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sys/emulation/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 "opt_compat.h" 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/imgact.h> 39 #include <sys/imgact_aout.h> 40 #include <sys/imgact_elf.h> 41 #include <sys/kern_syscall.h> 42 #include <sys/lock.h> 43 #include <sys/malloc.h> 44 #include <sys/proc.h> 45 #include <sys/signalvar.h> 46 #include <sys/sysent.h> 47 #include <sys/sysproto.h> 48 #include <sys/priv.h> 49 #include <sys/lock.h> 50 #include <sys/spinlock2.h> 51 52 #include <vm/vm.h> 53 #include <vm/vm_param.h> 54 #include <vm/vm_page.h> 55 #include <vm/vm_extern.h> 56 #include <sys/exec.h> 57 #include <sys/kernel.h> 58 #include <sys/module.h> 59 #include <machine/cpu.h> 60 #include <machine/limits.h> 61 62 #include "i386/linux.h" 63 #include "i386/linux_proto.h" 64 #include "linux_signal.h" 65 #include "linux_util.h" 66 #include "linux_emuldata.h" 67 68 MALLOC_DEFINE(M_FUTEX, "futex", "Linux futexes"); 69 MALLOC_DEFINE(M_FUTEX_WP, "futex wp", "Linux futexes wp"); 70 71 struct futex; 72 73 struct waiting_proc { 74 uint32_t wp_flags; 75 struct futex *wp_futex; 76 TAILQ_ENTRY(waiting_proc) wp_list; 77 }; 78 79 struct futex { 80 struct lock f_lck; 81 uint32_t *f_uaddr; 82 uint32_t f_refcount; 83 LIST_ENTRY(futex) f_list; 84 TAILQ_HEAD(lf_waiting_proc, waiting_proc) f_waiting_proc; 85 }; 86 87 struct futex_list futex_list; 88 89 #if 0 90 #define FUTEX_LOCK(f) spin_lock(&(f)->f_lck) 91 #define FUTEX_UNLOCK(f) spin_unlock(&(f)->f_lck) 92 #define FUTEX_INIT(f) spin_init(&(f)->f_lck) 93 #define FUTEX_SLEEP(f, id, flag, wm, timo) ssleep((id), &(f)->f_lck, (flag), (wm), (timo)) 94 #endif 95 96 #define FUTEX_LOCK(f) lockmgr(&(f)->f_lck, LK_EXCLUSIVE) 97 #define FUTEX_UNLOCK(f) lockmgr(&(f)->f_lck, LK_RELEASE) 98 #define FUTEX_INIT(f) lockinit(&(f)->f_lck, "ftlk", 0, LK_CANRECURSE) 99 #define FUTEX_DESTROY(f) lockuninit(&(f)->f_lck) 100 #define FUTEX_ASSERT_LOCKED(f) KKASSERT(lockstatus(&(f)->f_lck, curthread) == LK_EXCLUSIVE) 101 #define FUTEX_SLEEP(f, id, flag, wm, timo) lksleep((id), &(f)->f_lck, (flag), (wm), (timo)) 102 103 struct lock futex_mtx; /* protects the futex list */ 104 #define FUTEXES_LOCK lockmgr(&futex_mtx, LK_EXCLUSIVE) 105 #define FUTEXES_UNLOCK lockmgr(&futex_mtx, LK_RELEASE) 106 107 /* Debug magic to take advantage of freebsd's mess */ 108 #ifdef LINUX_DEBUG 109 #define LINUX_CTR_PREFIX 110 #else 111 #define LINUX_CTR_PREFIX while (0) 112 #endif 113 114 #define LINUX_CTR1(a,b,c) LINUX_CTR_PREFIX kprintf("linux_futex: " b "\n",c) 115 #define LINUX_CTR2(a,b,c,d) LINUX_CTR_PREFIX kprintf("linux_futex: " b "\n",c,d) 116 #define LINUX_CTR3(a,b,c,d,e) LINUX_CTR_PREFIX kprintf("linux_futex: " b "\n",c,d,e) 117 #define LINUX_CTR4(a,b,c,d,e,f) LINUX_CTR_PREFIX kprintf("linux_futex: " b "\n",c,d,e,f) 118 #define LINUX_CTR5(a,b,c,d,e,f,g) LINUX_CTR_PREFIX kprintf("linux_futex: " b "\n",c,d,e,f,g) 119 120 121 122 /* flags for futex_get() */ 123 #define FUTEX_CREATE_WP 0x1 /* create waiting_proc */ 124 #define FUTEX_DONTCREATE 0x2 /* don't create futex if not exists */ 125 #define FUTEX_DONTEXISTS 0x4 /* return EINVAL if futex exists */ 126 127 /* wp_flags */ 128 #define FUTEX_WP_REQUEUED 0x1 /* wp requeued - wp moved from wp_list 129 * of futex where thread sleep to wp_list 130 * of another futex. 