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
54 .macro cpy1 dst, src, count
55 .arch_extension mops
56 USER_CPY(9997f, 1, cpyfpwt [\dst]!, [\src]!, \count!)
57 USER_CPY(9996f, 1, cpyfmwt [\dst]!, [\src]!, \count!)
58 USER_CPY(9996f, 1, cpyfewt [\dst]!, [\src]!, \count!)
59 .endm
60
61end .req x5
62srcin .req x15
63SYM_FUNC_START(__arch_copy_to_user)
64 add end, x0, x2
65 mov srcin, x1
66#include "copy_template.S"
67 mov x0, #0
68 ret
69
70 // Exception fixups
719996: b.cs 9997f
72 // Registers are in Option A format
73 add dst, dst, count
749997: cmp dst, dstin
75 b.ne 9998f
76 // Before being absolutely sure we couldn't copy anything, try harder
77 ldrb tmp1w, [srcin]
78USER(9998f, sttrb tmp1w, [dst])
79 add dst, dst, #1
809998: sub x0, end, dst // bytes not copied
81 ret
82SYM_FUNC_END(__arch_copy_to_user)
83EXPORT_SYMBOL(__arch_copy_to_user)
84

source code of linux/arch/arm64/lib/copy_to_user.S