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 return (EINVAL); 647 } 648 649 f->f_bitset = bitset; 650 error = futex_sleep(f, wp, ts); 651 if (error) 652 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error); 653 if (error == EWOULDBLOCK) 654 error = ETIMEDOUT; 655 656 LIN_SDT_PROBE1(futex, futex_wait, return, error); 657 return (error); 658 } 659 660 static int 661 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr) 662 { 663 int op = (encoded_op >> 28) & 7; 664 int cmp = (encoded_op >> 24) & 15; 665 int oparg = (encoded_op << 8) >> 20; 666 int cmparg = (encoded_op << 20) >> 20; 667 int oldval = 0, ret; 668 669 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr); 670 671 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 672 oparg = 1 << oparg; 673 674 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg, 675 cmparg); 676 677 /* XXX: Linux verifies access here and returns EFAULT */ 678 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check); 679 680 switch (op) { 681 case FUTEX_OP_SET: 682 ret = futex_xchgl(oparg, uaddr, &oldval); 683 break; 684 case FUTEX_OP_ADD: 685 ret = futex_addl(oparg, uaddr, &oldval); 686 break; 687 case FUTEX_OP_OR: 688 ret = futex_orl(oparg, uaddr, &oldval); 689 break; 690 case FUTEX_OP_ANDN: 691 ret = futex_andl(~oparg, uaddr, &oldval); 692 break; 693 case FUTEX_OP_XOR: 694 ret = futex_xorl(oparg, uaddr, &oldval); 695 break; 696 default: 697 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op); 698 ret = -ENOSYS; 699 break; 700 } 701 702 if (ret) { 703 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 704 return (ret); 705 } 706 707 switch (cmp) { 708 case FUTEX_OP_CMP_EQ: 709 ret = (oldval == cmparg); 710 break; 711 case FUTEX_OP_CMP_NE: 712 ret = (oldval != cmparg); 713 break; 714 case FUTEX_OP_CMP_LT: 715 ret = (oldval < cmparg); 716 break; 717 case FUTEX_OP_CMP_GE: 718 ret = (oldval >= cmparg); 719 break; 720 case FUTEX_OP_CMP_LE: 721 ret = (oldval <= cmparg); 722 break; 723 case FUTEX_OP_CMP_GT: 724 ret = (oldval > cmparg); 725 break; 726 default: 727 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp); 728 ret = -ENOSYS; 729 } 730 731 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 732 return (ret); 733 } 734 735 int 736 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) 737 { 738 int clockrt, nrwake, op_ret, ret; 739 struct linux_pemuldata *pem; 740 struct waiting_proc *wp; 741 struct futex *f, *f2; 742 struct timespec uts, *ts; 743 int error, save; 744 uint32_t flags, val; 745 746 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args); 747 748 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { 749 flags = 0; 750 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG; 751 } else 752 flags = FUTEX_SHARED; 753 754 /* 755 * Currently support for switching between CLOCK_MONOTONIC and 756 * CLOCK_REALTIME is not present. However Linux forbids the use of 757 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and 758 * FUTEX_WAIT_REQUEUE_PI. 759 */ 760 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME; 761 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME; 762 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET && 763 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) { 764 LIN_SDT_PROBE0(futex, linux_sys_futex, 765 unimplemented_clockswitch); 766 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 767 return (ENOSYS); 768 } 769 770 error = 0; 771 f = f2 = NULL; 772 773 switch (args->op) { 774 case LINUX_FUTEX_WAIT: 775 args->val3 = FUTEX_BITSET_MATCH_ANY; 776 /* FALLTHROUGH */ 777 778 case LINUX_FUTEX_WAIT_BITSET: 779 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr, 780 args->val, args->val3); 781 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x", 782 args->uaddr, args->val, args->val3); 783 784 if (args->timeout != NULL) { 785 error = futex_copyin_timeout(args->op, args->timeout, 786 clockrt, &uts); 787 if (error) { 788 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 789 error); 790 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 791 return (error); 792 } 793 ts = &uts; 794 } else 795 ts = NULL; 796 797 retry0: 798 error = futex_get(args->uaddr, &wp, &f, 799 flags | FUTEX_CREATE_WP); 800 if (error) { 801 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 802 return (error); 803 } 804 805 error = copyin_nofault(args->uaddr, &val, sizeof(val)); 806 if (error) { 807 futex_put(f, wp); 808 error = copyin(args->uaddr, &val, sizeof(val)); 809 if (error == 0) 810 goto retry0; 811 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 812 error); 813 LINUX_CTR1(sys_futex, "WAIT copyin failed %d", 814 error); 815 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 816 return (error); 817 } 818 if (val != args->val) { 819 LIN_SDT_PROBE4(futex, linux_sys_futex, 820 