1 /*-
2 * Copyright (c) 2003, Jeffrey Roberson <jeff@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 unmodified, this list of conditions, and the following
10 * disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29
30 #include "opt_compat.h"
31 #include "opt_posix.h"
32 #include "opt_thrworkq.h"
33
34 #include <sys/param.h>
35 #include <sys/kernel.h>
36 #include <sys/lock.h>
37 #include <sys/mman.h>
38 #include <sys/mutex.h>
39 #include <sys/priv.h>
40 #include <sys/proc.h>
41 #include <sys/posix4.h>
42 #include <sys/racct.h>
43 #include <sys/resourcevar.h>
44 #include <sys/rwlock.h>
45 #include <sys/sched.h>
46 #include <sys/sysctl.h>
47 #include <sys/smp.h>
48 #include <sys/syscallsubr.h>
49 #include <sys/sysent.h>
50 #include <sys/systm.h>
51 #include <sys/sysproto.h>
52 #include <sys/signalvar.h>
53 #include <sys/sysctl.h>
54 #include <sys/ucontext.h>
55 #include <sys/thr.h>
56 #include <sys/rtprio.h>
57 #include <sys/thrworkq.h>
58 #include <sys/umtx.h>
59 #include <sys/limits.h>
60
61 #include <vm/vm_domain.h>
62
63 #include <machine/frame.h>
64
65 #include <vm/pmap.h>
66 #include <vm/vm.h>
67 #include <vm/vm_extern.h>
68 #include <vm/vm_map.h>
69
70 #include <security/audit/audit.h>
71
72 /*
73 * Default stack guard size for thread. If set to zero then no
74 * guard page.
75 */
76 #define THR_GUARD_DEFAULT PAGE_SIZE
77
78 /*
79 * XXX - These should most likely be sysctl parameters.
80 */
81 static vm_size_t thr_stack_default = THR_STACK_DEFAULT;
82 static vm_size_t thr_stack_initial = THR_STACK_INITIAL;
83
84 static SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0,
85 "thread allocation");
86
87 static int max_threads_per_proc = 1500;
88 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
89 &max_threads_per_proc, 0, "Limit on threads per proc");
90
91 static int max_threads_hits;
92 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
93 &max_threads_hits, 0, "kern.threads.max_threads_per_proc hit count");
94
95 #ifdef COMPAT_FREEBSD32
96
97 static inline int
suword_lwpid(void * addr,lwpid_t lwpid)98 suword_lwpid(void *addr, lwpid_t lwpid)
99 {
100 int error;
101
102 if (SV_CURPROC_FLAG(SV_LP64))
103 error = suword(addr, lwpid);
104 else
105 error = suword32(addr, lwpid);
106 return (error);
107 }
108
109 #else
110 #define suword_lwpid suword
111 #endif
112
113 /*
114 * System call interface.
115 */
116
117 struct thr_create_initthr_args {
118 ucontext_t ctx;
119 long *tid;
120 };
121
122 static int
thr_create_initthr(struct thread * td,void * thunk)123 thr_create_initthr(struct thread *td, void *thunk)
124 {
125 struct thr_create_initthr_args *args;
126
127 /* Copy out the child tid. */
128 args = thunk;
129 if (args->tid != NULL && suword_lwpid(args->tid, td->td_tid))
130 return (EFAULT);
131
132 return (set_mcontext(td, &args->ctx.uc_mcontext));
133 }
134
135 int
sys_thr_create(struct thread * td,struct thr_create_args * uap)136 sys_thr_create(struct thread *td, struct thr_create_args *uap)
137 /* ucontext_t *ctx, long *id, int flags */
138 {
139 struct thr_create_initthr_args args;
140 int error;
141
142 if ((error = copyin(uap->ctx, &args.ctx, sizeof(args.ctx))))
143 return (error);
144 args.tid = uap->id;
145 return (thread_create(td, NULL, thr_create_initthr, &args));
146 }
147
148 int
sys_thr_new(struct thread * td,struct thr_new_args * uap)149 sys_thr_new(struct thread *td, struct thr_new_args *uap)
150 /* struct thr_param * */
151 {
152 struct thr_param param;
153 int error;
154
155 if (uap->param_size < 0 || uap->param_size > sizeof(param))
156 return (EINVAL);
157 bzero(¶m, sizeof(param));
158 if ((error = copyin(uap->param, ¶m, uap->param_size)))
159 return (error);
160 return (kern_thr_new(td, ¶m));
161 }
162
163 static int
thr_new_initthr(struct thread * td,void * thunk)164 thr_new_initthr(struct thread *td, void *thunk)
165 {
166 stack_t stack;
167 struct thr_param *param;
168
169 /*
170 * Here we copy out tid to two places, one for child and one
171 * for parent, because pthread can create a detached thread,
172 * if parent wants to safely access child tid, it has to provide
173 * its storage, because child thread may exit quickly and
174 * memory is freed before parent thread can access it.
