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/10.1/sys/compat/linux/linux_futex.c 293894 2016-01-14 09:11:16Z glebius $");
36 #if 0
37 __KERNEL_RCSID(1, "$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 *", "uint32_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 **", "int", "uint32_t");
133 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int");
134 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int");
135 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *",
136 "int", "uint32_t");
137 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int",
138 "int");
139 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check);
140 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int");
141 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int");
142 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int");
143 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *",
144 "struct linux_sys_futex_args *");
145 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch);
146 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, itimerfix_error, "int");
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,
158 "uint32_t", "int");
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, "struct proc *",
179 "uint32_t *", "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 **", "int *");
184 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int");
185 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int");
186 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, entry, "struct proc *");
187 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int");
188 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return);
189
190 static MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes");
191 static MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futexes wp");
192
193 struct futex;
194
195 struct waiting_proc {
196 uint32_t wp_flags;
197 struct futex *wp_futex;
198 TAILQ_ENTRY(waiting_proc) wp_list;
199 };
200
201 struct futex {
202 struct sx f_lck;
203 uint32_t *f_uaddr; /* user-supplied value, for debug */
204 struct umtx_key f_key;
205 uint32_t f_refcount;
206 uint32_t f_bitset;
207 LIST_ENTRY(futex) f_list;
208 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc;
209 };
210
211 struct futex_list futex_list;
212
213 #define FUTEX_LOCK(f) sx_xlock(&(f)->f_lck)
214 #define FUTEX_UNLOCK(f) sx_xunlock(&(f)->f_lck)
215 #define FUTEX_INIT(f) do { \
216 sx_init_flags(&(f)->f_lck, "ftlk", \
217 SX_DUPOK); \
218 LIN_SDT_PROBE1(futex, futex, create, \
219 &(f)->f_lck); \
220 } while (0)
221 #define FUTEX_DESTROY(f) do { \
222 LIN_SDT_PROBE1(futex, futex, destroy, \
223 &(f)->f_lck); \
224 sx_destroy(&(f)->f_lck); \
225 } while (0)
226 #define FUTEX_ASSERT_LOCKED(f) sx_assert(&(f)->f_lck, SA_XLOCKED)
227
228 struct mtx futex_mtx; /* protects the futex list */
229 #define FUTEXES_LOCK do { \
230 mtx_lock(&futex_mtx); \
231 LIN_SDT_PROBE1(locks, futex_mtx, \
232 locked, &futex_mtx); \
233 } while (0)
234 #define FUTEXES_UNLOCK do { \
235 LIN_SDT_PROBE1(locks, futex_mtx, \
236 unlock, &futex_mtx); \
237 mtx_unlock(&futex_mtx); \
238 } while (0)
239
240 /* flags for futex_get() */
241 #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */
242 #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */
243 #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */
244 #define FUTEX_SHARED 0x8 /* shared futex */
245
246 /* wp_flags */
247 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list
248 * of futex where thread sleep to wp_list
249 * of another futex.
250 */
251 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex
252 * wp_list to prevent double wakeup.
253 */
254
255 /* support.s */
256 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval);
257 int futex_addl(int oparg, uint32_t *uaddr, int *oldval);
258 int futex_orl(int oparg, uint32_t *uaddr, int *oldval);
259 int futex_andl(int oparg, uint32_t *uaddr, int *oldval);
260 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval);
261
262 static void
263 futex_put(struct futex *f, struct waiting_proc *wp)
264 {
265 LIN_SDT_PROBE2(futex, futex_put, entry, f, wp);
266
267 FUTEX_ASSERT_LOCKED(f);
268 if (wp != NULL) {
269 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0)
270 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
271 free(wp, M_FUTEX_WP);
272 }
273
274 FUTEXES_LOCK;
275 if (--f->f_refcount == 0) {
276 LIST_REMOVE(f, f_list);
277 FUTEXES_UNLOCK;
278 FUTEX_UNLOCK(f);
279
280 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr,
281 f->f_refcount, f->f_key.shared);
282 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d "
283 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared);
284 umtx_key_release(&f->f_key);
285 FUTEX_DESTROY(f);
286 free(f, M_FUTEX);
287
288 LIN_SDT_PROBE0(futex, futex_put, return);
289 return;
290 }
291
292 LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount,
293 f->f_key.shared);
294 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d",
295 f->f_uaddr, f->f_refcount, f->f_key.shared);
296 FUTEXES_UNLOCK;
297 FUTEX_UNLOCK(f);
298
299 LIN_SDT_PROBE0(futex, futex_put, return);
300 }
301
302 static int
303 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags)
304 {
305 struct futex *f, *tmpf;
306 struct umtx_key key;
307 int error;
308
309 LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags);
310
311 *newf = tmpf = NULL;
312
313 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ?
