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| author |   Masahiro Yamada <yamada.masahiro@socionext.com> | 2019-01-03 15:26:20 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2019-01-04 13:13:45 -0800 |
| commit | c60d3b79423aab402085c30b33bfff5354a61d8b (patch) | |
| tree | de72c302ae424ec617c5221306b637badd2656d2 /include/linux | |
| parent | Documentation/process/coding-style.rst: don't use "extern" with function prototypes (diff) | |
| download | linux-dev-c60d3b79423aab402085c30b33bfff5354a61d8b.tar.xz linux-dev-c60d3b79423aab402085c30b33bfff5354a61d8b.zip | |
build_bug.h: remove negative-array fallback for BUILD_BUG_ON()
The kernel can only be compiled with an optimization option (-O2, -Os,
or the currently proposed -Og). Hence, __OPTIMIZE__ is always defined
in the kernel source.
The fallback for the -O0 case is just hypothetical and pointless.
Moreover, commit 0bb95f80a38f ("Makefile: Globally enable VLA warning")
enabled -Wvla warning. The use of variable length arrays is banned.
Link: http://lkml.kernel.org/r/1542856462-18836-2-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/build_bug.h | 14 |
1 files changed, 0 insertions, 14 deletions
diff --git a/include/linux/build_bug.h b/include/linux/build_bug.h index 43d1fd50d433..d415c6431441 100644 --- a/include/linux/build_bug.h +++ b/include/linux/build_bug.h @@ -51,23 +51,9 @@ * If you have some code which relies on certain constants being equal, or * some other compile-time-evaluated condition, you should use BUILD_BUG_ON to * detect if someone changes it. - * - * The implementation uses gcc's reluctance to create a negative array, but gcc - * (as of 4.4) only emits that error for obvious cases (e.g. not arguments to - * inline functions). Luckily, in 4.3 they added the "error" function - * attribute just for this type of case. Thus, we use a negative sized array - * (should always create an error on gcc versions older than 4.4) and then call - * an undefined function with the error attribute (should always create an - * error on gcc 4.3 and later). If for some reason, neither creates a - * compile-time error, we'll still have a link-time error, which is harder to - * track down. */ -#ifndef __OPTIMIZE__ -#define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)])) -#else #define BUILD_BUG_ON(condition) \ BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition) -#endif /** * BUILD_BUG - break compile if used. |