafe { bindings::raw_spin_unlock(self.spin_lock.get()) };
+    }
+
+    fn locked_data(&self) -> &UnsafeCell<T> {
+        &self.data
+    }
+}
+
+// SAFETY: The underlying kernel `raw_spinlock_t` object ensures mutual exclusion.
+unsafe impl<T: ?Sized> Lock<DisabledInterrupts> for RawSpinLock<T> {
+    type Inner = T;
+    type GuardContext = core::ffi::c_ulong;
+
+    fn lock_noguard(&self) -> core::ffi::c_ulong {
+        // SAFETY: `spin_lock` points to valid memory.
+        unsafe { bindings::raw_spin_lock_irqsave(self.spin_lock.get()) }
+    }
+
+    unsafe fn unlock(&self, ctx: &mut core::ffi::c_ulong) {
+        // SAFETY: The safety requirements of the function ensure that the raw spinlock is owned by
+        // the caller.
+        unsafe { bindings::raw_spin_unlock_irqrestore(self.spin_lock.get(), *ctx) };
+    }
+
+    fn locked_data(&self) -> &UnsafeCell<T> {
+        &self.data
+    }
+}
diff --git a/rust/kernel/sysctl.rs b/rust/kernel/sysctl.rs
new file mode 100644
index 000000000000..8f742d60037d
--- /dev/null
+++ b/rust/kernel/sysctl.rs
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! System control.
+//!
+//! C header: [`include/linux/sysctl.h`](../../../../include/linux/sysctl.h)
+//!
+//! Reference: <https://www.kernel.org/doc/Documentation/sysctl/README>
+
+use alloc::boxed::Box;
+use alloc::vec::Vec;
+use core::mem;
+use core::ptr;
+use core::sync::atomic;
+
+use crate::{
+    bindings,
+    error::code::*,
+    io_buffer::IoBufferWriter,
+    str::CStr,
+    types,
+    user_ptr::{UserSlicePtr, UserSlicePtrWriter},
+    Result,
+};
+
+/// Sysctl storage.
+pub trait SysctlStorage: Sync {
+    /// Writes a byte slice.
+    fn store_value(&self, data: &[u8]) -> (usize, Result);
+
+    /// Reads via a [`UserSlicePtrWriter`].
+    fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, Result);
+}
+
+fn trim_whitespace(mut data: &[u8]) -> &[u8] {
+    while !data.is_empty() && (data[0] == b' ' || data[0] == b'\t' || data[0] == b'\n') {
+        data = &data[1..];
+    }
+    while !data.is_empty()
+        && (data[data.len() - 1] == b' '
+            || data[data.len() - 1] == b'\t'
+            || data[data.len() - 1] == b'\n')
+    {
+        data = &data[..data.len() - 1];
+    }
+    data
+}
+
+impl<T> SysctlStorage for &T
+where
+    T: SysctlStorage,
+{
+    fn store_value(&self, data: &[u8]) -> (usize, Result) {
+        (*self).store_value(data)
+    }
+
+    fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, Result) {
+        (*self).read_value(data)
+    }
+}
+
+impl SysctlStorage for atomic::AtomicBool {
+    fn store_value(&self, data: &[u8]) -> (usize, Result) {
+        let result = match trim_whitespace(data) {
+            b"0" => {
+                self.store(false, atomic::Ordering::Relaxed);
+                Ok(())
+            }
+            b"1" => {
+                self.store(true, atomic::Ordering::Relaxed);
+                Ok(())
+            }
+            _ => Err(EINVAL),
+        };
+        (data.len(), result)
+    }
+
+    fn read_value(&self, data: &mut UserSlicePtrWriter) -> (usize, Result) {
+        let value = if self.load(atomic::Ordering::Relaxed) {
+            b"1\n"
+        } else {
+            b"0\n"
+        };
+        (value.len(), data.write_slice(value))
+    }
+}
+
+/// Holds a single `sysctl` entry (and its table).
+pub struct Sysctl<T: SysctlStorage> {
+    inner: Box<T>,
+    // Responsible for keeping the `ctl_table` alive.
+    _table: Box<[bindings::ctl_table]>,
+    header: *mut bindings::ctl_table_header,
+}
+
+// SAFETY: The only public method we have is `get()`, which returns `&T`, and
+// `T: Sync`. Any new methods must adhere to this requirement.
+unsafe impl<T: SysctlStorage> Sync for Sysctl<T> {}
+
+unsafe extern "C" fn proc_handler<T: SysctlStorage>(
+    ctl: *mut bindings::ctl_table,
+    write: core::ffi::c_int,
+    buffer: *mut core::ffi::c_void,
+    len: *mut usize,
+    ppos: *mut bindings::loff_t,
+) -> core::ffi::c_int {
+    // If we are reading from some offset other than the beginning of the file,
+    // return an empty read to signal EOF.
+    if unsafe { *ppos } != 0 && write == 0 {
+        unsafe { *len = 0 };
+        return 0;
+    }
+
+    let data = unsafe { UserSlicePtr::new(buffer, *len) };
+    let storage = unsafe { &*((*ctl).data as *const T) };
+    let (bytes_processed, result) = if write != 0 {
+        let data = match data.read_all() {
+            Ok(r) => r,
+            Err(e) => return e.to_kernel_errno(),
+        };
+        storage.store_value(&data)
+    } else {
+        let mut writer = data.writer();
+        storage.read_value(&mut writer)
+    };
+    unsafe { *len = bytes_processed };
+    unsafe { *ppos += *len as bindings::loff_t };
+    match result {
+        Ok(()) => 0,
+        Err(e) => e.to_kernel_errno(),
+    }
+}
+
+impl<T: SysctlStorage> Sysctl<T> {
+    /// Registers a single entry in `sysctl`.
+    pub fn register(
+        path: &'static CStr,
+        name: &'static CStr,
+        storage: T,
+        mode: types::Mode,
+    ) -> Result<Sysctl<T>> {
+        if name.contains(&b'/') {
+            return Err(EINVAL);
+        }
+
+        let storage = Box::try_new(storage)?;
+        let mut table = Vec::try_with_capacity(2)?;
+        table.try_push(bindings::ctl_table {
+            procname: name.as_char_ptr(),
+            mode: mode.as_int(),
+            data: &*storage as *const T as *mut core::ffi::c_void,
+            proc_handler: Some(proc_handler::<T>),
+
+            maxlen: 0,
+            child: ptr::null_mut(),
+            poll: ptr::null_mut(),
+            extra1: ptr::null_mut(),
+            extra2: ptr::null_mut(),
+        })?;
+        table.try_push(unsafe { mem::zeroed() })?;
+        let mut table = table.try_into_boxed_slice()?;
+
+        let result = unsafe { bindings::register_sysctl(path.as_char_ptr(), table.as_mut_ptr()) };
+        if result.is_null() {
+            return Err(ENOMEM);
+        }
+
+        Ok(Sysctl {
+            inner: storage,
+            _table: table,
+            header: result,
+        })
+    }
+
+    /// Gets the storage.
+    pub fn get(&self) -> &T {
+        &self.inner
+    }
+}
+
+impl<T: SysctlStorage> Drop for Sysctl<T> {
+    fn drop(&mut self) {
+        unsafe {
+            bindings::unregister_sysctl_table(self.header);
+        }
+        self.header = ptr::null_mut();
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_trim_whitespace() {
+        assert_eq!(trim_whitespace(b"foo    "), b"foo");
+        assert_eq!(trim_whitespace(b"    foo"), b"foo");
+        assert_eq!(trim_whitespace(b"  foo  "), b"foo");
+    }
+}
diff --git a/rust/kernel/task.rs b/rust/kernel/task.rs
new file mode 100644
index 000000000000..67040b532816
--- /dev/null
+++ b/rust/kernel/task.rs
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Tasks (threads and processes).
+//!
+//! C header: [`include/linux/sched.h`](../../../../include/linux/sched.h).
+
+use crate::{
+    bindings, c_str, error::from_kernel_err_ptr, types::PointerWrapper, ARef, AlwaysRefCounted,
+    Result, ScopeGuard,
+};
+use alloc::boxed::Box;
+use core::{cell::UnsafeCell, fmt, marker::PhantomData, ops::Deref, ptr};
+
+/// Wraps the kernel's `struct task_struct`.
+///
+/// # Invariants
+///
+/// Instances of this type are always ref-counted, that is, a call to `get_task_struct` ensures
+/// that the allocation remains valid at least until the matching call to `put_task_struct`.
+///
+/// # Examples
+///
+/// The following is an example of getting the PID of the current thread with zero additional cost
+/// when compared to the C version:
+///
+/// ```
+/// use kernel::task::Task;
+///
+/// let pid = Task::current().pid();
+/// ```
+///
+/// Getting the PID of the current process, also zero additional cost:
+///
+/// ```
+/// use kernel::task::Task;
+///
+/// let pid = Task::current().group_leader().pid();
+/// ```
+///
+/// Getting the current task and storing it in some struct. The reference count is automatically
+/// incremented when creating `State` and decremented when it is dropped:
+///
+/// ```
+/// use kernel::{task::Task, ARef};
+///
+/// struct State {
+///     creator: ARef<Task>,
+///     index: u32,
+/// }
+///
+/// impl State {
+///     fn new() -> Self {
+///         Self {
+///             creator: Task::current().into(),
+///             index: 0,
+///         }
+///     }
+/// }
+/// ```
+#[repr(transparent)]
+pub struct Task(pub(crate) UnsafeCell<bindings::task_struct>);
+
+// SAFETY: It's OK to access `Task` through references from other threads because we're either
+// accessing properties that don't change (e.g., `pid`, `group_leader`) or that are properly
+// synchronised by C code (e.g., `signal_pending`).
+unsafe impl Sync for Task {}
+
+/// The type of process identifiers (PIDs).
+type Pid = bindings::pid_t;
+
+impl Task {
+    /// Returns a task reference for the currently executing task/thread.
+    pub fn current<'a>() -> TaskRef<'a> {
+        // SAFETY: Just an FFI call.
+        let ptr = unsafe { bindings::get_current() };
+
+        TaskRef {
+            // SAFETY: If the current thread is still running, the current task is valid. Given
+            // that `TaskRef` is not `Send`, we know it cannot be transferred to another thread
+            // (where it could potentially outlive the caller).
+            task: unsafe { &*ptr.cast() },
+            _not_send: PhantomData,
+        }
+    }
+
+    /// Returns the group leader of the given task.
+    pub fn group_leader(&self) -> &Task {
+        // SAFETY: By the type invariant, we know that `self.0` is valid.
+        let ptr = unsafe { core::ptr::addr_of!((*self.0.get()).group_leader).read() };
+
+        // SAFETY: The lifetime of the returned task reference is tied to the lifetime of `self`,
+        // and given that a task has a reference to its group leader, we know it must be valid for
+        // the lifetime of the returned task reference.
+        unsafe { &*ptr.cast() }
+    }
+
+    /// Returns the PID of the given task.
+    pub fn pid(&self) -> Pid {
+        // SAFETY: By the type invariant, we know that `self.0` is valid.
+        unsafe { core::ptr::addr_of!((*self.0.get()).pid).read() }
+    }
+
+    /// Determines whether the given task has pending signals.
+    pub fn signal_pending(&self) -> bool {
+        // SAFETY: By the type invariant, we know that `self.0` is valid.
+        unsafe { bindings::signal_pending(self.0.get()) != 0 }
+    }
+
+    /// Starts a new kernel thread and runs it.
+    ///
+    /// # Examples
+    ///
+    /// Launches 10 threads and waits for them to complete.
+    ///
+    /// ```
+    /// use core::sync::atomic::{AtomicU32, Ordering};
+    /// use kernel::sync::{CondVar, Mutex};
+    /// use kernel::task::Task;
+    ///
+    /// kernel::init_static_sync! {
+    ///     static COUNT: Mutex<u32> = 0;
+    ///     static COUNT_IS_ZERO: CondVar;
+    /// }
+    ///
+    /// fn threadfn() {
+    ///     pr_info!("Running from thread {}\n", Task::current().pid());
+    ///     let mut guard = COUNT.lock();
+    ///     *guard -= 1;
+    ///     if *guard == 0 {
+    ///         COUNT_IS_ZERO.notify_all();
+    ///     }
+    /// }
+    ///
+    /// // Set count to 10 and spawn 10 threads.
+    /// *COUNT.lock() = 10;
+    /// for i in 0..10 {
+    ///     Task::spawn(fmt!("test{i}"), threadfn).unwrap();
+    /// }
+    ///
+    /// // Wait for count to drop to zero.
+    /// let mut guard = COUNT.lock();
+    /// while (*guard != 0) {
+    ///     COUNT_IS_ZERO.wait(&mut guard);
+    /// }
+    /// ```
+    pub fn spawn<T: FnOnce() + Send + 'static>(
+        name: fmt::Arguments<'_>,
+        func: T,
+    ) -> Result<ARef<Task>> {
+        unsafe extern "C" fn threadfn<T: FnOnce() + Send + 'static>(
+            arg: *mut core::ffi::c_void,
+        ) -> core::ffi::c_int {
+            // SAFETY: The thread argument is always a `Box<T>` because it is only called via the
+            // thread creation below.
+            let bfunc = unsafe { Box::<T>::from_pointer(arg) };
+            bfunc();
+            0
+        }
+
+        let arg = Box::try_new(func)?.into_pointer();
+
+        // SAFETY: `arg` was just created with a call to `into_pointer` above.
+        let guard = ScopeGuard::new(|| unsafe {
+            Box::<T>::from_pointer(arg);
+        });
+
+        // SAFETY: The function pointer is always valid (as long as the module remains loaded).
+        // Ownership of `raw` is transferred to the new thread (if one is actually created), so it
+        // remains valid. Lastly, the C format string is a constant that require formatting as the
+        // one and only extra argument.
+        let ktask = from_kernel_err_ptr(unsafe {
+            bindings::kthread_create_on_node(
+                Some(threadfn::<T>),
+                arg as _,
+                bindings::NUMA_NO_NODE,
+                c_str!("%pA").as_char_ptr(),
+                &name as *const _ as *const core::ffi::c_void,
+            )
+        })?;
+
+        // SAFETY: Since the kthread creation succeeded and we haven't run it yet, we know the task
+        // is valid.
+        let task: ARef<_> = unsafe { &*(ktask as *const Task) }.into();
+
+        // Wakes up the thread, otherwise it won't run.
+        task.wake_up();
+
+        guard.dismiss();
+        Ok(task)
+    }
+
+    /// Wakes up the task.
+    pub fn wake_up(&self) {
+        // SAFETY: By the type invariant, we know that `self.0.get()` is non-null and valid.
+        // And `wake_up_process` is safe to be called for any valid task, even if the task is
+        // running.
+        unsafe { bindings::wake_up_process(self.0.get()) };
+    }
+}
+
+// SAFETY: The type invariants guarantee that `Task` is always ref-counted.
+unsafe impl AlwaysRefCounted for Task {
+    fn inc_ref(&self) {
+        // SAFETY: The existence of a shared reference means that the refcount is nonzero.
+        unsafe { bindings::get_task_struct(self.0.get()) };
+    }
+
+    unsafe fn dec_ref(obj: ptr::NonNull<Self>) {
+        // SAFETY: The safety requirements guarantee that the refcount is nonzero.
+        unsafe { bindings::put_task_struct(obj.cast().as_ptr()) }
+    }
+}
+
+/// A wrapper for a shared reference to [`Task`] that isn't [`Send`].
+///
+/// We make this explicitly not [`Send`] so that we can use it to represent the current thread
+/// without having to increment/decrement the task's reference count.
+///
+/// # Invariants
+///
+/// The wrapped [`Task`] remains valid for the lifetime of the object.
+pub struct TaskRef<'a> {
+    task: &'a Task,
+    _not_send: PhantomData<*mut ()>,
+}
+
+impl Deref for TaskRef<'_> {
+    type Target = Task;
+
+    fn deref(&self) -> &Self::Target {
+        self.task
+    }
+}
+
+impl From<TaskRef<'_>> for ARef<Task> {
+    fn from(t: TaskRef<'_>) -> Self {
+        t.deref().into()
+    }
+}
diff --git a/rust/kernel/types.rs b/rust/kernel/types.rs
new file mode 100644
index 000000000000..b1f73aeece0b
--- /dev/null
+++ b/rust/kernel/types.rs
@@ -0,0 +1,705 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Kernel types.
+//!
+//! C header: [`include/linux/types.h`](../../../../include/linux/types.h)
+
+use crate::{
+    bindings,
+    sync::{Ref, RefBorrow},
+};
+use alloc::boxed::Box;
+use core::{
+    cell::UnsafeCell,
+    marker::PhantomData,
+    mem::MaybeUninit,
+    ops::{self, Deref, DerefMut},
+    pin::Pin,
+    ptr::NonNull,
+};
+
+/// Permissions.
+///
+/// C header: [`include/uapi/linux/stat.h`](../../../../include/uapi/linux/stat.h)
+///
+/// C header: [`include/linux/stat.h`](../../../../include/linux/stat.h)
+pub struct Mode(bindings::umode_t);
+
+impl Mode {
+    /// Creates a [`Mode`] from an integer.
+    pub fn from_int(m: u16) -> Mode {
+        Mode(m)
+    }
+
+    /// Returns the mode as an integer.
+    pub fn as_int(&self) -> u16 {
+        self.0
+    }
+}
+
+/// Used to convert an object into a raw pointer that represents it.
+///
+/// It can eventually be converted back into the object. This is used to store objects as pointers
+/// in kernel data structures, for example, an implementation of
+/// [`Operations`][crate::file::Operations] in `struct
+/// file::private_data`.
+pub trait PointerWrapper {
+    /// Type of values borrowed between calls to [`PointerWrapper::into_pointer`] and
+    /// [`PointerWrapper::from_pointer`].
+    type Borrowed<'a>;
+
+    /// Returns the raw pointer.
+    fn into_pointer(self) -> *const core::ffi::c_void;
+
+    /// Returns a borrowed value.
+    ///
+    /// # Safety
+    ///
+    /// `ptr` must have been returned by a previous call to [`PointerWrapper::into_pointer`].
+    /// Additionally, [`PointerWrapper::from_pointer`] can only be called after *all* values
+    /// returned by [`PointerWrapper::borrow`] have been dropped.
+    unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Self::Borrowed<'a>;
+
+    /// Returns a mutably borrowed value.
+    ///
+    /// # Safety
+    ///
+    /// The passed pointer must come from a previous to [`PointerWrapper::into_pointer`], and no
+    /// other concurrent users of the pointer (except the ones derived from the returned value) run
+    /// at least until the returned [`ScopeGuard`] is dropped.
+    unsafe fn borrow_mut<T: PointerWrapper>(ptr: *const core::ffi::c_void) -> ScopeGuard<T, fn(T)> {
+        // SAFETY: The safety requirements ensure that `ptr` came from a previous call to
+        // `into_pointer`.
+        ScopeGuard::new_with_data(unsafe { T::from_pointer(ptr) }, |d| {
+            d.into_pointer();
+        })
+    }
+
+    /// Returns the instance back from the raw pointer.
+    ///
+    /// # Safety
+    ///
+    /// The passed pointer must come from a previous call to [`PointerWrapper::into_pointer()`].
+    unsafe fn from_pointer(ptr: *const core::ffi::c_void) -> Self;
+}
+
+impl<T: 'static> PointerWrapper for Box<T> {
+    type Borrowed<'a> = &'a T;
+
+    fn into_pointer(self) -> *const core::ffi::c_void {
+        Box::into_raw(self) as _
+    }
+
+    unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> &'a T {
+        // SAFETY: The safety requirements for this function ensure that the object is still alive,
+        // so it is safe to dereference the raw pointer.
+        // The safety requirements also ensure that the object remains alive for the lifetime of
+        // the returned value.
+        unsafe { &*ptr.cast() }
+    }
+
+    unsafe fn from_pointer(ptr: *const core::ffi::c_void) -> Self {
+        // SAFETY: The passed pointer comes from a previous call to [`Self::into_pointer()`].
+        unsafe { Box::from_raw(ptr as _) }
+    }
+}
+
+impl<T: 'static> PointerWrapper for Ref<T> {
+    type Borrowed<'a> = RefBorrow<'a, T>;
+
+    fn into_pointer(self) -> *const core::ffi::c_void {
+        Ref::into_usize(self) as _
+    }
+
+    unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> RefBorrow<'a, T> {
+        // SAFETY: The safety requirements for this function ensure that the underlying object
+        // remains valid for the lifetime of the returned value.
+        unsafe { Ref::borrow_usize(ptr as _) }
+    }
+
+    unsafe fn from_pointer(ptr: *const core::ffi::c_void) -> Self {
+        // SAFETY: The passed pointer comes from a previous call to [`Self::into_pointer()`].
+        unsafe { Ref::from_usize(ptr as _) }
+    }
+}
+
+impl<T: PointerWrapper + Deref> PointerWrapper for Pin<T> {
+    type Borrowed<'a> = T::Borrowed<'a>;
+
+    fn into_pointer(self) -> *const core::ffi::c_void {
+        // SAFETY: We continue to treat the pointer as pinned by returning just a pointer to it to
+        // the caller.
+        let inner = unsafe { Pin::into_inner_unchecked(self) };
+        inner.into_pointer()
+    }
+
+    unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Self::Borrowed<'a> {
+        // SAFETY: The safety requirements for this function are the same as the ones for
+        // `T::borrow`.
+        unsafe { T::borrow(ptr) }
+    }
+
+    unsafe fn from_pointer(p: *const core::ffi::c_void) -> Self {
+        // SAFETY: The object was originally pinned.
+        // The passed pointer comes from a previous call to `inner::into_pointer()`.
+        unsafe { Pin::new_unchecked(T::from_pointer(p)) }
+    }
+}
+
+impl<T> PointerWrapper for *mut T {
+    type Borrowed<'a> = *mut T;
+
+    fn into_pointer(self) -> *const core::ffi::c_void {
+        self as _
+    }
+
+    unsafe fn borrow<'a>(ptr: *const core::ffi::c_void) -> Self::Borrowed<'a> {
+        ptr as _
+    }
+
+    unsafe fn from_pointer(ptr: *const core::ffi::c_void) -> Self {
+        ptr as _
+    }
+}
+
+impl PointerWrapper for () {
+    type Borrowed<'a> = ();
+
+    fn into_pointer(self) -> *const core::ffi::c_void {
+        // We use 1 to be different from a null pointer.
+        1usize as _
+    }
+
+    unsafe fn borrow<'a>(_: *const core::ffi::c_void) -> Self::Borrowed<'a> {}
+
+    unsafe fn from_pointer(_: *const core::ffi::c_void) -> Self {}
+}
+
+/// Runs a cleanup function/closure when dropped.
+///
+/// The [`ScopeGuard::dismiss`] function prevents the cleanup function from running.
+///
+/// # Examples
+///
+/// In the example below, we have multiple exit paths and we want to log regardless of which one is
+/// taken:
+/// ```
+/// # use kernel::ScopeGuard;
+/// fn example1(arg: bool) {
+///     let _log = ScopeGuard::new(|| pr_info!("example1 completed\n"));
+///
+///     if arg {
+///         return;
+///     }
+///
+///     pr_info!("Do something...\n");
+/// }
+///
+/// # example1(false);
+/// # example1(true);
+/// ```
+///
+/// In the example below, we want to log the same message on all early exits but a different one on
+/// the main exit path:
+/// ```
+/// # use kernel::ScopeGuard;
+/// fn example2(arg: bool) {
+///     let log = ScopeGuard::new(|| pr_info!("example2 returned early\n"));
+///
+///     if arg {
+///         return;
+///     }
+///
+///     // (Other early returns...)
+///
+///     log.dismiss();
+///     pr_info!("example2 no early return\n");
+/// }
+///
+/// # example2(false);
+/// # example2(true);
+/// ```
+///
+/// In the example below, we need a mutable object (the vector) to be accessible within the log
+/// function, so we wrap it in the [`ScopeGuard`]:
+/// ```
+/// # use kernel::ScopeGuard;
+/// fn example3(arg: bool) -> Result {
+///     let mut vec =
+///         ScopeGuard::new_with_data(Vec::new(), |v| pr_info!("vec had {} elements\n", v.len()));
+///
+///     vec.try_push(10u8)?;
+///     if arg {
+///         return Ok(());
+///     }
+///     vec.try_push(20u8)?;
+///     Ok(())
+/// }
+///
+/// # assert_eq!(example3(false), Ok(()));
+/// # assert_eq!(example3(true), Ok(()));
+/// ```
+///
+/// # Invariants
+///
+/// The value stored in the struct is nearly always `Some(_)`, except between
+/// [`ScopeGuard::dismiss`] and [`ScopeGuard::drop`]: in this case, it will be `None` as the value
+/// will have been returned to the caller. Since  [`ScopeGuard::dismiss`] consumes the guard,
+/// callers won't be able to use it anymore.
+pub struct ScopeGuard<T, F: FnOnce(T)>(Option<(T, F)>);
+
+impl<T, F: FnOnce(T)> ScopeGuard<T, F> {
+    /// Creates a new guarded object wrapping the given data and with the given cleanup function.
+    pub fn new_with_data(data: T, cleanup_func: F) -> Self {
+        // INVARIANT: The struct is being initialised with `Some(_)`.
+        Self(Some((data, cleanup_func)))
+    }
+
+    /// Prevents the cleanup function from running and returns the guarded data.
+    pub fn dismiss(mut self) -> T {
+        // INVARIANT: This is the exception case in the invariant; it is not visible to callers
+        // because this function consumes `self`.
+        self.0.take().unwrap().0
+    }
+}
+
+impl ScopeGuard<(), Box<dyn FnOnce(())>> {
+    /// Creates a new guarded object with the given cleanup function.
+    pub fn new(cleanup: impl FnOnce()) -> ScopeGuard<(), impl FnOnce(())> {
+        ScopeGuard::new_with_data((), move |_| cleanup())
+    }
+}
+
+impl<T, F: FnOnce(T)> Deref for ScopeGuard<T, F> {
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        // The type invariants guarantee that `unwrap` will succeed.
+        &self.0.as_ref().unwrap().0
+    }
+}
+
+impl<T, F: FnOnce(T)> DerefMut for ScopeGuard<T, F> {
+    fn deref_mut(&mut self) -> &mut T {
+        // The type invariants guarantee that `unwrap` will succeed.
+        &mut self.0.as_mut().unwrap().0
+    }
+}
+
+impl<T, F: FnOnce(T)> Drop for ScopeGuard<T, F> {
+    fn drop(&mut self) {
+        // Run the cleanup function if one is still present.
+        if let Some((data, cleanup)) = self.0.take() {
+            cleanup(data)
+        }
+    }
+}
+
+/// Stores an opaque value.
+///
+/// This is meant to be used with FFI objects that are never interpreted by Rust code.
+#[repr(transparent)]
+pub struct Opaque<T>(MaybeUninit<UnsafeCell<T>>);
+
+impl<T> Opaque<T> {
+    /// Creates a new opaque value.
+    pub const fn new(value: T) -> Self {
+        Self(MaybeUninit::new(UnsafeCell::new(value)))
+    }
+
+    /// Creates an uninitialised value.
+    pub const fn uninit() -> Self {
+        Self(MaybeUninit::uninit())
+    }
+
+    /// Returns a raw pointer to the opaque data.
+    pub fn get(&self) -> *mut T {
+        UnsafeCell::raw_get(self.0.as_ptr())
+    }
+}
+
+/// A bitmask.
+///
+/// It has a restriction that all bits must be the same, except one. For example, `0b1110111` and
+/// `0b1000` are acceptable masks.
+#[derive(Clone, Copy)]
+pub struct Bit<T> {
+    index: T,
+    inverted: bool,
+}
+
+/// Creates a bit mask with a single bit set.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::bit;
+/// let mut x = 0xfeu32;
+///
+/// assert_eq!(x & bit(0), 0);
+/// assert_eq!(x & bit(1), 2);
+/// assert_eq!(x & bit(2), 4);
+/// assert_eq!(x & bit(3), 8);
+///
+/// x |= bit(0);
+/// assert_eq!(x, 0xff);
+///
+/// x &= !bit(1);
+/// assert_eq!(x, 0xfd);
+///
+/// x &= !bit(7);
+/// assert_eq!(x, 0x7d);
+///
+/// let y: u64 = bit(34).into();
+/// assert_eq!(y, 0x400000000);
+///
+/// assert_eq!(y | bit(35), 0xc00000000);
+/// ```
+pub fn bit<T: Copy>(index: T) -> Bit<T> {
+    Bit {
+        index,
+        inverted: false,
+    }
+}
+
+impl<T: Copy> ops::Not for Bit<T> {
+    type Output = Self;
+    fn not(self) -> Self {
+        Self {
+            index: self.index,
+            inverted: !self.inverted,
+        }
+    }
+}
+
+/// Implemented by integer types that allow counting the number of trailing zeroes.
+pub trait TrailingZeros {
+    /// Returns the number of trailing zeroes in the binary representation of `self`.
+    fn trailing_zeros(&self) -> u32;
+}
+
+macro_rules! define_unsigned_number_traits {
+    ($type_name:ty) => {
+        impl TrailingZeros for $type_name {
+            fn trailing_zeros(&self) -> u32 {
+                <$type_name>::trailing_zeros(*self)
+            }
+        }
+
+        impl<T: Copy> core::convert::From<Bit<T>> for $type_name
+        where
+            Self: ops::Shl<T, Output = Self> + core::convert::From<u8> + ops::Not<Output = Self>,
+        {
+            fn from(v: Bit<T>) -> Self {
+                let c = Self::from(1u8) << v.index;
+                if v.inverted {
+                    !c
+                } else {
+                    c
+                }
+            }
+        }
+
+        impl<T: Copy> ops::BitAnd<Bit<T>> for $type_name
+        where
+            Self: ops::Shl<T, Output = Self> + core::convert::From<u8>,
+        {
+            type Output = Self;
+            fn bitand(self, rhs: Bit<T>) -> Self::Output {
+                self & Self::from(rhs)
+            }
+        }
+
+        impl<T: Copy> ops::BitOr<Bit<T>> for $type_name
+        where
+            Self: ops::Shl<T, Output = Self> + core::convert::From<u8>,
+        {
+            type Output = Self;
+            fn bitor(self, rhs: Bit<T>) -> Self::Output {
+                self | Self::from(rhs)
+            }
+        }
+
+        impl<T: Copy> ops::BitAndAssign<Bit<T>> for $type_name
+        where
+            Self: ops::Shl<T, Output = Self> + core::convert::From<u8>,
+        {
+            fn bitand_assign(&mut self, rhs: Bit<T>) {
+                *self &= Self::from(rhs)
+            }
+        }
+
+        impl<T: Copy> ops::BitOrAssign<Bit<T>> for $type_name
+        where
+            Self: ops::Shl<T, Output = Self> + core::convert::From<u8>,
+        {
+            fn bitor_assign(&mut self, rhs: Bit<T>) {
+                *self |= Self::from(rhs)
+            }
+        }
+    };
+}
+
+define_unsigned_number_traits!(u8);
+define_unsigned_number_traits!(u16);
+define_unsigned_number_traits!(u32);
+define_unsigned_number_traits!(u64);
+define_unsigned_number_traits!(usize);
+
+/// Returns an iterator over the set bits of `value`.
+///
+/// # Examples
+///
+/// ```
+/// use kernel::bits_iter;
+///
+/// let mut iter = bits_iter(5usize);
+/// assert_eq!(iter.next().unwrap(), 0);
+/// assert_eq!(iter.next().unwrap(), 2);
+/// assert!(iter.next().is_none());
+/// ```
+///
+/// ```
+/// use kernel::bits_iter;
+///
+/// fn print_bits(x: usize) {
+///     for bit in bits_iter(x) {
+///         pr_info!("{}\n", bit);
+///     }
+/// }
+///
+/// # print_bits(42);
+/// ```
+#[inline]
+pub fn bits_iter<T>(value: T) -> impl Iterator<Item = u32>
+where
+    T: core::cmp::PartialEq
+        + From<u8>
+        + ops::Shl<u32, Output = T>
+        + ops::Not<Output = T>
+        + ops::BitAndAssign
+        + TrailingZeros,
+{
+    struct BitIterator<U> {
+        value: U,
+    }
+
+    impl<U> Iterator for BitIterator<U>
+    where
+        U: core::cmp::PartialEq
+            + From<u8>
+            + ops::Shl<u32, Output = U>
+            + ops::Not<Output = U>
+            + ops::BitAndAssign
+            + TrailingZeros,
+    {
+        type Item = u32;
+
+        #[inline]
+        fn next(&mut self) -> Option<u32> {
+            if self.value == U::from(0u8) {
+                return None;
+            }
+            let ret = self.value.trailing_zeros();
+            self.value &= !(U::from(1u8) << ret);
+            Some(ret)
+        }
+    }
+
+    BitIterator { value }
+}
+
+/// A trait for boolean types.
+///
+/// This is meant to be used in type states to allow boolean constraints in implementation blocks.
+/// In the example below, the implementation containing `MyType::set_value` could _not_ be
+/// constrained to type states containing `Writable = true` if `Writable` were a constant instead
+/// of a type.
+///
+/// # Safety
+///
+/// No additional implementations of [`Bool`] should be provided, as [`True`] and [`False`] are
+/// already provided.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::{Bool, False, True};
+/// use core::marker::PhantomData;
+///
+/// // Type state specifies whether the type is writable.
+/// trait MyTypeState {
+///     type Writable: Bool;
+/// }
+///
+/// // In state S1, the type is writable.
+/// struct S1;
+/// impl MyTypeState for S1 {
+///     type Writable = True;
+/// }
+///
+/// // In state S2, the type is not writable.
+/// struct S2;