314 AUTO_SHARE : THREAD_SHARE, &key);
315 if (error) {
316 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error);
317 LIN_SDT_PROBE1(futex, futex_get0, return, error);
318 return (error);
319 }
320 retry:
321 FUTEXES_LOCK;
322 LIST_FOREACH(f, &futex_list, f_list) {
323 if (umtx_key_match(&f->f_key, &key)) {
324 if (tmpf != NULL) {
325 FUTEX_UNLOCK(tmpf);
326 FUTEX_DESTROY(tmpf);
327 free(tmpf, M_FUTEX);
328 }
329 if (flags & FUTEX_DONTEXISTS) {
330 FUTEXES_UNLOCK;
331 umtx_key_release(&key);
332
333 LIN_SDT_PROBE1(futex, futex_get0, return,
334 EINVAL);
335 return (EINVAL);
336 }
337
338 /*
339 * Increment refcount of the found futex to
340 * prevent it from deallocation before FUTEX_LOCK()
341 */
342 ++f->f_refcount;
343 FUTEXES_UNLOCK;
344 umtx_key_release(&key);
345
346 FUTEX_LOCK(f);
347 *newf = f;
348 LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr,
349 f->f_refcount, f->f_key.shared);
350 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d",
351 uaddr, f->f_refcount, f->f_key.shared);
352
353 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
354 return (0);
355 }
356 }
357
358 if (flags & FUTEX_DONTCREATE) {
359 FUTEXES_UNLOCK;
360 umtx_key_release(&key);
361 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr);
362 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr);
363
364 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
365 return (0);
366 }
367
368 if (tmpf == NULL) {
369 FUTEXES_UNLOCK;
370 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO);
371 tmpf->f_uaddr = uaddr;
372 tmpf->f_key = key;
373 tmpf->f_refcount = 1;
374 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY;
375 FUTEX_INIT(tmpf);
376 TAILQ_INIT(&tmpf->f_waiting_proc);
377
378 /*
379 * Lock the new futex before an insert into the futex_list
380 * to prevent futex usage by other.
