| Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copy to/from userspace with optional address space checking. |
| 3 | * |
| 4 | * Copyright 2004-2006 Atmel Corporation |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | */ |
| 10 | #include <asm/page.h> |
| 11 | #include <asm/thread_info.h> |
| 12 | #include <asm/asm.h> |
| 13 | |
| 14 | /* |
| 15 | * __kernel_size_t |
| 16 | * __copy_user(void *to, const void *from, __kernel_size_t n) |
| 17 | * |
| 18 | * Returns the number of bytes not copied. Might be off by |
| 19 | * max 3 bytes if we get a fault in the main loop. |
| 20 | * |
| 21 | * The address-space checking functions simply fall through to |
| 22 | * the non-checking version. |
| 23 | */ |
| 24 | .text |
| 25 | .align 1 |
| 26 | .global copy_from_user |
| 27 | .type copy_from_user, @function |
| 28 | copy_from_user: |
| 29 | branch_if_kernel r8, __copy_user |
| 30 | ret_if_privileged r8, r11, r10, r10 |
| 31 | rjmp __copy_user |
| 32 | .size copy_from_user, . - copy_from_user |
| 33 | |
| 34 | .global copy_to_user |
| 35 | .type copy_to_user, @function |
| 36 | copy_to_user: |
| 37 | branch_if_kernel r8, __copy_user |
| 38 | ret_if_privileged r8, r12, r10, r10 |
| 39 | .size copy_to_user, . - copy_to_user |
| 40 | |
| 41 | .global __copy_user |
| 42 | .type __copy_user, @function |
| 43 | __copy_user: |
| 44 | mov r9, r11 |
| 45 | andl r9, 3, COH |
| 46 | brne 6f |
| 47 | |
| 48 | /* At this point, from is word-aligned */ |
| 49 | 1: sub r10, 4 |
| 50 | brlt 3f |
| 51 | |
| 52 | 2: |
| 53 | 10: ld.w r8, r11++ |
| 54 | 11: st.w r12++, r8 |
| 55 | sub r10, 4 |
| 56 | brge 2b |
| 57 | |
| 58 | 3: sub r10, -4 |
| 59 | reteq 0 |
| 60 | |
| 61 | /* |
| 62 | * Handle unaligned count. Need to be careful with r10 here so |
| 63 | * that we return the correct value even if we get a fault |
| 64 | */ |
| 65 | 4: |
| 66 | 20: ld.ub r8, r11++ |
| 67 | 21: st.b r12++, r8 |
| 68 | sub r10, 1 |
| 69 | reteq 0 |
| 70 | 22: ld.ub r8, r11++ |
| 71 | 23: st.b r12++, r8 |
| 72 | sub r10, 1 |
| 73 | reteq 0 |
| 74 | 24: ld.ub r8, r11++ |
| 75 | 25: st.b r12++, r8 |
| 76 | retal 0 |
| 77 | |
| 78 | /* Handle unaligned from-pointer */ |
| 79 | 6: cp.w r10, 4 |
| 80 | brlt 4b |
| 81 | rsub r9, r9, 4 |
| 82 | |
| 83 | 30: ld.ub r8, r11++ |
| 84 | 31: st.b r12++, r8 |
| 85 | sub r10, 1 |
| 86 | sub r9, 1 |
| 87 | breq 1b |
| 88 | 32: ld.ub r8, r11++ |
| 89 | 33: st.b r12++, r8 |
| 90 | sub r10, 1 |
| 91 | sub r9, 1 |
| 92 | breq 1b |
| 93 | 34: ld.ub r8, r11++ |
| 94 | 35: st.b r12++, r8 |
| 95 | sub r10, 1 |
| 96 | rjmp 1b |
| 97 | .size __copy_user, . - __copy_user |
| 98 | |
| 99 | .section .fixup,"ax" |
| 100 | .align 1 |
| 101 | 19: sub r10, -4 |
| 102 | 29: retal r10 |
| 103 | |
| 104 | .section __ex_table,"a" |
| 105 | .align 2 |
| 106 | .long 10b, 19b |
| 107 | .long 11b, 19b |
| 108 | .long 20b, 29b |
| 109 | .long 21b, 29b |
| 110 | .long 22b, 29b |
| 111 | .long 23b, 29b |
| 112 | .long 24b, 29b |
| 113 | .long 25b, 29b |
| 114 | .long 30b, 29b |
| 115 | .long 31b, 29b |
| 116 | .long 32b, 29b |
| 117 | .long 33b, 29b |
| 118 | .long 34b, 29b |
| 119 | .long 35b, 29b |