+/// impl MyTypeState for S2 {
+///     type Writable = False;
+/// }
+///
+/// struct MyType<T: MyTypeState> {
+///     value: u32,
+///     _p: PhantomData<T>,
+/// }
+///
+/// impl<T: MyTypeState> MyType<T> {
+///     fn new(value: u32) -> Self {
+///         Self {
+///             value,
+///             _p: PhantomData,
+///         }
+///     }
+/// }
+///
+/// // This implementation block only applies if the type state is writable.
+/// impl<T> MyType<T>
+/// where
+///     T: MyTypeState<Writable = True>,
+/// {
+///     fn set_value(&mut self, v: u32) {
+///         self.value = v;
+///     }
+/// }
+///
+/// let mut x = MyType::<S1>::new(10);
+/// let mut y = MyType::<S2>::new(20);
+///
+/// x.set_value(30);
+///
+/// // The code below fails to compile because `S2` is not writable.
+/// // y.set_value(40);
+/// ```
+pub unsafe trait Bool {}
+
+/// Represents the `true` value for types with [`Bool`] bound.
+pub struct True;
+
+// SAFETY: This is one of the only two implementations of `Bool`.
+unsafe impl Bool for True {}
+
+/// Represents the `false` value for types wth [`Bool`] bound.
+pub struct False;
+
+// SAFETY: This is one of the only two implementations of `Bool`.
+unsafe impl Bool for False {}
+
+/// Types that are _always_ reference counted.
+///
+/// It allows such types to define their own custom ref increment and decrement functions.
+/// Additionally, it allows users to convert from a shared reference `&T` to an owned reference
+/// [`ARef<T>`].
+///
+/// This is usually implemented by wrappers to existing structures on the C side of the code. For
+/// Rust code, the recommendation is to use [`Ref`] to create reference-counted instances of a
+/// type.
+///
+/// # Safety
+///
+/// Implementers must ensure that increments to the reference count keeps the object alive in
+/// memory at least until a matching decrement performed.
+///
+/// Implementers must also ensure that all instances are reference-counted. (Otherwise they
+/// won't be able to honour the requirement that [`AlwaysRefCounted::inc_ref`] keep the object
+/// alive.)
+pub unsafe trait AlwaysRefCounted {
+    /// Increments the reference count on the object.
+    fn inc_ref(&self);
+
+    /// Decrements the reference count on the object.
+    ///
+    /// Frees the object when the count reaches zero.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that there was a previous matching increment to the reference count,
+    /// and that the object is no longer used after its reference count is decremented (as it may
+    /// result in the object being freed), unless the caller owns another increment on the refcount
+    /// (e.g., it calls [`AlwaysRefCounted::inc_ref`] twice, then calls
+    /// [`AlwaysRefCounted::dec_ref`] once).
+    unsafe fn dec_ref(obj: NonNull<Self>);
+}
+
+/// An owned reference to an always-reference-counted object.
+///
+/// The object's reference count is automatically decremented when an instance of [`ARef`] is
+/// dropped. It is also automatically incremented when a new instance is created via
+/// [`ARef::clone`].
+///
+/// # Invariants
+///
+/// The pointer stored in `ptr` is non-null and valid for the lifetime of the [`ARef`] instance. In
+/// particular, the [`ARef`] instance owns an increment on underlying object's reference count.
+pub struct ARef<T: AlwaysRefCounted> {
+    ptr: NonNull<T>,
+    _p: PhantomData<T>,
+}
+
+impl<T: AlwaysRefCounted> ARef<T> {
+    /// Creates a new instance of [`ARef`].
+    ///
+    /// It takes over an increment of the reference count on the underlying object.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that the reference count was incremented at least once, and that they
+    /// are properly relinquishing one increment. That is, if there is only one increment, callers
+    /// must not use the underlying object anymore -- it is only safe to do so via the newly
+    /// created [`ARef`].
+    pub unsafe fn from_raw(ptr: NonNull<T>) -> Self {
+        // INVARIANT: The safety requirements guarantee that the new instance now owns the
+        // increment on the refcount.
+        Self {
+            ptr,
+            _p: PhantomData,
+        }
+    }
+}
+
+impl<T: AlwaysRefCounted> Clone for ARef<T> {
+    fn clone(&self) -> Self {
+        self.inc_ref();
+        // SAFETY: We just incremented the refcount above.
+        unsafe { Self::from_raw(self.ptr) }
+    }
+}
+
+impl<T: AlwaysRefCounted> Deref for ARef<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: The type invariants guarantee that the object is valid.
+        unsafe { self.ptr.as_ref() }
+    }
+}
+
+impl<T: AlwaysRefCounted> From<&T> for ARef<T> {
+    fn from(b: &T) -> Self {
+        b.inc_ref();
+        // SAFETY: We just incremented the refcount above.
+        unsafe { Self::from_raw(NonNull::from(b)) }
+    }
+}
+
+impl<T: AlwaysRefCounted> Drop for ARef<T> {
+    fn drop(&mut self) {
+        // SAFETY: The type invariants guarantee that the `ARef` owns the reference we're about to
+        // decrement.
+        unsafe { T::dec_ref(self.ptr) };
+    }
+}
+
+/// A sum type that always holds either a value of type `L` or `R`.
+pub enum Either<L, R> {
+    /// Constructs an instance of [`Either`] containing a value of type `L`.
+    Left(L),
+
+    /// Constructs an instance of [`Either`] containing a value of type `R`.
+    Right(R),
+}
diff --git a/rust/kernel/unsafe_list.rs b/rust/kernel/unsafe_list.rs
new file mode 100644
index 000000000000..df496667c033
--- /dev/null
+++ b/rust/kernel/unsafe_list.rs
@@ -0,0 +1,680 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Intrusive circular doubly-linked lists.
+//!
+//! We don't use the C version for two main reasons:
+//! - Next/prev pointers do not support `?Sized` types, so wouldn't be able to have a list of, for
+//!   example, `dyn Trait`.
+//! - It would require the list head to be pinned (in addition to the list entries).
+
+use core::{cell::UnsafeCell, iter, marker::PhantomPinned, mem::MaybeUninit, ptr::NonNull};
+
+/// An intrusive circular doubly-linked list.
+///
+/// Membership of elements of the list must be tracked by the owner of the list.
+///
+/// While elements of the list must remain pinned while in the list, the list itself does not
+/// require pinning. In other words, users are allowed to move instances of [`List`].
+///
+/// # Invariants
+///
+/// The links of an entry are wrapped in [`UnsafeCell`] and they are acessible when the list itself
+/// is. For example, when a thread has a mutable reference to a list, it may also safely get
+/// mutable references to the links of the elements in the list.
+///
+/// The links of an entry are also wrapped in [`MaybeUninit`] and they are initialised when they
+/// are present in a list. Otherwise they are uninitialised.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::unsafe_list::{Adapter, Links, List};
+///
+/// struct Example {
+///     v: usize,
+///     links: Links<Example>,
+/// }
+///
+/// // SAFETY: This adapter is the only one that uses `Example::links`.
+/// unsafe impl Adapter for Example {
+///     type EntryType = Self;
+///     fn to_links(obj: &Self) -> &Links<Self> {
+///         &obj.links
+///     }
+/// }
+///
+/// let a = Example {
+///     v: 0,
+///     links: Links::new(),
+/// };
+/// let b = Example {
+///     v: 1,
+///     links: Links::new(),
+/// };
+///
+/// let mut list = List::<Example>::new();
+/// assert!(list.is_empty());
+///
+/// // SAFETY: `a` was declared above, it's not in any lists yet, is never moved, and outlives the
+/// // list.
+/// unsafe { list.push_back(&a) };
+///
+/// // SAFETY: `b` was declared above, it's not in any lists yet, is never moved, and outlives the
+/// // list.
+/// unsafe { list.push_back(&b) };
+///
+/// assert!(core::ptr::eq(&a, list.front().unwrap().as_ptr()));
+/// assert!(core::ptr::eq(&b, list.back().unwrap().as_ptr()));
+///
+/// for (i, e) in list.iter().enumerate() {
+///     assert_eq!(i, e.v);
+/// }
+///
+/// for e in &list {
+///     pr_info!("{}", e.v);
+/// }
+///
+/// // SAFETY: `b` was added to the list above and wasn't removed yet.
+/// unsafe { list.remove(&b) };
+///
+/// assert!(core::ptr::eq(&a, list.front().unwrap().as_ptr()));
+/// assert!(core::ptr::eq(&a, list.back().unwrap().as_ptr()));
+/// ```
+pub struct List<A: Adapter + ?Sized> {
+    first: Option<NonNull<A::EntryType>>,
+}
+
+// SAFETY: The list is itself can be safely sent to other threads but we restrict it to being `Send`
+// only when its entries are also `Send`.
+unsafe impl<A: Adapter + ?Sized> Send for List<A> where A::EntryType: Send {}
+
+// SAFETY: The list is itself usable from other threads via references but we restrict it to being
+// `Sync` only when its entries are also `Sync`.
+unsafe impl<A: Adapter + ?Sized> Sync for List<A> where A::EntryType: Sync {}
+
+impl<A: Adapter + ?Sized> List<A> {
+    /// Constructs a new empty list.
+    pub const fn new() -> Self {
+        Self { first: None }
+    }
+
+    /// Determines if the list is empty.
+    pub fn is_empty(&self) -> bool {
+        self.first.is_none()
+    }
+
+    /// Inserts the only entry to a list.
+    ///
+    /// This must only be called when the list is empty.
+    pub fn insert_only_entry(&mut self, obj: &A::EntryType) {
+        let obj_ptr = NonNull::from(obj);
+
+        // SAFETY: We have mutable access to the list, so we also have access to the entry
+        // we're about to insert (and it's not in any other lists per the function safety
+        // requirements).
+        let obj_inner = unsafe { &mut *A::to_links(obj).0.get() };
+
+        // INVARIANTS: All fields of the links of the newly-inserted object are initialised
+        // below.
+        obj_inner.write(LinksInner {
+            next: obj_ptr,
+            prev: obj_ptr,
+            _pin: PhantomPinned,
+        });
+        self.first = Some(obj_ptr);
+    }
+
+    /// Adds the given object to the end of the list.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that:
+    /// - The object is not currently in any lists.
+    /// - The object remains alive until it is removed from the list.
+    /// - The object is not moved until it is removed from the list.
+    pub unsafe fn push_back(&mut self, obj: &A::EntryType) {
+        if let Some(first) = self.first {
+            // SAFETY: The previous entry to the first one is necessarily present in the list (it
+            // may in fact be the first entry itself as this is a circular list). The safety
+            // requirements of this function regarding `obj` satisfy those of `insert_after`.
+            unsafe { self.insert_after(self.inner_ref(first).prev, obj) };
+        } else {
+            self.insert_only_entry(obj);
+        }
+    }
+
+    /// Adds the given object to the beginning of the list.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that:
+    /// - The object is not currently in any lists.
+    /// - The object remains alive until it is removed from the list.
+    /// - The object is not moved until it is removed from the list.
+    pub unsafe fn push_front(&mut self, obj: &A::EntryType) {
+        if let Some(first) = self.first {
+            // SAFETY: The safety requirements of this function regarding `obj` satisfy those of
+            // `insert_before`. Additionally, `first` is in the list.
+            unsafe { self.insert_before(first, obj) };
+        } else {
+            self.insert_only_entry(obj);
+        }
+    }
+
+    /// Removes the given object from the list.
+    ///
+    /// # Safety
+    ///
+    /// The object must be in the list. In other words, the object must have previously been
+    /// inserted into this list and not removed yet.
+    pub unsafe fn remove(&mut self, entry: &A::EntryType) {
+        // SAFETY: Per the function safety requirements, `entry` is in the list.
+        let inner = unsafe { self.inner_ref(NonNull::from(entry)) };
+        let next = inner.next;
+        let prev = inner.prev;
+
+        // SAFETY: We have mutable access to the list, so we also have access to the entry we're
+        // about to remove (which we know is in the list per the function safety requirements).
+        let inner = unsafe { &mut *A::to_links(entry).0.get() };
+
+        // SAFETY: Since the entry was in the list, it was initialised.
+        unsafe { inner.assume_init_drop() };
+
+        if core::ptr::eq(next.as_ptr(), entry) {
+            // Removing the only element.
+            self.first = None;
+        } else {
+            // SAFETY: `prev` is in the list because it is pointed at by the entry being removed.
+            unsafe { self.inner(prev).next = next };
+            // SAFETY: `next` is in the list because it is pointed at by the entry being removed.
+            unsafe { self.inner(next).prev = prev };
+
+            if core::ptr::eq(self.first.unwrap().as_ptr(), entry) {
+                // Update the pointer to the first element as we're removing it.
+                self.first = Some(next);
+            }
+        }
+    }
+
+    /// Adds the given object after another object already in the list.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that:
+    /// - The existing object is currently in the list.
+    /// - The new object is not currently in any lists.
+    /// - The new object remains alive until it is removed from the list.
+    /// - The new object is not moved until it is removed from the list.
+    pub unsafe fn insert_after(&mut self, existing: NonNull<A::EntryType>, new: &A::EntryType) {
+        // SAFETY: We have mutable access to the list, so we also have access to the entry we're
+        // about to insert (and it's not in any other lists per the function safety requirements).
+        let new_inner = unsafe { &mut *A::to_links(new).0.get() };
+
+        // SAFETY: Per the function safety requirements, `existing` is in the list.
+        let existing_inner = unsafe { self.inner(existing) };
+        let next = existing_inner.next;
+
+        // INVARIANTS: All fields of the links of the newly-inserted object are initialised below.
+        new_inner.write(LinksInner {
+            next,
+            prev: existing,
+            _pin: PhantomPinned,
+        });
+
+        existing_inner.next = NonNull::from(new);
+
+        // SAFETY: `next` is in the list because it's pointed at by the existing entry.
+        unsafe { self.inner(next).prev = NonNull::from(new) };
+    }
+
+    /// Adds the given object before another object already in the list.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that:
+    /// - The existing object is currently in the list.
+    /// - The new object is not currently in any lists.
+    /// - The new object remains alive until it is removed from the list.
+    /// - The new object is not moved until it is removed from the list.
+    pub unsafe fn insert_before(&mut self, existing: NonNull<A::EntryType>, new: &A::EntryType) {
+        // SAFETY: The safety requirements of this function satisfy those of `insert_after`.
+        unsafe { self.insert_after(self.inner_ref(existing).prev, new) };
+
+        if self.first.unwrap() == existing {
+            // Update the pointer to the first element as we're inserting before it.
+            self.first = Some(NonNull::from(new));
+        }
+    }
+
+    /// Returns the first element of the list, if one exists.
+    pub fn front(&self) -> Option<NonNull<A::EntryType>> {
+        self.first
+    }
+
+    /// Returns the last element of the list, if one exists.
+    pub fn back(&self) -> Option<NonNull<A::EntryType>> {
+        // SAFETY: Having a pointer to it guarantees that the object is in the list.
+        self.first.map(|f| unsafe { self.inner_ref(f).prev })
+    }
+
+    /// Returns an iterator for the list starting at the first entry.
+    pub fn iter(&self) -> Iterator<'_, A> {
+        Iterator::new(self.cursor_front())
+    }
+
+    /// Returns an iterator for the list starting at the last entry.
+    pub fn iter_back(&self) -> impl iter::DoubleEndedIterator<Item = &'_ A::EntryType> {
+        Iterator::new(self.cursor_back())
+    }
+
+    /// Returns a cursor starting on the first (front) element of the list.
+    pub fn cursor_front(&self) -> Cursor<'_, A> {
+        // SAFETY: `front` is in the list (or is `None`) because we've read it from the list head
+        // and the list cannot have changed because we hold a shared reference to it.
+        unsafe { Cursor::new(self, self.front()) }
+    }
+
+    /// Returns a cursor starting on the last (back) element of the list.
+    pub fn cursor_back(&self) -> Cursor<'_, A> {
+        // SAFETY: `back` is in the list (or is `None`) because we've read it from the list head
+        // and the list cannot have changed because we hold a shared reference to it.
+        unsafe { Cursor::new(self, self.back()) }
+    }
+
+    /// Returns a mutable reference to the links of a given object.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that the element is in the list.
+    unsafe fn inner(&mut self, ptr: NonNull<A::EntryType>) -> &mut LinksInner<A::EntryType> {
+        // SAFETY: The safety requirements guarantee that we the links are initialised because
+        // that's part of the type invariants. Additionally, the type invariants also guarantee
+        // that having a mutable reference to the list guarantees that the links are mutably
+        // accessible as well.
+        unsafe { (*A::to_links(ptr.as_ref()).0.get()).assume_init_mut() }
+    }
+
+    /// Returns a shared reference to the links of a given object.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that the element is in the list.
+    unsafe fn inner_ref(&self, ptr: NonNull<A::EntryType>) -> &LinksInner<A::EntryType> {
+        // SAFETY: The safety requirements guarantee that we the links are initialised because
+        // that's part of the type invariants. Additionally, the type invariants also guarantee
+        // that having a shared reference to the list guarantees that the links are accessible in
+        // shared mode as well.
+        unsafe { (*A::to_links(ptr.as_ref()).0.get()).assume_init_ref() }
+    }
+}
+
+impl<'a, A: Adapter + ?Sized> iter::IntoIterator for &'a List<A> {
+    type Item = &'a A::EntryType;
+    type IntoIter = Iterator<'a, A>;
+    fn into_iter(self) -> Self::IntoIter {
+        self.iter()
+    }
+}
+
+/// An iterator for the linked list.
+pub struct Iterator<'a, A: Adapter + ?Sized> {
+    cursor: Cursor<'a, A>,
+}
+
+impl<'a, A: Adapter + ?Sized> Iterator<'a, A> {
+    fn new(cursor: Cursor<'a, A>) -> Self {
+        Self { cursor }
+    }
+}
+
+impl<'a, A: Adapter + ?Sized> iter::Iterator for Iterator<'a, A> {
+    type Item = &'a A::EntryType;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let ret = self.cursor.current()?;
+        self.cursor.move_next();
+        Some(ret)
+    }
+}
+
+impl<A: Adapter + ?Sized> iter::DoubleEndedIterator for Iterator<'_, A> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let ret = self.cursor.current()?;
+        self.cursor.move_prev();
+        Some(ret)
+    }
+}
+
+/// A linked-list adapter.
+///
+/// It is a separate type (as opposed to implemented by the type of the elements of the list)
+/// so that a given type can be inserted into multiple lists at the same time; in such cases, each
+/// list needs its own adapter that returns a different pointer to links.
+///
+/// It may, however, be implemented by the type itself to be inserted into lists, which makes it
+/// more readable.
+///
+/// # Safety
+///
+/// Implementers must ensure that the links returned by [`Adapter::to_links`] are unique to the
+/// adapter. That is, different adapters must return different links for a given object.
+///
+/// The reason for this requirement is to avoid confusion that may lead to UB. In particular, if
+/// two adapters were to use the same links, a user may have two lists (one for each adapter) and
+/// try to insert the same object into both at the same time; although this clearly violates the
+/// list safety requirements (e.g., those in [`List::push_back`]), for users to notice it, they'd
+/// have to dig into the details of the two adapters.
+///
+/// By imposing the requirement on the adapter, we make it easier for users to check compliance
+/// with the requirements when using the list.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::unsafe_list::{Adapter, Links, List};
+///
+/// struct Example {
+///     a: u32,
+///     b: u32,
+///     links1: Links<Example>,
+///     links2: Links<Example>,
+/// }
+///
+/// // SAFETY: This adapter is the only one that uses `Example::links1`.
+/// unsafe impl Adapter for Example {
+///     type EntryType = Self;
+///     fn to_links(obj: &Self) -> &Links<Self> {
+///         &obj.links1
+///     }
+/// }
+///
+/// struct ExampleAdapter;
+///
+/// // SAFETY: This adapter is the only one that uses `Example::links2`.
+/// unsafe impl Adapter for ExampleAdapter {
+///     type EntryType = Example;
+///     fn to_links(obj: &Example) -> &Links<Example> {
+///         &obj.links2
+///     }
+/// }
+///
+/// static LIST1: List<Example> = List::new();
+/// static LIST2: List<ExampleAdapter> = List::new();
+/// ```
+pub unsafe trait Adapter {
+    /// The type of the enties in the list.
+    type EntryType: ?Sized;
+
+    /// Retrieves the linked list links for the given object.
+    fn to_links(obj: &Self::EntryType) -> &Links<Self::EntryType>;
+}
+
+struct LinksInner<T: ?Sized> {
+    next: NonNull<T>,
+    prev: NonNull<T>,
+    _pin: PhantomPinned,
+}
+
+/// Links of a linked list.
+///
+/// List entries need one of these per concurrent list.
+pub struct Links<T: ?Sized>(UnsafeCell<MaybeUninit<LinksInner<T>>>);
+
+// SAFETY: `Links` can be safely sent to other threads but we restrict it to being `Send` only when
+// the list entries it points to are also `Send`.
+unsafe impl<T: ?Sized> Send for Links<T> {}
+
+// SAFETY: `Links` is usable from other threads via references but we restrict it to being `Sync`
+// only when the list entries it points to are also `Sync`.
+unsafe impl<T: ?Sized> Sync for Links<T> {}
+
+impl<T: ?Sized> Links<T> {
+    /// Constructs a new instance of the linked-list links.
+    pub const fn new() -> Self {
+        Self(UnsafeCell::new(MaybeUninit::uninit()))
+    }
+}
+
+pub(crate) struct CommonCursor<A: Adapter + ?Sized> {
+    pub(crate) cur: Option<NonNull<A::EntryType>>,
+}
+
+impl<A: Adapter + ?Sized> CommonCursor<A> {
+    pub(crate) fn new(cur: Option<NonNull<A::EntryType>>) -> Self {
+        Self { cur }
+    }
+
+    /// Moves the cursor to the next entry of the list.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that the cursor is either [`None`] or points to an entry that is in
+    /// `list`.
+    pub(crate) unsafe fn move_next(&mut self, list: &List<A>) {
+        match self.cur.take() {
+            None => self.cur = list.first,
+            Some(cur) => {
+                if let Some(head) = list.first {
+                    // SAFETY: Per the function safety requirements, `cur` is in the list.
+                    let links = unsafe { list.inner_ref(cur) };
+                    if links.next != head {
+                        self.cur = Some(links.next);
+                    }
+                }
+            }
+        }
+    }
+
+    /// Moves the cursor to the previous entry of the list.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that the cursor is either [`None`] or points to an entry that is in
+    /// `list`.
+    pub(crate) unsafe fn move_prev(&mut self, list: &List<A>) {
+        match list.first {
+            None => self.cur = None,
+            Some(head) => {
+                let next = match self.cur.take() {
+                    None => head,
+                    Some(cur) => {
+                        if cur == head {
+                            return;
+                        }
+                        cur
+                    }
+                };
+                // SAFETY: `next` is either `head` or `cur`. The former is in the list because it's
+                // its head; the latter is in the list per the function safety requirements.
+                self.cur = Some(unsafe { list.inner_ref(next) }.prev);
+            }
+        }
+    }
+}
+
+/// A list cursor that allows traversing a linked list and inspecting elements.
+pub struct Cursor<'a, A: Adapter + ?Sized> {
+    cursor: CommonCursor<A>,
+    list: &'a List<A>,
+}
+
+impl<'a, A: Adapter + ?Sized> Cursor<'a, A> {
+    /// Creates a new cursor.
+    ///
+    /// # Safety
+    ///
+    /// Callers must ensure that `cur` is either [`None`] or points to an entry in `list`.
+    pub(crate) unsafe fn new(list: &'a List<A>, cur: Option<NonNull<A::EntryType>>) -> Self {
+        Self {
+            list,
+            cursor: CommonCursor::new(cur),
+        }
+    }
+
+    /// Returns the element the cursor is currently positioned on.
+    pub fn current(&self) -> Option<&'a A::EntryType> {
+        let cur = self.cursor.cur?;
+        // SAFETY: `cursor` starts off in the list and only changes within the list. Additionally,
+        // the list cannot change because we hold a shared reference to it, so the cursor is always
+        // within the list.
+        Some(unsafe { cur.as_ref() })
+    }
+
+    /// Moves the cursor to the next element.
+    pub fn move_next(&mut self) {
+        // SAFETY: `cursor` starts off in the list and only changes within the list. Additionally,
+        // the list cannot change because we hold a shared reference to it, so the cursor is always
+        // within the list.
+        unsafe { self.cursor.move_next(self.list) };
+    }
+
+    /// Moves the cursor to the previous element.
+    pub fn move_prev(&mut self) {
+        // SAFETY: `cursor` starts off in the list and only changes within the list. Additionally,
+        // the list cannot change because we hold a shared reference to it, so the cursor is always
+        // within the list.
+        unsafe { self.cursor.move_prev(self.list) };
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use alloc::{boxed::Box, vec::Vec};
+    use core::ptr::NonNull;
+
+    struct Example {
+        links: super::Links<Self>,
+    }
+
+    // SAFETY: This is the only adapter that uses `Example::links`.
+    unsafe impl super::Adapter for Example {
+        type EntryType = Self;
+        fn to_links(obj: &Self) -> &super::Links<Self> {
+            &obj.links
+        }
+    }
+
+    fn build_vector(size: usize) -> Vec<Box<Example>> {
+        let mut v = Vec::new();
+        v.reserve(size);
+        for _ in 0..size {
+            v.push(Box::new(Example {
+                links: super::Links::new(),
+            }));
+        }
+        v
+    }
+
+    #[track_caller]
+    fn assert_list_contents(v: &[Box<Example>], list: &super::List<Example>) {
+        let n = v.len();
+
+        // Assert that the list is ok going forward.
+        let mut count = 0;
+        for (i, e) in list.iter().enumerate() {
+            assert!(core::ptr::eq(e, &*v[i]));
+            count += 1;
+        }
+        assert_eq!(count, n);
+
+        // Assert that the list is ok going backwards.
+        let mut count = 0;
+        for (i, e) in list.iter_back().rev().enumerate() {
+            assert!(core::ptr::eq(e, &*v[n - 1 - i]));
+            count += 1;
+        }
+        assert_eq!(count, n);
+    }
+
+    #[track_caller]
+    fn test_each_element(
+        min_len: usize,
+        max_len: usize,
+        test: impl Fn(&mut Vec<Box<Example>>, &mut super::List<Example>, usize, Box<Example>),
+    ) {
+        for n in min_len..=max_len {
+            for i in 0..n {
+                let extra = Box::new(Example {
+                    links: super::Links::new(),
+                });
+                let mut v = build_vector(n);
+                let mut list = super::List::<Example>::new();
+
+                // Build list.
+                for j in 0..n {
+                    // SAFETY: The entry was allocated above, it's not in any lists yet, is never
+                    // moved, and outlives the list.
+                    unsafe { list.push_back(&v[j]) };
+                }
+
+                // Call the test case.
+                test(&mut v, &mut list, i, extra);
+
+                // Check that the list is ok.
+                assert_list_contents(&v, &list);
+            }
+        }
+    }
+
+    #[test]
+    fn test_push_back() {
+        const MAX: usize = 10;
+        let v = build_vector(MAX);
+        let mut list = super::List::<Example>::new();
+
+        for n in 1..=MAX {
+            // SAFETY: The entry was allocated above, it's not in any lists yet, is never moved,
+            // and outlives the list.
+            unsafe { list.push_back(&v[n - 1]) };
+            assert_list_contents(&v[..n], &list);
+        }
+    }
+
+    #[test]
+    fn test_push_front() {
+        const MAX: usize = 10;
+        let v = build_vector(MAX);
+        let mut list = super::List::<Example>::new();
+
+        for n in 1..=MAX {
+            // SAFETY: The entry was allocated above, it's not in any lists yet, is never moved,
+            // and outlives the list.
+            unsafe { list.push_front(&v[MAX - n]) };
+            assert_list_contents(&v[MAX - n..], &list);
+        }
+    }
+
+    #[test]
+    fn test_one_removal() {
+        test_each_element(1, 10, |v, list, i, _| {
+            // Remove the i-th element.
+            // SAFETY: The i-th element was added to the list above, and wasn't removed yet.
+            unsafe { list.remove(&v[i]) };
+            v.remove(i);
+        });
+    }
+
+    #[test]
+    fn test_one_insert_after() {
+        test_each_element(1, 10, |v, list, i, extra| {
+            // Insert after the i-th element.
+            // SAFETY: The i-th element was added to the list above, and wasn't removed yet.
+            // Additionally, the new element isn't in any list yet, isn't moved, and outlives
+            // the list.
+            unsafe { list.insert_after(NonNull::from(&*v[i]), &*extra) };
+            v.insert(i + 1, extra);
+        });
+    }
+
+    #[test]
+    fn test_one_insert_before() {
+        test_each_element(1, 10, |v, list, i, extra| {
+            // Insert before the i-th element.
+            // SAFETY: The i-th element was added to the list above, and wasn't removed yet.
+            // Additionally, the new element isn't in any list yet, isn't moved, and outlives
+            // the list.
+            unsafe { list.insert_before(NonNull::from(&*v[i]), &*extra) };
+            v.insert(i, extra);
+        });
+    }
+}
diff --git a/rust/kernel/user_ptr.rs b/rust/kernel/user_ptr.rs
new file mode 100644
index 000000000000..0bc2c7f1331e
--- /dev/null
+++ b/rust/kernel/user_ptr.rs
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! User pointers.
+//!
+//! C header: [`include/linux/uaccess.h`](../../../../include/linux/uaccess.h)
+
+use crate::{
+    bindings,
+    error::code::*,
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    Result,
+};
+use alloc::vec::Vec;
+
