1 /* $NetBSD: ltsleep.c,v 1.36 2020/03/14 20:23:51 ad Exp $ */ 2 3 /* 4 * Copyright (c) 2009, 2010 Antti Kantee. All Rights Reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 /* 29 * Implementation of the tsleep/mtsleep kernel sleep interface. There 30 * are two sides to our implementation. For historic spinlocks we 31 * assume the kernel is giantlocked and use kernel giantlock as the 32 * wait interlock. For mtsleep, we use the interlock supplied by 33 * the caller. This duality leads to some if/else messiness in the code ... 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: ltsleep.c,v 1.36 2020/03/14 20:23:51 ad Exp $"); 38 39 #include <sys/param.h> 40 #include <sys/kernel.h> 41 #include <sys/proc.h> 42 #include <sys/queue.h> 43 44 #include <rump-sys/kern.h> 45 46 #include <rump/rumpuser.h> 47 48 struct ltsleeper { 49 wchan_t id; 50 union { 51 struct rumpuser_cv *user; 52 kcondvar_t kern; 53 } u; 54 bool iskwait; 55 LIST_ENTRY(ltsleeper) entries; 56 }; 57 #define ucv u.user 58 #define kcv u.kern 59 60 static LIST_HEAD(, ltsleeper) sleepers = LIST_HEAD_INITIALIZER(sleepers); 61 static kmutex_t qlock; 62 63 static int 64 sleeper(wchan_t ident, int timo, bool kinterlock) 65 { 66 struct ltsleeper lts; 67 struct timespec ts; 68 int rv; 69 70 lts.id = ident; 71 if (kinterlock) { 72 lts.iskwait = true; 73 cv_init(<s.kcv, "mtsleep"); 74 } else { 75 lts.iskwait = false; 76 rumpuser_cv_init(<s.ucv); 77 } 78 79 LIST_INSERT_HEAD(&sleepers, <s, entries); 80 81 if (timo) { 82 if (kinterlock) { 83 rv = cv_timedwait(<s.kcv, &qlock, timo); 84 } else { 85 /* 86 * Calculate wakeup-time. 87 */ 88 ts.tv_sec = timo / hz; 89 ts.tv_nsec = (timo % hz) * (1000000000/hz); 90 mutex_spin_exit(&qlock); 91 rv = rumpuser_cv_timedwait(lts.ucv, rump_giantlock, 92 ts.tv_sec, ts.tv_nsec); 93 mutex_spin_enter(&qlock); 94 } 95 96 if (rv != 0) 97 rv = EWOULDBLOCK; 98 } else { 99 if (kinterlock) { 100 cv_wait(<s.kcv, &qlock); 101 } else { 102 mutex_spin_exit(&qlock); 103 rumpuser_cv_wait(lts.ucv, rump_giantlock); 104 mutex_spin_enter(&qlock); 105 } 106 rv = 0; 107 } 108 109 LIST_REMOVE(<s, entries); 110 mutex_spin_exit(&qlock); 111 112 if (kinterlock) 113 cv_destroy(<s.kcv); 114 else 115 rumpuser_cv_destroy(lts.ucv); 116 117 return rv; 118 } 119 120 int 121 tsleep(wchan_t ident, pri_t prio, const char *wmesg, int timo) 122 { 123 int rv, nlocks; 124 125 /* 126 * Since we cannot use slock as the rumpuser interlock, 127 * require that everyone using this prehistoric interface 128 * is biglocked. Wrap around the biglock and drop lockcnt, 129 * but retain the rumpuser mutex so that we can use it as an 130 * interlock to rumpuser_cv_wait(). 131 */ 132 rump_kernel_bigwrap(&nlocks); 133 mutex_spin_enter(&qlock); 134 rv = sleeper(ident, timo, false); 135 rump_kernel_bigunwrap(nlocks); 136 137 return rv; 138 } 139 140 int 141 mtsleep(wchan_t ident, pri_t prio, const char *wmesg, int timo, kmutex_t *lock) 142 { 143 int rv; 144 145 mutex_spin_enter(&qlock); 146 mutex_exit(lock); 147 rv = sleeper(ident, timo, true); 148 if ((prio & PNORELOCK) == 0) 149 mutex_enter(lock); 150 151 return rv; 152 } 153 154 void 155 wakeup(wchan_t ident) 156 { 157 struct ltsleeper *ltsp; 158 159 mutex_spin_enter(&qlock); 160 LIST_FOREACH(ltsp, &sleepers, entries) { 161 if (ltsp->id == ident) { 162 if (ltsp->iskwait) { 163 cv_broadcast(<sp->kcv); 164 } else { 165 rumpuser_cv_broadcast(ltsp->ucv); 166 } 167 } 168 } 169 mutex_exit(&qlock); 170 } 171 172 void 173 rump_tsleep_init() 174 { 175 176 mutex_init(&qlock, MUTEX_SPIN, IPL_NONE); 177 } 178