1 /* $NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-4-Clause 5 * 6 * Copyright (c) 2009-2016 Dmitry Chagin 7 * Copyright (c) 2005 Emmanuel Dreyfus 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by Emmanuel Dreyfus 21 * 4. The name of the author may not be used to endorse or promote 22 * products derived from this software without specific prior written 23 * permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE THE AUTHOR AND CONTRIBUTORS ``AS IS'' 26 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 27 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 #if 0 41 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $"); 42 #endif 43 44 #include "opt_compat.h" 45 46 #include <sys/param.h> 47 #include <sys/systm.h> 48 #include <sys/imgact.h> 49 #include <sys/kernel.h> 50 #include <sys/ktr.h> 51 #include <sys/lock.h> 52 #include <sys/malloc.h> 53 #include <sys/mutex.h> 54 #include <sys/priv.h> 55 #include <sys/proc.h> 56 #include <sys/queue.h> 57 #include <sys/sched.h> 58 #include <sys/sdt.h> 59 #include <sys/umtx.h> 60 61 #include <vm/vm_extern.h> 62 63 #ifdef COMPAT_LINUX32 64 #include <machine/../linux32/linux.h> 65 #include <machine/../linux32/linux32_proto.h> 66 #else 67 #include <machine/../linux/linux.h> 68 #include <machine/../linux/linux_proto.h> 69 #endif 70 #include <compat/linux/linux_dtrace.h> 71 #include <compat/linux/linux_emul.h> 72 #include <compat/linux/linux_futex.h> 73 #include <compat/linux/linux_timer.h> 74 #include <compat/linux/linux_util.h> 75 76 /* DTrace init */ 77 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE); 78 79 /** 80 * Futex part for the special DTrace module "locks". 81 */ 82 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *"); 83 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *"); 84 85 /** 86 * Per futex probes. 87 */ 88 LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *"); 89 LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *"); 90 91 /** 92 * DTrace probes in this module. 93 */ 94 LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *", 95 "struct waiting_proc *"); 96 LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t", 97 "int"); 98 LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t", 99 "int"); 100 LIN_SDT_PROBE_DEFINE0(futex, futex_put, return); 101 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **", 102 "uint32_t"); 103 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int"); 104 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t", 105 "int"); 106 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *"); 107 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int"); 108 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int"); 109 LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *", 110 "struct waiting_proc **", "struct futex **"); 111 LIN_SDT_PROBE_DEFINE0(futex, futex_get, error); 112 LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int"); 113 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *", 114 "struct waiting_proc **", "struct timespec *"); 115 LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *", 116 "struct waiting_proc *", "uint32_t *", "uint32_t"); 117 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *", 118 "struct waiting_proc *"); 119 LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int"); 120 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int", 121 "uint32_t"); 122 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t", 123 "struct waiting_proc *", "uint32_t"); 124 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *"); 125 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int"); 126 LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int", 127 "struct futex *", "int"); 128 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *"); 129 LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *", 130 "struct waiting_proc *", "uint32_t"); 131 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int"); 132 LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *", 133 "struct waiting_proc **", "struct timespec *", "uint32_t"); 134 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int"); 135 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int"); 136 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *", 137 "int", "uint32_t"); 138 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int", 139 "int"); 140 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check); 141 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int"); 142 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int"); 143 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int"); 144 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *", 145 "struct linux_sys_futex_args *"); 146 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch); 147 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, copyin_error, "int"); 148 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, invalid_cmp_requeue_use); 149 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wait, "uint32_t *", 150 "uint32_t", "uint32_t"); 151 LIN_SDT_PROBE_DEFINE4(futex, linux_sys_futex, debug_wait_value_neq, 152 "uint32_t *", "uint32_t", "int", "uint32_t"); 153 LIN_SDT_PROBE_DEFINE3(futex, linux_sys_futex, debug_wake, "uint32_t *", 154 "uint32_t", "uint32_t"); 155 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_cmp_requeue, "uint32_t *", 156 "uint32_t", "uint32_t", "uint32_t *", "struct l_timespec *"); 157 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, debug_cmp_requeue_value_neq, 158 "uint32_t", "int"); 159 LIN_SDT_PROBE_DEFINE5(futex, linux_sys_futex, debug_wake_op, "uint32_t *", 160 "int", "uint32_t", "uint32_t *", "uint32_t"); 161 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unhandled_efault); 162 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_lock_pi); 163 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_unlock_pi); 164 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_trylock_pi); 165 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, deprecated_requeue); 166 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_wait_requeue_pi); 167 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_cmp_requeue_pi); 168 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, unknown_operation, "int"); 169 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, return, "int"); 170 LIN_SDT_PROBE_DEFINE2(futex, linux_set_robust_list, entry, "struct thread *", 171 "struct linux_set_robust_list_args *"); 172 LIN_SDT_PROBE_DEFINE0(futex, linux_set_robust_list, size_error); 173 LIN_SDT_PROBE_DEFINE1(futex, linux_set_robust_list, return, "int"); 174 LIN_SDT_PROBE_DEFINE2(futex, linux_get_robust_list, entry, "struct thread *", 175 "struct linux_get_robust_list_args *"); 176 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, copyout_error, "int"); 177 LIN_SDT_PROBE_DEFINE1(futex, linux_get_robust_list, return, "int"); 178 LIN_SDT_PROBE_DEFINE3(futex, handle_futex_death, entry, 179 "struct linux_emuldata *", "uint32_t *", "unsigned int"); 180 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, copyin_error, "int"); 181 LIN_SDT_PROBE_DEFINE1(futex, handle_futex_death, return, "int"); 182 LIN_SDT_PROBE_DEFINE3(futex, fetch_robust_entry, entry, 183 "struct linux_robust_list **", "struct linux_robust_list **", 184 "unsigned int *"); 185 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, copyin_error, "int"); 186 LIN_SDT_PROBE_DEFINE1(futex, fetch_robust_entry, return, "int"); 187 LIN_SDT_PROBE_DEFINE2(futex, release_futexes, entry, "struct thread *", 188 "struct linux_emuldata *"); 189 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int"); 190 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return); 191 192 struct futex; 193 194 struct waiting_proc { 195 uint32_t wp_flags; 196 struct futex *wp_futex; 197 TAILQ_ENTRY(waiting_proc) wp_list; 198 }; 199 200 struct futex { 201 struct mtx f_lck; 202 uint32_t *f_uaddr; /* user-supplied value, for debug */ 203 struct umtx_key f_key; 204 uint32_t f_refcount; 205 uint32_t f_bitset; 206 LIST_ENTRY(futex) f_list; 207 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc; 208 }; 209 210 #define FUTEX_LOCK(f) mtx_lock(&(f)->f_lck) 211 #define FUTEX_LOCKED(f) mtx_owned(&(f)->f_lck) 212 #define FUTEX_UNLOCK(f) mtx_unlock(&(f)->f_lck) 213 #define FUTEX_INIT(f) do { \ 214 mtx_init(&(f)->f_lck, "ftlk", NULL, \ 215 MTX_DUPOK); \ 216 LIN_SDT_PROBE1(futex, futex, create, \ 217 &(f)->f_lck); \ 218 } while (0) 219 #define FUTEX_DESTROY(f) do { \ 220 LIN_SDT_PROBE1(futex, futex, destroy, \ 221 &(f)->f_lck); \ 222 mtx_destroy(&(f)->f_lck); \ 223 } while (0) 224 #define FUTEX_ASSERT_LOCKED(f) mtx_assert(&(f)->f_lck, MA_OWNED) 225 #define FUTEX_ASSERT_UNLOCKED(f) mtx_assert(&(f)->f_lck, MA_NOTOWNED) 226 227 #define FUTEXES_LOCK do { \ 228 mtx_lock(&futex_mtx); \ 229 LIN_SDT_PROBE1(locks, futex_mtx, \ 230 locked, &futex_mtx); \ 231 } while (0) 232 #define FUTEXES_UNLOCK do { \ 233 LIN_SDT_PROBE1(locks, futex_mtx, \ 234 unlock, &futex_mtx); \ 235 mtx_unlock(&futex_mtx); \ 236 } while (0) 237 238 /* flags for futex_get() */ 239 #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */ 240 #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */ 241 #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */ 242 #define FUTEX_SHARED 0x8 /* shared futex */ 243 #define FUTEX_DONTLOCK 0x10 /* don't lock futex */ 244 245 /* wp_flags */ 246 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list 247 * of futex where thread sleep to wp_list 248 * of another futex. 249 */ 250 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex 251 * wp_list to prevent double wakeup. 