1 ------------------------------------------------------------------------------
3 -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
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 --
9 -- Copyright (C) 1992-2005, Free Software Foundation, Inc. --
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 2, or (at your option) any later ver- --
14 -- sion. GNARL 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNARL; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNARL was developed by the GNARL team at Florida State University. --
30 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
32 ------------------------------------------------------------------------------
34 pragma Style_Checks (All_Checks);
35 -- Turn off subprogram alpha ordering check, since we group soft link
36 -- bodies and dummy soft link bodies together separately in this unit.
39 -- Turn polling off for this package. We don't need polling during any
40 -- of the routines in this package, and more to the point, if we try
41 -- to poll it can cause infinite loops.
44 -- Used for Exception_Occurrence_Access
47 pragma Elaborate_All (System.Tasking);
48 -- Ensure that the first step initializations have been performed
50 with System.Task_Primitives;
53 with System.Task_Primitives.Operations;
54 -- Used for Set_Priority
59 with System.Soft_Links;
60 -- Used for the non-tasking routines (*_NT) that refer to global data.
61 -- They are needed here before the tasking run time has been elaborated.
63 with System.Soft_Links.Tasking;
64 -- Used for Init_Tasking_Soft_Links
66 with System.Tasking.Debug;
69 with System.Stack_Checking;
71 with System.Parameters;
72 -- used for Single_Lock
74 package body System.Tasking.Initialization is
76 package STPO renames System.Task_Primitives.Operations;
77 package SSL renames System.Soft_Links;
78 package AE renames Ada.Exceptions;
81 use Task_Primitives.Operations;
83 Global_Task_Lock : aliased System.Task_Primitives.RTS_Lock;
84 -- This is a global lock; it is used to execute in mutual exclusion
85 -- from all other tasks. It is only used by Task_Lock,
86 -- Task_Unlock, and Final_Task_Unlock.
88 function Current_Target_Exception return AE.Exception_Occurrence;
90 (Ada, Current_Target_Exception, "__gnat_current_target_exception");
91 -- Import this subprogram from the private part of Ada.Exceptions
93 ----------------------------------------------------------------------
94 -- Tasking versions of some services needed by non-tasking programs --
95 ----------------------------------------------------------------------
98 -- Locks out other tasks. Preceding a section of code by Task_Lock and
99 -- following it by Task_Unlock creates a critical region. This is used
100 -- for ensuring that a region of non-tasking code (such as code used to
101 -- allocate memory) is tasking safe. Note that it is valid for calls to
102 -- Task_Lock/Task_Unlock to be nested, and this must work properly, i.e.
103 -- only the corresponding outer level Task_Unlock will actually unlock.
105 procedure Task_Unlock;
106 -- Releases lock previously set by call to Task_Lock. In the nested case,
107 -- all nested locks must be released before other tasks competing for the
108 -- tasking lock are released.
110 function Get_Exc_Stack_Addr return Address;
111 -- Get the exception stack for the current task
113 procedure Set_Exc_Stack_Addr (Self_ID : Address; Addr : Address);
114 -- Self_ID is the Task_Id of the task that gets the exception stack.
115 -- For Self_ID = Null_Address, the current task gets the exception stack.
117 function Get_Stack_Info return Stack_Checking.Stack_Access;
118 -- Get access to the current task's Stack_Info
120 procedure Update_Exception
121 (X : AE.Exception_Occurrence := Current_Target_Exception);
122 -- Handle exception setting and check for pending actions
124 function Task_Name return String;
125 -- Returns current task's name
127 ------------------------
128 -- Local Subprograms --
129 ------------------------
131 ----------------------------
132 -- Tasking Initialization --
133 ----------------------------
135 procedure Gnat_Install_Locks (Lock, Unlock : SSL.No_Param_Proc);
136 pragma Import (C, Gnat_Install_Locks, "__gnatlib_install_locks");
137 -- Used by Init_RTS to install procedure Lock and Unlock for the
138 -- thread locking. This has no effect on GCC 2. For GCC 3,
139 -- it has an effect only if gcc is configured with
140 -- --enable_threads=gnat.
