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/stdarg.h>
46 #include <sys/tslog.h>
47 #include <vm/vm.h>
48 #include <vm/vm_extern.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
kproc_start(const void * udata)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 static int
kproc_create1(void (* func)(void *),void * arg,struct proc ** newpp,int flags,int pages,const char * tdname)80 kproc_create1(void (*func)(void *), void *arg,
81 struct proc **newpp, int flags, int pages, const char *tdname)
82 {
83 struct fork_req fr;
84 int error;
85 struct thread *td;
86 struct proc *p2;
87
88 if (!proc0.p_stats)
89 panic("kproc_create called too soon");
90
91 bzero(&fr, sizeof(fr));
92 fr.fr_flags = RFMEM | RFFDG | RFPROC | RFSTOPPED | flags;
93 fr.fr_flags2 = FR2_KPROC;
94 fr.fr_pages = pages;
95 fr.fr_procp = &p2;
96 error = fork1(&thread0, &fr);
97 if (error != 0)
98 return (error);
99
100 /* save a global descriptor, if desired */
101 if (newpp != NULL)
102 *newpp = p2;
103
104 /* set up arg0 for 'ps', et al */
105 strcpy(p2->p_comm, tdname);
106 td = FIRST_THREAD_IN_PROC(p2);
107 strcpy(td->td_name, tdname);
108 #ifdef KTR
109 sched_clear_tdname(td);
110 #endif
111 TSTHREAD(td, td->td_name);
112 #ifdef HWPMC_HOOKS
113 if (PMC_SYSTEM_SAMPLING_ACTIVE()) {
114 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_PROC_CREATE_LOG, p2);
115 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL);
116 }
117 #endif
118
119 /* call the processes' main()... */
120 cpu_fork_kthread_handler(td, func, arg);
121
122 /* Avoid inheriting affinity from a random parent. */
123 cpuset_kernthread(td);
124 thread_lock(td);
125 TD_SET_CAN_RUN(td);
126 sched_prio(td, PVM);
127 sched_user_prio(td, PUSER);
128
129 /* Delay putting it on the run queue until now. */
130 if ((flags & RFSTOPPED) == 0)
131 sched_add(td, SRQ_BORING);
132 else
133 thread_unlock(td);
134
135 return (0);
136 }
137
138 int
kproc_create(void (* func)(void *),void * arg,struct proc ** newpp,int flags,int pages,const char * fmt,...)139 kproc_create(void (*func)(void *), void *arg,
140 struct proc **newpp, int flags, int pages, const char *fmt, ...)
141 {
142 va_list ap;
143 int error;
144 char tdname[MAXCOMLEN + 1];
145
146 va_start(ap, fmt);
147 vsnprintf(tdname, sizeof(tdname), fmt, ap);
148 va_end(ap);
149 DROP_GIANT();
150 error = kproc_create1(func, arg, newpp, flags, pages, tdname);
151 PICKUP_GIANT();
152 return (error);
153 }
154
155 void
kproc_exit(int ecode)156 kproc_exit(int ecode)
157 {
158 struct thread *td;
159 struct proc *p;
160
161 td = curthread;
162 p = td->td_proc;
163
164 /*
165 * Reparent curthread from proc0 to init so that the zombie
166 * is harvested.
167 */
168 sx_xlock(&proctree_lock);
169 PROC_LOCK(p);
170 proc_reparent(p, initproc, true);
171 PROC_UNLOCK(p);
172 sx_xunlock(&proctree_lock);
173
174 /*
175 * Wakeup anyone waiting for us to exit.
176 */
177 wakeup(p);
178
179 /* Buh-bye! */
180 exit1(td, ecode, 0);
181 }
182
183 /*
184 * Advise a kernel process to suspend (or resume) in its main loop.
185 * Participation is voluntary.
186 */
187 int
kproc_suspend(struct proc * p,int timo)188 kproc_suspend(struct proc *p, int timo)
189 {
190 /*
191 * Make sure this is indeed a system process and we can safely
192 * use the p_siglist field.
193 */
194 PROC_LOCK(p);
195 if ((p->p_flag & P_KPROC) == 0) {
196 PROC_UNLOCK(p);
197 return (EINVAL);
198 }
199 SIGADDSET(p->p_siglist, SIGSTOP);
200 wakeup(p);
201 return (msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP,
202 "suspkp", timo));
203 }
204
205 int
kproc_resume(struct proc * p)206 kproc_resume(struct proc *p)
207 {
208 /*
209 * Make sure this is indeed a system process and we can safely
210 * use the p_siglist field.
211 */
212 PROC_LOCK(p);
213 if ((p->p_flag & P_KPROC) == 0) {
214 PROC_UNLOCK(p);
215 return (EINVAL);
216 }
217 SIGDELSET(p->p_siglist, SIGSTOP);
218 PROC_UNLOCK(p);
219 wakeup(&p->p_siglist);
220 return (0);
221 }
222
223 void
kproc_suspend_check(struct proc * p)224 kproc_suspend_check(struct proc *p)
225 {
226 PROC_LOCK(p);
227 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
228 wakeup(&p->p_siglist);
229 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
230 }
231 PROC_UNLOCK(p);
232 }
233
234 /*
235 * Start a kernel thread.
236 *
237 * This function is used to start "internal" daemons and intended
238 * to be called from SYSINIT().
239 */
240
241 void
kthread_start(const void * udata)242 kthread_start(const void *udata)
243 {
244 const struct kthread_desc *kp = udata;
245 int error;
246
247 error = kthread_add((void (*)(void *))kp->func, NULL,
248 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
249 if (error)
250 panic("kthread_start: %s: error %d", kp->arg0, error);
251 }
252
253 /*
254 * Create a kernel thread. It shares its address space
255 * with proc0 - ie: kernel only.
256 *
257 * func is the function to start.
258 * arg is the parameter to pass to function on first startup.
259 * newtdp is the return value pointing to the thread's struct thread.
260 * ** XXX fix this --> flags are flags to fork1 (in unistd.h)
261 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
262 */
263 static int
kthread_add1(void (* func)(void *),void * arg,struct proc * p,struct thread ** newtdp,int flags,int pages,const char * tdname)264 kthread_add1(void (*func)(void *), void *arg, struct proc *p,
265 struct thread **newtdp, int flags, int pages, const char *tdname)
266 {
267 struct thread *newtd, *oldtd;
268
269 if (!proc0.p_stats)
270 panic("kthread_add called too soon");
271
272 /* If no process supplied, put it on proc0 */
273 if (p == NULL)
274 p = &proc0;
275
276 /* Initialize our new td */
277 newtd = thread_alloc(pages);
278 if (newtd == NULL)
279 return (ENOMEM);
280
281 PROC_LOCK(p);
282 if (p->p_state == PRS_ZOMBIE || (p->p_flag2 & P2_WEXIT) != 0) {
283 PROC_UNLOCK(p);
284 thread_free(newtd);
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