/* | |
* __put_user functions. | |
* | |
* (C) Copyright 2005 Linus Torvalds | |
* (C) Copyright 2005 Andi Kleen | |
* (C) Copyright 2008 Glauber Costa | |
* | |
* These functions have a non-standard call interface | |
* to make them more efficient, especially as they | |
* return an error value in addition to the "real" | |
* return value. | |
*/ | |
#include <linux/linkage.h> | |
#include <asm/dwarf2.h> | |
#include <asm/thread_info.h> | |
#include <asm/errno.h> | |
#include <asm/asm.h> | |
/* | |
* __put_user_X | |
* | |
* Inputs: %eax[:%edx] contains the data | |
* %ecx contains the address | |
* | |
* Outputs: %eax is error code (0 or -EFAULT) | |
* | |
* These functions should not modify any other registers, | |
* as they get called from within inline assembly. | |
*/ | |
#define ENTER CFI_STARTPROC ; \ | |
GET_THREAD_INFO(%_ASM_BX) | |
#define EXIT ret ; \ | |
CFI_ENDPROC | |
.text | |
ENTRY(__put_user_1) | |
ENTER | |
cmp TI_addr_limit(%_ASM_BX),%_ASM_CX | |
jae bad_put_user | |
1: movb %al,(%_ASM_CX) | |
xor %eax,%eax | |
EXIT | |
ENDPROC(__put_user_1) | |
ENTRY(__put_user_2) | |
ENTER | |
mov TI_addr_limit(%_ASM_BX),%_ASM_BX | |
sub $1,%_ASM_BX | |
cmp %_ASM_BX,%_ASM_CX | |
jae bad_put_user | |
2: movw %ax,(%_ASM_CX) | |
xor %eax,%eax | |
EXIT | |
ENDPROC(__put_user_2) | |
ENTRY(__put_user_4) | |
ENTER | |
mov TI_addr_limit(%_ASM_BX),%_ASM_BX | |
sub $3,%_ASM_BX | |
cmp %_ASM_BX,%_ASM_CX | |
jae bad_put_user | |
3: movl %eax,(%_ASM_CX) | |
xor %eax,%eax | |
EXIT | |
ENDPROC(__put_user_4) | |
ENTRY(__put_user_8) | |
ENTER | |
mov TI_addr_limit(%_ASM_BX),%_ASM_BX | |
sub $7,%_ASM_BX | |
cmp %_ASM_BX,%_ASM_CX | |
jae bad_put_user | |
4: mov %_ASM_AX,(%_ASM_CX) | |
#ifdef CONFIG_X86_32 | |
5: movl %edx,4(%_ASM_CX) | |
#endif | |
xor %eax,%eax | |
EXIT | |
ENDPROC(__put_user_8) | |
bad_put_user: | |
CFI_STARTPROC | |
movl $-EFAULT,%eax | |
EXIT | |
END(bad_put_user) | |
.section __ex_table,"a" | |
_ASM_PTR 1b,bad_put_user | |
_ASM_PTR 2b,bad_put_user | |
_ASM_PTR 3b,bad_put_user | |
_ASM_PTR 4b,bad_put_user | |
#ifdef CONFIG_X86_32 | |
_ASM_PTR 5b,bad_put_user | |
#endif | |
.previous |