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author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-24 22:31:37 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-24 22:31:37 +0200 |
commit | 2bb732cdb48d271ff7a910260ffb851fb4bc8a28 (patch) | |
tree | 580bf68eb1e52b4e6915588d61423347ae09c318 /Documentation/kbuild | |
parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 (diff) | |
parent | kbuild: make KBUILD_NOCMDDEP=1 handle empty built-in.o (diff) | |
download | linux-2bb732cdb48d271ff7a910260ffb851fb4bc8a28.tar.xz linux-2bb732cdb48d271ff7a910260ffb851fb4bc8a28.zip |
Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild-2.6:
kbuild: make KBUILD_NOCMDDEP=1 handle empty built-in.o
scripts/kallsyms.c: fix potential segfault
scripts/gen_initramfs_list.sh: Convert to a /bin/sh script
kbuild: Fix GNU make v3.80 compatibility
kbuild: Fix passing -Wno-* options to gcc 4.4+
kbuild: move scripts/basic/docproc.c to scripts/docproc.c
kbuild: Fix Makefile.asm-generic for um
kbuild: Allow to combine multiple W= levels
kbuild: Disable -Wunused-but-set-variable for gcc 4.6.0
Fix handling of backlash character in LINUX_COMPILE_BY name
kbuild: asm-generic support
kbuild: implement several W= levels
kbuild: Fix build with binutils <= 2.19
initramfs: Use KBUILD_BUILD_TIMESTAMP for generated entries
kbuild: Allow to override LINUX_COMPILE_BY and LINUX_COMPILE_HOST macros
kbuild: Drop unused LINUX_COMPILE_TIME and LINUX_COMPILE_DOMAIN macros
kbuild: Use the deterministic mode of ar
kbuild: Call gzip with -n
kbuild: move KALLSYMS_EXTRA_PASS from Kconfig to Makefile
Kconfig: improve KALLSYMS_ALL documentation
Fix up trivial conflict in Makefile
Diffstat (limited to 'Documentation/kbuild')
-rw-r--r-- | Documentation/kbuild/kbuild.txt | 13 | ||||
-rw-r--r-- | Documentation/kbuild/makefiles.txt | 53 |
2 files changed, 66 insertions, 0 deletions
diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt index 7c2a89ba674c..68e32bb6bd80 100644 --- a/Documentation/kbuild/kbuild.txt +++ b/Documentation/kbuild/kbuild.txt @@ -201,3 +201,16 @@ KBUILD_ENABLE_EXTRA_GCC_CHECKS -------------------------------------------------- If enabled over the make command line with "W=1", it turns on additional gcc -W... options for more extensive build-time checking. + +KBUILD_BUILD_TIMESTAMP +-------------------------------------------------- +Setting this to a date string overrides the timestamp used in the +UTS_VERSION definition (uname -v in the running kernel). The value has to +be a string that can be passed to date -d. The default value +is the output of the date command at one point during build. + +KBUILD_BUILD_USER, KBUILD_BUILD_HOST +-------------------------------------------------- +These two variables allow to override the user@host string displayed during +boot and in /proc/version. The default value is the output of the commands +whoami and host, respectively. diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt index 5d145bb443c0..47435e56c5da 100644 --- a/Documentation/kbuild/makefiles.txt +++ b/Documentation/kbuild/makefiles.txt @@ -40,11 +40,13 @@ This document describes the Linux kernel Makefiles. --- 6.6 Commands useful for building a boot image --- 6.7 Custom kbuild commands --- 6.8 Preprocessing linker scripts + --- 6.9 Generic header files === 7 Kbuild syntax for exported headers --- 7.1 header-y --- 7.2 objhdr-y --- 7.3 destination-y + --- 7.4 generic-y === 8 Kbuild Variables === 9 Makefile language @@ -499,6 +501,18 @@ more details, with real examples. gcc >= 3.00. For gcc < 3.00, -malign-functions=4 is used. Note: cc-option-align uses KBUILD_CFLAGS for $(CC) options + cc-disable-warning + cc-disable-warning checks if gcc supports a given warning and returns + the commandline switch to disable it. This special function is needed, + because gcc 4.4 and later accept any unknown -Wno-* option and only + warn about it if there is another warning in the source file. + + Example: + KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable) + + In the above example, -Wno-unused-but-set-variable will be added to + KBUILD_CFLAGS only if gcc really accepts it. + cc-version cc-version returns a numerical version of the $(CC) compiler version. The format is <major><minor> where both are two digits. So for example @@ -955,6 +969,11 @@ When kbuild executes, the following steps are followed (roughly): used when linking modules. This is often a linker script. From commandline LDFLAGS_MODULE shall be used (see kbuild.txt). + KBUILD_ARFLAGS Options for $(AR) when creating archives + + $(KBUILD_ARFLAGS) set by the top level Makefile to "D" (deterministic + mode) if this option is supported by $(AR). + --- 6.2 Add prerequisites to archprepare: The archprepare: rule is used to list prerequisites that need to be @@ -1209,6 +1228,14 @@ When kbuild executes, the following steps are followed (roughly): The kbuild infrastructure for *lds file are used in several architecture-specific files. +--- 6.9 Generic header files + + The directory include/asm-generic contains the header files + that may be shared between individual architectures. + The recommended approach how to use a generic header file is + to list the file in the Kbuild file. + See "7.4 generic-y" for further info on syntax etc. + === 7 Kbuild syntax for exported headers The kernel include a set of headers that is exported to userspace. @@ -1265,6 +1292,32 @@ See subsequent chapter for the syntax of the Kbuild file. In the example above all exported headers in the Kbuild file will be located in the directory "include/linux" when exported. + --- 7.4 generic-y + + If an architecture uses a verbatim copy of a header from + include/asm-generic then this is listed in the file + arch/$(ARCH)/include/asm/Kbuild like this: + + Example: + #arch/x86/include/asm/Kbuild + generic-y += termios.h + generic-y += rtc.h + + During the prepare phase of the build a wrapper include + file is generated in the directory: + + arch/$(ARCH)/include/generated/asm + + When a header is exported where the architecture uses + the generic header a similar wrapper is generated as part + of the set of exported headers in the directory: + + usr/include/asm + + The generated wrapper will in both cases look like the following: + + Example: termios.h + #include <asm-generic/termios.h> === 8 Kbuild Variables |