11.13Sriastrad/*	$NetBSD: lock_stubs.s,v 1.13 2023/02/20 13:30:36 riastradh Exp $	*/
21.2Sad
31.2Sad/*-
41.2Sad * Copyright (c) 2002, 2006 The NetBSD Foundation, Inc.
51.2Sad * All rights reserved.
61.2Sad *
71.2Sad * This code is derived from software contributed to The NetBSD Foundation
81.2Sad * by Jason R. Thorpe and Andrew Doran.
91.2Sad *
101.2Sad * Redistribution and use in source and binary forms, with or without
111.2Sad * modification, are permitted provided that the following conditions
121.2Sad * are met:
131.2Sad * 1. Redistributions of source code must retain the above copyright
141.2Sad *    notice, this list of conditions and the following disclaimer.
151.2Sad * 2. Redistributions in binary form must reproduce the above copyright
161.2Sad *    notice, this list of conditions and the following disclaimer in the
171.2Sad *    documentation and/or other materials provided with the distribution.
181.11Sriastrad *
191.2Sad * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
201.2Sad * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
211.2Sad * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
221.2Sad * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
231.2Sad * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
241.2Sad * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
251.2Sad * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
261.2Sad * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
271.2Sad * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
281.2Sad * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
291.2Sad * POSSIBILITY OF SUCH DAMAGE.
301.2Sad */
311.2Sad
321.2Sad#include "opt_multiprocessor.h"
331.2Sad#include "opt_lockdebug.h"
341.2Sad
351.2Sad#include <machine/param.h>
361.2Sad#include <machine/asm.h>
371.2Sad
381.2Sad#include "assym.h"
391.2Sad
401.2Sad#undef CURLWP
411.5Smartin#define	CURLWP	(CPUINFO_VA+CI_CURLWP)
421.5Smartin
431.2Sad#if defined(MULTIPROCESSOR)
441.13Sriastrad#define	MB_ACQ	membar #LoadLoad | #LoadStore
451.13Sriastrad#define	MB_REL	membar #LoadStore | #StoreStore
461.2Sad#else
471.13Sriastrad#define	MB_ACQ	/* nothing */
481.13Sriastrad#define	MB_REL	/* nothing */
491.2Sad#endif
501.2Sad
511.2Sad#if !defined(LOCKDEBUG)
521.2Sad
531.2Sad/*
541.2Sad * void mutex_enter(kmutex_t *);
551.2Sad */
561.6Smartin.align	32
571.8SchsENTRY(mutex_enter)
581.3Smartin	sethi	%hi(CURLWP), %o1
591.3Smartin	LDPTR	[%o1 + %lo(CURLWP)], %o1	! current thread
601.3Smartin	CASPTR	[%o0], %g0, %o1			! compare-and-swap
611.13Sriastrad	MB_ACQ
621.3Smartin	brnz,pn	%o1, 1f				! lock was unowned?
631.3Smartin	 nop
641.3Smartin	retl					! - yes, done
651.2Sad	 nop
661.6Smartin1:	ba	_C_LABEL(mutex_vector_enter)	! nope, do it the
671.6Smartin	 nop					! hard way
681.2Sad
691.2Sad/*
701.2Sad * void mutex_exit(kmutex_t *);
711.2Sad *
721.2Sad * XXX This should use a restartable sequence.  See mutex_vector_enter().
731.2Sad */
741.6Smartin.align	32
751.8SchsENTRY(mutex_exit)
761.3Smartin	sethi	%hi(CURLWP), %o1
771.3Smartin	LDPTR	[%o1 + %lo(CURLWP)], %o1	! current thread
781.3Smartin	clr	%o2				! new value (0)
791.13Sriastrad	MB_REL
801.3Smartin	CASPTR	[%o0], %o1, %o2			! compare-and-swap
811.4Smartin	cmp	%o1, %o2
821.4Smartin	bne,pn	CCCR, 1f			! nope, hard case
831.2Sad	 nop
841.2Sad	retl
851.2Sad	 nop
861.6Smartin1:	ba _C_LABEL(mutex_vector_exit)
871.3Smartin	 nop
881.2Sad
891.2Sad#endif	/* !LOCKDEBUG */
90