Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 | /* Copyright (C) 2002-2007, 2009 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ #include <assert.h> #include <errno.h> #include <signal.h> #include <stdint.h> #include <string.h> #include <unistd.h> #include <sys/mman.h> #include <sys/param.h> #include <tls.h> #include <lowlevellock.h> #include <link.h> #include <bits/kernel-features.h> #ifndef NEED_SEPARATE_REGISTER_STACK /* Most architectures have exactly one stack pointer. Some have more. */ # define STACK_VARIABLES void *stackaddr = NULL /* How to pass the values to the 'create_thread' function. */ # define STACK_VARIABLES_ARGS stackaddr /* How to declare function which gets there parameters. */ # define STACK_VARIABLES_PARMS void *stackaddr /* How to declare allocate_stack. */ # define ALLOCATE_STACK_PARMS void **stack /* This is how the function is called. We do it this way to allow other variants of the function to have more parameters. */ # define ALLOCATE_STACK(attr, pd) allocate_stack (attr, pd, &stackaddr) #else /* We need two stacks. The kernel will place them but we have to tell the kernel about the size of the reserved address space. */ # define STACK_VARIABLES void *stackaddr = NULL; size_t stacksize = 0 /* How to pass the values to the 'create_thread' function. */ # define STACK_VARIABLES_ARGS stackaddr, stacksize /* How to declare function which gets there parameters. */ # define STACK_VARIABLES_PARMS void *stackaddr, size_t stacksize /* How to declare allocate_stack. */ # define ALLOCATE_STACK_PARMS void **stack, size_t *stacksize /* This is how the function is called. We do it this way to allow other variants of the function to have more parameters. */ # define ALLOCATE_STACK(attr, pd) \ allocate_stack (attr, pd, &stackaddr, &stacksize) #endif /* Default alignment of stack. */ #ifndef STACK_ALIGN # define STACK_ALIGN __alignof__ (long double) #endif /* Default value for minimal stack size after allocating thread descriptor and guard. */ #ifndef MINIMAL_REST_STACK # define MINIMAL_REST_STACK 4096 #endif /* Newer kernels have the MAP_STACK flag to indicate a mapping is used for a stack. Use it when possible. */ #ifndef MAP_STACK # define MAP_STACK 0 #endif /* This yields the pointer that TLS support code calls the thread pointer. */ #if defined(TLS_TCB_AT_TP) # define TLS_TPADJ(pd) (pd) #elif defined(TLS_DTV_AT_TP) # define TLS_TPADJ(pd) ((struct pthread *)((char *) (pd) + TLS_PRE_TCB_SIZE)) #endif /* Cache handling for not-yet free stacks. */ /* Maximum size in kB of cache. */ static size_t stack_cache_maxsize = 40 * 1024 * 1024; /* 40MiBi by default. */ static size_t stack_cache_actsize; /* Mutex protecting this variable. */ static int stack_cache_lock = LLL_LOCK_INITIALIZER; /* List of queued stack frames. */ static LIST_HEAD (stack_cache); /* List of the stacks in use. */ static LIST_HEAD (stack_used); /* We need to record what list operations we are going to do so that, in case of an asynchronous interruption due to a fork() call, we can correct for the work. */ static uintptr_t in_flight_stack; /* List of the threads with user provided stacks in use. No need to initialize this, since it's done in __pthread_initialize_minimal. */ list_t __stack_user __attribute__ ((nocommon)); hidden_data_def (__stack_user) #if defined COLORING_INCREMENT && COLORING_INCREMENT != 0 /* Number of threads created. */ static unsigned int nptl_ncreated; #endif /* Check whether the stack is still used or not. */ #define FREE_P(descr) ((descr)->tid <= 0) static void stack_list_del (list_t *elem) { in_flight_stack = (uintptr_t) elem; atomic_write_barrier (); list_del (elem); atomic_write_barrier (); in_flight_stack = 0; } static void stack_list_add (list_t *elem, list_t *list) { in_flight_stack = (uintptr_t) elem | 