252 */ 253 254 static void futex_put(struct futex *, struct waiting_proc *); 255 static int futex_get0(uint32_t *, struct futex **f, uint32_t); 256 static int futex_get(uint32_t *, struct waiting_proc **, struct futex **, 257 uint32_t); 258 static int futex_sleep(struct futex *, struct waiting_proc *, struct timespec *); 259 static int futex_wake(struct futex *, int, uint32_t); 260 static int futex_requeue(struct futex *, int, struct futex *, int); 261 static int futex_copyin_timeout(int, struct l_timespec *, int, 262 struct timespec *); 263 static int futex_wait(struct futex *, struct waiting_proc *, struct timespec *, 264 uint32_t); 265 static void futex_lock(struct futex *); 266 static void futex_unlock(struct futex *); 267 static int futex_atomic_op(struct thread *, int, uint32_t *); 268 static int handle_futex_death(struct linux_emuldata *, uint32_t *, 269 unsigned int); 270 static int fetch_robust_entry(struct linux_robust_list **, 271 struct linux_robust_list **, unsigned int *); 272 273 static int 274 futex_copyin_timeout(int op, struct l_timespec *luts, int clockrt, 275 struct timespec *ts) 276 { 277 struct l_timespec lts; 278 struct timespec kts; 279 int error; 280 281 error = copyin(luts, <s, sizeof(lts)); 282 if (error) 283 return (error); 284 285 error = linux_to_native_timespec(ts, <s); 286 if (error) 287 return (error); 288 if (clockrt) { 289 nanotime(&kts); 290 timespecsub(ts, &kts, ts); 291 } else if (op == LINUX_FUTEX_WAIT_BITSET) { 292 nanouptime(&kts); 293 timespecsub(ts, &kts, ts); 294 } 295 return (error); 296 } 297 298 static void 299 futex_put(struct futex *f, struct waiting_proc *wp) 300 { 301 LIN_SDT_PROBE2(futex, futex_put, entry, f, wp); 302 303 if (wp != NULL) { 304 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0) 305 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 306 free(wp, M_FUTEX_WP); 307 } 308 309 FUTEXES_LOCK; 310 if (--f->f_refcount == 0) { 311 LIST_REMOVE(f, f_list); 312 FUTEXES_UNLOCK; 313 if (FUTEX_LOCKED(f)) 314 futex_unlock(f); 315 316 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr, 317 f->f_refcount, f->f_key.shared); 318 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d " 319 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared); 320 umtx_key_release(&f->f_key); 321 FUTEX_DESTROY(f); 322 free(f, M_FUTEX); 323 324 LIN_SDT_PROBE0(futex, futex_put, return); 325 return; 326 } 327 328 LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount, 329 f->f_key.shared); 330 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d", 331 f->f_uaddr, f->f_refcount, f->f_key.shared); 332 if (FUTEX_LOCKED(f)) 333 futex_unlock(f); 334 FUTEXES_UNLOCK; 335 336 LIN_SDT_PROBE0(futex, futex_put, return); 337 } 338 339 static int 340 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags) 341 { 342 struct futex *f, *tmpf; 343 struct umtx_key key; 344 int error; 345 346 LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags); 347 348 *newf = tmpf = NULL; 349 350 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ? 351 AUTO_SHARE : THREAD_SHARE, &key); 352 if (error) { 353 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error); 354 LIN_SDT_PROBE1(futex, futex_get0, return, error); 355 return (error); 356 } 357 retry: 358 FUTEXES_LOCK; 359 LIST_FOREACH(f, &futex_list, f_list) { 360 if (umtx_key_match(&f->f_key, &key)) { 361 if (tmpf != NULL) { 362 if (FUTEX_LOCKED(tmpf)) 363 futex_unlock(tmpf); 364 FUTEX_DESTROY(tmpf); 365 free(tmpf, M_FUTEX); 366 } 367 if (flags & FUTEX_DONTEXISTS) { 368 FUTEXES_UNLOCK; 369 umtx_key_release(&key); 370 371 LIN_SDT_PROBE1(futex, futex_get0, return, 372 EINVAL); 373 return (EINVAL); 374 } 375 376 /* 377 * Increment refcount of the found futex to 378 * prevent it from deallocation before FUTEX_LOCK() 379 */ 380 ++f->f_refcount; 381 FUTEXES_UNLOCK; 382 umtx_key_release(&key); 383 384 if ((flags & FUTEX_DONTLOCK) == 0) 385 futex_lock(f); 386 *newf = f; 387 LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr, 388 f->f_refcount, f->f_key.shared); 389 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d", 390 uaddr, f->f_refcount, f->f_key.shared); 391 392 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 393 return (0); 394 } 395 } 396 397 if (flags & FUTEX_DONTCREATE) { 398 FUTEXES_UNLOCK; 399 umtx_key_release(&key); 400 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr); 401 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr); 402 403 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 404 return (0); 405 } 406 407 if (tmpf == NULL) { 408 FUTEXES_UNLOCK; 409 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO); 410 tmpf->f_uaddr = uaddr; 411 tmpf->f_key = key; 412 tmpf->f_refcount = 1; 413 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY; 414 FUTEX_INIT(tmpf); 415 TAILQ_INIT(&tmpf->f_waiting_proc); 416 417 /* 418 * Lock the new futex before an insert into the futex_list 419 * to prevent futex usage by other. 