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: releng/10.1/sys/kern/kern_kthread.c 254457 2013-08-17 17:02:43Z bryanv $");
29
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/cpuset.h>
33 #include <sys/kthread.h>
34 #include <sys/lock.h>
35 #include <sys/mutex.h>
36 #include <sys/proc.h>
37 #include <sys/resourcevar.h>
38 #include <sys/rwlock.h>
39 #include <sys/signalvar.h>
40 #include <sys/sx.h>
41 #include <sys/unistd.h>
42 #include <sys/wait.h>
43 #include <sys/sched.h>
44 #include <vm/vm.h>
45 #include <vm/vm_extern.h>
46
47 #include <machine/stdarg.h>
48
49 /*
50 * Start a kernel process. This is called after a fork() call in
51 * mi_startup() in the file kern/init_main.c.
52 *
53 * This function is used to start "internal" daemons and intended
54 * to be called from SYSINIT().
55 */
56 void
57 kproc_start(udata)
58 const void *udata;
59 {
60 const struct kproc_desc *kp = udata;
61 int error;
62
63 error = kproc_create((void (*)(void *))kp->func, NULL,
64 kp->global_procpp, 0, 0, "%s", kp->arg0);
65 if (error)
66 panic("kproc_start: %s: error %d", kp->arg0, error);
67 }
68
69 /*
70 * Create a kernel process/thread/whatever. It shares its address space
71 * with proc0 - ie: kernel only.
72 *
73 * func is the function to start.
74 * arg is the parameter to pass to function on first startup.
75 * newpp is the return value pointing to the thread's struct proc.
76 * flags are flags to fork1 (in unistd.h)
77 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
78 */
79 int
80 kproc_create(void (*func)(void *), void *arg,
81 struct proc **newpp, int flags, int pages, const char *fmt, ...)
82 {
83 int error;
84 va_list ap;
85 struct thread *td;
86 struct proc *p2;
87
88 if (!proc0.p_stats)
89 panic("kproc_create called too soon");
90
91 error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags,
92 pages, &p2, NULL, 0);
93 if (error)
94 return error;
95
96 /* save a global descriptor, if desired */
97 if (newpp != NULL)
98 *newpp = p2;
99
100 /* this is a non-swapped system process */
101 PROC_LOCK(p2);
102 td = FIRST_THREAD_IN_PROC(p2);
103 p2->p_flag |= P_SYSTEM | P_KTHREAD;
104 td->td_pflags |= TDP_KTHREAD;
105 mtx_lock(&p2->p_sigacts->ps_mtx);
106 p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
107 mtx_unlock(&p2->p_sigacts->ps_mtx);
108 PROC_UNLOCK(p2);
109
110 /* set up arg0 for 'ps', et al */
111 va_start(ap, fmt);
112 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
113 va_end(ap);
114 /* set up arg0 for 'ps', et al */
115 va_start(ap, fmt);
116 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
117 va_end(ap);
118 #ifdef KTR
119 sched_clear_tdname(td);
120 #endif
121
122 /* call the processes' main()... */
123 cpu_set_fork_handler(td, func, arg);
124
125 /* Avoid inheriting affinity from a random parent. */
126 cpuset_setthread(td->td_tid, cpuset_root);
127 thread_lock(td);
128 TD_SET_CAN_RUN(td);
129 sched_prio(td, PVM);
130 sched_user_prio(td, PUSER);
131
132 /* Delay putting it on the run queue until now. */
133 if (!(flags & RFSTOPPED))
134 sched_add(td, SRQ_BORING);
135 thread_unlock(td);
136
137 return 0;
138 }
139
140 void
141 kproc_exit(int ecode)
142 {
143 struct thread *td;
144 struct proc *p;
145
146 td = curthread;
147 p = td->td_proc;
148
149 /*
150 * Reparent curthread from proc0 to init so that the zombie
151 * is harvested.
152 */
153 sx_xlock(&proctree_lock);
154 PROC_LOCK(p);
155 proc_reparent(p, initproc);
156 PROC_UNLOCK(p);
157 sx_xunlock(&proctree_lock);
158
159 /*
160 * Wakeup anyone waiting for us to exit.
161 */
162 wakeup(p);
163
164 /* Buh-bye! */
165 exit1(td, W_EXITCODE(ecode, 0));
166 }
167
168 /*
169 * Advise a kernel process to suspend (or resume) in its main loop.
170 * Participation is voluntary.
