1 /*-
2 * Copyright (c) 2003 David Xu <davidxu@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 AUTHOR 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 AUTHOR 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
28 #include "namespace.h"
29 #include <machine/tls.h>
30 #include <errno.h>
31 #include <stdlib.h>
32 #include <pthread.h>
33 #include <pthread_np.h>
34 #include "un-namespace.h"
35
36 #include "thr_private.h"
37
38 #define SPIN_COUNT 100000
39
40 int
_pthread_spin_init(pthread_spinlock_t * lock,int pshared)41 _pthread_spin_init(pthread_spinlock_t *lock, int pshared)
42 {
43 pthread_spinlock_t lck;
44
45 if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE)
46 return (EINVAL);
47 lck = __malloc(sizeof(struct __pthread_spinlock_s));
48 if (lck == NULL)
49 return (ENOMEM);
50 _thr_umtx_init(&lck->s_lock);
51 *lock = lck;
52
53 return (0);
54 }
55
56 int
_pthread_spin_destroy(pthread_spinlock_t * lock)57 _pthread_spin_destroy(pthread_spinlock_t *lock)
58 {
59 int ret;
60
61 if (lock == NULL || *lock == NULL) {
62 ret = EINVAL;
63 } else {
64 __free(*lock);
65 *lock = NULL;
66 ret = 0;
67 }
68
69 return (ret);
70 }
71
72 int
_pthread_spin_trylock(pthread_spinlock_t * lock)73 _pthread_spin_trylock(pthread_spinlock_t *lock)
74 {
75 pthread_t curthread = tls_get_curthread();
76 pthread_spinlock_t lck;
77
78 if (lock == NULL || (lck = *lock) == NULL)
79 return (EINVAL);
80 return (THR_UMTX_TRYLOCK_PERSIST(curthread, &lck->s_lock));
81 }
82
83 int
_pthread_spin_lock(pthread_spinlock_t * lock)84 _pthread_spin_lock(pthread_spinlock_t *lock)
85 {
86 pthread_t curthread;
87 pthread_spinlock_t lck;
88 int count;
89
90 if (lock == NULL || (lck = *lock) == NULL)
91 return (EINVAL);
92
93 curthread = tls_get_curthread();
94 count = SPIN_COUNT;
95 while (THR_UMTX_TRYLOCK_PERSIST(curthread, &lck->s_lock) != 0) {
96 while (lck->s_lock) {
97 CPU_SPINWAIT; /* tell cpu we are spinning */
98 if (--count <= 0) {
99 count = SPIN_COUNT;
100 _pthread_yield();
101 }
102 }
103 }
104 return (0);
105 }
106
107 int
_pthread_spin_unlock(pthread_spinlock_t * lock)108 _pthread_spin_unlock(pthread_spinlock_t *lock)
109 {
110 pthread_t curthread = tls_get_curthread();
111 pthread_spinlock_t lck;
112
113 if (lock == NULL || (lck = *lock) == NULL)
114 return (EINVAL);
115 /* XXX: shouldn't return status? */
116 THR_UMTX_UNLOCK_PERSIST(curthread, &lck->s_lock);
117 return (0);
118 }
119
120 __strong_reference(_pthread_spin_init, pthread_spin_init);
121 __strong_reference(_pthread_spin_destroy, pthread_spin_destroy);
122 __strong_reference(_pthread_spin_trylock, pthread_spin_trylock);
123 __strong_reference(_pthread_spin_lock, pthread_spin_lock);
124 __strong_reference(_pthread_spin_unlock, pthread_spin_unlock);
125