| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * __get_user functions. |
| 3 | * |
| 4 | * (C) Copyright 1998 Linus Torvalds |
| 5 | * |
| 6 | * These functions have a non-standard call interface |
| 7 | * to make them more efficient, especially as they |
| 8 | * return an error value in addition to the "real" |
| 9 | * return value. |
| 10 | */ |
| 11 | #include <asm/thread_info.h> |
| 12 | |
| 13 | |
| 14 | /* |
| 15 | * __get_user_X |
| 16 | * |
| 17 | * Inputs: %eax contains the address |
| 18 | * |
| 19 | * Outputs: %eax is error code (0 or -EFAULT) |
| 20 | * %edx contains zero-extended value |
| 21 | * |
| 22 | * These functions should not modify any other registers, |
| 23 | * as they get called from within inline assembly. |
| 24 | */ |
| 25 | |
| 26 | .text |
| 27 | .align 4 |
| 28 | .globl __get_user_1 |
| 29 | __get_user_1: |
| 30 | GET_THREAD_INFO(%edx) |
| 31 | cmpl TI_addr_limit(%edx),%eax |
| 32 | jae bad_get_user |
| 33 | 1: movzbl (%eax),%edx |
| 34 | xorl %eax,%eax |
| 35 | ret |
| 36 | |
| 37 | .align 4 |
| 38 | .globl __get_user_2 |
| 39 | __get_user_2: |
| 40 | addl $1,%eax |
| 41 | jc bad_get_user |
| 42 | GET_THREAD_INFO(%edx) |
| 43 | cmpl TI_addr_limit(%edx),%eax |
| 44 | jae bad_get_user |
| 45 | 2: movzwl -1(%eax),%edx |
| 46 | xorl %eax,%eax |
| 47 | ret |
| 48 | |
| 49 | .align 4 |
| 50 | .globl __get_user_4 |
| 51 | __get_user_4: |
| 52 | addl $3,%eax |
| 53 | jc bad_get_user |
| 54 | GET_THREAD_INFO(%edx) |
| 55 | cmpl TI_addr_limit(%edx),%eax |
| 56 | jae bad_get_user |
| 57 | 3: movl -3(%eax),%edx |
| 58 | xorl %eax,%eax |
| 59 | ret |
| 60 | |
| 61 | bad_get_user: |
| 62 | xorl %edx,%edx |
| 63 | movl $-14,%eax |
| 64 | ret |
| 65 | |
| 66 | .section __ex_table,"a" |
| 67 | .long 1b,bad_get_user |
| 68 | .long 2b,bad_get_user |
| 69 | .long 3b,bad_get_user |
| 70 | .previous |