1 /* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */
4 * SPDX-License-Identifier: BSD-4-Clause
6 * Copyright (c) 2009-2016 Dmitry Chagin
7 * Copyright (c) 2005 Emmanuel Dreyfus
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * This product includes software developed by Emmanuel Dreyfus
21 * 4. The name of the author may not be used to endorse or promote
22 * products derived from this software without specific prior written
25 * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS''
26 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
27 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $");
44 #include "opt_compat.h"
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/imgact.h>
49 #include <sys/kernel.h>
52 #include <sys/malloc.h>
53 #include <sys/mutex.h>
56 #include <sys/queue.h>
57 #include <sys/sched.h>
61 #include <vm/vm_extern.h>
64 #include <machine/../linux32/linux.h>
65 #include <machine/../linux32/linux32_proto.h>
67 #include <machine/../linux/linux.h>
68 #include <machine/../linux/linux_proto.h>
70 #include <compat/linux/linux_dtrace.h>
71 #include <compat/linux/linux_emul.h>
72 #include <compat/linux/linux_futex.h>
73 #include <compat/linux/linux_timer.h>
74 #include <compat/linux/linux_util.h>
77 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
80 * Futex part for the special DTrace module "locks".
82 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *");
83 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *");
88 LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *");
89 LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *");
92 * DTrace probes in this module.
94 LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *",
95 "struct waiting_proc *");
96 LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t",
98 LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t",
100 LIN_SDT_PROBE_DEFINE0(futex, futex_put, return);
101 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **",
103 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int");
104 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t",
106 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *");
107 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int");
108 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int");
109 LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *",
110 "struct waiting_proc **", "struct futex **");
111 LIN_SDT_PROBE_DEFINE0(futex, futex_get, error);
112 LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int");
113 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *",
114 "struct waiting_proc **", "struct timespec *");
115 LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *",
116 "struct waiting_proc *", "uint32_t *", "uint32_t");
117 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *",
118 "struct waiting_proc *");
119 LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int");
120 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int",
122 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t",
123 "struct waiting_proc *", "uint32_t");
124 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *");
125 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int");
126 LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int",
127 "struct futex *", "int");
128 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *");
129 LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *",
130 "struct waiting_proc *", "uint32_t");
131 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int");
132 LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *",
133 "struct waiting_proc **", "struct timespec *", "uint32_t");
134 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
135 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int");
136 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *",
138 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int",
140 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check);
141 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int");
142 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int");
143 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int");
144 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *",
145 "struct linux_sys_futex_args *");
146 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch);
147 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int");
148 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use);
149 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *",
150 "uint32_t", "uint32_t");
151 LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq,
152 "uint32_t *", "uint32_t", "int", "uint32_t");
153 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *",
154 "uint32_t", "uint32_t");
155 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *",
156 "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *");
157 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq,
159 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *",
160 "int", "uint32_t", "uint32_t *", "uint32_t");
161 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault);
162 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi);
163 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi);
164 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi);
165 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue);
166 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi);
167 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi);
168 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int");
169 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int");
170 LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *",
171 "struct linux_set_robust_list_args *");
172 LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error);
173 LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int");
174 LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *",
175 "struct linux_get_robust_list_args *");
176 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int");
177 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int");
