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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 * 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: releng/10.2/sys/compat/linux/linux_futex.c 293893 2016-01-14 09:10:46Z glebius $"); 36 #if 0 37 __KERNEL_RCSID(1, "$NetBSD: linux_futex.c,v 1.7 2006/07/24 19:01:49 manu Exp $"); 38 #endif 39 40 #include "opt_compat.h" 41 #include "opt_kdtrace.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/imgact.h> 46 #include <sys/kernel.h> 47 #include <sys/ktr.h> 48 #include <sys/lock.h> 49 #include <sys/malloc.h> 50 #include <sys/mutex.h> 51 #include <sys/priv.h> 52 #include <sys/proc.h> 53 #include <sys/queue.h> 54 #include <sys/sched.h> 55 #include <sys/sdt.h> 56 #include <sys/sx.h> 57 #include <sys/umtx.h> 58 59 #ifdef COMPAT_LINUX32 60 #include <machine/../linux32/linux.h> 61 #include <machine/../linux32/linux32_proto.h> 62 #else 63 #include <machine/../linux/linux.h> 64 #include <machine/../linux/linux_proto.h> 65 #endif 66 #include <compat/linux/linux_dtrace.h> 67 #include <compat/linux/linux_emul.h> 68 #include <compat/linux/linux_futex.h> 69 #include <compat/linux/linux_util.h> 70 71 /* DTrace init */ 72 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE); 73 74 /* Linuxulator-global DTrace probes */ 75 LIN_SDT_PROBE_DECLARE(locks, emul_lock, locked); 76 LIN_SDT_PROBE_DECLARE(locks, emul_lock, unlock); 77 78 /** 79 * Futex part for the special DTrace module "locks". 80 */ 81 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, locked, "struct mtx *"); 82 LIN_SDT_PROBE_DEFINE1(locks, futex_mtx, unlock, "struct mtx *"); 83 84 /** 85 * Per futex probes. 86 */ 87 LIN_SDT_PROBE_DEFINE1(futex, futex, create, "struct sx *"); 88 LIN_SDT_PROBE_DEFINE1(futex, futex, destroy, "struct sx *"); 89 90 /** 91 * DTrace probes in this module. 92 */ 93 LIN_SDT_PROBE_DEFINE2(futex, futex_put, entry, "struct futex *", 94 "struct waiting_proc *"); 95 LIN_SDT_PROBE_DEFINE3(futex, futex_put, destroy, "uint32_t *", "uint32_t", 96 "int"); 97 LIN_SDT_PROBE_DEFINE3(futex, futex_put, unlock, "uint32_t *", "uint32_t", 98 "int"); 99 LIN_SDT_PROBE_DEFINE0(futex, futex_put, return); 100 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, entry, "uint32_t *", "struct futex **", 101 "uint32_t"); 102 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, umtx_key_get_error, "int"); 103 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, shared, "uint32_t *", "uint32_t", 104 "int"); 105 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, null, "uint32_t *"); 106 LIN_SDT_PROBE_DEFINE3(futex, futex_get0, new, "uint32_t *", "uint32_t", "int"); 107 LIN_SDT_PROBE_DEFINE1(futex, futex_get0, return, "int"); 108 LIN_SDT_PROBE_DEFINE3(futex, futex_get, entry, "uint32_t *", 109 "struct waiting_proc **", "struct futex **"); 110 LIN_SDT_PROBE_DEFINE0(futex, futex_get, error); 111 LIN_SDT_PROBE_DEFINE1(futex, futex_get, return, "int"); 112 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, entry, "struct futex *", 113 "struct waiting_proc **", "int"); 114 LIN_SDT_PROBE_DEFINE5(futex, futex_sleep, requeue_error, "int", "uint32_t *", 115 "struct waiting_proc *", "uint32_t *", "uint32_t"); 116 LIN_SDT_PROBE_DEFINE3(futex, futex_sleep, sleep_error, "int", "uint32_t *", 117 "struct waiting_proc *"); 118 LIN_SDT_PROBE_DEFINE1(futex, futex_sleep, return, "int"); 119 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, entry, "struct futex *", "int", 120 "uint32_t"); 121 LIN_SDT_PROBE_DEFINE3(futex, futex_wake, iterate, "uint32_t", 122 "struct waiting_proc *", "uint32_t"); 123 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, wakeup, "struct waiting_proc *"); 124 LIN_SDT_PROBE_DEFINE1(futex, futex_wake, return, "int"); 125 LIN_SDT_PROBE_DEFINE4(futex, futex_requeue, entry, "struct futex *", "int", 126 "struct futex *", "int"); 127 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, wakeup, "struct waiting_proc *"); 128 LIN_SDT_PROBE_DEFINE3(futex, futex_requeue, requeue, "uint32_t *", 129 "struct waiting_proc *", "uint32_t"); 130 LIN_SDT_PROBE_DEFINE1(futex, futex_requeue, return, "int"); 131 LIN_SDT_PROBE_DEFINE4(futex, futex_wait, entry, "struct futex *", 132 "struct waiting_proc **", "int", "uint32_t"); 133 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, sleep_error, "int"); 134 