1 /*- 2 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Berkeley Software Design Inc's name may not be used to endorse or 13 * promote products derived from this software without specific prior 14 * written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``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 BERKELEY SOFTWARE DESIGN INC 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 * $FreeBSD$ 29 */ 30 31 #ifndef _SYS__MUTEX_H_ 32 #define _SYS__MUTEX_H_ 33 34 #include <machine/param.h> 35 36 /* 37 * Sleep/spin mutex. 38 * 39 * All mutex implementations must always have a member called mtx_lock. 40 * Other locking primitive structures are not allowed to use this name 41 * for their members. 42 * If this rule needs to change, the bits in the mutex implementation must 43 * be modified appropriately. 44 */ 45 struct mtx { 46 struct lock_object lock_object; /* Common lock properties. */ 47 volatile uintptr_t mtx_lock; /* Owner and flags. */ 48 }; 49 50 /* 51 * Members of struct mtx_padalign must mirror members of struct mtx. 52 * mtx_padalign mutexes can use the mtx(9) API transparently without 53 * modification. 54 * Pad-aligned mutexes used within structures should generally be the 55 * first member of the struct. Otherwise, the compiler can generate 56 * additional padding for the struct to keep a correct alignment for 57 * the mutex. 58 */ 59 struct mtx_padalign { 60 struct lock_object lock_object; /* Common lock properties. */ 61 volatile uintptr_t mtx_lock; /* Owner and flags. */ 62 } __aligned(CACHE_LINE_SIZE); 63 64 #endif /* !_SYS__MUTEX_H_ */ 65