920 lines
32 KiB
Ada
920 lines
32 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
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-- --
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-- 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 --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2005, Free Software Foundation, Inc. --
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-- --
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-- GNARL is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNARL; see file COPYING. If not, write --
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-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
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-- Boston, MA 02110-1301, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- GNARL was developed by the GNARL team at Florida State University. --
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-- Extensive contributions were provided by Ada Core Technologies, Inc. --
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-- --
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------------------------------------------------------------------------------
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pragma Style_Checks (All_Checks);
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-- Turn off subprogram alpha ordering check, since we group soft link
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-- bodies and dummy soft link bodies together separately in this unit.
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pragma Polling (Off);
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-- Turn polling off for this package. We don't need polling during any
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-- of the routines in this package, and more to the point, if we try
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-- to poll it can cause infinite loops.
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with Ada.Exceptions;
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-- Used for Exception_Occurrence_Access
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with System.Task_Primitives;
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-- Used for Lock
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with System.Task_Primitives.Operations;
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-- Used for Set_Priority
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-- Write_Lock
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-- Unlock
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-- Initialize_Lock
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with System.Soft_Links;
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-- Used for the non-tasking routines (*_NT) that refer to global data.
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-- They are needed here before the tasking run time has been elaborated.
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with System.Soft_Links.Tasking;
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-- Used for Init_Tasking_Soft_Links
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with System.Tasking.Debug;
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-- Used for Trace
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with System.Stack_Checking;
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with System.Parameters;
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-- used for Single_Lock
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package body System.Tasking.Initialization is
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package STPO renames System.Task_Primitives.Operations;
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package SSL renames System.Soft_Links;
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package AE renames Ada.Exceptions;
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use Parameters;
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use Task_Primitives.Operations;
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Global_Task_Lock : aliased System.Task_Primitives.RTS_Lock;
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-- This is a global lock; it is used to execute in mutual exclusion
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-- from all other tasks. It is only used by Task_Lock,
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-- Task_Unlock, and Final_Task_Unlock.
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function Current_Target_Exception return AE.Exception_Occurrence;
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pragma Import
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(Ada, Current_Target_Exception, "__gnat_current_target_exception");
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-- Import this subprogram from the private part of Ada.Exceptions
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----------------------------------------------------------------------
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-- Tasking versions of some services needed by non-tasking programs --
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----------------------------------------------------------------------
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procedure Abort_Defer;
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-- NON-INLINE versions without Self_ID for soft links
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procedure Abort_Undefer;
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-- NON-INLINE versions without Self_ID for soft links
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procedure Task_Lock;
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-- Locks out other tasks. Preceding a section of code by Task_Lock and
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-- following it by Task_Unlock creates a critical region. This is used
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-- for ensuring that a region of non-tasking code (such as code used to
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-- allocate memory) is tasking safe. Note that it is valid for calls to
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-- Task_Lock/Task_Unlock to be nested, and this must work properly, i.e.
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-- only the corresponding outer level Task_Unlock will actually unlock.
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procedure Task_Unlock;
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-- Releases lock previously set by call to Task_Lock. In the nested case,
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-- all nested locks must be released before other tasks competing for the
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-- tasking lock are released.
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function Get_Stack_Info return Stack_Checking.Stack_Access;
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-- Get access to the current task's Stack_Info
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procedure Update_Exception
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(X : AE.Exception_Occurrence := Current_Target_Exception);
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-- Handle exception setting and check for pending actions
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function Task_Name return String;
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-- Returns current task's name
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------------------------
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-- Local Subprograms --
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------------------------
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----------------------------
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-- Tasking Initialization --
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----------------------------
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procedure Init_RTS;
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-- This procedure completes the initialization of the GNARL. The first
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-- part of the initialization is done in the body of System.Tasking.
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-- It consists of initializing global locks, and installing tasking
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-- versions of certain operations used by the compiler. Init_RTS is called
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-- during elaboration.