381 */
382 FUTEX_LOCK(tmpf);
383 goto retry;
384 }
385
386 LIST_INSERT_HEAD(&futex_list, tmpf, f_list);
387 FUTEXES_UNLOCK;
388
389 LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount,
390 tmpf->f_key.shared);
391 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new",
392 uaddr, tmpf->f_refcount, tmpf->f_key.shared);
393 *newf = tmpf;
394
395 LIN_SDT_PROBE1(futex, futex_get0, return, 0);
396 return (0);
397 }
398
399 static int
400 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f,
401 uint32_t flags)
402 {
403 int error;
404
405 LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f);
406
407 if (flags & FUTEX_CREATE_WP) {
408 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK);
409 (*wp)->wp_flags = 0;
410 }
411 error = futex_get0(uaddr, f, flags);
412 if (error) {
413 LIN_SDT_PROBE0(futex, futex_get, error);
414
415 if (flags & FUTEX_CREATE_WP)
416 free(*wp, M_FUTEX_WP);
417
418 LIN_SDT_PROBE1(futex, futex_get, return, error);
419 return (error);
420 }
421 if (flags & FUTEX_CREATE_WP) {
422 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list);
423 (*wp)->wp_futex = *f;
424 }
425
426 LIN_SDT_PROBE1(futex, futex_get, return, error);
427 return (error);
428 }
429
430 static int
431 futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout)
432 {
433 int error;
434
435 FUTEX_ASSERT_LOCKED(f);
436 LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, timeout);
437 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d",
438 f->f_uaddr, wp, timeout, f->f_refcount);
439 error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout);
440 if (wp->wp_flags & FUTEX_WP_REQUEUED) {
441 KASSERT(f != wp->wp_futex, ("futex != wp_futex"));
442
443 if (error) {
444 LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error,
445 f->f_uaddr, wp, wp->wp_futex->f_uaddr,
446 wp->wp_futex->f_refcount);
447 }
448
449 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp"
450 " %p requeued uaddr %p ref %d",
451 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr,
452 wp->wp_futex->f_refcount);
453 futex_put(f, NULL);
454 f = wp->wp_futex;
455 FUTEX_LOCK(f);
456 } else {
457 if (error) {
458 LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error,
459 f->f_uaddr, wp);
460 }
461 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p",
462 error, f->f_uaddr, wp);
463 }
464
465 futex_put(f, wp);
466
467 LIN_SDT_PROBE1(futex, futex_sleep, return, error);
468 return (error);
469 }
470
471 static int
472 futex_wake(struct futex *f, int n, uint32_t bitset)
473 {
474 struct waiting_proc *wp, *wpt;
475 int count = 0;
476
477 LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset);
478
479 if (bitset == 0) {
480 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL);
481 return (EINVAL);
482 }
483
484 FUTEX_ASSERT_LOCKED(f);
485 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
486 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp,
487 f->f_refcount);
488 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d",
489 f->f_uaddr, wp, f->f_refcount);
490 /*
491 * Unless we find a matching bit in
492 * the bitset, continue searching.
493 */
494 if (!(wp->wp_futex->f_bitset & bitset))
495 continue;
496
497 wp->wp_flags |= FUTEX_WP_REMOVED;
498 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
499 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp);
500 wakeup_one(wp);
501 if (++count == n)
502 break;
503 }
504
505 LIN_SDT_PROBE1(futex, futex_wake, return, count);
506 return (count);
507 }
508
509 static int
510 futex_requeue(struct futex *f, int n, struct futex *f2, int n2)
511 {
512 struct waiting_proc *wp, *wpt;
513 int count = 0;
514
515 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2);
516
517 FUTEX_ASSERT_LOCKED(f);
518 FUTEX_ASSERT_LOCKED(f2);
519
520 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) {
521 if (++count <= n) {
522 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p",
523 f->f_uaddr, wp);
524 wp->wp_flags |= FUTEX_WP_REMOVED;
525 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
526 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp);
527 wakeup_one(wp);
528 } else {
529 LIN_SDT_PROBE3(futex, futex_requeue, requeue,
530 f->f_uaddr, wp, f2->f_uaddr);
531 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p",
532 f->f_uaddr, wp, f2->f_uaddr);
533 wp->wp_flags |= FUTEX_WP_REQUEUED;
534 /* Move wp to wp_list of f2 futex */
535 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list);
536 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list);
537
538 /*
539 * Thread which sleeps on wp after waking should
540 * acquire f2 lock, so increment refcount of f2 to
541 * prevent it from premature deallocation.
