xref: /freebsd/sys/kern/kern_umtx.c (revision eb9da1ada8b6b2c74378a5c17029ec5a7fb199e6)
1 /*-
2  * Copyright (c) 2015, 2016 The FreeBSD Foundation
3  * Copyright (c) 2004, David Xu <davidxu@freebsd.org>
4  * Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
5  * All rights reserved.
6  *
7  * Portions of this software were developed by Konstantin Belousov
8  * under sponsorship from the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice unmodified, this list of conditions, and the following
15  *    disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
23  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_compat.h"
36 #include "opt_umtx_profiling.h"
37 
38 #include <sys/param.h>
39 #include <sys/kernel.h>
40 #include <sys/fcntl.h>
41 #include <sys/file.h>
42 #include <sys/filedesc.h>
43 #include <sys/limits.h>
44 #include <sys/lock.h>
45 #include <sys/malloc.h>
46 #include <sys/mman.h>
47 #include <sys/mutex.h>
48 #include <sys/priv.h>
49 #include <sys/proc.h>
50 #include <sys/resource.h>
51 #include <sys/resourcevar.h>
52 #include <sys/rwlock.h>
53 #include <sys/sbuf.h>
54 #include <sys/sched.h>
55 #include <sys/smp.h>
56 #include <sys/sysctl.h>
57 #include <sys/sysent.h>
58 #include <sys/systm.h>
59 #include <sys/sysproto.h>
60 #include <sys/syscallsubr.h>
61 #include <sys/taskqueue.h>
62 #include <sys/eventhandler.h>
63 #include <sys/umtx.h>
64 
65 #include <security/mac/mac_framework.h>
66 
67 #include <vm/vm.h>
68 #include <vm/vm_param.h>
69 #include <vm/pmap.h>
70 #include <vm/vm_map.h>
71 #include <vm/vm_object.h>
72 
73 #include <machine/cpu.h>
74 
75 #ifdef COMPAT_FREEBSD32
76 #include <compat/freebsd32/freebsd32_proto.h>
77 #endif
78 
79 #define _UMUTEX_TRY		1
80 #define _UMUTEX_WAIT		2
81 
82 #ifdef UMTX_PROFILING
83 #define	UPROF_PERC_BIGGER(w, f, sw, sf)					\
84 	(((w) > (sw)) || ((w) == (sw) && (f) > (sf)))
85 #endif
86 
87 /* Priority inheritance mutex info. */
88 struct umtx_pi {
89 	/* Owner thread */
90 	struct thread		*pi_owner;
91 
92 	/* Reference count */
93 	int			pi_refcount;
94 
95  	/* List entry to link umtx holding by thread */
96 	TAILQ_ENTRY(umtx_pi)	pi_link;
97 
98 	/* List entry in hash */
99 	TAILQ_ENTRY(umtx_pi)	pi_hashlink;
100 
101 	/* List for waiters */
102 	TAILQ_HEAD(,umtx_q)	pi_blocked;
103 
104 	/* Identify a userland lock object */
105 	struct umtx_key		pi_key;
106 };
107 
108 /* A userland synchronous object user. */
109 struct umtx_q {
110 	/* Linked list for the hash. */
111 	TAILQ_ENTRY(umtx_q)	uq_link;
112 
113 	/* Umtx key. */
114 	struct umtx_key		uq_key;
115 
116 	/* Umtx flags. */
117 	int			uq_flags;
118 #define UQF_UMTXQ	0x0001
119 
120 	/* The thread waits on. */
121 	struct thread		*uq_thread;
122 
123 	/*
124 	 * Blocked on PI mutex. read can use chain lock
125 	 * or umtx_lock, write must have both chain lock and
126 	 * umtx_lock being hold.
127 	 */
128 	struct umtx_pi		*uq_pi_blocked;
129 
130 	/* On blocked list */
131 	TAILQ_ENTRY(umtx_q)	uq_lockq;
132 
133 	/* Thread contending with us */
134 	TAILQ_HEAD(,umtx_pi)	uq_pi_contested;
135 
136 	/* Inherited priority from PP mutex */
137 	u_char			uq_inherited_pri;
138 
139 	/* Spare queue ready to be reused */
140 	struct umtxq_queue	*uq_spare_queue;
141 
142 	/* The queue we on */
143 	struct umtxq_queue	*uq_cur_queue;
144 };
145 
146 TAILQ_HEAD(umtxq_head, umtx_q);
147 
148 /* Per-key wait-queue */
149 struct umtxq_queue {
150 	struct umtxq_head	head;
151 	struct umtx_key		key;
152 	LIST_ENTRY(umtxq_queue)	link;
153 	int			length;
154 };
155 
156 LIST_HEAD(umtxq_list, umtxq_queue);
157 
158 /* Userland lock object's wait-queue chain */
159 struct umtxq_chain {
160 	/* Lock for this chain. */
161 	struct mtx		uc_lock;
162 
163 	/* List of sleep queues. */
164 	struct umtxq_list	uc_queue[2];
165 #define UMTX_SHARED_QUEUE	0
166 #define UMTX_EXCLUSIVE_QUEUE	1
167 
168 	LIST_HEAD(, umtxq_queue) uc_spare_queue;
169 
170 	/* Busy flag */
171 	char			uc_busy;
172 
173 	/* Chain lock waiters */
174 	int			uc_waiters;
175 
176 	/* All PI in the list */
177 	TAILQ_HEAD(,umtx_pi)	uc_pi_list;
178 
179 #ifdef UMTX_PROFILING
180 	u_int 			length;
181 	u_int			max_length;
182 #endif
183 };
184 
185 #define	UMTXQ_LOCKED_ASSERT(uc)		mtx_assert(&(uc)->uc_lock, MA_OWNED)
186 
187 /*
188  * Don't propagate time-sharing priority, there is a security reason,
189  * a user can simply introduce PI-mutex, let thread A lock the mutex,
190  * and let another thread B block on the mutex, because B is
191  * sleeping, its priority will be boosted, this causes A's priority to
192  * be boosted via priority propagating too and will never be lowered even
193  * if it is using 100%CPU, this is unfair to other processes.
194  */
195 
196 #define UPRI(td)	(((td)->td_user_pri >= PRI_MIN_TIMESHARE &&\
197 			  (td)->td_user_pri <= PRI_MAX_TIMESHARE) ?\
198 			 PRI_MAX_TIMESHARE : (td)->td_user_pri)
199 
200 #define	GOLDEN_RATIO_PRIME	2654404609U
201 #define	UMTX_CHAINS		512
202 #define	UMTX_SHIFTS		(__WORD_BIT - 9)
203 
204 #define	GET_SHARE(flags)	\
205     (((flags) & USYNC_PROCESS_SHARED) == 0 ? THREAD_SHARE : PROCESS_SHARE)
206 
207 #define BUSY_SPINS		200
208 
209 struct abs_timeout {
210 	int clockid;
211 	struct timespec cur;
212 	struct timespec end;
213 };
214 
215 #ifdef COMPAT_FREEBSD32
216 struct umutex32 {
217 	volatile __lwpid_t	m_owner;	/* Owner of the mutex */
218 	__uint32_t		m_flags;	/* Flags of the mutex */
219 	__uint32_t		m_ceilings[2];	/* Priority protect ceiling */
220 	__uint32_t		m_rb_lnk;	/* Robust linkage */
221 	__uint32_t		m_pad;
222 	__uint32_t		m_spare[2];
223 };
224 
225 _Static_assert(sizeof(struct umutex) == sizeof(struct umutex32), "umutex32");
226 _Static_assert(__offsetof(struct umutex, m_spare[0]) ==
227     __offsetof(struct umutex32, m_spare[0]), "m_spare32");
228 #endif
229 
230 int umtx_shm_vnobj_persistent = 0;
231 SYSCTL_INT(_kern_ipc, OID_AUTO, umtx_vnode_persistent, CTLFLAG_RWTUN,
232     &umtx_shm_vnobj_persistent, 0,
233     "False forces destruction of umtx attached to file, on last close");
234 static int umtx_max_rb = 1000;
235 SYSCTL_INT(_kern_ipc, OID_AUTO, umtx_max_robust, CTLFLAG_RWTUN,
236     &umtx_max_rb, 0,
237     "");
238 
239 static uma_zone_t		umtx_pi_zone;
240 static struct umtxq_chain	umtxq_chains[2][UMTX_CHAINS];
241 static MALLOC_DEFINE(M_UMTX, "umtx", "UMTX queue memory");
242 static int			umtx_pi_allocated;
243 
244 static SYSCTL_NODE(_debug, OID_AUTO, umtx, CTLFLAG_RW, 0, "umtx debug");
245 SYSCTL_INT(_debug_umtx, OID_AUTO, umtx_pi_allocated, CTLFLAG_RD,
246     &umtx_pi_allocated, 0, "Allocated umtx_pi");
247 static int umtx_verbose_rb = 1;
248 SYSCTL_INT(_debug_umtx, OID_AUTO, robust_faults_verbose, CTLFLAG_RWTUN,
249     &umtx_verbose_rb, 0,
250     "");
251 
252 #ifdef UMTX_PROFILING
253 static long max_length;
254 SYSCTL_LONG(_debug_umtx, OID_AUTO, max_length, CTLFLAG_RD, &max_length, 0, "max_length");
255 static SYSCTL_NODE(_debug_umtx, OID_AUTO, chains, CTLFLAG_RD, 0, "umtx chain stats");
256 #endif
257 
258 static void umtx_shm_init(void);
259 static void umtxq_sysinit(void *);
260 static void umtxq_hash(struct umtx_key *key);
261 static struct umtxq_chain *umtxq_getchain(struct umtx_key *key);
262 static void umtxq_lock(struct umtx_key *key);
263 static void umtxq_unlock(struct umtx_key *key);
264 static void umtxq_busy(struct umtx_key *key);
265 static void umtxq_unbusy(struct umtx_key *key);
266 static void umtxq_insert_queue(struct umtx_q *uq, int q);
267 static void umtxq_remove_queue(struct umtx_q *uq, int q);
268 static int umtxq_sleep(struct umtx_q *uq, const char *wmesg, struct abs_timeout *);
269 static int umtxq_count(struct umtx_key *key);
270 static struct umtx_pi *umtx_pi_alloc(int);
271 static void umtx_pi_free(struct umtx_pi *pi);
272 static int do_unlock_pp(struct thread *td, struct umutex *m, uint32_t flags,
273     bool rb);
274 static void umtx_thread_cleanup(struct thread *td);
275 static void umtx_exec_hook(void *arg __unused, struct proc *p __unused,
276     struct image_params *imgp __unused);
277 SYSINIT(umtx, SI_SUB_EVENTHANDLER+1, SI_ORDER_MIDDLE, umtxq_sysinit, NULL);
278 
279 #define umtxq_signal(key, nwake)	umtxq_signal_queue((key), (nwake), UMTX_SHARED_QUEUE)
280 #define umtxq_insert(uq)	umtxq_insert_queue((uq), UMTX_SHARED_QUEUE)
281 #define umtxq_remove(uq)	umtxq_remove_queue((uq), UMTX_SHARED_QUEUE)
282 
283 static struct mtx umtx_lock;
284 
285 #ifdef UMTX_PROFILING
286 static void
287 umtx_init_profiling(void)
288 {
289 	struct sysctl_oid *chain_oid;
290 	char chain_name[10];
291 	int i;
292 
293 	for (i = 0; i < UMTX_CHAINS; ++i) {
294 		snprintf(chain_name, sizeof(chain_name), "%d", i);
295 		chain_oid = SYSCTL_ADD_NODE(NULL,
296 		    SYSCTL_STATIC_CHILDREN(_debug_umtx_chains), OID_AUTO,
297 		    chain_name, CTLFLAG_RD, NULL, "umtx hash stats");
298 		SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
299 		    "max_length0", CTLFLAG_RD, &umtxq_chains[0][i].max_length, 0, NULL);
300 		SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
301 		    "max_length1", CTLFLAG_RD, &umtxq_chains[1][i].max_length, 0, NULL);
302 	}
303 }
304 
305 static int
306 sysctl_debug_umtx_chains_peaks(SYSCTL_HANDLER_ARGS)
307 {
308 	char buf[512];
309 	struct sbuf sb;
310 	struct umtxq_chain *uc;
311 	u_int fract, i, j, tot, whole;
312 	u_int sf0, sf1, sf2, sf3, sf4;
313 	u_int si0, si1, si2, si3, si4;
314 	u_int sw0, sw1, sw2, sw3, sw4;
315 
316 	sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN);
317 	for (i = 0; i < 2; i++) {
318 		tot = 0;
319 		for (j = 0; j < UMTX_CHAINS; ++j) {
320 			uc = &umtxq_chains[i][j];
321 			mtx_lock(&uc->uc_lock);
322 			tot += uc->max_length;
323 			mtx_unlock(&uc->uc_lock);
324 		}
325 		if (tot == 0)
326 			sbuf_printf(&sb, "%u) Empty ", i);
327 		else {
328 			sf0 = sf1 = sf2 = sf3 = sf4 = 0;
329 			si0 = si1 = si2 = si3 = si4 = 0;
330 			sw0 = sw1 = sw2 = sw3 = sw4 = 0;
331 			for (j = 0; j < UMTX_CHAINS; j++) {
332 				uc = &umtxq_chains[i][j];
333 				mtx_lock(&uc->uc_lock);
334 				whole = uc->max_length * 100;
335 				mtx_unlock(&uc->uc_lock);
336 				fract = (whole % tot) * 100;
337 				if (UPROF_PERC_BIGGER(whole, fract, sw0, sf0)) {
338 					sf0 = fract;
339 					si0 = j;
340 					sw0 = whole;
341 				} else if (UPROF_PERC_BIGGER(whole, fract, sw1,
342 				    sf1)) {
343 					sf1 = fract;
344 					si1 = j;
345 					sw1 = whole;
346 				} else if (UPROF_PERC_BIGGER(whole, fract, sw2,
347 				    sf2)) {
348 					sf2 = fract;
349 					si2 = j;
350 					sw2 = whole;
351 				} else if (UPROF_PERC_BIGGER(whole, fract, sw3,
352 				    sf3)) {
353 					sf3 = fract;
354 					si3 = j;
355 					sw3 = whole;
356 				} else if (UPROF_PERC_BIGGER(whole, fract, sw4,
357 				    sf4)) {
358 					sf4 = fract;
359 					si4 = j;
360 					sw4 = whole;
361 				}
362 			}
363 			sbuf_printf(&sb, "queue %u:\n", i);
364 			sbuf_printf(&sb, "1st: %u.%u%% idx: %u\n", sw0 / tot,
365 			    sf0 / tot, si0);
366 			sbuf_printf(&sb, "2nd: %u.%u%% idx: %u\n", sw1 / tot,
367 			    sf1 / tot, si1);
368 			sbuf_printf(&sb, "3rd: %u.%u%% idx: %u\n", sw2 / tot,
369 			    sf2 / tot, si2);
370 			sbuf_printf(&sb, "4th: %u.%u%% idx: %u\n", sw3 / tot,
371 			    sf3 / tot, si3);
372 			sbuf_printf(&sb, "5th: %u.%u%% idx: %u\n", sw4 / tot,
373 			    sf4 / tot, si4);
374 		}
375 	}
376 	sbuf_trim(&sb);
377 	sbuf_finish(&sb);
378 	sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
379 	sbuf_delete(&sb);
380 	return (0);
381 }
382 
383 static int
384 sysctl_debug_umtx_chains_clear(SYSCTL_HANDLER_ARGS)
385 {
386 	struct umtxq_chain *uc;
387 	u_int i, j;
388 	int clear, error;
389 
390 	clear = 0;
391 	error = sysctl_handle_int(oidp, &clear, 0, req);
392 	if (error != 0 || req->newptr == NULL)
393 		return (error);
394 
395 	if (clear != 0) {
396 		for (i = 0; i < 2; ++i) {
397 			for (j = 0; j < UMTX_CHAINS; ++j) {
398 				uc = &umtxq_chains[i][j];
399 				mtx_lock(&uc->uc_lock);
400 				uc->length = 0;
401 				uc->max_length = 0;
402 				mtx_unlock(&uc->uc_lock);
403 			}
404 		}
405 	}
406 	return (0);
407 }
408 
409 SYSCTL_PROC(_debug_umtx_chains, OID_AUTO, clear,
410     CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
411     sysctl_debug_umtx_chains_clear, "I", "Clear umtx chains statistics");
412 SYSCTL_PROC(_debug_umtx_chains, OID_AUTO, peaks,
413     CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
414     sysctl_debug_umtx_chains_peaks, "A", "Highest peaks in chains max length");
415 #endif
416 
417 static void
418 umtxq_sysinit(void *arg __unused)
419 {
420 	int i, j;
421 
422 	umtx_pi_zone = uma_zcreate("umtx pi", sizeof(struct umtx_pi),
423 		NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
424 	for (i = 0; i < 2; ++i) {
425 		for (j = 0; j < UMTX_CHAINS; ++j) {
426 			mtx_init(&umtxq_chains[i][j].uc_lock, "umtxql", NULL,
427 				 MTX_DEF | MTX_DUPOK);
428 			LIST_INIT(&umtxq_chains[i][j].uc_queue[0]);
429 			LIST_INIT(&umtxq_chains[i][j].uc_queue[1]);
430 			LIST_INIT(&umtxq_chains[i][j].uc_spare_queue);
431 			TAILQ_INIT(&umtxq_chains[i][j].uc_pi_list);
432 			umtxq_chains[i][j].uc_busy = 0;
433 			umtxq_chains[i][j].uc_waiters = 0;
434 #ifdef UMTX_PROFILING
435 			umtxq_chains[i][j].length = 0;
436 			umtxq_chains[i][j].max_length = 0;
437 #endif
438 		}
439 	}
440 #ifdef UMTX_PROFILING
441 	umtx_init_profiling();
442 #endif
443 	mtx_init(&umtx_lock, "umtx lock", NULL, MTX_DEF);
444 	EVENTHANDLER_REGISTER(process_exec, umtx_exec_hook, NULL,
445 	    EVENTHANDLER_PRI_ANY);
446 	umtx_shm_init();
447 }
448 
449 struct umtx_q *
450 umtxq_alloc(void)
451 {
452 	struct umtx_q *uq;
453 
454 	uq = malloc(sizeof(struct umtx_q), M_UMTX, M_WAITOK | M_ZERO);
455 	uq->uq_spare_queue = malloc(sizeof(struct umtxq_queue), M_UMTX,
456 	    M_WAITOK | M_ZERO);
457 	TAILQ_INIT(&uq->uq_spare_queue->head);
458 	TAILQ_INIT(&uq->uq_pi_contested);
459 	uq->uq_inherited_pri = PRI_MAX;
460 	return (uq);
461 }
462 
463 void
464 umtxq_free(struct umtx_q *uq)
465 {
466 
467 	MPASS(uq->uq_spare_queue != NULL);
468 	free(uq->uq_spare_queue, M_UMTX);
469 	free(uq, M_UMTX);
470 }
471 
472 static inline void
473 umtxq_hash(struct umtx_key *key)
474 {
475 	unsigned n;
476 
477 	n = (uintptr_t)key->info.both.a + key->info.both.b;
478 	key->hash = ((n * GOLDEN_RATIO_PRIME) >> UMTX_SHIFTS) % UMTX_CHAINS;
479 }
480 
481 static inline struct umtxq_chain *
482 umtxq_getchain(struct umtx_key *key)
483 {
484 
485 	if (key->type <= TYPE_SEM)
486 		return (&umtxq_chains[1][key->hash]);
487 	return (&umtxq_chains[0][key->hash]);
488 }
489 
490 /*
491  * Lock a chain.
492  */
493 static inline void
494 umtxq_lock(struct umtx_key *key)
495 {
496 	struct umtxq_chain *uc;
497 
498 	uc = umtxq_getchain(key);
499 	mtx_lock(&uc->uc_lock);
500 }
501 
502 /*
503  * Unlock a chain.
504  */
505 static inline void
506 umtxq_unlock(struct umtx_key *key)
507 {
508 	struct umtxq_chain *uc;
509 
510 	uc = umtxq_getchain(key);
511 	mtx_unlock(&uc->uc_lock);
512 }
513 
514 /*
515  * Set chain to busy state when following operation
516  * may be blocked (kernel mutex can not be used).
517  */
518 static inline void
519 umtxq_busy(struct umtx_key *key)
520 {
521 	struct umtxq_chain *uc;
522 
523 	uc = umtxq_getchain(key);
524 	mtx_assert(&uc->uc_lock, MA_OWNED);
525 	if (uc->uc_busy) {
526 #ifdef SMP
527 		if (smp_cpus > 1) {
528 			int count = BUSY_SPINS;
529 			if (count > 0) {
530 				umtxq_unlock(key);
531 				while (uc->uc_busy && --count > 0)
532 					cpu_spinwait();
533 				umtxq_lock(key);
534 			}
535 		}
536 #endif
537 		while (uc->uc_busy) {
538 			uc->uc_waiters++;
539 			msleep(uc, &uc->uc_lock, 0, "umtxqb", 0);
540 			uc->uc_waiters--;
541 		}
542 	}
543 	uc->uc_busy = 1;
544 }
545 
546 /*
547  * Unbusy a chain.
