linux_futex.c revision 293564
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 293564 2016-01-09 17:10:22Z 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/** 75 * Futex part for the special DTrace module "locks". 76 */ 77LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *"); 78LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *"); 79 80/** 81 * Per futex probes. 82 */ 83LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *"); 84LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *"); 85 86/** 87 * DTrace probes in this module. 88 */ 89LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *", 90 "struct waiting_proc *"); 91LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t", 92 "int"); 93LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t", 94 "int"); 95LIN_SDT_PROBE_DEFINE0(futex, futex_put, return); 96LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **", 97 "uint32_t"); 98LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int"); 99LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t", 100 "int"); 101LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *"); 102LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int"); 103LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int"); 104LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *", 105 "struct waiting_proc **", "struct futex **"); 106LIN_SDT_PROBE_DEFINE0(futex, futex_get, error); 107LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int"); 108LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *", 109 "struct waiting_proc **", "int"); 110LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *", 111 "struct waiting_proc *", "uint32_t *", "uint32_t"); 112LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *", 113 "struct waiting_proc *"); 114LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int"); 115LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int", 116 "uint32_t"); 117LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t", 118 "struct waiting_proc *", "uint32_t"); 119LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *"); 120LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int"); 121LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int", 122 "struct futex *", "int"); 123LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *"); 124LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *", 125 "struct waiting_proc *", "uint32_t"); 126LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int"); 127LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *", 128 "struct waiting_proc **", "int", "uint32_t"); 129LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int"); 130LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int"); 131LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *", 132 "int", "uint32_t"); 133LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int", 134 "int"); 135LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check); 136LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int"); 137LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int"); 138LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int"); 139LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *", 140 "struct linux_sys_futex_args *"); 141LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch); 142LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, itimerfix_error, "int"); 143LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int"); 144LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use); 145LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *", 146 "uint32_t", "uint32_t"); 147LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq, 148 "uint32_t *", "uint32_t", "int", "uint32_t"); 149LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *", 150 "uint32_t", "uint32_t"); 151LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *", 152 "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *"); 153LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq, 154 "uint32_t", "int"); 155LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *", 156 "int", "uint32_t", "uint32_t *", "uint32_t"); 157LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault); 158LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi); 159LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi); 160LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi); 161LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue); 162LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi); 163LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi); 164LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int"); 165LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int"); 166LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *", 167 "struct linux_set_robust_list_args *"); 168LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error); 169LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int"); 170LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *", 171 "struct linux_get_robust_list_args *"); 172LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int"); 173LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int"); 174LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry, 175 "struct linux_emuldata *", "uint32_t *", "unsigned int"); 176LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int"); 177LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int"); 178LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry, 179 "struct linux_robust_list **", "struct linux_robust_list **", 180 "unsigned int *"); 181LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int"); 182LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int"); 183LIN_SDT_PROBE_DEFINE2(futex, release_futexes, entry, "struct thread *", 184 "struct linux_emuldata *"); 185LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int"); 186LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return); 187 188struct futex; 189 190struct waiting_proc { 191 uint32_t wp_flags; 192 struct futex *wp_futex; 193 TAILQ_ENTRY(waiting_proc) wp_list; 194}; 195 196struct futex { 197 struct sx f_lck; 198 uint32_t *f_uaddr; /* user-supplied value, for debug */ 199 struct umtx_key f_key; 200 uint32_t f_refcount; 201 uint32_t f_bitset; 202 LIST_ENTRY(futex) f_list; 203 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc; 204}; 205 206struct futex_list futex_list; 207 208#define FUTEX_LOCK(f) sx_xlock(&(f)->f_lck) 209#define FUTEX_UNLOCK(f) sx_xunlock(&(f)->f_lck) 210#define FUTEX_INIT(f) do { \ 211 sx_init_flags(&(f)->f_lck, "ftlk", \ 212 SX_DUPOK); \ 213 LIN_SDT_PROBE1(futex, futex, create, \ 214 &(f)->f_lck); \ 215 } while (0) 216#define FUTEX_DESTROY(f) do { \ 217 LIN_SDT_PROBE1(futex, futex, destroy, \ 218 &(f)->f_lck); \ 219 sx_destroy(&(f)->f_lck); \ 220 } while (0) 221#define FUTEX_ASSERT_LOCKED(f) sx_assert(&(f)->f_lck, SA_XLOCKED) 222 223struct mtx futex_mtx; /* protects the futex list */ 224#define FUTEXES_LOCK do { \ 225 mtx_lock(&futex_mtx); \ 226 LIN_SDT_PROBE1(locks, futex_mtx, \ 227 locked, &futex_mtx); \ 228 } while (0) 229#define FUTEXES_UNLOCK do { \ 230 LIN_SDT_PROBE1(locks, futex_mtx, \ 231 unlock, &futex_mtx); \ 232 mtx_unlock(&futex_mtx); \ 233 } while (0) 234 235/* flags for futex_get() */ 236#define FUTEX_CREATE_WP 0x1 /* create waiting_proc */ 237#define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */ 238#define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */ 239#define FUTEX_SHARED 0x8 /* shared futex */ 240 241/* wp_flags */ 242#define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list 243 * of futex where thread sleep to wp_list 244 * of another futex. 245 */ 246#define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex 247 * wp_list to prevent double wakeup. 248 */ 249 250static void futex_put(struct futex *, struct waiting_proc *); 251static int futex_get0(uint32_t *, struct futex **f, uint32_t); 252static int futex_get(uint32_t *, struct waiting_proc **, struct futex **, 253 uint32_t); 254static int futex_sleep(struct futex *, struct waiting_proc *, int); 255static int futex_wake(struct futex *, int, uint32_t); 256static int futex_requeue(struct futex *, int, struct futex *, int); 257static int futex_wait(struct futex *, struct waiting_proc *, int, 258 uint32_t); 259static int futex_atomic_op(struct thread *, int, uint32_t *); 260static int handle_futex_death(struct linux_emuldata *, uint32_t *, 261 unsigned int); 262static int fetch_robust_entry(struct linux_robust_list **, 263 struct linux_robust_list **, unsigned int *); 264 265/* support.s */ 266int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval); 267int futex_addl(int oparg, uint32_t *uaddr, int *oldval); 268int futex_orl(int oparg, uint32_t *uaddr, int *oldval); 269int futex_andl(int oparg, uint32_t *uaddr, int *oldval); 270int futex_xorl(int oparg, uint32_t *uaddr, int *oldval); 271 272 273static void 274futex_put(struct futex *f, struct waiting_proc *wp) 275{ 276 LIN_SDT_PROBE2(futex, futex_put, entry, f, wp); 277 278 FUTEX_ASSERT_LOCKED(f); 279 if (wp != NULL) { 280 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0) 281 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 282 free(wp, M_FUTEX_WP); 283 } 