+++ /dev/null
-------------------------------------------------------------------------------
--- --
--- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
--- --
--- 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 --
--- --
--- B o d y --
--- --
--- $Revision: 1.1 $
--- --
--- Copyright (C) 1991-2001, Florida State University --
--- --
--- 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. It is --
--- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
--- State University (http://www.gnat.com). --
--- --
-------------------------------------------------------------------------------
-
-pragma Style_Checks (All_Checks);
--- Turn off subprogram alpha ordering check, since we group soft link
--- bodies and dummy soft link bodies together separately in this unit.
-
-pragma Polling (Off);
--- Turn polling off for this package. We don't need polling during any
--- of the routines in this package, and more to the point, if we try
--- to poll it can cause infinite loops.
-
--- This package provides overall initialization of the tasking portion
--- of the RTS. This package must be elaborated before any tasking
--- features are used. It also contains initialization for
--- Ada Task Control Block (ATCB) records.
-
-with Ada.Exceptions;
--- used for Exception_Occurrence_Access.
-
-with System.Tasking;
-pragma Elaborate_All (System.Tasking);
--- ensure that the first step initializations have been performed
-
-with System.Task_Primitives;
--- used for Lock
-
-with System.Task_Primitives.Operations;
--- used for Set_Priority
--- Write_Lock
--- Unlock
--- Initialize_Lock
-
-with System.Soft_Links;
--- used for the non-tasking routines (*_NT) that refer to global data.
--- They are needed here before the tasking run time has been elaborated.
-
-with System.Tasking.Debug;
--- used for Trace
-
-with System.Tasking.Task_Attributes;
--- used for All_Attrs_L
-
-with System.Stack_Checking;
-
-package body System.Tasking.Initialization is
-
- package STPO renames System.Task_Primitives.Operations;
- package SSL renames System.Soft_Links;
- package AE renames Ada.Exceptions;
-
- use System.Task_Primitives.Operations;
-
- Global_Task_Lock : aliased System.Task_Primitives.RTS_Lock;
- -- This is a global lock; it is used to execute in mutual exclusion
- -- from all other tasks. It is only used by Task_Lock,
- -- Task_Unlock, and Final_Task_Unlock.
-
- function Current_Target_Exception return AE.Exception_Occurrence;
- pragma Import
- (Ada, Current_Target_Exception, "__gnat_current_target_exception");
- -- Import this subprogram from the private part of Ada.Exceptions.
-
- -----------------------------------------------------------------
- -- Tasking versions of services needed by non-tasking programs --
- -----------------------------------------------------------------
-
- procedure Task_Lock;
- -- Locks out other tasks. Preceding a section of code by Task_Lock and
- -- following it by Task_Unlock creates a critical region. This is used
- -- for ensuring that a region of non-tasking code (such as code used to
- -- allocate memory) is tasking safe. Note that it is valid for calls to
- -- Task_Lock/Task_Unlock to be nested, and this must work properly, i.e.
- -- only the corresponding outer level Task_Unlock will actually unlock.
-
- procedure Task_Unlock;
- -- Releases lock previously set by call to Task_Lock. In the nested case,
- -- all nested locks must be released before other tasks competing for the
- -- tasking lock are released.
-
- function Get_Jmpbuf_Address return Address;
- procedure Set_Jmpbuf_Address (Addr : Address);
- -- Get/Set Jmpbuf_Address for current task
-
- function Get_Sec_Stack_Addr return Address;
- procedure Set_Sec_Stack_Addr (Addr : Address);
- -- Get/Set location of current task's secondary stack
-
- function Get_Exc_Stack_Addr return Address;
- -- Get the exception stack for the current task
-
- procedure Set_Exc_Stack_Addr (Self_ID : Address; Addr : Address);
- -- Self_ID is the Task_ID of the task that gets the exception stack.
- -- For Self_ID = Null_Address, the current task gets the exception stack.
-
- function Get_Machine_State_Addr return Address;
- procedure Set_Machine_State_Addr (Addr : Address);
- -- Get/Set the address for storing the current task's machine state
-
- function Get_Current_Excep return SSL.EOA;
- -- Comments needed???