420 */ 421 if ((flags & FUTEX_DONTLOCK) == 0) 422 futex_lock(tmpf); 423 goto retry; 424 } 425 426 LIST_INSERT_HEAD(&futex_list, tmpf, f_list); 427 FUTEXES_UNLOCK; 428 429 LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount, 430 tmpf->f_key.shared); 431 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new", 432 uaddr, tmpf->f_refcount, tmpf->f_key.shared); 433 *newf = tmpf; 434 435 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 436 return (0); 437 } 438 439 static int 440 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f, 441 uint32_t flags) 442 { 443 int error; 444 445 LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f); 446 447 if (flags & FUTEX_CREATE_WP) { 448 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK); 449 (*wp)->wp_flags = 0; 450 } 451 error = futex_get0(uaddr, f, flags); 452 if (error) { 453 LIN_SDT_PROBE0(futex, futex_get, error); 454 455 if (flags & FUTEX_CREATE_WP) 456 free(*wp, M_FUTEX_WP); 457 458 LIN_SDT_PROBE1(futex, futex_get, return, error); 459 return (error); 460 } 461 if (flags & FUTEX_CREATE_WP) { 462 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list); 463 (*wp)->wp_futex = *f; 464 } 465 466 LIN_SDT_PROBE1(futex, futex_get, return, error); 467 return (error); 468 } 469 470 static inline void 471 futex_lock(struct futex *f) 472 { 473 474 LINUX_CTR3(sys_futex, "futex_lock uaddr %p ref %d shared %d", 475 f->f_uaddr, f->f_refcount, f->f_key.shared); 476 FUTEX_ASSERT_UNLOCKED(f); 477 FUTEX_LOCK(f); 478 } 479 480 static inline void 481 futex_unlock(struct futex *f) 482 { 483 484 LINUX_CTR3(sys_futex, "futex_unlock uaddr %p ref %d shared %d", 485 f->f_uaddr, f->f_refcount, f->f_key.shared); 486 FUTEX_ASSERT_LOCKED(f); 487 FUTEX_UNLOCK(f); 488 } 489 490 static int 491 futex_sleep(struct futex *f, struct waiting_proc *wp, struct timespec *ts) 492 { 493 struct timespec uts; 494 sbintime_t sbt, prec, tmp; 495 time_t over; 496 int error; 497 498 FUTEX_ASSERT_LOCKED(f); 499 if (ts != NULL) { 500 uts = *ts; 501 if (uts.tv_sec > INT32_MAX / 2) { 502 over = uts.tv_sec - INT32_MAX / 2; 503 uts.tv_sec -= over; 504 } 505 tmp = tstosbt(uts); 506 if (TIMESEL(&sbt, tmp)) 507 sbt += tc_tick_sbt; 508 sbt += tmp; 509 prec = tmp; 510 prec >>= tc_precexp; 511 } else { 512 sbt = 0; 513 prec = 0; 514 } 515 LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, sbt); 516 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %ld ref %d", 517 f->f_uaddr, wp, sbt, f->f_refcount); 518 519 error = msleep_sbt(wp, &f->f_lck, PCATCH, "futex", sbt, prec, C_ABSOLUTE); 520 if (wp->wp_flags & FUTEX_WP_REQUEUED) { 521 KASSERT(f != wp->wp_futex, ("futex != wp_futex")); 522 523 if (error) { 524 LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error, 525 f->f_uaddr, wp, wp->wp_futex->f_uaddr, 526 wp->wp_futex->f_refcount); 527 } 528 529 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp" 530 " %p requeued uaddr %p ref %d", 531 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr, 532 wp->wp_futex->f_refcount); 533 futex_put(f, NULL); 534 f = wp->wp_futex; 535 futex_lock(f); 536 } else { 537 if (error) { 538 LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error, 539 f->f_uaddr, wp); 540 } 541 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p", 542 error, f->f_uaddr, wp); 543 } 544 545 futex_put(f, wp); 546 547 LIN_SDT_PROBE1(futex, futex_sleep, return, error); 548 return (error); 549 } 550 551 static int 552 futex_wake(struct futex *f, int n, uint32_t bitset) 553 { 554 struct waiting_proc *wp, *wpt; 555 int count = 0; 556 557 LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset); 558 559 if (bitset == 0) { 560 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL); 561 return (EINVAL); 562 } 563 564 FUTEX_ASSERT_LOCKED(f); 565 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 566 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp, 567 f->f_refcount); 568 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d", 569 f->f_uaddr, wp, f->f_refcount); 570 /* 571 * Unless we find a matching bit in 572 * the bitset, continue searching. 573 */ 574 if (!(wp->wp_futex->f_bitset & bitset)) 575 continue; 576 577 wp->wp_flags |= FUTEX_WP_REMOVED; 578 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 579 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp); 580 wakeup_one(wp); 581 if (++count == n) 582 break; 583 } 584 585 LIN_SDT_PROBE1(futex, futex_wake, return, count); 586 return (count); 587 } 588 589 static int 590 futex_requeue(struct futex *f, int n, struct futex *f2, int n2) 591 { 592 struct waiting_proc *wp, *wpt; 593 int count = 0; 594 595 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2); 596 597 FUTEX_ASSERT_LOCKED(f); 598 FUTEX_ASSERT_LOCKED(f2); 599 600 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 601 if (++count <= n) { 602 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p", 603 f->f_uaddr, wp); 604 wp->wp_flags |= FUTEX_WP_REMOVED; 605 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 606 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp); 607 wakeup_one(wp); 608 } else { 609 LIN_SDT_PROBE3(futex, futex_requeue, requeue, 610 f->f_uaddr, wp, f2->f_uaddr); 611 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p", 612 f->f_uaddr, wp, f2->f_uaddr); 613 wp->wp_flags |= FUTEX_WP_REQUEUED; 614 /* Move wp to wp_list of f2 futex */ 615 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 616 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list); 617 618 /* 619 * Thread which sleeps on wp after waking should 620 * acquire f2 lock, so increment refcount of f2 to 621 * prevent it from premature deallocation. 