1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2015, 2016 The FreeBSD Foundation
5 * Copyright (c) 2004, David Xu <[email protected]>
6 * Copyright (c) 2002, Jeffrey Roberson <[email protected]>
7 * All rights reserved.
8 *
9 * Portions of this software were developed by Konstantin Belousov
10 * under sponsorship from the FreeBSD Foundation.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice unmodified, this list of conditions, and the following
17 * disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36
37 #include "opt_umtx_profiling.h"
38
39 #include <sys/param.h>
40 #include <sys/kernel.h>
41 #include <sys/fcntl.h>
42 #include <sys/file.h>
43 #include <sys/filedesc.h>
44 #include <sys/limits.h>
45 #include <sys/lock.h>
46 #include <sys/malloc.h>
47 #include <sys/mman.h>
48 #include <sys/mutex.h>
49 #include <sys/priv.h>
50 #include <sys/proc.h>
51 #include <sys/resource.h>
52 #include <sys/resourcevar.h>
53 #include <sys/rwlock.h>
54 #include <sys/sbuf.h>
55 #include <sys/sched.h>
56 #include <sys/smp.h>
57 #include <sys/sysctl.h>
58 #include <sys/sysent.h>
59 #include <sys/systm.h>
60 #include <sys/sysproto.h>
61 #include <sys/syscallsubr.h>
62 #include <sys/taskqueue.h>
63 #include <sys/time.h>
64 #include <sys/eventhandler.h>
65 #include <sys/umtx.h>
66
67 #include <security/mac/mac_framework.h>
68
69 #include <vm/vm.h>
70 #include <vm/vm_param.h>
71 #include <vm/pmap.h>
72 #include <vm/vm_map.h>
73 #include <vm/vm_object.h>
74
75 #include <machine/atomic.h>
76 #include <machine/cpu.h>
77
78 #ifdef COMPAT_FREEBSD32
79 #include <compat/freebsd32/freebsd32_proto.h>
80 #endif
81
82 #define _UMUTEX_TRY 1
83 #define _UMUTEX_WAIT 2
84
85 #ifdef UMTX_PROFILING
86 #define UPROF_PERC_BIGGER(w, f, sw, sf) \
87 (((w) > (sw)) || ((w) == (sw) && (f) > (sf)))
88 #endif
89
90 /* Priority inheritance mutex info. */
91 struct umtx_pi {
92 /* Owner thread */
93 struct thread *pi_owner;
94
95 /* Reference count */
96 int pi_refcount;
97
98 /* List entry to link umtx holding by thread */
99 TAILQ_ENTRY(umtx_pi) pi_link;
100
101 /* List entry in hash */
102 TAILQ_ENTRY(umtx_pi) pi_hashlink;
103
104 /* List for waiters */
105 TAILQ_HEAD(,umtx_q) pi_blocked;
106
107 /* Identify a userland lock object */
108 struct umtx_key pi_key;
109 };
110
111 /* A userland synchronous object user. */
112 struct umtx_q {
113 /* Linked list for the hash. */
114 TAILQ_ENTRY(umtx_q) uq_link;
115
116 /* Umtx key. */
117 struct umtx_key uq_key;
118
119 /* Umtx flags. */
120 int uq_flags;
121 #define UQF_UMTXQ 0x0001
122
123 /* The thread waits on. */
124 struct thread *uq_thread;
125
126 /*
127 * Blocked on PI mutex. read can use chain lock
128 * or umtx_lock, write must have both chain lock and
129 * umtx_lock being hold.
130 */
131 struct umtx_pi *uq_pi_blocked;
132
133 /* On blocked list */
134 TAILQ_ENTRY(umtx_q) uq_lockq;
135
136 /* Thread contending with us */
137 TAILQ_HEAD(,umtx_pi) uq_pi_contested;
138
139 /* Inherited priority from PP mutex */
140 u_char uq_inherited_pri;
141
142 /* Spare queue ready to be reused */
143 struct umtxq_queue *uq_spare_queue;
144
145 /* The queue we on */
146 struct umtxq_queue *uq_cur_queue;
147 };
148
149 TAILQ_HEAD(umtxq_head, umtx_q);
150
151 /* Per-key wait-queue */
152 struct umtxq_queue {
153 struct umtxq_head head;
154 struct umtx_key key;
155 LIST_ENTRY(umtxq_queue) link;
156 int length;
157 };
158
159 LIST_HEAD(umtxq_list, umtxq_queue);
160
161 /* Userland lock object's wait-queue chain */
162 struct umtxq_chain {
163 /* Lock for this chain. */
164 struct mtx uc_lock;
165
166 /* List of sleep queues. */
167 struct umtxq_list uc_queue[2];
168 #define UMTX_SHARED_QUEUE 0
169 #define UMTX_EXCLUSIVE_QUEUE 1
170
171 LIST_HEAD(, umtxq_queue) uc_spare_queue;
172
173 /* Busy flag */
174 char uc_busy;
175
176 /* Chain lock waiters */
177 int uc_waiters;
178
179 /* All PI in the list */
180 TAILQ_HEAD(,umtx_pi) uc_pi_list;
181
182 #ifdef UMTX_PROFILING
183 u_int length;
184 u_int max_length;
185 #endif
186 };
187
188 #define UMTXQ_LOCKED_ASSERT(uc) mtx_assert(&(uc)->uc_lock, MA_OWNED)
189
190 /*
191 * Don't propagate time-sharing priority, there is a security reason,
192 * a user can simply introduce PI-mutex, let thread A lock the mutex,
193 * and let another thread B block on the mutex, because B is
194 * sleeping, its priority will be boosted, this causes A's priority to
195 * be boosted via priority propagating too and will never be lowered even
196 * if it is using 100%CPU, this is unfair to other processes.
197 */
198
199 #define UPRI(td) (((td)->td_user_pri >= PRI_MIN_TIMESHARE &&\
200 (td)->td_user_pri <= PRI_MAX_TIMESHARE) ?\
201 PRI_MAX_TIMESHARE : (td)->td_user_pri)
202
203 #define GOLDEN_RATIO_PRIME 2654404609U
204 #ifndef UMTX_CHAINS
205 #define UMTX_CHAINS 512
206 #endif
207 #define UMTX_SHIFTS (__WORD_BIT - 9)
208
209 #define GET_SHARE(flags) \
210 (((flags) & USYNC_PROCESS_SHARED) == 0 ? THREAD_SHARE : PROCESS_SHARE)
211
212 #define BUSY_SPINS 200
213
214 struct abs_timeout {
215 int clockid;
216 bool is_abs_real; /* TIMER_ABSTIME && CLOCK_REALTIME* */
217 struct timespec cur;
218 struct timespec end;
219 };
220
221 #ifdef COMPAT_FREEBSD32
222 struct umutex32 {
223 volatile __lwpid_t m_owner; /* Owner of the mutex */
224 __uint32_t m_flags; /* Flags of the mutex */
225 __uint32_t m_ceilings[2]; /* Priority protect ceiling */
226 __uint32_t m_rb_lnk; /* Robust linkage */
227 __uint32_t m_pad;
228 __uint32_t m_spare[2];
229 };
230
231 _Static_assert(sizeof(struct umutex) == sizeof(struct umutex32), "umutex32");
232 _Static_assert(__offsetof(struct umutex, m_spare[0]) ==
233 __offsetof(struct umutex32, m_spare[0]), "m_spare32");
234 #endif
235
236 int umtx_shm_vnobj_persistent = 0;
237 SYSCTL_INT(_kern_ipc, OID_AUTO, umtx_vnode_persistent, CTLFLAG_RWTUN,
238 &umtx_shm_vnobj_persistent, 0,
239 "False forces destruction of umtx attached to file, on last close");
240 static int umtx_max_rb = 1000;
241 SYSCTL_INT(_kern_ipc, OID_AUTO, umtx_max_robust, CTLFLAG_RWTUN,
242 &umtx_max_rb, 0,
243 "");
244
245 static uma_zone_t umtx_pi_zone;
246 static struct umtxq_chain umtxq_chains[2][UMTX_CHAINS];
247 static MALLOC_DEFINE(M_UMTX, "umtx", "UMTX queue memory");
248 static int umtx_pi_allocated;
249
250 static SYSCTL_NODE(_debug, OID_AUTO, umtx, CTLFLAG_RW, 0, "umtx debug");
251 SYSCTL_INT(_debug_umtx, OID_AUTO, umtx_pi_allocated, CTLFLAG_RD,
252 &umtx_pi_allocated, 0, "Allocated umtx_pi");
253 static int umtx_verbose_rb = 1;
254 SYSCTL_INT(_debug_umtx, OID_AUTO, robust_faults_verbose, CTLFLAG_RWTUN,
255 &umtx_verbose_rb, 0,
256 "");
257
258 #ifdef UMTX_PROFILING
259 static long max_length;
260 SYSCTL_LONG(_debug_umtx, OID_AUTO, max_length, CTLFLAG_RD, &max_length, 0, "max_length");
261 static SYSCTL_NODE(_debug_umtx, OID_AUTO, chains, CTLFLAG_RD, 0, "umtx chain stats");
262 #endif
263
264 static void abs_timeout_update(struct abs_timeout *timo);
265
266 static void umtx_shm_init(void);
267 static void umtxq_sysinit(void *);
268 static void umtxq_hash(struct umtx_key *key);
269 static struct umtxq_chain *umtxq_getchain(struct umtx_key *key);
270 static void umtxq_lock(struct umtx_key *key);
271 static void umtxq_unlock(struct umtx_key *key);
272 static void umtxq_busy(struct umtx_key *key);
273 static void umtxq_unbusy(struct umtx_key *key);
274 static void umtxq_insert_queue(struct umtx_q *uq, int q);
275 static void umtxq_remove_queue(struct umtx_q *uq, int q);
276 static int umtxq_sleep(struct umtx_q *uq, const char *wmesg, struct abs_timeout *);
277 static int umtxq_count(struct umtx_key *key);
278 static struct umtx_pi *umtx_pi_alloc(int);
279 static void umtx_pi_free(struct umtx_pi *pi);
280 static int do_unlock_pp(struct thread *td, struct umutex *m, uint32_t flags,
281 bool rb);
282 static void umtx_thread_cleanup(struct thread *td);
283 static void umtx_exec_hook(void *arg __unused, struct proc *p __unused,
284 struct image_params *imgp __unused);
285 SYSINIT(umtx, SI_SUB_EVENTHANDLER+1, SI_ORDER_MIDDLE, umtxq_sysinit, NULL);
286
287 #define umtxq_signal(key, nwake) umtxq_signal_queue((key), (nwake), UMTX_SHARED_QUEUE)
288 #define umtxq_insert(uq) umtxq_insert_queue((uq), UMTX_SHARED_QUEUE)
289 #define umtxq_remove(uq) umtxq_remove_queue((uq), UMTX_SHARED_QUEUE)
290
291 static struct mtx umtx_lock;
292
293 #ifdef UMTX_PROFILING
294 static void
umtx_init_profiling(void)295 umtx_init_profiling(void)
296 {
297 struct sysctl_oid *chain_oid;
298 char chain_name[10];
299 int i;
300
301 for (i = 0; i < UMTX_CHAINS; ++i) {
302 snprintf(chain_name, sizeof(chain_name), "%d", i);
303 chain_oid = SYSCTL_ADD_NODE(NULL,
304 SYSCTL_STATIC_CHILDREN(_debug_umtx_chains), OID_AUTO,
305 chain_name, CTLFLAG_RD, NULL, "umtx hash stats");
306 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
307 "max_length0", CTLFLAG_RD, &umtxq_chains[0][i].max_length, 0, NULL);
308 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(chain_oid), OID_AUTO,
309 "max_length1", CTLFLAG_RD, &umtxq_chains[1][i].max_length, 0, NULL);
310 }
311 }
312
313 static int
sysctl_debug_umtx_chains_peaks(SYSCTL_HANDLER_ARGS)314 sysctl_debug_umtx_chains_peaks(SYSCTL_HANDLER_ARGS)
315 {
316 char buf[512];
317 struct sbuf sb;
318 struct umtxq_chain *uc;
319 u_int fract, i, j, tot, whole;
320 u_int sf0, sf1, sf2, sf3, sf4;
321 u_int si0, si1, si2, si3, si4;
322 u_int sw0, sw1, sw2, sw3, sw4;
323
324 sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN);
325 for (i = 0; i < 2; i++) {
326 tot = 0;
327 for (j = 0; j < UMTX_CHAINS; ++j) {
328 uc = &umtxq_chains[i][j];
329 mtx_lock(&uc->uc_lock);
330 tot += uc->max_length;
331 mtx_unlock(&uc->uc_lock);
332 }
333 if (tot == 0)
334 sbuf_printf(&sb, "%u) Empty ", i);
335 else {
336 sf0 = sf1 = sf2 = sf3 = sf4 = 0;
337 si0 = si1 = si2 = si3 = si4 = 0;
338 sw0 = sw1 = sw2 = sw3 = sw4 = 0;
339 for (j = 0; j < UMTX_CHAINS; j++) {
340 uc = &umtxq_chains[i][j];
341 mtx_lock(&uc->uc_lock);
342 whole = uc->max_length * 100;
343 mtx_unlock(&uc->uc_lock);
344 fract = (whole % tot) * 100;
345 if (UPROF_PERC_BIGGER(whole, fract, sw0, sf0)) {
346 sf0 = fract;
347 si0 = j;
348 sw0 = whole;
349 } else if (UPROF_PERC_BIGGER(whole, fract, sw1,
350 sf1)) {
351 sf1 = fract;
352 si1 = j;
353 sw1 = whole;
354 } else if (UPROF_PERC_BIGGER(whole, fract, sw2,
355 sf2)) {
356 sf2 = fract;
357 si2 = j;
358 sw2 = whole;
359 } else if (UPROF_PERC_BIGGER(whole, fract, sw3,
360 sf3)) {
361 sf3 = fract;
362 si3 = j;
363 sw3 = whole;
364 } else if (UPROF_PERC_BIGGER(whole, fract, sw4,
365 sf4)) {
366 sf4 = fract;
367 si4 = j;
368 sw4 = whole;
369 }
370 }
371 sbuf_printf(&sb, "queue %u:\n", i);
372 sbuf_printf(&sb, "1st: %u.%u%% idx: %u\n", sw0 / tot,
373 sf0 / tot, si0);
374 sbuf_printf(&sb, "2nd: %u.%u%% idx: %u\n", sw1 / tot,
375 sf1 / tot, si1);
376 sbuf_printf(&sb, "3rd: %u.%u%% idx: %u\n", sw2 / tot,
377 sf2 / tot, si2);
378 sbuf_printf(&sb, "4th: %u.%u%% idx: %u\n", sw3 / tot,
379 sf3 / tot, si3);
380 sbuf_printf(&sb, "5th: %u.%u%% idx: %u\n", sw4 / tot,
381 sf4 / tot, si4);
382 }
383 }
384 sbuf_trim(&sb);
385 sbuf_finish(&sb);
386 sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
387 sbuf_delete(&sb);
388 return (0);
389 }
390
391 static int
sysctl_debug_umtx_chains_clear(SYSCTL_HANDLER_ARGS)392 sysctl_debug_umtx_chains_clear(SYSCTL_HANDLER_ARGS)
393 {
394 struct umtxq_chain *uc;
395 u_int i, j;
396 int clear, error;
397
398 clear = 0;
399 error = sysctl_handle_int(oidp, &clear, 0, req);
400 if (error != 0 || req->newptr == NULL)
401 return (error);
402
403 if (clear != 0) {
404 for (i = 0; i < 2; ++i) {
405 for (j = 0; j < UMTX_CHAINS; ++j) {
406 uc = &umtxq_chains[i][j];
407 mtx_lock(&uc->uc_lock);
408 uc->length = 0;
409 uc->max_length = 0;
410 mtx_unlock(&uc->uc_lock);
411 }
412 }
413 }
414 return (0);
415 }
416
417 SYSCTL_PROC(_debug_umtx_chains, OID_AUTO, clear,
418 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
419 sysctl_debug_umtx_chains_clear, "I", "Clear umtx chains statistics");
420 SYSCTL_PROC(_debug_umtx_chains, OID_AUTO, peaks,
421 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
422 sysctl_debug_umtx_chains_peaks, "A", "Highest peaks in chains max length");
423 #endif
424
425 static void
umtxq_sysinit(void * arg __unused)426 umtxq_sysinit(void *arg __unused)
427 {
428 int i, j;
429
430 umtx_pi_zone = uma_zcreate("umtx pi", sizeof(struct umtx_pi),
431 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
432 for (i = 0; i < 2; ++i) {
433 for (j = 0; j < UMTX_CHAINS; ++j) {
434 mtx_init(&umtxq_chains[i][j].uc_lock, "umtxql", NULL,
435 MTX_DEF | MTX_DUPOK);
436 LIST_INIT(&umtxq_chains[i][j].uc_queue[0]);
437 LIST_INIT(&umtxq_chains[i][j].uc_queue[1]);
438 LIST_INIT(&umtxq_chains[i][j].uc_spare_queue);
439 TAILQ_INIT(&umtxq_chains[i][j].uc_pi_list);
440 umtxq_chains[i][j].uc_busy = 0;
441 umtxq_chains[i][j].uc_waiters = 0;
442 #ifdef UMTX_PROFILING
443 umtxq_chains[i][j].length = 0;
444 umtxq_chains[i][j].max_length = 0;
445 #endif
446 }
447 }
448 #ifdef UMTX_PROFILING
449 umtx_init_profiling();
450 #endif
451 mtx_init(&umtx_lock, "umtx lock", NULL, MTX_DEF);
452 EVENTHANDLER_REGISTER(process_exec, umtx_exec_hook, NULL,
453 EVENTHANDLER_PRI_ANY);
454 umtx_shm_init();
455 }
456
457 struct umtx_q *
umtxq_alloc(void)458 umtxq_alloc(void)
459 {
460 struct umtx_q *uq;
461
462 uq = malloc(sizeof(struct umtx_q), M_UMTX, M_WAITOK | M_ZERO);
463 uq->uq_spare_queue = malloc(sizeof(struct umtxq_queue), M_UMTX,
464 M_WAITOK | M_ZERO);
465 TAILQ_INIT(&uq->uq_spare_queue->head);
466 TAILQ_INIT(&uq->uq_pi_contested);
467 uq->uq_inherited_pri = PRI_MAX;
468 return (uq);
469 }
470
471 void
umtxq_free(struct umtx_q * uq)472 umtxq_free(struct umtx_q *uq)
473 {
474
475 MPASS(uq->uq_spare_queue != NULL);
476 free(uq->uq_spare_queue, M_UMTX);
477 free(uq, M_UMTX);
478 }
479
480 static inline void
umtxq_hash(struct umtx_key * key)481 umtxq_hash(struct umtx_key *key)
482 {
483 unsigned n;
484
485 n = (uintptr_t)key->info.both.a + key->info.both.b;
486 key->hash = ((n * GOLDEN_RATIO_PRIME) >> UMTX_SHIFTS) % UMTX_CHAINS;
487 }
488
489 static inline struct umtxq_chain *
umtxq_getchain(struct umtx_key * key)490 umtxq_getchain(struct umtx_key *key)
491 {
492
493 if (key->type <= TYPE_SEM)
494 return (&umtxq_chains[1][key->hash]);
495 return (&umtxq_chains[0][key->hash]);
496 }
497
498 /*
499 * Lock a chain.
500 */
501 static inline void
umtxq_lock(struct umtx_key * key)502 umtxq_lock(struct umtx_key *key)
503 {
504 struct umtxq_chain *uc;
505
506 uc = umtxq_getchain(key);
507 mtx_lock(&uc->uc_lock);
508 }
509
510 /*
511 * Unlock a chain.
512 */
513 static inline void
umtxq_unlock(struct umtx_key * key)514 umtxq_unlock(struct umtx_key *key)
515 {
516 struct umtxq_chain *uc;
517
518 uc = umtxq_getchain(key);
519 mtx_unlock(&uc->uc_lock);
520 }
521
522 /*
523 * Set chain to busy state when following operation
524 * may be blocked (kernel mutex can not be used).
525 */
526 static inline void
umtxq_busy(struct umtx_key * key)527 umtxq_busy(struct umtx_key *key)
528 {
529 struct umtxq_chain *uc;
530
531 uc = umtxq_getchain(key);
532 mtx_assert(&uc->uc_lock, MA_OWNED);
533 if (uc->uc_busy) {
534 #ifdef SMP
535 if (smp_cpus > 1) {
536 int count = BUSY_SPINS;
537 if (count > 0) {
538 umtxq_unlock(key);
539 while (uc->uc_busy && --count > 0)
540 cpu_spinwait();
541 umtxq_lock(key);
542 }
543 }
544 #endif
545 while (uc->uc_busy) {
546 uc->uc_waiters++;
547 msleep(uc, &uc->uc_lock, 0, "umtxqb", 0);
548 uc->uc_waiters--;
549 }
550 }
551 uc->uc_busy = 1;
552 }
553
554 /*
555 * Unbusy a chain.