548  */
549 static inline void
550 umtxq_unbusy(struct umtx_key *key)
551 {
552 	struct umtxq_chain *uc;
553 
554 	uc = umtxq_getchain(key);
555 	mtx_assert(&uc->uc_lock, MA_OWNED);
556 	KASSERT(uc->uc_busy != 0, ("not busy"));
557 	uc->uc_busy = 0;
558 	if (uc->uc_waiters)
559 		wakeup_one(uc);
560 }
561 
562 static inline void
563 umtxq_unbusy_unlocked(struct umtx_key *key)
564 {
565 
566 	umtxq_lock(key);
567 	umtxq_unbusy(key);
568 	umtxq_unlock(key);
569 }
570 
571 static struct umtxq_queue *
572 umtxq_queue_lookup(struct umtx_key *key, int q)
573 {
574 	struct umtxq_queue *uh;
575 	struct umtxq_chain *uc;
576 
577 	uc = umtxq_getchain(key);
578 	UMTXQ_LOCKED_ASSERT(uc);
579 	LIST_FOREACH(uh, &uc->uc_queue[q], link) {
580 		if (umtx_key_match(&uh->key, key))
581 			return (uh);
582 	}
583 
584 	return (NULL);
585 }
586 
587 static inline void
588 umtxq_insert_queue(struct umtx_q *uq, int q)
589 {
590 	struct umtxq_queue *uh;
591 	struct umtxq_chain *uc;
592 
593 	uc = umtxq_getchain(&uq->uq_key);
594 	UMTXQ_LOCKED_ASSERT(uc);
595 	KASSERT((uq->uq_flags & UQF_UMTXQ) == 0, ("umtx_q is already on queue"));
596 	uh = umtxq_queue_lookup(&uq->uq_key, q);
597 	if (uh != NULL) {
598 		LIST_INSERT_HEAD(&uc->uc_spare_queue, uq->uq_spare_queue, link);
599 	} else {
600 		uh = uq->uq_spare_queue;
601 		uh->key = uq->uq_key;
602 		LIST_INSERT_HEAD(&uc->uc_queue[q], uh, link);
603 #ifdef UMTX_PROFILING
604 		uc->length++;
605 		if (uc->length > uc->max_length) {
606 			uc->max_length = uc->length;
607 			if (uc->max_length > max_length)
608 				max_length = uc->max_length;
609 		}
610 #endif
611 	}
612 	uq->uq_spare_queue = NULL;
613 
614 	TAILQ_INSERT_TAIL(&uh->head, uq, uq_link);
615 	uh->length++;
616 	uq->uq_flags |= UQF_UMTXQ;
617 	uq->uq_cur_queue = uh;
618 	return;
619 }
620 
621 static inline void
622 umtxq_remove_queue(struct umtx_q *uq, int q)
623 {
624 	struct umtxq_chain *uc;
625 	struct umtxq_queue *uh;
626 
627 	uc = umtxq_getchain(&uq->uq_key);
628 	UMTXQ_LOCKED_ASSERT(uc);
629 	if (uq->uq_flags & UQF_UMTXQ) {
630 		uh = uq->uq_cur_queue;
631 		TAILQ_REMOVE(&uh->head, uq, uq_link);
632 		uh->length--;
633 		uq->uq_flags &= ~UQF_UMTXQ;
634 		if (TAILQ_EMPTY(&uh->head)) {
635 			KASSERT(uh->length == 0,
636 			    ("inconsistent umtxq_queue length"));
637 #ifdef UMTX_PROFILING
638 			uc->length--;
639 #endif
640 			LIST_REMOVE(uh, link);
641 		} else {
642 			uh = LIST_FIRST(&uc->uc_spare_queue);
643 			KASSERT(uh != NULL, ("uc_spare_queue is empty"));
644 			LIST_REMOVE(uh, link);
645 		}
646 		uq->uq_spare_queue = uh;
647 		uq->uq_cur_queue = NULL;
648 	}
649 }
650 
651 /*
652  * Check if there are multiple waiters
653  */
654 static int
655 umtxq_count(struct umtx_key *key)
656 {
657 	struct umtxq_chain *uc;
658 	struct umtxq_queue *uh;
659 
660 	uc = umtxq_getchain(key);
661 	UMTXQ_LOCKED_ASSERT(uc);
662 	uh = umtxq_queue_lookup(key, UMTX_SHARED_QUEUE);
663 	if (uh != NULL)
664 		return (uh->length);
665 	return (0);
666 }
667 
668 /*
669  * Check if there are multiple PI waiters and returns first
670  * waiter.
671  */
672 static int
673 umtxq_count_pi(struct umtx_key *key, struct umtx_q **first)
674 {
675 	struct umtxq_chain *uc;
676 	struct umtxq_queue *uh;
677 
678 	*first = NULL;
679 	uc = umtxq_getchain(key);
680 	UMTXQ_LOCKED_ASSERT(uc);
681 	uh = umtxq_queue_lookup(key, UMTX_SHARED_QUEUE);
682 	if (uh != NULL) {
683 		*first = TAILQ_FIRST(&uh->head);
684 		return (uh->length);
685 	}
686 	return (0);
687 }
688 
689 static int
690 umtxq_check_susp(struct thread *td)
691 {
692 	struct proc *p;
693 	int error;
694 
695 	/*
696 	 * The check for TDF_NEEDSUSPCHK is racy, but it is enough to
697 	 * eventually break the lockstep loop.
698 	 */
699 	if ((td->td_flags & TDF_NEEDSUSPCHK) == 0)
700 		return (0);
701 	error = 0;
702 	p = td->td_proc;
703 	PROC_LOCK(p);
704 	if (P_SHOULDSTOP(p) ||
705 	    ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_SUSPEND))) {
706 		if (p->p_flag & P_SINGLE_EXIT)
707 			error = EINTR;
708 		else
709 			error = ERESTART;
710 	}
711 	PROC_UNLOCK(p);
712 	return (error);
713 }
714 
715 /*
716  * Wake up threads waiting on an userland object.
717  */
718 
719 static int
720 umtxq_signal_queue(struct umtx_key *key, int n_wake, int q)
721 {
722 	struct umtxq_chain *uc;
723 	struct umtxq_queue *uh;
724 	struct umtx_q *uq;
725 	int ret;
726 
727 	ret = 0;
728 	uc = umtxq_getchain(key);
729 	UMTXQ_LOCKED_ASSERT(uc);
730 	uh = umtxq_queue_lookup(key, q);
731 	if (uh != NULL) {
732 		while ((uq = TAILQ_FIRST(&uh->head)) != NULL) {
733 			umtxq_remove_queue(uq, q);
734 			wakeup(uq);
735 			if (++ret >= n_wake)
736 				return (ret);
737 		}
738 	}
739 	return (ret);
740 }
741 
742 
743 /*
744  * Wake up specified thread.
745  */
746 static inline void
747 umtxq_signal_thread(struct umtx_q *uq)
748 {
749 	struct umtxq_chain *uc;
750 
751 	uc = umtxq_getchain(&uq->uq_key);
752 	UMTXQ_LOCKED_ASSERT(uc);
753 	umtxq_remove(uq);
754 	wakeup(uq);
755 }
756 
757 static inline int
758 tstohz(const struct timespec *tsp)
759 {
760 	struct timeval tv;
761 
762 	TIMESPEC_TO_TIMEVAL(&tv, tsp);
763 	return tvtohz(&tv);
764 }
765 
766 static void
767 abs_timeout_init(struct abs_timeout *timo, int clockid, int absolute,
768 	const struct timespec *timeout)
769 {
770 
771 	timo->clockid = clockid;
772 	if (!absolute) {
773 		kern_clock_gettime(curthread, clockid, &timo->end);
774 		timo->cur = timo->end;
775 		timespecadd(&timo->end, timeout);
776 	} else {
777 		timo->end = *timeout;
778 		kern_clock_gettime(curthread, clockid, &timo->cur);
779 	}
780 }
781 
782 static void
783 abs_timeout_init2(struct abs_timeout *timo, const struct _umtx_time *umtxtime)
784 {
785 
786 	abs_timeout_init(timo, umtxtime->_clockid,
787 	    (umtxtime->_flags & UMTX_ABSTIME) != 0, &umtxtime->_timeout);
788 }
789 
790 static inline void
791 abs_timeout_update(struct abs_timeout *timo)
792 {
793 
794 	kern_clock_gettime(curthread, timo->clockid, &timo->cur);
795 }
796 
797 static int
798 abs_timeout_gethz(struct abs_timeout *timo)
799 {
800 	struct timespec tts;
801 
802 	if (timespeccmp(&timo->end, &timo->cur, <=))
803 		return (-1);
804 	tts = timo->end;
805 	timespecsub(&tts, &timo->cur);
806 	return (tstohz(&tts));
807 }
808 
809 static uint32_t
810 umtx_unlock_val(uint32_t flags, bool rb)
811 {
812 
813 	if (rb)
814 		return (UMUTEX_RB_OWNERDEAD);
815 	else if ((flags & UMUTEX_NONCONSISTENT) != 0)
816 		return (UMUTEX_RB_NOTRECOV);
817 	else
818 		return (UMUTEX_UNOWNED);
819 
820 }
821 
822 /*
823  * Put thread into sleep state, before sleeping, check if
824  * thread was removed from umtx queue.
825  */
826 static inline int
827 umtxq_sleep(struct umtx_q *uq, const char *wmesg, struct abs_timeout *abstime)
828 {
829 	struct umtxq_chain *uc;
830 	int error, timo;
831 
832 	uc = umtxq_getchain(&uq->uq_key);
833 	UMTXQ_LOCKED_ASSERT(uc);
834 	for (;;) {
835 		if (!(uq->uq_flags & UQF_UMTXQ))
836 			return (0);
837 		if (abstime != NULL) {
838 			timo = abs_timeout_gethz(abstime);
839 			if (timo < 0)
840 				return (ETIMEDOUT);
841 		} else
842 			timo = 0;
843 		error = msleep(uq, &uc->uc_lock, PCATCH | PDROP, wmesg, timo);
844 		if (error != EWOULDBLOCK) {
845 			umtxq_lock(&uq->uq_key);
846 			break;
847 		}
848 		if (abstime != NULL)
849 			abs_timeout_update(abstime);
850 		umtxq_lock(&uq->uq_key);
851 	}
852 	return (error);
853 }
854 
855 /*
856  * Convert userspace address into unique logical address.
857  */
858 int
859 umtx_key_get(const void *addr, int type, int share, struct umtx_key *key)
860 {
861 	struct thread *td = curthread;
862 	vm_map_t map;
863 	vm_map_entry_t entry;
864 	vm_pindex_t pindex;
865 	vm_prot_t prot;
866 	boolean_t wired;
867 
868 	key->type = type;
869 	if (share == THREAD_SHARE) {
870 		key->shared = 0;
871 		key->info.private.vs = td->td_proc->p_vmspace;
872 		key->info.private.addr = (uintptr_t)addr;
873 	} else {
874 		MPASS(share == PROCESS_SHARE || share == AUTO_SHARE);
875 		map = &td->td_proc->p_vmspace->vm_map;
876 		if (vm_map_lookup(&map, (vm_offset_t)addr, VM_PROT_WRITE,
877 		    &entry, &key->info.shared.object, &pindex, &prot,
878 		    &wired) != KERN_SUCCESS) {
879 			return (EFAULT);
880 		}
881 
882 		if ((share == PROCESS_SHARE) ||
883 		    (share == AUTO_SHARE &&
884 		     VM_INHERIT_SHARE == entry->inheritance)) {
885 			key->shared = 1;
886 			key->info.shared.offset = (vm_offset_t)addr -
887 			    entry->start + entry->offset;
888 			vm_object_reference(key->info.shared.object);
889 		} else {
890 			key->shared = 0;
891 			key->info.private.vs = td->td_proc->p_vmspace;
892 			key->info.private.addr = (uintptr_t)addr;
893 		}
894 		vm_map_lookup_done(map, entry);
895 	}
896 
897 	umtxq_hash(key);
898 	return (0);
899 }
900 
901 /*
902  * Release key.
903  */
904 void
905 umtx_key_release(struct umtx_key *key)
906 {
907 	if (key->shared)
908 		vm_object_deallocate(key->info.shared.object);
909 }
910 
911 /*
912  * Fetch and compare value, sleep on the address if value is not changed.
913  */
914 static int
915 do_wait(struct thread *td, void *addr, u_long id,
916     struct _umtx_time *timeout, int compat32, int is_private)
917 {
918 	struct abs_timeout timo;
919 	struct umtx_q *uq;
920 	u_long tmp;
921 	uint32_t tmp32;
922 	int error = 0;
923 
924 	uq = td->td_umtxq;
925 	if ((error = umtx_key_get(addr, TYPE_SIMPLE_WAIT,
926 		is_private ? THREAD_SHARE : AUTO_SHARE, &uq->uq_key)) != 0)
927 		return (error);
928 
929 	if (timeout != NULL)
930 		abs_timeout_init2(&timo, timeout);
931 
932 	umtxq_lock(&uq->uq_key);
933 	umtxq_insert(uq);
934 	umtxq_unlock(&uq->uq_key);
935 	if (compat32 == 0) {
936 		error = fueword(addr, &tmp);
937 		if (error != 0)
938 			error = EFAULT;
939 	} else {
940 		error = fueword32(addr, &tmp32);
941 		if (error == 0)
942 			tmp = tmp32;
943 		else
944 			error = EFAULT;
945 	}
946 	umtxq_lock(&uq->uq_key);
947 	if (error == 0) {
948 		if (tmp == id)
949 			error = umtxq_sleep(uq, "uwait", timeout == NULL ?
950 			    NULL : &timo);
951 		if ((uq->uq_flags & UQF_UMTXQ) == 0)
952 			error = 0;
953 		else
954 			umtxq_remove(uq);
955 	} else if ((uq->uq_flags & UQF_UMTXQ) != 0) {
956 		umtxq_remove(uq);
957 	}
958 	umtxq_unlock(&uq->uq_key);
959 	umtx_key_release(&uq->uq_key);
960 	if (error == ERESTART)
961 		error = EINTR;
962 	return (error);
963 }
964 
965 /*
966  * Wake up threads sleeping on the specified address.
967  */
968 int
969 kern_umtx_wake(struct thread *td, void *uaddr, int n_wake, int is_private)
970 {
971 	struct umtx_key key;
972 	int ret;
973 
974 	if ((ret = umtx_key_get(uaddr, TYPE_SIMPLE_WAIT,
975 	    is_private ? THREAD_SHARE : AUTO_SHARE, &key)) != 0)
976 		return (ret);
977 	umtxq_lock(&key);
978 	umtxq_signal(&key, n_wake);
979 	umtxq_unlock(&key);
980 	umtx_key_release(&key);
981 	return (0);
982 }
983 
984 /*
985  * Lock PTHREAD_PRIO_NONE protocol POSIX mutex.
986  */
987 static int
988 do_lock_normal(struct thread *td, struct umutex *m, uint32_t flags,
989     struct _umtx_time *timeout, int mode)
990 {
991 	struct abs_timeout timo;
992 	struct umtx_q *uq;
993 	uint32_t owner, old, id;
994 	int error, rv;
995 
996 	id = td->td_tid;
997 	uq = td->td_umtxq;
998 	error = 0;
999 	if (timeout != NULL)
1000 		abs_timeout_init2(&timo, timeout);
1001 
1002 	/*
1003 	 * Care must be exercised when dealing with umtx structure. It
1004 	 * can fault on any access.
1005 	 */
1006 	for (;;) {
1007 		rv = fueword32(&m->m_owner, &owner);
1008 		if (rv == -1)
1009 			return (EFAULT);
1010 		if (mode == _UMUTEX_WAIT) {
1011 			if (owner == UMUTEX_UNOWNED ||
1012 			    owner == UMUTEX_CONTESTED ||
1013 			    owner == UMUTEX_RB_OWNERDEAD ||
1014 			    owner == UMUTEX_RB_NOTRECOV)
1015 				return (0);
1016 		} else {
1017 			/*
1018 			 * Robust mutex terminated.  Kernel duty is to
1019 			 * return EOWNERDEAD to the userspace.  The
1020 			 * umutex.m_flags UMUTEX_NONCONSISTENT is set
1021 			 * by the common userspace code.
1022 			 */
1023 			if (owner == UMUTEX_RB_OWNERDEAD) {
1024 				rv = casueword32(&m->m_owner,
1025 				    UMUTEX_RB_OWNERDEAD, &owner,
1026 				    id | UMUTEX_CONTESTED);
1027 				if (rv == -1)
1028 					return (EFAULT);
1029 				if (owner == UMUTEX_RB_OWNERDEAD)
1030 					return (EOWNERDEAD); /* success */
1031 				rv = umtxq_check_susp(td);
1032 				if (rv != 0)
1033 					return (rv);
1034 				continue;
1035 			}
1036 			if (owner == UMUTEX_RB_NOTRECOV)
1037 				return (ENOTRECOVERABLE);
1038 
1039 
1040 			/*
1041 			 * Try the uncontested case.  This should be
1042 			 * done in userland.
1043 			 */
1044 			rv = casueword32(&m->m_owner, UMUTEX_UNOWNED,
1045 			    &owner, id);
1046 			/* The address was invalid. */
1047 			if (rv == -1)
1048 				return (EFAULT);
1049 
1050 			/* The acquire succeeded. */
1051 			if (owner == UMUTEX_UNOWNED)
1052 				return (0);
1053 
1054 			/*
1055 			 * If no one owns it but it is contested try
1056 			 * to acquire it.
1057 			 */
1058 			if (owner == UMUTEX_CONTESTED) {
1059 				rv = casueword32(&m->m_owner,
1060 				    UMUTEX_CONTESTED, &owner,
1061 				    id | UMUTEX_CONTESTED);
1062 				/* The address was invalid. */
1063 				if (rv == -1)
1064 					return (EFAULT);
1065 
1066 				if (owner == UMUTEX_CONTESTED)
1067 					return (0);
1068 
1069 				rv = umtxq_check_susp(td);
1070 				if (rv != 0)
1071 					return (rv);
1072 
1073 				/*
1074 				 * If this failed the lock has
1075 				 * changed, restart.
1076 				 */
1077 				continue;
1078 			}
1079 		}
1080 
1081 		if (mode == _UMUTEX_TRY)
1082 			return (EBUSY);
1083 
1084 		/*
1085 		 * If we caught a signal, we have retried and now
1086 		 * exit immediately.
1087 		 */
1088 		if (error != 0)
1089 			return (error);
1090 
1091 		if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX,
1092 		    GET_SHARE(flags), &uq->uq_key)) != 0)
1093 			return (error);
1094 
1095 		umtxq_lock(&uq->uq_key);
1096 		umtxq_busy(&uq->uq_key);
1097 		umtxq_insert(uq);
1098 		umtxq_unlock(&uq->uq_key);
1099 
1100 		/*
1101 		 * Set the contested bit so that a release in user space
1102 		 * knows to use the system call for unlock.  If this fails
1103 		 * either some one else has acquired the lock or it has been
1104 		 * released.
1105 		 */
1106 		rv = casueword32(&m->m_owner, owner, &old,
1107 		    owner | UMUTEX_CONTESTED);
1108 
1109 		/* The address was invalid. */
1110 		if (rv == -1) {
1111 			umtxq_lock(&uq->uq_key);
1112 			umtxq_remove(uq);
1113 			umtxq_unbusy(&uq->uq_key);
1114 			umtxq_unlock(&uq->uq_key);
1115 			umtx_key_release(&uq->uq_key);
1116 			return (EFAULT);
1117 		}
1118 
1119 		/*
1120 		 * We set the contested bit, sleep. Otherwise the lock changed
1121 		 * and we need to retry or we lost a race to the thread
1122 		 * unlocking the umtx.
1123 		 */
1124 		umtxq_lock(&uq->uq_key);
1125 		umtxq_unbusy(&uq->uq_key);
1126 		if (old == owner)
1127 			error = umtxq_sleep(uq, "umtxn", timeout == NULL ?
1128 			    NULL : &timo);
1129 		umtxq_remove(uq);
1130 		umtxq_unlock(&uq->uq_key);
1131 		umtx_key_release(&uq->uq_key);
1132 
1133 		if (error == 0)
1134 			error = umtxq_check_susp(td);
1135 	}
1136 
1137 	return (0);
1138 }
1139 
1140 /*
1141  * Unlock PTHREAD_PRIO_NONE protocol POSIX mutex.
1142  */
1143 static int
1144 do_unlock_normal(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
1145 {
1146 	struct umtx_key key;
1147 	uint32_t owner, old, id, newlock;
1148 	int error, count;
1149 
1150 	id = td->td_tid;
1151 	/*
1152 	 * Make sure we own this mtx.
1153 	 */
1154 	error = fueword32(&m->m_owner, &owner);
1155 	if (error == -1)
1156 		return (EFAULT);
1157 
1158 	if ((owner & ~UMUTEX_CONTESTED) != id)
1159 		return (EPERM);
1160 
1161 	newlock = umtx_unlock_val(flags, rb);
1162 	if ((owner & UMUTEX_CONTESTED) == 0) {
1163 		error = casueword32(&m->m_owner, owner, &old, newlock);
1164 		if (error == -1)
1165 			return (EFAULT);
1166 		if (old == owner)
1167 			return (0);
1168 		owner = old;
1169 	}
1170 
1171 	/* We should only ever be in here for contested locks */
1172 	if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX, GET_SHARE(flags),
1173 	    &key)) != 0)
1174 		return (error);
1175 
1176 	umtxq_lock(&key);
1177 	umtxq_busy(&key);
1178 	count = umtxq_count(&key);
1179 	umtxq_unlock(&key);
1180 
1181 	/*
1182 	 * When unlocking the umtx, it must be marked as unowned if
1183 	 * there is zero or one thread only waiting for it.