-
- procedure Timed_Delay_T (Time : Duration; Mode : Integer);
- -- Comments needed???
-
- function Get_Stack_Info return Stack_Checking.Stack_Access;
- -- Get access to the current task's Stack_Info
-
- procedure Update_Exception
- (X : AE.Exception_Occurrence := Current_Target_Exception);
- -- Handle exception setting and check for pending actions
-
- ------------------------
- -- Local Subprograms --
- ------------------------
-
- procedure Do_Pending_Action (Self_ID : Task_ID);
- -- This is introduced to allow more efficient
- -- in-line expansion of Undefer_Abort.
-
- ----------------------------
- -- Tasking Initialization --
- ----------------------------
-
- procedure Init_RTS;
- -- This procedure completes the initialization of the GNARL. The first
- -- part of the initialization is done in the body of System.Tasking.
- -- It consists of initializing global locks, and installing tasking
- -- versions of certain operations used by the compiler. Init_RTS is called
- -- during elaboration.
-
- --------------------------
- -- Change_Base_Priority --
- --------------------------
-
- -- Call only with abort deferred and holding Self_ID locked.
-
- procedure Change_Base_Priority (T : Task_ID) is
- begin
- if T.Common.Base_Priority /= T.New_Base_Priority then
- T.Common.Base_Priority := T.New_Base_Priority;
- Set_Priority (T, T.Common.Base_Priority);
- end if;
- end Change_Base_Priority;
-
- ------------------------
- -- Check_Abort_Status --
- ------------------------
-
- function Check_Abort_Status return Integer is
- Self_ID : Task_ID := Self;
-
- begin
- if Self_ID /= null and then Self_ID.Deferral_Level = 0
- and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
- then
- return 1;
- else
- return 0;
- end if;
- end Check_Abort_Status;
-
- -----------------
- -- Defer_Abort --
- -----------------
-
- procedure Defer_Abort (Self_ID : Task_ID) is
- begin
-
- pragma Assert (Self_ID.Deferral_Level = 0);
-
--- pragma Assert
--- (Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level);
-
- -- The above check has been useful in detecting mismatched
- -- defer/undefer pairs. You may uncomment it when testing on
- -- systems that support preemptive abort.
-
- -- If the OS supports preemptive abort (e.g. pthread_kill),
- -- it should have happened already. A problem is with systems
- -- that do not support preemptive abort, and so rely on polling.
- -- On such systems we may get false failures of the assertion,
- -- since polling for pending abort does no occur until the abort
- -- undefer operation.
-
- -- Even on systems that only poll for abort, the assertion may
- -- be useful for catching missed abort completion polling points.
- -- The operations that undefer abort poll for pending aborts.
- -- This covers most of the places where the core Ada semantics
- -- require abort to be caught, without any special attention.
- -- However, this generally happens on exit from runtime system
- -- call, which means a pending abort will not be noticed on the
- -- way into the runtime system. We considered adding a check
- -- for pending aborts at this point, but chose not to, because
- -- of the overhead. Instead, we searched for RTS calls that
- -- where abort completion is required and a task could go
- -- farther than Ada allows before undeferring abort; we then
- -- modified the code to ensure the abort would be detected.
-
- Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
- end Defer_Abort;
-
- --------------------------
- -- Defer_Abort_Nestable --
- --------------------------
-
- procedure Defer_Abort_Nestable (Self_ID : Task_ID) is
- begin
-
--- pragma Assert
--- ((Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level or else
--- Self_ID.Deferral_Level > 0));
-
- -- See comment in Defer_Abort on the situations in which it may
- -- be useful to uncomment the above assertion.
-
- Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
- end Defer_Abort_Nestable;
-
- --------------------
- -- Defer_Abortion --
- --------------------
-
- -- ??????
- -- Phase out Defer_Abortion without Self_ID
- -- to reduce overhead due to multiple calls to Self
-
- procedure Defer_Abortion is
- Self_ID : constant Task_ID := STPO.Self;
-
- begin
- Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
- end Defer_Abortion;
-
- -----------------------
- -- Do_Pending_Action --
- -----------------------
-
- -- Call only when holding no locks
-
- procedure Do_Pending_Action (Self_ID : Task_ID) is
- use type Ada.Exceptions.Exception_Id;
-
- begin
- pragma Assert (Self_ID = Self and then Self_ID.Deferral_Level = 0);
-
- -- Needs loop to recheck for pending action in case a new one occurred
- -- while we had abort deferred below.
