FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_kse.c
1 /*-
2 * Copyright (C) 2001 Julian Elischer <julian@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(s), this list of conditions and the following disclaimer as
10 * the first lines of this file unmodified other than the possible
11 * addition of one or more copyright notices.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice(s), 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 COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
17 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
20 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
23 * 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 SUCH
26 * DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: releng/6.1/sys/kern/kern_kse.c 158179 2006-04-30 16:44:43Z cvs2svn $");
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
35 #include <sys/imgact.h>
36 #include <sys/lock.h>
37 #include <sys/mutex.h>
38 #include <sys/proc.h>
39 #include <sys/ptrace.h>
40 #include <sys/smp.h>
41 #include <sys/syscallsubr.h>
42 #include <sys/sysproto.h>
43 #include <sys/sched.h>
44 #include <sys/signalvar.h>
45 #include <sys/sleepqueue.h>
46 #include <sys/kse.h>
47 #include <sys/ktr.h>
48 #include <vm/uma.h>
49
50 /*
51 * KSEGRP related storage.
52 */
53 static uma_zone_t upcall_zone;
54
55 /* DEBUG ONLY */
56 extern int virtual_cpu;
57 extern int thread_debug;
58
59 extern int max_threads_per_proc;
60 extern int max_groups_per_proc;
61 extern int max_threads_hits;
62 extern struct mtx kse_zombie_lock;
63
64
65 TAILQ_HEAD(, kse_upcall) zombie_upcalls =
66 TAILQ_HEAD_INITIALIZER(zombie_upcalls);
67
68 static int thread_update_usr_ticks(struct thread *td);
69 static void thread_alloc_spare(struct thread *td);
70
71 struct kse_upcall *
72 upcall_alloc(void)
73 {
74 struct kse_upcall *ku;
75
76 ku = uma_zalloc(upcall_zone, M_WAITOK | M_ZERO);
77 return (ku);
78 }
79
80 void
81 upcall_free(struct kse_upcall *ku)
82 {
83
84 uma_zfree(upcall_zone, ku);
85 }
86
87 void
88 upcall_link(struct kse_upcall *ku, struct ksegrp *kg)
89 {
90
91 mtx_assert(&sched_lock, MA_OWNED);
92 TAILQ_INSERT_TAIL(&kg->kg_upcalls, ku, ku_link);
93 ku->ku_ksegrp = kg;
94 kg->kg_numupcalls++;
95 }
96
97 void
98 upcall_unlink(struct kse_upcall *ku)
99 {
100 struct ksegrp *kg = ku->ku_ksegrp;
101
102 mtx_assert(&sched_lock, MA_OWNED);
103 KASSERT(ku->ku_owner == NULL, ("%s: have owner", __func__));
104 TAILQ_REMOVE(&kg->kg_upcalls, ku, ku_link);
105 kg->kg_numupcalls--;
106 upcall_stash(ku);
107 }
108
109 void
110 upcall_remove(struct thread *td)
111 {
112
113 mtx_assert(&sched_lock, MA_OWNED);
114 if (td->td_upcall != NULL) {
115 td->td_upcall->ku_owner = NULL;
116 upcall_unlink(td->td_upcall);
117 td->td_upcall = NULL;
118 }
119 }
120
121 #ifndef _SYS_SYSPROTO_H_
122 struct kse_switchin_args {
123 struct kse_thr_mailbox *tmbx;
124 int flags;
125 };
126 #endif
127
128 int
129 kse_switchin(struct thread *td, struct kse_switchin_args *uap)
130 {
131 struct kse_thr_mailbox tmbx;
132 struct kse_upcall *ku;
133 int error;
134
135 if ((ku = td->td_upcall) == NULL || TD_CAN_UNBIND(td))
136 return (EINVAL);
137 error = (uap->tmbx == NULL) ? EINVAL : 0;
138 if (!error)
139 error = copyin(uap->tmbx, &tmbx, sizeof(tmbx));
140 if (!error && (uap->flags & KSE_SWITCHIN_SETTMBX))
141 error = (suword(&ku->ku_mailbox->km_curthread,
142 (long)uap->tmbx) != 0 ? EINVAL : 0);
143 if (!error)
144 error = set_mcontext(td, &tmbx.tm_context.uc_mcontext);
145 if (!error) {
146 suword32(&uap->tmbx->tm_lwp, td->td_tid);
147 if (uap->flags & KSE_SWITCHIN_SETTMBX) {
148 td->td_mailbox = uap->tmbx;
149 td->td_pflags |= TDP_CAN_UNBIND;
150 }
151 PROC_LOCK(td->td_proc);
152 if (td->td_proc->p_flag & P_TRACED) {
153 _PHOLD(td->td_proc);
154 if (tmbx.tm_dflags & TMDF_SSTEP)
155 ptrace_single_step(td);
156 else
157 ptrace_clear_single_step(td);
158 if (tmbx.tm_dflags & TMDF_SUSPEND) {
159 mtx_lock_spin(&sched_lock);
160 /* fuword can block, check again */
161 if (td->td_upcall)
162 ku->ku_flags |= KUF_DOUPCALL;
163 mtx_unlock_spin(&sched_lock);
164 }
165 _PRELE(td->td_proc);
166 }
167 PROC_UNLOCK(td->td_proc);
168 }
169 return ((error == 0) ? EJUSTRETURN : error);
170 }
171
172 /*
173 struct kse_thr_interrupt_args {
174 struct kse_thr_mailbox * tmbx;
175 int cmd;
176 long data;
177 };
178 */
179 int
180 kse_thr_interrupt(struct thread *td, struct kse_thr_interrupt_args *uap)
181 {
182 struct kse_execve_args args;
183 struct image_args iargs;
184 struct proc *p;
185 struct thread *td2;
186 struct kse_upcall *ku;
187 struct kse_thr_mailbox *tmbx;
188 uint32_t flags;
189 int error;
190
191 p = td->td_proc;
192
193 if (!(p->p_flag & P_SA))
194 return (EINVAL);
195
196 switch (uap->cmd) {
197 case KSE_INTR_SENDSIG:
198 if (uap->data < 0 || uap->data > _SIG_MAXSIG)
199 return (EINVAL);
200 case KSE_INTR_INTERRUPT:
201 case KSE_INTR_RESTART:
202 PROC_LOCK(p);
203 mtx_lock_spin(&sched_lock);
204 FOREACH_THREAD_IN_PROC(p, td2) {
205 if (td2->td_mailbox == uap->tmbx)
206 break;
207 }
208 if (td2 == NULL) {
209 mtx_unlock_spin(&sched_lock);