1184 	 * Otherwise, it must be marked as contested.
1185 	 */
1186 	if (count > 1)
1187 		newlock |= UMUTEX_CONTESTED;
1188 	error = casueword32(&m->m_owner, owner, &old, newlock);
1189 	umtxq_lock(&key);
1190 	umtxq_signal(&key, 1);
1191 	umtxq_unbusy(&key);
1192 	umtxq_unlock(&key);
1193 	umtx_key_release(&key);
1194 	if (error == -1)
1195 		return (EFAULT);
1196 	if (old != owner)
1197 		return (EINVAL);
1198 	return (0);
1199 }
1200 
1201 /*
1202  * Check if the mutex is available and wake up a waiter,
1203  * only for simple mutex.
1204  */
1205 static int
1206 do_wake_umutex(struct thread *td, struct umutex *m)
1207 {
1208 	struct umtx_key key;
1209 	uint32_t owner;
1210 	uint32_t flags;
1211 	int error;
1212 	int count;
1213 
1214 	error = fueword32(&m->m_owner, &owner);
1215 	if (error == -1)
1216 		return (EFAULT);
1217 
1218 	if ((owner & ~UMUTEX_CONTESTED) != 0 && owner != UMUTEX_RB_OWNERDEAD &&
1219 	    owner != UMUTEX_RB_NOTRECOV)
1220 		return (0);
1221 
1222 	error = fueword32(&m->m_flags, &flags);
1223 	if (error == -1)
1224 		return (EFAULT);
1225 
1226 	/* We should only ever be in here for contested locks */
1227 	if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX, GET_SHARE(flags),
1228 	    &key)) != 0)
1229 		return (error);
1230 
1231 	umtxq_lock(&key);
1232 	umtxq_busy(&key);
1233 	count = umtxq_count(&key);
1234 	umtxq_unlock(&key);
1235 
1236 	if (count <= 1 && owner != UMUTEX_RB_OWNERDEAD &&
1237 	    owner != UMUTEX_RB_NOTRECOV) {
1238 		error = casueword32(&m->m_owner, UMUTEX_CONTESTED, &owner,
1239 		    UMUTEX_UNOWNED);
1240 		if (error == -1)
1241 			error = EFAULT;
1242 	}
1243 
1244 	umtxq_lock(&key);
1245 	if (error == 0 && count != 0 && ((owner & ~UMUTEX_CONTESTED) == 0 ||
1246 	    owner == UMUTEX_RB_OWNERDEAD || owner == UMUTEX_RB_NOTRECOV))
1247 		umtxq_signal(&key, 1);
1248 	umtxq_unbusy(&key);
1249 	umtxq_unlock(&key);
1250 	umtx_key_release(&key);
1251 	return (error);
1252 }
1253 
1254 /*
1255  * Check if the mutex has waiters and tries to fix contention bit.
1256  */
1257 static int
1258 do_wake2_umutex(struct thread *td, struct umutex *m, uint32_t flags)
1259 {
1260 	struct umtx_key key;
1261 	uint32_t owner, old;
1262 	int type;
1263 	int error;
1264 	int count;
1265 
1266 	switch (flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT |
1267 	    UMUTEX_ROBUST)) {
1268 	case 0:
1269 	case UMUTEX_ROBUST:
1270 		type = TYPE_NORMAL_UMUTEX;
1271 		break;
1272 	case UMUTEX_PRIO_INHERIT:
1273 		type = TYPE_PI_UMUTEX;
1274 		break;
1275 	case (UMUTEX_PRIO_INHERIT | UMUTEX_ROBUST):
1276 		type = TYPE_PI_ROBUST_UMUTEX;
1277 		break;
1278 	case UMUTEX_PRIO_PROTECT:
1279 		type = TYPE_PP_UMUTEX;
1280 		break;
1281 	case (UMUTEX_PRIO_PROTECT | UMUTEX_ROBUST):
1282 		type = TYPE_PP_ROBUST_UMUTEX;
1283 		break;
1284 	default:
1285 		return (EINVAL);
1286 	}
1287 	if ((error = umtx_key_get(m, type, GET_SHARE(flags), &key)) != 0)
1288 		return (error);
1289 
1290 	owner = 0;
1291 	umtxq_lock(&key);
1292 	umtxq_busy(&key);
1293 	count = umtxq_count(&key);
1294 	umtxq_unlock(&key);
1295 	/*
1296 	 * Only repair contention bit if there is a waiter, this means the mutex
1297 	 * is still being referenced by userland code, otherwise don't update
1298 	 * any memory.
1299 	 */
1300 	if (count > 1) {
1301 		error = fueword32(&m->m_owner, &owner);
1302 		if (error == -1)
1303 			error = EFAULT;
1304 		while (error == 0 && (owner & UMUTEX_CONTESTED) == 0) {
1305 			error = casueword32(&m->m_owner, owner, &old,
1306 			    owner | UMUTEX_CONTESTED);
1307 			if (error == -1) {
1308 				error = EFAULT;
1309 				break;
1310 			}
1311 			if (old == owner)
1312 				break;
1313 			owner = old;
1314 			error = umtxq_check_susp(td);
1315 			if (error != 0)
1316 				break;
1317 		}
1318 	} else if (count == 1) {
1319 		error = fueword32(&m->m_owner, &owner);
1320 		if (error == -1)
1321 			error = EFAULT;
1322 		while (error == 0 && (owner & ~UMUTEX_CONTESTED) != 0 &&
1323 		    (owner & UMUTEX_CONTESTED) == 0) {
1324 			error = casueword32(&m->m_owner, owner, &old,
1325 			    owner | UMUTEX_CONTESTED);
1326 			if (error == -1) {
1327 				error = EFAULT;
1328 				break;
1329 			}
1330 			if (old == owner)
1331 				break;
1332 			owner = old;
1333 			error = umtxq_check_susp(td);
1334 			if (error != 0)
1335 				break;
1336 		}
1337 	}
1338 	umtxq_lock(&key);
1339 	if (error == EFAULT) {
1340 		umtxq_signal(&key, INT_MAX);
1341 	} else if (count != 0 && ((owner & ~UMUTEX_CONTESTED) == 0 ||
1342 	    owner == UMUTEX_RB_OWNERDEAD || owner == UMUTEX_RB_NOTRECOV))
1343 		umtxq_signal(&key, 1);
1344 	umtxq_unbusy(&key);
1345 	umtxq_unlock(&key);
1346 	umtx_key_release(&key);
1347 	return (error);
1348 }
1349 
1350 static inline struct umtx_pi *
1351 umtx_pi_alloc(int flags)
1352 {
1353 	struct umtx_pi *pi;
1354 
1355 	pi = uma_zalloc(umtx_pi_zone, M_ZERO | flags);
1356 	TAILQ_INIT(&pi->pi_blocked);
1357 	atomic_add_int(&umtx_pi_allocated, 1);
1358 	return (pi);
1359 }
1360 
1361 static inline void
1362 umtx_pi_free(struct umtx_pi *pi)
1363 {
1364 	uma_zfree(umtx_pi_zone, pi);
1365 	atomic_add_int(&umtx_pi_allocated, -1);
1366 }
1367 
1368 /*
1369  * Adjust the thread's position on a pi_state after its priority has been
1370  * changed.
1371  */
1372 static int
1373 umtx_pi_adjust_thread(struct umtx_pi *pi, struct thread *td)
1374 {
1375 	struct umtx_q *uq, *uq1, *uq2;
1376 	struct thread *td1;
1377 
1378 	mtx_assert(&umtx_lock, MA_OWNED);
1379 	if (pi == NULL)
1380 		return (0);
1381 
1382 	uq = td->td_umtxq;
1383 
1384 	/*
1385 	 * Check if the thread needs to be moved on the blocked chain.
1386 	 * It needs to be moved if either its priority is lower than
1387 	 * the previous thread or higher than the next thread.
1388 	 */
1389 	uq1 = TAILQ_PREV(uq, umtxq_head, uq_lockq);
1390 	uq2 = TAILQ_NEXT(uq, uq_lockq);
1391 	if ((uq1 != NULL && UPRI(td) < UPRI(uq1->uq_thread)) ||
1392 	    (uq2 != NULL && UPRI(td) > UPRI(uq2->uq_thread))) {
1393 		/*
1394 		 * Remove thread from blocked chain and determine where
1395 		 * it should be moved to.
1396 		 */
1397 		TAILQ_REMOVE(&pi->pi_blocked, uq, uq_lockq);
1398 		TAILQ_FOREACH(uq1, &pi->pi_blocked, uq_lockq) {
1399 			td1 = uq1->uq_thread;
1400 			MPASS(td1->td_proc->p_magic == P_MAGIC);
1401 			if (UPRI(td1) > UPRI(td))
1402 				break;
1403 		}
1404 
1405 		if (uq1 == NULL)
1406 			TAILQ_INSERT_TAIL(&pi->pi_blocked, uq, uq_lockq);
1407 		else
1408 			TAILQ_INSERT_BEFORE(uq1, uq, uq_lockq);
1409 	}
1410 	return (1);
1411 }
1412 
1413 static struct umtx_pi *
1414 umtx_pi_next(struct umtx_pi *pi)
1415 {
1416 	struct umtx_q *uq_owner;
1417 
1418 	if (pi->pi_owner == NULL)
1419 		return (NULL);
1420 	uq_owner = pi->pi_owner->td_umtxq;
1421 	if (uq_owner == NULL)
1422 		return (NULL);
1423 	return (uq_owner->uq_pi_blocked);
1424 }
1425 
1426 /*
1427  * Floyd's Cycle-Finding Algorithm.
1428  */
1429 static bool
1430 umtx_pi_check_loop(struct umtx_pi *pi)
1431 {
1432 	struct umtx_pi *pi1;	/* fast iterator */
1433 
1434 	mtx_assert(&umtx_lock, MA_OWNED);
1435 	if (pi == NULL)
1436 		return (false);
1437 	pi1 = pi;
1438 	for (;;) {
1439 		pi = umtx_pi_next(pi);
1440 		if (pi == NULL)
1441 			break;
1442 		pi1 = umtx_pi_next(pi1);
1443 		if (pi1 == NULL)
1444 			break;
1445 		pi1 = umtx_pi_next(pi1);
1446 		if (pi1 == NULL)
1447 			break;
1448 		if (pi == pi1)
1449 			return (true);
1450 	}
1451 	return (false);
1452 }
1453 
1454 /*
1455  * Propagate priority when a thread is blocked on POSIX
1456  * PI mutex.
1457  */
1458 static void
1459 umtx_propagate_priority(struct thread *td)
1460 {
1461 	struct umtx_q *uq;
1462 	struct umtx_pi *pi;
1463 	int pri;
1464 
1465 	mtx_assert(&umtx_lock, MA_OWNED);
1466 	pri = UPRI(td);
1467 	uq = td->td_umtxq;
1468 	pi = uq->uq_pi_blocked;
1469 	if (pi == NULL)
1470 		return;
1471 	if (umtx_pi_check_loop(pi))
1472 		return;
1473 
1474 	for (;;) {
1475 		td = pi->pi_owner;
1476 		if (td == NULL || td == curthread)
1477 			return;
1478 
1479 		MPASS(td->td_proc != NULL);
1480 		MPASS(td->td_proc->p_magic == P_MAGIC);
1481 
1482 		thread_lock(td);
1483 		if (td->td_lend_user_pri > pri)
1484 			sched_lend_user_prio(td, pri);
1485 		else {
1486 			thread_unlock(td);
1487 			break;
1488 		}
1489 		thread_unlock(td);
1490 
1491 		/*
1492 		 * Pick up the lock that td is blocked on.
1493 		 */
1494 		uq = td->td_umtxq;
1495 		pi = uq->uq_pi_blocked;
1496 		if (pi == NULL)
1497 			break;
1498 		/* Resort td on the list if needed. */
1499 		umtx_pi_adjust_thread(pi, td);
1500 	}
1501 }
1502 
1503 /*
1504  * Unpropagate priority for a PI mutex when a thread blocked on
1505  * it is interrupted by signal or resumed by others.
1506  */
1507 static void
1508 umtx_repropagate_priority(struct umtx_pi *pi)
1509 {
1510 	struct umtx_q *uq, *uq_owner;
1511 	struct umtx_pi *pi2;
1512 	int pri;
1513 
1514 	mtx_assert(&umtx_lock, MA_OWNED);
1515 
1516 	if (umtx_pi_check_loop(pi))
1517 		return;
1518 	while (pi != NULL && pi->pi_owner != NULL) {
1519 		pri = PRI_MAX;
1520 		uq_owner = pi->pi_owner->td_umtxq;
1521 
1522 		TAILQ_FOREACH(pi2, &uq_owner->uq_pi_contested, pi_link) {
1523 			uq = TAILQ_FIRST(&pi2->pi_blocked);
1524 			if (uq != NULL) {
1525 				if (pri > UPRI(uq->uq_thread))
1526 					pri = UPRI(uq->uq_thread);
1527 			}
1528 		}
1529 
1530 		if (pri > uq_owner->uq_inherited_pri)
1531 			pri = uq_owner->uq_inherited_pri;
1532 		thread_lock(pi->pi_owner);
1533 		sched_lend_user_prio(pi->pi_owner, pri);
1534 		thread_unlock(pi->pi_owner);
1535 		if ((pi = uq_owner->uq_pi_blocked) != NULL)
1536 			umtx_pi_adjust_thread(pi, uq_owner->uq_thread);
1537 	}
1538 }
1539 
1540 /*
1541  * Insert a PI mutex into owned list.
1542  */
1543 static void
1544 umtx_pi_setowner(struct umtx_pi *pi, struct thread *owner)
1545 {
1546 	struct umtx_q *uq_owner;
1547 
1548 	uq_owner = owner->td_umtxq;
1549 	mtx_assert(&umtx_lock, MA_OWNED);
1550 	if (pi->pi_owner != NULL)
1551 		panic("pi_owner != NULL");
1552 	pi->pi_owner = owner;
1553 	TAILQ_INSERT_TAIL(&uq_owner->uq_pi_contested, pi, pi_link);
1554 }
1555 
1556 
1557 /*
1558  * Disown a PI mutex, and remove it from the owned list.
1559  */
1560 static void
1561 umtx_pi_disown(struct umtx_pi *pi)
1562 {
1563 
1564 	mtx_assert(&umtx_lock, MA_OWNED);
1565 	TAILQ_REMOVE(&pi->pi_owner->td_umtxq->uq_pi_contested, pi, pi_link);
1566 	pi->pi_owner = NULL;
1567 }
1568 
1569 /*
1570  * Claim ownership of a PI mutex.
1571  */
1572 static int
1573 umtx_pi_claim(struct umtx_pi *pi, struct thread *owner)
1574 {
1575 	struct umtx_q *uq;
1576 	int pri;
1577 
1578 	mtx_lock(&umtx_lock);
1579 	if (pi->pi_owner == owner) {
1580 		mtx_unlock(&umtx_lock);
1581 		return (0);
1582 	}
1583 
1584 	if (pi->pi_owner != NULL) {
1585 		/*
1586 		 * userland may have already messed the mutex, sigh.
1587 		 */
1588 		mtx_unlock(&umtx_lock);
1589 		return (EPERM);
1590 	}
1591 	umtx_pi_setowner(pi, owner);
1592 	uq = TAILQ_FIRST(&pi->pi_blocked);
1593 	if (uq != NULL) {
1594 		pri = UPRI(uq->uq_thread);
1595 		thread_lock(owner);
1596 		if (pri < UPRI(owner))
1597 			sched_lend_user_prio(owner, pri);
1598 		thread_unlock(owner);
1599 	}
1600 	mtx_unlock(&umtx_lock);
1601 	return (0);
1602 }
1603 
1604 /*
1605  * Adjust a thread's order position in its blocked PI mutex,
1606  * this may result new priority propagating process.
1607  */
1608 void
1609 umtx_pi_adjust(struct thread *td, u_char oldpri)
1610 {
1611 	struct umtx_q *uq;
1612 	struct umtx_pi *pi;
1613 
1614 	uq = td->td_umtxq;
1615 	mtx_lock(&umtx_lock);
1616 	/*
1617 	 * Pick up the lock that td is blocked on.
1618 	 */
1619 	pi = uq->uq_pi_blocked;
1620 	if (pi != NULL) {
1621 		umtx_pi_adjust_thread(pi, td);
1622 		umtx_repropagate_priority(pi);
1623 	}
1624 	mtx_unlock(&umtx_lock);
1625 }
1626 
1627 /*
1628  * Sleep on a PI mutex.
1629  */
1630 static int
1631 umtxq_sleep_pi(struct umtx_q *uq, struct umtx_pi *pi, uint32_t owner,
1632     const char *wmesg, struct abs_timeout *timo, bool shared)
1633 {
1634 	struct umtxq_chain *uc;
1635 	struct thread *td, *td1;
1636 	struct umtx_q *uq1;
1637 	int error, pri;
1638 
1639 	error = 0;
1640 	td = uq->uq_thread;
1641 	KASSERT(td == curthread, ("inconsistent uq_thread"));
1642 	uc = umtxq_getchain(&uq->uq_key);
1643 	UMTXQ_LOCKED_ASSERT(uc);
1644 	KASSERT(uc->uc_busy != 0, ("umtx chain is not busy"));
1645 	umtxq_insert(uq);
1646 	mtx_lock(&umtx_lock);
1647 	if (pi->pi_owner == NULL) {
1648 		mtx_unlock(&umtx_lock);
1649 		td1 = tdfind(owner, shared ? -1 : td->td_proc->p_pid);
1650 		mtx_lock(&umtx_lock);
1651 		if (td1 != NULL) {
1652 			if (pi->pi_owner == NULL)
1653 				umtx_pi_setowner(pi, td1);
1654 			PROC_UNLOCK(td1->td_proc);
1655 		}
1656 	}
1657 
1658 	TAILQ_FOREACH(uq1, &pi->pi_blocked, uq_lockq) {
1659 		pri = UPRI(uq1->uq_thread);
1660 		if (pri > UPRI(td))
1661 			break;
1662 	}
1663 
1664 	if (uq1 != NULL)
1665 		TAILQ_INSERT_BEFORE(uq1, uq, uq_lockq);
1666 	else
1667 		TAILQ_INSERT_TAIL(&pi->pi_blocked, uq, uq_lockq);
1668 
1669 	uq->uq_pi_blocked = pi;
1670 	thread_lock(td);
1671 	td->td_flags |= TDF_UPIBLOCKED;
1672 	thread_unlock(td);
1673 	umtx_propagate_priority(td);
1674 	mtx_unlock(&umtx_lock);
1675 	umtxq_unbusy(&uq->uq_key);
1676 
1677 	error = umtxq_sleep(uq, wmesg, timo);
1678 	umtxq_remove(uq);
1679 
1680 	mtx_lock(&umtx_lock);
1681 	uq->uq_pi_blocked = NULL;
1682 	thread_lock(td);
1683 	td->td_flags &= ~TDF_UPIBLOCKED;
1684 	thread_unlock(td);
1685 	TAILQ_REMOVE(&pi->pi_blocked, uq, uq_lockq);
1686 	umtx_repropagate_priority(pi);
1687 	mtx_unlock(&umtx_lock);
1688 	umtxq_unlock(&uq->uq_key);
1689 
1690 	return (error);
1691 }
1692 
1693 /*
1694  * Add reference count for a PI mutex.
1695  */
1696 static void
1697 umtx_pi_ref(struct umtx_pi *pi)
1698 {
1699 	struct umtxq_chain *uc;
1700 
1701 	uc = umtxq_getchain(&pi->pi_key);
1702 	UMTXQ_LOCKED_ASSERT(uc);
1703 	pi->pi_refcount++;
1704 }
1705 
1706 /*
1707  * Decrease reference count for a PI mutex, if the counter
1708  * is decreased to zero, its memory space is freed.
1709  */
1710 static void
1711 umtx_pi_unref(struct umtx_pi *pi)
1712 {
1713 	struct umtxq_chain *uc;
1714 
1715 	uc = umtxq_getchain(&pi->pi_key);
1716 	UMTXQ_LOCKED_ASSERT(uc);
1717 	KASSERT(pi->pi_refcount > 0, ("invalid reference count"));
1718 	if (--pi->pi_refcount == 0) {
1719 		mtx_lock(&umtx_lock);
1720 		if (pi->pi_owner != NULL)
1721 			umtx_pi_disown(pi);
1722 		KASSERT(TAILQ_EMPTY(&pi->pi_blocked),
1723 			("blocked queue not empty"));
1724 		mtx_unlock(&umtx_lock);
1725 		TAILQ_REMOVE(&uc->uc_pi_list, pi, pi_hashlink);
1726 		umtx_pi_free(pi);
1727 	}
1728 }
1729 
1730 /*
1731  * Find a PI mutex in hash table.
1732  */
1733 static struct umtx_pi *
1734 umtx_pi_lookup(struct umtx_key *key)
1735 {
1736 	struct umtxq_chain *uc;
1737 	struct umtx_pi *pi;
1738 
1739 	uc = umtxq_getchain(key);
1740 	UMTXQ_LOCKED_ASSERT(uc);
1741 
1742 	TAILQ_FOREACH(pi, &uc->uc_pi_list, pi_hashlink) {
1743 		if (umtx_key_match(&pi->pi_key, key)) {
1744 			return (pi);
1745 		}
1746 	}
1747 	return (NULL);
1748 }
1749 
1750 /*
1751  * Insert a PI mutex into hash table.