-
- loop
- -- Temporarily defer abortion so that we can lock Self_ID.
-
- Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
-
- Write_Lock (Self_ID);
- Self_ID.Pending_Action := False;
- Poll_Base_Priority_Change (Self_ID);
- Unlock (Self_ID);
-
- -- Restore the original Deferral value.
-
- Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1;
-
- if not Self_ID.Pending_Action then
- if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then
- if not Self_ID.Aborting then
- Self_ID.Aborting := True;
- pragma Debug
- (Debug.Trace (Self_ID, "raise Abort_Signal", 'B'));
- raise Standard'Abort_Signal;
-
- pragma Assert (not Self_ID.ATC_Hack);
-
- elsif Self_ID.ATC_Hack then
- -- The solution really belongs in the Abort_Signal handler
- -- for async. entry calls. The present hack is very
- -- fragile. It relies that the very next point after
- -- Exit_One_ATC_Level at which the task becomes abortable
- -- will be the call to Undefer_Abort in the
- -- Abort_Signal handler.
-
- Self_ID.ATC_Hack := False;
-
- pragma Debug
- (Debug.Trace
- (Self_ID, "raise Abort_Signal (ATC hack)", 'B'));
- raise Standard'Abort_Signal;
- end if;
- end if;
-
- return;
- end if;
- end loop;
- end Do_Pending_Action;
-
- -----------------------
- -- Final_Task_Unlock --
- -----------------------
-
- -- This version is only for use in Terminate_Task, when the task
- -- is relinquishing further rights to its own ATCB.
- -- There is a very interesting potential race condition there, where
- -- the old task may run concurrently with a new task that is allocated
- -- the old tasks (now reused) ATCB. The critical thing here is to
- -- not make any reference to the ATCB after the lock is released.
- -- See also comments on Terminate_Task and Unlock.
-
- procedure Final_Task_Unlock (Self_ID : Task_ID) is
- begin
- pragma Assert (Self_ID.Global_Task_Lock_Nesting = 1);
- Unlock (Global_Task_Lock'Access);
- end Final_Task_Unlock;
-
- --------------
- -- Init_RTS --
- --------------
-
- procedure Init_RTS is
- Self_Id : Task_ID;
- begin
- -- Terminate run time (regular vs restricted) specific initialization
- -- of the environment task.
-
- Self_Id := Environment_Task;
- Self_Id.Master_of_Task := Environment_Task_Level;
- Self_Id.Master_Within := Self_Id.Master_of_Task + 1;
-
- for L in Self_Id.Entry_Calls'Range loop
- Self_Id.Entry_Calls (L).Self := Self_Id;
- Self_Id.Entry_Calls (L).Level := L;
- end loop;
-
- Self_Id.Awake_Count := 1;
- Self_Id.Alive_Count := 1;
-
- Self_Id.Master_Within := Library_Task_Level;
- -- Normally, a task starts out with internal master nesting level
- -- one larger than external master nesting level. It is incremented
- -- to one by Enter_Master, which is called in the task body only if
- -- the compiler thinks the task may have dependent tasks. There is no
- -- corresponding call to Enter_Master for the environment task, so we
- -- would need to increment it to 2 here. Instead, we set it to 3.
- -- By doing this we reserve the level 2 for server tasks of the runtime
- -- system. The environment task does not need to wait for these server
-
- -- Initialize lock used to implement mutual exclusion between all tasks
-
- Initialize_Lock (Global_Task_Lock'Access, STPO.Global_Task_Level);
-
- -- Initialize lock used to implement mutual exclusion in the package
- -- System.Task_Attributes.
-
- Initialize_Lock (System.Tasking.Task_Attributes.All_Attrs_L'Access,
- All_Attrs_Level);
-
- -- Notify that the tasking run time has been elaborated so that
- -- the tasking version of the soft links can be used.