622 */ 623 wp->wp_futex = f2; 624 FUTEXES_LOCK; 625 ++f2->f_refcount; 626 FUTEXES_UNLOCK; 627 if (count - n >= n2) 628 break; 629 } 630 } 631 632 LIN_SDT_PROBE1(futex, futex_requeue, return, count); 633 return (count); 634 } 635 636 static int 637 futex_wait(struct futex *f, struct waiting_proc *wp, struct timespec *ts, 638 uint32_t bitset) 639 { 640 int error; 641 642 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, ts, bitset); 643 644 if (bitset == 0) { 645 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL); 646 futex_put(f, wp); 647 return (EINVAL); 648 } 649 650 f->f_bitset = bitset; 651 error = futex_sleep(f, wp, ts); 652 if (error) 653 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error); 654 if (error == EWOULDBLOCK) 655 error = ETIMEDOUT; 656 657 LIN_SDT_PROBE1(futex, futex_wait, return, error); 658 return (error); 659 } 660 661 static int 662 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr) 663 { 664 int op = (encoded_op >> 28) & 7; 665 int cmp = (encoded_op >> 24) & 15; 666 int oparg = (encoded_op << 8) >> 20; 667 int cmparg = (encoded_op << 20) >> 20; 668 int oldval = 0, ret; 669 670 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr); 671 672 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 673 oparg = 1 << oparg; 674 675 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg, 676 cmparg); 677 678 /* XXX: Linux verifies access here and returns EFAULT */ 679 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check); 680 681 switch (op) { 682 case FUTEX_OP_SET: 683 ret = futex_xchgl(oparg, uaddr, &oldval); 684 break; 685 case FUTEX_OP_ADD: 686 ret = futex_addl(oparg, uaddr, &oldval); 687 break; 688 case FUTEX_OP_OR: 689 ret = futex_orl(oparg, uaddr, &oldval); 690 break; 691 case FUTEX_OP_ANDN: 692 ret = futex_andl(~oparg, uaddr, &oldval); 693 break; 694 case FUTEX_OP_XOR: 695 ret = futex_xorl(oparg, uaddr, &oldval); 696 break; 697 default: 698 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op); 699 ret = -ENOSYS; 700 break; 701 } 702 703 if (ret) { 704 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 705 return (ret); 706 } 707 708 switch (cmp) { 709 case FUTEX_OP_CMP_EQ: 710 ret = (oldval == cmparg); 711 break; 712 case FUTEX_OP_CMP_NE: 713 ret = (oldval != cmparg); 714 break; 715 case FUTEX_OP_CMP_LT: 716 ret = (oldval < cmparg); 717 break; 718 case FUTEX_OP_CMP_GE: 719 ret = (oldval >= cmparg); 720 break; 721 case FUTEX_OP_CMP_LE: 722 ret = (oldval <= cmparg); 723 break; 724 case FUTEX_OP_CMP_GT: 725 ret = (oldval > cmparg); 726 break; 727 default: 728 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp); 729 ret = -ENOSYS; 730 } 731 732 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 733 return (ret); 734 } 735 736 int 737 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) 738 { 739 int clockrt, nrwake, op_ret, ret; 740 struct linux_pemuldata *pem; 741 struct waiting_proc *wp; 742 struct futex *f, *f2; 743 struct timespec uts, *ts; 744 int error, save; 745 uint32_t flags, val; 746 747 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args); 748 749 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { 750 flags = 0; 751 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG; 752 } else 753 flags = FUTEX_SHARED; 754 755 /* 756 * Currently support for switching between CLOCK_MONOTONIC and 757 * CLOCK_REALTIME is not present. However Linux forbids the use of 758 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and 759 * FUTEX_WAIT_REQUEUE_PI. 760 */ 761 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME; 762 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME; 763 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET && 764 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) { 765 LIN_SDT_PROBE0(futex, linux_sys_futex, 766 unimplemented_clockswitch); 767 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 768 return (ENOSYS); 769 } 770 771 error = 0; 772 f = f2 = NULL; 773 774 switch (args->op) { 775 case LINUX_FUTEX_WAIT: 776 args->val3 = FUTEX_BITSET_MATCH_ANY; 777 /* FALLTHROUGH */ 778 779 case LINUX_FUTEX_WAIT_BITSET: 780 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr, 781 args->val, args->val3); 782 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x", 783 args->uaddr, args->val, args->val3); 784 785 if (args->timeout != NULL) { 786 error = futex_copyin_timeout(args->op, args->timeout, 787 clockrt, &uts); 788 if (error) { 789 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 790 error); 791 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 792 return (error); 793 } 794 ts = &uts; 795 } else 796 ts = NULL; 797 798 retry0: 799 error = futex_get(args->uaddr, &wp, &f, 800 flags | FUTEX_CREATE_WP); 801 if (error) { 802 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 803 return (error); 804 } 805 