284 285 FUTEXES_LOCK; 286 if (--f->f_refcount == 0) { 287 LIST_REMOVE(f, f_list); 288 FUTEXES_UNLOCK; 289 FUTEX_UNLOCK(f); 290 291 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr, 292 f->f_refcount, f->f_key.shared); 293 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d " 294 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared); 295 umtx_key_release(&f->f_key); 296 FUTEX_DESTROY(f); 297 free(f, M_FUTEX); 298 299 LIN_SDT_PROBE0(futex, futex_put, return); 300 return; 301 } 302 303 LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount, 304 f->f_key.shared); 305 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d", 306 f->f_uaddr, f->f_refcount, f->f_key.shared); 307 FUTEXES_UNLOCK; 308 FUTEX_UNLOCK(f); 309 310 LIN_SDT_PROBE0(futex, futex_put, return); 311} 312 313static int 314futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags) 315{ 316 struct futex *f, *tmpf; 317 struct umtx_key key; 318 int error; 319 320 LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags); 321 322 *newf = tmpf = NULL; 323 324 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ? 325 AUTO_SHARE : THREAD_SHARE, &key); 326 if (error) { 327 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error); 328 LIN_SDT_PROBE1(futex, futex_get0, return, error); 329 return (error); 330 } 331retry: 332 FUTEXES_LOCK; 333 LIST_FOREACH(f, &futex_list, f_list) { 334 if (umtx_key_match(&f->f_key, &key)) { 335 if (tmpf != NULL) { 336 FUTEX_UNLOCK(tmpf); 337 FUTEX_DESTROY(tmpf); 338 free(tmpf, M_FUTEX); 339 } 340 if (flags & FUTEX_DONTEXISTS) { 341 FUTEXES_UNLOCK; 342 umtx_key_release(&key); 343 344 LIN_SDT_PROBE1(futex, futex_get0, return, 345 EINVAL); 346 return (EINVAL); 347 } 348 349 /* 350 * Increment refcount of the found futex to 351 * prevent it from deallocation before FUTEX_LOCK() 352 */ 353 ++f->f_refcount; 354 FUTEXES_UNLOCK; 355 umtx_key_release(&key); 356 357 FUTEX_LOCK(f); 358 *newf = f; 359 LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr, 360 f->f_refcount, f->f_key.shared); 361 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d", 362 uaddr, f->f_refcount, f->f_key.shared); 363 364 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 365 return (0); 366 } 367 } 368 369 if (flags & FUTEX_DONTCREATE) { 370 FUTEXES_UNLOCK; 371 umtx_key_release(&key); 372 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr); 373 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr); 374 375 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 376 return (0); 377 } 378 379 if (tmpf == NULL) { 380 FUTEXES_UNLOCK; 381 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO); 382 tmpf->f_uaddr = uaddr; 383 tmpf->f_key = key; 384 tmpf->f_refcount = 1; 385 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY; 386 FUTEX_INIT(tmpf); 387 TAILQ_INIT(&tmpf->f_waiting_proc); 388 389 /* 390 * Lock the new futex before an insert into the futex_list 391 * to prevent futex usage by other. 392 */ 393 FUTEX_LOCK(tmpf); 394 goto retry; 395 } 396 397 LIST_INSERT_HEAD(&futex_list, tmpf, f_list); 398 FUTEXES_UNLOCK; 399 400 LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount, 401 tmpf->f_key.shared); 402 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new", 403 uaddr, tmpf->f_refcount, tmpf->f_key.shared); 404 *newf = tmpf; 405 406 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 407 return (0); 408} 409 410static int 411futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f, 412 uint32_t flags) 413{ 414 int error; 415 416 LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f); 417 418 if (flags & FUTEX_CREATE_WP) { 419 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK); 420 (*wp)->wp_flags = 0; 421 } 422 error = futex_get0(uaddr, f, flags); 423 if (error) { 424 LIN_SDT_PROBE0(futex, futex_get, error); 425 426 if (flags & FUTEX_CREATE_WP) 427 free(*wp, M_FUTEX_WP); 428 429 LIN_SDT_PROBE1(futex, futex_get, return, error); 430 return (error); 431 } 432 if (flags & FUTEX_CREATE_WP) { 433 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list); 434 (*wp)->wp_futex = *f; 435 } 436 437 LIN_SDT_PROBE1(futex, futex_get, return, error); 438 return (error); 439} 440 441static int 442futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout) 443{ 444 int error; 445 446 FUTEX_ASSERT_LOCKED(f); 447 LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, timeout); 448 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d", 449 f->f_uaddr, wp, timeout, f->f_refcount); 450 error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout); 451 if (wp->wp_flags & FUTEX_WP_REQUEUED) { 452 KASSERT(f != wp->wp_futex, ("futex != wp_futex")); 453 454 if (error) { 455 LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error, 456 f->f_uaddr, wp, wp->wp_futex->f_uaddr, 457 wp->wp_futex->f_refcount); 458 } 459 460 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp" 461 " %p requeued uaddr %p ref %d", 462 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr, 463 wp->wp_futex->f_refcount); 464 futex_put(f, NULL); 465 f = wp->wp_futex; 466 FUTEX_LOCK(f); 467 } else { 468 if (error) { 469 LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error, 470 f->f_uaddr, wp); 471 } 472 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p", 473 error, f->f_uaddr, wp); 474 } 475 476 futex_put(f, wp); 477 478 LIN_SDT_PROBE1(futex, futex_sleep, return, error); 479 return (error); 480} 481 482static int 483futex_wake(struct futex *f, int n, uint32_t bitset) 484{ 485 struct waiting_proc *wp, *wpt; 486 int count = 0; 487 488 LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset); 489 490 if (bitset == 0) { 491 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL); 492 return (EINVAL); 493 } 494 495 FUTEX_ASSERT_LOCKED(f); 496 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 497 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp, 498 f->f_refcount); 499 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d", 500 f->f_uaddr, wp, f->f_refcount); 501 /* 502 * Unless we find a matching bit in 503 * the bitset, continue searching. 504 */ 505 if (!(wp->wp_futex->f_bitset & bitset)) 506 continue; 507 508 wp->wp_flags |= FUTEX_WP_REMOVED; 509 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 510 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp); 511 wakeup_one(wp); 512 if (++count == n) 513 break; 514 } 515 516 LIN_SDT_PROBE1(futex, futex_wake, return, count); 517 return (count); 518} 519 520static int 521futex_requeue(struct futex *f, int n, struct futex *f2, int n2) 522{ 523 struct waiting_proc *wp, *wpt; 524 int count = 0; 525 526 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2); 527 528 FUTEX_ASSERT_LOCKED(f); 529 FUTEX_ASSERT_LOCKED(f2); 530 531 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 532 if (++count <= n) { 533 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p", 534 f->f_uaddr, wp); 535 wp->wp_flags |= FUTEX_WP_REMOVED; 536 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 537 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp); 538 wakeup_one(wp); 539 } else { 540 LIN_SDT_PROBE3(futex, futex_requeue, requeue, 541 f->f_uaddr, wp, f2->f_uaddr); 542 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p", 543 f->f_uaddr, wp, f2->f_uaddr); 544 wp->wp_flags |= FUTEX_WP_REQUEUED; 545 /* Move wp to wp_list of f2 futex */ 546 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 547 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list); 548 549 /* 550 * Thread which sleeps on wp after waking should 551 * acquire f2 lock, so increment refcount of f2 to 552 * prevent it from premature deallocation. 553 */ 554 wp->wp_futex = f2; 555 FUTEXES_LOCK; 556 ++f2->f_refcount; 557 FUTEXES_UNLOCK; 558 if (count - n >= n2) 559 break; 560 } 561 } 562 563 LIN_SDT_PROBE1(futex, futex_requeue, return, count); 564 return (count); 565} 566 567static int 568futex_wait(struct futex *f, struct waiting_proc *wp, int timeout_hz, 569 uint32_t bitset) 570{ 571 int error; 572 573 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, timeout_hz, bitset); 574 575 if (bitset == 0) { 576 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL); 577 return (EINVAL); 578 } 579 580 f->f_bitset = bitset; 581 error = futex_sleep(f, wp, timeout_hz); 582 if (error) 583 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error); 584 if (error == EWOULDBLOCK) 585 error = ETIMEDOUT; 586 587 LIN_SDT_PROBE1(futex, futex_wait, return, error); 588 return (error); 589} 590 591static int 592futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr) 593{ 594 int op = (encoded_op >> 28) & 7; 595 int cmp = (encoded_op >> 24) & 15; 596 int oparg = (encoded_op << 8) >> 20; 597 int cmparg = (encoded_op << 20) >> 20; 598 int oldval = 0, ret; 599 600 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr); 601 602 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 603 oparg = 1 << oparg; 604 605 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg, 606 cmparg); 607 608 /* XXX: Linux verifies access here and returns EFAULT */ 609 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check); 610 611 switch (op) { 612 case FUTEX_OP_SET: 613 ret = futex_xchgl(oparg, uaddr, &oldval); 614 break; 615 case FUTEX_OP_ADD: 616 ret = futex_addl(oparg, uaddr, &oldval); 617 break; 618 case FUTEX_OP_OR: 619 ret = futex_orl(oparg, uaddr, &oldval); 620 break; 621 case FUTEX_OP_ANDN: 622 ret = futex_andl(~oparg, uaddr, &oldval); 623 break; 624 case FUTEX_OP_XOR: 625 ret = futex_xorl(oparg, uaddr, &oldval); 626 break; 627 default: 628 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op); 629 ret = -ENOSYS; 630 break; 631 } 632 633 if (ret) { 634 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 635 return (ret); 636 } 637 638 switch (cmp) { 639 case FUTEX_OP_CMP_EQ: 640 ret = (oldval == cmparg); 641 break; 642 case FUTEX_OP_CMP_NE: 643 ret = (oldval != cmparg); 644 break; 645 case FUTEX_OP_CMP_LT: 646 ret = (oldval < cmparg); 647 break; 648 case FUTEX_OP_CMP_GE: 649 ret = (oldval >= cmparg); 650 break; 651 case FUTEX_OP_CMP_LE: 652 ret = (oldval <= cmparg); 653 break; 654 case FUTEX_OP_CMP_GT: 655 ret = (oldval > cmparg); 656 break; 657 default: 658 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp); 659 ret = -ENOSYS; 660 } 661 662 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 663 return (ret); 664} 665 666int 667linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) 668{ 669 int clockrt, nrwake, op_ret, ret; 670 struct linux_pemuldata *pem; 671 struct waiting_proc *wp; 672 struct futex *f, *f2; 673 struct l_timespec timeout; 674 struct timeval utv, ctv; 675 int timeout_hz; 676 int error; 677 uint32_t flags, val; 678 679 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args); 680 681 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { 682 flags = 0; 683 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG; 684 } else 685 flags = FUTEX_SHARED; 686 687 /* 688 * Currently support for switching between CLOCK_MONOTONIC and 689 * CLOCK_REALTIME is not present. However Linux forbids the use of 690 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and 691 * FUTEX_WAIT_REQUEUE_PI. 692 */ 693 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME; 694 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME; 695 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET && 696 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) { 697 LIN_SDT_PROBE0(futex, linux_sys_futex, 698 unimplemented_clockswitch); 699 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 700 return (ENOSYS); 701 } 702 703 error = 0; 704 f = f2 = NULL; 705 706 switch (args->op) { 707 case LINUX_FUTEX_WAIT: 708 args->val3 = FUTEX_BITSET_MATCH_ANY; 709 /* FALLTHROUGH */ 710 711 case LINUX_FUTEX_WAIT_BITSET: 712 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr, 713 args->val, args->val3); 714 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x", 715 args->uaddr, args->val, args->val3); 716 717 error = futex_get(args->uaddr, &wp, &f, 718 flags | FUTEX_CREATE_WP); 719 if (error) { 720 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 721 return (error); 722 } 723 724 error = copyin(args->uaddr, &val, sizeof(val)); 725 if (error) { 726 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 727 error); 728 LINUX_CTR1(sys_futex, "WAIT copyin failed %d", 729 error); 730 futex_put(f, wp); 731 732 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 733 return (error); 734 } 735 if (val != args->val) { 736 LIN_SDT_PROBE4(futex, linux_sys_futex, 737 debug_wait_value_neq, args->uaddr, args->val, val, 738 args->val3); 739 LINUX_CTR3(sys_futex, 740 "WAIT uaddr %p val 0x%x != uval 0x%x", 741 args->uaddr, args->val, val); 742 futex_put(f, wp); 743 744 LIN_SDT_PROBE1(futex, linux_sys_futex, return, 745 EWOULDBLOCK); 746 return (EWOULDBLOCK); 747 } 748 749 if (args->timeout != NULL) { 750 error = copyin(args->timeout, &timeout, sizeof(timeout)); 751 if (error) { 752 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 753 error); 754 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 755 futex_put(f, wp); 756 return (error); 757 } 758 TIMESPEC_TO_TIMEVAL(&utv, &timeout); 759 error = itimerfix(&utv); 760 if (error) { 761 LIN_SDT_PROBE1(futex, linux_sys_futex, itimerfix_error, 762 error); 763 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 764 futex_put(f, wp); 765 return (error); 766 } 767 if (clockrt) { 768 microtime(&ctv); 769 timevalsub(&utv, &ctv); 770 } else if (args->op == LINUX_FUTEX_WAIT_BITSET) { 771 microuptime(&ctv); 772 timevalsub(&utv, &ctv); 773 } 774 if (utv.tv_sec < 0) 775 timevalclear(&utv); 776 timeout_hz = tvtohz(&utv); 777 } else 778 timeout_hz = 0; 779 780 error = futex_wait(f, wp, timeout_hz, args->val3); 781 break; 782 783 case LINUX_FUTEX_WAKE: 784 args->val3 = FUTEX_BITSET_MATCH_ANY; 785 /* FALLTHROUGH */ 786 787 case