1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22/*
23 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26	.file	"smt_pause.s"
27
28/*
29 * void smt_pause(void)
30 *
31 * Do nothing efficiently.
32 *
33 */
34
35#include <sys/asm_linkage.h>
36#include <sys/niagaraasi.h>
37#include <sys/asi.h>
38#include <sys/stack.h>
39
40#if defined(NIAGARA_IMPL)
41#include <assym.h>
42#endif
43
44	ENTRY(smt_pause)
45#if defined(NIAGARA2_IMPL) || defined(VFALLS_IMPL) || defined(KT_IMPL)
46	rd	%ccr, %g0
47	rd	%ccr, %g0
48	retl
49	rd	%ccr, %g0
50#else	/* NIAGARA2_IMPL */
51#define	BANKS	(4 * 64)	/* 4 cachelines, cover all banks */
52	save %sp, -SA(MINFRAME+BANKS), %sp
53
54	ld      [%g7 + UL_LWPID], %i3   ! curthread->ul_lwpid
55	add	%fp, STACK_BIAS-BANKS, %i0
56	and     %i3, 0x3, %i2           ! save last 2 bits
57	sllx    %i2, 0x6, %i1           ! pick a slot
58	add	%i1, %i0, %o0
59
60	casx	[%o0], %g0, %g0
61	casx    [%o0], %g0, %g0
62	casx    [%o0], %g0, %g0
63	ret
64	restore
65#endif	/* NIAGARA2_IMPL */
66	SET_SIZE(smt_pause)
67
68