debug_wait_value_neq, args->uaddr, args->val, val, 821 args->val3); 822 LINUX_CTR3(sys_futex, 823 "WAIT uaddr %p val 0x%x != uval 0x%x", 824 args->uaddr, args->val, val); 825 futex_put(f, wp); 826 827 LIN_SDT_PROBE1(futex, linux_sys_futex, return, 828 EWOULDBLOCK); 829 return (EWOULDBLOCK); 830 } 831 832 error = futex_wait(f, wp, ts, args->val3); 833 break; 834 835 case LINUX_FUTEX_WAKE: 836 args->val3 = FUTEX_BITSET_MATCH_ANY; 837 /* FALLTHROUGH */ 838 839 case LINUX_FUTEX_WAKE_BITSET: 840 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr, 841 args->val, args->val3); 842 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x", 843 args->uaddr, args->val, args->val3); 844 845 error = futex_get(args->uaddr, NULL, &f, 846 flags | FUTEX_DONTCREATE); 847 if (error) { 848 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 849 return (error); 850 } 851 852 if (f == NULL) { 853 td->td_retval[0] = 0; 854 855 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 856 return (error); 857 } 858 td->td_retval[0] = futex_wake(f, args->val, args->val3); 859 futex_put(f, NULL); 860 break; 861 862 case LINUX_FUTEX_CMP_REQUEUE: 863 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue, 864 args->uaddr, args->val, args->val3, args->uaddr2, 865 args->timeout); 866 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p " 867 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x", 868 args->uaddr, args->val, args->val3, args->uaddr2, 869 args->timeout); 870 871 /* 872 * Linux allows this, we would not, it is an incorrect 873 * usage of declared ABI, so return EINVAL. 874 */ 875 if (args->uaddr == args->uaddr2) { 876 LIN_SDT_PROBE0(futex, linux_sys_futex, 877 invalid_cmp_requeue_use); 878 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 879 return (EINVAL); 880 } 881 882 retry1: 883 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK); 884 if (error) { 885 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 886 return (error); 887 } 888 889 /* 890 * To avoid deadlocks return EINVAL if second futex 891 * exists at this time. 892 * 893 * Glibc fall back to FUTEX_WAKE in case of any error 894 * returned by FUTEX_CMP_REQUEUE. 895 */ 896 error = futex_get(args->uaddr2, NULL, &f2, 897 flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK); 898 if (error) { 899 futex_put(f, NULL); 900 901 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 902 return (error); 903 } 904 futex_lock(f); 905 futex_lock(f2); 906 error = copyin_nofault(args->uaddr, &val, sizeof(val)); 907 if (error) { 908 futex_put(f2, NULL); 909 futex_put(f, NULL); 910 error = copyin(args->uaddr, &val, sizeof(val)); 911 if (error == 0) 912 goto retry1; 913 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 914 error); 915 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", 916 error); 917 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 918 return (error); 919 } 920 if (val != args->val3) { 921 LIN_SDT_PROBE2(futex, linux_sys_futex, 922 debug_cmp_requeue_value_neq, args->val, val); 923 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x", 924 args->val, val); 925 futex_put(f2, NULL); 926 futex_put(f, NULL); 927 928 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN); 929 return (EAGAIN); 930 } 931 932 nrwake = (int)(unsigned long)args->timeout; 933 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake); 934 futex_put(f2, NULL); 935 futex_put(f, NULL); 936 break; 937 938 case LINUX_FUTEX_WAKE_OP: 939 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op, 940 args->uaddr, args->op, args->val, args->uaddr2, args->val3); 941 LINUX_CTR5(sys_futex, "WAKE_OP " 942 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x", 943 args->uaddr, args->val, args->uaddr2, args->val3, 944 args->timeout); 945 946 if (args->uaddr == args->uaddr2) { 947 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 948 return (EINVAL); 949 } 950 951 retry2: 952 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK); 953 if (error) { 954 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 955 return (error); 956 } 957 958 error = futex_get(args->uaddr2, NULL, &f2, flags | FUTEX_DONTLOCK); 959 if (error) { 960 futex_put(f, NULL); 961 962 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 963 return (error); 964 } 965 futex_lock(f); 966 futex_lock(f2); 967 968 /* 969 * This function returns positive number as results and 970 * negative as errors 971 */ 972 save = vm_fault_disable_pagefaults(); 973 op_ret = futex_atomic_op(td, args->val3, args->uaddr2); 974 vm_fault_enable_pagefaults(save); 975 976 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x", 977 args->uaddr, op_ret); 978 979 if (op_ret < 0) { 980 if (f2 != NULL) 981 futex_put(f2, NULL); 982 futex_put(f, NULL); 983 error = copyin(args->uaddr2, &val, sizeof(val)); 984 if (error == 0) 985 goto retry2; 986 