1752  */
1753 static inline void
1754 umtx_pi_insert(struct umtx_pi *pi)
1755 {
1756 	struct umtxq_chain *uc;
1757 
1758 	uc = umtxq_getchain(&pi->pi_key);
1759 	UMTXQ_LOCKED_ASSERT(uc);
1760 	TAILQ_INSERT_TAIL(&uc->uc_pi_list, pi, pi_hashlink);
1761 }
1762 
1763 /*
1764  * Lock a PI mutex.
1765  */
1766 static int
1767 do_lock_pi(struct thread *td, struct umutex *m, uint32_t flags,
1768     struct _umtx_time *timeout, int try)
1769 {
1770 	struct abs_timeout timo;
1771 	struct umtx_q *uq;
1772 	struct umtx_pi *pi, *new_pi;
1773 	uint32_t id, old_owner, owner, old;
1774 	int error, rv;
1775 
1776 	id = td->td_tid;
1777 	uq = td->td_umtxq;
1778 
1779 	if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
1780 	    TYPE_PI_ROBUST_UMUTEX : TYPE_PI_UMUTEX, GET_SHARE(flags),
1781 	    &uq->uq_key)) != 0)
1782 		return (error);
1783 
1784 	if (timeout != NULL)
1785 		abs_timeout_init2(&timo, timeout);
1786 
1787 	umtxq_lock(&uq->uq_key);
1788 	pi = umtx_pi_lookup(&uq->uq_key);
1789 	if (pi == NULL) {
1790 		new_pi = umtx_pi_alloc(M_NOWAIT);
1791 		if (new_pi == NULL) {
1792 			umtxq_unlock(&uq->uq_key);
1793 			new_pi = umtx_pi_alloc(M_WAITOK);
1794 			umtxq_lock(&uq->uq_key);
1795 			pi = umtx_pi_lookup(&uq->uq_key);
1796 			if (pi != NULL) {
1797 				umtx_pi_free(new_pi);
1798 				new_pi = NULL;
1799 			}
1800 		}
1801 		if (new_pi != NULL) {
1802 			new_pi->pi_key = uq->uq_key;
1803 			umtx_pi_insert(new_pi);
1804 			pi = new_pi;
1805 		}
1806 	}
1807 	umtx_pi_ref(pi);
1808 	umtxq_unlock(&uq->uq_key);
1809 
1810 	/*
1811 	 * Care must be exercised when dealing with umtx structure.  It
1812 	 * can fault on any access.
1813 	 */
1814 	for (;;) {
1815 		/*
1816 		 * Try the uncontested case.  This should be done in userland.
1817 		 */
1818 		rv = casueword32(&m->m_owner, UMUTEX_UNOWNED, &owner, id);
1819 		/* The address was invalid. */
1820 		if (rv == -1) {
1821 			error = EFAULT;
1822 			break;
1823 		}
1824 
1825 		/* The acquire succeeded. */
1826 		if (owner == UMUTEX_UNOWNED) {
1827 			error = 0;
1828 			break;
1829 		}
1830 
1831 		if (owner == UMUTEX_RB_NOTRECOV) {
1832 			error = ENOTRECOVERABLE;
1833 			break;
1834 		}
1835 
1836 		/* If no one owns it but it is contested try to acquire it. */
1837 		if (owner == UMUTEX_CONTESTED || owner == UMUTEX_RB_OWNERDEAD) {
1838 			old_owner = owner;
1839 			rv = casueword32(&m->m_owner, owner, &owner,
1840 			    id | UMUTEX_CONTESTED);
1841 			/* The address was invalid. */
1842 			if (rv == -1) {
1843 				error = EFAULT;
1844 				break;
1845 			}
1846 
1847 			if (owner == old_owner) {
1848 				umtxq_lock(&uq->uq_key);
1849 				umtxq_busy(&uq->uq_key);
1850 				error = umtx_pi_claim(pi, td);
1851 				umtxq_unbusy(&uq->uq_key);
1852 				umtxq_unlock(&uq->uq_key);
1853 				if (error != 0) {
1854 					/*
1855 					 * Since we're going to return an
1856 					 * error, restore the m_owner to its
1857 					 * previous, unowned state to avoid
1858 					 * compounding the problem.
1859 					 */
1860 					(void)casuword32(&m->m_owner,
1861 					    id | UMUTEX_CONTESTED,
1862 					    old_owner);
1863 				}
1864 				if (error == 0 &&
1865 				    old_owner == UMUTEX_RB_OWNERDEAD)
1866 					error = EOWNERDEAD;
1867 				break;
1868 			}
1869 
1870 			error = umtxq_check_susp(td);
1871 			if (error != 0)
1872 				break;
1873 
1874 			/* If this failed the lock has changed, restart. */
1875 			continue;
1876 		}
1877 
1878 		if ((owner & ~UMUTEX_CONTESTED) == id) {
1879 			error = EDEADLK;
1880 			break;
1881 		}
1882 
1883 		if (try != 0) {
1884 			error = EBUSY;
1885 			break;
1886 		}
1887 
1888 		/*
1889 		 * If we caught a signal, we have retried and now
1890 		 * exit immediately.
1891 		 */
1892 		if (error != 0)
1893 			break;
1894 
1895 		umtxq_lock(&uq->uq_key);
1896 		umtxq_busy(&uq->uq_key);
1897 		umtxq_unlock(&uq->uq_key);
1898 
1899 		/*
1900 		 * Set the contested bit so that a release in user space
1901 		 * knows to use the system call for unlock.  If this fails
1902 		 * either some one else has acquired the lock or it has been
1903 		 * released.
1904 		 */
1905 		rv = casueword32(&m->m_owner, owner, &old, owner |
1906 		    UMUTEX_CONTESTED);
1907 
1908 		/* The address was invalid. */
1909 		if (rv == -1) {
1910 			umtxq_unbusy_unlocked(&uq->uq_key);
1911 			error = EFAULT;
1912 			break;
1913 		}
1914 
1915 		umtxq_lock(&uq->uq_key);
1916 		/*
1917 		 * We set the contested bit, sleep. Otherwise the lock changed
1918 		 * and we need to retry or we lost a race to the thread
1919 		 * unlocking the umtx.  Note that the UMUTEX_RB_OWNERDEAD
1920 		 * value for owner is impossible there.
1921 		 */
1922 		if (old == owner) {
1923 			error = umtxq_sleep_pi(uq, pi,
1924 			    owner & ~UMUTEX_CONTESTED,
1925 			    "umtxpi", timeout == NULL ? NULL : &timo,
1926 			    (flags & USYNC_PROCESS_SHARED) != 0);
1927 			if (error != 0)
1928 				continue;
1929 		} else {
1930 			umtxq_unbusy(&uq->uq_key);
1931 			umtxq_unlock(&uq->uq_key);
1932 		}
1933 
1934 		error = umtxq_check_susp(td);
1935 		if (error != 0)
1936 			break;
1937 	}
1938 
1939 	umtxq_lock(&uq->uq_key);
1940 	umtx_pi_unref(pi);
1941 	umtxq_unlock(&uq->uq_key);
1942 
1943 	umtx_key_release(&uq->uq_key);
1944 	return (error);
1945 }
1946 
1947 /*
1948  * Unlock a PI mutex.
1949  */
1950 static int
1951 do_unlock_pi(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
1952 {
1953 	struct umtx_key key;
1954 	struct umtx_q *uq_first, *uq_first2, *uq_me;
1955 	struct umtx_pi *pi, *pi2;
1956 	uint32_t id, new_owner, old, owner;
1957 	int count, error, pri;
1958 
1959 	id = td->td_tid;
1960 	/*
1961 	 * Make sure we own this mtx.
1962 	 */
1963 	error = fueword32(&m->m_owner, &owner);
1964 	if (error == -1)
1965 		return (EFAULT);
1966 
1967 	if ((owner & ~UMUTEX_CONTESTED) != id)
1968 		return (EPERM);
1969 
1970 	new_owner = umtx_unlock_val(flags, rb);
1971 
1972 	/* This should be done in userland */
1973 	if ((owner & UMUTEX_CONTESTED) == 0) {
1974 		error = casueword32(&m->m_owner, owner, &old, new_owner);
1975 		if (error == -1)
1976 			return (EFAULT);
1977 		if (old == owner)
1978 			return (0);
1979 		owner = old;
1980 	}
1981 
1982 	/* We should only ever be in here for contested locks */
1983 	if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
1984 	    TYPE_PI_ROBUST_UMUTEX : TYPE_PI_UMUTEX, GET_SHARE(flags),
1985 	    &key)) != 0)
1986 		return (error);
1987 
1988 	umtxq_lock(&key);
1989 	umtxq_busy(&key);
1990 	count = umtxq_count_pi(&key, &uq_first);
1991 	if (uq_first != NULL) {
1992 		mtx_lock(&umtx_lock);
1993 		pi = uq_first->uq_pi_blocked;
1994 		KASSERT(pi != NULL, ("pi == NULL?"));
1995 		if (pi->pi_owner != td && !(rb && pi->pi_owner == NULL)) {
1996 			mtx_unlock(&umtx_lock);
1997 			umtxq_unbusy(&key);
1998 			umtxq_unlock(&key);
1999 			umtx_key_release(&key);
2000 			/* userland messed the mutex */
2001 			return (EPERM);
2002 		}
2003 		uq_me = td->td_umtxq;
2004 		if (pi->pi_owner == td)
2005 			umtx_pi_disown(pi);
2006 		/* get highest priority thread which is still sleeping. */
2007 		uq_first = TAILQ_FIRST(&pi->pi_blocked);
2008 		while (uq_first != NULL &&
2009 		    (uq_first->uq_flags & UQF_UMTXQ) == 0) {
2010 			uq_first = TAILQ_NEXT(uq_first, uq_lockq);
2011 		}
2012 		pri = PRI_MAX;
2013 		TAILQ_FOREACH(pi2, &uq_me->uq_pi_contested, pi_link) {
2014 			uq_first2 = TAILQ_FIRST(&pi2->pi_blocked);
2015 			if (uq_first2 != NULL) {
2016 				if (pri > UPRI(uq_first2->uq_thread))
2017 					pri = UPRI(uq_first2->uq_thread);
2018 			}
2019 		}
2020 		thread_lock(td);
2021 		sched_lend_user_prio(td, pri);
2022 		thread_unlock(td);
2023 		mtx_unlock(&umtx_lock);
2024 		if (uq_first)
2025 			umtxq_signal_thread(uq_first);
2026 	} else {
2027 		pi = umtx_pi_lookup(&key);
2028 		/*
2029 		 * A umtx_pi can exist if a signal or timeout removed the
2030 		 * last waiter from the umtxq, but there is still
2031 		 * a thread in do_lock_pi() holding the umtx_pi.
2032 		 */
2033 		if (pi != NULL) {
2034 			/*
2035 			 * The umtx_pi can be unowned, such as when a thread
2036 			 * has just entered do_lock_pi(), allocated the
2037 			 * umtx_pi, and unlocked the umtxq.
2038 			 * If the current thread owns it, it must disown it.
2039 			 */
2040 			mtx_lock(&umtx_lock);
2041 			if (pi->pi_owner == td)
2042 				umtx_pi_disown(pi);
2043 			mtx_unlock(&umtx_lock);
2044 		}
2045 	}
2046 	umtxq_unlock(&key);
2047 
2048 	/*
2049 	 * When unlocking the umtx, it must be marked as unowned if
2050 	 * there is zero or one thread only waiting for it.
2051 	 * Otherwise, it must be marked as contested.
2052 	 */
2053 
2054 	if (count > 1)
2055 		new_owner |= UMUTEX_CONTESTED;
2056 	error = casueword32(&m->m_owner, owner, &old, new_owner);
2057 
2058 	umtxq_unbusy_unlocked(&key);
2059 	umtx_key_release(&key);
2060 	if (error == -1)
2061 		return (EFAULT);
2062 	if (old != owner)
2063 		return (EINVAL);
2064 	return (0);
2065 }
2066 
2067 /*
2068  * Lock a PP mutex.
2069  */
2070 static int
2071 do_lock_pp(struct thread *td, struct umutex *m, uint32_t flags,
2072     struct _umtx_time *timeout, int try)
2073 {
2074 	struct abs_timeout timo;
2075 	struct umtx_q *uq, *uq2;
2076 	struct umtx_pi *pi;
2077 	uint32_t ceiling;
2078 	uint32_t owner, id;
2079 	int error, pri, old_inherited_pri, su, rv;
2080 
2081 	id = td->td_tid;
2082 	uq = td->td_umtxq;
2083 	if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
2084 	    TYPE_PP_ROBUST_UMUTEX : TYPE_PP_UMUTEX, GET_SHARE(flags),
2085 	    &uq->uq_key)) != 0)
2086 		return (error);
2087 
2088 	if (timeout != NULL)
2089 		abs_timeout_init2(&timo, timeout);
2090 
2091 	su = (priv_check(td, PRIV_SCHED_RTPRIO) == 0);
2092 	for (;;) {
2093 		old_inherited_pri = uq->uq_inherited_pri;
2094 		umtxq_lock(&uq->uq_key);
2095 		umtxq_busy(&uq->uq_key);
2096 		umtxq_unlock(&uq->uq_key);
2097 
2098 		rv = fueword32(&m->m_ceilings[0], &ceiling);
2099 		if (rv == -1) {
2100 			error = EFAULT;
2101 			goto out;
2102 		}
2103 		ceiling = RTP_PRIO_MAX - ceiling;
2104 		if (ceiling > RTP_PRIO_MAX) {
2105 			error = EINVAL;
2106 			goto out;
2107 		}
2108 
2109 		mtx_lock(&umtx_lock);
2110 		if (UPRI(td) < PRI_MIN_REALTIME + ceiling) {
2111 			mtx_unlock(&umtx_lock);
2112 			error = EINVAL;
2113 			goto out;
2114 		}
2115 		if (su && PRI_MIN_REALTIME + ceiling < uq->uq_inherited_pri) {
2116 			uq->uq_inherited_pri = PRI_MIN_REALTIME + ceiling;
2117 			thread_lock(td);
2118 			if (uq->uq_inherited_pri < UPRI(td))
2119 				sched_lend_user_prio(td, uq->uq_inherited_pri);
2120 			thread_unlock(td);
2121 		}
2122 		mtx_unlock(&umtx_lock);
2123 
2124 		rv = casueword32(&m->m_owner, UMUTEX_CONTESTED, &owner,
2125 		    id | UMUTEX_CONTESTED);
2126 		/* The address was invalid. */
2127 		if (rv == -1) {
2128 			error = EFAULT;
2129 			break;
2130 		}
2131 
2132 		if (owner == UMUTEX_CONTESTED) {
2133 			error = 0;
2134 			break;
2135 		} else if (owner == UMUTEX_RB_OWNERDEAD) {
2136 			rv = casueword32(&m->m_owner, UMUTEX_RB_OWNERDEAD,
2137 			    &owner, id | UMUTEX_CONTESTED);
2138 			if (rv == -1) {
2139 				error = EFAULT;
2140 				break;
2141 			}
2142 			if (owner == UMUTEX_RB_OWNERDEAD) {
2143 				error = EOWNERDEAD; /* success */
2144 				break;
2145 			}
2146 			error = 0;
2147 		} else if (owner == UMUTEX_RB_NOTRECOV) {
2148 			error = ENOTRECOVERABLE;
2149 			break;
2150 		}
2151 
2152 		if (try != 0) {
2153 			error = EBUSY;
2154 			break;
2155 		}
2156 
2157 		/*
2158 		 * If we caught a signal, we have retried and now
2159 		 * exit immediately.
2160 		 */
2161 		if (error != 0)
2162 			break;
2163 
2164 		umtxq_lock(&uq->uq_key);
2165 		umtxq_insert(uq);
2166 		umtxq_unbusy(&uq->uq_key);
2167 		error = umtxq_sleep(uq, "umtxpp", timeout == NULL ?
2168 		    NULL : &timo);
2169 		umtxq_remove(uq);
2170 		umtxq_unlock(&uq->uq_key);
2171 
2172 		mtx_lock(&umtx_lock);
2173 		uq->uq_inherited_pri = old_inherited_pri;
2174 		pri = PRI_MAX;
2175 		TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
2176 			uq2 = TAILQ_FIRST(&pi->pi_blocked);
2177 			if (uq2 != NULL) {
2178 				if (pri > UPRI(uq2->uq_thread))
2179 					pri = UPRI(uq2->uq_thread);
2180 			}
2181 		}
2182 		if (pri > uq->uq_inherited_pri)
2183 			pri = uq->uq_inherited_pri;
2184 		thread_lock(td);
2185 		sched_lend_user_prio(td, pri);
2186 		thread_unlock(td);
2187 		mtx_unlock(&umtx_lock);
2188 	}
2189 
2190 	if (error != 0 && error != EOWNERDEAD) {
2191 		mtx_lock(&umtx_lock);
2192 		uq->uq_inherited_pri = old_inherited_pri;
2193 		pri = PRI_MAX;
2194 		TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
2195 			uq2 = TAILQ_FIRST(&pi->pi_blocked);
2196 			if (uq2 != NULL) {
2197 				if (pri > UPRI(uq2->uq_thread))
2198 					pri = UPRI(uq2->uq_thread);
2199 			}
2200 		}
2201 		if (pri > uq->uq_inherited_pri)
2202 			pri = uq->uq_inherited_pri;
2203 		thread_lock(td);
2204 		sched_lend_user_prio(td, pri);
2205 		thread_unlock(td);
2206 		mtx_unlock(&umtx_lock);
2207 	}
2208 
2209 out:
2210 	umtxq_unbusy_unlocked(&uq->uq_key);
2211 	umtx_key_release(&uq->uq_key);
2212 	return (error);
2213 }
2214 
2215 /*
2216  * Unlock a PP mutex.
2217  */
2218 static int
2219 do_unlock_pp(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
2220 {
2221 	struct umtx_key key;
2222 	struct umtx_q *uq, *uq2;
2223 	struct umtx_pi *pi;
2224 	uint32_t id, owner, rceiling;
2225 	int error, pri, new_inherited_pri, su;
2226 
2227 	id = td->td_tid;
2228 	uq = td->td_umtxq;
2229 	su = (priv_check(td, PRIV_SCHED_RTPRIO) == 0);
2230 
2231 	/*
2232 	 * Make sure we own this mtx.
2233 	 */
2234 	error = fueword32(&m->m_owner, &owner);
2235 	if (error == -1)
2236 		return (EFAULT);
2237 
2238 	if ((owner & ~UMUTEX_CONTESTED) != id)
2239 		return (EPERM);
2240 
2241 	error = copyin(&m->m_ceilings[1], &rceiling, sizeof(uint32_t));
2242 	if (error != 0)
2243 		return (error);
2244 
2245 	if (rceiling == -1)
2246 		new_inherited_pri = PRI_MAX;
2247 	else {
2248 		rceiling = RTP_PRIO_MAX - rceiling;
2249 		if (rceiling > RTP_PRIO_MAX)
2250 			return (EINVAL);
2251 		new_inherited_pri = PRI_MIN_REALTIME + rceiling;
2252 	}
2253 
2254 	if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
2255 	    TYPE_PP_ROBUST_UMUTEX : TYPE_PP_UMUTEX, GET_SHARE(flags),
2256 	    &key)) != 0)
2257 		return (error);
2258 	umtxq_lock(&key);
2259 	umtxq_busy(&key);
2260 	umtxq_unlock(&key);
2261 	/*
2262 	 * For priority protected mutex, always set unlocked state
2263 	 * to UMUTEX_CONTESTED, so that userland always enters kernel
2264 	 * to lock the mutex, it is necessary because thread priority
2265 	 * has to be adjusted for such mutex.