806 error = copyin_nofault(args->uaddr, &val, sizeof(val)); 807 if (error) { 808 futex_put(f, wp); 809 error = copyin(args->uaddr, &val, sizeof(val)); 810 if (error == 0) 811 goto retry0; 812 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 813 error); 814 LINUX_CTR1(sys_futex, "WAIT copyin failed %d", 815 error); 816 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 817 return (error); 818 } 819 if (val != args->val) { 820 LIN_SDT_PROBE4(futex, linux_sys_futex, 821 debug_wait_value_neq, args->uaddr, args->val, val, 822 args->val3); 823 LINUX_CTR3(sys_futex, 824 "WAIT uaddr %p val 0x%x != uval 0x%x", 825 args->uaddr, args->val, val); 826 futex_put(f, wp); 827 828 LIN_SDT_PROBE1(futex, linux_sys_futex, return, 829 EWOULDBLOCK); 830 return (EWOULDBLOCK); 831 } 832 833 error = futex_wait(f, wp, ts, args->val3); 834 break; 835 836 case LINUX_FUTEX_WAKE: 837 args->val3 = FUTEX_BITSET_MATCH_ANY; 838 /* FALLTHROUGH */ 839 840 case LINUX_FUTEX_WAKE_BITSET: 841 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr, 842 args->val, args->val3); 843 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x", 844 args->uaddr, args->val, args->val3); 845 846 error = futex_get(args->uaddr, NULL, &f, 847 flags | FUTEX_DONTCREATE); 848 if (error) { 849 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 850 return (error); 851 } 852 853 if (f == NULL) { 854 td->td_retval[0] = 0; 855 856 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 857 return (error); 858 } 859 td->td_retval[0] = futex_wake(f, args->val, args->val3); 860 futex_put(f, NULL); 861 break; 862 863 case LINUX_FUTEX_CMP_REQUEUE: 864 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue, 865 args->uaddr, args->val, args->val3, args->uaddr2, 866 args->timeout); 867 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p " 868 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x", 869 args->uaddr, args->val, args->val3, args->uaddr2, 870 args->timeout); 871 872 /* 873 * Linux allows this, we would not, it is an incorrect 874 * usage of declared ABI, so return EINVAL. 875 */ 876 if (args->uaddr == args->uaddr2) { 877 LIN_SDT_PROBE0(futex, linux_sys_futex, 878 invalid_cmp_requeue_use); 879 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 880 return (EINVAL); 881 } 882 883 retry1: 884 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK); 885 if (error) { 886 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 887 return (error); 888 } 889 890 /* 891 * To avoid deadlocks return EINVAL if second futex 892 * exists at this time. 893 * 894 * Glibc fall back to FUTEX_WAKE in case of any error 895 * returned by FUTEX_CMP_REQUEUE. 896 */ 897 error = futex_get(args->uaddr2, NULL, &f2, 898 flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK); 899 if (error) { 900 futex_put(f, NULL); 901 902 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 903 return (error); 904 } 905 futex_lock(f); 906 futex_lock(f2); 907 error = copyin_nofault(args->uaddr, &val, sizeof(val)); 908 if (error) { 909 futex_put(f2, NULL); 910 futex_put(f, NULL); 911 error = copyin(args->uaddr, &val, sizeof(val)); 912 if (error == 0) 913 goto retry1; 914 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 915 error); 916 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", 917 error); 918 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 919 return (error); 920 } 921 if (val != args->val3) { 922 LIN_SDT_PROBE2(futex, linux_sys_futex, 923 debug_cmp_requeue_value_neq, args->val, val); 924 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x", 925 args->val, val); 926 futex_put(f2, NULL); 927 futex_put(f, NULL); 928 929 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN); 930 return (EAGAIN); 931 } 932 933 nrwake = (int)(unsigned long)args->timeout; 934 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake); 935 futex_put(f2, NULL); 936 futex_put(f, NULL); 937 break; 938 939 case LINUX_FUTEX_WAKE_OP: 940 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op, 941 args->uaddr, args->op, args->val, args->uaddr2, args->val3); 942 LINUX_CTR5(sys_futex, "WAKE_OP " 943 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x", 944 args->uaddr, args->val, args->uaddr2, args->val3, 945 args->timeout); 946 947 if (args->uaddr == args->uaddr2) { 948 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 949 return (EINVAL); 950 } 951 952 retry2: 953 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK); 954 if (error) { 955 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 956 return (error); 957 } 958 959 error = futex_get(args->uaddr2, NULL, &f2, flags | FUTEX_DONTLOCK); 960 if (error) { 961 futex_put(f, NULL); 962 963 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 964 return (error); 965 } 966 futex_lock(f); 967 futex_lock(f2); 968 969 /* 970 * This function returns positive number as results and 971 * negative as errors 972 */ 973 save = vm_fault_disable_pagefaults(); 974 op_ret = futex_atomic_op(td, args->val3, args->uaddr2); 975 