1 /* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */
4 * Copyright (c) 2009-2016 Dmitry Chagin
5 * Copyright (c) 2005 Emmanuel Dreyfus
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by Emmanuel Dreyfus
19 * 4. The name of the author may not be used to endorse or promote
20 * products derived from this software without specific prior written
23 * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS''
24 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
25 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
26 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
27 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
28 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
30 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
31 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
32 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33 * POSSIBILITY OF SUCH DAMAGE.
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
39 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $");
42 #include "opt_compat.h"
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/imgact.h>
47 #include <sys/kernel.h>
50 #include <sys/malloc.h>
51 #include <sys/mutex.h>
54 #include <sys/queue.h>
55 #include <sys/sched.h>
59 #include <vm/vm_extern.h>
62 #include <machine/../linux32/linux.h>
63 #include <machine/../linux32/linux32_proto.h>
65 #include <machine/../linux/linux.h>
66 #include <machine/../linux/linux_proto.h>
68 #include <compat/linux/linux_dtrace.h>
69 #include <compat/linux/linux_emul.h>
70 #include <compat/linux/linux_futex.h>
71 #include <compat/linux/linux_timer.h>
72 #include <compat/linux/linux_util.h>
75 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
78 * Futex part for the special DTrace module "locks".
80 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *");
81 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *");
86 LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *");
87 LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *");
90 * DTrace probes in this module.
92 LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *",
93 "struct waiting_proc *");
94 LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t",
96 LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t",
98 LIN_SDT_PROBE_DEFINE0(futex, futex_put, return);
99 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **",
101 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int");
102 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t",
104 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *");
105 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int");
106 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int");
107 LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *",
108 "struct waiting_proc **", "struct futex **");
109 LIN_SDT_PROBE_DEFINE0(futex, futex_get, error);
110 LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int");
111 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *",
112 "struct waiting_proc **", "struct timespec *");
113 LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *",
114 "struct waiting_proc *", "uint32_t *", "uint32_t");
115 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *",
116 "struct waiting_proc *");
117 LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int");
118 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int",
120 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t",
121 "struct waiting_proc *", "uint32_t");
122 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *");
123 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int");
124 LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int",
125 "struct futex *", "int");
126 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *");
127 LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *",
128 "struct waiting_proc *", "uint32_t");
129 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int");
130 LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *",
131 "struct waiting_proc **", "struct timespec *", "uint32_t");
132 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
133 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int");
134 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *",
136 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int",
138 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check);
139 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int");
140 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int");
141 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int");
142 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *",
143 "struct linux_sys_futex_args *");
144 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch);
145 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int");
146 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use);
147 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *",
148 "uint32_t", "uint32_t");
149 LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq,
150 "uint32_t *", "uint32_t", "int", "uint32_t");
151 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *",
152 "uint32_t", "uint32_t");
153 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *",
154 "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *");
155 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq,
157 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *",
158 "int", "uint32_t", "uint32_t *", "uint32_t");
159 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault);
160 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi);
161 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi);
162 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi);
163 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue);
164 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi);
165 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi);
166 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int");
167 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int");
168 LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *",
169 "struct linux_set_robust_list_args *");
170 LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error);
171 LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int");
172 LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *",
173 "struct linux_get_robust_list_args *");
174 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int");
175 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int");
176 LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry,
177 "struct linux_emuldata *", "uint32_t *", "unsigned int");
178 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int");
179 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int");
180 LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry,
181 "struct linux_robust_list **", "struct linux_robust_list **",
183 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");
184 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int");
185 LIN_SDT_PROBE_DEFINE2(futex, release_futexes, entry, "struct thread *",
186 "struct linux_emuldata *");
187 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");
188 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return);
192 struct waiting_proc {
194 struct futex *wp_futex;
195 TAILQ_ENTRY(waiting_proc) wp_list;
200 uint32_t *f_uaddr; /* user-supplied value, for debug */
201 struct umtx_key f_key;
204 LIST_ENTRY(futex) f_list;
205 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
208 struct futex_list futex_list;
210 #define FUTEX_LOCK(f) mtx_lock(&(f)->f_lck)
211 #define FUTEX_LOCKED(f) mtx_owned(&(f)->f_lck)
212 #define FUTEX_UNLOCK(f) mtx_unlock(&(f)->f_lck)
213 #define FUTEX_INIT(f) do { \
214 mtx_init(&(f)->f_lck, "ftlk", NULL, \
216 LIN_SDT_PROBE1(futex, futex, create, \
219 #define FUTEX_DESTROY(f) do { \
220 LIN_SDT_PROBE1(futex, futex, destroy, \
222 mtx_destroy(&(f)->f_lck); \
224 #define FUTEX_ASSERT_LOCKED(f) mtx_assert(&(f)->f_lck, MA_OWNED)
225 #define FUTEX_ASSERT_UNLOCKED(f) mtx_assert(&(f)->f_lck, MA_NOTOWNED)
227 struct mtx futex_mtx; /* protects the futex list */
228 #define FUTEXES_LOCK do { \
229 mtx_lock(&futex_mtx); \
230 LIN_SDT_PROBE1(locks, futex_mtx, \
231 locked, &futex_mtx); \
233 #define FUTEXES_UNLOCK do { \
234 LIN_SDT_PROBE1(locks, futex_mtx, \
235 unlock, &futex_mtx); \
236 mtx_unlock(&futex_mtx); \
239 /* flags for futex_get() */
240 #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */
241 #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */
242 #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */
243 #define FUTEX_SHARED 0x8 /* shared futex */
244 #define FUTEX_DONTLOCK 0x10 /* don't lock futex */
247 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list
248 * of futex where thread sleep to wp_list
251 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex
252 * wp_list to prevent double wakeup.
255 static void futex_put(struct futex *, struct waiting_proc *);
256 static int futex_get0(uint32_t *, struct futex **f, uint32_t);
257 static int futex_get(uint32_t *, struct waiting_proc **, struct futex **,
259 static int futex_sleep(struct futex *, struct waiting_proc *, struct timespec *);
260 static int futex_wake(struct futex *, int, uint32_t);
261 static int futex_requeue(struct futex *, int, struct futex *, int);
262 static int futex_copyin_timeout(int, struct l_timespec *, int,
264 static int futex_wait(struct futex *, struct waiting_proc *, struct timespec *,
266 static void futex_lock(struct futex *);
267 static void futex_unlock(struct futex *);
268 static int futex_atomic_op(struct thread *, int, uint32_t *);
269 static int handle_futex_death(struct linux_emuldata *, uint32_t *,
271 static int fetch_robust_entry(struct linux_robust_list **,
272 struct linux_robust_list **, unsigned int *);
275 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval);
276 int futex_addl(int oparg, uint32_t *uaddr, int *oldval);
277 int futex_orl(int oparg, uint32_t *uaddr, int *oldval);
278 int futex_andl(int oparg, uint32_t *uaddr, int *oldval);
279 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval);
283 futex_copyin_timeout(int op, struct l_timespec *luts, int clockrt,
286 struct l_timespec lts;
290 error = copyin(luts, <s, sizeof(lts));
294 error = linux_to_native_timespec(ts, <s);
299 timespecsub(ts, &kts);
300 } else if (op == LINUX_FUTEX_WAIT_BITSET) {
302 timespecsub(ts, &kts);
308 futex_put(struct futex *f, struct waiting_proc *wp)
310 LIN_SDT_PROBE2(futex, futex_put, entry, f, wp);
313 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
314 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
315 free(wp, M_FUTEX_WP);
319 if (--f->f_refcount == 0) {
320 LIST_REMOVE(f, f_list);
325 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr,
326 f->f_refcount, f->f_key.shared);
327 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
328 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
329 umtx_key_release(&f->f_key);
333 LIN_SDT_PROBE0(futex, futex_put, return);
337 LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount,
339 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
340 f->f_uaddr, f->f_refcount, f->f_key.shared);
345 LIN_SDT_PROBE0(futex, futex_put, return);
349 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
351 struct futex *f, *tmpf;
355 LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags);
359 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
360 AUTO_SHARE : THREAD_SHARE, &key);
362 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error);
363 LIN_SDT_PROBE1(futex, futex_get0, return, error);
368 LIST_FOREACH(f, &futex_list, f_list) {
369 if (umtx_key_match(&f->f_key, &key)) {
371 if (FUTEX_LOCKED(tmpf))
376 if (flags & FUTEX_DONTEXISTS) {
378 umtx_key_release(&key);
380 LIN_SDT_PROBE1(futex, futex_get0, return,
386 * Increment refcount of the found futex to
387 * prevent it from deallocation before FUTEX_LOCK()
391 umtx_key_release(&key);
393 if ((flags & FUTEX_DONTLOCK) == 0)
396 LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr,
397 f->f_refcount, f->f_key.shared);
398 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
399 uaddr, f->f_refcount, f->f_key.shared);
401 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
406 if (flags & FUTEX_DONTCREATE) {
408 umtx_key_release(&key);
409 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr);
410 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
412 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
418 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
419 tmpf->f_uaddr = uaddr;
421 tmpf->f_refcount = 1;
422 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
424 TAILQ_INIT(&tmpf->f_waiting_proc);
427 * Lock the new futex before an insert into the futex_list
428 * to prevent futex usage by other.
430 if ((flags & FUTEX_DONTLOCK) == 0)
435 LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
438 LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount,
440 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
441 uaddr, tmpf->f_refcount, tmpf->f_key.shared);
444 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
449 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
454 LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f);
456 if (flags & FUTEX_CREATE_WP) {
457 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
460 error = futex_get0(uaddr, f, flags);
462 LIN_SDT_PROBE0(futex, futex_get, error);
464 if (flags & FUTEX_CREATE_WP)
465 free(*wp, M_FUTEX_WP);
467 LIN_SDT_PROBE1(futex, futex_get, return, error);
470 if (flags & FUTEX_CREATE_WP) {
471 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
472 (*wp)->wp_futex = *f;
475 LIN_SDT_PROBE1(futex, futex_get, return, error);
480 futex_lock(struct futex *f)
483 LINUX_CTR3(sys_futex, "futex_lock uaddr %p ref %d shared %d",
484 f->f_uaddr, f->f_refcount, f->f_key.shared);
485 FUTEX_ASSERT_UNLOCKED(f);
490 futex_unlock(struct futex *f)
493 LINUX_CTR3(sys_futex, "futex_unlock uaddr %p ref %d shared %d",
494 f->f_uaddr, f->f_refcount, f->f_key.shared);
495 FUTEX_ASSERT_LOCKED(f);
500 futex_sleep(struct futex *f, struct waiting_proc *wp, struct timespec *ts)
503 sbintime_t sbt, prec, tmp;
507 FUTEX_ASSERT_LOCKED(f);
510 if (uts.tv_sec > INT32_MAX / 2) {
511 over = uts.tv_sec - INT32_MAX / 2;
515 if (TIMESEL(&sbt, tmp))
524 LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, sbt);
525 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %ld ref %d",
526 f->f_uaddr, wp, sbt, f->f_refcount);
528 error = msleep_sbt(wp, &f->f_lck, PCATCH, "futex", sbt, prec, C_ABSOLUTE);
529 if (wp->wp_flags & FUTEX_WP_REQUEUED) {
530 KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
533 LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error,
534 f->f_uaddr, wp, wp->wp_futex->f_uaddr,
535 wp->wp_futex->f_refcount);
538 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp"
539 " %p requeued uaddr %p ref %d",
540 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
541 wp->wp_futex->f_refcount);
547 LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error,
550 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
551 error, f->f_uaddr, wp);
556 LIN_SDT_PROBE1(futex, futex_sleep, return, error);
561 futex_wake(struct futex *f, int n, uint32_t bitset)
563 struct waiting_proc *wp, *wpt;
566 LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset);
569 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL);
573 FUTEX_ASSERT_LOCKED(f);
574 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
575 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp,
577 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
578 f->f_uaddr, wp, f->f_refcount);
580 * Unless we find a matching bit in
581 * the bitset, continue searching.
583 if (!(wp->wp_futex->f_bitset & bitset))
586 wp->wp_flags |= FUTEX_WP_REMOVED;
587 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
588 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
594 LIN_SDT_PROBE1(futex, futex_wake, return, count);
599 futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
601 struct waiting_proc *wp, *wpt;
604 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2);
606 FUTEX_ASSERT_LOCKED(f);
607 FUTEX_ASSERT_LOCKED(f2);
609 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
611 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
613 wp->wp_flags |= FUTEX_WP_REMOVED;
614 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
615 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
618 LIN_SDT_PROBE3(futex, futex_requeue, requeue,
619 f->f_uaddr, wp, f2->f_uaddr);
620 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
621 f->f_uaddr, wp, f2->f_uaddr);
622 wp->wp_flags |= FUTEX_WP_REQUEUED;
623 /* Move wp to wp_list of f2 futex */
624 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
625 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
628 * Thread which sleeps on wp after waking should
629 * acquire f2 lock, so increment refcount of f2 to
630 * prevent it from premature deallocation.
641 LIN_SDT_PROBE1(futex, futex_requeue, return, count);
646 futex_wait(struct futex *f, struct waiting_proc *wp, struct timespec *ts,
651 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, ts, bitset);
654 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL);
658 f->f_bitset = bitset;
659 error = futex_sleep(f, wp, ts);
661 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
662 if (error == EWOULDBLOCK)
665 LIN_SDT_PROBE1(futex, futex_wait, return, error);
670 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
672 int op = (encoded_op >> 28) & 7;
673 int cmp = (encoded_op >> 24) & 15;
674 int oparg = (encoded_op << 8) >> 20;
675 int cmparg = (encoded_op << 20) >> 20;
678 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr);
680 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
683 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg,
686 /* XXX: Linux verifies access here and returns EFAULT */
687 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check);
691 ret = futex_xchgl(oparg, uaddr, &oldval);
694 ret = futex_addl(oparg, uaddr, &oldval);
697 ret = futex_orl(oparg, uaddr, &oldval);
700 ret = futex_andl(~oparg, uaddr, &oldval);
703 ret = futex_xorl(oparg, uaddr, &oldval);
706 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op);
712 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
717 case FUTEX_OP_CMP_EQ:
718 ret = (oldval == cmparg);
720 case FUTEX_OP_CMP_NE:
721 ret = (oldval != cmparg);
723 case FUTEX_OP_CMP_LT:
724 ret = (oldval < cmparg);
726 case FUTEX_OP_CMP_GE:
727 ret = (oldval >= cmparg);
729 case FUTEX_OP_CMP_LE:
730 ret = (oldval <= cmparg);
732 case FUTEX_OP_CMP_GT:
733 ret = (oldval > cmparg);
736 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp);
740 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
745 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
747 int clockrt, nrwake, op_ret, ret;
748 struct linux_pemuldata *pem;
749 struct waiting_proc *wp;
750 struct futex *f, *f2;
751 struct timespec uts, *ts;
755 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args);
757 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) {
759 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG;
761 flags = FUTEX_SHARED;
764 * Currently support for switching between CLOCK_MONOTONIC and
765 * CLOCK_REALTIME is not present. However Linux forbids the use of
766 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
767 * FUTEX_WAIT_REQUEUE_PI.
769 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
770 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
771 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
772 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) {
773 LIN_SDT_PROBE0(futex, linux_sys_futex,
774 unimplemented_clockswitch);
775 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
783 case LINUX_FUTEX_WAIT:
784 args->val3 = FUTEX_BITSET_MATCH_ANY;
787 case LINUX_FUTEX_WAIT_BITSET:
788 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr,
789 args->val, args->val3);
790 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x",
791 args->uaddr, args->val, args->val3);
793 if (args->timeout != NULL) {
794 error = futex_copyin_timeout(args->op, args->timeout,
797 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
799 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
807 error = futex_get(args->uaddr, &wp, &f,
808 flags | FUTEX_CREATE_WP);
810 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
814 error = copyin_nofault(args->uaddr, &val, sizeof(val));
817 error = copyin(args->uaddr, &val, sizeof(val));
820 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
822 LINUX_CTR1(sys_futex, "WAIT copyin failed %d",
824 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
827 if (val != args->val) {
828 LIN_SDT_PROBE4(futex, linux_sys_futex,
829 debug_wait_value_neq, args->uaddr, args->val, val,
831 LINUX_CTR3(sys_futex,
832 "WAIT uaddr %p val 0x%x != uval 0x%x",
833 args->uaddr, args->val, val);
836 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
838 return (EWOULDBLOCK);
841 error = futex_wait(f, wp, ts, args->val3);
844 case LINUX_FUTEX_WAKE:
845 args->val3 = FUTEX_BITSET_MATCH_ANY;
848 case LINUX_FUTEX_WAKE_BITSET:
849 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr,
850 args->val, args->val3);
851 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x",
852 args->uaddr, args->val, args->val3);
854 error = futex_get(args->uaddr, NULL, &f,
855 flags | FUTEX_DONTCREATE);
857 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
862 td->td_retval[0] = 0;
864 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
867 td->td_retval[0] = futex_wake(f, args->val, args->val3);
871 case LINUX_FUTEX_CMP_REQUEUE:
872 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue,
873 args->uaddr, args->val, args->val3, args->uaddr2,
875 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
876 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x",
877 args->uaddr, args->val, args->val3, args->uaddr2,
881 * Linux allows this, we would not, it is an incorrect
882 * usage of declared ABI, so return EINVAL.
884 if (args->uaddr == args->uaddr2) {
885 LIN_SDT_PROBE0(futex, linux_sys_futex,
886 invalid_cmp_requeue_use);
887 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
892 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK);
894 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
899 * To avoid deadlocks return EINVAL if second futex
900 * exists at this time.
902 * Glibc fall back to FUTEX_WAKE in case of any error
903 * returned by FUTEX_CMP_REQUEUE.
905 error = futex_get(args->uaddr2, NULL, &f2,
906 flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK);
910 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
915 error = copyin_nofault(args->uaddr, &val, sizeof(val));
919 error = copyin(args->uaddr, &val, sizeof(val));
922 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
924 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
926 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
929 if (val != args->val3) {
930 LIN_SDT_PROBE2(futex, linux_sys_futex,
931 debug_cmp_requeue_value_neq, args->val, val);
932 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x",
937 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN);
941 nrwake = (int)(unsigned long)args->timeout;
942 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake);
947 case LINUX_FUTEX_WAKE_OP:
948 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op,
949 args->uaddr, args->op, args->val, args->uaddr2, args->val3);
950 LINUX_CTR5(sys_futex, "WAKE_OP "
951 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x",
952 args->uaddr, args->val, args->uaddr2, args->val3,
956 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK);
958 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
962 if (args->uaddr != args->uaddr2)
963 error = futex_get(args->uaddr2, NULL, &f2,
964 flags | FUTEX_DONTLOCK);
968 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
975 * This function returns positive number as results and
978 save = vm_fault_disable_pagefaults();
979 op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
980 vm_fault_enable_pagefaults(save);
982 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x",
983 args->uaddr, op_ret);
989 error = copyin(args->uaddr2, &val, sizeof(val));
992 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
996 ret = futex_wake(f, args->val, args->val3);
1000 nrwake = (int)(unsigned long)args->timeout;
1003 op_ret += futex_wake(f2, nrwake, args->val3);
1005 op_ret += futex_wake(f, nrwake, args->val3);
1010 futex_put(f2, NULL);
1012 td->td_retval[0] = ret;
1015 case LINUX_FUTEX_LOCK_PI:
1016 /* not yet implemented */
1017 pem = pem_find(td->td_proc);
1018 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1021 "unsupported futex_pi op\n");
1022 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1023 LIN_SDT_PROBE0(futex, linux_sys_futex,
1024 unimplemented_lock_pi);
1026 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1029 case LINUX_FUTEX_UNLOCK_PI:
1030 /* not yet implemented */
1031 pem = pem_find(td->td_proc);
1032 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1035 "unsupported futex_pi op\n");
1036 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1037 LIN_SDT_PROBE0(futex, linux_sys_futex,
1038 unimplemented_unlock_pi);
1040 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1043 case LINUX_FUTEX_TRYLOCK_PI:
1044 /* not yet implemented */
1045 pem = pem_find(td->td_proc);
1046 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1049 "unsupported futex_pi op\n");
1050 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1051 LIN_SDT_PROBE0(futex, linux_sys_futex,
1052 unimplemented_trylock_pi);
1054 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1057 case LINUX_FUTEX_REQUEUE:
1059 * Glibc does not use this operation since version 2.3.3,
1060 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
1061 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
1062 * FUTEX_REQUEUE returned EINVAL.
