xref: /openbmc/linux/arch/arm64/lib/copy_to_user.S (revision b4b8664d)
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
19#include <asm/cache.h>
20#include <asm/asm-uaccess.h>
21
22/*
23 * Copy to user space from a kernel buffer (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	.macro ldrb1 ptr, regB, val
33	ldrb  \ptr, [\regB], \val
34	.endm
35
36	.macro strb1 ptr, regB, val
37	uao_user_alternative 9998f, strb, sttrb, \ptr, \regB, \val
38	.endm
39
40	.macro ldrh1 ptr, regB, val
41	ldrh  \ptr, [\regB], \val
42	.endm
43
44	.macro strh1 ptr, regB, val
45	uao_user_alternative 9998f, strh, sttrh, \ptr, \regB, \val
46	.endm
47
48	.macro ldr1 ptr, regB, val
49	ldr \ptr, [\regB], \val
50	.endm
51
52	.macro str1 ptr, regB, val
53	uao_user_alternative 9998f, str, sttr, \ptr, \regB, \val
54	.endm
55
56	.macro ldp1 ptr, regB, regC, val
57	ldp \ptr, \regB, [\regC], \val
58	.endm
59
60	.macro stp1 ptr, regB, regC, val
61	uao_stp 9998f, \ptr, \regB, \regC, \val
62	.endm
63
64end	.req	x5
65ENTRY(__arch_copy_to_user)
66	uaccess_enable_not_uao x3, x4
67	add	end, x0, x2
68#include "copy_template.S"
69	uaccess_disable_not_uao x3
70	mov	x0, #0
71	ret
72ENDPROC(__arch_copy_to_user)
73
74	.section .fixup,"ax"
75	.align	2
769998:	sub	x0, end, dst			// bytes not copied
77	ret
78	.previous
79