178 LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry,
179 "struct linux_emuldata *", "uint32_t *", "unsigned int");
180 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int");
181 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int");
182 LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry,
183 "struct linux_robust_list **", "struct linux_robust_list **",
185 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");
186 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int");
187 LIN_SDT_PROBE_DEFINE2(futex, release_futexes, entry, "struct thread *",
188 "struct linux_emuldata *");
189 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");
190 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return);
194 struct waiting_proc {
196 struct futex *wp_futex;
197 TAILQ_ENTRY(waiting_proc) wp_list;
202 uint32_t *f_uaddr; /* user-supplied value, for debug */
203 struct umtx_key f_key;
206 LIST_ENTRY(futex) f_list;
207 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
210 struct futex_list futex_list;
212 #define FUTEX_LOCK(f) mtx_lock(&(f)->f_lck)
213 #define FUTEX_LOCKED(f) mtx_owned(&(f)->f_lck)
214 #define FUTEX_UNLOCK(f) mtx_unlock(&(f)->f_lck)
215 #define FUTEX_INIT(f) do { \
216 mtx_init(&(f)->f_lck, "ftlk", NULL, \
218 LIN_SDT_PROBE1(futex, futex, create, \
221 #define FUTEX_DESTROY(f) do { \
222 LIN_SDT_PROBE1(futex, futex, destroy, \
224 mtx_destroy(&(f)->f_lck); \
226 #define FUTEX_ASSERT_LOCKED(f) mtx_assert(&(f)->f_lck, MA_OWNED)
227 #define FUTEX_ASSERT_UNLOCKED(f) mtx_assert(&(f)->f_lck, MA_NOTOWNED)
229 struct mtx futex_mtx; /* protects the futex list */
230 #define FUTEXES_LOCK do { \
231 mtx_lock(&futex_mtx); \
232 LIN_SDT_PROBE1(locks, futex_mtx, \
233 locked, &futex_mtx); \
235 #define FUTEXES_UNLOCK do { \
236 LIN_SDT_PROBE1(locks, futex_mtx, \
237 unlock, &futex_mtx); \
238 mtx_unlock(&futex_mtx); \
241 /* flags for futex_get() */
242 #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */
243 #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */
244 #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */
245 #define FUTEX_SHARED 0x8 /* shared futex */
246 #define FUTEX_DONTLOCK 0x10 /* don't lock futex */
249 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list
250 * of futex where thread sleep to wp_list
253 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex
254 * wp_list to prevent double wakeup.
257 static void futex_put(struct futex *, struct waiting_proc *);
258 static int futex_get0(uint32_t *, struct futex **f, uint32_t);
259 static int futex_get(uint32_t *, struct waiting_proc **, struct futex **,
261 static int futex_sleep(struct futex *, struct waiting_proc *, struct timespec *);
262 static int futex_wake(struct futex *, int, uint32_t);
263 static int futex_requeue(struct futex *, int, struct futex *, int);
264 static int futex_copyin_timeout(int, struct l_timespec *, int,
266 static int futex_wait(struct futex *, struct waiting_proc *, struct timespec *,
268 static void futex_lock(struct futex *);
269 static void futex_unlock(struct futex *);
270 static int futex_atomic_op(struct thread *, int, uint32_t *);
271 static int handle_futex_death(struct linux_emuldata *, uint32_t *,
273 static int fetch_robust_entry(struct linux_robust_list **,
274 struct linux_robust_list **, unsigned int *);
277 futex_copyin_timeout(int op, struct l_timespec *luts, int clockrt,
280 struct l_timespec lts;
284 error = copyin(luts, <s, sizeof(lts));
288 error = linux_to_native_timespec(ts, <s);
293 timespecsub(ts, &kts, ts);
294 } else if (op == LINUX_FUTEX_WAIT_BITSET) {
296 timespecsub(ts, &kts, ts);
302 futex_put(struct futex *f, struct waiting_proc *wp)
304 LIN_SDT_PROBE2(futex, futex_put, entry, f, wp);
307 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
308 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
309 free(wp, M_FUTEX_WP);
313 if (--f->f_refcount == 0) {
314 LIST_REMOVE(f, f_list);
319 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr,
320 f->f_refcount, f->f_key.shared);
321 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
322 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
323 umtx_key_release(&f->f_key);
327 LIN_SDT_PROBE0(futex, futex_put, return);
331 LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount,
333 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
334 f->f_uaddr, f->f_refcount, f->f_key.shared);
339 LIN_SDT_PROBE0(futex, futex_put, return);
343 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
345 struct futex *f, *tmpf;
349 LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags);
353 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
354 AUTO_SHARE : THREAD_SHARE, &key);
356 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error);
357 LIN_SDT_PROBE1(futex, futex_get0, return, error);
362 LIST_FOREACH(f, &futex_list, f_list) {
363 if (umtx_key_match(&f->f_key, &key)) {
365 if (FUTEX_LOCKED(tmpf))
370 if (flags & FUTEX_DONTEXISTS) {
372 umtx_key_release(&key);
374 LIN_SDT_PROBE1(futex, futex_get0, return,
380 * Increment refcount of the found futex to
381 * prevent it from deallocation before FUTEX_LOCK()
385 umtx_key_release(&key);
387 if ((flags & FUTEX_DONTLOCK) == 0)
390 LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr,
391 f->f_refcount, f->f_key.shared);
392 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
393 uaddr, f->f_refcount, f->f_key.shared);
395 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
400 if (flags & FUTEX_DONTCREATE) {
402 umtx_key_release(&key);
403 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr);
404 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
406 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
412 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
413 tmpf->f_uaddr = uaddr;
415 tmpf->f_refcount = 1;
416 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
418 TAILQ_INIT(&tmpf->f_waiting_proc);
421 * Lock the new futex before an insert into the futex_list
422 * to prevent futex usage by other.
