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1da177e4 LT |
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 | |
8404663f | 19 | * r1 contains the address limit, which must be preserved |
1da177e4 | 20 | * Outputs: r0 is the error code |
8404663f | 21 | * r2 contains the zero-extended value |
1da177e4 LT |
22 | * lr corrupted |
23 | * | |
4baa9922 | 24 | * No other registers must be altered. (see <asm/uaccess.h> |
1da177e4 LT |
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 | */ | |
93ed3970 | 30 | #include <linux/linkage.h> |
8404663f | 31 | #include <asm/assembler.h> |
1da177e4 | 32 | #include <asm/errno.h> |
247055aa | 33 | #include <asm/domain.h> |
1da177e4 | 34 | |
93ed3970 | 35 | ENTRY(__get_user_1) |
8404663f | 36 | check_uaccess r0, 1, r1, r2, __get_user_bad |
4e7682d0 | 37 | 1: TUSER(ldrb) r2, [r0] |
1da177e4 LT |
38 | mov r0, #0 |
39 | mov pc, lr | |
93ed3970 | 40 | ENDPROC(__get_user_1) |
1da177e4 | 41 | |
93ed3970 | 42 | ENTRY(__get_user_2) |
8404663f RK |
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 | |
8b592783 | 48 | #else |
8404663f RK |
49 | rb .req r0 |
50 | 2: ldrb r2, [r0] | |
51 | 3: ldrb rb, [r0, #1] | |
8b592783 | 52 | #endif |
1da177e4 | 53 | #ifndef __ARMEB__ |
8404663f | 54 | orr r2, r2, rb, lsl #8 |
1da177e4 | 55 | #else |
8404663f | 56 | orr r2, rb, r2, lsl #8 |
1da177e4 LT |
57 | #endif |
58 | mov r0, #0 | |
59 | mov pc, lr | |
93ed3970 | 60 | ENDPROC(__get_user_2) |
1da177e4 | 61 | |
93ed3970 | 62 | ENTRY(__get_user_4) |
8404663f | 63 | check_uaccess r0, 4, r1, r2, __get_user_bad |
4e7682d0 | 64 | 4: TUSER(ldr) r2, [r0] |
1da177e4 LT |
65 | mov r0, #0 |
66 | mov pc, lr | |
93ed3970 | 67 | ENDPROC(__get_user_4) |
1da177e4 | 68 | |
1da177e4 LT |
69 | __get_user_bad: |
70 | mov r2, #0 | |
71 | mov r0, #-EFAULT | |
72 | mov pc, lr | |
93ed3970 | 73 | ENDPROC(__get_user_bad) |
1da177e4 | 74 | |
4260415f | 75 | .pushsection __ex_table, "a" |
1da177e4 LT |
76 | .long 1b, __get_user_bad |
77 | .long 2b, __get_user_bad | |
78 | .long 3b, __get_user_bad | |
79 | .long 4b, __get_user_bad | |
4260415f | 80 | .popsection |