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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/config.h>
#include <xen/lib.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"
".section __ex_table,\"a\"\n"
" "__FIXUP_ALIGN"\n"
" "__FIXUP_WORD" 4b,5b\n"
" "__FIXUP_WORD" 0b,3b\n"
" "__FIXUP_WORD" 1b,2b\n"
".previous"
: "=&c"(__n), "=&D" (__d0), "=&S" (__d1), "=r"(__d2)
: "3"(__n), "0"(__n), "1"(to), "2"(from)
: "memory");
return (unsigned)__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"
".section __ex_table,\"a\"\n"
" "__FIXUP_ALIGN"\n"
" "__FIXUP_WORD" 4b,5b\n"
" "__FIXUP_WORD" 0b,3b\n"
" "__FIXUP_WORD" 1b,6b\n"
".previous"
: "=&c"(__n), "=&D" (__d0), "=&S" (__d1), "=r"(__d2)
: "3"(__n), "0"(__n), "1"(to), "2"(from)
: "memory");
return (unsigned)__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;
}
/**
* 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;
}
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