1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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/cdefs.h>
30 __FBSDID("$FreeBSD$");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/cpuset.h>
35 #include <sys/kthread.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/proc.h>
39 #include <sys/resourcevar.h>
40 #include <sys/rwlock.h>
41 #include <sys/signalvar.h>
42 #include <sys/sx.h>
43 #include <sys/umtx.h>
44 #include <sys/unistd.h>
45 #include <sys/wait.h>
46 #include <sys/sched.h>
47 #include <sys/tslog.h>
48 #include <vm/vm.h>
49 #include <vm/vm_extern.h>
50
51 #include <machine/stdarg.h>
52
53 /*
54 * Start a kernel process. This is called after a fork() call in
55 * mi_startup() in the file kern/init_main.c.
56 *
57 * This function is used to start "internal" daemons and intended
58 * to be called from SYSINIT().
59 */
60 void
61 kproc_start(const void *udata)
62 {
63 const struct kproc_desc *kp = udata;
64 int error;
65
66 error = kproc_create((void (*)(void *))kp->func, NULL,
67 kp->global_procpp, 0, 0, "%s", kp->arg0);
68 if (error)
69 panic("kproc_start: %s: error %d", kp->arg0, error);
70 }
71
72 /*
73 * Create a kernel process/thread/whatever. It shares its address space
74 * with proc0 - ie: kernel only.
75 *
76 * func is the function to start.
77 * arg is the parameter to pass to function on first startup.
78 * newpp is the return value pointing to the thread's struct proc.
79 * flags are flags to fork1 (in unistd.h)
80 * fmt and following will be *printf'd into (*newpp)->p_comm (for ps, etc.).
81 */
82 int
83 kproc_create(void (*func)(void *), void *arg,
84 struct proc **newpp, int flags, int pages, const char *fmt, ...)
85 {
86 struct fork_req fr;
87 int error;
88 va_list ap;
89 struct thread *td;
90 struct proc *p2;
91
92 if (!proc0.p_stats)
93 panic("kproc_create called too soon");
94
95 bzero(&fr, sizeof(fr));
96 fr.fr_flags = RFMEM | RFFDG | RFPROC | RFSTOPPED | flags;
97 fr.fr_pages = pages;
98 fr.fr_procp = &p2;
99 error = fork1(&thread0, &fr);
100 if (error)
101 return error;
102
103 /* save a global descriptor, if desired */
104 if (newpp != NULL)
105 *newpp = p2;
106
107 /* this is a non-swapped system process */
108 PROC_LOCK(p2);
109 td = FIRST_THREAD_IN_PROC(p2);
110 p2->p_flag |= P_SYSTEM | P_KPROC;
111 td->td_pflags |= TDP_KTHREAD;
112 mtx_lock(&p2->p_sigacts->ps_mtx);
113 p2->p_sigacts->ps_flag |= PS_NOCLDWAIT;
114 mtx_unlock(&p2->p_sigacts->ps_mtx);
115 PROC_UNLOCK(p2);
116
117 /* set up arg0 for 'ps', et al */
118 va_start(ap, fmt);
119 vsnprintf(p2->p_comm, sizeof(p2->p_comm), fmt, ap);
120 va_end(ap);
121 /* set up arg0 for 'ps', et al */
122 va_start(ap, fmt);
123 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
124 va_end(ap);
125 #ifdef KTR
126 sched_clear_tdname(td);
127 #endif
128 TSTHREAD(td, td->td_name);
129 #ifdef HWPMC_HOOKS
130 if (PMC_SYSTEM_SAMPLING_ACTIVE()) {
131 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_PROC_CREATE_LOG, p2);
132 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL);
133 }
134 #endif
135
136 /* call the processes' main()... */
137 cpu_fork_kthread_handler(td, func, arg);
138
139 /* Avoid inheriting affinity from a random parent. */
140 cpuset_kernthread(td);
141 thread_lock(td);
142 TD_SET_CAN_RUN(td);
143 sched_prio(td, PVM);
144 sched_user_prio(td, PUSER);
145
146 /* Delay putting it on the run queue until now. */
147 if (!(flags & RFSTOPPED))
148 sched_add(td, SRQ_BORING);
149 thread_unlock(td);
150
151 return 0;
152 }
153
154 void
155 kproc_exit(int ecode)
156 {
157 struct thread *td;
158 struct proc *p;
159
160 td = curthread;
161 p = td->td_proc;
162
163 /*
164 * Reparent curthread from proc0 to init so that the zombie
165 * is harvested.
166 */
167 sx_xlock(&proctree_lock);
168 PROC_LOCK(p);
169 proc_reparent(p, initproc, true);
170 PROC_UNLOCK(p);
171 sx_xunlock(&proctree_lock);
172
173 /*
174 * Wakeup anyone waiting for us to exit.
