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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: releng/12.0/sys/compat/linux/linux_futex.c 336914 2018-07-30 15:46:40Z asomers $"); 40 #if 0 41 __KERNEL_RCSID(1, "$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 struct futex_list futex_list; 211 212 #define FUTEX_LOCK(f) mtx_lock(&(f)->f_lck) 213 #define FUTEX_LOCKED(f) mtx_owned(&(f)->f_lck) 214 #define FUTEX_UNLOCK(f) mtx_unlock(&(f)->f_lck) 215 #define FUTEX_INIT(f) do { \ 216 mtx_init(&(f)->f_lck, "ftlk", NULL, \ 217 MTX_DUPOK); \ 218 LIN_SDT_PROBE1(futex, futex, create, \ 219 &(f)->f_lck); \ 220 } while (0) 221 #define FUTEX_DESTROY(f) do { \ 222 LIN_SDT_PROBE1(futex, futex, destroy, \ 223 &(f)->f_lck); \ 224 mtx_destroy(&(f)->f_lck); \ 225 } while (0) 226 #define FUTEX_ASSERT_LOCKED(f) mtx_assert(&(f)->f_lck, MA_OWNED) 227 #define FUTEX_ASSERT_UNLOCKED(f) mtx_assert(&(f)->f_lck, MA_NOTOWNED) 228 229 struct mtx futex_mtx; /* protects the futex list */ 230 #define FUTEXES_LOCK do { \ 231 mtx_lock(&futex_mtx); \ 232 LIN_SDT_PROBE1(locks, futex_mtx, \ 233 locked, &futex_mtx); \ 234 } while (0) 235 #define FUTEXES_UNLOCK do { \ 236 LIN_SDT_PROBE1(locks, futex_mtx, \ 237 unlock, &futex_mtx); \ 238 mtx_unlock(&futex_mtx); \ 239 } while (0) 240 241 /* flags for futex_get() */ 242 #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */ 243 #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */ 244 #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */ 245 #define FUTEX_SHARED 0x8 /* shared futex */ 246 #define FUTEX_DONTLOCK 0x10 /* don't lock futex */ 247 248 /* wp_flags */ 249 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list 250 * of futex where thread sleep to wp_list 251 * of another futex. 252 */ 253 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex 254 * wp_list to prevent double wakeup. 255 */ 256 257 static void futex_put(struct futex *, struct waiting_proc *); 258 static int futex_get0(uint32_t *, struct futex **f, uint32_t); 259 static int futex_get(uint32_t *, struct waiting_proc **, struct futex **, 260 uint32_t); 261 static int futex_sleep(struct futex *, struct waiting_proc *, struct timespec *); 262 static int futex_wake(struct futex *, int, uint32_t); 263 static int futex_requeue(struct futex *, int, struct futex *, int); 264 static int futex_copyin_timeout(int, struct l_timespec *, int, 265 struct timespec *); 266 static int futex_wait(struct futex *, struct waiting_proc *, struct timespec *, 267 uint32_t); 268 static void futex_lock(struct futex *); 269 static void futex_unlock(struct futex *); 270 static int futex_atomic_op(struct thread *, int, uint32_t *); 271 static int handle_futex_death(struct linux_emuldata *, uint32_t *, 272 unsigned int); 273 static int fetch_robust_entry(struct linux_robust_list **, 274 struct linux_robust_list **, unsigned int *); 275 276 static int 277 futex_copyin_timeout(int op, struct l_timespec *luts, int clockrt, 278 struct timespec *ts) 279 { 280 struct l_timespec lts; 281 struct timespec kts; 282 int error; 283 284 error = copyin(luts, <s, sizeof(lts)); 285 if (error) 286 return (error); 287 288 error = linux_to_native_timespec(ts, <s); 289 if (error) 290 return (error); 291 if (clockrt) { 292 nanotime(&kts); 293 timespecsub(ts, &kts, ts); 294 } else if (op == LINUX_FUTEX_WAIT_BITSET) { 295 nanouptime(&kts); 296 timespecsub(ts, &kts, ts); 297 } 298 return (error); 299 } 300 301 static void 302 futex_put(struct futex *f, struct waiting_proc *wp) 303 { 304 LIN_SDT_PROBE2(futex, futex_put, entry, f, wp); 305 306 if (wp != NULL) { 307 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0) 308 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 309 free(wp, M_FUTEX_WP); 310 } 311 312 FUTEXES_LOCK; 313 if (--f->f_refcount == 0) { 314 LIST_REMOVE(f, f_list); 315 FUTEXES_UNLOCK; 316 if (FUTEX_LOCKED(f)) 317 futex_unlock(f); 318 319 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr, 320 f->f_refcount, f->f_key.shared); 321 