1 /*
2 * Copyright © 2015 Intel
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24 #ifndef UTIL_FUTEX_H
25 #define UTIL_FUTEX_H
26
27 #if defined(HAVE_LINUX_FUTEX_H)
28 #define UTIL_FUTEX_SUPPORTED 1
29
30 #include <limits.h>
31 #include <stdint.h>
32 #include <unistd.h>
33 #include <linux/futex.h>
34 #include <sys/syscall.h>
35 #include <sys/time.h>
36
37 #ifndef SYS_futex
38 #define SYS_futex SYS_futex_time64
39 #endif
40
sys_futex(void * addr1,int op,int val1,const struct timespec * timeout,void * addr2,int val3)41 static inline long sys_futex(void *addr1, int op, int val1, const struct timespec *timeout, void *addr2, int val3)
42 {
43 return syscall(SYS_futex, addr1, op, val1, timeout, addr2, val3);
44 }
45
futex_wake(uint32_t * addr,int count)46 static inline int futex_wake(uint32_t *addr, int count)
47 {
48 return sys_futex(addr, FUTEX_WAKE, count, NULL, NULL, 0);
49 }
50
futex_wait(uint32_t * addr,int32_t value,const struct timespec * timeout)51 static inline int futex_wait(uint32_t *addr, int32_t value, const struct timespec *timeout)
52 {
53 /* FUTEX_WAIT_BITSET with FUTEX_BITSET_MATCH_ANY is equivalent to
54 * FUTEX_WAIT, except that it treats the timeout as absolute. */
55 return sys_futex(addr, FUTEX_WAIT_BITSET, value, timeout, NULL,
56 FUTEX_BITSET_MATCH_ANY);
57 }
58
59 #elif defined(__FreeBSD__)
60 #define UTIL_FUTEX_SUPPORTED 1
61
62 #include <assert.h>
63 #include <errno.h>
64 #include <fcntl.h>
65 #include <sys/types.h>
66 #include <sys/umtx.h>
67 #include <sys/time.h>
68
futex_wake(uint32_t * addr,int count)69 static inline int futex_wake(uint32_t *addr, int count)
70 {
71 assert(count == (int)(uint32_t)count); /* Check that bits weren't discarded */
72 return _umtx_op(addr, UMTX_OP_WAKE, (uint32_t)count, NULL, NULL) == -1 ? errno : 0;
73 }
74
futex_wait(uint32_t * addr,int32_t value,struct timespec * timeout)75 static inline int futex_wait(uint32_t *addr, int32_t value, struct timespec *timeout)
76 {
77 void *uaddr = NULL, *uaddr2 = NULL;
78 struct _umtx_time tmo = {
79 ._flags = UMTX_ABSTIME,
80 ._clockid = CLOCK_MONOTONIC
81 };
82
83 assert(value == (int)(uint32_t)value); /* Check that bits weren't discarded */
84
85 if (timeout != NULL) {
86 tmo._timeout = *timeout;
87 uaddr = (void *)(uintptr_t)sizeof(tmo);
88 uaddr2 = (void *)&tmo;
89 }
90
91 return _umtx_op(addr, UMTX_OP_WAIT_UINT, (uint32_t)value, uaddr, uaddr2) == -1 ? errno : 0;
92 }
93
94 #elif defined(__OpenBSD__)
95 #define UTIL_FUTEX_SUPPORTED 1
96
97 #include <sys/time.h>
98 #include <sys/futex.h>
99
futex_wake(uint32_t * addr,int count)100 static inline int futex_wake(uint32_t *addr, int count)
101 {
102 return futex(addr, FUTEX_WAKE, count, NULL, NULL);
103 }
104
futex_wait(uint32_t * addr,int32_t value,const struct timespec * timeout)105 static inline int futex_wait(uint32_t *addr, int32_t value, const struct timespec *timeout)
106 {
107 struct timespec tsnow, tsrel;
108
109 if (timeout == NULL)
110 return futex(addr, FUTEX_WAIT, value, NULL, NULL);
111
112 clock_gettime(CLOCK_MONOTONIC, &tsnow);
113 if (timespeccmp(&tsnow, timeout, <))
114 timespecsub(timeout, &tsnow, &tsrel);
115 else
116 timespecclear(&tsrel);
117 return futex(addr, FUTEX_WAIT, value, &tsrel, NULL);
118 }
119
120 #elif defined(_WIN32) && !defined(WINDOWS_NO_FUTEX)
121 #define UTIL_FUTEX_SUPPORTED 1
122
123 #include <windows.h>
124 #include <stdint.h>
125 #include <c11/time.h>
126 #include <assert.h>
127 #include <errno.h>
128
futex_wake(uint32_t * addr,int count)129 static inline int futex_wake(uint32_t *addr, int count)
130 {
131 /* All current callers fall into one of these buckets, and we'll get the semantics
132 * wrong if someone tries to be more clever.
133 */
134 assert(count == 1 || count == INT_MAX);
135 if (count == 1)
136 WakeByAddressSingle(addr);
137 else
138 WakeByAddressAll(addr);
139 return count;
140 }
141
futex_wait(uint32_t * addr,int32_t value,const struct timespec * timeout)142 static inline int futex_wait(uint32_t *addr, int32_t value, const struct timespec *timeout)
143 {
144 DWORD timeout_ms = INFINITE;
145 if (timeout != NULL) {
146 struct timespec tsnow;
147 timespec_get(&tsnow, TIME_UTC);
148
149 timeout_ms = (timeout->tv_sec - tsnow.tv_nsec) * 1000 +
150 (timeout->tv_nsec - tsnow.tv_nsec) / 1000000;
151 }
152
153 if (WaitOnAddress(addr, &value, sizeof(value), timeout_ms))
154 return 0;
155 return GetLastError() == ERROR_TIMEOUT ? ETIMEDOUT : -1;
156 }
157
158 #else
159 #define UTIL_FUTEX_SUPPORTED 0
160 #endif
161
162 #endif /* UTIL_FUTEX_H */
163