1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- S Y S T E M . T A S K _ P R I M I T I V E S . O P E R A T I O N S --
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, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, 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 -- This is an OS/2 version of this package
36 -- This package contains all the GNULL primitives that interface directly
37 -- with the underlying OS.
40 -- Turn off polling, we do not want ATC polling to take place during
41 -- tasking operations. It causes infinite loops and other problems.
43 with System.Tasking.Debug;
44 -- used for Known_Tasks
46 with System.OS_Primitives;
47 -- used for Delay_Modes
50 with Interfaces.OS2Lib.Errors;
51 with Interfaces.OS2Lib.Threads;
52 with Interfaces.OS2Lib.Synchronization;
57 with Interfaces.C.Strings;
60 with System.Parameters;
63 with Unchecked_Conversion;
64 with Unchecked_Deallocation;
66 package body System.Task_Primitives.Operations is
68 package IC renames Interfaces.C;
69 package ICS renames Interfaces.C.Strings;
70 package OSP renames System.OS_Primitives;
72 use Interfaces.OS2Lib;
73 use Interfaces.OS2Lib.Errors;
74 use Interfaces.OS2Lib.Threads;
75 use Interfaces.OS2Lib.Synchronization;
76 use System.Parameters;
77 use System.Tasking.Debug;
79 use System.OS_Interface;
81 use System.OS_Primitives;
87 Max_Locks_Per_Task : constant := 100;
88 Suppress_Owner_Check : constant Boolean := False;
94 subtype Lock_Range is Integer range 0 .. Max_Locks_Per_Task;
100 -- The OS/2 DosAllocThreadLocalMemory API is used to allocate our TCB_Ptr
102 -- This API reserves a small range of virtual addresses that is backed
103 -- by different physical memory for each running thread. In this case we
104 -- create a pointer at a fixed address that points to the TCB_Ptr for the
105 -- running thread. So all threads will be able to query and update their
106 -- own TCB_Ptr without destroying the TCB_Ptr of other threads.
108 type Thread_Local_Data is record
109 Self_ID : Task_Id; -- ID of the current thread
110 Lock_Prio_Level : Lock_Range; -- Nr of priority changes due to locks
112 -- ... room for expansion here, if we decide to make access to
113 -- jump-buffer and exception stack more efficient in future
116 type Access_Thread_Local_Data is access all Thread_Local_Data;
118 -- Pointer to Thread Local Data
119 Thread_Local_Data_Ptr : aliased Access_Thread_Local_Data;
121 type PPTLD is access all Access_Thread_Local_Data;
123 Single_RTS_Lock : aliased RTS_Lock;
124 -- This is a lock to allow only one thread of control in the RTS at
125 -- a time; it is used to execute in mutual exclusion from all other tasks.
126 -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List
128 Environment_Task_Id : Task_Id;
129 -- A variable to hold Task_Id for the environment task
131 -----------------------
132 -- Local Subprograms --
133 -----------------------
135 function To_PPVOID is new Unchecked_Conversion (PPTLD, PPVOID);
136 function To_Address is new Unchecked_Conversion (Task_Id, System.Address);
137 function To_PFNTHREAD is
138 new Unchecked_Conversion (System.Address, PFNTHREAD);
140 function To_MS (D : Duration) return ULONG;
142 procedure Set_Temporary_Priority
144 New_Priority : in System.Any_Priority);
150 function To_MS (D : Duration) return ULONG is
152 return ULONG (D * 1_000);
159 function Monotonic_Clock return Duration renames OSP.Monotonic_Clock;
165 function RT_Resolution return Duration is
174 -- OS/2 only has limited support for asynchronous signals.
175 -- It seems not to be possible to jump out of an exception
176 -- handler or to change the execution context of the thread.
177 -- So asynchonous transfer of control is not supported.
183 -- The underlying thread system sets a guard page at the
184 -- bottom of a thread stack, so nothing is needed.
