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 * $DragonFly: src/sys/kern/kern_kthread.c,v 1.13 2006/12/18 20:41:01 dillon Exp $ 28 */ 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/proc.h> 33 #include <sys/kthread.h> 34 #include <sys/ptrace.h> 35 #include <sys/resourcevar.h> 36 #include <sys/signalvar.h> 37 #include <sys/unistd.h> 38 #include <sys/wait.h> 39 40 #include <machine/stdarg.h> 41 42 static struct lwkt_token kpsus_token = LWKT_TOKEN_INITIALIZER(kpsus_token); 43 44 45 /* 46 * Create a kernel process/thread/whatever. It shares it's address space 47 * with proc0 - ie: kernel only. 5.x compatible. 48 * 49 * All kthreads are created as MPSAFE threads. 50 */ 51 int 52 kthread_create(void (*func)(void *), void *arg, 53 struct thread **tdp, const char *fmt, ...) 54 { 55 thread_t td; 56 __va_list ap; 57 58 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, -1, TDF_VERBOSE); 59 if (tdp) 60 *tdp = td; 61 cpu_set_thread_handler(td, kthread_exit, func, arg); 62 63 /* 64 * Set up arg0 for 'ps' etc 65 */ 66 __va_start(ap, fmt); 67 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 68 __va_end(ap); 69 70 td->td_ucred = crhold(proc0.p_ucred); 71 72 /* 73 * Schedule the thread to run 74 */ 75 lwkt_schedule(td); 76 return 0; 77 } 78 79 int 80 kthread_create_cpu(void (*func)(void *), void *arg, 81 struct thread **tdp, int cpu, const char *fmt, ...) 82 { 83 thread_t td; 84 __va_list ap; 85 86 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, cpu, TDF_VERBOSE); 87 if (tdp) 88 *tdp = td; 89 cpu_set_thread_handler(td, kthread_exit, func, arg); 90 91 /* 92 * Set up arg0 for 'ps' etc 93 */ 94 __va_start(ap, fmt); 95 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 96 __va_end(ap); 97 98 td->td_ucred = crhold(proc0.p_ucred); 99 100 /* 101 * Schedule the thread to run 102 */ 103 lwkt_schedule(td); 104 return 0; 105 } 106 107 /* 108 * Same as kthread_create() but you can specify a custom stack size. 109 */ 110 int 111 kthread_create_stk(void (*func)(void *), void *arg, 112 struct thread **tdp, int stksize, const char *fmt, ...) 113 { 114 thread_t td; 115 __va_list ap; 116 117 td = lwkt_alloc_thread(NULL, stksize, -1, TDF_VERBOSE); 118 if (tdp) 119 *tdp = td; 120 cpu_set_thread_handler(td, kthread_exit, func, arg); 121 122 __va_start(ap, fmt); 123 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 124 __va_end(ap); 125 126 lwkt_schedule(td); 127 return 0; 128 } 129 130 /* 131 * Destroy an LWKT thread. Warning! This function is not called when 132 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 133 * uses a different reaping mechanism. 134 * 135 * XXX duplicates lwkt_exit() 136 */ 137 void 138 kthread_exit(void) 139 { 140 lwkt_exit(); 141 } 142 143 /* 144 * Start a kernel process. This is called after a fork() call in 145 * mi_startup() in the file kern/init_main.c. 146 * 147 * This function is used to start "internal" daemons and intended 148 * to be called from SYSINIT(). 149 * 150 * These threads are created MPSAFE. 151 */ 152 void 153 kproc_start(const void *udata) 154 { 155 const struct kproc_desc *kp = udata; 156 int error; 157 158 error = kthread_create((void (*)(void *))kp->func, NULL, 159 kp->global_threadpp, kp->arg0); 160 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 161 if (error) 162 panic("kproc_start: %s: error %d", kp->arg0, error); 163 } 164 165 /* 166 * Advise a kernel process to suspend (or resume) in its main loop. 167 * Participation is voluntary. 168 */ 169 int 170 suspend_kproc(struct thread *td, int timo) 171 { 172 if (td->td_proc == NULL) { 173 lwkt_gettoken(&kpsus_token); 174 td->td_flags |= TDF_STOPREQ; /* request thread pause */ 175 wakeup(td); 176 while (td->td_flags & TDF_STOPREQ) { 177 int error = tsleep(td, 0, "suspkp", timo); 178 if (error == EWOULDBLOCK) 179 break; 180 } 181 td->td_flags &= ~TDF_STOPREQ; 182 lwkt_reltoken(&kpsus_token); 183 return(0); 184 } else { 185 return(EINVAL); /* not a kernel thread */ 186 } 187 } 188 189 void 190 kproc_suspend_loop(void) 191 { 192 struct thread *td = curthread; 193 194 if (td->td_flags & TDF_STOPREQ) { 195 lwkt_gettoken(&kpsus_token); 196 td->td_flags &= ~TDF_STOPREQ; 197 while ((td->td_flags & TDF_WAKEREQ) == 0) { 198 wakeup(td); 199 tsleep(td, 0, "kpsusp", 0); 200 } 201 td->td_flags &= ~TDF_WAKEREQ; 202 wakeup(td); 203 lwkt_reltoken(&kpsus_token); 204 } 205 } 206 207