+/// A reference to an area in userspace memory, which can be either
+/// read-only or read-write.
+///
+/// All methods on this struct are safe: invalid pointers return
+/// `EFAULT`. Concurrent access, *including data races to/from userspace
+/// memory*, is permitted, because fundamentally another userspace
+/// thread/process could always be modifying memory at the same time
+/// (in the same way that userspace Rust's [`std::io`] permits data races
+/// with the contents of files on disk). In the presence of a race, the
+/// exact byte values read/written are unspecified but the operation is
+/// well-defined. Kernelspace code should validate its copy of data
+/// after completing a read, and not expect that multiple reads of the
+/// same address will return the same value.
+///
+/// All APIs enforce the invariant that a given byte of memory from userspace
+/// may only be read once. By preventing double-fetches we avoid TOCTOU
+/// vulnerabilities. This is accomplished by taking `self` by value to prevent
+/// obtaining multiple readers on a given [`UserSlicePtr`], and the readers
+/// only permitting forward reads.
+///
+/// Constructing a [`UserSlicePtr`] performs no checks on the provided
+/// address and length, it can safely be constructed inside a kernel thread
+/// with no current userspace process. Reads and writes wrap the kernel APIs
+/// `copy_from_user` and `copy_to_user`, which check the memory map of the
+/// current process and enforce that the address range is within the user
+/// range (no additional calls to `access_ok` are needed).
+///
+/// [`std::io`]: https://doc.rust-lang.org/std/io/index.html
+pub struct UserSlicePtr(*mut core::ffi::c_void, usize);
+
+impl UserSlicePtr {
+    /// Constructs a user slice from a raw pointer and a length in bytes.
+    ///
+    /// # Safety
+    ///
+    /// Callers must be careful to avoid time-of-check-time-of-use
+    /// (TOCTOU) issues. The simplest way is to create a single instance of
+    /// [`UserSlicePtr`] per user memory block as it reads each byte at
+    /// most once.
+    pub unsafe fn new(ptr: *mut core::ffi::c_void, length: usize) -> Self {
+        UserSlicePtr(ptr, length)
+    }
+
+    /// Reads the entirety of the user slice.
+    ///
+    /// Returns `EFAULT` if the address does not currently point to
+    /// mapped, readable memory.
+    pub fn read_all(self) -> Result<Vec<u8>> {
+        self.reader().read_all()
+    }
+
+    /// Constructs a [`UserSlicePtrReader`].
+    pub fn reader(self) -> UserSlicePtrReader {
+        UserSlicePtrReader(self.0, self.1)
+    }
+
+    /// Writes the provided slice into the user slice.
+    ///
+    /// Returns `EFAULT` if the address does not currently point to
+    /// mapped, writable memory (in which case some data from before the
+    /// fault may be written), or `data` is larger than the user slice
+    /// (in which case no data is written).
+    pub fn write_all(self, data: &[u8]) -> Result {
+        self.writer().write_slice(data)
+    }
+
+    /// Constructs a [`UserSlicePtrWriter`].
+    pub fn writer(self) -> UserSlicePtrWriter {
+        UserSlicePtrWriter(self.0, self.1)
+    }
+
+    /// Constructs both a [`UserSlicePtrReader`] and a [`UserSlicePtrWriter`].
+    pub fn reader_writer(self) -> (UserSlicePtrReader, UserSlicePtrWriter) {
+        (
+            UserSlicePtrReader(self.0, self.1),
+            UserSlicePtrWriter(self.0, self.1),
+        )
+    }
+}
+
+/// A reader for [`UserSlicePtr`].
+///
+/// Used to incrementally read from the user slice.
+pub struct UserSlicePtrReader(*mut core::ffi::c_void, usize);
+
+impl IoBufferReader for UserSlicePtrReader {
+    /// Returns the number of bytes left to be read from this.
+    ///
+    /// Note that even reading less than this number of bytes may fail.
+    fn len(&self) -> usize {
+        self.1
+    }
+
+    /// Reads raw data from the user slice into a raw kernel buffer.
+    ///
+    /// # Safety
+    ///
+    /// The output buffer must be valid.
+    unsafe fn read_raw(&mut self, out: *mut u8, len: usize) -> Result {
+        if len > self.1 || len > u32::MAX as usize {
+            return Err(EFAULT);
+        }
+        let res = unsafe { bindings::copy_from_user(out as _, self.0, len as _) };
+        if res != 0 {
+            return Err(EFAULT);
+        }
+        // Since this is not a pointer to a valid object in our program,
+        // we cannot use `add`, which has C-style rules for defined
+        // behavior.
+        self.0 = self.0.wrapping_add(len);
+        self.1 -= len;
+        Ok(())
+    }
+}
+
+/// A writer for [`UserSlicePtr`].
+///
+/// Used to incrementally write into the user slice.
+pub struct UserSlicePtrWriter(*mut core::ffi::c_void, usize);
+
+impl IoBufferWriter for UserSlicePtrWriter {
+    fn len(&self) -> usize {
+        self.1
+    }
+
+    fn clear(&mut self, mut len: usize) -> Result {
+        let mut ret = Ok(());
+        if len > self.1 {
+            ret = Err(EFAULT);
+            len = self.1;
+        }
+
+        // SAFETY: The buffer will be validated by `clear_user`. We ensure that `len` is within
+        // bounds in the check above.
+        let left = unsafe { bindings::clear_user(self.0, len as _) } as usize;
+        if left != 0 {
+            ret = Err(EFAULT);
+            len -= left;
+        }
+
+        self.0 = self.0.wrapping_add(len);
+        self.1 -= len;
+        ret
+    }
+
+    unsafe fn write_raw(&mut self, data: *const u8, len: usize) -> Result {
+        if len > self.1 || len > u32::MAX as usize {
+            return Err(EFAULT);
+        }
+        let res = unsafe { bindings::copy_to_user(self.0, data as _, len as _) };
+        if res != 0 {
+            return Err(EFAULT);
+        }
+        // Since this is not a pointer to a valid object in our program,
+        // we cannot use `add`, which has C-style rules for defined
+        // behavior.
+        self.0 = self.0.wrapping_add(len);
+        self.1 -= len;
+        Ok(())
+    }
+}
diff --git a/rust/kernel/workqueue.rs b/rust/kernel/workqueue.rs
new file mode 100644
index 000000000000..c6b89f137469
--- /dev/null
+++ b/rust/kernel/workqueue.rs
@@ -0,0 +1,512 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Work queues.
+//!
+//! C header: [`include/linux/workqueue.h`](../../../../include/linux/workqueue.h)
+
+use crate::{
+    bindings, c_str,
+    error::code::*,
+    sync::{LockClassKey, Ref, UniqueRef},
+    Opaque, Result,
+};
+use core::{fmt, ops::Deref, ptr::NonNull};
+
+/// Spawns a new work item to run in the work queue.
+///
+/// It also automatically defines a new lockdep lock class for the work item.
+#[macro_export]
+macro_rules! spawn_work_item {
+    ($queue:expr, $func:expr) => {{
+        static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        $crate::workqueue::Queue::try_spawn($queue, &CLASS, $func)
+    }};
+}
+
+/// Implements the [`WorkAdapter`] trait for a type where its [`Work`] instance is a field.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::workqueue::Work;
+///
+/// struct Example {
+///     work: Work,
+/// }
+///
+/// kernel::impl_self_work_adapter!(Example, work, |_| {});
+/// ```
+#[macro_export]
+macro_rules! impl_self_work_adapter {
+    ($work_type:ty, $field:ident, $closure:expr) => {
+        $crate::impl_work_adapter!($work_type, $work_type, $field, $closure);
+    };
+}
+
+/// Implements the [`WorkAdapter`] trait for an adapter type.
+///
+/// # Examples
+///
+/// ```
+/// # use kernel::workqueue::Work;
+///
+/// struct Example {
+///     work: Work,
+/// }
+///
+/// struct Adapter;
+///
+/// kernel::impl_work_adapter!(Adapter, Example, work, |_| {});
+/// ```
+#[macro_export]
+macro_rules! impl_work_adapter {
+    ($adapter:ty, $work_type:ty, $field:ident, $closure:expr) => {
+        // SAFETY: We use `offset_of` to ensure that the field is within the given type, and we
+        // also check its type is `Work`.
+        unsafe impl $crate::workqueue::WorkAdapter for $adapter {
+            type Target = $work_type;
+            const FIELD_OFFSET: isize = $crate::offset_of!(Self::Target, $field);
+            fn run(w: $crate::sync::Ref<Self::Target>) {
+                let closure: fn($crate::sync::Ref<Self::Target>) = $closure;
+                closure(w);
+                return;
+
+                // Checks that the type of the field is actually `Work`.
+                let tmp = core::mem::MaybeUninit::<$work_type>::uninit();
+                // SAFETY: The pointer is valid and aligned, just not initialised; `addr_of`
+                // ensures that we don't actually read from it (which would be UB) nor create an
+                // intermediate reference.
+                let _x: *const $crate::workqueue::Work =
+                    unsafe { core::ptr::addr_of!((*tmp.as_ptr()).$field) };
+            }
+        }
+    };
+}
+
+/// Initialises a work item.
+///
+/// It automatically defines a new lockdep lock class for the work item.
+#[macro_export]
+macro_rules! init_work_item {
+    ($work_container:expr) => {{
+        static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        $crate::workqueue::Work::init($work_container, &CLASS)
+    }};
+}
+
+/// Initialises a work item with the given adapter.
+///
+/// It automatically defines a new lockdep lock class for the work item.
+#[macro_export]
+macro_rules! init_work_item_adapter {
+    ($adapter:ty, $work_container:expr) => {{
+        static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+        $crate::workqueue::Work::init_with_adapter::<$adapter>($work_container, &CLASS)
+    }};
+}
+
+/// A kernel work queue.
+///
+/// Wraps the kernel's C `struct workqueue_struct`.
+///
+/// It allows work items to be queued to run on thread pools managed by the kernel. Several are
+/// always available, for example, the ones returned by [`system`], [`system_highpri`],
+/// [`system_long`], etc.
+///
+/// # Examples
+///
+/// The following example is the simplest way to launch a work item:
+///
+/// ```
+/// # use kernel::{spawn_work_item, workqueue};
+///
+/// # fn example() -> Result {
+/// spawn_work_item!(workqueue::system(), || pr_info!("Hello from a work item\n"))?;
+/// #     Ok(())
+/// # }
+///
+/// # example().unwrap()
+/// ```
+///
+/// The following example is used to create a work item and enqueue it several times. We note that
+/// enqueuing while the work item is already queued is a no-op, so we enqueue it when it is not
+/// enqueued yet.
+///
+/// ```
+/// # use kernel::workqueue::{self, Work};
+/// use core::sync::atomic::{AtomicU32, Ordering};
+/// use kernel::sync::UniqueRef;
+///
+/// struct Example {
+///     count: AtomicU32,
+///     work: Work,
+/// }
+///
+/// kernel::impl_self_work_adapter!(Example, work, |w| {
+///     let count = w.count.fetch_add(1, Ordering::Relaxed);
+///     pr_info!("Called with count={}\n", count);
+///
+///     // Queue again if the count is less than 10.
+///     if count < 10 {
+///         workqueue::system().enqueue(w);
+///     }
+/// });
+///
+/// # fn example() -> Result {
+/// let e = UniqueRef::try_new(Example {
+///     count: AtomicU32::new(0),
+///     // SAFETY: `work` is initialised below.
+///     work: unsafe { Work::new() },
+/// })?;
+///
+/// kernel::init_work_item!(&e);
+///
+/// // Queue the first time.
+/// workqueue::system().enqueue(e.into());
+/// #     Ok(())
+/// # }
+///
+/// # example().unwrap()
+/// ```
+///
+/// The following example has two different work items in the same struct, which allows it to be
+/// queued twice.
+///
+/// ```
+/// # use kernel::workqueue::{self, Work, WorkAdapter};
+/// use core::sync::atomic::{AtomicU32, Ordering};
+/// use kernel::sync::{Ref, UniqueRef};
+///
+/// struct Example {
+///     work1: Work,
+///     work2: Work,
+/// }
+///
+/// kernel::impl_self_work_adapter!(Example, work1, |_| pr_info!("First work\n"));
+///
+/// struct SecondAdapter;
+/// kernel::impl_work_adapter!(SecondAdapter, Example, work2, |_| pr_info!("Second work\n"));
+///
+/// # fn example() -> Result {
+/// let e = UniqueRef::try_new(Example {
+///     // SAFETY: `work1` is initialised below.
+///     work1: unsafe { Work::new() },
+///     // SAFETY: `work2` is initialised below.
+///     work2: unsafe { Work::new() },
+/// })?;
+///
+/// kernel::init_work_item!(&e);
+/// kernel::init_work_item_adapter!(SecondAdapter, &e);
+///
+/// let e = Ref::from(e);
+///
+/// // Enqueue the two different work items.
+/// workqueue::system().enqueue(e.clone());
+/// workqueue::system().enqueue_adapter::<SecondAdapter>(e);
+/// #     Ok(())
+/// # }
+///
+/// # example().unwrap()
+/// ```
+#[repr(transparent)]
+pub struct Queue(Opaque<bindings::workqueue_struct>);
+
+// SAFETY: Kernel workqueues are usable from any thread.
+unsafe impl Sync for Queue {}
+
+impl Queue {
+    /// Tries to allocate a new work queue.
+    ///
+    /// Callers should first consider using one of the existing ones (e.g. [`system`]) before
+    /// deciding to create a new one.
+    pub fn try_new(name: fmt::Arguments<'_>) -> Result<BoxedQueue> {
+        // SAFETY: We use a format string that requires an `fmt::Arguments` pointer as the first
+        // and only argument.
+        let ptr = unsafe {
+            bindings::alloc_workqueue(
+                c_str!("%pA").as_char_ptr(),
+                0,
+                0,
+                &name as *const _ as *const core::ffi::c_void,
+            )
+        };
+        if ptr.is_null() {
+            return Err(ENOMEM);
+        }
+
+        // SAFETY: `ptr` was just allocated and checked above, so it non-null and valid. Plus, it
+        // isn't touched after the call below, so ownership is transferred.
+        Ok(unsafe { BoxedQueue::new(ptr) })
+    }
+
+    /// Enqueues a work item.
+    ///
+    /// Returns `true` if the work item was successfully enqueue; returns `false` if it had already
+    /// been (and continued to be) enqueued.
+    pub fn enqueue<T: WorkAdapter<Target = T>>(&self, w: Ref<T>) -> bool {
+        self.enqueue_adapter::<T>(w)
+    }
+
+    /// Enqueues a work item with an explicit adapter.
+    ///
+    /// Returns `true` if the work item was successfully enqueue; returns `false` if it had already
+    /// been (and continued to be) enqueued.
+    pub fn enqueue_adapter<A: WorkAdapter + ?Sized>(&self, w: Ref<A::Target>) -> bool {
+        let ptr = Ref::into_raw(w);
+        let field_ptr =
+            (ptr as *const u8).wrapping_offset(A::FIELD_OFFSET) as *mut bindings::work_struct;
+
+        // SAFETY: Having a shared reference to work queue guarantees that it remains valid, while
+        // the work item remains valid because we called `into_raw` and only call `from_raw` again
+        // if the object was already queued (so a previous call already guarantees it remains
+        // alive), when the work item runs, or when the work item is canceled.
+        let ret = unsafe {
+            bindings::queue_work_on(bindings::WORK_CPU_UNBOUND as _, self.0.get(), field_ptr)
+        };
+
+        if !ret {
+            // SAFETY: `ptr` comes from a previous call to `into_raw`. Additionally, given that
+            // `queue_work_on` returned `false`, we know that no-one is going to use the result of
+            // `into_raw`, so we must drop it here to avoid a reference leak.
+            unsafe { Ref::from_raw(ptr) };
+        }
+
+        ret
+    }
+
+    /// Tries to spawn the given function or closure as a work item.
+    ///
+    /// Users are encouraged to use [`spawn_work_item`] as it automatically defines the lock class
+    /// key to be used.
+    pub fn try_spawn<T: 'static + Send + Fn()>(
+        &self,
+        key: &'static LockClassKey,
+        func: T,
+    ) -> Result {
+        let w = UniqueRef::<ClosureAdapter<T>>::try_new(ClosureAdapter {
+            // SAFETY: `work` is initialised below.
+            work: unsafe { Work::new() },
+            func,
+        })?;
+        Work::init(&w, key);
+        self.enqueue(w.into());
+        Ok(())
+    }
+}
+
+struct ClosureAdapter<T: Fn() + Send> {
+    work: Work,
+    func: T,
+}
+
+// SAFETY: `ClosureAdapter::work` is of type `Work`.
+unsafe impl<T: Fn() + Send> WorkAdapter for ClosureAdapter<T> {
+    type Target = Self;
+    const FIELD_OFFSET: isize = crate::offset_of!(Self, work);
+
+    fn run(w: Ref<Self::Target>) {
+        (w.func)();
+    }
+}
+
+/// An adapter for work items.
+///
+/// For the most usual case where a type has a [`Work`] in it and is itself the adapter, it is
+/// recommended that they use the [`impl_self_work_adapter`] or [`impl_work_adapter`] macros
+/// instead of implementing the [`WorkAdapter`] manually. The great advantage is that they don't
+/// require any unsafe blocks.
+///
+/// # Safety
+///
+/// Implementers must ensure that there is a [`Work`] instance `FIELD_OFFSET` bytes from the
+/// beginning of a valid `Target` type. It is normally safe to use the [`crate::offset_of`] macro
+/// for this.
+pub unsafe trait WorkAdapter {
+    /// The type that this work adapter is meant to use.
+    type Target;
+
+    /// The offset, in bytes, from the beginning of [`Self::Target`] to the instance of [`Work`].
+    const FIELD_OFFSET: isize;
+
+    /// Runs when the work item is picked up for execution after it has been enqueued to some work
+    /// queue.
+    fn run(w: Ref<Self::Target>);
+}
+
+/// A work item.
+///
+/// Wraps the kernel's C `struct work_struct`.
+///
+/// Users must add a field of this type to a structure, then implement [`WorkAdapter`] so that it
+/// can be queued for execution in a thread pool. Examples of it being used are available in the
+/// documentation for [`Queue`].
+#[repr(transparent)]
+pub struct Work(Opaque<bindings::work_struct>);
+
+impl Work {
+    /// Creates a new instance of [`Work`].
+    ///
+    /// # Safety
+    ///
+    /// Callers must call either [`Work::init`] or [`Work::init_with_adapter`] before the work item
+    /// can be used.
+    pub unsafe fn new() -> Self {
+        Self(Opaque::uninit())
+    }
+
+    /// Initialises the work item.
+    ///
+    /// Users should prefer the [`init_work_item`] macro because it automatically defines a new
+    /// lock class key.
+    pub fn init<T: WorkAdapter<Target = T>>(obj: &UniqueRef<T>, key: &'static LockClassKey) {
+        Self::init_with_adapter::<T>(obj, key)
+    }
+
+    /// Initialises the work item with the given adapter.
+    ///
+    /// Users should prefer the [`init_work_item_adapter`] macro because it automatically defines a
+    /// new lock class key.
+    pub fn init_with_adapter<A: WorkAdapter>(
+        obj: &UniqueRef<A::Target>,
+        key: &'static LockClassKey,
+    ) {
+        let ptr = &**obj as *const _ as *const u8;
+        let field_ptr = ptr.wrapping_offset(A::FIELD_OFFSET) as *mut bindings::work_struct;
+
+        // SAFETY: `work` is valid for writes -- the `UniqueRef` instance guarantees that it has
+        // been allocated and there is only one pointer to it. Additionally, `work_func` is a valid
+        // callback for the work item.
+        unsafe {
+            bindings::__INIT_WORK_WITH_KEY(field_ptr, Some(Self::work_func::<A>), false, key.get())
+        };
+    }
+
+    /// Cancels the work item.
+    ///
+    /// It is ok for this to be called when the work is not queued.
+    pub fn cancel(&self) {
+        // SAFETY: The work is valid (we have a reference to it), and the function can be called
+        // whether the work is queued or not.
+        if unsafe { bindings::cancel_work_sync(self.0.get()) } {
+            // SAFETY: When the work was queued, a call to `into_raw` was made. We just canceled
+            // the work without it having the chance to run, so we need to explicitly destroy this
+            // reference (which would have happened in `work_func` if it did run).
+            unsafe { Ref::from_raw(&*self) };
+        }
+    }
+
+    unsafe extern "C" fn work_func<A: WorkAdapter>(work: *mut bindings::work_struct) {
+        let field_ptr = work as *const _ as *const u8;
+        let ptr = field_ptr.wrapping_offset(-A::FIELD_OFFSET) as *const A::Target;
+
+        // SAFETY: This callback is only ever used by the `init_with_adapter` method, so it is
+        // always the case that the work item is embedded in a `Work` (Self) struct.
+        let w = unsafe { Ref::from_raw(ptr) };
+        A::run(w);
+    }
+}
+
+/// A boxed owned workqueue.
+///
+/// # Invariants
+///
+/// `ptr` is owned by this instance of [`BoxedQueue`], so it's always valid.
+pub struct BoxedQueue {
+    ptr: NonNull<Queue>,
+}
+
+impl BoxedQueue {
+    /// Creates a new instance of [`BoxedQueue`].
+    ///
+    /// # Safety
+    ///
+    /// `ptr` must be non-null and valid. Additionally, ownership must be handed over to new
+    /// instance of [`BoxedQueue`].
+    unsafe fn new(ptr: *mut bindings::workqueue_struct) -> Self {
+        Self {
+            // SAFETY: We checked above that `ptr` is non-null.
+            ptr: unsafe { NonNull::new_unchecked(ptr.cast()) },
+        }
+    }
+}
+
+impl Deref for BoxedQueue {
+    type Target = Queue;
+
+    fn deref(&self) -> &Queue {
+        // SAFETY: The type invariants guarantee that `ptr` is always valid.
+        unsafe { self.ptr.as_ref() }
+    }
+}
+
+impl Drop for BoxedQueue {
+    fn drop(&mut self) {
+        // SAFETY: The type invariants guarantee that `ptr` is always valid.
+        unsafe { bindings::destroy_workqueue(self.ptr.as_ref().0.get()) };
+    }
+}
+
+/// Returns the system work queue (`system_wq`).
+///
+/// It is the one used by schedule\[_delayed\]_work\[_on\](). Multi-CPU multi-threaded. There are
+/// users which expect relatively short queue flush time.
+///
+/// Callers shouldn't queue work items which can run for too long.
+pub fn system() -> &'static Queue {
+    // SAFETY: `system_wq` is a C global, always available.
+    unsafe { &*bindings::system_wq.cast() }
+}
+
+/// Returns the system high-priority work queue (`system_highpri_wq`).
+///
+/// It is similar to the one returned by [`system`] but for work items which require higher
+/// scheduling priority.
+pub fn system_highpri() -> &'static Queue {
+    // SAFETY: `system_highpri_wq` is a C global, always available.
+    unsafe { &*bindings::system_highpri_wq.cast() }
+}
+
+/// Returns the system work queue for potentially long-running work items (`system_long_wq`).
+///
+/// It is similar to the one returned by [`system`] but may host long running work items. Queue
+/// flushing might take relatively long.
+pub fn system_long() -> &'static Queue {
+    // SAFETY: `system_long_wq` is a C global, always available.
+    unsafe { &*bindings::system_long_wq.cast() }
+}
+
+/// Returns the system unbound work queue (`system_unbound_wq`).
+///
+/// Workers are not bound to any specific CPU, not concurrency managed, and all queued work items
+/// are executed immediately as long as `max_active` limit is not reached and resources are
+/// available.
+pub fn system_unbound() -> &'static Queue {
+    // SAFETY: `system_unbound_wq` is a C global, always available.
+    unsafe { &*bindings::system_unbound_wq.cast() }
+}
+
+/// Returns the system freezable work queue (`system_freezable_wq`).
+///
+/// It is equivalent to the one returned by [`system`] except that it's freezable.
+pub fn system_freezable() -> &'static Queue {
+    // SAFETY: `system_freezable_wq` is a C global, always available.
+    unsafe { &*bindings::system_freezable_wq.cast() }
+}
+
+/// Returns the system power-efficient work queue (`system_power_efficient_wq`).
+///
+/// It is inclined towards saving power and is converted to "unbound" variants if the
+/// `workqueue.power_efficient` kernel parameter is specified; otherwise, it is similar to the one
+/// returned by [`system`].
+pub fn system_power_efficient() -> &'static Queue {
+    // SAFETY: `system_power_efficient_wq` is a C global, always available.
+    unsafe { &*bindings::system_power_efficient_wq.cast() }
+}
+
+/// Returns the system freezable power-efficient work queue (`system_freezable_power_efficient_wq`).
+///
+/// It is similar to the one returned by [`system_power_efficient`] except that is freezable.
+pub fn system_freezable_power_efficient() -> &'static Queue {
+    // SAFETY: `system_freezable_power_efficient_wq` is a C global, always available.
+    unsafe { &*bindings::system_freezable_power_efficient_wq.cast() }
+}
diff --git a/rust/macros/concat_idents.rs b/rust/macros/concat_idents.rs
new file mode 100644
index 000000000000..3b5a9dd70e8a
--- /dev/null
+++ b/rust/macros/concat_idents.rs
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro::{token_stream, Ident, TokenStream, TokenTree};
+
+use crate::helpers::expect_punct;
+
+fn expect_ident(it: &mut token_stream::IntoIter) -> Ident {
+    if let Some(TokenTree::Ident(ident)) = it.next() {
+        ident
+    } else {
+        panic!("Expected Ident")
+    }
+}
+
+pub(crate) fn concat_idents(ts: TokenStream) -> TokenStream {
+    let mut it = ts.into_iter();
+    let a = expect_ident(&mut it);
+    assert_eq!(expect_punct(&mut it), ',');
+    let b = expect_ident(&mut it);
+    assert!(it.next().is_none(), "only two idents can be concatenated");
+    let res = Ident::new(&(a.to_string() + &b.to_string()), b.span());
+    TokenStream::from_iter([TokenTree::Ident(res)])
+}
diff --git a/rust/macros/helpers.rs b/rust/macros/helpers.rs
new file mode 100644
index 000000000000..ad210563e5a6
--- /dev/null
+++ b/rust/macros/helpers.rs
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro::{token_stream, Group, TokenTree};
+
+pub(crate) fn try_ident(it: &mut token_stream::IntoIter) -> Option<String> {
+    if let Some(TokenTree::Ident(ident)) = it.next() {
+        Some(ident.to_string())
+    } else {
+        None
+    }
+}
+
+pub(crate) fn try_literal(it: &mut token_stream::IntoIter) -> Option<String> {
+    if let Some(TokenTree::Literal(literal)) = it.next() {
+        Some(literal.to_string())
+    } else {
+        None
+    }
+}
+
+pub(crate) fn try_byte_string(it: &mut token_stream::IntoIter) -> Option<String> {
+    try_literal(it).and_then(|byte_string| {
+        if byte_string.starts_with("b\"") && byte_string.ends_with('\"') {
+            Some(byte_string[2..byte_string.len() - 1].to_string())
+        } else {
+            None
+        }
+    })
+}
+
+pub(crate) fn expect_ident(it: &mut token_stream::IntoIter) -> String {
+    try_ident(it).expect("Expected Ident")
+}
+
+pub(crate) fn expect_punct(it: &mut token_stream::IntoIter) -> char {
+    if let TokenTree::Punct(punct) = it.next().expect("Reached end of token stream for Punct") {
+        punct.as_char()
+    } else {
+        panic!("Expected Punct");
+    }
+}
+
+pub(crate) fn expect_literal(it: &mut token_stream::IntoIter) -> String {
+    try_literal(it).expect("Expected Literal")
+}
+
+pub(crate) fn expect_group(it: &mut token_stream::IntoIter) -> Group {
+    if let TokenTree::Group(group) = it.next().expect("Reached end of token stream for Group") {
+        group
+    } else {
+        panic!("Expected Group");
+    }
+}
+
+pub(crate) fn expect_byte_string(it: &mut token_stream::IntoIter) -> String {
+    try_byte_string(it).expect("Expected byte string")
+}
+
+pub(crate) fn expect_end(it: &mut token_stream::IntoIter) {
+    if it.next().is_some() {
+        panic!("Expected end");
+    }
+}
+
+pub(crate) fn get_literal(it: &mut token_stream::IntoIter, expected_name: &str) -> String {
+    assert_eq!(expect_ident(it), expected_name);
+    assert_eq!(expect_punct(it), ':');
+    let literal = expect_literal(it);
+    assert_eq!(expect_punct(it), ',');
+    literal
+}
+
+pub(crate) fn get_byte_string(it: &mut token_stream::IntoIter, expected_name: &str) -> String {
+    assert_eq!(expect_ident(it), expected_name);
+    assert_eq!(expect_punct(it), ':');
+    let byte_string = expect_byte_string(it);
+    assert_eq!(expect_punct(it), ',');
+    byte_string
+}
diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs
new file mode 100644
index 000000000000..dfb9b3c6f0dc
--- /dev/null
+++ b/rust/macros/lib.rs
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Crate for all kernel procedural macros.
+
+mod concat_idents;
+mod helpers;
+mod module;
+mod vtable;
+
+use proc_macro::TokenStream;
+
+/// Declares a kernel module.
+///
+/// The `type` argument should be a type which implements the [`Module`]
+/// trait. Also accepts various forms of kernel metadata.
+///
+/// C header: [`include/linux/moduleparam.h`](../../../include/linux/moduleparam.h)
+///
+/// [`Module`]: ../kernel/trait.Module.html
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::prelude::*;
+///
+/// module!{
+///     type: MyModule,
+///     name: b"my_kernel_module",
+///     author: b"Rust for Linux Contributors",
+///     description: b"My very own kernel module!",
+///     license: b"GPL",
+///     params: {
+///        my_i32: i32 {
+///            default: 42,
+///            permissions: 0o000,
+///            description: b"Example of i32",
+///        },
+///        writeable_i32: i32 {
+///            default: 42,
+///            permissions: 0o644,
+///            description: b"Example of i32",
+///        },
+///    },
+/// }
+///
+/// struct MyModule;
+///
+/// impl kernel::Module for MyModule {
+///     fn init() -> Result<Self> {
+///         // If the parameter is writeable, then the kparam lock must be
+///         // taken to read the parameter:
+///         {
+///             let lock = THIS_MODULE.kernel_param_lock();
+///             pr_info!("i32 param is:  {}\n", writeable_i32.read(&lock));
+///         }
+///         // If the parameter is read only, it can be read without locking
+///         // the kernel parameters:
+///         pr_info!("i32 param is:  {}\n", my_i32.read());
+///         Ok(Self)
+///     }
+/// }
+/// ```
+///
+/// # Supported argument types
+///   - `type`: type which implements the [`Module`] trait (required).
+///   - `name`: byte array of the name of the kernel module (required).
+///   - `author`: byte array of the author of the kernel module.
+///   - `description`: byte array of the description of the kernel module.
+///   - `license`: byte array of the license of the kernel module (required).
+///   - `alias`: byte array of alias name of the kernel module.
+///   - `alias_rtnl_link`: byte array of the `rtnl_link_alias` of the kernel module
+///     (mutually exclusive with `alias`).
+///   - `params`: parameters for the kernel module, as described below.
+///
+/// # Supported parameter types
+///
+///   - `bool`: Corresponds to C `bool` param type.
+///   - `i8`: No equivalent C param type.
+///   - `u8`: Corresponds to C `char` param type.
+///   - `i16`: Corresponds to C `short` param type.
+///   - `u16`: Corresponds to C `ushort` param type.
+///   - `i32`: Corresponds to C `int` param type.
+///   - `u32`: Corresponds to C `uint` param type.
+///   - `i64`: No equivalent C param type.
+///   - `u64`: Corresponds to C `ullong` param type.
+///   - `isize`: No equivalent C param type.
+///   - `usize`: No equivalent C param type.
+///   - `str`: Corresponds to C `charp` param type. Reading returns a byte slice.
