1 /* $OpenBSD: synch.h,v 1.1 2017/08/15 06:13:24 guenther Exp $ */ 2 /* 3 * Copyright (c) 2017 Martin Pieuchot 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18 #include <sys/atomic.h> 19 #include <sys/time.h> 20 #include <sys/futex.h> 21 22 REDIRECT_SYSCALL(futex); 23 24 static inline int 25 _wake(volatile uint32_t *p, int n) 26 { 27 return futex(p, FUTEX_WAKE, n, NULL, NULL); 28 } 29 30 static inline void 31 _wait(volatile uint32_t *p, int val) 32 { 33 while (*p != (uint32_t)val) 34 futex(p, FUTEX_WAIT, val, NULL, NULL); 35 } 36 37 static inline int 38 _twait(volatile uint32_t *p, int val, clockid_t clockid, const struct timespec *abs) 39 { 40 struct timespec rel; 41 42 if (abs == NULL) 43 return futex(p, FUTEX_WAIT, val, NULL, NULL); 44 45 if (abs->tv_nsec >= 1000000000 || clock_gettime(clockid, &rel)) 46 return (EINVAL); 47 48 rel.tv_sec = abs->tv_sec - rel.tv_sec; 49 if ((rel.tv_nsec = abs->tv_nsec - rel.tv_nsec) < 0) { 50 rel.tv_sec--; 51 rel.tv_nsec += 1000000000; 52 } 53 if (rel.tv_sec < 0) 54 return (ETIMEDOUT); 55 56 return futex(p, FUTEX_WAIT, val, &rel, NULL); 57 } 58 59 static inline int 60 _requeue(volatile uint32_t *p, int n, int m, volatile uint32_t *q) 61 { 62 return futex(p, FUTEX_REQUEUE, n, (void *)(long)m, q); 63 } 64