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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: src/sys/kern/kern_kthread.c,v 1.47 2008/08/03 21:07:19 antoine Exp $");
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kthread.h>
33 #include <sys/lock.h>
34 #include <sys/mutex.h>
35 #include <sys/proc.h>
36 #include <sys/resourcevar.h>
37 #include <sys/signalvar.h>
38 #include <sys/sx.h>
39 #include <sys/unistd.h>
40 #include <sys/wait.h>
41 #include <sys/sched.h>
42 #include <vm/vm.h>
43 #include <vm/vm_extern.h>
44
45 #include <machine/stdarg.h>
46
47 /*
48 * Start a kernel process. This is called after a fork() call in
49 * mi_startup() in the file kern/init_main.c.
50 *
51 * This function is used to start "internal" daemons and intended
52 * to be called from SYSINIT().
53 */
54 void
55 kproc_start(udata)
56 const void *udata;
57 {
58 const struct kproc_desc *kp = udata;
59 int error;
60
61 error = kproc_create((void (*)(void *))kp->func, NULL,
62 kp->global_procpp, 0, 0, "%s", kp->arg0);
63 if (error)
64 panic("kproc_start: %s: error %d", kp->arg0, error);
65 }
66
67 /*
68 * Create a kernel process/thread/whatever. It shares its address space
69 * with proc0 - ie: kernel only.
70 *
71 * func is the function to start.
72 * arg is the parameter to pass to function on first startup.
73 * newpp is the return value pointing to the thread's struct proc.
74 * flags are flags to fork1 (in unistd.h)
75 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
76 */
77 int
78 kproc_create(void (*func)(void *), void *arg,
79 struct proc **newpp, int flags, int pages, const char *fmt, ...)
80 {
81 int error;
82 va_list ap;
83 struct thread *td;
84 struct proc *p2;
85
86 if (!proc0.p_stats)
87 panic("kproc_create called too soon");
88
89 error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags,
90 pages, &p2);
91 if (error)
92 return error;
93
94 /* save a global descriptor, if desired */
95 if (newpp != NULL)
96 *newpp = p2;
97
98 /* this is a non-swapped system process */
99 PROC_LOCK(p2);
100 td = FIRST_THREAD_IN_PROC(p2);
101 p2->p_flag |= P_SYSTEM | P_KTHREAD;
102 td->td_pflags |= TDP_KTHREAD;
103 mtx_lock(&p2->p_sigacts->ps_mtx);
104 p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
105 mtx_unlock(&p2->p_sigacts->ps_mtx);
106 PROC_UNLOCK(p2);
107
108 /* set up arg0 for 'ps', et al */
109 va_start(ap, fmt);
110 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
111 va_end(ap);
112 /* set up arg0 for 'ps', et al */
113 va_start(ap, fmt);
114 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
115 va_end(ap);
116
117 /* call the processes' main()... */
118 cpu_set_fork_handler(td, func, arg);
119 TD_SET_CAN_RUN(td);
120
121 /* Delay putting it on the run queue until now. */
122 if (!(flags & RFSTOPPED)) {
123 thread_lock(td);
124 sched_add(td, SRQ_BORING);
125 thread_unlock(td);
126 }
127
128 return 0;
129 }
130
131 void
132 kproc_exit(int ecode)
133 {
134 struct thread *td;
135 struct proc *p;
136
137 td = curthread;
138 p = td->td_proc;
139
140 /*
141 * Reparent curthread from proc0 to init so that the zombie
142 * is harvested.
143 */
144 sx_xlock(&proctree_lock);
145 PROC_LOCK(p);
146 proc_reparent(p, initproc);
147 PROC_UNLOCK(p);
148 sx_xunlock(&proctree_lock);
149
150 /*
151 * Wakeup anyone waiting for us to exit.
152 */
153 wakeup(p);
154
155 /* Buh-bye! */
156 exit1(td, W_EXITCODE(ecode, 0));
157 }
158
159 /*
160 * Advise a kernel process to suspend (or resume) in its main loop.