542 */
543 wp->wp_futex = f2;
544 FUTEXES_LOCK;
545 ++f2->f_refcount;
546 FUTEXES_UNLOCK;
547 if (count - n >= n2)
548 break;
549 }
550 }
551
552 LIN_SDT_PROBE1(futex, futex_requeue, return, count);
553 return (count);
554 }
555
556 static int
557 futex_wait(struct futex *f, struct waiting_proc *wp, int timeout_hz,
558 uint32_t bitset)
559 {
560 int error;
561
562 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, timeout_hz, bitset);
563
564 if (bitset == 0) {
565 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL);
566 return (EINVAL);
567 }
568
569 f->f_bitset = bitset;
570 error = futex_sleep(f, wp, timeout_hz);
571 if (error)
572 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error);
573 if (error == EWOULDBLOCK)
574 error = ETIMEDOUT;
575
576 LIN_SDT_PROBE1(futex, futex_wait, return, error);
577 return (error);
578 }
579
580 static int
581 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr)
582 {
583 int op = (encoded_op >> 28) & 7;
584 int cmp = (encoded_op >> 24) & 15;
585 int oparg = (encoded_op << 8) >> 20;
586 int cmparg = (encoded_op << 20) >> 20;
587 int oldval = 0, ret;
588
589 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr);
590
591 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
592 oparg = 1 << oparg;
593
594 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg,
595 cmparg);
596
597 /* XXX: Linux verifies access here and returns EFAULT */
598 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check);
599
600 switch (op) {
601 case FUTEX_OP_SET:
602 ret = futex_xchgl(oparg, uaddr, &oldval);
603 break;
604 case FUTEX_OP_ADD:
605 ret = futex_addl(oparg, uaddr, &oldval);
606 break;
607 case FUTEX_OP_OR:
608 ret = futex_orl(oparg, uaddr, &oldval);
609 break;
610 case FUTEX_OP_ANDN:
611 ret = futex_andl(~oparg, uaddr, &oldval);
612 break;
613 case FUTEX_OP_XOR:
614 ret = futex_xorl(oparg, uaddr, &oldval);
615 break;
616 default:
617 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op);
618 ret = -ENOSYS;
619 break;
620 }
621
622 if (ret) {
623 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
624 return (ret);
625 }
626
627 switch (cmp) {
628 case FUTEX_OP_CMP_EQ:
629 ret = (oldval == cmparg);
630 break;
631 case FUTEX_OP_CMP_NE:
632 ret = (oldval != cmparg);
633 break;
634 case FUTEX_OP_CMP_LT:
635 ret = (oldval < cmparg);
636 break;
637 case FUTEX_OP_CMP_GE:
638 ret = (oldval >= cmparg);
639 break;
640 case FUTEX_OP_CMP_LE:
641 ret = (oldval <= cmparg);
642 break;
643 case FUTEX_OP_CMP_GT:
644 ret = (oldval > cmparg);
645 break;
646 default:
647 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp);
648 ret = -ENOSYS;
649 }
650
651 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret);
652 return (ret);
653 }
654
655 int
656 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args)
657 {
658 int clockrt, nrwake, op_ret, ret;
659 struct linux_emuldata *em;
660 struct waiting_proc *wp;
661 struct futex *f, *f2;
662 struct l_timespec timeout;
663 struct timeval utv, ctv;
664 int timeout_hz;
665 int error;
666 uint32_t flags, val;
667
668 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args);
669
670 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) {
671 flags = 0;
672 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG;
673 } else
674 flags = FUTEX_SHARED;
675
676 /*
677 * Currently support for switching between CLOCK_MONOTONIC and
678 * CLOCK_REALTIME is not present. However Linux forbids the use of
679 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and
680 * FUTEX_WAIT_REQUEUE_PI.