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--------------------------
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-- Change_Base_Priority --
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--------------------------
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-- Call only with abort deferred and holding Self_ID locked
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procedure Change_Base_Priority (T : Task_Id) is
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begin
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if T.Common.Base_Priority /= T.New_Base_Priority then
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T.Common.Base_Priority := T.New_Base_Priority;
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Set_Priority (T, T.Common.Base_Priority);
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end if;
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end Change_Base_Priority;
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------------------------
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-- Check_Abort_Status --
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------------------------
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function Check_Abort_Status return Integer is
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Self_ID : constant Task_Id := Self;
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begin
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if Self_ID /= null and then Self_ID.Deferral_Level = 0
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and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
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then
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return 1;
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else
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return 0;
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end if;
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end Check_Abort_Status;
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-----------------
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-- Defer_Abort --
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-----------------
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procedure Defer_Abort (Self_ID : Task_Id) is
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begin
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if No_Abort and then not Dynamic_Priority_Support then
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return;
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end if;
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pragma Assert (Self_ID.Deferral_Level = 0);
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-- pragma Assert
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-- (Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level);
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-- The above check has been useful in detecting mismatched defer/undefer
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-- pairs. You may uncomment it when testing on systems that support
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-- preemptive abort.
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-- If the OS supports preemptive abort (e.g. pthread_kill), it should
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-- have happened already. A problem is with systems that do not support
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-- preemptive abort, and so rely on polling. On such systems we may get
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-- false failures of the assertion, since polling for pending abort does
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-- no occur until the abort undefer operation.
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-- Even on systems that only poll for abort, the assertion may be useful
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-- for catching missed abort completion polling points. The operations
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-- that undefer abort poll for pending aborts. This covers most of the
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-- places where the core Ada semantics require abort to be caught,
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-- without any special attention. However, this generally happens on
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-- exit from runtime system call, which means a pending abort will not
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-- be noticed on the way into the runtime system. We considered adding a
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-- check for pending aborts at this point, but chose not to, because of
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-- the overhead. Instead, we searched for RTS calls where abort
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-- completion is required and a task could go farther than Ada allows
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-- before undeferring abort; we then modified the code to ensure the
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-- abort would be detected.
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Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
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end Defer_Abort;
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--------------------------
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-- Defer_Abort_Nestable --
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--------------------------
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procedure Defer_Abort_Nestable (Self_ID : Task_Id) is
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begin
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if No_Abort and then not Dynamic_Priority_Support then
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return;
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end if;
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-- pragma Assert
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-- ((Self_ID.Pending_ATC_Level >= Self_ID.ATC_Nesting_Level or else
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-- Self_ID.Deferral_Level > 0));
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-- See comment in Defer_Abort on the situations in which it may be
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-- useful to uncomment the above assertion.
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Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
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end Defer_Abort_Nestable;
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-----------------
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-- Abort_Defer --
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-----------------
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procedure Abort_Defer is
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Self_ID : Task_Id;
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begin
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if No_Abort and then not Dynamic_Priority_Support then
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return;
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end if;
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Self_ID := STPO.Self;
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Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
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end Abort_Defer;
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-----------------------
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-- Do_Pending_Action --
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-----------------------
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-- Call only when holding no locks
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procedure Do_Pending_Action (Self_ID : Task_Id) is
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use type Ada.Exceptions.Exception_Id;
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begin
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pragma Assert (Self_ID = Self and then Self_ID.Deferral_Level = 0);
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-- Needs loop to recheck for pending action in case a new one occurred
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-- while we had abort deferred below.
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loop
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-- Temporarily defer abort so that we can lock Self_ID
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Self_ID.Deferral_Level := Self_ID.Deferral_Level + 1;
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if Single_Lock then
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Lock_RTS;
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end if;
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Write_Lock (Self_ID);
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Self_ID.Pending_Action := False;
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Poll_Base_Priority_Change (Self_ID);
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Unlock (Self_ID);
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if Single_Lock then
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Unlock_RTS;
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end if;
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-- Restore the original Deferral value
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Self_ID.Deferral_Level := Self_ID.Deferral_Level - 1;
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if not Self_ID.Pending_Action then
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if Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level then
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if not Self_ID.Aborting then
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Self_ID.Aborting := True;
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pragma Debug
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(Debug.Trace (Self_ID, "raise Abort_Signal", 'B'));
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raise Standard'Abort_Signal;
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pragma Assert (not Self_ID.ATC_Hack);
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elsif Self_ID.ATC_Hack then
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-- The solution really belongs in the Abort_Signal handler
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-- for async. entry calls. The present hack is very
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-- fragile. It relies that the very next point after
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-- Exit_One_ATC_Level at which the task becomes abortable
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-- will be the call to Undefer_Abort in the
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-- Abort_Signal handler.
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Self_ID.ATC_Hack := False;
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pragma Debug
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(Debug.Trace
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(Self_ID, "raise Abort_Signal (ATC hack)", 'B'));
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raise Standard'Abort_Signal;
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end if;
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end if;
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return;
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end if;
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end loop;
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end Do_Pending_Action;
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-----------------------
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-- Final_Task_Unlock --
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-----------------------
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-- This version is only for use in Terminate_Task, when the task
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-- is relinquishing further rights to its own ATCB.