161 * Participation is voluntary.
162 */
163 int
164 kproc_suspend(struct proc *p, int timo)
165 {
166 /*
167 * Make sure this is indeed a system process and we can safely
168 * use the p_siglist field.
169 */
170 PROC_LOCK(p);
171 if ((p->p_flag & P_KTHREAD) == 0) {
172 PROC_UNLOCK(p);
173 return (EINVAL);
174 }
175 SIGADDSET(p->p_siglist, SIGSTOP);
176 wakeup(p);
177 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo);
178 }
179
180 int
181 kproc_resume(struct proc *p)
182 {
183 /*
184 * Make sure this is indeed a system process and we can safely
185 * use the p_siglist field.
186 */
187 PROC_LOCK(p);
188 if ((p->p_flag & P_KTHREAD) == 0) {
189 PROC_UNLOCK(p);
190 return (EINVAL);
191 }
192 SIGDELSET(p->p_siglist, SIGSTOP);
193 PROC_UNLOCK(p);
194 wakeup(&p->p_siglist);
195 return (0);
196 }
197
198 void
199 kproc_suspend_check(struct proc *p)
200 {
201 PROC_LOCK(p);
202 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
203 wakeup(&p->p_siglist);
204 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
205 }
206 PROC_UNLOCK(p);
207 }
208
209
210 /*
211 * Start a kernel thread.
212 *
213 * This function is used to start "internal" daemons and intended
214 * to be called from SYSINIT().
215 */
216
217 void
218 kthread_start(udata)
219 const void *udata;
220 {
221 const struct kthread_desc *kp = udata;
222 int error;
223
224 error = kthread_add((void (*)(void *))kp->func, NULL,
225 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
226 if (error)
227 panic("kthread_start: %s: error %d", kp->arg0, error);
228 }
229
230 /*
231 * Create a kernel thread. It shares its address space
232 * with proc0 - ie: kernel only.
233 *
234 * func is the function to start.
235 * arg is the parameter to pass to function on first startup.
236 * newtdp is the return value pointing to the thread's struct thread.
237 * ** XXX fix this --> flags are flags to fork1 (in unistd.h)
238 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
239 */
240 int
241 kthread_add(void (*func)(void *), void *arg, struct proc *p,
242 struct thread **newtdp, int flags, int pages, const char *fmt, ...)
243 {
244 va_list ap;
245 struct thread *newtd, *oldtd;
246
247 if (!proc0.p_stats)
248 panic("kthread_add called too soon");
249
250 /* If no process supplied, put it on proc0 */
251 if (p == NULL) {
252 p = &proc0;
253 oldtd = &thread0;
254 } else {
255 oldtd = FIRST_THREAD_IN_PROC(p);
256 }
257
258 /* Initialize our new td */
259 newtd = thread_alloc();
260 if (newtd == NULL)
261 return (ENOMEM);
262
263 bzero(&newtd->td_startzero,
264 __rangeof(struct thread, td_startzero, td_endzero));
265 /* XXX check if we should zero. */
266 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
267 __rangeof(struct thread, td_startcopy, td_endcopy));
268
269 /* set up arg0 for 'ps', et al */
270 va_start(ap, fmt);
271 vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap);
272 va_end(ap);
273
274 newtd->td_proc = p; /* needed for cpu_set_upcall */
275
276 /* XXX optimise this probably? */
277 /* On x86 (and probably the others too) it is way too full of junk */
278 /* Needs a better name */
279 cpu_set_upcall(newtd, oldtd);
280 /* put the designated function(arg) as the resume context */
281 cpu_set_fork_handler(newtd, func, arg);
282
283 newtd->td_pflags |= TDP_KTHREAD;
284 newtd->td_ucred = crhold(p->p_ucred);