131 */ 132 #define FUTEX_WP_REMOVED 0x2 /* wp is woken up and removed from futex 133 * wp_list to prevent double wakeup. 134 */ 135 136 /* support.s */ 137 int futex_xchgl(int oparg, uint32_t *uaddr, int *oldval); 138 int futex_addl(int oparg, uint32_t *uaddr, int *oldval); 139 int futex_orl(int oparg, uint32_t *uaddr, int *oldval); 140 int futex_andl(int oparg, uint32_t *uaddr, int *oldval); 141 int futex_xorl(int oparg, uint32_t *uaddr, int *oldval); 142 143 static void 144 futex_put(struct futex *f, struct waiting_proc *wp) 145 { 146 FUTEX_ASSERT_LOCKED(f); 147 if (wp != NULL) { 148 if ((wp->wp_flags & FUTEX_WP_REMOVED) == 0) 149 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 150 kfree(wp, M_FUTEX_WP); 151 } 152 153 FUTEXES_LOCK; 154 if (--f->f_refcount == 0) { 155 LIST_REMOVE(f, f_list); 156 FUTEXES_UNLOCK; 157 FUTEX_UNLOCK(f); 158 159 LINUX_CTR2(sys_futex, "futex_put destroy uaddr %p ref %d", 160 f->f_uaddr, f->f_refcount); 161 FUTEX_DESTROY(f); 162 kfree(f, M_FUTEX); 163 return; 164 } 165 166 LINUX_CTR2(sys_futex, "futex_put uaddr %p ref %d", 167 f->f_uaddr, f->f_refcount); 168 FUTEXES_UNLOCK; 169 FUTEX_UNLOCK(f); 170 } 171 172 static int 173 futex_get0(uint32_t *uaddr, struct futex **newf, uint32_t flags) 174 { 175 struct futex *f, *tmpf; 176 177 *newf = tmpf = NULL; 178 179 retry: 180 FUTEXES_LOCK; 181 LIST_FOREACH(f, &futex_list, f_list) { 182 if (f->f_uaddr == uaddr) { 183 if (tmpf != NULL) { 184 FUTEX_UNLOCK(tmpf); 185 FUTEX_DESTROY(tmpf); 186 kfree(tmpf, M_FUTEX); 187 } 188 if (flags & FUTEX_DONTEXISTS) { 189 FUTEXES_UNLOCK; 190 return (EINVAL); 191 } 192 193 /* 194 * Increment refcount of the found futex to 195 * prevent it from deallocation before FUTEX_LOCK() 196 */ 197 ++f->f_refcount; 198 FUTEXES_UNLOCK; 199 200 FUTEX_LOCK(f); 201 *newf = f; 202 LINUX_CTR2(sys_futex, "futex_get uaddr %p ref %d", 203 uaddr, f->f_refcount); 204 return (0); 205 } 206 } 207 208 if (flags & FUTEX_DONTCREATE) { 209 FUTEXES_UNLOCK; 210 LINUX_CTR1(sys_futex, "futex_get uaddr %p null", uaddr); 211 return (0); 212 } 213 214 if (tmpf == NULL) { 215 FUTEXES_UNLOCK; 216 tmpf = kmalloc(sizeof(*tmpf), M_FUTEX, M_WAITOK | M_ZERO); 217 tmpf->f_uaddr = uaddr; 218 tmpf->f_refcount = 1; 219 FUTEX_INIT(tmpf); 220 TAILQ_INIT(&tmpf->f_waiting_proc); 221 222 /* 223 * Lock the new futex before an insert into the futex_list 224 * to prevent futex usage by other. 