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sys/compat/linux/linux_futex.c
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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 nrwake, struct futex *f2, 591 int nrrequeue) 592 { 593 struct waiting_proc *wp, *wpt; 594 int count = 0; 595 596 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, nrwake, f2, nrrequeue); 597 598 FUTEX_ASSERT_LOCKED(f); 599 FUTEX_ASSERT_LOCKED(f2); 600 601 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 602 if (++count <= nrwake) { 603 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p", 604 f->f_uaddr, wp); 605 wp->wp_flags |= FUTEX_WP_REMOVED; 606 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 607 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp); 608 wakeup_one(wp); 609 } else { 610 LIN_SDT_PROBE3(futex, futex_requeue, requeue, 611 f->f_uaddr, wp, f2->f_uaddr); 612 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p", 613 f->f_uaddr, wp, f2->f_uaddr); 614 wp->wp_flags |= FUTEX_WP_REQUEUED; 615 /* Move wp to wp_list of f2 futex */ 616 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 617 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list); 618 619 /* 620 * Thread which sleeps on wp after waking should 621 * acquire f2 lock, so increment refcount of f2 to 622 * prevent it from premature deallocation. 623 */ 624 wp->wp_futex = f2; 625 FUTEXES_LOCK; 626 ++f2->f_refcount; 627 FUTEXES_UNLOCK; 628 if (count - nrwake >= nrrequeue) 629 break; 630 } 631 } 632 633 LIN_SDT_PROBE1(futex, futex_requeue, return, count); 634 return (count); 635 } 636 637 static int 638 futex_wait(struct futex *f, struct waiting_proc *wp, struct timespec *ts, 639 uint32_t bitset) 640 { 641 int error; 642 643 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, ts, bitset); 644 645 if (bitset == 0) { 646 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL); 647 futex_put(f, wp); 648 return (EINVAL); 649 } 650 651 f->f_bitset = bitset; 652 error = futex_sleep(f, wp, ts); 653 if (error) 654 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error); 655 if (error == EWOULDBLOCK) 656 error = ETIMEDOUT; 657 658 LIN_SDT_PROBE1(futex, futex_wait, return, error); 659 return (error); 660 } 661 662 static int 663 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr) 664 { 665 int op = (encoded_op >> 28) & 7; 666 int cmp = (encoded_op >> 24) & 15; 667 int oparg = (encoded_op << 8) >> 20; 668 int cmparg = (encoded_op << 20) >> 20; 669 int oldval = 0, ret; 670 671 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr); 672 673 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 674 oparg = 1 << oparg; 675 676 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg, 677 cmparg); 678 679 /* XXX: Linux verifies access here and returns EFAULT */ 680 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check); 681 682 switch (op) { 683 case FUTEX_OP_SET: 684 ret = futex_xchgl(oparg, uaddr, &oldval); 685 break; 686 case FUTEX_OP_ADD: 687 ret = futex_addl(oparg, uaddr, &oldval); 688 break; 689 case FUTEX_OP_OR: 690 ret = futex_orl(oparg, uaddr, &oldval); 691 break; 692 case FUTEX_OP_ANDN: 693 ret = futex_andl(~oparg, uaddr, &oldval); 694 break; 695 case FUTEX_OP_XOR: 696 ret = futex_xorl(oparg, uaddr, &oldval); 697 break; 698 default: 699 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op); 700 ret = -ENOSYS; 701 break; 702 } 703 704 if (ret) { 705 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 706 return (ret); 707 } 708 709 switch (cmp) { 710 case FUTEX_OP_CMP_EQ: 711 ret = (oldval == cmparg); 712 break; 713 case FUTEX_OP_CMP_NE: 714 ret = (oldval != cmparg); 715 break; 716 case FUTEX_OP_CMP_LT: 717 ret = (oldval < cmparg); 718 break; 719 case FUTEX_OP_CMP_GE: 720 ret = (oldval >= cmparg); 721 break; 722 case FUTEX_OP_CMP_LE: 723 ret = (oldval <= cmparg); 724 break; 725 case FUTEX_OP_CMP_GT: 726 ret = (oldval > cmparg); 727 break; 728 default: 729 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp); 730 ret = -ENOSYS; 731 } 732 733 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 734 return (ret); 735 } 736 737 int 738 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) 739 { 740 int clockrt, nrwake, nrrequeue, op_ret, ret; 741 struct linux_pemuldata *pem; 742 struct waiting_proc *wp; 743 struct