210 PROC_UNLOCK(p);
211 return (ESRCH);
212 }
213 if (uap->cmd == KSE_INTR_SENDSIG) {
214 if (uap->data > 0) {
215 td2->td_flags &= ~TDF_INTERRUPT;
216 mtx_unlock_spin(&sched_lock);
217 tdsignal(td2, (int)uap->data, SIGTARGET_TD);
218 } else {
219 mtx_unlock_spin(&sched_lock);
220 }
221 } else {
222 td2->td_flags |= TDF_INTERRUPT | TDF_ASTPENDING;
223 if (TD_CAN_UNBIND(td2))
224 td2->td_upcall->ku_flags |= KUF_DOUPCALL;
225 if (uap->cmd == KSE_INTR_INTERRUPT)
226 td2->td_intrval = EINTR;
227 else
228 td2->td_intrval = ERESTART;
229 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR))
230 sleepq_abort(td2, td2->td_intrval);
231 mtx_unlock_spin(&sched_lock);
232 }
233 PROC_UNLOCK(p);
234 break;
235 case KSE_INTR_SIGEXIT:
236 if (uap->data < 1 || uap->data > _SIG_MAXSIG)
237 return (EINVAL);
238 PROC_LOCK(p);
239 sigexit(td, (int)uap->data);
240 break;
241
242 case KSE_INTR_DBSUSPEND:
243 /* this sub-function is only for bound thread */
244 if (td->td_pflags & TDP_SA)
245 return (EINVAL);
246 ku = td->td_upcall;
247 tmbx = (void *)fuword((void *)&ku->ku_mailbox->km_curthread);
248 if (tmbx == NULL || tmbx == (void *)-1)
249 return (EINVAL);
250 flags = 0;
251 while ((p->p_flag & P_TRACED) && !(p->p_flag & P_SINGLE_EXIT)) {
252 flags = fuword32(&tmbx->tm_dflags);
253 if (!(flags & TMDF_SUSPEND))
254 break;
255 PROC_LOCK(p);
256 mtx_lock_spin(&sched_lock);
257 thread_stopped(p);
258 thread_suspend_one(td);
259 PROC_UNLOCK(p);
260 mi_switch(SW_VOL, NULL);
261 mtx_unlock_spin(&sched_lock);
262 }
263 return (0);
264
265 case KSE_INTR_EXECVE:
266 error = copyin((void *)uap->data, &args, sizeof(args));
267 if (error)
268 return (error);
269 error = exec_copyin_args(&iargs, args.path, UIO_USERSPACE,
270 args.argv, args.envp);
271 if (error == 0)
272 error = kern_execve(td, &iargs, NULL);
273 exec_free_args(&iargs);
274 if (error == 0) {
275 PROC_LOCK(p);
276 SIGSETOR(td->td_siglist, args.sigpend);
277 PROC_UNLOCK(p);
278 kern_sigprocmask(td, SIG_SETMASK, &args.sigmask, NULL,
279 0);
280 }
281 return (error);
282
283 default:
284 return (EINVAL);
285 }
286 return (0);
287 }
288
289 /*
290 struct kse_exit_args {
291 register_t dummy;
292 };
293 */
294 int
295 kse_exit(struct thread *td, struct kse_exit_args *uap)
296 {
297 struct proc *p;
298 struct ksegrp *kg;
299 struct kse_upcall *ku, *ku2;
300 int error, count;
301
302 p = td->td_proc;
303 /*
304 * Ensure that this is only called from the UTS
305 */
306 if ((ku = td->td_upcall) == NULL || TD_CAN_UNBIND(td))
307 return (EINVAL);
308
309 kg = td->td_ksegrp;
310 count = 0;
311
312 /*
313 * Calculate the existing non-exiting upcalls in this ksegroup.
314 * If we are the last upcall but there are still other threads,
315 * then do not exit. We need the other threads to be able to
316 * complete whatever they are doing.
317 * XXX This relies on the userland knowing what to do if we return.
318 * It may be a better choice to convert ourselves into a kse_release
319 * ( or similar) and wait in the kernel to be needed.
320 */
321 PROC_LOCK(p);
322 mtx_lock_spin(&sched_lock);
323 FOREACH_UPCALL_IN_GROUP(kg, ku2) {
324 if (ku2->ku_flags & KUF_EXITING)
325 count++;
326 }
327 if ((kg->kg_numupcalls - count) == 1 &&
328 (kg->kg_numthreads > 1)) {
329 mtx_unlock_spin(&sched_lock);
330 PROC_UNLOCK(p);
331 return (EDEADLK);
332 }
333 ku->ku_flags |= KUF_EXITING;
334 mtx_unlock_spin(&sched_lock);
335 PROC_UNLOCK(p);
336
337 /*
338 * Mark the UTS mailbox as having been finished with.
339 * If that fails then just go for a segfault.
340 * XXX need to check it that can be deliverred without a mailbox.
341 */
342 error = suword32(&ku->ku_mailbox->km_flags, ku->ku_mflags|KMF_DONE);
343 if (!(td->td_pflags & TDP_SA))
344 if (suword32(&td->td_mailbox->tm_lwp, 0))
345 error = EFAULT;
346 PROC_LOCK(p);
347 if (error)
348 psignal(p, SIGSEGV);
349 mtx_lock_spin(&sched_lock);
350 upcall_remove(td);
351 if (p->p_numthreads != 1) {
352 /*
353 * If we are not the last thread, but we are the last
354 * thread in this ksegrp, then by definition this is not
355 * the last group and we need to clean it up as well.
356 * thread_exit will clean up the kseg as needed.
357 */
358 thread_stopped(p);
359 thread_exit();
360 /* NOTREACHED */
361 }
362 /*
363 * This is the last thread. Just return to the user.
364 * We know that there is only one ksegrp too, as any others
365 * would have been discarded in previous calls to thread_exit().
366 * Effectively we have left threading mode..
367 * The only real thing left to do is ensure that the
368 * scheduler sets out concurrency back to 1 as that may be a
369 * resource leak otherwise.
370 * This is an A[PB]I issue.. what SHOULD we do?
371 * One possibility is to return to the user. It may not cope well.
372 * The other possibility would be to let the process exit.
373 */
374 thread_unthread(td);
375 mtx_unlock_spin(&sched_lock);
376 PROC_UNLOCK(p);
377 #if 1
378 return (0);
379 #else
380 exit1(td, 0);
381 #endif
382 }
383
384 /*
385 * Either becomes an upcall or waits for an awakening event and
386 * then becomes an upcall. Only error cases return.
