1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- 4-- -- 5-- S Y S T E M . T A S K I N G . I N I T I A L I Z A T I O N -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992-2019, Free Software Foundation, Inc. -- 10-- -- 11-- GNARL is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNARL was developed by the GNARL team at Florida State University. -- 28-- Extensive contributions were provided by Ada Core Technologies, Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32pragma Style_Checks (All_Checks); 33-- Turn off subprogram alpha ordering check, since we group soft link bodies 34-- and dummy soft link bodies together separately in this unit. 35 36pragma Polling (Off); 37-- Turn polling off for this package. We don't need polling during any of the 38-- routines in this package, and more to the point, if we try to poll it can 39-- cause infinite loops. 40 41with System.Task_Primitives; 42with System.Task_Primitives.Operations; 43with System.Soft_Links; 44with System.Soft_Links.Tasking; 45with System.Tasking.Debug; 46with System.Tasking.Task_Attributes; 47with System.Parameters; 48 49with System.Secondary_Stack; 50pragma Elaborate_All (System.Secondary_Stack); 51pragma Unreferenced (System.Secondary_Stack); 52-- Make sure the body of Secondary_Stack is elaborated before calling 53-- Init_Tasking_Soft_Links. See comments for this routine for explanation. 54 55package body System.Tasking.Initialization is 56 57 package STPO renames System.Task_Primitives.Operations; 58 package SSL renames System.Soft_Links; 59 60 use Parameters; 61 use Task_Primitives.Operations; 62 63 Global_Task_Lock : aliased System.Task_Primitives.RTS_Lock; 64 -- This is a global lock; it is used to execute in mutual exclusion from 65 -- all other tasks. It is only used by Task_Lock, Task_Unlock, and 66 -- Final_Task_Unlock. 67 68 ---------------------------------------------------------------------- 69 -- Tasking versions of some services needed by non-tasking programs -- 70 ---------------------------------------------------------------------- 71 72 procedure Abort_Defer; 73 -- NON-INLINE versions without Self_ID for soft links 74 75 procedure Abort_Undefer; 76 -- NON-INLINE versions without Self_ID for soft links 77 78 procedure Task_Lock; 79 -- Locks out other tasks. Preceding a section of code by Task_Lock and 80 -- following it by Task_Unlock creates a critical region. This is used 81 -- for ensuring that a region of non-tasking code (such as code used to 82 -- allocate memory) is tasking safe. Note that it is valid for calls to 83 -- Task_Lock/Task_Unlock to be nested, and this must work properly, i.e. 84 -- only the corresponding outer level Task_Unlock will actually unlock. 85 86 procedure Task_Unlock; 87 -- Releases lock previously set by call to Task_Lock. In the nested case, 88 -- all nested locks must be released before other tasks competing for the 89 -- tasking lock are released. 90 91 function Get_Current_Excep return SSL.EOA; 92 -- Task-safe version of SSL.Get_Current_Excep 93 94 function Task_Name return String; 95 -- Returns current task's name 96 97 ------------------------ 98 -- Local Subprograms -- 99 ------------------------ 100 101 ---------------------------- 102 -- Tasking Initialization -- 103 ---------------------------- 104 105 procedure Init_RTS; 106 -- This procedure completes the initialization of the GNARL. The first part 107 -- of the initialization is done in the body of System.Tasking. It consists 108 -- of initializing global locks, and installing tasking versions of certain 109 -- operations used by the compiler. Init_RTS is called during elaboration. 