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 /* 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 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 #ifdef SMP 93 KKASSERT(td->td_mpcount == 1); 94 #endif 95 96 /* 97 * Set up arg0 for 'ps' etc 98 */ 99 __va_start(ap, fmt); 100 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 101 __va_end(ap); 102 103 td->td_ucred = crhold(proc0.p_ucred); 104 105 /* 106 * Schedule the thread to run 107 */ 108 lwkt_schedule(td); 109 return 0; 110 } 111 112 /* 113 * Same as kthread_create() but you can specify a custom stack size. 114 */ 115 int 116 kthread_create_stk(void (*func)(void *), void *arg, 117 struct thread **tdp, int stksize, const char *fmt, ...) 118 { 119 thread_t td; 120 __va_list ap; 121 122 td = lwkt_alloc_thread(NULL, stksize, -1, TDF_VERBOSE); 123 if (tdp) 124 *tdp = td; 125 cpu_set_thread_handler(td, kthread_exit, func, arg); 126 #ifdef SMP 127 KKASSERT(td->td_mpcount == 1); 128 #endif 129 __va_start(ap, fmt); 130 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 131 __va_end(ap); 132 133 lwkt_schedule(td); 134 return 0; 135 } 136 137 /* 138 * Destroy an LWKT thread. Warning! This function is not called when 139 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 140 * uses a different reaping mechanism. 141 * 142 * XXX duplicates lwkt_exit() 143 */ 144 void 145 kthread_exit(void) 146 { 147 lwkt_exit(); 148 } 149 150 /* 151 * Start a kernel process. This is called after a fork() call in 152 * mi_startup() in the file kern/init_main.c. 153 * 154 * This function is used to start "internal" daemons and intended 155 * to be called from SYSINIT(). 156 */ 157 void 158 kproc_start(const void *udata) 159 { 160 const struct kproc_desc *kp = udata; 161 int error; 162 163 error = kthread_create((void (*)(void *))kp->func, NULL, 164 kp->global_threadpp, kp->arg0); 165 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 166 if (error) 167 panic("kproc_start: %s: error %d", kp->arg0, error); 168 } 169 170 /* 171 * Advise a kernel process to suspend (or resume) in its main loop. 172 * Participation is voluntary. 173 */ 174 int 175 suspend_kproc(struct thread *td, int timo) 176 { 177 if (td->td_proc == NULL) { 178 td->td_flags |= TDF_STOPREQ; /* request thread pause */ 179 wakeup(td); 180 while (td->td_flags & TDF_STOPREQ) { 181 int error = tsleep(td, 0, "suspkp", timo); 182 if (error == EWOULDBLOCK) 183 break; 184 } 185 td->td_flags &= ~TDF_STOPREQ; 186 return(0); 187 } else { 188 return(EINVAL); /* not a kernel thread */ 189 } 190 } 191 192 void 193 kproc_suspend_loop(void) 194 { 195 struct thread *td = curthread; 196 197 if (td->td_flags & TDF_STOPREQ) { 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 } 206 } 207 208