1 /* $NetBSD: pthread_spin.c,v 1.11 2023/05/25 14:30:03 riastradh Exp $ */
2
3 /*-
4 * Copyright (c) 2001, 2006, 2007 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Nathan J. Williams and Andrew Doran.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 /*
33 * Public (POSIX-specified) spinlocks.
34 */
35
36 #include <sys/cdefs.h>
37 __RCSID("$NetBSD: pthread_spin.c,v 1.11 2023/05/25 14:30:03 riastradh Exp $");
38
39 /* Need to use libc-private names for atomic operations. */
40 #include "../../common/lib/libc/atomic/atomic_op_namespace.h"
41
42 #include <sys/types.h>
43 #include <sys/ras.h>
44
45 #include <machine/lock.h>
46
47 #include <errno.h>
48 #include <unistd.h>
49 #include <stdio.h>
50 #include <stdlib.h>
51
52 #include "pthread.h"
53 #include "pthread_int.h"
54
55 int
pthread_spin_init(pthread_spinlock_t * lock,int pshared)56 pthread_spin_init(pthread_spinlock_t *lock, int pshared)
57 {
58
59 pthread__error(EINVAL, "Invalid pshared",
60 pshared == PTHREAD_PROCESS_PRIVATE ||
61 pshared == PTHREAD_PROCESS_SHARED);
62
63 lock->pts_magic = _PT_SPINLOCK_MAGIC;
64
65 /*
66 * We don't actually use the pshared flag for anything;
67 * CPU simple locks have all the process-shared properties
68 * that we want anyway.
69 */
70 lock->pts_flags = pshared;
71 pthread_lockinit(&lock->pts_spin);
72
73 return 0;
74 }
75
76 int
pthread_spin_destroy(pthread_spinlock_t * lock)77 pthread_spin_destroy(pthread_spinlock_t *lock)
78 {
79
80 pthread__error(EINVAL, "Invalid spinlock",
81 lock->pts_magic == _PT_SPINLOCK_MAGIC);
82
83 if (!__SIMPLELOCK_UNLOCKED_P(&lock->pts_spin))
84 return EBUSY;
85
86 lock->pts_magic = _PT_SPINLOCK_DEAD;
87
88 return 0;
89 }
90
91 int
pthread_spin_lock(pthread_spinlock_t * lock)92 pthread_spin_lock(pthread_spinlock_t *lock)
93 {
94 pthread_t self;
95
96 pthread__error(EINVAL, "Invalid spinlock",
97 lock->pts_magic == _PT_SPINLOCK_MAGIC);
98
99 self = pthread__self();
100 while (pthread__spintrylock(self, &lock->pts_spin) == 0) {
101 pthread__smt_wait();
102 }
103
104 return 0;
105 }
106
107 int
pthread_spin_trylock(pthread_spinlock_t * lock)108 pthread_spin_trylock(pthread_spinlock_t *lock)
109 {
110 pthread_t self;
111
112 pthread__error(EINVAL, "Invalid spinlock",
113 lock->pts_magic == _PT_SPINLOCK_MAGIC);
114
115 self = pthread__self();
116 if (pthread__spintrylock(self, &lock->pts_spin) == 0)
117 return EBUSY;
118 return 0;
119 }
120
121 int
pthread_spin_unlock(pthread_spinlock_t * lock)122 pthread_spin_unlock(pthread_spinlock_t *lock)
123 {
124 pthread_t self;
125
126 pthread__error(EINVAL, "Invalid spinlock",
127 lock->pts_magic == _PT_SPINLOCK_MAGIC);
128
129 self = pthread__self();
130 pthread__spinunlock(self, &lock->pts_spin);
131 pthread__smt_wake();
132
133 return 0;
134 }
135