+///   - `ArrayParam<T,N>`: Corresponds to C parameters created using `module_param_array`.
+///     An array of `T`'s of length at **most** `N`.
+///
+/// `invbool` is unsupported: it was only ever used in a few modules.
+/// Consider using a `bool` and inverting the logic instead.
+#[proc_macro]
+pub fn module(ts: TokenStream) -> TokenStream {
+    module::module(ts)
+}
+
+/// Declares or implements a vtable trait.
+///
+/// Linux's use of pure vtables is very close to Rust traits, but they differ
+/// in how unimplemented functions are represented. In Rust, traits can provide
+/// default implementation for all non-required methods (and the default
+/// implementation could just return `Error::EINVAL`); Linux typically use C
+/// `NULL` pointers to represent these functions.
+///
+/// This attribute is intended to close the gap. Traits can be declared and
+/// implemented with the `#[vtable]` attribute, and a `HAS_*` associated constant
+/// will be generated for each method in the trait, indicating if the implementor
+/// has overridden a method.
+///
+/// This attribute is not needed if all methods are required.
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::prelude::*;
+///
+/// // Declares a `#[vtable]` trait
+/// #[vtable]
+/// pub trait Operations: Send + Sync + Sized {
+///     fn foo(&self) -> Result<()> {
+///         Err(EINVAL)
+///     }
+///
+///     fn bar(&self) -> Result<()> {
+///         Err(EINVAL)
+///     }
+/// }
+///
+/// struct Foo;
+///
+/// // Implements the `#[vtable]` trait
+/// #[vtable]
+/// impl Operations for Foo {
+///     fn foo(&self) -> Result<()> {
+/// #        Err(EINVAL)
+///         // ...
+///     }
+/// }
+///
+/// assert_eq!(<Foo as Operations>::HAS_FOO, true);
+/// assert_eq!(<Foo as Operations>::HAS_BAR, false);
+/// ```
+#[proc_macro_attribute]
+pub fn vtable(attr: TokenStream, ts: TokenStream) -> TokenStream {
+    vtable::vtable(attr, ts)
+}
+
+/// Concatenate two identifiers.
+///
+/// This is useful in macros that need to declare or reference items with names
+/// starting with a fixed prefix and ending in a user specified name. The resulting
+/// identifier has the span of the second argument.
+///
+/// # Examples
+///
+/// ```ignore
+/// use kernel::macro::concat_idents;
+///
+/// macro_rules! pub_no_prefix {
+///     ($prefix:ident, $($newname:ident),+) => {
+///         $(pub(crate) const $newname: u32 = kernel::macros::concat_idents!($prefix, $newname);)+
+///     };
+/// }
+///
+/// pub_no_prefix!(
+///     binder_driver_return_protocol_,
+///     BR_OK,
+///     BR_ERROR,
+///     BR_TRANSACTION,
+///     BR_REPLY,
+///     BR_DEAD_REPLY,
+///     BR_TRANSACTION_COMPLETE,
+///     BR_INCREFS,
+///     BR_ACQUIRE,
+///     BR_RELEASE,
+///     BR_DECREFS,
+///     BR_NOOP,
+///     BR_SPAWN_LOOPER,
+///     BR_DEAD_BINDER,
+///     BR_CLEAR_DEATH_NOTIFICATION_DONE,
+///     BR_FAILED_REPLY
+/// );
+///
+/// assert_eq!(BR_OK, binder_driver_return_protocol_BR_OK);
+/// ```
+#[proc_macro]
+pub fn concat_idents(ts: TokenStream) -> TokenStream {
+    concat_idents::concat_idents(ts)
+}
diff --git a/rust/macros/module.rs b/rust/macros/module.rs
new file mode 100644
index 000000000000..4e68cf63a2cc
--- /dev/null
+++ b/rust/macros/module.rs
@@ -0,0 +1,655 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro::{token_stream, Delimiter, Group, Literal, TokenStream, TokenTree};
+use std::fmt::Write;
+
+use crate::helpers::*;
+
+#[derive(Clone, PartialEq)]
+enum ParamType {
+    Ident(String),
+    Array { vals: String, max_length: usize },
+}
+
+fn expect_array_fields(it: &mut token_stream::IntoIter) -> ParamType {
+    assert_eq!(expect_punct(it), '<');
+    let vals = expect_ident(it);
+    assert_eq!(expect_punct(it), ',');
+    let max_length_str = expect_literal(it);
+    let max_length = max_length_str
+        .parse::<usize>()
+        .expect("Expected usize length");
+    assert_eq!(expect_punct(it), '>');
+    ParamType::Array { vals, max_length }
+}
+
+fn expect_type(it: &mut token_stream::IntoIter) -> ParamType {
+    if let TokenTree::Ident(ident) = it
+        .next()
+        .expect("Reached end of token stream for param type")
+    {
+        match ident.to_string().as_ref() {
+            "ArrayParam" => expect_array_fields(it),
+            _ => ParamType::Ident(ident.to_string()),
+        }
+    } else {
+        panic!("Expected Param Type")
+    }
+}
+
+struct ModInfoBuilder<'a> {
+    module: &'a str,
+    counter: usize,
+    buffer: String,
+}
+
+impl<'a> ModInfoBuilder<'a> {
+    fn new(module: &'a str) -> Self {
+        ModInfoBuilder {
+            module,
+            counter: 0,
+            buffer: String::new(),
+        }
+    }
+
+    fn emit_base(&mut self, field: &str, content: &str, builtin: bool) {
+        let string = if builtin {
+            // Built-in modules prefix their modinfo strings by `module.`.
+            format!(
+                "{module}.{field}={content}\0",
+                module = self.module,
+                field = field,
+                content = content
+            )
+        } else {
+            // Loadable modules' modinfo strings go as-is.
+            format!("{field}={content}\0", field = field, content = content)
+        };
+
+        write!(
+            &mut self.buffer,
+            "
+                {cfg}
+                #[doc(hidden)]
+                #[link_section = \".modinfo\"]
+                #[used]
+                pub static __{module}_{counter}: [u8; {length}] = *{string};
+            ",
+            cfg = if builtin {
+                "#[cfg(not(MODULE))]"
+            } else {
+                "#[cfg(MODULE)]"
+            },
+            module = self.module.to_uppercase(),
+            counter = self.counter,
+            length = string.len(),
+            string = Literal::byte_string(string.as_bytes()),
+        )
+        .unwrap();
+
+        self.counter += 1;
+    }
+
+    fn emit_only_builtin(&mut self, field: &str, content: &str) {
+        self.emit_base(field, content, true)
+    }
+
+    fn emit_only_loadable(&mut self, field: &str, content: &str) {
+        self.emit_base(field, content, false)
+    }
+
+    fn emit(&mut self, field: &str, content: &str) {
+        self.emit_only_builtin(field, content);
+        self.emit_only_loadable(field, content);
+    }
+
+    fn emit_param(&mut self, field: &str, param: &str, content: &str) {
+        let content = format!("{param}:{content}", param = param, content = content);
+        self.emit(field, &content);
+    }
+}
+
+fn permissions_are_readonly(perms: &str) -> bool {
+    let (radix, digits) = if let Some(n) = perms.strip_prefix("0x") {
+        (16, n)
+    } else if let Some(n) = perms.strip_prefix("0o") {
+        (8, n)
+    } else if let Some(n) = perms.strip_prefix("0b") {
+        (2, n)
+    } else {
+        (10, perms)
+    };
+    match u32::from_str_radix(digits, radix) {
+        Ok(perms) => perms & 0o222 == 0,
+        Err(_) => false,
+    }
+}
+
+fn param_ops_path(param_type: &str) -> &'static str {
+    match param_type {
+        "bool" => "kernel::module_param::PARAM_OPS_BOOL",
+        "i8" => "kernel::module_param::PARAM_OPS_I8",
+        "u8" => "kernel::module_param::PARAM_OPS_U8",
+        "i16" => "kernel::module_param::PARAM_OPS_I16",
+        "u16" => "kernel::module_param::PARAM_OPS_U16",
+        "i32" => "kernel::module_param::PARAM_OPS_I32",
+        "u32" => "kernel::module_param::PARAM_OPS_U32",
+        "i64" => "kernel::module_param::PARAM_OPS_I64",
+        "u64" => "kernel::module_param::PARAM_OPS_U64",
+        "isize" => "kernel::module_param::PARAM_OPS_ISIZE",
+        "usize" => "kernel::module_param::PARAM_OPS_USIZE",
+        "str" => "kernel::module_param::PARAM_OPS_STR",
+        t => panic!("Unrecognized type {}", t),
+    }
+}
+
+fn try_simple_param_val(
+    param_type: &str,
+) -> Box<dyn Fn(&mut token_stream::IntoIter) -> Option<String>> {
+    match param_type {
+        "bool" => Box::new(try_ident),
+        "str" => Box::new(|param_it| {
+            try_byte_string(param_it)
+                .map(|s| format!("kernel::module_param::StringParam::Ref(b\"{}\")", s))
+        }),
+        _ => Box::new(try_literal),
+    }
+}
+
+fn get_default(param_type: &ParamType, param_it: &mut token_stream::IntoIter) -> String {
+    let try_param_val = match param_type {
+        ParamType::Ident(ref param_type)
+        | ParamType::Array {
+            vals: ref param_type,
+            max_length: _,
+        } => try_simple_param_val(param_type),
+    };
+    assert_eq!(expect_ident(param_it), "default");
+    assert_eq!(expect_punct(param_it), ':');
+    let default = match param_type {
+        ParamType::Ident(_) => try_param_val(param_it).expect("Expected default param value"),
+        ParamType::Array {
+            vals: _,
+            max_length: _,
+        } => {
+            let group = expect_group(param_it);
+            assert_eq!(group.delimiter(), Delimiter::Bracket);
+            let mut default_vals = Vec::new();
+            let mut it = group.stream().into_iter();
+
+            while let Some(default_val) = try_param_val(&mut it) {
+                default_vals.push(default_val);
+                match it.next() {
+                    Some(TokenTree::Punct(punct)) => assert_eq!(punct.as_char(), ','),
+                    None => break,
+                    _ => panic!("Expected ',' or end of array default values"),
+                }
+            }
+
+            let mut default_array = "kernel::module_param::ArrayParam::create(&[".to_string();
+            default_array.push_str(
+                &default_vals
+                    .iter()
+                    .map(|val| val.to_string())
+                    .collect::<Vec<String>>()
+                    .join(","),
+            );
+            default_array.push_str("])");
+            default_array
+        }
+    };
+    assert_eq!(expect_punct(param_it), ',');
+    default
+}
+
+fn generated_array_ops_name(vals: &str, max_length: usize) -> String {
+    format!(
+        "__generated_array_ops_{vals}_{max_length}",
+        vals = vals,
+        max_length = max_length
+    )
+}
+
+#[derive(Debug, Default)]
+struct ModuleInfo {
+    type_: String,
+    license: String,
+    name: String,
+    author: Option<String>,
+    description: Option<String>,
+    alias: Option<String>,
+    params: Option<Group>,
+}
+
+impl ModuleInfo {
+    fn parse(it: &mut token_stream::IntoIter) -> Self {
+        let mut info = ModuleInfo::default();
+
+        const EXPECTED_KEYS: &[&str] = &[
+            "type",
+            "name",
+            "author",
+            "description",
+            "license",
+            "alias",
+            "alias_rtnl_link",
+            "params",
+        ];
+        const REQUIRED_KEYS: &[&str] = &["type", "name", "license"];
+        let mut seen_keys = Vec::new();
+
+        loop {
+            let key = match it.next() {
+                Some(TokenTree::Ident(ident)) => ident.to_string(),
+                Some(_) => panic!("Expected Ident or end"),
+                None => break,
+            };
+
+            if seen_keys.contains(&key) {
+                panic!(
+                    "Duplicated key \"{}\". Keys can only be specified once.",
+                    key
+                );
+            }
+
+            assert_eq!(expect_punct(it), ':');
+
+            match key.as_str() {
+                "type" => info.type_ = expect_ident(it),
+                "name" => info.name = expect_byte_string(it),
+                "author" => info.author = Some(expect_byte_string(it)),
+                "description" => info.description = Some(expect_byte_string(it)),
+                "license" => info.license = expect_byte_string(it),
+                "alias" => info.alias = Some(expect_byte_string(it)),
+                "alias_rtnl_link" => {
+                    info.alias = Some(format!("rtnl-link-{}", expect_byte_string(it)))
+                }
+                "params" => info.params = Some(expect_group(it)),
+                _ => panic!(
+                    "Unknown key \"{}\". Valid keys are: {:?}.",
+                    key, EXPECTED_KEYS
+                ),
+            }
+
+            assert_eq!(expect_punct(it), ',');
+
+            seen_keys.push(key);
+        }
+
+        expect_end(it);
+
+        for key in REQUIRED_KEYS {
+            if !seen_keys.iter().any(|e| e == key) {
+                panic!("Missing required key \"{}\".", key);
+            }
+        }
+
+        let mut ordered_keys: Vec<&str> = Vec::new();
+        for key in EXPECTED_KEYS {
+            if seen_keys.iter().any(|e| e == key) {
+                ordered_keys.push(key);
+            }
+        }
+
+        if seen_keys != ordered_keys {
+            panic!(
+                "Keys are not ordered as expected. Order them like: {:?}.",
+                ordered_keys
+            );
+        }
+
+        info
+    }
+}
+
+pub(crate) fn module(ts: TokenStream) -> TokenStream {
+    let mut it = ts.into_iter();
+
+    let info = ModuleInfo::parse(&mut it);
+
+    let mut modinfo = ModInfoBuilder::new(info.name.as_ref());
+    if let Some(author) = info.author {
+        modinfo.emit("author", &author);
+    }
+    if let Some(description) = info.description {
+        modinfo.emit("description", &description);
+    }
+    modinfo.emit("license", &info.license);
+    if let Some(alias) = info.alias {
+        modinfo.emit("alias", &alias);
+    }
+
+    // Built-in modules also export the `file` modinfo string.
+    let file =
+        std::env::var("RUST_MODFILE").expect("Unable to fetch RUST_MODFILE environmental variable");
+    modinfo.emit_only_builtin("file", &file);
+
+    let mut array_types_to_generate = Vec::new();
+    if let Some(params) = info.params {
+        assert_eq!(params.delimiter(), Delimiter::Brace);
+
+        let mut it = params.stream().into_iter();
+
+        loop {
+            let param_name = match it.next() {
+                Some(TokenTree::Ident(ident)) => ident.to_string(),
+                Some(_) => panic!("Expected Ident or end"),
+                None => break,
+            };
+
+            assert_eq!(expect_punct(&mut it), ':');
+            let param_type = expect_type(&mut it);
+            let group = expect_group(&mut it);
+            assert_eq!(expect_punct(&mut it), ',');
+
+            assert_eq!(group.delimiter(), Delimiter::Brace);
+
+            let mut param_it = group.stream().into_iter();
+            let param_default = get_default(&param_type, &mut param_it);
+            let param_permissions = get_literal(&mut param_it, "permissions");
+            let param_description = get_byte_string(&mut param_it, "description");
+            expect_end(&mut param_it);
+
+            // TODO: More primitive types.
+            // TODO: Other kinds: unsafes, etc.
+            let (param_kernel_type, ops): (String, _) = match param_type {
+                ParamType::Ident(ref param_type) => (
+                    param_type.to_string(),
+                    param_ops_path(param_type).to_string(),
+                ),
+                ParamType::Array {
+                    ref vals,
+                    max_length,
+                } => {
+                    array_types_to_generate.push((vals.clone(), max_length));
+                    (
+                        format!("__rust_array_param_{}_{}", vals, max_length),
+                        generated_array_ops_name(vals, max_length),
+                    )
+                }
+            };
+
+            modinfo.emit_param("parmtype", &param_name, &param_kernel_type);
+            modinfo.emit_param("parm", &param_name, &param_description);
+            let param_type_internal = match param_type {
+                ParamType::Ident(ref param_type) => match param_type.as_ref() {
+                    "str" => "kernel::module_param::StringParam".to_string(),
+                    other => other.to_string(),
+                },
+                ParamType::Array {
+                    ref vals,
+                    max_length,
+                } => format!(
+                    "kernel::module_param::ArrayParam<{vals}, {max_length}>",
+                    vals = vals,
+                    max_length = max_length
+                ),
+            };
+            let read_func = if permissions_are_readonly(&param_permissions) {
+                format!(
+                    "
+                        fn read(&self)
+                            -> &<{param_type_internal} as kernel::module_param::ModuleParam>::Value {{
+                            // SAFETY: Parameters do not need to be locked because they are
+                            // read only or sysfs is not enabled.
+                            unsafe {{
+                                <{param_type_internal} as kernel::module_param::ModuleParam>::value(
+                                    &__{name}_{param_name}_value
+                                )
+                            }}
+                        }}
+                    ",
+                    name = info.name,
+                    param_name = param_name,
+                    param_type_internal = param_type_internal,
+                )
+            } else {
+                format!(
+                    "
+                        fn read<'lck>(&self, lock: &'lck kernel::KParamGuard)
+                            -> &'lck <{param_type_internal} as kernel::module_param::ModuleParam>::Value {{
+                            // SAFETY: Parameters are locked by `KParamGuard`.
+                            unsafe {{
+                                <{param_type_internal} as kernel::module_param::ModuleParam>::value(
+                                    &__{name}_{param_name}_value
+                                )
+                            }}
+                        }}
+                    ",
+                    name = info.name,
+                    param_name = param_name,
+                    param_type_internal = param_type_internal,
+                )
+            };
+            let kparam = format!(
+                "
+                    kernel::bindings::kernel_param__bindgen_ty_1 {{
+                        arg: unsafe {{ &__{name}_{param_name}_value }}
+                            as *const _ as *mut core::ffi::c_void,
+                    }},
+                ",
+                name = info.name,
+                param_name = param_name,
+            );
+            write!(
+                modinfo.buffer,
+                "
+                static mut __{name}_{param_name}_value: {param_type_internal} = {param_default};
+
+                struct __{name}_{param_name};
+
+                impl __{name}_{param_name} {{ {read_func} }}
+
+                const {param_name}: __{name}_{param_name} = __{name}_{param_name};
+
+                // Note: the C macro that generates the static structs for the `__param` section
+                // asks for them to be `aligned(sizeof(void *))`. However, that was put in place
+                // in 2003 in commit 38d5b085d2a0 (\"[PATCH] Fix over-alignment problem on x86-64\")
+                // to undo GCC over-alignment of static structs of >32 bytes. It seems that is
+                // not the case anymore, so we simplify to a transparent representation here
+                // in the expectation that it is not needed anymore.
+                // TODO: Revisit this to confirm the above comment and remove it if it happened.
+                #[repr(transparent)]
+                struct __{name}_{param_name}_RacyKernelParam(kernel::bindings::kernel_param);
+
+                unsafe impl Sync for __{name}_{param_name}_RacyKernelParam {{
+                }}
+
+                #[cfg(not(MODULE))]
+                const __{name}_{param_name}_name: *const core::ffi::c_char =
+                    b\"{name}.{param_name}\\0\" as *const _ as *const core::ffi::c_char;
+
+                #[cfg(MODULE)]
+                const __{name}_{param_name}_name: *const core::ffi::c_char =
+                    b\"{param_name}\\0\" as *const _ as *const core::ffi::c_char;
+
+                #[link_section = \"__param\"]
+                #[used]
+                static __{name}_{param_name}_struct: __{name}_{param_name}_RacyKernelParam =
+                    __{name}_{param_name}_RacyKernelParam(kernel::bindings::kernel_param {{
+                        name: __{name}_{param_name}_name,
+                        // SAFETY: `__this_module` is constructed by the kernel at load time
+                        // and will not be freed until the module is unloaded.
+                        #[cfg(MODULE)]
+                        mod_: unsafe {{ &kernel::bindings::__this_module as *const _ as *mut _ }},
+                        #[cfg(not(MODULE))]
+                        mod_: core::ptr::null_mut(),
+                        ops: unsafe {{ &{ops} }} as *const kernel::bindings::kernel_param_ops,
+                        perm: {permissions},
+                        level: -1,
+                        flags: 0,
+                        __bindgen_anon_1: {kparam}
+                    }});
+                ",
+                name = info.name,
+                param_type_internal = param_type_internal,
+                read_func = read_func,
+                param_default = param_default,
+                param_name = param_name,
+                ops = ops,
+                permissions = param_permissions,
+                kparam = kparam,
+            )
+            .unwrap();
+        }
+    }
+
+    let mut generated_array_types = String::new();
+
+    for (vals, max_length) in array_types_to_generate {
+        let ops_name = generated_array_ops_name(&vals, max_length);
+        write!(
+            generated_array_types,
+            "
+                kernel::make_param_ops!(
+                    {ops_name},
+                    kernel::module_param::ArrayParam<{vals}, {{ {max_length} }}>
+                );
+            ",
+            ops_name = ops_name,
+            vals = vals,
+            max_length = max_length,
+        )
+        .unwrap();
+    }
+
+    format!(
+        "
+            /// The module name.
+            ///
+            /// Used by the printing macros, e.g. [`info!`].
+            const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
+
+            /// The \"Rust loadable module\" mark, for `scripts/is_rust_module.sh`.
+            //
+            // This may be best done another way later on, e.g. as a new modinfo
+            // key or a new section. For the moment, keep it simple.
+            #[cfg(MODULE)]
+            #[doc(hidden)]
+            #[used]
+            static __IS_RUST_MODULE: () = ();
+
+            static mut __MOD: Option<{type_}> = None;
+
+            // SAFETY: `__this_module` is constructed by the kernel at load time and will not be
+            // freed until the module is unloaded.
+            #[cfg(MODULE)]
+            static THIS_MODULE: kernel::ThisModule = unsafe {{
+                kernel::ThisModule::from_ptr(&kernel::bindings::__this_module as *const _ as *mut _)
+            }};
+            #[cfg(not(MODULE))]
+            static THIS_MODULE: kernel::ThisModule = unsafe {{
+                kernel::ThisModule::from_ptr(core::ptr::null_mut())
+            }};
+
+            // Loadable modules need to export the `{{init,cleanup}}_module` identifiers.
+            #[cfg(MODULE)]
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern \"C\" fn init_module() -> core::ffi::c_int {{
+                __init()
+            }}
+
+            #[cfg(MODULE)]
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern \"C\" fn cleanup_module() {{
+                __exit()
+            }}
+
+            // Built-in modules are initialized through an initcall pointer
+            // and the identifiers need to be unique.
+            #[cfg(not(MODULE))]
+            #[cfg(not(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS))]
+            #[doc(hidden)]
+            #[link_section = \"{initcall_section}\"]
+            #[used]
+            pub static __{name}_initcall: extern \"C\" fn() -> core::ffi::c_int = __{name}_init;
+
+            #[cfg(not(MODULE))]
+            #[cfg(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)]
+            core::arch::global_asm!(
+                r#\".section \"{initcall_section}\", \"a\"
+                __{name}_initcall:
+                    .long   __{name}_init - .
+                    .previous
+                \"#
+            );
+
+            #[cfg(not(MODULE))]
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern \"C\" fn __{name}_init() -> core::ffi::c_int {{
+                __init()
+            }}
+
+            #[cfg(not(MODULE))]
+            #[doc(hidden)]
+            #[no_mangle]
+            pub extern \"C\" fn __{name}_exit() {{
+                __exit()
+            }}
+
+            fn __init() -> core::ffi::c_int {{
+                match <{type_} as kernel::Module>::init(kernel::c_str!(\"{name}\"), &THIS_MODULE) {{
+                    Ok(m) => {{
+                        unsafe {{
+                            __MOD = Some(m);
+                        }}
+                        return 0;
+                    }}
+                    Err(e) => {{
+                        return e.to_kernel_errno();
+                    }}
+                }}
+            }}
+
+            fn __exit() {{
+                unsafe {{
+                    // Invokes `drop()` on `__MOD`, which should be used for cleanup.
+                    __MOD = None;
+                }}
+            }}
+
+            {modinfo}
+
+            {generated_array_types}
+        ",
+        type_ = info.type_,
+        name = info.name,
+        modinfo = modinfo.buffer,
+        generated_array_types = generated_array_types,
+        initcall_section = ".initcall6.init"
+    )
+    .parse()
+    .expect("Error parsing formatted string into token stream.")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_permissions_are_readonly() {
+        assert!(permissions_are_readonly("0b000000000"));
+        assert!(permissions_are_readonly("0o000"));
+        assert!(permissions_are_readonly("000"));
+        assert!(permissions_are_readonly("0x000"));
+
+        assert!(!permissions_are_readonly("0b111111111"));
+        assert!(!permissions_are_readonly("0o777"));
+        assert!(!permissions_are_readonly("511"));
+        assert!(!permissions_are_readonly("0x1ff"));
+
+        assert!(permissions_are_readonly("0o014"));
+        assert!(permissions_are_readonly("0o015"));
+
+        assert!(!permissions_are_readonly("0o214"));
+        assert!(!permissions_are_readonly("0o024"));
+        assert!(!permissions_are_readonly("0o012"));
+
+        assert!(!permissions_are_readonly("0o315"));
+        assert!(!permissions_are_readonly("0o065"));
+        assert!(!permissions_are_readonly("0o017"));
+    }
+}
diff --git a/rust/macros/vtable.rs b/rust/macros/vtable.rs
new file mode 100644
index 000000000000..34d5e7fb5768
--- /dev/null
+++ b/rust/macros/vtable.rs
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+
+use proc_macro::{Delimiter, Group, TokenStream, TokenTree};
+use std::collections::HashSet;
+use std::fmt::Write;
+
+pub(crate) fn vtable(_attr: TokenStream, ts: TokenStream) -> TokenStream {
+    let mut tokens: Vec<_> = ts.into_iter().collect();
+
+    // Scan for the `trait` or `impl` keyword.
+    let is_trait = tokens
+        .iter()
+        .find_map(|token| match token {
+            TokenTree::Ident(ident) => match ident.to_string().as_str() {
+                "trait" => Some(true),
+                "impl" => Some(false),
+                _ => None,
+            },
+            _ => None,
+        })
+        .expect("#[vtable] attribute should only be applied to trait or impl block");
+
+    // Retrieve the main body. The main body should be the last token tree.
+    let body = match tokens.pop() {
+        Some(TokenTree::Group(group)) if group.delimiter() == Delimiter::Brace => group,
+        _ => panic!("cannot locate main body of trait or impl block"),
+    };
+
+    let mut body_it = body.stream().into_iter();
+    let mut functions = Vec::new();
+    let mut consts = HashSet::new();
+    while let Some(token) = body_it.next() {
+        match token {
+            TokenTree::Ident(ident) if ident.to_string() == "fn" => {
+                let fn_name = match body_it.next() {
+                    Some(TokenTree::Ident(ident)) => ident.to_string(),
+                    // Possibly we've encountered a fn pointer type instead.
+                    _ => continue,
+                };
+                functions.push(fn_name);
+            }
+            TokenTree::Ident(ident) if ident.to_string() == "const" => {
+                let const_name = match body_it.next() {
+                    Some(TokenTree::Ident(ident)) => ident.to_string(),
+                    // Possibly we've encountered an inline const block instead.
+                    _ => continue,
+                };
+                consts.insert(const_name);
+            }
+            _ => (),
+        }
+    }
+
+    let mut const_items;
+    if is_trait {
+        const_items = "
+                /// A marker to prevent implementors from forgetting to use [`#[vtable]`](vtable)
+                /// attribute when implementing this trait.
+                const USE_VTABLE_ATTR: ();
+        "
+        .to_owned();
+
+        for f in functions {
+            let gen_const_name = format!("HAS_{}", f.to_uppercase());
+            // Skip if it's declared already -- this allows user override.
+            if consts.contains(&gen_const_name) {
+                continue;
+            }
+            // We don't know on the implementation-site whether a method is required or provided
+            // so we have to generate a const for all methods.
+            write!(
+                const_items,
+                "/// Indicates if the `{f}` method is overridden by the implementor.
+                const {gen_const_name}: bool = false;",
+            )
+            .unwrap();
+        }
+    } else {
+        const_items = "const USE_VTABLE_ATTR: () = ();".to_owned();
+
+        for f in functions {
+            let gen_const_name = format!("HAS_{}", f.to_uppercase());
+            if consts.contains(&gen_const_name) {
+                continue;
+            }
+            write!(const_items, "const {gen_const_name}: bool = true;").unwrap();
+        }
+    }
+
+    let new_body = vec![const_items.parse().unwrap(), body.stream()]
+        .into_iter()
+        .collect();
+    tokens.push(TokenTree::Group(Group::new(Delimiter::Brace, new_body)));
+    tokens.into_iter().collect()
+}
diff --git a/samples/Kconfig b/samples/Kconfig
index 470ee3baf2e1..0d81c00289ee 100644
--- a/samples/Kconfig
+++ b/samples/Kconfig
@@ -263,6 +263,8 @@ config SAMPLE_CORESIGHT_SYSCFG
 	  This demonstrates how a user may create their own CoreSight
 	  configurations and easily load them into the system at runtime.
 
