1 /*
2  * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/param.h>
28 #include <sys/lock.h>
29 #include <sys/mutex.h>
30 #include <sys/atomic.h>
31 
32 #if !defined(__LP64__) && !defined(__mips_n32) && \
33 	!defined(ARM_HAVE_ATOMIC64) && !defined(I386_HAVE_ATOMIC64) && \
34 	!defined(HAS_EMULATED_ATOMIC64)
35 
36 #ifdef _KERNEL
37 #include <sys/kernel.h>
38 
39 struct mtx atomic_mtx;
40 MTX_SYSINIT(atomic, &atomic_mtx, "atomic", MTX_DEF);
41 #else
42 #include <pthread.h>
43 
44 #define	mtx_lock(lock)		pthread_mutex_lock(lock)
45 #define	mtx_unlock(lock)	pthread_mutex_unlock(lock)
46 
47 static pthread_mutex_t atomic_mtx;
48 
49 static __attribute__((constructor)) void
50 atomic_init(void)
51 {
52 	pthread_mutex_init(&atomic_mtx, NULL);
53 }
54 #endif
55 
56 void
57 atomic_add_64(volatile uint64_t *target, int64_t delta)
58 {
59 
60 	mtx_lock(&atomic_mtx);
61 	*target += delta;
62 	mtx_unlock(&atomic_mtx);
63 }
64 
65 void
66 atomic_dec_64(volatile uint64_t *target)
67 {
68 
69 	mtx_lock(&atomic_mtx);
70 	*target -= 1;
71 	mtx_unlock(&atomic_mtx);
72 }
73 
74 uint64_t
75 atomic_swap_64(volatile uint64_t *a, uint64_t value)
76 {
77 	uint64_t ret;
78 
79 	mtx_lock(&atomic_mtx);
80 	ret = *a;
81 	*a = value;
82 	mtx_unlock(&atomic_mtx);
83 	return (ret);
84 }
85 
86 uint64_t
87 atomic_load_64(volatile uint64_t *a)
88 {
89 	uint64_t ret;
90 
91 	mtx_lock(&atomic_mtx);
92 	ret = *a;
93 	mtx_unlock(&atomic_mtx);
94 	return (ret);
95 }
96 
97 uint64_t
98 atomic_add_64_nv(volatile uint64_t *target, int64_t delta)
99 {
100 	uint64_t newval;
101 
102 	mtx_lock(&atomic_mtx);
103 	newval = (*target += delta);
104 	mtx_unlock(&atomic_mtx);
105 	return (newval);
106 }
107 
108 uint64_t
109 atomic_cas_64(volatile uint64_t *target, uint64_t cmp, uint64_t newval)
110 {
111 	uint64_t oldval;
112 
113 	mtx_lock(&atomic_mtx);
114 	oldval = *target;
115 	if (oldval == cmp)
116 		*target = newval;
117 	mtx_unlock(&atomic_mtx);
118 	return (oldval);
119 }
120 #endif
121