LIN_SDT_PROBE_DEFINE1(futex, futex_wait, return, "int"); 135 LIN_SDT_PROBE_DEFINE3(futex, futex_atomic_op, entry, "struct thread *", 136 "int", "uint32_t"); 137 LIN_SDT_PROBE_DEFINE4(futex, futex_atomic_op, decoded_op, "int", "int", "int", 138 "int"); 139 LIN_SDT_PROBE_DEFINE0(futex, futex_atomic_op, missing_access_check); 140 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_op, "int"); 141 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, unimplemented_cmp, "int"); 142 LIN_SDT_PROBE_DEFINE1(futex, futex_atomic_op, return, "int"); 143 LIN_SDT_PROBE_DEFINE2(futex, linux_sys_futex, entry, "struct thread *", 144 "struct linux_sys_futex_args *"); 145 LIN_SDT_PROBE_DEFINE0(futex, linux_sys_futex, unimplemented_clockswitch); 146 LIN_SDT_PROBE_DEFINE1(futex, linux_sys_futex, itimerfix_error, "int"); 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, "struct proc *", 179 "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_DEFINE1(futex, release_futexes, entry, "struct proc *"); 188 LIN_SDT_PROBE_DEFINE1(futex, release_futexes, copyin_error, "int"); 189 LIN_SDT_PROBE_DEFINE0(futex, release_futexes, return); 190 191 static MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes"); 192 static MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futexes wp"); 193 194 struct futex; 195 196 struct waiting_proc { 197 uint32_t wp_flags; 198 struct futex *wp_futex; 199 TAILQ_ENTRY(waiting_proc) wp_list; 200 }; 201 202 struct futex { 203 struct sx f_lck; 204 uint32_t *f_uaddr; /* user-supplied value, for debug */ 205 struct umtx_key f_key; 206 uint32_t f_refcount; 207 uint32_t f_bitset; 208 LIST_ENTRY(futex) f_list; 209 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc; 210 }; 211 212 struct futex_list futex_list; 213 214 #define FUTEX_LOCK(f) sx_xlock(&(f)->f_lck) 215 #define FUTEX_UNLOCK(f) sx_xunlock(&(f)->f_lck) 216 #define FUTEX_INIT(f) do { \ 217 sx_init_flags(&(f)->f_lck, "ftlk", \ 218 SX_DUPOK); \ 219 LIN_SDT_PROBE1(futex, futex, create, \ 220 &(f)->f_lck); \ 221 } while (0) 222 #define FUTEX_DESTROY(f) do { \ 223 LIN_SDT_PROBE1(futex, futex, destroy, \ 224 &(f)->f_lck); \ 225 sx_destroy(&(f)->f_lck); \ 226 } while (0) 227 #define FUTEX_ASSERT_LOCKED(f) sx_assert(&(f)->f_lck, SA_XLOCKED) 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 */ 246 247 /* wp_flags */ 248 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list 249 * of futex where thread sleep to wp_list 250 * of another futex. 251 */ 252 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex 253 * wp_list to prevent double wakeup. 254 */ 255 256 /* support.s */ 257 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval); 258 int futex_addl(int oparg, uint32_t *uaddr, int *oldval); 259 int futex_orl(int oparg, uint32_t *uaddr, int *oldval); 260 int futex_andl(int oparg, uint32_t *uaddr, int *oldval); 261 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval); 262 263 static void 264 futex_put(struct futex *f, struct waiting_proc *wp) 265 { 266 LIN_SDT_PROBE2(futex, futex_put, entry, f, wp); 267 268 FUTEX_ASSERT_LOCKED(f); 269 if (wp != NULL) { 270 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0) 271 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 272 free(wp, M_FUTEX_WP); 273 } 274 275 FUTEXES_LOCK; 276 if (--f->f_refcount == 0) { 277 LIST_REMOVE(f, f_list); 278 FUTEXES_UNLOCK; 279 FUTEX_UNLOCK(f); 280 281 LIN_SDT_PROBE3(futex, futex_put, destroy, f->f_uaddr, 282 f->f_refcount, f->f_key.shared); 283 LINUX_CTR3(sys_futex, "futex_put destroy uaddr %p ref %d " 284 "shared %d", f->f_uaddr, f->f_refcount, f->f_key.shared); 285 umtx_key_release(&f->f_key); 286 FUTEX_DESTROY(f); 287 free(f, M_FUTEX); 288 289 LIN_SDT_PROBE0(futex, futex_put, return); 290 return; 291 } 292 293 LIN_SDT_PROBE3(futex, futex_put, unlock, f->f_uaddr, f->f_refcount, 294 f->f_key.shared); 295 LINUX_CTR3(sys_futex, "futex_put uaddr %p ref %d shared %d", 296 f->f_uaddr, f->f_refcount, f->f_key.shared); 297 FUTEXES_UNLOCK; 298 FUTEX_UNLOCK(f); 299 300 LIN_SDT_PROBE0(futex, futex_put, return); 301 } 302 303 static int 304 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags) 305 { 306 struct futex *f, *tmpf; 307 struct umtx_key key; 308 int error; 309 310 LIN_SDT_PROBE3(futex, futex_get0, entry, uaddr, newf, flags); 311 312 *newf = tmpf = NULL; 313 314 error = umtx_key_get(uaddr, TYPE_FUTEX, (flags & FUTEX_SHARED) ? 