556 */
557 static inline void
umtxq_unbusy(struct umtx_key * key)558 umtxq_unbusy(struct umtx_key *key)
559 {
560 struct umtxq_chain *uc;
561
562 uc = umtxq_getchain(key);
563 mtx_assert(&uc->uc_lock, MA_OWNED);
564 KASSERT(uc->uc_busy != 0, ("not busy"));
565 uc->uc_busy = 0;
566 if (uc->uc_waiters)
567 wakeup_one(uc);
568 }
569
570 static inline void
umtxq_unbusy_unlocked(struct umtx_key * key)571 umtxq_unbusy_unlocked(struct umtx_key *key)
572 {
573
574 umtxq_lock(key);
575 umtxq_unbusy(key);
576 umtxq_unlock(key);
577 }
578
579 static struct umtxq_queue *
umtxq_queue_lookup(struct umtx_key * key,int q)580 umtxq_queue_lookup(struct umtx_key *key, int q)
581 {
582 struct umtxq_queue *uh;
583 struct umtxq_chain *uc;
584
585 uc = umtxq_getchain(key);
586 UMTXQ_LOCKED_ASSERT(uc);
587 LIST_FOREACH(uh, &uc->uc_queue[q], link) {
588 if (umtx_key_match(&uh->key, key))
589 return (uh);
590 }
591
592 return (NULL);
593 }
594
595 static inline void
umtxq_insert_queue(struct umtx_q * uq,int q)596 umtxq_insert_queue(struct umtx_q *uq, int q)
597 {
598 struct umtxq_queue *uh;
599 struct umtxq_chain *uc;
600
601 uc = umtxq_getchain(&uq->uq_key);
602 UMTXQ_LOCKED_ASSERT(uc);
603 KASSERT((uq->uq_flags & UQF_UMTXQ) == 0, ("umtx_q is already on queue"));
604 uh = umtxq_queue_lookup(&uq->uq_key, q);
605 if (uh != NULL) {
606 LIST_INSERT_HEAD(&uc->uc_spare_queue, uq->uq_spare_queue, link);
607 } else {
608 uh = uq->uq_spare_queue;
609 uh->key = uq->uq_key;
610 LIST_INSERT_HEAD(&uc->uc_queue[q], uh, link);
611 #ifdef UMTX_PROFILING
612 uc->length++;
613 if (uc->length > uc->max_length) {
614 uc->max_length = uc->length;
615 if (uc->max_length > max_length)
616 max_length = uc->max_length;
617 }
618 #endif
619 }
620 uq->uq_spare_queue = NULL;
621
622 TAILQ_INSERT_TAIL(&uh->head, uq, uq_link);
623 uh->length++;
624 uq->uq_flags |= UQF_UMTXQ;
625 uq->uq_cur_queue = uh;
626 return;
627 }
628
629 static inline void
umtxq_remove_queue(struct umtx_q * uq,int q)630 umtxq_remove_queue(struct umtx_q *uq, int q)
631 {
632 struct umtxq_chain *uc;
633 struct umtxq_queue *uh;
634
635 uc = umtxq_getchain(&uq->uq_key);
636 UMTXQ_LOCKED_ASSERT(uc);
637 if (uq->uq_flags & UQF_UMTXQ) {
638 uh = uq->uq_cur_queue;
639 TAILQ_REMOVE(&uh->head, uq, uq_link);
640 uh->length--;
641 uq->uq_flags &= ~UQF_UMTXQ;
642 if (TAILQ_EMPTY(&uh->head)) {
643 KASSERT(uh->length == 0,
644 ("inconsistent umtxq_queue length"));
645 #ifdef UMTX_PROFILING
646 uc->length--;
647 #endif
648 LIST_REMOVE(uh, link);
649 } else {
650 uh = LIST_FIRST(&uc->uc_spare_queue);
651 KASSERT(uh != NULL, ("uc_spare_queue is empty"));
652 LIST_REMOVE(uh, link);
653 }
654 uq->uq_spare_queue = uh;
655 uq->uq_cur_queue = NULL;
656 }
657 }
658
659 /*
660 * Check if there are multiple waiters
661 */
662 static int
umtxq_count(struct umtx_key * key)663 umtxq_count(struct umtx_key *key)
664 {
665 struct umtxq_queue *uh;
666
667 UMTXQ_LOCKED_ASSERT(umtxq_getchain(key));
668 uh = umtxq_queue_lookup(key, UMTX_SHARED_QUEUE);
669 if (uh != NULL)
670 return (uh->length);
671 return (0);
672 }
673
674 /*
675 * Check if there are multiple PI waiters and returns first
676 * waiter.
677 */
678 static int
umtxq_count_pi(struct umtx_key * key,struct umtx_q ** first)679 umtxq_count_pi(struct umtx_key *key, struct umtx_q **first)
680 {
681 struct umtxq_queue *uh;
682
683 *first = NULL;
684 UMTXQ_LOCKED_ASSERT(umtxq_getchain(key));
685 uh = umtxq_queue_lookup(key, UMTX_SHARED_QUEUE);
686 if (uh != NULL) {
687 *first = TAILQ_FIRST(&uh->head);
688 return (uh->length);
689 }
690 return (0);
691 }
692
693 /*
694 * Check for possible stops and suspensions while executing a umtx
695 * locking operation.
696 *
697 * The sleep argument controls whether the function can handle a stop
698 * request itself or it should return ERESTART and the request is
699 * proceed at the kernel/user boundary in ast.
700 *
701 * Typically, when retrying due to casueword(9) failure (rv == 1), we
702 * should handle the stop requests there, with exception of cases when
703 * the thread busied the umtx key, or when functions return
704 * immediately if umtxq_check_susp() returned non-zero. On the other
705 * hand, retrying the whole lock operation, we better not stop there
706 * but delegate the handling to ast.
707 *
708 * If the request is for thread termination P_SINGLE_EXIT, we cannot
709 * handle it at all, and simply return EINTR.
710 */
711 static int
umtxq_check_susp(struct thread * td,bool sleep)712 umtxq_check_susp(struct thread *td, bool sleep)
713 {
714 struct proc *p;
715 int error;
716
717 /*
718 * The check for TDF_NEEDSUSPCHK is racy, but it is enough to
719 * eventually break the lockstep loop.
720 */
721 if ((td->td_flags & TDF_NEEDSUSPCHK) == 0)
722 return (0);
723 error = 0;
724 p = td->td_proc;
725 PROC_LOCK(p);
726 if (p->p_flag & P_SINGLE_EXIT)
727 error = EINTR;
728 else if (P_SHOULDSTOP(p) ||
729 ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_SUSPEND)))
730 error = sleep ? thread_suspend_check(0) : ERESTART;
731 PROC_UNLOCK(p);
732 return (error);
733 }
734
735 /*
736 * Wake up threads waiting on an userland object.
737 */
738
739 static int
umtxq_signal_queue(struct umtx_key * key,int n_wake,int q)740 umtxq_signal_queue(struct umtx_key *key, int n_wake, int q)
741 {
742 struct umtxq_queue *uh;
743 struct umtx_q *uq;
744 int ret;
745
746 ret = 0;
747 UMTXQ_LOCKED_ASSERT(umtxq_getchain(key));
748 uh = umtxq_queue_lookup(key, q);
749 if (uh != NULL) {
750 while ((uq = TAILQ_FIRST(&uh->head)) != NULL) {
751 umtxq_remove_queue(uq, q);
752 wakeup(uq);
753 if (++ret >= n_wake)
754 return (ret);
755 }
756 }
757 return (ret);
758 }
759
760
761 /*
762 * Wake up specified thread.
763 */
764 static inline void
umtxq_signal_thread(struct umtx_q * uq)765 umtxq_signal_thread(struct umtx_q *uq)
766 {
767
768 UMTXQ_LOCKED_ASSERT(umtxq_getchain(&uq->uq_key));
769 umtxq_remove(uq);
770 wakeup(uq);
771 }
772
773 static inline int
tstohz(const struct timespec * tsp)774 tstohz(const struct timespec *tsp)
775 {
776 struct timeval tv;
777
778 TIMESPEC_TO_TIMEVAL(&tv, tsp);
779 return tvtohz(&tv);
780 }
781
782 static void
abs_timeout_init(struct abs_timeout * timo,int clockid,int absolute,const struct timespec * timeout)783 abs_timeout_init(struct abs_timeout *timo, int clockid, int absolute,
784 const struct timespec *timeout)
785 {
786
787 timo->clockid = clockid;
788 if (!absolute) {
789 timo->is_abs_real = false;
790 abs_timeout_update(timo);
791 timespecadd(&timo->cur, timeout, &timo->end);
792 } else {
793 timo->end = *timeout;
794 timo->is_abs_real = clockid == CLOCK_REALTIME ||
795 clockid == CLOCK_REALTIME_FAST ||
796 clockid == CLOCK_REALTIME_PRECISE;
797 /*
798 * If is_abs_real, umtxq_sleep will read the clock
799 * after setting td_rtcgen; otherwise, read it here.
800 */
801 if (!timo->is_abs_real) {
802 abs_timeout_update(timo);
803 }
804 }
805 }
806
807 static void
abs_timeout_init2(struct abs_timeout * timo,const struct _umtx_time * umtxtime)808 abs_timeout_init2(struct abs_timeout *timo, const struct _umtx_time *umtxtime)
809 {
810
811 abs_timeout_init(timo, umtxtime->_clockid,
812 (umtxtime->_flags & UMTX_ABSTIME) != 0, &umtxtime->_timeout);
813 }
814
815 static inline void
abs_timeout_update(struct abs_timeout * timo)816 abs_timeout_update(struct abs_timeout *timo)
817 {
818
819 kern_clock_gettime(curthread, timo->clockid, &timo->cur);
820 }
821
822 static int
abs_timeout_gethz(struct abs_timeout * timo)823 abs_timeout_gethz(struct abs_timeout *timo)
824 {
825 struct timespec tts;
826
827 if (timespeccmp(&timo->end, &timo->cur, <=))
828 return (-1);
829 timespecsub(&timo->end, &timo->cur, &tts);
830 return (tstohz(&tts));
831 }
832
833 static uint32_t
umtx_unlock_val(uint32_t flags,bool rb)834 umtx_unlock_val(uint32_t flags, bool rb)
835 {
836
837 if (rb)
838 return (UMUTEX_RB_OWNERDEAD);
839 else if ((flags & UMUTEX_NONCONSISTENT) != 0)
840 return (UMUTEX_RB_NOTRECOV);
841 else
842 return (UMUTEX_UNOWNED);
843
844 }
845
846 /*
847 * Put thread into sleep state, before sleeping, check if
848 * thread was removed from umtx queue.
849 */
850 static inline int
umtxq_sleep(struct umtx_q * uq,const char * wmesg,struct abs_timeout * abstime)851 umtxq_sleep(struct umtx_q *uq, const char *wmesg, struct abs_timeout *abstime)
852 {
853 struct umtxq_chain *uc;
854 int error, timo;
855
856 if (abstime != NULL && abstime->is_abs_real) {
857 curthread->td_rtcgen = atomic_load_acq_int(&rtc_generation);
858 abs_timeout_update(abstime);
859 }
860
861 uc = umtxq_getchain(&uq->uq_key);
862 UMTXQ_LOCKED_ASSERT(uc);
863 for (;;) {
864 if (!(uq->uq_flags & UQF_UMTXQ)) {
865 error = 0;
866 break;
867 }
868 if (abstime != NULL) {
869 timo = abs_timeout_gethz(abstime);
870 if (timo < 0) {
871 error = ETIMEDOUT;
872 break;
873 }
874 } else
875 timo = 0;
876 error = msleep(uq, &uc->uc_lock, PCATCH | PDROP, wmesg, timo);
877 if (error == EINTR || error == ERESTART) {
878 umtxq_lock(&uq->uq_key);
879 break;
880 }
881 if (abstime != NULL) {
882 if (abstime->is_abs_real)
883 curthread->td_rtcgen =
884 atomic_load_acq_int(&rtc_generation);
885 abs_timeout_update(abstime);
886 }
887 umtxq_lock(&uq->uq_key);
888 }
889
890 curthread->td_rtcgen = 0;
891 return (error);
892 }
893
894 /*
895 * Convert userspace address into unique logical address.
896 */
897 int
umtx_key_get(const void * addr,int type,int share,struct umtx_key * key)898 umtx_key_get(const void *addr, int type, int share, struct umtx_key *key)
899 {
900 struct thread *td = curthread;
901 vm_map_t map;
902 vm_map_entry_t entry;
903 vm_pindex_t pindex;
904 vm_prot_t prot;
905 boolean_t wired;
906
907 key->type = type;
908 if (share == THREAD_SHARE) {
909 key->shared = 0;
910 key->info.private.vs = td->td_proc->p_vmspace;
911 key->info.private.addr = (uintptr_t)addr;
912 } else {
913 MPASS(share == PROCESS_SHARE || share == AUTO_SHARE);
914 map = &td->td_proc->p_vmspace->vm_map;
915 if (vm_map_lookup(&map, (vm_offset_t)addr, VM_PROT_WRITE,
916 &entry, &key->info.shared.object, &pindex, &prot,
917 &wired) != KERN_SUCCESS) {
918 return (EFAULT);
919 }
920
921 if ((share == PROCESS_SHARE) ||
922 (share == AUTO_SHARE &&
923 VM_INHERIT_SHARE == entry->inheritance)) {
924 key->shared = 1;
925 key->info.shared.offset = (vm_offset_t)addr -
926 entry->start + entry->offset;
927 vm_object_reference(key->info.shared.object);
928 } else {
929 key->shared = 0;
930 key->info.private.vs = td->td_proc->p_vmspace;
931 key->info.private.addr = (uintptr_t)addr;
932 }
933 vm_map_lookup_done(map, entry);
934 }
935
936 umtxq_hash(key);
937 return (0);
938 }
939
940 /*
941 * Release key.
942 */
943 void
umtx_key_release(struct umtx_key * key)944 umtx_key_release(struct umtx_key *key)
945 {
946 if (key->shared)
947 vm_object_deallocate(key->info.shared.object);
948 }
949
950 /*
951 * Fetch and compare value, sleep on the address if value is not changed.
952 */
953 static int
do_wait(struct thread * td,void * addr,u_long id,struct _umtx_time * timeout,int compat32,int is_private)954 do_wait(struct thread *td, void *addr, u_long id,
955 struct _umtx_time *timeout, int compat32, int is_private)
956 {
957 struct abs_timeout timo;
958 struct umtx_q *uq;
959 u_long tmp;
960 uint32_t tmp32;
961 int error = 0;
962
963 uq = td->td_umtxq;
964 if ((error = umtx_key_get(addr, TYPE_SIMPLE_WAIT,
965 is_private ? THREAD_SHARE : AUTO_SHARE, &uq->uq_key)) != 0)
966 return (error);
967
968 if (timeout != NULL)
969 abs_timeout_init2(&timo, timeout);
970
971 umtxq_lock(&uq->uq_key);
972 umtxq_insert(uq);
973 umtxq_unlock(&uq->uq_key);
974 if (compat32 == 0) {
975 error = fueword(addr, &tmp);
976 if (error != 0)
977 error = EFAULT;
978 } else {
979 error = fueword32(addr, &tmp32);
980 if (error == 0)
981 tmp = tmp32;
982 else
983 error = EFAULT;
984 }
985 umtxq_lock(&uq->uq_key);
986 if (error == 0) {
987 if (tmp == id)
988 error = umtxq_sleep(uq, "uwait", timeout == NULL ?
989 NULL : &timo);
990 if ((uq->uq_flags & UQF_UMTXQ) == 0)
991 error = 0;
992 else
993 umtxq_remove(uq);
994 } else if ((uq->uq_flags & UQF_UMTXQ) != 0) {
995 umtxq_remove(uq);
996 }
997 umtxq_unlock(&uq->uq_key);
998 umtx_key_release(&uq->uq_key);
999 if (error == ERESTART)
1000 error = EINTR;
1001 return (error);
1002 }
1003
1004 /*
1005 * Wake up threads sleeping on the specified address.
1006 */
1007 int
kern_umtx_wake(struct thread * td,void * uaddr,int n_wake,int is_private)1008 kern_umtx_wake(struct thread *td, void *uaddr, int n_wake, int is_private)
1009 {
1010 struct umtx_key key;
1011 int ret;
1012
1013 if ((ret = umtx_key_get(uaddr, TYPE_SIMPLE_WAIT,
1014 is_private ? THREAD_SHARE : AUTO_SHARE, &key)) != 0)
1015 return (ret);
1016 umtxq_lock(&key);
1017 umtxq_signal(&key, n_wake);
1018 umtxq_unlock(&key);
1019 umtx_key_release(&key);
1020 return (0);
1021 }
1022
1023 /*
1024 * Lock PTHREAD_PRIO_NONE protocol POSIX mutex.
1025 */
1026 static int
do_lock_normal(struct thread * td,struct umutex * m,uint32_t flags,struct _umtx_time * timeout,int mode)1027 do_lock_normal(struct thread *td, struct umutex *m, uint32_t flags,
1028 struct _umtx_time *timeout, int mode)
1029 {
1030 struct abs_timeout timo;
1031 struct umtx_q *uq;
1032 uint32_t owner, old, id;
1033 int error, rv;
1034
1035 id = td->td_tid;
1036 uq = td->td_umtxq;
1037 error = 0;
1038 if (timeout != NULL)
1039 abs_timeout_init2(&timo, timeout);
1040
1041 /*
1042 * Care must be exercised when dealing with umtx structure. It
1043 * can fault on any access.
1044 */
1045 for (;;) {
1046 rv = fueword32(&m->m_owner, &owner);
1047 if (rv == -1)
1048 return (EFAULT);
1049 if (mode == _UMUTEX_WAIT) {
1050 if (owner == UMUTEX_UNOWNED ||
1051 owner == UMUTEX_CONTESTED ||
1052 owner == UMUTEX_RB_OWNERDEAD ||
1053 owner == UMUTEX_RB_NOTRECOV)
1054 return (0);
1055 } else {
1056 /*
1057 * Robust mutex terminated. Kernel duty is to
1058 * return EOWNERDEAD to the userspace. The
1059 * umutex.m_flags UMUTEX_NONCONSISTENT is set
1060 * by the common userspace code.
1061 */
1062 if (owner == UMUTEX_RB_OWNERDEAD) {
1063 rv = casueword32(&m->m_owner,
1064 UMUTEX_RB_OWNERDEAD, &owner,
1065 id | UMUTEX_CONTESTED);
1066 if (rv == -1)
1067 return (EFAULT);
1068 if (rv == 0) {
1069 MPASS(owner == UMUTEX_RB_OWNERDEAD);
1070 return (EOWNERDEAD); /* success */
1071 }
1072 MPASS(rv == 1);
1073 rv = umtxq_check_susp(td, false);
1074 if (rv != 0)
1075 return (rv);
1076 continue;
1077 }
1078 if (owner == UMUTEX_RB_NOTRECOV)
1079 return (ENOTRECOVERABLE);
1080
1081 /*
1082 * Try the uncontested case. This should be
1083 * done in userland.
1084 */
1085 rv = casueword32(&m->m_owner, UMUTEX_UNOWNED,
1086 &owner, id);
1087 /* The address was invalid. */
1088 if (rv == -1)
1089 return (EFAULT);
1090
1091 /* The acquire succeeded. */
1092 if (rv == 0) {
1093 MPASS(owner == UMUTEX_UNOWNED);
1094 return (0);
1095 }
1096
1097 /*
1098 * If no one owns it but it is contested try
1099 * to acquire it.
1100 */
1101 MPASS(rv == 1);
1102 if (owner == UMUTEX_CONTESTED) {
1103 rv = casueword32(&m->m_owner,
1104 UMUTEX_CONTESTED, &owner,
1105 id | UMUTEX_CONTESTED);
1106 /* The address was invalid. */
1107 if (rv == -1)
1108 return (EFAULT);
1109 if (rv == 0) {
1110 MPASS(owner == UMUTEX_CONTESTED);
1111 return (0);
1112 }
1113 if (rv == 1) {
1114 rv = umtxq_check_susp(td, false);
1115 if (rv != 0)
1116 return (rv);
1117 }
1118
1119 /*
1120 * If this failed the lock has
1121 * changed, restart.
1122 */
1123 continue;
1124 }
1125
1126 /* rv == 1 but not contested, likely store failure */
1127 rv = umtxq_check_susp(td, false);
1128 if (rv != 0)
1129 return (rv);
1130 }
1131
1132 if (mode == _UMUTEX_TRY)
1133 return (EBUSY);
1134
1135 /*
1136 * If we caught a signal, we have retried and now
1137 * exit immediately.
1138 */
1139 if (error != 0)
1140 return (error);
1141
1142 if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX,
1143 GET_SHARE(flags), &uq->uq_key)) != 0)
1144 return (error);
1145
1146 umtxq_lock(&uq->uq_key);
1147 umtxq_busy(&uq->uq_key);
1148 umtxq_insert(uq);
1149 umtxq_unlock(&uq->uq_key);
1150
1151 /*
1152 * Set the contested bit so that a release in user space
1153 * knows to use the system call for unlock. If this fails
1154 * either some one else has acquired the lock or it has been
1155 * released.
1156 */
1157 rv = casueword32(&m->m_owner, owner, &old,
1158 owner | UMUTEX_CONTESTED);
1159
1160 /* The address was invalid or casueword failed to store. */
1161 if (rv == -1 || rv == 1) {
1162 umtxq_lock(&uq->uq_key);
1163 umtxq_remove(uq);
1164 umtxq_unbusy(&uq->uq_key);
1165 umtxq_unlock(&uq->uq_key);
1166 umtx_key_release(&uq->uq_key);
1167 if (rv == -1)
1168 return (EFAULT);
1169 if (rv == 1) {
1170 rv = umtxq_check_susp(td, false);
1171 if (rv != 0)
1172 return (rv);
1173 }
1174 continue;
1175 }
1176
1177 /*
1178 * We set the contested bit, sleep. Otherwise the lock changed
1179 * and we need to retry or we lost a race to the thread
1180 * unlocking the umtx.
1181 */
1182 umtxq_lock(&uq->uq_key);
1183 umtxq_unbusy(&uq->uq_key);
1184 MPASS(old == owner);
1185 error = umtxq_sleep(uq, "umtxn", timeout == NULL ?
1186 NULL : &timo);
1187 umtxq_remove(uq);
1188 umtxq_unlock(&uq->uq_key);
1189 umtx_key_release(&uq->uq_key);
1190
1191 if (error == 0)
1192 error = umtxq_check_susp(td, false);
1193 }
1194
1195 return (0);
1196 }
1197
1198 /*
1199 * Unlock PTHREAD_PRIO_NONE protocol POSIX mutex.
1200 */
1201 static int
do_unlock_normal(struct thread * td,struct umutex * m,uint32_t flags,bool rb)1202 do_unlock_normal(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
1203 {
1204 struct umtx_key key;
1205 uint32_t owner, old, id, newlock;
1206 int error, count;
1207
1208 id = td->td_tid;
1209
1210 again:
1211 /*
1212 * Make sure we own this mtx.
1213 */
1214 error = fueword32(&m->m_owner, &owner);
1215 if (error == -1)
1216 return (EFAULT);
1217
1218 if ((owner & ~UMUTEX_CONTESTED) != id)
1219 return (EPERM);
1220
1221 newlock = umtx_unlock_val(flags, rb);
1222 if ((owner & UMUTEX_CONTESTED) == 0) {
1223 error = casueword32(&m->m_owner, owner, &old, newlock);
1224 if (error == -1)
1225 return (EFAULT);
1226 if (error == 1) {
1227 error = umtxq_check_susp(td, false);
1228 if (error != 0)
1229 return (error);
1230 goto again;
1231 }
1232 MPASS(old == owner);
1233 return (0);
1234 }
1235
1236 /* We should only ever be in here for contested locks */
1237 if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX, GET_SHARE(flags),
1238 &key)) != 0)
1239 return (error);
1240
1241 umtxq_lock(&key);
1242 umtxq_busy(&key);
1243 count = umtxq_count(&key);
1244 umtxq_unlock(&key);
1245
1246 /*
1247 * When unlocking the umtx, it must be marked as unowned if
1248 * there is zero or one thread only waiting for it.
