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 1.10 2004/07/29 09:02:33 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 /* 43 * Create a kernel process/thread/whatever. It shares it's address space 44 * with proc0 - ie: kernel only. 5.x compatible. 45 * 46 * NOTE! By default kthreads are created with the MP lock held. A 47 * thread which does not require the MP lock should release it by calling 48 * rel_mplock() at the start of the new thread. 49 */ 50 int 51 kthread_create(void (*func)(void *), void *arg, 52 struct thread **tdp, const char *fmt, ...) 53 { 54 thread_t td; 55 __va_list ap; 56 57 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, -1); 58 if (tdp) 59 *tdp = td; 60 cpu_set_thread_handler(td, kthread_exit, func, arg); 61 td->td_flags |= TDF_VERBOSE; 62 #ifdef SMP 63 td->td_mpcount = 1; 64 #endif 65 66 /* 67 * Set up arg0 for 'ps' etc 68 */ 69 __va_start(ap, fmt); 70 vsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 71 __va_end(ap); 72 73 /* 74 * Schedule the thread to run 75 */ 76 lwkt_schedule(td); 77 return 0; 78 } 79 80 /* 81 * Same as kthread_create() but you can specify a custom stack size. 82 */ 83 int 84 kthread_create_stk(void (*func)(void *), void *arg, 85 struct thread **tdp, int stksize, const char *fmt, ...) 86 { 87 thread_t td; 88 __va_list ap; 89 90 td = lwkt_alloc_thread(NULL, stksize, -1); 91 if (tdp) 92 *tdp = td; 93 cpu_set_thread_handler(td, kthread_exit, func, arg); 94 td->td_flags |= TDF_VERBOSE; 95 #ifdef SMP 96 td->td_mpcount = 1; 97 #endif 98 __va_start(ap, fmt); 99 vsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 100 __va_end(ap); 101 102 lwkt_schedule(td); 103 return 0; 104 } 105 106 /* 107 * Destroy an LWKT thread. Warning! This function is not called when 108 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 109 * uses a different reaping mechanism. 110 * 111 * XXX duplicates lwkt_exit() 112 */ 113 void 114 kthread_exit(void) 115 { 116 lwkt_exit(); 117 } 118 119 120 /* 121 * Start a kernel process. This is called after a fork() call in 122 * mi_startup() in the file kern/init_main.c. 123 * 124 * This function is used to start "internal" daemons and intended 125 * to be called from SYSINIT(). 126 */ 127 void 128 kproc_start(udata) 129 const void *udata; 130 { 131 const struct kproc_desc *kp = udata; 132 int error; 133 134 error = kthread_create((void (*)(void *))kp->func, NULL, 135 kp->global_threadpp, kp->arg0); 136 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 137 if (error) 138 panic("kproc_start: %s: error %d", kp->arg0, error); 139 } 140 141 /* 142 * Advise a kernel process to suspend (or resume) in its main loop. 143 * Participation is voluntary. 144 */ 145 int 146 suspend_kproc(struct thread *td, int timo) 147 { 148 if (td->td_proc == NULL) { 149 td->td_flags |= TDF_STOPREQ; /* request thread pause */ 150 wakeup(td); 151 while (td->td_flags & TDF_STOPREQ) { 152 int error = tsleep(td, 0, "suspkp", timo); 153 if (error == EWOULDBLOCK) 154 break; 155 } 156 td->td_flags &= ~TDF_STOPREQ; 157 return(0); 158 } else { 159 return(EINVAL); /* not a kernel thread */ 160 } 161 } 162 163 void 164 kproc_suspend_loop(void) 165 { 166 struct thread *td = curthread; 167 168 if (td->td_flags & TDF_STOPREQ) { 169 td->td_flags &= ~TDF_STOPREQ; 170 while ((td->td_flags & TDF_WAKEREQ) == 0) { 171 wakeup(td); 172 tsleep(td, 0, "kpsusp", 0); 173 } 174 td->td_flags &= ~TDF_WAKEREQ; 175 wakeup(td); 176 } 177 } 178 179