1; atomic_write_barrier (); list_add (elem, list); atomic_write_barrier (); in_flight_stack = 0; } /* We create a double linked list of all cache entries. Double linked because this allows removing entries from the end. */ /* Get a stack frame from the cache. We have to match by size since some blocks might be too small or far too large. */ static struct pthread * get_cached_stack (size_t *sizep, void **memp) { size_t size = *sizep; struct pthread *result = NULL; list_t *entry; lll_lock (stack_cache_lock, LLL_PRIVATE); /* Search the cache for a matching entry. We search for the smallest stack which has at least the required size. Note that in normal situations the size of all allocated stacks is the same. As the very least there are only a few different sizes. Therefore this loop will exit early most of the time with an exact match. */ list_for_each (entry, &stack_cache) { struct pthread *curr; curr = list_entry (entry, struct pthread, list); if (FREE_P (curr) && curr->stackblock_size >= size) { if (curr->stackblock_size == size) { result = curr; break; } if (result == NULL || result->stackblock_size > curr->stackblock_size) result = curr; } } if (__builtin_expect (result == NULL, 0) /* Make sure the size difference is not too excessive. In that case we do not use the block. */ || __builtin_expect (result->stackblock_size > 4 * size, 0)) { /* Release the lock. */ lll_unlock (stack_cache_lock, LLL_PRIVATE); return NULL; } /* Dequeue the entry. */ stack_list_del (&result->list); /* And add to the list of stacks in use. */ stack_list_add (&result->list, &stack_used); /* And decrease the cache size. */ stack_cache_actsize -= result->stackblock_size; /* Release the lock early. */ lll_unlock (stack_cache_lock, LLL_PRIVATE); /* Report size and location of the stack to the caller. */ *sizep = result->stackblock_size; *memp = result->stackblock; /* Cancellation handling is back to the default. */ result->cancelhandling = 0; result->cleanup = NULL; /* No pending event. */ result->nextevent = NULL; /* Clear the DTV. */ dtv_t *dtv = GET_DTV (TLS_TPADJ (result)); memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t)); /* Re-initialize the TLS. */ _dl_allocate_tls_init (TLS_TPADJ (result)); return result; } /* Free stacks until cache size is lower than LIMIT. */ void __free_stacks (size_t limit) { /* We reduce the size of the cache. Remove the last entries until the size is below the limit. */ list_t *entry; list_t *prev; /* Search from the end of the list. */ list_for_each_prev_safe (entry, prev, &stack_cache) { struct pthread *curr; curr = list_entry (entry, struct pthread, list); if (FREE_P (curr)) { /* Unlink the block. */ stack_list_del (entry); /* Account for the freed memory. */ stack_cache_actsize -= curr->stackblock_size; /* Free the memory associated with the ELF TLS. */ _dl_deallocate_tls (TLS_TPADJ (curr), false); /* Remove this block. This should never fail. If it does something is really wrong. */ if (munmap (curr->stackblock, curr->stackblock_size) != 0) abort (); /* Maybe we have freed enough. */ if (stack_cache_actsize <= limit) break; } } } /* Add a stack frame which is not used anymore to the stack. Must be called with the cache lock held. */ static inline void __attribute ((always_inline)) queue_stack (struct pthread *stack) { /* We unconditionally add the stack to the list. The memory may still be in use but it will not be reused until the kernel marks the stack as not used anymore. */ stack_list_add (&stack->list, &stack_cache); stack_cache_actsize += stack->stackblock_size; if (__builtin_expect (stack_cache_actsize > stack_cache_maxsize, 0)) __free_stacks (stack_cache_maxsize); } static int internal_function change_stack_perm (struct pthread *pd #ifdef NEED_SEPARATE_REGISTER_STACK , size_t pagemask #endif ) { #ifdef