Many calls to memcmp(), strncmp(), strncpy() and memchr() are done with constant size.
This patch gives GCC a chance to optimise out the NUL size verification. This is only done when CONFIG_FORTIFY_SOURCE is not set, because when CONFIG_FORTIFY_SOURCE is set, other inline versions of the functions are defined in linux/string.h and conflict with ours. Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr> --- arch/powerpc/include/asm/string.h | 45 +++++++++++++++++++++++++++++++--- arch/powerpc/kernel/prom_init_check.sh | 2 +- arch/powerpc/lib/memcmp_64.S | 8 ++++++ arch/powerpc/lib/string.S | 14 +++++++++++ arch/powerpc/lib/string_32.S | 8 ++++++ 5 files changed, 73 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/include/asm/string.h b/arch/powerpc/include/asm/string.h index 9b8cedf618f4..35f1aaad9b50 100644 --- a/arch/powerpc/include/asm/string.h +++ b/arch/powerpc/include/asm/string.h @@ -15,17 +15,56 @@ #define __HAVE_ARCH_MEMCPY_FLUSHCACHE extern char * strcpy(char *,const char *); -extern char * strncpy(char *,const char *, __kernel_size_t); extern __kernel_size_t strlen(const char *); extern int strcmp(const char *,const char *); -extern int strncmp(const char *, const char *, __kernel_size_t); extern char * strcat(char *, const char *); extern void * memset(void *,int,__kernel_size_t); extern void * memcpy(void *,const void *,__kernel_size_t); extern void * memmove(void *,const void *,__kernel_size_t); +extern void * memcpy_flushcache(void *,const void *,__kernel_size_t); + +#ifdef CONFIG_FORTIFY_SOURCE + +extern char * strncpy(char *,const char *, __kernel_size_t); +extern int strncmp(const char *, const char *, __kernel_size_t); 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); + +#else + +extern char *__strncpy(char *,const char *, __kernel_size_t); +extern int __strncmp(const char *, const char *, __kernel_size_t); +extern int __memcmp(const void *,const void *,__kernel_size_t); +extern void *__memchr(const void *,int,__kernel_size_t); + +static inline char *strncpy(char *p, const char *q, __kernel_size_t size) +{ + if (unlikely(!size)) + return p; + return __strncpy(p, q, size); +} + +static inline int strncmp(const char *p, const char *q, __kernel_size_t size) +{ + if (unlikely(!size)) + return 0; + return __strncmp(p, q, size); +} + +static inline int memcmp(const void *p,const void *q,__kernel_size_t size) +{ + if (unlikely(!size)) + return 0; + return __memcmp(p, q, size); +} + +static inline void *memchr(const void *p, int c, __kernel_size_t size) +{ + if (unlikely(!size)) + return NULL; + return __memchr(p, c, size); +} +#endif #ifdef CONFIG_PPC64 #define __HAVE_ARCH_MEMSET32 diff --git a/arch/powerpc/kernel/prom_init_check.sh b/arch/powerpc/kernel/prom_init_check.sh index acb6b9226352..2d87e5f9d87b 100644 --- a/arch/powerpc/kernel/prom_init_check.sh +++ b/arch/powerpc/kernel/prom_init_check.sh @@ -18,7 +18,7 @@ WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush _end enter_prom memcpy memset reloc_offset __secondary_hold -__secondary_hold_acknowledge __secondary_hold_spinloop __start +__secondary_hold_acknowledge __secondary_hold_spinloop __start __strncmp strcmp strcpy strlcpy strlen strncmp strstr kstrtobool logo_linux_clut224 reloc_got2 kernstart_addr memstart_addr linux_banner _stext __prom_init_toc_start __prom_init_toc_end btext_setup_display TOC." diff --git a/arch/powerpc/lib/memcmp_64.S b/arch/powerpc/lib/memcmp_64.S index d75d18b7bd55..9b28286b85cf 100644 --- a/arch/powerpc/lib/memcmp_64.S +++ b/arch/powerpc/lib/memcmp_64.S @@ -29,8 +29,14 @@ #define LD ldx #endif +#ifndef CONFIG_FORTIFY_SOURCE +#define memcmp __memcmp +#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 +45,9 @@ _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.S b/arch/powerpc/lib/string.S index 0ef189847337..2521c159e644 100644 --- a/arch/powerpc/lib/string.S +++ b/arch/powerpc/lib/string.S @@ -14,12 +14,20 @@ #include <asm/export.h> .text + +#ifndef CONFIG_FORTIFY_SOURCE +#define strncpy __strncpy +#define strncmp __strncmp +#define memchr __memchr +#endif /* This clears out any unused part of the destination buffer, just as the libc version does. -- paulus */ _GLOBAL(strncpy) +#ifdef CONFIG_FORTIFY_SOURCE PPC_LCMPI 0,r5,0 beqlr +#endif mtctr r5 addi r6,r3,-1 addi r4,r4,-1 @@ -40,8 +48,10 @@ _GLOBAL(strncpy) EXPORT_SYMBOL(strncpy) _GLOBAL(strncmp) +#ifdef CONFIG_FORTIFY_SOURCE PPC_LCMPI 0,r5,0 beq- 2f +#endif mtctr r5 addi r5,r3,-1 addi r4,r4,-1 @@ -55,13 +65,17 @@ _GLOBAL(strncmp) beqlr 1 bdnzt eq,1b blr +#ifdef CONFIG_FORTIFY_SOURCE 2: li r3,0 blr +#endif EXPORT_SYMBOL(strncmp) _GLOBAL(memchr) +#ifdef CONFIG_FORTIFY_SOURCE PPC_LCMPI 0,r5,0 beq- 2f +#endif mtctr r5 addi r3,r3,-1 #ifdef CONFIG_PPC64 diff --git a/arch/powerpc/lib/string_32.S b/arch/powerpc/lib/string_32.S index 5c0e77baa9c7..15f6fa175ec1 100644 --- a/arch/powerpc/lib/string_32.S +++ b/arch/powerpc/lib/string_32.S @@ -17,9 +17,15 @@ .text +#ifndef CONFIG_FORTIFY_SOURCE +#define memcmp __memcmp +#endif + _GLOBAL(memcmp) +#ifdef CONFIG_FORTIFY_SOURCE PPC_LCMPI 0,r5,0 beq- 2f +#endif srawi. r7, r5, 2 /* Divide len by 4 */ mr r6, r3 beq- 3f @@ -56,8 +62,10 @@ _GLOBAL(memcmp) lbzx r0, r4, r7 subf. r3, r0, r3 blr +#ifdef CONFIG_FORTIFY_SOURCE 2: li r3,0 blr +#endif EXPORT_SYMBOL(memcmp) CACHELINE_BYTES = L1_CACHE_BYTES -- 2.13.3