-
- SSL.Abort_Defer := Defer_Abortion'Access;
- SSL.Abort_Undefer := Undefer_Abortion'Access;
- SSL.Update_Exception := Update_Exception'Access;
- SSL.Lock_Task := Task_Lock'Access;
- SSL.Unlock_Task := Task_Unlock'Access;
- SSL.Get_Jmpbuf_Address := Get_Jmpbuf_Address'Access;
- SSL.Set_Jmpbuf_Address := Set_Jmpbuf_Address'Access;
- SSL.Get_Sec_Stack_Addr := Get_Sec_Stack_Addr'Access;
- SSL.Set_Sec_Stack_Addr := Set_Sec_Stack_Addr'Access;
- SSL.Get_Exc_Stack_Addr := Get_Exc_Stack_Addr'Access;
- SSL.Set_Exc_Stack_Addr := Set_Exc_Stack_Addr'Access;
- SSL.Get_Machine_State_Addr := Get_Machine_State_Addr'Access;
- SSL.Set_Machine_State_Addr := Set_Machine_State_Addr'Access;
- SSL.Get_Current_Excep := Get_Current_Excep'Access;
- SSL.Timed_Delay := Timed_Delay_T'Access;
- SSL.Check_Abort_Status := Check_Abort_Status'Access;
- SSL.Get_Stack_Info := Get_Stack_Info'Access;
-
- -- No need to create a new Secondary Stack, since we will use the
- -- default one created in s-secsta.adb
-
- SSL.Set_Sec_Stack_Addr (SSL.Get_Sec_Stack_Addr_NT);
- SSL.Set_Exc_Stack_Addr (Null_Address, SSL.Get_Exc_Stack_Addr_NT);
- SSL.Set_Jmpbuf_Address (SSL.Get_Jmpbuf_Address_NT);
- SSL.Set_Machine_State_Addr (SSL.Get_Machine_State_Addr_NT);
-
- -- Abortion is deferred in a new ATCB, so we need to undefer abortion
- -- at this stage to make the environment task abortable.
-
- Undefer_Abort (Environment_Task);
- end Init_RTS;
-
- ---------------------------
- -- Locked_Abort_To_Level--
- ---------------------------
-
- -- Abort a task to the specified ATC nesting level.
- -- Call this only with T locked.
-
- -- An earlier version of this code contained a call to Wakeup. That
- -- should not be necessary here, if Abort_Task is implemented correctly,
- -- since Abort_Task should include the effect of Wakeup. However, the
- -- above call was in earlier versions of this file, and at least for
- -- some targets Abort_Task has not beek doing Wakeup. It should not
- -- hurt to uncomment the above call, until the error is corrected for
- -- all targets.
-
- -- See extended comments in package body System.Tasking.Abortion
- -- for the overall design of the implementation of task abort.
-
- -- If the task is sleeping it will be in an abort-deferred region,
- -- and will not have Abort_Signal raised by Abort_Task.
- -- Such an "abort deferral" is just to protect the RTS internals,
- -- and not necessarily required to enforce Ada semantics.
- -- Abort_Task should wake the task up and let it decide if it wants
- -- to complete the aborted construct immediately.
-
- -- Note that the effect of the lowl-level Abort_Task is not persistent.
- -- If the target task is not blocked, this wakeup will be missed.
-
- -- We don't bother calling Abort_Task if this task is aborting itself,
- -- since we are inside the RTS and have abort deferred. Similarly, We
- -- don't bother to call Abort_Task if T is terminated, since there is
- -- no need to abort a terminated task, and it could be dangerous to try
- -- if the task has stopped executing.
-
- -- Note that an earlier version of this code had some false reasoning
- -- about being able to reliably wake up a task that had suspended on
- -- a blocking system call that does not atomically relase the task's
- -- lock (e.g., UNIX nanosleep, which we once thought could be used to
- -- implement delays). That still left the possibility of missed
- -- wakeups.
-
- -- We cannot safely call Vulnerable_Complete_Activation here,
- -- since that requires locking Self_ID.Parent. The anti-deadlock
- -- lock ordering rules would then require us to release the lock
- -- on Self_ID first, which would create a timing window for other
- -- tasks to lock Self_ID. This is significant for tasks that may be
- -- aborted before their execution can enter the task body, and so
- -- they do not get a chance to call Complete_Task. The actual work
- -- for this case is done in Terminate_Task.
