Messages in this thread Patch in this message | | | From | Andrey Ryabinin <> | Subject | [PATCH] compiler, READ_ONCE: Fix build failure with some older GCC | Date | Thu, 15 Oct 2015 13:19:51 +0300 |
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Some old versions of GCC doesn't handle __alias (or maybe a combination of 'static __always_inline __alias') right.
GCC creates outline and unused copy of __read_once_size_check() function in the object file which references memcpy and causes the build failure: arch/x86/entry/vdso/vclock_gettime.o: In function `__read_once_size_check': vclock_gettime.c:(.text+0x5f): undefined reference to `memcpy' arch/x86/entry/vdso/vgetcpu.o: In function `__read_once_size_check': vgetcpu.c:(.text+0x2f): undefined reference to `memcpy'
We could avoid using alias to work around this problem.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> --- include/linux/compiler.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index aa2ae4c..3436a4c 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -231,8 +231,11 @@ void __read_once_size_nocheck(const volatile void *p, void *res, int size) __READ_ONCE_SIZE; } #else -static __always_inline __alias(__read_once_size_check) -void __read_once_size_nocheck(const volatile void *p, void *res, int size); +static __always_inline +void __read_once_size_nocheck(const volatile void *p, void *res, int size) +{ + __READ_ONCE_SIZE; +} #endif static __always_inline void __write_once_size(volatile void *p, void *res, int size) -- 2.4.9
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