424 if ((flags & FUTEX_DONTLOCK) == 0)
429 LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
432 LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount,
434 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
435 uaddr, tmpf->f_refcount, tmpf->f_key.shared);
438 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
443 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
448 LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f);
450 if (flags & FUTEX_CREATE_WP) {
451 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
454 error = futex_get0(uaddr, f, flags);
456 LIN_SDT_PROBE0(futex, futex_get, error);
458 if (flags & FUTEX_CREATE_WP)
459 free(*wp, M_FUTEX_WP);
461 LIN_SDT_PROBE1(futex, futex_get, return, error);
464 if (flags & FUTEX_CREATE_WP) {
465 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
466 (*wp)->wp_futex = *f;
469 LIN_SDT_PROBE1(futex, futex_get, return, error);
474 futex_lock(struct futex *f)
477 LINUX_CTR3(sys_futex, "futex_lock uaddr %p ref %d shared %d",
478 f->f_uaddr, f->f_refcount, f->f_key.shared);
479 FUTEX_ASSERT_UNLOCKED(f);
484 futex_unlock(struct futex *f)
487 LINUX_CTR3(sys_futex, "futex_unlock uaddr %p ref %d shared %d",
488 f->f_uaddr, f->f_refcount, f->f_key.shared);
489 FUTEX_ASSERT_LOCKED(f);
494 futex_sleep(struct futex *f, struct waiting_proc *wp, struct timespec *ts)
497 sbintime_t sbt, prec, tmp;
501 FUTEX_ASSERT_LOCKED(f);
504 if (uts.tv_sec > INT32_MAX / 2) {
505 over = uts.tv_sec - INT32_MAX / 2;
509 if (TIMESEL(&sbt, tmp))
518 LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, sbt);
519 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %ld ref %d",
520 f->f_uaddr, wp, sbt, f->f_refcount);
522 error = msleep_sbt(wp, &f->f_lck, PCATCH, "futex", sbt, prec, C_ABSOLUTE);
523 if (wp->wp_flags & FUTEX_WP_REQUEUED) {
524 KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
527 LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error,
528 f->f_uaddr, wp, wp->wp_futex->f_uaddr,
529 wp->wp_futex->f_refcount);
532 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp"
533 " %p requeued uaddr %p ref %d",
534 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
535 wp->wp_futex->f_refcount);
541 LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error,
544 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
545 error, f->f_uaddr, wp);
550 LIN_SDT_PROBE1(futex, futex_sleep, return, error);
555 futex_wake(struct futex *f, int n, uint32_t bitset)
557 struct waiting_proc *wp, *wpt;
560 LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset);
563 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL);
567 FUTEX_ASSERT_LOCKED(f);
568 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
569 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp,
571 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
572 f->f_uaddr, wp, f->f_refcount);
574 * Unless we find a matching bit in
575 * the bitset, continue searching.
577 if (!(wp->wp_futex->f_bitset & bitset))
580 wp->wp_flags |= FUTEX_WP_REMOVED;
581 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
582 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
588 LIN_SDT_PROBE1(futex, futex_wake, return, count);
593 futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
595 struct waiting_proc *wp, *wpt;
598 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2);
600 FUTEX_ASSERT_LOCKED(f);
601 FUTEX_ASSERT_LOCKED(f2);
603 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
605 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
607 wp->wp_flags |= FUTEX_WP_REMOVED;
608 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
609 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
612 LIN_SDT_PROBE3(futex, futex_requeue, requeue,
613 f->f_uaddr, wp, f2->f_uaddr);
614 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
615 f->f_uaddr, wp, f2->f_uaddr);
616 wp->wp_flags |= FUTEX_WP_REQUEUED;
617 /* Move wp to wp_list of f2 futex */
618 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
619 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
622 * Thread which sleeps on wp after waking should
623 * acquire f2 lock, so increment refcount of f2 to
624 * prevent it from premature deallocation.