-
- procedure Locked_Abort_To_Level
- (Self_ID : Task_ID;
- T : Task_ID;
- L : ATC_Level) is
-
- begin
- if not T.Aborting and then T /= Self_ID then
- case T.Common.State is
- when Unactivated | Terminated =>
- pragma Assert (False);
- null;
-
- when Runnable =>
- -- This is needed to cancel an asynchronous protected entry
- -- call during a requeue with abort.
-
- T.Entry_Calls
- (T.ATC_Nesting_Level).Cancellation_Attempted := True;
-
- when Interrupt_Server_Blocked_On_Event_Flag =>
- null;
-
- when Delay_Sleep |
- Async_Select_Sleep |
- Interrupt_Server_Idle_Sleep |
- Interrupt_Server_Blocked_Interrupt_Sleep |
- Timer_Server_Sleep |
- AST_Server_Sleep =>
- Wakeup (T, T.Common.State);
-
- when Acceptor_Sleep =>
- T.Open_Accepts := null;
- Wakeup (T, T.Common.State);
-
- when Entry_Caller_Sleep =>
- T.Entry_Calls
- (T.ATC_Nesting_Level).Cancellation_Attempted := True;
- Wakeup (T, T.Common.State);
-
- when Activator_Sleep |
- Master_Completion_Sleep |
- Master_Phase_2_Sleep |
- Asynchronous_Hold =>
- null;
- end case;
- end if;
-
- if T.Pending_ATC_Level > L then
- T.Pending_ATC_Level := L;
- T.Pending_Action := True;
-
- if L = 0 then
- T.Callable := False;
- end if;
-
- -- This prevents aborted task from accepting calls
-
- if T.Aborting then
-
- -- The test above is just a heuristic, to reduce wasteful
- -- calls to Abort_Task. We are holding T locked, and this
- -- value will not be set to False except with T also locked,
- -- inside Exit_One_ATC_Level, so we should not miss wakeups.
-
- if T.Common.State = Acceptor_Sleep then
- T.Open_Accepts := null;
- end if;
-
- elsif T /= Self_ID and then
- (T.Common.State = Runnable
- or else T.Common.State = Interrupt_Server_Blocked_On_Event_Flag)
- -- The task is blocked on a system call waiting for the
- -- completion event. In this case Abort_Task may need to take
- -- special action in order to succeed. Example system: VMS.
-
- then
- Abort_Task (T);
- end if;
- end if;
- end Locked_Abort_To_Level;
-
- -------------------------------
- -- Poll_Base_Priority_Change --
- -------------------------------
-
- -- Poll for pending base priority change and for held tasks.
- -- This should always be called with (only) Self_ID locked.
- -- It may temporarily release Self_ID's lock.
-
- -- The call to Yield is to force enqueuing at the
- -- tail of the dispatching queue.
-
- -- We must unlock Self_ID for this to take effect,
- -- since we are inheriting high active priority from the lock.
-
- -- See also Poll_Base_Priority_Change_At_Entry_Call,
- -- in package System.Tasking.Entry_Calls.
-
- -- In this version, we check if the task is held too because
- -- doing this only in Do_Pending_Action is not enough.
-
- procedure Poll_Base_Priority_Change (Self_ID : Task_ID) is
- begin
- if Dynamic_Priority_Support
- and then Self_ID.Pending_Priority_Change
- then
- -- Check for ceiling violations ???
