1 /* 2 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/sys/kern/kern_kthread.c,v 1.5.2.3 2001/12/25 01:51:14 dillon Exp $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/proc.h> 32 #include <sys/kthread.h> 33 #include <sys/ptrace.h> 34 #include <sys/resourcevar.h> 35 #include <sys/signalvar.h> 36 #include <sys/unistd.h> 37 #include <sys/wait.h> 38 39 #include <machine/stdarg.h> 40 41 static struct lwkt_token kpsus_token = LWKT_TOKEN_INITIALIZER(kpsus_token); 42 43 44 /* 45 * Create a new lightweight kernel thread. 46 */ 47 static int __printflike(5, 0) 48 _kthread_create(void (*func)(void *), void *arg, 49 struct thread **tdp, int cpu, const char *fmt, __va_list ap) 50 { 51 thread_t td; 52 int flags = 0; 53 54 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, cpu, flags); 55 if (tdp) 56 *tdp = td; 57 cpu_set_thread_handler(td, kthread_exit, func, arg); 58 59 /* 60 * Set up arg0 for 'ps' etc 61 */ 62 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 63 64 td->td_ucred = crhold(proc0.p_ucred); 65 66 /* 67 * Schedule the thread to run 68 */ 69 lwkt_schedule(td); 70 71 return 0; 72 } 73 74 /* 75 * Creates a lwkt. No CPU preference. 76 */ 77 int 78 kthread_create(void (*func)(void *), void *arg, 79 struct thread **tdp, const char *fmt, ...) 80 { 81 __va_list ap; 82 int ret; 83 84 __va_start(ap, fmt); 85 ret = _kthread_create(func, arg, tdp, -1, fmt, ap); 86 __va_end(ap); 87 88 return ret; 89 } 90 91 /* 92 * Creates a lwkt and schedule it to run in a specific CPU. 93 * 94 */ 95 int 96 kthread_create_cpu(void (*func)(void *), void *arg, 97 struct thread **tdp, int cpu, const char *fmt, ...) 98 { 99 __va_list ap; 100 int ret; 101 102 __va_start(ap, fmt); 103 ret = _kthread_create(func, arg, tdp, cpu, fmt, ap); 104 __va_end(ap); 105 106 return ret; 107 } 108 109 #if 0 110 /* 111 * Same as kthread_create() but you can specify a custom stack size. 112 */ 113 int 114 kthread_create_stk(void (*func)(void *), void *arg, 115 struct thread **tdp, int stksize, const char *fmt, ...) 116 { 117 thread_t td; 118 __va_list ap; 119 120 td = lwkt_alloc_thread(NULL, stksize, -1, 0); 121 if (tdp) 122 *tdp = td; 123 cpu_set_thread_handler(td, kthread_exit, func, arg); 124 125 __va_start(ap, fmt); 126 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 127 __va_end(ap); 128 129 lwkt_schedule(td); 130 return 0; 131 } 132 #endif 133 134 /* 135 * Destroy an LWKT thread. Warning! This function is not called when 136 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 137 * uses a different reaping mechanism. 138 * 139 * XXX duplicates lwkt_exit() 140 */ 141 void 142 kthread_exit(void) 143 { 144 lwkt_exit(); 145 } 146 147 /* 148 * Start a kernel process. This is called after a fork() call in 149 * mi_startup() in the file kern/init_main.c. 150 * 151 * This function is used to start "internal" daemons and intended 152 * to be called from SYSINIT(). 153 * 154 * These threads are created MPSAFE. 155 */ 156 void 157 kproc_start(const void *udata) 158 { 159 const struct kproc_desc *kp = udata; 160 int error; 161 162 error = kthread_create((void (*)(void *))kp->func, NULL, 163 kp->global_threadpp, "%s", kp->arg0); 164 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 165 if (error) 166 panic("kproc_start: %s: error %d", kp->arg0, error); 167 } 168 169 /* 170 * Advise a kernel process to suspend (or resume) in its main loop. 171 * Participation is voluntary. 172 */ 173 int 174 suspend_kproc(struct thread *td, int timo) 175 { 176 if (td->td_proc == NULL) { 177 lwkt_gettoken(&kpsus_token); 178 /* request thread pause */ 179 atomic_set_int(&td->td_mpflags, TDF_MP_STOPREQ); 180 wakeup(td); 181 while (td->td_mpflags & TDF_MP_STOPREQ) { 182 int error = tsleep(td, 0, "suspkp", timo); 183 if (error == EWOULDBLOCK) 184 break; 185 } 186 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 187 lwkt_reltoken(&kpsus_token); 188 return(0); 189 } else { 190 return(EINVAL); /* not a kernel thread */ 191 } 192 } 193 194 void 195 kproc_suspend_loop(void) 196 { 197 struct thread *td = curthread; 198 199 if (td->td_mpflags & TDF_MP_STOPREQ) { 200 lwkt_gettoken(&kpsus_token); 201 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 202 while ((td->td_mpflags & TDF_MP_WAKEREQ) == 0) { 203 wakeup(td); 204 tsleep(td, 0, "kpsusp", 0); 205 } 206 atomic_clear_int(&td->td_mpflags, TDF_MP_WAKEREQ); 207 wakeup(td); 208 lwkt_reltoken(&kpsus_token); 209 } 210 } 211 212