Messages in this thread Patch in this message | | | From | Christophe Leroy <> | Subject | [PATCH 2/7] powerpc/lib: inline memcmp() NUL size verification | Date | Tue, 17 Apr 2018 09:38:37 +0200 (CEST) |
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Many calls to memcmp() are done with constant size. This patch gives GCC a chance to optimise out the NULL size verification.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- arch/powerpc/include/asm/string.h | 10 ++++++++++ arch/powerpc/lib/memcmp_64.S | 4 ++++ arch/powerpc/lib/string_32.S | 4 ++++ 3 files changed, 18 insertions(+)
diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h index 9b8cedf618f4..cf6f495134c3 100644 --- a/arch/powerpc/include/asm/string.h +++ b/arch/powerpc/include/asm/string.h @@ -27,6 +27,16 @@ extern int memcmp(const void *,const void *,__kernel_size_t); extern void * memchr(const void *,int,__kernel_size_t); extern void * memcpy_flushcache(void *,const void *,__kernel_size_t); +#ifndef CONFIG_FORTIFY_SOURCE +static inline int __memcmp(const void *p,const void *q,__kernel_size_t size) +{ + if (unlikely(!size)) + return 0; + return memcmp(p, q, size); +} +#define memcmp __memcmp +#endif + #ifdef CONFIG_PPC64 #define __HAVE_ARCH_MEMSET32 #define __HAVE_ARCH_MEMSET64 diff --git a/arch/powerpc/lib/memcmp_64.S b/arch/powerpc/lib/memcmp_64.S index d75d18b7bd55..f6822fabf254 100644 --- a/arch/powerpc/lib/memcmp_64.S +++ b/arch/powerpc/lib/memcmp_64.S @@ -30,7 +30,9 @@ #endif _GLOBAL(memcmp) +#ifdef CONFIG_FORTIFY_SOURCE cmpdi cr1,r5,0 +#endif /* Use the short loop if both strings are not 8B aligned */ or r6,r3,r4 @@ -39,7 +41,9 @@ _GLOBAL(memcmp) /* Use the short loop if length is less than 32B */ cmpdi cr6,r5,31 +#ifdef CONFIG_FORTIFY_SOURCE beq cr1,.Lzero +#endif bne .Lshort bgt cr6,.Llong diff --git a/arch/powerpc/lib/string_32.S b/arch/powerpc/lib/string_32.S index 2519f8bd09e3..94e9c9bc31c3 100644 --- a/arch/powerpc/lib/string_32.S +++ b/arch/powerpc/lib/string_32.S @@ -15,8 +15,10 @@ .text _GLOBAL(memcmp) +#ifdef CONFIG_FORTIFY_SOURCE PPC_LCMPI 0,r5,0 beq- 2f +#endif mtctr r5 addi r6,r3,-1 addi r4,r4,-1 @@ -25,8 +27,10 @@ _GLOBAL(memcmp) subf. r3,r0,r3 bdnzt 2,1b blr +#ifdef CONFIG_FORTIFY_SOURCE 2: li r3,0 blr +#endif EXPORT_SYMBOL(memcmp) _GLOBAL(__clear_user) -- 2.13.3
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