vm_fault_enable_pagefaults(save); 976 977 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x", 978 args->uaddr, op_ret); 979 980 if (op_ret < 0) { 981 if (f2 != NULL) 982 futex_put(f2, NULL); 983 futex_put(f, NULL); 984 error = copyin(args->uaddr2, &val, sizeof(val)); 985 if (error == 0) 986 goto retry2; 987 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 988 return (error); 989 } 990 991 ret = futex_wake(f, args->val, args->val3); 992 993 if (op_ret > 0) { 994 op_ret = 0; 995 nrwake = (int)(unsigned long)args->timeout; 996 997 if (f2 != NULL) 998 op_ret += futex_wake(f2, nrwake, args->val3); 999 else 1000 op_ret += futex_wake(f, nrwake, args->val3); 1001 ret += op_ret; 1002 } 1003 if (f2 != NULL) 1004 futex_put(f2, NULL); 1005 futex_put(f, NULL); 1006 td->td_retval[0] = ret; 1007 break; 1008 1009 case LINUX_FUTEX_LOCK_PI: 1010 /* not yet implemented */ 1011 pem = pem_find(td->td_proc); 1012 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1013 linux_msg(td, "unsupported FUTEX_LOCK_PI"); 1014 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1015 LIN_SDT_PROBE0(futex, linux_sys_futex, 1016 unimplemented_lock_pi); 1017 } 1018 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1019 return (ENOSYS); 1020 1021 case LINUX_FUTEX_UNLOCK_PI: 1022 /* not yet implemented */ 1023 pem = pem_find(td->td_proc); 1024 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1025 linux_msg(td, "unsupported FUTEX_UNLOCK_PI"); 1026 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1027 LIN_SDT_PROBE0(futex, linux_sys_futex, 1028 unimplemented_unlock_pi); 1029 } 1030 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1031 return (ENOSYS); 1032 1033 case LINUX_FUTEX_TRYLOCK_PI: 1034 /* not yet implemented */ 1035 pem = pem_find(td->td_proc); 1036 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1037 linux_msg(td, "unsupported FUTEX_TRYLOCK_PI"); 1038 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1039 LIN_SDT_PROBE0(futex, linux_sys_futex, 1040 unimplemented_trylock_pi); 1041 } 1042 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1043 return (ENOSYS); 1044 1045 case LINUX_FUTEX_REQUEUE: 1046 /* 1047 * Glibc does not use this operation since version 2.3.3, 1048 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. 1049 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when 1050 * FUTEX_REQUEUE returned EINVAL. 1051 */ 1052 pem = pem_find(td->td_proc); 1053 if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) { 1054 linux_msg(td, "unsupported FUTEX_REQUEUE"); 1055 pem->flags |= LINUX_XDEPR_REQUEUEOP; 1056 LIN_SDT_PROBE0(futex, linux_sys_futex, 1057 deprecated_requeue); 1058 } 1059 1060 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 1061 return (EINVAL); 1062 1063 case LINUX_FUTEX_WAIT_REQUEUE_PI: 1064 /* not yet implemented */ 1065 pem = pem_find(td->td_proc); 1066 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1067 linux_msg(td, "unsupported FUTEX_WAIT_REQUEUE_PI"); 1068 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1069 LIN_SDT_PROBE0(futex, linux_sys_futex, 1070 unimplemented_wait_requeue_pi); 1071 } 1072 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1073 return (ENOSYS); 1074 1075 case LINUX_FUTEX_CMP_REQUEUE_PI: 1076 /* not yet implemented */ 1077 pem = pem_find(td->td_proc); 1078 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1079 linux_msg(td, "unsupported FUTEX_CMP_REQUEUE_PI"); 1080 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1081 LIN_SDT_PROBE0(futex, linux_sys_futex, 1082 unimplemented_cmp_requeue_pi); 1083 } 1084 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1085 return (ENOSYS); 1086 1087 default: 1088 linux_msg(td, "unsupported futex op %d", args->op); 1089 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation, 1090 args->op); 1091 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1092 return (ENOSYS); 1093 } 1094 1095 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 1096 return (error); 1097 } 1098 1099 int 1100 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) 1101 { 1102 struct linux_emuldata *em; 1103 1104 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args); 1105 1106 if (args->len != sizeof(struct linux_robust_list_head)) { 1107 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error); 1108 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL); 1109 return (EINVAL); 1110 } 1111 1112 em = em_find(td); 1113 em->robust_futexes = args->head; 1114 1115 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0); 1116 return (0); 1117 } 1118 1119 int 1120 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args) 1121 { 1122 struct linux_emuldata *em; 1123 struct linux_robust_list_head *head; 1124 l_size_t len = sizeof(struct linux_robust_list_head); 1125 struct thread *td2; 1126 int error = 0; 1127 1128 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args); 1129 1130 if (!args->pid) { 1131 em = em_find(td); 1132 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1133 head = em->robust_futexes; 