175 */
176 wakeup(p);
177
178 /* Buh-bye! */
179 exit1(td, ecode, 0);
180 }
181
182 /*
183 * Advise a kernel process to suspend (or resume) in its main loop.
184 * Participation is voluntary.
185 */
186 int
187 kproc_suspend(struct proc *p, int timo)
188 {
189 /*
190 * Make sure this is indeed a system process and we can safely
191 * use the p_siglist field.
192 */
193 PROC_LOCK(p);
194 if ((p->p_flag & P_KPROC) == 0) {
195 PROC_UNLOCK(p);
196 return (EINVAL);
197 }
198 SIGADDSET(p->p_siglist, SIGSTOP);
199 wakeup(p);
200 return msleep(&p->p_siglist, &p->p_mtx, PPAUSE | PDROP, "suspkp", timo);
201 }
202
203 int
204 kproc_resume(struct proc *p)
205 {
206 /*
207 * Make sure this is indeed a system process and we can safely
208 * use the p_siglist field.
209 */
210 PROC_LOCK(p);
211 if ((p->p_flag & P_KPROC) == 0) {
212 PROC_UNLOCK(p);
213 return (EINVAL);
214 }
215 SIGDELSET(p->p_siglist, SIGSTOP);
216 PROC_UNLOCK(p);
217 wakeup(&p->p_siglist);
218 return (0);
219 }
220
221 void
222 kproc_suspend_check(struct proc *p)
223 {
224 PROC_LOCK(p);
225 while (SIGISMEMBER(p->p_siglist, SIGSTOP)) {
226 wakeup(&p->p_siglist);
227 msleep(&p->p_siglist, &p->p_mtx, PPAUSE, "kpsusp", 0);
228 }
229 PROC_UNLOCK(p);
230 }
231
232
233 /*
234 * Start a kernel thread.
235 *
236 * This function is used to start "internal" daemons and intended
237 * to be called from SYSINIT().
238 */
239
240 void
241 kthread_start(const void *udata)
242 {
243 const struct kthread_desc *kp = udata;
244 int error;
245
246 error = kthread_add((void (*)(void *))kp->func, NULL,
247 NULL, kp->global_threadpp, 0, 0, "%s", kp->arg0);
248 if (error)
249 panic("kthread_start: %s: error %d", kp->arg0, error);
250 }
251
252 /*
253 * Create a kernel thread. It shares its address space
254 * with proc0 - ie: kernel only.
255 *
256 * func is the function to start.
257 * arg is the parameter to pass to function on first startup.
258 * newtdp is the return value pointing to the thread's struct thread.
259 * ** XXX fix this --> flags are flags to fork1 (in unistd.h)
260 * fmt and following will be *printf'd into (*newtd)->td_name (for ps, etc.).
261 */
262 int
263 kthread_add(void (*func)(void *), void *arg, struct proc *p,
264 struct thread **newtdp, int flags, int pages, const char *fmt, ...)
265 {
266 va_list ap;
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 oldtd = FIRST_THREAD_IN_PROC(p);
283
284 bzero(&newtd->td_startzero,
285 __rangeof(struct thread, td_startzero, td_endzero));
286 newtd->td_pflags2 = 0;
287 newtd->td_errno = 0;
288 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
289 __rangeof(struct thread, td_startcopy, td_endcopy));
290
291 /* set up arg0 for 'ps', et al */
292 va_start(ap, fmt);
293 vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap);
294 va_end(ap);
295
296 TSTHREAD(newtd, newtd->td_name);
297
298 newtd->td_proc = p; /* needed for cpu_copy_thread */
299 /* might be further optimized for kthread */
300 cpu_copy_thread(newtd, oldtd);
301 /* put the designated function(arg) as the resume context */
302 cpu_fork_kthread_handler(newtd, func, arg);
303
304 newtd->td_pflags |= TDP_KTHREAD;
305 thread_cow_get_proc(newtd, p);
306
307 /* this code almost the same as create_thread() in kern_thr.c */
308 p->p_flag |= P_HADTHREADS;
309 thread_link(newtd, p);
310 thread_lock(oldtd);
311 /* let the scheduler know about these things. */
312 sched_fork_thread(oldtd, newtd);
313 TD_SET_CAN_RUN(newtd);
314 thread_unlock(oldtd);
315 PROC_UNLOCK(p);
316
317 tidhash_add(newtd);
318
319 /* Avoid inheriting affinity from a random parent. */
320 cpuset_kernthread(newtd);
321 #ifdef HWPMC_HOOKS
322 if (PMC_SYSTEM_SAMPLING_ACTIVE())
323 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_CREATE_LOG, NULL);
324 #endif
325 /* Delay putting it on the run queue until now. */
326 if (!(flags & RFSTOPPED)) {
327 thread_lock(newtd);
328 sched_add(newtd, SRQ_BORING);
329 thread_unlock(newtd);
330 }
331 if (newtdp)
332 *newtdp = newtd;
333 return 0;
334 }
335
336 void
337 kthread_exit(void)
338 {
339 struct proc *p;
340 struct thread *td;
341
342 td = curthread;
343 p = td->td_proc;
344
345 #ifdef HWPMC_HOOKS
346 if (PMC_SYSTEM_SAMPLING_ACTIVE())
347 PMC_CALL_HOOK_UNLOCKED(td, PMC_FN_THR_EXIT_LOG, NULL);
348 #endif
349 /* A module may be waiting for us to exit. */
350 wakeup(td);
351
352 /*
353 * The last exiting thread in a kernel process must tear down
354 * the whole process.
