linux_futex.c revision 293896
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/9.3/sys/compat/linux/linux_futex.c 293896 2016-01-14 09:11:26Z 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 */ 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 **", "int", "uint32_t"); 133LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int"); 134LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int"); 135LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *", 136 "int", "uint32_t"); 137LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int", 138 "int"); 139LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check); 140LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int"); 141LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int"); 142LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int"); 143LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *", 144 "struct linux_sys_futex_args *"); 145LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch); 146LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, itimerfix_error, "int"); 147LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int"); 148LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use); 149LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *", 150 "uint32_t", "uint32_t"); 151LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq, 152 "uint32_t *", "uint32_t", "int", "uint32_t"); 153LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *", 154 "uint32_t", "uint32_t"); 155LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *", 156 "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *"); 157LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq, 158 "uint32_t", "int"); 159LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *", 160 "int", "uint32_t", "uint32_t *", "uint32_t"); 161LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault); 162LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi); 163LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi); 164LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi); 165LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue); 166LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi); 167LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi); 168LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int"); 169LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int"); 170LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *", 171 "struct linux_set_robust_list_args *"); 172LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error); 173LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int"); 174LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *", 175 "struct linux_get_robust_list_args *"); 176LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int"); 177LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int"); 178LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry, "struct proc *", 179 "uint32_t *", "int"); 180LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int"); 181LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int"); 182LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry, 183 "struct linux_robust_list **", "struct linux_robust_list **", "int *"); 184LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int"); 185LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int"); 186LIN_SDT_PROBE_DEFINE1(futex, release_futexes, entry, "struct proc *"); 187LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int"); 188LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return); 189 190static MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes"); 191static MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futexes wp"); 192 193struct futex; 194 195struct waiting_proc { 196 uint32_t wp_flags; 197 struct futex *wp_futex; 198 TAILQ_ENTRY(waiting_proc) wp_list; 199}; 200 201struct 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 211struct 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 228struct 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 */ 256int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval); 257int futex_addl(int oparg, uint32_t *uaddr, int *oldval); 258int futex_orl(int oparg, uint32_t *uaddr, int *oldval); 259int futex_andl(int oparg, uint32_t *uaddr, int *oldval); 260int futex_xorl(int oparg, uint32_t *uaddr, int *oldval); 261 262static void 263futex_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 302static int 303futex_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 } 320retry: 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 399static int 400futex_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 430static int 431futex_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 471static int 472futex_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 509static int 510futex_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 556static int 557futex_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 580static int 581futex_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 655int 656linux_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 1025int 1026linux_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 1046int 1047linux_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 1103static int 1104handle_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 1112retry: 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 1151static int 1152fetch_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. */ 1175void 1176release_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} 1241