387 */
388 /*
389 struct kse_release_args {
390 struct timespec *timeout;
391 };
392 */
393 int
394 kse_release(struct thread *td, struct kse_release_args *uap)
395 {
396 struct proc *p;
397 struct ksegrp *kg;
398 struct kse_upcall *ku;
399 struct timespec timeout;
400 struct timeval tv;
401 sigset_t sigset;
402 int error;
403
404 p = td->td_proc;
405 kg = td->td_ksegrp;
406 if ((ku = td->td_upcall) == NULL || TD_CAN_UNBIND(td))
407 return (EINVAL);
408 if (uap->timeout != NULL) {
409 if ((error = copyin(uap->timeout, &timeout, sizeof(timeout))))
410 return (error);
411 TIMESPEC_TO_TIMEVAL(&tv, &timeout);
412 }
413 if (td->td_pflags & TDP_SA)
414 td->td_pflags |= TDP_UPCALLING;
415 else {
416 ku->ku_mflags = fuword32(&ku->ku_mailbox->km_flags);
417 if (ku->ku_mflags == -1) {
418 PROC_LOCK(p);
419 sigexit(td, SIGSEGV);
420 }
421 }
422 PROC_LOCK(p);
423 if (ku->ku_mflags & KMF_WAITSIGEVENT) {
424 /* UTS wants to wait for signal event */
425 if (!(p->p_flag & P_SIGEVENT) &&
426 !(ku->ku_flags & KUF_DOUPCALL)) {
427 td->td_kflags |= TDK_KSERELSIG;
428 error = msleep(&p->p_siglist, &p->p_mtx, PPAUSE|PCATCH,
429 "ksesigwait", (uap->timeout ? tvtohz(&tv) : 0));
430 td->td_kflags &= ~(TDK_KSERELSIG | TDK_WAKEUP);
431 }
432 p->p_flag &= ~P_SIGEVENT;
433 sigset = p->p_siglist;
434 PROC_UNLOCK(p);
435 error = copyout(&sigset, &ku->ku_mailbox->km_sigscaught,
436 sizeof(sigset));
437 } else {
438 if ((ku->ku_flags & KUF_DOUPCALL) == 0 &&
439 ((ku->ku_mflags & KMF_NOCOMPLETED) ||
440 (kg->kg_completed == NULL))) {
441 kg->kg_upsleeps++;
442 td->td_kflags |= TDK_KSEREL;
443 error = msleep(&kg->kg_completed, &p->p_mtx,
444 PPAUSE|PCATCH, "kserel",
445 (uap->timeout ? tvtohz(&tv) : 0));
446 td->td_kflags &= ~(TDK_KSEREL | TDK_WAKEUP);
447 kg->kg_upsleeps--;
448 }
449 PROC_UNLOCK(p);
450 }
451 if (ku->ku_flags & KUF_DOUPCALL) {
452 mtx_lock_spin(&sched_lock);
453 ku->ku_flags &= ~KUF_DOUPCALL;
454 mtx_unlock_spin(&sched_lock);
455 }
456 return (0);
457 }
458
459 /* struct kse_wakeup_args {
460 struct kse_mailbox *mbx;
461 }; */
462 int
463 kse_wakeup(struct thread *td, struct kse_wakeup_args *uap)
464 {
465 struct proc *p;
466 struct ksegrp *kg;
467 struct kse_upcall *ku;
468 struct thread *td2;
469
470 p = td->td_proc;
471 td2 = NULL;
472 ku = NULL;
473 /* KSE-enabled processes only, please. */
474 if (!(p->p_flag & P_SA))
475 return (EINVAL);
476 PROC_LOCK(p);
477 mtx_lock_spin(&sched_lock);
478 if (uap->mbx) {
479 FOREACH_KSEGRP_IN_PROC(p, kg) {
480 FOREACH_UPCALL_IN_GROUP(kg, ku) {
481 if (ku->ku_mailbox == uap->mbx)
482 break;
483 }
484 if (ku)
485 break;
486 }
487 } else {
488 kg = td->td_ksegrp;
489 if (kg->kg_upsleeps) {
490 mtx_unlock_spin(&sched_lock);
491 wakeup(&kg->kg_completed);
492 PROC_UNLOCK(p);
493 return (0);
494 }
495 ku = TAILQ_FIRST(&kg->kg_upcalls);
496 }
497 if (ku == NULL) {
498 mtx_unlock_spin(&sched_lock);
499 PROC_UNLOCK(p);
500 return (ESRCH);
501 }
502 if ((td2 = ku->ku_owner) == NULL) {
503 mtx_unlock_spin(&sched_lock);
504 panic("%s: no owner", __func__);
505 } else if (td2->td_kflags & (TDK_KSEREL | TDK_KSERELSIG)) {
506 mtx_unlock_spin(&sched_lock);
507 if (!(td2->td_kflags & TDK_WAKEUP)) {
508 td2->td_kflags |= TDK_WAKEUP;
509 if (td2->td_kflags & TDK_KSEREL)
510 sleepq_remove(td2, &kg->kg_completed);
511 else
512 sleepq_remove(td2, &p->p_siglist);
513 }
514 } else {
515 ku->ku_flags |= KUF_DOUPCALL;
516 mtx_unlock_spin(&sched_lock);
517 }
518 PROC_UNLOCK(p);
519 return (0);
520 }
521
522 /*
523 * No new KSEG: first call: use current KSE, don't schedule an upcall
524 * All other situations, do allocate max new KSEs and schedule an upcall.
525 *
526 * XXX should be changed so that 'first' behaviour lasts for as long
527 * as you have not made a kse in this ksegrp. i.e. as long as we do not have
528 * a mailbox..
529 */
530 /* struct kse_create_args {
531 struct kse_mailbox *mbx;
532 int newgroup;
533 }; */
534 int
535 kse_create(struct thread *td, struct kse_create_args *uap)
536 {
537 struct ksegrp *newkg;
538 struct ksegrp *kg;
539 struct proc *p;
540 struct kse_mailbox mbx;
541 struct kse_upcall *newku;
542 int err, ncpus, sa = 0, first = 0;
543 struct thread *newtd;
544
545 p = td->td_proc;
546 kg = td->td_ksegrp;
547 if ((err = copyin(uap->mbx, &mbx, sizeof(mbx))))
548 return (err);
549
550 ncpus = mp_ncpus;
551 if (virtual_cpu != 0)
552 ncpus = virtual_cpu;
553 /*
554 * If the new UTS mailbox says that this
555 * will be a BOUND lwp, then it had better
556 * have its thread mailbox already there.
557 * In addition, this ksegrp will be limited to
558 * a concurrency of 1. There is more on this later.