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d " 322 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared); 323 umtx_key_release(&f->f_key); 324 FUTEX_DESTROY(f); 325 free(f, M_FUTEX); 326 327 LIN_SDT_PROBE0(futex, futex_put, return); 328 return; 329 } 330 331 LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount, 332 f->f_key.shared); 333 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d", 334 f->f_uaddr, f->f_refcount, f->f_key.shared); 335 FUTEXES_UNLOCK; 336 if (FUTEX_LOCKED(f)) 337 futex_unlock(f); 338 339 LIN_SDT_PROBE0(futex, futex_put, return); 340 } 341 342 static int 343 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags) 344 { 345 struct futex *f, *tmpf; 346 struct umtx_key key; 347 int error; 348 349 LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags); 350 351 *newf = tmpf = NULL; 352 353 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ? 354 AUTO_SHARE : THREAD_SHARE, &key); 355 if (error) { 356 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error); 357 LIN_SDT_PROBE1(futex, futex_get0, return, error); 358 return (error); 359 } 360 retry: 361 FUTEXES_LOCK; 362 LIST_FOREACH(f, &futex_list, f_list) { 363 if (umtx_key_match(&f->f_key, &key)) { 364 if (tmpf != NULL) { 365 if (FUTEX_LOCKED(tmpf)) 366 futex_unlock(tmpf); 367 FUTEX_DESTROY(tmpf); 368 free(tmpf, M_FUTEX); 369 } 370 if (flags & FUTEX_DONTEXISTS) { 371 FUTEXES_UNLOCK; 372 umtx_key_release(&key); 373 374 LIN_SDT_PROBE1(futex, futex_get0, return, 375 EINVAL); 376 return (EINVAL); 377 } 378 379 /* 380 * Increment refcount of the found futex to 381 * prevent it from deallocation before FUTEX_LOCK() 382 */ 383 ++f->f_refcount; 384 FUTEXES_UNLOCK; 385 umtx_key_release(&key); 386 387 if ((flags & FUTEX_DONTLOCK) == 0) 388 futex_lock(f); 389 *newf = f; 390 LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr, 391 f->f_refcount, f->f_key.shared); 392 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d", 393 uaddr, f->f_refcount, f->f_key.shared); 394 395 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 396 return (0); 397 } 398 } 399 400 if (flags & FUTEX_DONTCREATE) { 401 FUTEXES_UNLOCK; 402 umtx_key_release(&key); 403 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr); 404 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr); 405 406 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 407 return (0); 408 } 409 410 if (tmpf == NULL) { 411 FUTEXES_UNLOCK; 412 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO); 413 tmpf->f_uaddr = uaddr; 414 tmpf->f_key = key; 415 tmpf->f_refcount = 1; 416 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY; 417 FUTEX_INIT(tmpf); 418 TAILQ_INIT(&tmpf->f_waiting_proc); 419 420 /* 421 * Lock the new futex before an insert into the futex_list 422 * to prevent futex usage by other. 423 */ 424 if ((flags & FUTEX_DONTLOCK) == 0) 425 futex_lock(tmpf); 426 goto retry; 427 } 428 429 LIST_INSERT_HEAD(&futex_list, tmpf, f_list); 430 FUTEXES_UNLOCK; 431 432 LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount, 433 tmpf->f_key.shared); 434 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new", 435 uaddr, tmpf->f_refcount, tmpf->f_key.shared); 436 *newf = tmpf; 437 438 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 439 return (0); 440 } 441 442 static int 443 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f, 444 uint32_t flags) 445 { 446 int error; 447 448 LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f); 449 450 if (flags & FUTEX_CREATE_WP) { 451 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK); 452 (*wp)->wp_flags = 0; 453 } 454 error = futex_get0(uaddr, f, flags); 455 if (error) { 456 LIN_SDT_PROBE0(futex, futex_get, error); 457 458 if (flags & FUTEX_CREATE_WP) 459 free(*wp, M_FUTEX_WP); 460 461 LIN_SDT_PROBE1(futex, futex_get, return, error); 462 return (error); 463 } 464 if (flags & FUTEX_CREATE_WP) { 465 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list); 466 (*wp)->wp_futex = *f; 467 } 468 469 