1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1999 Peter Wemm <peter@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/param.h>
30 #include <sys/systm.h>
31 #include <sys/cpuset.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/rwlock.h>
38 #include <sys/signalvar.h>
39 #include <sys/sysent.h>
40 #include <sys/sx.h>
41 #include <sys/umtxvar.h>
42 #include <sys/unistd.h>
43 #include <sys/wait.h>
44 #include <sys/sched.h>
45 #include <sys/tslog.h>
46 #include <vm/vm.h>
47 #include <vm/vm_extern.h>
48
49 #include <machine/stdarg.h>
50
51 /*
52 * Start a kernel process. This is called after a fork() call in
53 * mi_startup() in the file kern/init_main.c.
54 *
55 * This function is used to start "internal" daemons and intended
56 * to be called from SYSINIT().
57 */
58 void
kproc_start(const void * udata)59 kproc_start(const void *udata)
60 {
61 const struct kproc_desc *kp = udata;
62 int error;
63
64 error = kproc_create((void (*)(void *))kp->func, NULL,
65 kp->global_procpp, 0, 0, "%s", kp->arg0);
66 if (error)
67 panic("kproc_start: %s: error %d", kp->arg0, error);
68 }
69
70 /*
71 * Create a kernel process/thread/whatever. It shares its address space
72 * with proc0 - ie: kernel only.
73 *
74 * func is the function to start.
75 * arg is the parameter to pass to function on first startup.
76 * newpp is the return value pointing to the thread's struct proc.
77 * flags are flags to fork1 (in unistd.h)
78 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
79 */
80 static int
kproc_create1(void (* func)(void *),void * arg,struct proc ** newpp,int flags,int pages,const char * tdname)81 kproc_create1(void (*func)(void *), void *arg,
82 struct proc **newpp, int flags, int pages, const char *tdname)
83 {
84 struct fork_req fr;
85 int error;
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_flags2 = FR2_KPROC;
95 fr.fr_pages = pages;
96 fr.fr_procp = &p2;
97 error = fork1(&thread0, &fr);
98 if (error != 0)
99 return (error);
100
101 /* save a global descriptor, if desired */
102 if (newpp != NULL)
103 *newpp = p2;
104
105 /* set up arg0 for 'ps', et al */
106 strcpy(p2->p_comm, tdname);
107 td = FIRST_THREAD_IN_PROC(p2);
108 strcpy(td->td_name, tdname);
109 #ifdef KTR
110 sched_clear_tdname(td);
111 #endif
112 TSTHREAD(td, td->td_name);
113 #ifdef HWPMC_HOOKS
114 if (PMC_SYSTEM_SAMPLING_ACTIVE()) {
115 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_PROC_CREATE_LOG, p2);
116 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL);
117 }
118 #endif
119
120 /* call the processes' main()... */
121 cpu_fork_kthread_handler(td, func, arg);
122
123 /* Avoid inheriting affinity from a random parent. */
124 cpuset_kernthread(td);
125 thread_lock(td);
126 TD_SET_CAN_RUN(td);
127 sched_prio(td, PVM);
128 sched_user_prio(td, PUSER);
129
130 /* Delay putting it on the run queue until now. */
131 if ((flags & RFSTOPPED) == 0)
132 sched_add(td, SRQ_BORING);
133 else
134 thread_unlock(td);
135
136 return (0);
137 }
138
139 int
kproc_create(void (* func)(void *),void * arg,struct proc ** newpp,int flags,int pages,const char * fmt,...)140 kproc_create(void (*func)(void *), void *arg,
141 struct proc **newpp, int flags, int pages, const char *fmt, ...)
142 {
143 va_list ap;
144 int error;
145 char tdname[MAXCOMLEN + 1];
146
147 va_start(ap, fmt);
148 vsnprintf(tdname, sizeof(tdname), fmt, ap);
149 va_end(ap);
150 DROP_GIANT();
151 error = kproc_create1(func, arg, newpp, flags, pages, tdname);
152 PICKUP_GIANT();
153 return (error);
154 }
155
156 void
kproc_exit(int ecode)157 kproc_exit(int ecode)
158 {
159 struct thread *td;
160 struct proc *p;
161
162 td = curthread;
163 p = td->td_proc;
164
165 /*
166 * Reparent curthread from proc0 to init so that the zombie
167 * is harvested.
