1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Berkeley Software Design Inc's name may not be used to endorse or 15 * promote products derived from this software without specific prior 16 * written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 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