2266 	 */
2267 	error = suword32(&m->m_owner, umtx_unlock_val(flags, rb) |
2268 	    UMUTEX_CONTESTED);
2269 
2270 	umtxq_lock(&key);
2271 	if (error == 0)
2272 		umtxq_signal(&key, 1);
2273 	umtxq_unbusy(&key);
2274 	umtxq_unlock(&key);
2275 
2276 	if (error == -1)
2277 		error = EFAULT;
2278 	else {
2279 		mtx_lock(&umtx_lock);
2280 		if (su != 0)
2281 			uq->uq_inherited_pri = new_inherited_pri;
2282 		pri = PRI_MAX;
2283 		TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
2284 			uq2 = TAILQ_FIRST(&pi->pi_blocked);
2285 			if (uq2 != NULL) {
2286 				if (pri > UPRI(uq2->uq_thread))
2287 					pri = UPRI(uq2->uq_thread);
2288 			}
2289 		}
2290 		if (pri > uq->uq_inherited_pri)
2291 			pri = uq->uq_inherited_pri;
2292 		thread_lock(td);
2293 		sched_lend_user_prio(td, pri);
2294 		thread_unlock(td);
2295 		mtx_unlock(&umtx_lock);
2296 	}
2297 	umtx_key_release(&key);
2298 	return (error);
2299 }
2300 
2301 static int
2302 do_set_ceiling(struct thread *td, struct umutex *m, uint32_t ceiling,
2303     uint32_t *old_ceiling)
2304 {
2305 	struct umtx_q *uq;
2306 	uint32_t flags, id, owner, save_ceiling;
2307 	int error, rv, rv1;
2308 
2309 	error = fueword32(&m->m_flags, &flags);
2310 	if (error == -1)
2311 		return (EFAULT);
2312 	if ((flags & UMUTEX_PRIO_PROTECT) == 0)
2313 		return (EINVAL);
2314 	if (ceiling > RTP_PRIO_MAX)
2315 		return (EINVAL);
2316 	id = td->td_tid;
2317 	uq = td->td_umtxq;
2318 	if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
2319 	    TYPE_PP_ROBUST_UMUTEX : TYPE_PP_UMUTEX, GET_SHARE(flags),
2320 	    &uq->uq_key)) != 0)
2321 		return (error);
2322 	for (;;) {
2323 		umtxq_lock(&uq->uq_key);
2324 		umtxq_busy(&uq->uq_key);
2325 		umtxq_unlock(&uq->uq_key);
2326 
2327 		rv = fueword32(&m->m_ceilings[0], &save_ceiling);
2328 		if (rv == -1) {
2329 			error = EFAULT;
2330 			break;
2331 		}
2332 
2333 		rv = casueword32(&m->m_owner, UMUTEX_CONTESTED, &owner,
2334 		    id | UMUTEX_CONTESTED);
2335 		if (rv == -1) {
2336 			error = EFAULT;
2337 			break;
2338 		}
2339 
2340 		if (owner == UMUTEX_CONTESTED) {
2341 			rv = suword32(&m->m_ceilings[0], ceiling);
2342 			rv1 = suword32(&m->m_owner, UMUTEX_CONTESTED);
2343 			error = (rv == 0 && rv1 == 0) ? 0: EFAULT;
2344 			break;
2345 		}
2346 
2347 		if ((owner & ~UMUTEX_CONTESTED) == id) {
2348 			rv = suword32(&m->m_ceilings[0], ceiling);
2349 			error = rv == 0 ? 0 : EFAULT;
2350 			break;
2351 		}
2352 
2353 		if (owner == UMUTEX_RB_OWNERDEAD) {
2354 			error = EOWNERDEAD;
2355 			break;
2356 		} else if (owner == UMUTEX_RB_NOTRECOV) {
2357 			error = ENOTRECOVERABLE;
2358 			break;
2359 		}
2360 
2361 		/*
2362 		 * If we caught a signal, we have retried and now
2363 		 * exit immediately.
2364 		 */
2365 		if (error != 0)
2366 			break;
2367 
2368 		/*
2369 		 * We set the contested bit, sleep. Otherwise the lock changed
2370 		 * and we need to retry or we lost a race to the thread
2371 		 * unlocking the umtx.
2372 		 */
2373 		umtxq_lock(&uq->uq_key);
2374 		umtxq_insert(uq);
2375 		umtxq_unbusy(&uq->uq_key);
2376 		error = umtxq_sleep(uq, "umtxpp", NULL);
2377 		umtxq_remove(uq);
2378 		umtxq_unlock(&uq->uq_key);
2379 	}
2380 	umtxq_lock(&uq->uq_key);
2381 	if (error == 0)
2382 		umtxq_signal(&uq->uq_key, INT_MAX);
2383 	umtxq_unbusy(&uq->uq_key);
2384 	umtxq_unlock(&uq->uq_key);
2385 	umtx_key_release(&uq->uq_key);
2386 	if (error == 0 && old_ceiling != NULL) {
2387 		rv = suword32(old_ceiling, save_ceiling);
2388 		error = rv == 0 ? 0 : EFAULT;
2389 	}
2390 	return (error);
2391 }
2392 
2393 /*
2394  * Lock a userland POSIX mutex.
2395  */
2396 static int
2397 do_lock_umutex(struct thread *td, struct umutex *m,
2398     struct _umtx_time *timeout, int mode)
2399 {
2400 	uint32_t flags;
2401 	int error;
2402 
2403 	error = fueword32(&m->m_flags, &flags);
2404 	if (error == -1)
2405 		return (EFAULT);
2406 
2407 	switch (flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT)) {
2408 	case 0:
2409 		error = do_lock_normal(td, m, flags, timeout, mode);
2410 		break;
2411 	case UMUTEX_PRIO_INHERIT:
2412 		error = do_lock_pi(td, m, flags, timeout, mode);
2413 		break;
2414 	case UMUTEX_PRIO_PROTECT:
2415 		error = do_lock_pp(td, m, flags, timeout, mode);
2416 		break;
2417 	default:
2418 		return (EINVAL);
2419 	}
2420 	if (timeout == NULL) {
2421 		if (error == EINTR && mode != _UMUTEX_WAIT)
2422 			error = ERESTART;
2423 	} else {
2424 		/* Timed-locking is not restarted. */
2425 		if (error == ERESTART)
2426 			error = EINTR;
2427 	}
2428 	return (error);
2429 }
2430 
2431 /*
2432  * Unlock a userland POSIX mutex.
2433  */
2434 static int
2435 do_unlock_umutex(struct thread *td, struct umutex *m, bool rb)
2436 {
2437 	uint32_t flags;
2438 	int error;
2439 
2440 	error = fueword32(&m->m_flags, &flags);
2441 	if (error == -1)
2442 		return (EFAULT);
2443 
2444 	switch (flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT)) {
2445 	case 0:
2446 		return (do_unlock_normal(td, m, flags, rb));
2447 	case UMUTEX_PRIO_INHERIT:
2448 		return (do_unlock_pi(td, m, flags, rb));
2449 	case UMUTEX_PRIO_PROTECT:
2450 		return (do_unlock_pp(td, m, flags, rb));
2451 	}
2452 
2453 	return (EINVAL);
2454 }
2455 
2456 static int
2457 do_cv_wait(struct thread *td, struct ucond *cv, struct umutex *m,
2458     struct timespec *timeout, u_long wflags)
2459 {
2460 	struct abs_timeout timo;
2461 	struct umtx_q *uq;
2462 	uint32_t flags, clockid, hasw;
2463 	int error;
2464 
2465 	uq = td->td_umtxq;
2466 	error = fueword32(&cv->c_flags, &flags);
2467 	if (error == -1)
2468 		return (EFAULT);
2469 	error = umtx_key_get(cv, TYPE_CV, GET_SHARE(flags), &uq->uq_key);
2470 	if (error != 0)
2471 		return (error);
2472 
2473 	if ((wflags & CVWAIT_CLOCKID) != 0) {
2474 		error = fueword32(&cv->c_clockid, &clockid);
2475 		if (error == -1) {
2476 			umtx_key_release(&uq->uq_key);
2477 			return (EFAULT);
2478 		}
2479 		if (clockid < CLOCK_REALTIME ||
2480 		    clockid >= CLOCK_THREAD_CPUTIME_ID) {
2481 			/* hmm, only HW clock id will work. */
2482 			umtx_key_release(&uq->uq_key);
2483 			return (EINVAL);
2484 		}
2485 	} else {
2486 		clockid = CLOCK_REALTIME;
2487 	}
2488 
2489 	umtxq_lock(&uq->uq_key);
2490 	umtxq_busy(&uq->uq_key);
2491 	umtxq_insert(uq);
2492 	umtxq_unlock(&uq->uq_key);
2493 
2494 	/*
2495 	 * Set c_has_waiters to 1 before releasing user mutex, also
2496 	 * don't modify cache line when unnecessary.
2497 	 */
2498 	error = fueword32(&cv->c_has_waiters, &hasw);
2499 	if (error == 0 && hasw == 0)
2500 		suword32(&cv->c_has_waiters, 1);
2501 
2502 	umtxq_unbusy_unlocked(&uq->uq_key);
2503 
2504 	error = do_unlock_umutex(td, m, false);
2505 
2506 	if (timeout != NULL)
2507 		abs_timeout_init(&timo, clockid, (wflags & CVWAIT_ABSTIME) != 0,
2508 		    timeout);
2509 
2510 	umtxq_lock(&uq->uq_key);
2511 	if (error == 0) {
2512 		error = umtxq_sleep(uq, "ucond", timeout == NULL ?
2513 		    NULL : &timo);
2514 	}
2515 
2516 	if ((uq->uq_flags & UQF_UMTXQ) == 0)
2517 		error = 0;
2518 	else {
2519 		/*
2520 		 * This must be timeout,interrupted by signal or
2521 		 * surprious wakeup, clear c_has_waiter flag when
2522 		 * necessary.
2523 		 */
2524 		umtxq_busy(&uq->uq_key);
2525 		if ((uq->uq_flags & UQF_UMTXQ) != 0) {
2526 			int oldlen = uq->uq_cur_queue->length;
2527 			umtxq_remove(uq);
2528 			if (oldlen == 1) {
2529 				umtxq_unlock(&uq->uq_key);
2530 				suword32(&cv->c_has_waiters, 0);
2531 				umtxq_lock(&uq->uq_key);
2532 			}
2533 		}
2534 		umtxq_unbusy(&uq->uq_key);
2535 		if (error == ERESTART)
2536 			error = EINTR;
2537 	}
2538 
2539 	umtxq_unlock(&uq->uq_key);
2540 	umtx_key_release(&uq->uq_key);
2541 	return (error);
2542 }
2543 
2544 /*
2545  * Signal a userland condition variable.
2546  */
2547 static int
2548 do_cv_signal(struct thread *td, struct ucond *cv)
2549 {
2550 	struct umtx_key key;
2551 	int error, cnt, nwake;
2552 	uint32_t flags;
2553 
2554 	error = fueword32(&cv->c_flags, &flags);
2555 	if (error == -1)
2556 		return (EFAULT);
2557 	if ((error = umtx_key_get(cv, TYPE_CV, GET_SHARE(flags), &key)) != 0)
2558 		return (error);
2559 	umtxq_lock(&key);
2560 	umtxq_busy(&key);
2561 	cnt = umtxq_count(&key);
2562 	nwake = umtxq_signal(&key, 1);
2563 	if (cnt <= nwake) {
2564 		umtxq_unlock(&key);
2565 		error = suword32(&cv->c_has_waiters, 0);
2566 		if (error == -1)
2567 			error = EFAULT;
2568 		umtxq_lock(&key);
2569 	}
2570 	umtxq_unbusy(&key);
2571 	umtxq_unlock(&key);
2572 	umtx_key_release(&key);
2573 	return (error);
2574 }
2575 
2576 static int
2577 do_cv_broadcast(struct thread *td, struct ucond *cv)
2578 {
2579 	struct umtx_key key;
2580 	int error;
2581 	uint32_t flags;
2582 
2583 	error = fueword32(&cv->c_flags, &flags);
2584 	if (error == -1)
2585 		return (EFAULT);
2586 	if ((error = umtx_key_get(cv, TYPE_CV, GET_SHARE(flags), &key)) != 0)
2587 		return (error);
2588 
2589 	umtxq_lock(&key);
2590 	umtxq_busy(&key);
2591 	umtxq_signal(&key, INT_MAX);
2592 	umtxq_unlock(&key);
2593 
2594 	error = suword32(&cv->c_has_waiters, 0);
2595 	if (error == -1)
2596 		error = EFAULT;
2597 
2598 	umtxq_unbusy_unlocked(&key);
2599 
2600 	umtx_key_release(&key);
2601 	return (error);
2602 }
2603 
2604 static int
2605 do_rw_rdlock(struct thread *td, struct urwlock *rwlock, long fflag, struct _umtx_time *timeout)
2606 {
2607 	struct abs_timeout timo;
2608 	struct umtx_q *uq;
2609 	uint32_t flags, wrflags;
2610 	int32_t state, oldstate;
2611 	int32_t blocked_readers;
2612 	int error, rv;
2613 
2614 	uq = td->td_umtxq;
2615 	error = fueword32(&rwlock->rw_flags, &flags);
2616 	if (error == -1)
2617 		return (EFAULT);
2618 	error = umtx_key_get(rwlock, TYPE_RWLOCK, GET_SHARE(flags), &uq->uq_key);
2619 	if (error != 0)
2620 		return (error);
2621 
2622 	if (timeout != NULL)
2623 		abs_timeout_init2(&timo, timeout);
2624 
2625 	wrflags = URWLOCK_WRITE_OWNER;
2626 	if (!(fflag & URWLOCK_PREFER_READER) && !(flags & URWLOCK_PREFER_READER))
2627 		wrflags |= URWLOCK_WRITE_WAITERS;
2628 
2629 	for (;;) {
2630 		rv = fueword32(&rwlock->rw_state, &state);
2631 		if (rv == -1) {
2632 			umtx_key_release(&uq->uq_key);
2633 			return (EFAULT);
2634 		}
2635 
2636 		/* try to lock it */
2637 		while (!(state & wrflags)) {
2638 			if (__predict_false(URWLOCK_READER_COUNT(state) == URWLOCK_MAX_READERS)) {
2639 				umtx_key_release(&uq->uq_key);
2640 				return (EAGAIN);
2641 			}
2642 			rv = casueword32(&rwlock->rw_state, state,
2643 			    &oldstate, state + 1);
2644 			if (rv == -1) {
2645 				umtx_key_release(&uq->uq_key);
2646 				return (EFAULT);
2647 			}
2648 			if (oldstate == state) {
2649 				umtx_key_release(&uq->uq_key);
2650 				return (0);
2651 			}
2652 			error = umtxq_check_susp(td);
2653 			if (error != 0)
2654 				break;
2655 			state = oldstate;
2656 		}
2657 
2658 		if (error)
2659 			break;
2660 
2661 		/* grab monitor lock */
2662 		umtxq_lock(&uq->uq_key);
2663 		umtxq_busy(&uq->uq_key);
2664 		umtxq_unlock(&uq->uq_key);
2665 
2666 		/*
2667 		 * re-read the state, in case it changed between the try-lock above
2668 		 * and the check below
2669 		 */
2670 		rv = fueword32(&rwlock->rw_state, &state);
2671 		if (rv == -1)
2672 			error = EFAULT;
2673 
2674 		/* set read contention bit */
2675 		while (error == 0 && (state & wrflags) &&
2676 		    !(state & URWLOCK_READ_WAITERS)) {
2677 			rv = casueword32(&rwlock->rw_state, state,
2678 			    &oldstate, state | URWLOCK_READ_WAITERS);
2679 			if (rv == -1) {
2680 				error = EFAULT;
2681 				break;
2682 			}
2683 			if (oldstate == state)
2684 				goto sleep;
2685 			state = oldstate;
2686 			error = umtxq_check_susp(td);
2687 			if (error != 0)
2688 				break;
2689 		}
2690 		if (error != 0) {
2691 			umtxq_unbusy_unlocked(&uq->uq_key);
2692 			break;
2693 		}
2694 
2695 		/* state is changed while setting flags, restart */
2696 		if (!(state & wrflags)) {
2697 			umtxq_unbusy_unlocked(&uq->uq_key);
2698 			error = umtxq_check_susp(td);
2699 			if (error != 0)
2700 				break;
2701 			continue;
2702 		}
2703 
2704 sleep:
2705 		/* contention bit is set, before sleeping, increase read waiter count */
2706 		rv = fueword32(&rwlock->rw_blocked_readers,
2707 		    &blocked_readers);
2708 		if (rv == -1) {
2709 			umtxq_unbusy_unlocked(&uq->uq_key);
2710 			error = EFAULT;
2711 			break;
2712 		}
2713 		suword32(&rwlock->rw_blocked_readers, blocked_readers+1);
2714 
2715 		while (state & wrflags) {
2716 			umtxq_lock(&uq->uq_key);
2717 			umtxq_insert(uq);
2718 			umtxq_unbusy(&uq->uq_key);
2719 
2720 			error = umtxq_sleep(uq, "urdlck", timeout == NULL ?
2721 			    NULL : &timo);
2722 
2723 			umtxq_busy(&uq->uq_key);
2724 			umtxq_remove(uq);
2725 			umtxq_unlock(&uq->uq_key);
2726 			if (error)
2727 				break;
2728 			rv = fueword32(&rwlock->rw_state, &state);
2729 			if (rv == -1) {
2730 				error = EFAULT;
2731 				break;
2732 			}
2733 		}
2734 
2735 		/* decrease read waiter count, and may clear read contention bit */
2736 		rv = fueword32(&rwlock->rw_blocked_readers,
2737 		    &blocked_readers);
2738 		if (rv == -1) {
2739 			umtxq_unbusy_unlocked(&uq->uq_key);
2740 			error = EFAULT;
2741 			break;
2742 		}
2743 		suword32(&rwlock->rw_blocked_readers, blocked_readers-1);
2744 		if (blocked_readers == 1) {
2745 			rv = fueword32(&rwlock->rw_state, &state);
2746 			if (rv == -1)
2747 				error = EFAULT;
2748 			while (error == 0) {
2749 				rv = casueword32(&rwlock->rw_state, state,
2750 				    &oldstate, state & ~URWLOCK_READ_WAITERS);
2751 				if (rv == -1) {
2752 					error = EFAULT;
2753 					break;
2754 				}
2755 				if (oldstate == state)
2756 					break;
2757 				state = oldstate;
2758 				error = umtxq_check_susp(td);
2759 			}
2760 		}
2761 
2762 		umtxq_unbusy_unlocked(&uq->uq_key);
2763 		if (error != 0)
2764 			break;
2765 	}
2766 	umtx_key_release(&uq->uq_key);
2767 	if (error == ERESTART)
2768 		error = EINTR;
2769 	return (error);
2770 }
2771 
2772 static int
2773 do_rw_wrlock(struct thread *td, struct urwlock *rwlock, struct _umtx_time *timeout)
2774 {
2775 	struct abs_timeout timo;
2776 	struct umtx_q *uq;
2777 	uint32_t flags;
2778 	int32_t state, oldstate;
2779 	int32_t blocked_writers;
2780 	int32_t blocked_readers;
2781 	int error, rv;
2782 
2783 	uq = td->td_umtxq;
2784 	error = fueword32(&rwlock->rw_flags, &flags);
2785 	if (error == -1)
2786 		return (EFAULT);
2787 	error = umtx_key_get(rwlock, TYPE_RWLOCK, GET_SHARE(flags), &uq->uq_key);
2788 	if (error != 0)
2789 		return (error);
2790 
2791 	if (timeout != NULL)
2792 		abs_timeout_init2(&timo, timeout);
2793 
2794 	blocked_readers = 0;
2795 	for (;;) {
2796 		rv = fueword32(&rwlock->rw_state, &state);
2797 		if (rv == -1) {
2798 			umtx_key_release(&uq->uq_key);
2799 			return (EFAULT);
2800 		}
2801 		while (!(state & URWLOCK_WRITE_OWNER) && URWLOCK_READER_COUNT(state) == 0) {
2802 			rv = casueword32(&rwlock->rw_state, state,
2803 			    &oldstate, state | URWLOCK_WRITE_OWNER);
2804 			if (rv == -1) {
2805 				umtx_key_release(&uq->uq_key);
2806 				return (EFAULT);
2807 			}
2808 			if (oldstate == state) {
2809 				umtx_key_release(&uq->uq_key);
2810 				return (0);
2811 			}
2812 			state = oldstate;
2813 			error = umtxq_check_susp(td);
2814 			if (error != 0)
2815 				break;
2816 		}
2817 
2818 		if (error) {
2819 			if (!(state & (URWLOCK_WRITE_OWNER|URWLOCK_WRITE_WAITERS)) &&
2820 			    blocked_readers != 0) {
2821 				umtxq_lock(&uq->uq_key);
2822 				umtxq_busy(&uq->uq_key);
2823 				umtxq_signal_queue(&uq->uq_key, INT_MAX, UMTX_SHARED_QUEUE);
2824 				umtxq_unbusy(&uq->uq_key);
2825 				umtxq_unlock(&uq->uq_key);
2826 			}
2827 
2828 			break;
2829 		}
2830 
2831 		/* grab monitor lock */
2832 		umtxq_lock(&uq->uq_key);
2833 		umtxq_busy(&uq->uq_key);
2834 		umtxq_unlock(&uq->uq_key);
2835 
2836 		/*
2837 		 * re-read the state, in case it changed between the try-lock above
2838 		 * and the check below
2839 		 */
2840 		rv = fueword32(&rwlock->rw_state, &state);
2841 		if (rv == -1)
2842 			error = EFAULT;
2843 
2844 		while (error == 0 && ((state & URWLOCK_WRITE_OWNER) ||
2845 		    URWLOCK_READER_COUNT(state) != 0) &&
2846 		    (state & URWLOCK_WRITE_WAITERS) == 0) {
2847 			rv = casueword32(&rwlock->rw_state, state,
2848 			    &oldstate, state | URWLOCK_WRITE_WAITERS);
2849 			if (rv == -1) {
2850 				error = EFAULT;
2851 				break;
2852 			}
2853 			if (oldstate == state)
2854 				goto sleep;
2855 			state = oldstate;
2856 			error = umtxq_check_susp(td);
2857 			if (error != 0)
2858 				break;
2859 		}
2860 		if (error != 0) {
2861 			umtxq_unbusy_unlocked(&uq->uq_key);
2862 			break;
2863 		}
2864 
2865 		if (!(state & URWLOCK_WRITE_OWNER) && URWLOCK_READER_COUNT(state) == 0) {
2866 			umtxq_unbusy_unlocked(&uq->uq_key);
2867 			error = umtxq_check_susp(td);
2868 			if (error != 0)
2869 				break;
2870 			continue;
2871 		}
2872 sleep:
2873 		rv = fueword32(&rwlock->rw_blocked_writers,
2874 		    &blocked_writers);
2875 		if (rv == -1) {
2876 			umtxq_unbusy_unlocked(&uq->uq_key);
2877 			error = EFAULT;
2878 			break;
2879 		}
2880 		suword32(&rwlock->rw_blocked_writers, blocked_writers+1);
2881 
2882 		while ((state & URWLOCK_WRITE_OWNER) || URWLOCK_READER_COUNT(state) != 0) {
2883 			umtxq_lock(&uq->uq_key);
2884 			umtxq_insert_queue(uq, UMTX_EXCLUSIVE_QUEUE);
2885 			umtxq_unbusy(&uq->uq_key);
2886 
2887 			error = umtxq_sleep(uq, "uwrlck", timeout == NULL ?