futex *f, *f2; 744 struct timespec uts, *ts; 745 int error, save; 746 uint32_t flags, val; 747 748 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args); 749 750 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { 751 flags = 0; 752 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG; 753 } else 754 flags = FUTEX_SHARED; 755 756 /* 757 * Currently support for switching between CLOCK_MONOTONIC and 758 * CLOCK_REALTIME is not present. However Linux forbids the use of 759 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and 760 * FUTEX_WAIT_REQUEUE_PI. 761 */ 762 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME; 763 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME; 764 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET && 765 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) { 766 LIN_SDT_PROBE0(futex, linux_sys_futex, 767 unimplemented_clockswitch); 768 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 769 return (ENOSYS); 770 } 771 772 error = 0; 773 f = f2 = NULL; 774 775 switch (args->op) { 776 case LINUX_FUTEX_WAIT: 777 args->val3 = FUTEX_BITSET_MATCH_ANY; 778 /* FALLTHROUGH */ 779 780 case LINUX_FUTEX_WAIT_BITSET: 781 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr, 782 args->val, args->val3); 783 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x", 784 args->uaddr, args->val, args->val3); 785 786 if (args->timeout != NULL) { 787 error = futex_copyin_timeout(args->op, args->timeout, 788 clockrt, &uts); 789 if (error) { 790 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 791 error); 792 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 793 return (error); 794 } 795 ts = &uts; 796 } else 797 ts = NULL; 798 799 retry0: 800 error = futex_get(args->uaddr, &wp, &f, 801 flags | FUTEX_CREATE_WP); 802 if (error) { 803 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 804 return (error); 805 } 806 807 error = copyin_nofault(args->uaddr, &val, sizeof(val)); 808 if (error) { 809 futex_put(f, wp); 810 error = copyin(args->uaddr, &val, sizeof(val)); 811 if (error == 0) 812 goto retry0; 813 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 814 error); 815 LINUX_CTR1(sys_futex, "WAIT copyin failed %d", 816 error); 817 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 818 return (error); 819 } 820 if (val != args->val) { 821 LIN_SDT_PROBE4(futex, linux_sys_futex, 822 debug_wait_value_neq, args->uaddr, args->val, val, 823 args->val3); 824 LINUX_CTR3(sys_futex, 825 "WAIT uaddr %p val 0x%x != uval 0x%x", 826 args->uaddr, args->val, val); 827 futex_put(f, wp); 828 829 LIN_SDT_PROBE1(futex, linux_sys_futex, return, 830 EWOULDBLOCK); 831 return (EWOULDBLOCK); 832 } 833 834 error = futex_wait(f, wp, ts, args->val3); 835 break; 836 837 case LINUX_FUTEX_WAKE: 838 args->val3 = FUTEX_BITSET_MATCH_ANY; 839 /* FALLTHROUGH */ 840 841 case LINUX_FUTEX_WAKE_BITSET: 842 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr, 843 args->val, args->val3); 844 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x", 845 args->uaddr, args->val, args->val3); 846 847 error = futex_get(args->uaddr, NULL, &f, 848 flags | FUTEX_DONTCREATE); 849 if (error) { 850 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 851 return (error); 852 } 853 854 if (f == NULL) { 855 td->td_retval[0] = 0; 856 857 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 858 return (error); 859 } 860 td->td_retval[0] = futex_wake(f, args->val, args->val3); 861 futex_put(f, NULL); 862 break; 863 864 case LINUX_FUTEX_CMP_REQUEUE: 865 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue, 866 args->uaddr, args->val, args->val3, args->uaddr2, 867 args->timeout); 868 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p " 869 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x", 870 args->uaddr, args->val, args->val3, args->uaddr2, 871 args->timeout); 872 873 /* 874 * Linux allows this, we would not, it is an incorrect 875 * usage of declared ABI, so return EINVAL. 