315 AUTO_SHARE : THREAD_SHARE, &key); 316 if (error) { 317 LIN_SDT_PROBE1(futex, futex_get0, umtx_key_get_error, error); 318 LIN_SDT_PROBE1(futex, futex_get0, return, error); 319 return (error); 320 } 321 retry: 322 FUTEXES_LOCK; 323 LIST_FOREACH(f, &futex_list, f_list) { 324 if (umtx_key_match(&f->f_key, &key)) { 325 if (tmpf != NULL) { 326 FUTEX_UNLOCK(tmpf); 327 FUTEX_DESTROY(tmpf); 328 free(tmpf, M_FUTEX); 329 } 330 if (flags & FUTEX_DONTEXISTS) { 331 FUTEXES_UNLOCK; 332 umtx_key_release(&key); 333 334 LIN_SDT_PROBE1(futex, futex_get0, return, 335 EINVAL); 336 return (EINVAL); 337 } 338 339 /* 340 * Increment refcount of the found futex to 341 * prevent it from deallocation before FUTEX_LOCK() 342 */ 343 ++f->f_refcount; 344 FUTEXES_UNLOCK; 345 umtx_key_release(&key); 346 347 FUTEX_LOCK(f); 348 *newf = f; 349 LIN_SDT_PROBE3(futex, futex_get0, shared, uaddr, 350 f->f_refcount, f->f_key.shared); 351 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d", 352 uaddr, f->f_refcount, f->f_key.shared); 353 354 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 355 return (0); 356 } 357 } 358 359 if (flags & FUTEX_DONTCREATE) { 360 FUTEXES_UNLOCK; 361 umtx_key_release(&key); 362 LIN_SDT_PROBE1(futex, futex_get0, null, uaddr); 363 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr); 364 365 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 366 return (0); 367 } 368 369 if (tmpf == NULL) { 370 FUTEXES_UNLOCK; 371 tmpf = malloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO); 372 tmpf->f_uaddr = uaddr; 373 tmpf->f_key = key; 374 tmpf->f_refcount = 1; 375 tmpf->f_bitset = FUTEX_BITSET_MATCH_ANY; 376 FUTEX_INIT(tmpf); 377 TAILQ_INIT(&tmpf->f_waiting_proc); 378 379 /* 380 * Lock the new futex before an insert into the futex_list 381 * to prevent futex usage by other. 382 */ 383 FUTEX_LOCK(tmpf); 384 goto retry; 385 } 386 387 LIST_INSERT_HEAD(&futex_list, tmpf, f_list); 388 FUTEXES_UNLOCK; 389 390 LIN_SDT_PROBE3(futex, futex_get0, new, uaddr, tmpf->f_refcount, 391 tmpf->f_key.shared); 392 LINUX_CTR3(sys_futex, "futex_get uaddr %p ref %d shared %d new", 393 uaddr, tmpf->f_refcount, tmpf->f_key.shared); 394 *newf = tmpf; 395 396 LIN_SDT_PROBE1(futex, futex_get0, return, 0); 397 return (0); 398 } 399 400 static int 401 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f, 402 uint32_t flags) 403 { 404 int error; 405 406 LIN_SDT_PROBE3(futex, futex_get, entry, uaddr, wp, f); 407 408 if (flags & FUTEX_CREATE_WP) { 409 *wp = malloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK); 410 (*wp)->wp_flags = 0; 411 } 412 error = futex_get0(uaddr, f, flags); 413 if (error) { 414 LIN_SDT_PROBE0(futex, futex_get, error); 415 416 if (flags & FUTEX_CREATE_WP) 417 free(*wp, M_FUTEX_WP); 418 419 LIN_SDT_PROBE1(futex, futex_get, return, error); 420 return (error); 421 } 422 if (flags & FUTEX_CREATE_WP) { 423 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list); 424 (*wp)->wp_futex = *f; 425 } 426 427 LIN_SDT_PROBE1(futex, futex_get, return, error); 428 return (error); 429 } 430 431 static int 432 futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout) 433 { 434 int error; 435 436 FUTEX_ASSERT_LOCKED(f); 437 LIN_SDT_PROBE3(futex, futex_sleep, entry, f, wp, timeout); 438 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d", 439 f->f_uaddr, wp, timeout, f->f_refcount); 440 error = sx_sleep(wp, &f->f_lck, PCATCH, "futex", timeout); 441 if (wp->wp_flags & FUTEX_WP_REQUEUED) { 442 KASSERT(f != wp->wp_futex, ("futex != wp_futex")); 443 444 if (error) { 445 LIN_SDT_PROBE5(futex, futex_sleep, requeue_error, error, 446 f->f_uaddr, wp, wp->wp_futex->f_uaddr, 447 wp->wp_futex->f_refcount); 448 } 449 450 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p wp" 451 " %p requeued uaddr %p ref %d", 452 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr, 453 wp->wp_futex->f_refcount); 454 futex_put(f, NULL); 455 f = wp->wp_futex; 456 FUTEX_LOCK(f); 457 } else { 458 if (error) { 459 LIN_SDT_PROBE3(futex, futex_sleep, sleep_error, error, 460 f->f_uaddr, wp); 461 } 462 LINUX_CTR3(sys_futex, "futex_sleep out error %d uaddr %p wp %p", 463 error, f->f_uaddr, wp); 464 } 465 466 futex_put(f, wp); 467 468 LIN_SDT_PROBE1(futex, futex_sleep, return, error); 469 return (error); 470 } 471 472 static int 473 futex_wake(struct futex *f, int n, uint32_t bitset) 474 { 475 struct waiting_proc *wp, *wpt; 476 int count = 0; 477 478 LIN_SDT_PROBE3(futex, futex_wake, entry, f, n, bitset); 479 480 if (bitset == 0) { 481 LIN_SDT_PROBE1(futex, futex_wake, return, EINVAL); 482 return (EINVAL); 483 } 484 485 FUTEX_ASSERT_LOCKED(f); 486 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 487 LIN_SDT_PROBE3(futex, futex_wake, iterate, f->f_uaddr, wp, 488 f->f_refcount); 489 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d", 490 f->f_uaddr, wp, f->f_refcount); 491 /* 492 * Unless we find a matching bit in 493 * the bitset, continue searching. 