168 */
169 sx_xlock(&proctree_lock);
170 PROC_LOCK(p);
171 proc_reparent(p, initproc, true);
172 PROC_UNLOCK(p);
173 sx_xunlock(&proctree_lock);
174
175 /*
176 * Wakeup anyone waiting for us to exit.
177 */
178 wakeup(p);
179
180 /* Buh-bye! */
181 exit1(td, ecode, 0);
182 }
183
184 /*
185 * Advise a kernel process to suspend (or resume) in its main loop.
186 * Participation is voluntary.
187 */
188 int
kproc_suspend(struct proc * p,int timo)189 kproc_suspend(struct proc *p, int timo)
190 {
191 /*
192 * Make sure this is indeed a system process and we can safely
193 * use the p_siglist field.
194 */
195 PROC_LOCK(p);
196 if ((p->p_flag & P_KPROC) == 0) {
197 PROC_UNLOCK(p);
198 return (EINVAL);
199 }
200 SIGADDSET(p->p_siglist, SIGSTOP);
201 wakeup(p);
202 return (msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP,
203 "suspkp", timo));
204 }
205
206 int
kproc_resume(struct proc * p)207 kproc_resume(struct proc *p)
208 {
209 /*
210 * Make sure this is indeed a system process and we can safely
211 * use the p_siglist field.
212 */
213 PROC_LOCK(p);
214 if ((p->p_flag & P_KPROC) == 0) {
215 PROC_UNLOCK(p);
216 return (EINVAL);
217 }
218 SIGDELSET(p->p_siglist, SIGSTOP);
219 PROC_UNLOCK(p);
220 wakeup(&p->p_siglist);
221 return (0);
222 }
223
224 void
kproc_suspend_check(struct proc * p)225 kproc_suspend_check(struct proc *p)
226 {
227 PROC_LOCK(p);
228 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
229 wakeup(&p->p_siglist);
230 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
231 }
232 PROC_UNLOCK(p);
233 }
234
235 /*
236 * Start a kernel thread.
237 *
238 * This function is used to start "internal" daemons and intended
239 * to be called from SYSINIT().
240 */
241
242 void
kthread_start(const void * udata)243 kthread_start(const void *udata)
244 {
245 const struct kthread_desc *kp = udata;
246 int error;
247
248 error = kthread_add((void (*)(void *))kp->func, NULL,
249 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
250 if (error)
251 panic("kthread_start: %s: error %d", kp->arg0, error);
252 }
253
254 /*
255 * Create a kernel thread. It shares its address space
256 * with proc0 - ie: kernel only.
257 *
258 * func is the function to start.
259 * arg is the parameter to pass to function on first startup.
260 * newtdp is the return value pointing to the thread's struct thread.
261 * ** XXX fix this --> flags are flags to fork1 (in unistd.h)
262 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
263 */
264 static int
kthread_add1(void (* func)(void *),void * arg,struct proc * p,struct thread ** newtdp,int flags,int pages,const char * tdname)265 kthread_add1(void (*func)(void *), void *arg, struct proc *p,
266 struct thread **newtdp, int flags, int pages, const char *tdname)
267 {
268 struct thread *newtd, *oldtd;
269
270 if (!proc0.p_stats)
271 panic("kthread_add called too soon");
272
273 /* If no process supplied, put it on proc0 */
274 if (p == NULL)
275 p = &proc0;
276
277 /* Initialize our new td */
278 newtd = thread_alloc(pages);
279 if (newtd == NULL)
280 return (ENOMEM);
281
282 PROC_LOCK(p);
283 if (p->p_state == PRS_ZOMBIE || (p->p_flag2 & P2_WEXIT) != 0) {
284 PROC_UNLOCK(p);
285 return (ESRCH);
286 }
287 oldtd = FIRST_THREAD_IN_PROC(p);
288
289 /*
290 * Set the new thread pointer before the thread starts running: *newtdp
291 * could be a pointer that is referenced by "func".
