projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * __get_user functions. | |
| 3 | * | |
| 4 | * (C) Copyright 1998 Linus Torvalds | |
| 5 | * (C) Copyright 2005 Andi Kleen | |
| 6 | * | |
| 7 | * These functions have a non-standard call interface | |
| 8 | * to make them more efficient, especially as they | |
| 9 | * return an error value in addition to the "real" | |
| 10 | * return value. | |
| 11 | */ | |
| 12 | ||
| 13 | /* | |
| 14 | * __get_user_X | |
| 15 | * | |
| 16 | * Inputs: %rcx contains the address. | |
| 17 | * The register is modified, but all changes are undone | |
| 18 | * before returning because the C code doesn't know about it. | |
| 19 | * | |
| 20 | * Outputs: %rax is error code (0 or -EFAULT) | |
| 21 | * %rdx contains zero-extended value | |
| 22 | * | |
| 23 | * %r8 is destroyed. | |
| 24 | * | |
| 25 | * These functions should not modify any other registers, | |
| 26 | * as they get called from within inline assembly. | |
| 27 | */ | |
| 28 | ||
| 29 | #include <linux/linkage.h> | |
| 30 | #include <asm/page.h> | |
| 31 | #include <asm/errno.h> | |
| e2d5df93 | 32 | #include <asm/asm-offsets.h> |
| 1da177e4 LT |
33 | #include <asm/thread_info.h> |
| 34 | ||
| 35 | .text | |
| 36 | .p2align 4 | |
| 37 | .globl __get_user_1 | |
| 38 | __get_user_1: | |
| 39 | GET_THREAD_INFO(%r8) | |
| 40 | cmpq threadinfo_addr_limit(%r8),%rcx | |
| 41 | jae bad_get_user | |
| 42 | 1: movzb (%rcx),%edx | |
| 43 | xorl %eax,%eax | |
| 44 | ret | |
| 45 | ||
| 46 | .p2align 4 | |
| 47 | .globl __get_user_2 | |
| 48 | __get_user_2: | |
| 49 | GET_THREAD_INFO(%r8) | |
| 50 | addq $1,%rcx | |
| 51 | jc 20f | |
| 52 | cmpq threadinfo_addr_limit(%r8),%rcx | |
| 53 | jae 20f | |
| 54 | decq %rcx | |
| 55 | 2: movzwl (%rcx),%edx | |
| 56 | xorl %eax,%eax | |
| 57 | ret | |
| 58 | 20: decq %rcx | |
| 59 | jmp bad_get_user | |
| 60 | ||
| 61 | .p2align 4 | |
| 62 | .globl __get_user_4 | |
| 63 | __get_user_4: | |
| 64 | GET_THREAD_INFO(%r8) | |
| 65 | addq $3,%rcx | |
| 66 | jc 30f | |
| 67 | cmpq threadinfo_addr_limit(%r8),%rcx | |
| 68 | jae 30f | |
| 69 | subq $3,%rcx | |
| 70 | 3: movl (%rcx),%edx | |
| 71 | xorl %eax,%eax | |
| 72 | ret | |
| 73 | 30: subq $3,%rcx | |
| 74 | jmp bad_get_user | |
| 75 | ||
| 76 | .p2align 4 | |
| 77 | .globl __get_user_8 | |
| 78 | __get_user_8: | |
| 79 | GET_THREAD_INFO(%r8) | |
| 80 | addq $7,%rcx | |
| 3a6fd752 | 81 | jc 40f |
| 1da177e4 | 82 | cmpq threadinfo_addr_limit(%r8),%rcx |
| 3a6fd752 | 83 | jae 40f |
| 1da177e4 LT |
84 | subq $7,%rcx |
| 85 | 4: movq (%rcx),%rdx | |
| 86 | xorl %eax,%eax | |
| 87 | ret | |
| 88 | 40: subq $7,%rcx | |
| 89 | jmp bad_get_user | |
| 90 | ||
| 91 | bad_get_user: | |
| 92 | xorl %edx,%edx | |
| 93 | movq $(-EFAULT),%rax | |
| 94 | ret | |
| 95 | ||
| 96 | .section __ex_table,"a" | |
| 97 | .quad 1b,bad_get_user | |
| 98 | .quad 2b,bad_get_user | |
| 99 | .quad 3b,bad_get_user | |
| 100 | .quad 4b,bad_get_user | |
| 101 | .previous |