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Diffstat (limited to 'arch/arm64/lib/copy_in_user.S')
-rw-r--r-- | arch/arm64/lib/copy_in_user.S | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/arch/arm64/lib/copy_in_user.S b/arch/arm64/lib/copy_in_user.S new file mode 100644 index 00000000000..84b6c9bb9b9 --- /dev/null +++ b/arch/arm64/lib/copy_in_user.S | |||
@@ -0,0 +1,63 @@ | |||
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 | ||