-
- Self_ID.Pending_Priority_Change := False;
-
- if Self_ID.Common.Base_Priority = Self_ID.New_Base_Priority then
- Unlock (Self_ID);
- Yield;
- Write_Lock (Self_ID);
-
- elsif Self_ID.Common.Base_Priority < Self_ID.New_Base_Priority then
- Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
- Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
-
- else
- -- Lowering priority
-
- Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
- Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
- Unlock (Self_ID);
- Yield;
- Write_Lock (Self_ID);
- end if;
- end if;
- end Poll_Base_Priority_Change;
-
- --------------------------------
- -- Remove_From_All_Tasks_List --
- --------------------------------
-
- procedure Remove_From_All_Tasks_List (T : Task_ID) is
- C : Task_ID;
- Previous : Task_ID;
-
- begin
- pragma Debug
- (Debug.Trace ("Remove_From_All_Tasks_List", 'C'));
-
- Lock_All_Tasks_List;
-
- Previous := Null_Task;
- C := All_Tasks_List;
- while C /= Null_Task loop
- if C = T then
- if Previous = Null_Task then
- All_Tasks_List :=
- All_Tasks_List.Common.All_Tasks_Link;
- else
- Previous.Common.All_Tasks_Link := C.Common.All_Tasks_Link;
- end if;
-
- Unlock_All_Tasks_List;
- return;
- end if;
-
- Previous := C;
- C := C.Common.All_Tasks_Link;
- end loop;
-
- pragma Assert (False);
- end Remove_From_All_Tasks_List;
-
- ---------------
- -- Task_Lock --
- ---------------
-
- procedure Task_Lock is
- T : Task_ID := STPO.Self;
-
- begin
- T.Global_Task_Lock_Nesting := T.Global_Task_Lock_Nesting + 1;
-
- if T.Global_Task_Lock_Nesting = 1 then
- Defer_Abort_Nestable (T);
- Write_Lock (Global_Task_Lock'Access);
- end if;
- end Task_Lock;
-
- procedure Task_Lock (Self_ID : Task_ID) is
- begin
- Self_ID.Global_Task_Lock_Nesting := Self_ID.Global_Task_Lock_Nesting + 1;
-
- if Self_ID.Global_Task_Lock_Nesting = 1 then
- Defer_Abort_Nestable (Self_ID);
- Write_Lock (Global_Task_Lock'Access);
- end if;
- end Task_Lock;
-
- -----------------
- -- Task_Unlock --
- -----------------
-
- procedure Task_Unlock is
- T : Task_ID := STPO.Self;
-
- begin
- pragma Assert (T.Global_Task_Lock_Nesting > 0);
-
- T.Global_Task_Lock_Nesting := T.Global_Task_Lock_Nesting - 1;
-
- if T.Global_Task_Lock_Nesting = 0 then
- Unlock (Global_Task_Lock'Access);
- Undefer_Abort_Nestable (T);
- end if;
- end Task_Unlock;
-
- procedure Task_Unlock (Self_ID : Task_ID) is
- begin
- Self_ID.Global_Task_Lock_Nesting := Self_ID.Global_Task_Lock_Nesting - 1;
-
- if Self_ID.Global_Task_Lock_Nesting = 0 then
- Unlock (Global_Task_Lock'Access);
- Undefer_Abort_Nestable (Self_ID);
- end if;
- end Task_Unlock;
-
- -------------------
- -- Undefer_Abort --
- -------------------
-
- -- Precondition : Self does not hold any locks!
-
- -- Undefer_Abort is called on any abortion completion point (aka.
- -- synchronization point). It performs the following actions if they
- -- are pending: (1) change the base priority, (2) abort the task,
- -- (3) raise a pending exception.
-
- -- The priority change has to occur before abortion. Otherwise, it would
- -- take effect no earlier than the next abortion completion point.
-
- procedure Undefer_Abort (Self_ID : Task_ID) is
- begin
- pragma Assert (Self_ID.Deferral_Level = 1);
-
- Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1;
-
- if Self_ID.Deferral_Level = 0 then
- pragma Assert (Check_No_Locks (Self_ID));
-
- if Self_ID.Pending_Action then
- Do_Pending_Action (Self_ID);
- end if;
- end if;
- end Undefer_Abort;
-
- ----------------------------
- -- Undefer_Abort_Nestable --
- ----------------------------
-
- -- An earlier version would re-defer abort if an abort is
- -- in progress. Then, we modified the effect of the raise
- -- statement so that it defers abort until control reaches a
- -- handler. That was done to prevent "skipping over" a
- -- handler if another asynchronous abort occurs during the
- -- propagation of the abort to the handler.