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-- There is a very interesting potential race condition there, where
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-- the old task may run concurrently with a new task that is allocated
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-- the old tasks (now reused) ATCB. The critical thing here is to
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-- not make any reference to the ATCB after the lock is released.
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-- See also comments on Terminate_Task and Unlock.
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procedure Final_Task_Unlock (Self_ID : Task_Id) is
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begin
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pragma Assert (Self_ID.Common.Global_Task_Lock_Nesting = 1);
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Unlock (Global_Task_Lock'Access, Global_Lock => True);
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end Final_Task_Unlock;
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--------------
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-- Init_RTS --
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--------------
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procedure Init_RTS is
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Self_Id : Task_Id;
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begin
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Tasking.Initialize;
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-- Terminate run time (regular vs restricted) specific initialization
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-- of the environment task.
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Self_Id := Environment_Task;
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Self_Id.Master_of_Task := Environment_Task_Level;
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Self_Id.Master_Within := Self_Id.Master_of_Task + 1;
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for L in Self_Id.Entry_Calls'Range loop
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Self_Id.Entry_Calls (L).Self := Self_Id;
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Self_Id.Entry_Calls (L).Level := L;
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end loop;
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Self_Id.Awake_Count := 1;
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Self_Id.Alive_Count := 1;
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Self_Id.Master_Within := Library_Task_Level;
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-- Normally, a task starts out with internal master nesting level
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-- one larger than external master nesting level. It is incremented
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-- to one by Enter_Master, which is called in the task body only if
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-- the compiler thinks the task may have dependent tasks. There is no
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-- corresponding call to Enter_Master for the environment task, so we
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-- would need to increment it to 2 here. Instead, we set it to 3.
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-- By doing this we reserve the level 2 for server tasks of the runtime
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-- system. The environment task does not need to wait for these server
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-- Initialize lock used to implement mutual exclusion between all tasks
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Initialize_Lock (Global_Task_Lock'Access, STPO.Global_Task_Level);
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-- Notify that the tasking run time has been elaborated so that
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-- the tasking version of the soft links can be used.
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if not No_Abort or else Dynamic_Priority_Support then
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SSL.Abort_Defer := Abort_Defer'Access;
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SSL.Abort_Undefer := Abort_Undefer'Access;
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end if;
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SSL.Update_Exception := Update_Exception'Access;
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SSL.Lock_Task := Task_Lock'Access;
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SSL.Unlock_Task := Task_Unlock'Access;
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SSL.Check_Abort_Status := Check_Abort_Status'Access;
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SSL.Get_Stack_Info := Get_Stack_Info'Access;
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SSL.Task_Name := Task_Name'Access;
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-- Initialize the tasking soft links (if not done yet) that are common
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-- to the full and the restricted run times.
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SSL.Tasking.Init_Tasking_Soft_Links;
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-- Abort is deferred in a new ATCB, so we need to undefer abort
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-- at this stage to make the environment task abortable.
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Undefer_Abort (Environment_Task);
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end Init_RTS;
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---------------------------
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-- Locked_Abort_To_Level--
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---------------------------
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-- Abort a task to the specified ATC nesting level.
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-- Call this only with T locked.
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-- An earlier version of this code contained a call to Wakeup. That
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-- should not be necessary here, if Abort_Task is implemented correctly,
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-- since Abort_Task should include the effect of Wakeup. However, the
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-- above call was in earlier versions of this file, and at least for
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-- some targets Abort_Task has not beek doing Wakeup. It should not
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-- hurt to uncomment the above call, until the error is corrected for
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-- all targets.
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-- See extended comments in package body System.Tasking.Abort for the
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-- overall design of the implementation of task abort.
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-- ??? there is no such package ???
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-- If the task is sleeping it will be in an abort-deferred region, and
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-- will not have Abort_Signal raised by Abort_Task. Such an "abort
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-- deferral" is just to protect the RTS internals, and not necessarily
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-- required to enforce Ada semantics. Abort_Task should wake the task up
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-- and let it decide if it wants to complete the aborted construct
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-- immediately.
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-- Note that the effect of the lowl-level Abort_Task is not persistent.
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-- If the target task is not blocked, this wakeup will be missed.
