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/11.1/sys/kern/kern_kthread.c 304883 2016-08-27 09:23:20Z kib $");
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/umtx.h>
42 #include <sys/unistd.h>
43 #include <sys/wait.h>
44 #include <sys/sched.h>
45 #include <vm/vm.h>
46 #include <vm/vm_extern.h>
47
48 #include <machine/stdarg.h>
49
50 /*
51 * Start a kernel process. This is called after a fork() call in
52 * mi_startup() in the file kern/init_main.c.
53 *
54 * This function is used to start "internal" daemons and intended
55 * to be called from SYSINIT().
56 */
57 void
58 kproc_start(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 struct fork_req fr;
84 int error;
85 va_list ap;
86 struct thread *td;
87 struct proc *p2;
88
89 if (!proc0.p_stats)
90 panic("kproc_create called too soon");
91
92 bzero(&fr, sizeof(fr));
93 fr.fr_flags = RFMEM | RFFDG | RFPROC | RFSTOPPED | flags;
94 fr.fr_pages = pages;
95 fr.fr_procp = &p2;
96 error = fork1(&thread0, &fr);
97 if (error)
98 return error;
99
100 /* save a global descriptor, if desired */
101 if (newpp != NULL)
102 *newpp = p2;
103
104 /* this is a non-swapped system process */
105 PROC_LOCK(p2);
106 td = FIRST_THREAD_IN_PROC(p2);
107 p2->p_flag |= P_SYSTEM | P_KPROC;
108 td->td_pflags |= TDP_KTHREAD;
109 mtx_lock(&p2->p_sigacts->ps_mtx);
110 p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
111 mtx_unlock(&p2->p_sigacts->ps_mtx);
112 PROC_UNLOCK(p2);
113
114 /* set up arg0 for 'ps', et al */
115 va_start(ap, fmt);
116 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
117 va_end(ap);
118 /* set up arg0 for 'ps', et al */
119 va_start(ap, fmt);
120 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
121 va_end(ap);
122 #ifdef KTR
123 sched_clear_tdname(td);
124 #endif
125
126 /* call the processes' main()... */
127 cpu_fork_kthread_handler(td, func, arg);
128
129 /* Avoid inheriting affinity from a random parent. */
130 cpuset_setthread(td->td_tid, cpuset_root);
131 thread_lock(td);
132 TD_SET_CAN_RUN(td);
133 sched_prio(td, PVM);
134 sched_user_prio(td, PUSER);
135
136 /* Delay putting it on the run queue until now. */
137 if (!(flags & RFSTOPPED))
138 sched_add(td, SRQ_BORING);
139 thread_unlock(td);
140
141 return 0;
142 }
143
144 void
145 kproc_exit(int ecode)
146 {
147 struct thread *td;
148 struct proc *p;
149
150 td = curthread;
151 p = td->td_proc;
152
153 /*
154 * Reparent curthread from proc0 to init so that the zombie
155 * is harvested.
156 */
157 sx_xlock(&proctree_lock);
158 PROC_LOCK(p);
159 proc_reparent(p, initproc);
160 PROC_UNLOCK(p);
161 sx_xunlock(&proctree_lock);
162
163 /*
164 * Wakeup anyone waiting for us to exit.
165 */
166 wakeup(p);
167
168 /* Buh-bye! */
169 exit1(td, ecode, 0);
170 }
171
172 /*
173 * Advise a kernel process to suspend (or resume) in its main loop.
174 * Participation is voluntary.
175 */
176 int
177 kproc_suspend(struct proc *p, int timo)
178 {
179 /*
180 * Make sure this is indeed a system process and we can safely
181 * use the p_siglist field.
182 */
183 PROC_LOCK(p);
184 if ((p->p_flag & P_KPROC) == 0) {
185 PROC_UNLOCK(p);
186 return (EINVAL);
187 }
188 SIGADDSET(p->p_siglist, SIGSTOP);
189 wakeup(p);
190 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo);
191 }
192
193 int
194 kproc_resume(struct proc *p)
195 {
196 /*
197 * Make sure this is indeed a system process and we can safely
198 * use the p_siglist field.
