1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2003 David Xu <[email protected]>
5 * Copyright (c) 2016 The FreeBSD Foundation
6 * All rights reserved.
7 *
8 * Portions of this software were developed by Konstantin Belousov
9 * under sponsorship from the FreeBSD Foundation.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35
36 #include "namespace.h"
37 #include <errno.h>
38 #include <stdlib.h>
39 #include <pthread.h>
40 #include "un-namespace.h"
41
42 #include "thr_private.h"
43
44 _Static_assert(sizeof(struct pthread_spinlock) <= PAGE_SIZE,
45 "pthread_spinlock is too large for off-page");
46
47 #define SPIN_COUNT 100000
48
49 __weak_reference(_pthread_spin_init, pthread_spin_init);
50 __weak_reference(_pthread_spin_destroy, pthread_spin_destroy);
51 __weak_reference(_pthread_spin_trylock, pthread_spin_trylock);
52 __weak_reference(_pthread_spin_lock, pthread_spin_lock);
53 __weak_reference(_pthread_spin_unlock, pthread_spin_unlock);
54
55 int
_pthread_spin_init(pthread_spinlock_t * lock,int pshared)56 _pthread_spin_init(pthread_spinlock_t *lock, int pshared)
57 {
58 struct pthread_spinlock *lck;
59
60 if (lock == NULL)
61 return (EINVAL);
62 if (pshared == PTHREAD_PROCESS_PRIVATE) {
63 lck = malloc(sizeof(struct pthread_spinlock));
64 if (lck == NULL)
65 return (ENOMEM);
66 *lock = lck;
67 } else if (pshared == PTHREAD_PROCESS_SHARED) {
68 lck = __thr_pshared_offpage(lock, 1);
69 if (lck == NULL)
70 return (EFAULT);
71 *lock = THR_PSHARED_PTR;
72 } else {
73 return (EINVAL);
74 }
75 _thr_umutex_init(&lck->s_lock);
76 return (0);
77 }
78
79 int
_pthread_spin_destroy(pthread_spinlock_t * lock)80 _pthread_spin_destroy(pthread_spinlock_t *lock)
81 {
82 void *l;
83 int ret;
84
85 if (lock == NULL || *lock == NULL) {
86 ret = EINVAL;
87 } else if (*lock == THR_PSHARED_PTR) {
88 l = __thr_pshared_offpage(lock, 0);
89 if (l != NULL)
90 __thr_pshared_destroy(l);
91 ret = 0;
92 } else {
93 free(*lock);
94 *lock = NULL;
95 ret = 0;
96 }
97 return (ret);
98 }
99
100 int
_pthread_spin_trylock(pthread_spinlock_t * lock)101 _pthread_spin_trylock(pthread_spinlock_t *lock)
102 {
103 struct pthread_spinlock *lck;
104
105 if (lock == NULL || *lock == NULL)
106 return (EINVAL);
107 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock;
108 if (lck == NULL)
109 return (EINVAL);
110 return (THR_UMUTEX_TRYLOCK(_get_curthread(), &lck->s_lock));
111 }
112
113 int
_pthread_spin_lock(pthread_spinlock_t * lock)114 _pthread_spin_lock(pthread_spinlock_t *lock)
115 {
116 struct pthread *curthread;
117 struct pthread_spinlock *lck;
118 int count;
119
120 if (lock == NULL)
121 return (EINVAL);
122 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock;
123 if (lck == NULL)
124 return (EINVAL);
125
126 curthread = _get_curthread();
127 count = SPIN_COUNT;
128 while (THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock) != 0) {
129 while (lck->s_lock.m_owner) {
130 if (!_thr_is_smp) {
131 _pthread_yield();
132 } else {
133 CPU_SPINWAIT;
134 if (--count <= 0) {
135 count = SPIN_COUNT;
136 _pthread_yield();
137 }
138 }
139 }
140 }
141 return (0);
142 }
143
144 int
_pthread_spin_unlock(pthread_spinlock_t * lock)145 _pthread_spin_unlock(pthread_spinlock_t *lock)
146 {
147 struct pthread_spinlock *lck;
148
149 if (lock == NULL)
150 return (EINVAL);
151 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock;
152 if (lck == NULL)
153 return (EINVAL);
154 return (THR_UMUTEX_UNLOCK(_get_curthread(), &lck->s_lock));
155 }
156