linux_futex.c revision 266918
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: stable/10/sys/compat/linux/linux_futex.c 266918 2014-05-31 05:59:55Z 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 */ 72LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE); 73 74/* Linuxulator-global DTrace probes */ 75LIN_SDT_PROBE_DECLARE(locks, emul_lock, locked); 76LIN_SDT_PROBE_DECLARE(locks, emul_lock, unlock); 77 78/** 79 * Futex part for the special DTrace module "locks". 80 */ 81LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *"); 82LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *"); 83 84/** 85 * Per futex probes. 86 */ 87LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *"); 88LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *"); 89 90/** 91 * DTrace probes in this module. 92 */ 93LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *", 94 "struct waiting_proc *"); 95LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t", 96 "int"); 97LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t", 98 "int"); 99LIN_SDT_PROBE_DEFINE0(futex, futex_put, return); 100LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **", 101 "uint32_t"); 102LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int"); 103LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t", 104 "int"); 105LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *"); 106LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int"); 107LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int"); 108LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *", 109 "struct waiting_proc **", "struct futex **"); 110LIN_SDT_PROBE_DEFINE0(futex, futex_get, error); 111LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int"); 112LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *", 113 "struct waiting_proc **", "int"); 114LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *", 115 "struct waiting_proc *", "uint32_t *", "uint32_t"); 116LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *", 117 "struct waiting_proc *"); 118LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int"); 119LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int", 120 "uint32_t"); 121LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t", 122 "struct waiting_proc *", "uint32_t"); 123LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *"); 124LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int"); 125LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int", 126 "struct futex *", "int"); 127LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *"); 128LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *", 129 "struct waiting_proc *", "uint32_t"); 130LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int"); 131LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *", 132 "struct waiting_proc **", "struct l_timespec *", "uint32_t"); 133LIN_SDT_PROBE_DEFINE1(futex, futex_wait, copyin_error, "int"); 134LIN_SDT_PROBE_DEFINE1(futex, futex_wait, itimerfix_error, "int"); 135LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int"); 136LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int"); 137LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *", 138 "int", "uint32_t"); 139LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int", 140 "int"); 141LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check); 142LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int"); 143LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int"); 144LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int"); 145LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *", 146 "struct linux_sys_futex_args *"); 147LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch); 148LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int"); 149LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use); 150LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *", 151 "uint32_t", "uint32_t"); 152LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq, 153 "uint32_t *", "uint32_t", "int", "uint32_t"); 154LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *", 155 "uint32_t", "uint32_t"); 156LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *", 157 "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *"); 158LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq, 159 "uint32_t", "int"); 160LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *", 161 "int", "uint32_t", "uint32_t *", "uint32_t"); 162LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault); 163LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi); 164LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi); 165LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi); 166LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue); 167LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi); 168LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi); 169LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int"); 170LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int"); 171LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *", 172 "struct linux_set_robust_list_args *"); 173LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error); 174LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int"); 175LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *", 176 "struct linux_get_robust_list_args *"); 177LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int"); 178LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int"); 179LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry, "struct proc *", 180 "uint32_t *", "int"); 181LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int"); 182LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int"); 183LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry, 184 "struct linux_robust_list **", "struct linux_robust_list **", "int *"); 185LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int"); 186LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int"); 187LIN_SDT_PROBE_DEFINE1(futex, release_futexes, entry, "struct