mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-24 14:37:48 +07:00
85 lines
2.0 KiB
C
85 lines
2.0 KiB
C
/*
|
|
* User address space access functions.
|
|
*
|
|
* Copyright 1997 Andi Kleen <ak@muc.de>
|
|
* Copyright 1997 Linus Torvalds
|
|
* Copyright 2002 Andi Kleen <ak@suse.de>
|
|
*/
|
|
#include <linux/export.h>
|
|
#include <linux/uaccess.h>
|
|
|
|
/*
|
|
* Zero Userspace
|
|
*/
|
|
|
|
unsigned long __clear_user(void __user *addr, unsigned long size)
|
|
{
|
|
long __d0;
|
|
might_fault();
|
|
/* no memory constraint because it doesn't change any memory gcc knows
|
|
about */
|
|
stac();
|
|
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"
|
|
_ASM_EXTABLE(0b,3b)
|
|
_ASM_EXTABLE(1b,2b)
|
|
: [size8] "=&c"(size), [dst] "=&D" (__d0)
|
|
: [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr),
|
|
[zero] "r" (0UL), [eight] "r" (8UL));
|
|
clac();
|
|
return size;
|
|
}
|
|
EXPORT_SYMBOL(__clear_user);
|
|
|
|
unsigned long clear_user(void __user *to, unsigned long n)
|
|
{
|
|
if (access_ok(VERIFY_WRITE, to, n))
|
|
return __clear_user(to, n);
|
|
return n;
|
|
}
|
|
EXPORT_SYMBOL(clear_user);
|
|
|
|
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;
|
|
}
|
|
EXPORT_SYMBOL(copy_in_user);
|
|
|
|
/*
|
|
* Try to copy last bytes and clear the rest if needed.
|
|
* Since protection fault in copy_from/to_user is not a normal situation,
|
|
* it is not necessary to optimize tail handling.
|
|
*/
|
|
__visible unsigned long
|
|
copy_user_handle_tail(char *to, char *from, unsigned len)
|
|
{
|
|
for (; len; --len, to++) {
|
|
char c;
|
|
|
|
if (__get_user_nocheck(c, from++, sizeof(char)))
|
|
break;
|
|
if (__put_user_nocheck(c, to, sizeof(char)))
|
|
break;
|
|
}
|
|
clac();
|
|
return len;
|
|
}
|