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