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Diffstat (limited to 'arch/arm/lib/strncpy_from_user.S')
-rw-r--r--arch/arm/lib/strncpy_from_user.S43
1 files changed, 43 insertions, 0 deletions
diff --git a/arch/arm/lib/strncpy_from_user.S b/arch/arm/lib/strncpy_from_user.S
new file mode 100644
index 000000000000..629cc8775276
--- /dev/null
+++ b/arch/arm/lib/strncpy_from_user.S
@@ -0,0 +1,43 @@
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 */
23ENTRY(__arch_strncpy_from_user)
24 save_lr
25 mov ip, r1
261: subs r2, r2, #1
27USER( 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
332: sub r0, r1, ip
34 restore_pc
35
36 .section .fixup,"ax"
37 .align 0
389001: mov r3, #0
39 strb r3, [r0, #0] @ null terminate
40 mov r0, #-EFAULT
41 restore_pc
42 .previous
43