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205 | ------------------------------------------------------------------------------
-- --
-- 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) 2001-2023, AdaCore --
-- --
-- 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. 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. --
-- --
-- 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. --
-- --
------------------------------------------------------------------------------
-- This is the Ravenscar/HI-E and Ravenscar/full version of this package
pragma Restrictions (No_Elaboration_Code);
-- For Ravenscar/HI-E, this restriction is simply an optimization.
-- For Ravenscar/full, this restriction is required because the Initialize
-- procedure is called by s-init before the elaboration.
with System.Task_Primitives.Operations;
package body System.Tasking is
use System.Multiprocessors;
use System.Secondary_Stack;
------------------------
-- Local Declarations --
------------------------
Main_Priority : Integer := Unspecified_Priority;
pragma Export (C, Main_Priority, "__gl_main_priority");
-- Priority associated with the environment task. By default, its value is
-- undefined, and can be set by using pragma Priority in the main program.
Main_CPU : Integer := Unspecified_CPU;
pragma Export (C, Main_CPU, "__gl_main_cpu");
-- Affinity associated with the environment task. By default, its value is
-- undefined, and can be set by using pragma CPU in the main program.
-- Switching the environment task to the right CPU is left to the user.
Environment_Task : aliased Ada_Task_Control_Block (Entry_Num => 0);
-- ATCB for the environment task. The name of this array is
-- 'Environment_Task', so that there is a nice display of the environment
-- task in GDB (which uses the suffix of the symbol).
-------------------
-- Get_Sec_Stack --
-------------------
function Get_Sec_Stack return SS_Stack_Ptr is
begin
return Self.Common.Compiler_Data.Sec_Stack_Ptr;
end Get_Sec_Stack;
---------------------
-- Initialize_ATCB --
---------------------
procedure Initialize_ATCB
(Task_Entry_Point : Task_Procedure_Access;
Task_Arg : System.Address;
Base_Priority : Extended_Priority;
Base_CPU : System.Multiprocessors.CPU_Range;
Task_Info : System.Task_Info.Task_Info_Type;
Stack_Address : System.Address;
Stack_Size : System.Parameters.Size_Type;
T : Task_Id;
Success : out Boolean)
is
begin
T.Common.State := Unactivated;
-- Initialize T.Common.LL
Task_Primitives.Operations.Initialize_TCB (T, Success);
if not Success then
return;
end if;
T.Common.Base_Priority := Base_Priority;
T.Common.Base_CPU := Base_CPU;
T.Common.Protected_Action_Nesting := 0;
T.Common.Task_Arg := Task_Arg;
T.Common.Task_Entry_Point := Task_Entry_Point;
T.Common.Task_Info := Task_Info;
T.Common.Compiler_Data.Pri_Stack_Info.Start_Address :=
Stack_Address;
T.Common.Compiler_Data.Pri_Stack_Info.Size :=
Storage_Elements.Storage_Offset
(Parameters.Adjust_Storage_Size (Stack_Size));
end Initialize_ATCB;
----------------
-- Initialize --
----------------
Initialized : Boolean := False;
-- Used to prevent multiple calls to Initialize
procedure Initialize is
Base_Priority : Any_Priority;
Success : Boolean;
pragma Warnings (Off, Success);
begin
if Initialized then
return;
end if;
Initialized := True;
-- Compute priority
if Main_Priority = Unspecified_Priority then
Base_Priority := Default_Priority;
else
Base_Priority := Main_Priority;
end if;
Initialize_ATCB
(null, Null_Address, Base_Priority, CPU'First,
Task_Info.Unspecified_Task_Info, Null_Address, 0,
Environment_Task'Access, Success);
Task_Primitives.Operations.Initialize
(Environment_Task'Access);
-- Note: we used to set the priority at this point, but it is already
-- done in Enter_Task via s-taprop.Initialize.
Environment_Task.Common.State := Runnable;
Environment_Task.Entry_Call.Self := Environment_Task'Access;
-- Set the environment secondary stack pointer to null to allow SS_Init
-- to assign a stack from the default-sized secondary stack pool.
Environment_Task.Common.Compiler_Data.Sec_Stack_Ptr := null;
SS_Init
(Environment_Task.Common.Compiler_Data.Sec_Stack_Ptr);
-- No fall back handler by default
Fall_Back_Handler := null;
-- Legal values of CPU are the special Unspecified_CPU value, which is
-- inserted by the compiler for tasks without CPU aspect, and those in
-- the range of CPU_Range but no greater than Number_Of_CPUs. Otherwise
-- the task is defined to have failed, and it becomes a completed task
-- (RM D.16(14/3)).
-- Only accept CPU'First for CPU value, starting on a slave CPU is not
-- supported.
if Main_CPU /= Unspecified_CPU and then Main_CPU /= Integer (CPU'First)
then
-- Invalid CPU, will raise Tasking_Error after the environment task
-- is initialized (as exception propagation is supported in the full
-- Ravenscar profile).
raise Tasking_Error with "Main CPU is not the master one";
end if;
end Initialize;
----------
-- Self --
----------
function Self return Task_Id renames System.Task_Primitives.Operations.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;
end System.Tasking;
|