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------------------------------------------------------------------------------

--                                                                          --

--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --

--                                                                          --

--                     S Y S T E M . I N T E R R U P T S                    --

--                                                                          --

--                                  B o d y                                 --

--                                                                          --

--          Copyright (C) 1998-2009, 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.     --

--                                                                          --

------------------------------------------------------------------------------

--  This is the IRIX & NT version of this package

with Ada.Task_Identification;

with Ada.Unchecked_Conversion;

with Interfaces.C;

with System.Storage_Elements;

with System.Task_Primitives.Operations;

with System.Tasking.Utilities;

with System.Tasking.Rendezvous;

with System.Tasking.Initialization;

with System.Interrupt_Management;

with System.Parameters;

package body System.Interrupts is

   use Parameters;

   use Tasking;

   use System.OS_Interface;

   use Interfaces.C;

   package STPO renames System.Task_Primitives.Operations;

   package IMNG renames System.Interrupt_Management;

   subtype int is Interfaces.C.int;

   function To_System is new Ada.Unchecked_Conversion

     (Ada.Task_Identification.Task_Id, Task_Id);

   type Handler_Kind is (Unknown, Task_Entry, Protected_Procedure);

   type Handler_Desc is record

      Kind   : Handler_Kind := Unknown;

      T      : Task_Id;

      E      : Task_Entry_Index;

      H      : Parameterless_Handler;

      Static : Boolean := False;

   end record;

   task type Server_Task (Interrupt : Interrupt_ID) is

      pragma Interrupt_Priority (System.Interrupt_Priority'Last);

   end Server_Task;

   type Server_Task_Access is access Server_Task;

   Handlers        : array (Interrupt_ID) of Task_Id;

   Descriptors     : array (Interrupt_ID) of Handler_Desc;

   Interrupt_Count : array (Interrupt_ID) of Integer := (others => 0);

   pragma Volatile_Components (Interrupt_Count);

   procedure Attach_Handler

     (New_Handler : Parameterless_Handler;

      Interrupt   : Interrupt_ID;

      Static      : Boolean;

      Restoration : Boolean);

   --  This internal procedure is needed to finalize protected objects

   --  that contain interrupt handlers.

   procedure Signal_Handler (Sig : Interrupt_ID);

   pragma Convention (C, Signal_Handler);

   --  This procedure is used to handle all the signals

   --  Type and Head, Tail of the list containing Registered Interrupt

   --  Handlers. These definitions are used to register the handlers

   --  specified by the pragma Interrupt_Handler.

   --------------------------

   -- Handler Registration --

   --------------------------

   type Registered_Handler;

   type R_Link is access all Registered_Handler;

   type Registered_Handler is record

      H    : System.Address := System.Null_Address;

      Next : R_Link := null;

   end record;

   Registered_Handlers : R_Link := null;

   function Is_Registered (Handler : Parameterless_Handler) return Boolean;

   --  See if the Handler has been "pragma"ed using Interrupt_Handler.

   --  Always consider a null handler as registered.

   type Handler_Ptr is access procedure (Sig : Interrupt_ID);

   pragma Convention (C, Handler_Ptr);

   function TISR is new Ada.Unchecked_Conversion (Handler_Ptr, isr_address);

   --------------------

   -- Signal_Handler --

   --------------------

   procedure Signal_Handler (Sig : Interrupt_ID) is

      Handler : Task_Id renames Handlers (Sig);

   begin

      if Intr_Attach_Reset and then

        intr_attach (int (Sig), TISR (Signal_Handler'Access)) = FUNC_ERR

      then

         raise Program_Error;

      end if;

      if Handler /= null then

         Interrupt_Count (Sig) := Interrupt_Count (Sig) + 1;

         STPO.Wakeup (Handler, Interrupt_Server_Idle_Sleep);

      end if;

   end Signal_Handler;

   -----------------

   -- Is_Reserved --

   -----------------

   function Is_Reserved (Interrupt : Interrupt_ID) return Boolean is

   begin

      return IMNG.Reserve (IMNG.Interrupt_ID (Interrupt));

   end Is_Reserved;

   -----------------------

   -- Is_Entry_Attached --

   -----------------------

   function Is_Entry_Attached (Interrupt : Interrupt_ID) return Boolean is

   begin

      if Is_Reserved (Interrupt) then

         raise Program_Error with

           "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved";

      end if;

      return Descriptors (Interrupt).T /= Null_Task;

   end Is_Entry_Attached;