635 LIN_SDT_PROBE1(futex, futex_requeue, return, count);
640 futex_wait(struct futex *f, struct waiting_proc *wp, struct timespec *ts,
645 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, ts, bitset);
648 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL);
652 f->f_bitset = bitset;
653 error = futex_sleep(f, wp, ts);
655 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
656 if (error == EWOULDBLOCK)
659 LIN_SDT_PROBE1(futex, futex_wait, return, error);
664 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
666 int op = (encoded_op >> 28) & 7;
667 int cmp = (encoded_op >> 24) & 15;
668 int oparg = (encoded_op << 8) >> 20;
669 int cmparg = (encoded_op << 20) >> 20;
672 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr);
674 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
677 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg,
680 /* XXX: Linux verifies access here and returns EFAULT */
681 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check);
685 ret = futex_xchgl(oparg, uaddr, &oldval);
688 ret = futex_addl(oparg, uaddr, &oldval);
691 ret = futex_orl(oparg, uaddr, &oldval);
694 ret = futex_andl(~oparg, uaddr, &oldval);
697 ret = futex_xorl(oparg, uaddr, &oldval);
700 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op);
706 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
711 case FUTEX_OP_CMP_EQ:
712 ret = (oldval == cmparg);
714 case FUTEX_OP_CMP_NE:
715 ret = (oldval != cmparg);
717 case FUTEX_OP_CMP_LT:
718 ret = (oldval < cmparg);
720 case FUTEX_OP_CMP_GE:
721 ret = (oldval >= cmparg);
723 case FUTEX_OP_CMP_LE:
724 ret = (oldval <= cmparg);
726 case FUTEX_OP_CMP_GT:
727 ret = (oldval > cmparg);
730 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp);
734 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
739 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
741 int clockrt, nrwake, op_ret, ret;
742 struct linux_pemuldata *pem;
743 struct waiting_proc *wp;
744 struct futex *f, *f2;
745 struct timespec uts, *ts;
749 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args);
751 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) {
753 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG;
755 flags = FUTEX_SHARED;
758 * Currently support for switching between CLOCK_MONOTONIC and
759 * CLOCK_REALTIME is not present. However Linux forbids the use of
760 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
761 * FUTEX_WAIT_REQUEUE_PI.
763 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
764 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
765 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
766 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) {
767 LIN_SDT_PROBE0(futex, linux_sys_futex,
768 unimplemented_clockswitch);
769 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
777 case LINUX_FUTEX_WAIT:
778 args->val3 = FUTEX_BITSET_MATCH_ANY;
781 case LINUX_FUTEX_WAIT_BITSET:
782 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr,
783 args->val, args->val3);
784 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x",
785 args->uaddr, args->val, args->val3);
787 if (args->timeout != NULL) {
788 error = futex_copyin_timeout(args->op, args->timeout,
791 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
793 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
801 error = futex_get(args->uaddr, &wp, &f,
802 flags | FUTEX_CREATE_WP);
804 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
808 error = copyin_nofault(args->uaddr, &val, sizeof(val));
811 error = copyin(args->uaddr, &val, sizeof(val));
814 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
816 LINUX_CTR1(sys_futex, "WAIT copyin failed %d",
818 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
821 if (val != args->val) {
822 LIN_SDT_PROBE4(futex, linux_sys_futex,
823 debug_wait_value_neq, args->uaddr, args->val, val,
825 LINUX_CTR3(sys_futex,
826 "WAIT uaddr %p val 0x%x != uval 0x%x",
827 args->uaddr, args->val, val);
830 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
832 return (EWOULDBLOCK);
835 error = futex_wait(f, wp, ts, args->val3);
838 case LINUX_FUTEX_WAKE:
839 args->val3 = FUTEX_BITSET_MATCH_ANY;
842 case LINUX_FUTEX_WAKE_BITSET:
843 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr,
844 args->val, args->val3);
845 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x",
846 args->uaddr, args->val, args->val3);
848 error = futex_get(args->uaddr, NULL, &f,
849 flags | FUTEX_DONTCREATE);
851 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
856 td->td_retval[0] = 0;
858 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
861 td->td_retval[0] = futex_wake(f, args->val, args->val3);
865 case LINUX_FUTEX_CMP_REQUEUE:
866 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue,
867 args->uaddr, args->val, args->val3, args->uaddr2,
869 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
870 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x",
871 args->uaddr, args->val, args->val3, args->uaddr2,
875 * Linux allows this, we would not, it is an incorrect
876 * usage of declared ABI, so return EINVAL.
