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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-10 17:48:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-10 17:48:21 -0700
commitffd602eb4693bbb49b301fa059b109bbdebf9524 (patch)
treea7be15ffb7fe1a23dde4dc2831670f3abed6ce95 /Documentation/kbuild/makefiles.txt
parentMerge branch 'next-tpm' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security (diff)
parentkbuild: remove scripts/basic/% build target (diff)
downloadlinux-dev-ffd602eb4693bbb49b301fa059b109bbdebf9524.tar.xz
linux-dev-ffd602eb4693bbb49b301fa059b109bbdebf9524.zip
Merge tag 'kbuild-v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada: - do not generate unneeded top-level built-in.a - let git ignore O= directory entirely - optimize scripts/kallsyms slightly - exclude DWARF info from *.s regardless of config options - fix GCC toolchain search path for Clang to prepare ld.lld support - do not generate modules.order when CONFIG_MODULES is disabled - simplify single target rules and remove VPATH for external module build - allow to add optional flags to dpkg-buildpackage when building deb-pkg - move some compiler option tests from Makefile to Kconfig - various Makefile cleanups * tag 'kbuild-v5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (40 commits) kbuild: remove scripts/basic/% build target kbuild: use -Werror=implicit-... instead of -Werror-implicit-... kbuild: clean up scripts/gcc-version.sh kbuild: remove cc-version macro kbuild: update comment block of scripts/clang-version.sh kbuild: remove commented-out INITRD_COMPRESS kbuild: move -gsplit-dwarf, -gdwarf-4 option tests to Kconfig kbuild: [bin]deb-pkg: add DPKG_FLAGS variable kbuild: move ".config not found!" message from Kconfig to Makefile kbuild: invoke syncconfig if include/config/auto.conf.cmd is missing kbuild: simplify single target rules kbuild: remove empty rules for makefiles kbuild: make -r/-R effective in top Makefile for old Make versions kbuild: move tools_silent to a more relevant place kbuild: compute false-positive -Wmaybe-uninitialized cases in Kconfig kbuild: refactor cc-cross-prefix implementation kbuild: hardcode genksyms path and remove GENKSYMS variable scripts/gdb: refactor rules for symlink creation kbuild: create symlink to vmlinux-gdb.py in scripts_gdb target scripts/gdb: do not descend into scripts/gdb from scripts ...
Diffstat (limited to 'Documentation/kbuild/makefiles.txt')
-rw-r--r--Documentation/kbuild/makefiles.txt26
1 files changed, 2 insertions, 24 deletions
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index bf28c47bfd72..f124be6e4c3a 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -154,13 +154,8 @@ more details, with real examples.
Kbuild compiles all the $(obj-y) files. It then calls
"$(AR) rcSTP" to merge these files into one built-in.a file.
- This is a thin archive without a symbol table, which makes it
- unsuitable as a linker input.
-
- The scripts/link-vmlinux.sh script later makes an aggregate
- built-in.a with "${AR} rcsTP", which creates the thin archive
- with a symbol table and an index, making it a valid input for
- the final vmlinux link passes.
+ This is a thin archive without a symbol table. It will be later
+ linked into vmlinux by scripts/link-vmlinux.sh
The order of files in $(obj-y) is significant. Duplicates in
the lists are allowed: the first instance will be linked into
@@ -504,23 +499,6 @@ more details, with real examples.
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
- gcc 3.41 would return 0341.
- cc-version is useful when a specific $(CC) version is faulty in one
- area, for example -mregparm=3 was broken in some gcc versions
- even though the option was accepted by gcc.
-
- Example:
- #arch/x86/Makefile
- cflags-y += $(shell \
- if [ $(cc-version) -ge 0300 ] ; then \
- echo "-mregparm=3"; fi ;)
-
- In the above example, -mregparm=3 is only used for gcc version greater
- than or equal to gcc 3.0.
-
cc-ifversion
cc-ifversion tests the version of $(CC) and equals the fourth parameter
if version expression is true, or the fifth (if given) if the version