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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-11-30 10:05:26 +0900 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-12-01 23:13:14 +0900 |
| commit | bbda5ec671d3fe62faefa1cab7270aa586042a4b (patch) | |
| tree | a1d375f74ad25efd2797bffaadfb0dc5fc1f65fe /include/asm-generic | |
| parent | ee3e46b7efd2954479f87030d31fda3c22bbc763 (diff) | |
| download | linux-0-day-bbda5ec671d3fe62faefa1cab7270aa586042a4b.tar.gz linux-0-day-bbda5ec671d3fe62faefa1cab7270aa586042a4b.tar.xz | |
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 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/export.h | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h index 4d73e6e3c66c6..294d6ae785d4e 100644 --- a/include/asm-generic/export.h +++ b/include/asm-generic/export.h @@ -59,16 +59,19 @@ __kcrctab_\name: .endm #undef __put -#if defined(__KSYM_DEPS__) - -#define __EXPORT_SYMBOL(sym, val, sec) === __KSYM_##sym === - -#elif defined(CONFIG_TRIM_UNUSED_KSYMS) +#if defined(CONFIG_TRIM_UNUSED_KSYMS) #include <linux/kconfig.h> #include <generated/autoksyms.h> +.macro __ksym_marker sym + .section ".discard.ksym","a" +__ksym_marker_\sym: + .previous +.endm + #define __EXPORT_SYMBOL(sym, val, sec) \ + __ksym_marker sym; \ __cond_export_sym(sym, val, sec, __is_defined(__KSYM_##sym)) #define __cond_export_sym(sym, val, sec, conf) \ ___cond_export_sym(sym, val, sec, conf) |