LIN_SDT_PROBE1(futex, futex_get, return, error); 470 return (error); 471 } 472 473 static inline void 474 futex_lock(struct futex *f) 475 { 476 477 LINUX_CTR3(sys_futex, "futex_lock uaddr %p ref %d shared %d", 478 f->f_uaddr, f->f_refcount, f->f_key.shared); 479 FUTEX_ASSERT_UNLOCKED(f); 480 FUTEX_LOCK(f); 481 } 482 483 static inline void 484 futex_unlock(struct futex *f) 485 { 486 487 LINUX_CTR3(sys_futex, "futex_unlock uaddr %p ref %d shared %d", 488 f->f_uaddr, f->f_refcount, f->f_key.shared); 489 FUTEX_ASSERT_LOCKED(f); 490 FUTEX_UNLOCK(f); 491 } 492 493 static int 494 futex_sleep(struct futex *f, struct waiting_proc *wp, struct timespec *ts) 495 { 496 struct timespec uts; 497 sbintime_t sbt, prec, tmp; 498 time_t over; 499 int error; 500 501 FUTEX_ASSERT_LOCKED(f); 502 if (ts != NULL) { 503 uts = *ts; 504 if (uts.tv_sec > INT32_MAX / 2) { 505 over = uts.tv_sec - INT32_MAX / 2; 506 uts.tv_sec -= over; 507 } 508 tmp = tstosbt(uts); 509 if (TIMESEL(&sbt, tmp)) 510 sbt += tc_tick_sbt; 511 sbt += tmp; 512 prec = tmp; 513 prec >>= tc_precexp; 514 } else { 515 sbt = 0; 516 prec = 0; 517 } 518 LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, sbt); 519 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %ld ref %d", 520 f->f_uaddr, wp, sbt, f->f_refcount); 521 522 error = msleep_sbt(wp, &f->f_lck, PCATCH, "futex", sbt, prec, C_ABSOLUTE); 523 if (wp->wp_flags & FUTEX_WP_REQUEUED) { 524 KASSERT(f != wp->wp_futex, ("futex != wp_futex")); 525 526 if (error) { 527 LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error, 528 f->f_uaddr, wp, wp->wp_futex->f_uaddr, 529 wp->wp_futex->f_refcount); 530 } 531 532 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp" 533 " %p requeued uaddr %p ref %d", 534 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr, 535 wp->wp_futex->f_refcount); 536 futex_put(f, NULL); 537 f = wp->wp_futex; 538 futex_lock(f); 539 } else { 540 if (error) { 541 LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error, 542 f->f_uaddr, wp); 543 } 544 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p", 545 error, f->f_uaddr, wp); 546 } 547 548 futex_put(f, wp); 549 550 LIN_SDT_PROBE1(futex, futex_sleep, return, error); 551 return (error); 552 } 553 554 static int 555 futex_wake(struct futex *f, int n, uint32_t bitset) 556 { 557 struct waiting_proc *wp, *wpt; 558 int count = 0; 559 560 LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset); 561 562 if (bitset == 0) { 563 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL); 564 return (EINVAL); 565 } 566 567 FUTEX_ASSERT_LOCKED(f); 568 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 569 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp, 570 f->f_refcount); 571 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d", 572 f->f_uaddr, wp, f->f_refcount); 573 /* 574 * Unless we find a matching bit in 575 * the bitset, continue searching. 576 */ 577 if (!(wp->wp_futex->f_bitset & bitset)) 578 continue; 579 580 wp->wp_flags |= FUTEX_WP_REMOVED; 581 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 582 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp); 583 wakeup_one(wp); 584 if (++count == n) 585 break; 586 } 587 588 LIN_SDT_PROBE1(futex, futex_wake, return, count); 589 return (count); 590 } 591 592 static int 593 futex_requeue(struct futex *f, int n, struct futex *f2, int n2) 594 { 595 struct waiting_proc *wp, *wpt; 596 int count = 0; 597 598 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2); 599 600 FUTEX_ASSERT_LOCKED(f); 601 FUTEX_ASSERT_LOCKED(f2); 602 603 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 604 if (++count <= n) { 605 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p", 606 f->f_uaddr, wp); 607 wp->wp_flags |= FUTEX_WP_REMOVED; 608 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 609 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp); 610 wakeup_one(wp); 611 } else { 612 LIN_SDT_PROBE3(futex, futex_requeue, requeue, 613 f->f_uaddr, wp, f2->f_uaddr); 614 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p", 615 f->f_uaddr, wp, f2->f_uaddr); 616 wp->wp_flags |= FUTEX_WP_REQUEUED; 617 /* Move wp to wp_list of f2 futex */ 618 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 619 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list); 620 621 /* 622 * Thread which sleeps on wp after waking should 623 * acquire f2 lock, so increment refcount of f2 to 624 * prevent it from premature deallocation. 