------------------------------------------------------------------------------ -- -- -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS -- -- -- -- 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 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2004, Free Software Foundation, Inc. -- -- -- -- GNARL is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNARL is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNARL; see file COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is a OpenVMS/Alpha version of this package -- This package contains all the GNULL primitives that interface directly -- with the underlying OS. pragma Polling (Off); -- Turn off polling, we do not want ATC polling to take place during -- tasking operations. It causes infinite loops and other problems. with System.Tasking.Debug; -- used for Known_Tasks with Interfaces.C; -- used for int -- size_t with System.Parameters; -- used for Size_Type with System.Tasking; -- used for Ada_Task_Control_Block -- Task_Id with System.Soft_Links; -- used for Defer/Undefer_Abort -- Set_Exc_Stack_Addr -- Note that we do not use System.Tasking.Initialization directly since -- this is a higher level package that we shouldn't depend on. For example -- when using the restricted run time, it is replaced by -- System.Tasking.Restricted.Stages. with System.OS_Primitives; -- used for Delay_Modes with Unchecked_Conversion; with Unchecked_Deallocation; package body System.Task_Primitives.Operations is use System.Tasking.Debug; use System.Tasking; use Interfaces.C; use System.OS_Interface; use System.Parameters; use System.OS_Primitives; use type System.OS_Primitives.OS_Time; package SSL renames System.Soft_Links; ---------------- -- Local Data -- ---------------- -- The followings are logically constants, but need to be initialized -- at run time. Single_RTS_Lock : aliased RTS_Lock; -- This is a lock to allow only one thread of control in the RTS at -- a time; it is used to execute in mutual exclusion from all other tasks. -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List ATCB_Key : aliased pthread_key_t; -- Key used to find the Ada Task_Id associated with a thread Environment_Task_Id : Task_Id; -- A variable to hold Task_Id for the environment task. Time_Slice_Val : Integer; pragma Import (C, Time_Slice_Val, "__gl_time_slice_val"); Dispatching_Policy : Character; pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy"); FIFO_Within_Priorities : constant Boolean := Dispatching_Policy = 'F'; -- Indicates whether FIFO_Within_Priorities is set. Foreign_Task_Elaborated : aliased Boolean := True; -- Used to identified fake tasks (i.e., non-Ada Threads). -------------------- -- Local Packages -- -------------------- package Specific is procedure Initialize (Environment_Task : Task_Id); pragma Inline (Initialize); -- Initialize various data needed by this package. function Is_Valid_Task return Boolean; pragma Inline (Is_Valid_Task); -- Does executing thread have a TCB? procedure Set (Self_Id : Task_Id); pragma Inline (Set); -- Set the self id for the current task function Self return Task_Id; pragma Inline (Self); -- Return a pointer to the Ada Task Control Block of the calling task end Specific; package body Specific is separate; -- The body of this package is target specific. --------------------------------- -- Support for foreign threads -- --------------------------------- function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id; -- Allocate and Initialize a new ATCB for the current Thread function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id is separate; ----------------------- -- Local Subprograms -- ----------------------- function To_Task_Id is new Unchecked_Conversion (System.Address, Task_Id); function To_Address is new Unchecked_Conversion (Task_Id, System.Address); procedure Timer_Sleep_AST (ID : Address); -- Signal the condition variable when AST fires. procedure Timer_Sleep_AST (ID : Address) is Result : Interfaces.C.int; Self_ID : constant Task_Id := To_Task_Id (ID); begin Self_ID.Common.LL.AST_Pending := False; Result := pthread_cond_signal_int_np (Self_ID.Common.LL.CV'Access); pragma Assert (Result = 0); end Timer_Sleep_AST; ----------------- -- Stack_Guard -- ----------------- -- The underlying thread system sets a guard page at the -- bottom of a thread stack, so nothing is needed. -- ??? Check