185 -- ??? Check the comment above
187 procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
188 pragma Unreferenced (T);
189 pragma Unreferenced (On);
198 function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
200 return OSI.Thread_Id (T.Common.LL.Thread);
207 function Self return Task_Id is
208 Self_ID : Task_Id renames Thread_Local_Data_Ptr.Self_ID;
211 -- Check that the thread local data has been initialized
214 ((Thread_Local_Data_Ptr /= null
215 and then Thread_Local_Data_Ptr.Self_ID /= null));
220 ---------------------
221 -- Initialize_Lock --
222 ---------------------
224 procedure Initialize_Lock
225 (Prio : System.Any_Priority;
230 (ICS.Null_Ptr, L.Mutex'Unchecked_Access, 0, False32) /= NO_ERROR
235 pragma Assert (L.Mutex /= 0, "Error creating Mutex");
237 L.Owner_ID := Null_Address;
240 procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
241 pragma Unreferenced (Level);
245 (ICS.Null_Ptr, L.Mutex'Unchecked_Access, 0, False32) /= NO_ERROR
250 pragma Assert (L.Mutex /= 0, "Error creating Mutex");
252 L.Priority := System.Any_Priority'Last;
253 L.Owner_ID := Null_Address;
260 procedure Finalize_Lock (L : access Lock) is
262 Must_Not_Fail (DosCloseMutexSem (L.Mutex));
265 procedure Finalize_Lock (L : access RTS_Lock) is
267 Must_Not_Fail (DosCloseMutexSem (L.Mutex));
274 procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
275 Self_ID : constant Task_Id := Thread_Local_Data_Ptr.Self_ID;
276 Old_Priority : constant Any_Priority :=
277 Self_ID.Common.LL.Current_Priority;
280 if L.Priority < Old_Priority then
281 Ceiling_Violation := True;
285 Ceiling_Violation := False;
287 -- Increase priority before getting the lock
288 -- to prevent priority inversion
290 Thread_Local_Data_Ptr.Lock_Prio_Level :=
291 Thread_Local_Data_Ptr.Lock_Prio_Level + 1;
292 if L.Priority > Old_Priority then
293 Set_Temporary_Priority (Self_ID, L.Priority);
296 -- Request the lock and then update the lock owner data
298 Must_Not_Fail (DosRequestMutexSem (L.Mutex, SEM_INDEFINITE_WAIT));
299 L.Owner_Priority := Old_Priority;
300 L.Owner_ID := Self_ID.all'Address;
304 (L : access RTS_Lock;
305 Global_Lock : Boolean := False)
308 Old_Priority : Any_Priority;
311 if not Single_Lock or else Global_Lock then
312 Self_ID := Thread_Local_Data_Ptr.Self_ID;
313 Old_Priority := Self_ID.Common.LL.Current_Priority;
315 -- Increase priority before getting the lock
316 -- to prevent priority inversion
318 Thread_Local_Data_Ptr.Lock_Prio_Level :=
319 Thread_Local_Data_Ptr.Lock_Prio_Level + 1;
321 if L.Priority > Old_Priority then
322 Set_Temporary_Priority (Self_ID, L.Priority);
325 -- Request the lock and then update the lock owner data
327 Must_Not_Fail (DosRequestMutexSem (L.Mutex, SEM_INDEFINITE_WAIT));
328 L.Owner_Priority := Old_Priority;
329 L.Owner_ID := Self_ID.all'Address;
333 procedure Write_Lock (T : Task_Id) is
335 if not Single_Lock then
337 -- Request the lock and then update the lock owner data
340 (DosRequestMutexSem (T.Common.LL.L.Mutex, SEM_INDEFINITE_WAIT));
341 T.Common.LL.L.Owner_ID := Null_Address;
350 (L : access Lock; Ceiling_Violation : out Boolean) renames Write_Lock;
356 procedure Unlock (L : access Lock) is
357 Self_ID : constant Task_Id := Thread_Local_Data_Ptr.Self_ID;
358 Old_Priority : constant Any_Priority := L.Owner_Priority;
361 -- Check that this task holds the lock
363 pragma Assert (Suppress_Owner_Check
364 or else L.Owner_ID = Self_ID.all'Address);
366 -- Upate the owner data
368 L.Owner_ID := Null_Address;
370 -- Do the actual unlocking. No more references
371 -- to owner data of L after this point.