625 */ 626 wp->wp_futex = f2; 627 FUTEXES_LOCK; 628 ++f2->f_refcount; 629 FUTEXES_UNLOCK; 630 if (count - n >= n2) 631 break; 632 } 633 } 634 635 LIN_SDT_PROBE1(futex, futex_requeue, return, count); 636 return (count); 637 } 638 639 static int 640 futex_wait(struct futex *f, struct waiting_proc *wp, struct timespec *ts, 641 uint32_t bitset) 642 { 643 int error; 644 645 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, ts, bitset); 646 647 if (bitset == 0) { 648 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL); 649 return (EINVAL); 650 } 651 652 f->f_bitset = bitset; 653 error = futex_sleep(f, wp, ts); 654 if (error) 655 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error); 656 if (error == EWOULDBLOCK) 657 error = ETIMEDOUT; 658 659 LIN_SDT_PROBE1(futex, futex_wait, return, error); 660 return (error); 661 } 662 663 static int 664 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr) 665 { 666 int op = (encoded_op >> 28) & 7; 667 int cmp = (encoded_op >> 24) & 15; 668 int oparg = (encoded_op << 8) >> 20; 669 int cmparg = (encoded_op << 20) >> 20; 670 int oldval = 0, ret; 671 672 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr); 673 674 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 675 oparg = 1 << oparg; 676 677 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg, 678 cmparg); 679 680 /* XXX: Linux verifies access here and returns EFAULT */ 681 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check); 682 683 switch (op) { 684 case FUTEX_OP_SET: 685 ret = futex_xchgl(oparg, uaddr, &oldval); 686 break; 687 case FUTEX_OP_ADD: 688 ret = futex_addl(oparg, uaddr, &oldval); 689 break; 690 case FUTEX_OP_OR: 691 ret = futex_orl(oparg, uaddr, &oldval); 692 break; 693 case FUTEX_OP_ANDN: 694 ret = futex_andl(~oparg, uaddr, &oldval); 695 break; 696 case FUTEX_OP_XOR: 697 ret = futex_xorl(oparg, uaddr, &oldval); 698 break; 699 default: 700 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op); 701 ret = -ENOSYS; 702 break; 703 } 704 705 if (ret) { 706 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 707 return (ret); 708 } 709 710 switch (cmp) { 711 case FUTEX_OP_CMP_EQ: 712 ret = (oldval == cmparg); 713 break; 714 case FUTEX_OP_CMP_NE: 715 ret = (oldval != cmparg); 716 break; 717 case FUTEX_OP_CMP_LT: 718 ret = (oldval < cmparg); 719 break; 720 case FUTEX_OP_CMP_GE: 721 ret = (oldval >= cmparg); 722 break; 723 case FUTEX_OP_CMP_LE: 724 ret = (oldval <= cmparg); 725 break; 726 case FUTEX_OP_CMP_GT: 727 ret = (oldval > cmparg); 728 break; 729 default: 730 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp); 731 ret = -ENOSYS; 732 } 733 734 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 735 return (ret); 736 } 737 738 int 739 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) 740 { 741 int clockrt, nrwake, op_ret, ret; 742 struct linux_pemuldata *pem; 743 struct waiting_proc *wp; 744 struct futex *f, *f2; 745 struct timespec uts, *ts; 746 int error, save; 747 uint32_t flags, val; 748 749 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args); 750 751 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { 752 flags = 0; 753 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG; 754 } else 755 flags = FUTEX_SHARED; 756 757 /* 758 * Currently support for switching between CLOCK_MONOTONIC and 759 * CLOCK_REALTIME is not present. However Linux forbids the use of 760 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and 761 * FUTEX_WAIT_REQUEUE_PI. 762 */ 763 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME; 764 