proc *"); 188LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int"); 189LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return); 190 191static MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes"); 192static MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futexes wp"); 193 194struct futex; 195 196struct waiting_proc { 197 uint32_t wp_flags; 198 struct futex *wp_futex; 199 TAILQ_ENTRY(waiting_proc) wp_list; 200}; 201 202struct 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 212struct 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 229struct 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 */ 257int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval); 258int futex_addl(int oparg, uint32_t *uaddr, int *oldval); 259int futex_orl(int oparg, uint32_t *uaddr, int *oldval); 260int futex_andl(int oparg, uint32_t *uaddr, int *oldval); 261int futex_xorl(int oparg, uint32_t *uaddr, int *oldval); 262 263static void 264futex_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 303static int 304futex_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 } 321retry: 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 400static int 401futex_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 431static int 432futex_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 472static int 473futex_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 510static int 511futex_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 557static int 558futex_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 605static int 606futex_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 680int 681linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) 682{ 683 int clockrt, nrwake, op_ret, ret; 684 struct linux_emuldata *em; 685 struct waiting_proc *wp; 686 struct futex *f, *f2; 687 int error; 688 uint32_t flags, val; 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 0x%x bitset 0x%x", 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_CTR3(sys_futex, 751 "WAIT uaddr %p val 0x%x != uval 0x%x", 752 args->uaddr, args->val, val); 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 nrwake 0x%x bitset 0x%x", 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 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x", 796 args->uaddr, args->val, args->val3, args->uaddr2, 797 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 0x%x != uval 0x%x", 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 nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x", 866 args->uaddr, args->val, args->uaddr2, args->val3, 867 args->timeout); 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 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x", 891 args->uaddr, op_ret); 892 893 if (op_ret < 0) { 894 /* XXX: We don't handle the EFAULT yet. */ 895 if (op_ret != -EFAULT) { 896 if (f2 != NULL) 897 futex_put(f2, NULL); 898 futex_put(f, NULL); 899 900 LIN_SDT_PROBE1(futex, linux_sys_futex, return, 901 -op_ret); 902 return (-op_ret); 903 } else { 904 LIN_SDT_PROBE0(futex, linux_sys_futex, 905 unhandled_efault); 906 } 907 if (f2 != NULL) 908 futex_put(f2, NULL); 909 futex_put(f, NULL); 910 911 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EFAULT); 912 return (EFAULT); 913 } 914 915 ret = futex_wake(f, args->val, args->val3); 916 917 if (op_ret > 0) { 918 op_ret = 0; 919 nrwake = (int)(unsigned long)args->timeout; 920 921 if (f2 != NULL) 922 op_ret += futex_wake(f2, nrwake, args->val3); 923 else 924 op_ret += futex_wake(f, nrwake, args->val3); 925 ret += op_ret; 926 927 } 928 if (f2 != NULL) 929 futex_put(f2, NULL); 930 futex_put(f, NULL); 931 td->td_retval[0] = ret; 932 break; 933 934 case LINUX_FUTEX_LOCK_PI: 935 /* not yet implemented */ 936 linux_msg(td, 937 "linux_sys_futex: " 938 "op LINUX_FUTEX_LOCK_PI not implemented\n"); 939 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_lock_pi); 940 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 941 return (ENOSYS); 942 943 case LINUX_FUTEX_UNLOCK_PI: 944 /* not yet implemented */ 945 linux_msg(td, 946 "linux_sys_futex: " 947 "op LINUX_FUTEX_UNLOCK_PI not implemented\n"); 948 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_unlock_pi); 949 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 950 return (ENOSYS); 951 952 case LINUX_FUTEX_TRYLOCK_PI: 953 /* not yet implemented */ 954 linux_msg(td, 955 "linux_sys_futex: " 956 "op LINUX_FUTEX_TRYLOCK_PI not implemented\n"); 957 LIN_SDT_PROBE0(futex, linux_sys_futex, 958 unimplemented_trylock_pi); 959 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 960 return (ENOSYS); 961 962 case LINUX_FUTEX_REQUEUE: 963 964 /* 965 * Glibc does not use this operation since version 2.3.3, 966 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. 967 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when 968 * FUTEX_REQUEUE returned EINVAL. 969 */ 970 em = em_find(td->td_proc, EMUL_DONTLOCK); 971 if ((em->flags & LINUX_XDEPR_REQUEUEOP) == 0) { 972 linux_msg(td, 973 "linux_sys_futex: " 974 "unsupported futex_requeue op\n"); 975 em->flags |= LINUX_XDEPR_REQUEUEOP; 976 LIN_SDT_PROBE0(futex, linux_sys_futex, 977 deprecated_requeue); 978 } 979 980 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 981 return (EINVAL); 982 983 case LINUX_FUTEX_WAIT_REQUEUE_PI: 984 /* not yet implemented */ 985 linux_msg(td, 986 "linux_sys_futex: " 987 "op FUTEX_WAIT_REQUEUE_PI not implemented\n"); 988 LIN_SDT_PROBE0(futex, linux_sys_futex, 989 unimplemented_wait_requeue_pi); 990 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 991 return (ENOSYS); 992 993 case LINUX_FUTEX_CMP_REQUEUE_PI: 994 /* not yet implemented */ 995 linux_msg(td, 996 "linux_sys_futex: " 997 "op LINUX_FUTEX_CMP_REQUEUE_PI not implemented\n"); 998 LIN_SDT_PROBE0(futex, linux_sys_futex, 999 unimplemented_cmp_requeue_pi); 1000 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1001 return (ENOSYS); 1002 1003 default: 1004 linux_msg(td, 1005 "linux_sys_futex: unknown op %d\n", args->op); 1006 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation, 