175 */
176 param = thunk;
177 if ((param->child_tid != NULL &&
178 suword_lwpid(param->child_tid, td->td_tid)) ||
179 (param->parent_tid != NULL &&
180 suword_lwpid(param->parent_tid, td->td_tid)))
181 return (EFAULT);
182
183 /* Set up our machine context. */
184 stack.ss_sp = param->stack_base;
185 stack.ss_size = param->stack_size;
186 /* Set upcall address to user thread entry function. */
187 cpu_set_upcall_kse(td, param->start_func, param->arg, &stack);
188 /* Setup user TLS address and TLS pointer register. */
189 return (cpu_set_user_tls(td, param->tls_base));
190 }
191
192 int
kern_thr_new(struct thread * td,struct thr_param * param)193 kern_thr_new(struct thread *td, struct thr_param *param)
194 {
195 struct rtprio rtp, *rtpp;
196 int error;
197
198 rtpp = NULL;
199 if (param->rtp != 0) {
200 error = copyin(param->rtp, &rtp, sizeof(struct rtprio));
201 if (error)
202 return (error);
203 rtpp = &rtp;
204 }
205 return (thread_create(td, rtpp, thr_new_initthr, param));
206 }
207
208 int
thread_create(struct thread * td,struct rtprio * rtp,int (* initialize_thread)(struct thread *,void *),void * thunk)209 thread_create(struct thread *td, struct rtprio *rtp,
210 int (*initialize_thread)(struct thread *, void *), void *thunk)
211 {
212 struct thread *newtd;
213 struct proc *p;
214 int error;
215
216 p = td->td_proc;
217
218 if (rtp != NULL) {
219 switch(rtp->type) {
220 case RTP_PRIO_REALTIME:
221 case RTP_PRIO_FIFO:
222 /* Only root can set scheduler policy */
223 if (priv_check(td, PRIV_SCHED_SETPOLICY) != 0)
224 return (EPERM);
225 if (rtp->prio > RTP_PRIO_MAX)
226 return (EINVAL);
227 break;
228 case RTP_PRIO_NORMAL:
229 rtp->prio = 0;
230 break;
231 default:
232 return (EINVAL);
233 }
234 }
235
236 #ifdef RACCT
237 if (racct_enable) {
238 PROC_LOCK(p);
239 error = racct_add(p, RACCT_NTHR, 1);
240 PROC_UNLOCK(p);
241 if (error != 0)
242 return (EPROCLIM);
243 }
244 #endif
245
246 /* Initialize our td */
247 error = kern_thr_alloc(p, 0, &newtd);
248 if (error)
249 goto fail;
250
251 cpu_set_upcall(newtd, td);
252
253 bzero(&newtd->td_startzero,
254 __rangeof(struct thread, td_startzero, td_endzero));
255 bcopy(&td->td_startcopy, &newtd->td_startcopy,
256 __rangeof(struct thread, td_startcopy, td_endcopy));
257 newtd->td_proc = td->td_proc;
258 thread_cow_get(newtd, td);
259
260 error = initialize_thread(newtd, thunk);
261 if (error != 0) {
262 thread_cow_free(newtd);
263 thread_free(newtd);
264 goto fail;
265 }
266
267 PROC_LOCK(p);
268 p->p_flag |= P_HADTHREADS;
269 thread_link(newtd, p);
270 bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
271 thread_lock(td);
272 /* let the scheduler know about these things. */
273 sched_fork_thread(td, newtd);
274 thread_unlock(td);
275 if (P_SHOULDSTOP(p))
276 newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
277 if (p->p_flag2 & P2_LWP_EVENTS)
278 newtd->td_dbgflags |= TDB_BORN;
279
280 /*
281 * Copy the existing thread VM policy into the new thread.