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME; 765 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET && 766 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) { 767 LIN_SDT_PROBE0(futex, linux_sys_futex, 768 unimplemented_clockswitch); 769 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 770 return (ENOSYS); 771 } 772 773 error = 0; 774 f = f2 = NULL; 775 776 switch (args->op) { 777 case LINUX_FUTEX_WAIT: 778 args->val3 = FUTEX_BITSET_MATCH_ANY; 779 /* FALLTHROUGH */ 780 781 case LINUX_FUTEX_WAIT_BITSET: 782 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr, 783 args->val, args->val3); 784 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x", 785 args->uaddr, args->val, args->val3); 786 787 if (args->timeout != NULL) { 788 error = futex_copyin_timeout(args->op, args->timeout, 789 clockrt, &uts); 790 if (error) { 791 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 792 error); 793 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 794 return (error); 795 } 796 ts = &uts; 797 } else 798 ts = NULL; 799 800 retry0: 801 error = futex_get(args->uaddr, &wp, &f, 802 flags | FUTEX_CREATE_WP); 803 if (error) { 804 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 805 return (error); 806 } 807 808 error = copyin_nofault(args->uaddr, &val, sizeof(val)); 809 if (error) { 810 futex_put(f, wp); 811 error = copyin(args->uaddr, &val, sizeof(val)); 812 if (error == 0) 813 goto retry0; 814 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 815 error); 816 LINUX_CTR1(sys_futex, "WAIT copyin failed %d", 817 error); 818 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 819 return (error); 820 } 821 if (val != args->val) { 822 LIN_SDT_PROBE4(futex, linux_sys_futex, 823 debug_wait_value_neq, args->uaddr, args->val, val, 824 args->val3); 825 LINUX_CTR3(sys_futex, 826 "WAIT uaddr %p val 0x%x != uval 0x%x", 827 args->uaddr, args->val, val); 828 futex_put(f, wp); 829 830 LIN_SDT_PROBE1(futex, linux_sys_futex, return, 831 EWOULDBLOCK); 832 return (EWOULDBLOCK); 833 } 834 835 error = futex_wait(f, wp, ts, args->val3); 836 break; 837 838 case LINUX_FUTEX_WAKE: 839 args->val3 = FUTEX_BITSET_MATCH_ANY; 840 /* FALLTHROUGH */ 841 842 case LINUX_FUTEX_WAKE_BITSET: 843 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr, 844 args->val, args->val3); 845 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x", 846 args->uaddr, args->val, args->val3); 847 848 error = futex_get(args->uaddr, NULL, &f, 849 flags | FUTEX_DONTCREATE); 850 if (error) { 851 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 852 return (error); 853 } 854 855 if (f == NULL) { 856 td->td_retval[0] = 0; 857 858 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 859 return (error); 860 } 861 td->td_retval[0] = futex_wake(f, args->val, args->val3); 862 futex_put(f, NULL); 863 break; 864 865 case LINUX_FUTEX_CMP_REQUEUE: 866 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue, 867 args->uaddr, args->val, args->val3, args->uaddr2, 868 args->timeout); 869 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p " 870 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x", 871 args->uaddr, args->val, args->val3, args->uaddr2, 872 args->timeout); 873 874 /* 875 * Linux allows this, we would not, it is an incorrect 876 * usage of declared ABI, so return EINVAL. 877 */ 878 if (args->uaddr == args->uaddr2) { 879 LIN_SDT_PROBE0(futex, linux_sys_futex, 880 invalid_cmp_requeue_use); 881 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 882 return (EINVAL); 883 } 884 885 retry1: 886 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK); 887 if (error) { 888 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 889 return (error); 890 } 891 892 /* 893 * To avoid deadlocks return EINVAL if second futex 894 * exists at this time. 895 * 896 * Glibc fall back to FUTEX_WAKE in case of any error 897 * returned by FUTEX_CMP_REQUEUE. 