143 -- This procedure completes the initialization of the GNARL. The first
144 -- part of the initialization is done in the body of System.Tasking.
145 -- It consists of initializing global locks, and installing tasking
146 -- versions of certain operations used by the compiler. Init_RTS is called
147 -- during elaboration.
149 --------------------------
150 -- Change_Base_Priority --
151 --------------------------
153 -- Call only with abort deferred and holding Self_ID locked
155 procedure Change_Base_Priority (T : Task_Id) is
157 if T.Common.Base_Priority /= T.New_Base_Priority then
158 T.Common.Base_Priority := T.New_Base_Priority;
159 Set_Priority (T, T.Common.Base_Priority);
161 end Change_Base_Priority;
163 ------------------------
164 -- Check_Abort_Status --
165 ------------------------
167 function Check_Abort_Status return Integer is
168 Self_ID : constant Task_Id := Self;
170 if Self_ID /= null and then Self_ID.Deferral_Level = 0
171 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
177 end Check_Abort_Status;
183 procedure Defer_Abort (Self_ID : Task_Id) is
185 if No_Abort and then not Dynamic_Priority_Support then
189 pragma Assert (Self_ID.Deferral_Level = 0);
192 -- (Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level);
194 -- The above check has been useful in detecting mismatched defer/undefer
195 -- pairs. You may uncomment it when testing on systems that support
198 -- If the OS supports preemptive abort (e.g. pthread_kill), it should
199 -- have happened already. A problem is with systems that do not support
200 -- preemptive abort, and so rely on polling. On such systems we may get
201 -- false failures of the assertion, since polling for pending abort does
202 -- no occur until the abort undefer operation.
204 -- Even on systems that only poll for abort, the assertion may be useful
205 -- for catching missed abort completion polling points. The operations
206 -- that undefer abort poll for pending aborts. This covers most of the
207 -- places where the core Ada semantics require abort to be caught,
208 -- without any special attention. However, this generally happens on
209 -- exit from runtime system call, which means a pending abort will not
210 -- be noticed on the way into the runtime system. We considered adding a
211 -- check for pending aborts at this point, but chose not to, because of
212 -- the overhead. Instead, we searched for RTS calls where abort
213 -- completion is required and a task could go farther than Ada allows
214 -- before undeferring abort; we then modified the code to ensure the
215 -- abort would be detected.
217 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
220 --------------------------
221 -- Defer_Abort_Nestable --
222 --------------------------
224 procedure Defer_Abort_Nestable (Self_ID : Task_Id) is
226 if No_Abort and then not Dynamic_Priority_Support then
231 -- ((Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level or else
232 -- Self_ID.Deferral_Level > 0));
234 -- See comment in Defer_Abort on the situations in which it may be
235 -- useful to uncomment the above assertion.
237 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
238 end Defer_Abort_Nestable;
244 procedure Defer_Abortion is
248 if No_Abort and then not Dynamic_Priority_Support then
252 Self_ID := STPO.Self;
253 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
256 -----------------------
257 -- Do_Pending_Action --
258 -----------------------
260 -- Call only when holding no locks
262 procedure Do_Pending_Action (Self_ID : Task_Id) is
263 use type Ada.Exceptions.Exception_Id;
266 pragma Assert (Self_ID = Self and then Self_ID.Deferral_Level = 0);
268 -- Needs loop to recheck for pending action in case a new one occurred
269 -- while we had abort deferred below.