876 */ 877 if (args->uaddr == args->uaddr2) { 878 LIN_SDT_PROBE0(futex, linux_sys_futex, 879 invalid_cmp_requeue_use); 880 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 881 return (EINVAL); 882 } 883 884 nrrequeue = (int)(unsigned long)args->timeout; 885 nrwake = args->val; 886 /* 887 * Sanity check to prevent signed integer overflow, 888 * see Linux CVE-2018-6927 889 */ 890 if (nrwake < 0 || nrrequeue < 0) 891 return (EINVAL); 892 893 retry1: 894 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK); 895 if (error) { 896 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 897 return (error); 898 } 899 900 /* 901 * To avoid deadlocks return EINVAL if second futex 902 * exists at this time. 903 * 904 * Glibc fall back to FUTEX_WAKE in case of any error 905 * returned by FUTEX_CMP_REQUEUE. 906 */ 907 error = futex_get(args->uaddr2, NULL, &f2, 908 flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK); 909 if (error) { 910 futex_put(f, NULL); 911 912 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 913 return (error); 914 } 915 futex_lock(f); 916 futex_lock(f2); 917 error = copyin_nofault(args->uaddr, &val, sizeof(val)); 918 if (error) { 919 futex_put(f2, NULL); 920 futex_put(f, NULL); 921 error = copyin(args->uaddr, &val, sizeof(val)); 922 if (error == 0) 923 goto retry1; 924 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 925 error); 926 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", 927 error); 928 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 929 return (error); 930 } 931 if (val != args->val3) { 932 LIN_SDT_PROBE2(futex, linux_sys_futex, 933 debug_cmp_requeue_value_neq, args->val, val); 934 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x", 935 args->val, val); 936 futex_put(f2, NULL); 937 futex_put(f, NULL); 938 939 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN); 940 return (EAGAIN); 941 } 942 943 td->td_retval[0] = futex_requeue(f, nrwake, f2, nrrequeue); 944 futex_put(f2, NULL); 945 futex_put(f, NULL); 946 break; 947 948 case LINUX_FUTEX_WAKE_OP: 949 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op, 950 args->uaddr, args->op, args->val, args->uaddr2, args->val3); 951 LINUX_CTR5(sys_futex, "WAKE_OP " 952 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x", 953 args->uaddr, args->val, args->uaddr2, args->val3, 954 args->timeout); 955 956 if (args->uaddr == args->uaddr2) { 957 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 958 return (EINVAL); 959 } 960 961 retry2: 962 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK); 963 if (error) { 964 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 965 return (error); 966 } 967 968 error = futex_get(args->uaddr2, NULL, &f2, flags | FUTEX_DONTLOCK); 969 if (error) { 970 futex_put(f, NULL); 971 972 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 973 return (error); 974 } 975 futex_lock(f); 976 futex_lock(f2); 977 978 /* 979 * This function returns positive number as results and 980 * negative as errors 981 */ 982 save = vm_fault_disable_pagefaults(); 983 op_ret = futex_atomic_op(td, args->val3, args->uaddr2); 984 vm_fault_enable_pagefaults(save); 985 986 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x", 987 args->uaddr, op_ret); 988 989 if (op_ret < 0) { 990 if (f2 != NULL) 991 futex_put(f2, NULL); 992 futex_put(f, NULL); 993 error = copyin(args->uaddr2, &val, sizeof(val)); 994 if (error == 0) 995 goto retry2; 996 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 997 return (error); 998 } 999 1000 ret = futex_wake(f, args->val, args->val3); 1001 1002 if (op_ret > 0) { 1003 op_ret = 0; 1004 nrwake = (int)(unsigned long)args->timeout; 1005 1006 if (f2 != NULL) 1007 op_ret += futex_wake(f2, nrwake, args->val3); 1008 else 1009 op_ret += futex_wake(f, nrwake, args->val3); 1010 ret += op_ret; 1011 } 1012 if (f2 != NULL) 1013 futex_put(f2, NULL); 1014 futex_put(f, NULL); 1015 td->td_retval[0] = ret; 1016 break; 1017 1018 case LINUX_FUTEX_LOCK_PI: 1019 /* not yet implemented */ 1020 pem = pem_find(td->td_proc); 1021 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1022 linux_msg(td, "unsupported FUTEX_LOCK_PI"); 1023 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1024 LIN_SDT_PROBE0(futex, linux_sys_futex, 1025 unimplemented_lock_pi); 1026 } 1027 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1028 return (ENOSYS); 1029 1030 case LINUX_FUTEX_UNLOCK_PI: 1031 /* not yet implemented */ 1032 pem = pem_find(td->td_proc); 1033 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1034 linux_msg(td, "unsupported FUTEX_UNLOCK_PI"); 1035 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1036 