559 */
560 if (mbx.km_flags & KMF_BOUND) {
561 if (mbx.km_curthread == NULL)
562 return (EINVAL);
563 ncpus = 1;
564 } else {
565 sa = TDP_SA;
566 }
567
568 PROC_LOCK(p);
569 /*
570 * Processes using the other threading model can't
571 * suddenly start calling this one
572 */
573 if ((p->p_flag & (P_SA|P_HADTHREADS)) == P_HADTHREADS) {
574 PROC_UNLOCK(p);
575 return (EINVAL);
576 }
577
578 /*
579 * Limit it to NCPU upcall contexts per ksegrp in any case.
580 * There is a small race here as we don't hold proclock
581 * until we inc the ksegrp count, but it's not really a big problem
582 * if we get one too many, but we save a proc lock.
583 */
584 if ((!uap->newgroup) && (kg->kg_numupcalls >= ncpus)) {
585 PROC_UNLOCK(p);
586 return (EPROCLIM);
587 }
588
589 if (!(p->p_flag & P_SA)) {
590 first = 1;
591 p->p_flag |= P_SA|P_HADTHREADS;
592 }
593
594 PROC_UNLOCK(p);
595 /*
596 * Now pay attention!
597 * If we are going to be bound, then we need to be either
598 * a new group, or the first call ever. In either
599 * case we will be creating (or be) the only thread in a group.
600 * and the concurrency will be set to 1.
601 * This is not quite right, as we may still make ourself
602 * bound after making other ksegrps but it will do for now.
603 * The library will only try do this much.
604 */
605 if (!sa && !(uap->newgroup || first))
606 return (EINVAL);
607
608 if (uap->newgroup) {
609 newkg = ksegrp_alloc();
610 bzero(&newkg->kg_startzero,
611 __rangeof(struct ksegrp, kg_startzero, kg_endzero));
612 bcopy(&kg->kg_startcopy, &newkg->kg_startcopy,
613 __rangeof(struct ksegrp, kg_startcopy, kg_endcopy));
614 sched_init_concurrency(newkg);
615 PROC_LOCK(p);
616 if (p->p_numksegrps >= max_groups_per_proc) {
617 PROC_UNLOCK(p);
618 ksegrp_free(newkg);
619 return (EPROCLIM);
620 }
621 ksegrp_link(newkg, p);
622 mtx_lock_spin(&sched_lock);
623 sched_fork_ksegrp(td, newkg);
624 mtx_unlock_spin(&sched_lock);
625 PROC_UNLOCK(p);
626 } else {
627 /*
628 * We want to make a thread in our own ksegrp.
629 * If we are just the first call, either kind
630 * is ok, but if not then either we must be
631 * already an upcallable thread to make another,
632 * or a bound thread to make one of those.
633 * Once again, not quite right but good enough for now.. XXXKSE
634 */
635 if (!first && ((td->td_pflags & TDP_SA) != sa))
636 return (EINVAL);
637
638 newkg = kg;
639 }
640
641 /*
642 * This test is a bit "indirect".
643 * It might simplify things if we made a direct way of testing
644 * if a ksegrp has been worked on before.
645 * In the case of a bound request and the concurrency being set to
646 * one, the concurrency will already be 1 so it's just inefficient
647 * but not dangerous to call this again. XXX
648 */
649 if (newkg->kg_numupcalls == 0) {
650 /*
651 * Initialize KSE group with the appropriate
652 * concurrency.
653 *
654 * For a multiplexed group, create as as much concurrency
655 * as the number of physical cpus.
656 * This increases concurrency in the kernel even if the
657 * userland is not MP safe and can only run on a single CPU.
658 * In an ideal world, every physical cpu should execute a
659 * thread. If there is enough concurrency, threads in the
660 * kernel can be executed parallel on different cpus at
661 * full speed without being restricted by the number of
662 * upcalls the userland provides.
663 * Adding more upcall structures only increases concurrency
664 * in userland.
665 *
666 * For a bound thread group, because there is only one thread
667 * in the group, we only set the concurrency for the group
668 * to 1. A thread in this kind of group will never schedule
669 * an upcall when blocked. This simulates pthread system
670 * scope thread behaviour.
671 */
672 sched_set_concurrency(newkg, ncpus);
673 }
674 /*
675 * Even bound LWPs get a mailbox and an upcall to hold it.
676 */
677 newku = upcall_alloc();
678 newku->ku_mailbox = uap->mbx;
679 newku->ku_func = mbx.km_func;
680 bcopy(&mbx.km_stack, &newku->ku_stack, sizeof(stack_t));
681
682 /*
683 * For the first call this may not have been set.
684 * Of course nor may it actually be needed.
685 */
686 if (td->td_standin == NULL)
687 thread_alloc_spare(td);
688
689 PROC_LOCK(p);
690 mtx_lock_spin(&sched_lock);
691 if (newkg->kg_numupcalls >= ncpus) {
692 mtx_unlock_spin(&sched_lock);
693 PROC_UNLOCK(p);
694 upcall_free(newku);
695 return (EPROCLIM);
696 }
697
698 /*
699 * If we are the first time, and a normal thread,
700 * then transfer all the signals back to the 'process'.
701 * SA threading will make a special thread to handle them.
702 */
703 if (first && sa) {
704 SIGSETOR(p->p_siglist, td->td_siglist);
705 SIGEMPTYSET(td->td_siglist);
706 SIGFILLSET(td->td_sigmask);
707 SIG_CANTMASK(td->td_sigmask);
708 }
709
710 /*
711 * Make the new upcall available to the ksegrp.
712 * It may or may not use it, but it's available.
713 */
714 upcall_link(newku, newkg);
715 PROC_UNLOCK(p);
716 if (mbx.km_quantum)
717 newkg->kg_upquantum = max(1, mbx.km_quantum / tick);
718
719 /*
720 * Each upcall structure has an owner thread, find which
721 * one owns it.
722 */
723 if (uap->newgroup) {
724 /*
725 * Because the new ksegrp hasn't a thread,
726 * create an initial upcall thread to own it.
727 */
728 newtd = thread_schedule_upcall(td, newku);
729 } else {
730 /*
731 * If the current thread hasn't an upcall structure,
732 * just assign the upcall to it.
733 * It'll just return.
734 */
735 if (td->td_upcall == NULL) {
736 newku->ku_owner = td;
737 td->td_upcall = newku;
738 newtd = td;
739 } else {
740 /*
741 * Create a new upcall thread to own it.
742 */
743 newtd = thread_schedule_upcall(td, newku);
744 }
745 }
746 mtx_unlock_spin(&sched_lock);
747
748 /*
749 * Let the UTS instance know its LWPID.
750 * It doesn't really care. But the debugger will.