+source "samples/rust/Kconfig"
+
 endif # SAMPLES
 
 config HAVE_SAMPLE_FTRACE_DIRECT
diff --git a/samples/Makefile b/samples/Makefile
index 701e912ab5af..9832ef3f8fcb 100644
--- a/samples/Makefile
+++ b/samples/Makefile
@@ -35,3 +35,4 @@ subdir-$(CONFIG_SAMPLE_WATCH_QUEUE)	+= watch_queue
 obj-$(CONFIG_DEBUG_KMEMLEAK_TEST)	+= kmemleak/
 obj-$(CONFIG_SAMPLE_CORESIGHT_SYSCFG)	+= coresight/
 obj-$(CONFIG_SAMPLE_FPROBE)		+= fprobe/
+obj-$(CONFIG_SAMPLES_RUST)		+= rust/
diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig
new file mode 100644
index 000000000000..861b35318b4d
--- /dev/null
+++ b/samples/rust/Kconfig
@@ -0,0 +1,165 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menuconfig SAMPLES_RUST
+	bool "Rust samples"
+	depends on RUST
+	help
+	  You can build sample Rust kernel code here.
+
+	  If unsure, say N.
+
+if SAMPLES_RUST
+
+config SAMPLE_RUST_MINIMAL
+	tristate "Minimal"
+	help
+	  This option builds the Rust minimal module sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_minimal.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_PRINT
+	tristate "Printing macros"
+	help
+	  This option builds the Rust printing macros sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_print.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_MODULE_PARAMETERS
+	tristate "Module parameters"
+	help
+	  This option builds the Rust module parameters sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_module_parameters.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_SYNC
+	tristate "Synchronisation primitives"
+	help
+	  This option builds the Rust synchronisation primitives sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_sync.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_CHRDEV
+	tristate "Character device"
+	help
+	  This option builds the Rust character device sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_chrdev.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_MISCDEV
+	tristate "Miscellaneous device"
+	help
+	  This option builds the Rust miscellaneous device sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_miscdev.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_STACK_PROBING
+	tristate "Stack probing"
+	help
+	  This option builds the Rust stack probing sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_stack_probing.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_SEMAPHORE
+	tristate "Semaphore"
+	help
+	  This option builds the Rust semaphore sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_semaphore.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_SEMAPHORE_C
+	tristate "Semaphore (in C, for comparison)"
+	help
+	  This option builds the Rust semaphore sample (in C, for comparison).
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_semaphore_c.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_RANDOM
+	tristate "Random"
+	help
+	  This option builds the Rust random sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_random.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_PLATFORM
+	tristate "Platform device driver"
+	help
+	  This option builds the Rust platform device driver sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_platform.
+
+config SAMPLE_RUST_FS
+	tristate "File system"
+	help
+	  This option builds the Rust file system sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_fs.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_NETFILTER
+	tristate "Network filter module"
+	help
+	  This option builds the Rust netfilter module sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_netfilter.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_ECHO_SERVER
+	tristate "Echo server module"
+	help
+	  This option builds the Rust echo server  module sample.
+
+	  To compile this as a module, choose M here:
+	  the module will be called rust_echo_server.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_HOSTPROGS
+	bool "Host programs"
+	help
+	  This option builds the Rust host program samples.
+
+	  If unsure, say N.
+
+config SAMPLE_RUST_SELFTESTS
+	tristate "Self tests"
+	help
+	  This option builds the self test cases for Rust.
+
+	  If unsure, say N.
+
+endif # SAMPLES_RUST
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
new file mode 100644
index 000000000000..420bcefeb082
--- /dev/null
+++ b/samples/rust/Makefile
@@ -0,0 +1,19 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o
+obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_MODULE_PARAMETERS)	+= rust_module_parameters.o
+obj-$(CONFIG_SAMPLE_RUST_SYNC)			+= rust_sync.o
+obj-$(CONFIG_SAMPLE_RUST_CHRDEV)		+= rust_chrdev.o
+obj-$(CONFIG_SAMPLE_RUST_MISCDEV)		+= rust_miscdev.o
+obj-$(CONFIG_SAMPLE_RUST_STACK_PROBING)		+= rust_stack_probing.o
+obj-$(CONFIG_SAMPLE_RUST_SEMAPHORE)		+= rust_semaphore.o
+obj-$(CONFIG_SAMPLE_RUST_SEMAPHORE_C)		+= rust_semaphore_c.o
+obj-$(CONFIG_SAMPLE_RUST_RANDOM)		+= rust_random.o
+obj-$(CONFIG_SAMPLE_RUST_PLATFORM)		+= rust_platform.o
+obj-$(CONFIG_SAMPLE_RUST_NETFILTER)		+= rust_netfilter.o
+obj-$(CONFIG_SAMPLE_RUST_ECHO_SERVER)		+= rust_echo_server.o
+obj-$(CONFIG_SAMPLE_RUST_FS)			+= rust_fs.o
+obj-$(CONFIG_SAMPLE_RUST_SELFTESTS)		+= rust_selftests.o
+
+subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)		+= hostprogs
diff --git a/samples/rust/hostprogs/.gitignore b/samples/rust/hostprogs/.gitignore
new file mode 100644
index 000000000000..a6c173da5048
--- /dev/null
+++ b/samples/rust/hostprogs/.gitignore
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+single
diff --git a/samples/rust/hostprogs/Makefile b/samples/rust/hostprogs/Makefile
new file mode 100644
index 000000000000..8ddcbd7416db
--- /dev/null
+++ b/samples/rust/hostprogs/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+hostprogs-always-y := single
+
+single-rust := y
diff --git a/samples/rust/hostprogs/a.rs b/samples/rust/hostprogs/a.rs
new file mode 100644
index 000000000000..f7a4a3d0f4e0
--- /dev/null
+++ b/samples/rust/hostprogs/a.rs
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust single host program sample: module `a`.
+
+pub(crate) fn f(x: i32) {
+    println!("The number is {}.", x);
+}
diff --git a/samples/rust/hostprogs/b.rs b/samples/rust/hostprogs/b.rs
new file mode 100644
index 000000000000..c1675890648f
--- /dev/null
+++ b/samples/rust/hostprogs/b.rs
@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust single host program sample: module `b`.
+
+pub(crate) const CONSTANT: i32 = 42;
diff --git a/samples/rust/hostprogs/single.rs b/samples/rust/hostprogs/single.rs
new file mode 100644
index 000000000000..8c48a119339a
--- /dev/null
+++ b/samples/rust/hostprogs/single.rs
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust single host program sample.
+
+mod a;
+mod b;
+
+fn main() {
+    println!("Hello world!");
+
+    a::f(b::CONSTANT);
+}
diff --git a/samples/rust/rust_chrdev.rs b/samples/rust/rust_chrdev.rs
new file mode 100644
index 000000000000..52f6e652d1a6
--- /dev/null
+++ b/samples/rust/rust_chrdev.rs
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust character device sample.
+
+use kernel::prelude::*;
+use kernel::{chrdev, file};
+
+module! {
+    type: RustChrdev,
+    name: b"rust_chrdev",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust character device sample",
+    license: b"GPL",
+}
+
+struct RustFile;
+
+#[vtable]
+impl file::Operations for RustFile {
+    fn open(_shared: &(), _file: &file::File) -> Result {
+        Ok(())
+    }
+}
+
+struct RustChrdev {
+    _dev: Pin<Box<chrdev::Registration<2>>>,
+}
+
+impl kernel::Module for RustChrdev {
+    fn init(name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust character device sample (init)\n");
+
+        let mut chrdev_reg = chrdev::Registration::new_pinned(name, 0, module)?;
+
+        // Register the same kind of device twice, we're just demonstrating
+        // that you can use multiple minors. There are two minors in this case
+        // because its type is `chrdev::Registration<2>`
+        chrdev_reg.as_mut().register::<RustFile>()?;
+        chrdev_reg.as_mut().register::<RustFile>()?;
+
+        Ok(RustChrdev { _dev: chrdev_reg })
+    }
+}
+
+impl Drop for RustChrdev {
+    fn drop(&mut self) {
+        pr_info!("Rust character device sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_echo_server.rs b/samples/rust/rust_echo_server.rs
new file mode 100644
index 000000000000..5fc802f4dc33
--- /dev/null
+++ b/samples/rust/rust_echo_server.rs
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust echo server sample.
+
+use kernel::{
+    kasync::executor::{workqueue::Executor as WqExecutor, AutoStopHandle, Executor},
+    kasync::net::{TcpListener, TcpStream},
+    net::{self, Ipv4Addr, SocketAddr, SocketAddrV4},
+    prelude::*,
+    spawn_task,
+    sync::{Ref, RefBorrow},
+};
+
+async fn echo_server(stream: TcpStream) -> Result {
+    let mut buf = [0u8; 1024];
+    loop {
+        let n = stream.read(&mut buf).await?;
+        if n == 0 {
+            return Ok(());
+        }
+        stream.write_all(&buf[..n]).await?;
+    }
+}
+
+async fn accept_loop(listener: TcpListener, executor: Ref<impl Executor>) {
+    loop {
+        if let Ok(stream) = listener.accept().await {
+            let _ = spawn_task!(executor.as_ref_borrow(), echo_server(stream));
+        }
+    }
+}
+
+fn start_listener(ex: RefBorrow<'_, impl Executor + Send + Sync + 'static>) -> Result {
+    let addr = SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::ANY, 8080));
+    let listener = TcpListener::try_new(net::init_ns(), &addr)?;
+    spawn_task!(ex, accept_loop(listener, ex.into()))?;
+    Ok(())
+}
+
+struct RustEchoServer {
+    _handle: AutoStopHandle<dyn Executor>,
+}
+
+impl kernel::Module for RustEchoServer {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        let handle = WqExecutor::try_new(kernel::workqueue::system())?;
+        start_listener(handle.executor())?;
+        Ok(Self {
+            _handle: handle.into(),
+        })
+    }
+}
+
+module! {
+    type: RustEchoServer,
+    name: b"rust_echo_server",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust tcp echo sample",
+    license: b"GPL v2",
+}
diff --git a/samples/rust/rust_fs.rs b/samples/rust/rust_fs.rs
new file mode 100644
index 000000000000..d286b396dd17
--- /dev/null
+++ b/samples/rust/rust_fs.rs
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust file system sample.
+
+use kernel::prelude::*;
+use kernel::{c_str, fs};
+
+module_fs! {
+    type: RustFs,
+    name: b"rust_fs",
+    author: b"Rust for Linux Contributors",
+    license: b"GPL",
+}
+
+struct RustFs;
+
+#[vtable]
+impl fs::Context<Self> for RustFs {
+    type Data = ();
+
+    kernel::define_fs_params! {(),
+        {flag, "flag", |_, v| { pr_info!("flag passed-in: {v}\n"); Ok(()) } },
+        {flag_no, "flagno", |_, v| { pr_info!("flagno passed-in: {v}\n"); Ok(()) } },
+        {bool, "bool", |_, v| { pr_info!("bool passed-in: {v}\n"); Ok(()) } },
+        {u32, "u32", |_, v| { pr_info!("u32 passed-in: {v}\n"); Ok(()) } },
+        {u32oct, "u32oct", |_, v| { pr_info!("u32oct passed-in: {v}\n"); Ok(()) } },
+        {u32hex, "u32hex", |_, v| { pr_info!("u32hex passed-in: {v}\n"); Ok(()) } },
+        {s32, "s32", |_, v| { pr_info!("s32 passed-in: {v}\n"); Ok(()) } },
+        {u64, "u64", |_, v| { pr_info!("u64 passed-in: {v}\n"); Ok(()) } },
+        {string, "string", |_, v| { pr_info!("string passed-in: {v}\n"); Ok(()) } },
+        {enum, "enum", [("first", 10), ("second", 20)], |_, v| {
+            pr_info!("enum passed-in: {v}\n"); Ok(()) }
+        },
+    }
+
+    fn try_new() -> Result {
+        pr_info!("context created!\n");
+        Ok(())
+    }
+}
+
+impl fs::Type for RustFs {
+    type Context = Self;
+    const SUPER_TYPE: fs::Super = fs::Super::Independent;
+    const NAME: &'static CStr = c_str!("rustfs");
+    const FLAGS: i32 = fs::flags::USERNS_MOUNT;
+
+    fn fill_super(_data: (), sb: fs::NewSuperBlock<'_, Self>) -> Result<&fs::SuperBlock<Self>> {
+        let sb = sb.init(
+            (),
+            &fs::SuperParams {
+                magic: 0x72757374,
+                ..fs::SuperParams::DEFAULT
+            },
+        )?;
+        let sb = sb.init_root()?;
+        Ok(sb)
+    }
+}
diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs
new file mode 100644
index 000000000000..6e1a926c6f62
--- /dev/null
+++ b/samples/rust/rust_minimal.rs
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust minimal sample.
+
+use kernel::prelude::*;
+
+module! {
+    type: RustMinimal,
+    name: b"rust_minimal",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust minimal sample",
+    license: b"GPL",
+}
+
+struct RustMinimal {
+    message: String,
+}
+
+impl kernel::Module for RustMinimal {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust minimal sample (init)\n");
+        pr_info!("Am I built-in? {}\n", !cfg!(MODULE));
+
+        Ok(RustMinimal {
+            message: "on the heap!".try_to_owned()?,
+        })
+    }
+}
+
+impl Drop for RustMinimal {
+    fn drop(&mut self) {
+        pr_info!("My message is {}\n", self.message);
+        pr_info!("Rust minimal sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_miscdev.rs b/samples/rust/rust_miscdev.rs
new file mode 100644
index 000000000000..647b77864f10
--- /dev/null
+++ b/samples/rust/rust_miscdev.rs
@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust miscellaneous device sample.
+
+use kernel::prelude::*;
+use kernel::{
+    file::{self, File},
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    miscdev,
+    sync::{CondVar, Mutex, Ref, RefBorrow, UniqueRef},
+};
+
+module! {
+    type: RustMiscdev,
+    name: b"rust_miscdev",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust miscellaneous device sample",
+    license: b"GPL",
+}
+
+const MAX_TOKENS: usize = 3;
+
+struct SharedStateInner {
+    token_count: usize,
+}
+
+struct SharedState {
+    state_changed: CondVar,
+    inner: Mutex<SharedStateInner>,
+}
+
+impl SharedState {
+    fn try_new() -> Result<Ref<Self>> {
+        let mut state = Pin::from(UniqueRef::try_new(Self {
+            // SAFETY: `condvar_init!` is called below.
+            state_changed: unsafe { CondVar::new() },
+            // SAFETY: `mutex_init!` is called below.
+            inner: unsafe { Mutex::new(SharedStateInner { token_count: 0 }) },
+        })?);
+
+        // SAFETY: `state_changed` is pinned when `state` is.
+        let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.state_changed) };
+        kernel::condvar_init!(pinned, "SharedState::state_changed");
+
+        // SAFETY: `inner` is pinned when `state` is.
+        let pinned = unsafe { state.as_mut().map_unchecked_mut(|s| &mut s.inner) };
+        kernel::mutex_init!(pinned, "SharedState::inner");
+
+        Ok(state.into())
+    }
+}
+
+struct Token;
+#[vtable]
+impl file::Operations for Token {
+    type Data = Ref<SharedState>;
+    type OpenData = Ref<SharedState>;
+
+    fn open(shared: &Ref<SharedState>, _file: &File) -> Result<Self::Data> {
+        Ok(shared.clone())
+    }
+
+    fn read(
+        shared: RefBorrow<'_, SharedState>,
+        _: &File,
+        data: &mut impl IoBufferWriter,
+        offset: u64,
+    ) -> Result<usize> {
+        // Succeed if the caller doesn't provide a buffer or if not at the start.
+        if data.is_empty() || offset != 0 {
+            return Ok(0);
+        }
+
+        {
+            let mut inner = shared.inner.lock();
+
+            // Wait until we are allowed to decrement the token count or a signal arrives.
+            while inner.token_count == 0 {
+                if shared.state_changed.wait(&mut inner) {
+                    return Err(EINTR);
+                }
+            }
+
+            // Consume a token.
+            inner.token_count -= 1;
+        }
+
+        // Notify a possible writer waiting.
+        shared.state_changed.notify_all();
+
+        // Write a one-byte 1 to the reader.
+        data.write_slice(&[1u8; 1])?;
+        Ok(1)
+    }
+
+    fn write(
+        shared: RefBorrow<'_, SharedState>,
+        _: &File,
+        data: &mut impl IoBufferReader,
+        _offset: u64,
+    ) -> Result<usize> {
+        {
+            let mut inner = shared.inner.lock();
+
+            // Wait until we are allowed to increment the token count or a signal arrives.
+            while inner.token_count == MAX_TOKENS {
+                if shared.state_changed.wait(&mut inner) {
+                    return Err(EINTR);
+                }
+            }
+
+            // Increment the number of token so that a reader can be released.
+            inner.token_count += 1;
+        }
+
+        // Notify a possible reader waiting.
+        shared.state_changed.notify_all();
+        Ok(data.len())
+    }
+}
+
+struct RustMiscdev {
+    _dev: Pin<Box<miscdev::Registration<Token>>>,
+}
+
+impl kernel::Module for RustMiscdev {
+    fn init(name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust miscellaneous device sample (init)\n");
+
+        let state = SharedState::try_new()?;
+
+        Ok(RustMiscdev {
+            _dev: miscdev::Registration::new_pinned(fmt!("{name}"), state)?,
+        })
+    }
+}
+
+impl Drop for RustMiscdev {
+    fn drop(&mut self) {
+        pr_info!("Rust miscellaneous device sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_module_parameters.rs b/samples/rust/rust_module_parameters.rs
new file mode 100644
index 000000000000..12fe5e738e83
--- /dev/null
+++ b/samples/rust/rust_module_parameters.rs
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust module parameters sample.
+
+use kernel::prelude::*;
+
+module! {
+    type: RustModuleParameters,
+    name: b"rust_module_parameters",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust module parameters sample",
+    license: b"GPL",
+    params: {
+        my_bool: bool {
+            default: true,
+            permissions: 0,
+            description: b"Example of bool",
+        },
+        my_i32: i32 {
+            default: 42,
+            permissions: 0o644,
+            description: b"Example of i32",
+        },
+        my_str: str {
+            default: b"default str val",
+            permissions: 0o644,
+            description: b"Example of a string param",
+        },
+        my_usize: usize {
+            default: 42,
+            permissions: 0o644,
+            description: b"Example of usize",
+        },
+        my_array: ArrayParam<i32, 3> {
+            default: [0, 1],
+            permissions: 0,
+            description: b"Example of array",
+        },
+    },
+}
+
+struct RustModuleParameters;
+
+impl kernel::Module for RustModuleParameters {
+    fn init(_name: &'static CStr, module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust module parameters sample (init)\n");
+
+        {
+            let lock = module.kernel_param_lock();
+            pr_info!("Parameters:\n");
+            pr_info!("  my_bool:    {}\n", my_bool.read());
+            pr_info!("  my_i32:     {}\n", my_i32.read(&lock));
+            pr_info!(
+                "  my_str:     {}\n",
+                core::str::from_utf8(my_str.read(&lock))?
+            );
+            pr_info!("  my_usize:   {}\n", my_usize.read(&lock));
+            pr_info!("  my_array:   {:?}\n", my_array.read());
+        }
+
+        Ok(RustModuleParameters)
+    }
+}
+
+impl Drop for RustModuleParameters {
+    fn drop(&mut self) {
+        pr_info!("Rust module parameters sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_netfilter.rs b/samples/rust/rust_netfilter.rs
new file mode 100644
index 000000000000..4bd5c07fee8c
--- /dev/null
+++ b/samples/rust/rust_netfilter.rs
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust netfilter sample.
+
+use kernel::net;
+use kernel::net::filter::{self as netfilter, inet, Disposition, Family};
+use kernel::prelude::*;
+
+module! {
+    type: RustNetfilter,
+    name: b"rust_netfilter",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust netfilter sample",
+    license: b"GPL",
+}
+
+struct RustNetfilter {
+    _in: Pin<Box<netfilter::Registration<Self>>>,
+    _out: Pin<Box<netfilter::Registration<Self>>>,
+}
+
+impl netfilter::Filter for RustNetfilter {
+    fn filter(_: (), skb: &net::SkBuff) -> Disposition {
+        let data = skb.head_data();
+        pr_info!(
+            "packet headlen={}, len={}, first bytes={:02x?}\n",
+            data.len(),
+            skb.len(),
+            &data[..core::cmp::min(10, data.len())]
+        );
+        Disposition::Accept
+    }
+}
+
+impl kernel::Module for RustNetfilter {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        Ok(Self {
+            _in: netfilter::Registration::new_pinned(
+                Family::INet(inet::Hook::PreRouting),
+                0,
+                net::init_ns().into(),
+                None,
+                (),
+            )?,
+            _out: netfilter::Registration::new_pinned(
+                Family::INet(inet::Hook::PostRouting),
+                0,
+                net::init_ns().into(),
+                None,
+                (),
+            )?,
+        })
+    }
+}
diff --git a/samples/rust/rust_platform.rs b/samples/rust/rust_platform.rs
new file mode 100644
index 000000000000..f62784676919
--- /dev/null
+++ b/samples/rust/rust_platform.rs
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust platform device driver sample.
+
+use kernel::{module_platform_driver, of, platform, prelude::*};
+
+module_platform_driver! {
+    type: Driver,
+    name: b"rust_platform",
+    license: b"GPL",
+}
+
+struct Driver;
+impl platform::Driver for Driver {
