atomic.h revision 329956 
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice unmodified, this list of conditions, and the following
13 *    disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: stable/11/sys/compat/linuxkpi/common/include/asm/atomic.h 329956 2018-02-25 10:21:31Z hselasky $
30 */
31
32#ifndef _ASM_ATOMIC_H_
33#define	_ASM_ATOMIC_H_
34
35#include <linux/compiler.h>
36#include <sys/types.h>
37#include <machine/atomic.h>
38
39#define	ATOMIC_INIT(x)	{ .counter = (x) }
40
41typedef struct {
42	volatile int counter;
43} atomic_t;
44
45/*------------------------------------------------------------------------*
46 *	32-bit atomic operations
47 *------------------------------------------------------------------------*/
48
49#define	atomic_add(i, v)		atomic_add_return((i), (v))
50#define	atomic_sub(i, v)		atomic_sub_return((i), (v))
51#define	atomic_inc_return(v)		atomic_add_return(1, (v))
52#define	atomic_add_negative(i, v)	(atomic_add_return((i), (v)) < 0)
53#define	atomic_add_and_test(i, v)	(atomic_add_return((i), (v)) == 0)
54#define	atomic_sub_and_test(i, v)	(atomic_sub_return((i), (v)) == 0)
55#define	atomic_dec_and_test(v)		(atomic_sub_return(1, (v)) == 0)
56#define	atomic_inc_and_test(v)		(atomic_add_return(1, (v)) == 0)
57#define	atomic_dec_return(v)		atomic_sub_return(1, (v))
58#define	atomic_inc_not_zero(v)		atomic_add_unless((v), 1, 0)
59
60static inline int
61atomic_add_return(int i, atomic_t *v)
62{
63	return i + atomic_fetchadd_int(&v->counter, i);
64}
65
66static inline int
67atomic_sub_return(int i, atomic_t *v)
68{
69	return atomic_fetchadd_int(&v->counter, -i) - i;
70}
71
72static inline void
73atomic_set(atomic_t *v, int i)
74{
75	WRITE_ONCE(v->counter, i);
76}
77
78static inline void
79atomic_set_release(atomic_t *v, int i)
80{
81	atomic_store_rel_int(&v->counter, i);
82}
83
84static inline void
85atomic_set_mask(unsigned int mask, atomic_t *v)
86{
87	atomic_set_int(&v->counter, mask);
88}
89
90static inline int
91atomic_read(const atomic_t *v)
92{
93	return READ_ONCE(v->counter);
94}
95
96static inline int
97atomic_inc(atomic_t *v)
98{
99	return atomic_fetchadd_int(&v->counter, 1) + 1;
100}
101
102static inline int
103atomic_dec(atomic_t *v)
104{
105	return atomic_fetchadd_int(&v->counter, -1) - 1;
106}
107
108static inline int
109atomic_add_unless(atomic_t *v, int a, int u)
110{
111	int c;
112
113	for (;;) {
114		c = atomic_read(v);
115		if (unlikely(c == u))
116			break;
117		if (likely(atomic_cmpset_int(&v->counter, c, c + a)))
118			break;
119	}
120	return (c != u);
121}
122
123static inline void
124atomic_clear_mask(unsigned int mask, atomic_t *v)
125{
126	atomic_clear_int(&v->counter, mask);
127}
128
129static inline int
130atomic_xchg(atomic_t *v, int i)
131{
132#if defined(__i386__) || defined(__amd64__) || \
133    defined(__arm__) || defined(__aarch64__) || \
134    defined(__powerpc__)
135	return (atomic_swap_int(&v->counter, i));
136#else
137	int ret;
138	for (;;) {
139		ret = READ_ONCE(v->counter);
140		if (atomic_cmpset_int(&v->counter, ret, i))
141			break;
142	}
143	return (ret);
144#endif
145}
146
147static inline int
148atomic_cmpxchg(atomic_t *v, int old, int new)
149{
150	int ret = old;
151
152	for (;;) {
153		if (atomic_cmpset_int(&v->counter, old, new))
154			break;
155		ret = READ_ONCE(v->counter);
156		if (ret != old)
157			break;
158	}
159	return (ret);
160}
161
162#define	cmpxchg(ptr, old, new) ({					\
163	union {								\
164		__typeof(*(ptr)) val;					\
165		u8 u8[0];						\
166		u16 u16[0];						\
167		u32 u32[0];						\
168		u64 u64[0];						\
169	} __ret = { .val = (old) }, __new = { .val = (new) };		\
170									\
171	CTASSERT(sizeof(__ret.val) == 1 || sizeof(__ret.val) == 2 ||	\
172	    sizeof(__ret.val) == 4 || sizeof(__ret.val) == 8);		\
173									\
174	switch (sizeof(__ret.val)) {					\
175	case 1:								\
176		while (!atomic_fcmpset_8((volatile u8 *)(ptr),		\
177		    __ret.u8, __new.u8[0]) && __ret.val == (old))	\
178			;						\
179		break;							\
180	case 2:								\
181		while (!atomic_fcmpset_16((volatile u16 *)(ptr),	\
182		    __ret.u16, __new.u16[0]) && __ret.val == (old))	\
183			;						\
184		break;							\
185	case 4:								\
186		while (!atomic_fcmpset_32((volatile u32 *)(ptr),	\
187		    __ret.u32, __new.u32[0]) && __ret.val == (old))	\
188			;						\
189		break;							\
190	case 8:								\
191		while (!atomic_fcmpset_64((volatile u64 *)(ptr),	\
192		    __ret.u64, __new.u64[0]) && __ret.val == (old))	\
193			;						\
194		break;							\
195	}								\
196	__ret.val;							\
197})
198
199#define	cmpxchg_relaxed(...)	cmpxchg(__VA_ARGS__)
200
201#define	xchg(ptr, v) ({						\
202	__typeof(*(ptr)) __ret;					\
203								\
204	__ret = *(ptr);						\
205	*(ptr) = v;						\
206	__ret;							\
207})
208
209#define	LINUX_ATOMIC_OP(op, c_op)				\
210static inline void atomic_##op(int i, atomic_t *v)		\
211{								\
212	int c, old;						\
213								\
214	c = v->counter;						\
215	while ((old = atomic_cmpxchg(v, c, c c_op i)) != c)	\
216		c = old;					\
217}
218
219#define	LINUX_ATOMIC_FETCH_OP(op, c_op)				\
220static inline int atomic_fetch_##op(int i, atomic_t *v)		\
221{								\
222	int c, old;						\
223								\
224	c = v->counter;						\
225	while ((old = atomic_cmpxchg(v, c, c c_op i)) != c)	\
226		c = old;					\
227								\
228	return (c);						\
229}
230
231LINUX_ATOMIC_OP(or, |)
232LINUX_ATOMIC_OP(and, &)
233LINUX_ATOMIC_OP(andnot, &~)
234LINUX_ATOMIC_OP(xor, ^)
235
236LINUX_ATOMIC_FETCH_OP(or, |)
237LINUX_ATOMIC_FETCH_OP(and, &)
238LINUX_ATOMIC_FETCH_OP(andnot, &~)
239LINUX_ATOMIC_FETCH_OP(xor, ^)
240
241#endif					/* _ASM_ATOMIC_H_ */
242