   -------------------------

   -- Is_Handler_Attached --

   -------------------------

   function Is_Handler_Attached (Interrupt : Interrupt_ID) return Boolean is

   begin

      if Is_Reserved (Interrupt) then

         raise Program_Error with

           "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved";

      else

         return Descriptors (Interrupt).Kind /= Unknown;

      end if;

   end Is_Handler_Attached;

   ----------------

   -- Is_Ignored --

   ----------------

   function Is_Ignored (Interrupt : Interrupt_ID) return Boolean is

   begin

      raise Program_Error;

      return False;

   end Is_Ignored;

   ------------------

   -- Unblocked_By --

   ------------------

   function Unblocked_By (Interrupt : Interrupt_ID) return Task_Id is

   begin

      raise Program_Error;

      return Null_Task;

   end Unblocked_By;

   ----------------------

   -- Ignore_Interrupt --

   ----------------------

   procedure Ignore_Interrupt (Interrupt : Interrupt_ID) is

   begin

      raise Program_Error;

   end Ignore_Interrupt;

   ------------------------

   -- Unignore_Interrupt --

   ------------------------

   procedure Unignore_Interrupt (Interrupt : Interrupt_ID) is

   begin

      raise Program_Error;

   end Unignore_Interrupt;

   -------------------------------------

   -- Has_Interrupt_Or_Attach_Handler --

   -------------------------------------

   function Has_Interrupt_Or_Attach_Handler

     (Object : access Dynamic_Interrupt_Protection) return Boolean

   is

      pragma Unreferenced (Object);

   begin

      return True;

   end Has_Interrupt_Or_Attach_Handler;

   --------------

   -- Finalize --

   --------------

   procedure Finalize (Object : in out Static_Interrupt_Protection) is

   begin

      --  ??? loop to be executed only when we're not doing library level

      --  finalization, since in this case all interrupt tasks are gone.

      for N in reverse Object.Previous_Handlers'Range loop

         Attach_Handler

           (New_Handler => Object.Previous_Handlers (N).Handler,

            Interrupt   => Object.Previous_Handlers (N).Interrupt,

            Static      => Object.Previous_Handlers (N).Static,

            Restoration => True);

      end loop;

      Tasking.Protected_Objects.Entries.Finalize

        (Tasking.Protected_Objects.Entries.Protection_Entries (Object));

   end Finalize;

   -------------------------------------

   -- Has_Interrupt_Or_Attach_Handler --

   -------------------------------------

   function Has_Interrupt_Or_Attach_Handler

     (Object : access Static_Interrupt_Protection) return Boolean

   is

      pragma Unreferenced (Object);

   begin

      return True;

   end Has_Interrupt_Or_Attach_Handler;

   ----------------------

   -- Install_Handlers --

   ----------------------

   procedure Install_Handlers

     (Object       : access Static_Interrupt_Protection;

      New_Handlers : New_Handler_Array)

   is

   begin

      for N in New_Handlers'Range loop

         --  We need a lock around this ???

         Object.Previous_Handlers (N).Interrupt := New_Handlers (N).Interrupt;

         Object.Previous_Handlers (N).Static    := Descriptors

           (New_Handlers (N).Interrupt).Static;

         --  We call Exchange_Handler and not directly Interrupt_Manager.

         --  Exchange_Handler so we get the Is_Reserved check.

         Exchange_Handler

           (Old_Handler => Object.Previous_Handlers (N).Handler,

            New_Handler => New_Handlers (N).Handler,

            Interrupt   => New_Handlers (N).Interrupt,

            Static      => True);

      end loop;

   end Install_Handlers;

   ---------------------------------

   -- Install_Restricted_Handlers --

   ---------------------------------

   procedure Install_Restricted_Handlers (Handlers : New_Handler_Array) is

   begin

      for N in Handlers'Range loop

         Attach_Handler (Handlers (N).Handler, Handlers (N).Interrupt, True);

      end loop;

   end Install_Restricted_Handlers;

   ---------------------

   -- Current_Handler --

   ---------------------

   function Current_Handler

     (Interrupt : Interrupt_ID) return Parameterless_Handler

   is

   begin

      if Is_Reserved (Interrupt) then

         raise Program_Error;

      end if;

      if Descriptors (Interrupt).Kind = Protected_Procedure then

         return Descriptors (Interrupt).H;

      else

         return null;

      end if;

   end Current_Handler;

   --------------------

   -- Attach_Handler --

   --------------------

   procedure Attach_Handler

     (New_Handler : Parameterless_Handler;

      Interrupt   : Interrupt_ID;