110 111 -------------------------- 112 -- Change_Base_Priority -- 113 -------------------------- 114 115 -- Call only with abort deferred and holding Self_ID locked 116 117 procedure Change_Base_Priority (T : Task_Id) is 118 begin 119 if T.Common.Base_Priority /= T.New_Base_Priority then 120 T.Common.Base_Priority := T.New_Base_Priority; 121 Set_Priority (T, T.Common.Base_Priority); 122 end if; 123 end Change_Base_Priority; 124 125 ------------------------ 126 -- Check_Abort_Status -- 127 ------------------------ 128 129 function Check_Abort_Status return Integer is 130 Self_ID : constant Task_Id := Self; 131 begin 132 if Self_ID /= null 133 and then Self_ID.Deferral_Level = 0 134 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level 135 then 136 return 1; 137 else 138 return 0; 139 end if; 140 end Check_Abort_Status; 141 142 ----------------- 143 -- Defer_Abort -- 144 ----------------- 145 146 procedure Defer_Abort (Self_ID : Task_Id) is 147 begin 148 if No_Abort then 149 return; 150 end if; 151 152 pragma Assert (Self_ID.Deferral_Level = 0); 153 154 -- pragma Assert 155 -- (Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level); 156 157 -- The above check has been useful in detecting mismatched defer/undefer 158 -- pairs. You may uncomment it when testing on systems that support 159 -- preemptive abort. 160 161 -- If the OS supports preemptive abort (e.g. pthread_kill), it should 162 -- have happened already. A problem is with systems that do not support 163 -- preemptive abort, and so rely on polling. On such systems we may get 164 -- false failures of the assertion, since polling for pending abort does 165 -- no occur until the abort undefer operation. 166 167 -- Even on systems that only poll for abort, the assertion may be useful 168 -- for catching missed abort completion polling points. The operations 169 -- that undefer abort poll for pending aborts. This covers most of the 170 -- places where the core Ada semantics require abort to be caught, 171 -- without any special attention. However, this generally happens on 172 -- exit from runtime system call, which means a pending abort will not 173 -- be noticed on the way into the runtime system. We considered adding a 174 -- check for pending aborts at this point, but chose not to, because of 175 -- the overhead. Instead, we searched for RTS calls where abort 176 -- completion is required and a task could go farther than Ada allows 177 -- before undeferring abort; we then modified the code to ensure the 178 -- abort would be detected. 179 180 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 181 end Defer_Abort; 182 183 -------------------------- 184 -- Defer_Abort_Nestable -- 185 -------------------------- 186 187 procedure Defer_Abort_Nestable (Self_ID : Task_Id) is 188 begin 189 if No_Abort then 190 return; 191 end if; 192 193 -- The following assertion is by default disabled. See the comment in 194 -- Defer_Abort on the situations in which it may be useful to uncomment 195 -- this assertion and enable the test. 196 197 -- pragma Assert 198 -- (Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level or else 199 -- Self_ID.Deferral_Level > 0); 200 201 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 202 end Defer_Abort_Nestable; 203 204 ----------------- 205 -- Abort_Defer -- 206 ----------------- 207 208 procedure Abort_Defer is 209 Self_ID : Task_Id; 210 begin 211 if No_Abort then 212 return; 213 end if; 214 215 Self_ID := STPO.Self; 216 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 217 end Abort_Defer; 218 219 ----------------------- 220 -- Get_Current_Excep -- 221 ----------------------- 222 223 function Get_Current_Excep return SSL.EOA is 224 begin 225 return STPO.Self.Common.Compiler_Data.Current_Excep'Access; 226 end Get_Current_Excep; 227 228 ----------------------- 229 -- Do_Pending_Action -- 230 ----------------------- 231 232 -- Call only when holding no locks 233 234 procedure Do_Pending_Action (Self_ID : Task_Id) is 235 236 begin 237 pragma Assert (Self_ID = Self and then Self_ID.Deferral_Level = 0); 238 239 -- Needs loop to recheck for pending action in case a new one occurred 240 -- while we had abort deferred below. 241 242 loop 243 -- Temporarily defer abort so that we can lock Self_ID 244 245 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1; 246 247 if Single_Lock then 248 Lock_RTS; 249 end if; 250 251 Write_Lock (Self_ID); 252 Self_ID.Pending_Action := False; 253 Unlock (Self_ID); 254 255 if Single_Lock then 256 Unlock_RTS; 257 end if; 258 259 -- Restore the original Deferral value 260 261 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 262 263 if not Self_ID.Pending_Action then 264 if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then 265 if not Self_ID.Aborting then 266 Self_ID.Aborting := True; 267 pragma Debug 268 (Debug.Trace (Self_ID, "raise Abort_Signal", 'B')); 269 raise Standard'Abort_Signal; 270 271 pragma Assert (not Self_ID.ATC_Hack); 272 273 elsif Self_ID.ATC_Hack then 274 275 -- The solution really belongs in the Abort_Signal handler 276 -- for async. entry calls. The present hack is very 277 -- fragile. It relies that the very next point after 278 -- Exit_One_ATC_Level at which the task becomes abortable 279 -- will be the call to Undefer_Abort in the 280 -- Abort_Signal handler. 