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 1.12 2005/11/22 08:41:03 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, TDF_VERBOSE); 58 if (tdp) 59 *tdp = td; 60 cpu_set_thread_handler(td, kthread_exit, func, arg); 61 #ifdef SMP 62 KKASSERT(td->td_mpcount == 1); 63 #endif 64 65 /* 66 * Set up arg0 for 'ps' etc 67 */ 68 __va_start(ap, fmt); 69 vsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 70 __va_end(ap); 71 72 /* 73 * Schedule the thread to run 74 */ 75 lwkt_schedule(td); 76 return 0; 77 } 78 79 /* 80 * Same as kthread_create() but you can specify a custom stack size. 81 */ 82 int 83 kthread_create_stk(void (*func)(void *), void *arg, 84 struct thread **tdp, int stksize, const char *fmt, ...) 85 { 86 thread_t td; 87 __va_list ap; 88 89 td = lwkt_alloc_thread(NULL, stksize, -1, TDF_VERBOSE); 90 if (tdp) 91 *tdp = td; 92 cpu_set_thread_handler(td, kthread_exit, func, arg); 93 #ifdef SMP 94 KKASSERT(td->td_mpcount == 1); 95 #endif 96 __va_start(ap, fmt); 97 vsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 98 __va_end(ap); 99 100 lwkt_schedule(td); 101 return 0; 102 } 103 104 /* 105 * Destroy an LWKT thread. Warning! This function is not called when 106 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 107 * uses a different reaping mechanism. 108 * 109 * XXX duplicates lwkt_exit() 110 */ 111 void 112 kthread_exit(void) 113 { 114 lwkt_exit(); 115 } 116 117 118 /* 119 * Start a kernel process. This is called after a fork() call in 120 * mi_startup() in the file kern/init_main.c. 121 * 122 * This function is used to start "internal" daemons and intended 123 * to be called from SYSINIT(). 124 */ 125 void 126 kproc_start(const void *udata) 127 { 128 const struct kproc_desc *kp = udata; 129 int error; 130 131 error = kthread_create((void (*)(void *))kp->func, NULL, 132 kp->global_threadpp, kp->arg0); 133 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 134 if (error) 135 panic("kproc_start: %s: error %d", kp->arg0, error); 136 } 137 138 /* 139 * Advise a kernel process to suspend (or resume) in its main loop. 140 * Participation is voluntary. 141 */ 142 int 143 suspend_kproc(struct thread *td, int timo) 144 { 145 if (td->td_proc == NULL) { 146 td->td_flags |= TDF_STOPREQ; /* request thread pause */ 147 wakeup(td); 148 while (td->td_flags & TDF_STOPREQ) { 149 int error = tsleep(td, 0, "suspkp", timo); 150 if (error == EWOULDBLOCK) 151 break; 152 } 153 td->td_flags &= ~TDF_STOPREQ; 154 return(0); 155 } else { 156 return(EINVAL); /* not a kernel thread */ 157 } 158 } 159 160 void 161 kproc_suspend_loop(void) 162 { 163 struct thread *td = curthread; 164 165 if (td->td_flags & TDF_STOPREQ) { 166 td->td_flags &= ~TDF_STOPREQ; 167 while ((td->td_flags & TDF_WAKEREQ) == 0) { 168 wakeup(td); 169 tsleep(td, 0, "kpsusp", 0); 170 } 171 td->td_flags &= ~TDF_WAKEREQ; 172 wakeup(td); 173 } 174 } 175 176