      Static      : Boolean := False) is

   begin

      Attach_Handler (New_Handler, Interrupt, Static, False);

   end Attach_Handler;

   procedure Attach_Handler

     (New_Handler : Parameterless_Handler;

      Interrupt   : Interrupt_ID;

      Static      : Boolean;

      Restoration : Boolean)

   is

      New_Task : Server_Task_Access;

   begin

      if Is_Reserved (Interrupt) then

         raise Program_Error;

      end if;

      if not Restoration and then not Static

         --  Tries to overwrite a static Interrupt Handler with dynamic handle

        and then

          (Descriptors (Interrupt).Static

            --  New handler not specified as an Interrupt Handler by a pragma

             or else not Is_Registered (New_Handler))

      then

         raise Program_Error with

           "Trying to overwrite a static Interrupt Handler with a " &

           "dynamic Handler";

      end if;

      if Handlers (Interrupt) = null then

         New_Task := new Server_Task (Interrupt);

         Handlers (Interrupt) := To_System (New_Task.all'Identity);

      end if;

      if intr_attach (int (Interrupt),

        TISR (Signal_Handler'Access)) = FUNC_ERR

      then

         raise Program_Error;

      end if;

      if New_Handler = null then

         --  The null handler means we are detaching the handler

         Descriptors (Interrupt) :=

           (Kind => Unknown, T => null, E => 0, H => null, Static => False);

      else

         Descriptors (Interrupt).Kind := Protected_Procedure;

         Descriptors (Interrupt).H := New_Handler;

         Descriptors (Interrupt).Static := Static;

      end if;

   end Attach_Handler;

   ----------------------

   -- Exchange_Handler --

   ----------------------

   procedure Exchange_Handler

     (Old_Handler : out Parameterless_Handler;

      New_Handler : Parameterless_Handler;

      Interrupt   : Interrupt_ID;

      Static      : Boolean := False)

   is

   begin

      if Is_Reserved (Interrupt) then

         raise Program_Error;

      end if;

      if Descriptors (Interrupt).Kind = Task_Entry then

         --  In case we have an Interrupt Entry already installed.

         --  raise a program error. (propagate it to the caller).

         raise Program_Error with "An interrupt is already installed";

      else

         Old_Handler := Current_Handler (Interrupt);

         Attach_Handler (New_Handler, Interrupt, Static);

      end if;

   end Exchange_Handler;

   --------------------

   -- Detach_Handler --

   --------------------

   procedure Detach_Handler

     (Interrupt : Interrupt_ID;

      Static    : Boolean := False)

   is

   begin

      if Is_Reserved (Interrupt) then

         raise Program_Error;

      end if;

      if Descriptors (Interrupt).Kind = Task_Entry then

         raise Program_Error with "Trying to detach an Interrupt Entry";

      end if;

      if not Static and then Descriptors (Interrupt).Static then

         raise Program_Error with

           "Trying to detach a static Interrupt Handler";

      end if;

      Descriptors (Interrupt) :=

        (Kind => Unknown, T => null, E => 0, H => null, Static => False);

      if intr_attach (int (Interrupt), null) = FUNC_ERR then

         raise Program_Error;

      end if;

   end Detach_Handler;

   ---------------

   -- Reference --

   ---------------

   function Reference (Interrupt : Interrupt_ID) return System.Address is

      Signal : constant System.Address :=

                 System.Storage_Elements.To_Address

                   (System.Storage_Elements.Integer_Address (Interrupt));

   begin

      if Is_Reserved (Interrupt) then

         --  Only usable Interrupts can be used for binding it to an Entry

         raise Program_Error;

      end if;

      return Signal;

   end Reference;

   --------------------------------

   -- Register_Interrupt_Handler --

   --------------------------------

   procedure Register_Interrupt_Handler (Handler_Addr : System.Address) is

   begin

      Registered_Handlers :=

       new Registered_Handler'(H => Handler_Addr, Next => Registered_Handlers);

   end Register_Interrupt_Handler;

   -------------------

   -- Is_Registered --

   -------------------

   --  See if the Handler has been "pragma"ed using Interrupt_Handler.