292 */
293 if (newtdp != NULL)
294 *newtdp = newtd;
295
296 bzero(&newtd->td_startzero,
297 __rangeof(struct thread, td_startzero, td_endzero));
298 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
299 __rangeof(struct thread, td_startcopy, td_endcopy));
300
301 /* set up arg0 for 'ps', et al */
302 strcpy(newtd->td_name, tdname);
303
304 TSTHREAD(newtd, newtd->td_name);
305
306 newtd->td_proc = p; /* needed for cpu_copy_thread */
307 newtd->td_pflags |= TDP_KTHREAD;
308
309 /* might be further optimized for kthread */
310 cpu_copy_thread(newtd, oldtd);
311
312 /* put the designated function(arg) as the resume context */
313 cpu_fork_kthread_handler(newtd, func, arg);
314
315 thread_cow_get_proc(newtd, p);
316
317 /* This code is similar to thread_create() in kern_thr.c. */
318 p->p_flag |= P_HADTHREADS;
319 thread_link(newtd, p);
320 thread_lock(oldtd);
321 /* let the scheduler know about these things. */
322 sched_fork_thread(oldtd, newtd);
323 TD_SET_CAN_RUN(newtd);
324 thread_unlock(oldtd);
325 PROC_UNLOCK(p);
326
327 tidhash_add(newtd);
328
329 /* Avoid inheriting affinity from a random parent. */
330 cpuset_kernthread(newtd);
331 #ifdef HWPMC_HOOKS
332 if (PMC_SYSTEM_SAMPLING_ACTIVE())
333 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL);
334 #endif
335 /* Delay putting it on the run queue until now. */
336 if ((flags & RFSTOPPED) == 0) {
337 thread_lock(newtd);
338 sched_add(newtd, SRQ_BORING);
339 }
340 return (0);
341 }
342
343 int
kthread_add(void (* func)(void *),void * arg,struct proc * p,struct thread ** newtdp,int flags,int pages,const char * fmt,...)344 kthread_add(void (*func)(void *), void *arg, struct proc *p,
345 struct thread **newtdp, int flags, int pages, const char *fmt, ...)
346 {
347 va_list ap;
348 int error;
349 char tdname[MAXCOMLEN + 1];
350
351 va_start(ap, fmt);
352 vsnprintf(tdname, sizeof(tdname), fmt, ap);
353 va_end(ap);
354 DROP_GIANT();
355 error = kthread_add1(func, arg, p, newtdp, flags, pages, tdname);
356 PICKUP_GIANT();
357 return (error);
358 }
359
360 void
kthread_exit(void)361 kthread_exit(void)
362 {
363 struct proc *p;
364 struct thread *td;
365
366 td = curthread;
367 p = td->td_proc;
368
369 #ifdef HWPMC_HOOKS
370 if (PMC_SYSTEM_SAMPLING_ACTIVE())
371 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_EXIT_LOG, NULL);
372 #endif
373 /* A module may be waiting for us to exit. */
374 wakeup(td);
375
376 /*
377 * The last exiting thread in a kernel process must tear down
378 * the whole process.
379 */
380 PROC_LOCK(p);
381 if (p->p_numthreads == 1) {
382 PROC_UNLOCK(p);
383 kproc_exit(0);
384 }
385
386 if (p->p_sysent->sv_ontdexit != NULL)
387 p->p_sysent->sv_ontdexit(td);
388
389 tidhash_remove(td);
390 umtx_thread_exit(td);
391 tdsigcleanup(td);
392 PROC_SLOCK(p);
393 thread_exit();
394 }
395
396 /*
397 * Advise a kernel process to suspend (or resume) in its main loop.
398 * Participation is voluntary.