282 */
283 vm_domain_policy_localcopy(&newtd->td_vm_dom_policy,
284 &td->td_vm_dom_policy);
285
286 PROC_UNLOCK(p);
287
288 tidhash_add(newtd);
289
290 thread_lock(newtd);
291 if (rtp != NULL) {
292 if (!(td->td_pri_class == PRI_TIMESHARE &&
293 rtp->type == RTP_PRIO_NORMAL)) {
294 rtp_to_pri(rtp, newtd);
295 sched_prio(newtd, newtd->td_user_pri);
296 } /* ignore timesharing class */
297 }
298 TD_SET_CAN_RUN(newtd);
299 sched_add(newtd, SRQ_BORING);
300 thread_unlock(newtd);
301
302 return (0);
303
304 fail:
305 #ifdef RACCT
306 if (racct_enable) {
307 PROC_LOCK(p);
308 racct_sub(p, RACCT_NTHR, 1);
309 PROC_UNLOCK(p);
310 }
311 #endif
312 return (error);
313 }
314
315 int
sys_thr_self(struct thread * td,struct thr_self_args * uap)316 sys_thr_self(struct thread *td, struct thr_self_args *uap)
317 /* long *id */
318 {
319 int error;
320
321 error = suword_lwpid(uap->id, (unsigned)td->td_tid);
322 if (error == -1)
323 return (EFAULT);
324 return (0);
325 }
326
327 int
sys_thr_exit(struct thread * td,struct thr_exit_args * uap)328 sys_thr_exit(struct thread *td, struct thr_exit_args *uap)
329 /* long *state */
330 {
331
332 #ifdef THRWORKQ
333 if (td->td_reuse_stack != NULL) {
334 thrworkq_reusestack(td->td_proc, td->td_reuse_stack);
335 td->td_reuse_stack = NULL;
336 }
337 #endif
338
339 if ((void *)uap->state != NULL) {
340 /* Signal userland that it can free the stack. */
341 suword_lwpid(uap->state, 1);
342 kern_umtx_wake(td, uap->state, INT_MAX, 0);
343 }
344
345 return (kern_thr_exit(td));
346 }
347
348 int
kern_thr_exit(struct thread * td)349 kern_thr_exit(struct thread *td)
350 {
351 struct proc *p;
352
353 p = td->td_proc;
354
355 /*
356 * If all of the threads in a process call this routine to
357 * exit (e.g. all threads call pthread_exit()), exactly one
358 * thread should return to the caller to terminate the process
359 * instead of the thread.
360 *
361 * Checking p_numthreads alone is not sufficient since threads
362 * might be committed to terminating while the PROC_LOCK is
363 * dropped in either ptracestop() or while removing this thread
364 * from the tidhash. Instead, the p_pendingexits field holds
365 * the count of threads in either of those states and a thread
366 * is considered the "last" thread if all of the other threads
367 * in a process are already terminating.
368 */
369 PROC_LOCK(p);
370 if (p->p_numthreads == p->p_pendingexits + 1) {
371 /*
372 * Ignore attempts to shut down last thread in the
373 * proc. This will actually call _exit(2) in the
374 * usermode trampoline when it returns.
375 */
376 PROC_UNLOCK(p);
377 return (0);
378 }
379
380 p->p_pendingexits++;
381 td->td_dbgflags |= TDB_EXIT;
382 if (p->p_flag & P_TRACED && p->p_flag2 & P2_LWP_EVENTS)
383 ptracestop(td, SIGTRAP);
384 PROC_UNLOCK(p);
385 tidhash_remove(td);
386 PROC_LOCK(p);
387 p->p_pendingexits--;
388
389 /*
390 * The check above should prevent all other threads from this
391 * process from exiting while the PROC_LOCK is dropped, so
392 * there must be at least one other thread other than the
393 * current thread.