1134 } else { 1135 td2 = tdfind(args->pid, -1); 1136 if (td2 == NULL) { 1137 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1138 ESRCH); 1139 return (ESRCH); 1140 } 1141 if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) { 1142 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1143 EPERM); 1144 PROC_UNLOCK(td2->td_proc); 1145 return (EPERM); 1146 } 1147 1148 em = em_find(td2); 1149 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1150 /* XXX: ptrace? */ 1151 if (priv_check(td, PRIV_CRED_SETUID) || 1152 priv_check(td, PRIV_CRED_SETEUID) || 1153 p_candebug(td, td2->td_proc)) { 1154 PROC_UNLOCK(td2->td_proc); 1155 1156 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1157 EPERM); 1158 return (EPERM); 1159 } 1160 head = em->robust_futexes; 1161 1162 PROC_UNLOCK(td2->td_proc); 1163 } 1164 1165 error = copyout(&len, args->len, sizeof(l_size_t)); 1166 if (error) { 1167 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1168 error); 1169 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT); 1170 return (EFAULT); 1171 } 1172 1173 error = copyout(&head, args->head, sizeof(head)); 1174 if (error) { 1175 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1176 error); 1177 } 1178 1179 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error); 1180 return (error); 1181 } 1182 1183 static int 1184 handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr, 1185 unsigned int pi) 1186 { 1187 uint32_t uval, nval, mval; 1188 struct futex *f; 1189 int error; 1190 1191 LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi); 1192 1193 retry: 1194 error = copyin(uaddr, &uval, 4); 1195 if (error) { 1196 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error); 1197 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT); 1198 return (EFAULT); 1199 } 1200 if ((uval & FUTEX_TID_MASK) == em->em_tid) { 1201 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; 1202 nval = casuword32(uaddr, uval, mval); 1203 1204 if (nval == -1) { 1205 LIN_SDT_PROBE1(futex, handle_futex_death, return, 1206 EFAULT); 1207 return (EFAULT); 1208 } 1209 1210 if (nval != uval) 1211 goto retry; 1212 1213 if (!pi && (uval & FUTEX_WAITERS)) { 1214 error = futex_get(uaddr, NULL, &f, 1215 FUTEX_DONTCREATE | FUTEX_SHARED); 1216 if (error) { 1217 LIN_SDT_PROBE1(futex, handle_futex_death, 1218 return, error); 1219 return (error); 1220 } 1221 if (f != NULL) { 1222 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY); 1223 futex_put(f, NULL); 1224 } 1225 } 1226 } 1227 1228 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0); 1229 return (0); 1230 } 1231 1232 static int 1233 fetch_robust_entry(struct linux_robust_list **entry, 1234 struct linux_robust_list **head, unsigned int *pi) 1235 { 1236 l_ulong uentry; 1237 int error; 1238 1239 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi); 1240 1241 error = copyin((const void *)head, &uentry, sizeof(l_ulong)); 1242 if (error) { 1243 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error); 1244 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT); 1245 return (EFAULT); 1246 } 1247 1248 *entry = (void *)(uentry & ~1UL); 1249 *pi = uentry & 1; 1250 1251 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0); 1252 return (0); 1253 } 1254 1255 /* This walks the list of robust futexes releasing them. */ 1256 void 1257 release_futexes(struct thread *td, struct linux_emuldata *em) 1258 { 1259 struct linux_robust_list_head *head = NULL; 1260 struct linux_robust_list *entry, *next_entry, *pending; 1261 unsigned int limit = 2048, pi, next_pi, pip; 1262 l_long futex_offset; 1263 int rc, error; 1264 1265 LIN_SDT_PROBE2(futex, release_futexes, entry, td, em); 1266 1267 head = em->robust_futexes; 1268 1269 if (head == NULL) { 1270 LIN_SDT_PROBE0(futex, release_futexes, return); 1271 return; 1272 } 1273 1274 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) { 1275 LIN_SDT_PROBE0(futex, release_futexes, return); 1276 return; 1277 } 1278 1279 error = copyin(&head->futex_offset, &futex_offset, 1280 sizeof(futex_offset)); 1281 if (error) { 1282 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error); 1283 LIN_SDT_PROBE0(futex, release_futexes, return); 1284 return; 1285 } 1286 1287 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) { 1288 LIN_SDT_PROBE0(futex, release_futexes, return); 1289 return; 1290 } 1291 1292 while (entry != &head->list) { 1293 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); 1294 1295 if (entry != pending) 1296 if (handle_futex_death(em, 1297 (uint32_t *)((caddr_t)entry + futex_offset), pi)) { 1298 LIN_SDT_PROBE0(futex, release_futexes, return); 1299 return; 1300 } 1301 if (rc) { 1302 LIN_SDT_PROBE0(futex, release_futexes, return); 1303 return; 1304 } 1305 1306 entry = next_entry; 1307 pi = next_pi; 1308 1309 if (!--limit) 1310 break; 1311 1312 sched_relinquish(curthread); 1313 } 1314 1315 if (pending) 1316 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip); 1317 1318 LIN_SDT_PROBE0(futex, release_futexes, return); 1319 } 1320