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 kernel process/thread/whatever. It shares it's address space 47 * with proc0 - ie: kernel only. 5.x compatible. 48 * 49 * All kthreads are created as MPSAFE threads. 50 */ 51 int 52 kthread_create(void (*func)(void *), void *arg, 53 struct thread **tdp, const char *fmt, ...) 54 { 55 thread_t td; 56 __va_list ap; 57 58 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, -1, TDF_VERBOSE); 59 if (tdp) 60 *tdp = td; 61 cpu_set_thread_handler(td, kthread_exit, func, arg); 62 63 /* 64 * Set up arg0 for 'ps' etc 65 */ 66 __va_start(ap, fmt); 67 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 68 __va_end(ap); 69 70 td->td_ucred = crhold(proc0.p_ucred); 71 72 /* 73 * Schedule the thread to run 74 */ 75 lwkt_schedule(td); 76 return 0; 77 } 78 79 int 80 kthread_create_cpu(void (*func)(void *), void *arg, 81 struct thread **tdp, int cpu, const char *fmt, ...) 82 { 83 thread_t td; 84 __va_list ap; 85 86 td = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, cpu, TDF_VERBOSE); 87 if (tdp) 88 *tdp = td; 89 cpu_set_thread_handler(td, kthread_exit, func, arg); 90 91 /* 92 * Set up arg0 for 'ps' etc 93 */ 94 __va_start(ap, fmt); 95 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 96 __va_end(ap); 97 98 td->td_ucred = crhold(proc0.p_ucred); 99 100 /* 101 * Schedule the thread to run 102 */ 103 lwkt_schedule(td); 104 return 0; 105 } 106 107 #if 0 108 /* 109 * Same as kthread_create() but you can specify a custom stack size. 110 */ 111 int 112 kthread_create_stk(void (*func)(void *), void *arg, 113 struct thread **tdp, int stksize, const char *fmt, ...) 114 { 115 thread_t td; 116 __va_list ap; 117 118 td = lwkt_alloc_thread(NULL, stksize, -1, TDF_VERBOSE); 119 if (tdp) 120 *tdp = td; 121 cpu_set_thread_handler(td, kthread_exit, func, arg); 122 123 __va_start(ap, fmt); 124 kvsnprintf(td->td_comm, sizeof(td->td_comm), fmt, ap); 125 __va_end(ap); 126 127 lwkt_schedule(td); 128 return 0; 129 } 130 #endif 131 132 /* 133 * Destroy an LWKT thread. Warning! This function is not called when 134 * a process exits, cpu_proc_exit() directly calls cpu_thread_exit() and 135 * uses a different reaping mechanism. 136 * 137 * XXX duplicates lwkt_exit() 138 */ 139 void 140 kthread_exit(void) 141 { 142 lwkt_exit(); 143 } 144 145 /* 146 * Start a kernel process. This is called after a fork() call in 147 * mi_startup() in the file kern/init_main.c. 148 * 149 * This function is used to start "internal" daemons and intended 150 * to be called from SYSINIT(). 151 * 152 * These threads are created MPSAFE. 153 */ 154 void 155 kproc_start(const void *udata) 156 { 157 const struct kproc_desc *kp = udata; 158 int error; 159 160 error = kthread_create((void (*)(void *))kp->func, NULL, 161 kp->global_threadpp, kp->arg0); 162 lwkt_setpri(*kp->global_threadpp, TDPRI_KERN_DAEMON); 163 if (error) 164 panic("kproc_start: %s: error %d", kp->arg0, error); 165 } 166 167 /* 168 * Advise a kernel process to suspend (or resume) in its main loop. 169 * Participation is voluntary. 170 */ 171 int 172 suspend_kproc(struct thread *td, int timo) 173 { 174 if (td->td_proc == NULL) { 175 lwkt_gettoken(&kpsus_token); 176 /* request thread pause */ 177 atomic_set_int(&td->td_mpflags, TDF_MP_STOPREQ); 178 wakeup(td); 179 while (td->td_mpflags & TDF_MP_STOPREQ) { 180 int error = tsleep(td, 0, "suspkp", timo); 181 if (error == EWOULDBLOCK) 182 break; 183 } 184 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 185 lwkt_reltoken(&kpsus_token); 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_mpflags & TDF_MP_STOPREQ) { 198 lwkt_gettoken(&kpsus_token); 199 atomic_clear_int(&td->td_mpflags, TDF_MP_STOPREQ); 200 while ((td->td_mpflags & TDF_MP_WAKEREQ) == 0) { 201 wakeup(td); 202 tsleep(td, 0, "kpsusp", 0); 203 } 204 atomic_clear_int(&td->td_mpflags, TDF_MP_WAKEREQ); 205 wakeup(td); 206 lwkt_reltoken(&kpsus_token); 207 } 208 } 209 210