373 Must_Not_Fail (DosReleaseMutexSem (L.Mutex));
375 -- Reset priority after unlocking to avoid priority inversion
377 Thread_Local_Data_Ptr.Lock_Prio_Level :=
378 Thread_Local_Data_Ptr.Lock_Prio_Level - 1;
379 if L.Priority /= Old_Priority then
380 Set_Temporary_Priority (Self_ID, Old_Priority);
384 procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
386 Old_Priority : Any_Priority;
389 if not Single_Lock or else Global_Lock then
390 Self_ID := Thread_Local_Data_Ptr.Self_ID;
391 Old_Priority := L.Owner_Priority;
392 -- Check that this task holds the lock
394 pragma Assert (Suppress_Owner_Check
395 or else L.Owner_ID = Self_ID.all'Address);
397 -- Upate the owner data
399 L.Owner_ID := Null_Address;
401 -- Do the actual unlocking. No more references
402 -- to owner data of L after this point.
404 Must_Not_Fail (DosReleaseMutexSem (L.Mutex));
406 -- Reset priority after unlocking to avoid priority inversion
408 Thread_Local_Data_Ptr.Lock_Prio_Level :=
409 Thread_Local_Data_Ptr.Lock_Prio_Level - 1;
411 if L.Priority /= Old_Priority then
412 Set_Temporary_Priority (Self_ID, Old_Priority);
417 procedure Unlock (T : Task_Id) is
419 if not Single_Lock then
421 -- Check the owner data
423 pragma Assert (Suppress_Owner_Check
424 or else T.Common.LL.L.Owner_ID = Null_Address);
426 -- Do the actual unlocking. No more references
427 -- to owner data of T.Common.LL.L after this point.
429 Must_Not_Fail (DosReleaseMutexSem (T.Common.LL.L.Mutex));
439 Reason : System.Tasking.Task_States)
441 pragma Unreferenced (Reason);
443 Count : aliased ULONG; -- Used to store dummy result
446 -- Must reset Cond BEFORE L is unlocked
449 (DosResetEventSem (Self_ID.Common.LL.CV, Count'Unchecked_Access));
457 -- No problem if we are interrupted here.
458 -- If the condition is signaled, DosWaitEventSem will simply not block.
461 (DosWaitEventSem (Self_ID.Common.LL.CV, SEM_INDEFINITE_WAIT));
463 -- Since L was previously accquired, lock operation should not fail
468 Write_Lock (Self_ID);
476 -- This is for use within the run-time system, so abort is
477 -- assumed to be already deferred, and the caller should be
478 -- holding its own ATCB lock.
480 -- Pre-assertion: Cond is posted
483 -- Post-assertion: Cond is posted
486 procedure Timed_Sleep
489 Mode : ST.Delay_Modes;
490 Reason : System.Tasking.Task_States;
491 Timedout : out Boolean;
492 Yielded : out Boolean)
494 pragma Unreferenced (Reason);
496 Check_Time : constant Duration := OSP.Monotonic_Clock;
501 Count : aliased ULONG; -- Used to store dummy result
504 -- Must reset Cond BEFORE Self_ID is unlocked
507 (DosResetEventSem (Self_ID.Common.LL.CV,
508 Count'Unchecked_Access));
519 if Mode = Relative then
521 Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
523 Rel_Time := Time - Check_Time;
527 if Rel_Time > 0.0 then
529 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
530 or else Self_ID.Pending_Priority_Change;
532 Time_Out := To_MS (Rel_Time);
533 Result := DosWaitEventSem (Self_ID.Common.LL.CV, Time_Out);
535 ((Result = NO_ERROR or Result = ERROR_TIMEOUT
536 or Result = ERROR_INTERRUPT));
539 -- What to do with error condition ERROR_NOT_ENOUGH_MEMORY? Can
540 -- we raise an exception here? And what about ERROR_INTERRUPT?
