------------------------------------------------------------------------------ -- -- -- 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) 1992-2019, 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 -- -- . -- -- -- -- GNARL was developed by the GNARL team at Florida State University. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ pragma Polling (Off); -- Turn off polling, we do not want ATC polling to take place during tasking -- operations. It causes infinite loops and other problems. with System.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 := 0; 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 : 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 : 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;