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1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * Generic C implementation of atomic counter operations. Do not include in
4 * machine independent code.
5 *
6 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
7 * Written by David Howells (dhowells@redhat.com)
8 */
9#ifndef __ASM_GENERIC_ATOMIC_H
10#define __ASM_GENERIC_ATOMIC_H
11
12#include <asm/cmpxchg.h>
13#include <asm/barrier.h>
14
15#ifdef CONFIG_SMP
16
17/* we can build all atomic primitives from cmpxchg */
18
19#define ATOMIC_OP(op, c_op) \
20static inline void generic_atomic_##op(int i, atomic_t *v) \
21{ \
22 int c, old; \
23 \
24 c = v->counter; \
25 while ((old = arch_cmpxchg(&v->counter, c, c c_op i)) != c) \
26 c = old; \
27}
28
29#define ATOMIC_OP_RETURN(op, c_op) \
30static inline int generic_atomic_##op##_return(int i, atomic_t *v) \
31{ \
32 int c, old; \
33 \
34 c = v->counter; \
35 while ((old = arch_cmpxchg(&v->counter, c, c c_op i)) != c) \
36 c = old; \
37 \
38 return c c_op i; \
39}
40
41#define ATOMIC_FETCH_OP(op, c_op) \
42static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \
43{ \
44 int c, old; \
45 \
46 c = v->counter; \
47 while ((old = arch_cmpxchg(&v->counter, c, c c_op i)) != c) \
48 c = old; \
49 \
50 return c; \
51}
52
53#else
54
55#include <linux/irqflags.h>
56
57#define ATOMIC_OP(op, c_op) \
58static inline void generic_atomic_##op(int i, atomic_t *v) \
59{ \
60 unsigned long flags; \
61 \
62 raw_local_irq_save(flags); \
63 v->counter = v->counter c_op i; \
64 raw_local_irq_restore(flags); \
65}
66
67#define ATOMIC_OP_RETURN(op, c_op) \
68static inline int generic_atomic_##op##_return(int i, atomic_t *v) \
69{ \
70 unsigned long flags; \
71 int ret; \
72 \
73 raw_local_irq_save(flags); \
74 ret = (v->counter = v->counter c_op i); \
75 raw_local_irq_restore(flags); \
76 \
77 return ret; \
78}
79
80#define ATOMIC_FETCH_OP(op, c_op) \
81static inline int generic_atomic_fetch_##op(int i, atomic_t *v) \
82{ \
83 unsigned long flags; \
84 int ret; \
85 \
86 raw_local_irq_save(flags); \
87 ret = v->counter; \
88 v->counter = v->counter c_op i; \
89 raw_local_irq_restore(flags); \
90 \
91 return ret; \
92}
93
94#endif /* CONFIG_SMP */
95
96ATOMIC_OP_RETURN(add, +)
97ATOMIC_OP_RETURN(sub, -)
98
99ATOMIC_FETCH_OP(add, +)
100ATOMIC_FETCH_OP(sub, -)
101ATOMIC_FETCH_OP(and, &)
102ATOMIC_FETCH_OP(or, |)
103ATOMIC_FETCH_OP(xor, ^)
104
105ATOMIC_OP(add, +)
106ATOMIC_OP(sub, -)
107ATOMIC_OP(and, &)
108ATOMIC_OP(or, |)
109ATOMIC_OP(xor, ^)
110
111#undef ATOMIC_FETCH_OP
112#undef ATOMIC_OP_RETURN
113#undef ATOMIC_OP
114
115#define arch_atomic_add_return generic_atomic_add_return
116#define arch_atomic_sub_return generic_atomic_sub_return
117
118#define arch_atomic_fetch_add generic_atomic_fetch_add
119#define arch_atomic_fetch_sub generic_atomic_fetch_sub
120#define arch_atomic_fetch_and generic_atomic_fetch_and
121#define arch_atomic_fetch_or generic_atomic_fetch_or
122#define arch_atomic_fetch_xor generic_atomic_fetch_xor
123
124#define arch_atomic_add generic_atomic_add
125#define arch_atomic_sub generic_atomic_sub
126#define arch_atomic_and generic_atomic_and
127#define arch_atomic_or generic_atomic_or
128#define arch_atomic_xor generic_atomic_xor
129
130#define arch_atomic_read(v) READ_ONCE((v)->counter)
131#define arch_atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
132
133#endif /* __ASM_GENERIC_ATOMIC_H */
1/*
2 * Generic C implementation of atomic counter operations. Usable on
3 * UP systems only. Do not include in machine independent code.
4 *
5 * 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
18#include <asm/cmpxchg.h>
19#include <asm/barrier.h>
20
21/*
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
38#ifdef CONFIG_SMP
39
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
64#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
76#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
103#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
117#endif /* CONFIG_SMP */
118
119#ifndef atomic_add_return
120ATOMIC_OP_RETURN(add, +)
121#endif
122
123#ifndef atomic_sub_return
124ATOMIC_OP_RETURN(sub, -)
125#endif
126
127#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
140ATOMIC_FETCH_OP(or, |)
141#endif
142
143#ifndef atomic_fetch_xor
144ATOMIC_FETCH_OP(xor, ^)
145#endif
146
147#ifndef atomic_and
148ATOMIC_OP(and, &)
149#endif
150
151#ifndef atomic_or
152ATOMIC_OP(or, |)
153#endif
154
155#ifndef atomic_xor
156ATOMIC_OP(xor, ^)
157#endif
158
159#undef ATOMIC_FETCH_OP
160#undef ATOMIC_OP_RETURN
161#undef ATOMIC_OP
162
163/*
164 * Atomic operations that C can't guarantee us. Useful for
165 * resource counting etc..
166 */
167
168#define ATOMIC_INIT(i) { (i) }
169
170/**
171 * atomic_read - read atomic variable
172 * @v: pointer of type atomic_t
173 *
174 * Atomically reads the value of @v.
175 */
176#ifndef atomic_read
177#define atomic_read(v) READ_ONCE((v)->counter)
178#endif
179
180/**
181 * atomic_set - set atomic variable
182 * @v: pointer of type atomic_t
183 * @i: required value
184 *
185 * Atomically sets the value of @v to @i.
186 */
187#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
188
189#include <linux/irqflags.h>
190
191static 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)
220#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
221#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
222
223#define atomic_xchg(ptr, v) (xchg(&(ptr)->counter, (v)))
224#define atomic_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), (old), (new)))
225
226static inline int __atomic_add_unless(atomic_t *v, int a, int u)
227{
228 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;
233}
234
235#endif /* __ASM_GENERIC_ATOMIC_H */