494 */ 495 if (!(wp->wp_futex->f_bitset & bitset)) 496 continue; 497 498 wp->wp_flags |= FUTEX_WP_REMOVED; 499 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 500 LIN_SDT_PROBE1(futex, futex_wake, wakeup, wp); 501 wakeup_one(wp); 502 if (++count == n) 503 break; 504 } 505 506 LIN_SDT_PROBE1(futex, futex_wake, return, count); 507 return (count); 508 } 509 510 static int 511 futex_requeue(struct futex *f, int n, struct futex *f2, int n2) 512 { 513 struct waiting_proc *wp, *wpt; 514 int count = 0; 515 516 LIN_SDT_PROBE4(futex, futex_requeue, entry, f, n, f2, n2); 517 518 FUTEX_ASSERT_LOCKED(f); 519 FUTEX_ASSERT_LOCKED(f2); 520 521 TAILQ_FOREACH_SAFE(wp, &f->f_waiting_proc, wp_list, wpt) { 522 if (++count <= n) { 523 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p", 524 f->f_uaddr, wp); 525 wp->wp_flags |= FUTEX_WP_REMOVED; 526 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 527 LIN_SDT_PROBE1(futex, futex_requeue, wakeup, wp); 528 wakeup_one(wp); 529 } else { 530 LIN_SDT_PROBE3(futex, futex_requeue, requeue, 531 f->f_uaddr, wp, f2->f_uaddr); 532 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p", 533 f->f_uaddr, wp, f2->f_uaddr); 534 wp->wp_flags |= FUTEX_WP_REQUEUED; 535 /* Move wp to wp_list of f2 futex */ 536 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 537 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list); 538 539 /* 540 * Thread which sleeps on wp after waking should 541 * acquire f2 lock, so increment refcount of f2 to 542 * prevent it from premature deallocation. 543 */ 544 wp->wp_futex = f2; 545 FUTEXES_LOCK; 546 ++f2->f_refcount; 547 FUTEXES_UNLOCK; 548 if (count - n >= n2) 549 break; 550 } 551 } 552 553 LIN_SDT_PROBE1(futex, futex_requeue, return, count); 554 return (count); 555 } 556 557 static int 558 futex_wait(struct futex *f, struct waiting_proc *wp, int timeout_hz, 559 uint32_t bitset) 560 { 561 int error; 562 563 LIN_SDT_PROBE4(futex, futex_wait, entry, f, wp, timeout_hz, bitset); 564 565 if (bitset == 0) { 566 LIN_SDT_PROBE1(futex, futex_wait, return, EINVAL); 567 return (EINVAL); 568 } 569 570 f->f_bitset = bitset; 571 error = futex_sleep(f, wp, timeout_hz); 572 if (error) 573 LIN_SDT_PROBE1(futex, futex_wait, sleep_error, error); 574 if (error == EWOULDBLOCK) 575 error = ETIMEDOUT; 576 577 LIN_SDT_PROBE1(futex, futex_wait, return, error); 578 return (error); 579 } 580 581 static int 582 futex_atomic_op(struct thread *td, int encoded_op, uint32_t *uaddr) 583 { 584 int op = (encoded_op >> 28) & 7; 585 int cmp = (encoded_op >> 24) & 15; 586 int oparg = (encoded_op << 8) >> 20; 587 int cmparg = (encoded_op << 20) >> 20; 588 int oldval = 0, ret; 589 590 LIN_SDT_PROBE3(futex, futex_atomic_op, entry, td, encoded_op, uaddr); 591 592 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 593 oparg = 1 << oparg; 594 595 LIN_SDT_PROBE4(futex, futex_atomic_op, decoded_op, op, cmp, oparg, 596 cmparg); 597 598 /* XXX: Linux verifies access here and returns EFAULT */ 599 LIN_SDT_PROBE0(futex, futex_atomic_op, missing_access_check); 600 601 switch (op) { 602 case FUTEX_OP_SET: 603 ret = futex_xchgl(oparg, uaddr, &oldval); 604 break; 605 case FUTEX_OP_ADD: 606 ret = futex_addl(oparg, uaddr, &oldval); 607 break; 608 case FUTEX_OP_OR: 609 ret = futex_orl(oparg, uaddr, &oldval); 610 break; 611 case FUTEX_OP_ANDN: 612 ret = futex_andl(~oparg, uaddr, &oldval); 613 break; 614 case FUTEX_OP_XOR: 615 ret = futex_xorl(oparg, uaddr, &oldval); 616 break; 617 default: 618 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_op, op); 619 ret = -ENOSYS; 620 break; 621 } 622 623 if (ret) { 624 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 625 return (ret); 626 } 627 628 switch (cmp) { 629 case