the comment above procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is pragma Unreferenced (T); pragma Unreferenced (On); begin null; end Stack_Guard; -------------------- -- Get_Thread_Id -- -------------------- function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is begin return T.Common.LL.Thread; end Get_Thread_Id; ---------- -- Self -- ---------- function Self return Task_Id renames Specific.Self; --------------------- -- Initialize_Lock -- --------------------- -- Note: mutexes and cond_variables needed per-task basis are -- initialized in Initialize_TCB and the Storage_Error is -- handled. Other mutexes (such as RTS_Lock, Memory_Lock...) -- used in RTS is initialized before any status change of RTS. -- Therefore rasing Storage_Error in the following routines -- should be able to be handled safely. procedure Initialize_Lock (Prio : System.Any_Priority; L : access Lock) is Attributes : aliased pthread_mutexattr_t; Result : Interfaces.C.int; begin Result := pthread_mutexattr_init (Attributes'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then raise Storage_Error; end if; L.Prio_Save := 0; L.Prio := Interfaces.C.int (Prio); Result := pthread_mutex_init (L.L'Access, Attributes'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then raise Storage_Error; end if; Result := pthread_mutexattr_destroy (Attributes'Access); pragma Assert (Result = 0); end Initialize_Lock; procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is pragma Unreferenced (Level); Attributes : aliased pthread_mutexattr_t; Result : Interfaces.C.int; begin Result := pthread_mutexattr_init (Attributes'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then raise Storage_Error; end if; -- Don't use, see comment in s-osinte.ads about ERRORCHECK mutexes??? -- Result := pthread_mutexattr_settype_np -- (Attributes'Access, PTHREAD_MUTEX_ERRORCHECK_NP); -- pragma Assert (Result = 0); -- Result := pthread_mutexattr_setprotocol -- (Attributes'Access, PTHREAD_PRIO_PROTECT); -- pragma Assert (Result = 0); -- Result := pthread_mutexattr_setprioceiling -- (Attributes'Access, Interfaces.C.int (System.Any_Priority'Last)); -- pragma Assert (Result = 0); Result := pthread_mutex_init (L, Attributes'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then raise Storage_Error; end if; Result := pthread_mutexattr_destroy (Attributes'Access); pragma Assert (Result = 0); end Initialize_Lock; ------------------- -- Finalize_Lock -- ------------------- procedure Finalize_Lock (L : access Lock) is Result : Interfaces.C.int; begin Result := pthread_mutex_destroy (L.L'Access); pragma Assert (Result = 0); end Finalize_Lock; procedure Finalize_Lock (L : access RTS_Lock) is Result : Interfaces.C.int; begin Result := pthread_mutex_destroy (L); pragma Assert (Result = 0); end Finalize_Lock; ---------------- -- Write_Lock -- ---------------- procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is Self_ID : constant Task_Id := Self; All_Tasks_Link : constant Task_Id := Self.Common.All_Tasks_Link; Current_Prio : System.Any_Priority; Result : Interfaces.C.int; begin Current_Prio := Get_Priority (Self_ID); -- If there is no other tasks, no need to check priorities if All_Tasks_Link /= Null_Task and then L.Prio < Interfaces.C.int (Current_Prio) then Ceiling_Violation := True; return; end if; Result := pthread_mutex_lock (L.L'Access); pragma Assert (Result = 0); Ceiling_Violation := False; -- Why is this commented out ??? -- L.Prio_Save := Interfaces.C.int (Current_Prio); -- Set_Priority (Self_ID, System.Any_Priority (L.Prio)); end Write_Lock; procedure Write_Lock (L : access RTS_Lock; Global_Lock : Boolean := False) is Result : Interfaces.C.int; begin if not Single_Lock or else Global_Lock then Result := pthread_mutex_lock (L); pragma Assert (Result = 0); end if; end Write_Lock; procedure Write_Lock (T : Task_Id) is Result : Interfaces.C.int; begin if not Single_Lock then Result := pthread_mutex_lock (T.Common.LL.L'Access); pragma Assert (Result = 0); end if; end Write_Lock; --------------- -- Read_Lock -- --------------- procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is begin Write_Lock (L, Ceiling_Violation); end Read_Lock; ------------ -- Unlock -- ------------ procedure Unlock (L : access Lock) is Result : Interfaces.C.int; begin Result := pthread_mutex_unlock (L.L'Access); pragma Assert (Result = 0); end Unlock; procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is Result : Interfaces.C.int; begin if not Single_Lock or else Global_Lock then Result := pthread_mutex_unlock (L); pragma Assert (Result = 0); end if; end Unlock; procedure Unlock (T : Task_Id) is Result : Interfaces.C.int; begin if not Single_Lock then Result := pthread_mutex_unlock (T.Common.LL.L'Access); pragma Assert (Result = 0); end if; end Unlock; ----------- -- Sleep -- ----------- procedure Sleep (Self_ID : Task_Id; Reason : System.Tasking.Task_States) is pragma Unreferenced (Reason); Result : Interfaces.C.int; begin if Single_Lock then Result := pthread_cond_wait (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access); else Result := pthread_cond_wait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access); end if; -- EINTR is not considered a failure pragma Assert (Result = 0 or else Result = EINTR); if Self_ID.Deferral_Level = 0 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then Unlock (Self_ID); raise Standard'Abort_Signal; end if; end Sleep; ----------------- -- Timed_Sleep -- ----------------- procedure Timed_Sleep (Self_ID : Task_Id; Time : Duration; Mode : ST.Delay_Modes; Reason : System.Tasking.Task_States; Timedout : out Boolean; Yielded : out Boolean) is pragma Unreferenced (Reason); Sleep_Time : OS_Time; Result : Interfaces.C.int; Status : Cond_Value_Type; -- The body below requires more comments ??? begin Timedout := False; Yielded := False; Sleep_Time := To_OS_Time (Time, Mode); if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level or else Self_ID.Pending_Priority_Change then return; end if; Self_ID.Common.LL.AST_Pending := True; Sys_Setimr (Status, 0, Sleep_Time, Timer_Sleep_AST'Access, To_Address (Self_ID), 0); if (Status and 1) /= 1 then raise Storage_Error; end if; if Single_Lock then Result := pthread_cond_wait (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access); pragma Assert (Result = 0); else Result := pthread_cond_wait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access); pragma Assert (Result = 0); end if; Yielded := True; if not Self_ID.Common.LL.AST_Pending then Timedout := True; else Sys_Cantim (Status, To_Address (Self_ID), 0); pragma Assert ((Status and 1) = 1); end if; end Timed_Sleep; ----------------- -- Timed_Delay -- ----------------- procedure Timed_Delay (Self_ID : Task_Id; Time : Duration; Mode : ST.Delay_Modes) is Sleep_Time : OS_Time; Result : Interfaces.C.int; Status : Cond_Value_Type; Yielded : Boolean := False; begin -- Only the little window between deferring abort and -- locking Self_ID is the reason we need to -- check for pending abort and priority change below! if Single_Lock then Lock_RTS; end if; -- More comments required in body below ??? SSL.Abort_Defer.all; Write_Lock (Self_ID); if Time /= 0.0 or else Mode /= Relative then Sleep_Time := To_OS_Time (Time, Mode); if Mode = Relative or else OS_Clock < Sleep_Time then Self_ID.Common.State := Delay_Sleep; Self_ID.Common.LL.AST_Pending := True; Sys_Setimr (Status, 0, Sleep_Time, Timer_Sleep_AST'Access, To_Address (Self_ID), 0); if (Status and 1) /= 1 then raise Storage_Error; end if; loop if Self_ID.Pending_Priority_Change then Self_ID.Pending_Priority_Change := False; Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority; Set_Priority (Self_ID, Self_ID.Common.Base_Priority); end if; if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then Sys_Cantim (Status, To_Address (Self_ID), 0); pragma Assert ((Status and 1) = 1); exit; end if; if Single_Lock then Result := pthread_cond_wait (Self_ID.Common.LL.CV'Access, Single_RTS_Lock'Access); pragma Assert (Result = 0); else Result := pthread_cond_wait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access); pragma Assert (Result = 0); end if; Yielded := True; exit when not Self_ID.Common.LL.AST_Pending; end loop; Self_ID.Common.State := Runnable; end if; end if; Unlock (Self_ID); if Single_Lock then Unlock_RTS; end if; if not Yielded then Result := sched_yield; pragma Assert (Result = 0); end if; SSL.Abort_Undefer.all; end Timed_Delay; --------------------- -- Monotonic_Clock -- --------------------- function Monotonic_Clock return Duration renames System.OS_Primitives.Monotonic_Clock; ------------------- -- RT_Resolution -- ------------------- function RT_Resolution return Duration is begin return 10#1.0#E-3; end