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 static struct lwkt_token kpsus_token = LWKT_TOKEN_INITIALIZER(kpsus_token); 43 44 45 /* 46 * Create a new lightweight kernel thread. 47 */ 48 static int 49 _kthread_create(void (*func)(void *), void *arg, 50 struct thread **tdp, int cpu, const char *fmt, ...) 51 { 52 thread_t td; 53 __va_list ap; 54 int flags = 0; 55 56 if (bootverbose) 57 atomic_set_int(&flags, TDF_VERBOSE); 58 59 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, cpu, flags); 60 if (tdp) 61 *tdp = td; 62 cpu_set_thread_handler(td, kthread_exit, func, arg); 63 64 /* 65 * Set up arg0 for 'ps' etc 66 */ 67 __va_start(ap, fmt); 68 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 69 __va_end(ap); 70 71 td->td_ucred = crhold(proc0.p_ucred); 72 73 /* 74 * Schedule the thread to run 75 */ 76 lwkt_schedule(td); 77 78 return 0; 79 } 80 81 /* 82 * Creates a lwkt. No CPU preference. 83 */ 84 int 85 kthread_create(void (*func)(void *), void *arg, 86 struct thread **tdp, const char *fmt, ...) 87 { 88 return _kthread_create(func, arg, tdp, -1, fmt); 89 } 90 91 /* 92 * Creates a lwkt and schedule it to run in a specific CPU. 93 * 94 */ 95 int 96 kthread_create_cpu(void (*func)(void *), void *arg, 97 struct thread **tdp, int cpu, const char *fmt, ...) 98 { 99 return _kthread_create(func, arg, tdp, cpu, fmt); 100 } 101 102 #if 0 103 /* 104 * Same as kthread_create() but you can specify a custom stack size. 105 */ 106 int 107 kthread_create_stk(void (*func)(void *), void *arg, 108 struct thread **tdp, int stksize, const char *fmt, ...) 109 { 110 thread_t td; 111 __va_list ap; 112 113 td = lwkt_alloc_thread(NULL, stksize, -1, TDF_VERBOSE); 114 if (tdp) 115 *tdp = td; 116 cpu_set_thread_handler(td, kthread_exit, func, arg); 117 118 __va_start(ap, fmt); 119 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 120 __va_end(ap); 121 122 lwkt_schedule(td); 123 return 0; 124 } 125 #endif 126 127 /* 128 * Destroy an LWKT thread. Warning! This function is not called when 129 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 130 * uses a different reaping mechanism. 131 * 132 * XXX duplicates lwkt_exit() 133 */ 134 void 135 kthread_exit(void) 136 { 137 lwkt_exit(); 138 } 139 140 /* 141 * Start a kernel process. This is called after a fork() call in 142 * mi_startup() in the file kern/init_main.c. 143 * 144 * This function is used to start "internal" daemons and intended 145 * to be called from SYSINIT(). 146 * 147 * These threads are created MPSAFE. 148 */ 149 void 150 kproc_start(const void *udata) 151 { 152 const struct kproc_desc *kp = udata; 153 int error; 154 155 error = kthread_create((void (*)(void *))kp->func, NULL, 156 kp->global_threadpp, kp->arg0); 157 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 158 if (error) 159 panic("kproc_start: %s: error %d", kp->arg0, error); 160 } 161 162 /* 163 * Advise a kernel process to suspend (or resume) in its main loop. 164 * Participation is voluntary. 165 */ 166 int 167 suspend_kproc(struct thread *td, int timo) 168 { 169 if (td->td_proc == NULL) { 170 lwkt_gettoken(&kpsus_token); 171 /* request thread pause */ 172 atomic_set_int(&td->td_mpflags, TDF_MP_STOPREQ); 173 wakeup(td); 174 while (td->td_mpflags & TDF_MP_STOPREQ) { 175 int error = tsleep(td, 0, "suspkp", timo); 176 if (error == EWOULDBLOCK) 177 break; 178 } 179 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 180 lwkt_reltoken(&kpsus_token); 181 return(0); 182 } else { 183 return(EINVAL); /* not a kernel thread */ 184 } 185 } 186 187 void 188 kproc_suspend_loop(void) 189 { 190 struct thread *td = curthread; 191 192 if (td->td_mpflags & TDF_MP_STOPREQ) { 193 lwkt_gettoken(&kpsus_token); 194 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 195 while ((td->td_mpflags & TDF_MP_WAKEREQ) == 0) { 196 wakeup(td); 197 tsleep(td, 0, "kpsusp", 0); 198 } 199 atomic_clear_int(&td->td_mpflags, TDF_MP_WAKEREQ); 200 wakeup(td); 201 lwkt_reltoken(&kpsus_token); 202 } 203 } 204 205