1007 args->op); 1008 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1009 return (ENOSYS); 1010 } 1011 1012 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 1013 return (error); 1014} 1015 1016int 1017linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) 1018{ 1019 struct linux_emuldata *em; 1020 1021 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args); 1022 1023 if (args->len != sizeof(struct linux_robust_list_head)) { 1024 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error); 1025 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL); 1026 return (EINVAL); 1027 } 1028 1029 em = em_find(td->td_proc, EMUL_DOLOCK); 1030 em->robust_futexes = args->head; 1031 EMUL_UNLOCK(&emul_lock); 1032 1033 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0); 1034 return (0); 1035} 1036 1037int 1038linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args) 1039{ 1040 struct linux_emuldata *em; 1041 struct linux_robust_list_head *head; 1042 l_size_t len = sizeof(struct linux_robust_list_head); 1043 int error = 0; 1044 1045 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args); 1046 1047 if (!args->pid) { 1048 em = em_find(td->td_proc, EMUL_DONTLOCK); 1049 head = em->robust_futexes; 1050 } else { 1051 struct proc *p; 1052 1053 p = pfind(args->pid); 1054 if (p == NULL) { 1055 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1056 ESRCH); 1057 return (ESRCH); 1058 } 1059 1060 em = em_find(p, EMUL_DONTLOCK); 1061 /* XXX: ptrace? */ 1062 if (priv_check(td, PRIV_CRED_SETUID) || 1063 priv_check(td, PRIV_CRED_SETEUID) || 1064 p_candebug(td, p)) { 1065 PROC_UNLOCK(p); 1066 1067 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1068 EPERM); 1069 return (EPERM); 1070 } 1071 head = em->robust_futexes; 1072 1073 PROC_UNLOCK(p); 1074 } 1075 1076 error = copyout(&len, args->len, sizeof(l_size_t)); 1077 if (error) { 1078 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1079 error); 1080 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT); 1081 return (EFAULT); 1082 } 1083 1084 error = copyout(head, args->head, sizeof(struct linux_robust_list_head)); 1085 if (error) { 1086 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1087 error); 1088 } 1089 1090 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error); 1091 return (error); 1092} 1093 1094static int 1095handle_futex_death(struct proc *p, uint32_t *uaddr, int pi) 1096{ 1097 uint32_t uval, nval, mval; 1098 struct futex *f; 1099 int error; 1100 1101 LIN_SDT_PROBE3(futex, handle_futex_death, entry, p, uaddr, pi); 1102 1103retry: 1104 error = copyin(uaddr, &uval, 4); 1105 if (error) { 1106 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error); 1107 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT); 1108 return (EFAULT); 1109 } 1110 if ((uval & FUTEX_TID_MASK) == p->p_pid) { 1111 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; 1112 nval = casuword32(uaddr, uval, mval); 1113 1114 if (nval == -1) { 1115 LIN_SDT_PROBE1(futex, handle_futex_death, return, 1116 EFAULT); 1117 return (EFAULT); 1118 } 1119 1120 if (nval != uval) 1121 goto retry; 1122 1123 if (!pi && (uval & FUTEX_WAITERS)) { 1124 error = futex_get(uaddr, NULL, &f, 1125 FUTEX_DONTCREATE | FUTEX_SHARED); 1126 if (error) { 1127 LIN_SDT_PROBE1(futex, handle_futex_death, 1128 return, error); 1129 return (error); 1130 } 1131 if (f != NULL) { 1132 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY); 1133 futex_put(f, NULL); 1134 } 1135 } 1136 } 1137 1138 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0); 1139 return (0); 1140} 1141 1142static int 1143fetch_robust_entry(struct linux_robust_list **entry, 1144 struct linux_robust_list **head, int *pi) 1145{ 1146 l_ulong uentry; 1147 int error; 1148 1149 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi); 1150 1151 error = copyin((const void *)head, &uentry, sizeof(l_ulong)); 1152 if (error) { 1153 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error); 1154 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT); 1155 return (EFAULT); 1156 } 1157 1158 *entry = (void *)(uentry & ~1UL); 1159 *pi = uentry & 1; 1160 1161 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0); 1162 return (0); 1163} 1164 1165/* This walks the list of robust futexes releasing them. */ 1166void 1167release_futexes(struct proc *p) 1168{ 1169 struct linux_robust_list_head *head = NULL; 1170 struct linux_robust_list *entry, *next_entry, *pending; 1171 unsigned int limit = 2048, pi, next_pi, pip; 1172 struct linux_emuldata *em; 1173 l_long futex_offset; 1174 int rc, error; 1175 1176 LIN_SDT_PROBE1(futex, release_futexes, entry, p); 1177 1178 em = em_find(p, EMUL_DONTLOCK); 1179 head = em->robust_futexes; 1180 1181 if (head == NULL) { 1182 LIN_SDT_PROBE0(futex, release_futexes, return); 1183 return; 1184 } 1185 1186 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) { 1187 LIN_SDT_PROBE0(futex, release_futexes, return); 1188 return; 1189 } 1190 1191 error = copyin(&head->futex_offset, &futex_offset, 1192 sizeof(futex_offset)); 1193 if (error) { 1194 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error); 1195 LIN_SDT_PROBE0(futex, release_futexes, return); 1196 return; 1197 } 1198 1199 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) { 1200 LIN_SDT_PROBE0(futex, release_futexes, return); 1201 return; 1202 } 1203 1204 while (entry != &head->list) { 1205 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); 1206 1207 if (entry != pending) 1208 if (handle_futex_death(p, 1209 (uint32_t *)((caddr_t)entry + futex_offset), pi)) { 1210 LIN_SDT_PROBE0(futex, release_futexes, return); 1211 return; 1212 } 1213 if (rc) { 1214 LIN_SDT_PROBE0(futex, release_futexes, return); 1215 return; 1216 } 1217 1218 entry = next_entry; 1219 pi = next_pi; 1220 1221 if (!--limit) 1222 break; 1223 1224 sched_relinquish(curthread); 1225 } 1226 1227 if (pending) 1228 handle_futex_death(p, (uint32_t *)((caddr_t)pending + futex_offset), pip); 1229 1230 LIN_SDT_PROBE0(futex, release_futexes, return); 1231} 1232