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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 from user space to 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_from_user) | |
23e94994 WD |
31 | add x5, x1, x2 // upper user buffer boundary |
32 | subs x2, x2, #16 | |
33 | b.mi 1f | |
34 | 0: | |
35 | USER(9f, ldp x3, x4, [x1], #16) | |
36 | subs x2, x2, #16 | |
37 | stp x3, x4, [x0], #16 | |
38 | b.pl 0b | |
39 | 1: adds x2, x2, #8 | |
0aea86a2 | 40 | b.mi 2f |
0aea86a2 | 41 | USER(9f, ldr x3, [x1], #8 ) |
23e94994 | 42 | sub x2, x2, #8 |
0aea86a2 | 43 | str x3, [x0], #8 |
0aea86a2 CM |
44 | 2: adds x2, x2, #4 |
45 | b.mi 3f | |
46 | USER(9f, ldr w3, [x1], #4 ) | |
47 | sub x2, x2, #4 | |
48 | str w3, [x0], #4 | |
49 | 3: adds x2, x2, #2 | |
50 | b.mi 4f | |
51 | USER(9f, ldrh w3, [x1], #2 ) | |
52 | sub x2, x2, #2 | |
53 | strh w3, [x0], #2 | |
54 | 4: adds x2, x2, #1 | |
55 | b.mi 5f | |
56 | USER(9f, ldrb w3, [x1] ) | |
57 | strb w3, [x0] | |
58 | 5: mov x0, #0 | |
59 | ret | |
60 | ENDPROC(__copy_from_user) | |
61 | ||
62 | .section .fixup,"ax" | |
63 | .align 2 | |
23e94994 | 64 | 9: sub x2, x5, x1 |
0aea86a2 CM |
65 | mov x3, x2 |
66 | 10: strb wzr, [x0], #1 // zero remaining buffer space | |
67 | subs x3, x3, #1 | |
68 | b.ne 10b | |
69 | mov x0, x2 // bytes not copied | |
70 | ret | |
71 | .previous |