285 /* Allocate and switch to an alternate kstack if specified. */
286 if (pages != 0)
287 vm_thread_new_altkstack(newtd, pages);
288
289 /* this code almost the same as create_thread() in kern_thr.c */
290 PROC_LOCK(p);
291 p->p_flag |= P_HADTHREADS;
292 newtd->td_sigmask = oldtd->td_sigmask; /* XXX dubious */
293 thread_link(newtd, p);
294 thread_lock(oldtd);
295 /* let the scheduler know about these things. */
296 sched_fork_thread(oldtd, newtd);
297 TD_SET_CAN_RUN(newtd);
298 thread_unlock(oldtd);
299 PROC_UNLOCK(p);
300
301
302 /* Delay putting it on the run queue until now. */
303 if (!(flags & RFSTOPPED)) {
304 thread_lock(newtd);
305 sched_add(newtd, SRQ_BORING);
306 thread_unlock(newtd);
307 }
308 if (newtdp)
309 *newtdp = newtd;
310 return 0;
311 }
312
313 void
314 kthread_exit(void)
315 {
316 struct proc *p;
317
318 /* A module may be waiting for us to exit. */
319 wakeup(curthread);
320
321 /*
322 * We could rely on thread_exit to call exit1() but
323 * there is extra work that needs to be done
324 */
325 if (curthread->td_proc->p_numthreads == 1)
326 kproc_exit(0); /* never returns */
327
328 p = curthread->td_proc;
329 PROC_LOCK(p);
330 PROC_SLOCK(p);
331 thread_exit();
332 }
333
334 /*
335 * Advise a kernel process to suspend (or resume) in its main loop.
336 * Participation is voluntary.
337 */
338 int
339 kthread_suspend(struct thread *td, int timo)
340 {
341 if ((td->td_pflags & TDP_KTHREAD) == 0) {
342 return (EINVAL);
343 }
344 thread_lock(td);
345 td->td_flags |= TDF_KTH_SUSP;
346 thread_unlock(td);
347 /*
348 * If it's stopped for some other reason,
349 * kick it to notice our request
350 * or we'll end up timing out
351 */
352 wakeup(td); /* traditional place for kernel threads to sleep on */ /* XXX ?? */
353 return (tsleep(&td->td_flags, PPAUSE | PDROP, "suspkt", timo));
354 }
355
356 /*
357 * let the kthread it can keep going again.
358 */
359 int
360 kthread_resume(struct thread *td)
361 {
362 if ((td->td_pflags & TDP_KTHREAD) == 0) {
363 return (EINVAL);
364 }
365 thread_lock(td);
366 td->td_flags &= ~TDF_KTH_SUSP;
367 thread_unlock(td);
368 wakeup(&td->td_name);
369 return (0);
370 }
371
372 /*
373 * Used by the thread to poll as to whether it should yield/sleep
374 * and notify the caller that is has happened.
375 */
376 void
377 kthread_suspend_check(struct thread *td)
378 {
379 while (td->td_flags & TDF_KTH_SUSP) {
380 /*
381 * let the caller know we got the message then sleep
382 */
383 wakeup(&td->td_flags);
384 tsleep(&td->td_name, PPAUSE, "ktsusp", 0);
385 }
386 }
387
388 int
389 kproc_kthread_add(void (*func)(void *), void *arg,
390 struct proc **procptr, struct thread **tdptr,
391 int flags, int pages, char * procname, const char *fmt, ...)
392 {
393 int error;
394 va_list ap;
395 char buf[100];
396 struct thread *td;
397
398 if (*procptr == 0) {
399 error = kproc_create(func, arg,
400 procptr, flags, pages, "%s", procname);
401 if (error)
402 return (error);
403 td = FIRST_THREAD_IN_PROC(*procptr);
404 if (tdptr)
405 *tdptr = td;
406 va_start(ap, fmt);
407 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
408 va_end(ap);
409 return (0);
410 }
411 va_start(ap, fmt);
412 vsnprintf(buf, sizeof(buf), fmt, ap);
413 va_end(ap);
414 error = kthread_add(func, arg, *procptr,
415 tdptr, flags, pages, "%s", buf);
416 return (error);
417 }
418
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