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authorH. Peter Anvin <hpa@linux.intel.com>2011-11-17 13:17:35 -0800
committerH. Peter Anvin <hpa@linux.intel.com>2011-11-17 13:35:20 -0800
commit052ad274964e613a12bf8ce7c5631f70d0bc82cc (patch)
treefd3519410801d766f63b07dc308d2b702f3c9ec0 /Documentation/kbuild/makefiles.txt
parentcb97914b04e7b587cf555ec5b1c69d61014f3378 (diff)
kbuild: Add support for an "archheaders" target
Add support for an "archheaders" target. This target can generate files that need to be installed for user space by "make headers_install" or "make headers_install_all". In order to support "make headers_install_all", it must be able to run without the tree having to be configured first. Cc: David Woodhouse <dwmw2@infradead.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Michal Marek <mmarek@suse.cz> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'Documentation/kbuild/makefiles.txt')
-rw-r--r--Documentation/kbuild/makefiles.txt50
1 files changed, 32 insertions, 18 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index f47cdefb4d1e..ab0a984530d8 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -33,14 +33,15 @@ This document describes the Linux kernel Makefiles.
=== 6 Architecture Makefiles
--- 6.1 Set variables to tweak the build to the architecture
- --- 6.2 Add prerequisites to archprepare:
- --- 6.3 List directories to visit when descending
- --- 6.4 Architecture-specific boot images
- --- 6.5 Building non-kbuild targets
- --- 6.6 Commands useful for building a boot image
- --- 6.7 Custom kbuild commands
- --- 6.8 Preprocessing linker scripts
- --- 6.9 Generic header files
+ --- 6.2 Add prerequisites to archheaders:
+ --- 6.3 Add prerequisites to archprepare:
+ --- 6.4 List directories to visit when descending
+ --- 6.5 Architecture-specific boot images
+ --- 6.6 Building non-kbuild targets
+ --- 6.7 Commands useful for building a boot image
+ --- 6.8 Custom kbuild commands
+ --- 6.9 Preprocessing linker scripts
+ --- 6.10 Generic header files
=== 7 Kbuild syntax for exported headers
--- 7.1 header-y
@@ -252,7 +253,7 @@ more details, with real examples.
This will create a library lib.a based on delay.o. For kbuild to
actually recognize that there is a lib.a being built, the directory
shall be listed in libs-y.
- See also "6.3 List directories to visit when descending".
+ See also "6.4 List directories to visit when descending".
Use of lib-y is normally restricted to lib/ and arch/*/lib.
@@ -974,7 +975,20 @@ When kbuild executes, the following steps are followed (roughly):
$(KBUILD_ARFLAGS) set by the top level Makefile to "D" (deterministic
mode) if this option is supported by $(AR).
---- 6.2 Add prerequisites to archprepare:
+--- 6.2 Add prerequisites to archheaders:
+
+ The archheaders: rule is used to generate header files that
+ may be installed into user space by "make header_install" or
+ "make headers_install_all". In order to support
+ "make headers_install_all", this target has to be able to run
+ on an unconfigured tree, or a tree configured for another
+ architecture.
+
+ It is run before "make archprepare" when run on the
+ architecture itself.
+
+
+--- 6.3 Add prerequisites to archprepare:
The archprepare: rule is used to list prerequisites that need to be
built before starting to descend down in the subdirectories.
@@ -990,7 +1004,7 @@ When kbuild executes, the following steps are followed (roughly):
generating offset header files.
---- 6.3 List directories to visit when descending
+--- 6.4 List directories to visit when descending
An arch Makefile cooperates with the top Makefile to define variables
which specify how to build the vmlinux file. Note that there is no
@@ -1019,7 +1033,7 @@ When kbuild executes, the following steps are followed (roughly):
drivers-$(CONFIG_OPROFILE) += arch/sparc64/oprofile/
---- 6.4 Architecture-specific boot images
+--- 6.5 Architecture-specific boot images
An arch Makefile specifies goals that take the vmlinux file, compress
it, wrap it in bootstrapping code, and copy the resulting files
@@ -1070,7 +1084,7 @@ When kbuild executes, the following steps are followed (roughly):
When "make" is executed without arguments, bzImage will be built.
---- 6.5 Building non-kbuild targets
+--- 6.6 Building non-kbuild targets
extra-y
@@ -1090,7 +1104,7 @@ When kbuild executes, the following steps are followed (roughly):
shall be built, but shall not be linked as part of built-in.o.
---- 6.6 Commands useful for building a boot image
+--- 6.7 Commands useful for building a boot image
Kbuild provides a few macros that are useful when building a
boot image.
@@ -1112,7 +1126,7 @@ When kbuild executes, the following steps are followed (roughly):
always be built.
Assignments to $(targets) are without $(obj)/ prefix.
if_changed may be used in conjunction with custom commands as
- defined in 6.7 "Custom kbuild commands".
+ defined in 6.8 "Custom kbuild commands".
Note: It is a typical mistake to forget the FORCE prerequisite.
Another common pitfall is that whitespace is sometimes
@@ -1171,7 +1185,7 @@ When kbuild executes, the following steps are followed (roughly):
$(obj)/%.dtb: $(src)/%.dts
$(call cmd,dtc)
---- 6.7 Custom kbuild commands
+--- 6.8 Custom kbuild commands
When kbuild is executing with KBUILD_VERBOSE=0, then only a shorthand
of a command is normally displayed.
@@ -1198,7 +1212,7 @@ When kbuild executes, the following steps are followed (roughly):
will be displayed with "make KBUILD_VERBOSE=0".
---- 6.8 Preprocessing linker scripts
+--- 6.9 Preprocessing linker scripts
When the vmlinux image is built, the linker script
arch/$(ARCH)/kernel/vmlinux.lds is used.
@@ -1228,7 +1242,7 @@ When kbuild executes, the following steps are followed (roughly):
The kbuild infrastructure for *lds file are used in several
architecture-specific files.
---- 6.9 Generic header files
+--- 6.10 Generic header files
The directory include/asm-generic contains the header files
that may be shared between individual architectures.