FUTEX_OP_CMP_EQ: 630 ret = (oldval == cmparg); 631 break; 632 case FUTEX_OP_CMP_NE: 633 ret = (oldval != cmparg); 634 break; 635 case FUTEX_OP_CMP_LT: 636 ret = (oldval < cmparg); 637 break; 638 case FUTEX_OP_CMP_GE: 639 ret = (oldval >= cmparg); 640 break; 641 case FUTEX_OP_CMP_LE: 642 ret = (oldval <= cmparg); 643 break; 644 case FUTEX_OP_CMP_GT: 645 ret = (oldval > cmparg); 646 break; 647 default: 648 LIN_SDT_PROBE1(futex, futex_atomic_op, unimplemented_cmp, cmp); 649 ret = -ENOSYS; 650 } 651 652 LIN_SDT_PROBE1(futex, futex_atomic_op, return, ret); 653 return (ret); 654 } 655 656 int 657 linux_sys_futex(struct thread *td, struct linux_sys_futex_args *args) 658 { 659 int clockrt, nrwake, op_ret, ret; 660 struct linux_emuldata *em; 661 struct waiting_proc *wp; 662 struct futex *f, *f2; 663 struct l_timespec timeout; 664 struct timeval utv, ctv; 665 int timeout_hz; 666 int error; 667 uint32_t flags, val; 668 669 LIN_SDT_PROBE2(futex, linux_sys_futex, entry, td, args); 670 671 if (args->op & LINUX_FUTEX_PRIVATE_FLAG) { 672 flags = 0; 673 args->op &= ~LINUX_FUTEX_PRIVATE_FLAG; 674 } else 675 flags = FUTEX_SHARED; 676 677 /* 678 * Currently support for switching between CLOCK_MONOTONIC and 679 * CLOCK_REALTIME is not present. However Linux forbids the use of 680 * FUTEX_CLOCK_REALTIME with any op except FUTEX_WAIT_BITSET and 681 * FUTEX_WAIT_REQUEUE_PI. 682 */ 683 clockrt = args->op & LINUX_FUTEX_CLOCK_REALTIME; 684 args->op = args->op & ~LINUX_FUTEX_CLOCK_REALTIME; 685 if (clockrt && args->op != LINUX_FUTEX_WAIT_BITSET && 686 args->op != LINUX_FUTEX_WAIT_REQUEUE_PI) { 687 LIN_SDT_PROBE0(futex, linux_sys_futex, 688 unimplemented_clockswitch); 689 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 690 return (ENOSYS); 691 } 692 693 error = 0; 694 f = f2 = NULL; 695 696 switch (args->op) { 697 case LINUX_FUTEX_WAIT: 698 args->val3 = FUTEX_BITSET_MATCH_ANY; 699 /* FALLTHROUGH */ 700 701 case LINUX_FUTEX_WAIT_BITSET: 702 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wait, args->uaddr, 703 args->val, args->val3); 704 LINUX_CTR3(sys_futex, "WAIT uaddr %p val 0x%x bitset 0x%x", 705 args->uaddr, args->val, args->val3); 706 707 error = futex_get(args->uaddr, &wp, &f, 708 flags | FUTEX_CREATE_WP); 709 if (error) { 710 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 711 return (error); 712 } 713 714 error = copyin(args->uaddr, &val, sizeof(val)); 715 if (error) { 716 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 717 error); 718 LINUX_CTR1(sys_futex, "WAIT copyin failed %d", 719 error); 720 futex_put(f, wp); 721 722 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 723 return (error); 724 } 725 if (val != args->val) { 726 LIN_SDT_PROBE4(futex, linux_sys_futex, 727 debug_wait_value_neq, args->uaddr, args->val, val, 728 args->val3); 729 LINUX_CTR3(sys_futex, 730 "WAIT uaddr %p val 0x%x != uval 0x%x", 731 args->uaddr, args->val, val); 732 futex_put(f, wp); 733 734 LIN_SDT_PROBE1(futex, linux_sys_futex, return, 735 EWOULDBLOCK); 736 return (EWOULDBLOCK); 737 } 738 739 if (args->timeout != NULL) { 740 error = copyin(args->timeout, &timeout, sizeof(timeout)); 741 if (error) { 742 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 743 error); 744 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 745 futex_put(f, wp); 746 return (error); 747 } 748 TIMESPEC_TO_TIMEVAL(&utv, &timeout); 749 error = itimerfix(&utv); 750 if (error) { 751 LIN_SDT_PROBE1(futex, linux_sys_futex, itimerfix_error, 752 error); 753 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 754 futex_put(f, wp); 755 return (error); 756 } 757 if (clockrt) { 758 microtime(&ctv); 759 timevalsub(&utv, &ctv); 760 } else if (args->op == LINUX_FUTEX_WAIT_BITSET) { 761 microuptime(&ctv); 762 timevalsub(&utv, &ctv); 763 } 764 if (utv.tv_sec < 0) 765 timevalclear(&utv); 766 timeout_hz = tvtohz(&utv); 767 } else 768 timeout_hz = 0; 769 770 error = futex_wait(f, wp, timeout_hz, args->val3); 771 break; 772 773 case LINUX_FUTEX_WAKE: 774 args->val3 = FUTEX_BITSET_MATCH_ANY; 775 /* FALLTHROUGH */ 776 777 case LINUX_FUTEX_WAKE_BITSET: 778 LIN_SDT_PROBE3(futex, linux_sys_futex, debug_wake, args->uaddr, 779 args->val, args->val3); 780 LINUX_CTR3(sys_futex, "WAKE uaddr %p nrwake 0x%x bitset 0x%x", 781 args->uaddr, args->val, args->val3); 782 783 error = futex_get(args->uaddr, NULL, &f, 