LIN_SDT_PROBE0(futex, linux_sys_futex, 1037 unimplemented_unlock_pi); 1038 } 1039 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1040 return (ENOSYS); 1041 1042 case LINUX_FUTEX_TRYLOCK_PI: 1043 /* not yet implemented */ 1044 pem = pem_find(td->td_proc); 1045 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1046 linux_msg(td, "unsupported FUTEX_TRYLOCK_PI"); 1047 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1048 LIN_SDT_PROBE0(futex, linux_sys_futex, 1049 unimplemented_trylock_pi); 1050 } 1051 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1052 return (ENOSYS); 1053 1054 case LINUX_FUTEX_REQUEUE: 1055 /* 1056 * Glibc does not use this operation since version 2.3.3, 1057 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. 1058 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when 1059 * FUTEX_REQUEUE returned EINVAL. 1060 */ 1061 pem = pem_find(td->td_proc); 1062 if ((pem->flags & LINUX_XDEPR_REQUEUEOP) == 0) { 1063 linux_msg(td, "unsupported FUTEX_REQUEUE"); 1064 pem->flags |= LINUX_XDEPR_REQUEUEOP; 1065 LIN_SDT_PROBE0(futex, linux_sys_futex, 1066 deprecated_requeue); 1067 } 1068 1069 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 1070 return (EINVAL); 1071 1072 case LINUX_FUTEX_WAIT_REQUEUE_PI: 1073 /* not yet implemented */ 1074 pem = pem_find(td->td_proc); 1075 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1076 linux_msg(td, "unsupported FUTEX_WAIT_REQUEUE_PI"); 1077 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1078 LIN_SDT_PROBE0(futex, linux_sys_futex, 1079 unimplemented_wait_requeue_pi); 1080 } 1081 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1082 return (ENOSYS); 1083 1084 case LINUX_FUTEX_CMP_REQUEUE_PI: 1085 /* not yet implemented */ 1086 pem = pem_find(td->td_proc); 1087 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1088 linux_msg(td, "unsupported FUTEX_CMP_REQUEUE_PI"); 1089 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1090 LIN_SDT_PROBE0(futex, linux_sys_futex, 1091 unimplemented_cmp_requeue_pi); 1092 } 1093 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1094 return (ENOSYS); 1095 1096 default: 1097 linux_msg(td, "unsupported futex op %d", args->op); 1098 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation, 1099 args->op); 1100 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1101 return (ENOSYS); 1102 } 1103 1104 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 1105 return (error); 1106 } 1107 1108 int 1109 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) 1110 { 1111 struct linux_emuldata *em; 1112 1113 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args); 1114 1115 if (args->len != sizeof(struct linux_robust_list_head)) { 1116 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error); 1117 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL); 1118 return (EINVAL); 1119 } 1120 1121 em = em_find(td); 1122 em->robust_futexes = args->head; 1123 1124 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0); 1125 return (0); 1126 } 1127 1128 int 1129 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args) 1130 { 1131 struct linux_emuldata *em; 1132 struct linux_robust_list_head *head; 1133 l_size_t len = sizeof(struct linux_robust_list_head); 1134 struct thread *td2; 1135 int error = 0; 1136 1137 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args); 1138 1139 if (!args->pid) { 1140 em = em_find(td); 1141 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1142 head = em->robust_futexes; 1143 } else { 1144 td2 = tdfind(args->pid, -1); 1145 if (td2 == NULL) { 1146 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1147 ESRCH); 1148 return (ESRCH); 1149 } 1150 if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) { 1151 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1152 EPERM); 1153 PROC_UNLOCK(td2->td_proc); 1154 return (EPERM); 1155 } 1156 1157 em = em_find(td2); 1158 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1159 /* XXX: ptrace? */ 1160 if (priv_check(td, PRIV_CRED_SETUID) || 1161 priv_check(td, PRIV_CRED_SETEUID) || 1162 p_candebug(td, td2->td_proc)) { 1163 PROC_UNLOCK(td2->td_proc); 1164 1165 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1166 EPERM); 1167 return (EPERM); 1168 } 1169 head = em->robust_futexes; 1170 1171 PROC_UNLOCK(td2->td_proc); 