281 282 Self_ID.ATC_Hack := False; 283 284 pragma Debug 285 (Debug.Trace 286 (Self_ID, "raise Abort_Signal (ATC hack)", 'B')); 287 raise Standard'Abort_Signal; 288 end if; 289 end if; 290 291 return; 292 end if; 293 end loop; 294 end Do_Pending_Action; 295 296 ----------------------- 297 -- Final_Task_Unlock -- 298 ----------------------- 299 300 -- This version is only for use in Terminate_Task, when the task is 301 -- relinquishing further rights to its own ATCB. 302 303 -- There is a very interesting potential race condition there, where the 304 -- old task may run concurrently with a new task that is allocated the old 305 -- tasks (now reused) ATCB. The critical thing here is to not make any 306 -- reference to the ATCB after the lock is released. See also comments on 307 -- Terminate_Task and Unlock. 308 309 procedure Final_Task_Unlock (Self_ID : Task_Id) is 310 begin 311 pragma Assert (Self_ID.Common.Global_Task_Lock_Nesting = 1); 312 Unlock (Global_Task_Lock'Access, Global_Lock => True); 313 end Final_Task_Unlock; 314 315 -------------- 316 -- Init_RTS -- 317 -------------- 318 319 procedure Init_RTS is 320 Self_Id : Task_Id; 321 begin 322 Tasking.Initialize; 323 324 -- Terminate run time (regular vs restricted) specific initialization 325 -- of the environment task. 326 327 Self_Id := Environment_Task; 328 Self_Id.Master_Of_Task := Environment_Task_Level; 329 Self_Id.Master_Within := Self_Id.Master_Of_Task + 1; 330 331 for L in Self_Id.Entry_Calls'Range loop 332 Self_Id.Entry_Calls (L).Self := Self_Id; 333 Self_Id.Entry_Calls (L).Level := L; 334 end loop; 335 336 Self_Id.Awake_Count := 1; 337 Self_Id.Alive_Count := 1; 338 339 -- Normally, a task starts out with internal master nesting level one 340 -- larger than external master nesting level. It is incremented to one 341 -- by Enter_Master, which is called in the task body only if the 342 -- compiler thinks the task may have dependent tasks. There is no 343 -- corresponding call to Enter_Master for the environment task, so we 344 -- would need to increment it to 2 here. Instead, we set it to 3. By 345 -- doing this we reserve the level 2 for server tasks of the runtime 346 -- system. The environment task does not need to wait for these server 347 348 Self_Id.Master_Within := Library_Task_Level; 349 350 -- Initialize lock used to implement mutual exclusion between all tasks 351 352 Initialize_Lock (Global_Task_Lock'Access, STPO.Global_Task_Level); 353 354 -- Notify that the tasking run time has been elaborated so that 355 -- the tasking version of the soft links can be used. 356 357 if not No_Abort then 358 SSL.Abort_Defer := Abort_Defer'Access; 359 SSL.Abort_Undefer := Abort_Undefer'Access; 360 end if; 361 362 SSL.Lock_Task := Task_Lock'Access; 363 SSL.Unlock_Task := Task_Unlock'Access; 364 SSL.Check_Abort_Status := Check_Abort_Status'Access; 365 SSL.Task_Name := Task_Name'Access; 366 SSL.Get_Current_Excep := Get_Current_Excep'Access; 367 368 -- Initialize the tasking soft links (if not done yet) that are common 369 -- to the full and the restricted run times. 370 371 SSL.Tasking.Init_Tasking_Soft_Links; 372 373 -- Abort is deferred in a new ATCB, so we need to undefer abort at this 374 -- stage to make the environment task abortable. 375 376 Undefer_Abort (Environment_Task); 377 end Init_RTS; 378 379 --------------------------- 380 -- Locked_Abort_To_Level-- 381 --------------------------- 382 383 -- Abort a task to the specified ATC nesting level. 384 -- Call this only with T locked. 