2888 			    NULL : &timo);
2889 
2890 			umtxq_busy(&uq->uq_key);
2891 			umtxq_remove_queue(uq, UMTX_EXCLUSIVE_QUEUE);
2892 			umtxq_unlock(&uq->uq_key);
2893 			if (error)
2894 				break;
2895 			rv = fueword32(&rwlock->rw_state, &state);
2896 			if (rv == -1) {
2897 				error = EFAULT;
2898 				break;
2899 			}
2900 		}
2901 
2902 		rv = fueword32(&rwlock->rw_blocked_writers,
2903 		    &blocked_writers);
2904 		if (rv == -1) {
2905 			umtxq_unbusy_unlocked(&uq->uq_key);
2906 			error = EFAULT;
2907 			break;
2908 		}
2909 		suword32(&rwlock->rw_blocked_writers, blocked_writers-1);
2910 		if (blocked_writers == 1) {
2911 			rv = fueword32(&rwlock->rw_state, &state);
2912 			if (rv == -1) {
2913 				umtxq_unbusy_unlocked(&uq->uq_key);
2914 				error = EFAULT;
2915 				break;
2916 			}
2917 			for (;;) {
2918 				rv = casueword32(&rwlock->rw_state, state,
2919 				    &oldstate, state & ~URWLOCK_WRITE_WAITERS);
2920 				if (rv == -1) {
2921 					error = EFAULT;
2922 					break;
2923 				}
2924 				if (oldstate == state)
2925 					break;
2926 				state = oldstate;
2927 				error = umtxq_check_susp(td);
2928 				/*
2929 				 * We are leaving the URWLOCK_WRITE_WAITERS
2930 				 * behind, but this should not harm the
2931 				 * correctness.
2932 				 */
2933 				if (error != 0)
2934 					break;
2935 			}
2936 			rv = fueword32(&rwlock->rw_blocked_readers,
2937 			    &blocked_readers);
2938 			if (rv == -1) {
2939 				umtxq_unbusy_unlocked(&uq->uq_key);
2940 				error = EFAULT;
2941 				break;
2942 			}
2943 		} else
2944 			blocked_readers = 0;
2945 
2946 		umtxq_unbusy_unlocked(&uq->uq_key);
2947 	}
2948 
2949 	umtx_key_release(&uq->uq_key);
2950 	if (error == ERESTART)
2951 		error = EINTR;
2952 	return (error);
2953 }
2954 
2955 static int
2956 do_rw_unlock(struct thread *td, struct urwlock *rwlock)
2957 {
2958 	struct umtx_q *uq;
2959 	uint32_t flags;
2960 	int32_t state, oldstate;
2961 	int error, rv, q, count;
2962 
2963 	uq = td->td_umtxq;
2964 	error = fueword32(&rwlock->rw_flags, &flags);
2965 	if (error == -1)
2966 		return (EFAULT);
2967 	error = umtx_key_get(rwlock, TYPE_RWLOCK, GET_SHARE(flags), &uq->uq_key);
2968 	if (error != 0)
2969 		return (error);
2970 
2971 	error = fueword32(&rwlock->rw_state, &state);
2972 	if (error == -1) {
2973 		error = EFAULT;
2974 		goto out;
2975 	}
2976 	if (state & URWLOCK_WRITE_OWNER) {
2977 		for (;;) {
2978 			rv = casueword32(&rwlock->rw_state, state,
2979 			    &oldstate, state & ~URWLOCK_WRITE_OWNER);
2980 			if (rv == -1) {
2981 				error = EFAULT;
2982 				goto out;
2983 			}
2984 			if (oldstate != state) {
2985 				state = oldstate;
2986 				if (!(oldstate & URWLOCK_WRITE_OWNER)) {
2987 					error = EPERM;
2988 					goto out;
2989 				}
2990 				error = umtxq_check_susp(td);
2991 				if (error != 0)
2992 					goto out;
2993 			} else
2994 				break;
2995 		}
2996 	} else if (URWLOCK_READER_COUNT(state) != 0) {
2997 		for (;;) {
2998 			rv = casueword32(&rwlock->rw_state, state,
2999 			    &oldstate, state - 1);
3000 			if (rv == -1) {
3001 				error = EFAULT;
3002 				goto out;
3003 			}
3004 			if (oldstate != state) {
3005 				state = oldstate;
3006 				if (URWLOCK_READER_COUNT(oldstate) == 0) {
3007 					error = EPERM;
3008 					goto out;
3009 				}
3010 				error = umtxq_check_susp(td);
3011 				if (error != 0)
3012 					goto out;
3013 			} else
3014 				break;
3015 		}
3016 	} else {
3017 		error = EPERM;
3018 		goto out;
3019 	}
3020 
3021 	count = 0;
3022 
3023 	if (!(flags & URWLOCK_PREFER_READER)) {
3024 		if (state & URWLOCK_WRITE_WAITERS) {
3025 			count = 1;
3026 			q = UMTX_EXCLUSIVE_QUEUE;
3027 		} else if (state & URWLOCK_READ_WAITERS) {
3028 			count = INT_MAX;
3029 			q = UMTX_SHARED_QUEUE;
3030 		}
3031 	} else {
3032 		if (state & URWLOCK_READ_WAITERS) {
3033 			count = INT_MAX;
3034 			q = UMTX_SHARED_QUEUE;
3035 		} else if (state & URWLOCK_WRITE_WAITERS) {
3036 			count = 1;
3037 			q = UMTX_EXCLUSIVE_QUEUE;
3038 		}
3039 	}
3040 
3041 	if (count) {
3042 		umtxq_lock(&uq->uq_key);
3043 		umtxq_busy(&uq->uq_key);
3044 		umtxq_signal_queue(&uq->uq_key, count, q);
3045 		umtxq_unbusy(&uq->uq_key);
3046 		umtxq_unlock(&uq->uq_key);
3047 	}
3048 out:
3049 	umtx_key_release(&uq->uq_key);
3050 	return (error);
3051 }
3052 
3053 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
3054 static int
3055 do_sem_wait(struct thread *td, struct _usem *sem, struct _umtx_time *timeout)
3056 {
3057 	struct abs_timeout timo;
3058 	struct umtx_q *uq;
3059 	uint32_t flags, count, count1;
3060 	int error, rv;
3061 
3062 	uq = td->td_umtxq;
3063 	error = fueword32(&sem->_flags, &flags);
3064 	if (error == -1)
3065 		return (EFAULT);
3066 	error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &uq->uq_key);
3067 	if (error != 0)
3068 		return (error);
3069 
3070 	if (timeout != NULL)
3071 		abs_timeout_init2(&timo, timeout);
3072 
3073 	umtxq_lock(&uq->uq_key);
3074 	umtxq_busy(&uq->uq_key);
3075 	umtxq_insert(uq);
3076 	umtxq_unlock(&uq->uq_key);
3077 	rv = casueword32(&sem->_has_waiters, 0, &count1, 1);
3078 	if (rv == 0)
3079 		rv = fueword32(&sem->_count, &count);
3080 	if (rv == -1 || count != 0) {
3081 		umtxq_lock(&uq->uq_key);
3082 		umtxq_unbusy(&uq->uq_key);
3083 		umtxq_remove(uq);
3084 		umtxq_unlock(&uq->uq_key);
3085 		umtx_key_release(&uq->uq_key);
3086 		return (rv == -1 ? EFAULT : 0);
3087 	}
3088 	umtxq_lock(&uq->uq_key);
3089 	umtxq_unbusy(&uq->uq_key);
3090 
3091 	error = umtxq_sleep(uq, "usem", timeout == NULL ? NULL : &timo);
3092 
3093 	if ((uq->uq_flags & UQF_UMTXQ) == 0)
3094 		error = 0;
3095 	else {
3096 		umtxq_remove(uq);
3097 		/* A relative timeout cannot be restarted. */
3098 		if (error == ERESTART && timeout != NULL &&
3099 		    (timeout->_flags & UMTX_ABSTIME) == 0)
3100 			error = EINTR;
3101 	}
3102 	umtxq_unlock(&uq->uq_key);
3103 	umtx_key_release(&uq->uq_key);
3104 	return (error);
3105 }
3106 
3107 /*
3108  * Signal a userland semaphore.
3109  */
3110 static int
3111 do_sem_wake(struct thread *td, struct _usem *sem)
3112 {
3113 	struct umtx_key key;
3114 	int error, cnt;
3115 	uint32_t flags;
3116 
3117 	error = fueword32(&sem->_flags, &flags);
3118 	if (error == -1)
3119 		return (EFAULT);
3120 	if ((error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &key)) != 0)
3121 		return (error);
3122 	umtxq_lock(&key);
3123 	umtxq_busy(&key);
3124 	cnt = umtxq_count(&key);
3125 	if (cnt > 0) {
3126 		umtxq_signal(&key, 1);
3127 		/*
3128 		 * Check if count is greater than 0, this means the memory is
3129 		 * still being referenced by user code, so we can safely
3130 		 * update _has_waiters flag.
3131 		 */
3132 		if (cnt == 1) {
3133 			umtxq_unlock(&key);
3134 			error = suword32(&sem->_has_waiters, 0);
3135 			umtxq_lock(&key);
3136 			if (error == -1)
3137 				error = EFAULT;
3138 		}
3139 	}
3140 	umtxq_unbusy(&key);
3141 	umtxq_unlock(&key);
3142 	umtx_key_release(&key);
3143 	return (error);
3144 }
3145 #endif
3146 
3147 static int
3148 do_sem2_wait(struct thread *td, struct _usem2 *sem, struct _umtx_time *timeout)
3149 {
3150 	struct abs_timeout timo;
3151 	struct umtx_q *uq;
3152 	uint32_t count, flags;
3153 	int error, rv;
3154 
3155 	uq = td->td_umtxq;
3156 	flags = fuword32(&sem->_flags);
3157 	error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &uq->uq_key);
3158 	if (error != 0)
3159 		return (error);
3160 
3161 	if (timeout != NULL)
3162 		abs_timeout_init2(&timo, timeout);
3163 
3164 	umtxq_lock(&uq->uq_key);
3165 	umtxq_busy(&uq->uq_key);
3166 	umtxq_insert(uq);
3167 	umtxq_unlock(&uq->uq_key);
3168 	rv = fueword32(&sem->_count, &count);
3169 	if (rv == -1) {
3170 		umtxq_lock(&uq->uq_key);
3171 		umtxq_unbusy(&uq->uq_key);
3172 		umtxq_remove(uq);
3173 		umtxq_unlock(&uq->uq_key);
3174 		umtx_key_release(&uq->uq_key);
3175 		return (EFAULT);
3176 	}
3177 	for (;;) {
3178 		if (USEM_COUNT(count) != 0) {
3179 			umtxq_lock(&uq->uq_key);
3180 			umtxq_unbusy(&uq->uq_key);
3181 			umtxq_remove(uq);
3182 			umtxq_unlock(&uq->uq_key);
3183 			umtx_key_release(&uq->uq_key);
3184 			return (0);
3185 		}
3186 		if (count == USEM_HAS_WAITERS)
3187 			break;
3188 		rv = casueword32(&sem->_count, 0, &count, USEM_HAS_WAITERS);
3189 		if (rv == -1) {
3190 			umtxq_lock(&uq->uq_key);
3191 			umtxq_unbusy(&uq->uq_key);
3192 			umtxq_remove(uq);
3193 			umtxq_unlock(&uq->uq_key);
3194 			umtx_key_release(&uq->uq_key);
3195 			return (EFAULT);
3196 		}
3197 		if (count == 0)
3198 			break;
3199 	}
3200 	umtxq_lock(&uq->uq_key);
3201 	umtxq_unbusy(&uq->uq_key);
3202 
3203 	error = umtxq_sleep(uq, "usem", timeout == NULL ? NULL : &timo);
3204 
3205 	if ((uq->uq_flags & UQF_UMTXQ) == 0)
3206 		error = 0;
3207 	else {
3208 		umtxq_remove(uq);
3209 		/* A relative timeout cannot be restarted. */
3210 		if (error == ERESTART && timeout != NULL &&
3211 		    (timeout->_flags & UMTX_ABSTIME) == 0)
3212 			error = EINTR;
3213 	}
3214 	umtxq_unlock(&uq->uq_key);
3215 	umtx_key_release(&uq->uq_key);
3216 	return (error);
3217 }
3218 
3219 /*
3220  * Signal a userland semaphore.
3221  */
3222 static int
3223 do_sem2_wake(struct thread *td, struct _usem2 *sem)
3224 {
3225 	struct umtx_key key;
3226 	int error, cnt, rv;
3227 	uint32_t count, flags;
3228 
3229 	rv = fueword32(&sem->_flags, &flags);
3230 	if (rv == -1)
3231 		return (EFAULT);
3232 	if ((error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &key)) != 0)
3233 		return (error);
3234 	umtxq_lock(&key);
3235 	umtxq_busy(&key);
3236 	cnt = umtxq_count(&key);
3237 	if (cnt > 0) {
3238 		umtxq_signal(&key, 1);
3239 
3240 		/*
3241 		 * If this was the last sleeping thread, clear the waiters
3242 		 * flag in _count.
3243 		 */
3244 		if (cnt == 1) {
3245 			umtxq_unlock(&key);
3246 			rv = fueword32(&sem->_count, &count);
3247 			while (rv != -1 && count & USEM_HAS_WAITERS)
3248 				rv = casueword32(&sem->_count, count, &count,
3249 				    count & ~USEM_HAS_WAITERS);
3250 			if (rv == -1)
3251 				error = EFAULT;
3252 			umtxq_lock(&key);
3253 		}
3254 	}
3255 	umtxq_unbusy(&key);
3256 	umtxq_unlock(&key);
3257 	umtx_key_release(&key);
3258 	return (error);
3259 }
3260 
3261 inline int
3262 umtx_copyin_timeout(const void *addr, struct timespec *tsp)
3263 {
3264 	int error;
3265 
3266 	error = copyin(addr, tsp, sizeof(struct timespec));
3267 	if (error == 0) {
3268 		if (tsp->tv_sec < 0 ||
3269 		    tsp->tv_nsec >= 1000000000 ||
3270 		    tsp->tv_nsec < 0)
3271 			error = EINVAL;
3272 	}
3273 	return (error);
3274 }
3275 
3276 static inline int
3277 umtx_copyin_umtx_time(const void *addr, size_t size, struct _umtx_time *tp)
3278 {
3279 	int error;
3280 
3281 	if (size <= sizeof(struct timespec)) {
3282 		tp->_clockid = CLOCK_REALTIME;
3283 		tp->_flags = 0;
3284 		error = copyin(addr, &tp->_timeout, sizeof(struct timespec));
3285 	} else
3286 		error = copyin(addr, tp, sizeof(struct _umtx_time));
3287 	if (error != 0)
3288 		return (error);
3289 	if (tp->_timeout.tv_sec < 0 ||
3290 	    tp->_timeout.tv_nsec >= 1000000000 || tp->_timeout.tv_nsec < 0)
3291 		return (EINVAL);
3292 	return (0);
3293 }
3294 
3295 static int
3296 __umtx_op_unimpl(struct thread *td, struct _umtx_op_args *uap)
3297 {
3298 
3299 	return (EOPNOTSUPP);
3300 }
3301 
3302 static int
3303 __umtx_op_wait(struct thread *td, struct _umtx_op_args *uap)
3304 {
3305 	struct _umtx_time timeout, *tm_p;
3306 	int error;
3307 
3308 	if (uap->uaddr2 == NULL)
3309 		tm_p = NULL;
3310 	else {
3311 		error = umtx_copyin_umtx_time(
3312 		    uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3313 		if (error != 0)
3314 			return (error);
3315 		tm_p = &timeout;
3316 	}
3317 	return (do_wait(td, uap->obj, uap->val, tm_p, 0, 0));
3318 }
3319 
3320 static int
3321 __umtx_op_wait_uint(struct thread *td, struct _umtx_op_args *uap)
3322 {
3323 	struct _umtx_time timeout, *tm_p;
3324 	int error;
3325 
3326 	if (uap->uaddr2 == NULL)
3327 		tm_p = NULL;
3328 	else {
3329 		error = umtx_copyin_umtx_time(
3330 		    uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3331 		if (error != 0)
3332 			return (error);
3333 		tm_p = &timeout;
3334 	}
3335 	return (do_wait(td, uap->obj, uap->val, tm_p, 1, 0));
3336 }
3337 
3338 static int
3339 __umtx_op_wait_uint_private(struct thread *td, struct _umtx_op_args *uap)
3340 {
3341 	struct _umtx_time *tm_p, timeout;
3342 	int error;
3343 
3344 	if (uap->uaddr2 == NULL)
3345 		tm_p = NULL;
3346 	else {
3347 		error = umtx_copyin_umtx_time(
3348 		    uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3349 		if (error != 0)
3350 			return (error);
3351 		tm_p = &timeout;
3352 	}
3353 	return (do_wait(td, uap->obj, uap->val, tm_p, 1, 1));
3354 }
3355 
3356 static int
3357 __umtx_op_wake(struct thread *td, struct _umtx_op_args *uap)
3358 {
3359 
3360 	return (kern_umtx_wake(td, uap->obj, uap->val, 0));
3361 }
3362 
3363 #define BATCH_SIZE	128
3364 static int
3365 __umtx_op_nwake_private(struct thread *td, struct _umtx_op_args *uap)
3366 {
3367 	char *uaddrs[BATCH_SIZE], **upp;
3368 	int count, error, i, pos, tocopy;
3369 
3370 	upp = (char **)uap->obj;
3371 	error = 0;
3372 	for (count = uap->val, pos = 0; count > 0; count -= tocopy,
3373 	    pos += tocopy) {
3374 		tocopy = MIN(count, BATCH_SIZE);
3375 		error = copyin(upp + pos, uaddrs, tocopy * sizeof(char *));
3376 		if (error != 0)
3377 			break;
3378 		for (i = 0; i < tocopy; ++i)
3379 			kern_umtx_wake(td, uaddrs[i], INT_MAX, 1);
3380 		maybe_yield();
3381 	}
3382 	return (error);
3383 }
3384 
3385 static int
3386 __umtx_op_wake_private(struct thread *td, struct _umtx_op_args *uap)
3387 {
3388 
3389 	return (kern_umtx_wake(td, uap->obj, uap->val, 1));
3390 }
3391 
3392 static int
3393 __umtx_op_lock_umutex(struct thread *td, struct _umtx_op_args *uap)
3394 {
3395 	struct _umtx_time *tm_p, timeout;
3396 	int error;
3397 
3398 	/* Allow a null timespec (wait forever). */
3399 	if (uap->uaddr2 == NULL)
3400 		tm_p = NULL;
3401 	else {
3402 		error = umtx_copyin_umtx_time(
3403 		    uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3404 		if (error != 0)
3405 			return (error);
3406 		tm_p = &timeout;
3407 	}
3408 	return (do_lock_umutex(td, uap->obj, tm_p, 0));
3409 }
3410 
3411 static int
3412 __umtx_op_trylock_umutex(struct thread *td, struct _umtx_op_args *uap)
3413 {
3414 
3415 	return (do_lock_umutex(td, uap->obj, NULL, _UMUTEX_TRY));
3416 }
3417 
3418 static int
3419 __umtx_op_wait_umutex(struct thread *td, struct _umtx_op_args *uap)
3420 {
3421 	struct _umtx_time *tm_p, timeout;
3422 	int error;
3423 
3424 	/* Allow a null timespec (wait forever). */
3425 	if (uap->uaddr2 == NULL)
3426 		tm_p = NULL;
3427 	else {
3428 		error = umtx_copyin_umtx_time(
3429 		    uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3430 		if (error != 0)
3431 			return (error);
3432 		tm_p = &timeout;
3433 	}
3434 	return (do_lock_umutex(td, uap->obj, tm_p, _UMUTEX_WAIT));
3435 }
3436 
3437 static int
3438 __umtx_op_wake_umutex(struct thread *td, struct _umtx_op_args *uap)
3439 {
3440 
3441 	return (do_wake_umutex(td, uap->obj));
3442 }
3443 
3444 static int
3445 __umtx_op_unlock_umutex(struct thread *td, struct _umtx_op_args *uap)
3446 {
3447 
3448 	return (do_unlock_umutex(td, uap->obj, false));
3449 }
3450 
3451 static int
3452 __umtx_op_set_ceiling(struct thread *td, struct _umtx_op_args *uap)
3453 {
3454 
