/* | |
* __put_user functions. | |
* | |
* (C) Copyright 2005 Linus Torvalds | |
* | |
* 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> | |
/* | |
* __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 ; \ | |
pushl %ebx ; \ | |
CFI_ADJUST_CFA_OFFSET 4 ; \ | |
CFI_REL_OFFSET ebx, 0 ; \ | |
GET_THREAD_INFO(%ebx) | |
#define EXIT popl %ebx ; \ | |
CFI_ADJUST_CFA_OFFSET -4 ; \ | |
CFI_RESTORE ebx ; \ | |
ret ; \ | |
CFI_ENDPROC | |
.text | |
ENTRY(__put_user_1) | |
ENTER | |
cmpl TI_addr_limit(%ebx),%ecx | |
jae bad_put_user | |
1: movb %al,(%ecx) | |
xorl %eax,%eax | |
EXIT | |
ENDPROC(__put_user_1) | |
ENTRY(__put_user_2) | |
ENTER | |
movl TI_addr_limit(%ebx),%ebx | |
subl $1,%ebx | |
cmpl %ebx,%ecx | |
jae bad_put_user | |
2: movw %ax,(%ecx) | |
xorl %eax,%eax | |
EXIT | |
ENDPROC(__put_user_2) | |
ENTRY(__put_user_4) | |
ENTER | |
movl TI_addr_limit(%ebx),%ebx | |
subl $3,%ebx | |
cmpl %ebx,%ecx | |
jae bad_put_user | |
3: movl %eax,(%ecx) | |
xorl %eax,%eax | |
EXIT | |
ENDPROC(__put_user_4) | |
ENTRY(__put_user_8) | |
ENTER | |
movl TI_addr_limit(%ebx),%ebx | |
subl $7,%ebx | |
cmpl %ebx,%ecx | |
jae bad_put_user | |
4: movl %eax,(%ecx) | |
5: movl %edx,4(%ecx) | |
xorl %eax,%eax | |
EXIT | |
ENDPROC(__put_user_8) | |
bad_put_user: | |
CFI_STARTPROC simple | |
CFI_DEF_CFA esp, 2*4 | |
CFI_OFFSET eip, -1*4 | |
CFI_OFFSET ebx, -2*4 | |
movl $-14,%eax | |
EXIT | |
END(bad_put_user) | |
.section __ex_table,"a" | |
.long 1b,bad_put_user | |
.long 2b,bad_put_user | |
.long 3b,bad_put_user | |
.long 4b,bad_put_user | |
.long 5b,bad_put_user | |
.previous |