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-- We don't bother calling Abort_Task if this task is aborting itself,
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-- since we are inside the RTS and have abort deferred. Similarly, We
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-- don't bother to call Abort_Task if T is terminated, since there is
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-- no need to abort a terminated task, and it could be dangerous to try
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-- if the task has stopped executing.
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-- Note that an earlier version of this code had some false reasoning
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-- about being able to reliably wake up a task that had suspended on
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-- a blocking system call that does not atomically relase the task's
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-- lock (e.g., UNIX nanosleep, which we once thought could be used to
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-- implement delays). That still left the possibility of missed
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-- wakeups.
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-- We cannot safely call Vulnerable_Complete_Activation here, since that
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-- requires locking Self_ID.Parent. The anti-deadlock lock ordering rules
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-- would then require us to release the lock on Self_ID first, which would
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-- create a timing window for other tasks to lock Self_ID. This is
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-- significant for tasks that may be aborted before their execution can
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-- enter the task body, and so they do not get a chance to call
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-- Complete_Task. The actual work for this case is done in Terminate_Task.
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procedure Locked_Abort_To_Level
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(Self_ID : Task_Id;
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T : Task_Id;
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L : ATC_Level)
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is
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begin
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if not T.Aborting and then T /= Self_ID then
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case T.Common.State is
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when Unactivated | Terminated =>
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pragma Assert (False);
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null;
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when Runnable =>
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-- This is needed to cancel an asynchronous protected entry
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-- call during a requeue with abort.
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T.Entry_Calls
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(T.ATC_Nesting_Level).Cancellation_Attempted := True;
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when Interrupt_Server_Blocked_On_Event_Flag =>
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null;
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when Delay_Sleep |
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Async_Select_Sleep |
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Interrupt_Server_Idle_Sleep |
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Interrupt_Server_Blocked_Interrupt_Sleep |
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Timer_Server_Sleep |
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AST_Server_Sleep =>
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Wakeup (T, T.Common.State);
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when Acceptor_Sleep =>
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T.Open_Accepts := null;
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Wakeup (T, T.Common.State);
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when Entry_Caller_Sleep =>
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T.Entry_Calls
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(T.ATC_Nesting_Level).Cancellation_Attempted := True;
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Wakeup (T, T.Common.State);
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when Activator_Sleep |
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Master_Completion_Sleep |
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Master_Phase_2_Sleep |
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Asynchronous_Hold =>
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null;
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end case;
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end if;
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if T.Pending_ATC_Level > L then
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T.Pending_ATC_Level := L;
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T.Pending_Action := True;
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if L = 0 then
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T.Callable := False;
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end if;
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-- This prevents aborted task from accepting calls
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if T.Aborting then
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-- The test above is just a heuristic, to reduce wasteful
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-- calls to Abort_Task. We are holding T locked, and this
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-- value will not be set to False except with T also locked,
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-- inside Exit_One_ATC_Level, so we should not miss wakeups.
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if T.Common.State = Acceptor_Sleep then
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T.Open_Accepts := null;
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end if;
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elsif T /= Self_ID and then
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(T.Common.State = Runnable
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or else T.Common.State = Interrupt_Server_Blocked_On_Event_Flag)
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-- The task is blocked on a system call waiting for the
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-- completion event. In this case Abort_Task may need to take
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-- special action in order to succeed. Example system: VMS.