751 */
752 suword32(&newku->ku_mailbox->km_lwp, newtd->td_tid);
753
754 /*
755 * In the same manner, if the UTS has a current user thread,
756 * then it is also running on this LWP so set it as well.
757 * The library could do that of course.. but why not..
758 */
759 if (mbx.km_curthread)
760 suword32(&mbx.km_curthread->tm_lwp, newtd->td_tid);
761
762
763 if (sa) {
764 newtd->td_pflags |= TDP_SA;
765 } else {
766 newtd->td_pflags &= ~TDP_SA;
767
768 /*
769 * Since a library will use the mailbox pointer to
770 * identify even a bound thread, and the mailbox pointer
771 * will never be allowed to change after this syscall
772 * for a bound thread, set it here so the library can
773 * find the thread after the syscall returns.
774 */
775 newtd->td_mailbox = mbx.km_curthread;
776
777 if (newtd != td) {
778 /*
779 * If we did create a new thread then
780 * make sure it goes to the right place
781 * when it starts up, and make sure that it runs
782 * at full speed when it gets there.
783 * thread_schedule_upcall() copies all cpu state
784 * to the new thread, so we should clear single step
785 * flag here.
786 */
787 cpu_set_upcall_kse(newtd, newku->ku_func,
788 newku->ku_mailbox, &newku->ku_stack);
789 PROC_LOCK(p);
790 if (p->p_flag & P_TRACED) {
791 _PHOLD(p);
792 ptrace_clear_single_step(newtd);
793 _PRELE(p);
794 }
795 PROC_UNLOCK(p);
796 }
797 }
798
799 /*
800 * If we are starting a new thread, kick it off.
801 */
802 if (newtd != td) {
803 mtx_lock_spin(&sched_lock);
804 setrunqueue(newtd, SRQ_BORING);
805 mtx_unlock_spin(&sched_lock);
806 }
807 return (0);
808 }
809
810 /*
811 * Initialize global thread allocation resources.
812 */
813 void
814 kseinit(void)
815 {
816
817 upcall_zone = uma_zcreate("UPCALL", sizeof(struct kse_upcall),
818 NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
819 }
820
821 /*
822 * Stash an embarasingly extra upcall into the zombie upcall queue.
823 */
824
825 void
826 upcall_stash(struct kse_upcall *ku)
827 {
828 mtx_lock_spin(&kse_zombie_lock);
829 TAILQ_INSERT_HEAD(&zombie_upcalls, ku, ku_link);
830 mtx_unlock_spin(&kse_zombie_lock);
831 }
832
833 /*
834 * Reap zombie kse resource.
835 */
836 void
837 kse_GC(void)
838 {
839 struct kse_upcall *ku_first, *ku_next;
840
841 /*
842 * Don't even bother to lock if none at this instant,
843 * we really don't care about the next instant..
844 */
845 if (!TAILQ_EMPTY(&zombie_upcalls)) {
846 mtx_lock_spin(&kse_zombie_lock);
847 ku_first = TAILQ_FIRST(&zombie_upcalls);
848 if (ku_first)
849 TAILQ_INIT(&zombie_upcalls);
850 mtx_unlock_spin(&kse_zombie_lock);
851 while (ku_first) {
852 ku_next = TAILQ_NEXT(ku_first, ku_link);
853 upcall_free(ku_first);
854 ku_first = ku_next;
855 }
856 }
857 }
858
859 /*
860 * Store the thread context in the UTS's mailbox.
861 * then add the mailbox at the head of a list we are building in user space.
862 * The list is anchored in the ksegrp structure.
863 */
864 int
865 thread_export_context(struct thread *td, int willexit)
866 {
867 struct proc *p;
868 struct ksegrp *kg;
869 uintptr_t mbx;
870 void *addr;
871 int error = 0, sig;
872 mcontext_t mc;
873
874 p = td->td_proc;
875 kg = td->td_ksegrp;
876
877 /*
878 * Post sync signal, or process SIGKILL and SIGSTOP.
879 * For sync signal, it is only possible when the signal is not
880 * caught by userland or process is being debugged.
881 */
882 PROC_LOCK(p);
883 if (td->td_flags & TDF_NEEDSIGCHK) {
884 mtx_lock_spin(&sched_lock);
885 td->td_flags &= ~TDF_NEEDSIGCHK;
886 mtx_unlock_spin(&sched_lock);
887 mtx_lock(&p->p_sigacts->ps_mtx);
888 while ((sig = cursig(td)) != 0)
889 postsig(sig);
890 mtx_unlock(&p->p_sigacts->ps_mtx);
891 }
892 if (willexit)
893 SIGFILLSET(td->td_sigmask);
894 PROC_UNLOCK(p);
895
896 /* Export the user/machine context. */
897 get_mcontext(td, &mc, 0);
898 addr = (void *)(&td->td_mailbox->tm_context.uc_mcontext);
899 error = copyout(&mc, addr, sizeof(mcontext_t));
900 if (error)
901 goto bad;
902
903 addr = (caddr_t)(&td->td_mailbox->tm_lwp);
904 if (suword32(addr, 0)) {
905 error = EFAULT;
906 goto bad;
907 }
908
909 /* Get address in latest mbox of list pointer */
910 addr = (void *)(&td->td_mailbox->tm_next);
911 /*
912 * Put the saved address of the previous first
913 * entry into this one
914 */
915 for (;;) {
916 mbx = (uintptr_t)kg->kg_completed;
917 if (suword(addr, mbx)) {
918 error = EFAULT;
919 goto bad;
920 }
921 PROC_LOCK(p);
922 if (mbx == (uintptr_t)kg->kg_completed) {
923 kg->kg_completed = td->td_mailbox;
924 /*
925 * The thread context may be taken away by
926 * other upcall threads when we unlock
927 * process lock. it's no longer valid to
928 * use it again in any other places.
929 */
930 td->td_mailbox = NULL;
931 PROC_UNLOCK(p);
932 break;
933 }
934 PROC_UNLOCK(p);
935 }
936 td->td_usticks = 0;
937 return (0);
938
939 bad:
940 PROC_LOCK(p);
941 sigexit(td, SIGILL);
942 return (error);
943 }
944
945 /*
946 * Take the list of completed mailboxes for this KSEGRP and put them on this
947 * upcall's mailbox as it's the next one going up.