541 -- Should that be treated as a simple timeout?
542 -- For now, consider only ERROR_TIMEOUT to be a timeout.
544 exit when Abs_Time <= OSP.Monotonic_Clock;
546 if Result /= ERROR_TIMEOUT then
547 -- somebody may have called Wakeup for us
552 Rel_Time := Abs_Time - OSP.Monotonic_Clock;
556 -- Ensure post-condition
561 Write_Lock (Self_ID);
565 Sem_Must_Not_Fail (DosPostEventSem (Self_ID.Common.LL.CV));
573 procedure Timed_Delay
576 Mode : ST.Delay_Modes)
578 Check_Time : constant Duration := OSP.Monotonic_Clock;
581 Timedout : Boolean := True;
584 Count : aliased ULONG; -- Used to store dummy result
590 Write_Lock (Self_ID);
593 -- Must reset Cond BEFORE Self_ID is unlocked
596 (DosResetEventSem (Self_ID.Common.LL.CV,
597 Count'Unchecked_Access));
605 if Mode = Relative then
607 Abs_Time := Time + Check_Time;
609 Rel_Time := Time - Check_Time;
613 if Rel_Time > 0.0 then
614 Self_ID.Common.State := Delay_Sleep;
617 if Self_ID.Pending_Priority_Change then
618 Self_ID.Pending_Priority_Change := False;
619 Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
620 Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
623 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
625 Time_Out := To_MS (Rel_Time);
626 Result := DosWaitEventSem (Self_ID.Common.LL.CV, Time_Out);
628 exit when Abs_Time <= OSP.Monotonic_Clock;
630 Rel_Time := Abs_Time - OSP.Monotonic_Clock;
633 Self_ID.Common.State := Runnable;
634 Timedout := Result = ERROR_TIMEOUT;
640 Write_Lock (Self_ID);
644 Sem_Must_Not_Fail (DosPostEventSem (Self_ID.Common.LL.CV));
653 System.OS_Interface.Yield;
660 procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
661 pragma Unreferenced (Reason);
663 Sem_Must_Not_Fail (DosPostEventSem (T.Common.LL.CV));
670 procedure Yield (Do_Yield : Boolean := True) is
673 System.OS_Interface.Yield;
677 ----------------------------
678 -- Set_Temporary_Priority --
679 ----------------------------
681 procedure Set_Temporary_Priority
683 New_Priority : System.Any_Priority)
686 Delta_Priority : Integer;
689 -- When Lock_Prio_Level = 0, we always need to set the
690 -- Active_Priority. In this way we can make priority changes
691 -- due to locking independent of those caused by calling
694 if Thread_Local_Data_Ptr.Lock_Prio_Level = 0
695 or else New_Priority < T.Common.Current_Priority
697 Delta_Priority := T.Common.Current_Priority -
698 T.Common.LL.Current_Priority;
700 Delta_Priority := New_Priority - T.Common.LL.Current_Priority;
703 if Delta_Priority /= 0 then
704 -- ??? There is a race-condition here
705 -- The TCB is updated before the system call to make
706 -- pre-emption in the critical section less likely.
708 T.Common.LL.Current_Priority :=
709 T.Common.LL.Current_Priority + Delta_Priority;
711 (DosSetPriority (Scope => PRTYS_THREAD,
712 Class => PRTYC_NOCHANGE,
713 Delta_P => IC.long (Delta_Priority),
714 PorTid => T.Common.LL.Thread));
716 end Set_Temporary_Priority;
722 procedure Set_Priority
724 Prio : System.Any_Priority;
725 Loss_Of_Inheritance : Boolean := False)
727 pragma Unreferenced (Loss_Of_Inheritance);
729 T.Common.Current_Priority := Prio;
730 Set_Temporary_Priority (T, Prio);
737 function Get_Priority (T : Task_Id) return System.Any_Priority is
739 return T.Common.Current_Priority;
746 procedure Enter_Task (Self_ID : Task_Id) is
748 -- Initialize thread local data. Must be done first
750 Thread_Local_Data_Ptr.Self_ID := Self_ID;
751 Thread_Local_Data_Ptr.Lock_Prio_Level := 0;
755 for J in Known_Tasks'Range loop
756 if Known_Tasks (J) = null then
757 Known_Tasks (J) := Self_ID;
758 Self_ID.Known_Tasks_Index := J;
765 -- For OS/2, we can set Self_ID.Common.LL.Thread in
766 -- Create_Task, since the thread is created suspended.
767 -- That is, there is no danger of the thread racing ahead
768 -- and trying to reference Self_ID.Common.LL.Thread before it
769 -- has been initialized.
771 -- .... Do we need to do anything with signals for OS/2 ???
778 function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is
780 return new Ada_Task_Control_Block (Entry_Num);
787 function Is_Valid_Task return Boolean is
792 -----------------------------
793 -- Register_Foreign_Thread --
794 -----------------------------
796 function Register_Foreign_Thread return Task_Id is
799 end Register_Foreign_Thread;
805 procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
807 if DosCreateEventSem (ICS.Null_Ptr,
808 Self_ID.Common.LL.CV'Unchecked_Access, 0, True32) = NO_ERROR
811 and then DosCreateMutexSem
813 Self_ID.Common.LL.L.Mutex'Unchecked_Access,
818 Must_Not_Fail (DosCloseEventSem (Self_ID.Common.LL.CV));
823 -- We now want to do the equivalent of:
826 -- (Self_ID.Common.LL.L'Unchecked_Access, ATCB_Level);
828 -- But we avoid that because the Initialize_TCB routine has an
829 -- exception handler, and it is too early for us to deal with
830 -- installing handlers (see comment below), so we do our own
831 -- Initialize_Lock operation manually.
833 Self_ID.Common.LL.L.Priority := System.Any_Priority'Last;
834 Self_ID.Common.LL.L.Owner_ID := Null_Address;
840 -- Note: at one time we had an exception handler here, whose code
845 -- Assumes any failure must be due to insufficient resources
847 -- when Storage_Error =>
848 -- Must_Not_Fail (DosCloseEventSem (Self_ID.Common.LL.CV));
849 -- Succeeded := False;
851 -- but that won't work with the old exception scheme, since it would
852 -- result in messing with Jmpbuf values too early. If and when we get
853 -- switched entirely to the new zero-cost exception scheme, we could
854 -- put this handler back in!
861 procedure Create_Task
863 Wrapper : System.Address;
864 Stack_Size : System.Parameters.Size_Type;
865 Priority : System.Any_Priority;
866 Succeeded : out Boolean)
868 Result : aliased APIRET;
869 Adjusted_Stack_Size : System.Parameters.Size_Type;
870 use System.Parameters;
873 -- In OS/2 the allocated stack size should be based on the
874 -- amount of address space that should be reserved for the stack.
875 -- Actual memory will only be used when the stack is touched anyway.
877 -- The new minimum size is 12 kB, although the EMX docs
878 -- recommend a minimum size of 32 kB. (The original was 4 kB)
879 -- Systems that use many tasks (say > 30) and require much
880 -- memory may run out of virtual address space, since OS/2
881 -- has a per-proces limit of 512 MB, of which max. 300 MB is
882 -- usable in practise.
884 if Stack_Size = Unspecified_Size then
885 Adjusted_Stack_Size := Default_Stack_Size;
887 elsif Stack_Size < Minimum_Stack_Size then
888 Adjusted_Stack_Size := Minimum_Stack_Size;
891 Adjusted_Stack_Size := Stack_Size;
895 -- Because DosCreateThread is called directly here, the
896 -- C RTL doesn't get initialized for the new thead. EMX by
897 -- default uses per-thread local heaps in addition to the
898 -- global heap. There might be other effects of by-passing the
901 -- When using _beginthread the newly created thread is not
902 -- blocked initially. Does this matter or can I create the
903 -- thread running anyway? The LL.Thread variable will be set
904 -- anyway because the variable is passed by reference to OS/2.
