11.10Sriastrad/*	$NetBSD: membar_ops.S,v 1.10 2025/09/06 02:53:21 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.
181.6Sriastrad *
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
341.1Sad	.text
351.1Sad
361.7Sriastrad/*
371.7Sriastrad * These assume Total Store Order (TSO), which may reorder
381.8Sriastrad * store-before-load but nothing else.  Hence, only membar_sync (and
391.8Sriastrad * its deprecated alias membar_enter) must issue anything -- namely,
401.8Sriastrad * membar #StoreLoad.
411.7Sriastrad *
421.7Sriastrad * If we ran with Partial Store Order (PSO), we would also need to
431.7Sriastrad * issue membar #StoreStore for membar_exit (load/store-before-store)
441.7Sriastrad * and membar_producer (store-before-store).
451.7Sriastrad */
461.1Sad
471.9SriastradENTRY(_membar_acquire)
481.1Sad	retl
491.1Sad	 nop
501.9SriastradEND(_membar_acquire)
511.9SriastradATOMIC_OP_ALIAS(membar_acquire,_membar_acquire)
521.9Sriastrad
531.9SriastradENTRY(_membar_release)
541.9Sriastrad	retl
551.9Sriastrad	 nop
561.9SriastradEND(_membar_release)
571.9SriastradATOMIC_OP_ALIAS(membar_release,_membar_release)
581.1Sad
591.7SriastradENTRY(_membar_sync)
601.7Sriastrad	/*
611.7Sriastrad	 * Some SPARC CPUs have errata with MEMBAR in the delay slot of
621.7Sriastrad	 * a branch, such as the UltraSPARC-IIi:
631.7Sriastrad	 *
641.7Sriastrad	 *	`Apparently, the deadlock is most easily caused if the
651.7Sriastrad	 *	 delay slot of the JMPL is a MEMBAR #Sync, or any
661.7Sriastrad	 *	 instruction that synchronizes on the load or store
671.7Sriastrad	 *	 buffers being empty.'
681.7Sriastrad	 *
691.7Sriastrad	 *	UltraSPARC-IIi User's Manual, Part No. 805-0087-01, Sun
701.7Sriastrad	 *	Microsystems, October 1997, Appendix K.2 `Errata
711.7Sriastrad	 *	Created by UltraSPARC-I', Erratum 51, p. 476.
721.7Sriastrad	 *	https://www.oracle.com/technetwork/server-storage/sun-sparc-enterprise/documentation/sparc-2i-usersmanual-2516677.pdf#page=518
731.7Sriastrad	 *
741.7Sriastrad	 * So let's avoid doing that.
751.10Sriastrad	 *
761.10Sriastrad	 * Sync with paravirt_membar_sync in
771.10Sriastrad	 * sys/arch/sparc64/sparc64/locore.s.
781.7Sriastrad	 */
791.7Sriastrad	membar	#StoreLoad
801.1Sad	retl
811.3Sad	 nop
821.7SriastradEND(_membar_sync)
831.9SriastradATOMIC_OP_ALIAS(membar_sync,_membar_sync)
841.1Sad
851.9SriastradATOMIC_OP_ALIAS(membar_producer,_membar_release)
861.9SriastradSTRONG_ALIAS(_membar_producer,_membar_release)
871.9SriastradATOMIC_OP_ALIAS(membar_consumer,_membar_acquire)
881.9SriastradSTRONG_ALIAS(_membar_consumer,_membar_acquire)
891.8SriastradATOMIC_OP_ALIAS(membar_enter,_membar_sync)
901.8SriastradSTRONG_ALIAS(_membar_enter,_membar_sync)
911.9SriastradATOMIC_OP_ALIAS(membar_exit,_membar_release)
921.9SriastradSTRONG_ALIAS(_membar_exit,_membar_release)
93