+    kernel::define_of_id_table! {(), [
+        (of::DeviceId::Compatible(b"rust,sample"), None),
+    ]}
+
+    fn probe(_dev: &mut platform::Device, _id_info: Option<&Self::IdInfo>) -> Result {
+        Ok(())
+    }
+}
diff --git a/samples/rust/rust_print.rs b/samples/rust/rust_print.rs
new file mode 100644
index 000000000000..30d96e025d89
--- /dev/null
+++ b/samples/rust/rust_print.rs
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust printing macros sample.
+
+use kernel::prelude::*;
+use kernel::{pr_cont, str::CStr, ThisModule};
+
+module! {
+    type: RustPrint,
+    name: b"rust_print",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust printing macros sample",
+    license: b"GPL",
+}
+
+struct RustPrint;
+
+impl kernel::Module for RustPrint {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust printing macros sample (init)\n");
+
+        pr_emerg!("Emergency message (level 0) without args\n");
+        pr_alert!("Alert message (level 1) without args\n");
+        pr_crit!("Critical message (level 2) without args\n");
+        pr_err!("Error message (level 3) without args\n");
+        pr_warn!("Warning message (level 4) without args\n");
+        pr_notice!("Notice message (level 5) without args\n");
+        pr_info!("Info message (level 6) without args\n");
+
+        pr_info!("A line that");
+        pr_cont!(" is continued");
+        pr_cont!(" without args\n");
+
+        pr_emerg!("{} message (level {}) with args\n", "Emergency", 0);
+        pr_alert!("{} message (level {}) with args\n", "Alert", 1);
+        pr_crit!("{} message (level {}) with args\n", "Critical", 2);
+        pr_err!("{} message (level {}) with args\n", "Error", 3);
+        pr_warn!("{} message (level {}) with args\n", "Warning", 4);
+        pr_notice!("{} message (level {}) with args\n", "Notice", 5);
+        pr_info!("{} message (level {}) with args\n", "Info", 6);
+
+        pr_info!("A {} that", "line");
+        pr_cont!(" is {}", "continued");
+        pr_cont!(" with {}\n", "args");
+
+        Ok(RustPrint)
+    }
+}
+
+impl Drop for RustPrint {
+    fn drop(&mut self) {
+        pr_info!("Rust printing macros sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_random.rs b/samples/rust/rust_random.rs
new file mode 100644
index 000000000000..771c7a940b3d
--- /dev/null
+++ b/samples/rust/rust_random.rs
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust random device.
+//!
+//! Adapted from Alex Gaynor's original available at
+//! <https://github.com/alex/just-use/blob/master/src/lib.rs>.
+
+use kernel::{
+    file::{self, File},
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    prelude::*,
+};
+
+module_misc_device! {
+    type: RandomFile,
+    name: b"rust_random",
+    author: b"Rust for Linux Contributors",
+    description: b"Just use /dev/urandom: Now with early-boot safety",
+    license: b"GPL",
+}
+
+struct RandomFile;
+
+#[vtable]
+impl file::Operations for RandomFile {
+    fn open(_data: &(), _file: &File) -> Result {
+        Ok(())
+    }
+
+    fn read(_this: (), file: &File, buf: &mut impl IoBufferWriter, _: u64) -> Result<usize> {
+        let total_len = buf.len();
+        let mut chunkbuf = [0; 256];
+
+        while !buf.is_empty() {
+            let len = chunkbuf.len().min(buf.len());
+            let chunk = &mut chunkbuf[0..len];
+            let blocking = (file.flags() & file::flags::O_NONBLOCK) == 0;
+
+            if blocking {
+                kernel::random::getrandom(chunk)?;
+            } else {
+                kernel::random::getrandom_nonblock(chunk)?;
+            }
+            buf.write_slice(chunk)?;
+        }
+        Ok(total_len)
+    }
+
+    fn write(_this: (), _file: &File, buf: &mut impl IoBufferReader, _: u64) -> Result<usize> {
+        let total_len = buf.len();
+        let mut chunkbuf = [0; 256];
+        while !buf.is_empty() {
+            let len = chunkbuf.len().min(buf.len());
+            let chunk = &mut chunkbuf[0..len];
+            buf.read_slice(chunk)?;
+            kernel::random::add_randomness(chunk);
+        }
+        Ok(total_len)
+    }
+}
diff --git a/samples/rust/rust_selftests.rs b/samples/rust/rust_selftests.rs
new file mode 100644
index 000000000000..965c48fd0e29
--- /dev/null
+++ b/samples/rust/rust_selftests.rs
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Self test cases for Rust.
+
+use kernel::prelude::*;
+// Keep the `use` for a test in its test function. Module-level `use`s are only for the test
+// framework.
+
+module! {
+    type: RustSelftests,
+    name: b"rust_selftests",
+    author: b"Rust for Linux Contributors",
+    description: b"Self test cases for Rust",
+    license: b"GPL",
+}
+
+struct RustSelftests;
+
+/// A summary of testing.
+///
+/// A test can
+///
+/// * pass (successfully), or
+/// * fail (without hitting any error), or
+/// * hit an error (interrupted).
+///
+/// This is the type that differentiates the first two (pass and fail) cases.
+///
+/// When a test hits an error, the test function should skip and return the error. Note that this
+/// doesn't mean the test fails, for example if the system doesn't have enough memory for
+/// testing, the test function may return an `Err(ENOMEM)` and skip.
+#[allow(dead_code)]
+enum TestSummary {
+    Pass,
+    Fail,
+}
+
+use TestSummary::Fail;
+use TestSummary::Pass;
+
+macro_rules! do_tests {
+    ($($name:ident),*) => {
+        let mut total = 0;
+        let mut pass = 0;
+        let mut fail = 0;
+
+        $({
+            total += 1;
+
+            match $name() {
+                Ok(Pass) => {
+                    pass += 1;
+                    pr_info!("{} passed!", stringify!($name));
+                },
+                Ok(Fail) => {
+                    fail += 1;
+                    pr_info!("{} failed!", stringify!($name));
+                },
+                Err(err) => {
+                    pr_info!("{} hit error {:?}", stringify!($name), err);
+                }
+            }
+        })*
+
+        pr_info!("{} tests run, {} passed, {} failed, {} hit errors\n",
+                 total, pass, fail, total - pass - fail);
+
+        if total == pass {
+            pr_info!("All tests passed. Congratulations!\n");
+        }
+    }
+}
+
+/// An example of test.
+#[allow(dead_code)]
+fn test_example() -> Result<TestSummary> {
+    // `use` declarations for the test can be put here, e.g. `use foo::bar;`.
+
+    // Always pass.
+    Ok(Pass)
+}
+
+impl kernel::Module for RustSelftests {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust self tests (init)\n");
+
+        do_tests! {
+            test_example // TODO: Remove when there is at least a real test.
+        };
+
+        Ok(RustSelftests)
+    }
+}
+
+impl Drop for RustSelftests {
+    fn drop(&mut self) {
+        pr_info!("Rust self tests (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_semaphore.rs b/samples/rust/rust_semaphore.rs
new file mode 100644
index 000000000000..e91f82a6abfb
--- /dev/null
+++ b/samples/rust/rust_semaphore.rs
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust semaphore sample.
+//!
+//! A counting semaphore that can be used by userspace.
+//!
+//! The count is incremented by writes to the device. A write of `n` bytes results in an increment
+//! of `n`. It is decremented by reads; each read results in the count being decremented by 1. If
+//! the count is already zero, a read will block until another write increments it.
+//!
+//! This can be used in user space from the shell for example  as follows (assuming a node called
+//! `semaphore`): `cat semaphore` decrements the count by 1 (waiting for it to become non-zero
+//! before decrementing); `echo -n 123 > semaphore` increments the semaphore by 3, potentially
+//! unblocking up to 3 blocked readers.
+
+use core::sync::atomic::{AtomicU64, Ordering};
+use kernel::{
+    condvar_init,
+    file::{self, File, IoctlCommand, IoctlHandler},
+    io_buffer::{IoBufferReader, IoBufferWriter},
+    miscdev::Registration,
+    mutex_init,
+    prelude::*,
+    sync::{CondVar, Mutex, Ref, UniqueRef},
+    user_ptr::{UserSlicePtrReader, UserSlicePtrWriter},
+};
+
+module! {
+    type: RustSemaphore,
+    name: b"rust_semaphore",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust semaphore sample",
+    license: b"GPL",
+}
+
+struct SemaphoreInner {
+    count: usize,
+    max_seen: usize,
+}
+
+struct Semaphore {
+    changed: CondVar,
+    inner: Mutex<SemaphoreInner>,
+}
+
+struct FileState {
+    read_count: AtomicU64,
+    shared: Ref<Semaphore>,
+}
+
+impl FileState {
+    fn consume(&self) -> Result {
+        let mut inner = self.shared.inner.lock();
+        while inner.count == 0 {
+            if self.shared.changed.wait(&mut inner) {
+                return Err(EINTR);
+            }
+        }
+        inner.count -= 1;
+        Ok(())
+    }
+}
+
+#[vtable]
+impl file::Operations for FileState {
+    type Data = Box<Self>;
+    type OpenData = Ref<Semaphore>;
+
+    fn open(shared: &Ref<Semaphore>, _file: &File) -> Result<Box<Self>> {
+        Ok(Box::try_new(Self {
+            read_count: AtomicU64::new(0),
+            shared: shared.clone(),
+        })?)
+    }
+
+    fn read(this: &Self, _: &File, data: &mut impl IoBufferWriter, offset: u64) -> Result<usize> {
+        if data.is_empty() || offset > 0 {
+            return Ok(0);
+        }
+        this.consume()?;
+        data.write_slice(&[0u8; 1])?;
+        this.read_count.fetch_add(1, Ordering::Relaxed);
+        Ok(1)
+    }
+
+    fn write(this: &Self, _: &File, data: &mut impl IoBufferReader, _offs: u64) -> Result<usize> {
+        {
+            let mut inner = this.shared.inner.lock();
+            inner.count = inner.count.saturating_add(data.len());
+            if inner.count > inner.max_seen {
+                inner.max_seen = inner.count;
+            }
+        }
+
+        this.shared.changed.notify_all();
+        Ok(data.len())
+    }
+
+    fn ioctl(this: &Self, file: &File, cmd: &mut IoctlCommand) -> Result<i32> {
+        cmd.dispatch::<Self>(this, file)
+    }
+}
+
+struct RustSemaphore {
+    _dev: Pin<Box<Registration<FileState>>>,
+}
+
+impl kernel::Module for RustSemaphore {
+    fn init(name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust semaphore sample (init)\n");
+
+        let mut sema = Pin::from(UniqueRef::try_new(Semaphore {
+            // SAFETY: `condvar_init!` is called below.
+            changed: unsafe { CondVar::new() },
+
+            // SAFETY: `mutex_init!` is called below.
+            inner: unsafe {
+                Mutex::new(SemaphoreInner {
+                    count: 0,
+                    max_seen: 0,
+                })
+            },
+        })?);
+
+        // SAFETY: `changed` is pinned when `sema` is.
+        let pinned = unsafe { sema.as_mut().map_unchecked_mut(|s| &mut s.changed) };
+        condvar_init!(pinned, "Semaphore::changed");
+
+        // SAFETY: `inner` is pinned when `sema` is.
+        let pinned = unsafe { sema.as_mut().map_unchecked_mut(|s| &mut s.inner) };
+        mutex_init!(pinned, "Semaphore::inner");
+
+        Ok(Self {
+            _dev: Registration::new_pinned(fmt!("{name}"), sema.into())?,
+        })
+    }
+}
+
+impl Drop for RustSemaphore {
+    fn drop(&mut self) {
+        pr_info!("Rust semaphore sample (exit)\n");
+    }
+}
+
+const IOCTL_GET_READ_COUNT: u32 = 0x80086301;
+const IOCTL_SET_READ_COUNT: u32 = 0x40086301;
+
+impl IoctlHandler for FileState {
+    type Target<'a> = &'a Self;
+
+    fn read(this: &Self, _: &File, cmd: u32, writer: &mut UserSlicePtrWriter) -> Result<i32> {
+        match cmd {
+            IOCTL_GET_READ_COUNT => {
+                writer.write(&this.read_count.load(Ordering::Relaxed))?;
+                Ok(0)
+            }
+            _ => Err(EINVAL),
+        }
+    }
+
+    fn write(this: &Self, _: &File, cmd: u32, reader: &mut UserSlicePtrReader) -> Result<i32> {
+        match cmd {
+            IOCTL_SET_READ_COUNT => {
+                this.read_count.store(reader.read()?, Ordering::Relaxed);
+                Ok(0)
+            }
+            _ => Err(EINVAL),
+        }
+    }
+}
diff --git a/samples/rust/rust_semaphore_c.c b/samples/rust/rust_semaphore_c.c
new file mode 100644
index 000000000000..7672b0b4c105
--- /dev/null
+++ b/samples/rust/rust_semaphore_c.c
@@ -0,0 +1,212 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Rust semaphore sample (in C, for comparison)
+ *
+ * This is a C implementation of `rust_semaphore.rs`. Refer to the description
+ * in that file for details on the device.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/refcount.h>
+#include <linux/wait.h>
+
+#define IOCTL_GET_READ_COUNT _IOR('c', 1, u64)
+#define IOCTL_SET_READ_COUNT _IOW('c', 1, u64)
+
+struct semaphore_state {
+	struct kref ref;
+	struct miscdevice miscdev;
+	wait_queue_head_t changed;
+	struct mutex mutex;
+	size_t count;
+	size_t max_seen;
+};
+
+struct file_state {
+	atomic64_t read_count;
+	struct semaphore_state *shared;
+};
+
+static int semaphore_consume(struct semaphore_state *state)
+{
+	DEFINE_WAIT(wait);
+
+	mutex_lock(&state->mutex);
+	while (state->count == 0) {
+		prepare_to_wait(&state->changed, &wait, TASK_INTERRUPTIBLE);
+		mutex_unlock(&state->mutex);
+		schedule();
+		finish_wait(&state->changed, &wait);
+		if (signal_pending(current))
+			return -EINTR;
+		mutex_lock(&state->mutex);
+	}
+
+	state->count--;
+	mutex_unlock(&state->mutex);
+
+	return 0;
+}
+
+static int semaphore_open(struct inode *nodp, struct file *filp)
+{
+	struct semaphore_state *shared =
+		container_of(filp->private_data, struct semaphore_state, miscdev);
+	struct file_state *state;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	kref_get(&shared->ref);
+	state->shared = shared;
+	atomic64_set(&state->read_count, 0);
+
+	filp->private_data = state;
+
+	return 0;
+}
+
+static ssize_t semaphore_write(struct file *filp, const char __user *buffer, size_t count,
+			       loff_t *ppos)
+{
+	struct file_state *state = filp->private_data;
+	struct semaphore_state *shared = state->shared;
+
+	mutex_lock(&shared->mutex);
+
+	shared->count += count;
+	if (shared->count < count)
+		shared->count = SIZE_MAX;
+
+	if (shared->count > shared->max_seen)
+		shared->max_seen = shared->count;
+
+	mutex_unlock(&shared->mutex);
+
+	wake_up_all(&shared->changed);
+
+	return count;
+}
+
+static ssize_t semaphore_read(struct file *filp, char __user *buffer,
+			      size_t count, loff_t *ppos)
+{
+	struct file_state *state = filp->private_data;
+	char c = 0;
+	int ret;
+
+	if (count == 0 || *ppos > 0)
+		return 0;
+
+	ret = semaphore_consume(state->shared);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(buffer, &c, sizeof(c)))
+		return -EFAULT;
+
+	atomic64_add(1, &state->read_count);
+	*ppos += 1;
+	return 1;
+}
+
+static long semaphore_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+	struct file_state *state = filp->private_data;
+	void __user *buffer = (void __user *)arg;
+	u64 value;
+
+	switch (cmd) {
+	case IOCTL_GET_READ_COUNT:
+		value = atomic64_read(&state->read_count);
+		if (copy_to_user(buffer, &value, sizeof(value)))
+			return -EFAULT;
+		return 0;
+	case IOCTL_SET_READ_COUNT:
+		if (copy_from_user(&value, buffer, sizeof(value)))
+			return -EFAULT;
+		atomic64_set(&state->read_count, value);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static void semaphore_free(struct kref *kref)
+{
+	struct semaphore_state *device;
+
+	device = container_of(kref, struct semaphore_state, ref);
+	kfree(device);
+}
+
+static int semaphore_release(struct inode *nodp, struct file *filp)
+{
+	struct file_state *state = filp->private_data;
+
+	kref_put(&state->shared->ref, semaphore_free);
+	kfree(state);
+	return 0;
+}
+
+static const struct file_operations semaphore_fops = {
+	.owner = THIS_MODULE,
+	.open = semaphore_open,
+	.read = semaphore_read,
+	.write = semaphore_write,
+	.compat_ioctl = semaphore_ioctl,
+	.release = semaphore_release,
+};
+
+static struct semaphore_state *device;
+
+static int __init semaphore_init(void)
+{
+	int ret;
+	struct semaphore_state *state;
+
+	pr_info("Rust semaphore sample (in C, for comparison) (init)\n");
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	mutex_init(&state->mutex);
+	kref_init(&state->ref);
+	init_waitqueue_head(&state->changed);
+
+	state->miscdev.fops = &semaphore_fops;
+	state->miscdev.minor = MISC_DYNAMIC_MINOR;
+	state->miscdev.name = "semaphore";
+
+	ret = misc_register(&state->miscdev);
+	if (ret < 0) {
+		kfree(state);
+		return ret;
+	}
+
+	device = state;
+
+	return 0;
+}
+
+static void __exit semaphore_exit(void)
+{
+	pr_info("Rust semaphore sample (in C, for comparison) (exit)\n");
+
+	misc_deregister(&device->miscdev);
+	kref_put(&device->ref, semaphore_free);
+}
+
+module_init(semaphore_init);
+module_exit(semaphore_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Rust for Linux Contributors");
+MODULE_DESCRIPTION("Rust semaphore sample (in C, for comparison)");
diff --git a/samples/rust/rust_stack_probing.rs b/samples/rust/rust_stack_probing.rs
new file mode 100644
index 000000000000..1448fe8e1b56
--- /dev/null
+++ b/samples/rust/rust_stack_probing.rs
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust stack probing sample.
+
+use kernel::prelude::*;
+
+module! {
+    type: RustStackProbing,
+    name: b"rust_stack_probing",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust stack probing sample",
+    license: b"GPL",
+}
+
+struct RustStackProbing;
+
+impl kernel::Module for RustStackProbing {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust stack probing sample (init)\n");
+
+        // Including this large variable on the stack will trigger
+        // stack probing on the supported archs.
+        // This will verify that stack probing does not lead to
+        // any errors if we need to link `__rust_probestack`.
+        let x: [u64; 514] = core::hint::black_box([5; 514]);
+        pr_info!("Large array has length: {}\n", x.len());
+
+        Ok(RustStackProbing)
+    }
+}
+
+impl Drop for RustStackProbing {
+    fn drop(&mut self) {
+        pr_info!("Rust stack probing sample (exit)\n");
+    }
+}
diff --git a/samples/rust/rust_sync.rs b/samples/rust/rust_sync.rs
new file mode 100644
index 000000000000..46637ace2f7f
--- /dev/null
+++ b/samples/rust/rust_sync.rs
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! Rust synchronisation primitives sample.
+
+use kernel::prelude::*;
+use kernel::{
+    condvar_init, mutex_init, spinlock_init,
+    sync::{CondVar, Mutex, SpinLock},
+};
+
+module! {
+    type: RustSync,
+    name: b"rust_sync",
+    author: b"Rust for Linux Contributors",
+    description: b"Rust synchronisation primitives sample",
+    license: b"GPL",
+}
+
+kernel::init_static_sync! {
+    static SAMPLE_MUTEX: Mutex<u32> = 10;
+    static SAMPLE_CONDVAR: CondVar;
+}
+
+struct RustSync;
+
+impl kernel::Module for RustSync {
+    fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result<Self> {
+        pr_info!("Rust synchronisation primitives sample (init)\n");
+
+        // Test mutexes.
+        {
+            // SAFETY: `init` is called below.
+            let mut data = Pin::from(Box::try_new(unsafe { Mutex::new(0) })?);
+            mutex_init!(data.as_mut(), "RustSync::init::data1");
+            *data.lock() = 10;
+            pr_info!("Value: {}\n", *data.lock());
+
+            // SAFETY: `init` is called below.
+            let mut cv = Pin::from(Box::try_new(unsafe { CondVar::new() })?);
+            condvar_init!(cv.as_mut(), "RustSync::init::cv1");
+
+            {
+                let mut guard = data.lock();
+                while *guard != 10 {
+                    let _ = cv.wait(&mut guard);
+                }
+            }
+            cv.notify_one();
+            cv.notify_all();
+            cv.free_waiters();
+        }
+
+        // Test static mutex + condvar.
+        *SAMPLE_MUTEX.lock() = 20;
+
+        {
+            let mut guard = SAMPLE_MUTEX.lock();
+            while *guard != 20 {
+                let _ = SAMPLE_CONDVAR.wait(&mut guard);
+            }
+        }
+
+        // Test spinlocks.
+        {
+            // SAFETY: `init` is called below.
+            let mut data = Pin::from(Box::try_new(unsafe { SpinLock::new(0) })?);
+            spinlock_init!(data.as_mut(), "RustSync::init::data2");
+            *data.lock() = 10;
+            pr_info!("Value: {}\n", *data.lock());
+
+            // SAFETY: `init` is called below.
+            let mut cv = Pin::from(Box::try_new(unsafe { CondVar::new() })?);
+            condvar_init!(cv.as_mut(), "RustSync::init::cv2");
+            {
+                let mut guard = data.lock();
+                while *guard != 10 {
+                    let _ = cv.wait(&mut guard);
+                }
+            }
+            cv.notify_one();
+            cv.notify_all();
+            cv.free_waiters();
+        }
+
+        Ok(RustSync)
+    }
+}
+
+impl Drop for RustSync {
+    fn drop(&mut self) {
+        pr_info!("Rust synchronisation primitives sample (exit)\n");
+    }
+}
diff --git a/scripts/.gitignore b/scripts/.gitignore
index eed308bef604..b7aec8eb1bd4 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 /asn1_compiler
 /bin2c
+/generate_rust_target
 /insert-sys-cert
 /kallsyms
 /module.lds
diff --git a/scripts/Kconfig.include b/scripts/Kconfig.include
index a0ccceb22cf8..274125307ebd 100644
--- a/scripts/Kconfig.include
+++ b/scripts/Kconfig.include
@@ -36,12 +36,12 @@ ld-option = $(success,$(LD) -v $(1))
 as-instr = $(success,printf "%b\n" "$(1)" | $(CC) $(CLANG_FLAGS) -c -x assembler -o /dev/null -)
 