NEED_SEPARATE_REGISTER_STACK void *stack = (pd->stackblock + (((((pd->stackblock_size - pd->guardsize) / 2) & pagemask) + pd->guardsize) & pagemask)); size_t len = pd->stackblock + pd->stackblock_size - stack; #elif defined _STACK_GROWS_DOWN void *stack = pd->stackblock + pd->guardsize; size_t len = pd->stackblock_size - pd->guardsize; #elif defined _STACK_GROWS_UP void *stack = pd->stackblock; size_t len = (uintptr_t) pd - pd->guardsize - (uintptr_t) pd->stackblock; #else # error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP" #endif if (mprotect (stack, len, PROT_READ | PROT_WRITE | PROT_EXEC) != 0) return errno; return 0; } static int allocate_stack (const struct pthread_attr *attr, struct pthread **pdp, ALLOCATE_STACK_PARMS) { struct pthread *pd; size_t size; size_t pagesize_m1 = __getpagesize () - 1; void *stacktop; assert (attr != NULL); assert (powerof2 (pagesize_m1 + 1)); assert (TCB_ALIGNMENT >= STACK_ALIGN); /* Get the stack size from the attribute if it is set. Otherwise we use the default we determined at start time. */ size = attr->stacksize ?: __default_stacksize; /* Get memory for the stack. */ if (__builtin_expect (attr->flags & ATTR_FLAG_STACKADDR, 0)) { uintptr_t adj; /* If the user also specified the size of the stack make sure it is large enough. */ if (attr->stacksize != 0 && attr->stacksize < (__static_tls_size + MINIMAL_REST_STACK)) return EINVAL; /* Adjust stack size for alignment of the TLS block. */ #if defined(TLS_TCB_AT_TP) adj = ((uintptr_t) attr->stackaddr - TLS_TCB_SIZE) & __static_tls_align_m1; assert (size > adj + TLS_TCB_SIZE); #elif defined(TLS_DTV_AT_TP) adj = ((uintptr_t) attr->stackaddr - __static_tls_size) & __static_tls_align_m1; assert (size > adj); #endif /* The user provided some memory. Let's hope it matches the size... We do not allocate guard pages if the user provided the stack. It is the user's responsibility to do this if it is wanted. */ #if defined(TLS_TCB_AT_TP) pd = (struct pthread *) ((uintptr_t) attr->stackaddr - TLS_TCB_SIZE - adj); #elif defined(TLS_DTV_AT_TP) pd = (struct pthread *) (((uintptr_t) attr->stackaddr - __static_tls_size - adj) - TLS_PRE_TCB_SIZE); #endif /* The user provided stack memory needs to be cleared. */ memset (pd, '\0', sizeof (struct pthread)); /* The first TSD block is included in the TCB. */ pd->specific[0] = pd->specific_1stblock; /* Remember the stack-related values. */ pd->stackblock = (char *) attr->stackaddr - size; pd->stackblock_size = size; /* This is a user-provided stack. It will not be queued in the stack cache nor will the memory (except the TLS memory) be freed. */ pd->user_stack = true; /* This is at least the second thread. */ pd->header.multiple_threads = 1; #ifndef TLS_MULTIPLE_THREADS_IN_TCB __pthread_multiple_threads = *__libc_multiple_threads_ptr = 1; #endif #ifndef __ASSUME_PRIVATE_FUTEX /* The thread must know when private futexes are supported. */ pd->header.private_futex = THREAD_GETMEM (THREAD_SELF, header.private_futex); #endif #ifdef NEED_DL_SYSINFO /* Copy the sysinfo value from the parent. */ THREAD_SYSINFO(pd) = THREAD_SELF_SYSINFO; #endif /* The process ID is also the same as that of the caller. */ pd->pid = THREAD_GETMEM (THREAD_SELF, pid); /* Allocate the DTV for this thread. */ if (_dl_allocate_tls (TLS_TPADJ (pd)) == NULL) { /* Something went wrong. */ assert (errno == ENOMEM); return EAGAIN; } /* Prepare to modify global data. */ lll_lock (stack_cache_lock, LLL_PRIVATE); /* And add to the list of stacks in use. */ list_add (&pd->list, &__stack_user); lll_unlock (stack_cache_lock, LLL_PRIVATE); } else { /* Allocate some anonymous memory. If possible use the cache. */ size_t guardsize; size_t reqsize; void *mem = 0; const int prot = (PROT_READ | PROT_WRITE); #if defined COLORING_INCREMENT && COLORING_INCREMENT != 0 /* Add one more page for stack coloring. Don't do it for stacks with 16 times pagesize or larger. This might just cause unnecessary misalignment. */ if (size <= 16 * pagesize_m1) size += pagesize_m1 + 1; #endif /* Adjust the stack size for alignment. */ size &= ~__static_tls_align_m1; assert (size != 0); /* Make sure the size of the stack is enough for the guard and eventually the thread descriptor. */ guardsize = (attr->guardsize + pagesize_m1) & ~pagesize_m1; if (__builtin_expect (size < ((guardsize + __static_tls_size + MINIMAL_REST_STACK + pagesize_m1) & ~pagesize_m1), 0)) /* The stack is too small (or the guard too large). */ return EINVAL; /* Try to get a stack from the cache. */ reqsize = size; pd = get_cached_stack (&size, &mem); if (pd == NULL) { /* To avoid aliasing effects on a larger scale than pages we adjust the allocated stack size if necessary. This way allocations directly following each other will not have aliasing problems. */ #if defined MULTI_PAGE_ALIASING && MULTI_PAGE_ALIASING != 0 if ((size % MULTI_PAGE_ALIASING) == 0) size += pagesize_m1 + 1; #endif mem = mmap (NULL, size, prot, MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0); if (__builtin_expect (mem == MAP_FAILED, 0)) { if (errno == ENOMEM) __set_errno (EAGAIN); return errno; } /* SIZE is guaranteed to be greater than zero. So we can never get a null pointer back from mmap. */ assert (mem != NULL); #if defined COLORING_INCREMENT && COLORING_INCREMENT != 0 /* Atomically increment NCREATED. */ unsigned int ncreated = atomic_increment_val (&nptl_ncreated); /* We chose the offset for coloring by incrementing it for every new thread by a fixed amount. The offset used module the page size. Even if coloring would be better relative to higher alignment values it makes no sense to do it since the mmap() interface does not allow us to specify any alignment for the returned memory block. */ size_t coloring = (ncreated * COLORING_INCREMENT) & pagesize_m1; /* Make sure the coloring offsets does not disturb the alignment of the TCB and static TLS block. */ if (__builtin_expect ((coloring & __static_tls_align_m1) != 0, 0)) coloring = (((coloring + __static_tls_align_m1) & ~(__static_tls_align_m1)) & ~pagesize_m1); #else /* Unless specified we do not make any adjustments. */ # define coloring 0 #endif /* Place the thread descriptor at the end of the stack. */ #if defined(TLS_TCB_AT_TP) pd = (struct pthread *) ((char *) mem + size - coloring) - 1; #elif defined(TLS_DTV_AT_TP) pd = (struct pthread *) ((((uintptr_t) mem + size - coloring - __static_tls_size) & ~__static_tls_align_m1) - TLS_PRE_TCB_SIZE); #endif /* Remember the stack-related values. */ pd->stackblock = mem; pd->stackblock_size = size; /* We allocated the first block thread-specific data array. This address will not change for the lifetime of this descriptor. */ pd->specific[0] = pd->specific_1stblock; /* This is at least the second thread. */ pd->header.multiple_threads = 1; #ifndef TLS_MULTIPLE_THREADS_IN_TCB __pthread_multiple_threads = *__libc_multiple_threads_ptr = 1; #endif #ifndef __ASSUME_PRIVATE_FUTEX /* The thread must know when private futexes are supported. */ pd->header.private_futex = THREAD_GETMEM (THREAD_SELF, header.private_futex); #endif #ifdef NEED_DL_SYSINFO /* Copy the sysinfo value from the parent. */ THREAD_SYSINFO(pd) = THREAD_SELF_SYSINFO; #endif /* The process ID is also the same as that of the caller. */ pd->pid = THREAD_GETMEM (THREAD_SELF, pid); /* Allocate the DTV for this thread. */ if (_dl_allocate_tls (TLS_TPADJ (pd)) == NULL) { /* Something went wrong. */ assert (errno == ENOMEM); /* Free the stack memory we just allocated. */ (void) munmap (mem, size); return EAGAIN; } /* Prepare to modify global data. */ lll_lock (stack_cache_lock, LLL_PRIVATE); /* And add