171 */
172 int
173 kproc_suspend(struct proc *p, int timo)
174 {
175 /*
176 * Make sure this is indeed a system process and we can safely
177 * use the p_siglist field.
178 */
179 PROC_LOCK(p);
180 if ((p->p_flag & P_KTHREAD) == 0) {
181 PROC_UNLOCK(p);
182 return (EINVAL);
183 }
184 SIGADDSET(p->p_siglist, SIGSTOP);
185 wakeup(p);
186 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo);
187 }
188
189 int
190 kproc_resume(struct proc *p)
191 {
192 /*
193 * Make sure this is indeed a system process and we can safely
194 * use the p_siglist field.
195 */
196 PROC_LOCK(p);
197 if ((p->p_flag & P_KTHREAD) == 0) {
198 PROC_UNLOCK(p);
199 return (EINVAL);
200 }
201 SIGDELSET(p->p_siglist, SIGSTOP);
202 PROC_UNLOCK(p);
203 wakeup(&p->p_siglist);
204 return (0);
205 }
206
207 void
208 kproc_suspend_check(struct proc *p)
209 {
210 PROC_LOCK(p);
211 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
212 wakeup(&p->p_siglist);
213 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
214 }
215 PROC_UNLOCK(p);
216 }
217
218
219 /*
220 * Start a kernel thread.
221 *
222 * This function is used to start "internal" daemons and intended
223 * to be called from SYSINIT().
224 */
225
226 void
227 kthread_start(udata)
228 const void *udata;
229 {
230 const struct kthread_desc *kp = udata;
231 int error;
232
233 error = kthread_add((void (*)(void *))kp->func, NULL,
234 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
235 if (error)
236 panic("kthread_start: %s: error %d", kp->arg0, error);
237 }
238
239 /*
240 * Create a kernel thread. It shares its address space
241 * with proc0 - ie: kernel only.
242 *
243 * func is the function to start.
244 * arg is the parameter to pass to function on first startup.
245 * newtdp is the return value pointing to the thread's struct thread.
246 * ** XXX fix this --> flags are flags to fork1 (in unistd.h)
247 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
248 */
249 int
250 kthread_add(void (*func)(void *), void *arg, struct proc *p,
251 struct thread **newtdp, int flags, int pages, const char *fmt, ...)
252 {
253 va_list ap;
254 struct thread *newtd, *oldtd;
255
256 if (!proc0.p_stats)
257 panic("kthread_add called too soon");
258
259 /* If no process supplied, put it on proc0 */
260 if (p == NULL)
261 p = &proc0;
262
263 /* Initialize our new td */
264 newtd = thread_alloc(pages);
265 if (newtd == NULL)
266 return (ENOMEM);
267
268 PROC_LOCK(p);
269 oldtd = FIRST_THREAD_IN_PROC(p);
270
271 bzero(&newtd->td_startzero,
272 __rangeof(struct thread, td_startzero, td_endzero));
273 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
274 __rangeof(struct thread, td_startcopy, td_endcopy));
275
276 /* set up arg0 for 'ps', et al */
277 va_start(ap, fmt);
278 vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap);
279 va_end(ap);
280
281 newtd->td_proc = p; /* needed for cpu_set_upcall */
282
283 /* XXX optimise this probably? */
284 /* On x86 (and probably the others too) it is way too full of junk */
285 /* Needs a better name */
286 cpu_set_upcall(newtd, oldtd);
287 /* put the designated function(arg) as the resume context */
288 cpu_set_fork_handler(newtd, func, arg);
289
290 newtd->td_pflags |= TDP_KTHREAD;
291 newtd->td_ucred = crhold(p->p_ucred);
292
293 /* this code almost the same as create_thread() in kern_thr.c */
294 p->p_flag |= P_HADTHREADS;
295 thread_link(newtd, p);
296 thread_lock(oldtd);
297 /* let the scheduler know about these things. */
298 sched_fork_thread(oldtd, newtd);
299 TD_SET_CAN_RUN(newtd);
300 thread_unlock(oldtd);
301 PROC_UNLOCK(p);
302
303 tidhash_add(newtd);
304
305 /* Avoid inheriting affinity from a random parent. */
306 cpuset_setthread(newtd->td_tid, cpuset_root);
307
308 /* Delay putting it on the run queue until now. */
309 if (!(flags & RFSTOPPED)) {
310 thread_lock(newtd);
311 sched_add(newtd, SRQ_BORING);
312 thread_unlock(newtd);
313 }
314 if (newtdp)
315 *newtdp = newtd;
316 return 0;
317 }
318
319 void
320 kthread_exit(void)
321 {
322 struct proc *p;
323
324 p = curthread->td_proc;
325
326 /* A module may be waiting for us to exit. */
327 wakeup(curthread);
328
329 /*
330 * The last exiting thread in a kernel process must tear down
331 * the whole process.
