blob: 9ed8b987185b45b1157993abf4b0fe5a6c0b23a8 [file] [log] [blame]
Arnd Bergmann3f7e2122009-05-13 22:56:35 +00001/*
Arun Sharmaacac43e2011-07-26 16:09:08 -07002 * Generic C implementation of atomic counter operations. Usable on
3 * UP systems only. Do not include in machine independent code.
4 *
Arnd Bergmann3f7e2122009-05-13 22:56:35 +00005 * Originally implemented for MN10300.
6 *
7 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
8 * Written by David Howells (dhowells@redhat.com)
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public Licence
12 * as published by the Free Software Foundation; either version
13 * 2 of the Licence, or (at your option) any later version.
14 */
15#ifndef __ASM_GENERIC_ATOMIC_H
16#define __ASM_GENERIC_ATOMIC_H
17
David Howells34484272012-03-28 18:30:03 +010018#include <asm/cmpxchg.h>
Peter Zijlstrafebdbfe2014-02-06 18:16:07 +010019#include <asm/barrier.h>
David Howells34484272012-03-28 18:30:03 +010020
Peter Zijlstra560cb122014-04-23 16:12:30 +020021/*
22 * atomic_$op() - $op integer to atomic variable
23 * @i: integer value to $op
24 * @v: pointer to the atomic variable
25 *
26 * Atomically $ops @i to @v. Does not strictly guarantee a memory-barrier, use
27 * smp_mb__{before,after}_atomic().
28 */
29
30/*
31 * atomic_$op_return() - $op interer to atomic variable and returns the result
32 * @i: integer value to $op
33 * @v: pointer to the atomic variable
34 *
35 * Atomically $ops @i to @v. Does imply a full memory barrier.
36 */
37
Arnd Bergmann3f7e2122009-05-13 22:56:35 +000038#ifdef CONFIG_SMP
Peter Zijlstra560cb122014-04-23 16:12:30 +020039
40/* we can build all atomic primitives from cmpxchg */
41
42#define ATOMIC_OP(op, c_op) \
43static inline void atomic_##op(int i, atomic_t *v) \
44{ \
45 int c, old; \
46 \
47 c = v->counter; \
48 while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
49 c = old; \
50}
51
52#define ATOMIC_OP_RETURN(op, c_op) \
53static inline int atomic_##op##_return(int i, atomic_t *v) \
54{ \
55 int c, old; \
56 \
57 c = v->counter; \
58 while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
59 c = old; \
60 \
61 return c c_op i; \
62}
63
Peter Zijlstra28aa2bd2016-04-18 00:54:38 +020064#define ATOMIC_FETCH_OP(op, c_op) \
65static inline int atomic_fetch_##op(int i, atomic_t *v) \
66{ \
67 int c, old; \
68 \
69 c = v->counter; \
70 while ((old = cmpxchg(&v->counter, c, c c_op i)) != c) \
71 c = old; \
72 \
73 return c; \
74}
75
Peter Zijlstra560cb122014-04-23 16:12:30 +020076#else
77
78#include <linux/irqflags.h>
79
80#define ATOMIC_OP(op, c_op) \
81static inline void atomic_##op(int i, atomic_t *v) \
82{ \
83 unsigned long flags; \
84 \
85 raw_local_irq_save(flags); \
86 v->counter = v->counter c_op i; \
87 raw_local_irq_restore(flags); \
88}
89
90#define ATOMIC_OP_RETURN(op, c_op) \
91static inline int atomic_##op##_return(int i, atomic_t *v) \
92{ \
93 unsigned long flags; \
94 int ret; \
95 \
96 raw_local_irq_save(flags); \
97 ret = (v->counter = v->counter c_op i); \
98 raw_local_irq_restore(flags); \
99 \
100 return ret; \
101}
102
Peter Zijlstra28aa2bd2016-04-18 00:54:38 +0200103#define ATOMIC_FETCH_OP(op, c_op) \
104static inline int atomic_fetch_##op(int i, atomic_t *v) \
105{ \
106 unsigned long flags; \
107 int ret; \
108 \
109 raw_local_irq_save(flags); \
110 ret = v->counter; \
111 v->counter = v->counter c_op i; \
112 raw_local_irq_restore(flags); \
113 \
114 return ret; \
115}
116
Peter Zijlstra560cb122014-04-23 16:12:30 +0200117#endif /* CONFIG_SMP */
118
119#ifndef atomic_add_return
120ATOMIC_OP_RETURN(add, +)
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000121#endif
122
Peter Zijlstra560cb122014-04-23 16:12:30 +0200123#ifndef atomic_sub_return
124ATOMIC_OP_RETURN(sub, -)
125#endif
126
Peter Zijlstra28aa2bd2016-04-18 00:54:38 +0200127#ifndef atomic_fetch_add
128ATOMIC_FETCH_OP(add, +)
129#endif
130
131#ifndef atomic_fetch_sub