394 */
395 KASSERT(p->p_numthreads > 1, ("too few threads"));
396 racct_sub(p, RACCT_NTHR, 1);
397 tdsigcleanup(td);
398 umtx_thread_exit(td);
399 PROC_SLOCK(p);
400 thread_stopped(p);
401 thread_exit();
402 /* NOTREACHED */
403 }
404
405 int
sys_thr_kill(struct thread * td,struct thr_kill_args * uap)406 sys_thr_kill(struct thread *td, struct thr_kill_args *uap)
407 /* long id, int sig */
408 {
409 ksiginfo_t ksi;
410 struct thread *ttd;
411 struct proc *p;
412 int error;
413
414 p = td->td_proc;
415 ksiginfo_init(&ksi);
416 ksi.ksi_signo = uap->sig;
417 ksi.ksi_code = SI_LWP;
418 ksi.ksi_pid = p->p_pid;
419 ksi.ksi_uid = td->td_ucred->cr_ruid;
420 if (uap->id == -1) {
421 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
422 error = EINVAL;
423 } else {
424 error = ESRCH;
425 PROC_LOCK(p);
426 FOREACH_THREAD_IN_PROC(p, ttd) {
427 if (ttd != td) {
428 error = 0;
429 if (uap->sig == 0)
430 break;
431 tdksignal(ttd, uap->sig, &ksi);
432 }
433 }
434 PROC_UNLOCK(p);
435 }
436 } else {
437 error = 0;
438 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
439 if (ttd == NULL)
440 return (ESRCH);
441 if (uap->sig == 0)
442 ;
443 else if (!_SIG_VALID(uap->sig))
444 error = EINVAL;
445 else
446 tdksignal(ttd, uap->sig, &ksi);
447 PROC_UNLOCK(ttd->td_proc);
448 }
449 return (error);
450 }
451
452 int
sys_thr_kill2(struct thread * td,struct thr_kill2_args * uap)453 sys_thr_kill2(struct thread *td, struct thr_kill2_args *uap)
454 /* pid_t pid, long id, int sig */
455 {
456 ksiginfo_t ksi;
457 struct thread *ttd;
458 struct proc *p;
459 int error;
460
461 AUDIT_ARG_SIGNUM(uap->sig);
462
463 ksiginfo_init(&ksi);
464 ksi.ksi_signo = uap->sig;
465 ksi.ksi_code = SI_LWP;
466 ksi.ksi_pid = td->td_proc->p_pid;
467 ksi.ksi_uid = td->td_ucred->cr_ruid;
468 if (uap->id == -1) {
469 if ((p = pfind(uap->pid)) == NULL)
470 return (ESRCH);
471 AUDIT_ARG_PROCESS(p);
472 error = p_cansignal(td, p, uap->sig);
473 if (error) {
474 PROC_UNLOCK(p);
475 return (error);
476 }
477 if (uap->sig != 0 && !_SIG_VALID(uap->sig)) {
478 error = EINVAL;
479 } else {
480 error = ESRCH;
481 FOREACH_THREAD_IN_PROC(p, ttd) {
482 if (ttd != td) {
483 error = 0;
484 if (uap->sig == 0)
485 break;
486 tdksignal(ttd, uap->sig, &ksi);
487 }
488 }
489 }
490 PROC_UNLOCK(p);
491 } else {
492 ttd = tdfind((lwpid_t)uap->id, uap->pid);
493 if (ttd == NULL)
494 return (ESRCH);
495 p = ttd->td_proc;
496 AUDIT_ARG_PROCESS(p);
497 error = p_cansignal(td, p, uap->sig);
498 if (uap->sig == 0)
499 ;
500 else if (!_SIG_VALID(uap->sig))
501 error = EINVAL;
502 else
503 tdksignal(ttd, uap->sig, &ksi);
504 PROC_UNLOCK(p);
505 }
506 return (error);
507 }
508
509 int
sys_thr_suspend(struct thread * td,struct thr_suspend_args * uap)510 sys_thr_suspend(struct thread *td, struct thr_suspend_args *uap)
511 /* const struct timespec *timeout */
512 {
513 struct timespec ts, *tsp;
514 int error;
515
516 tsp = NULL;
517 if (uap->timeout != NULL) {
518 error = umtx_copyin_timeout(uap->timeout, &ts);
519 if (error != 0)
520 return (error);
521 tsp = &ts;
522 }
523
524 return (kern_thr_suspend(td, tsp));
525 }
526
527 int
kern_thr_suspend(struct thread * td,struct timespec * tsp)528 kern_thr_suspend(struct thread *td, struct timespec *tsp)
529 {
530 struct proc *p = td->td_proc;
531 struct timeval tv;
532 int error = 0;
533 int timo = 0;
534
535 if (td->td_pflags & TDP_WAKEUP) {
