Home | History | Annotate | Line # | Download | only in rumpkern
klock.c revision 1.1 
      1 /*	$NetBSD: klock.c,v 1.1 2010/05/18 15:12:19 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 1.1 2010/05/18 15:12:19 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 
     45 static volatile int lockcnt;
     46 
     47 bool
     48 kernel_biglocked()
     49 {
     50 
     51 	return rumpuser_mutex_held(rump_giantlock) && lockcnt > 0;
     52 }
     53 
     54 void
     55 kernel_unlock_allbutone(int *countp)
     56 {
     57 	int minusone = lockcnt-1;
     58 
     59 	KASSERT(kernel_biglocked());
     60 	if (minusone) {
     61 		_kernel_unlock(minusone, countp);
     62 	}
     63 	KASSERT(lockcnt == 1);
     64 	*countp = minusone;
     65 
     66 	/*
     67 	 * We drop lockcnt to 0 since rumpuser doesn't know that the
     68 	 * kernel biglock is being used as the interlock for cv in
     69 	 * tsleep.
     70 	 */
     71 	lockcnt = 0;
     72 }
     73 
     74 void
     75 kernel_ununlock_allbutone(int nlocks)
     76 {
     77 
     78 	KASSERT(rumpuser_mutex_held(rump_giantlock) && lockcnt == 0);
     79 	lockcnt = 1;
     80 	_kernel_lock(nlocks);
     81 }
     82 
     83 void
     84 _kernel_lock(int nlocks)
     85 {
     86 
     87 	while (nlocks--) {
     88 		if (!rumpuser_mutex_tryenter(rump_giantlock)) {
     89 			struct lwp *l = curlwp;
     90 
     91 			rump_unschedule_cpu1(l, NULL);
     92 			rumpuser_mutex_enter_nowrap(rump_giantlock);
     93 			rump_schedule_cpu(l);
     94 		}
     95 		lockcnt++;
     96 	}
     97 }
     98 
     99 void
    100 _kernel_unlock(int nlocks, int *countp)
    101 {
    102 
    103 	if (!rumpuser_mutex_held(rump_giantlock)) {
    104 		KASSERT(nlocks == 0);
    105 		if (countp)
    106 			*countp = 0;
    107 		return;
    108 	}
    109 
    110 	if (countp)
    111 		*countp = lockcnt;
    112 	if (nlocks == 0)
    113 		nlocks = lockcnt;
    114 	if (nlocks == -1) {
    115 		KASSERT(lockcnt == 1);
    116 		nlocks = 1;
    117 	}
    118 	KASSERT(nlocks <= lockcnt);
    119 	while (nlocks--) {
    120 		lockcnt--;
    121 		rumpuser_mutex_exit(rump_giantlock);
    122 	}
    123 }
    124 
    125 void
    126 rump_user_unschedule(int nlocks, int *countp, void *interlock)
    127 {
    128 
    129 	_kernel_unlock(nlocks, countp);
    130 	/*
    131 	 * XXX: technically we should unschedule_cpu1() here, but that
    132 	 * requires rump_intr_enter/exit to be implemented.
    133 	 */
    134 	rump_unschedule_cpu_interlock(curlwp, interlock);
    135 }
    136 
    137 void
    138 rump_user_schedule(int nlocks, void *interlock)
    139 {
    140 
    141 	rump_schedule_cpu_interlock(curlwp, interlock);
    142 
    143 	if (nlocks)
    144 		_kernel_lock(nlocks);
    145 }
    146