membar_ops.S revision 1.8 
11.8Sriastrad/*	$NetBSD: membar_ops.S,v 1.8 2022/04/09 23:32:52 riastradh Exp $	*/
21.1Sad
31.1Sad/*-
41.1Sad * Copyright (c) 2007 The NetBSD Foundation, Inc.
51.1Sad * All rights reserved.
61.1Sad *
71.1Sad * This code is derived from software contributed to The NetBSD Foundation
81.1Sad * by Jason R. Thorpe, and by Andrew Doran.
91.1Sad *
101.1Sad * Redistribution and use in source and binary forms, with or without
111.1Sad * modification, are permitted provided that the following conditions
121.1Sad * are met:
131.1Sad * 1. Redistributions of source code must retain the above copyright
141.1Sad *    notice, this list of conditions and the following disclaimer.
151.1Sad * 2. Redistributions in binary form must reproduce the above copyright
161.1Sad *    notice, this list of conditions and the following disclaimer in the
171.1Sad *    documentation and/or other materials provided with the distribution.
181.5Sriastrad *
191.1Sad * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
201.1Sad * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
211.1Sad * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
221.1Sad * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
231.1Sad * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
241.1Sad * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
251.1Sad * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
261.1Sad * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
271.1Sad * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
281.1Sad * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
291.1Sad * POSSIBILITY OF SUCH DAMAGE.
301.1Sad */
311.1Sad
321.1Sad#include "atomic_op_asm.h"
331.1Sad
341.6Sriastrad#ifdef _KERNEL_OPT
351.6Sriastrad#include "opt_multiprocessor.h"
361.6Sriastrad#endif
371.6Sriastrad
381.1Sad	.text
391.1Sad
401.6Sriastrad/*
411.6Sriastrad * These assume Total Store Order (TSO), which may reorder
421.7Sriastrad * store-before-load but nothing else.  Hence, only membar_sync (and
431.7Sriastrad * its deprecated alias membar_enter) must issue anything --
441.7Sriastrad * specifically, an LDSTUB, which (along with SWAP) is the only
451.7Sriastrad * instruction that implies a sequential consistency barrier.
461.6Sriastrad *
471.6Sriastrad * If we ran with Partial Store Order (PSO), we would also need to
481.8Sriastrad * issue STBAR for membar_release (load/store-before-store) and
491.6Sriastrad * membar_producer (store-before-store).
501.6Sriastrad */
511.1Sad
521.8SriastradENTRY(_membar_acquire)
531.1Sad	retl
541.1Sad	 nop
551.8SriastradEND(_membar_acquire)
561.8SriastradATOMIC_OP_ALIAS(membar_acquire,_membar_acquire)
571.8Sriastrad
581.8SriastradENTRY(_membar_release)
591.8Sriastrad	retl
601.8Sriastrad	 nop
611.8SriastradEND(_membar_release)
621.8SriastradATOMIC_OP_ALIAS(membar_release,_membar_release)
631.1Sad
641.6SriastradENTRY(_membar_sync)
651.1Sad	retl
661.6Sriastrad#if !defined(_KERNEL) || defined(MULTIPROCESSOR)
671.6Sriastrad	 ldstub	[%sp - 4], %g0
681.6Sriastrad#else
691.6Sriastrad	 nop
701.6Sriastrad#endif
711.6SriastradEND(_membar_sync)
721.8SriastradATOMIC_OP_ALIAS(membar_sync,_membar_sync)
731.1Sad
741.8SriastradATOMIC_OP_ALIAS(membar_producer,_membar_release)
751.8SriastradSTRONG_ALIAS(_membar_producer,_membar_release)
761.8SriastradATOMIC_OP_ALIAS(membar_consumer,_membar_acquire)
771.8SriastradSTRONG_ALIAS(_membar_consumer,_membar_acquire)
781.7SriastradATOMIC_OP_ALIAS(membar_enter,_membar_sync)
791.7SriastradSTRONG_ALIAS(_membar_enter,_membar_sync)
801.8SriastradATOMIC_OP_ALIAS(membar_exit,_membar_release)
811.8SriastradSTRONG_ALIAS(_membar_exit,_membar_release)
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