225 */ 226 FUTEX_LOCK(tmpf); 227 goto retry; 228 } 229 230 LIST_INSERT_HEAD(&futex_list, tmpf, f_list); 231 FUTEXES_UNLOCK; 232 233 LINUX_CTR2(sys_futex, "futex_get uaddr %p ref %d new", 234 uaddr, tmpf->f_refcount); 235 *newf = tmpf; 236 return (0); 237 } 238 239 static int 240 futex_get(uint32_t *uaddr, struct waiting_proc **wp, struct futex **f, 241 uint32_t flags) 242 { 243 int error; 244 245 if (flags & FUTEX_CREATE_WP) { 246 *wp = kmalloc(sizeof(struct waiting_proc), M_FUTEX_WP, M_WAITOK); 247 (*wp)->wp_flags = 0; 248 } 249 error = futex_get0(uaddr, f, flags); 250 if (error) { 251 if (flags & FUTEX_CREATE_WP) 252 kfree(*wp, M_FUTEX_WP); 253 return (error); 254 } 255 if (flags & FUTEX_CREATE_WP) { 256 TAILQ_INSERT_HEAD(&(*f)->f_waiting_proc, *wp, wp_list); 257 (*wp)->wp_futex = *f; 258 } 259 260 return (error); 261 } 262 263 static int 264 futex_sleep(struct futex *f, struct waiting_proc *wp, int timeout) 265 { 266 int error; 267 268 FUTEX_ASSERT_LOCKED(f); 269 LINUX_CTR4(sys_futex, "futex_sleep enter uaddr %p wp %p timo %d ref %d", 270 f->f_uaddr, wp, timeout, f->f_refcount); 271 error = FUTEX_SLEEP(f, wp, PCATCH, "futex", timeout); 272 if (wp->wp_flags & FUTEX_WP_REQUEUED) { 273 KASSERT(f != wp->wp_futex, ("futex != wp_futex")); 274 LINUX_CTR5(sys_futex, "futex_sleep out error %d uaddr %p w" 275 " %p requeued uaddr %p ref %d", 276 error, f->f_uaddr, wp, wp->wp_futex->f_uaddr, 277 wp->wp_futex->f_refcount); 278 futex_put(f, NULL); 279 f = wp->wp_futex; 280 FUTEX_LOCK(f); 281 } 282 283 futex_put(f, wp); 284 return (error); 285 } 286 287 static int 288 futex_wake(struct futex *f, int n) 289 { 290 struct waiting_proc *wp, *wpt; 291 int count = 0; 292 293 FUTEX_ASSERT_LOCKED(f); 294 TAILQ_FOREACH_MUTABLE(wp, &f->f_waiting_proc, wp_list, wpt) { 295 LINUX_CTR3(sys_futex, "futex_wake uaddr %p wp %p ref %d", 296 f->f_uaddr, wp, f->f_refcount); 297 wp->wp_flags |= FUTEX_WP_REMOVED; 298 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 299 wakeup_one(wp); 300 if (++count == n) 301 break; 302 } 303 304 return (count); 305 } 306 307 static int 308 futex_requeue(struct futex *f, int n, struct futex *f2, int n2) 309 { 310 struct waiting_proc *wp, *wpt; 311 int count = 0; 312 313 FUTEX_ASSERT_LOCKED(f); 314 FUTEX_ASSERT_LOCKED(f2); 315 316 TAILQ_FOREACH_MUTABLE(wp, &f->f_waiting_proc, wp_list, wpt) { 317 if (++count <= n) { 318 LINUX_CTR2(sys_futex, "futex_req_wake uaddr %p wp %p", 319 f->f_uaddr, wp); 320 wp->wp_flags |= FUTEX_WP_REMOVED; 321 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 322 wakeup_one(wp); 323 } else { 324 LINUX_CTR3(sys_futex, "futex_requeue uaddr %p wp %p to %p", 325 f->f_uaddr, wp, f2->f_uaddr); 326 wp->wp_flags |= FUTEX_WP_REQUEUED; 327 /* Move wp to wp_list of f2 futex */ 328 TAILQ_REMOVE(&f->f_waiting_proc, wp, wp_list); 329 TAILQ_INSERT_HEAD(&f2->f_waiting_proc, wp, wp_list); 330 331 /* 332 * Thread which sleeps on wp after waking should 333 * acquire f2 lock, so increment refcount of f2 to 334 * prevent it from premature deallocation. 