272 -- Temporarily defer abort so that we can lock Self_ID
274 Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
280 Write_Lock (Self_ID);
281 Self_ID.Pending_Action := False;
282 Poll_Base_Priority_Change (Self_ID);
289 -- Restore the original Deferral value
291 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1;
293 if not Self_ID.Pending_Action then
294 if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then
295 if not Self_ID.Aborting then
296 Self_ID.Aborting := True;
298 (Debug.Trace (Self_ID, "raise Abort_Signal", 'B'));
299 raise Standard'Abort_Signal;
301 pragma Assert (not Self_ID.ATC_Hack);
303 elsif Self_ID.ATC_Hack then
304 -- The solution really belongs in the Abort_Signal handler
305 -- for async. entry calls. The present hack is very
306 -- fragile. It relies that the very next point after
307 -- Exit_One_ATC_Level at which the task becomes abortable
308 -- will be the call to Undefer_Abort in the
309 -- Abort_Signal handler.
311 Self_ID.ATC_Hack := False;
315 (Self_ID, "raise Abort_Signal (ATC hack)", 'B'));
316 raise Standard'Abort_Signal;
323 end Do_Pending_Action;
325 -----------------------
326 -- Final_Task_Unlock --
327 -----------------------
329 -- This version is only for use in Terminate_Task, when the task
330 -- is relinquishing further rights to its own ATCB.
331 -- There is a very interesting potential race condition there, where
332 -- the old task may run concurrently with a new task that is allocated
333 -- the old tasks (now reused) ATCB. The critical thing here is to
334 -- not make any reference to the ATCB after the lock is released.
335 -- See also comments on Terminate_Task and Unlock.
337 procedure Final_Task_Unlock (Self_ID : Task_Id) is
339 pragma Assert (Self_ID.Global_Task_Lock_Nesting = 1);
340 Unlock (Global_Task_Lock'Access, Global_Lock => True);
341 end Final_Task_Unlock;
347 procedure Init_RTS is
351 -- Terminate run time (regular vs restricted) specific initialization
352 -- of the environment task.
354 Self_Id := Environment_Task;
355 Self_Id.Master_of_Task := Environment_Task_Level;
356 Self_Id.Master_Within := Self_Id.Master_of_Task + 1;
358 for L in Self_Id.Entry_Calls'Range loop
359 Self_Id.Entry_Calls (L).Self := Self_Id;
360 Self_Id.Entry_Calls (L).Level := L;
363 Self_Id.Awake_Count := 1;
364 Self_Id.Alive_Count := 1;
366 Self_Id.Master_Within := Library_Task_Level;
367 -- Normally, a task starts out with internal master nesting level
368 -- one larger than external master nesting level. It is incremented
369 -- to one by Enter_Master, which is called in the task body only if
370 -- the compiler thinks the task may have dependent tasks. There is no
371 -- corresponding call to Enter_Master for the environment task, so we
372 -- would need to increment it to 2 here. Instead, we set it to 3.
373 -- By doing this we reserve the level 2 for server tasks of the runtime
374 -- system. The environment task does not need to wait for these server
376 -- Initialize lock used to implement mutual exclusion between all tasks
378 Initialize_Lock (Global_Task_Lock'Access, STPO.Global_Task_Level);
380 -- Notify that the tasking run time has been elaborated so that
381 -- the tasking version of the soft links can be used.
383 if not No_Abort or else Dynamic_Priority_Support then
384 SSL.Abort_Defer := Defer_Abortion'Access;
385 SSL.Abort_Undefer := Undefer_Abortion'Access;
388 SSL.Update_Exception := Update_Exception'Access;
389 SSL.Lock_Task := Task_Lock'Access;
390 SSL.Unlock_Task := Task_Unlock'Access;
391 SSL.Get_Exc_Stack_Addr := Get_Exc_Stack_Addr'Access;
392 SSL.Set_Exc_Stack_Addr := Set_Exc_Stack_Addr'Access;
393 SSL.Check_Abort_Status := Check_Abort_Status'Access;
394 SSL.Get_Stack_Info := Get_Stack_Info'Access;
395 SSL.Task_Name := Task_Name'Access;
397 SSL.Set_Exc_Stack_Addr (Null_Address, SSL.Get_Exc_Stack_Addr_NT);
399 -- Initialize the tasking soft links (if not done yet) that are common
400 -- to the full and the restricted run times.
