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Commit fb4cac57 authored by Vivek Goyal's avatar Vivek Goyal Committed by H. Peter Anvin
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x86, boot: Move memcmp() into string.h and string.c 



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: default avatarVivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/r/1395170800-11059-5-git-send-email-vgoyal@redhat.com


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 820e8fec

arch/x86/boot/boot.h

+0 −8
Original line number Diff line number Diff line
@@ -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;

arch/x86/boot/compressed/string.c

+0 −11
Original line number Diff line number Diff line 
#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 */

arch/x86/boot/string.c

+14 −0
Original line number Diff line number Diff line
@@ -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;

arch/x86/boot/string.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */