1 /* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */
2
3 /*-
4 * Copyright (c) 2005 Emmanuel Dreyfus, all rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by Emmanuel Dreyfus
17 * 4. The name of the author may not be used to endorse or promote
18 * products derived from this software without specific prior written
19 * permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS''
22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD: releng/9.2/sys/compat/linux/linux_futex.c 246292 2013-02-03 18:37:08Z dchagin $");
36 #if 0
37 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $");
38 #endif
39
40 #include "opt_compat.h"
41 #include "opt_kdtrace.h"
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/imgact.h>
46 #include <sys/kernel.h>
47 #include <sys/ktr.h>
48 #include <sys/lock.h>
49 #include <sys/malloc.h>
50 #include <sys/mutex.h>
51 #include <sys/priv.h>
52 #include <sys/proc.h>
53 #include <sys/queue.h>
54 #include <sys/sched.h>
55 #include <sys/sdt.h>
56 #include <sys/sx.h>
57 #include <sys/umtx.h>
58
59 #ifdef COMPAT_LINUX32
60 #include <machine/../linux32/linux.h>
61 #include <machine/../linux32/linux32_proto.h>
62 #else
63 #include <machine/../linux/linux.h>
64 #include <machine/../linux/linux_proto.h>
65 #endif
66 #include <compat/linux/linux_dtrace.h>
67 #include <compat/linux/linux_emul.h>
68 #include <compat/linux/linux_futex.h>
69 #include <compat/linux/linux_util.h>
70
71 /* DTrace init */
72 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
73
74 /* Linuxulator-global DTrace probes */
75 LIN_SDT_PROBE_DECLARE(locks, emul_lock, locked);
76 LIN_SDT_PROBE_DECLARE(locks, emul_lock, unlock);
77
78 /**
79 * Futex part for the special DTrace module "locks".
80 */
81 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *");
82 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *");
83
84 /**
85 * Per futex probes.
86 */
87 LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *");
88 LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *");
89
90 /**
91 * DTrace probes in this module.
92 */
93 LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *",
94 "struct waiting_proc *");
95 LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t",
96 "int");
97 LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t",
98 "int");
99 LIN_SDT_PROBE_DEFINE0(futex, futex_put, return);
100 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **",
101 "uint32_t");
102 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int");
103 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t",
104 "int");
105 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *");
106 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int");
107 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int");
108 LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *",
109 "struct waiting_proc **", "struct futex **");
110 LIN_SDT_PROBE_DEFINE0(futex, futex_get, error);
111 LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int");
112 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *",
113 "struct waiting_proc **", "int");
114 LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *",
115 "struct waiting_proc *", "uint32_t *", "uint32_t");
116 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *",
117 "struct waiting_proc *");
118 LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int");
119 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int",
120 "uint32_t");
121 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t",
122 "struct waiting_proc *", "uin32_t");
123 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *");
124 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int");
125 LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int",
126 "struct futex *", "int");
127 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *");
128 LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *",
129 "struct waiting_proc *", "uint32_t");
130 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int");
131 LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *",
132 "struct waiting_proc **", "struct l_timespec *", "uint32_t");
133 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, copyin_error, "int");
134 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, itimerfix_error, "int");
135 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
136 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int");
137 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *",
138 "int", "uint32_t");
139 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int",
140 "int");
141 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check);
142 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int");
143 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int");
144 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int");
145 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *",
146 "struct linux_sys_futex_args *");
147 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch);
148 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int");
149 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use);
150 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *",
151 "uint32_t", "uint32_t");
152 LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq,
153 "uint32_t *", "uint32_t", "int", "uint32_t");
154 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *",
155 "uint32_t", "uint32_t");
156 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *",
157 "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *");
158 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq,
159 "uint32_t", "int");
160 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *",
161 "int", "uint32_t", "uint32_t *", "uint32_t");
162 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault);
163 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi);
164 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi);
165 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi);
166 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue);
167 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi);
168 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi);
169 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int");
170 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int");
171 LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *",
172 "struct linux_set_robust_list_args *");
173 LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error);
174 LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int");
175 LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *",
176 "struct linux_get_robust_list_args *");
177 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int");
178 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int");
179 LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry, "struct proc *",
180 "uint32_t *", "int");
181 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int");
182 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int");
183 LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry,
184 "struct linux_robust_list **", "struct linux_robust_list **", "int *");
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_DEFINE1(futex, release_futexes, entry, "struct proc *");
188 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");
189 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return);
190
191 static MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes");
192 static MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futexes wp");
193
194 struct futex;
195
196 struct waiting_proc {
197 uint32_t wp_flags;
198 struct futex *wp_futex;
199 TAILQ_ENTRY(waiting_proc) wp_list;
200 };
201
202 struct futex {
203 struct sx f_lck;
204 uint32_t *f_uaddr; /* user-supplied value, for debug */
205 struct umtx_key f_key;
206 uint32_t f_refcount;
207 uint32_t f_bitset;
208 LIST_ENTRY(futex) f_list;
209 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
210 };
211
212 struct futex_list futex_list;
213
214 #define FUTEX_LOCK(f) sx_xlock(&(f)->f_lck)
215 #define FUTEX_UNLOCK(f) sx_xunlock(&(f)->f_lck)
216 #define FUTEX_INIT(f) do { \
217 sx_init_flags(&(f)->f_lck, "ftlk", \
218 SX_DUPOK); \
219 LIN_SDT_PROBE1(futex, futex, create, \
220 &(f)->f_lck); \
221 } while (0)
222 #define FUTEX_DESTROY(f) do { \
223 LIN_SDT_PROBE1(futex, futex, destroy, \
224 &(f)->f_lck); \
225 sx_destroy(&(f)->f_lck); \
226 } while (0)
227 #define FUTEX_ASSERT_LOCKED(f) sx_assert(&(f)->f_lck, SA_XLOCKED)
228
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); \
234 } while (0)
235 #define FUTEXES_UNLOCK do { \
236 LIN_SDT_PROBE1(locks, futex_mtx, \
237 unlock, &futex_mtx); \
238 mtx_unlock(&futex_mtx); \
239 } while (0)
240
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
247 /* wp_flags */
248 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list
249 * of futex where thread sleep to wp_list
250 * of another futex.
251 */
252 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex
253 * wp_list to prevent double wakeup.
254 */
255
256 /* support.s */
257 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval);
258 int futex_addl(int oparg, uint32_t *uaddr, int *oldval);
259 int futex_orl(int oparg, uint32_t *uaddr, int *oldval);
260 int futex_andl(int oparg, uint32_t *uaddr, int *oldval);
261 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval);
262
263 static void
264 futex_put(struct futex *f, struct waiting_proc *wp)
265 {
266 LIN_SDT_PROBE2(futex, futex_put, entry, f, wp);
267
268 FUTEX_ASSERT_LOCKED(f);
269 if (wp != NULL) {
270 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
271 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
272 free(wp, M_FUTEX_WP);
273 }
274
275 FUTEXES_LOCK;
276 if (--f->f_refcount == 0) {
277 LIST_REMOVE(f, f_list);
278 FUTEXES_UNLOCK;
279 FUTEX_UNLOCK(f);
280
281 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr,
282 f->f_refcount, f->f_key.shared);
283 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
284 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
285 umtx_key_release(&f->f_key);
286 FUTEX_DESTROY(f);
287 free(f, M_FUTEX);
288
289 LIN_SDT_PROBE0(futex, futex_put, return);
290 return;
291 }
292
293 LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount,
294 f->f_key.shared);
295 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
296 f->f_uaddr, f->f_refcount, f->f_key.shared);
297 FUTEXES_UNLOCK;
298 FUTEX_UNLOCK(f);
299
300 LIN_SDT_PROBE0(futex, futex_put, return);
301 }
302
303 static int
304 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
305 {
306 struct futex *f, *tmpf;
307 struct umtx_key key;
308 int error;
309
310 LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags);
311
312 *newf = tmpf = NULL;
313
314 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
315 AUTO_SHARE : THREAD_SHARE, &key);
316 if (error) {
317 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error);
318 LIN_SDT_PROBE1(futex, futex_get0, return, error);
319 return (error);
320 }
321 retry:
322 FUTEXES_LOCK;
323 LIST_FOREACH(f, &futex_list, f_list) {
324 if (umtx_key_match(&f->f_key, &key)) {
325 if (tmpf != NULL) {
326 FUTEX_UNLOCK(tmpf);
327 FUTEX_DESTROY(tmpf);
328 free(tmpf, M_FUTEX);
329 }
330 if (flags & FUTEX_DONTEXISTS) {
331 FUTEXES_UNLOCK;
332 umtx_key_release(&key);
333
334 LIN_SDT_PROBE1(futex, futex_get0, return,
335 EINVAL);
336 return (EINVAL);
337 }
338
339 /*
340 * Increment refcount of the found futex to
341 * prevent it from deallocation before FUTEX_LOCK()
342 */
343 ++f->f_refcount;
344 FUTEXES_UNLOCK;
345 umtx_key_release(&key);
346
347 FUTEX_LOCK(f);
348 *newf = f;
349 LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr,
350 f->f_refcount, f->f_key.shared);
351 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
352 uaddr, f->f_refcount, f->f_key.shared);
353
354 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
355 return (0);
356 }
357 }
358
359 if (flags & FUTEX_DONTCREATE) {
360 FUTEXES_UNLOCK;
361 umtx_key_release(&key);
362 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr);
363 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
364
365 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
366 return (0);
367 }
368
369 if (tmpf == NULL) {
370 FUTEXES_UNLOCK;
371 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
372 tmpf->f_uaddr = uaddr;
373 tmpf->f_key = key;
374 tmpf->f_refcount = 1;
375 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
376 FUTEX_INIT(tmpf);
377 TAILQ_INIT(&tmpf->f_waiting_proc);
378
379 /*
380 * Lock the new futex before an insert into the futex_list
381 * to prevent futex usage by other.
382 */
383 FUTEX_LOCK(tmpf);
384 goto retry;
385 }
386
387 LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
388 FUTEXES_UNLOCK;
389
390 LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount,
391 tmpf->f_key.shared);
392 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
393 uaddr, tmpf->f_refcount, tmpf->f_key.shared);
394 *newf = tmpf;
395
396 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
397 return (0);
398 }
399
400 static int
401 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
402 uint32_t flags)
403 {
404 int error;
405
406 LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f);
407
408 if (flags & FUTEX_CREATE_WP) {
409 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
410 (*wp)->wp_flags = 0;
411 }
412 error = futex_get0(uaddr, f, flags);
413 if (error) {
414 LIN_SDT_PROBE0(futex, futex_get, error);
415
416 if (flags & FUTEX_CREATE_WP)
417 free(*wp, M_FUTEX_WP);
418
419 LIN_SDT_PROBE1(futex, futex_get, return, error);
420 return (error);
421 }
422 if (flags & FUTEX_CREATE_WP) {
423 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
424 (*wp)->wp_futex = *f;
425 }
426
427 LIN_SDT_PROBE1(futex, futex_get, return, error);
428 return (error);
429 }
430
431 static int
432 futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout)
433 {
434 int error;
435
436 FUTEX_ASSERT_LOCKED(f);
437 LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, timeout);
438 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d",
439 f->f_uaddr, wp, timeout, f->f_refcount);
440 error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout);
441 if (wp->wp_flags & FUTEX_WP_REQUEUED) {
442 KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
443
444 if (error) {
445 LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error,
446 f->f_uaddr, wp, wp->wp_futex->f_uaddr,
447 wp->wp_futex->f_refcount);
448 }
449
450 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp"
451 " %p requeued uaddr %p ref %d",
452 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
453 wp->wp_futex->f_refcount);
454 futex_put(f, NULL);
455 f = wp->wp_futex;
456 FUTEX_LOCK(f);
457 } else {
458 if (error) {
459 LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error,
460 f->f_uaddr, wp);
461 }
462 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
463 error, f->f_uaddr, wp);
464 }
465
466 futex_put(f, wp);
467
468 LIN_SDT_PROBE1(futex, futex_sleep, return, error);
469 return (error);
470 }
471
472 static int
473 futex_wake(struct futex *f, int n, uint32_t bitset)
474 {
475 struct waiting_proc *wp, *wpt;
476 int count = 0;
477
478 LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset);
479
480 if (bitset == 0) {
481 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL);
482 return (EINVAL);
483 }
484
485 FUTEX_ASSERT_LOCKED(f);
486 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
487 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp,
488 f->f_refcount);
489 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
490 f->f_uaddr, wp, f->f_refcount);
491 /*
492 * Unless we find a matching bit in
493 * the bitset, continue searching.
494 */
495 if (!(wp->wp_futex->f_bitset & bitset))
496 continue;
497
498 wp->wp_flags |= FUTEX_WP_REMOVED;
499 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
500 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
501 wakeup_one(wp);
502 if (++count == n)
503 break;
504 }
505
506 LIN_SDT_PROBE1(futex, futex_wake, return, count);
507 return (count);
508 }
509
510 static int
511 futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
512 {
513 struct waiting_proc *wp, *wpt;
514 int count = 0;
515
516 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2);
517
518 FUTEX_ASSERT_LOCKED(f);
519 FUTEX_ASSERT_LOCKED(f2);
520
521 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
522 if (++count <= n) {
523 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
524 f->f_uaddr, wp);
525 wp->wp_flags |= FUTEX_WP_REMOVED;
526 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
527 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
528 wakeup_one(wp);
529 } else {
530 LIN_SDT_PROBE3(futex, futex_requeue, requeue,
531 f->f_uaddr, wp, f2->f_uaddr);
532 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
533 f->f_uaddr, wp, f2->f_uaddr);
534 wp->wp_flags |= FUTEX_WP_REQUEUED;
535 /* Move wp to wp_list of f2 futex */
536 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
537 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
538
539 /*
540 * Thread which sleeps on wp after waking should
541 * acquire f2 lock, so increment refcount of f2 to
542 * prevent it from premature deallocation.
543 */
544 wp->wp_futex = f2;
545 FUTEXES_LOCK;
546 ++f2->f_refcount;
547 FUTEXES_UNLOCK;
548 if (count - n >= n2)
549 break;
550 }
551 }
552
553 LIN_SDT_PROBE1(futex, futex_requeue, return, count);
554 return (count);
555 }
556
557 static int
558 futex_wait(struct futex *f, struct waiting_proc *wp, struct l_timespec *ts,
559 uint32_t bitset)
560 {
561 struct l_timespec timeout;
562 struct timeval tv;
563 int timeout_hz;
564 int error;
565
566 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, ts, bitset);
567
568 if (bitset == 0) {
569 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL);
570 return (EINVAL);
571 }
572
573 f->f_bitset = bitset;
574
575 if (ts != NULL) {
576 error = copyin(ts, &timeout, sizeof(timeout));
577 if (error) {
578 LIN_SDT_PROBE1(futex, futex_wait, copyin_error, error);
579 LIN_SDT_PROBE1(futex, futex_wait, return, error);
580 return (error);
581 }
582 TIMESPEC_TO_TIMEVAL(&tv, &timeout);
583 error = itimerfix(&tv);
584 if (error) {
585 LIN_SDT_PROBE1(futex, futex_wait, itimerfix_error,
586 error);
587 LIN_SDT_PROBE1(futex, futex_wait, return, error);
588 return (error);
589 }
590 timeout_hz = tvtohz(&tv);
591 } else
592 timeout_hz = 0;
593
594 error = futex_sleep(f, wp, timeout_hz);
595 if (error) {
596 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
597 }
598 if (error == EWOULDBLOCK)
599 error = ETIMEDOUT;
600
601 LIN_SDT_PROBE1(futex, futex_wait, return, error);
602 return (error);
603 }
604
605 static int
606 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
607 {
608 int op = (encoded_op >> 28) & 7;
609 int cmp = (encoded_op >> 24) & 15;
610 int oparg = (encoded_op << 8) >> 20;
611 int cmparg = (encoded_op << 20) >> 20;
612 int oldval = 0, ret;
613
614 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr);
615
616 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
617 oparg = 1 << oparg;
618
619 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg,
620 cmparg);
621
622 /* XXX: Linux verifies access here and returns EFAULT */
623 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check);
624
625 switch (op) {
626 case FUTEX_OP_SET:
627 ret = futex_xchgl(oparg, uaddr, &oldval);
628 break;
629 case FUTEX_OP_ADD:
630 ret = futex_addl(oparg, uaddr, &oldval);
631 break;
632 case FUTEX_OP_OR:
633 ret = futex_orl(oparg, uaddr, &oldval);
634 break;
635 case FUTEX_OP_ANDN:
636 ret = futex_andl(~oparg, uaddr, &oldval);
637 break;
638 case FUTEX_OP_XOR:
639 ret = futex_xorl(oparg, uaddr, &oldval);
640 break;
641 default:
642 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op);
643 ret = -ENOSYS;
644 break;
645 }
646
647 if (ret) {
648 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
649 return (ret);
650 }
651
652 switch (cmp) {
653 case FUTEX_OP_CMP_EQ:
654 ret = (oldval == cmparg);
655 break;
656 case FUTEX_OP_CMP_NE:
657 ret = (oldval != cmparg);
658 break;
659 case FUTEX_OP_CMP_LT:
660 ret = (oldval < cmparg);
661 break;
662 case FUTEX_OP_CMP_GE:
663 ret = (oldval >= cmparg);
664 break;
665 case FUTEX_OP_CMP_LE:
666 ret = (oldval <= cmparg);
667 break;
668 case FUTEX_OP_CMP_GT:
669 ret = (oldval > cmparg);
670 break;
671 default:
672 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp);
673 ret = -ENOSYS;
674 }
675
676 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
677 return (ret);
678 }
679
680 int
681 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
682 {
683 int clockrt, nrwake, op_ret, ret, val;
684 struct linux_emuldata *em;
685 struct waiting_proc *wp;
686 struct futex *f, *f2;
687 int error;
688 uint32_t flags;
689
690 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args);
691
692 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) {
693 flags = 0;
694 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG;
695 } else
696 flags = FUTEX_SHARED;
697
698 /*
699 * Currently support for switching between CLOCK_MONOTONIC and
700 * CLOCK_REALTIME is not present. However Linux forbids the use of
701 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
702 * FUTEX_WAIT_REQUEUE_PI.
703 */
704 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
705 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
706 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
707 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) {
708 LIN_SDT_PROBE0(futex, linux_sys_futex,
709 unimplemented_clockswitch);
710 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
711 return (ENOSYS);
712 }
713
714 error = 0;
715 f = f2 = NULL;
716
717 switch (args->op) {
718 case LINUX_FUTEX_WAIT:
719 args->val3 = FUTEX_BITSET_MATCH_ANY;
720 /* FALLTHROUGH */
721
722 case LINUX_FUTEX_WAIT_BITSET:
723 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr,
724 args->val, args->val3);
725 LINUX_CTR3(sys_futex, "WAIT uaddr %p val %d val3 %d",
726 args->uaddr, args->val, args->val3);
727
728 error = futex_get(args->uaddr, &wp, &f,
729 flags | FUTEX_CREATE_WP);
730 if (error) {
731 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
732 return (error);
733 }
734
735 error = copyin(args->uaddr, &val, sizeof(val));
736 if (error) {
737 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
738 error);
739 LINUX_CTR1(sys_futex, "WAIT copyin failed %d",
740 error);
741 futex_put(f, wp);
742
743 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
744 return (error);
745 }
746 if (val != args->val) {
747 LIN_SDT_PROBE4(futex, linux_sys_futex,
748 debug_wait_value_neq, args->uaddr, args->val, val,
749 args->val3);
750 LINUX_CTR4(sys_futex,
751 "WAIT uaddr %p val %d != uval %d val3 %d",
752 args->uaddr, args->val, val, args->val3);
753 futex_put(f, wp);
754
755 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
756 EWOULDBLOCK);
757 return (EWOULDBLOCK);
758 }
759
760 error = futex_wait(f, wp, args->timeout, args->val3);
761 break;
762
763 case LINUX_FUTEX_WAKE:
764 args->val3 = FUTEX_BITSET_MATCH_ANY;
765 /* FALLTHROUGH */
766
767 case LINUX_FUTEX_WAKE_BITSET:
768 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr,
769 args->val, args->val3);
770 LINUX_CTR3(sys_futex, "WAKE uaddr %p val % d val3 %d",
771 args->uaddr, args->val, args->val3);
772
773 error = futex_get(args->uaddr, NULL, &f,
774 flags | FUTEX_DONTCREATE);
775 if (error) {
776 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
777 return (error);
778 }
779
780 if (f == NULL) {
781 td->td_retval[0] = 0;
782
783 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
784 return (error);
785 }
786 td->td_retval[0] = futex_wake(f, args->val, args->val3);
787 futex_put(f, NULL);
788 break;
789
790 case LINUX_FUTEX_CMP_REQUEUE:
791 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue,
792 args->uaddr, args->val, args->val3, args->uaddr2,
793 args->timeout);
794 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
795 "val %d val3 %d uaddr2 %p val2 %d",
796 args->uaddr, args->val, args->val3, args->uaddr2,
797 (int)(unsigned long)args->timeout);
798
799 /*
800 * Linux allows this, we would not, it is an incorrect
801 * usage of declared ABI, so return EINVAL.
802 */
803 if (args->uaddr == args->uaddr2) {
804 LIN_SDT_PROBE0(futex, linux_sys_futex,
805 invalid_cmp_requeue_use);
806 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
807 return (EINVAL);
808 }
809
810 error = futex_get(args->uaddr, NULL, &f, flags);
811 if (error) {
812 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
813 return (error);
814 }
815
816 /*
817 * To avoid deadlocks return EINVAL if second futex
818 * exists at this time.
819 *
820 * Glibc fall back to FUTEX_WAKE in case of any error
821 * returned by FUTEX_CMP_REQUEUE.
822 */
823 error = futex_get(args->uaddr2, NULL, &f2,
824 flags | FUTEX_DONTEXISTS);
825 if (error) {
826 futex_put(f, NULL);
827
828 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
829 return (error);
830 }
831 error = copyin(args->uaddr, &val, sizeof(val));
832 if (error) {
833 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
834 error);
835 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
836 error);
837 futex_put(f2, NULL);
838 futex_put(f, NULL);
839
840 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
841 return (error);
842 }
843 if (val != args->val3) {
844 LIN_SDT_PROBE2(futex, linux_sys_futex,
845 debug_cmp_requeue_value_neq, args->val, val);
846 LINUX_CTR2(sys_futex, "CMP_REQUEUE val %d != uval %d",
847 args->val, val);
848 futex_put(f2, NULL);
849 futex_put(f, NULL);
850
851 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN);
852 return (EAGAIN);
853 }
854
855 nrwake = (int)(unsigned long)args->timeout;
856 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake);
857 futex_put(f2, NULL);
858 futex_put(f, NULL);
859 break;
860
861 case LINUX_FUTEX_WAKE_OP:
862 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op,
863 args->uaddr, args->op, args->val, args->uaddr2, args->val3);
864 LINUX_CTR5(sys_futex, "WAKE_OP "
865 "uaddr %p op %d val %x uaddr2 %p val3 %x",
866 args->uaddr, args->op, args->val,
867 args->uaddr2, args->val3);
868
869 error = futex_get(args->uaddr, NULL, &f, flags);
870 if (error) {
871 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
872 return (error);
873 }
874
875 if (args->uaddr != args->uaddr2)
876 error = futex_get(args->uaddr2, NULL, &f2, flags);
877 if (error) {
878 futex_put(f, NULL);
879
880 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
881 return (error);
882 }
883
884 /*
885 * This function returns positive number as results and
886 * negative as errors
887 */
888 op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
889
890 if (op_ret < 0) {
891 /* XXX: We don't handle the EFAULT yet. */
892 if (op_ret != -EFAULT) {
893 if (f2 != NULL)
894 futex_put(f2, NULL);
895 futex_put(f, NULL);
896
897 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
898 -op_ret);
899 return (-op_ret);
900 } else {
901 LIN_SDT_PROBE0(futex, linux_sys_futex,
902 unhandled_efault);
903 }
904 if (f2 != NULL)
905 futex_put(f2, NULL);
906 futex_put(f, NULL);
907
908 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EFAULT);
909 return (EFAULT);
910 }
911
912 ret = futex_wake(f, args->val, args->val3);
913
914 if (op_ret > 0) {
915 op_ret = 0;
916 nrwake = (int)(unsigned long)args->timeout;
917
918 if (f2 != NULL)
919 op_ret += futex_wake(f2, nrwake, args->val3);
920 else
921 op_ret += futex_wake(f, nrwake, args->val3);
922 ret += op_ret;
923
924 }
925 if (f2 != NULL)
926 futex_put(f2, NULL);
927 futex_put(f, NULL);
928 td->td_retval[0] = ret;
929 break;
930
931 case LINUX_FUTEX_LOCK_PI:
932 /* not yet implemented */
933 linux_msg(td,
934 "linux_sys_futex: "
935 "op LINUX_FUTEX_LOCK_PI not implemented\n");
936 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_lock_pi);
937 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
938 return (ENOSYS);
939
940 case LINUX_FUTEX_UNLOCK_PI:
941 /* not yet implemented */
942 linux_msg(td,
943 "linux_sys_futex: "
944 "op LINUX_FUTEX_UNLOCK_PI not implemented\n");
945 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_unlock_pi);
946 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
947 return (ENOSYS);
948
949 case LINUX_FUTEX_TRYLOCK_PI:
950 /* not yet implemented */
951 linux_msg(td,
952 "linux_sys_futex: "
953 "op LINUX_FUTEX_TRYLOCK_PI not implemented\n");
954 LIN_SDT_PROBE0(futex, linux_sys_futex,
955 unimplemented_trylock_pi);
956 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
957 return (ENOSYS);
958
959 case LINUX_FUTEX_REQUEUE:
960
961 /*
962 * Glibc does not use this operation since version 2.3.3,
963 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
964 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
965 * FUTEX_REQUEUE returned EINVAL.
966 */
967 em = em_find(td->td_proc, EMUL_DONTLOCK);
968 if ((em->flags & LINUX_XDEPR_REQUEUEOP) == 0) {
969 linux_msg(td,
970 "linux_sys_futex: "
971 "unsupported futex_requeue op\n");
972 em->flags |= LINUX_XDEPR_REQUEUEOP;
973 LIN_SDT_PROBE0(futex, linux_sys_futex,
974 deprecated_requeue);
975 }
976
977 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
978 return (EINVAL);
979
980 case LINUX_FUTEX_WAIT_REQUEUE_PI:
981 /* not yet implemented */
982 linux_msg(td,
983 "linux_sys_futex: "
984 "op FUTEX_WAIT_REQUEUE_PI not implemented\n");
985 LIN_SDT_PROBE0(futex, linux_sys_futex,
986 unimplemented_wait_requeue_pi);
987 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
988 return (ENOSYS);
989
990 case LINUX_FUTEX_CMP_REQUEUE_PI:
991 /* not yet implemented */
992 linux_msg(td,
993 "linux_sys_futex: "
994 "op LINUX_FUTEX_CMP_REQUEUE_PI not implemented\n");
995 LIN_SDT_PROBE0(futex, linux_sys_futex,
996 unimplemented_cmp_requeue_pi);
997 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
998 return (ENOSYS);
999
1000 default:
1001 linux_msg(td,
1002 "linux_sys_futex: unknown op %d\n", args->op);
1003 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation,
1004 args->op);
1005 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1006 return (ENOSYS);
1007 }
1008
1009 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
1010 return (error);
1011 }
1012
1013 int
1014 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args)
1015 {
1016 struct linux_emuldata *em;
1017
1018 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args);
1019
1020 if (args->len != sizeof(struct linux_robust_list_head)) {
1021 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error);
1022 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL);
1023 return (EINVAL);
1024 }
1025
1026 em = em_find(td->td_proc, EMUL_DOLOCK);
1027 em->robust_futexes = args->head;
1028 EMUL_UNLOCK(&emul_lock);
1029
1030 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0);
1031 return (0);
1032 }
1033
1034 int
1035 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args)
1036 {
1037 struct linux_emuldata *em;
1038 struct linux_robust_list_head *head;
1039 l_size_t len = sizeof(struct linux_robust_list_head);
1040 int error = 0;
1041
1042 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args);
1043
1044 if (!args->pid) {
1045 em = em_find(td->td_proc, EMUL_DONTLOCK);
1046 head = em->robust_futexes;
1047 } else {
1048 struct proc *p;
1049
1050 p = pfind(args->pid);
1051 if (p == NULL) {
1052 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1053 ESRCH);
1054 return (ESRCH);
1055 }
1056
1057 em = em_find(p, EMUL_DONTLOCK);
1058 /* XXX: ptrace? */
1059 if (priv_check(td, PRIV_CRED_SETUID) ||
1060 priv_check(td, PRIV_CRED_SETEUID) ||
1061 p_candebug(td, p)) {
1062 PROC_UNLOCK(p);
1063
1064 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1065 EPERM);
1066 return (EPERM);
1067 }
1068 head = em->robust_futexes;
1069
1070 PROC_UNLOCK(p);
1071 }
1072
1073 error = copyout(&len, args->len, sizeof(l_size_t));
1074 if (error) {
1075 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1076 error);
1077 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT);
1078 return (EFAULT);
1079 }
1080
1081 error = copyout(head, args->head, sizeof(struct linux_robust_list_head));
1082 if (error) {
1083 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1084 error);
1085 }
1086
1087 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error);
1088 return (error);
1089 }
1090
1091 static int
1092 handle_futex_death(struct proc *p, uint32_t *uaddr, int pi)
1093 {
1094 uint32_t uval, nval, mval;
1095 struct futex *f;
1096 int error;
1097
1098 LIN_SDT_PROBE3(futex, handle_futex_death, entry, p, uaddr, pi);
1099
1100 retry:
1101 error = copyin(uaddr, &uval, 4);
1102 if (error) {
1103 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error);
1104 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT);
1105 return (EFAULT);
1106 }
1107 if ((uval & FUTEX_TID_MASK) == p->p_pid) {
1108 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
1109 nval = casuword32(uaddr, uval, mval);
1110
1111 if (nval == -1) {
1112 LIN_SDT_PROBE1(futex, handle_futex_death, return,
1113 EFAULT);
1114 return (EFAULT);
1115 }
1116
1117 if (nval != uval)
1118 goto retry;
1119
1120 if (!pi && (uval & FUTEX_WAITERS)) {
1121 error = futex_get(uaddr, NULL, &f,
1122 FUTEX_DONTCREATE | FUTEX_SHARED);
1123 if (error) {
1124 LIN_SDT_PROBE1(futex, handle_futex_death,
1125 return, error);
1126 return (error);
1127 }
1128 if (f != NULL) {
1129 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
1130 futex_put(f, NULL);
1131 }
1132 }
1133 }
1134
1135 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0);
1136 return (0);
1137 }
1138
1139 static int
1140 fetch_robust_entry(struct linux_robust_list **entry,
1141 struct linux_robust_list **head, int *pi)
1142 {
1143 l_ulong uentry;
1144 int error;
1145
1146 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi);
1147
1148 error = copyin((const void *)head, &uentry, sizeof(l_ulong));
1149 if (error) {
1150 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error);
1151 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT);
1152 return (EFAULT);
1153 }
1154
1155 *entry = (void *)(uentry & ~1UL);
1156 *pi = uentry & 1;
1157
1158 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0);
1159 return (0);
1160 }
1161
1162 /* This walks the list of robust futexes releasing them. */
1163 void
1164 release_futexes(struct proc *p)
1165 {
1166 struct linux_robust_list_head *head = NULL;
1167 struct linux_robust_list *entry, *next_entry, *pending;
1168 unsigned int limit = 2048, pi, next_pi, pip;
1169 struct linux_emuldata *em;
1170 l_long futex_offset;
1171 int rc, error;
1172
1173 LIN_SDT_PROBE1(futex, release_futexes, entry, p);
1174
1175 em = em_find(p, EMUL_DONTLOCK);
1176 head = em->robust_futexes;
1177
1178 if (head == NULL) {
1179 LIN_SDT_PROBE0(futex, release_futexes, return);
1180 return;
1181 }
1182
1183 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) {
1184 LIN_SDT_PROBE0(futex, release_futexes, return);
1185 return;
1186 }
1187
1188 error = copyin(&head->futex_offset, &futex_offset,
1189 sizeof(futex_offset));
1190 if (error) {
1191 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error);
1192 LIN_SDT_PROBE0(futex, release_futexes, return);
1193 return;
1194 }
1195
1196 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) {
1197 LIN_SDT_PROBE0(futex, release_futexes, return);
1198 return;
1199 }
1200
1201 while (entry != &head->list) {
1202 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);
1203
1204 if (entry != pending)
1205 if (handle_futex_death(p,
1206 (uint32_t *)((caddr_t)entry + futex_offset), pi)) {
1207 LIN_SDT_PROBE0(futex, release_futexes, return);
1208 return;
1209 }
1210 if (rc) {
1211 LIN_SDT_PROBE0(futex, release_futexes, return);
1212 return;
1213 }
1214
1215 entry = next_entry;
1216 pi = next_pi;
1217
1218 if (!--limit)
1219 break;
1220
1221 sched_relinquish(curthread);
1222 }
1223
1224 if (pending)
1225 handle_futex_death(p, (uint32_t *)((caddr_t)pending + futex_offset), pip);
1226
1227 LIN_SDT_PROBE0(futex, release_futexes, return);
1228 }
Cache object: a8cea5bf990df6fc638e093de598ec5f
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