 # check if $(CC) and $(LD) exist
-$(error-if,$(failure,command -v $(CC)),compiler '$(CC)' not found)
+$(error-if,$(failure,command -v $(CC)),C compiler '$(CC)' not found)
 $(error-if,$(failure,command -v $(LD)),linker '$(LD)' not found)
 
-# Get the compiler name, version, and error out if it is not supported.
+# Get the C compiler name, version, and error out if it is not supported.
 cc-info := $(shell,$(srctree)/scripts/cc-version.sh $(CC))
-$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this compiler is not supported.)
+$(error-if,$(success,test -z "$(cc-info)"),Sorry$(comma) this C compiler is not supported.)
 cc-name := $(shell,set -- $(cc-info) && echo $1)
 cc-version := $(shell,set -- $(cc-info) && echo $2)
 
diff --git a/scripts/Makefile b/scripts/Makefile
index f084f08ed176..1575af84d557 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -10,6 +10,9 @@ hostprogs-always-$(CONFIG_BUILDTIME_TABLE_SORT)		+= sorttable
 hostprogs-always-$(CONFIG_ASN1)				+= asn1_compiler
 hostprogs-always-$(CONFIG_MODULE_SIG_FORMAT)		+= sign-file
 hostprogs-always-$(CONFIG_SYSTEM_EXTRA_CERTIFICATE)	+= insert-sys-cert
+hostprogs-always-$(CONFIG_RUST)				+= generate_rust_target
+
+generate_rust_target-rust := y
 
 HOSTCFLAGS_sorttable.o = -I$(srctree)/tools/include
 HOSTLDLIBS_sorttable = -lpthread
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 784f46d41959..00a0cd8f6e9f 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -26,6 +26,7 @@ EXTRA_CPPFLAGS :=
 EXTRA_LDFLAGS  :=
 asflags-y  :=
 ccflags-y  :=
+rustflags-y :=
 cppflags-y :=
 ldflags-y  :=
 
@@ -271,6 +272,65 @@ quiet_cmd_cc_lst_c = MKLST   $@
 $(obj)/%.lst: $(src)/%.c FORCE
 	$(call if_changed_dep,cc_lst_c)
 
+# Compile Rust sources (.rs)
+# ---------------------------------------------------------------------------
+
+rust_allowed_features := allocator_api,bench_black_box,core_ffi_c,generic_associated_types,const_ptr_offset_from,const_refs_to_cell
+
+rust_common_cmd = \
+	RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \
+	-Zallow-features=$(rust_allowed_features) \
+	-Zcrate-attr=no_std \
+	-Zcrate-attr='feature($(rust_allowed_features))' \
+	--extern alloc --extern kernel \
+	--crate-type rlib --out-dir $(obj) -L $(objtree)/rust/ \
+	--crate-name $(basename $(notdir $@))
+
+rust_handle_depfile = \
+	mv $(obj)/$(basename $(notdir $@)).d $(depfile); \
+	sed -i '/^\#/d' $(depfile)
+
+# `--emit=obj`, `--emit=asm` and `--emit=llvm-ir` imply a single codegen unit
+# will be used. We explicitly request `-Ccodegen-units=1` in any case, and
+# the compiler shows a warning if it is not 1. However, if we ever stop
+# requesting it explicitly and we start using some other `--emit` that does not
+# imply it (and for which codegen is performed), then we would be out of sync,
+# i.e. the outputs we would get for the different single targets (e.g. `.ll`)
+# would not match each other.
+
+quiet_cmd_rustc_o_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_o_rs = \
+	$(rust_common_cmd) --emit=dep-info,obj $<; \
+	$(rust_handle_depfile)
+
+$(obj)/%.o: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_o_rs)
+
+quiet_cmd_rustc_rsi_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_rsi_rs = \
+	$(rust_common_cmd) --emit=dep-info -Zunpretty=expanded $< >$@; \
+	command -v $(RUSTFMT) >/dev/null && $(RUSTFMT) $@; \
+	$(rust_handle_depfile)
+
+$(obj)/%.rsi: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_rsi_rs)
+
+quiet_cmd_rustc_s_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_s_rs = \
+	$(rust_common_cmd) --emit=dep-info,asm $<; \
+	$(rust_handle_depfile)
+
+$(obj)/%.s: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_s_rs)
+
+quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@
+      cmd_rustc_ll_rs = \
+	$(rust_common_cmd) --emit=dep-info,llvm-ir $<; \
+	$(rust_handle_depfile)
+
+$(obj)/%.ll: $(src)/%.rs FORCE
+	$(call if_changed_dep,rustc_ll_rs)
+
 # Compile assembler sources (.S)
 # ---------------------------------------------------------------------------
 
diff --git a/scripts/Makefile.debug b/scripts/Makefile.debug
index 9f39b0130551..fe87389d52c0 100644
--- a/scripts/Makefile.debug
+++ b/scripts/Makefile.debug
@@ -1,4 +1,5 @@
 DEBUG_CFLAGS	:=
+DEBUG_RUSTFLAGS	:=
 
 ifdef CONFIG_DEBUG_INFO_SPLIT
 DEBUG_CFLAGS	+= -gsplit-dwarf
@@ -10,6 +11,12 @@ ifndef CONFIG_AS_IS_LLVM
 KBUILD_AFLAGS	+= -Wa,-gdwarf-2
 endif
 
+ifdef CONFIG_DEBUG_INFO_REDUCED
+DEBUG_RUSTFLAGS += -Cdebuginfo=1
+else
+DEBUG_RUSTFLAGS += -Cdebuginfo=2
+endif
+
 ifndef CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
 dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4
 dwarf-version-$(CONFIG_DEBUG_INFO_DWARF5) := 5
@@ -31,3 +38,6 @@ endif
 
 KBUILD_CFLAGS += $(DEBUG_CFLAGS)
 export DEBUG_CFLAGS
+
+KBUILD_RUSTFLAGS += $(DEBUG_RUSTFLAGS)
+export DEBUG_RUSTFLAGS
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index 278b4d6ac945..da133780b751 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -22,6 +22,8 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE
 # to preprocess a data file.
 #
 # Both C and C++ are supported, but preferred language is C for such utilities.
+# Rust is also supported, but it may only be used in scenarios where a Rust
+# toolchain is required to be available (e.g. when  `CONFIG_RUST` is enabled).
 #
 # Sample syntax (see Documentation/kbuild/makefiles.rst for reference)
 # hostprogs := bin2hex
@@ -37,15 +39,20 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE
 # qconf-objs      := menu.o
 # Will compile qconf as a C++ program, and menu as a C program.
 # They are linked as C++ code to the executable qconf
+#
+# hostprogs   := target
+# target-rust := y
+# Will compile `target` as a Rust program, using `target.rs` as the crate root.
+# The crate may consist of several source files.
 
 # C code
 # Executables compiled from a single .c file
 host-csingle	:= $(foreach m,$(hostprogs), \
-			$(if $($(m)-objs)$($(m)-cxxobjs),,$(m)))
+			$(if $($(m)-objs)$($(m)-cxxobjs)$($(m)-rust),,$(m)))
 
 # C executables linked based on several .o files
 host-cmulti	:= $(foreach m,$(hostprogs),\
-		   $(if $($(m)-cxxobjs),,$(if $($(m)-objs),$(m))))
+		   $(if $($(m)-cxxobjs)$($(m)-rust),,$(if $($(m)-objs),$(m))))
 
 # Object (.o) files compiled from .c files
 host-cobjs	:= $(sort $(foreach m,$(hostprogs),$($(m)-objs)))
@@ -58,11 +65,17 @@ host-cxxmulti	:= $(foreach m,$(hostprogs),$(if $($(m)-cxxobjs),$(m)))
 # C++ Object (.o) files compiled from .cc files
 host-cxxobjs	:= $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs)))
 
+# Rust code
+# Executables compiled from a single Rust crate (which may consist of
+# one or more .rs files)
+host-rust	:= $(foreach m,$(hostprogs),$(if $($(m)-rust),$(m)))
+
 host-csingle	:= $(addprefix $(obj)/,$(host-csingle))
 host-cmulti	:= $(addprefix $(obj)/,$(host-cmulti))
 host-cobjs	:= $(addprefix $(obj)/,$(host-cobjs))
 host-cxxmulti	:= $(addprefix $(obj)/,$(host-cxxmulti))
 host-cxxobjs	:= $(addprefix $(obj)/,$(host-cxxobjs))
+host-rust	:= $(addprefix $(obj)/,$(host-rust))
 
 #####
 # Handle options to gcc. Support building with separate output directory
@@ -71,6 +84,8 @@ _hostc_flags   = $(KBUILD_HOSTCFLAGS)   $(HOST_EXTRACFLAGS)   \
                  $(HOSTCFLAGS_$(target-stem).o)
 _hostcxx_flags = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
                  $(HOSTCXXFLAGS_$(target-stem).o)
+_hostrust_flags = $(KBUILD_HOSTRUSTFLAGS) $(HOST_EXTRARUSTFLAGS) \
+                  $(HOSTRUSTFLAGS_$(target-stem))
 
 # $(objtree)/$(obj) for including generated headers from checkin source files
 ifeq ($(KBUILD_EXTMOD),)
@@ -82,6 +97,7 @@ endif
 
 hostc_flags    = -Wp,-MMD,$(depfile) $(_hostc_flags)
 hostcxx_flags  = -Wp,-MMD,$(depfile) $(_hostcxx_flags)
+hostrust_flags = $(_hostrust_flags)
 
 #####
 # Compile programs on the host
@@ -128,5 +144,17 @@ quiet_cmd_host-cxxobjs	= HOSTCXX $@
 $(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE
 	$(call if_changed_dep,host-cxxobjs)
 
+# Create executable from a single Rust crate (which may consist of
+# one or more `.rs` files)
+# host-rust -> Executable
+quiet_cmd_host-rust	= HOSTRUSTC $@
+      cmd_host-rust	= \
+	$(HOSTRUSTC) $(hostrust_flags) --emit=dep-info,link \
+		--out-dir=$(obj)/ $<; \
+	mv $(obj)/$(target-stem).d $(depfile); \
+	sed -i '/^\#/d' $(depfile)
+$(host-rust): $(obj)/%: $(src)/%.rs FORCE
+	$(call if_changed_dep,host-rust)
+
 targets += $(host-csingle) $(host-cmulti) $(host-cobjs) \
-	   $(host-cxxmulti) $(host-cxxobjs)
+	   $(host-cxxmulti) $(host-cxxobjs) $(host-rust)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 3fb6a99e78c4..c88b98b5dc44 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -8,6 +8,7 @@ ldflags-y  += $(EXTRA_LDFLAGS)
 # flags that take effect in current and sub directories
 KBUILD_AFLAGS += $(subdir-asflags-y)
 KBUILD_CFLAGS += $(subdir-ccflags-y)
+KBUILD_RUSTFLAGS += $(subdir-rustflags-y)
 
 # Figure out what we need to build from the various variables
 # ===========================================================================
@@ -128,6 +129,10 @@ _c_flags       = $(filter-out $(CFLAGS_REMOVE_$(target-stem).o), \
                      $(filter-out $(ccflags-remove-y), \
                          $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(ccflags-y)) \
                      $(CFLAGS_$(target-stem).o))
+_rust_flags    = $(filter-out $(RUSTFLAGS_REMOVE_$(target-stem).o), \
+                     $(filter-out $(rustflags-remove-y), \
+                         $(KBUILD_RUSTFLAGS) $(rustflags-y)) \
+                     $(RUSTFLAGS_$(target-stem).o))
 _a_flags       = $(filter-out $(AFLAGS_REMOVE_$(target-stem).o), \
                      $(filter-out $(asflags-remove-y), \
                          $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(asflags-y)) \
@@ -202,6 +207,11 @@ modkern_cflags =                                          \
 		$(KBUILD_CFLAGS_MODULE) $(CFLAGS_MODULE), \
 		$(KBUILD_CFLAGS_KERNEL) $(CFLAGS_KERNEL) $(modfile_flags))
 
+modkern_rustflags =                                              \
+	$(if $(part-of-module),                                   \
+		$(KBUILD_RUSTFLAGS_MODULE) $(RUSTFLAGS_MODULE), \
+		$(KBUILD_RUSTFLAGS_KERNEL) $(RUSTFLAGS_KERNEL))
+
 modkern_aflags = $(if $(part-of-module),				\
 			$(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE),	\
 			$(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL))
@@ -211,6 +221,8 @@ c_flags        = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 		 $(_c_flags) $(modkern_cflags)                           \
 		 $(basename_flags) $(modname_flags)
 
+rust_flags     = $(_rust_flags) $(modkern_rustflags) @$(objtree)/include/generated/rustc_cfg
+
 a_flags        = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 		 $(_a_flags) $(modkern_aflags)
 
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 35100e981f4a..9a1fa6aa30fe 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -39,11 +39,13 @@ quiet_cmd_ld_ko_o = LD [M]  $@
 
 quiet_cmd_btf_ko = BTF [M] $@
       cmd_btf_ko = 							\
-	if [ -f vmlinux ]; then						\
+	if [ ! -f vmlinux ]; then					\
+		printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
+	elif [ -n "$(CONFIG_RUST)" ] && $(srctree)/scripts/is_rust_module.sh $@; then 		\
+		printf "Skipping BTF generation for %s because it's a Rust module\n" $@ 1>&2; \
+	else								\
 		LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_base vmlinux $@; \
 		$(RESOLVE_BTFIDS) -b vmlinux $@; 			\
-	else								\
-		printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
 	fi;
 
 # Same as newer-prereqs, but allows to exclude specified extra dependencies
diff --git a/scripts/cc-version.sh b/scripts/cc-version.sh
index f1952c522466..2401c86fcf53 100755
--- a/scripts/cc-version.sh
+++ b/scripts/cc-version.sh
@@ -1,13 +1,13 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 #
-# Print the compiler name and its version in a 5 or 6-digit form.
+# Print the C compiler name and its version in a 5 or 6-digit form.
 # Also, perform the minimum version check.
 
 set -e
 
-# Print the compiler name and some version components.
-get_compiler_info()
+# Print the C compiler name and some version components.
+get_c_compiler_info()
 {
 	cat <<- EOF | "$@" -E -P -x c - 2>/dev/null
 	#if defined(__clang__)
@@ -32,7 +32,7 @@ get_canonical_version()
 
 # $@ instead of $1 because multiple words might be given, e.g. CC="ccache gcc".
 orig_args="$@"
-set -- $(get_compiler_info "$@")
+set -- $(get_c_compiler_info "$@")
 
 name=$1
 
@@ -52,7 +52,7 @@ ICC)
 	min_version=$($min_tool_version icc)
 	;;
 *)
-	echo "$orig_args: unknown compiler" >&2
+	echo "$orig_args: unknown C compiler" >&2
 	exit 1
 	;;
 esac
@@ -62,7 +62,7 @@ min_cversion=$(get_canonical_version $min_version)
 
 if [ "$cversion" -lt "$min_cversion" ]; then
 	echo >&2 "***"
-	echo >&2 "*** Compiler is too old."
+	echo >&2 "*** C compiler is too old."
 	echo >&2 "***   Your $name version:    $version"
 	echo >&2 "***   Minimum $name version: $min_version"
 	echo >&2 "***"
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 503e8abbb2c1..bd0025d77bcf 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3615,7 +3615,7 @@ sub process {
 				my $comment = "";
 				if ($realfile =~ /\.(h|s|S)$/) {
 					$comment = '/*';
-				} elsif ($realfile =~ /\.(c|dts|dtsi)$/) {
+				} elsif ($realfile =~ /\.(c|rs|dts|dtsi)$/) {
 					$comment = '//';
 				} elsif (($checklicenseline == 2) || $realfile =~ /\.(sh|pl|py|awk|tc|yaml)$/) {
 					$comment = '#';
@@ -3663,7 +3663,7 @@ sub process {
 		}
 
 # check we are in a valid source file if not then ignore this hunk
-		next if ($realfile !~ /\.(h|c|s|S|sh|dtsi|dts)$/);
+		next if ($realfile !~ /\.(h|c|rs|s|S|sh|dtsi|dts)$/);
 
 # check for using SPDX-License-Identifier on the wrong line number
 		if ($realline != $checklicenseline &&
@@ -6782,15 +6782,19 @@ sub process {
 				}
 				if ($bad_specifier ne "") {
 					my $stat_real = get_stat_real($linenr, $lc);
+					my $msg_level = \&WARN;
 					my $ext_type = "Invalid";
 					my $use = "";
 					if ($bad_specifier =~ /p[Ff]/) {
 						$use = " - use %pS instead";
 						$use =~ s/pS/ps/ if ($bad_specifier =~ /pf/);
+					} elsif ($bad_specifier =~ /pA/) {
+						$use =  " - '%pA' is only intended to be used from Rust code";
+						$msg_level = \&ERROR;
 					}
 
-					WARN("VSPRINTF_POINTER_EXTENSION",
-					     "$ext_type vsprintf pointer extension '$bad_specifier'$use\n" . "$here\n$stat_real\n");
+					&{$msg_level}("VSPRINTF_POINTER_EXTENSION",
+						      "$ext_type vsprintf pointer extension '$bad_specifier'$use\n" . "$here\n$stat_real\n");
 				}
 			}
 		}
diff --git a/scripts/decode_stacktrace.sh b/scripts/decode_stacktrace.sh
index 7075e26ab2c4..564c5632e1a2 100755
--- a/scripts/decode_stacktrace.sh
+++ b/scripts/decode_stacktrace.sh
@@ -8,6 +8,14 @@ usage() {
 	echo "	$0 -r <release> | <vmlinux> [<base path>|auto] [<modules path>]"
 }
 
+# Try to find a Rust demangler
+if type llvm-cxxfilt >/dev/null 2>&1 ; then
+	cppfilt=llvm-cxxfilt
+elif type c++filt >/dev/null 2>&1 ; then
+	cppfilt=c++filt
+	cppfilt_opts=-i
+fi
+
 if [[ $1 == "-r" ]] ; then
 	vmlinux=""
 	basepath="auto"
@@ -180,6 +188,12 @@ parse_symbol() {
 	# In the case of inlines, move everything to same line
 	code=${code//$'\n'/' '}
 
+	# Demangle if the name looks like a Rust symbol and if
+	# we got a Rust demangler
+	if [[ $name =~ ^_R && $cppfilt != "" ]] ; then
+		name=$("$cppfilt" "$cppfilt_opts" "$name")
+	fi
+
 	# Replace old address with pretty line numbers
 	symbol="$segment$name ($code)"
 }
diff --git a/scripts/generate_rust_analyzer.py b/scripts/generate_rust_analyzer.py
new file mode 100755
index 000000000000..ecc7ea9a4dcf
--- /dev/null
+++ b/scripts/generate_rust_analyzer.py
@@ -0,0 +1,141 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+"""generate_rust_analyzer - Generates the `rust-project.json` file for `rust-analyzer`.
+"""
+
+import argparse
+import json
+import logging
+import pathlib
+import sys
+
+def generate_crates(srctree, objtree, sysroot_src):
+    # Generate the configuration list.
+    cfg = []
+    with open(objtree / "include" / "generated" / "rustc_cfg") as fd:
+        for line in fd:
+            line = line.replace("--cfg=", "")
+            line = line.replace("\n", "")
+            cfg.append(line)
+
+    # Now fill the crates list -- dependencies need to come first.
+    #
+    # Avoid O(n^2) iterations by keeping a map of indexes.
+    crates = []
+    crates_indexes = {}
+
+    def append_crate(display_name, root_module, deps, cfg=[], is_workspace_member=True, is_proc_macro=False):
+        crates_indexes[display_name] = len(crates)
+        crates.append({
+            "display_name": display_name,
+            "root_module": str(root_module),
+            "is_workspace_member": is_workspace_member,
+            "is_proc_macro": is_proc_macro,
+            "deps": [{"crate": crates_indexes[dep], "name": dep} for dep in deps],
+            "cfg": cfg,
+            "edition": "2021",
+            "env": {
+                "RUST_MODFILE": "This is only for rust-analyzer"
+            }
+        })
+
+    # First, the ones in `rust/` since they are a bit special.
+    append_crate(
+        "core",
+        sysroot_src / "core" / "src" / "lib.rs",
+        [],
+        is_workspace_member=False,
+    )
+
+    append_crate(
+        "compiler_builtins",
+        srctree / "rust" / "compiler_builtins.rs",
+        [],
+    )
+
+    append_crate(
+        "alloc",
+        srctree / "rust" / "alloc" / "lib.rs",
+        ["core", "compiler_builtins"],
+    )
+
+    append_crate(
+        "macros",
+        srctree / "rust" / "macros" / "lib.rs",
+        [],
+        is_proc_macro=True,
+    )
+    crates[-1]["proc_macro_dylib_path"] = "rust/libmacros.so"
+
+    append_crate(
+        "build_error",
+        srctree / "rust" / "build_error.rs",
+        ["core", "compiler_builtins"],
+    )
+
+    append_crate(
+        "bindings",
+        srctree / "rust"/ "bindings" / "lib.rs",
+        ["core"],
+        cfg=cfg,
+    )
+    crates[-1]["env"]["OBJTREE"] = str(objtree.resolve(True))
+
+    append_crate(
+        "kernel",
+        srctree / "rust" / "kernel" / "lib.rs",
+        ["core", "alloc", "macros", "build_error", "bindings"],
+        cfg=cfg,
+    )
+    crates[-1]["source"] = {
+        "include_dirs": [
+            str(srctree / "rust" / "kernel"),
+            str(objtree / "rust")
+        ],
+        "exclude_dirs": [],
+    }
+
+    # Then, the rest outside of `rust/`.
+    #
+    # We explicitly mention the top-level folders we want to cover.
+    for folder in ("samples", "drivers"):
+        for path in (srctree / folder).rglob("*.rs"):
+            logging.info("Checking %s", path)
+            name = path.name.replace(".rs", "")
+
+            # Skip those that are not crate roots.
+            if f"{name}.o" not in open(path.parent / "Makefile").read():
+                continue
+
+            logging.info("Adding %s", name)
+            append_crate(
+                name,
+                path,
+                ["core", "alloc", "kernel"],
+                cfg=cfg,
+            )
+
+    return crates
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--verbose', '-v', action='store_true')
+    parser.add_argument("srctree", type=pathlib.Path)
+    parser.add_argument("objtree", type=pathlib.Path)
+    parser.add_argument("sysroot_src", type=pathlib.Path)
+    args = parser.parse_args()
+
+    logging.basicConfig(
+        format="[%(asctime)s] [%(levelname)s] %(message)s",
+        level=logging.INFO if args.verbose else logging.WARNING
+    )
+
+    rust_project = {
+        "crates": generate_crates(args.srctree, args.objtree, args.sysroot_src),
+        "sysroot_src": str(args.sysroot_src),
+    }
+
+    json.dump(rust_project, sys.stdout, sort_keys=True, indent=4)
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts/generate_rust_target.rs b/scripts/generate_rust_target.rs
new file mode 100644
index 000000000000..0a1ba95d74e7
--- /dev/null
+++ b/scripts/generate_rust_target.rs
@@ -0,0 +1,232 @@
+// SPDX-License-Identifier: GPL-2.0
+
+//! The custom target specification file generator for `rustc`.
+//!
+//! To configure a target from scratch, a JSON-encoded file has to be passed
+//! to `rustc` (introduced in [RFC 131]). These options and the file itself are
+//! unstable. Eventually, `rustc` should provide a way to do this in a stable
+//! manner. For instance, via command-line arguments. Therefore, this file
+//! should avoid using keys which can be set via `-C` or `-Z` options.
+//!
+//! [RFC 131]: https://rust-lang.github.io/rfcs/0131-target-specification.html
+
+use std::{
+    collections::HashMap,
+    fmt::{Display, Formatter, Result},
+    io::BufRead,
+};
+
+enum Value {
+    Boolean(bool),
+    Number(i32),
+    String(String),
+    Object(Object),
+}
+
+type Object = Vec<(String, Value)>;
+
+/// Minimal "almost JSON" generator (e.g. no `null`s, no arrays, no escaping),
+/// enough for this purpose.
+impl Display for Value {
+    fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
+        match self {
+            Value::Boolean(boolean) => write!(formatter, "{}", boolean),
+            Value::Number(number) => write!(formatter, "{}", number),
+            Value::String(string) => write!(formatter, "\"{}\"", string),
+            Value::Object(object) => {
+                formatter.write_str("{")?;
+                if let [ref rest @ .., ref last] = object[..] {
+                    for (key, value) in rest {
+                        write!(formatter, "\"{}\": {},", key, value)?;
+                    }
+                    write!(formatter, "\"{}\": {}", last.0, last.1)?;
+                }
+                formatter.write_str("}")
+            }
+        }
+    }
+}
+
+struct TargetSpec(Object);
+
+impl TargetSpec {
+    fn new() -> TargetSpec {
+        TargetSpec(Vec::new())
+    }
+}
+
+trait Push<T> {
+    fn push(&mut self, key: &str, value: T);
+}
+
+impl Push<bool> for TargetSpec {
+    fn push(&mut self, key: &str, value: bool) {
+        self.0.push((key.to_string(), Value::Boolean(value)));
+    }
+}
+
+impl Push<i32> for TargetSpec {
+    fn push(&mut self, key: &str, value: i32) {
+        self.0.push((key.to_string(), Value::Number(value)));
+    }
+}
+
+impl Push<String> for TargetSpec {
+    fn push(&mut self, key: &str, value: String) {
+        self.0.push((key.to_string(), Value::String(value)));
+    }
+}
+
+impl Push<&str> for TargetSpec {
+    fn push(&mut self, key: &str, value: &str) {
+        self.push(key, value.to_string());
+    }
+}
+
+impl Push<Object> for TargetSpec {
+    fn push(&mut self, key: &str, value: Object) {
+        self.0.push((key.to_string(), Value::Object(value)));
+    }
+}
+
+impl Display for TargetSpec {
+    fn fmt(&self, formatter: &mut Formatter<'_>) -> Result {
+        // We add some newlines for clarity.
+        formatter.write_str("{\n")?;
+        if let [ref rest @ .., ref last] = self.0[..] {
+            for (key, value) in rest {
+                write!(formatter, "    \"{}\": {},\n", key, value)?;
+            }
+            write!(formatter, "    \"{}\": {}\n", last.0, last.1)?;
+        }
+        formatter.write_str("}")
+    }
+}
+
+struct KernelConfig(HashMap<String, String>);
+
+impl KernelConfig {
+    /// Parses `include/config/auto.conf` from `stdin`.
+    fn from_stdin() -> KernelConfig {
+        let mut result = HashMap::new();
+
+        let stdin = std::io::stdin();
+        let mut handle = stdin.lock();
+        let mut line = String::new();
+
+        loop {
+            line.clear();
+
+            if handle.read_line(&mut line).unwrap() == 0 {
+                break;
+            }
+
+            if line.starts_with('#') {
+                continue;
+            }
+
+            let (key, value) = line.split_once('=').expect("Missing `=` in line.");
+            result.insert(key.to_string(), value.trim_end_matches('\n').to_string());
+        }
+
+        KernelConfig(result)
+    }
+
+    /// Does the option exist in the configuration (any value)?
+    ///
+    /// The argument must be passed without the `CONFIG_` prefix.
+    /// This avoids repetition and it also avoids `fixdep` making us
+    /// depend on it.
+    fn has(&self, option: &str) -> bool {
+        let option = "CONFIG_".to_owned() + option;
+        self.0.contains_key(&option)
+    }
+}
+
+fn main() {
+    let cfg = KernelConfig::from_stdin();
+    let mut ts = TargetSpec::new();
+
+    // `llvm-target`s are taken from `scripts/Makefile.clang`.
+    if cfg.has("ARM") {
+        ts.push("arch", "arm");
+        ts.push(
+            "data-layout",
+            "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64",
+        );
+        ts.push("features", "+strict-align,+v6");
+        ts.push("llvm-target", "arm-linux-gnueabi");
+        ts.push("max-atomic-width", 64);
+        ts.push("target-mcount", "\\u0001__gnu_mcount_nc");
+        ts.push("target-pointer-width", "32");
+    } else if cfg.has("ARM64") {
+        ts.push("arch", "aarch64");
+        ts.push(
+            "data-layout",
+            "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128",
+        );
+        ts.push("disable-redzone", true);
+        ts.push("features", "+strict-align,-neon,-fp-armv8");
+        ts.push("llvm-target", "aarch64-linux-gnu");
+        ts.push("max-atomic-width", 128);
+        ts.push("target-pointer-width", "64");
+    } else if cfg.has("PPC") {
+        ts.push("arch", "powerpc64");
+        ts.push("code-model", "large");
+        ts.push("data-layout", "e-m:e-i64:64-n32:64");
+        ts.push("features", "-altivec,-vsx,-hard-float");
+        ts.push("llvm-target", "powerpc64le-linux-gnu");
+        ts.push("max-atomic-width", 64);
+        ts.push("target-mcount", "_mcount");
+        ts.push("target-pointer-width", "64");
+    } else if cfg.has("RISCV") {
+        if cfg.has("64BIT") {
+            ts.push("arch", "riscv64");
+            ts.push("data-layout", "e-m:e-p:64:64-i64:64-i128:128-n64-S128");
+            ts.push("llvm-target", "riscv64-linux-gnu");
+            ts.push("target-pointer-width", "64");
+        } else {
+            ts.push("arch", "riscv32");
+            ts.push("data-layout", "e-m:e-p:32:32-i64:64-n32-S128");
+            ts.push("llvm-target", "riscv32-linux-gnu");
+            ts.push("target-pointer-width", "32");
+        }
+        ts.push("code-model", "medium");
+        ts.push("disable-redzone", true);
+        let mut features = "+m,+a".to_string();
+        if cfg.has("RISCV_ISA_C") {
+            features += ",+c";
+        }
+        ts.push("features", features);
+    } else if cfg.has("X86_64") {
+        ts.push("arch", "x86_64");
+        ts.push(
+            "data-layout",
+            "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128",
+        );
+        let mut features = "-3dnow,-3dnowa,-mmx,+soft-float".to_string();
+        if cfg.has("RETPOLINE") {
+            features += ",+retpoline-external-thunk";
+        }
+        ts.push("features", features);
+        ts.push("llvm-target", "x86_64-linux-gnu");
+        ts.push("target-pointer-width", "64");
+    } else {
+        panic!("Unsupported architecture");
+    }
+
+    ts.push("emit-debug-gdb-scripts", false);
+    ts.push("frame-pointer", "may-omit");
+    ts.push(
+        "stack-probes",
+        vec![("kind".to_string(), Value::String("none".to_string()))],
+    );
+
+    // Everything else is LE, whether `CPU_LITTLE_ENDIAN` is declared or not
+    // (e.g. x86). It is also `rustc`'s default.
+    if cfg.has("CPU_BIG_ENDIAN") {
+        ts.push("target-endian", "big");
+    }
+
+    println!("{}", ts);
+}
diff --git a/scripts/is_rust_module.sh b/scripts/is_rust_module.sh
new file mode 100755
index 000000000000..28b3831a7593
--- /dev/null
+++ b/scripts/is_rust_module.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# is_rust_module.sh module.ko
+#
+# Returns `0` if `module.ko` is a Rust module, `1` otherwise.
+
+set -e
+
+# Using the `16_` prefix ensures other symbols with the same substring
+# are not picked up (even if it would be unlikely). The last part is
+# used just in case LLVM decides to use the `.` suffix.
+#
+# In the future, checking for the `.comment` section may be another
+# option, see https://github.com/rust-lang/rust/pull/97550.
+${NM} "$*" | grep -qE '^[0-9a-fA-F]+ r _R[^[:space:]]+16___IS_RUST_MODULE[^[:space:]]*$'
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index f18e6dfc68c5..3b64dda7e4cc 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -27,7 +27,17 @@
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof(arr[0]))
 