1249 * Otherwise, it must be marked as contested.
1250 */
1251 if (count > 1)
1252 newlock |= UMUTEX_CONTESTED;
1253 error = casueword32(&m->m_owner, owner, &old, newlock);
1254 umtxq_lock(&key);
1255 umtxq_signal(&key, 1);
1256 umtxq_unbusy(&key);
1257 umtxq_unlock(&key);
1258 umtx_key_release(&key);
1259 if (error == -1)
1260 return (EFAULT);
1261 if (error == 1) {
1262 if (old != owner)
1263 return (EINVAL);
1264 error = umtxq_check_susp(td, false);
1265 if (error != 0)
1266 return (error);
1267 goto again;
1268 }
1269 return (0);
1270 }
1271
1272 /*
1273 * Check if the mutex is available and wake up a waiter,
1274 * only for simple mutex.
1275 */
1276 static int
do_wake_umutex(struct thread * td,struct umutex * m)1277 do_wake_umutex(struct thread *td, struct umutex *m)
1278 {
1279 struct umtx_key key;
1280 uint32_t owner;
1281 uint32_t flags;
1282 int error;
1283 int count;
1284
1285 again:
1286 error = fueword32(&m->m_owner, &owner);
1287 if (error == -1)
1288 return (EFAULT);
1289
1290 if ((owner & ~UMUTEX_CONTESTED) != 0 && owner != UMUTEX_RB_OWNERDEAD &&
1291 owner != UMUTEX_RB_NOTRECOV)
1292 return (0);
1293
1294 error = fueword32(&m->m_flags, &flags);
1295 if (error == -1)
1296 return (EFAULT);
1297
1298 /* We should only ever be in here for contested locks */
1299 if ((error = umtx_key_get(m, TYPE_NORMAL_UMUTEX, GET_SHARE(flags),
1300 &key)) != 0)
1301 return (error);
1302
1303 umtxq_lock(&key);
1304 umtxq_busy(&key);
1305 count = umtxq_count(&key);
1306 umtxq_unlock(&key);
1307
1308 if (count <= 1 && owner != UMUTEX_RB_OWNERDEAD &&
1309 owner != UMUTEX_RB_NOTRECOV) {
1310 error = casueword32(&m->m_owner, UMUTEX_CONTESTED, &owner,
1311 UMUTEX_UNOWNED);
1312 if (error == -1) {
1313 error = EFAULT;
1314 } else if (error == 1) {
1315 umtxq_lock(&key);
1316 umtxq_unbusy(&key);
1317 umtxq_unlock(&key);
1318 umtx_key_release(&key);
1319 error = umtxq_check_susp(td, false);
1320 if (error != 0)
1321 return (error);
1322 goto again;
1323 }
1324 }
1325
1326 umtxq_lock(&key);
1327 if (error == 0 && count != 0) {
1328 MPASS((owner & ~UMUTEX_CONTESTED) == 0 ||
1329 owner == UMUTEX_RB_OWNERDEAD ||
1330 owner == UMUTEX_RB_NOTRECOV);
1331 umtxq_signal(&key, 1);
1332 }
1333 umtxq_unbusy(&key);
1334 umtxq_unlock(&key);
1335 umtx_key_release(&key);
1336 return (error);
1337 }
1338
1339 /*
1340 * Check if the mutex has waiters and tries to fix contention bit.
1341 */
1342 static int
do_wake2_umutex(struct thread * td,struct umutex * m,uint32_t flags)1343 do_wake2_umutex(struct thread *td, struct umutex *m, uint32_t flags)
1344 {
1345 struct umtx_key key;
1346 uint32_t owner, old;
1347 int type;
1348 int error;
1349 int count;
1350
1351 switch (flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT |
1352 UMUTEX_ROBUST)) {
1353 case 0:
1354 case UMUTEX_ROBUST:
1355 type = TYPE_NORMAL_UMUTEX;
1356 break;
1357 case UMUTEX_PRIO_INHERIT:
1358 type = TYPE_PI_UMUTEX;
1359 break;
1360 case (UMUTEX_PRIO_INHERIT | UMUTEX_ROBUST):
1361 type = TYPE_PI_ROBUST_UMUTEX;
1362 break;
1363 case UMUTEX_PRIO_PROTECT:
1364 type = TYPE_PP_UMUTEX;
1365 break;
1366 case (UMUTEX_PRIO_PROTECT | UMUTEX_ROBUST):
1367 type = TYPE_PP_ROBUST_UMUTEX;
1368 break;
1369 default:
1370 return (EINVAL);
1371 }
1372 if ((error = umtx_key_get(m, type, GET_SHARE(flags), &key)) != 0)
1373 return (error);
1374
1375 owner = 0;
1376 umtxq_lock(&key);
1377 umtxq_busy(&key);
1378 count = umtxq_count(&key);
1379 umtxq_unlock(&key);
1380
1381 error = fueword32(&m->m_owner, &owner);
1382 if (error == -1)
1383 error = EFAULT;
1384
1385 /*
1386 * Only repair contention bit if there is a waiter, this means
1387 * the mutex is still being referenced by userland code,
1388 * otherwise don't update any memory.
1389 */
1390 while (error == 0 && (owner & UMUTEX_CONTESTED) == 0 &&
1391 (count > 1 || (count == 1 && (owner & ~UMUTEX_CONTESTED) != 0))) {
1392 error = casueword32(&m->m_owner, owner, &old,
1393 owner | UMUTEX_CONTESTED);
1394 if (error == -1) {
1395 error = EFAULT;
1396 break;
1397 }
1398 if (error == 0) {
1399 MPASS(old == owner);
1400 break;
1401 }
1402 owner = old;
1403 error = umtxq_check_susp(td, false);
1404 }
1405
1406 umtxq_lock(&key);
1407 if (error == EFAULT) {
1408 umtxq_signal(&key, INT_MAX);
1409 } else if (count != 0 && ((owner & ~UMUTEX_CONTESTED) == 0 ||
1410 owner == UMUTEX_RB_OWNERDEAD || owner == UMUTEX_RB_NOTRECOV))
1411 umtxq_signal(&key, 1);
1412 umtxq_unbusy(&key);
1413 umtxq_unlock(&key);
1414 umtx_key_release(&key);
1415 return (error);
1416 }
1417
1418 static inline struct umtx_pi *
umtx_pi_alloc(int flags)1419 umtx_pi_alloc(int flags)
1420 {
1421 struct umtx_pi *pi;
1422
1423 pi = uma_zalloc(umtx_pi_zone, M_ZERO | flags);
1424 TAILQ_INIT(&pi->pi_blocked);
1425 atomic_add_int(&umtx_pi_allocated, 1);
1426 return (pi);
1427 }
1428
1429 static inline void
umtx_pi_free(struct umtx_pi * pi)1430 umtx_pi_free(struct umtx_pi *pi)
1431 {
1432 uma_zfree(umtx_pi_zone, pi);
1433 atomic_add_int(&umtx_pi_allocated, -1);
1434 }
1435
1436 /*
1437 * Adjust the thread's position on a pi_state after its priority has been
1438 * changed.
1439 */
1440 static int
umtx_pi_adjust_thread(struct umtx_pi * pi,struct thread * td)1441 umtx_pi_adjust_thread(struct umtx_pi *pi, struct thread *td)
1442 {
1443 struct umtx_q *uq, *uq1, *uq2;
1444 struct thread *td1;
1445
1446 mtx_assert(&umtx_lock, MA_OWNED);
1447 if (pi == NULL)
1448 return (0);
1449
1450 uq = td->td_umtxq;
1451
1452 /*
1453 * Check if the thread needs to be moved on the blocked chain.
1454 * It needs to be moved if either its priority is lower than
1455 * the previous thread or higher than the next thread.
1456 */
1457 uq1 = TAILQ_PREV(uq, umtxq_head, uq_lockq);
1458 uq2 = TAILQ_NEXT(uq, uq_lockq);
1459 if ((uq1 != NULL && UPRI(td) < UPRI(uq1->uq_thread)) ||
1460 (uq2 != NULL && UPRI(td) > UPRI(uq2->uq_thread))) {
1461 /*
1462 * Remove thread from blocked chain and determine where
1463 * it should be moved to.
1464 */
1465 TAILQ_REMOVE(&pi->pi_blocked, uq, uq_lockq);
1466 TAILQ_FOREACH(uq1, &pi->pi_blocked, uq_lockq) {
1467 td1 = uq1->uq_thread;
1468 MPASS(td1->td_proc->p_magic == P_MAGIC);
1469 if (UPRI(td1) > UPRI(td))
1470 break;
1471 }
1472
1473 if (uq1 == NULL)
1474 TAILQ_INSERT_TAIL(&pi->pi_blocked, uq, uq_lockq);
1475 else
1476 TAILQ_INSERT_BEFORE(uq1, uq, uq_lockq);
1477 }
1478 return (1);
1479 }
1480
1481 static struct umtx_pi *
umtx_pi_next(struct umtx_pi * pi)1482 umtx_pi_next(struct umtx_pi *pi)
1483 {
1484 struct umtx_q *uq_owner;
1485
1486 if (pi->pi_owner == NULL)
1487 return (NULL);
1488 uq_owner = pi->pi_owner->td_umtxq;
1489 if (uq_owner == NULL)
1490 return (NULL);
1491 return (uq_owner->uq_pi_blocked);
1492 }
1493
1494 /*
1495 * Floyd's Cycle-Finding Algorithm.
1496 */
1497 static bool
umtx_pi_check_loop(struct umtx_pi * pi)1498 umtx_pi_check_loop(struct umtx_pi *pi)
1499 {
1500 struct umtx_pi *pi1; /* fast iterator */
1501
1502 mtx_assert(&umtx_lock, MA_OWNED);
1503 if (pi == NULL)
1504 return (false);
1505 pi1 = pi;
1506 for (;;) {
1507 pi = umtx_pi_next(pi);
1508 if (pi == NULL)
1509 break;
1510 pi1 = umtx_pi_next(pi1);
1511 if (pi1 == NULL)
1512 break;
1513 pi1 = umtx_pi_next(pi1);
1514 if (pi1 == NULL)
1515 break;
1516 if (pi == pi1)
1517 return (true);
1518 }
1519 return (false);
1520 }
1521
1522 /*
1523 * Propagate priority when a thread is blocked on POSIX
1524 * PI mutex.
1525 */
1526 static void
umtx_propagate_priority(struct thread * td)1527 umtx_propagate_priority(struct thread *td)
1528 {
1529 struct umtx_q *uq;
1530 struct umtx_pi *pi;
1531 int pri;
1532
1533 mtx_assert(&umtx_lock, MA_OWNED);
1534 pri = UPRI(td);
1535 uq = td->td_umtxq;
1536 pi = uq->uq_pi_blocked;
1537 if (pi == NULL)
1538 return;
1539 if (umtx_pi_check_loop(pi))
1540 return;
1541
1542 for (;;) {
1543 td = pi->pi_owner;
1544 if (td == NULL || td == curthread)
1545 return;
1546
1547 MPASS(td->td_proc != NULL);
1548 MPASS(td->td_proc->p_magic == P_MAGIC);
1549
1550 thread_lock(td);
1551 if (td->td_lend_user_pri > pri)
1552 sched_lend_user_prio(td, pri);
1553 else {
1554 thread_unlock(td);
1555 break;
1556 }
1557 thread_unlock(td);
1558
1559 /*
1560 * Pick up the lock that td is blocked on.
1561 */
1562 uq = td->td_umtxq;
1563 pi = uq->uq_pi_blocked;
1564 if (pi == NULL)
1565 break;
1566 /* Resort td on the list if needed. */
1567 umtx_pi_adjust_thread(pi, td);
1568 }
1569 }
1570
1571 /*
1572 * Unpropagate priority for a PI mutex when a thread blocked on
1573 * it is interrupted by signal or resumed by others.
1574 */
1575 static void
umtx_repropagate_priority(struct umtx_pi * pi)1576 umtx_repropagate_priority(struct umtx_pi *pi)
1577 {
1578 struct umtx_q *uq, *uq_owner;
1579 struct umtx_pi *pi2;
1580 int pri;
1581
1582 mtx_assert(&umtx_lock, MA_OWNED);
1583
1584 if (umtx_pi_check_loop(pi))
1585 return;
1586 while (pi != NULL && pi->pi_owner != NULL) {
1587 pri = PRI_MAX;
1588 uq_owner = pi->pi_owner->td_umtxq;
1589
1590 TAILQ_FOREACH(pi2, &uq_owner->uq_pi_contested, pi_link) {
1591 uq = TAILQ_FIRST(&pi2->pi_blocked);
1592 if (uq != NULL) {
1593 if (pri > UPRI(uq->uq_thread))
1594 pri = UPRI(uq->uq_thread);
1595 }
1596 }
1597
1598 if (pri > uq_owner->uq_inherited_pri)
1599 pri = uq_owner->uq_inherited_pri;
1600 thread_lock(pi->pi_owner);
1601 sched_lend_user_prio(pi->pi_owner, pri);
1602 thread_unlock(pi->pi_owner);
1603 if ((pi = uq_owner->uq_pi_blocked) != NULL)
1604 umtx_pi_adjust_thread(pi, uq_owner->uq_thread);
1605 }
1606 }
1607
1608 /*
1609 * Insert a PI mutex into owned list.
1610 */
1611 static void
umtx_pi_setowner(struct umtx_pi * pi,struct thread * owner)1612 umtx_pi_setowner(struct umtx_pi *pi, struct thread *owner)
1613 {
1614 struct umtx_q *uq_owner;
1615
1616 uq_owner = owner->td_umtxq;
1617 mtx_assert(&umtx_lock, MA_OWNED);
1618 MPASS(pi->pi_owner == NULL);
1619 pi->pi_owner = owner;
1620 TAILQ_INSERT_TAIL(&uq_owner->uq_pi_contested, pi, pi_link);
1621 }
1622
1623
1624 /*
1625 * Disown a PI mutex, and remove it from the owned list.
1626 */
1627 static void
umtx_pi_disown(struct umtx_pi * pi)1628 umtx_pi_disown(struct umtx_pi *pi)
1629 {
1630
1631 mtx_assert(&umtx_lock, MA_OWNED);
1632 TAILQ_REMOVE(&pi->pi_owner->td_umtxq->uq_pi_contested, pi, pi_link);
1633 pi->pi_owner = NULL;
1634 }
1635
1636 /*
1637 * Claim ownership of a PI mutex.
1638 */
1639 static int
umtx_pi_claim(struct umtx_pi * pi,struct thread * owner)1640 umtx_pi_claim(struct umtx_pi *pi, struct thread *owner)
1641 {
1642 struct umtx_q *uq;
1643 int pri;
1644
1645 mtx_lock(&umtx_lock);
1646 if (pi->pi_owner == owner) {
1647 mtx_unlock(&umtx_lock);
1648 return (0);
1649 }
1650
1651 if (pi->pi_owner != NULL) {
1652 /*
1653 * userland may have already messed the mutex, sigh.
1654 */
1655 mtx_unlock(&umtx_lock);
1656 return (EPERM);
1657 }
1658 umtx_pi_setowner(pi, owner);
1659 uq = TAILQ_FIRST(&pi->pi_blocked);
1660 if (uq != NULL) {
1661 pri = UPRI(uq->uq_thread);
1662 thread_lock(owner);
1663 if (pri < UPRI(owner))
1664 sched_lend_user_prio(owner, pri);
1665 thread_unlock(owner);
1666 }
1667 mtx_unlock(&umtx_lock);
1668 return (0);
1669 }
1670
1671 /*
1672 * Adjust a thread's order position in its blocked PI mutex,
1673 * this may result new priority propagating process.
1674 */
1675 void
umtx_pi_adjust(struct thread * td,u_char oldpri)1676 umtx_pi_adjust(struct thread *td, u_char oldpri)
1677 {
1678 struct umtx_q *uq;
1679 struct umtx_pi *pi;
1680
1681 uq = td->td_umtxq;
1682 mtx_lock(&umtx_lock);
1683 /*
1684 * Pick up the lock that td is blocked on.
1685 */
1686 pi = uq->uq_pi_blocked;
1687 if (pi != NULL) {
1688 umtx_pi_adjust_thread(pi, td);
1689 umtx_repropagate_priority(pi);
1690 }
1691 mtx_unlock(&umtx_lock);
1692 }
1693
1694 /*
1695 * Sleep on a PI mutex.
1696 */
1697 static int
umtxq_sleep_pi(struct umtx_q * uq,struct umtx_pi * pi,uint32_t owner,const char * wmesg,struct abs_timeout * timo,bool shared)1698 umtxq_sleep_pi(struct umtx_q *uq, struct umtx_pi *pi, uint32_t owner,
1699 const char *wmesg, struct abs_timeout *timo, bool shared)
1700 {
1701 struct thread *td, *td1;
1702 struct umtx_q *uq1;
1703 int error, pri;
1704 #ifdef INVARIANTS
1705 struct umtxq_chain *uc;
1706
1707 uc = umtxq_getchain(&pi->pi_key);
1708 #endif
1709 error = 0;
1710 td = uq->uq_thread;
1711 KASSERT(td == curthread, ("inconsistent uq_thread"));
1712 UMTXQ_LOCKED_ASSERT(umtxq_getchain(&uq->uq_key));
1713 KASSERT(uc->uc_busy != 0, ("umtx chain is not busy"));
1714 umtxq_insert(uq);
1715 mtx_lock(&umtx_lock);
1716 if (pi->pi_owner == NULL) {
1717 mtx_unlock(&umtx_lock);
1718 td1 = tdfind(owner, shared ? -1 : td->td_proc->p_pid);
1719 mtx_lock(&umtx_lock);
1720 if (td1 != NULL) {
1721 if (pi->pi_owner == NULL)
1722 umtx_pi_setowner(pi, td1);
1723 PROC_UNLOCK(td1->td_proc);
1724 }
1725 }
1726
1727 TAILQ_FOREACH(uq1, &pi->pi_blocked, uq_lockq) {
1728 pri = UPRI(uq1->uq_thread);
1729 if (pri > UPRI(td))
1730 break;
1731 }
1732
1733 if (uq1 != NULL)
1734 TAILQ_INSERT_BEFORE(uq1, uq, uq_lockq);
1735 else
1736 TAILQ_INSERT_TAIL(&pi->pi_blocked, uq, uq_lockq);
1737
1738 uq->uq_pi_blocked = pi;
1739 thread_lock(td);
1740 td->td_flags |= TDF_UPIBLOCKED;
1741 thread_unlock(td);
1742 umtx_propagate_priority(td);
1743 mtx_unlock(&umtx_lock);
1744 umtxq_unbusy(&uq->uq_key);
1745
1746 error = umtxq_sleep(uq, wmesg, timo);
1747 umtxq_remove(uq);
1748
1749 mtx_lock(&umtx_lock);
1750 uq->uq_pi_blocked = NULL;
1751 thread_lock(td);
1752 td->td_flags &= ~TDF_UPIBLOCKED;
1753 thread_unlock(td);
1754 TAILQ_REMOVE(&pi->pi_blocked, uq, uq_lockq);
1755 umtx_repropagate_priority(pi);
1756 mtx_unlock(&umtx_lock);
1757 umtxq_unlock(&uq->uq_key);
1758
1759 return (error);
1760 }
1761
1762 /*
1763 * Add reference count for a PI mutex.
1764 */
1765 static void
umtx_pi_ref(struct umtx_pi * pi)1766 umtx_pi_ref(struct umtx_pi *pi)
1767 {
1768
1769 UMTXQ_LOCKED_ASSERT(umtxq_getchain(&pi->pi_key));
1770 pi->pi_refcount++;
1771 }
1772
1773 /*
1774 * Decrease reference count for a PI mutex, if the counter
1775 * is decreased to zero, its memory space is freed.
1776 */
1777 static void
umtx_pi_unref(struct umtx_pi * pi)1778 umtx_pi_unref(struct umtx_pi *pi)
1779 {
1780 struct umtxq_chain *uc;
1781
1782 uc = umtxq_getchain(&pi->pi_key);
1783 UMTXQ_LOCKED_ASSERT(uc);
1784 KASSERT(pi->pi_refcount > 0, ("invalid reference count"));
1785 if (--pi->pi_refcount == 0) {
1786 mtx_lock(&umtx_lock);
1787 if (pi->pi_owner != NULL)
1788 umtx_pi_disown(pi);
1789 KASSERT(TAILQ_EMPTY(&pi->pi_blocked),
1790 ("blocked queue not empty"));
1791 mtx_unlock(&umtx_lock);
1792 TAILQ_REMOVE(&uc->uc_pi_list, pi, pi_hashlink);
1793 umtx_pi_free(pi);
1794 }
1795 }
1796
1797 /*
1798 * Find a PI mutex in hash table.
1799 */
1800 static struct umtx_pi *
umtx_pi_lookup(struct umtx_key * key)1801 umtx_pi_lookup(struct umtx_key *key)
1802 {
1803 struct umtxq_chain *uc;
1804 struct umtx_pi *pi;
1805
1806 uc = umtxq_getchain(key);
1807 UMTXQ_LOCKED_ASSERT(uc);
1808
1809 TAILQ_FOREACH(pi, &uc->uc_pi_list, pi_hashlink) {
1810 if (umtx_key_match(&pi->pi_key, key)) {
1811 return (pi);
1812 }
1813 }
1814 return (NULL);
1815 }
1816
1817 /*
1818 * Insert a PI mutex into hash table.
1819 */
1820 static inline void
umtx_pi_insert(struct umtx_pi * pi)1821 umtx_pi_insert(struct umtx_pi *pi)
1822 {
1823 struct umtxq_chain *uc;
1824
1825 uc = umtxq_getchain(&pi->pi_key);
1826 UMTXQ_LOCKED_ASSERT(uc);
1827 TAILQ_INSERT_TAIL(&uc->uc_pi_list, pi, pi_hashlink);
1828 }
1829
1830 /*
1831 * Lock a PI mutex.