536 td->td_pflags &= ~TDP_WAKEUP;
537 return (0);
538 }
539
540 if (tsp != NULL) {
541 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0)
542 error = EWOULDBLOCK;
543 else {
544 TIMESPEC_TO_TIMEVAL(&tv, tsp);
545 timo = tvtohz(&tv);
546 }
547 }
548
549 PROC_LOCK(p);
550 if (error == 0 && (td->td_flags & TDF_THRWAKEUP) == 0)
551 error = msleep((void *)td, &p->p_mtx,
552 PCATCH, "lthr", timo);
553
554 if (td->td_flags & TDF_THRWAKEUP) {
555 thread_lock(td);
556 td->td_flags &= ~TDF_THRWAKEUP;
557 thread_unlock(td);
558 PROC_UNLOCK(p);
559 return (0);
560 }
561 PROC_UNLOCK(p);
562 if (error == EWOULDBLOCK)
563 error = ETIMEDOUT;
564 else if (error == ERESTART) {
565 if (timo != 0)
566 error = EINTR;
567 }
568 return (error);
569 }
570
571 int
sys_thr_wake(struct thread * td,struct thr_wake_args * uap)572 sys_thr_wake(struct thread *td, struct thr_wake_args *uap)
573 /* long id */
574 {
575 struct proc *p;
576 struct thread *ttd;
577
578 if (uap->id == td->td_tid) {
579 td->td_pflags |= TDP_WAKEUP;
580 return (0);
581 }
582
583 p = td->td_proc;
584 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
585 if (ttd == NULL)
586 return (ESRCH);
587 thread_lock(ttd);
588 ttd->td_flags |= TDF_THRWAKEUP;
589 thread_unlock(ttd);
590 wakeup((void *)ttd);
591 PROC_UNLOCK(p);
592 return (0);
593 }
594
595 int
sys_thr_set_name(struct thread * td,struct thr_set_name_args * uap)596 sys_thr_set_name(struct thread *td, struct thr_set_name_args *uap)
597 {
598 struct proc *p;
599 char name[MAXCOMLEN + 1];
600 struct thread *ttd;
601 int error;
602
603 error = 0;
604 name[0] = '\0';
605 if (uap->name != NULL) {
606 error = copyinstr(uap->name, name, sizeof(name),
607 NULL);
608 if (error)
609 return (error);
610 }
611 p = td->td_proc;
612 ttd = tdfind((lwpid_t)uap->id, p->p_pid);
613 if (ttd == NULL)
614 return (ESRCH);
615 strcpy(ttd->td_name, name);
616 #ifdef KTR
617 sched_clear_tdname(ttd);
618 #endif
619 PROC_UNLOCK(p);
620 return (error);
621 }
622
623 int
sys_thr_stack(struct thread * td,struct thr_stack_args * uap)624 sys_thr_stack(struct thread *td, struct thr_stack_args *uap)
625 {
626 vm_size_t stacksz, guardsz;
627 void *addr;
628 int error;
629
630 /* Round up to the nearest page size. */
631 stacksz = (vm_size_t)round_page(uap->stacksize);
632 guardsz = (vm_size_t)round_page(uap->guardsize);
633
634 if (stacksz == 0)
635 stacksz = thr_stack_default;
636
637 error = kern_thr_stack(td->td_proc, &addr, stacksz, guardsz);
638
639 td->td_retval[0] = (register_t) addr;
640
641 return (error);
642 }
643
644 /*
645 * kern_thr_stack() maps a new thread stack in the process. It returns
646 * the stack address in the 'addr' arg.
647 *
648 * Base address of the last stack allocated (including its red zone, if
649 * there is one). Stacks are allocated contiguously, starting beyond the
650 * top of the main stack. When a new stack is created, a red zone is
651 * typically created (actually, the red zone is mapped with PROT_NONE) above
652 * the top of the stack, such that the stack will not be able to grow all
653 * the way to the bottom of the next stack. This isn't fool-proof. It is
654 * possible for a stack to grow by a large amount, such that it grows into
655 * the next stack, and as long as the memory within the red zone is never
656 * accessed, nothing will prevent one thread stack from trouncing all over
657 * the next.