948 */
949 static int
950 thread_link_mboxes(struct ksegrp *kg, struct kse_upcall *ku)
951 {
952 struct proc *p = kg->kg_proc;
953 void *addr;
954 uintptr_t mbx;
955
956 addr = (void *)(&ku->ku_mailbox->km_completed);
957 for (;;) {
958 mbx = (uintptr_t)kg->kg_completed;
959 if (suword(addr, mbx)) {
960 PROC_LOCK(p);
961 psignal(p, SIGSEGV);
962 PROC_UNLOCK(p);
963 return (EFAULT);
964 }
965 PROC_LOCK(p);
966 if (mbx == (uintptr_t)kg->kg_completed) {
967 kg->kg_completed = NULL;
968 PROC_UNLOCK(p);
969 break;
970 }
971 PROC_UNLOCK(p);
972 }
973 return (0);
974 }
975
976 /*
977 * This function should be called at statclock interrupt time
978 */
979 int
980 thread_statclock(int user)
981 {
982 struct thread *td = curthread;
983
984 if (!(td->td_pflags & TDP_SA))
985 return (0);
986 if (user) {
987 /* Current always do via ast() */
988 mtx_lock_spin(&sched_lock);
989 td->td_flags |= TDF_ASTPENDING;
990 mtx_unlock_spin(&sched_lock);
991 td->td_uuticks++;
992 } else if (td->td_mailbox != NULL)
993 td->td_usticks++;
994 return (0);
995 }
996
997 /*
998 * Export state clock ticks for userland
999 */
1000 static int
1001 thread_update_usr_ticks(struct thread *td)
1002 {
1003 struct proc *p = td->td_proc;
1004 caddr_t addr;
1005 u_int uticks;
1006
1007 if (td->td_mailbox == NULL)
1008 return (-1);
1009
1010 if ((uticks = td->td_uuticks) != 0) {
1011 td->td_uuticks = 0;
1012 addr = (caddr_t)&td->td_mailbox->tm_uticks;
1013 if (suword32(addr, uticks+fuword32(addr)))
1014 goto error;
1015 }
1016 if ((uticks = td->td_usticks) != 0) {
1017 td->td_usticks = 0;
1018 addr = (caddr_t)&td->td_mailbox->tm_sticks;
1019 if (suword32(addr, uticks+fuword32(addr)))
1020 goto error;
1021 }
1022 return (0);
1023
1024 error:
1025 PROC_LOCK(p);
1026 psignal(p, SIGSEGV);
1027 PROC_UNLOCK(p);
1028 return (-2);
1029 }
1030
1031 /*
1032 * This function is intended to be used to initialize a spare thread
1033 * for upcall. Initialize thread's large data area outside sched_lock
1034 * for thread_schedule_upcall(). The crhold is also here to get it out
1035 * from the schedlock as it has a mutex op itself.
1036 * XXX BUG.. we need to get the cr ref after the thread has
1037 * checked and chenged its own, not 6 months before...
1038 */
1039 void
1040 thread_alloc_spare(struct thread *td)
1041 {
1042 struct thread *spare;
1043
1044 if (td->td_standin)
1045 return;
1046 spare = thread_alloc();
1047 td->td_standin = spare;
1048 bzero(&spare->td_startzero,
1049 __rangeof(struct thread, td_startzero, td_endzero));
1050 spare->td_proc = td->td_proc;
1051 spare->td_ucred = crhold(td->td_ucred);
1052 }
1053
1054 /*
1055 * Create a thread and schedule it for upcall on the KSE given.
1056 * Use our thread's standin so that we don't have to allocate one.
1057 */
1058 struct thread *
1059 thread_schedule_upcall(struct thread *td, struct kse_upcall *ku)
1060 {
1061 struct thread *td2;
1062
1063 mtx_assert(&sched_lock, MA_OWNED);
1064
1065 /*
1066 * Schedule an upcall thread on specified kse_upcall,
1067 * the kse_upcall must be free.
1068 * td must have a spare thread.
1069 */
1070 KASSERT(ku->ku_owner == NULL, ("%s: upcall has owner", __func__));
1071 if ((td2 = td->td_standin) != NULL) {
1072 td->td_standin = NULL;
1073 } else {
1074 panic("no reserve thread when scheduling an upcall");
1075 return (NULL);
1076 }
1077 CTR3(KTR_PROC, "thread_schedule_upcall: thread %p (pid %d, %s)",
1078 td2, td->td_proc->p_pid, td->td_proc->p_comm);
1079 /*
1080 * Bzero already done in thread_alloc_spare() because we can't
1081 * do the crhold here because we are in schedlock already.
1082 */
1083 bcopy(&td->td_startcopy, &td2->td_startcopy,
1084 __rangeof(struct thread, td_startcopy, td_endcopy));
1085 thread_link(td2, ku->ku_ksegrp);
1086 /* inherit parts of blocked thread's context as a good template */
1087 cpu_set_upcall(td2, td);
1088 /* Let the new thread become owner of the upcall */
1089 ku->ku_owner = td2;
1090 td2->td_upcall = ku;
1091 td2->td_flags = 0;
1092 td2->td_pflags = TDP_SA|TDP_UPCALLING;
1093 td2->td_state = TDS_CAN_RUN;
1094 td2->td_inhibitors = 0;
1095 SIGFILLSET(td2->td_sigmask);
1096 SIG_CANTMASK(td2->td_sigmask);
1097 sched_fork_thread(td, td2);
1098 return (td2); /* bogus.. should be a void function */
1099 }
1100
1101 /*
1102 * It is only used when thread generated a trap and process is being
1103 * debugged.
1104 */
1105 void
1106 thread_signal_add(struct thread *td, int sig)
1107 {
1108 struct proc *p;
1109 siginfo_t siginfo;
1110 struct sigacts *ps;
1111 int error;
1112
1113 p = td->td_proc;
1114 PROC_LOCK_ASSERT(p, MA_OWNED);
1115 ps = p->p_sigacts;
1116 mtx_assert(&ps->ps_mtx, MA_OWNED);
1117
1118 cpu_thread_siginfo(sig, 0, &siginfo);
1119 mtx_unlock(&ps->ps_mtx);
1120 SIGADDSET(td->td_sigmask, sig);
1121 PROC_UNLOCK(p);
1122 error = copyout(&siginfo, &td->td_mailbox->tm_syncsig, sizeof(siginfo));
1123 if (error) {
1124 PROC_LOCK(p);
1125 sigexit(td, SIGSEGV);
1126 }
1127 PROC_LOCK(p);
1128 mtx_lock(&ps->ps_mtx);
1129 }
1130 #include "opt_sched.h"
1131 struct thread *
1132 thread_switchout(struct thread *td, int flags, struct thread *nextthread)
1133 {
1134 struct kse_upcall *ku;
1135 struct thread *td2;
1136
1137 mtx_assert(&sched_lock, MA_OWNED);
1138
1139 /*
1140 * If the outgoing thread is in threaded group and has never
1141 * scheduled an upcall, decide whether this is a short
1142 * or long term event and thus whether or not to schedule
1143 * an upcall.
