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("$FreeBSD$");
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
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 int
kproc_create(void (* func)(void *),void * arg,struct proc ** newpp,int flags,int pages,const char * fmt,...)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
kproc_exit(int ecode)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
kproc_suspend(struct proc * p,int timo)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
kproc_resume(struct proc * p)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
kproc_suspend_check(struct proc * p)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
kthread_start(const void * udata)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
kthread_add(void (* func)(void *),void * arg,struct proc * p,struct thread ** newtdp,int flags,int pages,const char * fmt,...)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 newtd->td_vslock_sz = 0;
278 bzero(&newtd->td_si, sizeof(newtd->td_si));
279 bcopy(&oldtd->td_startcopy, &newtd->td_startcopy,
280 __rangeof(struct thread, td_startcopy, td_endcopy));
281 newtd->td_sa = oldtd->td_sa;
282
283 /* set up arg0 for 'ps', et al */
284 va_start(ap, fmt);
285 vsnprintf(newtd->td_name, sizeof(newtd->td_name), fmt, ap);
286 va_end(ap);
287
288 newtd->td_proc = p; /* needed for cpu_copy_thread */
289 /* might be further optimized for kthread */
290 cpu_copy_thread(newtd, oldtd);
291 /* put the designated function(arg) as the resume context */
292 cpu_fork_kthread_handler(newtd, func, arg);
293
294 newtd->td_pflags |= TDP_KTHREAD;
295 thread_cow_get_proc(newtd, p);
296
297 /* this code almost the same as create_thread() in kern_thr.c */
298 p->p_flag |= P_HADTHREADS;
299 thread_link(newtd, p);
300 thread_lock(oldtd);
301 /* let the scheduler know about these things. */
302 sched_fork_thread(oldtd, newtd);
303 TD_SET_CAN_RUN(newtd);
304 thread_unlock(oldtd);
305 PROC_UNLOCK(p);
306
307 tidhash_add(newtd);
308
309 /* Avoid inheriting affinity from a random parent. */
310 cpuset_setthread(newtd->td_tid, cpuset_root);
311
312 /* Delay putting it on the run queue until now. */
313 if (!(flags & RFSTOPPED)) {
314 thread_lock(newtd);
315 sched_add(newtd, SRQ_BORING);
316 thread_unlock(newtd);
317 }
318 if (newtdp)
319 *newtdp = newtd;
320 return 0;
321 }
322
323 void
kthread_exit(void)324 kthread_exit(void)
325 {
326 struct proc *p;
327 struct thread *td;
328
329 td = curthread;
330 p = td->td_proc;
331
332 /* A module may be waiting for us to exit. */
333 wakeup(td);
334
335 /*
336 * The last exiting thread in a kernel process must tear down
337 * the whole process.
338 */
339 rw_wlock(&tidhash_lock);
340 PROC_LOCK(p);
341 if (p->p_numthreads == 1) {
342 PROC_UNLOCK(p);
343 rw_wunlock(&tidhash_lock);
344 kproc_exit(0);
345 }
346 LIST_REMOVE(td, td_hash);
347 rw_wunlock(&tidhash_lock);
348 umtx_thread_exit(td);
349 tdsigcleanup(td);
350 PROC_SLOCK(p);
351 thread_exit();
352 }
353
354 /*
355 * Advise a kernel process to suspend (or resume) in its main loop.
356 * Participation is voluntary.
357 */
358 int
kthread_suspend(struct thread * td,int timo)359 kthread_suspend(struct thread *td, int timo)
360 {
361 struct proc *p;
362
363 p = td->td_proc;
364
365 /*
366 * td_pflags should not be read by any thread other than
367 * curthread, but as long as this flag is invariant during the
368 * thread's lifetime, it is OK to check its state.
369 */
370 if ((td->td_pflags & TDP_KTHREAD) == 0)
371 return (EINVAL);
372
373 /*
374 * The caller of the primitive should have already checked that the
375 * thread is up and running, thus not being blocked by other
376 * conditions.
377 */
378 PROC_LOCK(p);
379 thread_lock(td);
380 td->td_flags |= TDF_KTH_SUSP;
381 thread_unlock(td);
382 return (msleep(&td->td_flags, &p->p_mtx, PPAUSE | PDROP, "suspkt",
383 timo));
384 }
385
386 /*
387 * Resume a thread previously put asleep with kthread_suspend().
388 */
389 int
kthread_resume(struct thread * td)390 kthread_resume(struct thread *td)
391 {
392 struct proc *p;
393
394 p = td->td_proc;
395
396 /*
397 * td_pflags should not be read by any thread other than
398 * curthread, but as long as this flag is invariant during the
399 * thread's lifetime, it is OK to check its state.
400 */
401 if ((td->td_pflags & TDP_KTHREAD) == 0)
402 return (EINVAL);
403
404 PROC_LOCK(p);
405 thread_lock(td);
406 td->td_flags &= ~TDF_KTH_SUSP;
407 thread_unlock(td);
408 wakeup(&td->td_flags);
409 PROC_UNLOCK(p);
410 return (0);
411 }
412
413 /*
414 * Used by the thread to poll as to whether it should yield/sleep
415 * and notify the caller that is has happened.
416 */
417 void
kthread_suspend_check(void)418 kthread_suspend_check(void)
419 {
420 struct proc *p;
421 struct thread *td;
422
423 td = curthread;
424 p = td->td_proc;
425
426 if ((td->td_pflags & TDP_KTHREAD) == 0)
427 panic("%s: curthread is not a valid kthread", __func__);
428
429 /*
430 * As long as the double-lock protection is used when accessing the
431 * TDF_KTH_SUSP flag, synchronizing the read operation via proc mutex
432 * is fine.
433 */
434 PROC_LOCK(p);
435 while (td->td_flags & TDF_KTH_SUSP) {
436 wakeup(&td->td_flags);
437 msleep(&td->td_flags, &p->p_mtx, PPAUSE, "ktsusp", 0);
438 }
439 PROC_UNLOCK(p);
440 }
441
442 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,...)443 kproc_kthread_add(void (*func)(void *), void *arg,
444 struct proc **procptr, struct thread **tdptr,
445 int flags, int pages, const char *procname, const char *fmt, ...)
446 {
447 int error;
448 va_list ap;
449 char buf[100];
450 struct thread *td;
451
452 if (*procptr == NULL) {
453 error = kproc_create(func, arg,
454 procptr, flags, pages, "%s", procname);
455 if (error)
456 return (error);
457 td = FIRST_THREAD_IN_PROC(*procptr);
458 if (tdptr)
459 *tdptr = td;
460 va_start(ap, fmt);
461 vsnprintf(td->td_name, sizeof(td->td_name), fmt, ap);
462 va_end(ap);
463 #ifdef KTR
464 sched_clear_tdname(td);
465 #endif
466 return (0);
467 }
468 va_start(ap, fmt);
469 vsnprintf(buf, sizeof(buf), fmt, ap);
470 va_end(ap);
471 error = kthread_add(func, arg, *procptr,
472 tdptr, flags, pages, "%s", buf);
473 return (error);
474 }
475