906 T.Common.LL.Wrapper := To_PFNTHREAD (Wrapper);
908 -- The OS implicitly gives the new task the priority of this task
910 T.Common.LL.Current_Priority := Self.Common.LL.Current_Priority;
912 -- If task was locked before activator task was
913 -- initialized, assume it has OS standard priority
915 if T.Common.LL.L.Owner_Priority not in Any_Priority'Range then
916 T.Common.LL.L.Owner_Priority := 1;
919 -- Create the thread, in blocked mode
921 Result := DosCreateThread
922 (F_ptid => T.Common.LL.Thread'Unchecked_Access,
923 pfn => T.Common.LL.Wrapper,
924 param => To_Address (T),
925 flag => Block_Child + Commit_Stack,
926 cbStack => ULONG (Adjusted_Stack_Size));
928 Succeeded := (Result = NO_ERROR);
930 if not Succeeded then
934 -- Set the new thread's priority
935 -- (child has inherited priority from parent)
937 Set_Priority (T, Priority);
939 -- Start the thread executing
941 Must_Not_Fail (DosResumeThread (T.Common.LL.Thread));
949 procedure Finalize_TCB (T : Task_Id) is
952 procedure Free is new
953 Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
956 Must_Not_Fail (DosCloseEventSem (T.Common.LL.CV));
958 if not Single_Lock then
959 Finalize_Lock (T.Common.LL.L'Unchecked_Access);
962 if T.Known_Tasks_Index /= -1 then
963 Known_Tasks (T.Known_Tasks_Index) := null;
973 procedure Exit_Task is
975 Thread_Local_Data_Ptr := null;
982 procedure Abort_Task (T : Task_Id) is
983 pragma Unreferenced (T);
988 -- Task abort not implemented yet.
989 -- Should perform other action ???
997 procedure Initialize (S : in out Suspension_Object) is
998 Result : Interfaces.C.int;
1000 -- Initialize internal state. It is always initialized to False (ARM
1006 -- Initialize internal mutex
1007 if DosCreateMutexSem
1008 (ICS.Null_Ptr, S.L'Unchecked_Access, 0, False32) /= NO_ERROR
1010 raise Storage_Error;
1013 pragma Assert (S.L /= 0, "Error creating Mutex");
1015 -- Initialize internal condition variable
1017 if DosCreateEventSem
1018 (ICS.Null_Ptr, S.CV'Unchecked_Access, 0, True32) /= NO_ERROR
1020 Must_Not_Fail (DosCloseMutexSem (S.L));
1022 raise Storage_Error;
1025 pragma Assert (S.CV /= 0, "Error creating Condition Variable");
1032 procedure Finalize (S : in out Suspension_Object) is
1034 -- Destroy internal mutex
1036 Must_Not_Fail (DosCloseMutexSem (S.L'Access));
1038 -- Destroy internal condition variable
1040 Must_Not_Fail (DosCloseEventSem (S.CV'Access));
1047 function Current_State (S : Suspension_Object) return Boolean is
1049 -- We do not want to use lock on this read operation. State is marked
1050 -- as Atomic so that we ensure that the value retrieved is correct.
1059 procedure Set_False (S : in out Suspension_Object) is
1061 Must_Not_Fail (DosRequestMutexSem (S.L, SEM_INDEFINITE_WAIT));
1065 Must_Not_Fail (DosReleaseMutexSem (S.L));
1072 procedure Set_True (S : in out Suspension_Object) is
1074 Must_Not_Fail (DosRequestMutexSem (S.L, SEM_INDEFINITE_WAIT));
1076 -- If there is already a task waiting on this suspension object then
1077 -- we resume it, leaving the state of the suspension object to False,
1078 -- as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
1079 -- the state to True.
1085 Sem_Must_Not_Fail (DosPostEventSem (S.CV));
1090 Must_Not_Fail (DosReleaseMutexSem (S.L));
1093 ------------------------
1094 -- Suspend_Until_True --
1095 ------------------------
1097 procedure Suspend_Until_True (S : in out Suspension_Object) is
1098 Count : aliased ULONG; -- Used to store dummy result
1100 Must_Not_Fail (DosRequestMutexSem (S.L, SEM_INDEFINITE_WAIT));
1103 -- Program_Error must be raised upon calling Suspend_Until_True
1104 -- if another task is already waiting on that suspension object
1105 -- (ARM D.10 par. 10).