199 */
200 PROC_LOCK(p);
201 if ((p->p_flag & P_KPROC) == 0) {
202 PROC_UNLOCK(p);
203 return (EINVAL);
204 }
205 SIGDELSET(p->p_siglist, SIGSTOP);
206 PROC_UNLOCK(p);
207 wakeup(&p->p_siglist);
208 return (0);
209 }
210
211 void
212 kproc_suspend_check(struct proc *p)
213 {
214 PROC_LOCK(p);
215 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
216 wakeup(&p->p_siglist);
217 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
218 }
219 PROC_UNLOCK(p);
220 }
221
222
223 /*
224 * Start a kernel thread.
225 *
226 * This function is used to start "internal" daemons and intended
227 * to be called from SYSINIT().
228 */
229
230 void
231 kthread_start(const void *udata)
232 {
233 const struct kthread_desc *kp = udata;
234 int error;
235
236 error = kthread_add((void (*)(void *))kp->func, NULL,
237 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
238 if (error)
239 panic("kthread_start: %s: error %d", kp->arg0, error);
240 }
241
242 /*
243 * Create a kernel thread. It shares its address space
244 * with proc0 - ie: kernel only.
245 *
246 * func is the function to start.
247 * arg is the parameter to pass to function on first startup.
248 * newtdp is the return value pointing to the thread's struct thread.
249 * ** XXX fix this --> flags are flags to fork1 (in unistd.h)
250 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
251 */
252 int
253 kthread_add(void (*func)(void *), void *arg, struct proc *p,
254 struct thread **newtdp, int flags, int pages, const char *fmt, ...)
255 {
256 va_list ap;
257 struct thread *newtd, *oldtd;
258
259 if (!proc0.p_stats)
260 panic("kthread_add called too soon");
261
262 /* If no process supplied, put it on proc0 */
263 if (p == NULL)
264 p = &proc0;
265
266 /* Initialize our new td */
267 newtd = thread_alloc(pages);
268 if (newtd == NULL)
269 return (ENOMEM);
270
271 PROC_LOCK(p);
272 oldtd = FIRST_THREAD_IN_PROC(p);
273
274 bzero(&newtd->td_startzero,
275 __rangeof(struct thread, td_startzero, td_endzero));
276 newtd->td_sleeptimo = 0;
277 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
278 __rangeof(struct thread, td_startcopy, td_endcopy));
279
280 /* set up arg0 for 'ps', et al */
281 va_start(ap, fmt);
282 vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap);
283 va_end(ap);
284
285 newtd->td_proc = p; /* needed for cpu_copy_thread */
286 /* might be further optimized for kthread */
287 cpu_copy_thread(newtd, oldtd);
288 /* put the designated function(arg) as the resume context */
289 cpu_fork_kthread_handler(newtd, func, arg);
290
291 newtd->td_pflags |= TDP_KTHREAD;
292 thread_cow_get_proc(newtd, p);
293
294 /* this code almost the same as create_thread() in kern_thr.c */
295 p->p_flag |= P_HADTHREADS;
296 thread_link(newtd, p);
297 thread_lock(oldtd);
298 /* let the scheduler know about these things. */
299 sched_fork_thread(oldtd, newtd);
300 TD_SET_CAN_RUN(newtd);
301 thread_unlock(oldtd);
302 PROC_UNLOCK(p);
303
304 tidhash_add(newtd);
305
306 /* Avoid inheriting affinity from a random parent. */
307 cpuset_setthread(newtd->td_tid, cpuset_root);
308
309 /* Delay putting it on the run queue until now. */
310 if (!(flags & RFSTOPPED)) {
311 thread_lock(newtd);
312 sched_add(newtd, SRQ_BORING);
313 thread_unlock(newtd);
314 }
315 if (newtdp)
316 *newtdp = newtd;
317 return 0;
318 }
319
320 void
321 kthread_exit(void)
322 {
323 struct proc *p;
324 struct thread *td;
325
326 td = curthread;
327 p = td->td_proc;
328
329 /* A module may be waiting for us to exit. */
330 wakeup(td);
331
332 /*
333 * The last exiting thread in a kernel process must tear down
334 * the whole process.