RT_Resolution; ------------ -- Wakeup -- ------------ procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is pragma Unreferenced (Reason); Result : Interfaces.C.int; begin Result := pthread_cond_signal (T.Common.LL.CV'Access); pragma Assert (Result = 0); end Wakeup; ----------- -- Yield -- ----------- procedure Yield (Do_Yield : Boolean := True) is Result : Interfaces.C.int; pragma Unreferenced (Result); begin if Do_Yield then Result := sched_yield; end if; end Yield; ------------------ -- Set_Priority -- ------------------ procedure Set_Priority (T : Task_Id; Prio : System.Any_Priority; Loss_Of_Inheritance : Boolean := False) is pragma Unreferenced (Loss_Of_Inheritance); Result : Interfaces.C.int; Param : aliased struct_sched_param; begin T.Common.Current_Priority := Prio; Param.sched_priority := Interfaces.C.int (Underlying_Priorities (Prio)); if Time_Slice_Val > 0 then Result := pthread_setschedparam (T.Common.LL.Thread, SCHED_RR, Param'Access); elsif FIFO_Within_Priorities or else Time_Slice_Val = 0 then Result := pthread_setschedparam (T.Common.LL.Thread, SCHED_FIFO, Param'Access); else -- SCHED_OTHER priorities are restricted to the range 8 - 15. -- Since the translation from Underlying priorities results -- in a range of 16 - 31, dividing by 2 gives the correct result. Param.sched_priority := Param.sched_priority / 2; Result := pthread_setschedparam (T.Common.LL.Thread, SCHED_OTHER, Param'Access); end if; pragma Assert (Result = 0); end Set_Priority; ------------------ -- Get_Priority -- ------------------ function Get_Priority (T : Task_Id) return System.Any_Priority is begin return T.Common.Current_Priority; end Get_Priority; ---------------- -- Enter_Task -- ---------------- procedure Enter_Task (Self_ID : Task_Id) is begin Self_ID.Common.LL.Thread := pthread_self; Specific.Set (Self_ID); Lock_RTS; for J in Known_Tasks'Range loop if Known_Tasks (J) = null then Known_Tasks (J) := Self_ID; Self_ID.Known_Tasks_Index := J; exit; end if; end loop; Unlock_RTS; end Enter_Task; -------------- -- New_ATCB -- -------------- function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is begin return new Ada_Task_Control_Block (Entry_Num); end New_ATCB; ------------------- -- Is_Valid_Task -- ------------------- function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task; ----------------------------- -- Register_Foreign_Thread -- ----------------------------- function Register_Foreign_Thread return Task_Id is begin if Is_Valid_Task then return Self; else return Register_Foreign_Thread (pthread_self); end if; end Register_Foreign_Thread; -------------------- -- Initialize_TCB -- -------------------- procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is Mutex_Attr : aliased pthread_mutexattr_t; Result : Interfaces.C.int; Cond_Attr : aliased pthread_condattr_t; begin -- More comments required in body below ??? if not Single_Lock then Result := pthread_mutexattr_init (Mutex_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = 0 then Result := pthread_mutex_init (Self_ID.Common.LL.L'Access, Mutex_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); end if; if Result /= 0 then Succeeded := False; return; end if; Result := pthread_mutexattr_destroy (Mutex_Attr'Access); pragma Assert (Result = 0); end if; Result := pthread_condattr_init (Cond_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = 0 then Result := pthread_cond_init (Self_ID.Common.LL.CV'Access, Cond_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); end if; if Result = 0 then Succeeded := True; Self_ID.Common.LL.Exc_Stack_Ptr := new Exc_Stack_T; SSL.Set_Exc_Stack_Addr (To_Address (Self_ID), Self_ID.Common.LL.Exc_Stack_Ptr (Exc_Stack_T'Last)'Address); else if not Single_Lock then Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access); pragma Assert (Result = 0); end if; Succeeded := False; end if; Result := pthread_condattr_destroy (Cond_Attr'Access); pragma Assert (Result = 0); end Initialize_TCB; ----------------- -- Create_Task -- ----------------- procedure Create_Task (T : Task_Id; Wrapper : System.Address; Stack_Size : System.Parameters.Size_Type; Priority : System.Any_Priority; Succeeded : out Boolean) is Attributes : aliased pthread_attr_t; Adjusted_Stack_Size : Interfaces.C.size_t; Result : Interfaces.C.int; function Thread_Body_Access is new Unchecked_Conversion (System.Address, Thread_Body); begin