332 */
333 rw_wlock(&tidhash_lock);
334 PROC_LOCK(p);
335 if (p->p_numthreads == 1) {
336 PROC_UNLOCK(p);
337 rw_wunlock(&tidhash_lock);
338 kproc_exit(0);
339 }
340 LIST_REMOVE(curthread, td_hash);
341 rw_wunlock(&tidhash_lock);
342 PROC_SLOCK(p);
343 thread_exit();
344 }
345
346 /*
347 * Advise a kernel process to suspend (or resume) in its main loop.
348 * Participation is voluntary.
349 */
350 int
351 kthread_suspend(struct thread *td, int timo)
352 {
353 struct proc *p;
354
355 p = td->td_proc;
356
357 /*
358 * td_pflags should not be read by any thread other than
359 * curthread, but as long as this flag is invariant during the
360 * thread's lifetime, it is OK to check its state.
361 */
362 if ((td->td_pflags & TDP_KTHREAD) == 0)
363 return (EINVAL);
364
365 /*
366 * The caller of the primitive should have already checked that the
367 * thread is up and running, thus not being blocked by other
368 * conditions.
369 */
370 PROC_LOCK(p);
371 thread_lock(td);
372 td->td_flags |= TDF_KTH_SUSP;
373 thread_unlock(td);
374 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt",
375 timo));
376 }
377
378 /*
379 * Resume a thread previously put asleep with kthread_suspend().
380 */
381 int
382 kthread_resume(struct thread *td)
383 {
384 struct proc *p;
385
386 p = td->td_proc;
387
388 /*
389 * td_pflags should not be read by any thread other than
390 * curthread, but as long as this flag is invariant during the
391 * thread's lifetime, it is OK to check its state.
392 */
393 if ((td->td_pflags & TDP_KTHREAD) == 0)
394 return (EINVAL);
395
396 PROC_LOCK(p);
397 thread_lock(td);
398 td->td_flags &= ~TDF_KTH_SUSP;
399 thread_unlock(td);
400 wakeup(&td->td_flags);
401 PROC_UNLOCK(p);
402 return (0);
403 }
404
405 /*
406 * Used by the thread to poll as to whether it should yield/sleep
407 * and notify the caller that is has happened.
408 */
409 void
410 kthread_suspend_check()
411 {
412 struct proc *p;
413 struct thread *td;
414
415 td = curthread;
416 p = td->td_proc;
417
418 if ((td->td_pflags & TDP_KTHREAD) == 0)
419 panic("%s: curthread is not a valid kthread", __func__);
420
421 /*
422 * As long as the double-lock protection is used when accessing the
423 * TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex
424 * is fine.
425 */
426 PROC_LOCK(p);
427 while (td->td_flags & TDF_KTH_SUSP) {
428 wakeup(&td->td_flags);
429 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0);
430 }
431 PROC_UNLOCK(p);
432 }
433
434 int
435 kproc_kthread_add(void (*func)(void *), void *arg,
436 struct proc **procptr, struct thread **tdptr,
437 int flags, int pages, const char *procname, const char *fmt, ...)
438 {
439 int error;
440 va_list ap;
441 char buf[100];
442 struct thread *td;
443
444 if (*procptr == 0) {
445 error = kproc_create(func, arg,
446 procptr, flags, pages, "%s", procname);
447 if (error)
448 return (error);
449 td = FIRST_THREAD_IN_PROC(*procptr);
450 if (tdptr)
451 *tdptr = td;
452 va_start(ap, fmt);
453 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
454 va_end(ap);
455 #ifdef KTR
456 sched_clear_tdname(td);
457 #endif
458 return (0);
459 }
460 va_start(ap, fmt);
461 vsnprintf(buf, sizeof(buf), fmt, ap);
462 va_end(ap);
463 error = kthread_add(func, arg, *procptr,
464 tdptr, flags, pages, "%s", buf);
465 return (error);
466 }
Cache object: 6e07c5e78e558589737f600b281a2696
|