898 */ 899 error = futex_get(args->uaddr2, NULL, &f2, 900 flags | FUTEX_DONTEXISTS | FUTEX_DONTLOCK); 901 if (error) { 902 futex_put(f, NULL); 903 904 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 905 return (error); 906 } 907 futex_lock(f); 908 futex_lock(f2); 909 error = copyin_nofault(args->uaddr, &val, sizeof(val)); 910 if (error) { 911 futex_put(f2, NULL); 912 futex_put(f, NULL); 913 error = copyin(args->uaddr, &val, sizeof(val)); 914 if (error == 0) 915 goto retry1; 916 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 917 error); 918 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", 919 error); 920 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 921 return (error); 922 } 923 if (val != args->val3) { 924 LIN_SDT_PROBE2(futex, linux_sys_futex, 925 debug_cmp_requeue_value_neq, args->val, val); 926 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x", 927 args->val, val); 928 futex_put(f2, NULL); 929 futex_put(f, NULL); 930 931 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN); 932 return (EAGAIN); 933 } 934 935 nrwake = (int)(unsigned long)args->timeout; 936 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake); 937 futex_put(f2, NULL); 938 futex_put(f, NULL); 939 break; 940 941 case LINUX_FUTEX_WAKE_OP: 942 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op, 943 args->uaddr, args->op, args->val, args->uaddr2, args->val3); 944 LINUX_CTR5(sys_futex, "WAKE_OP " 945 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x", 946 args->uaddr, args->val, args->uaddr2, args->val3, 947 args->timeout); 948 949 if (args->uaddr == args->uaddr2) { 950 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 951 return (EINVAL); 952 } 953 954 retry2: 955 error = futex_get(args->uaddr, NULL, &f, flags | FUTEX_DONTLOCK); 956 if (error) { 957 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 958 return (error); 959 } 960 961 error = futex_get(args->uaddr2, NULL, &f2, flags | FUTEX_DONTLOCK); 962 if (error) { 963 futex_put(f, NULL); 964 965 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 966 return (error); 967 } 968 futex_lock(f); 969 futex_lock(f2); 970 971 /* 972 * This function returns positive number as results and 973 * negative as errors 974 */ 975 save = vm_fault_disable_pagefaults(); 976 op_ret = futex_atomic_op(td, args->val3, args->uaddr2); 977 vm_fault_enable_pagefaults(save); 978 979 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x", 980 args->uaddr, op_ret); 981 982 if (op_ret < 0) { 983 if (f2 != NULL) 984 futex_put(f2, NULL); 985 futex_put(f, NULL); 986 error = copyin(args->uaddr2, &val, sizeof(val)); 987 if (error == 0) 988 goto retry2; 989 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 990 return (error); 991 } 992 993 ret = futex_wake(f, args->val, args->val3); 994 995 if (op_ret > 0) { 996 op_ret = 0; 997 nrwake = (int)(unsigned long)args->timeout; 998 999 if (f2 != NULL) 1000 op_ret += futex_wake(f2, nrwake, args->val3); 1001 else 1002 op_ret += futex_wake(f, nrwake, args->val3); 1003 ret += op_ret; 1004 1005 } 1006 if (f2 != NULL) 1007 futex_put(f2, NULL); 1008 futex_put(f, NULL); 1009 td->td_retval[0] = ret; 1010 break; 1011 1012 case LINUX_FUTEX_LOCK_PI: 1013 /* not yet implemented */ 1014 pem = pem_find(td->td_proc); 1015 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1016 linux_msg(td, 1017 "linux_sys_futex: " 1018 "unsupported futex_pi op\n"); 1019 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1020 LIN_SDT_PROBE0(futex, linux_sys_futex, 1021 unimplemented_lock_pi); 1022 } 1023 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1024 return (ENOSYS); 1025 1026 case LINUX_FUTEX_UNLOCK_PI: 1027 /* not yet implemented */ 1028 pem = pem_find(td->td_proc); 1029 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1030 linux_msg(td, 1031 "linux_sys_futex: " 1032 "unsupported futex_pi op\n"); 1033 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1034 LIN_SDT_PROBE0(futex, linux_sys_futex, 1035 unimplemented_unlock_pi); 1036 } 1037 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1038 return (ENOSYS); 1039 1040 case LINUX_FUTEX_TRYLOCK_PI: 