summaryrefslogtreecommitdiffstats
path: root/include/asm-generic/barrier.h
blob: 1cceca146905013dbe2c346020ad73fe3df68ce5 (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
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
/*
 * Generic barrier definitions, originally based on MN10300 definitions.
 *
 * It should be possible to use these on really simple architectures,
 * but it serves more as a starting point for new ports.
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#ifndef __ASM_GENERIC_BARRIER_H
#define __ASM_GENERIC_BARRIER_H

#ifndef __ASSEMBLY__

#include <linux/compiler.h>

#ifndef nop
#define nop()	asm volatile ("nop")
#endif

/*
 * Force strict CPU ordering. And yes, this is required on UP too when we're
 * talking to devices.
 *
 * Fall back to compiler barriers if nothing better is provided.
 */

#ifndef mb
#define mb()	barrier()
#endif

#ifndef rmb
#define rmb()	mb()
#endif

#ifndef wmb
#define wmb()	mb()
#endif

#ifndef dma_rmb
#define dma_rmb()	rmb()
#endif

#ifndef dma_wmb
#define dma_wmb()	wmb()
#endif

#ifndef read_barrier_depends
#define read_barrier_depends()		do { } while (0)
#endif

#ifndef __smp_mb
#define __smp_mb()	mb()
#endif

#ifndef __smp_rmb
#define __smp_rmb()	rmb()
#endif

#ifndef __smp_wmb
#define __smp_wmb()	wmb()
#endif

#ifndef __smp_read_barrier_depends
#define __smp_read_barrier_depends()	read_barrier_depends()
#endif

#ifdef CONFIG_SMP

#ifndef smp_mb
#define smp_mb()	__smp_mb()
#endif

#ifndef smp_rmb
#define smp_rmb()	__smp_rmb()
#endif

#ifndef smp_wmb
#define smp_wmb()	__smp_wmb()
#endif

#ifndef smp_read_barrier_depends
#define smp_read_barrier_depends()	__smp_read_barrier_depends()
#endif

#else	/* !CONFIG_SMP */

#ifndef smp_mb
#define smp_mb()	barrier()
#endif

#ifndef smp_rmb
#define smp_rmb()	barrier()
#endif

#ifndef smp_wmb
#define smp_wmb()	barrier()
#endif

#ifndef smp_read_barrier_depends
#define smp_read_barrier_depends()	do { } while (0)
#endif

#endif	/* CONFIG_SMP */

#ifndef __smp_store_mb
#define __smp_store_mb(var, value)  do { WRITE_ONCE(var, value); __smp_mb(); } while (0)
#endif

#ifndef __smp_mb__before_atomic
#define __smp_mb__before_atomic()	__smp_mb()
#endif

#ifndef __smp_mb__after_atomic
#define __smp_mb__after_atomic()	__smp_mb()
#endif

#ifndef __smp_store_release
#define __smp_store_release(p, v)					\
do {									\
	compiletime_assert_atomic_type(*p);				\
	__smp_mb();							\
	WRITE_ONCE(*p, v);						\
} while (0)
#endif

#ifndef __smp_load_acquire
#define __smp_load_acquire(p)						\
({									\
	typeof(*p) ___p1 = READ_ONCE(*p);				\
	compiletime_assert_atomic_type(*p);				\
	__smp_mb();							\
	___p1;								\
})
#endif

#ifdef CONFIG_SMP

#ifndef smp_store_mb
#define smp_store_mb(var, value)  __smp_store_mb(var, value)
#endif

#ifndef smp_mb__before_atomic
#define smp_mb__before_atomic()	__smp_mb__before_atomic()
#endif

#ifndef smp_mb__after_atomic
#define smp_mb__after_atomic()	__smp_mb__after_atomic()
#endif

#ifndef smp_store_release
#define smp_store_release(p, v) __smp_store_release(p, v)
#endif

#ifndef smp_load_acquire
#define smp_load_acquire(p) __smp_load_acquire(p)
#endif

#else	/* !CONFIG_SMP */

#ifndef smp_store_mb
#define smp_store_mb(var, value)  do { WRITE_ONCE(var, value); barrier(); } while (0)
#endif

#ifndef smp_mb__before_atomic
#define smp_mb__before_atomic()	barrier()
#endif

#ifndef smp_mb__after_atomic
#define smp_mb__after_atomic()	barrier()
#endif

#ifndef smp_store_release
#define smp_store_release(p, v)						\
do {									\
	compiletime_assert_atomic_type(*p);				\
	barrier();							\
	WRITE_ONCE(*p, v);						\
} while (0)
#endif

#ifndef smp_load_acquire
#define smp_load_acquire(p)						\
({									\
	typeof(*p) ___p1 = READ_ONCE(*p);				\
	compiletime_assert_atomic_type(*p);				\
	barrier();							\
	___p1;								\
})
#endif

#endif

/* Barriers for virtual machine guests when talking to an SMP host */
#define virt_mb() __smp_mb()
#define virt_rmb() __smp_rmb()
#define virt_wmb() __smp_wmb()
#define virt_read_barrier_depends() __smp_read_barrier_depends()
#define virt_store_mb(var, value) __smp_store_mb(var, value)
#define virt_mb__before_atomic() __smp_mb__before_atomic()
#define virt_mb__after_atomic()	__smp_mb__after_atomic()
#define virt_store_release(p, v) __smp_store_release(p, v)
#define virt_load_acquire(p) __smp_load_acquire(p)

#endif /* !__ASSEMBLY__ */
#endif /* __ASM_GENERIC_BARRIER_H */