385 386 -- An earlier version of this code contained a call to Wakeup. That should 387 -- not be necessary here, if Abort_Task is implemented correctly, since 388 -- Abort_Task should include the effect of Wakeup. However, the above call 389 -- was in earlier versions of this file, and at least for some targets 390 -- Abort_Task has not been doing Wakeup. It should not hurt to uncomment 391 -- the above call, until the error is corrected for all targets. 392 393 -- See extended comments in package body System.Tasking.Abort for the 394 -- overall design of the implementation of task abort. 395 -- ??? there is no such package ??? 396 397 -- If the task is sleeping it will be in an abort-deferred region, and will 398 -- not have Abort_Signal raised by Abort_Task. Such an "abort deferral" is 399 -- just to protect the RTS internals, and not necessarily required to 400 -- enforce Ada semantics. Abort_Task should wake the task up and let it 401 -- decide if it wants to complete the aborted construct immediately. 402 403 -- Note that the effect of the low-level Abort_Task is not persistent. 404 -- If the target task is not blocked, this wakeup will be missed. 405 406 -- We don't bother calling Abort_Task if this task is aborting itself, 407 -- since we are inside the RTS and have abort deferred. Similarly, We don't 408 -- bother to call Abort_Task if T is terminated, since there is no need to 409 -- abort a terminated task, and it could be dangerous to try if the task 410 -- has stopped executing. 411 412 -- Note that an earlier version of this code had some false reasoning about 413 -- being able to reliably wake up a task that had suspended on a blocking 414 -- system call that does not atomically release the task's lock (e.g., UNIX 415 -- nanosleep, which we once thought could be used to implement delays). 416 -- That still left the possibility of missed wakeups. 417 418 -- We cannot safely call Vulnerable_Complete_Activation here, since that 419 -- requires locking Self_ID.Parent. The anti-deadlock lock ordering rules 420 -- would then require us to release the lock on Self_ID first, which would 421 -- create a timing window for other tasks to lock Self_ID. This is 422 -- significant for tasks that may be aborted before their execution can 423 -- enter the task body, and so they do not get a chance to call 424 -- Complete_Task. The actual work for this case is done in Terminate_Task. 425 426 procedure Locked_Abort_To_Level 427 (Self_ID : Task_Id; 428 T : Task_Id; 429 L : ATC_Level_Base) 430 is 431 begin 432 if not T.Aborting and then T /= Self_ID then 433 case T.Common.State is 434 when Terminated 435 | Unactivated 436 => 437 pragma Assert (False); 438 null; 439 440 when Activating 441 | Runnable 442 => 443 if T.ATC_Nesting_Level > Level_No_ATC_Occurring then 444 -- This scenario occurs when an asynchronous protected entry 445 -- call is canceled during a requeue with abort. 446 447 T.Entry_Calls 448 (T.ATC_Nesting_Level).Cancellation_Attempted := True; 449 end if; 450 451 when Interrupt_Server_Blocked_On_Event_Flag => 452 null; 453 454 when AST_Server_Sleep 455 | Async_Select_Sleep 456 | Delay_Sleep 457 | Interrupt_Server_Blocked_Interrupt_Sleep 458 | Interrupt_Server_Idle_Sleep 459 | Timer_Server_Sleep 460 => 461 Wakeup (T, T.Common.State); 462 463 when Acceptor_Delay_Sleep 464 | Acceptor_Sleep 465 => 466 T.Open_Accepts := null; 467 Wakeup (T, T.Common.State); 468 469 when Entry_Caller_Sleep => 470 pragma Assert (T.ATC_Nesting_Level > Level_No_ATC_Occurring); 471 472 T.Entry_Calls 473 (T.ATC_Nesting_Level).Cancellation_Attempted := True; 474 Wakeup (T, T.Common.State); 475 476 when Activator_Sleep 477 | Asynchronous_Hold 478 | Master_Completion_Sleep 479 | Master_Phase_2_Sleep 480 => 481 null; 482 end case; 483 end if; 484 485 if T.Pending_ATC_Level > L then 486 T.Pending_ATC_Level := L; 487 T.Pending_Action := True; 488 489 if L = Level_Completed_Task then 490 T.Callable := False; 491 end if; 492 493 -- This prevents aborted task from accepting calls 494 495 if T.Aborting then 496 497 -- The test above is just a heuristic, to reduce wasteful 498 -- calls to Abort_Task. We are holding T locked, and this 499 -- value will not be set to False except with T also locked, 500 -- inside Exit_One_ATC_Level, so we should not miss wakeups. 