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Catalin Marinas0aea86a2012-03-05 11:49:32 +00001/*
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 */
30ENTRY(__copy_to_user)
31 add x4, x0, x2 // upper user buffer boundary
32 subs x2, x2, #8
33 b.mi 2f
341:
35 ldr x3, [x1], #8
36 subs x2, x2, #8
37USER(9f, str x3, [x0], #8 )
38 b.pl 1b
392: adds x2, x2, #4
40 b.mi 3f
41 ldr w3, [x1], #4
42 sub x2, x2, #4
43USER(9f, str w3, [x0], #4 )
443: adds x2, x2, #2
45 b.mi 4f
46 ldrh w3, [x1], #2
47 sub x2, x2, #2
48USER(9f, strh w3, [x0], #2 )
494: adds x2, x2, #1
50 b.mi 5f
51 ldrb w3, [x1]
52USER(9f, strb w3, [x0] )
535: mov x0, #0
54 ret
55ENDPROC(__copy_to_user)
56
57 .section .fixup,"ax"
58 .align 2
599: sub x0, x4, x0 // bytes not copied
60 ret
61 .previous