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274 | ------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . T A S K I N G --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2023, 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 3, or (at your option) any later ver- --
-- sion. GNAT 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. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. --
-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
------------------------------------------------------------------------------
with System.Task_Primitives.Operations;
with System.Storage_Elements;
package body System.Tasking is
package STPO renames System.Task_Primitives.Operations;
---------------------
-- Detect_Blocking --
---------------------
function Detect_Blocking return Boolean is
GL_Detect_Blocking : Integer;
pragma Import (C, GL_Detect_Blocking, "__gl_detect_blocking");
-- Global variable exported by the binder generated file. A value equal
-- to 1 indicates that pragma Detect_Blocking is active, while 0 is used
-- for the pragma not being present.
begin
return GL_Detect_Blocking = 1;
end Detect_Blocking;
-----------------------
-- Number_Of_Entries --
-----------------------
function Number_Of_Entries (Self_Id : Task_Id) return Entry_Index is
begin
return Entry_Index (Self_Id.Entry_Num);
end Number_Of_Entries;
----------
-- Self --
----------
function Self return Task_Id renames STPO.Self;
------------------
-- Storage_Size --
------------------
function Storage_Size (T : Task_Id) return System.Parameters.Size_Type is
begin
return
System.Parameters.Size_Type
(T.Common.Compiler_Data.Pri_Stack_Info.Size);
end Storage_Size;
---------------------
-- Initialize_ATCB --
---------------------
procedure Initialize_ATCB
(Self_ID : Task_Id;
Task_Entry_Point : Task_Procedure_Access;
Task_Arg : System.Address;
Parent : Task_Id;
Elaborated : Access_Boolean;
Base_Priority : System.Any_Priority;
Base_CPU : System.Multiprocessors.CPU_Range;
Domain : Dispatching_Domain_Access;
Task_Info : System.Task_Info.Task_Info_Type;
Stack_Size : System.Parameters.Size_Type;
T : Task_Id;
Success : out Boolean)
is
begin
T.Common.State := Unactivated;
-- Initialize T.Common.LL
STPO.Initialize_TCB (T, Success);
if not Success then
return;
end if;
-- Note that use of an aggregate here for this assignment
-- would be illegal, because Common_ATCB is limited because
-- Task_Primitives.Private_Data is limited.
T.Common.Parent := Parent;
T.Common.Base_Priority := Base_Priority;
T.Common.Base_CPU := Base_CPU;
-- The Domain defaults to that of the activator. But that can be null in
-- the case of foreign threads (see Register_Foreign_Thread), in which
-- case we default to the System_Domain.
if Domain /= null then
T.Common.Domain := Domain;
elsif Self_ID.Common.Domain /= null then
T.Common.Domain := Self_ID.Common.Domain;
else
T.Common.Domain := System_Domain;
end if;
pragma Assert (T.Common.Domain /= null);
T.Common.Current_Priority := Priority'First;
T.Common.Protected_Action_Nesting := 0;
T.Common.Call := null;
T.Common.Task_Arg := Task_Arg;
T.Common.Task_Entry_Point := Task_Entry_Point;
T.Common.Activator := Self_ID;
T.Common.Wait_Count := 0;
T.Common.Elaborated := Elaborated;
T.Common.Activation_Failed := False;
T.Common.Task_Info := Task_Info;
T.Common.Global_Task_Lock_Nesting := 0;
T.Common.Fall_Back_Handler := null;
T.Common.Specific_Handler := null;
T.Common.Debug_Events := [others => False];
T.Common.Task_Image_Len := 0;
if T.Common.Parent = null then
-- For the environment task, the adjusted stack size is meaningless.
-- For example, an unspecified Stack_Size means that the stack size
-- is determined by the environment, or can grow dynamically. The
-- Stack_Checking algorithm therefore needs to use the requested
-- size, or 0 in case of an unknown size.
T.Common.Compiler_Data.Pri_Stack_Info.Size :=
Storage_Elements.Storage_Offset (Stack_Size);
else
T.Common.Compiler_Data.Pri_Stack_Info.Size :=
Storage_Elements.Storage_Offset
(Parameters.Adjust_Storage_Size (Stack_Size));
end if;
-- Link the task into the list of all tasks
T.Common.All_Tasks_Link := All_Tasks_List;
All_Tasks_List := T;
end Initialize_ATCB;
----------------
-- Initialize --
----------------
Main_Task_Image : constant String := "main_task";
-- Image of environment task
Main_Priority : constant Integer;
pragma Import (C, Main_Priority, "__gl_main_priority");
-- Priority for main task. Note that this is of type Integer, not Priority,
-- because we use the value -1 to indicate the default main priority, and
-- that is of course not in Priority'range.
Main_CPU : constant Integer;
pragma Import (C, Main_CPU, "__gl_main_cpu");
-- Affinity for main task. Note that this is of type Integer, not
-- CPU_Range, because we use the value -1 to indicate the unassigned
-- affinity, and that is of course not in CPU_Range'Range.
Initialized : Boolean := False;
-- Used to prevent multiple calls to Initialize
procedure Initialize is
T : Task_Id;
Base_Priority : Any_Priority;
Base_CPU : System.Multiprocessors.CPU_Range;
Success : Boolean;
use type System.Multiprocessors.CPU_Range;
begin
if Initialized then
return;
end if;
Initialized := True;
-- Initialize Environment Task
Base_Priority :=
(if Main_Priority = Unspecified_Priority
then Default_Priority
else Priority (Main_Priority));
Base_CPU :=
(if Main_CPU = Unspecified_CPU
then System.Multiprocessors.Not_A_Specific_CPU
else System.Multiprocessors.CPU_Range (Main_CPU));
-- At program start-up the environment task is allocated to the default
-- system dispatching domain.
-- Make sure that the processors which are not available are not taken
-- into account. Use Number_Of_CPUs to know the exact number of
-- processors in the system at execution time.
System_Domain :=
new Dispatching_Domain'
(Multiprocessors.CPU'First .. Multiprocessors.Number_Of_CPUs =>
True);
T := STPO.New_ATCB (0);
Initialize_ATCB
(Self_ID => null,
Task_Entry_Point => null,
Task_Arg => Null_Address,
Parent => Null_Task,
Elaborated => null,
Base_Priority => Base_Priority,
Base_CPU => Base_CPU,
Domain => System_Domain,
Task_Info => Task_Info.Unspecified_Task_Info,
Stack_Size => 0,
T => T,
Success => Success);
pragma Assert (Success);
STPO.Initialize (T);
STPO.Set_Priority (T, T.Common.Base_Priority);
T.Common.State := Runnable;
T.Common.Task_Image_Len := Main_Task_Image'Length;
T.Common.Task_Image (Main_Task_Image'Range) := Main_Task_Image;
Dispatching_Domain_Tasks :=
new Array_Allocated_Tasks'
(Multiprocessors.CPU'First .. Multiprocessors.Number_Of_CPUs => 0);
-- Signal that this task is being allocated to a processor
if Base_CPU /= System.Multiprocessors.Not_A_Specific_CPU then
-- Increase the number of tasks attached to the CPU to which this
-- task is allocated.
Dispatching_Domain_Tasks (Base_CPU) :=
Dispatching_Domain_Tasks (Base_CPU) + 1;
end if;
-- The full initialization of the environment task's Entry_Calls array
-- is deferred to Init_RTS because only the first element of the array
-- is used by the restricted Ravenscar runtime.
T.Entry_Calls (T.Entry_Calls'First).Self := T;
T.Entry_Calls (T.Entry_Calls'First).Level := T.Entry_Calls'First;
end Initialize;
end System.Tasking;
|