blob: 1c9814f346c679b3ec708bbd47573033f34f8489 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 */
Russell King02fcb972006-06-21 14:44:52 +010023ENTRY(__strncpy_from_user)
Linus Torvalds1da177e2005-04-16 15:20:36 -070024 mov ip, r1
251: subs r2, r2, #1
Catalin Marinas8b592782009-07-24 12:32:57 +010026 ldrusr r3, r1, 1, pl
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 bmi 2f
28 strb r3, [r0], #1
29 teq r3, #0
30 bne 1b
31 sub r1, r1, #1 @ take NUL character out of count
322: sub r0, r1, ip
Russell King405040a2006-06-25 11:37:09 +010033 mov pc, lr
Catalin Marinas93ed3972008-08-28 11:22:32 +010034ENDPROC(__strncpy_from_user)
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
36 .section .fixup,"ax"
37 .align 0
389001: mov r3, #0
39 strb r3, [r0, #0] @ null terminate
40 mov r0, #-EFAULT
Russell King405040a2006-06-25 11:37:09 +010041 mov pc, lr
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 .previous
43