1 /* $NetBSD: mutex.h,v 1.6 2009/04/24 17:49:51 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2002, 2006, 2009 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe 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 #ifndef _X86_MUTEX_H_ 33 #define _X86_MUTEX_H_ 34 35 struct kmutex { 36 union { 37 volatile uintptr_t mtxa_owner; 38 #ifdef __MUTEX_PRIVATE 39 struct { 40 volatile uint8_t mtxs_dummy; 41 ipl_cookie_t mtxs_ipl; 42 __cpu_simple_lock_t mtxs_lock; 43 volatile uint8_t mtxs_unused; 44 } s; 45 #endif 46 } u; 47 }; 48 49 #ifdef __MUTEX_PRIVATE 50 51 #define mtx_owner u.mtxa_owner 52 #define mtx_ipl u.s.mtxs_ipl 53 #define mtx_lock u.s.mtxs_lock 54 55 #define __HAVE_MUTEX_STUBS 1 56 #define __HAVE_SPIN_MUTEX_STUBS 1 57 #define __HAVE_SIMPLE_MUTEXES 1 58 59 /* 60 * MUTEX_RECEIVE: technically, no memory barrier is required 61 * as 'ret' implies a load fence. However we need this to 62 * handle a bug with some Opteron revisions. See patch.c, 63 * lock_stubs.S. 64 */ 65 #define MUTEX_RECEIVE(mtx) membar_consumer() 66 67 /* 68 * MUTEX_GIVE: no memory barrier required, as _lock_cas() will take care of it. 69 */ 70 #define MUTEX_GIVE(mtx) /* nothing */ 71 72 #define MUTEX_CAS(p, o, n) \ 73 (_atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o)) 74 75 unsigned long _atomic_cas_ulong(volatile unsigned long *, 76 unsigned long, unsigned long); 77 78 #endif /* __MUTEX_PRIVATE */ 79 80 #endif /* _X86_MUTEX_H_ */ 81