blob: 72bd50599ec6c2b2e81e0043d09e4d4882211486 [file] [log] [blame]
Haavard Skinnemoen5f97f7f2006-09-25 23:32:13 -07001/*
2 * Copy to/from userspace with optional address space checking.
3 *
4 * Copyright 2004-2006 Atmel Corporation
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/errno.h>
11
12#include <asm/page.h>
13#include <asm/thread_info.h>
14#include <asm/asm.h>
15
16 /*
17 * long strncpy_from_user(char *dst, const char *src, long count)
18 *
19 * On success, returns the length of the string, not including
20 * the terminating NUL.
21 *
22 * If the string is longer than count, returns count
23 *
24 * If userspace access fails, returns -EFAULT
25 */
26 .text
27 .align 1
28 .global strncpy_from_user
29 .type strncpy_from_user, "function"
30strncpy_from_user:
31 mov r9, -EFAULT
32 branch_if_kernel r8, __strncpy_from_user
33 ret_if_privileged r8, r11, r10, r9
34
35 .global __strncpy_from_user
36 .type __strncpy_from_user, "function"
37__strncpy_from_user:
38 cp.w r10, 0
39 reteq 0
40
41 mov r9, r10
42
431: ld.ub r8, r11++
44 st.b r12++, r8
45 cp.w r8, 0
46 breq 2f
47 sub r9, 1
48 brne 1b
49
502: sub r10, r9
51 retal r10
52
53 .section .fixup, "ax"
54 .align 1
553: mov r12, -EFAULT
56 retal r12
57
58 .section __ex_table, "a"
59 .align 2
60 .long 1b, 3b