/*
* User address space access functions.
*
* Copyright 1997 Andi Kleen <ak@muc.de>
* Copyright 1997 Linus Torvalds
* Copyright 2002 Andi Kleen <ak@suse.de>
*/
#include <asm/uaccess.h>
/*
* Copy a null terminated string from userspace.
*/
#define __do_strncpy_from_user(dst,src,count,res) \
do { \
long __d0, __d1, __d2; \
might_sleep(); \
__asm__ __volatile__( \
" testq %1,%1\n" \
" jz 2f\n" \
"0: lodsb\n" \
" stosb\n" \
" testb %%al,%%al\n" \
" jz 1f\n" \
" decq %1\n" \
" jnz 0b\n" \
"1: subq %1,%0\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: movq %5,%0\n" \
" jmp 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 8\n" \
" .quad 0b,3b\n" \
".previous" \
: "=r"(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 __user *src, long count)
{
long res;
__do_strncpy_from_user(dst, src, count, res);
return res;
}
long
strncpy_from_user(char *dst, const char __user *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
*/
unsigned long __clear_user(void __user *addr, unsigned long size)
{
long __d0;
might_sleep();
/* no memory constraint because it doesn't change any memory gcc knows
about */
asm volatile(
" testq %[size8],%[size8]\n"
" jz 4f\n"
"0: movq %[zero],(%[dst])\n"
" addq %[eight],%[dst]\n"
" decl %%ecx ; jnz 0b\n"
"4: movq %[size1],%%rcx\n"
" testl %%ecx,%%ecx\n"
" jz 2f\n"
"1: movb %b[zero],(%[dst])\n"
" incq %[dst]\n"
" decl %%ecx ; jnz 1b\n"
"2:\n"
".section .fixup,\"ax\"\n"
"3: lea 0(%[size1],%[size8],8),%[size8]\n"
" jmp 2b\n"
".previous\n"
".section __ex_table,\"a\"\n"
" .align 8\n"
" .quad 0b,3b\n"
" .quad 1b,2b\n"
".previous"
: [size8] "=c"(size), [dst] "=&D" (__d0)
: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
[zero] "r" (0UL), [eight] "r" (8UL));
return size;
}
unsigned long clear_user(void __user *to, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
return __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 __user *s, long n)
{
long res = 0;
char c;
if (!access_ok(VERIFY_READ, s, n))
return 0;
while (1) {
if (res>n)
return n+1;
if (__get_user(c, s))
return 0;
if (!c)
return res+1;
res++;
s++;
}
}
long strlen_user(const char __user *s)
{
long res = 0;
char c;
for (;;) {
if (get_user(c, s))
return 0;
if (!c)
return res+1;
res++;
s++;
}
}
unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len)
{
if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) {
return copy_user_generic((__force void *)to, (__force void *)from, len);
}
return len;
}
