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x86, boot: Move memcmp() into string.h and string.c

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Try to treat memcmp() in same way as memcpy() and memset(). Provide a
declaration in boot/string.h and by default user gets a memcmp() which
maps to builtin function.

Move optimized definition of memcmp() in boot/string.c. Now a user can
do #undef memcmp and link against string.c to use optimzied memcmp().

It also simplifies boot/compressed/string.c where we had to redefine
memcmp(). That extra definition is gone now.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/1395170800-11059-5-git-send-email-vgoyal@redhat.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Vivek Goyal 2014-03-18 15:26:39 -04:00 committed by H. Peter Anvin
parent 820e8feca0
commit fb4cac573e
4 changed files with 16 additions and 19 deletions
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8
arch/x86/boot/boot.h
View File

@ -177,14 +177,6 @@ static inline void wrgs32(u32 v, addr_t addr)
}
/* Note: these only return true/false, not a signed return value! */
static inline int memcmp(const void *s1, const void *s2, size_t len)
{
u8 diff;
asm("repe; cmpsb; setnz %0"
: "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
return diff;
}
static inline int memcmp_fs(const void *s1, addr_t s2, size_t len)
{
u8 diff;

11
arch/x86/boot/compressed/string.c
View File

@ -1,15 +1,4 @@
#include "misc.h"
/* Avoid intereference from any defines in string_32.h */
#undef memcmp
int memcmp(const void *s1, const void *s2, size_t len)
{
u8 diff;
asm("repe; cmpsb; setnz %0"
: "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
return diff;
}
#include "../string.c"
/* misc.h might pull in string_32.h which has a macro for memcpy. undef that */

14
arch/x86/boot/string.c
View File

@ -14,6 +14,20 @@
#include "boot.h"
/*
* This file gets included in compressed/string.c which might pull in
* string_32.h and which in turn maps memcmp to __builtin_memcmp(). Undo
* that first.
*/
#undef memcmp
int memcmp(const void *s1, const void *s2, size_t len)
{
u8 diff;
asm("repe; cmpsb; setnz %0"
: "=qm" (diff), "+D" (s1), "+S" (s2), "+c" (len));
return diff;
}
int strcmp(const char *str1, const char *str2)
{
const unsigned char *s1 = (const unsigned char *)str1;

2
arch/x86/boot/string.h
View File

@ -8,6 +8,7 @@
void *memcpy(void *dst, const void *src, size_t len);
void *memset(void *dst, int c, size_t len);
int memcmp(const void *s1, const void *s2, size_t len);
/*
* Access builtin version by default. If one needs to use optimized version,
@ -15,5 +16,6 @@ void *memset(void *dst, int c, size_t len);
*/
#define memcpy(d,s,l) __builtin_memcpy(d,s,l)
#define memset(d,c,l) __builtin_memset(d,c,l)
#define memcmp __builtin_memcmp
#endif /* BOOT_STRING_H */