878 if (args->uaddr == args->uaddr2) {
879 LIN_SDT_PROBE0(futex, linux_sys_futex,
880 invalid_cmp_requeue_use);
881 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
886 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK);
888 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
893 * To avoid deadlocks return EINVAL if second futex
894 * exists at this time.
896 * Glibc fall back to FUTEX_WAKE in case of any error
897 * returned by FUTEX_CMP_REQUEUE.
899 error = futex_get(args->uaddr2, NULL, &f2,
900 flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK);
904 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
909 error = copyin_nofault(args->uaddr, &val, sizeof(val));
913 error = copyin(args->uaddr, &val, sizeof(val));
916 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
918 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
920 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
923 if (val != args->val3) {
924 LIN_SDT_PROBE2(futex, linux_sys_futex,
925 debug_cmp_requeue_value_neq, args->val, val);
926 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x",
931 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN);
935 nrwake = (int)(unsigned long)args->timeout;
936 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake);
941 case LINUX_FUTEX_WAKE_OP:
942 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op,
943 args->uaddr, args->op, args->val, args->uaddr2, args->val3);
944 LINUX_CTR5(sys_futex, "WAKE_OP "
945 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x",
946 args->uaddr, args->val, args->uaddr2, args->val3,
949 if (args->uaddr == args->uaddr2) {
950 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
955 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK);
957 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
961 error = futex_get(args->uaddr2, NULL, &f2, flags | FUTEX_DONTLOCK);
965 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
972 * This function returns positive number as results and
975 save = vm_fault_disable_pagefaults();
976 op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
977 vm_fault_enable_pagefaults(save);
979 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x",
980 args->uaddr, op_ret);
986 error = copyin(args->uaddr2, &val, sizeof(val));
989 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
993 ret = futex_wake(f, args->val, args->val3);
997 nrwake = (int)(unsigned long)args->timeout;
1000 op_ret += futex_wake(f2, nrwake, args->val3);
1002 op_ret += futex_wake(f, nrwake, args->val3);
1007 futex_put(f2, NULL);
1009 td->td_retval[0] = ret;
1012 case LINUX_FUTEX_LOCK_PI:
1013 /* not yet implemented */
1014 pem = pem_find(td->td_proc);
1015 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1018 "unsupported futex_pi op\n");
1019 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1020 LIN_SDT_PROBE0(futex, linux_sys_futex,
1021 unimplemented_lock_pi);
1023 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1026 case LINUX_FUTEX_UNLOCK_PI:
1027 /* not yet implemented */
1028 pem = pem_find(td->td_proc);
1029 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1032 "unsupported futex_pi op\n");
1033 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1034 LIN_SDT_PROBE0(futex, linux_sys_futex,
1035 unimplemented_unlock_pi);
1037 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1040 case LINUX_FUTEX_TRYLOCK_PI:
1041 /* not yet implemented */
1042 pem = pem_find(td->td_proc);
1043 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1046 "unsupported futex_pi op\n");
1047 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1048 LIN_SDT_PROBE0(futex, linux_sys_futex,
1049 unimplemented_trylock_pi);
1051 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1054 case LINUX_FUTEX_REQUEUE:
1056 * Glibc does not use this operation since version 2.3.3,
1057 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
1058 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
1059 * FUTEX_REQUEUE returned EINVAL.
