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 1.9 2003/07/19 21:14:38 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 * Start a kernel process. This is called after a fork() call in 44 * mi_startup() in the file kern/init_main.c. 45 * 46 * This function is used to start "internal" daemons and intended 47 * to be called from SYSINIT(). 48 */ 49 void 50 kproc_start(udata) 51 const void *udata; 52 { 53 const struct kproc_desc *kp = udata; 54 int error; 55 56 error = kthread_create((void (*)(void *))kp->func, NULL, 57 kp->global_threadpp, kp->arg0); 58 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 59 if (error) 60 panic("kproc_start: %s: error %d", kp->arg0, error); 61 } 62 63 /* 64 * Advise a kernel process to suspend (or resume) in its main loop. 65 * Participation is voluntary. 66 */ 67 int 68 suspend_kproc(struct thread *td, int timo) 69 { 70 if (td->td_proc == NULL) { 71 td->td_flags |= TDF_STOPREQ; /* request thread pause */ 72 wakeup(td); 73 while (td->td_flags & TDF_STOPREQ) { 74 int error = tsleep(td, 0, "suspkp", timo); 75 if (error == EWOULDBLOCK) 76 break; 77 } 78 td->td_flags &= ~TDF_STOPREQ; 79 return(0); 80 } else { 81 return(EINVAL); /* not a kernel thread */ 82 } 83 } 84 85 void 86 kproc_suspend_loop(void) 87 { 88 struct thread *td = curthread; 89 90 if (td->td_flags & TDF_STOPREQ) { 91 td->td_flags &= ~TDF_STOPREQ; 92 while ((td->td_flags & TDF_WAKEREQ) == 0) { 93 wakeup(td); 94 tsleep(td, 0, "kpsusp", 0); 95 } 96 td->td_flags &= ~TDF_WAKEREQ; 97 wakeup(td); 98 } 99 } 100 101