1064 pem = pem_find(td->td_proc);
1065 if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) {
1068 "unsupported futex_requeue op\n");
1069 pem->flags |= LINUX_XDEPR_REQUEUEOP;
1070 LIN_SDT_PROBE0(futex, linux_sys_futex,
1071 deprecated_requeue);
1074 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
1077 case LINUX_FUTEX_WAIT_REQUEUE_PI:
1078 /* not yet implemented */
1079 pem = pem_find(td->td_proc);
1080 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1083 "unsupported futex_pi op\n");
1084 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1085 LIN_SDT_PROBE0(futex, linux_sys_futex,
1086 unimplemented_wait_requeue_pi);
1088 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1091 case LINUX_FUTEX_CMP_REQUEUE_PI:
1092 /* not yet implemented */
1093 pem = pem_find(td->td_proc);
1094 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) {
1097 "unsupported futex_pi op\n");
1098 pem->flags |= LINUX_XUNSUP_FUTEXPIOP;
1099 LIN_SDT_PROBE0(futex, linux_sys_futex,
1100 unimplemented_cmp_requeue_pi);
1102 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1107 "linux_sys_futex: unknown op %d\n", args->op);
1108 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation,
1110 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1114 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
1119 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args)
1121 struct linux_emuldata *em;
1123 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args);
1125 if (args->len != sizeof(struct linux_robust_list_head)) {
1126 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error);
1127 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL);
1132 em->robust_futexes = args->head;
1134 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0);
1139 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args)
1141 struct linux_emuldata *em;
1142 struct linux_robust_list_head *head;
1143 l_size_t len = sizeof(struct linux_robust_list_head);
1147 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args);
1151 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1152 head = em->robust_futexes;
1154 td2 = tdfind(args->pid, -1);
1156 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1160 if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) {
1161 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1163 PROC_UNLOCK(td2->td_proc);
1168 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n"));
1170 if (priv_check(td, PRIV_CRED_SETUID) ||
1171 priv_check(td, PRIV_CRED_SETEUID) ||
1172 p_candebug(td, td2->td_proc)) {
1173 PROC_UNLOCK(td2->td_proc);
1175 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1179 head = em->robust_futexes;
1181 PROC_UNLOCK(td2->td_proc);
1184 error = copyout(&len, args->len, sizeof(l_size_t));
1186 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1188 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT);
1192 error = copyout(&head, args->head, sizeof(head));
1194 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1198 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error);
1203 handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr,
1206 uint32_t uval, nval, mval;
1210 LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi);
1213 error = copyin(uaddr, &uval, 4);
1215 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error);
1216 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT);
1219 if ((uval & FUTEX_TID_MASK) == em->em_tid) {
1220 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
1221 nval = casuword32(uaddr, uval, mval);
1224 LIN_SDT_PROBE1(futex, handle_futex_death, return,
1232 if (!pi && (uval & FUTEX_WAITERS)) {
1233 error = futex_get(uaddr, NULL, &f,
1234 FUTEX_DONTCREATE | FUTEX_SHARED);
1236 LIN_SDT_PROBE1(futex, handle_futex_death,
1241 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
1247 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0);
1252 fetch_robust_entry(struct linux_robust_list **entry,
1253 struct linux_robust_list **head, unsigned int *pi)
1258 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi);
1260 error = copyin((const void *)head, &uentry, sizeof(l_ulong));
1262 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error);
1263 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT);
1267 *entry = (void *)(uentry & ~1UL);
1270 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0);
1274 /* This walks the list of robust futexes releasing them. */
1276 release_futexes(struct thread *td, struct linux_emuldata *em)
1278 struct linux_robust_list_head *head = NULL;
1279 struct linux_robust_list *entry, *next_entry, *pending;
1280 unsigned int limit = 2048, pi, next_pi, pip;
1281 l_long futex_offset;
1284 LIN_SDT_PROBE2(futex, release_futexes, entry, td, em);
1286 head = em->robust_futexes;
1289 LIN_SDT_PROBE0(futex, release_futexes, return);
1293 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) {
1294 LIN_SDT_PROBE0(futex, release_futexes, return);
1298 error = copyin(&head->futex_offset, &futex_offset,
1299 sizeof(futex_offset));
1301 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error);
1302 LIN_SDT_PROBE0(futex, release_futexes, return);
1306 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) {
1307 LIN_SDT_PROBE0(futex, release_futexes, return);
1311 while (entry != &head->list) {
1312 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);
1314 if (entry != pending)
1315 if (handle_futex_death(em,
1316 (uint32_t *)((caddr_t)entry + futex_offset), pi)) {
1317 LIN_SDT_PROBE0(futex, release_futexes, return);
1321 LIN_SDT_PROBE0(futex, release_futexes, return);
1331 sched_relinquish(curthread);
1335 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip);
1337 LIN_SDT_PROBE0(futex, release_futexes, return);