1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2003 David Xu <davidxu@freebsd.org>
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 "namespace.h"
34 #include <errno.h>
35 #include <stdlib.h>
36 #include <pthread.h>
37 #include "un-namespace.h"
38
39 #include "thr_private.h"
40
41 _Static_assert(sizeof(struct pthread_spinlock) <= THR_PAGE_SIZE_MIN,
42 "pthread_spinlock is too large for off-page");
43
44 #define SPIN_COUNT 100000
45
46 __weak_reference(_pthread_spin_init, pthread_spin_init);
47 __weak_reference(_pthread_spin_destroy, pthread_spin_destroy);
48 __weak_reference(_pthread_spin_trylock, pthread_spin_trylock);
49 __weak_reference(_pthread_spin_lock, pthread_spin_lock);
50 __weak_reference(_pthread_spin_unlock, pthread_spin_unlock);
51
52 int
_pthread_spin_init(pthread_spinlock_t * lock,int pshared)53 _pthread_spin_init(pthread_spinlock_t *lock, int pshared)
54 {
55 struct pthread_spinlock *lck;
56
57 if (lock == NULL)
58 return (EINVAL);
59 if (pshared == PTHREAD_PROCESS_PRIVATE) {
60 lck = aligned_alloc(CACHE_LINE_SIZE,
61 roundup(sizeof(struct pthread_spinlock), CACHE_LINE_SIZE));
62 if (lck == NULL)
63 return (ENOMEM);
64 *lock = lck;
65 } else if (pshared == PTHREAD_PROCESS_SHARED) {
66 lck = __thr_pshared_offpage(lock, 1);
67 if (lck == NULL)
68 return (EFAULT);
69 *lock = THR_PSHARED_PTR;
70 } else {
71 return (EINVAL);
72 }
73 _thr_umutex_init(&lck->s_lock);
74 return (0);
75 }
76
77 int
_pthread_spin_destroy(pthread_spinlock_t * lock)78 _pthread_spin_destroy(pthread_spinlock_t *lock)
79 {
80 void *l;
81 int ret;
82
83 if (lock == NULL || *lock == NULL) {
84 ret = EINVAL;
85 } else if (*lock == THR_PSHARED_PTR) {
86 l = __thr_pshared_offpage(lock, 0);
87 if (l != NULL)
88 __thr_pshared_destroy(l);
89 ret = 0;
90 } else {
91 free(*lock);
92 *lock = NULL;
93 ret = 0;
94 }
95 return (ret);
96 }
97
98 int
_pthread_spin_trylock(pthread_spinlock_t * lock)99 _pthread_spin_trylock(pthread_spinlock_t *lock)
100 {
101 struct pthread_spinlock *lck;
102
103 if (lock == NULL || *lock == NULL)
104 return (EINVAL);
105 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock;
106 if (lck == NULL)
107 return (EINVAL);
108 return (THR_UMUTEX_TRYLOCK(_get_curthread(), &lck->s_lock));
109 }
110
111 int
_pthread_spin_lock(pthread_spinlock_t * lock)112 _pthread_spin_lock(pthread_spinlock_t *lock)
113 {
114 struct pthread *curthread;
115 struct pthread_spinlock *lck;
116 int count;
117
118 if (lock == NULL)
119 return (EINVAL);
120 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock;
121 if (lck == NULL)
122 return (EINVAL);
123
124 curthread = _get_curthread();
125 count = SPIN_COUNT;
126 while (THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock) != 0) {
127 while (lck->s_lock.m_owner) {
128 if (!_thr_is_smp) {
129 _pthread_yield();
130 } else {
131 CPU_SPINWAIT;
132 if (--count <= 0) {
133 count = SPIN_COUNT;
134 _pthread_yield();
135 }
136 }
137 }
138 }
139 return (0);
140 }
141
142 int
_pthread_spin_unlock(pthread_spinlock_t * lock)143 _pthread_spin_unlock(pthread_spinlock_t *lock)
144 {
145 struct pthread_spinlock *lck;
146
147 if (lock == NULL)
148 return (EINVAL);
149 lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock;
150 if (lck == NULL)
151 return (EINVAL);
152 return (THR_UMUTEX_UNLOCK(_get_curthread(), &lck->s_lock));
153 }
154