1041 /* not yet implemented */ 1042 pem = pem_find(td->td_proc); 1043 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1044 linux_msg(td, 1045 "linux_sys_futex: " 1046 "unsupported futex_pi op\n"); 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, 1064 "linux_sys_futex: " 1065 "unsupported futex_requeue op\n"); 1066 pem->flags |= LINUX_XDEPR_REQUEUEOP; 1067 LIN_SDT_PROBE0(futex, linux_sys_futex, 1068 deprecated_requeue); 1069 } 1070 1071 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 1072 return (EINVAL); 1073 1074 case LINUX_FUTEX_WAIT_REQUEUE_PI: 1075 /* not yet implemented */ 1076 pem = pem_find(td->td_proc); 1077 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1078 linux_msg(td, 1079 "linux_sys_futex: " 1080 "unsupported futex_pi op\n"); 1081 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1082 LIN_SDT_PROBE0(futex, linux_sys_futex, 1083 unimplemented_wait_requeue_pi); 1084 } 1085 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1086 return (ENOSYS); 1087 1088 case LINUX_FUTEX_CMP_REQUEUE_PI: 1089 /* not yet implemented */ 1090 pem = pem_find(td->td_proc); 1091 if ((pem->flags & LINUX_XUNSUP_FUTEXPIOP) == 0) { 1092 linux_msg(td, 1093 "linux_sys_futex: " 1094 "unsupported futex_pi op\n"); 1095 pem->flags |= LINUX_XUNSUP_FUTEXPIOP; 1096 LIN_SDT_PROBE0(futex, linux_sys_futex, 1097 unimplemented_cmp_requeue_pi); 1098 } 1099 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1100 return (ENOSYS); 1101 1102 default: 1103 linux_msg(td, 1104 "linux_sys_futex: unknown op %d\n", args->op); 1105 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation, 1106 args->op); 1107 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1108 return (ENOSYS); 1109 } 1110 1111 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 1112 return (error); 1113 } 1114 1115 int 1116 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) 1117 { 1118 struct linux_emuldata *em; 1119 1120 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args); 1121 1122 if (args->len != sizeof(struct linux_robust_list_head)) { 1123 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error); 1124 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL); 1125 return (EINVAL); 1126 } 1127 1128 em = em_find(td); 1129 em->robust_futexes = args->head; 1130 1131 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0); 1132 return (0); 1133 } 1134 1135 int 1136 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args) 1137 { 1138 struct linux_emuldata *em; 1139 struct linux_robust_list_head *head; 1140 l_size_t len = sizeof(struct linux_robust_list_head); 1141 struct thread *td2; 1142 int error = 0; 1143 1144 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args); 1145 1146 if (!args->pid) { 1147 em = em_find(td); 1148 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1149 head = em->robust_futexes; 1150 } else { 1151 td2 = tdfind(args->pid, -1); 1152 if (td2 == NULL) { 1153 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1154 ESRCH); 1155 return (ESRCH); 1156 } 1157 if (SV_PROC_ABI(td2->td_proc) != SV_ABI_LINUX) { 1158 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1159 EPERM); 1160 PROC_UNLOCK(td2->td_proc); 1161 return (EPERM); 1162 } 1163 1164 em = em_find(td2); 1165 KASSERT(em != NULL, ("get_robust_list: emuldata notfound.\n")); 1166 /* XXX: ptrace? */ 1167 if (priv_check(td, PRIV_CRED_SETUID) || 1168 priv_check(td, PRIV_CRED_SETEUID) || 1169 p_candebug(td, td2->td_proc)) { 1170 PROC_UNLOCK(td2->td_proc); 1171 1172 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1173 EPERM); 1174 return (EPERM); 1175 } 1176 head = em->robust_futexes; 1177 1178 PROC_UNLOCK(td2->td_proc); 1179 } 1180 1181 error = copyout(&len, args->len, sizeof(l_size_t)); 1182 if (error) { 1183 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1184 error); 1185 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT); 1186 return (EFAULT); 1187 } 1188 1189 error = copyout(&head, args->head, sizeof(head)); 1190 if (error) { 