132ATOMIC_FETCH_OP(sub, -)
133#endif
134
135#ifndef atomic_fetch_and
136ATOMIC_FETCH_OP(and, &)
137#endif
138
139#ifndef atomic_fetch_or
Peter Zijlstra28aa2bd2016-04-18 00:54:38 +0200140ATOMIC_FETCH_OP(or, |)
141#endif
142
143#ifndef atomic_fetch_xor
144ATOMIC_FETCH_OP(xor, ^)
145#endif
146
Peter Zijlstra56d1def2015-07-15 15:47:25 +0200147#ifndef atomic_and
Peter Zijlstra560cb122014-04-23 16:12:30 +0200148ATOMIC_OP(and, &)
Peter Zijlstra56d1def2015-07-15 15:47:25 +0200149#endif
150
Peter Zijlstra56d1def2015-07-15 15:47:25 +0200151#ifndef atomic_or
Peter Zijlstra560cb122014-04-23 16:12:30 +0200152ATOMIC_OP(or, |)
Peter Zijlstra56d1def2015-07-15 15:47:25 +0200153#endif
154
Peter Zijlstrae6942b72014-04-23 19:32:50 +0200155#ifndef atomic_xor
156ATOMIC_OP(xor, ^)
Peter Zijlstra560cb122014-04-23 16:12:30 +0200157#endif
158
Peter Zijlstra28aa2bd2016-04-18 00:54:38 +0200159#undef ATOMIC_FETCH_OP
Peter Zijlstra560cb122014-04-23 16:12:30 +0200160#undef ATOMIC_OP_RETURN
161#undef ATOMIC_OP
162
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000163/*
164 * Atomic operations that C can't guarantee us. Useful for
165 * resource counting etc..
166 */
167
168#define ATOMIC_INIT(i) { (i) }
169
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000170/**
171 * atomic_read - read atomic variable
172 * @v: pointer of type atomic_t
173 *
Peter Fritzsche37682172010-05-24 14:33:09 -0700174 * Atomically reads the value of @v.
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000175 */
Mike Frysinger7505cb62011-07-26 16:09:11 -0700176#ifndef atomic_read
Peter Zijlstra62e8a322015-09-18 11:13:10 +0200177#define atomic_read(v) READ_ONCE((v)->counter)
Mike Frysinger7505cb62011-07-26 16:09:11 -0700178#endif
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000179
180/**
181 * atomic_set - set atomic variable
182 * @v: pointer of type atomic_t
183 * @i: required value
184 *
Peter Fritzsche37682172010-05-24 14:33:09 -0700185 * Atomically sets the value of @v to @i.
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000186 */
Peter Zijlstra62e8a322015-09-18 11:13:10 +0200187#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000188
David Howellsdf9ee292010-10-07 14:08:55 +0100189#include <linux/irqflags.h>
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000190
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000191static inline int atomic_add_negative(int i, atomic_t *v)
192{
193 return atomic_add_return(i, v) < 0;
194}
195
196static inline void atomic_add(int i, atomic_t *v)
197{
198 atomic_add_return(i, v);
199}
200
201static inline void atomic_sub(int i, atomic_t *v)
202{
203 atomic_sub_return(i, v);
204}
205
206static inline void atomic_inc(atomic_t *v)
207{
208 atomic_add_return(1, v);
209}
210
211static inline void atomic_dec(atomic_t *v)
212{
213 atomic_sub_return(1, v);
214}
215
216#define atomic_dec_return(v) atomic_sub_return(1, (v))
217#define atomic_inc_return(v) atomic_add_return(1, (v))
218
219#define atomic_sub_and_test(i, v) (atomic_sub_return((i), (v)) == 0)
Mike Frysinger3eea44e2011-07-26 16:09:09 -0700220#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
221#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000222
Mathieu Lacage8b9d4062010-06-27 12:26:06 +0200223#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
224#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
225
Arun Sharmaf24219b2011-07-26 16:09:07 -0700226static inline int __atomic_add_unless(atomic_t *v, int a, int u)
Mathieu Lacage8b9d4062010-06-27 12:26:06 +0200227{
Peter Zijlstra560cb122014-04-23 16:12:30 +0200228 int c, old;
229 c = atomic_read(v);
230 while (c != u && (old = atomic_cmpxchg(v, c, c + a)) != c)
231 c = old;
232 return c;
Mathieu Lacage8b9d4062010-06-27 12:26:06 +0200233}
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000234
Arnd Bergmann3f7e2122009-05-13 22:56:35 +0000235#endif /* __ASM_GENERIC_ATOMIC_H */