if Stack_Size = Unspecified_Size then Adjusted_Stack_Size := Interfaces.C.size_t (Default_Stack_Size); elsif Stack_Size < Minimum_Stack_Size then Adjusted_Stack_Size := Interfaces.C.size_t (Minimum_Stack_Size); else Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size); end if; -- Since the initial signal mask of a thread is inherited from the -- creator, we need to set our local signal mask mask all signals -- during the creation operation, to make sure the new thread is -- not disturbed by signals before it has set its own Task_Id. Result := pthread_attr_init (Attributes'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result /= 0 then Succeeded := False; return; end if; Result := pthread_attr_setdetachstate (Attributes'Access, PTHREAD_CREATE_DETACHED); pragma Assert (Result = 0); Result := pthread_attr_setstacksize (Attributes'Access, Adjusted_Stack_Size); pragma Assert (Result = 0); -- This call may be unnecessary, not sure. ??? Result := pthread_attr_setinheritsched (Attributes'Access, PTHREAD_EXPLICIT_SCHED); pragma Assert (Result = 0); Result := pthread_create (T.Common.LL.Thread'Access, Attributes'Access, Thread_Body_Access (Wrapper), To_Address (T)); -- ENOMEM is a valid run-time error. Don't shut down. pragma Assert (Result = 0 or else Result = EAGAIN or else Result = ENOMEM); Succeeded := Result = 0; Result := pthread_attr_destroy (Attributes'Access); pragma Assert (Result = 0); if Succeeded then Set_Priority (T, Priority); end if; end Create_Task; ------------------ -- Finalize_TCB -- ------------------ procedure Finalize_TCB (T : Task_Id) is Result : Interfaces.C.int; Tmp : Task_Id := T; Is_Self : constant Boolean := T = Self; procedure Free is new Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id); procedure Free is new Unchecked_Deallocation (Exc_Stack_T, Exc_Stack_Ptr_T); begin if not Single_Lock then Result := pthread_mutex_destroy (T.Common.LL.L'Access); pragma Assert (Result = 0); end if; Result := pthread_cond_destroy (T.Common.LL.CV'Access); pragma Assert (Result = 0); if T.Known_Tasks_Index /= -1 then Known_Tasks (T.Known_Tasks_Index) := null; end if; Free (T.Common.LL.Exc_Stack_Ptr); Free (Tmp); if Is_Self then Specific.Set (null); end if; end Finalize_TCB; --------------- -- Exit_Task -- --------------- procedure Exit_Task is begin Specific.Set (null); end Exit_Task; ---------------- -- Abort_Task -- ---------------- procedure Abort_Task (T : Task_Id) is begin -- Interrupt Server_Tasks may be waiting on an event flag if T.Common.State = Interrupt_Server_Blocked_On_Event_Flag then Wakeup (T, Interrupt_Server_Blocked_On_Event_Flag); end if; end Abort_Task; ---------------- -- Check_Exit -- ---------------- -- Dummy version function Check_Exit (Self_ID : ST.Task_Id) return Boolean is pragma Unreferenced (Self_ID); begin return True; end Check_Exit; -------------------- -- Check_No_Locks -- -------------------- function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is pragma Unreferenced (Self_ID); begin return True; end Check_No_Locks; ---------------------- -- Environment_Task -- ---------------------- function Environment_Task return Task_Id is begin return Environment_Task_Id; end Environment_Task; -------------- -- Lock_RTS -- -------------- procedure Lock_RTS is begin Write_Lock (Single_RTS_Lock'Access, Global_Lock => True); end Lock_RTS; ---------------- -- Unlock_RTS -- ---------------- procedure Unlock_RTS is begin Unlock (Single_RTS_Lock'Access, Global_Lock => True); end Unlock_RTS; ------------------ -- Suspend_Task -- ------------------ function Suspend_Task (T : ST.Task_Id; Thread_Self : Thread_Id) return Boolean is pragma Unreferenced (T); pragma Unreferenced (Thread_Self); begin return False; end Suspend_Task; ----------------- -- Resume_Task -- ----------------- function Resume_Task (T : ST.Task_Id; Thread_Self : Thread_Id) return Boolean is pragma Unreferenced (T); pragma Unreferenced (Thread_Self); begin return False; end Resume_Task; ---------------- -- Initialize -- ---------------- procedure Initialize (Environment_Task : Task_Id) is begin Environment_Task_Id := Environment_Task; -- Initialize the lock used to synchronize chain of all ATCBs Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level); Specific.Initialize (Environment_Task); Enter_Task (Environment_Task); end Initialize; end System.Task_Primitives.Operations;