1832 */
1833 static int
do_lock_pi(struct thread * td,struct umutex * m,uint32_t flags,struct _umtx_time * timeout,int try)1834 do_lock_pi(struct thread *td, struct umutex *m, uint32_t flags,
1835 struct _umtx_time *timeout, int try)
1836 {
1837 struct abs_timeout timo;
1838 struct umtx_q *uq;
1839 struct umtx_pi *pi, *new_pi;
1840 uint32_t id, old_owner, owner, old;
1841 int error, rv;
1842
1843 id = td->td_tid;
1844 uq = td->td_umtxq;
1845
1846 if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
1847 TYPE_PI_ROBUST_UMUTEX : TYPE_PI_UMUTEX, GET_SHARE(flags),
1848 &uq->uq_key)) != 0)
1849 return (error);
1850
1851 if (timeout != NULL)
1852 abs_timeout_init2(&timo, timeout);
1853
1854 umtxq_lock(&uq->uq_key);
1855 pi = umtx_pi_lookup(&uq->uq_key);
1856 if (pi == NULL) {
1857 new_pi = umtx_pi_alloc(M_NOWAIT);
1858 if (new_pi == NULL) {
1859 umtxq_unlock(&uq->uq_key);
1860 new_pi = umtx_pi_alloc(M_WAITOK);
1861 umtxq_lock(&uq->uq_key);
1862 pi = umtx_pi_lookup(&uq->uq_key);
1863 if (pi != NULL) {
1864 umtx_pi_free(new_pi);
1865 new_pi = NULL;
1866 }
1867 }
1868 if (new_pi != NULL) {
1869 new_pi->pi_key = uq->uq_key;
1870 umtx_pi_insert(new_pi);
1871 pi = new_pi;
1872 }
1873 }
1874 umtx_pi_ref(pi);
1875 umtxq_unlock(&uq->uq_key);
1876
1877 /*
1878 * Care must be exercised when dealing with umtx structure. It
1879 * can fault on any access.
1880 */
1881 for (;;) {
1882 /*
1883 * Try the uncontested case. This should be done in userland.
1884 */
1885 rv = casueword32(&m->m_owner, UMUTEX_UNOWNED, &owner, id);
1886 /* The address was invalid. */
1887 if (rv == -1) {
1888 error = EFAULT;
1889 break;
1890 }
1891 /* The acquire succeeded. */
1892 if (rv == 0) {
1893 MPASS(owner == UMUTEX_UNOWNED);
1894 error = 0;
1895 break;
1896 }
1897
1898 if (owner == UMUTEX_RB_NOTRECOV) {
1899 error = ENOTRECOVERABLE;
1900 break;
1901 }
1902
1903 /*
1904 * Avoid overwriting a possible error from sleep due
1905 * to the pending signal with suspension check result.
1906 */
1907 if (error == 0) {
1908 error = umtxq_check_susp(td, true);
1909 if (error != 0)
1910 break;
1911 }
1912
1913 /* If no one owns it but it is contested try to acquire it. */
1914 if (owner == UMUTEX_CONTESTED || owner == UMUTEX_RB_OWNERDEAD) {
1915 old_owner = owner;
1916 rv = casueword32(&m->m_owner, owner, &owner,
1917 id | UMUTEX_CONTESTED);
1918 /* The address was invalid. */
1919 if (rv == -1) {
1920 error = EFAULT;
1921 break;
1922 }
1923 if (rv == 1) {
1924 if (error == 0) {
1925 error = umtxq_check_susp(td, true);
1926 if (error != 0)
1927 break;
1928 }
1929
1930 /*
1931 * If this failed the lock could
1932 * changed, restart.
1933 */
1934 continue;
1935 }
1936
1937 MPASS(rv == 0);
1938 MPASS(owner == old_owner);
1939 umtxq_lock(&uq->uq_key);
1940 umtxq_busy(&uq->uq_key);
1941 error = umtx_pi_claim(pi, td);
1942 umtxq_unbusy(&uq->uq_key);
1943 umtxq_unlock(&uq->uq_key);
1944 if (error != 0) {
1945 /*
1946 * Since we're going to return an
1947 * error, restore the m_owner to its
1948 * previous, unowned state to avoid
1949 * compounding the problem.
1950 */
1951 (void)casuword32(&m->m_owner,
1952 id | UMUTEX_CONTESTED, old_owner);
1953 }
1954 if (error == 0 && old_owner == UMUTEX_RB_OWNERDEAD)
1955 error = EOWNERDEAD;
1956 break;
1957 }
1958
1959 if ((owner & ~UMUTEX_CONTESTED) == id) {
1960 error = EDEADLK;
1961 break;
1962 }
1963
1964 if (try != 0) {
1965 error = EBUSY;
1966 break;
1967 }
1968
1969 /*
1970 * If we caught a signal, we have retried and now
1971 * exit immediately.
1972 */
1973 if (error != 0)
1974 break;
1975
1976 umtxq_lock(&uq->uq_key);
1977 umtxq_busy(&uq->uq_key);
1978 umtxq_unlock(&uq->uq_key);
1979
1980 /*
1981 * Set the contested bit so that a release in user space
1982 * knows to use the system call for unlock. If this fails
1983 * either some one else has acquired the lock or it has been
1984 * released.
1985 */
1986 rv = casueword32(&m->m_owner, owner, &old, owner |
1987 UMUTEX_CONTESTED);
1988
1989 /* The address was invalid. */
1990 if (rv == -1) {
1991 umtxq_unbusy_unlocked(&uq->uq_key);
1992 error = EFAULT;
1993 break;
1994 }
1995 if (rv == 1) {
1996 umtxq_unbusy_unlocked(&uq->uq_key);
1997 error = umtxq_check_susp(td, true);
1998 if (error != 0)
1999 break;
2000
2001 /*
2002 * The lock changed and we need to retry or we
2003 * lost a race to the thread unlocking the
2004 * umtx. Note that the UMUTEX_RB_OWNERDEAD
2005 * value for owner is impossible there.
2006 */
2007 continue;
2008 }
2009
2010 umtxq_lock(&uq->uq_key);
2011
2012 /* We set the contested bit, sleep. */
2013 MPASS(old == owner);
2014 error = umtxq_sleep_pi(uq, pi, owner & ~UMUTEX_CONTESTED,
2015 "umtxpi", timeout == NULL ? NULL : &timo,
2016 (flags & USYNC_PROCESS_SHARED) != 0);
2017 if (error != 0)
2018 continue;
2019
2020 error = umtxq_check_susp(td, false);
2021 if (error != 0)
2022 break;
2023 }
2024
2025 umtxq_lock(&uq->uq_key);
2026 umtx_pi_unref(pi);
2027 umtxq_unlock(&uq->uq_key);
2028
2029 umtx_key_release(&uq->uq_key);
2030 return (error);
2031 }
2032
2033 /*
2034 * Unlock a PI mutex.
2035 */
2036 static int
do_unlock_pi(struct thread * td,struct umutex * m,uint32_t flags,bool rb)2037 do_unlock_pi(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
2038 {
2039 struct umtx_key key;
2040 struct umtx_q *uq_first, *uq_first2, *uq_me;
2041 struct umtx_pi *pi, *pi2;
2042 uint32_t id, new_owner, old, owner;
2043 int count, error, pri;
2044
2045 id = td->td_tid;
2046
2047 usrloop:
2048 /*
2049 * Make sure we own this mtx.
2050 */
2051 error = fueword32(&m->m_owner, &owner);
2052 if (error == -1)
2053 return (EFAULT);
2054
2055 if ((owner & ~UMUTEX_CONTESTED) != id)
2056 return (EPERM);
2057
2058 new_owner = umtx_unlock_val(flags, rb);
2059
2060 /* This should be done in userland */
2061 if ((owner & UMUTEX_CONTESTED) == 0) {
2062 error = casueword32(&m->m_owner, owner, &old, new_owner);
2063 if (error == -1)
2064 return (EFAULT);
2065 if (error == 1) {
2066 error = umtxq_check_susp(td, true);
2067 if (error != 0)
2068 return (error);
2069 goto usrloop;
2070 }
2071 if (old == owner)
2072 return (0);
2073 owner = old;
2074 }
2075
2076 /* We should only ever be in here for contested locks */
2077 if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
2078 TYPE_PI_ROBUST_UMUTEX : TYPE_PI_UMUTEX, GET_SHARE(flags),
2079 &key)) != 0)
2080 return (error);
2081
2082 umtxq_lock(&key);
2083 umtxq_busy(&key);
2084 count = umtxq_count_pi(&key, &uq_first);
2085 if (uq_first != NULL) {
2086 mtx_lock(&umtx_lock);
2087 pi = uq_first->uq_pi_blocked;
2088 KASSERT(pi != NULL, ("pi == NULL?"));
2089 if (pi->pi_owner != td && !(rb && pi->pi_owner == NULL)) {
2090 mtx_unlock(&umtx_lock);
2091 umtxq_unbusy(&key);
2092 umtxq_unlock(&key);
2093 umtx_key_release(&key);
2094 /* userland messed the mutex */
2095 return (EPERM);
2096 }
2097 uq_me = td->td_umtxq;
2098 if (pi->pi_owner == td)
2099 umtx_pi_disown(pi);
2100 /* get highest priority thread which is still sleeping. */
2101 uq_first = TAILQ_FIRST(&pi->pi_blocked);
2102 while (uq_first != NULL &&
2103 (uq_first->uq_flags & UQF_UMTXQ) == 0) {
2104 uq_first = TAILQ_NEXT(uq_first, uq_lockq);
2105 }
2106 pri = PRI_MAX;
2107 TAILQ_FOREACH(pi2, &uq_me->uq_pi_contested, pi_link) {
2108 uq_first2 = TAILQ_FIRST(&pi2->pi_blocked);
2109 if (uq_first2 != NULL) {
2110 if (pri > UPRI(uq_first2->uq_thread))
2111 pri = UPRI(uq_first2->uq_thread);
2112 }
2113 }
2114 thread_lock(td);
2115 sched_lend_user_prio(td, pri);
2116 thread_unlock(td);
2117 mtx_unlock(&umtx_lock);
2118 if (uq_first)
2119 umtxq_signal_thread(uq_first);
2120 } else {
2121 pi = umtx_pi_lookup(&key);
2122 /*
2123 * A umtx_pi can exist if a signal or timeout removed the
2124 * last waiter from the umtxq, but there is still
2125 * a thread in do_lock_pi() holding the umtx_pi.
2126 */
2127 if (pi != NULL) {
2128 /*
2129 * The umtx_pi can be unowned, such as when a thread
2130 * has just entered do_lock_pi(), allocated the
2131 * umtx_pi, and unlocked the umtxq.
2132 * If the current thread owns it, it must disown it.
2133 */
2134 mtx_lock(&umtx_lock);
2135 if (pi->pi_owner == td)
2136 umtx_pi_disown(pi);
2137 mtx_unlock(&umtx_lock);
2138 }
2139 }
2140 umtxq_unlock(&key);
2141
2142 /*
2143 * When unlocking the umtx, it must be marked as unowned if
2144 * there is zero or one thread only waiting for it.
2145 * Otherwise, it must be marked as contested.
2146 */
2147
2148 if (count > 1)
2149 new_owner |= UMUTEX_CONTESTED;
2150 again:
2151 error = casueword32(&m->m_owner, owner, &old, new_owner);
2152 if (error == 1) {
2153 error = umtxq_check_susp(td, false);
2154 if (error == 0)
2155 goto again;
2156 }
2157 umtxq_unbusy_unlocked(&key);
2158 umtx_key_release(&key);
2159 if (error == -1)
2160 return (EFAULT);
2161 if (error == 0 && old != owner)
2162 return (EINVAL);
2163 return (error);
2164 }
2165
2166 /*
2167 * Lock a PP mutex.
2168 */
2169 static int
do_lock_pp(struct thread * td,struct umutex * m,uint32_t flags,struct _umtx_time * timeout,int try)2170 do_lock_pp(struct thread *td, struct umutex *m, uint32_t flags,
2171 struct _umtx_time *timeout, int try)
2172 {
2173 struct abs_timeout timo;
2174 struct umtx_q *uq, *uq2;
2175 struct umtx_pi *pi;
2176 uint32_t ceiling;
2177 uint32_t owner, id;
2178 int error, pri, old_inherited_pri, su, rv;
2179
2180 id = td->td_tid;
2181 uq = td->td_umtxq;
2182 if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
2183 TYPE_PP_ROBUST_UMUTEX : TYPE_PP_UMUTEX, GET_SHARE(flags),
2184 &uq->uq_key)) != 0)
2185 return (error);
2186
2187 if (timeout != NULL)
2188 abs_timeout_init2(&timo, timeout);
2189
2190 su = (priv_check(td, PRIV_SCHED_RTPRIO) == 0);
2191 for (;;) {
2192 old_inherited_pri = uq->uq_inherited_pri;
2193 umtxq_lock(&uq->uq_key);
2194 umtxq_busy(&uq->uq_key);
2195 umtxq_unlock(&uq->uq_key);
2196
2197 rv = fueword32(&m->m_ceilings[0], &ceiling);
2198 if (rv == -1) {
2199 error = EFAULT;
2200 goto out;
2201 }
2202 ceiling = RTP_PRIO_MAX - ceiling;
2203 if (ceiling > RTP_PRIO_MAX) {
2204 error = EINVAL;
2205 goto out;
2206 }
2207
2208 mtx_lock(&umtx_lock);
2209 if (UPRI(td) < PRI_MIN_REALTIME + ceiling) {
2210 mtx_unlock(&umtx_lock);
2211 error = EINVAL;
2212 goto out;
2213 }
2214 if (su && PRI_MIN_REALTIME + ceiling < uq->uq_inherited_pri) {
2215 uq->uq_inherited_pri = PRI_MIN_REALTIME + ceiling;
2216 thread_lock(td);
2217 if (uq->uq_inherited_pri < UPRI(td))
2218 sched_lend_user_prio(td, uq->uq_inherited_pri);
2219 thread_unlock(td);
2220 }
2221 mtx_unlock(&umtx_lock);
2222
2223 rv = casueword32(&m->m_owner, UMUTEX_CONTESTED, &owner,
2224 id | UMUTEX_CONTESTED);
2225 /* The address was invalid. */
2226 if (rv == -1) {
2227 error = EFAULT;
2228 break;
2229 }
2230 if (rv == 0) {
2231 MPASS(owner == UMUTEX_CONTESTED);
2232 error = 0;
2233 break;
2234 }
2235 /* rv == 1 */
2236 if (owner == UMUTEX_RB_OWNERDEAD) {
2237 rv = casueword32(&m->m_owner, UMUTEX_RB_OWNERDEAD,
2238 &owner, id | UMUTEX_CONTESTED);
2239 if (rv == -1) {
2240 error = EFAULT;
2241 break;
2242 }
2243 if (rv == 0) {
2244 MPASS(owner == UMUTEX_RB_OWNERDEAD);
2245 error = EOWNERDEAD; /* success */
2246 break;
2247 }
2248
2249 /*
2250 * rv == 1, only check for suspension if we
2251 * did not already catched a signal. If we
2252 * get an error from the check, the same
2253 * condition is checked by the umtxq_sleep()
2254 * call below, so we should obliterate the
2255 * error to not skip the last loop iteration.
2256 */
2257 if (error == 0) {
2258 error = umtxq_check_susp(td, false);
2259 if (error == 0) {
2260 if (try != 0)
2261 error = EBUSY;
2262 else
2263 continue;
2264 }
2265 error = 0;
2266 }
2267 } else if (owner == UMUTEX_RB_NOTRECOV) {
2268 error = ENOTRECOVERABLE;
2269 }
2270
2271 if (try != 0)
2272 error = EBUSY;
2273
2274 /*
2275 * If we caught a signal, we have retried and now
2276 * exit immediately.
2277 */
2278 if (error != 0)
2279 break;
2280
2281 umtxq_lock(&uq->uq_key);
2282 umtxq_insert(uq);
2283 umtxq_unbusy(&uq->uq_key);
2284 error = umtxq_sleep(uq, "umtxpp", timeout == NULL ?
2285 NULL : &timo);
2286 umtxq_remove(uq);
2287 umtxq_unlock(&uq->uq_key);
2288
2289 mtx_lock(&umtx_lock);
2290 uq->uq_inherited_pri = old_inherited_pri;
2291 pri = PRI_MAX;
2292 TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
2293 uq2 = TAILQ_FIRST(&pi->pi_blocked);
2294 if (uq2 != NULL) {
2295 if (pri > UPRI(uq2->uq_thread))
2296 pri = UPRI(uq2->uq_thread);
2297 }
2298 }
2299 if (pri > uq->uq_inherited_pri)
2300 pri = uq->uq_inherited_pri;
2301 thread_lock(td);
2302 sched_lend_user_prio(td, pri);
2303 thread_unlock(td);
2304 mtx_unlock(&umtx_lock);
2305 }
2306
2307 if (error != 0 && error != EOWNERDEAD) {
2308 mtx_lock(&umtx_lock);
2309 uq->uq_inherited_pri = old_inherited_pri;
2310 pri = PRI_MAX;
2311 TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
2312 uq2 = TAILQ_FIRST(&pi->pi_blocked);
2313 if (uq2 != NULL) {
2314 if (pri > UPRI(uq2->uq_thread))
2315 pri = UPRI(uq2->uq_thread);
2316 }
2317 }
2318 if (pri > uq->uq_inherited_pri)
2319 pri = uq->uq_inherited_pri;
2320 thread_lock(td);
2321 sched_lend_user_prio(td, pri);
2322 thread_unlock(td);
2323 mtx_unlock(&umtx_lock);
2324 }
2325
2326 out:
2327 umtxq_unbusy_unlocked(&uq->uq_key);
2328 umtx_key_release(&uq->uq_key);
2329 return (error);
2330 }
2331
2332 /*
2333 * Unlock a PP mutex.
2334 */
2335 static int
do_unlock_pp(struct thread * td,struct umutex * m,uint32_t flags,bool rb)2336 do_unlock_pp(struct thread *td, struct umutex *m, uint32_t flags, bool rb)
2337 {
2338 struct umtx_key key;
2339 struct umtx_q *uq, *uq2;
2340 struct umtx_pi *pi;
2341 uint32_t id, owner, rceiling;
2342 int error, pri, new_inherited_pri, su;
2343
2344 id = td->td_tid;
2345 uq = td->td_umtxq;
2346 su = (priv_check(td, PRIV_SCHED_RTPRIO) == 0);
2347
2348 /*
2349 * Make sure we own this mtx.
2350 */
2351 error = fueword32(&m->m_owner, &owner);
2352 if (error == -1)
2353 return (EFAULT);
2354
2355 if ((owner & ~UMUTEX_CONTESTED) != id)
2356 return (EPERM);
2357
2358 error = copyin(&m->m_ceilings[1], &rceiling, sizeof(uint32_t));
2359 if (error != 0)
2360 return (error);
2361
2362 if (rceiling == -1)
2363 new_inherited_pri = PRI_MAX;
2364 else {
2365 rceiling = RTP_PRIO_MAX - rceiling;
2366 if (rceiling > RTP_PRIO_MAX)
2367 return (EINVAL);
2368 new_inherited_pri = PRI_MIN_REALTIME + rceiling;
2369 }
2370
2371 if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
2372 TYPE_PP_ROBUST_UMUTEX : TYPE_PP_UMUTEX, GET_SHARE(flags),
2373 &key)) != 0)
2374 return (error);
2375 umtxq_lock(&key);
2376 umtxq_busy(&key);
2377 umtxq_unlock(&key);
2378 /*
2379 * For priority protected mutex, always set unlocked state
2380 * to UMUTEX_CONTESTED, so that userland always enters kernel
2381 * to lock the mutex, it is necessary because thread priority
2382 * has to be adjusted for such mutex.
2383 */
2384 error = suword32(&m->m_owner, umtx_unlock_val(flags, rb) |
2385 UMUTEX_CONTESTED);
2386
2387 umtxq_lock(&key);
2388 if (error == 0)
2389 umtxq_signal(&key, 1);
2390 umtxq_unbusy(&key);
2391 umtxq_unlock(&key);
2392
2393 if (error == -1)
2394 error = EFAULT;
2395 else {
2396 mtx_lock(&umtx_lock);
2397 if (su != 0)
2398 uq->uq_inherited_pri = new_inherited_pri;
2399 pri = PRI_MAX;
2400 TAILQ_FOREACH(pi, &uq->uq_pi_contested, pi_link) {
2401 uq2 = TAILQ_FIRST(&pi->pi_blocked);
2402 if (uq2 != NULL) {
2403 if (pri > UPRI(uq2->uq_thread))
2404 pri = UPRI(uq2->uq_thread);
2405 }
2406 }
2407 if (pri > uq->uq_inherited_pri)
2408 pri = uq->uq_inherited_pri;
2409 thread_lock(td);
2410 sched_lend_user_prio(td, pri);
2411 thread_unlock(td);
2412 mtx_unlock(&umtx_lock);
2413 }
2414 umtx_key_release(&key);
2415 return (error);
2416 }
2417
2418 static int
do_set_ceiling(struct thread * td,struct umutex * m,uint32_t ceiling,uint32_t * old_ceiling)2419 do_set_ceiling(struct thread *td, struct umutex *m, uint32_t ceiling,
2420 uint32_t *old_ceiling)
2421 {
2422 struct umtx_q *uq;
2423 uint32_t flags, id, owner, save_ceiling;
2424 int error, rv, rv1;
2425
2426 error = fueword32(&m->m_flags, &flags);
2427 if (error == -1)
2428 return (EFAULT);
2429 if ((flags & UMUTEX_PRIO_PROTECT) == 0)
2430 return (EINVAL);
2431 if (ceiling > RTP_PRIO_MAX)
2432 return (EINVAL);
2433 id = td->td_tid;
2434 uq = td->td_umtxq;
2435 if ((error = umtx_key_get(m, (flags & UMUTEX_ROBUST) != 0 ?