1144 * If it is a short term event, just suspend it in
1145 * a way that takes its KSE with it.
1146 * Select the events for which we want to schedule upcalls.
1147 * For now it's just sleep or if thread is suspended but
1148 * process wide suspending flag is not set (debugger
1149 * suspends thread).
1150 * XXXKSE eventually almost any inhibition could do.
1151 */
1152 if (TD_CAN_UNBIND(td) && (td->td_standin) &&
1153 (TD_ON_SLEEPQ(td) || (TD_IS_SUSPENDED(td) &&
1154 !P_SHOULDSTOP(td->td_proc)))) {
1155 /*
1156 * Release ownership of upcall, and schedule an upcall
1157 * thread, this new upcall thread becomes the owner of
1158 * the upcall structure. It will be ahead of us in the
1159 * run queue, so as we are stopping, it should either
1160 * start up immediatly, or at least before us if
1161 * we release our slot.
1162 */
1163 ku = td->td_upcall;
1164 ku->ku_owner = NULL;
1165 td->td_upcall = NULL;
1166 td->td_pflags &= ~TDP_CAN_UNBIND;
1167 td2 = thread_schedule_upcall(td, ku);
1168 if (flags & SW_INVOL || nextthread) {
1169 setrunqueue(td2, SRQ_YIELDING);
1170 } else {
1171 /* Keep up with reality.. we have one extra thread
1172 * in the picture.. and it's 'running'.
1173 */
1174 return td2;
1175 }
1176 }
1177 return (nextthread);
1178 }
1179
1180 /*
1181 * Setup done on the thread when it enters the kernel.
1182 */
1183 void
1184 thread_user_enter(struct thread *td)
1185 {
1186 struct proc *p = td->td_proc;
1187 struct ksegrp *kg;
1188 struct kse_upcall *ku;
1189 struct kse_thr_mailbox *tmbx;
1190 uint32_t flags;
1191
1192 /*
1193 * First check that we shouldn't just abort. we
1194 * can suspend it here or just exit.
1195 */
1196 if (__predict_false(P_SHOULDSTOP(p))) {
1197 PROC_LOCK(p);
1198 thread_suspend_check(0);
1199 PROC_UNLOCK(p);
1200 }
1201
1202 if (!(td->td_pflags & TDP_SA))
1203 return;
1204
1205 /*
1206 * If we are doing a syscall in a KSE environment,
1207 * note where our mailbox is.
1208 */
1209
1210 kg = td->td_ksegrp;
1211 ku = td->td_upcall;
1212
1213 KASSERT(ku != NULL, ("no upcall owned"));
1214 KASSERT(ku->ku_owner == td, ("wrong owner"));
1215 KASSERT(!TD_CAN_UNBIND(td), ("can unbind"));
1216
1217 if (td->td_standin == NULL)
1218 thread_alloc_spare(td);
1219 ku->ku_mflags = fuword32((void *)&ku->ku_mailbox->km_flags);
1220 tmbx = (void *)fuword((void *)&ku->ku_mailbox->km_curthread);
1221 if ((tmbx == NULL) || (tmbx == (void *)-1L) ||
1222 (ku->ku_mflags & KMF_NOUPCALL)) {
1223 td->td_mailbox = NULL;
1224 } else {
1225 flags = fuword32(&tmbx->tm_flags);
1226 /*
1227 * On some architectures, TP register points to thread
1228 * mailbox but not points to kse mailbox, and userland
1229 * can not atomically clear km_curthread, but can
1230 * use TP register, and set TMF_NOUPCALL in thread
1231 * flag to indicate a critical region.
1232 */
1233 if (flags & TMF_NOUPCALL) {
1234 td->td_mailbox = NULL;
1235 } else {
1236 td->td_mailbox = tmbx;
1237 td->td_pflags |= TDP_CAN_UNBIND;
1238 if (__predict_false(p->p_flag & P_TRACED)) {
1239 flags = fuword32(&tmbx->tm_dflags);
1240 if (flags & TMDF_SUSPEND) {
1241 mtx_lock_spin(&sched_lock);
1242 /* fuword can block, check again */
1243 if (td->td_upcall)
1244 ku->ku_flags |= KUF_DOUPCALL;
1245 mtx_unlock_spin(&sched_lock);
1246 }
1247 }
1248 }
1249 }
1250 }
1251
1252 /*
1253 * The extra work we go through if we are a threaded process when we
1254 * return to userland.
1255 *
1256 * If we are a KSE process and returning to user mode, check for
1257 * extra work to do before we return (e.g. for more syscalls
1258 * to complete first). If we were in a critical section, we should
1259 * just return to let it finish. Same if we were in the UTS (in
1260 * which case the mailbox's context's busy indicator will be set).
1261 * The only traps we suport will have set the mailbox.
1262 * We will clear it here.
1263 */
1264 int
1265 thread_userret(struct thread *td, struct trapframe *frame)
1266 {
1267 struct kse_upcall *ku;
1268 struct ksegrp *kg, *kg2;
1269 struct proc *p;
1270 struct timespec ts;
1271 int error = 0, upcalls, uts_crit;
1272
1273 /* Nothing to do with bound thread */
1274 if (!(td->td_pflags & TDP_SA))
1275 return (0);
1276
1277 /*
1278 * Update stat clock count for userland
1279 */
1280 if (td->td_mailbox != NULL) {
1281 thread_update_usr_ticks(td);
1282 uts_crit = 0;
1283 } else {
1284 uts_crit = 1;
1285 }
1286
1287 p = td->td_proc;
1288 kg = td->td_ksegrp;
1289 ku = td->td_upcall;
1290
1291 /*
1292 * Optimisation:
1293 * This thread has not started any upcall.
1294 * If there is no work to report other than ourself,
1295 * then it can return direct to userland.
1296 */
1297 if (TD_CAN_UNBIND(td)) {
1298 td->td_pflags &= ~TDP_CAN_UNBIND;
1299 if ((td->td_flags & TDF_NEEDSIGCHK) == 0 &&
1300 (kg->kg_completed == NULL) &&
1301 (ku->ku_flags & KUF_DOUPCALL) == 0 &&
1302 (kg->kg_upquantum && ticks < kg->kg_nextupcall)) {
1303 nanotime(&ts);
1304 error = copyout(&ts,
1305 (caddr_t)&ku->ku_mailbox->km_timeofday,
1306 sizeof(ts));
1307 td->td_mailbox = 0;
1308 ku->ku_mflags = 0;
1309 if (error)
1310 goto out;
1311 return (0);
1312 }
1313 thread_export_context(td, 0);
1314 /*
1315 * There is something to report, and we own an upcall
1316 * structure, we can go to userland.
