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Subject[patch 1/1] x86_64: make string func definition work as intended
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From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
CC: Andi Kleen <ak@suse.de>

In include/asm-x86_64/string.h there are such comments:

/* Use C out of line version for memcmp */
#define memcmp __builtin_memcmp
int memcmp(const void * cs,const void * ct,size_t count);
This would mean that if the compiler does not decide to use __builtin_memcmp,
it emits a call to memcmp to be satisfied by the C out-of-line version in
lib/string.c. What happens is that after preprocessing, in lib/string.i you
may find the definition of "__builtin_strcmp".

Actually, by accident, in the object you will find the definition of
strcmp and such (maybe a trick intended to redirect calls to __builtin_memcmp
to the default memcmp when the definition is not expanded); however, this
particular case is not a documented feature as far as I can see.

Also, the EXPORT_SYMBOL does not work, so it's duplicated in the arch.

I simply added some #undef to lib/string.c and removed the (now duplicated)
exports in x86-64 and UML/x86_64 subarchs (the second ones are introduced by
another patch I just posted for -mm).

I agree this can be a bit kludgy, so if you want add another solution.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
---
linux-2.6.12-paolo/arch/um/sys-x86_64/ksyms.c | 3 ---
linux-2.6.12-paolo/arch/x86_64/kernel/x8664_ksyms.c | 13 -------------
linux-2.6.12-paolo/lib/string.c | 4 ++++
3 files changed, 4 insertions(+), 16 deletions(-)
diff -puN include/asm-x86_64/string.h~x86_64-string-func include/asm-x86_64/string.h
diff -puN lib/string.c~x86_64-string-func lib/string.c
--- linux-2.6.12/lib/string.c~x86_64-string-func 2005-05-01 20:45:29.000000000 +0200
+++ linux-2.6.12-paolo/lib/string.c 2005-05-01 20:45:29.000000000 +0200
@@ -65,6 +65,7 @@ EXPORT_SYMBOL(strnicmp);
* @dest: Where to copy the string to
* @src: Where to copy the string from
*/
+#undef strcpy
char * strcpy(char * dest,const char *src)
{
char *tmp = dest;
@@ -132,6 +133,7 @@ EXPORT_SYMBOL(strlcpy);
* @dest: The string to be appended to
* @src: The string to append to it
*/
+#undef strcat
char * strcat(char * dest, const char * src)
{
char *tmp = dest;
@@ -209,6 +211,7 @@ EXPORT_SYMBOL(strlcat);
* @cs: One string
* @ct: Another string
*/
+#undef strcmp
int strcmp(const char * cs,const char * ct)
{
register signed char __res;
@@ -514,6 +517,7 @@ EXPORT_SYMBOL(memmove);
* @ct: Another area of memory
* @count: The size of the area.
*/
+#undef memcmp
int memcmp(const void * cs,const void * ct,size_t count)
{
const unsigned char *su1, *su2;
diff -puN arch/x86_64/kernel/x8664_ksyms.c~x86_64-string-func arch/x86_64/kernel/x8664_ksyms.c
--- linux-2.6.12/arch/x86_64/kernel/x8664_ksyms.c~x86_64-string-func 2005-05-01 20:45:29.000000000 +0200
+++ linux-2.6.12-paolo/arch/x86_64/kernel/x8664_ksyms.c 2005-05-01 20:45:29.000000000 +0200
@@ -139,35 +139,23 @@ EXPORT_SYMBOL_GPL(unset_nmi_callback);
#undef memmove
#undef memchr
#undef strlen
-#undef strcpy
#undef strncmp
#undef strncpy
#undef strchr
-#undef strcmp
-#undef strcpy
-#undef strcat
-#undef memcmp

extern void * memset(void *,int,__kernel_size_t);
extern size_t strlen(const char *);
extern void * memmove(void * dest,const void *src,size_t count);
-extern char * strcpy(char * dest,const char *src);
-extern int strcmp(const char * cs,const char * ct);
extern void *memchr(const void *s, int c, size_t n);
extern void * memcpy(void *,const void *,__kernel_size_t);
extern void * __memcpy(void *,const void *,__kernel_size_t);
-extern char * strcat(char *, const char *);
-extern int memcmp(const void * cs,const void * ct,size_t count);

EXPORT_SYMBOL(memset);
EXPORT_SYMBOL(strlen);
EXPORT_SYMBOL(memmove);
-EXPORT_SYMBOL(strcpy);
EXPORT_SYMBOL(strncmp);
EXPORT_SYMBOL(strncpy);
EXPORT_SYMBOL(strchr);
-EXPORT_SYMBOL(strcmp);
-EXPORT_SYMBOL(strcat);
EXPORT_SYMBOL(strncat);
EXPORT_SYMBOL(memchr);
EXPORT_SYMBOL(strrchr);
@@ -175,7 +163,6 @@ EXPORT_SYMBOL(strnlen);
EXPORT_SYMBOL(memscan);
EXPORT_SYMBOL(memcpy);
EXPORT_SYMBOL(__memcpy);
-EXPORT_SYMBOL(memcmp);

#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM
/* prototypes are wrong, these are assembly with custom calling functions */
diff -puN arch/um/sys-x86_64/ksyms.c~x86_64-string-func arch/um/sys-x86_64/ksyms.c
--- linux-2.6.12/arch/um/sys-x86_64/ksyms.c~x86_64-string-func 2005-05-01 20:45:29.000000000 +0200
+++ linux-2.6.12-paolo/arch/um/sys-x86_64/ksyms.c 2005-05-01 20:45:29.000000000 +0200
@@ -14,9 +14,6 @@ EXPORT_SYMBOL(__up_wakeup);

/*XXX: we need them because they would be exported by x86_64 */
EXPORT_SYMBOL(__memcpy);
-EXPORT_SYMBOL(strcmp);
-EXPORT_SYMBOL(strcat);
-EXPORT_SYMBOL(strcpy);

/* Networking helper routines. */
/*EXPORT_SYMBOL(csum_partial_copy_from);
_
-
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