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/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include <sys/param.h>
31 #include <sys/lock.h>
32 #include <sys/mutex.h>
33 #include <sys/atomic.h>
34 
35 #if !defined(__LP64__) && !defined(__mips_n32) && \
36     !defined(ARM_HAVE_ATOMIC64) && !defined(I386_HAVE_ATOMIC64) && \
37     !defined(HAS_EMULATED_ATOMIC64)
38 
39 #ifdef _KERNEL
40 #include <sys/kernel.h>
41 
42 struct mtx atomic_mtx;
43 MTX_SYSINIT(atomic, &atomic_mtx, "atomic", MTX_DEF);
44 #else
45 #include <pthread.h>
46 
47 #define	mtx_lock(lock)		pthread_mutex_lock(lock)
48 #define	mtx_unlock(lock)	pthread_mutex_unlock(lock)
49 
50 static pthread_mutex_t atomic_mtx;
51 
52 static __attribute__((constructor)) void
53 atomic_init(void)
54 {
55 	pthread_mutex_init(&atomic_mtx, NULL);
56 }
57 #endif
58 
59 void
60 atomic_add_64(volatile uint64_t *target, int64_t delta)
61 {
62 
63 	mtx_lock(&atomic_mtx);
64 	*target += delta;
65 	mtx_unlock(&atomic_mtx);
66 }
67 
68 void
69 atomic_dec_64(volatile uint64_t *target)
70 {
71 
72 	mtx_lock(&atomic_mtx);
73 	*target -= 1;
74 	mtx_unlock(&atomic_mtx);
75 }
76 
77 uint64_t
78 atomic_swap_64(volatile uint64_t *a, uint64_t value)
79 {
80 	uint64_t ret;
81 
82 	mtx_lock(&atomic_mtx);
83 	ret = *a;
84 	*a = value;
85 	mtx_unlock(&atomic_mtx);
86 	return (ret);
87 }
88 
89 uint64_t
90 atomic_load_64(volatile uint64_t *a)
91 {
92 	uint64_t ret;
93 
94 	mtx_lock(&atomic_mtx);
95 	ret = *a;
96 	mtx_unlock(&atomic_mtx);
97 	return (ret);
98 }
99 
100 uint64_t
101 atomic_add_64_nv(volatile uint64_t *target, int64_t delta)
102 {
103 	uint64_t newval;
104 
105 	mtx_lock(&atomic_mtx);
106 	newval = (*target += delta);
107 	mtx_unlock(&atomic_mtx);
108 	return (newval);
109 }
110 
111 uint64_t
112 atomic_cas_64(volatile uint64_t *target, uint64_t cmp, uint64_t newval)
113 {
114 	uint64_t oldval;
115 
116 	mtx_lock(&atomic_mtx);
117 	oldval = *target;
118 	if (oldval == cmp)
119 		*target = newval;
120 	mtx_unlock(&atomic_mtx);
121 	return (oldval);
122 }
123 #endif
124