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 987 return (error); 988 } 989 990 ret = futex_wake(f, args->val, args->val3); 991 992 if (op_ret > 0) { 993 op_ret = 0; 994 nrwake = (int)(unsigned long)args->timeout; 995 996 if (f2 != NULL) 997 op_ret += futex_wake(f2, nrwake, args->val3); 998 else 999 op_ret += futex_wake(f, nrwake, args->val3); 1000 ret += op_ret; 1001 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, 1014 "linux_sys_futex: " 1015 "unsupported futex_pi op\n"); 1016 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1017 LIN_SDT_PROBE0(futex, linux_sys_futex, 1018 unimplemented_lock_pi); 1019 } 1020 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1021 return (ENOSYS); 1022 1023 case LINUX_FUTEX_UNLOCK_PI: 1024 /* not yet implemented */ 1025 pem = pem_find(td->td_proc); 1026 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1027 linux_msg(td, 1028 "linux_sys_futex: " 1029 "unsupported futex_pi op\n"); 1030 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1031 LIN_SDT_PROBE0(futex, linux_sys_futex, 1032 unimplemented_unlock_pi); 1033 } 1034 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1035 return (ENOSYS); 1036 1037 case LINUX_FUTEX_TRYLOCK_PI: 1038 /* not yet implemented */ 1039 pem = pem_find(td->td_proc); 1040 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1041 linux_msg(td, 1042 "linux_sys_futex: " 1043 "unsupported futex_pi op\n"); 1044 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1045 LIN_SDT_PROBE0(futex, linux_sys_futex, 1046 unimplemented_trylock_pi); 1047 } 1048 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1049 return (ENOSYS); 1050 1051 case LINUX_FUTEX_REQUEUE: 1052 /* 1053 * Glibc does not use this operation since version 2.3.3, 1054 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. 1055 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when 1056 * FUTEX_REQUEUE returned EINVAL. 1057 */ 1058 pem = pem_find(td->td_proc); 1059 if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) { 1060 linux_msg(td, 1061 "linux_sys_futex: " 1062 "unsupported futex_requeue op\n"); 1063 pem->flags |= LINUX_XDEPR_REQUEUEOP; 1064 LIN_SDT_PROBE0(futex, linux_sys_futex, 1065 deprecated_requeue); 1066 } 1067 1068 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 1069 return (EINVAL); 1070 1071 case LINUX_FUTEX_WAIT_REQUEUE_PI: 1072 /* not yet implemented */ 1073 pem = pem_find(td->td_proc); 1074 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1075 linux_msg(td, 1076 "linux_sys_futex: " 1077 "unsupported futex_pi op\n"); 1078 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1079 LIN_SDT_PROBE0(futex, linux_sys_futex, 1080 unimplemented_wait_requeue_pi); 1081 } 1082 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1083 return (ENOSYS); 1084 1085 case LINUX_FUTEX_CMP_REQUEUE_PI: 1086 /* not yet implemented */ 1087 pem = pem_find(td->td_proc); 1088 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1089 linux_msg(td, 1090 "linux_sys_futex: " 1091 "unsupported futex_pi op\n"); 1092 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1093 LIN_SDT_PROBE0(futex, linux_sys_futex, 1094 unimplemented_cmp_requeue_pi); 1095 } 1096 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1097 return (ENOSYS); 1098 1099 default: 1100 linux_msg(td, 1101 "linux_sys_futex: unknown op %d\n", args->op); 1102 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation, 1103 args->op); 1104 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1105 return (ENOSYS); 1106 } 1107 1108 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 1109 return (error); 1110 } 1111 1112 int 1113 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) 1114 { 1115 struct linux_emuldata *em; 1116 1117 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args); 1118 1119 if (args->len != sizeof(struct linux_robust_list_head)) { 1120 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error); 1121 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL); 1122 return (EINVAL); 1123 } 1124 1125 em = em_find(td); 1126 em->robust_futexes = args->head; 1127 1128 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0); 1129 return (0); 1130 } 1131 1132 int 1133 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args) 1134 { 1135 struct linux_emuldata *em; 1136 struct linux_robust_list_head *head; 1137 l_size_t len = sizeof(struct linux_robust_list_head); 1138 struct thread *td2; 1139 int error = 0; 1140 1141 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args); 1142 1143 if (!args->pid) { 1144 em = em_find(td); 1145 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1146 head = em->robust_futexes; 1147 } else { 1148 td2 = tdfind(args->pid, -1); 1149 if (td2 == NULL) { 1150 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1151 ESRCH); 1152 return (ESRCH); 1153 } 1154 