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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-11-30 02:05:26 +0100 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-12-01 15:13:14 +0100 |
| commit | bbda5ec671d3fe62faefa1cab7270aa586042a4b (patch) | |
| tree | a1d375f74ad25efd2797bffaadfb0dc5fc1f65fe /scripts/Makefile.build | |
| parent | kbuild: refactor modversions build rules (diff) | |
| download | linux-bbda5ec671d3fe62faefa1cab7270aa586042a4b.tar.xz linux-bbda5ec671d3fe62faefa1cab7270aa586042a4b.zip | |
kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS
My main motivation of this commit is to clean up scripts/Kbuild.include
and scripts/Makefile.build.
Currently, CONFIG_TRIM_UNUSED_KSYMS works with a tricky gimmick;
possibly exported symbols are detected by letting $(CPP) replace
EXPORT_SYMBOL* with a special string '=== __KSYM_*===', which is
post-processed by sed, and passed to fixdep. The extra preprocessing
is costly, and hacking cmd_and_fixdep is ugly.
I came up with a new way to find exported symbols; insert a dummy
symbol __ksym_marker_* to each potentially exported symbol. Those
dummy symbols are picked up by $(NM), post-processed by sed, then
appended to .*.cmd files. I collected the post-process part to a
new shell script scripts/gen_ksymdeps.sh for readability. The dummy
symbols are put into the .discard.* section so that the linker
script rips them off the final vmlinux or modules.
A nice side-effect is building with CONFIG_TRIM_UNUSED_KSYMS will
be much faster.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>
Diffstat (limited to 'scripts/Makefile.build')
| -rw-r--r-- | scripts/Makefile.build | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index cdb25d163b42..23ebf2508234 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -254,9 +254,15 @@ objtool_dep = $(objtool_obj) \ $(wildcard include/config/orc/unwinder.h \ include/config/stack/validation.h) +ifdef CONFIG_TRIM_UNUSED_KSYMS +cmd_gen_ksymdeps = \ + $(CONFIG_SHELL) $(srctree)/scripts/gen_ksymdeps.sh $@ >> $(dot-target).cmd; +endif + define rule_cc_o_c $(call echo-cmd,checksrc) $(cmd_checksrc) \ $(call cmd_and_fixdep,cc_o_c) \ + $(cmd_gen_ksymdeps) \ $(cmd_checkdoc) \ $(call echo-cmd,objtool) $(cmd_objtool) \ $(cmd_modversions_c) \ @@ -265,6 +271,7 @@ endef define rule_as_o_S $(call cmd_and_fixdep,as_o_S) \ + $(cmd_gen_ksymdeps) \ $(call echo-cmd,objtool) $(cmd_objtool) \ $(cmd_modversions_S) endef |