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/*
* User address space access functions.
*
* Copyright 1997 Andi Kleen <ak@muc.de>
* Copyright 1997 Linus Torvalds
* Copyright 2002 Andi Kleen <ak@suse.de>
*/
#include <xen/lib.h>
#include <xen/sched.h>
#include <asm/uaccess.h>
unsigned long __copy_to_user_ll(void __user *to, const void *from, unsigned n)
{
unsigned long __d0, __d1, __d2, __n = n;
asm volatile (
" cmp $"STR(2*BYTES_PER_LONG-1)",%0\n"
" jbe 1f\n"
" mov %1,%0\n"
" neg %0\n"
" and $"STR(BYTES_PER_LONG-1)",%0\n"
" sub %0,%3\n"
"4: rep movsb\n" /* make 'to' address aligned */
" mov %3,%0\n"
" shr $"STR(LONG_BYTEORDER)",%0\n"
" and $"STR(BYTES_PER_LONG-1)",%3\n"
" .align 2,0x90\n"
"0: rep movs"__OS"\n" /* as many words as possible... */
" mov %3,%0\n"
"1: rep movsb\n" /* ...remainder copied as bytes */
"2:\n"
".section .fixup,\"ax\"\n"
"5: add %3,%0\n"
" jmp 2b\n"
"3: lea 0(%3,%0,"STR(BYTES_PER_LONG)"),%0\n"
" jmp 2b\n"
".previous\n"
_ASM_EXTABLE(4b, 5b)
_ASM_EXTABLE(0b, 3b)
_ASM_EXTABLE(1b, 2b)
: "=&c" (__n), "=&D" (__d0), "=&S" (__d1), "=&r" (__d2)
: "0" (__n), "1" (to), "2" (from), "3" (__n)
: "memory" );
return __n;
}
unsigned long
__copy_from_user_ll(void *to, const void __user *from, unsigned n)
{
unsigned long __d0, __d1, __d2, __n = n;
asm volatile (
" cmp $"STR(2*BYTES_PER_LONG-1)",%0\n"
" jbe 1f\n"
" mov %1,%0\n"
" neg %0\n"
" and $"STR(BYTES_PER_LONG-1)",%0\n"
" sub %0,%3\n"
"4: rep; movsb\n" /* make 'to' address aligned */
" mov %3,%0\n"
" shr $"STR(LONG_BYTEORDER)",%0\n"
" and $"STR(BYTES_PER_LONG-1)",%3\n"
" .align 2,0x90\n"
"0: rep; movs"__OS"\n" /* as many words as possible... */
" mov %3,%0\n"
"1: rep; movsb\n" /* ...remainder copied as bytes */
"2:\n"
".section .fixup,\"ax\"\n"
"5: add %3,%0\n"
" jmp 6f\n"
"3: lea 0(%3,%0,"STR(BYTES_PER_LONG)"),%0\n"
"6: push %0\n"
" push %%"__OP"ax\n"
" xor %%eax,%%eax\n"
" rep; stosb\n"
" pop %%"__OP"ax\n"
" pop %0\n"
" jmp 2b\n"
".previous\n"
_ASM_EXTABLE(4b, 5b)
_ASM_EXTABLE(0b, 3b)
_ASM_EXTABLE(1b, 6b)
: "=&c" (__n), "=&D" (__d0), "=&S" (__d1), "=&r" (__d2)
: "0" (__n), "1" (to), "2" (from), "3" (__n)
: "memory" );
return __n;
}
/**
* copy_to_user: - Copy a block of data into user space.
* @to: Destination address, in user space.
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from kernel space to user space.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*/
unsigned long
copy_to_user(void __user *to, const void *from, unsigned n)
{
if ( access_ok(to, n) )
n = __copy_to_user(to, from, n);
return n;
}
#define __do_clear_user(addr,size) \
do { \
long __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" \
_ASM_EXTABLE(0b,3b) \
_ASM_EXTABLE(1b,2b) \
: "=&c"(size), "=&D" (__d0) \
: "r"(size & 3), "0"(size / 4), "1"((long)addr), "a"(0)); \
} while (0)
/**
* clear_user: - Zero a block of memory in user space.
* @to: Destination address, in user space.
* @n: Number of bytes to zero.
*
* Zero a block of memory in user space.
*
* Returns number of bytes that could not be cleared.
* On success, this will be zero.
*/
unsigned long
clear_user(void __user *to, unsigned n)
{
if ( access_ok(to, n) )
__do_clear_user(to, n);
return n;
}
/**
* copy_from_user: - Copy a block of data from user space.
* @to: Destination address, in kernel space.
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from user space to kernel space.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*
* If some data could not be copied, this function will pad the copied
* data to the requested size using zero bytes.
*/
unsigned long
copy_from_user(void *to, const void __user *from, unsigned n)
{
if ( access_ok(from, n) )
n = __copy_from_user(to, from, n);
else
memset(to, 0, n);
return n;
}
/*
* Local variables:
* mode: C
* c-file-style: "BSD"
* c-basic-offset: 4
* tab-width: 4
* indent-tabs-mode: nil
* End:
*/
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