1/*
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
61