| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/arm26/lib/getuser.S |
| 3 | * |
| 4 | * Copyright (C) 2001 Russell King |
| 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 | * Idea from x86 version, (C) Copyright 1998 Linus Torvalds |
| 11 | * |
| 12 | * These functions have a non-standard call interface to make them more |
| 13 | * efficient, especially as they return an error value in addition to |
| 14 | * the "real" return value. |
| 15 | * |
| 16 | * __get_user_X |
| 17 | * |
| 18 | * Inputs: r0 contains the address |
| 19 | * Outputs: r0 is the error code |
| 20 | * r1, r2 contains the zero-extended value |
| 21 | * lr corrupted |
| 22 | * |
| 23 | * No other registers must be altered. (see include/asm-arm/uaccess.h |
| 24 | * for specific ASM register usage). |
| 25 | * |
| 26 | * Note that ADDR_LIMIT is either 0 or 0xc0000000. |
| 27 | * Note also that it is intended that __get_user_bad is not global. |
| 28 | */ |
| 29 | #include <asm/asm_offsets.h> |
| 30 | #include <asm/thread_info.h> |
| 31 | #include <asm/errno.h> |
| 32 | |
| 33 | .global __get_user_1 |
| 34 | __get_user_1: |
| 35 | bic r1, sp, #0x1f00 |
| 36 | bic r1, r1, #0x00ff |
| 37 | str lr, [sp, #-4]! |
| 38 | ldr r1, [r1, #TI_ADDR_LIMIT] |
| 39 | sub r1, r1, #1 |
| 40 | cmp r0, r1 |
| 41 | bge __get_user_bad |
| 42 | cmp r0, #0x02000000 |
| 43 | 1: ldrlsbt r1, [r0] |
| 44 | ldrgeb r1, [r0] |
| 45 | mov r0, #0 |
| 46 | ldmfd sp!, {pc}^ |
| 47 | |
| 48 | .global __get_user_2 |
| 49 | __get_user_2: |
| 50 | bic r2, sp, #0x1f00 |
| 51 | bic r2, r2, #0x00ff |
| 52 | str lr, [sp, #-4]! |
| 53 | ldr r2, [r2, #TI_ADDR_LIMIT] |
| 54 | sub r2, r2, #2 |
| 55 | cmp r0, r2 |
| 56 | bge __get_user_bad |
| 57 | cmp r0, #0x02000000 |
| 58 | 2: ldrlsbt r1, [r0], #1 |
| 59 | 3: ldrlsbt r2, [r0] |
| 60 | ldrgeb r1, [r0], #1 |
| 61 | ldrgeb r2, [r0] |
| 62 | orr r1, r1, r2, lsl #8 |
| 63 | mov r0, #0 |
| 64 | ldmfd sp!, {pc}^ |
| 65 | |
| 66 | .global __get_user_4 |
| 67 | __get_user_4: |
| 68 | bic r1, sp, #0x1f00 |
| 69 | bic r1, r1, #0x00ff |
| 70 | str lr, [sp, #-4]! |
| 71 | ldr r1, [r1, #TI_ADDR_LIMIT] |
| 72 | sub r1, r1, #4 |
| 73 | cmp r0, r1 |
| 74 | bge __get_user_bad |
| 75 | cmp r0, #0x02000000 |
| 76 | 4: ldrlst r1, [r0] |
| 77 | ldrge r1, [r0] |
| 78 | mov r0, #0 |
| 79 | ldmfd sp!, {pc}^ |
| 80 | |
| 81 | .global __get_user_8 |
| 82 | __get_user_8: |
| 83 | bic r2, sp, #0x1f00 |
| 84 | bic r2, r2, #0x00ff |
| 85 | str lr, [sp, #-4]! |
| 86 | ldr r2, [r2, #TI_ADDR_LIMIT] |
| 87 | sub r2, r2, #8 |
| 88 | cmp r0, r2 |
| 89 | bge __get_user_bad_8 |
| 90 | cmp r0, #0x02000000 |
| 91 | 5: ldrlst r1, [r0], #4 |
| 92 | 6: ldrlst r2, [r0] |
| 93 | ldrge r1, [r0], #4 |
| 94 | ldrge r2, [r0] |
| 95 | mov r0, #0 |
| 96 | ldmfd sp!, {pc}^ |
| 97 | |
| 98 | __get_user_bad_8: |
| 99 | mov r2, #0 |
| 100 | __get_user_bad: |
| 101 | mov r1, #0 |
| 102 | mov r0, #-EFAULT |
| 103 | ldmfd sp!, {pc}^ |
| 104 | |
| 105 | .section __ex_table, "a" |
| 106 | .long 1b, __get_user_bad |
| 107 | .long 2b, __get_user_bad |
| 108 | .long 3b, __get_user_bad |
| 109 | .long 4b, __get_user_bad |
| 110 | .long 5b, __get_user_bad_8 |
| 111 | .long 6b, __get_user_bad_8 |
| 112 | .previous |