-#define KSYM_NAME_LEN		128
+#define _stringify_1(x)	#x
+#define _stringify(x)	_stringify_1(x)
+
+#define KSYM_NAME_LEN		512
+
+/* A substantially bigger size than the current maximum. */
+#define KSYM_NAME_LEN_BUFFER	2048
+_Static_assert(
+	KSYM_NAME_LEN_BUFFER == KSYM_NAME_LEN * 4,
+	"Please keep KSYM_NAME_LEN_BUFFER in sync with KSYM_NAME_LEN"
+);
 
 struct sym_entry {
 	unsigned long long addr;
@@ -198,15 +208,15 @@ static void check_symbol_range(const char *sym, unsigned long long addr,
 
 static struct sym_entry *read_symbol(FILE *in)
 {
-	char name[500], type;
+	char name[KSYM_NAME_LEN_BUFFER+1], type;
 	unsigned long long addr;
 	unsigned int len;
 	struct sym_entry *sym;
 	int rc;
 
-	rc = fscanf(in, "%llx %c %499s\n", &addr, &type, name);
+	rc = fscanf(in, "%llx %c %" _stringify(KSYM_NAME_LEN_BUFFER) "s\n", &addr, &type, name);
 	if (rc != 3) {
-		if (rc != EOF && fgets(name, 500, in) == NULL)
+		if (rc != EOF && fgets(name, sizeof(name), in) == NULL)
 			fprintf(stderr, "Read error or end of file.\n");
 		return NULL;
 	}
@@ -471,12 +481,35 @@ static void write_src(void)
 		if ((i & 0xFF) == 0)
 			markers[i >> 8] = off;
 
-		printf("\t.byte 0x%02x", table[i]->len);
+		/* There cannot be any symbol of length zero. */
+		if (table[i]->len == 0) {
+			fprintf(stderr, "kallsyms failure: "
+				"unexpected zero symbol length\n");
+			exit(EXIT_FAILURE);
+		}
+
+		/* Only lengths that fit in up-to-two-byte ULEB128 are supported. */
+		if (table[i]->len > 0x3FFF) {
+			fprintf(stderr, "kallsyms failure: "
+				"unexpected huge symbol length\n");
+			exit(EXIT_FAILURE);
+		}
+
+		/* Encode length with ULEB128. */
+		if (table[i]->len <= 0x7F) {
+			/* Most symbols use a single byte for the length. */
+			printf("\t.byte 0x%02x", table[i]->len);
+			off += table[i]->len + 1;
+		} else {
+			/* "Big" symbols use two bytes. */
+			printf("\t.byte 0x%02x, 0x%02x",
+				(table[i]->len & 0x7F) | 0x80,
+				(table[i]->len >> 7) & 0x7F);
+			off += table[i]->len + 2;
+		}
 		for (k = 0; k < table[i]->len; k++)
 			printf(", 0x%02x", table[i]->sym[k]);
 		printf("\n");
-
-		off += table[i]->len + 1;
 	}
 	printf("\n");
 
diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c
index c4340c90e172..b7c9f1dd5e42 100644
--- a/scripts/kconfig/confdata.c
+++ b/scripts/kconfig/confdata.c
@@ -216,6 +216,13 @@ static const char *conf_get_autoheader_name(void)
 	return name ? name : "include/generated/autoconf.h";
 }
 
+static const char *conf_get_rustccfg_name(void)
+{
+	char *name = getenv("KCONFIG_RUSTCCFG");
+
+	return name ? name : "include/generated/rustc_cfg";
+}
+
 static int conf_set_sym_val(struct symbol *sym, int def, int def_flags, char *p)
 {
 	char *p2;
@@ -605,6 +612,9 @@ static const struct comment_style comment_style_c = {
 
 static void conf_write_heading(FILE *fp, const struct comment_style *cs)
 {
+	if (!cs)
+		return;
+
 	fprintf(fp, "%s\n", cs->prefix);
 
 	fprintf(fp, "%s Automatically generated file; DO NOT EDIT.\n",
@@ -745,6 +755,65 @@ static void print_symbol_for_c(FILE *fp, struct symbol *sym)
 	free(escaped);
 }
 
+static void print_symbol_for_rustccfg(FILE *fp, struct symbol *sym)
+{
+	const char *val;
+	const char *val_prefix = "";
+	char *val_prefixed = NULL;
+	size_t val_prefixed_len;
+	char *escaped = NULL;
+
+	if (sym->type == S_UNKNOWN)
+		return;
+
+	val = sym_get_string_value(sym);
+
+	switch (sym->type) {
+	case S_BOOLEAN:
+	case S_TRISTATE:
+		/*
+		 * We do not care about disabled ones, i.e. no need for
+		 * what otherwise are "comments" in other printers.
+		 */
+		if (*val == 'n')
+			return;
+
+		/*
+		 * To have similar functionality to the C macro `IS_ENABLED()`
+		 * we provide an empty `--cfg CONFIG_X` here in both `y`
+		 * and `m` cases.
+		 *
+		 * Then, the common `fprintf()` below will also give us
+		 * a `--cfg CONFIG_X="y"` or `--cfg CONFIG_X="m"`, which can
+		 * be used as the equivalent of `IS_BUILTIN()`/`IS_MODULE()`.
+		 */
+		fprintf(fp, "--cfg=%s%s\n", CONFIG_, sym->name);
+		break;
+	case S_HEX:
+		if (val[0] != '0' || (val[1] != 'x' && val[1] != 'X'))
+			val_prefix = "0x";
+		break;
+	default:
+		break;
+	}
+
+	if (strlen(val_prefix) > 0) {
+		val_prefixed_len = strlen(val) + strlen(val_prefix) + 1;
+		val_prefixed = xmalloc(val_prefixed_len);
+		snprintf(val_prefixed, val_prefixed_len, "%s%s", val_prefix, val);
+		val = val_prefixed;
+	}
+
+	/* All values get escaped: the `--cfg` option only takes strings */
+	escaped = escape_string_value(val);
+	val = escaped;
+
+	fprintf(fp, "--cfg=%s%s=%s\n", CONFIG_, sym->name, val);
+
+	free(escaped);
+	free(val_prefixed);
+}
+
 /*
  * Write out a minimal config.
  * All values that has default values are skipped as this is redundant.
@@ -1132,6 +1201,12 @@ int conf_write_autoconf(int overwrite)
 	if (ret)
 		return ret;
 
+	ret = __conf_write_autoconf(conf_get_rustccfg_name(),
+				    print_symbol_for_rustccfg,
+				    NULL);
+	if (ret)
+		return ret;
+
 	/*
 	 * Create include/config/auto.conf. This must be the last step because
 	 * Kbuild has a dependency on auto.conf and this marks the successful
diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
index 250925aab101..b6593eac5003 100755
--- a/scripts/min-tool-version.sh
+++ b/scripts/min-tool-version.sh
@@ -30,6 +30,12 @@ llvm)
 		echo 11.0.0
 	fi
 	;;
+rustc)
+	echo 1.62.0
+	;;
+bindgen)
+	echo 0.56.0
+	;;
 *)
 	echo "$1: unknown tool" >&2
 	exit 1
diff --git a/scripts/rust-is-available-bindgen-libclang.h b/scripts/rust-is-available-bindgen-libclang.h
new file mode 100644
index 000000000000..0ef6db10d674
--- /dev/null
+++ b/scripts/rust-is-available-bindgen-libclang.h
@@ -0,0 +1,2 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#pragma message("clang version " __clang_version__)
diff --git a/scripts/rust-is-available.sh b/scripts/rust-is-available.sh
new file mode 100755
index 000000000000..0ddad3fcd32c
--- /dev/null
+++ b/scripts/rust-is-available.sh
@@ -0,0 +1,160 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Tests whether a suitable Rust toolchain is available.
+#
+# Pass `-v` for human output and more checks (as warnings).
+
+set -e
+
+min_tool_version=$(dirname $0)/min-tool-version.sh
+
+# Convert the version string x.y.z to a canonical up-to-7-digits form.
+#
+# Note that this function uses one more digit (compared to other
+# instances in other version scripts) to give a bit more space to
+# `rustc` since it will reach 1.100.0 in late 2026.
+get_canonical_version()
+{
+	IFS=.
+	set -- $1
+	echo $((100000 * $1 + 100 * $2 + $3))
+}
+
+# Check that the Rust compiler exists.
+if ! command -v "$RUSTC" >/dev/null; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Rust compiler '$RUSTC' could not be found."
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+
+# Check that the Rust bindings generator exists.
+if ! command -v "$BINDGEN" >/dev/null; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Rust bindings generator '$BINDGEN' could not be found."
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+
+# Check that the Rust compiler version is suitable.
+#
+# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
+rust_compiler_version=$( \
+	LC_ALL=C "$RUSTC" --version 2>/dev/null \
+		| head -n 1 \
+		| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
+)
+rust_compiler_min_version=$($min_tool_version rustc)
+rust_compiler_cversion=$(get_canonical_version $rust_compiler_version)
+rust_compiler_min_cversion=$(get_canonical_version $rust_compiler_min_version)
+if [ "$rust_compiler_cversion" -lt "$rust_compiler_min_cversion" ]; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Rust compiler '$RUSTC' is too old."
+		echo >&2 "***   Your version:    $rust_compiler_version"
+		echo >&2 "***   Minimum version: $rust_compiler_min_version"
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+if [ "$1" = -v ] && [ "$rust_compiler_cversion" -gt "$rust_compiler_min_cversion" ]; then
+	echo >&2 "***"
+	echo >&2 "*** Rust compiler '$RUSTC' is too new. This may or may not work."
+	echo >&2 "***   Your version:     $rust_compiler_version"
+	echo >&2 "***   Expected version: $rust_compiler_min_version"
+	echo >&2 "***"
+fi
+
+# Check that the Rust bindings generator is suitable.
+#
+# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
+rust_bindings_generator_version=$( \
+	LC_ALL=C "$BINDGEN" --version 2>/dev/null \
+		| head -n 1 \
+		| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
+)
+rust_bindings_generator_min_version=$($min_tool_version bindgen)
+rust_bindings_generator_cversion=$(get_canonical_version $rust_bindings_generator_version)
+rust_bindings_generator_min_cversion=$(get_canonical_version $rust_bindings_generator_min_version)
+if [ "$rust_bindings_generator_cversion" -lt "$rust_bindings_generator_min_cversion" ]; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Rust bindings generator '$BINDGEN' is too old."
+		echo >&2 "***   Your version:    $rust_bindings_generator_version"
+		echo >&2 "***   Minimum version: $rust_bindings_generator_min_version"
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+if [ "$1" = -v ] && [ "$rust_bindings_generator_cversion" -gt "$rust_bindings_generator_min_cversion" ]; then
+	echo >&2 "***"
+	echo >&2 "*** Rust bindings generator '$BINDGEN' is too new. This may or may not work."
+	echo >&2 "***   Your version:     $rust_bindings_generator_version"
+	echo >&2 "***   Expected version: $rust_bindings_generator_min_version"
+	echo >&2 "***"
+fi
+
+# Check that the `libclang` used by the Rust bindings generator is suitable.
+bindgen_libclang_version=$( \
+	LC_ALL=C "$BINDGEN" $(dirname $0)/rust-is-available-bindgen-libclang.h 2>&1 >/dev/null \
+		| grep -F 'clang version ' \
+		| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
+		| head -n 1 \
+)
+bindgen_libclang_min_version=$($min_tool_version llvm)
+bindgen_libclang_cversion=$(get_canonical_version $bindgen_libclang_version)
+bindgen_libclang_min_cversion=$(get_canonical_version $bindgen_libclang_min_version)
+if [ "$bindgen_libclang_cversion" -lt "$bindgen_libclang_min_cversion" ]; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN') is too old."
+		echo >&2 "***   Your version:    $bindgen_libclang_version"
+		echo >&2 "***   Minimum version: $bindgen_libclang_min_version"
+		echo >&2 "***"
+	fi
+	exit 1
+fi
+
+# If the C compiler is Clang, then we can also check whether its version
+# matches the `libclang` version used by the Rust bindings generator.
+#
+# In the future, we might be able to perform a full version check, see
+# https://github.com/rust-lang/rust-bindgen/issues/2138.
+if [ "$1" = -v ]; then
+	cc_name=$($(dirname $0)/cc-version.sh "$CC" | cut -f1 -d' ')
+	if [ "$cc_name" = Clang ]; then
+		clang_version=$( \
+			LC_ALL=C "$CC" --version 2>/dev/null \
+				| sed -nE '1s:.*version ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
+		)
+		if [ "$clang_version" != "$bindgen_libclang_version" ]; then
+			echo >&2 "***"
+			echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN')"
+			echo >&2 "*** version does not match Clang's. This may be a problem."
+			echo >&2 "***   libclang version: $bindgen_libclang_version"
+			echo >&2 "***   Clang version:    $clang_version"
+			echo >&2 "***"
+		fi
+	fi
+fi
+
+# Check that the source code for the `core` standard library exists.
+#
+# `$KRUSTFLAGS` is passed in case the user added `--sysroot`.
+rustc_sysroot=$("$RUSTC" $KRUSTFLAGS --print sysroot)
+rustc_src=${RUST_LIB_SRC:-"$rustc_sysroot/lib/rustlib/src/rust/library"}
+rustc_src_core="$rustc_src/core/src/lib.rs"
+if [ ! -e "$rustc_src_core" ]; then
+	if [ "$1" = -v ]; then
+		echo >&2 "***"
+		echo >&2 "*** Source code for the 'core' standard library could not be found"
+		echo >&2 "*** at '$rustc_src_core'."
+		echo >&2 "***"
+	fi
+	exit 1
+fi
diff --git a/scripts/rustdoc_test_builder.py b/scripts/rustdoc_test_builder.py
new file mode 100755
index 000000000000..d9b47a5c54fc
--- /dev/null
+++ b/scripts/rustdoc_test_builder.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+"""rustdoc_test_builder - Test builder for `rustdoc`-generated tests.
+"""
+
+import json
+import pathlib
+import re
+import sys
+
+RUST_DIR = pathlib.Path("rust")
+TESTS_DIR = RUST_DIR / "test" / "doctests" / "kernel"
+
+# `[^\s]*` removes the prefix (e.g. `_doctest_main_`) plus any
+# leading path (for `O=` builds).
+MAIN_RE = re.compile(
+    r"^"
+    r"fn main\(\) { "
+    r"#\[allow\(non_snake_case\)\] "
+    r"fn ([^\s]*rust_kernel_([a-zA-Z0-9_]+))\(\) {"
+    r"$"
+)
+
+def main():
+    found_main = False
+    test_header = ""
+    test_body = ""
+    for line in sys.stdin.readlines():
+        main_match = MAIN_RE.match(line)
+        if main_match:
+            if found_main:
+                raise Exception("More than one `main` line found.")
+            found_main = True
+            function_name = main_match.group(1)
+            test_name = f"rust_kernel_doctest_{main_match.group(2)}"
+            continue
+
+        if found_main:
+            test_body += line
+        else:
+            test_header += line
+
+    if not found_main:
+        raise Exception("No `main` line found.")
+
+    call_line = f"}} {function_name}() }}"
+    if not test_body.endswith(call_line):
+        raise Exception("Unexpected end of test body.")
+    test_body = test_body[:-len(call_line)]
+
+    with open(TESTS_DIR / f"{test_name}.json", "w") as fd:
+        json.dump({
+            "name": test_name,
+            "header": test_header,
+            "body": test_body,
+        }, fd, sort_keys=True, indent=4)
+
+if __name__ == "__main__":
+    main()
diff --git a/scripts/rustdoc_test_gen.py b/scripts/rustdoc_test_gen.py
new file mode 100755
index 000000000000..ad9a94293ab5
--- /dev/null
+++ b/scripts/rustdoc_test_gen.py
@@ -0,0 +1,164 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+"""rustdoc_test_gen - Generates KUnit tests from saved `rustdoc`-generated tests.
+"""
+
+import json
+import os
+import pathlib
+
+RUST_DIR = pathlib.Path("rust")
+TESTS_DIR = RUST_DIR / "test" / "doctests" / "kernel"
+
+RUST_FILE = RUST_DIR / "doctests_kernel_generated.rs"
+C_FILE = RUST_DIR / "doctests_kernel_generated_kunit.c"
+
+RUST_TEMPLATE_TEST = """
+/// Generated `{test_name}` KUnit test case from a Rust documentation test.
+#[no_mangle]
+pub fn {test_name}(__kunit_test: *mut kernel::bindings::kunit) {{
+    /// Provides mutual exclusion (see `# Implementation` notes).
+    static __KUNIT_TEST_MUTEX: kernel::sync::smutex::Mutex<()> =
+        kernel::sync::smutex::Mutex::new(());
+
+    /// Saved argument (see `# Implementation` notes).
+    static __KUNIT_TEST: core::sync::atomic::AtomicPtr<kernel::bindings::kunit> =
+        core::sync::atomic::AtomicPtr::new(core::ptr::null_mut());
+
+    let __kunit_test_mutex_guard = __KUNIT_TEST_MUTEX.lock();
+    __KUNIT_TEST.store(__kunit_test, core::sync::atomic::Ordering::SeqCst);
+
+    /// Overrides the usual [`assert!`] macro with one that calls KUnit instead.
+    macro_rules! assert {{
+        ($cond:expr $(,)?) => {{{{
+            kernel::kunit_assert!(
+                __KUNIT_TEST.load(core::sync::atomic::Ordering::SeqCst),
+                $cond
+            );
+        }}}}
+    }}
+
+    /// Overrides the usual [`assert_eq!`] macro with one that calls KUnit instead.
+    macro_rules! assert_eq {{
+        ($left:expr, $right:expr $(,)?) => {{{{
+            kernel::kunit_assert_eq!(
+                __KUNIT_TEST.load(core::sync::atomic::Ordering::SeqCst),
+                $left,
+                $right
+            );
+        }}}}
+    }}
+
+    // Many tests need the prelude, so provide it by default.
+    use kernel::prelude::*;
+
+    {test_body}
+}}
+"""
+RUST_TEMPLATE = """// SPDX-License-Identifier: GPL-2.0
+
+//! `kernel` crate documentation tests.
+
+// # Implementation
+//
+// KUnit gives us a context in the form of the `kunit_test` parameter that one
+// needs to pass back to other KUnit functions and macros.
+//
+// However, we want to keep this as an implementation detail because:
+//
+//   - Test code should not care about the implementation.
+//
+//   - Documentation looks worse if it needs to carry extra details unrelated
+//     to the piece being described.
+//
+//   - Test code should be able to define functions and call them, without
+//     having to carry the context (since functions cannot capture dynamic
+//     environment).
+//
+//   - Later on, we may want to be able to test non-kernel code (e.g. `core`,
+//     `alloc` or external crates) which likely use the standard library
+//     `assert*!` macros.
+//
+// For this reason, `static`s are used in the generated code to save the
+// argument which then gets read by the asserting macros. These macros then
+// call back into KUnit, instead of panicking.
+//
+// To avoid depending on whether KUnit allows to run tests concurrently and/or
+// reentrantly, we ensure mutual exclusion on our end. To ensure a single test
+// being killed does not trigger failure of every other test (timing out),
+// we provide different `static`s per test (which also allow for concurrent
+// execution, though KUnit runs them sequentially).
+//
+// Furthermore, since test code may create threads and assert from them, we use
+// an `AtomicPtr` to hold the context (though each test only writes once before
+// threads may be created).
+
+{rust_header}
+
+const __LOG_PREFIX: &[u8] = b"rust_kernel_doctests\\0";
+
+{rust_tests}
+"""
+
+C_TEMPLATE_TEST_DECLARATION = "void {test_name}(struct kunit *);\n"
+C_TEMPLATE_TEST_CASE = "    KUNIT_CASE({test_name}),\n"
+C_TEMPLATE = """// SPDX-License-Identifier: GPL-2.0
+/*
+ * `kernel` crate documentation tests.
+ */
+
+#include <kunit/test.h>
+
+{c_test_declarations}
+
+static struct kunit_case test_cases[] = {{
+    {c_test_cases}
+    {{ }}
+}};
+
+static struct kunit_suite test_suite = {{
+    .name = "rust_kernel_doctests",
+    .test_cases = test_cases,
+}};
+
+kunit_test_suite(test_suite);
+
+MODULE_LICENSE("GPL");
+"""
+
+def main():
+    rust_header = set()
+    rust_tests = ""
+    c_test_declarations = ""
+    c_test_cases = ""
+    for filename in sorted(os.listdir(TESTS_DIR)):
+        with open(TESTS_DIR / filename, "r") as fd:
+            test = json.load(fd)
+            for line in test["header"].strip().split("\n"):
+                rust_header.add(line)
+            rust_tests += RUST_TEMPLATE_TEST.format(
+                test_name = test["name"],
+                test_body = test["body"]
+            )
+            c_test_declarations += C_TEMPLATE_TEST_DECLARATION.format(
+                test_name = test["name"]
+            )
+            c_test_cases += C_TEMPLATE_TEST_CASE.format(
+                test_name = test["name"]
+            )
+    rust_header = sorted(rust_header)
+
+    with open(RUST_FILE, "w") as fd:
+        fd.write(RUST_TEMPLATE.format(
+            rust_header = "\n".join(rust_header).strip(),
+            rust_tests = rust_tests.strip(),
+        ))
+
+    with open(C_FILE, "w") as fd:
+        fd.write(C_TEMPLATE.format(
+            c_test_declarations=c_test_declarations.strip(),
+            c_test_cases=c_test_cases.strip(),
+        ))
+
+if __name__ == "__main__":
+    main()
diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h
index efb6c3f5f2a9..5a37ccbec54f 100644
--- a/tools/include/linux/kallsyms.h
+++ b/tools/include/linux/kallsyms.h
@@ -6,7 +6,7 @@
 #include <stdio.h>
 #include <unistd.h>
 
-#define KSYM_NAME_LEN 128
+#define KSYM_NAME_LEN 512
 
 struct module;
 
diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
index 556bb06798f2..3ac4874082f8 100644
--- a/tools/lib/perf/include/perf/event.h
+++ b/tools/lib/perf/include/perf/event.h
@@ -95,7 +95,7 @@ struct perf_record_throttle {
 };
 
 #ifndef KSYM_NAME_LEN
-#define KSYM_NAME_LEN 256
+#define KSYM_NAME_LEN 512
 #endif
 
 struct perf_record_ksymbol {
diff --git a/tools/lib/symbol/kallsyms.h b/tools/lib/symbol/kallsyms.h
index 72ab9870454b..542f9b059c3b 100644
--- a/tools/lib/symbol/kallsyms.h
+++ b/tools/lib/symbol/kallsyms.h
@@ -7,7 +7,7 @@
 #include <linux/types.h>
 
 #ifndef KSYM_NAME_LEN
-#define KSYM_NAME_LEN 256
+#define KSYM_NAME_LEN 512
 #endif
 
 static inline u8 kallsyms2elf_binding(char type)