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klock.c revision 1.2.4.2
      1  1.2.4.2  yamt /*	$NetBSD: klock.c,v 1.2.4.2 2010/08/11 22:55:06 yamt Exp $	*/
      2  1.2.4.2  yamt 
      3  1.2.4.2  yamt /*
      4  1.2.4.2  yamt  * Copyright (c) 2007-2010 Antti Kantee.  All Rights Reserved.
      5  1.2.4.2  yamt  *
      6  1.2.4.2  yamt  * Development of this software was supported by the
      7  1.2.4.2  yamt  * Finnish Cultural Foundation.
      8  1.2.4.2  yamt  *
      9  1.2.4.2  yamt  * Redistribution and use in source and binary forms, with or without
     10  1.2.4.2  yamt  * modification, are permitted provided that the following conditions
     11  1.2.4.2  yamt  * are met:
     12  1.2.4.2  yamt  * 1. Redistributions of source code must retain the above copyright
     13  1.2.4.2  yamt  *    notice, this list of conditions and the following disclaimer.
     14  1.2.4.2  yamt  * 2. Redistributions in binary form must reproduce the above copyright
     15  1.2.4.2  yamt  *    notice, this list of conditions and the following disclaimer in the
     16  1.2.4.2  yamt  *    documentation and/or other materials provided with the distribution.
     17  1.2.4.2  yamt  *
     18  1.2.4.2  yamt  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     19  1.2.4.2  yamt  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     20  1.2.4.2  yamt  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     21  1.2.4.2  yamt  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     22  1.2.4.2  yamt  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  1.2.4.2  yamt  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
     24  1.2.4.2  yamt  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  1.2.4.2  yamt  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  1.2.4.2  yamt  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  1.2.4.2  yamt  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  1.2.4.2  yamt  * SUCH DAMAGE.
     29  1.2.4.2  yamt  */
     30  1.2.4.2  yamt 
     31  1.2.4.2  yamt #include <sys/cdefs.h>
     32  1.2.4.2  yamt __KERNEL_RCSID(0, "$NetBSD: klock.c,v 1.2.4.2 2010/08/11 22:55:06 yamt Exp $");
     33  1.2.4.2  yamt 
     34  1.2.4.2  yamt #include <sys/param.h>
     35  1.2.4.2  yamt #include <sys/systm.h>
     36  1.2.4.2  yamt 
     37  1.2.4.2  yamt #include <rump/rumpuser.h>
     38  1.2.4.2  yamt 
     39  1.2.4.2  yamt #include "rump_private.h"
     40  1.2.4.2  yamt 
     41  1.2.4.2  yamt /*
     42  1.2.4.2  yamt  * giant lock
     43  1.2.4.2  yamt  */
     44  1.2.4.2  yamt 
     45  1.2.4.2  yamt static volatile int lockcnt;
     46  1.2.4.2  yamt 
     47  1.2.4.2  yamt bool
     48  1.2.4.2  yamt rump_kernel_isbiglocked()
     49  1.2.4.2  yamt {
     50  1.2.4.2  yamt 
     51  1.2.4.2  yamt 	return rumpuser_mutex_held(rump_giantlock) && lockcnt > 0;
     52  1.2.4.2  yamt }
     53  1.2.4.2  yamt 
     54  1.2.4.2  yamt void
     55  1.2.4.2  yamt rump_kernel_unlock_allbutone(int *countp)
     56  1.2.4.2  yamt {
     57  1.2.4.2  yamt 	int minusone = lockcnt-1;
     58  1.2.4.2  yamt 
     59  1.2.4.2  yamt 	KASSERT(rump_kernel_isbiglocked());
     60  1.2.4.2  yamt 	if (minusone) {
     61  1.2.4.2  yamt 		_kernel_unlock(minusone, countp);
     62  1.2.4.2  yamt 	}
     63  1.2.4.2  yamt 	KASSERT(lockcnt == 1);
     64  1.2.4.2  yamt 	*countp = minusone;
     65  1.2.4.2  yamt 
     66  1.2.4.2  yamt 	/*
     67  1.2.4.2  yamt 	 * We drop lockcnt to 0 since rumpuser doesn't know that the
     68  1.2.4.2  yamt 	 * kernel biglock is being used as the interlock for cv in
     69  1.2.4.2  yamt 	 * tsleep.
