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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 | |
19 | * Outputs: r0 is the error code | |
20 | * r2, r3 contains the zero-extended value | |
21 | * lr corrupted | |
22 | * | |
4baa9922 | 23 | * No other registers must be altered. (see <asm/uaccess.h> |
1da177e4 LT |
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 | */ | |
1da177e4 LT |
29 | #include <asm/errno.h> |
30 | ||
31 | .global __get_user_1 | |
32 | __get_user_1: | |
33 | 1: ldrbt r2, [r0] | |
34 | mov r0, #0 | |
35 | mov pc, lr | |
36 | ||
37 | .global __get_user_2 | |
38 | __get_user_2: | |
39 | 2: ldrbt r2, [r0], #1 | |
40 | 3: ldrbt r3, [r0] | |
41 | #ifndef __ARMEB__ | |
42 | orr r2, r2, r3, lsl #8 | |
43 | #else | |
44 | orr r2, r3, r2, lsl #8 | |
45 | #endif | |
46 | mov r0, #0 | |
47 | mov pc, lr | |
48 | ||
49 | .global __get_user_4 | |
50 | __get_user_4: | |
51 | 4: ldrt r2, [r0] | |
52 | mov r0, #0 | |
53 | mov pc, lr | |
54 | ||
1da177e4 LT |
55 | __get_user_bad: |
56 | mov r2, #0 | |
57 | mov r0, #-EFAULT | |
58 | mov pc, lr | |
59 | ||
60 | .section __ex_table, "a" | |
61 | .long 1b, __get_user_bad | |
62 | .long 2b, __get_user_bad | |
63 | .long 3b, __get_user_bad | |
64 | .long 4b, __get_user_bad | |
1da177e4 | 65 | .previous |