to the list of stacks in use. */ stack_list_add (&pd->list, &stack_used); lll_unlock (stack_cache_lock, LLL_PRIVATE); /* Note that all of the stack and the thread descriptor is zeroed. This means we do not have to initialize fields with initial value zero. This is specifically true for the 'tid' field which is always set back to zero once the stack is not used anymore and for the 'guardsize' field which will be read next. */ } /* Create or resize the guard area if necessary. */ if (__builtin_expect (guardsize > pd->guardsize, 0)) { #ifdef NEED_SEPARATE_REGISTER_STACK char *guard = mem + (((size - guardsize) / 2) & ~pagesize_m1); #elif defined _STACK_GROWS_DOWN char *guard = mem; #elif defined _STACK_GROWS_UP char *guard = (char *) (((uintptr_t) pd - guardsize) & ~pagesize_m1); #endif if (mprotect (guard, guardsize, PROT_NONE) != 0) { int err; mprot_error: err = errno; lll_lock (stack_cache_lock, LLL_PRIVATE); /* Remove the thread from the list. */ stack_list_del (&pd->list); lll_unlock (stack_cache_lock, LLL_PRIVATE); /* Get rid of the TLS block we allocated. */ _dl_deallocate_tls (TLS_TPADJ (pd), false); /* Free the stack memory regardless of whether the size of the cache is over the limit or not. If this piece of memory caused problems we better do not use it anymore. Uh, and we ignore possible errors. There is nothing we could do. */ (void) munmap (mem, size); return err; } pd->guardsize = guardsize; } else if (__builtin_expect (pd->guardsize - guardsize > size - reqsize, 0)) { /* The old guard area is too large. */ #ifdef NEED_SEPARATE_REGISTER_STACK char *guard = mem + (((size - guardsize) / 2) & ~pagesize_m1); char *oldguard = mem + (((size - pd->guardsize) / 2) & ~pagesize_m1); if (oldguard < guard && mprotect (oldguard, guard - oldguard, prot) != 0) goto mprot_error; if (mprotect (guard + guardsize, oldguard + pd->guardsize - guard - guardsize, prot) != 0) goto mprot_error; #elif defined _STACK_GROWS_DOWN if (mprotect ((char *) mem + guardsize, pd->guardsize - guardsize, prot) != 0) goto mprot_error; #elif defined _STACK_GROWS_UP if (mprotect ((char *) (((uintptr_t) pd - pd->guardsize) & ~pagesize_m1), pd->guardsize - guardsize, prot) != 0) goto mprot_error; #endif pd->guardsize = guardsize; } /* The pthread_getattr_np() calls need to get passed the size requested in the attribute, regardless of how large the actually used guardsize is. */ pd->reported_guardsize = guardsize; } /* Initialize the lock. We have to do this unconditionally since the stillborn thread could be canceled while the lock is taken. */ pd->lock = LLL_LOCK_INITIALIZER; /* The robust mutex lists also need to be initialized unconditionally because the cleanup for the previous stack owner might have happened in the kernel. */ pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock) - offsetof (pthread_mutex_t, __data.__list.__next)); pd->robust_head.list_op_pending = NULL; #ifdef __PTHREAD_MUTEX_HAVE_PREV pd->robust_prev = &pd->robust_head; #endif pd->robust_head.list = &pd->robust_head; /* We place the thread descriptor at the end of the stack. */ *pdp = pd; #if defined(TLS_TCB_AT_TP) /* The stack begins before the TCB and the static TLS block. */ stacktop = ((char *) (pd + 1) - __static_tls_size); #elif defined(TLS_DTV_AT_TP) stacktop = (char *) (pd - 1); #endif #ifdef NEED_SEPARATE_REGISTER_STACK *stack = pd->stackblock; *stacksize = stacktop - *stack; #elif defined _STACK_GROWS_DOWN *stack = stacktop; #elif defined _STACK_GROWS_UP *stack = pd->stackblock; assert (*stack > 0); #endif return 0; } void internal_function __deallocate_stack (struct pthread *pd) { lll_lock (stack_cache_lock, LLL_PRIVATE); /* Remove the thread from the list of threads with user defined stacks. */ stack_list_del (&pd->list); /* Not much to do. Just free the mmap()ed memory. Note