-
- -- There has been talk of reversing that decision, based on
- -- a newer implementation of exception propagation. Care must
- -- be taken to evaluate how such a change would interact with
- -- the above code and all the places where abort-deferral is
- -- used to bridge over critical transitions, such as entry to
- -- the scope of a region with a finalizer and entry into the
- -- body of an accept-procedure.
-
- procedure Undefer_Abort_Nestable (Self_ID : Task_ID) is
- begin
- pragma Assert (Self_ID.Deferral_Level > 0);
-
- Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1;
-
- if Self_ID.Deferral_Level = 0 then
-
- pragma Assert (Check_No_Locks (Self_ID));
-
- if Self_ID.Pending_Action then
- Do_Pending_Action (Self_ID);
- end if;
- end if;
- end Undefer_Abort_Nestable;
-
- ----------------------
- -- Undefer_Abortion --
- ----------------------
-
- -- Phase out RTS-internal use of Undefer_Abortion
- -- to reduce overhead due to multiple calls to Self.
-
- procedure Undefer_Abortion is
- Self_ID : constant Task_ID := STPO.Self;
-
- begin
- pragma Assert (Self_ID.Deferral_Level > 0);
-
- Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1;
-
- if Self_ID.Deferral_Level = 0 then
- pragma Assert (Check_No_Locks (Self_ID));
-
- if Self_ID.Pending_Action then
- Do_Pending_Action (Self_ID);
- end if;
- end if;
- end Undefer_Abortion;
-
- ----------------------
- -- Update_Exception --
- ----------------------
-
- -- Call only when holding no locks.
-
- procedure Update_Exception
- (X : AE.Exception_Occurrence := Current_Target_Exception)
- is
- Self_Id : constant Task_ID := Self;
- use Ada.Exceptions;
-
- begin
- Save_Occurrence (Self_Id.Common.Compiler_Data.Current_Excep, X);
-
- if Self_Id.Deferral_Level = 0 then
- if Self_Id.Pending_Action then
- Self_Id.Pending_Action := False;
- Self_Id.Deferral_Level := Self_Id.Deferral_Level + 1;
- Write_Lock (Self_Id);
- Self_Id.Pending_Action := False;
- Poll_Base_Priority_Change (Self_Id);
- Unlock (Self_Id);
- Self_Id.Deferral_Level := Self_Id.Deferral_Level - 1;
-
- if Self_Id.Pending_ATC_Level < Self_Id.ATC_Nesting_Level then
- if not Self_Id.Aborting then
- Self_Id.Aborting := True;
- raise Standard'Abort_Signal;
- end if;
- end if;
- end if;
- end if;
- end Update_Exception;
-
- --------------------------
- -- Wakeup_Entry_Caller --
- --------------------------
-
- -- This is called at the end of service of an entry call, to abort the
- -- caller if he is in an abortable part, and to wake up the caller if it
- -- is on Entry_Caller_Sleep. It assumes that the call is already off-queue.
-
- -- (This enforces the rule that a task must be off-queue if its state is
- -- Done or Cancelled.) Call it holding the lock of Entry_Call.Self.
-
- -- Timed_Call or Simple_Call:
- -- The caller is waiting on Entry_Caller_Sleep, in
- -- Wait_For_Completion, or Wait_For_Completion_With_Timeout.
-
- -- Conditional_Call:
- -- The caller might be in Wait_For_Completion,
- -- waiting for a rendezvous (possibly requeued without abort)
- -- to complete.
-
- -- Asynchronous_Call:
- -- The caller may be executing in the abortable part o
- -- an async. select, or on a time delay,
- -- if Entry_Call.State >= Was_Abortable.
