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 <sys/mplock2.h> 41 42 #include <machine/stdarg.h> 43 44 static struct lwkt_token kpsus_token = LWKT_TOKEN_MP_INITIALIZER(kpsus_token); 45 46 47 /* 48 * Create a kernel process/thread/whatever. It shares it's address space 49 * with proc0 - ie: kernel only. 5.x compatible. 50 * 51 * All kthreads are created as MPSAFE threads. 52 */ 53 int 54 kthread_create(void (*func)(void *), void *arg, 55 struct thread **tdp, const char *fmt, ...) 56 { 57 thread_t td; 58 __va_list ap; 59 60 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, -1, TDF_VERBOSE); 61 if (tdp) 62 *tdp = td; 63 cpu_set_thread_handler(td, kthread_exit, func, arg); 64 65 /* 66 * Set up arg0 for 'ps' etc 67 */ 68 __va_start(ap, fmt); 69 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 70 __va_end(ap); 71 72 td->td_ucred = crhold(proc0.p_ucred); 73 74 /* 75 * Schedule the thread to run 76 */ 77 lwkt_schedule(td); 78 return 0; 79 } 80 81 int 82 kthread_create_cpu(void (*func)(void *), void *arg, 83 struct thread **tdp, int cpu, const char *fmt, ...) 84 { 85 thread_t td; 86 __va_list ap; 87 88 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, cpu, TDF_VERBOSE); 89 if (tdp) 90 *tdp = td; 91 cpu_set_thread_handler(td, kthread_exit, func, arg); 92 93 /* 94 * Set up arg0 for 'ps' etc 95 */ 96 __va_start(ap, fmt); 97 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 98 __va_end(ap); 99 100 td->td_ucred = crhold(proc0.p_ucred); 101 102 /* 103 * Schedule the thread to run 104 */ 105 lwkt_schedule(td); 106 return 0; 107 } 108 109 /* 110 * Same as kthread_create() but you can specify a custom stack size. 111 */ 112 int 113 kthread_create_stk(void (*func)(void *), void *arg, 114 struct thread **tdp, int stksize, const char *fmt, ...) 115 { 116 thread_t td; 117 __va_list ap; 118 119 td = lwkt_alloc_thread(NULL, stksize, -1, TDF_VERBOSE); 120 if (tdp) 121 *tdp = td; 122 cpu_set_thread_handler(td, kthread_exit, func, arg); 123 124 __va_start(ap, fmt); 125 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 126 __va_end(ap); 127 128 lwkt_schedule(td); 129 return 0; 130 } 131 132 /* 133 * Destroy an LWKT thread. Warning! This function is not called when 134 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 135 * uses a different reaping mechanism. 136 * 137 * XXX duplicates lwkt_exit() 138 */ 139 void 140 kthread_exit(void) 141 { 142 lwkt_exit(); 143 } 144 145 /* 146 * Start a kernel process. This is called after a fork() call in 147 * mi_startup() in the file kern/init_main.c. 148 * 149 * This function is used to start "internal" daemons and intended 150 * to be called from SYSINIT(). 151 * 152 * These threads are created MPSAFE. 153 */ 154 void 155 kproc_start(const void *udata) 156 { 157 const struct kproc_desc *kp = udata; 158 int error; 159 160 error = kthread_create((void (*)(void *))kp->func, NULL, 161 kp->global_threadpp, kp->arg0); 162 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 163 if (error) 164 panic("kproc_start: %s: error %d", kp->arg0, error); 165 } 166 167 /* 168 * Advise a kernel process to suspend (or resume) in its main loop. 169 * Participation is voluntary. 170 */ 171 int 172 suspend_kproc(struct thread *td, int timo) 173 { 174 if (td->td_proc == NULL) { 175 lwkt_gettoken(&kpsus_token); 176 td->td_flags |= TDF_STOPREQ; /* request thread pause */ 177 wakeup(td); 178 while (td->td_flags & TDF_STOPREQ) { 179 int error = tsleep(td, 0, "suspkp", timo); 180 if (error == EWOULDBLOCK) 181 break; 182 } 183 td->td_flags &= ~TDF_STOPREQ; 184 lwkt_reltoken(&kpsus_token); 185 return(0); 186 } else { 187 return(EINVAL); /* not a kernel thread */ 188 } 189 } 190 191 void 192 kproc_suspend_loop(void) 193 { 194 struct thread *td = curthread; 195 196 if (td->td_flags & TDF_STOPREQ) { 197 lwkt_gettoken(&kpsus_token); 198 td->td_flags &= ~TDF_STOPREQ; 199 while ((td->td_flags & TDF_WAKEREQ) == 0) { 200 wakeup(td); 201 tsleep(td, 0, "kpsusp", 0); 202 } 203 td->td_flags &= ~TDF_WAKEREQ; 204 wakeup(td); 205 lwkt_reltoken(&kpsus_token); 206 } 207 } 208 209