1/*	$NetBSD: klock.c,v 1.3 2010/12/01 14:59:38 pooka Exp $	*/
2
3/*
4 * Copyright (c) 2007-2010 Antti Kantee.  All Rights Reserved.
5 *
6 * Development of this software was supported by the
7 * Finnish Cultural Foundation.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
19 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
24 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31#include <sys/cdefs.h>
32__KERNEL_RCSID(0, "$NetBSD: klock.c,v 1.3 2010/12/01 14:59:38 pooka Exp $");
33
34#include <sys/param.h>
35#include <sys/systm.h>
36
37#include <rump/rumpuser.h>
38
39#include "rump_private.h"
40
41/*
42 * giant lock
43 */
44
45struct rumpuser_mtx *rump_giantlock;
46static int giantcnt;
47static struct lwp *giantowner;
48
49void
50rump_kernel_bigwrap(int *nlocks)
51{
52
53	KASSERT(giantcnt > 0 && curlwp == giantowner);
54	giantowner = NULL;
55	*nlocks = giantcnt;
56	giantcnt = 0;
57}
58
59void
60rump_kernel_bigunwrap(int nlocks)
61{
62
63	KASSERT(giantowner == NULL);
64	giantowner = curlwp;
65	giantcnt = nlocks;
66}
67
68void
69_kernel_lock(int nlocks)
70{
71	struct lwp *l = curlwp;
72
73	while (nlocks) {
74		if (giantowner == l) {
75			giantcnt += nlocks;
76			nlocks = 0;
77		} else {
78			if (!rumpuser_mutex_tryenter(rump_giantlock)) {
79				rump_unschedule_cpu1(l, NULL);
80				rumpuser_mutex_enter_nowrap(rump_giantlock);
81				rump_schedule_cpu(l);
82			}
83			giantowner = l;
84			giantcnt = 1;
85			nlocks--;
86		}
87	}
88}
89
90void
91_kernel_unlock(int nlocks, int *countp)
92{
93
94	if (giantowner != curlwp) {
95		KASSERT(nlocks == 0);
96		if (countp)
97			*countp = 0;
98		return;
99	}
100
101	if (countp)
102		*countp = giantcnt;
103	if (nlocks == 0)
104		nlocks = giantcnt;
105	if (nlocks == -1) {
106		KASSERT(giantcnt == 1);
107		nlocks = 1;
108	}
109	KASSERT(nlocks <= giantcnt);
110	while (nlocks--) {
111		giantcnt--;
112	}
113
114	if (giantcnt == 0) {
115		giantowner = NULL;
116		rumpuser_mutex_exit(rump_giantlock);
117	}
118}
119
120bool
121_kernel_locked_p(void)
122{
123
124	return giantowner == curlwp;
125}
126
127void
128rump_user_unschedule(int nlocks, int *countp, void *interlock)
129{
130
131	_kernel_unlock(nlocks, countp);
132	/*
133	 * XXX: technically we should unschedule_cpu1() here, but that
134	 * requires rump_intr_enter/exit to be implemented.
135	 */
136	rump_unschedule_cpu_interlock(curlwp, interlock);
137}
138
139void
140rump_user_schedule(int nlocks, void *interlock)
141{
142
143	rump_schedule_cpu_interlock(curlwp, interlock);
144
145	if (nlocks)
146		_kernel_lock(nlocks);
147}
148