2436 TYPE_PP_ROBUST_UMUTEX : TYPE_PP_UMUTEX, GET_SHARE(flags),
2437 &uq->uq_key)) != 0)
2438 return (error);
2439 for (;;) {
2440 umtxq_lock(&uq->uq_key);
2441 umtxq_busy(&uq->uq_key);
2442 umtxq_unlock(&uq->uq_key);
2443
2444 rv = fueword32(&m->m_ceilings[0], &save_ceiling);
2445 if (rv == -1) {
2446 error = EFAULT;
2447 break;
2448 }
2449
2450 rv = casueword32(&m->m_owner, UMUTEX_CONTESTED, &owner,
2451 id | UMUTEX_CONTESTED);
2452 if (rv == -1) {
2453 error = EFAULT;
2454 break;
2455 }
2456
2457 if (rv == 0) {
2458 MPASS(owner == UMUTEX_CONTESTED);
2459 rv = suword32(&m->m_ceilings[0], ceiling);
2460 rv1 = suword32(&m->m_owner, UMUTEX_CONTESTED);
2461 error = (rv == 0 && rv1 == 0) ? 0: EFAULT;
2462 break;
2463 }
2464
2465 if ((owner & ~UMUTEX_CONTESTED) == id) {
2466 rv = suword32(&m->m_ceilings[0], ceiling);
2467 error = rv == 0 ? 0 : EFAULT;
2468 break;
2469 }
2470
2471 if (owner == UMUTEX_RB_OWNERDEAD) {
2472 error = EOWNERDEAD;
2473 break;
2474 } else if (owner == UMUTEX_RB_NOTRECOV) {
2475 error = ENOTRECOVERABLE;
2476 break;
2477 }
2478
2479 /*
2480 * If we caught a signal, we have retried and now
2481 * exit immediately.
2482 */
2483 if (error != 0)
2484 break;
2485
2486 /*
2487 * We set the contested bit, sleep. Otherwise the lock changed
2488 * and we need to retry or we lost a race to the thread
2489 * unlocking the umtx.
2490 */
2491 umtxq_lock(&uq->uq_key);
2492 umtxq_insert(uq);
2493 umtxq_unbusy(&uq->uq_key);
2494 error = umtxq_sleep(uq, "umtxpp", NULL);
2495 umtxq_remove(uq);
2496 umtxq_unlock(&uq->uq_key);
2497 }
2498 umtxq_lock(&uq->uq_key);
2499 if (error == 0)
2500 umtxq_signal(&uq->uq_key, INT_MAX);
2501 umtxq_unbusy(&uq->uq_key);
2502 umtxq_unlock(&uq->uq_key);
2503 umtx_key_release(&uq->uq_key);
2504 if (error == 0 && old_ceiling != NULL) {
2505 rv = suword32(old_ceiling, save_ceiling);
2506 error = rv == 0 ? 0 : EFAULT;
2507 }
2508 return (error);
2509 }
2510
2511 /*
2512 * Lock a userland POSIX mutex.
2513 */
2514 static int
do_lock_umutex(struct thread * td,struct umutex * m,struct _umtx_time * timeout,int mode)2515 do_lock_umutex(struct thread *td, struct umutex *m,
2516 struct _umtx_time *timeout, int mode)
2517 {
2518 uint32_t flags;
2519 int error;
2520
2521 error = fueword32(&m->m_flags, &flags);
2522 if (error == -1)
2523 return (EFAULT);
2524
2525 switch (flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT)) {
2526 case 0:
2527 error = do_lock_normal(td, m, flags, timeout, mode);
2528 break;
2529 case UMUTEX_PRIO_INHERIT:
2530 error = do_lock_pi(td, m, flags, timeout, mode);
2531 break;
2532 case UMUTEX_PRIO_PROTECT:
2533 error = do_lock_pp(td, m, flags, timeout, mode);
2534 break;
2535 default:
2536 return (EINVAL);
2537 }
2538 if (timeout == NULL) {
2539 if (error == EINTR && mode != _UMUTEX_WAIT)
2540 error = ERESTART;
2541 } else {
2542 /* Timed-locking is not restarted. */
2543 if (error == ERESTART)
2544 error = EINTR;
2545 }
2546 return (error);
2547 }
2548
2549 /*
2550 * Unlock a userland POSIX mutex.
2551 */
2552 static int
do_unlock_umutex(struct thread * td,struct umutex * m,bool rb)2553 do_unlock_umutex(struct thread *td, struct umutex *m, bool rb)
2554 {
2555 uint32_t flags;
2556 int error;
2557
2558 error = fueword32(&m->m_flags, &flags);
2559 if (error == -1)
2560 return (EFAULT);
2561
2562 switch (flags & (UMUTEX_PRIO_INHERIT | UMUTEX_PRIO_PROTECT)) {
2563 case 0:
2564 return (do_unlock_normal(td, m, flags, rb));
2565 case UMUTEX_PRIO_INHERIT:
2566 return (do_unlock_pi(td, m, flags, rb));
2567 case UMUTEX_PRIO_PROTECT:
2568 return (do_unlock_pp(td, m, flags, rb));
2569 }
2570
2571 return (EINVAL);
2572 }
2573
2574 static int
do_cv_wait(struct thread * td,struct ucond * cv,struct umutex * m,struct timespec * timeout,u_long wflags)2575 do_cv_wait(struct thread *td, struct ucond *cv, struct umutex *m,
2576 struct timespec *timeout, u_long wflags)
2577 {
2578 struct abs_timeout timo;
2579 struct umtx_q *uq;
2580 uint32_t flags, clockid, hasw;
2581 int error;
2582
2583 uq = td->td_umtxq;
2584 error = fueword32(&cv->c_flags, &flags);
2585 if (error == -1)
2586 return (EFAULT);
2587 error = umtx_key_get(cv, TYPE_CV, GET_SHARE(flags), &uq->uq_key);
2588 if (error != 0)
2589 return (error);
2590
2591 if ((wflags & CVWAIT_CLOCKID) != 0) {
2592 error = fueword32(&cv->c_clockid, &clockid);
2593 if (error == -1) {
2594 umtx_key_release(&uq->uq_key);
2595 return (EFAULT);
2596 }
2597 if (clockid < CLOCK_REALTIME ||
2598 clockid >= CLOCK_THREAD_CPUTIME_ID) {
2599 /* hmm, only HW clock id will work. */
2600 umtx_key_release(&uq->uq_key);
2601 return (EINVAL);
2602 }
2603 } else {
2604 clockid = CLOCK_REALTIME;
2605 }
2606
2607 umtxq_lock(&uq->uq_key);
2608 umtxq_busy(&uq->uq_key);
2609 umtxq_insert(uq);
2610 umtxq_unlock(&uq->uq_key);
2611
2612 /*
2613 * Set c_has_waiters to 1 before releasing user mutex, also
2614 * don't modify cache line when unnecessary.
2615 */
2616 error = fueword32(&cv->c_has_waiters, &hasw);
2617 if (error == 0 && hasw == 0)
2618 suword32(&cv->c_has_waiters, 1);
2619
2620 umtxq_unbusy_unlocked(&uq->uq_key);
2621
2622 error = do_unlock_umutex(td, m, false);
2623
2624 if (timeout != NULL)
2625 abs_timeout_init(&timo, clockid, (wflags & CVWAIT_ABSTIME) != 0,
2626 timeout);
2627
2628 umtxq_lock(&uq->uq_key);
2629 if (error == 0) {
2630 error = umtxq_sleep(uq, "ucond", timeout == NULL ?
2631 NULL : &timo);
2632 }
2633
2634 if ((uq->uq_flags & UQF_UMTXQ) == 0)
2635 error = 0;
2636 else {
2637 /*
2638 * This must be timeout,interrupted by signal or
2639 * surprious wakeup, clear c_has_waiter flag when
2640 * necessary.
2641 */
2642 umtxq_busy(&uq->uq_key);
2643 if ((uq->uq_flags & UQF_UMTXQ) != 0) {
2644 int oldlen = uq->uq_cur_queue->length;
2645 umtxq_remove(uq);
2646 if (oldlen == 1) {
2647 umtxq_unlock(&uq->uq_key);
2648 suword32(&cv->c_has_waiters, 0);
2649 umtxq_lock(&uq->uq_key);
2650 }
2651 }
2652 umtxq_unbusy(&uq->uq_key);
2653 if (error == ERESTART)
2654 error = EINTR;
2655 }
2656
2657 umtxq_unlock(&uq->uq_key);
2658 umtx_key_release(&uq->uq_key);
2659 return (error);
2660 }
2661
2662 /*
2663 * Signal a userland condition variable.
2664 */
2665 static int
do_cv_signal(struct thread * td,struct ucond * cv)2666 do_cv_signal(struct thread *td, struct ucond *cv)
2667 {
2668 struct umtx_key key;
2669 int error, cnt, nwake;
2670 uint32_t flags;
2671
2672 error = fueword32(&cv->c_flags, &flags);
2673 if (error == -1)
2674 return (EFAULT);
2675 if ((error = umtx_key_get(cv, TYPE_CV, GET_SHARE(flags), &key)) != 0)
2676 return (error);
2677 umtxq_lock(&key);
2678 umtxq_busy(&key);
2679 cnt = umtxq_count(&key);
2680 nwake = umtxq_signal(&key, 1);
2681 if (cnt <= nwake) {
2682 umtxq_unlock(&key);
2683 error = suword32(&cv->c_has_waiters, 0);
2684 if (error == -1)
2685 error = EFAULT;
2686 umtxq_lock(&key);
2687 }
2688 umtxq_unbusy(&key);
2689 umtxq_unlock(&key);
2690 umtx_key_release(&key);
2691 return (error);
2692 }
2693
2694 static int
do_cv_broadcast(struct thread * td,struct ucond * cv)2695 do_cv_broadcast(struct thread *td, struct ucond *cv)
2696 {
2697 struct umtx_key key;
2698 int error;
2699 uint32_t flags;
2700
2701 error = fueword32(&cv->c_flags, &flags);
2702 if (error == -1)
2703 return (EFAULT);
2704 if ((error = umtx_key_get(cv, TYPE_CV, GET_SHARE(flags), &key)) != 0)
2705 return (error);
2706
2707 umtxq_lock(&key);
2708 umtxq_busy(&key);
2709 umtxq_signal(&key, INT_MAX);
2710 umtxq_unlock(&key);
2711
2712 error = suword32(&cv->c_has_waiters, 0);
2713 if (error == -1)
2714 error = EFAULT;
2715
2716 umtxq_unbusy_unlocked(&key);
2717
2718 umtx_key_release(&key);
2719 return (error);
2720 }
2721
2722 static int
do_rw_rdlock(struct thread * td,struct urwlock * rwlock,long fflag,struct _umtx_time * timeout)2723 do_rw_rdlock(struct thread *td, struct urwlock *rwlock, long fflag,
2724 struct _umtx_time *timeout)
2725 {
2726 struct abs_timeout timo;
2727 struct umtx_q *uq;
2728 uint32_t flags, wrflags;
2729 int32_t state, oldstate;
2730 int32_t blocked_readers;
2731 int error, error1, rv;
2732
2733 uq = td->td_umtxq;
2734 error = fueword32(&rwlock->rw_flags, &flags);
2735 if (error == -1)
2736 return (EFAULT);
2737 error = umtx_key_get(rwlock, TYPE_RWLOCK, GET_SHARE(flags), &uq->uq_key);
2738 if (error != 0)
2739 return (error);
2740
2741 if (timeout != NULL)
2742 abs_timeout_init2(&timo, timeout);
2743
2744 wrflags = URWLOCK_WRITE_OWNER;
2745 if (!(fflag & URWLOCK_PREFER_READER) && !(flags & URWLOCK_PREFER_READER))
2746 wrflags |= URWLOCK_WRITE_WAITERS;
2747
2748 for (;;) {
2749 rv = fueword32(&rwlock->rw_state, &state);
2750 if (rv == -1) {
2751 umtx_key_release(&uq->uq_key);
2752 return (EFAULT);
2753 }
2754
2755 /* try to lock it */
2756 while (!(state & wrflags)) {
2757 if (__predict_false(URWLOCK_READER_COUNT(state) ==
2758 URWLOCK_MAX_READERS)) {
2759 umtx_key_release(&uq->uq_key);
2760 return (EAGAIN);
2761 }
2762 rv = casueword32(&rwlock->rw_state, state,
2763 &oldstate, state + 1);
2764 if (rv == -1) {
2765 umtx_key_release(&uq->uq_key);
2766 return (EFAULT);
2767 }
2768 if (rv == 0) {
2769 MPASS(oldstate == state);
2770 umtx_key_release(&uq->uq_key);
2771 return (0);
2772 }
2773 error = umtxq_check_susp(td, true);
2774 if (error != 0)
2775 break;
2776 state = oldstate;
2777 }
2778
2779 if (error)
2780 break;
2781
2782 /* grab monitor lock */
2783 umtxq_lock(&uq->uq_key);
2784 umtxq_busy(&uq->uq_key);
2785 umtxq_unlock(&uq->uq_key);
2786
2787 /*
2788 * re-read the state, in case it changed between the try-lock above
2789 * and the check below
2790 */
2791 rv = fueword32(&rwlock->rw_state, &state);
2792 if (rv == -1)
2793 error = EFAULT;
2794
2795 /* set read contention bit */
2796 while (error == 0 && (state & wrflags) &&
2797 !(state & URWLOCK_READ_WAITERS)) {
2798 rv = casueword32(&rwlock->rw_state, state,
2799 &oldstate, state | URWLOCK_READ_WAITERS);
2800 if (rv == -1) {
2801 error = EFAULT;
2802 break;
2803 }
2804 if (rv == 0) {
2805 MPASS(oldstate == state);
2806 goto sleep;
2807 }
2808 state = oldstate;
2809 error = umtxq_check_susp(td, false);
2810 if (error != 0)
2811 break;
2812 }
2813 if (error != 0) {
2814 umtxq_unbusy_unlocked(&uq->uq_key);
2815 break;
2816 }
2817
2818 /* state is changed while setting flags, restart */
2819 if (!(state & wrflags)) {
2820 umtxq_unbusy_unlocked(&uq->uq_key);
2821 error = umtxq_check_susp(td, true);
2822 if (error != 0)
2823 break;
2824 continue;
2825 }
2826
2827 sleep:
2828 /*
2829 * Contention bit is set, before sleeping, increase
2830 * read waiter count.
2831 */
2832 rv = fueword32(&rwlock->rw_blocked_readers,
2833 &blocked_readers);
2834 if (rv == -1) {
2835 umtxq_unbusy_unlocked(&uq->uq_key);
2836 error = EFAULT;
2837 break;
2838 }
2839 suword32(&rwlock->rw_blocked_readers, blocked_readers+1);
2840
2841 while (state & wrflags) {
2842 umtxq_lock(&uq->uq_key);
2843 umtxq_insert(uq);
2844 umtxq_unbusy(&uq->uq_key);
2845
2846 error = umtxq_sleep(uq, "urdlck", timeout == NULL ?
2847 NULL : &timo);
2848
2849 umtxq_busy(&uq->uq_key);
2850 umtxq_remove(uq);
2851 umtxq_unlock(&uq->uq_key);
2852 if (error)
2853 break;
2854 rv = fueword32(&rwlock->rw_state, &state);
2855 if (rv == -1) {
2856 error = EFAULT;
2857 break;
2858 }
2859 }
2860
2861 /* decrease read waiter count, and may clear read contention bit */
2862 rv = fueword32(&rwlock->rw_blocked_readers,
2863 &blocked_readers);
2864 if (rv == -1) {
2865 umtxq_unbusy_unlocked(&uq->uq_key);
2866 error = EFAULT;
2867 break;
2868 }
2869 suword32(&rwlock->rw_blocked_readers, blocked_readers-1);
2870 if (blocked_readers == 1) {
2871 rv = fueword32(&rwlock->rw_state, &state);
2872 if (rv == -1) {
2873 umtxq_unbusy_unlocked(&uq->uq_key);
2874 error = EFAULT;
2875 break;
2876 }
2877 for (;;) {
2878 rv = casueword32(&rwlock->rw_state, state,
2879 &oldstate, state & ~URWLOCK_READ_WAITERS);
2880 if (rv == -1) {
2881 error = EFAULT;
2882 break;
2883 }
2884 if (rv == 0) {
2885 MPASS(oldstate == state);
2886 break;
2887 }
2888 state = oldstate;
2889 error1 = umtxq_check_susp(td, false);
2890 if (error1 != 0) {
2891 if (error == 0)
2892 error = error1;
2893 break;
2894 }
2895 }
2896 }
2897
2898 umtxq_unbusy_unlocked(&uq->uq_key);
2899 if (error != 0)
2900 break;
2901 }
2902 umtx_key_release(&uq->uq_key);
2903 if (error == ERESTART)
2904 error = EINTR;
2905 return (error);
2906 }
2907
2908 static int
do_rw_wrlock(struct thread * td,struct urwlock * rwlock,struct _umtx_time * timeout)2909 do_rw_wrlock(struct thread *td, struct urwlock *rwlock, struct _umtx_time *timeout)
2910 {
2911 struct abs_timeout timo;
2912 struct umtx_q *uq;
2913 uint32_t flags;
2914 int32_t state, oldstate;
2915 int32_t blocked_writers;
2916 int32_t blocked_readers;
2917 int error, error1, rv;
2918
2919 uq = td->td_umtxq;
2920 error = fueword32(&rwlock->rw_flags, &flags);
2921 if (error == -1)
2922 return (EFAULT);
2923 error = umtx_key_get(rwlock, TYPE_RWLOCK, GET_SHARE(flags), &uq->uq_key);
2924 if (error != 0)
2925 return (error);
2926
2927 if (timeout != NULL)
2928 abs_timeout_init2(&timo, timeout);
2929
2930 blocked_readers = 0;
2931 for (;;) {
2932 rv = fueword32(&rwlock->rw_state, &state);
2933 if (rv == -1) {
2934 umtx_key_release(&uq->uq_key);
2935 return (EFAULT);
2936 }
2937 while ((state & URWLOCK_WRITE_OWNER) == 0 &&
2938 URWLOCK_READER_COUNT(state) == 0) {
2939 rv = casueword32(&rwlock->rw_state, state,
2940 &oldstate, state | URWLOCK_WRITE_OWNER);
2941 if (rv == -1) {
2942 umtx_key_release(&uq->uq_key);
2943 return (EFAULT);
2944 }
2945 if (rv == 0) {
2946 MPASS(oldstate == state);
2947 umtx_key_release(&uq->uq_key);
2948 return (0);
2949 }
2950 state = oldstate;
2951 error = umtxq_check_susp(td, true);
2952 if (error != 0)
2953 break;
2954 }
2955
2956 if (error) {
2957 if ((state & (URWLOCK_WRITE_OWNER |
2958 URWLOCK_WRITE_WAITERS)) == 0 &&
2959 blocked_readers != 0) {
2960 umtxq_lock(&uq->uq_key);
2961 umtxq_busy(&uq->uq_key);
2962 umtxq_signal_queue(&uq->uq_key, INT_MAX,
2963 UMTX_SHARED_QUEUE);
2964 umtxq_unbusy(&uq->uq_key);
2965 umtxq_unlock(&uq->uq_key);
2966 }
2967
2968 break;
2969 }
2970
2971 /* grab monitor lock */
2972 umtxq_lock(&uq->uq_key);
2973 umtxq_busy(&uq->uq_key);
2974 umtxq_unlock(&uq->uq_key);
2975
2976 /*
2977 * Re-read the state, in case it changed between the
2978 * try-lock above and the check below.
2979 */
2980 rv = fueword32(&rwlock->rw_state, &state);
2981 if (rv == -1)
2982 error = EFAULT;
2983
2984 while (error == 0 && ((state & URWLOCK_WRITE_OWNER) ||
2985 URWLOCK_READER_COUNT(state) != 0) &&
2986 (state & URWLOCK_WRITE_WAITERS) == 0) {
2987 rv = casueword32(&rwlock->rw_state, state,
2988 &oldstate, state | URWLOCK_WRITE_WAITERS);
2989 if (rv == -1) {
2990 error = EFAULT;
2991 break;
2992 }
2993 if (rv == 0) {
2994 MPASS(oldstate == state);
2995 goto sleep;
2996 }
2997 state = oldstate;
2998 error = umtxq_check_susp(td, false);
2999 if (error != 0)
3000 break;
3001 }
3002 if (error != 0) {
3003 umtxq_unbusy_unlocked(&uq->uq_key);
3004 break;
3005 }
3006
3007 if ((state & URWLOCK_WRITE_OWNER) == 0 &&
3008 URWLOCK_READER_COUNT(state) == 0) {
3009 umtxq_unbusy_unlocked(&uq->uq_key);
3010 error = umtxq_check_susp(td, false);
3011 if (error != 0)
3012 break;
3013 continue;
3014 }
3015 sleep:
3016 rv = fueword32(&rwlock->rw_blocked_writers,
3017 &blocked_writers);
3018 if (rv == -1) {
3019 umtxq_unbusy_unlocked(&uq->uq_key);
3020 error = EFAULT;
3021 break;
3022 }
3023 suword32(&rwlock->rw_blocked_writers, blocked_writers + 1);
3024
3025 while ((state & URWLOCK_WRITE_OWNER) ||
3026 URWLOCK_READER_COUNT(state) != 0) {
3027 umtxq_lock(&uq->uq_key);
3028 umtxq_insert_queue(uq, UMTX_EXCLUSIVE_QUEUE);
3029 umtxq_unbusy(&uq->uq_key);
3030
3031 error = umtxq_sleep(uq, "uwrlck", timeout == NULL ?
3032 NULL : &timo);
3033
3034 umtxq_busy(&uq->uq_key);
3035 umtxq_remove_queue(uq, UMTX_EXCLUSIVE_QUEUE);
3036 umtxq_unlock(&uq->uq_key);
3037 if (error)
3038 break;
3039 rv = fueword32(&rwlock->rw_state, &state);
3040 if (rv == -1) {
3041 error = EFAULT;
3042 break;
3043 }
3044 }
3045
3046 rv = fueword32(&rwlock->rw_blocked_writers,
3047 &blocked_writers);
3048 if (rv == -1) {
3049 umtxq_unbusy_unlocked(&uq->uq_key);
3050 error = EFAULT;
3051 break;
3052 }
3053 suword32(&rwlock->rw_blocked_writers, blocked_writers-1);
3054 if (blocked_writers == 1) {
3055 rv = fueword32(&rwlock->rw_state, &state);
3056 if (rv == -1) {
3057 umtxq_unbusy_unlocked(&uq->uq_key);
3058 error = EFAULT;
3059 break;
3060 }
3061 for (;;) {
3062 rv = casueword32(&rwlock->rw_state, state,
3063 &oldstate, state & ~URWLOCK_WRITE_WAITERS);
3064 if (rv == -1) {
3065 error = EFAULT;
3066 break;
3067 }
3068 if (rv == 0) {
3069 MPASS(oldstate == state);
3070 break;
3071 }
3072 state = oldstate;
3073 error1 = umtxq_check_susp(td, false);
3074 /*
3075 * We are leaving the URWLOCK_WRITE_WAITERS
3076 * behind, but this should not harm the
3077 * correctness.