3455 	return (do_set_ceiling(td, uap->obj, uap->val, uap->uaddr1));
3456 }
3457 
3458 static int
3459 __umtx_op_cv_wait(struct thread *td, struct _umtx_op_args *uap)
3460 {
3461 	struct timespec *ts, timeout;
3462 	int error;
3463 
3464 	/* Allow a null timespec (wait forever). */
3465 	if (uap->uaddr2 == NULL)
3466 		ts = NULL;
3467 	else {
3468 		error = umtx_copyin_timeout(uap->uaddr2, &timeout);
3469 		if (error != 0)
3470 			return (error);
3471 		ts = &timeout;
3472 	}
3473 	return (do_cv_wait(td, uap->obj, uap->uaddr1, ts, uap->val));
3474 }
3475 
3476 static int
3477 __umtx_op_cv_signal(struct thread *td, struct _umtx_op_args *uap)
3478 {
3479 
3480 	return (do_cv_signal(td, uap->obj));
3481 }
3482 
3483 static int
3484 __umtx_op_cv_broadcast(struct thread *td, struct _umtx_op_args *uap)
3485 {
3486 
3487 	return (do_cv_broadcast(td, uap->obj));
3488 }
3489 
3490 static int
3491 __umtx_op_rw_rdlock(struct thread *td, struct _umtx_op_args *uap)
3492 {
3493 	struct _umtx_time timeout;
3494 	int error;
3495 
3496 	/* Allow a null timespec (wait forever). */
3497 	if (uap->uaddr2 == NULL) {
3498 		error = do_rw_rdlock(td, uap->obj, uap->val, 0);
3499 	} else {
3500 		error = umtx_copyin_umtx_time(uap->uaddr2,
3501 		   (size_t)uap->uaddr1, &timeout);
3502 		if (error != 0)
3503 			return (error);
3504 		error = do_rw_rdlock(td, uap->obj, uap->val, &timeout);
3505 	}
3506 	return (error);
3507 }
3508 
3509 static int
3510 __umtx_op_rw_wrlock(struct thread *td, struct _umtx_op_args *uap)
3511 {
3512 	struct _umtx_time timeout;
3513 	int error;
3514 
3515 	/* Allow a null timespec (wait forever). */
3516 	if (uap->uaddr2 == NULL) {
3517 		error = do_rw_wrlock(td, uap->obj, 0);
3518 	} else {
3519 		error = umtx_copyin_umtx_time(uap->uaddr2,
3520 		   (size_t)uap->uaddr1, &timeout);
3521 		if (error != 0)
3522 			return (error);
3523 
3524 		error = do_rw_wrlock(td, uap->obj, &timeout);
3525 	}
3526 	return (error);
3527 }
3528 
3529 static int
3530 __umtx_op_rw_unlock(struct thread *td, struct _umtx_op_args *uap)
3531 {
3532 
3533 	return (do_rw_unlock(td, uap->obj));
3534 }
3535 
3536 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
3537 static int
3538 __umtx_op_sem_wait(struct thread *td, struct _umtx_op_args *uap)
3539 {
3540 	struct _umtx_time *tm_p, timeout;
3541 	int error;
3542 
3543 	/* Allow a null timespec (wait forever). */
3544 	if (uap->uaddr2 == NULL)
3545 		tm_p = NULL;
3546 	else {
3547 		error = umtx_copyin_umtx_time(
3548 		    uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3549 		if (error != 0)
3550 			return (error);
3551 		tm_p = &timeout;
3552 	}
3553 	return (do_sem_wait(td, uap->obj, tm_p));
3554 }
3555 
3556 static int
3557 __umtx_op_sem_wake(struct thread *td, struct _umtx_op_args *uap)
3558 {
3559 
3560 	return (do_sem_wake(td, uap->obj));
3561 }
3562 #endif
3563 
3564 static int
3565 __umtx_op_wake2_umutex(struct thread *td, struct _umtx_op_args *uap)
3566 {
3567 
3568 	return (do_wake2_umutex(td, uap->obj, uap->val));
3569 }
3570 
3571 static int
3572 __umtx_op_sem2_wait(struct thread *td, struct _umtx_op_args *uap)
3573 {
3574 	struct _umtx_time *tm_p, timeout;
3575 	int error;
3576 
3577 	/* Allow a null timespec (wait forever). */
3578 	if (uap->uaddr2 == NULL)
3579 		tm_p = NULL;
3580 	else {
3581 		error = umtx_copyin_umtx_time(
3582 		    uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3583 		if (error != 0)
3584 			return (error);
3585 		tm_p = &timeout;
3586 	}
3587 	return (do_sem2_wait(td, uap->obj, tm_p));
3588 }
3589 
3590 static int
3591 __umtx_op_sem2_wake(struct thread *td, struct _umtx_op_args *uap)
3592 {
3593 
3594 	return (do_sem2_wake(td, uap->obj));
3595 }
3596 
3597 #define	USHM_OBJ_UMTX(o)						\
3598     ((struct umtx_shm_obj_list *)(&(o)->umtx_data))
3599 
3600 #define	USHMF_REG_LINKED	0x0001
3601 #define	USHMF_OBJ_LINKED	0x0002
3602 struct umtx_shm_reg {
3603 	TAILQ_ENTRY(umtx_shm_reg) ushm_reg_link;
3604 	LIST_ENTRY(umtx_shm_reg) ushm_obj_link;
3605 	struct umtx_key		ushm_key;
3606 	struct ucred		*ushm_cred;
3607 	struct shmfd		*ushm_obj;
3608 	u_int			ushm_refcnt;
3609 	u_int			ushm_flags;
3610 };
3611 
3612 LIST_HEAD(umtx_shm_obj_list, umtx_shm_reg);
3613 TAILQ_HEAD(umtx_shm_reg_head, umtx_shm_reg);
3614 
3615 static uma_zone_t umtx_shm_reg_zone;
3616 static struct umtx_shm_reg_head umtx_shm_registry[UMTX_CHAINS];
3617 static struct mtx umtx_shm_lock;
3618 static struct umtx_shm_reg_head umtx_shm_reg_delfree =
3619     TAILQ_HEAD_INITIALIZER(umtx_shm_reg_delfree);
3620 
3621 static void umtx_shm_free_reg(struct umtx_shm_reg *reg);
3622 
3623 static void
3624 umtx_shm_reg_delfree_tq(void *context __unused, int pending __unused)
3625 {
3626 	struct umtx_shm_reg_head d;
3627 	struct umtx_shm_reg *reg, *reg1;
3628 
3629 	TAILQ_INIT(&d);
3630 	mtx_lock(&umtx_shm_lock);
3631 	TAILQ_CONCAT(&d, &umtx_shm_reg_delfree, ushm_reg_link);
3632 	mtx_unlock(&umtx_shm_lock);
3633 	TAILQ_FOREACH_SAFE(reg, &d, ushm_reg_link, reg1) {
3634 		TAILQ_REMOVE(&d, reg, ushm_reg_link);
3635 		umtx_shm_free_reg(reg);
3636 	}
3637 }
3638 
3639 static struct task umtx_shm_reg_delfree_task =
3640     TASK_INITIALIZER(0, umtx_shm_reg_delfree_tq, NULL);
3641 
3642 static struct umtx_shm_reg *
3643 umtx_shm_find_reg_locked(const struct umtx_key *key)
3644 {
3645 	struct umtx_shm_reg *reg;
3646 	struct umtx_shm_reg_head *reg_head;
3647 
3648 	KASSERT(key->shared, ("umtx_p_find_rg: private key"));
3649 	mtx_assert(&umtx_shm_lock, MA_OWNED);
3650 	reg_head = &umtx_shm_registry[key->hash];
3651 	TAILQ_FOREACH(reg, reg_head, ushm_reg_link) {
3652 		KASSERT(reg->ushm_key.shared,
3653 		    ("non-shared key on reg %p %d", reg, reg->ushm_key.shared));
3654 		if (reg->ushm_key.info.shared.object ==
3655 		    key->info.shared.object &&
3656 		    reg->ushm_key.info.shared.offset ==
3657 		    key->info.shared.offset) {
3658 			KASSERT(reg->ushm_key.type == TYPE_SHM, ("TYPE_USHM"));
3659 			KASSERT(reg->ushm_refcnt > 0,
3660 			    ("reg %p refcnt 0 onlist", reg));
3661 			KASSERT((reg->ushm_flags & USHMF_REG_LINKED) != 0,
3662 			    ("reg %p not linked", reg));
3663 			reg->ushm_refcnt++;
3664 			return (reg);
3665 		}
3666 	}
3667 	return (NULL);
3668 }
3669 
3670 static struct umtx_shm_reg *
3671 umtx_shm_find_reg(const struct umtx_key *key)
3672 {
3673 	struct umtx_shm_reg *reg;
3674 
3675 	mtx_lock(&umtx_shm_lock);
3676 	reg = umtx_shm_find_reg_locked(key);
3677 	mtx_unlock(&umtx_shm_lock);
3678 	return (reg);
3679 }
3680 
3681 static void
3682 umtx_shm_free_reg(struct umtx_shm_reg *reg)
3683 {
3684 
3685 	chgumtxcnt(reg->ushm_cred->cr_ruidinfo, -1, 0);
3686 	crfree(reg->ushm_cred);
3687 	shm_drop(reg->ushm_obj);
3688 	uma_zfree(umtx_shm_reg_zone, reg);
3689 }
3690 
3691 static bool
3692 umtx_shm_unref_reg_locked(struct umtx_shm_reg *reg, bool force)
3693 {
3694 	bool res;
3695 
3696 	mtx_assert(&umtx_shm_lock, MA_OWNED);
3697 	KASSERT(reg->ushm_refcnt > 0, ("ushm_reg %p refcnt 0", reg));
3698 	reg->ushm_refcnt--;
3699 	res = reg->ushm_refcnt == 0;
3700 	if (res || force) {
3701 		if ((reg->ushm_flags & USHMF_REG_LINKED) != 0) {
3702 			TAILQ_REMOVE(&umtx_shm_registry[reg->ushm_key.hash],
3703 			    reg, ushm_reg_link);
3704 			reg->ushm_flags &= ~USHMF_REG_LINKED;
3705 		}
3706 		if ((reg->ushm_flags & USHMF_OBJ_LINKED) != 0) {
3707 			LIST_REMOVE(reg, ushm_obj_link);
3708 			reg->ushm_flags &= ~USHMF_OBJ_LINKED;
3709 		}
3710 	}
3711 	return (res);
3712 }
3713 
3714 static void
3715 umtx_shm_unref_reg(struct umtx_shm_reg *reg, bool force)
3716 {
3717 	vm_object_t object;
3718 	bool dofree;
3719 
3720 	if (force) {
3721 		object = reg->ushm_obj->shm_object;
3722 		VM_OBJECT_WLOCK(object);
3723 		object->flags |= OBJ_UMTXDEAD;
3724 		VM_OBJECT_WUNLOCK(object);
3725 	}
3726 	mtx_lock(&umtx_shm_lock);
3727 	dofree = umtx_shm_unref_reg_locked(reg, force);
3728 	mtx_unlock(&umtx_shm_lock);
3729 	if (dofree)
3730 		umtx_shm_free_reg(reg);
3731 }
3732 
3733 void
3734 umtx_shm_object_init(vm_object_t object)
3735 {
3736 
3737 	LIST_INIT(USHM_OBJ_UMTX(object));
3738 }
3739 
3740 void
3741 umtx_shm_object_terminated(vm_object_t object)
3742 {
3743 	struct umtx_shm_reg *reg, *reg1;
3744 	bool dofree;
3745 
3746 	dofree = false;
3747 	mtx_lock(&umtx_shm_lock);
3748 	LIST_FOREACH_SAFE(reg, USHM_OBJ_UMTX(object), ushm_obj_link, reg1) {
3749 		if (umtx_shm_unref_reg_locked(reg, true)) {
3750 			TAILQ_INSERT_TAIL(&umtx_shm_reg_delfree, reg,
3751 			    ushm_reg_link);
3752 			dofree = true;
3753 		}
3754 	}
3755 	mtx_unlock(&umtx_shm_lock);
3756 	if (dofree)
3757 		taskqueue_enqueue(taskqueue_thread, &umtx_shm_reg_delfree_task);
3758 }
3759 
3760 static int
3761 umtx_shm_create_reg(struct thread *td, const struct umtx_key *key,
3762     struct umtx_shm_reg **res)
3763 {
3764 	struct umtx_shm_reg *reg, *reg1;
3765 	struct ucred *cred;
3766 	int error;
3767 
3768 	reg = umtx_shm_find_reg(key);
3769 	if (reg != NULL) {
3770 		*res = reg;
3771 		return (0);
3772 	}
3773 	cred = td->td_ucred;
3774 	if (!chgumtxcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_UMTXP)))
3775 		return (ENOMEM);
3776 	reg = uma_zalloc(umtx_shm_reg_zone, M_WAITOK | M_ZERO);
3777 	reg->ushm_refcnt = 1;
3778 	bcopy(key, &reg->ushm_key, sizeof(*key));
3779 	reg->ushm_obj = shm_alloc(td->td_ucred, O_RDWR);
3780 	reg->ushm_cred = crhold(cred);
3781 	error = shm_dotruncate(reg->ushm_obj, PAGE_SIZE);
3782 	if (error != 0) {
3783 		umtx_shm_free_reg(reg);
3784 		return (error);
3785 	}
3786 	mtx_lock(&umtx_shm_lock);
3787 	reg1 = umtx_shm_find_reg_locked(key);
3788 	if (reg1 != NULL) {
3789 		mtx_unlock(&umtx_shm_lock);
3790 		umtx_shm_free_reg(reg);
3791 		*res = reg1;
3792 		return (0);
3793 	}
3794 	reg->ushm_refcnt++;
3795 	TAILQ_INSERT_TAIL(&umtx_shm_registry[key->hash], reg, ushm_reg_link);
3796 	LIST_INSERT_HEAD(USHM_OBJ_UMTX(key->info.shared.object), reg,
3797 	    ushm_obj_link);
3798 	reg->ushm_flags = USHMF_REG_LINKED | USHMF_OBJ_LINKED;
3799 	mtx_unlock(&umtx_shm_lock);
3800 	*res = reg;
3801 	return (0);
3802 }
3803 
3804 static int
3805 umtx_shm_alive(struct thread *td, void *addr)
3806 {
3807 	vm_map_t map;
3808 	vm_map_entry_t entry;
3809 	vm_object_t object;
3810 	vm_pindex_t pindex;
3811 	vm_prot_t prot;
3812 	int res, ret;
3813 	boolean_t wired;
3814 
3815 	map = &td->td_proc->p_vmspace->vm_map;
3816 	res = vm_map_lookup(&map, (uintptr_t)addr, VM_PROT_READ, &entry,
3817 	    &object, &pindex, &prot, &wired);
3818 	if (res != KERN_SUCCESS)
3819 		return (EFAULT);
3820 	if (object == NULL)
3821 		ret = EINVAL;
3822 	else
3823 		ret = (object->flags & OBJ_UMTXDEAD) != 0 ? ENOTTY : 0;
3824 	vm_map_lookup_done(map, entry);
3825 	return (ret);
3826 }
3827 
3828 static void
3829 umtx_shm_init(void)
3830 {
3831 	int i;
3832 
3833 	umtx_shm_reg_zone = uma_zcreate("umtx_shm", sizeof(struct umtx_shm_reg),
3834 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
3835 	mtx_init(&umtx_shm_lock, "umtxshm", NULL, MTX_DEF);
3836 	for (i = 0; i < nitems(umtx_shm_registry); i++)
3837 		TAILQ_INIT(&umtx_shm_registry[i]);
3838 }
3839 
3840 static int
3841 umtx_shm(struct thread *td, void *addr, u_int flags)
3842 {
3843 	struct umtx_key key;
3844 	struct umtx_shm_reg *reg;
3845 	struct file *fp;
3846 	int error, fd;
3847 
3848 	if (__bitcount(flags & (UMTX_SHM_CREAT | UMTX_SHM_LOOKUP |
3849 	    UMTX_SHM_DESTROY| UMTX_SHM_ALIVE)) != 1)
3850 		return (EINVAL);
3851 	if ((flags & UMTX_SHM_ALIVE) != 0)
3852 		return (umtx_shm_alive(td, addr));
3853 	error = umtx_key_get(addr, TYPE_SHM, PROCESS_SHARE, &key);
3854 	if (error != 0)
3855 		return (error);
3856 	KASSERT(key.shared == 1, ("non-shared key"));
3857 	if ((flags & UMTX_SHM_CREAT) != 0) {
3858 		error = umtx_shm_create_reg(td, &key, &reg);
3859 	} else {
3860 		reg = umtx_shm_find_reg(&key);
3861 		if (reg == NULL)
3862 			error = ESRCH;
3863 	}
3864 	umtx_key_release(&key);
3865 	if (error != 0)
3866 		return (error);
3867 	KASSERT(reg != NULL, ("no reg"));
3868 	if ((flags & UMTX_SHM_DESTROY) != 0) {
3869 		umtx_shm_unref_reg(reg, true);
3870 	} else {
3871 #if 0
3872 #ifdef MAC
3873 		error = mac_posixshm_check_open(td->td_ucred,
3874 		    reg->ushm_obj, FFLAGS(O_RDWR));
3875 		if (error == 0)
3876 #endif
3877 			error = shm_access(reg->ushm_obj, td->td_ucred,
3878 			    FFLAGS(O_RDWR));
3879 		if (error == 0)
3880 #endif
3881 			error = falloc_caps(td, &fp, &fd, O_CLOEXEC, NULL);
3882 		if (error == 0) {
3883 			shm_hold(reg->ushm_obj);
3884 			finit(fp, FFLAGS(O_RDWR), DTYPE_SHM, reg->ushm_obj,
3885 			    &shm_ops);
3886 			td->td_retval[0] = fd;
3887 			fdrop(fp, td);
3888 		}
3889 	}
3890 	umtx_shm_unref_reg(reg, false);
3891 	return (error);
3892 }
3893 
3894 static int
3895 __umtx_op_shm(struct thread *td, struct _umtx_op_args *uap)
3896 {
3897 
3898 	return (umtx_shm(td, uap->uaddr1, uap->val));
3899 }
3900 
3901 static int
3902 umtx_robust_lists(struct thread *td, struct umtx_robust_lists_params *rbp)
3903 {
3904 
3905 	td->td_rb_list = rbp->robust_list_offset;
3906 	td->td_rbp_list = rbp->robust_priv_list_offset;
3907 	td->td_rb_inact = rbp->robust_inact_offset;
3908 	return (0);
3909 }
3910 
3911 static int
3912 __umtx_op_robust_lists(struct thread *td, struct _umtx_op_args *uap)
3913 {
3914 	struct umtx_robust_lists_params rb;
3915 	int error;
3916 
3917 	if (uap->val > sizeof(rb))
3918 		return (EINVAL);
3919 	bzero(&rb, sizeof(rb));
3920 	error = copyin(uap->uaddr1, &rb, uap->val);
3921 	if (error != 0)
3922 		return (error);
3923 	return (umtx_robust_lists(td, &rb));
3924 }
3925 
3926 typedef int (*_umtx_op_func)(struct thread *td, struct _umtx_op_args *uap);
3927 
3928 static const _umtx_op_func op_table[] = {
3929 	[UMTX_OP_RESERVED0]	= __umtx_op_unimpl,
3930 	[UMTX_OP_RESERVED1]	= __umtx_op_unimpl,
3931 	[UMTX_OP_WAIT]		= __umtx_op_wait,
3932 	[UMTX_OP_WAKE]		= __umtx_op_wake,
3933 	[UMTX_OP_MUTEX_TRYLOCK]	= __umtx_op_trylock_umutex,
3934 	[UMTX_OP_MUTEX_LOCK]	= __umtx_op_lock_umutex,
3935 	[UMTX_OP_MUTEX_UNLOCK]	= __umtx_op_unlock_umutex,
3936 	[UMTX_OP_SET_CEILING]	= __umtx_op_set_ceiling,
3937 	[UMTX_OP_CV_WAIT]	= __umtx_op_cv_wait,
3938 	[UMTX_OP_CV_SIGNAL]	= __umtx_op_cv_signal,
3939 	[UMTX_OP_CV_BROADCAST]	= __umtx_op_cv_broadcast,
3940 	[UMTX_OP_WAIT_UINT]	= __umtx_op_wait_uint,
3941 	[UMTX_OP_RW_RDLOCK]	= __umtx_op_rw_rdlock,
3942 	[UMTX_OP_RW_WRLOCK]	= __umtx_op_rw_wrlock,
3943 	[UMTX_OP_RW_UNLOCK]	= __umtx_op_rw_unlock,
3944 	[UMTX_OP_WAIT_UINT_PRIVATE] = __umtx_op_wait_uint_private,
3945 	[UMTX_OP_WAKE_PRIVATE]	= __umtx_op_wake_private,
3946 	[UMTX_OP_MUTEX_WAIT]	= __umtx_op_wait_umutex,
3947 	[UMTX_OP_MUTEX_WAKE]	= __umtx_op_wake_umutex,
3948 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
3949 	[UMTX_OP_SEM_WAIT]	= __umtx_op_sem_wait,
3950 	[UMTX_OP_SEM_WAKE]	= __umtx_op_sem_wake,
3951 #else
3952 	[UMTX_OP_SEM_WAIT]	= __umtx_op_unimpl,
3953 	[UMTX_OP_SEM_WAKE]	= __umtx_op_unimpl,
3954 #endif
3955 	[UMTX_OP_NWAKE_PRIVATE]	= __umtx_op_nwake_private,
3956 	[UMTX_OP_MUTEX_WAKE2]	= __umtx_op_wake2_umutex,
3957 	[UMTX_OP_SEM2_WAIT]	= __umtx_op_sem2_wait,
3958 	[UMTX_OP_SEM2_WAKE]	= __umtx_op_sem2_wake,
3959 	[UMTX_OP_SHM]		= __umtx_op_shm,
3960 	[UMTX_OP_ROBUST_LISTS]	= __umtx_op_robust_lists,
3961 };
3962 
3963 int
3964 sys__umtx_op(struct thread *td, struct _umtx_op_args *uap)
3965 {
3966 
3967 	if ((unsigned)uap->op < nitems(op_table))
3968 		return (*op_table[uap->op])(td, uap);