402 SSL.Tasking.Init_Tasking_Soft_Links;
404 -- Install tasking locks in the GCC runtime
406 Gnat_Install_Locks (Task_Lock'Access, Task_Unlock'Access);
408 -- Abort is deferred in a new ATCB, so we need to undefer abort
409 -- at this stage to make the environment task abortable.
411 Undefer_Abort (Environment_Task);
414 ---------------------------
415 -- Locked_Abort_To_Level--
416 ---------------------------
418 -- Abort a task to the specified ATC nesting level.
419 -- Call this only with T locked.
421 -- An earlier version of this code contained a call to Wakeup. That
422 -- should not be necessary here, if Abort_Task is implemented correctly,
423 -- since Abort_Task should include the effect of Wakeup. However, the
424 -- above call was in earlier versions of this file, and at least for
425 -- some targets Abort_Task has not beek doing Wakeup. It should not
426 -- hurt to uncomment the above call, until the error is corrected for
429 -- See extended comments in package body System.Tasking.Abort for the
430 -- overall design of the implementation of task abort.
431 -- ??? there is no such package ???
433 -- If the task is sleeping it will be in an abort-deferred region, and
434 -- will not have Abort_Signal raised by Abort_Task. Such an "abort
435 -- deferral" is just to protect the RTS internals, and not necessarily
436 -- required to enforce Ada semantics. Abort_Task should wake the task up
437 -- and let it decide if it wants to complete the aborted construct
440 -- Note that the effect of the lowl-level Abort_Task is not persistent.
441 -- If the target task is not blocked, this wakeup will be missed.
443 -- We don't bother calling Abort_Task if this task is aborting itself,
444 -- since we are inside the RTS and have abort deferred. Similarly, We
445 -- don't bother to call Abort_Task if T is terminated, since there is
446 -- no need to abort a terminated task, and it could be dangerous to try
447 -- if the task has stopped executing.
449 -- Note that an earlier version of this code had some false reasoning
450 -- about being able to reliably wake up a task that had suspended on
451 -- a blocking system call that does not atomically relase the task's
452 -- lock (e.g., UNIX nanosleep, which we once thought could be used to
453 -- implement delays). That still left the possibility of missed
456 -- We cannot safely call Vulnerable_Complete_Activation here, since that
457 -- requires locking Self_ID.Parent. The anti-deadlock lock ordering rules
458 -- would then require us to release the lock on Self_ID first, which would
459 -- create a timing window for other tasks to lock Self_ID. This is
460 -- significant for tasks that may be aborted before their execution can
461 -- enter the task body, and so they do not get a chance to call
462 -- Complete_Task. The actual work for this case is done in Terminate_Task.
464 procedure Locked_Abort_To_Level
470 if not T.Aborting and then T /= Self_ID then
471 case T.Common.State is
472 when Unactivated | Terminated =>
473 pragma Assert (False);
477 -- This is needed to cancel an asynchronous protected entry
478 -- call during a requeue with abort.
481 (T.ATC_Nesting_Level).Cancellation_Attempted := True;
483 when Interrupt_Server_Blocked_On_Event_Flag =>
488 Interrupt_Server_Idle_Sleep |
489 Interrupt_Server_Blocked_Interrupt_Sleep |
492 Wakeup (T, T.Common.State);
494 when Acceptor_Sleep =>
495 T.Open_Accepts := null;
496 Wakeup (T, T.Common.State);
498 when Entry_Caller_Sleep =>
500 (T.ATC_Nesting_Level).Cancellation_Attempted := True;
501 Wakeup (T, T.Common.State);
503 when Activator_Sleep |
504 Master_Completion_Sleep |
505 Master_Phase_2_Sleep |
511 if T.Pending_ATC_Level > L then
512 T.Pending_ATC_Level := L;
513 T.Pending_Action := True;
519 -- This prevents aborted task from accepting calls
523 -- The test above is just a heuristic, to reduce wasteful
524 -- calls to Abort_Task. We are holding T locked, and this
525 -- value will not be set to False except with T also locked,
526 -- inside Exit_One_ATC_Level, so we should not miss wakeups.