3078 */
3079 if (error1 != 0) {
3080 if (error == 0)
3081 error = error1;
3082 break;
3083 }
3084 }
3085 rv = fueword32(&rwlock->rw_blocked_readers,
3086 &blocked_readers);
3087 if (rv == -1) {
3088 umtxq_unbusy_unlocked(&uq->uq_key);
3089 error = EFAULT;
3090 break;
3091 }
3092 } else
3093 blocked_readers = 0;
3094
3095 umtxq_unbusy_unlocked(&uq->uq_key);
3096 }
3097
3098 umtx_key_release(&uq->uq_key);
3099 if (error == ERESTART)
3100 error = EINTR;
3101 return (error);
3102 }
3103
3104 static int
do_rw_unlock(struct thread * td,struct urwlock * rwlock)3105 do_rw_unlock(struct thread *td, struct urwlock *rwlock)
3106 {
3107 struct umtx_q *uq;
3108 uint32_t flags;
3109 int32_t state, oldstate;
3110 int error, rv, q, count;
3111
3112 uq = td->td_umtxq;
3113 error = fueword32(&rwlock->rw_flags, &flags);
3114 if (error == -1)
3115 return (EFAULT);
3116 error = umtx_key_get(rwlock, TYPE_RWLOCK, GET_SHARE(flags), &uq->uq_key);
3117 if (error != 0)
3118 return (error);
3119
3120 error = fueword32(&rwlock->rw_state, &state);
3121 if (error == -1) {
3122 error = EFAULT;
3123 goto out;
3124 }
3125 if (state & URWLOCK_WRITE_OWNER) {
3126 for (;;) {
3127 rv = casueword32(&rwlock->rw_state, state,
3128 &oldstate, state & ~URWLOCK_WRITE_OWNER);
3129 if (rv == -1) {
3130 error = EFAULT;
3131 goto out;
3132 }
3133 if (rv == 1) {
3134 state = oldstate;
3135 if (!(oldstate & URWLOCK_WRITE_OWNER)) {
3136 error = EPERM;
3137 goto out;
3138 }
3139 error = umtxq_check_susp(td, true);
3140 if (error != 0)
3141 goto out;
3142 } else
3143 break;
3144 }
3145 } else if (URWLOCK_READER_COUNT(state) != 0) {
3146 for (;;) {
3147 rv = casueword32(&rwlock->rw_state, state,
3148 &oldstate, state - 1);
3149 if (rv == -1) {
3150 error = EFAULT;
3151 goto out;
3152 }
3153 if (rv == 1) {
3154 state = oldstate;
3155 if (URWLOCK_READER_COUNT(oldstate) == 0) {
3156 error = EPERM;
3157 goto out;
3158 }
3159 error = umtxq_check_susp(td, true);
3160 if (error != 0)
3161 goto out;
3162 } else
3163 break;
3164 }
3165 } else {
3166 error = EPERM;
3167 goto out;
3168 }
3169
3170 count = 0;
3171
3172 if (!(flags & URWLOCK_PREFER_READER)) {
3173 if (state & URWLOCK_WRITE_WAITERS) {
3174 count = 1;
3175 q = UMTX_EXCLUSIVE_QUEUE;
3176 } else if (state & URWLOCK_READ_WAITERS) {
3177 count = INT_MAX;
3178 q = UMTX_SHARED_QUEUE;
3179 }
3180 } else {
3181 if (state & URWLOCK_READ_WAITERS) {
3182 count = INT_MAX;
3183 q = UMTX_SHARED_QUEUE;
3184 } else if (state & URWLOCK_WRITE_WAITERS) {
3185 count = 1;
3186 q = UMTX_EXCLUSIVE_QUEUE;
3187 }
3188 }
3189
3190 if (count) {
3191 umtxq_lock(&uq->uq_key);
3192 umtxq_busy(&uq->uq_key);
3193 umtxq_signal_queue(&uq->uq_key, count, q);
3194 umtxq_unbusy(&uq->uq_key);
3195 umtxq_unlock(&uq->uq_key);
3196 }
3197 out:
3198 umtx_key_release(&uq->uq_key);
3199 return (error);
3200 }
3201
3202 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
3203 static int
do_sem_wait(struct thread * td,struct _usem * sem,struct _umtx_time * timeout)3204 do_sem_wait(struct thread *td, struct _usem *sem, struct _umtx_time *timeout)
3205 {
3206 struct abs_timeout timo;
3207 struct umtx_q *uq;
3208 uint32_t flags, count, count1;
3209 int error, rv, rv1;
3210
3211 uq = td->td_umtxq;
3212 error = fueword32(&sem->_flags, &flags);
3213 if (error == -1)
3214 return (EFAULT);
3215 error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &uq->uq_key);
3216 if (error != 0)
3217 return (error);
3218
3219 if (timeout != NULL)
3220 abs_timeout_init2(&timo, timeout);
3221
3222 again:
3223 umtxq_lock(&uq->uq_key);
3224 umtxq_busy(&uq->uq_key);
3225 umtxq_insert(uq);
3226 umtxq_unlock(&uq->uq_key);
3227 rv = casueword32(&sem->_has_waiters, 0, &count1, 1);
3228 if (rv == 0)
3229 rv1 = fueword32(&sem->_count, &count);
3230 if (rv == -1 || (rv == 0 && (rv1 == -1 || count != 0)) ||
3231 (rv == 1 && count1 == 0)) {
3232 umtxq_lock(&uq->uq_key);
3233 umtxq_unbusy(&uq->uq_key);
3234 umtxq_remove(uq);
3235 umtxq_unlock(&uq->uq_key);
3236 if (rv == 1) {
3237 rv = umtxq_check_susp(td, true);
3238 if (rv == 0)
3239 goto again;
3240 error = rv;
3241 goto out;
3242 }
3243 if (rv == 0)
3244 rv = rv1;
3245 error = rv == -1 ? EFAULT : 0;
3246 goto out;
3247 }
3248 umtxq_lock(&uq->uq_key);
3249 umtxq_unbusy(&uq->uq_key);
3250
3251 error = umtxq_sleep(uq, "usem", timeout == NULL ? NULL : &timo);
3252
3253 if ((uq->uq_flags & UQF_UMTXQ) == 0)
3254 error = 0;
3255 else {
3256 umtxq_remove(uq);
3257 /* A relative timeout cannot be restarted. */
3258 if (error == ERESTART && timeout != NULL &&
3259 (timeout->_flags & UMTX_ABSTIME) == 0)
3260 error = EINTR;
3261 }
3262 umtxq_unlock(&uq->uq_key);
3263 out:
3264 umtx_key_release(&uq->uq_key);
3265 return (error);
3266 }
3267
3268 /*
3269 * Signal a userland semaphore.
3270 */
3271 static int
do_sem_wake(struct thread * td,struct _usem * sem)3272 do_sem_wake(struct thread *td, struct _usem *sem)
3273 {
3274 struct umtx_key key;
3275 int error, cnt;
3276 uint32_t flags;
3277
3278 error = fueword32(&sem->_flags, &flags);
3279 if (error == -1)
3280 return (EFAULT);
3281 if ((error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &key)) != 0)
3282 return (error);
3283 umtxq_lock(&key);
3284 umtxq_busy(&key);
3285 cnt = umtxq_count(&key);
3286 if (cnt > 0) {
3287 /*
3288 * Check if count is greater than 0, this means the memory is
3289 * still being referenced by user code, so we can safely
3290 * update _has_waiters flag.
3291 */
3292 if (cnt == 1) {
3293 umtxq_unlock(&key);
3294 error = suword32(&sem->_has_waiters, 0);
3295 umtxq_lock(&key);
3296 if (error == -1)
3297 error = EFAULT;
3298 }
3299 umtxq_signal(&key, 1);
3300 }
3301 umtxq_unbusy(&key);
3302 umtxq_unlock(&key);
3303 umtx_key_release(&key);
3304 return (error);
3305 }
3306 #endif
3307
3308 static int
do_sem2_wait(struct thread * td,struct _usem2 * sem,struct _umtx_time * timeout)3309 do_sem2_wait(struct thread *td, struct _usem2 *sem, struct _umtx_time *timeout)
3310 {
3311 struct abs_timeout timo;
3312 struct umtx_q *uq;
3313 uint32_t count, flags;
3314 int error, rv;
3315
3316 uq = td->td_umtxq;
3317 flags = fuword32(&sem->_flags);
3318 if (timeout != NULL)
3319 abs_timeout_init2(&timo, timeout);
3320
3321 again:
3322 error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &uq->uq_key);
3323 if (error != 0)
3324 return (error);
3325 umtxq_lock(&uq->uq_key);
3326 umtxq_busy(&uq->uq_key);
3327 umtxq_insert(uq);
3328 umtxq_unlock(&uq->uq_key);
3329 rv = fueword32(&sem->_count, &count);
3330 if (rv == -1) {
3331 umtxq_lock(&uq->uq_key);
3332 umtxq_unbusy(&uq->uq_key);
3333 umtxq_remove(uq);
3334 umtxq_unlock(&uq->uq_key);
3335 umtx_key_release(&uq->uq_key);
3336 return (EFAULT);
3337 }
3338 for (;;) {
3339 if (USEM_COUNT(count) != 0) {
3340 umtxq_lock(&uq->uq_key);
3341 umtxq_unbusy(&uq->uq_key);
3342 umtxq_remove(uq);
3343 umtxq_unlock(&uq->uq_key);
3344 umtx_key_release(&uq->uq_key);
3345 return (0);
3346 }
3347 if (count == USEM_HAS_WAITERS)
3348 break;
3349 rv = casueword32(&sem->_count, 0, &count, USEM_HAS_WAITERS);
3350 if (rv == 0)
3351 break;
3352 umtxq_lock(&uq->uq_key);
3353 umtxq_unbusy(&uq->uq_key);
3354 umtxq_remove(uq);
3355 umtxq_unlock(&uq->uq_key);
3356 umtx_key_release(&uq->uq_key);
3357 if (rv == -1)
3358 return (EFAULT);
3359 rv = umtxq_check_susp(td, true);
3360 if (rv != 0)
3361 return (rv);
3362 goto again;
3363 }
3364 umtxq_lock(&uq->uq_key);
3365 umtxq_unbusy(&uq->uq_key);
3366
3367 error = umtxq_sleep(uq, "usem", timeout == NULL ? NULL : &timo);
3368
3369 if ((uq->uq_flags & UQF_UMTXQ) == 0)
3370 error = 0;
3371 else {
3372 umtxq_remove(uq);
3373 if (timeout != NULL && (timeout->_flags & UMTX_ABSTIME) == 0) {
3374 /* A relative timeout cannot be restarted. */
3375 if (error == ERESTART)
3376 error = EINTR;
3377 if (error == EINTR) {
3378 abs_timeout_update(&timo);
3379 timespecsub(&timo.end, &timo.cur,
3380 &timeout->_timeout);
3381 }
3382 }
3383 }
3384 umtxq_unlock(&uq->uq_key);
3385 umtx_key_release(&uq->uq_key);
3386 return (error);
3387 }
3388
3389 /*
3390 * Signal a userland semaphore.
3391 */
3392 static int
do_sem2_wake(struct thread * td,struct _usem2 * sem)3393 do_sem2_wake(struct thread *td, struct _usem2 *sem)
3394 {
3395 struct umtx_key key;
3396 int error, cnt, rv;
3397 uint32_t count, flags;
3398
3399 rv = fueword32(&sem->_flags, &flags);
3400 if (rv == -1)
3401 return (EFAULT);
3402 if ((error = umtx_key_get(sem, TYPE_SEM, GET_SHARE(flags), &key)) != 0)
3403 return (error);
3404 umtxq_lock(&key);
3405 umtxq_busy(&key);
3406 cnt = umtxq_count(&key);
3407 if (cnt > 0) {
3408 /*
3409 * If this was the last sleeping thread, clear the waiters
3410 * flag in _count.
3411 */
3412 if (cnt == 1) {
3413 umtxq_unlock(&key);
3414 rv = fueword32(&sem->_count, &count);
3415 while (rv != -1 && count & USEM_HAS_WAITERS) {
3416 rv = casueword32(&sem->_count, count, &count,
3417 count & ~USEM_HAS_WAITERS);
3418 if (rv == 1) {
3419 rv = umtxq_check_susp(td, true);
3420 if (rv != 0)
3421 break;
3422 }
3423 }
3424 if (rv == -1)
3425 error = EFAULT;
3426 else if (rv > 0) {
3427 error = rv;
3428 }
3429 umtxq_lock(&key);
3430 }
3431
3432 umtxq_signal(&key, 1);
3433 }
3434 umtxq_unbusy(&key);
3435 umtxq_unlock(&key);
3436 umtx_key_release(&key);
3437 return (error);
3438 }
3439
3440 inline int
umtx_copyin_timeout(const void * addr,struct timespec * tsp)3441 umtx_copyin_timeout(const void *addr, struct timespec *tsp)
3442 {
3443 int error;
3444
3445 error = copyin(addr, tsp, sizeof(struct timespec));
3446 if (error == 0) {
3447 if (tsp->tv_sec < 0 ||
3448 tsp->tv_nsec >= 1000000000 ||
3449 tsp->tv_nsec < 0)
3450 error = EINVAL;
3451 }
3452 return (error);
3453 }
3454
3455 static inline int
umtx_copyin_umtx_time(const void * addr,size_t size,struct _umtx_time * tp)3456 umtx_copyin_umtx_time(const void *addr, size_t size, struct _umtx_time *tp)
3457 {
3458 int error;
3459
3460 if (size <= sizeof(struct timespec)) {
3461 tp->_clockid = CLOCK_REALTIME;
3462 tp->_flags = 0;
3463 error = copyin(addr, &tp->_timeout, sizeof(struct timespec));
3464 } else
3465 error = copyin(addr, tp, sizeof(struct _umtx_time));
3466 if (error != 0)
3467 return (error);
3468 if (tp->_timeout.tv_sec < 0 ||
3469 tp->_timeout.tv_nsec >= 1000000000 || tp->_timeout.tv_nsec < 0)
3470 return (EINVAL);
3471 return (0);
3472 }
3473
3474 static int
__umtx_op_unimpl(struct thread * td,struct _umtx_op_args * uap)3475 __umtx_op_unimpl(struct thread *td, struct _umtx_op_args *uap)
3476 {
3477
3478 return (EOPNOTSUPP);
3479 }
3480
3481 static int
__umtx_op_wait(struct thread * td,struct _umtx_op_args * uap)3482 __umtx_op_wait(struct thread *td, struct _umtx_op_args *uap)
3483 {
3484 struct _umtx_time timeout, *tm_p;
3485 int error;
3486
3487 if (uap->uaddr2 == NULL)
3488 tm_p = NULL;
3489 else {
3490 error = umtx_copyin_umtx_time(
3491 uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3492 if (error != 0)
3493 return (error);
3494 tm_p = &timeout;
3495 }
3496 return (do_wait(td, uap->obj, uap->val, tm_p, 0, 0));
3497 }
3498
3499 static int
__umtx_op_wait_uint(struct thread * td,struct _umtx_op_args * uap)3500 __umtx_op_wait_uint(struct thread *td, struct _umtx_op_args *uap)
3501 {
3502 struct _umtx_time timeout, *tm_p;
3503 int error;
3504
3505 if (uap->uaddr2 == NULL)
3506 tm_p = NULL;
3507 else {
3508 error = umtx_copyin_umtx_time(
3509 uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3510 if (error != 0)
3511 return (error);
3512 tm_p = &timeout;
3513 }
3514 return (do_wait(td, uap->obj, uap->val, tm_p, 1, 0));
3515 }
3516
3517 static int
__umtx_op_wait_uint_private(struct thread * td,struct _umtx_op_args * uap)3518 __umtx_op_wait_uint_private(struct thread *td, struct _umtx_op_args *uap)
3519 {
3520 struct _umtx_time *tm_p, timeout;
3521 int error;
3522
3523 if (uap->uaddr2 == NULL)
3524 tm_p = NULL;
3525 else {
3526 error = umtx_copyin_umtx_time(
3527 uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3528 if (error != 0)
3529 return (error);
3530 tm_p = &timeout;
3531 }
3532 return (do_wait(td, uap->obj, uap->val, tm_p, 1, 1));
3533 }
3534
3535 static int
__umtx_op_wake(struct thread * td,struct _umtx_op_args * uap)3536 __umtx_op_wake(struct thread *td, struct _umtx_op_args *uap)
3537 {
3538
3539 return (kern_umtx_wake(td, uap->obj, uap->val, 0));
3540 }
3541
3542 #define BATCH_SIZE 128
3543 static int
__umtx_op_nwake_private(struct thread * td,struct _umtx_op_args * uap)3544 __umtx_op_nwake_private(struct thread *td, struct _umtx_op_args *uap)
3545 {
3546 char *uaddrs[BATCH_SIZE], **upp;
3547 int count, error, i, pos, tocopy;
3548
3549 upp = (char **)uap->obj;
3550 error = 0;
3551 for (count = uap->val, pos = 0; count > 0; count -= tocopy,
3552 pos += tocopy) {
3553 tocopy = MIN(count, BATCH_SIZE);
3554 error = copyin(upp + pos, uaddrs, tocopy * sizeof(char *));
3555 if (error != 0)
3556 break;
3557 for (i = 0; i < tocopy; ++i)
3558 kern_umtx_wake(td, uaddrs[i], INT_MAX, 1);
3559 maybe_yield();
3560 }
3561 return (error);
3562 }
3563
3564 static int
__umtx_op_wake_private(struct thread * td,struct _umtx_op_args * uap)3565 __umtx_op_wake_private(struct thread *td, struct _umtx_op_args *uap)
3566 {
3567
3568 return (kern_umtx_wake(td, uap->obj, uap->val, 1));
3569 }
3570
3571 static int
__umtx_op_lock_umutex(struct thread * td,struct _umtx_op_args * uap)3572 __umtx_op_lock_umutex(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_lock_umutex(td, uap->obj, tm_p, 0));
3588 }
3589
3590 static int
__umtx_op_trylock_umutex(struct thread * td,struct _umtx_op_args * uap)3591 __umtx_op_trylock_umutex(struct thread *td, struct _umtx_op_args *uap)
3592 {
3593
3594 return (do_lock_umutex(td, uap->obj, NULL, _UMUTEX_TRY));
3595 }
3596
3597 static int
__umtx_op_wait_umutex(struct thread * td,struct _umtx_op_args * uap)3598 __umtx_op_wait_umutex(struct thread *td, struct _umtx_op_args *uap)
3599 {
3600 struct _umtx_time *tm_p, timeout;
3601 int error;
3602
3603 /* Allow a null timespec (wait forever). */
3604 if (uap->uaddr2 == NULL)
3605 tm_p = NULL;
3606 else {
3607 error = umtx_copyin_umtx_time(
3608 uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3609 if (error != 0)
3610 return (error);
3611 tm_p = &timeout;
3612 }
3613 return (do_lock_umutex(td, uap->obj, tm_p, _UMUTEX_WAIT));
3614 }
3615
3616 static int
__umtx_op_wake_umutex(struct thread * td,struct _umtx_op_args * uap)3617 __umtx_op_wake_umutex(struct thread *td, struct _umtx_op_args *uap)
3618 {
3619
3620 return (do_wake_umutex(td, uap->obj));
3621 }
3622
3623 static int
__umtx_op_unlock_umutex(struct thread * td,struct _umtx_op_args * uap)3624 __umtx_op_unlock_umutex(struct thread *td, struct _umtx_op_args *uap)
3625 {
3626
3627 return (do_unlock_umutex(td, uap->obj, false));
3628 }
3629
3630 static int
__umtx_op_set_ceiling(struct thread * td,struct _umtx_op_args * uap)3631 __umtx_op_set_ceiling(struct thread *td, struct _umtx_op_args *uap)
3632 {
3633
3634 return (do_set_ceiling(td, uap->obj, uap->val, uap->uaddr1));
3635 }
3636
3637 static int
__umtx_op_cv_wait(struct thread * td,struct _umtx_op_args * uap)3638 __umtx_op_cv_wait(struct thread *td, struct _umtx_op_args *uap)
3639 {
3640 struct timespec *ts, timeout;
3641 int error;
3642
3643 /* Allow a null timespec (wait forever). */
3644 if (uap->uaddr2 == NULL)
3645 ts = NULL;
3646 else {
3647 error = umtx_copyin_timeout(uap->uaddr2, &timeout);
3648 if (error != 0)
3649 return (error);
3650 ts = &timeout;
3651 }
3652 return (do_cv_wait(td, uap->obj, uap->uaddr1, ts, uap->val));
3653 }
3654
3655 static int
__umtx_op_cv_signal(struct thread * td,struct _umtx_op_args * uap)3656 __umtx_op_cv_signal(struct thread *td, struct _umtx_op_args *uap)
3657 {
3658
3659 return (do_cv_signal(td, uap->obj));
3660 }
3661
3662 static int
__umtx_op_cv_broadcast(struct thread * td,struct _umtx_op_args * uap)3663 __umtx_op_cv_broadcast(struct thread *td, struct _umtx_op_args *uap)
3664 {
3665
3666 return (do_cv_broadcast(td, uap->obj));
3667 }
3668
3669 static int
__umtx_op_rw_rdlock(struct thread * td,struct _umtx_op_args * uap)3670 __umtx_op_rw_rdlock(struct thread *td, struct _umtx_op_args *uap)
3671 {
3672 struct _umtx_time timeout;
3673 int error;
3674
3675 /* Allow a null timespec (wait forever). */
