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0aea86a2 CM |
1 | /* |
2 | * Copyright (C) 2012 ARM Ltd. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
15 | */ | |
16 | ||
17 | #include <linux/linkage.h> | |
18 | #include <asm/assembler.h> | |
19 | ||
20 | /* | |
21 | * Copy to user space from a kernel buffer (alignment handled by the hardware) | |
22 | * | |
23 | * Parameters: | |
24 | * x0 - to | |
25 | * x1 - from | |
26 | * x2 - n | |
27 | * Returns: | |
28 | * x0 - bytes not copied | |
29 | */ | |
30 | ENTRY(__copy_to_user) | |
31 | add x4, x0, x2 // upper user buffer boundary | |
32 | subs x2, x2, #8 | |
33 | b.mi 2f | |
34 | 1: | |
35 | ldr x3, [x1], #8 | |
36 | subs x2, x2, #8 | |
37 | USER(9f, str x3, [x0], #8 ) | |
38 | b.pl 1b | |
39 | 2: adds x2, x2, #4 | |
40 | b.mi 3f | |
41 | ldr w3, [x1], #4 | |
42 | sub x2, x2, #4 | |
43 | USER(9f, str w3, [x0], #4 ) | |
44 | 3: adds x2, x2, #2 | |
45 | b.mi 4f | |
46 | ldrh w3, [x1], #2 | |
47 | sub x2, x2, #2 | |
48 | USER(9f, strh w3, [x0], #2 ) | |
49 | 4: adds x2, x2, #1 | |
50 | b.mi 5f | |
51 | ldrb w3, [x1] | |
52 | USER(9f, strb w3, [x0] ) | |
53 | 5: mov x0, #0 | |
54 | ret | |
55 | ENDPROC(__copy_to_user) | |
56 | ||
57 | .section .fixup,"ax" | |
58 | .align 2 | |
59 | 9: sub x0, x4, x0 // bytes not copied | |
60 | ret | |
61 | .previous |