1107 Must_Not_Fail (DosReleaseMutexSem (S.L));
1109 raise Program_Error;
1111 -- Suspend the task if the state is False. Otherwise, the task
1112 -- continues its execution, and the state of the suspension object
1113 -- is set to False (ARM D.10 par. 9).
1118 Must_Not_Fail (DosReleaseMutexSem (S.L));
1122 -- Must reset Cond BEFORE L is unlocked
1125 (DosResetEventSem (S.CV, Count'Unchecked_Access));
1127 Must_Not_Fail (DosReleaseMutexSem (S.L));
1130 (DosWaitEventSem (S.CV, SEM_INDEFINITE_WAIT));
1133 end Suspend_Until_True;
1141 function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
1143 return Check_No_Locks (Self_ID);
1146 --------------------
1147 -- Check_No_Locks --
1148 --------------------
1150 function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
1151 TLD : constant Access_Thread_Local_Data := Thread_Local_Data_Ptr;
1153 return Self_ID = TLD.Self_ID
1154 and then TLD.Lock_Prio_Level = 0;
1157 ----------------------
1158 -- Environment_Task --
1159 ----------------------
1161 function Environment_Task return Task_Id is
1163 return Environment_Task_Id;
1164 end Environment_Task;
1170 procedure Lock_RTS is
1172 Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1179 procedure Unlock_RTS is
1181 Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1188 function Suspend_Task
1190 Thread_Self : Thread_Id) return Boolean
1193 if Thread_Id (T.Common.LL.Thread) /= Thread_Self then
1194 return DosSuspendThread (T.Common.LL.Thread) = NO_ERROR;
1204 function Resume_Task
1206 Thread_Self : Thread_Id) return Boolean
1209 if Thread_Id (T.Common.LL.Thread) /= Thread_Self then
1210 return DosResumeThread (T.Common.LL.Thread) = NO_ERROR;
1220 procedure Initialize (Environment_Task : Task_Id) is
1221 Succeeded : Boolean;
1223 Environment_Task_Id := Environment_Task;
1225 OS_Primitives.Initialize;
1227 -- Initialize pointer to task local data.
1228 -- This is done once, for all tasks.
1230 Must_Not_Fail (DosAllocThreadLocalMemory
1231 ((Thread_Local_Data'Size + 31) / 32, -- nr of 32-bit words
1232 To_PPVOID (Thread_Local_Data_Ptr'Access)));
1234 -- Initialize thread local data for main thread
1236 Thread_Local_Data_Ptr.Self_ID := null;
1237 Thread_Local_Data_Ptr.Lock_Prio_Level := 0;
1239 Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
1240 -- Initialize the lock used to synchronize chain of all ATCBs
1242 -- Set ID of environment task
1244 Thread_Local_Data_Ptr.Self_ID := Environment_Task;
1245 Environment_Task.Common.LL.Thread := 1; -- By definition
1247 -- This priority is unknown in fact.
1248 -- If actual current priority is different,
1249 -- it will get synchronized later on anyway.
1251 Environment_Task.Common.LL.Current_Priority :=
1252 Environment_Task.Common.Current_Priority;
1254 -- Initialize TCB for this task.
1255 -- This includes all the normal task-external initialization.
1256 -- This is also done by Initialize_ATCB, why ???
1258 Initialize_TCB (Environment_Task, Succeeded);
1260 -- Consider raising Storage_Error,
1261 -- if propagation can be tolerated ???
1263 pragma Assert (Succeeded);
1265 -- Do normal task-internal initialization,
1266 -- which depends on an initialized TCB.
1268 Enter_Task (Environment_Task);
1270 -- Insert here any other special
1271 -- initialization needed for the environment task.
1274 end System.Task_Primitives.Operations;