528 if T.Common.State = Acceptor_Sleep then
529 T.Open_Accepts := null;
532 elsif T /= Self_ID and then
533 (T.Common.State = Runnable
534 or else T.Common.State = Interrupt_Server_Blocked_On_Event_Flag)
535 -- The task is blocked on a system call waiting for the
536 -- completion event. In this case Abort_Task may need to take
537 -- special action in order to succeed. Example system: VMS.
543 end Locked_Abort_To_Level;
545 -------------------------------
546 -- Poll_Base_Priority_Change --
547 -------------------------------
549 -- Poll for pending base priority change and for held tasks.
550 -- This should always be called with (only) Self_ID locked.
551 -- It may temporarily release Self_ID's lock.
553 -- The call to Yield is to force enqueuing at the
554 -- tail of the dispatching queue.
556 -- We must unlock Self_ID for this to take effect,
557 -- since we are inheriting high active priority from the lock.
559 -- See also Poll_Base_Priority_Change_At_Entry_Call,
560 -- in package System.Tasking.Entry_Calls.
562 -- In this version, we check if the task is held too because
563 -- doing this only in Do_Pending_Action is not enough.
565 procedure Poll_Base_Priority_Change (Self_ID : Task_Id) is
567 if Dynamic_Priority_Support and then Self_ID.Pending_Priority_Change then
569 -- Check for ceiling violations ???
571 Self_ID.Pending_Priority_Change := False;
573 if Self_ID.Common.Base_Priority = Self_ID.New_Base_Priority then
581 Write_Lock (Self_ID);
584 elsif Self_ID.Common.Base_Priority < Self_ID.New_Base_Priority then
585 Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
586 Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
591 Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
592 Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
601 Write_Lock (Self_ID);
605 end Poll_Base_Priority_Change;
607 --------------------------------
608 -- Remove_From_All_Tasks_List --
609 --------------------------------
611 procedure Remove_From_All_Tasks_List (T : Task_Id) is
617 (Debug.Trace (Self, "Remove_From_All_Tasks_List", 'C'));
619 Previous := Null_Task;
622 while C /= Null_Task loop
624 if Previous = Null_Task then
626 All_Tasks_List.Common.All_Tasks_Link;
628 Previous.Common.All_Tasks_Link := C.Common.All_Tasks_Link;
635 C := C.Common.All_Tasks_Link;
638 pragma Assert (False);
639 end Remove_From_All_Tasks_List;
645 procedure Task_Lock (Self_ID : Task_Id) is
647 Self_ID.Global_Task_Lock_Nesting := Self_ID.Global_Task_Lock_Nesting + 1;
649 if Self_ID.Global_Task_Lock_Nesting = 1 then
650 Defer_Abort_Nestable (Self_ID);
651 Write_Lock (Global_Task_Lock'Access, Global_Lock => True);
655 procedure Task_Lock is
657 Task_Lock (STPO.Self);
664 function Task_Name return String is
665 Self_Id : constant Task_Id := STPO.Self;
668 return Self_Id.Common.Task_Image (1 .. Self_Id.Common.Task_Image_Len);
675 procedure Task_Unlock (Self_ID : Task_Id) is
677 pragma Assert (Self_ID.Global_Task_Lock_Nesting > 0);
678 Self_ID.Global_Task_Lock_Nesting := Self_ID.Global_Task_Lock_Nesting - 1;
680 if Self_ID.Global_Task_Lock_Nesting = 0 then
681 Unlock (Global_Task_Lock'Access, Global_Lock => True);
682 Undefer_Abort_Nestable (Self_ID);
686 procedure Task_Unlock is
688 Task_Unlock (STPO.Self);
695 -- Precondition : Self does not hold any locks!