399 */
400 int
kthread_suspend(struct thread * td,int timo)401 kthread_suspend(struct thread *td, int timo)
402 {
403 struct proc *p;
404
405 p = td->td_proc;
406
407 /*
408 * td_pflags should not be read by any thread other than
409 * curthread, but as long as this flag is invariant during the
410 * thread's lifetime, it is OK to check its state.
411 */
412 if ((td->td_pflags & TDP_KTHREAD) == 0)
413 return (EINVAL);
414
415 /*
416 * The caller of the primitive should have already checked that the
417 * thread is up and running, thus not being blocked by other
418 * conditions.
419 */
420 PROC_LOCK(p);
421 thread_lock(td);
422 td->td_flags |= TDF_KTH_SUSP;
423 thread_unlock(td);
424 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt",
425 timo));
426 }
427
428 /*
429 * Resume a thread previously put asleep with kthread_suspend().
430 */
431 int
kthread_resume(struct thread * td)432 kthread_resume(struct thread *td)
433 {
434 struct proc *p;
435
436 p = td->td_proc;
437
438 /*
439 * td_pflags should not be read by any thread other than
440 * curthread, but as long as this flag is invariant during the
441 * thread's lifetime, it is OK to check its state.
442 */
443 if ((td->td_pflags & TDP_KTHREAD) == 0)
444 return (EINVAL);
445
446 PROC_LOCK(p);
447 thread_lock(td);
448 td->td_flags &= ~TDF_KTH_SUSP;
449 thread_unlock(td);
450 wakeup(&td->td_flags);
451 PROC_UNLOCK(p);
452 return (0);
453 }
454
455 /*
456 * Used by the thread to poll as to whether it should yield/sleep
457 * and notify the caller that is has happened.
458 */
459 void
kthread_suspend_check(void)460 kthread_suspend_check(void)
461 {
462 struct proc *p;
463 struct thread *td;
464
465 td = curthread;
466 p = td->td_proc;
467
468 if ((td->td_pflags & TDP_KTHREAD) == 0)
469 panic("%s: curthread is not a valid kthread", __func__);
470
471 /*
472 * Setting the TDF_KTH_SUSP flag is protected by process lock.
473 *
474 * Do an unlocked read first to avoid serializing with all other threads
475 * in the common case of not suspending.
476 */
477 if ((td->td_flags & TDF_KTH_SUSP) == 0)
478 return;
479 PROC_LOCK(p);
480 while ((td->td_flags & TDF_KTH_SUSP) != 0) {
481 wakeup(&td->td_flags);
482 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0);
483 }
484 PROC_UNLOCK(p);
485 }
486
487 int
kproc_kthread_add(void (* func)(void *),void * arg,struct proc ** procptr,struct thread ** tdptr,int flags,int pages,const char * procname,const char * fmt,...)488 kproc_kthread_add(void (*func)(void *), void *arg,
489 struct proc **procptr, struct thread **tdptr,
490 int flags, int pages, const char *procname, const char *fmt, ...)
491 {
492 int error;
493 va_list ap;
494 char buf[100];
495 struct thread *td;
496
497 if (*procptr == NULL) {
498 /*
499 * Use RFSTOPPED to ensure that *tdptr is initialized before the
500 * thread starts running.
501 */
502 error = kproc_create(func, arg,
503 procptr, flags | RFSTOPPED, pages, "%s", procname);
504 if (error)
505 return (error);
506 td = FIRST_THREAD_IN_PROC(*procptr);
507 if (tdptr)
508 *tdptr = td;
509 if ((flags & RFSTOPPED) == 0) {
510 thread_lock(td);
511 sched_add(td, SRQ_BORING);
512 }
513 va_start(ap, fmt);
514 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
515 va_end(ap);
516 #ifdef KTR
517 sched_clear_tdname(td);
518 #endif
519 return (0);
520 }
521 va_start(ap, fmt);
522 vsnprintf(buf, sizeof(buf), fmt, ap);
523 va_end(ap);
524 error = kthread_add(func, arg, *procptr,
525 tdptr, flags, pages, "%s", buf);
526 return (error);
527 }
528