-
- procedure Wakeup_Entry_Caller
- (Self_ID : Task_ID;
- Entry_Call : Entry_Call_Link;
- New_State : Entry_Call_State)
- is
- Caller : constant Task_ID := Entry_Call.Self;
-
- begin
- pragma Debug (Debug.Trace
- (Self_ID, "Wakeup_Entry_Caller", Caller, 'E'));
- pragma Assert (New_State = Done or else New_State = Cancelled);
-
- pragma Assert
- (Caller.Common.State /= Terminated
- and then Caller.Common.State /= Unactivated);
-
- Entry_Call.State := New_State;
-
- if Entry_Call.Mode = Asynchronous_Call then
-
- -- Abort the caller in his abortable part,
- -- but do so only if call has been queued abortably
-
- if Entry_Call.State >= Was_Abortable or else New_State = Done then
- Locked_Abort_To_Level (Self_ID, Caller, Entry_Call.Level - 1);
- end if;
-
- elsif Caller.Common.State = Entry_Caller_Sleep then
- Wakeup (Caller, Entry_Caller_Sleep);
- end if;
- end Wakeup_Entry_Caller;
-
- ----------------------
- -- Soft-Link Bodies --
- ----------------------
-
- function Get_Current_Excep return SSL.EOA is
- Me : constant Task_ID := STPO.Self;
-
- begin
- return Me.Common.Compiler_Data.Current_Excep'Access;
- end Get_Current_Excep;
-
- function Get_Exc_Stack_Addr return Address is
- Me : constant Task_ID := STPO.Self;
-
- begin
- return Me.Common.Compiler_Data.Exc_Stack_Addr;
- end Get_Exc_Stack_Addr;
-
- function Get_Jmpbuf_Address return Address is
- Me : constant Task_ID := STPO.Self;
-
- begin
- return Me.Common.Compiler_Data.Jmpbuf_Address;
- end Get_Jmpbuf_Address;
-
- function Get_Machine_State_Addr return Address is
- Me : constant Task_ID := STPO.Self;
-
- begin
- return Me.Common.Compiler_Data.Machine_State_Addr;
- end Get_Machine_State_Addr;
-
- function Get_Sec_Stack_Addr return Address is
- Me : constant Task_ID := STPO.Self;
-
- begin
- return Me.Common.Compiler_Data.Sec_Stack_Addr;
- end Get_Sec_Stack_Addr;
-
- function Get_Stack_Info return Stack_Checking.Stack_Access is
- Me : constant Task_ID := STPO.Self;
-
- begin
- return Me.Common.Compiler_Data.Pri_Stack_Info'Access;
- end Get_Stack_Info;
-
- procedure Set_Exc_Stack_Addr (Self_ID : Address; Addr : Address) is
- Me : Task_ID := To_Task_Id (Self_ID);
-
- begin
- if Me = Null_Task then
- Me := STPO.Self;
- end if;
-
- Me.Common.Compiler_Data.Exc_Stack_Addr := Addr;
- end Set_Exc_Stack_Addr;
-
- procedure Set_Jmpbuf_Address (Addr : Address) is
- Me : Task_ID := STPO.Self;
-
- begin
- Me.Common.Compiler_Data.Jmpbuf_Address := Addr;
- end Set_Jmpbuf_Address;
-
- procedure Set_Machine_State_Addr (Addr : Address) is
- Me : Task_ID := STPO.Self;
-
- begin
- Me.Common.Compiler_Data.Machine_State_Addr := Addr;
- end Set_Machine_State_Addr;
-
- procedure Set_Sec_Stack_Addr (Addr : Address) is
- Me : Task_ID := STPO.Self;
-
- begin
- Me.Common.Compiler_Data.Sec_Stack_Addr := Addr;
- end Set_Sec_Stack_Addr;
-
- procedure Timed_Delay_T (Time : Duration; Mode : Integer) is
- Self_ID : constant Task_ID := Self;
-
- begin
- STPO.Timed_Delay (Self_ID, Time, Mode);
- end Timed_Delay_T;
-
- ------------------------
- -- Soft-Link Dummies --
- ------------------------
-
- -- These are dummies for subprograms that are only needed by certain
- -- optional run-time system packages. If they are needed, the soft
- -- links will be redirected to the real subprogram by elaboration of
- -- the subprogram body where the real subprogram is declared.
-
- procedure Finalize_Attributes (T : Task_ID) is
- begin
- null;
- end Finalize_Attributes;
-
- procedure Initialize_Attributes (T : Task_ID) is
- begin
- null;
- end Initialize_Attributes;
-
-begin
- Init_RTS;
-end System.Tasking.Initialization;
projects / msp430-gcc.git / blobdiff