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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 <asm/page.h>
11#include <asm/thread_info.h>
12#include <asm/asm.h>
13
14 /*
15 * __kernel_size_t
16 * __copy_user(void *to, const void *from, __kernel_size_t n)
17 *
18 * Returns the number of bytes not copied. Might be off by
19 * max 3 bytes if we get a fault in the main loop.
20 *
21 * The address-space checking functions simply fall through to
22 * the non-checking version.
23 */
24 .text
25 .align 1
26 .global copy_from_user
27 .type copy_from_user, @function
28copy_from_user:
29 branch_if_kernel r8, __copy_user
30 ret_if_privileged r8, r11, r10, r10
31 rjmp __copy_user
32 .size copy_from_user, . - copy_from_user
33
34 .global copy_to_user
35 .type copy_to_user, @function
36copy_to_user:
37 branch_if_kernel r8, __copy_user
38 ret_if_privileged r8, r12, r10, r10
39 .size copy_to_user, . - copy_to_user
40
41 .global __copy_user
42 .type __copy_user, @function
43__copy_user:
44 mov r9, r11
45 andl r9, 3, COH
46 brne 6f
47
48 /* At this point, from is word-aligned */
491: sub r10, 4
50 brlt 3f
51
522:
5310: ld.w r8, r11++
5411: st.w r12++, r8
55 sub r10, 4
56 brge 2b
57
583: sub r10, -4
59 reteq 0
60
61 /*
62 * Handle unaligned count. Need to be careful with r10 here so
63 * that we return the correct value even if we get a fault
64 */
654:
6620: ld.ub r8, r11++
6721: st.b r12++, r8
68 sub r10, 1
69 reteq 0
7022: ld.ub r8, r11++
7123: st.b r12++, r8
72 sub r10, 1
73 reteq 0
7424: ld.ub r8, r11++
7525: st.b r12++, r8
76 retal 0
77
78 /* Handle unaligned from-pointer */
796: cp.w r10, 4
80 brlt 4b
81 rsub r9, r9, 4
82
8330: ld.ub r8, r11++
8431: st.b r12++, r8
85 sub r10, 1
86 sub r9, 1
87 breq 1b
8832: ld.ub r8, r11++
8933: st.b r12++, r8
90 sub r10, 1
91 sub r9, 1
92 breq 1b
9334: ld.ub r8, r11++
9435: st.b r12++, r8
95 sub r10, 1
96 rjmp 1b
97 .size __copy_user, . - __copy_user
98
99 .section .fixup,"ax"
100 .align 1
10119: sub r10, -4
10229: retal r10
103
104 .section __ex_table,"a"
105 .align 2
106 .long 10b, 19b
107 .long 11b, 19b
108 .long 20b, 29b
109 .long 21b, 29b
110 .long 22b, 29b
111 .long 23b, 29b
112 .long 24b, 29b
113 .long 25b, 29b
114 .long 30b, 29b
115 .long 31b, 29b
116 .long 32b, 29b
117 .long 33b, 29b
118 .long 34b, 29b
119 .long 35b, 29b