784 flags | FUTEX_DONTCREATE); 785 if (error) { 786 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 787 return (error); 788 } 789 790 if (f == NULL) { 791 td->td_retval[0] = 0; 792 793 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 794 return (error); 795 } 796 td->td_retval[0] = futex_wake(f, args->val, args->val3); 797 futex_put(f, NULL); 798 break; 799 800 case LINUX_FUTEX_CMP_REQUEUE: 801 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_cmp_requeue, 802 args->uaddr, args->val, args->val3, args->uaddr2, 803 args->timeout); 804 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p " 805 "nrwake 0x%x uval 0x%x uaddr2 %p nrequeue 0x%x", 806 args->uaddr, args->val, args->val3, args->uaddr2, 807 args->timeout); 808 809 /* 810 * Linux allows this, we would not, it is an incorrect 811 * usage of declared ABI, so return EINVAL. 812 */ 813 if (args->uaddr == args->uaddr2) { 814 LIN_SDT_PROBE0(futex, linux_sys_futex, 815 invalid_cmp_requeue_use); 816 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 817 return (EINVAL); 818 } 819 820 error = futex_get(args->uaddr, NULL, &f, flags); 821 if (error) { 822 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 823 return (error); 824 } 825 826 /* 827 * To avoid deadlocks return EINVAL if second futex 828 * exists at this time. 829 * 830 * Glibc fall back to FUTEX_WAKE in case of any error 831 * returned by FUTEX_CMP_REQUEUE. 832 */ 833 error = futex_get(args->uaddr2, NULL, &f2, 834 flags | FUTEX_DONTEXISTS); 835 if (error) { 836 futex_put(f, NULL); 837 838 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 839 return (error); 840 } 841 error = copyin(args->uaddr, &val, sizeof(val)); 842 if (error) { 843 LIN_SDT_PROBE1(futex, linux_sys_futex, copyin_error, 844 error); 845 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", 846 error); 847 futex_put(f2, NULL); 848 futex_put(f, NULL); 849 850 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 851 return (error); 852 } 853 if (val != args->val3) { 854 LIN_SDT_PROBE2(futex, linux_sys_futex, 855 debug_cmp_requeue_value_neq, args->val, val); 856 LINUX_CTR2(sys_futex, "CMP_REQUEUE val 0x%x != uval 0x%x", 857 args->val, val); 858 futex_put(f2, NULL); 859 futex_put(f, NULL); 860 861 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EAGAIN); 862 return (EAGAIN); 863 } 864 865 nrwake = (int)(unsigned long)args->timeout; 866 td->td_retval[0] = futex_requeue(f, args->val, f2, nrwake); 867 futex_put(f2, NULL); 868 futex_put(f, NULL); 869 break; 870 871 case LINUX_FUTEX_WAKE_OP: 872 LIN_SDT_PROBE5(futex, linux_sys_futex, debug_wake_op, 873 args->uaddr, args->op, args->val, args->uaddr2, args->val3); 874 LINUX_CTR5(sys_futex, "WAKE_OP " 875 "uaddr %p nrwake 0x%x uaddr2 %p op 0x%x nrwake2 0x%x", 876 args->uaddr, args->val, args->uaddr2, args->val3, 877 args->timeout); 878 879 error = futex_get(args->uaddr, NULL, &f, flags); 880 if (error) { 881 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 882 return (error); 883 } 884 885 if (args->uaddr != args->uaddr2) 886 error = futex_get(args->uaddr2, NULL, &f2, flags); 887 if (error) { 888 futex_put(f, NULL); 889 890 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 891 return (error); 892 } 893 894 /* 895 * This function returns positive number as results and 896 * negative as errors 897 */ 898 op_ret = futex_atomic_op(td, args->val3, args->uaddr2); 899 900 LINUX_CTR2(sys_futex, "WAKE_OP atomic_op uaddr %p ret 0x%x", 901 args->uaddr, op_ret); 902 903 if (op_ret < 0) { 904 /* XXX: We don't handle the EFAULT yet. */ 905 if (op_ret != -EFAULT) { 906 if (f2 != NULL) 907 futex_put(f2, NULL); 908 futex_put(f, NULL); 909 910 LIN_SDT_PROBE1(futex, linux_sys_futex, return, 911 -op_ret); 912 return (-op_ret); 913 } else { 914 LIN_SDT_PROBE0(futex, linux_sys_futex, 915 unhandled_efault); 916 } 917 if (f2 != NULL) 918 futex_put(f2, NULL); 919 futex_put(f, NULL); 920 921 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EFAULT); 922 return (EFAULT); 923 } 924 925 ret = futex_wake(f, args->val, args->val3); 926 927 if (op_ret > 0) { 928 op_ret = 0; 929 nrwake = (int)(unsigned long)args->timeout; 930 931 if (f2 != NULL) 932 op_ret += futex_wake(f2, nrwake, args->val3); 933 else 934 op_ret += futex_wake(f, nrwake, args->val3); 935 ret += op_ret; 936 937 } 938 if (f2 != NULL) 939 futex_put(f2, NULL); 