1 /* $NetBSD: barrier.h,v 1.5 2020/10/16 22:39:21 jmcneill Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell. 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 _ASM_BARRIER_H_ 33 #define _ASM_BARRIER_H_ 34 35 #include <sys/atomic.h> 36 37 #ifdef _KERNEL_OPT 38 #include "opt_multiprocessor.h" 39 #else 40 #define MULTIPROCESSOR 1 /* safer to assume multiprocessor */ 41 #endif 42 43 #if defined(__aarch64__) 44 #define mb() __asm __volatile ("dsb sy" ::: "memory") 45 #define wmb() __asm __volatile ("dsb st" ::: "memory") 46 #define rmb() __asm __volatile ("dsb ld" ::: "memory") 47 #else 48 #define mb membar_sync 49 #define wmb membar_producer 50 #define rmb membar_consumer 51 #endif 52 53 #ifdef __alpha__ /* XXX As if... */ 54 # define read_barrier_depends membar_sync 55 #else 56 # define read_barrier_depends() do {} while (0) 57 #endif 58 59 #ifdef MULTIPROCESSOR 60 # define smp_mb membar_sync 61 # define smp_wmb membar_producer 62 # define smp_rmb membar_consumer 63 # define smp_read_barrier_depends read_barrier_depends 64 #else 65 # define smp_mb() do {} while (0) 66 # define smp_wmb() do {} while (0) 67 # define smp_rmb() do {} while (0) 68 # define smp_read_barrier_depends() do {} while (0) 69 #endif 70 71 #endif /* _ASM_BARRIER_H_ */ 72