658 *
659 * low memory
660 * . . . . . . . . . . . . . . . . . .
661 * | |
662 * | stack 3 | start of 3rd thread stack
663 * +-----------------------------------+
664 * | |
665 * | Red Zone (guard page) | red zone for 2nd thread
666 * | |
667 * +-----------------------------------+
668 * | stack 2 - thr_stack_default | top of 2nd thread stack
669 * | |
670 * | |
671 * | |
672 * | |
673 * | stack 2 |
674 * +-----------------------------------+ <-- start of 2nd thread stack
675 * | |
676 * | Red Zone (guard page) | red zone for 1st thread
677 * | |
678 * +-----------------------------------+
679 * | stack 1 - thr_stack_default | top of 1st thread stack
680 * | |
681 * | |
682 * | |
683 * | |
684 * | stack 1 |
685 * +-----------------------------------+ <-- start of 1st thread stack
686 * | | (initial value of p->p_thrstack)
687 * | Red Zone (guard page) |
688 * | | red zone for main thread
689 * +-----------------------------------+
690 * | ->sv_usrstack - thr_stack_initial | top of main thread stack
691 * | | ^
692 * | | |
693 * | | |
694 * | | | stack growth
695 * | |
696 * +-----------------------------------+ <-- start of main thread stack
697 * (p->p_sysent->sv_usrstack)
698 * high memory
699 *
700 * XXX - This code assumes that the stack always grows down in address space.
701 */
702 int
kern_thr_stack(struct proc * p,void ** addr,vm_size_t stacksz,vm_size_t guardsz)703 kern_thr_stack(struct proc *p, void **addr, vm_size_t stacksz,
704 vm_size_t guardsz)
705 {
706 vm_offset_t stackaddr;
707 vm_map_t map;
708 int error;
709
710 KASSERT(stacksz != 0, ("[%s: %d] stacksz = 0", __FILE__, __LINE__));
711
712 *addr = NULL;
713
714 PROC_LOCK(p);
715 if (p->p_thrstack == 0) {
716 /* Compute the start of the first thread stack. */
717 p->p_thrstack = p->p_sysent->sv_usrstack -
718 (vm_offset_t)(thr_stack_initial + THR_GUARD_DEFAULT);
719 }
720
721 stackaddr = p->p_thrstack - (vm_offset_t)(stacksz + guardsz);
722
723 /*
724 * Compute the next stack location unconditionally. Under normal
725 * operating conditions, the most likely reason for no being able
726 * to map the thread stack is a stack overflow of the adjacent
727 * thread stack.
728 */
729 p->p_thrstack -= (vm_offset_t)(stacksz + guardsz);
730 PROC_UNLOCK(p);
731
732 map = &p->p_vmspace->vm_map;
733 error = vm_mmap(map, &stackaddr, (stacksz + guardsz), VM_PROT_ALL,
734 PROT_READ | PROT_WRITE, MAP_STACK, OBJT_DEFAULT, NULL, 0);
735 if (error)
736 return (error);
737
738 if (guardsz != 0) {
739 error = vm_map_protect(map, stackaddr, stackaddr + guardsz,
740 PROT_NONE, 0);
741 if (error) {
742 /* unmap memory */
743 (void) vm_map_remove(map, stackaddr, stackaddr +
744 (stacksz + guardsz));
745
746 return (error);
747 }
748 }
749
750 *addr = (void *)(stackaddr + guardsz);
751 return (0);
752 }
753
754 int
kern_thr_alloc(struct proc * p,int pages,struct thread ** ntd)755 kern_thr_alloc(struct proc *p, int pages, struct thread **ntd)
756 {
757
758 /* Have race condition but it is cheap. */
759 if (p->p_numthreads >= max_threads_per_proc) {
760 ++max_threads_hits;
761 return (EPROCLIM);
762 }
763
764 *ntd = thread_alloc(pages);
765 if (*ntd == NULL)
766 return (ENOMEM);
767
768 return (0);
769 }
770