   --  Always consider a null handler as registered.

   function Is_Registered (Handler : Parameterless_Handler) return Boolean is

      Ptr : R_Link := Registered_Handlers;

      type Fat_Ptr is record

         Object_Addr  : System.Address;

         Handler_Addr : System.Address;

      end record;

      function To_Fat_Ptr is new Ada.Unchecked_Conversion

        (Parameterless_Handler, Fat_Ptr);

      Fat : Fat_Ptr;

   begin

      if Handler = null then

         return True;

      end if;

      Fat := To_Fat_Ptr (Handler);

      while Ptr /= null loop

         if Ptr.H = Fat.Handler_Addr then

            return True;

         end if;

         Ptr := Ptr.Next;

      end loop;

      return False;

   end Is_Registered;

   -----------------------------

   -- Bind_Interrupt_To_Entry --

   -----------------------------

   procedure Bind_Interrupt_To_Entry

     (T       : Task_Id;

      E       : Task_Entry_Index;

      Int_Ref : System.Address)

   is

      Interrupt   : constant Interrupt_ID :=

                      Interrupt_ID (Storage_Elements.To_Integer (Int_Ref));

      New_Task : Server_Task_Access;

   begin

      if Is_Reserved (Interrupt) then

         raise Program_Error;

      end if;

      if Descriptors (Interrupt).Kind /= Unknown then

         raise Program_Error with

           "A binding for this interrupt is already present";

      end if;

      if Handlers (Interrupt) = null then

         New_Task := new Server_Task (Interrupt);

         Handlers (Interrupt) := To_System (New_Task.all'Identity);

      end if;

      if intr_attach (int (Interrupt),

        TISR (Signal_Handler'Access)) = FUNC_ERR

      then

         raise Program_Error;

      end if;

      Descriptors (Interrupt).Kind := Task_Entry;

      Descriptors (Interrupt).T := T;

      Descriptors (Interrupt).E := E;

      --  Indicate the attachment of Interrupt Entry in ATCB. This is needed so

      --  that when an Interrupt Entry task terminates the binding can be

      --  cleaned up. The call to unbinding must be make by the task before it

      --  terminates.

      T.Interrupt_Entry := True;

   end Bind_Interrupt_To_Entry;

   ------------------------------

   -- Detach_Interrupt_Entries --

   ------------------------------

   procedure Detach_Interrupt_Entries (T : Task_Id) is

   begin

      for J in Interrupt_ID loop

         if not Is_Reserved (J) then

            if Descriptors (J).Kind = Task_Entry

              and then Descriptors (J).T = T

            then

               Descriptors (J).Kind := Unknown;

               if intr_attach (int (J), null) = FUNC_ERR then

                  raise Program_Error;

               end if;

            end if;

         end if;

      end loop;

      --  Indicate in ATCB that no Interrupt Entries are attached

      T.Interrupt_Entry := True;

   end Detach_Interrupt_Entries;

   ---------------------

   -- Block_Interrupt --

   ---------------------

   procedure Block_Interrupt (Interrupt : Interrupt_ID) is

   begin

      raise Program_Error;

   end Block_Interrupt;

   -----------------------

   -- Unblock_Interrupt --

   -----------------------

   procedure Unblock_Interrupt (Interrupt : Interrupt_ID) is

   begin

      raise Program_Error;

   end Unblock_Interrupt;

   ----------------

   -- Is_Blocked --

   ----------------

   function Is_Blocked (Interrupt : Interrupt_ID) return Boolean is

   begin

      raise Program_Error;

      return False;

   end Is_Blocked;

   task body Server_Task is

      Desc    : Handler_Desc renames Descriptors (Interrupt);

      Self_Id : constant Task_Id := STPO.Self;

      Temp    : Parameterless_Handler;

   begin

      Utilities.Make_Independent;

      loop

         while Interrupt_Count (Interrupt) > 0 loop

            Interrupt_Count (Interrupt) := Interrupt_Count (Interrupt) - 1;

            begin

               case Desc.Kind is

                  when Unknown =>

                     null;

                  when Task_Entry =>

                     Rendezvous.Call_Simple (Desc.T, Desc.E, Null_Address);

                  when Protected_Procedure =>

                     Temp := Desc.H;

                     Temp.all;

               end case;

            exception

               when others => null;

            end;

         end loop;

         Initialization.Defer_Abort (Self_Id);

         if Single_Lock then

            STPO.Lock_RTS;

         end if;

         STPO.Write_Lock (Self_Id);

         Self_Id.Common.State := Interrupt_Server_Idle_Sleep;

         STPO.Sleep (Self_Id, Interrupt_Server_Idle_Sleep);

         Self_Id.Common.State := Runnable;

         STPO.Unlock (Self_Id);

         if Single_Lock then

            STPO.Unlock_RTS;

         end if;

         Initialization.Undefer_Abort (Self_Id);

         --  Undefer abort here to allow a window for this task to be aborted

         --  at the time of system shutdown.

      end loop;

   end Server_Task;

end System.Interrupts;