1061 pem = pem_find(td->td_proc);
1062 if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) {
1065 "unsupported futex_requeue op\n");
1066 pem->flags |= LINUX_XDEPR_REQUEUEOP;
1067 LIN_SDT_PROBE0(futex, linux_sys_futex,
1068 deprecated_requeue);
1071 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
1074 case LINUX_FUTEX_WAIT_REQUEUE_PI:
1075 /* not yet implemented */
1076 pem = pem_find(td->td_proc);
1077 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1080 "unsupported futex_pi op\n");
1081 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1082 LIN_SDT_PROBE0(futex, linux_sys_futex,
1083 unimplemented_wait_requeue_pi);
1085 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1088 case LINUX_FUTEX_CMP_REQUEUE_PI:
1089 /* not yet implemented */
1090 pem = pem_find(td->td_proc);
1091 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1094 "unsupported futex_pi op\n");
1095 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1096 LIN_SDT_PROBE0(futex, linux_sys_futex,
1097 unimplemented_cmp_requeue_pi);
1099 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1104 "linux_sys_futex: unknown op %d\n", args->op);
1105 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation,
1107 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1111 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
1116 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args)
1118 struct linux_emuldata *em;
1120 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args);
1122 if (args->len != sizeof(struct linux_robust_list_head)) {
1123 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error);
1124 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL);
1129 em->robust_futexes = args->head;
1131 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0);
1136 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args)
1138 struct linux_emuldata *em;
1139 struct linux_robust_list_head *head;
1140 l_size_t len = sizeof(struct linux_robust_list_head);
1144 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args);
1148 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1149 head = em->robust_futexes;
1151 td2 = tdfind(args->pid, -1);
1153 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1157 if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) {
1158 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1160 PROC_UNLOCK(td2->td_proc);
1165 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1167 if (priv_check(td, PRIV_CRED_SETUID) ||
1168 priv_check(td, PRIV_CRED_SETEUID) ||
1169 p_candebug(td, td2->td_proc)) {
1170 PROC_UNLOCK(td2->td_proc);
1172 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1176 head = em->robust_futexes;
1178 PROC_UNLOCK(td2->td_proc);
1181 error = copyout(&len, args->len, sizeof(l_size_t));
1183 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1185 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT);
1189 error = copyout(&head, args->head, sizeof(head));
1191 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1195 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error);
1200 handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr,
1203 uint32_t uval, nval, mval;
1207 LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi);
1210 error = copyin(uaddr, &uval, 4);
1212 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error);
1213 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT);
1216 if ((uval & FUTEX_TID_MASK) == em->em_tid) {
1217 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
1218 nval = casuword32(uaddr, uval, mval);
1221 LIN_SDT_PROBE1(futex, handle_futex_death, return,
1229 if (!pi && (uval & FUTEX_WAITERS)) {
1230 error = futex_get(uaddr, NULL, &f,
1231 FUTEX_DONTCREATE | FUTEX_SHARED);
1233 LIN_SDT_PROBE1(futex, handle_futex_death,
1238 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
1244 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0);
1249 fetch_robust_entry(struct linux_robust_list **entry,
1250 struct linux_robust_list **head, unsigned int *pi)
1255 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi);
1257 error = copyin((const void *)head, &uentry, sizeof(l_ulong));
1259 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error);
1260 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT);
1264 *entry = (void *)(uentry & ~1UL);
1267 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0);
1271 /* This walks the list of robust futexes releasing them. */
1273 release_futexes(struct thread *td, struct linux_emuldata *em)
1275 struct linux_robust_list_head *head = NULL;
1276 struct linux_robust_list *entry, *next_entry, *pending;
1277 unsigned int limit = 2048, pi, next_pi, pip;
1278 l_long futex_offset;
1281 LIN_SDT_PROBE2(futex, release_futexes, entry, td, em);
1283 head = em->robust_futexes;
1286 LIN_SDT_PROBE0(futex, release_futexes, return);
1290 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) {
1291 LIN_SDT_PROBE0(futex, release_futexes, return);
1295 error = copyin(&head->futex_offset, &futex_offset,
1296 sizeof(futex_offset));
1298 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error);
1299 LIN_SDT_PROBE0(futex, release_futexes, return);
1303 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) {
1304 LIN_SDT_PROBE0(futex, release_futexes, return);
1308 while (entry != &head->list) {
1309 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);
1311 if (entry != pending)
1312 if (handle_futex_death(em,
1313 (uint32_t *)((caddr_t)entry + futex_offset), pi)) {
1314 LIN_SDT_PROBE0(futex, release_futexes, return);
1318 LIN_SDT_PROBE0(futex, release_futexes, return);
1328 sched_relinquish(curthread);
1332 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip);
1334 LIN_SDT_PROBE0(futex, release_futexes, return);