1/* $NetBSD: membar_ops.S,v 1.8 2022/04/09 23:32:52 riastradh Exp $ */ 2 3/*- 4 * Copyright (c) 2007 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 by 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#include "atomic_op_asm.h" 33 34#ifdef _KERNEL_OPT 35#include "opt_multiprocessor.h" 36#endif 37 38 .text 39 40/* 41 * These assume Total Store Order (TSO), which may reorder 42 * store-before-load but nothing else. Hence, only membar_sync (and 43 * its deprecated alias membar_enter) must issue anything -- 44 * specifically, an LDSTUB, which (along with SWAP) is the only 45 * instruction that implies a sequential consistency barrier. 46 * 47 * If we ran with Partial Store Order (PSO), we would also need to 48 * issue STBAR for membar_release (load/store-before-store) and 49 * membar_producer (store-before-store). 50 */ 51 52ENTRY(_membar_acquire) 53 retl 54 nop 55END(_membar_acquire) 56ATOMIC_OP_ALIAS(membar_acquire,_membar_acquire) 57 58ENTRY(_membar_release) 59 retl 60 nop 61END(_membar_release) 62ATOMIC_OP_ALIAS(membar_release,_membar_release) 63 64ENTRY(_membar_sync) 65 retl 66#if !defined(_KERNEL) || defined(MULTIPROCESSOR) 67 ldstub [%sp - 4], %g0 68#else 69 nop 70#endif 71END(_membar_sync) 72ATOMIC_OP_ALIAS(membar_sync,_membar_sync) 73 74ATOMIC_OP_ALIAS(membar_producer,_membar_release) 75STRONG_ALIAS(_membar_producer,_membar_release) 76ATOMIC_OP_ALIAS(membar_consumer,_membar_acquire) 77STRONG_ALIAS(_membar_consumer,_membar_acquire) 78ATOMIC_OP_ALIAS(membar_enter,_membar_sync) 79STRONG_ALIAS(_membar_enter,_membar_sync) 80ATOMIC_OP_ALIAS(membar_exit,_membar_release) 81STRONG_ALIAS(_membar_exit,_membar_release) 82