335 */ 336 wp->wp_futex = f2; 337 FUTEXES_LOCK; 338 ++f2->f_refcount; 339 FUTEXES_UNLOCK; 340 if (count - n >= n2) 341 break; 342 } 343 } 344 345 return (count); 346 } 347 348 static int 349 futex_wait(struct futex *f, struct waiting_proc *wp, struct l_timespec *ts) 350 { 351 struct l_timespec timeout; 352 struct timeval tv; 353 int timeout_hz; 354 int error; 355 356 if (ts != NULL) { 357 error = copyin(ts, &timeout, sizeof(timeout)); 358 if (error) 359 return (error); 360 TIMESPEC_TO_TIMEVAL(&tv, &timeout); 361 error = itimerfix(&tv); 362 if (error) 363 return (error); 364 timeout_hz = tvtohz_high(&tv); 365 } else { 366 timeout_hz = 0; 367 } 368 369 error = futex_sleep(f, wp, timeout_hz); 370 if (error == EWOULDBLOCK) 371 error = ETIMEDOUT; 372 373 return (error); 374 } 375 376 static int 377 futex_atomic_op(struct proc *p, int encoded_op, uint32_t *uaddr) 378 { 379 int op = (encoded_op >> 28) & 7; 380 int cmp = (encoded_op >> 24) & 15; 381 int oparg = (encoded_op << 8) >> 20; 382 int cmparg = (encoded_op << 20) >> 20; 383 int oldval = 0, ret; 384 385 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) 386 oparg = 1 << oparg; 387 388 #ifdef DEBUG 389 if (ldebug(sys_futex)) 390 kprintf("futex_atomic_op: op = %d, cmp = %d, oparg = %x, " 391 "cmparg = %x, uaddr = %p\n", 392 op, cmp, oparg, cmparg, uaddr); 393 #endif 394 /* XXX: linux verifies access here and returns EFAULT */ 395 396 switch (op) { 397 case FUTEX_OP_SET: 398 ret = futex_xchgl(oparg, uaddr, &oldval); 399 break; 400 case FUTEX_OP_ADD: 401 ret = futex_addl(oparg, uaddr, &oldval); 402 break; 403 case FUTEX_OP_OR: 404 ret = futex_orl(oparg, uaddr, &oldval); 405 break; 406 case FUTEX_OP_ANDN: 407 ret = futex_andl(~oparg, uaddr, &oldval); 408 break; 409 case FUTEX_OP_XOR: 410 ret = futex_xorl(oparg, uaddr, &oldval); 411 break; 412 default: 413 ret = -ENOSYS; 414 break; 415 } 416 417 if (ret) 418 return (ret); 419 420 switch (cmp) { 421 case FUTEX_OP_CMP_EQ: 422 return (oldval == cmparg); 423 case FUTEX_OP_CMP_NE: 424 return (oldval != cmparg); 425 case FUTEX_OP_CMP_LT: 426 return (oldval < cmparg); 427 case FUTEX_OP_CMP_GE: 428 return (oldval >= cmparg); 429 case FUTEX_OP_CMP_LE: 430 return (oldval <= cmparg); 431 case FUTEX_OP_CMP_GT: 432 return (oldval > cmparg); 433 default: 434 return (-ENOSYS); 435 } 436 } 437 438 int 439 sys_linux_sys_futex(struct linux_sys_futex_args *args) 440 { 441 int op_ret, val, ret, nrwake; 442 struct waiting_proc *wp; 443 struct futex *f, *f2 = NULL; 444 int error = 0; 445 446 /* 447 * Our implementation provides only privates futexes. Most of the apps 448 * should use private futexes but don't claim so. Therefore we treat 449 * all futexes as private by clearing the FUTEX_PRIVATE_FLAG. It works 450 * in most cases (ie. when futexes are not shared on file descriptor 451 * or between different processes.). 452 */ 453 args->op = (args->op & ~LINUX_FUTEX_PRIVATE_FLAG); 454 455 switch (args->op) { 456 case LINUX_FUTEX_WAIT: 457 LINUX_CTR2(sys_futex, "WAIT val %d uaddr %p", 458 args->val, args->uaddr); 459 #ifdef DEBUG 460 if (ldebug(sys_futex)) 461 kprintf(ARGS(sys_futex, "futex_wait val %d uaddr %p"), 462 args->val, args->uaddr); 463 #endif 464 error = futex_get(args->uaddr, &wp, &f, FUTEX_CREATE_WP); 465 if (error) 466 return (error); 467 error = copyin(args->uaddr, &val, sizeof(val)); 468 if (error) { 469 LINUX_CTR1(sys_futex, "WAIT