940 futex_put(f, NULL); 941 td->td_retval[0] = ret; 942 break; 943 944 case LINUX_FUTEX_LOCK_PI: 945 /* not yet implemented */ 946 linux_msg(td, 947 "linux_sys_futex: " 948 "op LINUX_FUTEX_LOCK_PI not implemented\n"); 949 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_lock_pi); 950 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 951 return (ENOSYS); 952 953 case LINUX_FUTEX_UNLOCK_PI: 954 /* not yet implemented */ 955 linux_msg(td, 956 "linux_sys_futex: " 957 "op LINUX_FUTEX_UNLOCK_PI not implemented\n"); 958 LIN_SDT_PROBE0(futex, linux_sys_futex, unimplemented_unlock_pi); 959 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 960 return (ENOSYS); 961 962 case LINUX_FUTEX_TRYLOCK_PI: 963 /* not yet implemented */ 964 linux_msg(td, 965 "linux_sys_futex: " 966 "op LINUX_FUTEX_TRYLOCK_PI not implemented\n"); 967 LIN_SDT_PROBE0(futex, linux_sys_futex, 968 unimplemented_trylock_pi); 969 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 970 return (ENOSYS); 971 972 case LINUX_FUTEX_REQUEUE: 973 974 /* 975 * Glibc does not use this operation since version 2.3.3, 976 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. 977 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when 978 * FUTEX_REQUEUE returned EINVAL. 979 */ 980 em = em_find(td->td_proc, EMUL_DONTLOCK); 981 if ((em->flags & LINUX_XDEPR_REQUEUEOP) == 0) { 982 linux_msg(td, 983 "linux_sys_futex: " 984 "unsupported futex_requeue op\n"); 985 em->flags |= LINUX_XDEPR_REQUEUEOP; 986 LIN_SDT_PROBE0(futex, linux_sys_futex, 987 deprecated_requeue); 988 } 989 990 LIN_SDT_PROBE1(futex, linux_sys_futex, return, EINVAL); 991 return (EINVAL); 992 993 case LINUX_FUTEX_WAIT_REQUEUE_PI: 994 /* not yet implemented */ 995 linux_msg(td, 996 "linux_sys_futex: " 997 "op FUTEX_WAIT_REQUEUE_PI not implemented\n"); 998 LIN_SDT_PROBE0(futex, linux_sys_futex, 999 unimplemented_wait_requeue_pi); 1000 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1001 return (ENOSYS); 1002 1003 case LINUX_FUTEX_CMP_REQUEUE_PI: 1004 /* not yet implemented */ 1005 linux_msg(td, 1006 "linux_sys_futex: " 1007 "op LINUX_FUTEX_CMP_REQUEUE_PI not implemented\n"); 1008 LIN_SDT_PROBE0(futex, linux_sys_futex, 1009 unimplemented_cmp_requeue_pi); 1010 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1011 return (ENOSYS); 1012 1013 default: 1014 linux_msg(td, 1015 "linux_sys_futex: unknown op %d\n", args->op); 1016 LIN_SDT_PROBE1(futex, linux_sys_futex, unknown_operation, 1017 args->op); 1018 LIN_SDT_PROBE1(futex, linux_sys_futex, return, ENOSYS); 1019 return (ENOSYS); 1020 } 1021 1022 LIN_SDT_PROBE1(futex, linux_sys_futex, return, error); 1023 return (error); 1024 } 1025 1026 int 1027 linux_set_robust_list(struct thread *td, struct linux_set_robust_list_args *args) 1028 { 1029 struct linux_emuldata *em; 1030 1031 LIN_SDT_PROBE2(futex, linux_set_robust_list, entry, td, args); 1032 1033 if (args->len != sizeof(struct linux_robust_list_head)) { 1034 LIN_SDT_PROBE0(futex, linux_set_robust_list, size_error); 1035 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, EINVAL); 1036 return (EINVAL); 1037 } 1038 1039 em = em_find(td->td_proc, EMUL_DOLOCK); 1040 em->robust_futexes = args->head; 1041 EMUL_UNLOCK(&emul_lock); 1042 1043 LIN_SDT_PROBE1(futex, linux_set_robust_list, return, 0); 1044 return (0); 1045 } 1046 1047 int 1048 linux_get_robust_list(struct thread *td, struct linux_get_robust_list_args *args) 1049 { 1050 struct linux_emuldata *em; 1051 struct linux_robust_list_head *head; 1052 l_size_t len = sizeof(struct linux_robust_list_head); 1053 int error = 0; 1054 1055 LIN_SDT_PROBE2(futex, linux_get_robust_list, entry, td, args); 1056 1057 if (!args->pid) { 1058 em = em_find(td->td_proc, EMUL_DONTLOCK); 1059 head = em->robust_futexes; 1060 } else { 1061 struct proc *p; 1062 1063 p = pfind(args->pid); 1064 if (p == NULL) { 1065 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1066 ESRCH); 1067 return (ESRCH); 1068 } 1069 1070 em = em_find(p, EMUL_DONTLOCK); 1071 /* XXX: ptrace? */ 1072 if (priv_check(td, PRIV_CRED_SETUID) || 1073 priv_check(td, PRIV_CRED_SETEUID) || 1074 p_candebug(td, p)) { 1075 PROC_UNLOCK(p); 1076 1077 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, 1078 EPERM); 1079 return (EPERM); 1080 } 1081 head = em->robust_futexes; 1082 1083 PROC_UNLOCK(p); 1084 } 1085 1086 