LINUX_FUTEX_WAKE_BITSET: 788 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr, 789 args->val, args->val3); 790 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x", 791 args->uaddr, args->val, args->val3); 792 793 error = futex_get(args->uaddr, NULL, &f, 794 flags | FUTEX_DONTCREATE); 795 if (error) { 796 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 797 return (error); 798 } 799 800 if (f == NULL) { 801 td->td_retval[0] = 0; 802 803 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 804 return (error); 805 } 806 td->td_retval[0] = futex_wake(f, args->val, args->val3); 807 futex_put(f, NULL); 808 break; 809 810 case LINUX_FUTEX_CMP_REQUEUE: 811 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue, 812 args->uaddr, args->val, args->val3, args->uaddr2, 813 args->timeout); 814 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p " 815 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x", 816 args->uaddr, args->val, args->val3, args->uaddr2, 817 args->timeout); 818 819 /* 820 * Linux allows this, we would not, it is an incorrect 821 * usage of declared ABI, so return EINVAL. 822 */ 823 if (args->uaddr == args->uaddr2) { 824 LIN_SDT_PROBE0(futex, linux_sys_futex, 825 invalid_cmp_requeue_use); 826 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 827 return (EINVAL); 828 } 829 830 error = futex_get(args->uaddr, NULL, &f, flags); 831 if (error) { 832 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 833 return (error); 834 } 835 836 /* 837 * To avoid deadlocks return EINVAL if second futex 838 * exists at this time. 839 * 840 * Glibc fall back to FUTEX_WAKE in case of any error 841 * returned by FUTEX_CMP_REQUEUE. 842 */ 843 error = futex_get(args->uaddr2, NULL, &f2, 844 flags | FUTEX_DONTEXISTS); 845 if (error) { 846 futex_put(f, NULL); 847 848 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 849 return (error); 850 } 851 error = copyin(args->uaddr, &val, sizeof(val)); 852 if (error) { 853 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 854 error); 855 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", 856 error); 857 futex_put(f2, NULL); 858 futex_put(f, NULL); 859 860 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 861 return (error); 862 } 863 if (val != args->val3) { 864 LIN_SDT_PROBE2(futex, linux_sys_futex, 865 debug_cmp_requeue_value_neq, args->val, val); 866 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x", 867 args->val, val); 868 futex_put(f2, NULL); 869 futex_put(f, NULL); 870 871 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN); 872 return (EAGAIN); 873 } 874 875 nrwake = (int)(unsigned long)args->timeout; 876 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake); 877 futex_put(f2, NULL); 878 futex_put(f, NULL); 879 break; 880 881 case LINUX_FUTEX_WAKE_OP: 882 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op, 883 args->uaddr, args->op, args->val, args->uaddr2, args->val3); 884 LINUX_CTR5(sys_futex, "WAKE_OP " 885 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x", 886 args->uaddr, args->val, args->uaddr2, args->val3, 887 args->timeout); 888 889 error = futex_get(args->uaddr, NULL, &f, flags); 890 if (error) { 891 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 892 return (error); 893 } 894 895 if (args->uaddr != args->uaddr2) 896 error = futex_get(args->uaddr2, NULL, &f2, flags); 897 if (error) { 898 futex_put(f, NULL); 899 900 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 901 return (error); 902 } 903 904 /* 905 * This function returns positive number as results and 906 * negative as errors 907 */ 908 op_ret = futex_atomic_op(td, args->val3, args->uaddr2); 909 910 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x", 911 args->uaddr, op_ret); 912 913 if (op_ret < 0) { 914 /* XXX: We don't handle the EFAULT yet. */ 915 if (op_ret != -EFAULT) { 916 if (f2 != NULL) 917 futex_put(f2, NULL); 918 futex_put(f, NULL); 919 920 LIN_SDT_PROBE1(futex, linux_sys_futex, return, 921 -op_ret); 922 return (-op_ret); 923 } else { 924 LIN_SDT_PROBE0(futex, linux_sys_futex, 925 unhandled_efault); 926 } 927 if (f2 != NULL) 928 futex_put(f2, NULL); 929 futex_put(f, NULL); 930 931 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EFAULT); 932 return (EFAULT); 933 } 934 935 ret = futex_wake(f, args->val, args->val3); 936 937 if (op_ret > 0) { 938 op_ret = 0; 939 nrwake = (int)(unsigned long)args->timeout; 940 941 if (f2 != NULL) 942 op_ret += futex_wake(f2, nrwake, args->val3); 943 else 944 op_ret += futex_wake(f, nrwake, args->val3); 945 ret += op_ret; 946 947 } 948 if (f2 != NULL) 949 futex_put(f2, NULL); 950 futex_put(f, NULL); 