linux-stable/arch/x86/lib/string_32.c
Paul Gortmaker e683014c21 x86/lib: Audit and remove any unnecessary uses of module.h
Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends.  That changed
when we forked out support for the latter into the export.h file.

This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig.  The advantage
in doing so is that module.h itself sources about 15 other headers;
adding significantly to what we feed cpp, and it can obscure what
headers we are effectively using.

Since module.h was the source for init.h (for __init) and for
export.h (for EXPORT_SYMBOL) we consider each obj-y/bool instance
for the presence of either and replace as needed.  Build testing
revealed a couple implicit header usage issues that were fixed.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160714001901.31603-5-paul.gortmaker@windriver.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-14 15:06:58 +02:00

235 lines
4.6 KiB
C

/*
* Most of the string-functions are rather heavily hand-optimized,
* see especially strsep,strstr,str[c]spn. They should work, but are not
* very easy to understand. Everything is done entirely within the register
* set, making the functions fast and clean. String instructions have been
* used through-out, making for "slightly" unclear code :-)
*
* AK: On P4 and K7 using non string instruction implementations might be faster
* for large memory blocks. But most of them are unlikely to be used on large
* strings.
*/
#include <linux/string.h>
#include <linux/export.h>
#ifdef __HAVE_ARCH_STRCPY
char *strcpy(char *dest, const char *src)
{
int d0, d1, d2;
asm volatile("1:\tlodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b"
: "=&S" (d0), "=&D" (d1), "=&a" (d2)
: "0" (src), "1" (dest) : "memory");
return dest;
}
EXPORT_SYMBOL(strcpy);
#endif
#ifdef __HAVE_ARCH_STRNCPY
char *strncpy(char *dest, const char *src, size_t count)
{
int d0, d1, d2, d3;
asm volatile("1:\tdecl %2\n\t"
"js 2f\n\t"
"lodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n\t"
"rep\n\t"
"stosb\n"
"2:"
: "=&S" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3)
: "0" (src), "1" (dest), "2" (count) : "memory");
return dest;
}
EXPORT_SYMBOL(strncpy);
#endif
#ifdef __HAVE_ARCH_STRCAT
char *strcat(char *dest, const char *src)
{
int d0, d1, d2, d3;
asm volatile("repne\n\t"
"scasb\n\t"
"decl %1\n"
"1:\tlodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b"
: "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
: "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu) : "memory");
return dest;
}
EXPORT_SYMBOL(strcat);
#endif
#ifdef __HAVE_ARCH_STRNCAT
char *strncat(char *dest, const char *src, size_t count)
{
int d0, d1, d2, d3;
asm volatile("repne\n\t"
"scasb\n\t"
"decl %1\n\t"
"movl %8,%3\n"
"1:\tdecl %3\n\t"
"js 2f\n\t"
"lodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n"
"2:\txorl %2,%2\n\t"
"stosb"
: "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
: "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu), "g" (count)
: "memory");
return dest;
}
EXPORT_SYMBOL(strncat);
#endif
#ifdef __HAVE_ARCH_STRCMP
int strcmp(const char *cs, const char *ct)
{
int d0, d1;
int res;
asm volatile("1:\tlodsb\n\t"
"scasb\n\t"
"jne 2f\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n\t"
"xorl %%eax,%%eax\n\t"
"jmp 3f\n"
"2:\tsbbl %%eax,%%eax\n\t"
"orb $1,%%al\n"
"3:"
: "=a" (res), "=&S" (d0), "=&D" (d1)
: "1" (cs), "2" (ct)
: "memory");
return res;
}
EXPORT_SYMBOL(strcmp);
#endif
#ifdef __HAVE_ARCH_STRNCMP
int strncmp(const char *cs, const char *ct, size_t count)
{
int res;
int d0, d1, d2;
asm volatile("1:\tdecl %3\n\t"
"js 2f\n\t"
"lodsb\n\t"
"scasb\n\t"
"jne 3f\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n"
"2:\txorl %%eax,%%eax\n\t"
"jmp 4f\n"
"3:\tsbbl %%eax,%%eax\n\t"
"orb $1,%%al\n"
"4:"
: "=a" (res), "=&S" (d0), "=&D" (d1), "=&c" (d2)
: "1" (cs), "2" (ct), "3" (count)
: "memory");
return res;
}
EXPORT_SYMBOL(strncmp);
#endif
#ifdef __HAVE_ARCH_STRCHR
char *strchr(const char *s, int c)
{
int d0;
char *res;
asm volatile("movb %%al,%%ah\n"
"1:\tlodsb\n\t"
"cmpb %%ah,%%al\n\t"
"je 2f\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n\t"
"movl $1,%1\n"
"2:\tmovl %1,%0\n\t"
"decl %0"
: "=a" (res), "=&S" (d0)
: "1" (s), "0" (c)
: "memory");
return res;
}
EXPORT_SYMBOL(strchr);
#endif
#ifdef __HAVE_ARCH_STRLEN
size_t strlen(const char *s)
{
int d0;
size_t res;
asm volatile("repne\n\t"
"scasb"
: "=c" (res), "=&D" (d0)
: "1" (s), "a" (0), "0" (0xffffffffu)
: "memory");
return ~res - 1;
}
EXPORT_SYMBOL(strlen);
#endif
#ifdef __HAVE_ARCH_MEMCHR
void *memchr(const void *cs, int c, size_t count)
{
int d0;
void *res;
if (!count)
return NULL;
asm volatile("repne\n\t"
"scasb\n\t"
"je 1f\n\t"
"movl $1,%0\n"
"1:\tdecl %0"
: "=D" (res), "=&c" (d0)
: "a" (c), "0" (cs), "1" (count)
: "memory");
return res;
}
EXPORT_SYMBOL(memchr);
#endif
#ifdef __HAVE_ARCH_MEMSCAN
void *memscan(void *addr, int c, size_t size)
{
if (!size)
return addr;
asm volatile("repnz; scasb\n\t"
"jnz 1f\n\t"
"dec %%edi\n"
"1:"
: "=D" (addr), "=c" (size)
: "0" (addr), "1" (size), "a" (c)
: "memory");
return addr;
}
EXPORT_SYMBOL(memscan);
#endif
#ifdef __HAVE_ARCH_STRNLEN
size_t strnlen(const char *s, size_t count)
{
int d0;
int res;
asm volatile("movl %2,%0\n\t"
"jmp 2f\n"
"1:\tcmpb $0,(%0)\n\t"
"je 3f\n\t"
"incl %0\n"
"2:\tdecl %1\n\t"
"cmpl $-1,%1\n\t"
"jne 1b\n"
"3:\tsubl %2,%0"
: "=a" (res), "=&d" (d0)
: "c" (s), "1" (count)
: "memory");
return res;
}
EXPORT_SYMBOL(strnlen);
#endif