681 */
682 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME;
683 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME;
684 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET &&
685 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) {
686 LIN_SDT_PROBE0(futex, linux_sys_futex,
687 unimplemented_clockswitch);
688 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
689 return (ENOSYS);
690 }
691
692 error = 0;
693 f = f2 = NULL;
694
695 switch (args->op) {
696 case LINUX_FUTEX_WAIT:
697 args->val3 = FUTEX_BITSET_MATCH_ANY;
698 /* FALLTHROUGH */
699
700 case LINUX_FUTEX_WAIT_BITSET:
701 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr,
702 args->val, args->val3);
703 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x",
704 args->uaddr, args->val, args->val3);
705
706 error = futex_get(args->uaddr, &wp, &f,
707 flags | FUTEX_CREATE_WP);
708 if (error) {
709 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
710 return (error);
711 }
712
713 error = copyin(args->uaddr, &val, sizeof(val));
714 if (error) {
715 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
716 error);
717 LINUX_CTR1(sys_futex, "WAIT copyin failed %d",
718 error);
719 futex_put(f, wp);
720
721 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
722 return (error);
723 }
724 if (val != args->val) {
725 LIN_SDT_PROBE4(futex, linux_sys_futex,
726 debug_wait_value_neq, args->uaddr, args->val, val,
727 args->val3);
728 LINUX_CTR3(sys_futex,
729 "WAIT uaddr %p val 0x%x != uval 0x%x",
730 args->uaddr, args->val, val);
731 futex_put(f, wp);
732
733 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
734 EWOULDBLOCK);
735 return (EWOULDBLOCK);
736 }
737
738 if (args->timeout != NULL) {
739 error = copyin(args->timeout, &timeout, sizeof(timeout));
740 if (error) {
741 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
742 error);
743 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
744 futex_put(f, wp);
745 return (error);
746 }
747 TIMESPEC_TO_TIMEVAL(&utv, &timeout);
748 error = itimerfix(&utv);
749 if (error) {
750 LIN_SDT_PROBE1(futex, linux_sys_futex, itimerfix_error,
751 error);
752 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
753 futex_put(f, wp);
754 return (error);
755 }
756 if (clockrt) {
757 microtime(&ctv);
758 timevalsub(&utv, &ctv);
759 } else if (args->op == LINUX_FUTEX_WAIT_BITSET) {
760 microuptime(&ctv);
761 timevalsub(&utv, &ctv);
762 }
763 if (utv.tv_sec < 0)
764 timevalclear(&utv);
765 timeout_hz = tvtohz(&utv);
766 } else
767 timeout_hz = 0;
768
769 error = futex_wait(f, wp, timeout_hz, args->val3);
770 break;
771
772 case LINUX_FUTEX_WAKE:
773 args->val3 = FUTEX_BITSET_MATCH_ANY;
774 /* FALLTHROUGH */
775
776 case LINUX_FUTEX_WAKE_BITSET:
777 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr,
778 args->val, args->val3);
779 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x",
780 args->uaddr, args->val, args->val3);
781
782 error = futex_get(args->uaddr, NULL, &f,
783 flags | FUTEX_DONTCREATE);
784 if (error) {
785 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
786 return (error);
787 }
788
789 if (f == NULL) {
790 td->td_retval[0] = 0;
791
792 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
793 return (error);
794 }
795 td->td_retval[0] = futex_wake(f, args->val, args->val3);
796 futex_put(f, NULL);
797 break;
798
799 case LINUX_FUTEX_CMP_REQUEUE:
800 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue,
801 args->uaddr, args->val, args->val3, args->uaddr2,
802 args->timeout);
803 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p "
804 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x",
805 args->uaddr, args->val, args->val3, args->uaddr2,
806 args->timeout);
807
808 /*
809 * Linux allows this, we would not, it is an incorrect
810 * usage of declared ABI, so return EINVAL.
811 */
812 if (args->uaddr == args->uaddr2) {
813 LIN_SDT_PROBE0(futex, linux_sys_futex,
814 invalid_cmp_requeue_use);
815 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
816 return (EINVAL);
817 }
818
819 error = futex_get(args->uaddr, NULL, &f, flags);
820 if (error) {
821 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
822 return (error);
823 }
824
825 /*
826 * To avoid deadlocks return EINVAL if second futex
827 * exists at this time.
828 *
829 * Glibc fall back to FUTEX_WAKE in case of any error
830 * returned by FUTEX_CMP_REQUEUE.