951 td->td_retval[0] = ret; 952 break; 953 954 case LINUX_FUTEX_LOCK_PI: 955 /* not yet implemented */ 956 pem = pem_find(td->td_proc); 957 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 958 linux_msg(td, 959 "linux_sys_futex: " 960 "unsupported futex_pi op\n"); 961 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 962 LIN_SDT_PROBE0(futex, linux_sys_futex, 963 unimplemented_lock_pi); 964 } 965 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 966 return (ENOSYS); 967 968 case LINUX_FUTEX_UNLOCK_PI: 969 /* not yet implemented */ 970 pem = pem_find(td->td_proc); 971 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 972 linux_msg(td, 973 "linux_sys_futex: " 974 "unsupported futex_pi op\n"); 975 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 976 LIN_SDT_PROBE0(futex, linux_sys_futex, 977 unimplemented_unlock_pi); 978 } 979 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 980 return (ENOSYS); 981 982 case LINUX_FUTEX_TRYLOCK_PI: 983 /* not yet implemented */ 984 pem = pem_find(td->td_proc); 985 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 986 linux_msg(td, 987 "linux_sys_futex: " 988 "unsupported futex_pi op\n"); 989 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 990 LIN_SDT_PROBE0(futex, linux_sys_futex, 991 unimplemented_trylock_pi); 992 } 993 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 994 return (ENOSYS); 995 996 case LINUX_FUTEX_REQUEUE: 997 998 /* 999 * Glibc does not use this operation since version 2.3.3, 1000 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. 1001 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when 1002 * FUTEX_REQUEUE returned EINVAL. 1003 */ 1004 pem = pem_find(td->td_proc); 1005 if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) { 1006 linux_msg(td, 1007 "linux_sys_futex: " 1008 "unsupported futex_requeue op\n"); 1009 pem->flags |= LINUX_XDEPR_REQUEUEOP; 1010 LIN_SDT_PROBE0(futex, linux_sys_futex, 1011 deprecated_requeue); 1012 } 1013 1014 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 1015 return (EINVAL); 1016 1017 case LINUX_FUTEX_WAIT_REQUEUE_PI: 1018 /* not yet implemented */ 1019 pem = pem_find(td->td_proc); 1020 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1021 linux_msg(td, 1022 "linux_sys_futex: " 1023 "unsupported futex_pi op\n"); 1024 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1025 LIN_SDT_PROBE0(futex, linux_sys_futex, 1026 unimplemented_wait_requeue_pi); 1027 } 1028 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1029 return (ENOSYS); 1030 1031 case LINUX_FUTEX_CMP_REQUEUE_PI: 1032 /* not yet implemented */ 1033 pem = pem_find(td->td_proc); 1034 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1035 linux_msg(td, 1036 "linux_sys_futex: " 1037 "unsupported futex_pi op\n"); 1038 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1039 LIN_SDT_PROBE0(futex, linux_sys_futex, 1040 unimplemented_cmp_requeue_pi); 1041 } 1042 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1043 return (ENOSYS); 1044 1045 default: 1046 linux_msg(td, 1047 "linux_sys_futex: unknown op %d\n", args->op); 1048 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation, 1049 args->op); 1050 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1051 return (ENOSYS); 1052 } 1053 1054 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 1055 return (error); 1056} 1057 1058int 1059linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) 1060{ 1061 struct linux_emuldata *em; 1062 1063 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args); 1064 1065 if (args->len != sizeof(struct linux_robust_list_head)) { 1066 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error); 1067 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL); 1068 return (EINVAL); 1069 } 1070 1071 em = em_find(td); 1072 em->robust_futexes = args->head; 1073 1074 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0); 1075 return (0); 1076} 1077 1078int 1079linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args) 1080{ 1081 struct linux_emuldata *em; 1082 struct linux_robust_list_head *head; 1083 l_size_t len = sizeof(struct linux_robust_list_head); 1084 struct thread *td2; 1085 int error = 0; 1086 1087 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args); 1088 1089 if (!args->pid) { 1090 em = em_find(td); 1091 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1092 head = em->robust_futexes; 1093 } else { 1094 td2 = tdfind(args->pid, -1); 1095 if (td2 == NULL) { 1096 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1097 ESRCH); 1098 return (ESRCH); 1099 } 1100 1101 em = em_find(td2); 1102 