summaryrefslogtreecommitdiffstats
path: root/arch/s390/lib/mem.S
blob: 2311f15be9cf04b3bad1f766453e6ff970d53a83 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
/* SPDX-License-Identifier: GPL-2.0 */
/*
 * String handling functions.
 *
 * Copyright IBM Corp. 2012
 */

#include <linux/linkage.h>
#include <asm/export.h>
#include <asm/nospec-insn.h>

	GEN_BR_THUNK %r14

/*
 * void *memmove(void *dest, const void *src, size_t n)
 */
ENTRY(memmove)
	ltgr	%r4,%r4
	lgr	%r1,%r2
	bzr	%r14
	aghi	%r4,-1
	clgr	%r2,%r3
	jnh	.Lmemmove_forward
	la	%r5,1(%r4,%r3)
	clgr	%r2,%r5
	jl	.Lmemmove_reverse
.Lmemmove_forward:
	srlg	%r0,%r4,8
	ltgr	%r0,%r0
	jz	.Lmemmove_forward_remainder
.Lmemmove_forward_loop:
	mvc	0(256,%r1),0(%r3)
	la	%r1,256(%r1)
	la	%r3,256(%r3)
	brctg	%r0,.Lmemmove_forward_loop
.Lmemmove_forward_remainder:
	larl	%r5,.Lmemmove_mvc
	ex	%r4,0(%r5)
	BR_EX	%r14
.Lmemmove_reverse:
	ic	%r0,0(%r4,%r3)
	stc	%r0,0(%r4,%r1)
	brctg	%r4,.Lmemmove_reverse
	ic	%r0,0(%r4,%r3)
	stc	%r0,0(%r4,%r1)
	BR_EX	%r14
.Lmemmove_mvc:
	mvc	0(1,%r1),0(%r3)
EXPORT_SYMBOL(memmove)

/*
 * memset implementation
 *
 * This code corresponds to the C construct below. We do distinguish
 * between clearing (c == 0) and setting a memory array (c != 0) simply
 * because nearly all memset invocations in the kernel clear memory and
 * the xc instruction is preferred in such cases.
 *
 * void *memset(void *s, int c, size_t n)
 * {
 *	if (likely(c == 0))
 *		return __builtin_memset(s, 0, n);
 *	return __builtin_memset(s, c, n);
 * }
 */
ENTRY(memset)
	ltgr	%r4,%r4
	bzr	%r14
	ltgr	%r3,%r3
	jnz	.Lmemset_fill
	aghi	%r4,-1
	srlg	%r3,%r4,8
	ltgr	%r3,%r3
	lgr	%r1,%r2
	jz	.Lmemset_clear_remainder
.Lmemset_clear_loop:
	xc	0(256,%r1),0(%r1)
	la	%r1,256(%r1)
	brctg	%r3,.Lmemset_clear_loop
.Lmemset_clear_remainder:
	larl	%r3,.Lmemset_xc
	ex	%r4,0(%r3)
	BR_EX	%r14
.Lmemset_fill:
	cghi	%r4,1
	lgr	%r1,%r2
	je	.Lmemset_fill_exit
	aghi	%r4,-2
	srlg	%r5,%r4,8
	ltgr	%r5,%r5
	jz	.Lmemset_fill_remainder
.Lmemset_fill_loop:
	stc	%r3,0(%r1)
	mvc	1(255,%r1),0(%r1)
	la	%r1,256(%r1)
	brctg	%r5,.Lmemset_fill_loop
.Lmemset_fill_remainder:
	stc	%r3,0(%r1)
	larl	%r5,.Lmemset_mvc
	ex	%r4,0(%r5)
	BR_EX	%r14
.Lmemset_fill_exit:
	stc	%r3,0(%r1)
	BR_EX	%r14
.Lmemset_xc:
	xc	0(1,%r1),0(%r1)
.Lmemset_mvc:
	mvc	1(1,%r1),0(%r1)
EXPORT_SYMBOL(memset)

/*
 * memcpy implementation
 *
 * void *memcpy(void *dest, const void *src, size_t n)
 */
ENTRY(memcpy)
	ltgr	%r4,%r4
	bzr	%r14
	aghi	%r4,-1
	srlg	%r5,%r4,8
	ltgr	%r5,%r5
	lgr	%r1,%r2
	jnz	.Lmemcpy_loop
.Lmemcpy_remainder:
	larl	%r5,.Lmemcpy_mvc
	ex	%r4,0(%r5)
	BR_EX	%r14
.Lmemcpy_loop:
	mvc	0(256,%r1),0(%r3)
	la	%r1,256(%r1)
	la	%r3,256(%r3)
	brctg	%r5,.Lmemcpy_loop
	j	.Lmemcpy_remainder
.Lmemcpy_mvc:
	mvc	0(1,%r1),0(%r3)
EXPORT_SYMBOL(memcpy)

/*
 * __memset16/32/64
 *
 * void *__memset16(uint16_t *s, uint16_t v, size_t count)
 * void *__memset32(uint32_t *s, uint32_t v, size_t count)
 * void *__memset64(uint64_t *s, uint64_t v, size_t count)
 */
.macro __MEMSET bits,bytes,insn
ENTRY(__memset\bits)
	ltgr	%r4,%r4
	bzr	%r14
	cghi	%r4,\bytes
	je	.L__memset_exit\bits
	aghi	%r4,-(\bytes+1)
	srlg	%r5,%r4,8
	ltgr	%r5,%r5
	lgr	%r1,%r2
	jz	.L__memset_remainder\bits
.L__memset_loop\bits:
	\insn	%r3,0(%r1)
	mvc	\bytes(256-\bytes,%r1),0(%r1)
	la	%r1,256(%r1)
	brctg	%r5,.L__memset_loop\bits
.L__memset_remainder\bits:
	\insn	%r3,0(%r1)
	larl	%r5,.L__memset_mvc\bits
	ex	%r4,0(%r5)
	BR_EX	%r14
.L__memset_exit\bits:
	\insn	%r3,0(%r2)
	BR_EX	%r14
.L__memset_mvc\bits:
	mvc	\bytes(1,%r1),0(%r1)
.endm

__MEMSET 16,2,sth
EXPORT_SYMBOL(__memset16)

__MEMSET 32,4,st
EXPORT_SYMBOL(__memset32)

__MEMSET 64,8,stg
EXPORT_SYMBOL(__memset64)