1172 } 1173 1174 error = copyout(&len, args->len, sizeof(l_size_t)); 1175 if (error) { 1176 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1177 error); 1178 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT); 1179 return (EFAULT); 1180 } 1181 1182 error = copyout(&head, args->head, sizeof(head)); 1183 if (error) { 1184 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1185 error); 1186 } 1187 1188 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error); 1189 return (error); 1190 } 1191 1192 static int 1193 handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr, 1194 unsigned int pi) 1195 { 1196 uint32_t uval, nval, mval; 1197 struct futex *f; 1198 int error; 1199 1200 LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi); 1201 1202 retry: 1203 error = copyin(uaddr, &uval, 4); 1204 if (error) { 1205 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error); 1206 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT); 1207 return (EFAULT); 1208 } 1209 if ((uval & FUTEX_TID_MASK) == em->em_tid) { 1210 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; 1211 nval = casuword32(uaddr, uval, mval); 1212 1213 if (nval == -1) { 1214 LIN_SDT_PROBE1(futex, handle_futex_death, return, 1215 EFAULT); 1216 return (EFAULT); 1217 } 1218 1219 if (nval != uval) 1220 goto retry; 1221 1222 if (!pi && (uval & FUTEX_WAITERS)) { 1223 error = futex_get(uaddr, NULL, &f, 1224 FUTEX_DONTCREATE | FUTEX_SHARED); 1225 if (error) { 1226 LIN_SDT_PROBE1(futex, handle_futex_death, 1227 return, error); 1228 return (error); 1229 } 1230 if (f != NULL) { 1231 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY); 1232 futex_put(f, NULL); 1233 } 1234 } 1235 } 1236 1237 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0); 1238 return (0); 1239 } 1240 1241 static int 1242 fetch_robust_entry(struct linux_robust_list **entry, 1243 struct linux_robust_list **head, unsigned int *pi) 1244 { 1245 l_ulong uentry; 1246 int error; 1247 1248 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi); 1249 1250 error = copyin((const void *)head, &uentry, sizeof(l_ulong)); 1251 if (error) { 1252 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error); 1253 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT); 1254 return (EFAULT); 1255 } 1256 1257 *entry = (void *)(uentry & ~1UL); 1258 *pi = uentry & 1; 1259 1260 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0); 1261 return (0); 1262 } 1263 1264 /* This walks the list of robust futexes releasing them. */ 1265 void 1266 release_futexes(struct thread *td, struct linux_emuldata *em) 1267 { 1268 struct linux_robust_list_head *head = NULL; 1269 struct linux_robust_list *entry, *next_entry, *pending; 1270 unsigned int limit = 2048, pi, next_pi, pip; 1271 l_long futex_offset; 1272 int rc, error; 1273 1274 LIN_SDT_PROBE2(futex, release_futexes, entry, td, em); 1275 1276 head = em->robust_futexes; 1277 1278 if (head == NULL) { 1279 LIN_SDT_PROBE0(futex, release_futexes, return); 1280 return; 1281 } 1282 1283 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) { 1284 LIN_SDT_PROBE0(futex, release_futexes, return); 1285 return; 1286 } 1287 1288 error = copyin(&head->futex_offset, &futex_offset, 1289 sizeof(futex_offset)); 1290 if (error) { 1291 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error); 1292 LIN_SDT_PROBE0(futex, release_futexes, return); 1293 return; 1294 } 1295 1296 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) { 1297 LIN_SDT_PROBE0(futex, release_futexes, return); 1298 return; 1299 } 1300 1301 while (entry != &head->list) { 1302 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); 1303 1304 if (entry != pending) 1305 if (handle_futex_death(em, 1306 (uint32_t *)((caddr_t)entry + futex_offset), pi)) { 1307 LIN_SDT_PROBE0(futex, release_futexes, return); 1308 return; 1309 } 1310 if (rc) { 1311 LIN_SDT_PROBE0(futex, release_futexes, return); 1312 return; 1313 } 1314 1315 entry = next_entry; 1316 pi = next_pi; 1317 1318 if (!--limit) 1319 break; 1320 1321 sched_relinquish(curthread); 1322 } 1323 1324 if (pending) 1325 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip); 1326 1327 LIN_SDT_PROBE0(futex, release_futexes, return); 1328 }
Cache object: bf6bf0a39e13432524c576d67b8be3a0
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