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1103 /* XXX: ptrace? */ 1104 if (priv_check(td, PRIV_CRED_SETUID) || 1105 priv_check(td, PRIV_CRED_SETEUID) || 1106 p_candebug(td, td2->td_proc)) { 1107 PROC_UNLOCK(td2->td_proc); 1108 1109 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1110 EPERM); 1111 return (EPERM); 1112 } 1113 head = em->robust_futexes; 1114 1115 PROC_UNLOCK(td2->td_proc); 1116 } 1117 1118 error = copyout(&len, args->len, sizeof(l_size_t)); 1119 if (error) { 1120 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1121 error); 1122 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT); 1123 return (EFAULT); 1124 } 1125 1126 error = copyout(head, args->head, sizeof(struct linux_robust_list_head)); 1127 if (error) { 1128 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1129 error); 1130 } 1131 1132 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error); 1133 return (error); 1134} 1135 1136static int 1137handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr, 1138 unsigned int pi) 1139{ 1140 uint32_t uval, nval, mval; 1141 struct futex *f; 1142 int error; 1143 1144 LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi); 1145 1146retry: 1147 error = copyin(uaddr, &uval, 4); 1148 if (error) { 1149 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error); 1150 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT); 1151 return (EFAULT); 1152 } 1153 if ((uval & FUTEX_TID_MASK) == em->em_tid) { 1154 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; 1155 nval = casuword32(uaddr, uval, mval); 1156 1157 if (nval == -1) { 1158 LIN_SDT_PROBE1(futex, handle_futex_death, return, 1159 EFAULT); 1160 return (EFAULT); 1161 } 1162 1163 if (nval != uval) 1164 goto retry; 1165 1166 if (!pi && (uval & FUTEX_WAITERS)) { 1167 error = futex_get(uaddr, NULL, &f, 1168 FUTEX_DONTCREATE | FUTEX_SHARED); 1169 if (error) { 1170 LIN_SDT_PROBE1(futex, handle_futex_death, 1171 return, error); 1172 return (error); 1173 } 1174 if (f != NULL) { 1175 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY); 1176 futex_put(f, NULL); 1177 } 1178 } 1179 } 1180 1181 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0); 1182 return (0); 1183} 1184 1185static int 1186fetch_robust_entry(struct linux_robust_list **entry, 1187 struct linux_robust_list **head, unsigned int *pi) 1188{ 1189 l_ulong uentry; 1190 int error; 1191 1192 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi); 1193 1194 error = copyin((const void *)head, &uentry, sizeof(l_ulong)); 1195 if (error) { 1196 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error); 1197 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT); 1198 return (EFAULT); 1199 } 1200 1201 *entry = (void *)(uentry & ~1UL); 1202 *pi = uentry & 1; 1203 1204 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0); 1205 return (0); 1206} 1207 1208/* This walks the list of robust futexes releasing them. */ 1209void 1210release_futexes(struct thread *td, struct linux_emuldata *em) 1211{ 1212 struct linux_robust_list_head *head = NULL; 1213 struct linux_robust_list *entry, *next_entry, *pending; 1214 unsigned int limit = 2048, pi, next_pi, pip; 1215 l_long futex_offset; 1216 int rc, error; 1217 1218 LIN_SDT_PROBE2(futex, release_futexes, entry, td, em); 1219 1220 head = em->robust_futexes; 1221 1222 if (head == NULL) { 1223 LIN_SDT_PROBE0(futex, release_futexes, return); 1224 return; 1225 } 1226 1227 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) { 1228 LIN_SDT_PROBE0(futex, release_futexes, return); 1229 return; 1230 } 1231 1232 error = copyin(&head->futex_offset, &futex_offset, 1233 sizeof(futex_offset)); 1234 if (error) { 1235 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error); 1236 LIN_SDT_PROBE0(futex, release_futexes, return); 1237 return; 1238 } 1239 1240 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) { 1241 LIN_SDT_PROBE0(futex, release_futexes, return); 1242 return; 1243 } 1244 1245 while (entry != &head->list) { 1246 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); 1247 1248 if (entry != pending) 1249 if (handle_futex_death(em, 1250 (uint32_t *)((caddr_t)entry + futex_offset), pi)) { 1251 LIN_SDT_PROBE0(futex, release_futexes, return); 1252 return; 1253 } 1254 if (rc) { 1255 LIN_SDT_PROBE0(futex, release_futexes, return); 1256 return; 1257 } 1258 1259 entry = next_entry; 1260 pi = next_pi; 1261 1262 if (!--limit) 1263 break; 1264 1265 sched_relinquish(curthread); 1266 } 1267 1268 if (pending) 1269 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip); 1270 1271 LIN_SDT_PROBE0(futex, release_futexes, return); 1272} 1273