1191 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1192 error); 1193 } 1194 1195 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error); 1196 return (error); 1197 } 1198 1199 static int 1200 handle_futex_death(struct linux_emuldata *em, uint32_t *uaddr, 1201 unsigned int pi) 1202 { 1203 uint32_t uval, nval, mval; 1204 struct futex *f; 1205 int error; 1206 1207 LIN_SDT_PROBE3(futex, handle_futex_death, entry, em, uaddr, pi); 1208 1209 retry: 1210 error = copyin(uaddr, &uval, 4); 1211 if (error) { 1212 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error); 1213 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT); 1214 return (EFAULT); 1215 } 1216 if ((uval & FUTEX_TID_MASK) == em->em_tid) { 1217 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; 1218 nval = casuword32(uaddr, uval, mval); 1219 1220 if (nval == -1) { 1221 LIN_SDT_PROBE1(futex, handle_futex_death, return, 1222 EFAULT); 1223 return (EFAULT); 1224 } 1225 1226 if (nval != uval) 1227 goto retry; 1228 1229 if (!pi && (uval & FUTEX_WAITERS)) { 1230 error = futex_get(uaddr, NULL, &f, 1231 FUTEX_DONTCREATE | FUTEX_SHARED); 1232 if (error) { 1233 LIN_SDT_PROBE1(futex, handle_futex_death, 1234 return, error); 1235 return (error); 1236 } 1237 if (f != NULL) { 1238 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY); 1239 futex_put(f, NULL); 1240 } 1241 } 1242 } 1243 1244 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0); 1245 return (0); 1246 } 1247 1248 static int 1249 fetch_robust_entry(struct linux_robust_list **entry, 1250 struct linux_robust_list **head, unsigned int *pi) 1251 { 1252 l_ulong uentry; 1253 int error; 1254 1255 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi); 1256 1257 error = copyin((const void *)head, &uentry, sizeof(l_ulong)); 1258 if (error) { 1259 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error); 1260 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT); 1261 return (EFAULT); 1262 } 1263 1264 *entry = (void *)(uentry & ~1UL); 1265 *pi = uentry & 1; 1266 1267 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0); 1268 return (0); 1269 } 1270 1271 /* This walks the list of robust futexes releasing them. */ 1272 void 1273 release_futexes(struct thread *td, struct linux_emuldata *em) 1274 { 1275 struct linux_robust_list_head *head = NULL; 1276 struct linux_robust_list *entry, *next_entry, *pending; 1277 unsigned int limit = 2048, pi, next_pi, pip; 1278 l_long futex_offset; 1279 int rc, error; 1280 1281 LIN_SDT_PROBE2(futex, release_futexes, entry, td, em); 1282 1283 head = em->robust_futexes; 1284 1285 if (head == NULL) { 1286 LIN_SDT_PROBE0(futex, release_futexes, return); 1287 return; 1288 } 1289 1290 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) { 1291 LIN_SDT_PROBE0(futex, release_futexes, return); 1292 return; 1293 } 1294 1295 error = copyin(&head->futex_offset, &futex_offset, 1296 sizeof(futex_offset)); 1297 if (error) { 1298 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error); 1299 LIN_SDT_PROBE0(futex, release_futexes, return); 1300 return; 1301 } 1302 1303 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) { 1304 LIN_SDT_PROBE0(futex, release_futexes, return); 1305 return; 1306 } 1307 1308 while (entry != &head->list) { 1309 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); 1310 1311 if (entry != pending) 1312 if (handle_futex_death(em, 1313 (uint32_t *)((caddr_t)entry + futex_offset), pi)) { 1314 LIN_SDT_PROBE0(futex, release_futexes, return); 1315 return; 1316 } 1317 if (rc) { 1318 LIN_SDT_PROBE0(futex, release_futexes, return); 1319 return; 1320 } 1321 1322 entry = next_entry; 1323 pi = next_pi; 1324 1325 if (!--limit) 1326 break; 1327 1328 sched_relinquish(curthread); 1329 } 1330 1331 if (pending) 1332 handle_futex_death(em, (uint32_t *)((caddr_t)pending + futex_offset), pip); 1333 1334 LIN_SDT_PROBE0(futex, release_futexes, return); 1335 }
Cache object: 67a3df6a4a119e6ce0f4101b3988fd72
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