that we do not reset the 'used' flag in the 'tid' field. This is done by the kernel. If no thread has been created yet this field is still zero. */ if (__builtin_expect (! pd->user_stack, 1)) (void) queue_stack (pd); else /* Free the memory associated with the ELF TLS. */ _dl_deallocate_tls (TLS_TPADJ (pd), false); lll_unlock (stack_cache_lock, LLL_PRIVATE); } int internal_function __make_stacks_executable (void **stack_endp) { /* First the main thread's stack. */ int err = EPERM; if (err != 0) return err; #ifdef NEED_SEPARATE_REGISTER_STACK const size_t pagemask = ~(__getpagesize () - 1); #endif lll_lock (stack_cache_lock, LLL_PRIVATE); list_t *runp; list_for_each (runp, &stack_used) { err = change_stack_perm (list_entry (runp, struct pthread, list) #ifdef NEED_SEPARATE_REGISTER_STACK , pagemask #endif ); if (err != 0) break; } /* Also change the permission for the currently unused stacks. This might be wasted time but better spend it here than adding a check in the fast path. */ if (err == 0) list_for_each (runp, &stack_cache) { err = change_stack_perm (list_entry (runp, struct pthread, list) #ifdef NEED_SEPARATE_REGISTER_STACK , pagemask #endif ); if (err != 0) break; } lll_unlock (stack_cache_lock, LLL_PRIVATE); return err; } /* In case of a fork() call the memory allocation in the child will be the same but only one thread is running. All stacks except that of the one running thread are not used anymore. We have to recycle them. */ void __reclaim_stacks (void) { struct pthread *self = (struct pthread *) THREAD_SELF; /* No locking necessary. The caller is the only stack in use. But we have to be aware that we might have interrupted a list operation. */ if (in_flight_stack != 0) { bool add_p = in_flight_stack & 1; list_t *elem = (list_t *)(uintptr_t)(in_flight_stack & ~UINTMAX_C (1)); if (add_p) { /* We always add at the beginning of the list. So in this case we only need to check the beginning of these lists. */ int check_list (list_t *l) { if (l->next->prev != l) { assert (l->next->prev == elem); elem->next = l->next; elem->prev = l; l->next = elem; return 1; } return 0; } if (check_list (&stack_used) == 0) (void) check_list (&stack_cache); } else { /* We can simply always replay the delete operation. */ elem->next->prev = elem->prev; elem->prev->next = elem->next; } } /* Mark all stacks except the still running one as free. */ list_t *runp; list_for_each (runp, &stack_used) { struct pthread *curp = list_entry (runp, struct pthread, list); if (curp != self) { /* This marks the stack as free. */ curp->tid = 0; /* The PID field must be initialized for the new process. */ curp->pid = self->pid; /* Account for the size of the stack. */ stack_cache_actsize += curp->stackblock_size; if (curp->specific_used) { /* Clear the thread-specific data. */ memset (curp->specific_1stblock, '\0', sizeof (curp->specific_1stblock)); curp->specific_used = false; size_t cnt; for (cnt = 1; cnt < PTHREAD_KEY_1STLEVEL_SIZE; ++cnt) if (curp->specific[cnt] != NULL) { memset (curp->specific[cnt], '\0', sizeof (curp->specific_1stblock)); /* We have allocated the block which we do not free here so re-set the bit. */ curp->specific_used = true; } } } } /* Reset the PIDs in any cached stacks. */ list_for_each (runp, &stack_cache) { struct pthread *curp = list_entry (runp, struct pthread, list); curp->pid = self->pid; } /* Add the stack of all running threads to the cache. */ list_splice (&stack_used, &stack_cache); /* Remove the entry for the current thread to from the cache list and add it to the list of running threads. Which of the two lists is decided by the user_stack flag. */ stack_list_del (&self->list); /* Re-initialize the lists for all the threads. */ INIT_LIST_HEAD (&stack_used); INIT_LIST_HEAD (&__stack_user); if (__builtin_expect (THREAD_GETMEM (self, user_stack), 0)) list_add (&self->list, &__stack_user); else list_add (&self->list, &stack_used); /* There is one thread running. */ __nptl_nthreads = 1; in_flight_stack = 0; /* Initialize the lock. */ stack_cache_lock = LLL_LOCK_INITIALIZER; } #if HP_TIMING_AVAIL # undef __find_thread_by_id /* Find a thread given the thread ID. */ attribute_hidden struct pthread * __find_thread_by_id (pid_t tid) { struct pthread *result = NULL; lll_lock (stack_cache_lock, LLL_PRIVATE); /* Iterate over the list with system-allocated threads first. */ list_t *runp; list_for_each (runp, &stack_used) { struct pthread *curp; curp = list_entry (runp, struct pthread, list); if (curp->tid == tid) { result = curp; goto out; } } /* Now the list with threads using user-allocated stacks. */ list_for_each (runp, &__stack_user) { struct pthread *curp; curp = list_entry (runp, struct pthread, list); if (curp->tid == tid) { result = curp; goto out; } } out: lll_unlock (stack_cache_lock, LLL_PRIVATE); return result; } #endif static void internal_function setxid_mark_thread (struct xid_command *cmdp, struct pthread *t) { int ch; /* Don't let the thread exit before the setxid handler runs. */ t->setxid_futex = 0; do { ch = t->cancelhandling; /* If the thread is exiting right now, ignore it. */ if ((ch & EXITING_BITMASK) != 0) return; } while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling, ch | SETXID_BITMASK, ch)); } static void internal_function setxid_unmark_thread (struct xid_command *cmdp, struct pthread *t) { int ch; do { ch = t->cancelhandling; if ((ch & SETXID_BITMASK) == 0) return; } while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling, ch & ~SETXID_BITMASK, ch)); /* Release the futex just in case. */ t->setxid_futex = 1; lll_futex_wake (&t->setxid_futex, 1, LLL_PRIVATE); } static int internal_function setxid_signal_thread (struct xid_command *cmdp, struct pthread *t) { if ((t->cancelhandling & SETXID_BITMASK) == 0) return 0; int val; INTERNAL_SYSCALL_DECL (err); #if defined (__ASSUME_TGKILL) && __ASSUME_TGKILL val = INTERNAL_SYSCALL (tgkill, err, 3, THREAD_GETMEM (THREAD_SELF, pid), t->tid, SIGSETXID); #else # ifdef __NR_tgkill val = INTERNAL_SYSCALL (tgkill, err, 3, THREAD_GETMEM (THREAD_SELF, pid), t->tid, SIGSETXID); if (INTERNAL_SYSCALL_ERROR_P (val, err) && INTERNAL_SYSCALL_ERRNO (val, err) == ENOSYS) # endif val = INTERNAL_SYSCALL (tkill, err, 2, t->tid, SIGSETXID); #endif /* If this failed, it must have had not started yet or else exited. */ if (!INTERNAL_SYSCALL_ERROR_P (val, err)) { atomic_increment (&cmdp->cntr); return 1; } else return 0; } int attribute_hidden __nptl_setxid (struct xid_command *cmdp) { int signalled; int result; lll_lock (stack_cache_lock, LLL_PRIVATE); __xidcmd = cmdp; cmdp->cntr = 0; struct pthread *self = THREAD_SELF; /* Iterate over the list with system-allocated threads first. */ list_t *runp; list_for_each (runp, &stack_used) { struct pthread *t = list_entry (runp, struct pthread, list); if (t == self) continue; setxid_mark_thread (cmdp, t); } /* Now the list with threads using user-allocated stacks. */ list_for_each (runp, &__stack_user) { struct pthread *t = list_entry (runp, struct pthread, list); if (t == self) continue; setxid_mark_thread (cmdp, t); } /* Iterate until we don't succeed in signalling anyone. That means we have gotten all running threads, and their children will be automatically correct once started. */ do { signalled = 0; list_for_each (runp, &stack_used) { struct pthread *t = list_entry (runp, struct pthread, list); if (t == self) continue; signalled += setxid_signal_thread (cmdp, t); } list_for_each (runp, &__stack_user) { struct pthread *t = list_entry (runp, struct pthread, list); if (t == self) continue; signalled += setxid_signal_thread (cmdp, t); } int cur = cmdp->cntr; while (cur != 0) { lll_futex_wait (&cmdp->cntr, cur, LLL_PRIVATE); cur = cmdp->cntr; } } while (signalled != 0); /* Clean up flags, so that no thread blocks during exit waiting for a signal which will never come. */ list_for_each (runp, &stack_used) { struct pthread *t = list_entry (runp, struct pthread, list); if (t == self) continue; setxid_unmark_thread (cmdp, t); } list_for_each (runp, &__stack_user) { struct pthread *t = list_entry (runp, struct pthread, list); if (t == self) continue; setxid_unmark_thread (cmdp, t); } /* This must be last, otherwise the current thread might not have permissions to send SIGSETXID syscall to the other threads. */ INTERNAL_SYSCALL_DECL (err); result = INTERNAL_SYSCALL_NCS (cmdp->syscall_no, err, 3, cmdp->id[0], cmdp->id[1], cmdp->id[2]); if (INTERNAL_SYSCALL_ERROR_P (result, err)) { __set_errno (INTERNAL_SYSCALL_ERRNO (result, err)); result = -1; } lll_unlock (stack_cache_lock, LLL_PRIVATE); return result; } static inline void __attribute__((always_inline)) init_one_static_tls (struct pthread *curp, struct link_map *map) { dtv_t *dtv = GET_DTV (TLS_TPADJ (curp)); # if defined(TLS_TCB_AT_TP) void *dest = (char *) curp - map->l_tls_offset; # elif defined(TLS_DTV_AT_TP) void *dest = (char *) curp + map->l_tls_offset + TLS_PRE_TCB_SIZE; # else # error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined" # endif /* Fill in the DTV slot so that a later LD/GD access will find it. */ dtv[map->l_tls_modid].pointer.val = dest; dtv[map->l_tls_modid].pointer.is_static = true; /* Initialize the memory. */ memset (mempcpy (dest, map->l_tls_initimage, map->l_tls_initimage_size), '\0', map->l_tls_blocksize - map->l_tls_initimage_size); } void attribute_hidden __pthread_init_static_tls (struct link_map *map) { lll_lock (stack_cache_lock, LLL_PRIVATE); /* Iterate over the list with system-allocated threads first. */ list_t *runp; list_for_each (runp, &stack_used) init_one_static_tls (list_entry (runp, struct pthread, list), map); /* Now the list with threads using user-allocated stacks. */ list_for_each (runp, &__stack_user) init_one_static_tls (list_entry (runp, struct pthread, list), map); lll_unlock (stack_cache_lock, LLL_PRIVATE); } void attribute_hidden __wait_lookup_done (void) { lll_lock (stack_cache_lock, LLL_PRIVATE); struct pthread *self = THREAD_SELF; /* Iterate over the list with system-allocated threads first. */ list_t *runp; list_for_each (runp, &stack_used) { struct pthread *t = list_entry (runp, struct pthread, list); if (t == self || t->header.gscope_flag == THREAD_GSCOPE_FLAG_UNUSED) continue; int *const gscope_flagp = &t->header.gscope_flag; /* We have to wait until this thread is done with the global scope. First tell the thread that we are waiting and possibly have to be woken. */ if (atomic_compare_and_exchange_bool_acq (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT, THREAD_GSCOPE_FLAG_USED)) continue; do lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT, LLL_PRIVATE); while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT); } /* Now the list with threads using user-allocated stacks. */ list_for_each (runp, &__stack_user) { struct pthread *t = list_entry (runp, struct pthread, list); if (t == self || t->header.gscope_flag == THREAD_GSCOPE_FLAG_UNUSED) continue; int *const gscope_flagp = &t->header.gscope_flag; /* We have to wait until this thread is done with the global scope. First tell the thread that we are waiting and possibly have to be woken. */ if (atomic_compare_and_exchange_bool_acq (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT, THREAD_GSCOPE_FLAG_USED)) continue; do lll_futex_wait (gscope_flagp, THREAD_GSCOPE_FLAG_WAIT, LLL_PRIVATE); while (*gscope_flagp == THREAD_GSCOPE_FLAG_WAIT); } lll_unlock (stack_cache_lock, LLL_PRIVATE); } |