335 */
336 rw_wlock(&tidhash_lock);
337 PROC_LOCK(p);
338 if (p->p_numthreads == 1) {
339 PROC_UNLOCK(p);
340 rw_wunlock(&tidhash_lock);
341 kproc_exit(0);
342 }
343 LIST_REMOVE(td, td_hash);
344 rw_wunlock(&tidhash_lock);
345 umtx_thread_exit(td);
346 tdsigcleanup(td);
347 PROC_SLOCK(p);
348 thread_exit();
349 }
350
351 /*
352 * Advise a kernel process to suspend (or resume) in its main loop.
353 * Participation is voluntary.
354 */
355 int
356 kthread_suspend(struct thread *td, int timo)
357 {
358 struct proc *p;
359
360 p = td->td_proc;
361
362 /*
363 * td_pflags should not be read by any thread other than
364 * curthread, but as long as this flag is invariant during the
365 * thread's lifetime, it is OK to check its state.
366 */
367 if ((td->td_pflags & TDP_KTHREAD) == 0)
368 return (EINVAL);
369
370 /*
371 * The caller of the primitive should have already checked that the
372 * thread is up and running, thus not being blocked by other
373 * conditions.
374 */
375 PROC_LOCK(p);
376 thread_lock(td);
377 td->td_flags |= TDF_KTH_SUSP;
378 thread_unlock(td);
379 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt",
380 timo));
381 }
382
383 /*
384 * Resume a thread previously put asleep with kthread_suspend().
385 */
386 int
387 kthread_resume(struct thread *td)
388 {
389 struct proc *p;
390
391 p = td->td_proc;
392
393 /*
394 * td_pflags should not be read by any thread other than
395 * curthread, but as long as this flag is invariant during the
396 * thread's lifetime, it is OK to check its state.
397 */
398 if ((td->td_pflags & TDP_KTHREAD) == 0)
399 return (EINVAL);
400
401 PROC_LOCK(p);
402 thread_lock(td);
403 td->td_flags &= ~TDF_KTH_SUSP;
404 thread_unlock(td);
405 wakeup(&td->td_flags);
406 PROC_UNLOCK(p);
407 return (0);
408 }
409
410 /*
411 * Used by the thread to poll as to whether it should yield/sleep
412 * and notify the caller that is has happened.
413 */
414 void
415 kthread_suspend_check(void)
416 {
417 struct proc *p;
418 struct thread *td;
419
420 td = curthread;
421 p = td->td_proc;
422
423 if ((td->td_pflags & TDP_KTHREAD) == 0)
424 panic("%s: curthread is not a valid kthread", __func__);
425
426 /*
427 * As long as the double-lock protection is used when accessing the
428 * TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex
429 * is fine.
430 */
431 PROC_LOCK(p);
432 while (td->td_flags & TDF_KTH_SUSP) {
433 wakeup(&td->td_flags);
434 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0);
435 }
436 PROC_UNLOCK(p);
437 }
438
439 int
440 kproc_kthread_add(void (*func)(void *), void *arg,
441 struct proc **procptr, struct thread **tdptr,
442 int flags, int pages, const char *procname, const char *fmt, ...)
443 {
444 int error;
445 va_list ap;
446 char buf[100];
447 struct thread *td;
448
449 if (*procptr == NULL) {
450 error = kproc_create(func, arg,
451 procptr, flags, pages, "%s", procname);
452 if (error)
453 return (error);
454 td = FIRST_THREAD_IN_PROC(*procptr);
455 if (tdptr)
456 *tdptr = td;
457 va_start(ap, fmt);
458 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
459 va_end(ap);
460 #ifdef KTR
461 sched_clear_tdname(td);
462 #endif
463 return (0);
464 }
465 va_start(ap, fmt);
466 vsnprintf(buf, sizeof(buf), fmt, ap);
467 va_end(ap);
468 error = kthread_add(func, arg, *procptr,
469 tdptr, flags, pages, "%s", buf);
470 return (error);
471 }
Cache object: a4352d48d846588ad7f9fea153ac4f34
|