/* | |
* __get_user functions. | |
* | |
* (C) Copyright 1998 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 <asm/thread_info.h> | |
/* | |
* __get_user_X | |
* | |
* Inputs: %eax contains the address | |
* | |
* Outputs: %eax is error code (0 or -EFAULT) | |
* %edx contains zero-extended value | |
* | |
* These functions should not modify any other registers, | |
* as they get called from within inline assembly. | |
*/ | |
.text | |
.align 4 | |
.globl __get_user_1 | |
__get_user_1: | |
GET_THREAD_INFO(%edx) | |
cmpl TI_addr_limit(%edx),%eax | |
jae bad_get_user | |
1: movzbl (%eax),%edx | |
xorl %eax,%eax | |
ret | |
.align 4 | |
.globl __get_user_2 | |
__get_user_2: | |
addl $1,%eax | |
jc bad_get_user | |
GET_THREAD_INFO(%edx) | |
cmpl TI_addr_limit(%edx),%eax | |
jae bad_get_user | |
2: movzwl -1(%eax),%edx | |
xorl %eax,%eax | |
ret | |
.align 4 | |
.globl __get_user_4 | |
__get_user_4: | |
addl $3,%eax | |
jc bad_get_user | |
GET_THREAD_INFO(%edx) | |
cmpl TI_addr_limit(%edx),%eax | |
jae bad_get_user | |
3: movl -3(%eax),%edx | |
xorl %eax,%eax | |
ret | |
bad_get_user: | |
xorl %edx,%edx | |
movl $-14,%eax | |
ret | |
.section __ex_table,"a" | |
.long 1b,bad_get_user | |
.long 2b,bad_get_user | |
.long 3b,bad_get_user | |
.previous |