831 */
832 error = futex_get(args->uaddr2, NULL, &f2,
833 flags | FUTEX_DONTEXISTS);
834 if (error) {
835 futex_put(f, NULL);
836
837 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
838 return (error);
839 }
840 error = copyin(args->uaddr, &val, sizeof(val));
841 if (error) {
842 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error,
843 error);
844 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d",
845 error);
846 futex_put(f2, NULL);
847 futex_put(f, NULL);
848
849 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
850 return (error);
851 }
852 if (val != args->val3) {
853 LIN_SDT_PROBE2(futex, linux_sys_futex,
854 debug_cmp_requeue_value_neq, args->val, val);
855 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x",
856 args->val, val);
857 futex_put(f2, NULL);
858 futex_put(f, NULL);
859
860 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN);
861 return (EAGAIN);
862 }
863
864 nrwake = (int)(unsigned long)args->timeout;
865 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake);
866 futex_put(f2, NULL);
867 futex_put(f, NULL);
868 break;
869
870 case LINUX_FUTEX_WAKE_OP:
871 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op,
872 args->uaddr, args->op, args->val, args->uaddr2, args->val3);
873 LINUX_CTR5(sys_futex, "WAKE_OP "
874 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x",
875 args->uaddr, args->val, args->uaddr2, args->val3,
876 args->timeout);
877
878 error = futex_get(args->uaddr, NULL, &f, flags);
879 if (error) {
880 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
881 return (error);
882 }
883
884 if (args->uaddr != args->uaddr2)
885 error = futex_get(args->uaddr2, NULL, &f2, flags);
886 if (error) {
887 futex_put(f, NULL);
888
889 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
890 return (error);
891 }
892
893 /*
894 * This function returns positive number as results and
895 * negative as errors
896 */
897 op_ret = futex_atomic_op(td, args->val3, args->uaddr2);
898
899 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x",
900 args->uaddr, op_ret);
901
902 if (op_ret < 0) {
903 /* XXX: We don't handle the EFAULT yet. */
904 if (op_ret != -EFAULT) {
905 if (f2 != NULL)
906 futex_put(f2, NULL);
907 futex_put(f, NULL);
908
909 LIN_SDT_PROBE1(futex, linux_sys_futex, return,
910 -op_ret);
911 return (-op_ret);
912 } else {
913 LIN_SDT_PROBE0(futex, linux_sys_futex,
914 unhandled_efault);
915 }
916 if (f2 != NULL)
917 futex_put(f2, NULL);
918 futex_put(f, NULL);
919
920 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EFAULT);
921 return (EFAULT);
922 }
923
924 ret = futex_wake(f, args->val, args->val3);
925
926 if (op_ret > 0) {
927 op_ret = 0;
928 nrwake = (int)(unsigned long)args->timeout;
929
930 if (f2 != NULL)
931 op_ret += futex_wake(f2, nrwake, args->val3);
932 else
933 op_ret += futex_wake(f, nrwake, args->val3);
934 ret += op_ret;
935
936 }
937 if (f2 != NULL)
938 futex_put(f2, NULL);
939 futex_put(f, NULL);
940 td->td_retval[0] = ret;
941 break;
942
943 case LINUX_FUTEX_LOCK_PI:
944 /* not yet implemented */
945 linux_msg(td,
946 "linux_sys_futex: "
947 "op LINUX_FUTEX_LOCK_PI not implemented\n");
948 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_lock_pi);
949 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
950 return (ENOSYS);
951
952 case LINUX_FUTEX_UNLOCK_PI:
953 /* not yet implemented */
954 linux_msg(td,
955 "linux_sys_futex: "
956 "op LINUX_FUTEX_UNLOCK_PI not implemented\n");
957 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_unlock_pi);
958 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
959 return (ENOSYS);
960
961 case LINUX_FUTEX_TRYLOCK_PI:
962 /* not yet implemented */
963 linux_msg(td,
964 "linux_sys_futex: "
965 "op LINUX_FUTEX_TRYLOCK_PI not implemented\n");
966 LIN_SDT_PROBE0(futex, linux_sys_futex,
967 unimplemented_trylock_pi);
968 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
969 return (ENOSYS);
970
971 case LINUX_FUTEX_REQUEUE:
972
973 /*
974 * Glibc does not use this operation since version 2.3.3,
975 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation.
976 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when
977 * FUTEX_REQUEUE returned EINVAL.