3676 if (uap->uaddr2 == NULL) {
3677 error = do_rw_rdlock(td, uap->obj, uap->val, 0);
3678 } else {
3679 error = umtx_copyin_umtx_time(uap->uaddr2,
3680 (size_t)uap->uaddr1, &timeout);
3681 if (error != 0)
3682 return (error);
3683 error = do_rw_rdlock(td, uap->obj, uap->val, &timeout);
3684 }
3685 return (error);
3686 }
3687
3688 static int
__umtx_op_rw_wrlock(struct thread * td,struct _umtx_op_args * uap)3689 __umtx_op_rw_wrlock(struct thread *td, struct _umtx_op_args *uap)
3690 {
3691 struct _umtx_time timeout;
3692 int error;
3693
3694 /* Allow a null timespec (wait forever). */
3695 if (uap->uaddr2 == NULL) {
3696 error = do_rw_wrlock(td, uap->obj, 0);
3697 } else {
3698 error = umtx_copyin_umtx_time(uap->uaddr2,
3699 (size_t)uap->uaddr1, &timeout);
3700 if (error != 0)
3701 return (error);
3702
3703 error = do_rw_wrlock(td, uap->obj, &timeout);
3704 }
3705 return (error);
3706 }
3707
3708 static int
__umtx_op_rw_unlock(struct thread * td,struct _umtx_op_args * uap)3709 __umtx_op_rw_unlock(struct thread *td, struct _umtx_op_args *uap)
3710 {
3711
3712 return (do_rw_unlock(td, uap->obj));
3713 }
3714
3715 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
3716 static int
__umtx_op_sem_wait(struct thread * td,struct _umtx_op_args * uap)3717 __umtx_op_sem_wait(struct thread *td, struct _umtx_op_args *uap)
3718 {
3719 struct _umtx_time *tm_p, timeout;
3720 int error;
3721
3722 /* Allow a null timespec (wait forever). */
3723 if (uap->uaddr2 == NULL)
3724 tm_p = NULL;
3725 else {
3726 error = umtx_copyin_umtx_time(
3727 uap->uaddr2, (size_t)uap->uaddr1, &timeout);
3728 if (error != 0)
3729 return (error);
3730 tm_p = &timeout;
3731 }
3732 return (do_sem_wait(td, uap->obj, tm_p));
3733 }
3734
3735 static int
__umtx_op_sem_wake(struct thread * td,struct _umtx_op_args * uap)3736 __umtx_op_sem_wake(struct thread *td, struct _umtx_op_args *uap)
3737 {
3738
3739 return (do_sem_wake(td, uap->obj));
3740 }
3741 #endif
3742
3743 static int
__umtx_op_wake2_umutex(struct thread * td,struct _umtx_op_args * uap)3744 __umtx_op_wake2_umutex(struct thread *td, struct _umtx_op_args *uap)
3745 {
3746
3747 return (do_wake2_umutex(td, uap->obj, uap->val));
3748 }
3749
3750 static int
__umtx_op_sem2_wait(struct thread * td,struct _umtx_op_args * uap)3751 __umtx_op_sem2_wait(struct thread *td, struct _umtx_op_args *uap)
3752 {
3753 struct _umtx_time *tm_p, timeout;
3754 size_t uasize;
3755 int error;
3756
3757 /* Allow a null timespec (wait forever). */
3758 if (uap->uaddr2 == NULL) {
3759 uasize = 0;
3760 tm_p = NULL;
3761 } else {
3762 uasize = (size_t)uap->uaddr1;
3763 error = umtx_copyin_umtx_time(uap->uaddr2, uasize, &timeout);
3764 if (error != 0)
3765 return (error);
3766 tm_p = &timeout;
3767 }
3768 error = do_sem2_wait(td, uap->obj, tm_p);
3769 if (error == EINTR && uap->uaddr2 != NULL &&
3770 (timeout._flags & UMTX_ABSTIME) == 0 &&
3771 uasize >= sizeof(struct _umtx_time) + sizeof(struct timespec)) {
3772 error = copyout(&timeout._timeout,
3773 (struct _umtx_time *)uap->uaddr2 + 1,
3774 sizeof(struct timespec));
3775 if (error == 0) {
3776 error = EINTR;
3777 }
3778 }
3779
3780 return (error);
3781 }
3782
3783 static int
__umtx_op_sem2_wake(struct thread * td,struct _umtx_op_args * uap)3784 __umtx_op_sem2_wake(struct thread *td, struct _umtx_op_args *uap)
3785 {
3786
3787 return (do_sem2_wake(td, uap->obj));
3788 }
3789
3790 #define USHM_OBJ_UMTX(o) \
3791 ((struct umtx_shm_obj_list *)(&(o)->umtx_data))
3792
3793 #define USHMF_REG_LINKED 0x0001
3794 #define USHMF_OBJ_LINKED 0x0002
3795 struct umtx_shm_reg {
3796 TAILQ_ENTRY(umtx_shm_reg) ushm_reg_link;
3797 LIST_ENTRY(umtx_shm_reg) ushm_obj_link;
3798 struct umtx_key ushm_key;
3799 struct ucred *ushm_cred;
3800 struct shmfd *ushm_obj;
3801 u_int ushm_refcnt;
3802 u_int ushm_flags;
3803 };
3804
3805 LIST_HEAD(umtx_shm_obj_list, umtx_shm_reg);
3806 TAILQ_HEAD(umtx_shm_reg_head, umtx_shm_reg);
3807
3808 static uma_zone_t umtx_shm_reg_zone;
3809 static struct umtx_shm_reg_head umtx_shm_registry[UMTX_CHAINS];
3810 static struct mtx umtx_shm_lock;
3811 static struct umtx_shm_reg_head umtx_shm_reg_delfree =
3812 TAILQ_HEAD_INITIALIZER(umtx_shm_reg_delfree);
3813
3814 static void umtx_shm_free_reg(struct umtx_shm_reg *reg);
3815
3816 static void
umtx_shm_reg_delfree_tq(void * context __unused,int pending __unused)3817 umtx_shm_reg_delfree_tq(void *context __unused, int pending __unused)
3818 {
3819 struct umtx_shm_reg_head d;
3820 struct umtx_shm_reg *reg, *reg1;
3821
3822 TAILQ_INIT(&d);
3823 mtx_lock(&umtx_shm_lock);
3824 TAILQ_CONCAT(&d, &umtx_shm_reg_delfree, ushm_reg_link);
3825 mtx_unlock(&umtx_shm_lock);
3826 TAILQ_FOREACH_SAFE(reg, &d, ushm_reg_link, reg1) {
3827 TAILQ_REMOVE(&d, reg, ushm_reg_link);
3828 umtx_shm_free_reg(reg);
3829 }
3830 }
3831
3832 static struct task umtx_shm_reg_delfree_task =
3833 TASK_INITIALIZER(0, umtx_shm_reg_delfree_tq, NULL);
3834
3835 static struct umtx_shm_reg *
umtx_shm_find_reg_locked(const struct umtx_key * key)3836 umtx_shm_find_reg_locked(const struct umtx_key *key)
3837 {
3838 struct umtx_shm_reg *reg;
3839 struct umtx_shm_reg_head *reg_head;
3840
3841 KASSERT(key->shared, ("umtx_p_find_rg: private key"));
3842 mtx_assert(&umtx_shm_lock, MA_OWNED);
3843 reg_head = &umtx_shm_registry[key->hash];
3844 TAILQ_FOREACH(reg, reg_head, ushm_reg_link) {
3845 KASSERT(reg->ushm_key.shared,
3846 ("non-shared key on reg %p %d", reg, reg->ushm_key.shared));
3847 if (reg->ushm_key.info.shared.object ==
3848 key->info.shared.object &&
3849 reg->ushm_key.info.shared.offset ==
3850 key->info.shared.offset) {
3851 KASSERT(reg->ushm_key.type == TYPE_SHM, ("TYPE_USHM"));
3852 KASSERT(reg->ushm_refcnt > 0,
3853 ("reg %p refcnt 0 onlist", reg));
3854 KASSERT((reg->ushm_flags & USHMF_REG_LINKED) != 0,
3855 ("reg %p not linked", reg));
3856 reg->ushm_refcnt++;
3857 return (reg);
3858 }
3859 }
3860 return (NULL);
3861 }
3862
3863 static struct umtx_shm_reg *
umtx_shm_find_reg(const struct umtx_key * key)3864 umtx_shm_find_reg(const struct umtx_key *key)
3865 {
3866 struct umtx_shm_reg *reg;
3867
3868 mtx_lock(&umtx_shm_lock);
3869 reg = umtx_shm_find_reg_locked(key);
3870 mtx_unlock(&umtx_shm_lock);
3871 return (reg);
3872 }
3873
3874 static void
umtx_shm_free_reg(struct umtx_shm_reg * reg)3875 umtx_shm_free_reg(struct umtx_shm_reg *reg)
3876 {
3877
3878 chgumtxcnt(reg->ushm_cred->cr_ruidinfo, -1, 0);
3879 crfree(reg->ushm_cred);
3880 shm_drop(reg->ushm_obj);
3881 uma_zfree(umtx_shm_reg_zone, reg);
3882 }
3883
3884 static bool
umtx_shm_unref_reg_locked(struct umtx_shm_reg * reg,bool force)3885 umtx_shm_unref_reg_locked(struct umtx_shm_reg *reg, bool force)
3886 {
3887 bool res;
3888
3889 mtx_assert(&umtx_shm_lock, MA_OWNED);
3890 KASSERT(reg->ushm_refcnt > 0, ("ushm_reg %p refcnt 0", reg));
3891 reg->ushm_refcnt--;
3892 res = reg->ushm_refcnt == 0;
3893 if (res || force) {
3894 if ((reg->ushm_flags & USHMF_REG_LINKED) != 0) {
3895 TAILQ_REMOVE(&umtx_shm_registry[reg->ushm_key.hash],
3896 reg, ushm_reg_link);
3897 reg->ushm_flags &= ~USHMF_REG_LINKED;
3898 }
3899 if ((reg->ushm_flags & USHMF_OBJ_LINKED) != 0) {
3900 LIST_REMOVE(reg, ushm_obj_link);
3901 reg->ushm_flags &= ~USHMF_OBJ_LINKED;
3902 }
3903 }
3904 return (res);
3905 }
3906
3907 static void
umtx_shm_unref_reg(struct umtx_shm_reg * reg,bool force)3908 umtx_shm_unref_reg(struct umtx_shm_reg *reg, bool force)
3909 {
3910 vm_object_t object;
3911 bool dofree;
3912
3913 if (force) {
3914 object = reg->ushm_obj->shm_object;
3915 VM_OBJECT_WLOCK(object);
3916 object->flags |= OBJ_UMTXDEAD;
3917 VM_OBJECT_WUNLOCK(object);
3918 }
3919 mtx_lock(&umtx_shm_lock);
3920 dofree = umtx_shm_unref_reg_locked(reg, force);
3921 mtx_unlock(&umtx_shm_lock);
3922 if (dofree)
3923 umtx_shm_free_reg(reg);
3924 }
3925
3926 void
umtx_shm_object_init(vm_object_t object)3927 umtx_shm_object_init(vm_object_t object)
3928 {
3929
3930 LIST_INIT(USHM_OBJ_UMTX(object));
3931 }
3932
3933 void
umtx_shm_object_terminated(vm_object_t object)3934 umtx_shm_object_terminated(vm_object_t object)
3935 {
3936 struct umtx_shm_reg *reg, *reg1;
3937 bool dofree;
3938
3939 dofree = false;
3940 mtx_lock(&umtx_shm_lock);
3941 LIST_FOREACH_SAFE(reg, USHM_OBJ_UMTX(object), ushm_obj_link, reg1) {
3942 if (umtx_shm_unref_reg_locked(reg, true)) {
3943 TAILQ_INSERT_TAIL(&umtx_shm_reg_delfree, reg,
3944 ushm_reg_link);
3945 dofree = true;
3946 }
3947 }
3948 mtx_unlock(&umtx_shm_lock);
3949 if (dofree)
3950 taskqueue_enqueue(taskqueue_thread, &umtx_shm_reg_delfree_task);
3951 }
3952
3953 static int
umtx_shm_create_reg(struct thread * td,const struct umtx_key * key,struct umtx_shm_reg ** res)3954 umtx_shm_create_reg(struct thread *td, const struct umtx_key *key,
3955 struct umtx_shm_reg **res)
3956 {
3957 struct umtx_shm_reg *reg, *reg1;
3958 struct ucred *cred;
3959 int error;
3960
3961 reg = umtx_shm_find_reg(key);
3962 if (reg != NULL) {
3963 *res = reg;
3964 return (0);
3965 }
3966 cred = td->td_ucred;
3967 if (!chgumtxcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_UMTXP)))
3968 return (ENOMEM);
3969 reg = uma_zalloc(umtx_shm_reg_zone, M_WAITOK | M_ZERO);
3970 reg->ushm_refcnt = 1;
3971 bcopy(key, ®->ushm_key, sizeof(*key));
3972 reg->ushm_obj = shm_alloc(td->td_ucred, O_RDWR);
3973 reg->ushm_cred = crhold(cred);
3974 error = shm_dotruncate(reg->ushm_obj, PAGE_SIZE);
3975 if (error != 0) {
3976 umtx_shm_free_reg(reg);
3977 return (error);
3978 }
3979 mtx_lock(&umtx_shm_lock);
3980 reg1 = umtx_shm_find_reg_locked(key);
3981 if (reg1 != NULL) {
3982 mtx_unlock(&umtx_shm_lock);
3983 umtx_shm_free_reg(reg);
3984 *res = reg1;
3985 return (0);
3986 }
3987 reg->ushm_refcnt++;
3988 TAILQ_INSERT_TAIL(&umtx_shm_registry[key->hash], reg, ushm_reg_link);
3989 LIST_INSERT_HEAD(USHM_OBJ_UMTX(key->info.shared.object), reg,
3990 ushm_obj_link);
3991 reg->ushm_flags = USHMF_REG_LINKED | USHMF_OBJ_LINKED;
3992 mtx_unlock(&umtx_shm_lock);
3993 *res = reg;
3994 return (0);
3995 }
3996
3997 static int
umtx_shm_alive(struct thread * td,void * addr)3998 umtx_shm_alive(struct thread *td, void *addr)
3999 {
4000 vm_map_t map;
4001 vm_map_entry_t entry;
4002 vm_object_t object;
4003 vm_pindex_t pindex;
4004 vm_prot_t prot;
4005 int res, ret;
4006 boolean_t wired;
4007
4008 map = &td->td_proc->p_vmspace->vm_map;
4009 res = vm_map_lookup(&map, (uintptr_t)addr, VM_PROT_READ, &entry,
4010 &object, &pindex, &prot, &wired);
4011 if (res != KERN_SUCCESS)
4012 return (EFAULT);
4013 if (object == NULL)
4014 ret = EINVAL;
4015 else
4016 ret = (object->flags & OBJ_UMTXDEAD) != 0 ? ENOTTY : 0;
4017 vm_map_lookup_done(map, entry);
4018 return (ret);
4019 }
4020
4021 static void
umtx_shm_init(void)4022 umtx_shm_init(void)
4023 {
4024 int i;
4025
4026 umtx_shm_reg_zone = uma_zcreate("umtx_shm", sizeof(struct umtx_shm_reg),
4027 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
4028 mtx_init(&umtx_shm_lock, "umtxshm", NULL, MTX_DEF);
4029 for (i = 0; i < nitems(umtx_shm_registry); i++)
4030 TAILQ_INIT(&umtx_shm_registry[i]);
4031 }
4032
4033 static int
umtx_shm(struct thread * td,void * addr,u_int flags)4034 umtx_shm(struct thread *td, void *addr, u_int flags)
4035 {
4036 struct umtx_key key;
4037 struct umtx_shm_reg *reg;
4038 struct file *fp;
4039 int error, fd;
4040
4041 if (__bitcount(flags & (UMTX_SHM_CREAT | UMTX_SHM_LOOKUP |
4042 UMTX_SHM_DESTROY| UMTX_SHM_ALIVE)) != 1)
4043 return (EINVAL);
4044 if ((flags & UMTX_SHM_ALIVE) != 0)
4045 return (umtx_shm_alive(td, addr));
4046 error = umtx_key_get(addr, TYPE_SHM, PROCESS_SHARE, &key);
4047 if (error != 0)
4048 return (error);
4049 KASSERT(key.shared == 1, ("non-shared key"));
4050 if ((flags & UMTX_SHM_CREAT) != 0) {
4051 error = umtx_shm_create_reg(td, &key, ®);
4052 } else {
4053 reg = umtx_shm_find_reg(&key);
4054 if (reg == NULL)
4055 error = ESRCH;
4056 }
4057 umtx_key_release(&key);
4058 if (error != 0)
4059 return (error);
4060 KASSERT(reg != NULL, ("no reg"));
4061 if ((flags & UMTX_SHM_DESTROY) != 0) {
4062 umtx_shm_unref_reg(reg, true);
4063 } else {
4064 #if 0
4065 #ifdef MAC
4066 error = mac_posixshm_check_open(td->td_ucred,
4067 reg->ushm_obj, FFLAGS(O_RDWR));
4068 if (error == 0)
4069 #endif
4070 error = shm_access(reg->ushm_obj, td->td_ucred,
4071 FFLAGS(O_RDWR));
4072 if (error == 0)
4073 #endif
4074 error = falloc_caps(td, &fp, &fd, O_CLOEXEC, NULL);
4075 if (error == 0) {
4076 shm_hold(reg->ushm_obj);
4077 finit(fp, FFLAGS(O_RDWR), DTYPE_SHM, reg->ushm_obj,
4078 &shm_ops);
4079 td->td_retval[0] = fd;
4080 fdrop(fp, td);
4081 }
4082 }
4083 umtx_shm_unref_reg(reg, false);
4084 return (error);
4085 }
4086
4087 static int
__umtx_op_shm(struct thread * td,struct _umtx_op_args * uap)4088 __umtx_op_shm(struct thread *td, struct _umtx_op_args *uap)
4089 {
4090
4091 return (umtx_shm(td, uap->uaddr1, uap->val));
4092 }
4093
4094 static int
umtx_robust_lists(struct thread * td,struct umtx_robust_lists_params * rbp)4095 umtx_robust_lists(struct thread *td, struct umtx_robust_lists_params *rbp)
4096 {
4097
4098 td->td_rb_list = rbp->robust_list_offset;
4099 td->td_rbp_list = rbp->robust_priv_list_offset;
4100 td->td_rb_inact = rbp->robust_inact_offset;
4101 return (0);
4102 }
4103
4104 static int
__umtx_op_robust_lists(struct thread * td,struct _umtx_op_args * uap)4105 __umtx_op_robust_lists(struct thread *td, struct _umtx_op_args *uap)
4106 {
4107 struct umtx_robust_lists_params rb;
4108 int error;
4109
4110 if (uap->val > sizeof(rb))
4111 return (EINVAL);
4112 bzero(&rb, sizeof(rb));
4113 error = copyin(uap->uaddr1, &rb, uap->val);
4114 if (error != 0)
4115 return (error);
4116 return (umtx_robust_lists(td, &rb));
4117 }
4118
4119 typedef int (*_umtx_op_func)(struct thread *td, struct _umtx_op_args *uap);
4120
4121 static const _umtx_op_func op_table[] = {
4122 [UMTX_OP_RESERVED0] = __umtx_op_unimpl,
4123 [UMTX_OP_RESERVED1] = __umtx_op_unimpl,
4124 [UMTX_OP_WAIT] = __umtx_op_wait,
4125 [UMTX_OP_WAKE] = __umtx_op_wake,
4126 [UMTX_OP_MUTEX_TRYLOCK] = __umtx_op_trylock_umutex,
4127 [UMTX_OP_MUTEX_LOCK] = __umtx_op_lock_umutex,
4128 [UMTX_OP_MUTEX_UNLOCK] = __umtx_op_unlock_umutex,
4129 [UMTX_OP_SET_CEILING] = __umtx_op_set_ceiling,
4130 [UMTX_OP_CV_WAIT] = __umtx_op_cv_wait,
4131 [UMTX_OP_CV_SIGNAL] = __umtx_op_cv_signal,
4132 [UMTX_OP_CV_BROADCAST] = __umtx_op_cv_broadcast,
4133 [UMTX_OP_WAIT_UINT] = __umtx_op_wait_uint,
4134 [UMTX_OP_RW_RDLOCK] = __umtx_op_rw_rdlock,
4135 [UMTX_OP_RW_WRLOCK] = __umtx_op_rw_wrlock,
4136 [UMTX_OP_RW_UNLOCK] = __umtx_op_rw_unlock,
4137 [UMTX_OP_WAIT_UINT_PRIVATE] = __umtx_op_wait_uint_private,
4138 [UMTX_OP_WAKE_PRIVATE] = __umtx_op_wake_private,
4139 [UMTX_OP_MUTEX_WAIT] = __umtx_op_wait_umutex,
4140 [UMTX_OP_MUTEX_WAKE] = __umtx_op_wake_umutex,
4141 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
4142 [UMTX_OP_SEM_WAIT] = __umtx_op_sem_wait,
4143 [UMTX_OP_SEM_WAKE] = __umtx_op_sem_wake,
4144 #else
4145 [UMTX_OP_SEM_WAIT] = __umtx_op_unimpl,
4146 [UMTX_OP_SEM_WAKE] = __umtx_op_unimpl,
4147 #endif
4148 [UMTX_OP_NWAKE_PRIVATE] = __umtx_op_nwake_private,
4149 [UMTX_OP_MUTEX_WAKE2] = __umtx_op_wake2_umutex,
4150 [UMTX_OP_SEM2_WAIT] = __umtx_op_sem2_wait,
4151 [UMTX_OP_SEM2_WAKE] = __umtx_op_sem2_wake,
4152 [UMTX_OP_SHM] = __umtx_op_shm,
4153 [UMTX_OP_ROBUST_LISTS] = __umtx_op_robust_lists,
4154 };
4155
4156 int
sys__umtx_op(struct thread * td,struct _umtx_op_args * uap)4157 sys__umtx_op(struct thread *td, struct _umtx_op_args *uap)
4158 {
4159
4160 if ((unsigned)uap->op < nitems(op_table))
4161 return (*op_table[uap->op])(td, uap);
4162 return (EINVAL);
4163 }
4164
4165 #ifdef COMPAT_FREEBSD32
4166
4167 struct timespec32 {
4168 int32_t tv_sec;
4169 int32_t tv_nsec;
4170 };
4171
4172 struct umtx_time32 {
4173 struct timespec32 timeout;
4174 uint32_t flags;
4175 uint32_t clockid;
4176 };
4177
4178 static inline int
umtx_copyin_timeout32(void * addr,struct timespec * tsp)4179 umtx_copyin_timeout32(void *addr, struct timespec *tsp)
4180 {
4181 struct timespec32 ts32;
4182 int error;
4183
4184 error = copyin(addr, &ts32, sizeof(struct timespec32));
4185 if (error == 0) {
4186 if (ts32.tv_sec < 0 ||
4187 ts32.tv_nsec >= 1000000000 ||
4188 ts32.tv_nsec < 0)
4189 error = EINVAL;
4190 else {
4191 tsp->tv_sec = ts32.tv_sec;
