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1da177e4 LT |
1 | /* |
2 | * linux/arch/arm/lib/strncpy_from_user.S | |
3 | * | |
4 | * Copyright (C) 1995-2000 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 | #include <linux/linkage.h> | |
11 | #include <asm/assembler.h> | |
12 | #include <asm/errno.h> | |
13 | ||
14 | .text | |
15 | .align 5 | |
16 | ||
17 | /* | |
18 | * Copy a string from user space to kernel space. | |
19 | * r0 = dst, r1 = src, r2 = byte length | |
20 | * returns the number of characters copied (strlen of copied string), | |
21 | * -EFAULT on exception, or "len" if we fill the whole buffer | |
22 | */ | |
23 | ENTRY(__arch_strncpy_from_user) | |
24 | save_lr | |
25 | mov ip, r1 | |
26 | 1: subs r2, r2, #1 | |
27 | USER( ldrplbt r3, [r1], #1) | |
28 | bmi 2f | |
29 | strb r3, [r0], #1 | |
30 | teq r3, #0 | |
31 | bne 1b | |
32 | sub r1, r1, #1 @ take NUL character out of count | |
33 | 2: sub r0, r1, ip | |
34 | restore_pc | |
35 | ||
36 | .section .fixup,"ax" | |
37 | .align 0 | |
38 | 9001: mov r3, #0 | |
39 | strb r3, [r0, #0] @ null terminate | |
40 | mov r0, #-EFAULT | |
41 | restore_pc | |
42 | .previous | |
43 |