error = copyout(&len, args->len, sizeof(l_size_t)); 1087 if (error) { 1088 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1089 error); 1090 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, EFAULT); 1091 return (EFAULT); 1092 } 1093 1094 error = copyout(&head, args->head, sizeof(head)); 1095 if (error) { 1096 LIN_SDT_PROBE1(futex, linux_get_robust_list, copyout_error, 1097 error); 1098 } 1099 1100 LIN_SDT_PROBE1(futex, linux_get_robust_list, return, error); 1101 return (error); 1102 } 1103 1104 static int 1105 handle_futex_death(struct proc *p, uint32_t *uaddr, unsigned int pi) 1106 { 1107 uint32_t uval, nval, mval; 1108 struct futex *f; 1109 int error; 1110 1111 LIN_SDT_PROBE3(futex, handle_futex_death, entry, p, uaddr, pi); 1112 1113 retry: 1114 error = copyin(uaddr, &uval, 4); 1115 if (error) { 1116 LIN_SDT_PROBE1(futex, handle_futex_death, copyin_error, error); 1117 LIN_SDT_PROBE1(futex, handle_futex_death, return, EFAULT); 1118 return (EFAULT); 1119 } 1120 if ((uval & FUTEX_TID_MASK) == p->p_pid) { 1121 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; 1122 nval = casuword32(uaddr, uval, mval); 1123 1124 if (nval == -1) { 1125 LIN_SDT_PROBE1(futex, handle_futex_death, return, 1126 EFAULT); 1127 return (EFAULT); 1128 } 1129 1130 if (nval != uval) 1131 goto retry; 1132 1133 if (!pi && (uval & FUTEX_WAITERS)) { 1134 error = futex_get(uaddr, NULL, &f, 1135 FUTEX_DONTCREATE | FUTEX_SHARED); 1136 if (error) { 1137 LIN_SDT_PROBE1(futex, handle_futex_death, 1138 return, error); 1139 return (error); 1140 } 1141 if (f != NULL) { 1142 futex_wake(f, 1, FUTEX_BITSET_MATCH_ANY); 1143 futex_put(f, NULL); 1144 } 1145 } 1146 } 1147 1148 LIN_SDT_PROBE1(futex, handle_futex_death, return, 0); 1149 return (0); 1150 } 1151 1152 static int 1153 fetch_robust_entry(struct linux_robust_list **entry, 1154 struct linux_robust_list **head, unsigned int *pi) 1155 { 1156 l_ulong uentry; 1157 int error; 1158 1159 LIN_SDT_PROBE3(futex, fetch_robust_entry, entry, entry, head, pi); 1160 1161 error = copyin((const void *)head, &uentry, sizeof(l_ulong)); 1162 if (error) { 1163 LIN_SDT_PROBE1(futex, fetch_robust_entry, copyin_error, error); 1164 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, EFAULT); 1165 return (EFAULT); 1166 } 1167 1168 *entry = (void *)(uentry & ~1UL); 1169 *pi = uentry & 1; 1170 1171 LIN_SDT_PROBE1(futex, fetch_robust_entry, return, 0); 1172 return (0); 1173 } 1174 1175 /* This walks the list of robust futexes releasing them. */ 1176 void 1177 release_futexes(struct proc *p) 1178 { 1179 struct linux_robust_list_head *head = NULL; 1180 struct linux_robust_list *entry, *next_entry, *pending; 1181 unsigned int limit = 2048, pi, next_pi, pip; 1182 struct linux_emuldata *em; 1183 l_long futex_offset; 1184 int rc, error; 1185 1186 LIN_SDT_PROBE1(futex, release_futexes, entry, p); 1187 1188 em = em_find(p, EMUL_DONTLOCK); 1189 head = em->robust_futexes; 1190 1191 if (head == NULL) { 1192 LIN_SDT_PROBE0(futex, release_futexes, return); 1193 return; 1194 } 1195 1196 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) { 1197 LIN_SDT_PROBE0(futex, release_futexes, return); 1198 return; 1199 } 1200 1201 error = copyin(&head->futex_offset, &futex_offset, 1202 sizeof(futex_offset)); 1203 if (error) { 1204 LIN_SDT_PROBE1(futex, release_futexes, copyin_error, error); 1205 LIN_SDT_PROBE0(futex, release_futexes, return); 1206 return; 1207 } 1208 1209 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) { 1210 LIN_SDT_PROBE0(futex, release_futexes, return); 1211 return; 1212 } 1213 1214 while (entry != &head->list) { 1215 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); 1216 1217 if (entry != pending) 1218 if (handle_futex_death(p, 1219 (uint32_t *)((caddr_t)entry + futex_offset), pi)) { 1220 LIN_SDT_PROBE0(futex, release_futexes, return); 1221 return; 1222 } 1223 if (rc) { 1224 LIN_SDT_PROBE0(futex, release_futexes, return); 1225 return; 1226 } 1227 1228 entry = next_entry; 1229 pi = next_pi; 1230 1231 if (!--limit) 1232 break; 1233 1234 sched_relinquish(curthread); 1235 } 1236 1237 if (pending) 1238 handle_futex_death(p, (uint32_t *)((caddr_t)pending + futex_offset), pip); 1239 1240 LIN_SDT_PROBE0(futex, release_futexes, return); 1241 }
Cache object: cd785ee85f3da8da5354ae9eb934672c
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