copyin failed %d", 470 error); 471 futex_put(f, wp); 472 return (error); 473 } 474 if (val != args->val) { 475 LINUX_CTR3(sys_futex, "WAIT uaddr %p val %d != uval %d", 476 args->uaddr, args->val, val); 477 futex_put(f, wp); 478 return (EWOULDBLOCK); 479 } 480 481 error = futex_wait(f, wp, args->timeout); 482 break; 483 484 case LINUX_FUTEX_WAKE: 485 486 LINUX_CTR2(sys_futex, "WAKE val %d uaddr %p", 487 args->val, args->uaddr); 488 489 /* 490 * XXX: Linux is able to cope with different addresses 491 * corresponding to the same mapped memory in the sleeping 492 * and waker process(es). 493 */ 494 #ifdef DEBUG 495 if (ldebug(sys_futex)) 496 kprintf(ARGS(sys_futex, "futex_wake val %d uaddr %p"), 497 args->val, args->uaddr); 498 #endif 499 error = futex_get(args->uaddr, NULL, &f, FUTEX_DONTCREATE); 500 if (error) 501 return (error); 502 if (f == NULL) { 503 args->sysmsg_iresult = 0; 504 return (error); 505 } 506 args->sysmsg_iresult = futex_wake(f, args->val); 507 futex_put(f, NULL); 508 break; 509 510 case LINUX_FUTEX_CMP_REQUEUE: 511 512 LINUX_CTR5(sys_futex, "CMP_REQUEUE uaddr %p " 513 "val %d val3 %d uaddr2 %p val2 %d", 514 args->uaddr, args->val, args->val3, args->uaddr2, 515 (int)(unsigned long)args->timeout); 516 517 #ifdef DEBUG 518 if (ldebug(sys_futex)) 519 kprintf(ARGS(sys_futex, "futex_cmp_requeue uaddr %p " 520 "val %d val3 %d uaddr2 %p val2 %d"), 521 args->uaddr, args->val, args->val3, args->uaddr2, 522 (int)(unsigned long)args->timeout); 523 #endif 524 /* 525 * Linux allows this, we would not, it is an incorrect 526 * usage of declared ABI, so return EINVAL. 527 */ 528 if (args->uaddr == args->uaddr2) 529 return (EINVAL); 530 error = futex_get0(args->uaddr, &f, 0); 531 if (error) 532 return (error); 533 534 /* 535 * To avoid deadlocks return EINVAL if second futex 536 * exists at this time. Otherwise create the new futex 537 * and ignore false positive LOR which thus happens. 538 * 539 * Glibc fall back to FUTEX_WAKE in case of any error 540 * returned by FUTEX_CMP_REQUEUE. 541 */ 542 error = futex_get0(args->uaddr2, &f2, FUTEX_DONTEXISTS); 543 if (error) { 544 futex_put(f, NULL); 545 return (error); 546 } 547 error = copyin(args->uaddr, &val, sizeof(val)); 548 if (error) { 549 LINUX_CTR1(sys_futex, "CMP_REQUEUE copyin failed %d", 550 error); 551 futex_put(f2, NULL); 552 futex_put(f, NULL); 553 return (error); 554 } 555 if (val != args->val3) { 556 LINUX_CTR2(sys_futex, "CMP_REQUEUE val %d != uval %d", 557 args->val, val); 558 futex_put(f2, NULL); 559 futex_put(f, NULL); 560 return (EAGAIN); 561 } 562 563 nrwake = (int)(unsigned long)args->timeout; 564 args->sysmsg_iresult = futex_requeue(f, args->val, f2, nrwake); 565 futex_put(f2, NULL); 566 futex_put(f, NULL); 567 break; 568 569 case LINUX_FUTEX_WAKE_OP: 570 571 LINUX_CTR5(sys_futex, "WAKE_OP " 572 "uaddr %p op %d val %x uaddr2 %p val3 %x", 573 args->uaddr, args->op, args->val, 574 args->uaddr2, args->val3); 575 576 #ifdef DEBUG 577 if (ldebug(sys_futex)) 578 kprintf(ARGS(sys_futex, "futex_wake_op " 579 "uaddr %p op %d val %x uaddr2 %p val3 %x"), 580 args->uaddr, args->op, args->val, 581 args->uaddr2, args->val3); 582 #endif 583 error = futex_get0(args->uaddr, &f, 0); 584 if (error) 585 return (error); 586 if (args->uaddr != args->uaddr2) 587 error = futex_get0(args->uaddr2, &f2, 0); 588 if (error) { 589 futex_put(f, NULL); 590 return (error); 591 } 592 593 /* 594 * This function returns positive number as results and 595 * negative as errors 596 */ 597 op_ret = futex_atomic_op(curproc, args->val3, args->uaddr2); 598 599 if (op_ret < 0) { 600 /* XXX: We don't handle the EFAULT yet. */ 601 if (op_ret != -EFAULT) { 602 if (f2 != NULL) 603 futex_put(f2, NULL); 604 futex_put(f, NULL); 605 return (-op_ret); 606 } 607 if (f2 != NULL) 608 futex_put(f2, NULL); 609 futex_put(f, NULL); 610 return (EFAULT); 611 } 612 613 ret = futex_wake(f, args->val); 614 615 if (op_ret > 0) { 616 op_ret = 0; 617 nrwake = (int)(unsigned long)args->timeout; 618 619 if (f2 != NULL) 620 op_ret += futex_wake(f2, nrwake); 621 else 622 op_ret += futex_wake(f, nrwake); 623 ret += op_ret; 624 625 } 626 if (f2 != NULL) 627 futex_put(f2, NULL); 628 futex_put(f, NULL); 629 args->sysmsg_iresult = ret; 630 break; 631 632 case LINUX_FUTEX_LOCK_PI: 633 /* not yet implemented */ 634 return (ENOSYS); 635 636 case LINUX_FUTEX_UNLOCK_PI: 637 /* not yet implemented */ 638 return (ENOSYS); 639 640 case LINUX_FUTEX_TRYLOCK_PI: 641 /* not yet implemented */ 642 return (ENOSYS); 643 644 case LINUX_FUTEX_REQUEUE: 645 646 /* 647 * Glibc does not use this operation since version 2.3.3, 648 * as it is racy and replaced by FUTEX_CMP_REQUEUE operation. 649 * Glibc versions prior to 2.3.3 fall back to FUTEX_WAKE when 650 * FUTEX_REQUEUE returned EINVAL. 651 */ 652 return (EINVAL); 653 654 default: 655 kprintf("linux_sys_futex: unknown op %d\n", args->op); 656 return (ENOSYS); 657 } 658 659 return (error); 660 } 661 662 int 663 sys_linux_set_robust_list(struct linux_set_robust_list_args *args) 664 { 665 #ifdef DEBUG 666 if (ldebug(set_robust_list)) 667 kprintf(ARGS(set_robust_list, "head %p len %d"), 668 args->head, args->len); 669 #endif 670 671 if (args->len != sizeof(struct linux_robust_list_head)) 672 return (EINVAL); 673 674 emuldata_set_robust(curproc, args->head); 675 676 return (0); 677 } 678 679 680 681 int 682 sys_linux_get_robust_list(struct linux_get_robust_list_args *args) 683 { 684 struct linux_emuldata *em; 685 struct linux_robust_list_head empty_head; 686 struct linux_robust_list_head *head; 687 l_size_t len = sizeof(struct linux_robust_list_head); 688 int error = 0; 689 690 #ifdef DEBUG 691 if (ldebug(get_robust_list)) 692 kprintf(ARGS(get_robust_list, "")); 693 #endif 694 695 if (args->pid == 0) { 696 EMUL_LOCK(); 697 em = emuldata_get(curproc); 698 KKASSERT(em != NULL); 699 if (em->robust_futexes == NULL) { 700 bzero(&empty_head, sizeof(empty_head)); 701 head = &empty_head; 702 } else { 703 head = em->robust_futexes; 704 } 705 EMUL_UNLOCK(); 706 } else { 707 struct proc *p; 708 709 p = pfind(args->pid); 710 if (p == NULL) { 711 return (ESRCH); 712 } 713 714 EMUL_LOCK(); 715 em = emuldata_get(p); 716 head = em->robust_futexes; 717 EMUL_UNLOCK(); 718 /* XXX: ptrace? p_candebug?