978 */
979 em = em_find(td->td_proc, EMUL_DONTLOCK);
980 if ((em->flags & LINUX_XDEPR_REQUEUEOP) == 0) {
981 linux_msg(td,
982 "linux_sys_futex: "
983 "unsupported futex_requeue op\n");
984 em->flags |= LINUX_XDEPR_REQUEUEOP;
985 LIN_SDT_PROBE0(futex, linux_sys_futex,
986 deprecated_requeue);
987 }
988
989 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL);
990 return (EINVAL);
991
992 case LINUX_FUTEX_WAIT_REQUEUE_PI:
993 /* not yet implemented */
994 linux_msg(td,
995 "linux_sys_futex: "
996 "op FUTEX_WAIT_REQUEUE_PI not implemented\n");
997 LIN_SDT_PROBE0(futex, linux_sys_futex,
998 unimplemented_wait_requeue_pi);
999 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1000 return (ENOSYS);
1001
1002 case LINUX_FUTEX_CMP_REQUEUE_PI:
1003 /* not yet implemented */
1004 linux_msg(td,
1005 "linux_sys_futex: "
1006 "op LINUX_FUTEX_CMP_REQUEUE_PI not implemented\n");
1007 LIN_SDT_PROBE0(futex, linux_sys_futex,
1008 unimplemented_cmp_requeue_pi);
1009 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1010 return (ENOSYS);
1011
1012 default:
1013 linux_msg(td,
1014 "linux_sys_futex: unknown op %d\n", args->op);
1015 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation,
1016 args->op);
1017 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS);
1018 return (ENOSYS);
1019 }
1020
1021 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error);
1022 return (error);
1023 }
1024
1025 int
1026 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args)
1027 {
1028 struct linux_emuldata *em;
1029
1030 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args);
1031
1032 if (args->len != sizeof(struct linux_robust_list_head)) {
1033 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error);
1034 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL);
1035 return (EINVAL);
1036 }
1037
1038 em = em_find(td->td_proc, EMUL_DOLOCK);
1039 em->robust_futexes = args->head;
1040 EMUL_UNLOCK(&emul_lock);
1041
1042 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0);
1043 return (0);
1044 }
1045
1046 int
1047 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args)
1048 {
1049 struct linux_emuldata *em;
1050 struct linux_robust_list_head *head;
1051 l_size_t len = sizeof(struct linux_robust_list_head);
1052 int error = 0;
1053
1054 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args);
1055
1056 if (!args->pid) {
1057 em = em_find(td->td_proc, EMUL_DONTLOCK);
1058 head = em->robust_futexes;
1059 } else {
1060 struct proc *p;
1061
1062 p = pfind(args->pid);
1063 if (p == NULL) {
1064 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1065 ESRCH);
1066 return (ESRCH);
1067 }
1068
1069 em = em_find(p, EMUL_DONTLOCK);
1070 /* XXX: ptrace? */
1071 if (priv_check(td, PRIV_CRED_SETUID) ||
1072 priv_check(td, PRIV_CRED_SETEUID) ||
1073 p_candebug(td, p)) {
1074 PROC_UNLOCK(p);
1075
1076 LIN_SDT_PROBE1(futex, linux_get_robust_list, return,
1077 EPERM);
1078 return (EPERM);
1079 }
1080 head = em->robust_futexes;
1081
1082 PROC_UNLOCK(p);
1083 }
1084
1085 error = copyout(&len, args->len, sizeof(l_size_t));
1086 if (error) {
1087 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1088 error);
1089 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT);
1090 return (EFAULT);
1091 }
1092
1093 error = copyout(&head, args->head, sizeof(head));
1094 if (error) {
1095 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error,
1096 error);
1097 }
1098
1099 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error);
1100 return (error);
1101 }
1102
1103 static int
1104 handle_futex_death(struct proc *p, uint32_t *uaddr, int pi)
1105 {
1106 uint32_t uval, nval, mval;
