1 /*- 2 * Copyright (c) 2005 David Xu <davidxu@freebsd.org> 3 * Copyright (c) 2005 Matthew Dillon <dillon@backplane.com> 4 * 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $DragonFly: src/lib/libthread_xu/thread/thr_umtx.c,v 1.3 2006/04/04 14:04:39 davidxu Exp $ 29 */ 30 31 #include <assert.h> 32 #include <errno.h> 33 #include <unistd.h> 34 #include <sys/time.h> 35 36 #include "thr_private.h" 37 38 /* 39 * This function is used to acquire a contested lock. 40 */ 41 int 42 __thr_umtx_lock(volatile umtx_t *mtx, int timo) 43 { 44 int v, ret = 0; 45 46 /* contested */ 47 do { 48 v = *mtx; 49 if (v == 2 || atomic_cmpset_acq_int(mtx, 1, 2)) { 50 if (timo == 0) 51 umtx_sleep(mtx, 2, timo); 52 else if (umtx_sleep(mtx, 2, timo) < 0) { 53 if (errno == EAGAIN) { 54 if (atomic_cmpset_acq_int(mtx, 0, 2)) 55 ret = 0; 56 else 57 ret = ETIMEDOUT; 58 break; 59 } 60 } 61 } 62 } while (!atomic_cmpset_acq_int(mtx, 0, 2)); 63 64 return (ret); 65 } 66 67 void 68 __thr_umtx_unlock(volatile umtx_t *mtx) 69 { 70 int v; 71 72 for (;;) { 73 v = *mtx; 74 if (atomic_cmpset_acq_int(mtx, v, v-1)) { 75 if (v != 1) { 76 *mtx = 0; 77 umtx_wakeup(mtx, 1); 78 } 79 break; 80 } 81 } 82 } 83 84 int 85 __thr_umtx_timedlock(volatile umtx_t *mtx, const struct timespec *timeout) 86 { 87 struct timespec ts, ts2, ts3; 88 int timo, ret; 89 90 if ((timeout->tv_sec < 0) || 91 (timeout->tv_sec == 0 && timeout->tv_nsec <= 0)) 92 return (ETIMEDOUT); 93 94 /* XXX there should have MONO timer! */ 95 clock_gettime(CLOCK_REALTIME, &ts); 96 TIMESPEC_ADD(&ts, &ts, timeout); 97 ts2 = *timeout; 98 99 for (;;) { 100 if (ts2.tv_nsec) { 101 timo = (int)(ts2.tv_nsec / 1000); 102 if (timo == 0) 103 timo = 1; 104 } else { 105 timo = 1000000; 106 } 107 ret = __thr_umtx_lock(mtx, timo); 108 if (ret != ETIMEDOUT) 109 break; 110 clock_gettime(CLOCK_REALTIME, &ts3); 111 TIMESPEC_SUB(&ts2, &ts, &ts3); 112 if (ts2.tv_sec < 0 || (ts2.tv_sec == 0 && ts2.tv_nsec <= 0)) { 113 ret = ETIMEDOUT; 114 break; 115 } 116 } 117 return (ret); 118 } 119 120 int 121 _thr_umtx_wait(volatile umtx_t *mtx, int exp, const struct timespec *timeout, 122 int clockid) 123 { 124 struct timespec ts, ts2, ts3; 125 int timo, ret = 0; 126 127 if (*mtx != exp) 128 return (0); 129 130 if (timeout == NULL) { 131 if (umtx_sleep(mtx, exp, 0) < 0) { 132 if (errno == EINTR) 133 ret = EINTR; 134 } 135 return (ret); 136 } 137 138 if ((timeout->tv_sec < 0) || 139 (timeout->tv_sec == 0 && timeout->tv_nsec <= 0)) 140 return (ETIMEDOUT); 141 142 clock_gettime(clockid, &ts); 143 TIMESPEC_ADD(&ts, &ts, timeout); 144 ts2 = *timeout; 145 146 for (;;) { 147 if (ts2.tv_nsec) { 148 timo = (int)(ts2.tv_nsec / 1000); 149 if (timo == 0) 150 timo = 1; 151 } else { 152 timo = 1000000; 153 } 154 if (umtx_sleep(mtx, exp, timo) < 0) { 155 if (errno == EBUSY) { 156 ret = 0; 157 break; 158 } else if (errno == EINTR) { 159 ret = EINTR; 160 break; 161 } 162 } 163 clock_gettime(clockid, &ts3); 164 TIMESPEC_SUB(&ts2, &ts, &ts3); 165 if (ts2.tv_sec < 0 || (ts2.tv_sec == 0 && ts2.tv_nsec <= 0)) { 166 ret = ETIMEDOUT; 167 break; 168 } 169 } 170 return (ret); 171 } 172 173 void _thr_umtx_wake(volatile umtx_t *mtx, int count) 174 { 175 umtx_wakeup(mtx, count); 176 } 177