| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -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 | * r1 contains the address limit, which must be preserved |
| 20 | * Outputs: r0 is the error code |
| 21 | * r2 contains the zero-extended value |
| 22 | * lr corrupted |
| 23 | * |
| 24 | * No other registers must be altered. (see <asm/uaccess.h> |
| 25 | * for specific ASM register usage). |
| 26 | * |
| 27 | * Note that ADDR_LIMIT is either 0 or 0xc0000000. |
| 28 | * Note also that it is intended that __get_user_bad is not global. |
| 29 | */ |
| 30 | #include <linux/linkage.h> |
| 31 | #include <asm/assembler.h> |
| 32 | #include <asm/errno.h> |
| 33 | #include <asm/domain.h> |
| 34 | |
| 35 | ENTRY(__get_user_1) |
| 36 | check_uaccess r0, 1, r1, r2, __get_user_bad |
| 37 | 1: TUSER(ldrb) r2, [r0] |
| 38 | mov r0, #0 |
| 39 | mov pc, lr |
| 40 | ENDPROC(__get_user_1) |
| 41 | |
| 42 | ENTRY(__get_user_2) |
| 43 | check_uaccess r0, 2, r1, r2, __get_user_bad |
| 44 | #ifdef CONFIG_CPU_USE_DOMAINS |
| 45 | rb .req ip |
| 46 | 2: ldrbt r2, [r0], #1 |
| 47 | 3: ldrbt rb, [r0], #0 |
| 48 | #else |
| 49 | rb .req r0 |
| 50 | 2: ldrb r2, [r0] |
| 51 | 3: ldrb rb, [r0, #1] |
| 52 | #endif |
| 53 | #ifndef __ARMEB__ |
| 54 | orr r2, r2, rb, lsl #8 |
| 55 | #else |
| 56 | orr r2, rb, r2, lsl #8 |
| 57 | #endif |
| 58 | mov r0, #0 |
| 59 | mov pc, lr |
| 60 | ENDPROC(__get_user_2) |
| 61 | |
| 62 | ENTRY(__get_user_4) |
| 63 | check_uaccess r0, 4, r1, r2, __get_user_bad |
| 64 | 4: TUSER(ldr) r2, [r0] |
| 65 | mov r0, #0 |
| 66 | mov pc, lr |
| 67 | ENDPROC(__get_user_4) |
| 68 | |
| 69 | __get_user_bad: |
| 70 | mov r2, #0 |
| 71 | mov r0, #-EFAULT |
| 72 | mov pc, lr |
| 73 | ENDPROC(__get_user_bad) |
| 74 | |
| 75 | .pushsection __ex_table, "a" |
| 76 | .long 1b, __get_user_bad |
| 77 | .long 2b, __get_user_bad |
| 78 | .long 3b, __get_user_bad |
| 79 | .long 4b, __get_user_bad |
| 80 | .popsection |