501 502 if T.Common.State = Acceptor_Sleep 503 or else 504 T.Common.State = Acceptor_Delay_Sleep 505 then 506 T.Open_Accepts := null; 507 end if; 508 509 elsif T /= Self_ID and then 510 (T.Common.State = Runnable 511 or else T.Common.State = Interrupt_Server_Blocked_On_Event_Flag) 512 513 -- The task is blocked on a system call waiting for the 514 -- completion event. In this case Abort_Task may need to take 515 -- special action in order to succeed. 516 517 then 518 Abort_Task (T); 519 end if; 520 end if; 521 end Locked_Abort_To_Level; 522 523 -------------------------------- 524 -- Remove_From_All_Tasks_List -- 525 -------------------------------- 526 527 procedure Remove_From_All_Tasks_List (T : Task_Id) is 528 C : Task_Id; 529 Previous : Task_Id; 530 531 begin 532 pragma Debug 533 (Debug.Trace (Self, "Remove_From_All_Tasks_List", 'C')); 534 535 Previous := Null_Task; 536 C := All_Tasks_List; 537 while C /= Null_Task loop 538 if C = T then 539 if Previous = Null_Task then 540 All_Tasks_List := All_Tasks_List.Common.All_Tasks_Link; 541 else 542 Previous.Common.All_Tasks_Link := C.Common.All_Tasks_Link; 543 end if; 544 545 return; 546 end if; 547 548 Previous := C; 549 C := C.Common.All_Tasks_Link; 550 end loop; 551 552 pragma Assert (False); 553 end Remove_From_All_Tasks_List; 554 555 --------------- 556 -- Task_Lock -- 557 --------------- 558 559 procedure Task_Lock (Self_ID : Task_Id) is 560 begin 561 Self_ID.Common.Global_Task_Lock_Nesting := 562 Self_ID.Common.Global_Task_Lock_Nesting + 1; 563 564 if Self_ID.Common.Global_Task_Lock_Nesting = 1 then 565 Defer_Abort_Nestable (Self_ID); 566 Write_Lock (Global_Task_Lock'Access, Global_Lock => True); 567 end if; 568 end Task_Lock; 569 570 procedure Task_Lock is 571 begin 572 Task_Lock (STPO.Self); 573 end Task_Lock; 574 575 --------------- 576 -- Task_Name -- 577 --------------- 578 579 function Task_Name return String is 580 Self_Id : constant Task_Id := STPO.Self; 581 begin 582 return Self_Id.Common.Task_Image (1 .. Self_Id.Common.Task_Image_Len); 583 end Task_Name; 584 585 ----------------- 586 -- Task_Unlock -- 587 ----------------- 588 589 procedure Task_Unlock (Self_ID : Task_Id) is 590 begin 591 pragma Assert (Self_ID.Common.Global_Task_Lock_Nesting > 0); 592 Self_ID.Common.Global_Task_Lock_Nesting := 593 Self_ID.Common.Global_Task_Lock_Nesting - 1; 594 595 if Self_ID.Common.Global_Task_Lock_Nesting = 0 then 596 Unlock (Global_Task_Lock'Access, Global_Lock => True); 597 Undefer_Abort_Nestable (Self_ID); 598 end if; 599 end Task_Unlock; 600 601 procedure Task_Unlock is 602 begin 603 Task_Unlock (STPO.Self); 604 end Task_Unlock; 605 606 ------------------- 607 -- Undefer_Abort -- 608 ------------------- 609 610 -- Precondition : Self does not hold any locks 611 612 -- Undefer_Abort is called on any abort completion point (aka. 613 -- synchronization point). It performs the following actions if they 614 -- are pending: (1) change the base priority, (2) abort the task. 615 616 -- The priority change has to occur before abort. Otherwise, it would 617 -- take effect no earlier than the next abort completion point. 618 619 procedure Undefer_Abort (Self_ID : Task_Id) is 620 begin 621 if No_Abort then 622 return; 623 end if; 624 625 pragma Assert (Self_ID.Deferral_Level = 1); 626 627 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 628 629 if Self_ID.Deferral_Level = 0 then 630 pragma Assert (Check_No_Locks (Self_ID)); 631 632 if Self_ID.Pending_Action then 633 Do_Pending_Action (Self_ID); 634 end if; 635 end if; 636 end Undefer_Abort; 637 638 ---------------------------- 639 -- Undefer_Abort_Nestable -- 640 ---------------------------- 641 642 -- An earlier version would re-defer abort if an abort is in progress. 643 -- Then, we modified the effect of the raise statement so that it defers 644 -- abort until control reaches a handler. That was done to prevent 645 -- "skipping over" a handler if another asynchronous abort occurs during 646 -- the propagation of the abort to the handler. 