4192 tsp->tv_nsec = ts32.tv_nsec;
4193 }
4194 }
4195 return (error);
4196 }
4197
4198 static inline int
umtx_copyin_umtx_time32(const void * addr,size_t size,struct _umtx_time * tp)4199 umtx_copyin_umtx_time32(const void *addr, size_t size, struct _umtx_time *tp)
4200 {
4201 struct umtx_time32 t32;
4202 int error;
4203
4204 t32.clockid = CLOCK_REALTIME;
4205 t32.flags = 0;
4206 if (size <= sizeof(struct timespec32))
4207 error = copyin(addr, &t32.timeout, sizeof(struct timespec32));
4208 else
4209 error = copyin(addr, &t32, sizeof(struct umtx_time32));
4210 if (error != 0)
4211 return (error);
4212 if (t32.timeout.tv_sec < 0 ||
4213 t32.timeout.tv_nsec >= 1000000000 || t32.timeout.tv_nsec < 0)
4214 return (EINVAL);
4215 tp->_timeout.tv_sec = t32.timeout.tv_sec;
4216 tp->_timeout.tv_nsec = t32.timeout.tv_nsec;
4217 tp->_flags = t32.flags;
4218 tp->_clockid = t32.clockid;
4219 return (0);
4220 }
4221
4222 static int
__umtx_op_wait_compat32(struct thread * td,struct _umtx_op_args * uap)4223 __umtx_op_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
4224 {
4225 struct _umtx_time *tm_p, timeout;
4226 int error;
4227
4228 if (uap->uaddr2 == NULL)
4229 tm_p = NULL;
4230 else {
4231 error = umtx_copyin_umtx_time32(uap->uaddr2,
4232 (size_t)uap->uaddr1, &timeout);
4233 if (error != 0)
4234 return (error);
4235 tm_p = &timeout;
4236 }
4237 return (do_wait(td, uap->obj, uap->val, tm_p, 1, 0));
4238 }
4239
4240 static int
__umtx_op_lock_umutex_compat32(struct thread * td,struct _umtx_op_args * uap)4241 __umtx_op_lock_umutex_compat32(struct thread *td, struct _umtx_op_args *uap)
4242 {
4243 struct _umtx_time *tm_p, timeout;
4244 int error;
4245
4246 /* Allow a null timespec (wait forever). */
4247 if (uap->uaddr2 == NULL)
4248 tm_p = NULL;
4249 else {
4250 error = umtx_copyin_umtx_time32(uap->uaddr2,
4251 (size_t)uap->uaddr1, &timeout);
4252 if (error != 0)
4253 return (error);
4254 tm_p = &timeout;
4255 }
4256 return (do_lock_umutex(td, uap->obj, tm_p, 0));
4257 }
4258
4259 static int
__umtx_op_wait_umutex_compat32(struct thread * td,struct _umtx_op_args * uap)4260 __umtx_op_wait_umutex_compat32(struct thread *td, struct _umtx_op_args *uap)
4261 {
4262 struct _umtx_time *tm_p, timeout;
4263 int error;
4264
4265 /* Allow a null timespec (wait forever). */
4266 if (uap->uaddr2 == NULL)
4267 tm_p = NULL;
4268 else {
4269 error = umtx_copyin_umtx_time32(uap->uaddr2,
4270 (size_t)uap->uaddr1, &timeout);
4271 if (error != 0)
4272 return (error);
4273 tm_p = &timeout;
4274 }
4275 return (do_lock_umutex(td, uap->obj, tm_p, _UMUTEX_WAIT));
4276 }
4277
4278 static int
__umtx_op_cv_wait_compat32(struct thread * td,struct _umtx_op_args * uap)4279 __umtx_op_cv_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
4280 {
4281 struct timespec *ts, timeout;
4282 int error;
4283
4284 /* Allow a null timespec (wait forever). */
4285 if (uap->uaddr2 == NULL)
4286 ts = NULL;
4287 else {
4288 error = umtx_copyin_timeout32(uap->uaddr2, &timeout);
4289 if (error != 0)
4290 return (error);
4291 ts = &timeout;
4292 }
4293 return (do_cv_wait(td, uap->obj, uap->uaddr1, ts, uap->val));
4294 }
4295
4296 static int
__umtx_op_rw_rdlock_compat32(struct thread * td,struct _umtx_op_args * uap)4297 __umtx_op_rw_rdlock_compat32(struct thread *td, struct _umtx_op_args *uap)
4298 {
4299 struct _umtx_time timeout;
4300 int error;
4301
4302 /* Allow a null timespec (wait forever). */
4303 if (uap->uaddr2 == NULL) {
4304 error = do_rw_rdlock(td, uap->obj, uap->val, 0);
4305 } else {
4306 error = umtx_copyin_umtx_time32(uap->uaddr2,
4307 (size_t)uap->uaddr1, &timeout);
4308 if (error != 0)
4309 return (error);
4310 error = do_rw_rdlock(td, uap->obj, uap->val, &timeout);
4311 }
4312 return (error);
4313 }
4314
4315 static int
__umtx_op_rw_wrlock_compat32(struct thread * td,struct _umtx_op_args * uap)4316 __umtx_op_rw_wrlock_compat32(struct thread *td, struct _umtx_op_args *uap)
4317 {
4318 struct _umtx_time timeout;
4319 int error;
4320
4321 /* Allow a null timespec (wait forever). */
4322 if (uap->uaddr2 == NULL) {
4323 error = do_rw_wrlock(td, uap->obj, 0);
4324 } else {
4325 error = umtx_copyin_umtx_time32(uap->uaddr2,
4326 (size_t)uap->uaddr1, &timeout);
4327 if (error != 0)
4328 return (error);
4329 error = do_rw_wrlock(td, uap->obj, &timeout);
4330 }
4331 return (error);
4332 }
4333
4334 static int
__umtx_op_wait_uint_private_compat32(struct thread * td,struct _umtx_op_args * uap)4335 __umtx_op_wait_uint_private_compat32(struct thread *td, struct _umtx_op_args *uap)
4336 {
4337 struct _umtx_time *tm_p, timeout;
4338 int error;
4339
4340 if (uap->uaddr2 == NULL)
4341 tm_p = NULL;
4342 else {
4343 error = umtx_copyin_umtx_time32(
4344 uap->uaddr2, (size_t)uap->uaddr1,&timeout);
4345 if (error != 0)
4346 return (error);
4347 tm_p = &timeout;
4348 }
4349 return (do_wait(td, uap->obj, uap->val, tm_p, 1, 1));
4350 }
4351
4352 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
4353 static int
__umtx_op_sem_wait_compat32(struct thread * td,struct _umtx_op_args * uap)4354 __umtx_op_sem_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
4355 {
4356 struct _umtx_time *tm_p, timeout;
4357 int error;
4358
4359 /* Allow a null timespec (wait forever). */
4360 if (uap->uaddr2 == NULL)
4361 tm_p = NULL;
4362 else {
4363 error = umtx_copyin_umtx_time32(uap->uaddr2,
4364 (size_t)uap->uaddr1, &timeout);
4365 if (error != 0)
4366 return (error);
4367 tm_p = &timeout;
4368 }
4369 return (do_sem_wait(td, uap->obj, tm_p));
4370 }
4371 #endif
4372
4373 static int
__umtx_op_sem2_wait_compat32(struct thread * td,struct _umtx_op_args * uap)4374 __umtx_op_sem2_wait_compat32(struct thread *td, struct _umtx_op_args *uap)
4375 {
4376 struct _umtx_time *tm_p, timeout;
4377 size_t uasize;
4378 int error;
4379
4380 /* Allow a null timespec (wait forever). */
4381 if (uap->uaddr2 == NULL) {
4382 uasize = 0;
4383 tm_p = NULL;
4384 } else {
4385 uasize = (size_t)uap->uaddr1;
4386 error = umtx_copyin_umtx_time32(uap->uaddr2, uasize, &timeout);
4387 if (error != 0)
4388 return (error);
4389 tm_p = &timeout;
4390 }
4391 error = do_sem2_wait(td, uap->obj, tm_p);
4392 if (error == EINTR && uap->uaddr2 != NULL &&
4393 (timeout._flags & UMTX_ABSTIME) == 0 &&
4394 uasize >= sizeof(struct umtx_time32) + sizeof(struct timespec32)) {
4395 struct timespec32 remain32 = {
4396 .tv_sec = timeout._timeout.tv_sec,
4397 .tv_nsec = timeout._timeout.tv_nsec
4398 };
4399 error = copyout(&remain32,
4400 (struct umtx_time32 *)uap->uaddr2 + 1,
4401 sizeof(struct timespec32));
4402 if (error == 0) {
4403 error = EINTR;
4404 }
4405 }
4406
4407 return (error);
4408 }
4409
4410 static int
__umtx_op_nwake_private32(struct thread * td,struct _umtx_op_args * uap)4411 __umtx_op_nwake_private32(struct thread *td, struct _umtx_op_args *uap)
4412 {
4413 uint32_t uaddrs[BATCH_SIZE], **upp;
4414 int count, error, i, pos, tocopy;
4415
4416 upp = (uint32_t **)uap->obj;
4417 error = 0;
4418 for (count = uap->val, pos = 0; count > 0; count -= tocopy,
4419 pos += tocopy) {
4420 tocopy = MIN(count, BATCH_SIZE);
4421 error = copyin(upp + pos, uaddrs, tocopy * sizeof(uint32_t));
4422 if (error != 0)
4423 break;
4424 for (i = 0; i < tocopy; ++i)
4425 kern_umtx_wake(td, (void *)(intptr_t)uaddrs[i],
4426 INT_MAX, 1);
4427 maybe_yield();
4428 }
4429 return (error);
4430 }
4431
4432 struct umtx_robust_lists_params_compat32 {
4433 uint32_t robust_list_offset;
4434 uint32_t robust_priv_list_offset;
4435 uint32_t robust_inact_offset;
4436 };
4437
4438 static int
__umtx_op_robust_lists_compat32(struct thread * td,struct _umtx_op_args * uap)4439 __umtx_op_robust_lists_compat32(struct thread *td, struct _umtx_op_args *uap)
4440 {
4441 struct umtx_robust_lists_params rb;
4442 struct umtx_robust_lists_params_compat32 rb32;
4443 int error;
4444
4445 if (uap->val > sizeof(rb32))
4446 return (EINVAL);
4447 bzero(&rb, sizeof(rb));
4448 bzero(&rb32, sizeof(rb32));
4449 error = copyin(uap->uaddr1, &rb32, uap->val);
4450 if (error != 0)
4451 return (error);
4452 rb.robust_list_offset = rb32.robust_list_offset;
4453 rb.robust_priv_list_offset = rb32.robust_priv_list_offset;
4454 rb.robust_inact_offset = rb32.robust_inact_offset;
4455 return (umtx_robust_lists(td, &rb));
4456 }
4457
4458 static const _umtx_op_func op_table_compat32[] = {
4459 [UMTX_OP_RESERVED0] = __umtx_op_unimpl,
4460 [UMTX_OP_RESERVED1] = __umtx_op_unimpl,
4461 [UMTX_OP_WAIT] = __umtx_op_wait_compat32,
4462 [UMTX_OP_WAKE] = __umtx_op_wake,
4463 [UMTX_OP_MUTEX_TRYLOCK] = __umtx_op_trylock_umutex,
4464 [UMTX_OP_MUTEX_LOCK] = __umtx_op_lock_umutex_compat32,
4465 [UMTX_OP_MUTEX_UNLOCK] = __umtx_op_unlock_umutex,
4466 [UMTX_OP_SET_CEILING] = __umtx_op_set_ceiling,
4467 [UMTX_OP_CV_WAIT] = __umtx_op_cv_wait_compat32,
4468 [UMTX_OP_CV_SIGNAL] = __umtx_op_cv_signal,
4469 [UMTX_OP_CV_BROADCAST] = __umtx_op_cv_broadcast,
4470 [UMTX_OP_WAIT_UINT] = __umtx_op_wait_compat32,
4471 [UMTX_OP_RW_RDLOCK] = __umtx_op_rw_rdlock_compat32,
4472 [UMTX_OP_RW_WRLOCK] = __umtx_op_rw_wrlock_compat32,
4473 [UMTX_OP_RW_UNLOCK] = __umtx_op_rw_unlock,
4474 [UMTX_OP_WAIT_UINT_PRIVATE] = __umtx_op_wait_uint_private_compat32,
4475 [UMTX_OP_WAKE_PRIVATE] = __umtx_op_wake_private,
4476 [UMTX_OP_MUTEX_WAIT] = __umtx_op_wait_umutex_compat32,
4477 [UMTX_OP_MUTEX_WAKE] = __umtx_op_wake_umutex,
4478 #if defined(COMPAT_FREEBSD9) || defined(COMPAT_FREEBSD10)
4479 [UMTX_OP_SEM_WAIT] = __umtx_op_sem_wait_compat32,
4480 [UMTX_OP_SEM_WAKE] = __umtx_op_sem_wake,
4481 #else
4482 [UMTX_OP_SEM_WAIT] = __umtx_op_unimpl,
4483 [UMTX_OP_SEM_WAKE] = __umtx_op_unimpl,
4484 #endif
4485 [UMTX_OP_NWAKE_PRIVATE] = __umtx_op_nwake_private32,
4486 [UMTX_OP_MUTEX_WAKE2] = __umtx_op_wake2_umutex,
4487 [UMTX_OP_SEM2_WAIT] = __umtx_op_sem2_wait_compat32,
4488 [UMTX_OP_SEM2_WAKE] = __umtx_op_sem2_wake,
4489 [UMTX_OP_SHM] = __umtx_op_shm,
4490 [UMTX_OP_ROBUST_LISTS] = __umtx_op_robust_lists_compat32,
4491 };
4492
4493 int
freebsd32__umtx_op(struct thread * td,struct freebsd32__umtx_op_args * uap)4494 freebsd32__umtx_op(struct thread *td, struct freebsd32__umtx_op_args *uap)
4495 {
4496
4497 if ((unsigned)uap->op < nitems(op_table_compat32)) {
4498 return (*op_table_compat32[uap->op])(td,
4499 (struct _umtx_op_args *)uap);
4500 }
4501 return (EINVAL);
4502 }
4503 #endif
4504
4505 void
umtx_thread_init(struct thread * td)4506 umtx_thread_init(struct thread *td)
4507 {
4508
4509 td->td_umtxq = umtxq_alloc();
4510 td->td_umtxq->uq_thread = td;
4511 }
4512
4513 void
umtx_thread_fini(struct thread * td)4514 umtx_thread_fini(struct thread *td)
4515 {
4516
4517 umtxq_free(td->td_umtxq);
4518 }
4519
4520 /*
4521 * It will be called when new thread is created, e.g fork().
4522 */
4523 void
umtx_thread_alloc(struct thread * td)4524 umtx_thread_alloc(struct thread *td)
4525 {
4526 struct umtx_q *uq;
4527
4528 uq = td->td_umtxq;
4529 uq->uq_inherited_pri = PRI_MAX;
4530
4531 KASSERT(uq->uq_flags == 0, ("uq_flags != 0"));
4532 KASSERT(uq->uq_thread == td, ("uq_thread != td"));
4533 KASSERT(uq->uq_pi_blocked == NULL, ("uq_pi_blocked != NULL"));
4534 KASSERT(TAILQ_EMPTY(&uq->uq_pi_contested), ("uq_pi_contested is not empty"));
4535 }
4536
4537 /*
4538 * exec() hook.
4539 *
4540 * Clear robust lists for all process' threads, not delaying the
4541 * cleanup to thread_exit hook, since the relevant address space is
4542 * destroyed right now.
4543 */
4544 static void
umtx_exec_hook(void * arg __unused,struct proc * p,struct image_params * imgp __unused)4545 umtx_exec_hook(void *arg __unused, struct proc *p,
4546 struct image_params *imgp __unused)
4547 {
4548 struct thread *td;
4549
4550 KASSERT(p == curproc, ("need curproc"));
4551 PROC_LOCK(p);
4552 KASSERT((p->p_flag & P_HADTHREADS) == 0 ||
4553 (p->p_flag & P_STOPPED_SINGLE) != 0,
4554 ("curproc must be single-threaded"));
4555 FOREACH_THREAD_IN_PROC(p, td) {
4556 KASSERT(td == curthread ||
4557 ((td->td_flags & TDF_BOUNDARY) != 0 && TD_IS_SUSPENDED(td)),
4558 ("running thread %p %p", p, td));
4559 PROC_UNLOCK(p);
4560 umtx_thread_cleanup(td);
4561 PROC_LOCK(p);
4562 td->td_rb_list = td->td_rbp_list = td->td_rb_inact = 0;
4563 }
4564 PROC_UNLOCK(p);
4565 }
4566
4567 /*
4568 * thread_exit() hook.
4569 */
4570 void
umtx_thread_exit(struct thread * td)4571 umtx_thread_exit(struct thread *td)
4572 {
4573
4574 umtx_thread_cleanup(td);
4575 }
4576
4577 static int
umtx_read_uptr(struct thread * td,uintptr_t ptr,uintptr_t * res)4578 umtx_read_uptr(struct thread *td, uintptr_t ptr, uintptr_t *res)
4579 {
4580 u_long res1;
4581 #ifdef COMPAT_FREEBSD32
4582 uint32_t res32;
4583 #endif
4584 int error;
4585
4586 #ifdef COMPAT_FREEBSD32
4587 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
4588 error = fueword32((void *)ptr, &res32);
4589 if (error == 0)
4590 res1 = res32;
4591 } else
4592 #endif
4593 {
4594 error = fueword((void *)ptr, &res1);
4595 }
4596 if (error == 0)
4597 *res = res1;
4598 else
4599 error = EFAULT;
4600 return (error);
4601 }
4602
4603 static void
umtx_read_rb_list(struct thread * td,struct umutex * m,uintptr_t * rb_list)4604 umtx_read_rb_list(struct thread *td, struct umutex *m, uintptr_t *rb_list)
4605 {
4606 #ifdef COMPAT_FREEBSD32
4607 struct umutex32 m32;
4608
4609 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
4610 memcpy(&m32, m, sizeof(m32));
4611 *rb_list = m32.m_rb_lnk;
4612 } else
4613 #endif
4614 *rb_list = m->m_rb_lnk;
4615 }
4616
4617 static int
umtx_handle_rb(struct thread * td,uintptr_t rbp,uintptr_t * rb_list,bool inact)4618 umtx_handle_rb(struct thread *td, uintptr_t rbp, uintptr_t *rb_list, bool inact)
4619 {
4620 struct umutex m;
4621 int error;
4622
4623 KASSERT(td->td_proc == curproc, ("need current vmspace"));
4624 error = copyin((void *)rbp, &m, sizeof(m));
4625 if (error != 0)
4626 return (error);
4627 if (rb_list != NULL)
4628 umtx_read_rb_list(td, &m, rb_list);
4629 if ((m.m_flags & UMUTEX_ROBUST) == 0)
4630 return (EINVAL);
4631 if ((m.m_owner & ~UMUTEX_CONTESTED) != td->td_tid)
4632 /* inact is cleared after unlock, allow the inconsistency */
4633 return (inact ? 0 : EINVAL);
4634 return (do_unlock_umutex(td, (struct umutex *)rbp, true));
4635 }
4636
4637 static void
umtx_cleanup_rb_list(struct thread * td,uintptr_t rb_list,uintptr_t * rb_inact,const char * name)4638 umtx_cleanup_rb_list(struct thread *td, uintptr_t rb_list, uintptr_t *rb_inact,
4639 const char *name)
4640 {
4641 int error, i;
4642 uintptr_t rbp;
4643 bool inact;
4644
4645 if (rb_list == 0)
4646 return;
4647 error = umtx_read_uptr(td, rb_list, &rbp);
4648 for (i = 0; error == 0 && rbp != 0 && i < umtx_max_rb; i++) {
4649 if (rbp == *rb_inact) {
4650 inact = true;
4651 *rb_inact = 0;
4652 } else
4653 inact = false;
4654 error = umtx_handle_rb(td, rbp, &rbp, inact);
4655 }
4656 if (i == umtx_max_rb && umtx_verbose_rb) {
4657 uprintf("comm %s pid %d: reached umtx %smax rb %d\n",
4658 td->td_proc->p_comm, td->td_proc->p_pid, name, umtx_max_rb);
4659 }
4660 if (error != 0 && umtx_verbose_rb) {
4661 uprintf("comm %s pid %d: handling %srb error %d\n",
4662 td->td_proc->p_comm, td->td_proc->p_pid, name, error);
4663 }
4664 }
4665
4666 /*
4667 * Clean up umtx data.
4668 */
4669 static void
umtx_thread_cleanup(struct thread * td)4670 umtx_thread_cleanup(struct thread *td)
4671 {
4672 struct umtx_q *uq;
4673 struct umtx_pi *pi;
4674 uintptr_t rb_inact;
4675
4676 /*
4677 * Disown pi mutexes.
4678 */
4679 uq = td->td_umtxq;
4680 if (uq != NULL) {
4681 mtx_lock(&umtx_lock);
4682 uq->uq_inherited_pri = PRI_MAX;
4683 while ((pi = TAILQ_FIRST(&uq->uq_pi_contested)) != NULL) {
4684 pi->pi_owner = NULL;
4685 TAILQ_REMOVE(&uq->uq_pi_contested, pi, pi_link);
4686 }
4687 mtx_unlock(&umtx_lock);
4688 thread_lock(td);
4689 sched_lend_user_prio(td, PRI_MAX);
4690 thread_unlock(td);
4691 }
4692
4693 /*
4694 * Handle terminated robust mutexes. Must be done after
4695 * robust pi disown, otherwise unlock could see unowned
4696 * entries.
4697 */
4698 rb_inact = td->td_rb_inact;
4699 if (rb_inact != 0)
4700 (void)umtx_read_uptr(td, rb_inact, &rb_inact);
4701 umtx_cleanup_rb_list(td, td->td_rb_list, &rb_inact, "");
4702 umtx_cleanup_rb_list(td, td->td_rbp_list, &rb_inact, "priv ");
4703 if (rb_inact != 0)
4704 (void)umtx_handle_rb(td, rb_inact, NULL, true);
4705 }
4706