697 -- Undefer_Abort is called on any abort completion point (aka.
698 -- synchronization point). It performs the following actions if they
699 -- are pending: (1) change the base priority, (2) abort the task.
701 -- The priority change has to occur before abort. Otherwise, it would
702 -- take effect no earlier than the next abort completion point.
704 procedure Undefer_Abort (Self_ID : Task_Id) is
706 if No_Abort and then not Dynamic_Priority_Support then
710 pragma Assert (Self_ID.Deferral_Level = 1);
712 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1;
714 if Self_ID.Deferral_Level = 0 then
715 pragma Assert (Check_No_Locks (Self_ID));
717 if Self_ID.Pending_Action then
718 Do_Pending_Action (Self_ID);
723 ----------------------------
724 -- Undefer_Abort_Nestable --
725 ----------------------------
727 -- An earlier version would re-defer abort if an abort is in progress.
728 -- Then, we modified the effect of the raise statement so that it defers
729 -- abort until control reaches a handler. That was done to prevent
730 -- "skipping over" a handler if another asynchronous abort occurs during
731 -- the propagation of the abort to the handler.
733 -- There has been talk of reversing that decision, based on a newer
734 -- implementation of exception propagation. Care must be taken to evaluate
735 -- how such a change would interact with the above code and all the places
736 -- where abort-deferral is used to bridge over critical transitions, such
737 -- as entry to the scope of a region with a finalizer and entry into the
738 -- body of an accept-procedure.
740 procedure Undefer_Abort_Nestable (Self_ID : Task_Id) is
742 if No_Abort and then not Dynamic_Priority_Support then
746 pragma Assert (Self_ID.Deferral_Level > 0);
748 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1;
750 if Self_ID.Deferral_Level = 0 then
752 pragma Assert (Check_No_Locks (Self_ID));
754 if Self_ID.Pending_Action then
755 Do_Pending_Action (Self_ID);
758 end Undefer_Abort_Nestable;
760 ----------------------
761 -- Undefer_Abortion --
762 ----------------------
764 -- Phase out RTS-internal use of Undefer_Abortion to reduce overhead due
765 -- to multiple calls to Self.
767 procedure Undefer_Abortion is
771 if No_Abort and then not Dynamic_Priority_Support then
775 Self_ID := STPO.Self;
777 if Self_ID.Deferral_Level = 0 then
779 -- In case there are different views on whether Abort is supported
780 -- between the expander and the run time, we may end up with
781 -- Self_ID.Deferral_Level being equal to zero, when called from
782 -- the procedure created by the expander that corresponds to a
785 -- In this case, there's nothing to be done
787 -- See related code in System.Tasking.Stages.Create_Task resetting
788 -- Deferral_Level when System.Restrictions.Abort_Allowed is False.
793 pragma Assert (Self_ID.Deferral_Level > 0);
794 Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1;
796 if Self_ID.Deferral_Level = 0 then
797 pragma Assert (Check_No_Locks (Self_ID));
799 if Self_ID.Pending_Action then
800 Do_Pending_Action (Self_ID);
803 end Undefer_Abortion;
805 ----------------------
806 -- Update_Exception --
807 ----------------------
809 -- Call only when holding no locks
811 procedure Update_Exception
812 (X : AE.Exception_Occurrence := Current_Target_Exception)
814 Self_Id : constant Task_Id := Self;
818 Save_Occurrence (Self_Id.Common.Compiler_Data.Current_Excep, X);
820 if Self_Id.Deferral_Level = 0 then
821 if Self_Id.Pending_Action then
822 Self_Id.Pending_Action := False;
823 Self_Id.Deferral_Level := Self_Id.Deferral_Level + 1;
829 Write_Lock (Self_Id);
830 Self_Id.Pending_Action := False;
831 Poll_Base_Priority_Change (Self_Id);
838 Self_Id.Deferral_Level := Self_Id.Deferral_Level - 1;
840 if Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level then
841 if not Self_Id.Aborting then
842 Self_Id.Aborting := True;
843 raise Standard'Abort_Signal;
848 end Update_Exception;
850 --------------------------
851 -- Wakeup_Entry_Caller --
852 --------------------------
854 -- This is called at the end of service of an entry call, to abort the
855 -- caller if he is in an abortable part, and to wake up the caller if it
856 -- is on Entry_Caller_Sleep. It assumes that the call is already off-queue.