647 648 -- There has been talk of reversing that decision, based on a newer 649 -- implementation of exception propagation. Care must be taken to evaluate 650 -- how such a change would interact with the above code and all the places 651 -- where abort-deferral is used to bridge over critical transitions, such 652 -- as entry to the scope of a region with a finalizer and entry into the 653 -- body of an accept-procedure. 654 655 procedure Undefer_Abort_Nestable (Self_ID : Task_Id) is 656 begin 657 if No_Abort then 658 return; 659 end if; 660 661 pragma Assert (Self_ID.Deferral_Level > 0); 662 663 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 664 665 if Self_ID.Deferral_Level = 0 then 666 667 pragma Assert (Check_No_Locks (Self_ID)); 668 669 if Self_ID.Pending_Action then 670 Do_Pending_Action (Self_ID); 671 end if; 672 end if; 673 end Undefer_Abort_Nestable; 674 675 ------------------- 676 -- Abort_Undefer -- 677 ------------------- 678 679 procedure Abort_Undefer is 680 Self_ID : Task_Id; 681 begin 682 if No_Abort then 683 return; 684 end if; 685 686 Self_ID := STPO.Self; 687 688 if Self_ID.Deferral_Level = 0 then 689 690 -- In case there are different views on whether Abort is supported 691 -- between the expander and the run time, we may end up with 692 -- Self_ID.Deferral_Level being equal to zero, when called from 693 -- the procedure created by the expander that corresponds to a 694 -- task body. In this case, there's nothing to be done. 695 696 -- See related code in System.Tasking.Stages.Create_Task resetting 697 -- Deferral_Level when System.Restrictions.Abort_Allowed is False. 698 699 return; 700 end if; 701 702 pragma Assert (Self_ID.Deferral_Level > 0); 703 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1; 704 705 if Self_ID.Deferral_Level = 0 then 706 pragma Assert (Check_No_Locks (Self_ID)); 707 708 if Self_ID.Pending_Action then 709 Do_Pending_Action (Self_ID); 710 end if; 711 end if; 712 end Abort_Undefer; 713 714 -------------------------- 715 -- Wakeup_Entry_Caller -- 716 -------------------------- 717 718 -- This is called at the end of service of an entry call, to abort the 719 -- caller if he is in an abortable part, and to wake up the caller if it 720 -- is on Entry_Caller_Sleep. It assumes that the call is already off-queue. 721 722 -- (This enforces the rule that a task must be off-queue if its state is 723 -- Done or Cancelled.) Call it holding the lock of Entry_Call.Self. 724 725 -- Timed_Call or Simple_Call: 726 -- The caller is waiting on Entry_Caller_Sleep, in 727 -- Wait_For_Completion, or Wait_For_Completion_With_Timeout. 728 729 -- Conditional_Call: 730 -- The caller might be in Wait_For_Completion, 731 -- waiting for a rendezvous (possibly requeued without abort) 732 -- to complete. 733 734 -- Asynchronous_Call: 735 -- The caller may be executing in the abortable part o 736 -- an async. select, or on a time delay, 737 -- if Entry_Call.State >= Was_Abortable. 738 739 procedure Wakeup_Entry_Caller 740 (Self_ID : Task_Id; 741 Entry_Call : Entry_Call_Link; 742 New_State : Entry_Call_State) 743 is 744 Caller : constant Task_Id := Entry_Call.Self; 745 746 begin 747 pragma Debug (Debug.Trace 748 (Self_ID, "Wakeup_Entry_Caller", 'E', Caller)); 749 pragma Assert (New_State = Done or else New_State = Cancelled); 750 751 pragma Assert (Caller.Common.State /= Unactivated); 752 753 Entry_Call.State := New_State; 754 755 if Entry_Call.Mode = Asynchronous_Call then 756 757 -- Abort the caller in his abortable part, but do so only if call has 758 -- been queued abortably. 759 760 if Entry_Call.State >= Was_Abortable or else New_State = Done then 761 Locked_Abort_To_Level (Self_ID, Caller, Entry_Call.Level - 1); 762 end if; 763 764 elsif Caller.Common.State = Entry_Caller_Sleep then 765 Wakeup (Caller, Entry_Caller_Sleep); 766 end if; 767 end Wakeup_Entry_Caller; 768 769 ------------------------- 770 -- Finalize_Attributes -- 771 ------------------------- 772 773 procedure Finalize_Attributes (T : Task_Id) is 774 Attr : Atomic_Address; 775 776 begin 777 for J in T.Attributes'Range loop 778 Attr := T.Attributes (J); 779 780 if Attr /= 0 and then Task_Attributes.Require_Finalization (J) then 781 Task_Attributes.To_Attribute (Attr).Free (Attr); 782 T.Attributes (J) := 0; 783 end if; 784 end loop; 785 end Finalize_Attributes; 786 787begin 788 Init_RTS; 789end System.Tasking.Initialization; 790