Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/avr32/lib/strncpy_from_user.S
10817 views
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"

30
strncpy_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


43
1:	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


50
2:	sub	r10, r9

51
	retal	r10

52


53
	.section .fixup, "ax"

54
	.align	1

55
3:	mov	r12, -EFAULT

56
	retal	r12

57


58
	.section __ex_table, "a"

59
	.align	2

60
	.long	1b, 3b

61


62