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5f97f7f9 HS |
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 <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 | |
28 | copy_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 | |
36 | copy_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 */ | |
49 | 1: sub r10, 4 | |
50 | brlt 3f | |
51 | ||
52 | 2: | |
53 | 10: ld.w r8, r11++ | |
54 | 11: st.w r12++, r8 | |
55 | sub r10, 4 | |
56 | brge 2b | |
57 | ||
58 | 3: 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 | */ | |
65 | 4: | |
66 | 20: ld.ub r8, r11++ | |
67 | 21: st.b r12++, r8 | |
68 | sub r10, 1 | |
69 | reteq 0 | |
70 | 22: ld.ub r8, r11++ | |
71 | 23: st.b r12++, r8 | |
72 | sub r10, 1 | |
73 | reteq 0 | |
74 | 24: ld.ub r8, r11++ | |
75 | 25: st.b r12++, r8 | |
76 | retal 0 | |
77 | ||
78 | /* Handle unaligned from-pointer */ | |
79 | 6: cp.w r10, 4 | |
80 | brlt 4b | |
81 | rsub r9, r9, 4 | |
82 | ||
83 | 30: ld.ub r8, r11++ | |
84 | 31: st.b r12++, r8 | |
85 | sub r10, 1 | |
86 | sub r9, 1 | |
87 | breq 1b | |
88 | 32: ld.ub r8, r11++ | |
89 | 33: st.b r12++, r8 | |
90 | sub r10, 1 | |
91 | sub r9, 1 | |
92 | breq 1b | |
93 | 34: ld.ub r8, r11++ | |
94 | 35: 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 | |
101 | 19: sub r10, -4 | |
102 | 29: 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 |