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authorMarco Elver <elver@google.com>2021-02-25 17:19:03 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2021-02-26 09:41:02 -0800
commit840b239863449f27bf7522deb81e6746fbfbfeaf (patch)
tree58e18efc0e9347043e856291e6557b28e6e1fa17 /arch
parent1dc0da6e9ec0f8d735756374697912cd50f402cf (diff)
downloadlinux-840b239863449f27bf7522deb81e6746fbfbfeaf.tar.gz
arm64, kfence: enable KFENCE for ARM64
Add architecture specific implementation details for KFENCE and enable KFENCE for the arm64 architecture. In particular, this implements the required interface in <asm/kfence.h>. KFENCE requires that attributes for pages from its memory pool can individually be set. Therefore, force the entire linear map to be mapped at page granularity. Doing so may result in extra memory allocated for page tables in case rodata=full is not set; however, currently CONFIG_RODATA_FULL_DEFAULT_ENABLED=y is the default, and the common case is therefore not affected by this change. [elver@google.com: add missing copyright and description header] Link: https://lkml.kernel.org/r/20210118092159.145934-3-elver@google.com Link: https://lkml.kernel.org/r/20201103175841.3495947-4-elver@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Signed-off-by: Marco Elver <elver@google.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Co-developed-by: Alexander Potapenko <glider@google.com> Reviewed-by: Jann Horn <jannh@google.com> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christopher Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Hillf Danton <hdanton@sina.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Joern Engel <joern@purestorage.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: SeongJae Park <sjpark@amazon.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/Kconfig1
-rw-r--r--arch/arm64/include/asm/kfence.h24
-rw-r--r--arch/arm64/mm/fault.c4
-rw-r--r--arch/arm64/mm/mmu.c8
4 files changed, 36 insertions, 1 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index fc0ce2a1f3bf..a254f4871683 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -140,6 +140,7 @@ config ARM64
select HAVE_ARCH_KASAN if !(ARM64_16K_PAGES && ARM64_VA_BITS_48)
select HAVE_ARCH_KASAN_SW_TAGS if HAVE_ARCH_KASAN
select HAVE_ARCH_KASAN_HW_TAGS if (HAVE_ARCH_KASAN && ARM64_MTE)
+ select HAVE_ARCH_KFENCE
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
diff --git a/arch/arm64/include/asm/kfence.h b/arch/arm64/include/asm/kfence.h
new file mode 100644
index 000000000000..42a06f83850a
--- /dev/null
+++ b/arch/arm64/include/asm/kfence.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * arm64 KFENCE support.
+ *
+ * Copyright (C) 2020, Google LLC.
+ */
+
+#ifndef __ASM_KFENCE_H
+#define __ASM_KFENCE_H
+
+#include <asm/cacheflush.h>
+
+#define KFENCE_SKIP_ARCH_FAULT_HANDLER "el1_sync"
+
+static inline bool arch_kfence_init_pool(void) { return true; }
+
+static inline bool kfence_protect_page(unsigned long addr, bool protect)
+{
+ set_memory_valid(addr, 1, !protect);
+
+ return true;
+}
+
+#endif /* __ASM_KFENCE_H */
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index dc9f96442edc..42515900ab2e 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -10,6 +10,7 @@
#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/extable.h>
+#include <linux/kfence.h>
#include <linux/signal.h>
#include <linux/mm.h>
#include <linux/hardirq.h>
@@ -389,6 +390,9 @@ static void __do_kernel_fault(unsigned long addr, unsigned int esr,
} else if (addr < PAGE_SIZE) {
msg = "NULL pointer dereference";
} else {
+ if (kfence_handle_page_fault(addr))
+ return;
+
msg = "paging request";
}
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index d0758d24a42d..ef7698c4e2f0 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -1465,7 +1465,13 @@ int arch_add_memory(int nid, u64 start, u64 size,
int ret, flags = 0;
VM_BUG_ON(!mhp_range_allowed(start, size, true));
- if (rodata_full || debug_pagealloc_enabled())
+
+ /*
+ * KFENCE requires linear map to be mapped at page granularity, so that
+ * it is possible to protect/unprotect single pages in the KFENCE pool.
+ */
+ if (rodata_full || debug_pagealloc_enabled() ||
+ IS_ENABLED(CONFIG_KFENCE))
flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
__create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),