*/ 719 if (priv_check(curthread, PRIV_CRED_SETUID) || 720 priv_check(curthread, PRIV_CRED_SETEUID)/* || 721 p_candebug(curproc, p) */) { 722 PRELE(p); 723 return (EPERM); 724 } 725 PRELE(p); 726 } 727 728 error = copyout(&len, args->len, sizeof(l_size_t)); 729 if (error) 730 return (EFAULT); 731 732 error = copyout(head, args->head, sizeof(struct linux_robust_list_head)); 733 734 return (error); 735 } 736 737 static int 738 handle_futex_death(struct proc *p, uint32_t *uaddr, int pi) 739 { 740 uint32_t uval, nval, mval; 741 struct futex *f; 742 int error; 743 744 retry: 745 if (copyin(uaddr, &uval, 4)) 746 return (EFAULT); 747 if ((uval & FUTEX_TID_MASK) == p->p_pid) { 748 mval = (uval & FUTEX_WAITERS) | FUTEX_OWNER_DIED; 749 nval = casuword((ulong *)uaddr, uval, mval); 750 751 if (nval == -1) 752 return (EFAULT); 753 754 if (nval != uval) 755 goto retry; 756 757 if (!pi && (uval & FUTEX_WAITERS)) { 758 error = futex_get(uaddr, NULL, &f, 759 FUTEX_DONTCREATE); 760 if (error) 761 return (error); 762 if (f != NULL) { 763 futex_wake(f, 1); 764 futex_put(f, NULL); 765 } 766 } 767 } 768 769 return (0); 770 } 771 772 static int 773 fetch_robust_entry(struct linux_robust_list **entry, 774 struct linux_robust_list **head, int *pi) 775 { 776 l_ulong uentry; 777 778 if (copyin((const void *)head, &uentry, sizeof(l_ulong))) 779 return (EFAULT); 780 781 *entry = (void *)(uentry & ~1UL); 782 *pi = uentry & 1; 783 784 return (0); 785 } 786 787 /* This walks the list of robust futexes releasing them. */ 788 void 789 release_futexes(struct proc *p) 790 { 791 struct linux_robust_list_head *head = NULL; 792 struct linux_robust_list *entry, *next_entry, *pending; 793 unsigned int limit = 2048, pi, next_pi, pip; 794 struct linux_emuldata *em; 795 l_long futex_offset; 796 int rc; 797 798 EMUL_LOCK(); 799 KKASSERT(p != NULL); 800 em = emuldata_get(p); 801 KKASSERT(em != NULL); 802 head = em->robust_futexes; 803 EMUL_UNLOCK(); 804 805 if (head == NULL) 806 return; 807 808 if (fetch_robust_entry(&entry, PTRIN(&head->list.next), &pi)) 809 return; 810 811 if (copyin(&head->futex_offset, &futex_offset, sizeof(futex_offset))) 812 return; 813 814 if (fetch_robust_entry(&pending, PTRIN(&head->pending_list), &pip)) 815 return; 816 817 while (entry != &head->list) { 818 rc = fetch_robust_entry(&next_entry, PTRIN(&entry->next), &next_pi); 819 820 if (entry != pending) 821 if (handle_futex_death(p, (uint32_t *)entry + futex_offset, pi)) 822 return; 823 if (rc) 824 return; 825 826 entry = next_entry; 827 pi = next_pi; 828 829 if (!--limit) 830 break; 831 832 /* XXX: not sure about this yield, was sched_relinquish(curthread); */ 833 lwkt_yield(); 834 } 835 836 if (pending) 837 handle_futex_death(p, (uint32_t *)pending + futex_offset, pip); 838 }
Cache object: e63c460a66c7c6d0fcc3ac40350b1f6f
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