1 /*- 2 * Copyright (c) 2005 David Xu <davidxu@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 */ 27 28 #ifndef _THR_DFLY_UMTX_H_ 29 #define _THR_DFLY_UMTX_H_ 30 31 #include <unistd.h> 32 33 #define UMTX_LOCKED 1 34 #define UMTX_CONTESTED 2 35 36 #define cpu_pause() __asm __volatile("pause":::"memory") 37 38 typedef int umtx_t; 39 40 int __thr_umtx_lock(volatile umtx_t *mtx, int id, int timo); 41 int __thr_umtx_timedlock(volatile umtx_t *mtx, int id, 42 const struct timespec *timeout); 43 void __thr_umtx_unlock(volatile umtx_t *mtx, int v, int id); 44 45 static inline void 46 _thr_umtx_init(volatile umtx_t *mtx) 47 { 48 *mtx = 0; 49 } 50 51 static inline int 52 _thr_umtx_trylock(volatile umtx_t *mtx, int id) 53 { 54 if (atomic_cmpset_acq_int(mtx, 0, id)) 55 return (0); 56 cpu_pause(); 57 if (atomic_cmpset_acq_int(mtx, 0, id)) 58 return (0); 59 cpu_pause(); 60 if (atomic_cmpset_acq_int(mtx, 0, id)) 61 return (0); 62 return (EBUSY); 63 } 64 65 static inline int 66 _thr_umtx_lock(volatile umtx_t *mtx, int id) 67 { 68 if (atomic_cmpset_acq_int(mtx, 0, id)) 69 return (0); 70 return (__thr_umtx_lock(mtx, id, 0)); 71 } 72 73 static inline int 74 _thr_umtx_timedlock(volatile umtx_t *mtx, int id, 75 const struct timespec *timeout) 76 { 77 if (atomic_cmpset_acq_int(mtx, 0, id)) { 78 return (0); 79 } 80 return (__thr_umtx_timedlock(mtx, id, timeout)); 81 } 82 83 static inline void 84 _thr_umtx_unlock(volatile umtx_t *mtx, int id) 85 { 86 int v; 87 88 v = atomic_swap_int(mtx, 0); 89 if (v != id) 90 __thr_umtx_unlock(mtx, v, id); 91 } 92 93 int _thr_umtx_wait(volatile umtx_t *mtx, umtx_t exp, 94 const struct timespec *timeout, int clockid); 95 int _thr_umtx_wait_intr(volatile umtx_t *mtx, umtx_t exp); 96 void _thr_umtx_wake(volatile umtx_t *mtx, int count); 97 #endif 98