gcc/ada/5zthrini.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --        S Y S T E M . T H R E A D S . I N I T I A L I Z A T I O N         --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2003 Free Software Foundation, Inc.          --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This is the VxWorks version of this package; to use this implementation,
  35 --  the task hook libraries should be included in the VxWorks kernel.
  36
  37 with System.Secondary_Stack;
  38 with Interfaces.C;
  39 with Unchecked_Conversion;
  40
  41 package body System.Threads.Initialization is
  42
  43    use Interfaces.C;
  44
  45    package SSS renames System.Secondary_Stack;
  46
  47    procedure Initialize_Task_Hooks;
  48    --  Register the appropriate hooks (Register and Reset_TSD) to the
  49    --  underlying OS, so that they will be called when a task is created
  50    --  or reset.
  51
  52    Current_ATSD : aliased System.Address;
  53    pragma Import (C, Current_ATSD, "__gnat_current_atsd");
  54
  55    ---------------------------
  56    -- Initialize_Task_Hooks --
  57    ---------------------------
  58
  59    procedure Initialize_Task_Hooks is separate;
  60    --  Separate, as these hooks are different for AE653 and VxWorks 5.5.
  61
  62    --------------
  63    -- Register --
  64    --------------
  65
  66    function Register (T : OSI.Thread_Id) return OSI.STATUS is
  67       TSD : ATSD_Access := new ATSD;
  68       Result : OSI.STATUS;
  69    begin
  70       --  It cannot be assumed that the caller of this routine has a ATSD;
  71       --  so neither this procedure nor the procedures that it calls should
  72       --  raise or handle exceptions,  or make use of a secondary stack.
  73
  74       if OSI.taskIdVerify (T) = OSI.ERROR
  75         or else OSI.taskVarGet (T, Current_ATSD'Access) /= OSI.ERROR
  76       then
  77          return OSI.ERROR;
  78       end if;
  79
  80       Result := OSI.taskVarAdd (T, Current_ATSD'Access);
  81       pragma Assert (Result /= -1);
  82       Result := OSI.taskVarSet (T, Current_ATSD'Access, TSD.all'Address);
  83       pragma Assert (Result /= -1);
  84       TSD.Sec_Stack_Addr := SSS.SS_Create;
  85       SSS.SS_Init (TSD.Sec_Stack_Addr);
  86       return Result;
  87    end Register;
  88
  89    ---------------
  90    -- Reset_TSD --
  91    ---------------
  92
  93    function Reset_TSD (T : OSI.Thread_Id) return OSI.STATUS is
  94       TSD_Ptr : int;
  95       function To_Address is new Unchecked_Conversion
  96         (Interfaces.C.int, ATSD_Access);
  97    begin
  98       TSD_Ptr := OSI.taskVarGet (T, Current_ATSD'Access);
  99       pragma Assert (TSD_Ptr /= OSI.ERROR);
 100
 101       --  Just reset the secondary stack pointer.  The implementation here
 102       --  assumes that the fixed secondary stack implementation is used.
 103       --  If not, there will be a memory leak (along with allocation, which
 104       --  is prohibited for ARINC processes once the system enters "normal"
 105       --  mode).
 106
 107       SSS.SS_Init (To_Address (TSD_Ptr).Sec_Stack_Addr);
 108       return OSI.OK;
 109    end Reset_TSD;
 110
 111 begin
 112    Initialize_Task_Hooks;
 113 end System.Threads.Initialization;