858 -- (This enforces the rule that a task must be off-queue if its state is
859 -- Done or Cancelled.) Call it holding the lock of Entry_Call.Self.
861 -- Timed_Call or Simple_Call:
862 -- The caller is waiting on Entry_Caller_Sleep, in
863 -- Wait_For_Completion, or Wait_For_Completion_With_Timeout.
866 -- The caller might be in Wait_For_Completion,
867 -- waiting for a rendezvous (possibly requeued without abort)
870 -- Asynchronous_Call:
871 -- The caller may be executing in the abortable part o
872 -- an async. select, or on a time delay,
873 -- if Entry_Call.State >= Was_Abortable.
875 procedure Wakeup_Entry_Caller
877 Entry_Call : Entry_Call_Link;
878 New_State : Entry_Call_State)
880 Caller : constant Task_Id := Entry_Call.Self;
883 pragma Debug (Debug.Trace
884 (Self_ID, "Wakeup_Entry_Caller", 'E', Caller));
885 pragma Assert (New_State = Done or else New_State = Cancelled);
888 (Caller.Common.State /= Terminated
889 and then Caller.Common.State /= Unactivated);
891 Entry_Call.State := New_State;
893 if Entry_Call.Mode = Asynchronous_Call then
895 -- Abort the caller in his abortable part,
896 -- but do so only if call has been queued abortably
898 if Entry_Call.State >= Was_Abortable or else New_State = Done then
899 Locked_Abort_To_Level (Self_ID, Caller, Entry_Call.Level - 1);
902 elsif Caller.Common.State = Entry_Caller_Sleep then
903 Wakeup (Caller, Entry_Caller_Sleep);
905 end Wakeup_Entry_Caller;
907 ----------------------
908 -- Soft-Link Bodies --
909 ----------------------
911 function Get_Exc_Stack_Addr return Address is
913 return STPO.Self.Common.Compiler_Data.Exc_Stack_Addr;
914 end Get_Exc_Stack_Addr;
916 function Get_Stack_Info return Stack_Checking.Stack_Access is
918 return STPO.Self.Common.Compiler_Data.Pri_Stack_Info'Access;
921 procedure Set_Exc_Stack_Addr (Self_ID : Address; Addr : Address) is
922 Me : Task_Id := To_Task_Id (Self_ID);
924 if Me = Null_Task then
928 Me.Common.Compiler_Data.Exc_Stack_Addr := Addr;
929 end Set_Exc_Stack_Addr;
931 -----------------------
932 -- Soft-Link Dummies --
933 -----------------------
935 -- These are dummies for subprograms that are only needed by certain
936 -- optional run-time system packages. If they are needed, the soft
937 -- links will be redirected to the real subprogram by elaboration of
938 -- the subprogram body where the real subprogram is declared.
940 procedure Finalize_Attributes (T : Task_Id) is
941 pragma Warnings (Off, T);
945 end Finalize_Attributes;
947 procedure Initialize_Attributes (T : Task_Id) is
948 pragma Warnings (Off, T);
952 end Initialize_Attributes;
956 end System.Tasking.Initialization;