xref: /openbmc/linux/arch/arm64/lib/copy_to_user.S (revision 295cf156)
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2012 ARM Ltd.
4 */
5
6#include <linux/linkage.h>
7
8#include <asm/asm-uaccess.h>
9#include <asm/assembler.h>
10#include <asm/cache.h>
11
12/*
13 * Copy to user space from a kernel buffer (alignment handled by the hardware)
14 *
15 * Parameters:
16 *	x0 - to
17 *	x1 - from
18 *	x2 - n
19 * Returns:
20 *	x0 - bytes not copied
21 */
22	.macro ldrb1 reg, ptr, val
23	ldrb  \reg, [\ptr], \val
24	.endm
25
26	.macro strb1 reg, ptr, val
27	user_ldst 9998f, sttrb, \reg, \ptr, \val
28	.endm
29
30	.macro ldrh1 reg, ptr, val
31	ldrh  \reg, [\ptr], \val
32	.endm
33
34	.macro strh1 reg, ptr, val
35	user_ldst 9997f, sttrh, \reg, \ptr, \val
36	.endm
37
38	.macro ldr1 reg, ptr, val
39	ldr \reg, [\ptr], \val
40	.endm
41
42	.macro str1 reg, ptr, val
43	user_ldst 9997f, sttr, \reg, \ptr, \val
44	.endm
45
46	.macro ldp1 reg1, reg2, ptr, val
47	ldp \reg1, \reg2, [\ptr], \val
48	.endm
49
50	.macro stp1 reg1, reg2, ptr, val
51	user_stp 9997f, \reg1, \reg2, \ptr, \val
52	.endm
53
54end	.req	x5
55srcin	.req	x15
56SYM_FUNC_START(__arch_copy_to_user)
57	add	end, x0, x2
58	mov	srcin, x1
59#include "copy_template.S"
60	mov	x0, #0
61	ret
62SYM_FUNC_END(__arch_copy_to_user)
63EXPORT_SYMBOL(__arch_copy_to_user)
64
65	.section .fixup,"ax"
66	.align	2
679997:	cmp	dst, dstin
68	b.ne	9998f
69	// Before being absolutely sure we couldn't copy anything, try harder
70	ldrb	tmp1w, [srcin]
71USER(9998f, sttrb tmp1w, [dst])
72	add	dst, dst, #1
739998:	sub	x0, end, dst			// bytes not copied
74	ret
75	.previous
76