     70  1.2.4.2  yamt 	 */
     71  1.2.4.2  yamt 	lockcnt = 0;
     72  1.2.4.2  yamt }
     73  1.2.4.2  yamt 
     74  1.2.4.2  yamt void
     75  1.2.4.2  yamt rump_kernel_ununlock_allbutone(int nlocks)
     76  1.2.4.2  yamt {
     77  1.2.4.2  yamt 
     78  1.2.4.2  yamt 	KASSERT(rumpuser_mutex_held(rump_giantlock) && lockcnt == 0);
     79  1.2.4.2  yamt 	lockcnt = 1;
     80  1.2.4.2  yamt 	_kernel_lock(nlocks);
     81  1.2.4.2  yamt }
     82  1.2.4.2  yamt 
     83  1.2.4.2  yamt void
     84  1.2.4.2  yamt _kernel_lock(int nlocks)
     85  1.2.4.2  yamt {
     86  1.2.4.2  yamt 
     87  1.2.4.2  yamt 	while (nlocks--) {
     88  1.2.4.2  yamt 		if (!rumpuser_mutex_tryenter(rump_giantlock)) {
     89  1.2.4.2  yamt 			struct lwp *l = curlwp;
     90  1.2.4.2  yamt 
     91  1.2.4.2  yamt 			rump_unschedule_cpu1(l, NULL);
     92  1.2.4.2  yamt 			rumpuser_mutex_enter_nowrap(rump_giantlock);
     93  1.2.4.2  yamt 			rump_schedule_cpu(l);
     94  1.2.4.2  yamt 		}
     95  1.2.4.2  yamt 		lockcnt++;
     96  1.2.4.2  yamt 	}
     97  1.2.4.2  yamt }
     98  1.2.4.2  yamt 
     99  1.2.4.2  yamt void
    100  1.2.4.2  yamt _kernel_unlock(int nlocks, int *countp)
    101  1.2.4.2  yamt {
    102  1.2.4.2  yamt 
    103  1.2.4.2  yamt 	if (!rumpuser_mutex_held(rump_giantlock)) {
    104  1.2.4.2  yamt 		KASSERT(nlocks == 0);
    105  1.2.4.2  yamt 		if (countp)
    106  1.2.4.2  yamt 			*countp = 0;
    107  1.2.4.2  yamt 		return;
    108  1.2.4.2  yamt 	}
    109  1.2.4.2  yamt 
    110  1.2.4.2  yamt 	if (countp)
    111  1.2.4.2  yamt 		*countp = lockcnt;
    112  1.2.4.2  yamt 	if (nlocks == 0)
    113  1.2.4.2  yamt 		nlocks = lockcnt;
    114  1.2.4.2  yamt 	if (nlocks == -1) {
    115  1.2.4.2  yamt 		KASSERT(lockcnt == 1);
    116  1.2.4.2  yamt 		nlocks = 1;
    117  1.2.4.2  yamt 	}
    118  1.2.4.2  yamt 	KASSERT(nlocks <= lockcnt);
    119  1.2.4.2  yamt 	while (nlocks--) {
    120  1.2.4.2  yamt 		lockcnt--;
    121  1.2.4.2  yamt 		rumpuser_mutex_exit(rump_giantlock);
    122  1.2.4.2  yamt 	}
    123  1.2.4.2  yamt }
    124  1.2.4.2  yamt 
    125  1.2.4.2  yamt void
    126  1.2.4.2  yamt rump_user_unschedule(int nlocks, int *countp, void *interlock)
    127  1.2.4.2  yamt {
    128  1.2.4.2  yamt 
    129  1.2.4.2  yamt 	_kernel_unlock(nlocks, countp);
    130  1.2.4.2  yamt 	/*
    131  1.2.4.2  yamt 	 * XXX: technically we should unschedule_cpu1() here, but that
    132  1.2.4.2  yamt 	 * requires rump_intr_enter/exit to be implemented.
    133  1.2.4.2  yamt 	 */
    134  1.2.4.2  yamt 	rump_unschedule_cpu_interlock(curlwp, interlock);
    135  1.2.4.2  yamt }
    136  1.2.4.2  yamt 
    137  1.2.4.2  yamt void
    138  1.2.4.2  yamt rump_user_schedule(int nlocks, void *interlock)
    139  1.2.4.2  yamt {
    140  1.2.4.2  yamt 
    141  1.2.4.2  yamt 	rump_schedule_cpu_interlock(curlwp, interlock);
    142  1.2.4.2  yamt 
    143  1.2.4.2  yamt 	if (nlocks)
    144  1.2.4.2  yamt 		_kernel_lock(nlocks);
    145  1.2.4.2  yamt }
    146