if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) { 1155 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1156 EPERM); 1157 PROC_UNLOCK(td2->td_proc); 1158 return (EPERM); 1159 } 1160 1161 em = em_find(td2); 1162 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1163 /* XXX: ptrace? */ 1164 if (priv_check(td, PRIV_CRED_SETUID) || 1165 priv_check(td, PRIV_CRED_SETEUID) || 1166 p_candebug(td, td2->td_proc)) { 1167 PROC_UNLOCK(td2->td_proc); 1168 1169 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1170 EPERM); 1171 return (EPERM); 1172 } 1173 head = em->robust_futexes; 1174 1175 PROC_UNLOCK(td2->td_proc); 1176 } 1177 1178 error = copyout(&len, args->len, sizeof(l_size_t)); 1179 if (error) { 1180 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1181 error); 1182 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT); 1183 return (EFAULT); 1184 } 1185 1186 error = copyout(&head, args->head, sizeof(head)); 1187 if (error) { 1188 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1189 error); 1190 } 1191 1192 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error); 1193 return (error); 1194 } 1195 1196 static int 1197 handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr, 1198 unsigned int pi) 1199 { 1200 uint32_t uval, nval, mval; 1201 struct futex *f; 1202 int error; 1203 1204 LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi); 1205 1206 retry: 1207 error = copyin(uaddr, &uval, 4); 1208 if (error) { 1209 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error); 1210 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT); 1211 return (EFAULT); 1212 } 1213 if ((uval & FUTEX_TID_MASK) == em->em_tid) { 1214 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; 1215 nval = casuword32(uaddr, uval, mval); 1216 1217 if (nval == -1) { 1218 LIN_SDT_PROBE1(futex, handle_futex_death, return, 1219 EFAULT); 1220 return (EFAULT); 1221 } 1222 1223 if (nval != uval) 1224 goto retry; 1225 1226 if (!pi && (uval & FUTEX_WAITERS)) { 1227 error = futex_get(uaddr, NULL, &f, 1228 FUTEX_DONTCREATE | FUTEX_SHARED); 1229 if (error) { 1230 LIN_SDT_PROBE1(futex, handle_futex_death, 1231 return, error); 1232 return (error); 1233 } 1234 if (f != NULL) { 1235 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY); 1236 futex_put(f, NULL); 1237 } 1238 } 1239 } 1240 1241 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0); 1242 return (0); 1243 } 1244 1245 static int 1246 fetch_robust_entry(struct linux_robust_list **entry, 1247 struct linux_robust_list **head, unsigned int *pi) 1248 { 1249 l_ulong uentry; 1250 int error; 1251 1252 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi); 1253 1254 error = copyin((const void *)head, &uentry, sizeof(l_ulong)); 1255 if (error) { 1256 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error); 1257 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT); 1258 return (EFAULT); 1259 } 1260 1261 *entry = (void *)(uentry & ~1UL); 1262 *pi = uentry & 1; 1263 1264 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0); 1265 return (0); 1266 } 1267 1268 /* This walks the list of robust futexes releasing them. */ 1269 void 1270 release_futexes(struct thread *td, struct linux_emuldata *em) 1271 { 1272 struct linux_robust_list_head *head = NULL; 1273 struct linux_robust_list *entry, *next_entry, *pending; 1274 unsigned int limit = 2048, pi, next_pi, pip; 1275 l_long futex_offset; 1276 int rc, error; 1277 1278 LIN_SDT_PROBE2(futex, release_futexes, entry, td, em); 1279 1280 head = em->robust_futexes; 1281 1282 if (head == NULL) { 1283 LIN_SDT_PROBE0(futex, release_futexes, return); 1284 return; 1285 } 1286 1287 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) { 1288 LIN_SDT_PROBE0(futex, release_futexes, return); 1289 return; 1290 } 1291 1292 error = copyin(&head->futex_offset, &futex_offset, 1293 sizeof(futex_offset)); 1294 if (error) { 1295 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error); 1296 LIN_SDT_PROBE0(futex, release_futexes, return); 1297 return; 1298 } 1299 1300 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) { 1301 LIN_SDT_PROBE0(futex, release_futexes, return); 1302 return; 1303 } 1304 1305 while (entry != &head->list) { 1306 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); 1307 1308 if (entry != pending) 1309 if (handle_futex_death(em, 1310 (uint32_t *)((caddr_t)entry + futex_offset), pi)) { 1311 LIN_SDT_PROBE0(futex, release_futexes, return); 1312 return; 1313 } 1314 if (rc) { 1315 LIN_SDT_PROBE0(futex, release_futexes, return); 1316 return; 1317 } 1318 1319 entry = next_entry; 1320 pi = next_pi; 1321 1322 if (!--limit) 1323 break; 1324 1325 sched_relinquish(curthread); 1326 } 1327 1328 if (pending) 1329 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip); 1330 1331 LIN_SDT_PROBE0(futex, release_futexes, return); 1332 } 1333