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authorMasahiro Yamada <yamada.masahiro@socionext.com>2019-01-03 15:26:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-01-04 13:13:45 -0800
commitc60d3b79423aab402085c30b33bfff5354a61d8b (patch)
treede72c302ae424ec617c5221306b637badd2656d2 /include
parent3fe5dbfef47e992b810cbe82af1df02d8255fb8c (diff)
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')
-rw-r--r--include/linux/build_bug.h14
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.