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