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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . S T A C K _ C H E C K I N G . O P E R A T I O N S --
-- --
-- B o d y --
-- --
-- Copyright (C) 1999-2009, 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 verson for VxWorks 5 and VxWorks MILS
-- This file should be kept synchronized with the general implementation
-- provided by s-stchop.adb.
pragma Restrictions (No_Elaboration_Code);
-- We want to guarantee the absence of elaboration code because the
-- binder does not handle references to this package.
with System.Storage_Elements; use System.Storage_Elements;
with System.Parameters; use System.Parameters;
with Interfaces.C;
package body System.Stack_Checking.Operations is
-- In order to have stack checking working appropriately on VxWorks we need
-- to extract the stack size information from the VxWorks kernel itself.
-- For VxWorks 5 the library for showing task-related information needs to
-- be linked into the VxWorks system, when using stack checking. The
-- taskShow library can be linked into the VxWorks system by either:
-- * defining INCLUDE_SHOW_ROUTINES in config.h when using
-- configuration header files, or
-- * selecting INCLUDE_TASK_SHOW when using the Tornado project
-- facility.
-- VxWorks MILS includes the necessary routine in taskLib, so nothing
-- special needs to be done there.
Stack_Limit : Address :=
Boolean'Pos (Stack_Grows_Down) * Address'First
+ Boolean'Pos (not Stack_Grows_Down) * Address'Last;
pragma Export (C, Stack_Limit, "__gnat_stack_limit");
-- Stack_Limit contains the limit of the stack. This variable is later made
-- a task variable (by calling taskVarAdd) and then correctly set to the
-- stack limit of the task. Before being so initialized its value must be
-- valid so that any subprogram with stack checking enabled will run. We
-- use extreme values according to the direction of the stack.
type Set_Stack_Limit_Proc_Acc is access procedure;
pragma Convention (C, Set_Stack_Limit_Proc_Acc);
Set_Stack_Limit_Hook : Set_Stack_Limit_Proc_Acc;
pragma Import (C, Set_Stack_Limit_Hook, "__gnat_set_stack_limit_hook");
-- Procedure to be called when a task is created to set stack
-- limit.
procedure Set_Stack_Limit_For_Current_Task;
pragma Convention (C, Set_Stack_Limit_For_Current_Task);
-- Register Initial_SP as the initial stack pointer value for the current
-- task when it starts and Size as the associated stack area size. This
-- should be called once, after the soft-links have been initialized?
-----------------------------
-- Initialize_Stack_Limit --
-----------------------------
procedure Initialize_Stack_Limit is
begin
-- For the environment task
Set_Stack_Limit_For_Current_Task;
-- Will be called by every created task
Set_Stack_Limit_Hook := Set_Stack_Limit_For_Current_Task'Access;
end Initialize_Stack_Limit;
--------------------------------------
-- Set_Stack_Limit_For_Current_Task --
--------------------------------------
procedure Set_Stack_Limit_For_Current_Task is
use Interfaces.C;
function Task_Var_Add (Tid : Interfaces.C.int; Var : Address)
return Interfaces.C.int;
pragma Import (C, Task_Var_Add, "taskVarAdd");
-- Import from VxWorks
type OS_Stack_Info is record
Size : Interfaces.C.int;
Base : System.Address;
Limit : System.Address;
end record;
pragma Convention (C, OS_Stack_Info);
-- Type representing the information that we want to extract from the
-- underlying kernel.
procedure Get_Stack_Info (Stack : not null access OS_Stack_Info);
pragma Import (C, Get_Stack_Info, "__gnat_get_stack_info");
-- Procedure that fills the stack information associated to the
-- currently executing task.
Stack_Info : aliased OS_Stack_Info;
Limit : System.Address;
begin
-- Get stack bounds from VxWorks
Get_Stack_Info (Stack_Info'Access);
-- In s-stchop.adb, we check for overflow in the following operations,
-- but we have no such check in this vxworks version. Why not ???
if Stack_Grows_Down then
Limit := Stack_Info.Base - Storage_Offset (Stack_Info.Size);
else
Limit := Stack_Info.Base + Storage_Offset (Stack_Info.Size);
end if;
-- Note: taskVarAdd implicitly calls taskVarInit if required
if Task_Var_Add (0, Stack_Limit'Address) = 0 then
Stack_Limit := Limit;
end if;
end Set_Stack_Limit_For_Current_Task;
end System.Stack_Checking.Operations;
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