1 /* $NetBSD: ltsleep.c,v 1.34 2016/01/26 23:12:17 pooka 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 1.34 2016/01/26 23:12:17 pooka 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, kmutex_t *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 mutex_spin_enter(&qlock); 80 LIST_INSERT_HEAD(&sleepers, <s, entries); 81 mutex_exit(&qlock); 82 83 if (timo) { 84 if (kinterlock) { 85 rv = cv_timedwait(<s.kcv, kinterlock, timo); 86 } else { 87 /* 88 * Calculate wakeup-time. 89 */ 90 ts.tv_sec = timo / hz; 91 ts.tv_nsec = (timo % hz) * (1000000000/hz); 92 rv = rumpuser_cv_timedwait(lts.ucv, rump_giantlock, 93 ts.tv_sec, ts.tv_nsec); 94 } 95 96 if (rv != 0) 97 rv = EWOULDBLOCK; 98 } else { 99 if (kinterlock) { 100 cv_wait(<s.kcv, kinterlock); 101 } else { 102 rumpuser_cv_wait(lts.ucv, rump_giantlock); 103 } 104 rv = 0; 105 } 106 107 mutex_spin_enter(&qlock); 108 LIST_REMOVE(<s, entries); 109 mutex_exit(&qlock); 110 111 if (kinterlock) 112 cv_destroy(<s.kcv); 113 else 114 rumpuser_cv_destroy(lts.ucv); 115 116 return rv; 117 } 118 119 int 120 tsleep(wchan_t ident, pri_t prio, const char *wmesg, int timo) 121 { 122 int rv, nlocks; 123 124 /* 125 * Since we cannot use slock as the rumpuser interlock, 126 * require that everyone using this prehistoric interface 127 * is biglocked. Wrap around the biglock and drop lockcnt, 128 * but retain the rumpuser mutex so that we can use it as an 129 * interlock to rumpuser_cv_wait(). 130 */ 131 rump_kernel_bigwrap(&nlocks); 132 rv = sleeper(ident, timo, NULL); 133 rump_kernel_bigunwrap(nlocks); 134 135 return rv; 136 } 137 138 int 139 mtsleep(wchan_t ident, pri_t prio, const char *wmesg, int timo, kmutex_t *lock) 140 { 141 int rv; 142 143 rv = sleeper(ident, timo, lock); 144 if (prio & PNORELOCK) 145 mutex_exit(lock); 146 147 return rv; 148 } 149 150 void 151 wakeup(wchan_t ident) 152 { 153 struct ltsleeper *ltsp; 154 155 mutex_spin_enter(&qlock); 156 LIST_FOREACH(ltsp, &sleepers, entries) { 157 if (ltsp->id == ident) { 158 if (ltsp->iskwait) { 159 cv_broadcast(<sp->kcv); 160 } else { 161 rumpuser_cv_broadcast(ltsp->ucv); 162 } 163 } 164 } 165 mutex_exit(&qlock); 166 } 167 168 void 169 rump_tsleep_init() 170 { 171 172 mutex_init(&qlock, MUTEX_SPIN, IPL_NONE); 173 } 174