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|
|
|
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
|
|
if Single_Lock then
|
|
Unlock_RTS;
|
|
Yield;
|
|
Lock_RTS;
|
|
else
|
|
Unlock (Self_ID);
|
|
Yield;
|
|
Write_Lock (Self_ID);
|
|
end if;
|
|
|
|
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);
|
|
|
|
if Single_Lock then
|
|
Unlock_RTS;
|
|
Yield;
|
|
Lock_RTS;
|
|
else
|
|
Unlock (Self_ID);
|
|
Yield;
|
|
Write_Lock (Self_ID);
|
|
end if;
|
|
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 (Self, "Remove_From_All_Tasks_List", 'C'));
|
|
|
|
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;
|
|
|
|
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 (Self_ID : Task_Id) is
|
|
begin
|
|
Self_ID.Common.Global_Task_Lock_Nesting :=
|
|
Self_ID.Common.Global_Task_Lock_Nesting + 1;
|
|
|
|
if Self_ID.Common.Global_Task_Lock_Nesting = 1 then
|
|
Defer_Abort_Nestable (Self_ID);
|
|
Write_Lock (Global_Task_Lock'Access, Global_Lock => True);
|
|
end if;
|
|
end Task_Lock;
|
|
|
|
procedure Task_Lock is
|
|
begin
|
|
Task_Lock (STPO.Self);
|
|
end Task_Lock;
|
|
|
|
---------------
|
|
-- Task_Name --
|
|
---------------
|
|
|
|
function Task_Name return String is
|
|
Self_Id : constant Task_Id := STPO.Self;
|
|
|
|
begin
|
|
return Self_Id.Common.Task_Image (1 .. Self_Id.Common.Task_Image_Len);
|
|
end Task_Name;
|
|
|
|
-----------------
|
|
-- Task_Unlock --
|
|
-----------------
|
|
|
|
procedure Task_Unlock (Self_ID : Task_Id) is
|
|
begin
|
|
pragma Assert (Self_ID.Common.Global_Task_Lock_Nesting > 0);
|
|
Self_ID.Common.Global_Task_Lock_Nesting :=
|
|
Self_ID.Common.Global_Task_Lock_Nesting - 1;
|
|
|
|
if Self_ID.Common.Global_Task_Lock_Nesting = 0 then
|
|
Unlock (Global_Task_Lock'Access, Global_Lock => True);
|
|
Undefer_Abort_Nestable (Self_ID);
|
|
end if;
|
|
end Task_Unlock;
|
|
|
|
procedure Task_Unlock is
|
|
begin
|
|
Task_Unlock (STPO.Self);
|
|
end Task_Unlock;
|
|
|
|
-------------------
|
|
-- Undefer_Abort --
|
|
-------------------
|
|
|
|
-- Precondition : Self does not hold any locks!
|
|
|
|
-- Undefer_Abort is called on any abort completion point (aka.
|
|
-- synchronization point). It performs the following actions if they
|
|
-- are pending: (1) change the base priority, (2) abort the task.
|
|
|
|
-- The priority change has to occur before abort. Otherwise, it would
|
|
-- take effect no earlier than the next abort completion point.
|
|
|
|
procedure Undefer_Abort (Self_ID : Task_Id) is
|
|
begin
|
|
if No_Abort and then not Dynamic_Priority_Support then
|
|
return;
|
|
end if;
|
|
|
|
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
|
|
if No_Abort and then not Dynamic_Priority_Support then
|
|
return;
|
|
end if;
|
|
|
|
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;
|
|
|
|
-------------------
|
|
-- Abort_Undefer --
|
|
-------------------
|
|
|
|
procedure Abort_Undefer is
|
|
Self_ID : Task_Id;
|
|
begin
|
|
if No_Abort and then not Dynamic_Priority_Support then
|
|
return;
|
|
end if;
|
|
|
|
Self_ID := STPO.Self;
|
|
|
|
if Self_ID.Deferral_Level = 0 then
|
|
|
|
-- In case there are different views on whether Abort is supported
|
|
-- between the expander and the run time, we may end up with
|
|
-- Self_ID.Deferral_Level being equal to zero, when called from
|
|
-- the procedure created by the expander that corresponds to a
|
|
-- task body.
|
|
|
|
-- In this case, there's nothing to be done
|
|
|
|
-- See related code in System.Tasking.Stages.Create_Task resetting
|
|
-- Deferral_Level when System.Restrictions.Abort_Allowed is False.
|
|
|
|
return;
|
|
end if;
|
|
|
|
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 Abort_Undefer;
|
|
|
|
----------------------
|
|
-- 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;
|
|
|
|
if Single_Lock then
|
|
Lock_RTS;
|
|
end if;
|
|
|
|
Write_Lock (Self_Id);
|
|
Self_Id.Pending_Action := False;
|
|
Poll_Base_Priority_Change (Self_Id);
|
|
Unlock (Self_Id);
|
|
|
|
if Single_Lock then
|
|
Unlock_RTS;
|
|
end if;
|
|
|
|
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", 'E', Caller));
|
|
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_Stack_Info return Stack_Checking.Stack_Access is
|
|
begin
|
|
return STPO.Self.Common.Compiler_Data.Pri_Stack_Info'Access;
|
|
end Get_Stack_Info;
|
|
|
|
-----------------------
|
|
-- 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
|
|
pragma Warnings (Off, T);
|
|
|
|
begin
|
|
null;
|
|
end Finalize_Attributes;
|
|
|
|
procedure Initialize_Attributes (T : Task_Id) is
|
|
pragma Warnings (Off, T);
|
|
|
|
begin
|
|
null;
|
|
end Initialize_Attributes;
|
|
|
|
begin
|
|
Init_RTS;
|
|
end System.Tasking.Initialization;
|