Viewing file:  usercopy.c (3.8 KB) -rw-r--r--
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/*
* User address space access functions.
* The non inlined parts of asm-i386/uaccess.h are here.
*
* Copyright 1997 Andi Kleen <ak@muc.de>
* Copyright 1997 Linus Torvalds
*/
#include <linux/config.h>
#include <asm/uaccess.h>
#include <asm/mmx.h>
#ifdef CONFIG_X86_USE_3DNOW_AND_WORKS
unsigned long
__generic_copy_to_user(void *to, const void *from, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
{
if(n<512)
__copy_user(to,from,n);
else
mmx_copy_user(to,from,n);
}
return n;
}
unsigned long
__generic_copy_from_user(void *to, const void *from, unsigned long n)
{
if (access_ok(VERIFY_READ, from, n))
{
if(n<512)
__copy_user_zeroing(to,from,n);
else
mmx_copy_user_zeroing(to, from, n);
}
else
memset(to, 0, n);
return n;
}
#else
unsigned long
__generic_copy_to_user(void *to, const void *from, unsigned long n)
{
prefetch(from);
if (access_ok(VERIFY_WRITE, to, n))
__copy_user(to,from,n);
return n;
}
unsigned long
__generic_copy_from_user(void *to, const void *from, unsigned long n)
{
prefetchw(to);
if (access_ok(VERIFY_READ, from, n))
__copy_user_zeroing(to,from,n);
else
memset(to, 0, n);
return n;
}
#endif
/*
* Copy a null terminated string from userspace.
*/
#define __do_strncpy_from_user(dst,src,count,res) \
do { \
int __d0, __d1, __d2; \
__asm__ __volatile__( \
" testl %1,%1\n" \
" jz 2f\n" \
"0: lodsb\n" \
" stosb\n" \
" testb %%al,%%al\n" \
" jz 1f\n" \
" decl %1\n" \
" jnz 0b\n" \
"1: subl %1,%0\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: movl %5,%0\n" \
" jmp 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 4\n" \
" .long 0b,3b\n" \
".previous" \
: "=d"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1), \
"=&D" (__d2) \
: "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \
: "memory"); \
} while (0)
long
__strncpy_from_user(char *dst, const char *src, long count)
{
long res;
__do_strncpy_from_user(dst, src, count, res);
return res;
}
long
strncpy_from_user(char *dst, const char *src, long count)
{
long res = -EFAULT;
if (access_ok(VERIFY_READ, src, 1))
__do_strncpy_from_user(dst, src, count, res);
return res;
}
/*
* Zero Userspace
*/
#define __do_clear_user(addr,size) \
do { \
int __d0; \
__asm__ __volatile__( \
"0: rep; stosl\n" \
" movl %2,%0\n" \
"1: rep; stosb\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: lea 0(%2,%0,4),%0\n" \
" jmp 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 4\n" \
" .long 0b,3b\n" \
" .long 1b,2b\n" \
".previous" \
: "=&c"(size), "=&D" (__d0) \
: "r"(size & 3), "0"(size / 4), "1"(addr), "a"(0)); \
} while (0)
unsigned long
clear_user(void *to, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
__do_clear_user(to, n);
return n;
}
unsigned long
__clear_user(void *to, unsigned long n)
{
__do_clear_user(to, n);
return n;
}
/*
* Return the size of a string (including the ending 0)
*
* Return 0 on exception, a value greater than N if too long
*/
long strnlen_user(const char *s, long n)
{
unsigned long mask = -__addr_ok(s);
unsigned long res, tmp;
__asm__ __volatile__(
" testl %0, %0\n"
" jz 3f\n"
" andl %0,%%ecx\n"
"0: repne; scasb\n"
" setne %%al\n"
" subl %%ecx,%0\n"
" addl %0,%%eax\n"
"1:\n"
".section .fixup,\"ax\"\n"
"2: xorl %%eax,%%eax\n"
" jmp 1b\n"
"3: movb $1,%%al\n"
" jmp 1b\n"
".previous\n"
".section __ex_table,\"a\"\n"
" .align 4\n"
" .long 0b,2b\n"
".previous"
:"=r" (n), "=D" (s), "=a" (res), "=c" (tmp)
:"0" (n), "1" (s), "2" (0), "3" (mask)
:"cc");
return res & mask;
}
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