3969 	return (EINVAL);
3970 }
3971 
3972 #ifdef COMPAT_FREEBSD32
3973 
3974 struct timespec32 {
3975 	int32_t tv_sec;
3976 	int32_t tv_nsec;
3977 };
3978 
3979 struct umtx_time32 {
3980 	struct	timespec32	timeout;
3981 	uint32_t		flags;
3982 	uint32_t		clockid;
3983 };
3984 
3985 static inline int
3986 umtx_copyin_timeout32(void *addr, struct timespec *tsp)
3987 {
3988 	struct timespec32 ts32;
3989 	int error;
3990 
3991 	error = copyin(addr, &ts32, sizeof(struct timespec32));
3992 	if (error == 0) {
3993 		if (ts32.tv_sec < 0 ||
3994 		    ts32.tv_nsec >= 1000000000 ||
3995 		    ts32.tv_nsec < 0)
3996 			error = EINVAL;
3997 		else {
3998 			tsp->tv_sec = ts32.tv_sec;
3999 			tsp->tv_nsec = ts32.tv_nsec;
4000 		}
4001 	}
4002 	return (error);
4003 }
4004 
4005 static inline int
4006 umtx_copyin_umtx_time32(const void *addr, size_t size, struct _umtx_time *tp)
4007 {
4008 	struct umtx_time32 t32;
4009 	int error;
4010 
4011 	t32.clockid = CLOCK_REALTIME;
4012 	t32.flags   = 0;
4013 	if (size <= sizeof(struct timespec32))
4014 		error = copyin(addr, &t32.timeout, sizeof(struct timespec32));
4015 	else
4016 		error = copyin(addr, &t32, sizeof(struct umtx_time32));
4017 	if (error != 0)
4018 		return (error);
4019 	if (t32.timeout.tv_sec < 0 ||
4020 	    t32.timeout.tv_nsec >= 1000000000 || t32.timeout.tv_nsec < 0)
4021 		return (EINVAL);
4022 	tp->_timeout.tv_sec = t32.timeout.tv_sec;
4023 	tp->_timeout.tv_nsec = t32.timeout.tv_nsec;
4024 	tp->_flags = t32.flags;
4025 	tp->_clockid = t32.clockid;
4026 	return (0);
4027 }
4028 
4029 static int
4030 __umtx_op_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
4031 {
4032 	struct _umtx_time *tm_p, timeout;
4033 	int error;
4034 
4035 	if (uap->uaddr2 == NULL)
4036 		tm_p = NULL;
4037 	else {
4038 		error = umtx_copyin_umtx_time32(uap->uaddr2,
4039 			(size_t)uap->uaddr1, &timeout);
4040 		if (error != 0)
4041 			return (error);
4042 		tm_p = &timeout;
4043 	}
4044 	return (do_wait(td, uap->obj, uap->val, tm_p, 1, 0));
4045 }
4046 
4047 static int
4048 __umtx_op_lock_umutex_compat32(struct thread *td, struct _umtx_op_args *uap)
4049 {
4050 	struct _umtx_time *tm_p, timeout;
4051 	int error;
4052 
4053 	/* Allow a null timespec (wait forever). */
4054 	if (uap->uaddr2 == NULL)
4055 		tm_p = NULL;
4056 	else {
4057 		error = umtx_copyin_umtx_time(uap->uaddr2,
4058 			    (size_t)uap->uaddr1, &timeout);
4059 		if (error != 0)
4060 			return (error);
4061 		tm_p = &timeout;
4062 	}
4063 	return (do_lock_umutex(td, uap->obj, tm_p, 0));
4064 }
4065 
4066 static int
4067 __umtx_op_wait_umutex_compat32(struct thread *td, struct _umtx_op_args *uap)
4068 {
4069 	struct _umtx_time *tm_p, timeout;
4070 	int error;
4071 
4072 	/* Allow a null timespec (wait forever). */
4073 	if (uap->uaddr2 == NULL)
4074 		tm_p = NULL;
4075 	else {
4076 		error = umtx_copyin_umtx_time32(uap->uaddr2,
4077 		    (size_t)uap->uaddr1, &timeout);
4078 		if (error != 0)
4079 			return (error);
4080 		tm_p = &timeout;
4081 	}
4082 	return (do_lock_umutex(td, uap->obj, tm_p, _UMUTEX_WAIT));
4083 }
4084 
4085 static int
4086 __umtx_op_cv_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
4087 {
4088 	struct timespec *ts, timeout;
4089 	int error;
4090 
4091 	/* Allow a null timespec (wait forever). */
4092 	if (uap->uaddr2 == NULL)
4093 		ts = NULL;
4094 	else {
4095 		error = umtx_copyin_timeout32(uap->uaddr2, &timeout);
4096 		if (error != 0)
4097 			return (error);
4098 		ts = &timeout;
4099 	}
4100 	return (do_cv_wait(td, uap->obj, uap->uaddr1, ts, uap->val));
4101 }
4102 
4103 static int
4104 __umtx_op_rw_rdlock_compat32(struct thread *td, struct _umtx_op_args *uap)
4105 {
4106 	struct _umtx_time timeout;
4107 	int error;
4108 
4109 	/* Allow a null timespec (wait forever). */
4110 	if (uap->uaddr2 == NULL) {
4111 		error = do_rw_rdlock(td, uap->obj, uap->val, 0);
4112 	} else {
4113 		error = umtx_copyin_umtx_time32(uap->uaddr2,
4114 		    (size_t)uap->uaddr1, &timeout);
4115 		if (error != 0)
4116 			return (error);
4117 		error = do_rw_rdlock(td, uap->obj, uap->val, &timeout);
4118 	}
4119 	return (error);
4120 }
4121 
4122 static int
4123 __umtx_op_rw_wrlock_compat32(struct thread *td, struct _umtx_op_args *uap)
4124 {
4125 	struct _umtx_time timeout;
4126 	int error;
4127 
4128 	/* Allow a null timespec (wait forever). */
4129 	if (uap->uaddr2 == NULL) {
4130 		error = do_rw_wrlock(td, uap->obj, 0);
4131 	} else {
4132 		error = umtx_copyin_umtx_time32(uap->uaddr2,
4133 		    (size_t)uap->uaddr1, &timeout);
4134 		if (error != 0)
4135 			return (error);
4136 		error = do_rw_wrlock(td, uap->obj, &timeout);
4137 	}
4138 	return (error);
4139 }
4140 
4141 static int
4142 __umtx_op_wait_uint_private_compat32(struct thread *td, struct _umtx_op_args *uap)
4143 {
4144 	struct _umtx_time *tm_p, timeout;
4145 	int error;
4146 
4147 	if (uap->uaddr2 == NULL)
4148 		tm_p = NULL;
4149 	else {
4150 		error = umtx_copyin_umtx_time32(
4151 		    uap->uaddr2, (size_t)uap->uaddr1,&timeout);
4152 		if (error != 0)
4153 			return (error);
4154 		tm_p = &timeout;
4155 	}
4156 	return (do_wait(td, uap->obj, uap->val, tm_p, 1, 1));
4157 }
4158 
4159 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
4160 static int
4161 __umtx_op_sem_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
4162 {
4163 	struct _umtx_time *tm_p, timeout;
4164 	int error;
4165 
4166 	/* Allow a null timespec (wait forever). */
4167 	if (uap->uaddr2 == NULL)
4168 		tm_p = NULL;
4169 	else {
4170 		error = umtx_copyin_umtx_time32(uap->uaddr2,
4171 		    (size_t)uap->uaddr1, &timeout);
4172 		if (error != 0)
4173 			return (error);
4174 		tm_p = &timeout;
4175 	}
4176 	return (do_sem_wait(td, uap->obj, tm_p));
4177 }
4178 #endif
4179 
4180 static int
4181 __umtx_op_sem2_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
4182 {
4183 	struct _umtx_time *tm_p, timeout;
4184 	int error;
4185 
4186 	/* Allow a null timespec (wait forever). */
4187 	if (uap->uaddr2 == NULL)
4188 		tm_p = NULL;
4189 	else {
4190 		error = umtx_copyin_umtx_time32(uap->uaddr2,
4191 		    (size_t)uap->uaddr1, &timeout);
4192 		if (error != 0)
4193 			return (error);
4194 		tm_p = &timeout;
4195 	}
4196 	return (do_sem2_wait(td, uap->obj, tm_p));
4197 }
4198 
4199 static int
4200 __umtx_op_nwake_private32(struct thread *td, struct _umtx_op_args *uap)
4201 {
4202 	uint32_t uaddrs[BATCH_SIZE], **upp;
4203 	int count, error, i, pos, tocopy;
4204 
4205 	upp = (uint32_t **)uap->obj;
4206 	error = 0;
4207 	for (count = uap->val, pos = 0; count > 0; count -= tocopy,
4208 	    pos += tocopy) {
4209 		tocopy = MIN(count, BATCH_SIZE);
4210 		error = copyin(upp + pos, uaddrs, tocopy * sizeof(uint32_t));
4211 		if (error != 0)
4212 			break;
4213 		for (i = 0; i < tocopy; ++i)
4214 			kern_umtx_wake(td, (void *)(intptr_t)uaddrs[i],
4215 			    INT_MAX, 1);
4216 		maybe_yield();
4217 	}
4218 	return (error);
4219 }
4220 
4221 struct umtx_robust_lists_params_compat32 {
4222 	uint32_t	robust_list_offset;
4223 	uint32_t	robust_priv_list_offset;
4224 	uint32_t	robust_inact_offset;
4225 };
4226 
4227 static int
4228 __umtx_op_robust_lists_compat32(struct thread *td, struct _umtx_op_args *uap)
4229 {
4230 	struct umtx_robust_lists_params rb;
4231 	struct umtx_robust_lists_params_compat32 rb32;
4232 	int error;
4233 
4234 	if (uap->val > sizeof(rb32))
4235 		return (EINVAL);
4236 	bzero(&rb, sizeof(rb));
4237 	bzero(&rb32, sizeof(rb32));
4238 	error = copyin(uap->uaddr1, &rb32, uap->val);
4239 	if (error != 0)
4240 		return (error);
4241 	rb.robust_list_offset = rb32.robust_list_offset;
4242 	rb.robust_priv_list_offset = rb32.robust_priv_list_offset;
4243 	rb.robust_inact_offset = rb32.robust_inact_offset;
4244 	return (umtx_robust_lists(td, &rb));
4245 }
4246 
4247 static const _umtx_op_func op_table_compat32[] = {
4248 	[UMTX_OP_RESERVED0]	= __umtx_op_unimpl,
4249 	[UMTX_OP_RESERVED1]	= __umtx_op_unimpl,
4250 	[UMTX_OP_WAIT]		= __umtx_op_wait_compat32,
4251 	[UMTX_OP_WAKE]		= __umtx_op_wake,
4252 	[UMTX_OP_MUTEX_TRYLOCK]	= __umtx_op_trylock_umutex,
4253 	[UMTX_OP_MUTEX_LOCK]	= __umtx_op_lock_umutex_compat32,
4254 	[UMTX_OP_MUTEX_UNLOCK]	= __umtx_op_unlock_umutex,
4255 	[UMTX_OP_SET_CEILING]	= __umtx_op_set_ceiling,
4256 	[UMTX_OP_CV_WAIT]	= __umtx_op_cv_wait_compat32,
4257 	[UMTX_OP_CV_SIGNAL]	= __umtx_op_cv_signal,
4258 	[UMTX_OP_CV_BROADCAST]	= __umtx_op_cv_broadcast,
4259 	[UMTX_OP_WAIT_UINT]	= __umtx_op_wait_compat32,
4260 	[UMTX_OP_RW_RDLOCK]	= __umtx_op_rw_rdlock_compat32,
4261 	[UMTX_OP_RW_WRLOCK]	= __umtx_op_rw_wrlock_compat32,
4262 	[UMTX_OP_RW_UNLOCK]	= __umtx_op_rw_unlock,
4263 	[UMTX_OP_WAIT_UINT_PRIVATE] = __umtx_op_wait_uint_private_compat32,
4264 	[UMTX_OP_WAKE_PRIVATE]	= __umtx_op_wake_private,
4265 	[UMTX_OP_MUTEX_WAIT]	= __umtx_op_wait_umutex_compat32,
4266 	[UMTX_OP_MUTEX_WAKE]	= __umtx_op_wake_umutex,
4267 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
4268 	[UMTX_OP_SEM_WAIT]	= __umtx_op_sem_wait_compat32,
4269 	[UMTX_OP_SEM_WAKE]	= __umtx_op_sem_wake,
4270 #else
4271 	[UMTX_OP_SEM_WAIT]	= __umtx_op_unimpl,
4272 	[UMTX_OP_SEM_WAKE]	= __umtx_op_unimpl,
4273 #endif
4274 	[UMTX_OP_NWAKE_PRIVATE]	= __umtx_op_nwake_private32,
4275 	[UMTX_OP_MUTEX_WAKE2]	= __umtx_op_wake2_umutex,
4276 	[UMTX_OP_SEM2_WAIT]	= __umtx_op_sem2_wait_compat32,
4277 	[UMTX_OP_SEM2_WAKE]	= __umtx_op_sem2_wake,
4278 	[UMTX_OP_SHM]		= __umtx_op_shm,
4279 	[UMTX_OP_ROBUST_LISTS]	= __umtx_op_robust_lists_compat32,
4280 };
4281 
4282 int
4283 freebsd32_umtx_op(struct thread *td, struct freebsd32_umtx_op_args *uap)
4284 {
4285 
4286 	if ((unsigned)uap->op < nitems(op_table_compat32)) {
4287 		return (*op_table_compat32[uap->op])(td,
4288 		    (struct _umtx_op_args *)uap);
4289 	}
4290 	return (EINVAL);
4291 }
4292 #endif
4293 
4294 void
4295 umtx_thread_init(struct thread *td)
4296 {
4297 
4298 	td->td_umtxq = umtxq_alloc();
4299 	td->td_umtxq->uq_thread = td;
4300 }
4301 
4302 void
4303 umtx_thread_fini(struct thread *td)
4304 {
4305 
4306 	umtxq_free(td->td_umtxq);
4307 }
4308 
4309 /*
4310  * It will be called when new thread is created, e.g fork().
4311  */
4312 void
4313 umtx_thread_alloc(struct thread *td)
4314 {
4315 	struct umtx_q *uq;
4316 
4317 	uq = td->td_umtxq;
4318 	uq->uq_inherited_pri = PRI_MAX;
4319 
4320 	KASSERT(uq->uq_flags == 0, ("uq_flags != 0"));
4321 	KASSERT(uq->uq_thread == td, ("uq_thread != td"));
4322 	KASSERT(uq->uq_pi_blocked == NULL, ("uq_pi_blocked != NULL"));
4323 	KASSERT(TAILQ_EMPTY(&uq->uq_pi_contested), ("uq_pi_contested is not empty"));
4324 }
4325 
4326 /*
4327  * exec() hook.
4328  *
4329  * Clear robust lists for all process' threads, not delaying the
4330  * cleanup to thread_exit hook, since the relevant address space is
4331  * destroyed right now.
4332  */
4333 static void
4334 umtx_exec_hook(void *arg __unused, struct proc *p,
4335     struct image_params *imgp __unused)
4336 {
4337 	struct thread *td;
4338 
4339 	KASSERT(p == curproc, ("need curproc"));
4340 	PROC_LOCK(p);
4341 	KASSERT((p->p_flag & P_HADTHREADS) == 0 ||
4342 	    (p->p_flag & P_STOPPED_SINGLE) != 0,
4343 	    ("curproc must be single-threaded"));
4344 	FOREACH_THREAD_IN_PROC(p, td) {
4345 		KASSERT(td == curthread ||
4346 		    ((td->td_flags & TDF_BOUNDARY) != 0 && TD_IS_SUSPENDED(td)),
4347 		    ("running thread %p %p", p, td));
4348 		PROC_UNLOCK(p);
4349 		umtx_thread_cleanup(td);
4350 		PROC_LOCK(p);
4351 		td->td_rb_list = td->td_rbp_list = td->td_rb_inact = 0;
4352 	}
4353 	PROC_UNLOCK(p);
4354 }
4355 
4356 /*
4357  * thread_exit() hook.
4358  */
4359 void
4360 umtx_thread_exit(struct thread *td)
4361 {
4362 
4363 	umtx_thread_cleanup(td);
4364 }
4365 
4366 static int
4367 umtx_read_uptr(struct thread *td, uintptr_t ptr, uintptr_t *res)
4368 {
4369 	u_long res1;
4370 #ifdef COMPAT_FREEBSD32
4371 	uint32_t res32;
4372 #endif
4373 	int error;
4374 
4375 #ifdef COMPAT_FREEBSD32
4376 	if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
4377 		error = fueword32((void *)ptr, &res32);
4378 		if (error == 0)
4379 			res1 = res32;
4380 	} else
4381 #endif
4382 	{
4383 		error = fueword((void *)ptr, &res1);
4384 	}
4385 	if (error == 0)
4386 		*res = res1;
4387 	else
4388 		error = EFAULT;
4389 	return (error);
4390 }
4391 
4392 static void
4393 umtx_read_rb_list(struct thread *td, struct umutex *m, uintptr_t *rb_list)
4394 {
4395 #ifdef COMPAT_FREEBSD32
4396 	struct umutex32 m32;
4397 
4398 	if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
4399 		memcpy(&m32, m, sizeof(m32));
4400 		*rb_list = m32.m_rb_lnk;
4401 	} else
4402 #endif
4403 		*rb_list = m->m_rb_lnk;
4404 }
4405 
4406 static int
4407 umtx_handle_rb(struct thread *td, uintptr_t rbp, uintptr_t *rb_list, bool inact)
4408 {
4409 	struct umutex m;
4410 	int error;
4411 
4412 	KASSERT(td->td_proc == curproc, ("need current vmspace"));
4413 	error = copyin((void *)rbp, &m, sizeof(m));
4414 	if (error != 0)
4415 		return (error);
4416 	if (rb_list != NULL)
4417 		umtx_read_rb_list(td, &m, rb_list);
4418 	if ((m.m_flags & UMUTEX_ROBUST) == 0)
4419 		return (EINVAL);
4420 	if ((m.m_owner & ~UMUTEX_CONTESTED) != td->td_tid)
4421 		/* inact is cleared after unlock, allow the inconsistency */
4422 		return (inact ? 0 : EINVAL);
4423 	return (do_unlock_umutex(td, (struct umutex *)rbp, true));
4424 }
4425 
4426 static void
4427 umtx_cleanup_rb_list(struct thread *td, uintptr_t rb_list, uintptr_t *rb_inact,
4428     const char *name)
4429 {
4430 	int error, i;
4431 	uintptr_t rbp;
4432 	bool inact;
4433 
4434 	if (rb_list == 0)
4435 		return;
4436 	error = umtx_read_uptr(td, rb_list, &rbp);
4437 	for (i = 0; error == 0 && rbp != 0 && i < umtx_max_rb; i++) {
4438 		if (rbp == *rb_inact) {
4439 			inact = true;
4440 			*rb_inact = 0;
4441 		} else
4442 			inact = false;
4443 		error = umtx_handle_rb(td, rbp, &rbp, inact);
4444 	}
4445 	if (i == umtx_max_rb && umtx_verbose_rb) {
4446 		uprintf("comm %s pid %d: reached umtx %smax rb %d\n",
4447 		    td->td_proc->p_comm, td->td_proc->p_pid, name, umtx_max_rb);
4448 	}
4449 	if (error != 0 && umtx_verbose_rb) {
4450 		uprintf("comm %s pid %d: handling %srb error %d\n",
4451 		    td->td_proc->p_comm, td->td_proc->p_pid, name, error);
4452 	}
4453 }
4454 
4455 /*
4456  * Clean up umtx data.
4457  */
4458 static void
4459 umtx_thread_cleanup(struct thread *td)
4460 {
4461 	struct umtx_q *uq;
4462 	struct umtx_pi *pi;
4463 	uintptr_t rb_inact;
4464 
4465 	/*
4466 	 * Disown pi mutexes.
4467 	 */
4468 	uq = td->td_umtxq;
4469 	if (uq != NULL) {
4470 		mtx_lock(&umtx_lock);
4471 		uq->uq_inherited_pri = PRI_MAX;
4472 		while ((pi = TAILQ_FIRST(&uq->uq_pi_contested)) != NULL) {
4473 			pi->pi_owner = NULL;
4474 			TAILQ_REMOVE(&uq->uq_pi_contested, pi, pi_link);
4475 		}
4476 		mtx_unlock(&umtx_lock);
4477 		thread_lock(td);
4478 		sched_lend_user_prio(td, PRI_MAX);
4479 		thread_unlock(td);
4480 	}
4481 
4482 	/*
4483 	 * Handle terminated robust mutexes.  Must be done after
4484 	 * robust pi disown, otherwise unlock could see unowned
4485 	 * entries.
4486 	 */
4487 	rb_inact = td->td_rb_inact;
4488 	if (rb_inact != 0)
4489 		(void)umtx_read_uptr(td, rb_inact, &rb_inact);
4490 	umtx_cleanup_rb_list(td, td->td_rb_list, &rb_inact, "");
4491 	umtx_cleanup_rb_list(td, td->td_rbp_list, &rb_inact, "priv ");
4492 	if (rb_inact != 0)
4493 		(void)umtx_handle_rb(td, rb_inact, NULL, true);
4494 }
4495