355 */
356 rw_wlock(&tidhash_lock);
357 PROC_LOCK(p);
358 if (p->p_numthreads == 1) {
359 PROC_UNLOCK(p);
360 rw_wunlock(&tidhash_lock);
361 kproc_exit(0);
362 }
363 LIST_REMOVE(td, td_hash);
364 rw_wunlock(&tidhash_lock);
365 umtx_thread_exit(td);
366 tdsigcleanup(td);
367 PROC_SLOCK(p);
368 thread_exit();
369 }
370
371 /*
372 * Advise a kernel process to suspend (or resume) in its main loop.
373 * Participation is voluntary.
374 */
375 int
376 kthread_suspend(struct thread *td, int timo)
377 {
378 struct proc *p;
379
380 p = td->td_proc;
381
382 /*
383 * td_pflags should not be read by any thread other than
384 * curthread, but as long as this flag is invariant during the
385 * thread's lifetime, it is OK to check its state.
386 */
387 if ((td->td_pflags & TDP_KTHREAD) == 0)
388 return (EINVAL);
389
390 /*
391 * The caller of the primitive should have already checked that the
392 * thread is up and running, thus not being blocked by other
393 * conditions.
394 */
395 PROC_LOCK(p);
396 thread_lock(td);
397 td->td_flags |= TDF_KTH_SUSP;
398 thread_unlock(td);
399 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt",
400 timo));
401 }
402
403 /*
404 * Resume a thread previously put asleep with kthread_suspend().
405 */
406 int
407 kthread_resume(struct thread *td)
408 {
409 struct proc *p;
410
411 p = td->td_proc;
412
413 /*
414 * td_pflags should not be read by any thread other than
415 * curthread, but as long as this flag is invariant during the
416 * thread's lifetime, it is OK to check its state.
417 */
418 if ((td->td_pflags & TDP_KTHREAD) == 0)
419 return (EINVAL);
420
421 PROC_LOCK(p);
422 thread_lock(td);
423 td->td_flags &= ~TDF_KTH_SUSP;
424 thread_unlock(td);
425 wakeup(&td->td_flags);
426 PROC_UNLOCK(p);
427 return (0);
428 }
429
430 /*
431 * Used by the thread to poll as to whether it should yield/sleep
432 * and notify the caller that is has happened.
433 */
434 void
435 kthread_suspend_check(void)
436 {
437 struct proc *p;
438 struct thread *td;
439
440 td = curthread;
441 p = td->td_proc;
442
443 if ((td->td_pflags & TDP_KTHREAD) == 0)
444 panic("%s: curthread is not a valid kthread", __func__);
445
446 /*
447 * Setting the TDF_KTH_SUSP flag is protected by process lock.
448 *
449 * Do an unlocked read first to avoid serializing with all other threads
450 * in the common case of not suspending.
451 */
452 if ((td->td_flags & TDF_KTH_SUSP) == 0)
453 return;
454 PROC_LOCK(p);
455 while ((td->td_flags & TDF_KTH_SUSP) != 0) {
456 wakeup(&td->td_flags);
457 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0);
458 }
459 PROC_UNLOCK(p);
460 }
461
462 int
463 kproc_kthread_add(void (*func)(void *), void *arg,
464 struct proc **procptr, struct thread **tdptr,
465 int flags, int pages, const char *procname, const char *fmt, ...)
466 {
467 int error;
468 va_list ap;
469 char buf[100];
470 struct thread *td;
471
472 if (*procptr == NULL) {
473 error = kproc_create(func, arg,
474 procptr, flags, pages, "%s", procname);
475 if (error)
476 return (error);
477 td = FIRST_THREAD_IN_PROC(*procptr);
478 if (tdptr)
479 *tdptr = td;
480 va_start(ap, fmt);
481 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
482 va_end(ap);
483 #ifdef KTR
484 sched_clear_tdname(td);
485 #endif
486 return (0);
487 }
488 va_start(ap, fmt);
489 vsnprintf(buf, sizeof(buf), fmt, ap);
490 va_end(ap);
491 error = kthread_add(func, arg, *procptr,
492 tdptr, flags, pages, "%s", buf);
493 return (error);
494 }
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