| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/arch/arm/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 | * r2, r3 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/constants.h> |
| 30 | #include <asm/thread_info.h> |
| 31 | #include <asm/errno.h> |
| 32 | |
| 33 | .global __get_user_1 |
| 34 | __get_user_1: |
| 35 | 1: ldrbt r2, [r0] |
| 36 | mov r0, #0 |
| 37 | mov pc, lr |
| 38 | |
| 39 | .global __get_user_2 |
| 40 | __get_user_2: |
| 41 | 2: ldrbt r2, [r0], #1 |
| 42 | 3: ldrbt r3, [r0] |
| 43 | #ifndef __ARMEB__ |
| 44 | orr r2, r2, r3, lsl #8 |
| 45 | #else |
| 46 | orr r2, r3, r2, lsl #8 |
| 47 | #endif |
| 48 | mov r0, #0 |
| 49 | mov pc, lr |
| 50 | |
| 51 | .global __get_user_4 |
| 52 | __get_user_4: |
| 53 | 4: ldrt r2, [r0] |
| 54 | mov r0, #0 |
| 55 | mov pc, lr |
| 56 | |
| 57 | .global __get_user_8 |
| 58 | __get_user_8: |
| 59 | 5: ldrt r2, [r0], #4 |
| 60 | 6: ldrt r3, [r0] |
| 61 | mov r0, #0 |
| 62 | mov pc, lr |
| 63 | |
| 64 | __get_user_bad_8: |
| 65 | mov r3, #0 |
| 66 | __get_user_bad: |
| 67 | mov r2, #0 |
| 68 | mov r0, #-EFAULT |
| 69 | mov pc, lr |
| 70 | |
| 71 | .section __ex_table, "a" |
| 72 | .long 1b, __get_user_bad |
| 73 | .long 2b, __get_user_bad |
| 74 | .long 3b, __get_user_bad |
| 75 | .long 4b, __get_user_bad |
| 76 | .long 5b, __get_user_bad_8 |
| 77 | .long 6b, __get_user_bad_8 |
| 78 | .previous |