1107 struct futex *f;
1108 int error;
1109
1110 LIN_SDT_PROBE3(futex, handle_futex_death, entry, p, uaddr, pi);
1111
1112 retry:
1113 error = copyin(uaddr, &uval, 4);
1114 if (error) {
1115 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error);
1116 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT);
1117 return (EFAULT);
1118 }
1119 if ((uval & FUTEX_TID_MASK) == p->p_pid) {
1120 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED;
1121 nval = casuword32(uaddr, uval, mval);
1122
1123 if (nval == -1) {
1124 LIN_SDT_PROBE1(futex, handle_futex_death, return,
1125 EFAULT);
1126 return (EFAULT);
1127 }
1128
1129 if (nval != uval)
1130 goto retry;
1131
1132 if (!pi && (uval & FUTEX_WAITERS)) {
1133 error = futex_get(uaddr, NULL, &f,
1134 FUTEX_DONTCREATE | FUTEX_SHARED);
1135 if (error) {
1136 LIN_SDT_PROBE1(futex, handle_futex_death,
1137 return, error);
1138 return (error);
1139 }
1140 if (f != NULL) {
1141 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY);
1142 futex_put(f, NULL);
1143 }
1144 }
1145 }
1146
1147 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0);
1148 return (0);
1149 }
1150
1151 static int
1152 fetch_robust_entry(struct linux_robust_list **entry,
1153 struct linux_robust_list **head, int *pi)
1154 {
1155 l_ulong uentry;
1156 int error;
1157
1158 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi);
1159
1160 error = copyin((const void *)head, &uentry, sizeof(l_ulong));
1161 if (error) {
1162 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error);
1163 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT);
1164 return (EFAULT);
1165 }
1166
1167 *entry = (void *)(uentry & ~1UL);
1168 *pi = uentry & 1;
1169
1170 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0);
1171 return (0);
1172 }
1173
1174 /* This walks the list of robust futexes releasing them. */
1175 void
1176 release_futexes(struct proc *p)
1177 {
1178 struct linux_robust_list_head *head = NULL;
1179 struct linux_robust_list *entry, *next_entry, *pending;
1180 unsigned int limit = 2048, pi, next_pi, pip;
1181 struct linux_emuldata *em;
1182 l_long futex_offset;
1183 int rc, error;
1184
1185 LIN_SDT_PROBE1(futex, release_futexes, entry, p);
1186
1187 em = em_find(p, EMUL_DONTLOCK);
1188 head = em->robust_futexes;
1189
1190 if (head == NULL) {
1191 LIN_SDT_PROBE0(futex, release_futexes, return);
1192 return;
1193 }
1194
1195 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) {
1196 LIN_SDT_PROBE0(futex, release_futexes, return);
1197 return;
1198 }
1199
1200 error = copyin(&head->futex_offset, &futex_offset,
1201 sizeof(futex_offset));
1202 if (error) {
1203 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error);
1204 LIN_SDT_PROBE0(futex, release_futexes, return);
1205 return;
1206 }
1207
1208 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) {
1209 LIN_SDT_PROBE0(futex, release_futexes, return);
1210 return;
1211 }
1212
1213 while (entry != &head->list) {
1214 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi);
1215
1216 if (entry != pending)
1217 if (handle_futex_death(p,
1218 (uint32_t *)((caddr_t)entry + futex_offset), pi)) {
1219 LIN_SDT_PROBE0(futex, release_futexes, return);
1220 return;
1221 }
1222 if (rc) {
1223 LIN_SDT_PROBE0(futex, release_futexes, return);
1224 return;
1225 }
1226
1227 entry = next_entry;
1228 pi = next_pi;
1229
1230 if (!--limit)
1231 break;
1232
1233 sched_relinquish(curthread);
1234 }
1235
1236 if (pending)
1237 handle_futex_death(p, (uint32_t *)((caddr_t)pending + futex_offset), pip);
1238
1239 LIN_SDT_PROBE0(futex, release_futexes, return);
1240 }
Cache object: 60d0ea0694b8aa99757240df5915c605
|