1317 * Turn ourself into an upcall thread.
1318 */
1319 td->td_pflags |= TDP_UPCALLING;
1320 } else if (td->td_mailbox && (ku == NULL)) {
1321 thread_export_context(td, 1);
1322 PROC_LOCK(p);
1323 if (kg->kg_upsleeps)
1324 wakeup(&kg->kg_completed);
1325 WITNESS_WARN(WARN_PANIC, &p->p_mtx.mtx_object,
1326 "thread exiting in userret");
1327 mtx_lock_spin(&sched_lock);
1328 thread_stopped(p);
1329 thread_exit();
1330 /* NOTREACHED */
1331 }
1332
1333 KASSERT(ku != NULL, ("upcall is NULL"));
1334 KASSERT(TD_CAN_UNBIND(td) == 0, ("can unbind"));
1335
1336 if (p->p_numthreads > max_threads_per_proc) {
1337 max_threads_hits++;
1338 PROC_LOCK(p);
1339 mtx_lock_spin(&sched_lock);
1340 p->p_maxthrwaits++;
1341 while (p->p_numthreads > max_threads_per_proc) {
1342 upcalls = 0;
1343 FOREACH_KSEGRP_IN_PROC(p, kg2) {
1344 if (kg2->kg_numupcalls == 0)
1345 upcalls++;
1346 else
1347 upcalls += kg2->kg_numupcalls;
1348 }
1349 if (upcalls >= max_threads_per_proc)
1350 break;
1351 mtx_unlock_spin(&sched_lock);
1352 if (msleep(&p->p_numthreads, &p->p_mtx, PPAUSE|PCATCH,
1353 "maxthreads", hz/10) != EWOULDBLOCK) {
1354 mtx_lock_spin(&sched_lock);
1355 break;
1356 } else {
1357 mtx_lock_spin(&sched_lock);
1358 }
1359 }
1360 p->p_maxthrwaits--;
1361 mtx_unlock_spin(&sched_lock);
1362 PROC_UNLOCK(p);
1363 }
1364
1365 if (td->td_pflags & TDP_UPCALLING) {
1366 uts_crit = 0;
1367 kg->kg_nextupcall = ticks + kg->kg_upquantum;
1368 /*
1369 * There is no more work to do and we are going to ride
1370 * this thread up to userland as an upcall.
1371 * Do the last parts of the setup needed for the upcall.
1372 */
1373 CTR3(KTR_PROC, "userret: upcall thread %p (pid %d, %s)",
1374 td, td->td_proc->p_pid, td->td_proc->p_comm);
1375
1376 td->td_pflags &= ~TDP_UPCALLING;
1377 if (ku->ku_flags & KUF_DOUPCALL) {
1378 mtx_lock_spin(&sched_lock);
1379 ku->ku_flags &= ~KUF_DOUPCALL;
1380 mtx_unlock_spin(&sched_lock);
1381 }
1382 /*
1383 * Set user context to the UTS
1384 */
1385 if (!(ku->ku_mflags & KMF_NOUPCALL)) {
1386 cpu_set_upcall_kse(td, ku->ku_func, ku->ku_mailbox,
1387 &ku->ku_stack);
1388 PROC_LOCK(p);
1389 if (p->p_flag & P_TRACED) {
1390 _PHOLD(p);
1391 ptrace_clear_single_step(td);
1392 _PRELE(p);
1393 }
1394 PROC_UNLOCK(p);
1395 error = suword32(&ku->ku_mailbox->km_lwp,
1396 td->td_tid);
1397 if (error)
1398 goto out;
1399 error = suword(&ku->ku_mailbox->km_curthread, 0);
1400 if (error)
1401 goto out;
1402 }
1403
1404 /*
1405 * Unhook the list of completed threads.
1406 * anything that completes after this gets to
1407 * come in next time.
1408 * Put the list of completed thread mailboxes on
1409 * this KSE's mailbox.
1410 */
1411 if (!(ku->ku_mflags & KMF_NOCOMPLETED) &&
1412 (error = thread_link_mboxes(kg, ku)) != 0)
1413 goto out;
1414 }
1415 if (!uts_crit) {
1416 nanotime(&ts);
1417 error = copyout(&ts, &ku->ku_mailbox->km_timeofday, sizeof(ts));
1418 }
1419
1420 out:
1421 if (error) {
1422 /*
1423 * Things are going to be so screwed we should just kill
1424 * the process.
1425 * how do we do that?
1426 */
1427 PROC_LOCK(p);
1428 psignal(p, SIGSEGV);
1429 PROC_UNLOCK(p);
1430 } else {
1431 /*
1432 * Optimisation:
1433 * Ensure that we have a spare thread available,
1434 * for when we re-enter the kernel.
1435 */
1436 if (td->td_standin == NULL)
1437 thread_alloc_spare(td);
1438 }
1439
1440 ku->ku_mflags = 0;
1441 td->td_mailbox = NULL;
1442 td->td_usticks = 0;
1443 return (error); /* go sync */
1444 }
1445
1446 /*
1447 * called after ptrace resumed a process, force all
1448 * virtual CPUs to schedule upcall for SA process,
1449 * because debugger may have changed something in userland,
1450 * we should notice UTS as soon as possible.
1451 */
1452 void
1453 thread_continued(struct proc *p)
1454 {
1455 struct ksegrp *kg;
1456 struct kse_upcall *ku;
1457 struct thread *td;
1458
1459 PROC_LOCK_ASSERT(p, MA_OWNED);
1460 KASSERT(P_SHOULDSTOP(p), ("process not stopped"));
1461
1462 if (!(p->p_flag & P_SA))
1463 return;
1464
1465 if (p->p_flag & P_TRACED) {
1466 FOREACH_KSEGRP_IN_PROC(p, kg) {
1467 td = TAILQ_FIRST(&kg->kg_threads);
1468 if (td == NULL)
1469 continue;
1470 /* not a SA group, nothing to do */
1471 if (!(td->td_pflags & TDP_SA))
1472 continue;
1473 FOREACH_UPCALL_IN_GROUP(kg, ku) {
1474 mtx_lock_spin(&sched_lock);
1475 ku->ku_flags |= KUF_DOUPCALL;
1476 mtx_unlock_spin(&sched_lock);
1477 wakeup(&kg->kg_completed);
1478 }
1479 }
1480 }
1481 }
Cache object: a2fe74e3778bd0f446f3e491bf4cbfca
|