1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- 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 --
9 -- Copyright (C) 1999-2009, Free Software Foundation, Inc. --
11 -- GNARL 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 3, 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. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNARL was developed by the GNARL team at Florida State University. --
28 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
30 ------------------------------------------------------------------------------
32 -- This is the VxWorks version of this package.
33 -- This file should be kept synchronized with the general implementation
34 -- provided by s-stchop.adb. This version is for VxWorks 5 and VxWorks MILS.
36 pragma Restrictions (No_Elaboration_Code);
37 -- We want to guarantee the absence of elaboration code because the
38 -- binder does not handle references to this package.
40 with System.Storage_Elements; use System.Storage_Elements;
41 with System.Parameters; use System.Parameters;
44 package body System.Stack_Checking.Operations is
46 -- In order to have stack checking working appropriately on VxWorks we need
47 -- to extract the stack size information from the VxWorks kernel itself.
49 -- For VxWorks 5 the library for showing task-related information needs to
50 -- be linked into the VxWorks system, when using stack checking. The
51 -- taskShow library can be linked into the VxWorks system by either:
53 -- * defining INCLUDE_SHOW_ROUTINES in config.h when using
54 -- configuration header files, or
56 -- * selecting INCLUDE_TASK_SHOW when using the Tornado project
59 -- VxWorks MILS includes the necessary routine in taskLib, so nothing
60 -- special needs to be done there.
62 Stack_Limit : Address :=
63 Boolean'Pos (Stack_Grows_Down) * Address'First
64 + Boolean'Pos (not Stack_Grows_Down) * Address'Last;
65 pragma Export (C, Stack_Limit, "__gnat_stack_limit");
66 -- Stack_Limit contains the limit of the stack. This variable is later made
67 -- a task variable (by calling taskVarAdd) and then correctly set to the
68 -- stack limit of the task. Before being so initialized its value must be
69 -- valid so that any subprogram with stack checking enabled will run. We
70 -- use extreme values according to the direction of the stack.
72 type Set_Stack_Limit_Proc_Acc is access procedure;
73 pragma Convention (C, Set_Stack_Limit_Proc_Acc);
75 Set_Stack_Limit_Hook : Set_Stack_Limit_Proc_Acc;
76 pragma Import (C, Set_Stack_Limit_Hook, "__gnat_set_stack_limit_hook");
77 -- Procedure to be called when a task is created to set stack
80 procedure Set_Stack_Limit_For_Current_Task;
81 pragma Convention (C, Set_Stack_Limit_For_Current_Task);
82 -- Register Initial_SP as the initial stack pointer value for the current
83 -- task when it starts and Size as the associated stack area size. This
84 -- should be called once, after the soft-links have been initialized?
86 -----------------------------
87 -- Initialize_Stack_Limit --
88 -----------------------------
90 procedure Initialize_Stack_Limit is
92 -- For the environment task
94 Set_Stack_Limit_For_Current_Task;
96 -- Will be called by every created task
98 Set_Stack_Limit_Hook := Set_Stack_Limit_For_Current_Task'Access;
99 end Initialize_Stack_Limit;
101 --------------------------------------
102 -- Set_Stack_Limit_For_Current_Task --
103 --------------------------------------
105 procedure Set_Stack_Limit_For_Current_Task is
108 function Task_Var_Add (Tid : Interfaces.C.int; Var : Address)
109 return Interfaces.C.int;
110 pragma Import (C, Task_Var_Add, "taskVarAdd");
111 -- Import from VxWorks
113 type OS_Stack_Info is record
114 Size : Interfaces.C.int;
115 Base : System.Address;
116 Limit : System.Address;
118 pragma Convention (C, OS_Stack_Info);
119 -- Type representing the information that we want to extract from the
120 -- underlying kernel.
122 procedure Get_Stack_Info (Stack : not null access OS_Stack_Info);
123 pragma Import (C, Get_Stack_Info, "__gnat_get_stack_info");
124 -- Procedure that fills the stack information associated to the
125 -- currently executing task.
127 Stack_Info : aliased OS_Stack_Info;
129 Limit : System.Address;
132 -- Get stack bounds from VxWorks
134 Get_Stack_Info (Stack_Info'Access);
136 -- In s-stchop.adb, we check for overflow in the following operations,
137 -- but we have no such check in this vxworks version. Why not ???
139 if Stack_Grows_Down then
140 Limit := Stack_Info.Base - Storage_Offset (Stack_Info.Size);
142 Limit := Stack_Info.Base + Storage_Offset (Stack_Info.Size);
145 -- Note: taskVarAdd implicitly calls taskVarInit if required
147 if Task_Var_Add (0, Stack_Limit'Address) = 0 then
148 Stack_Limit := Limit;
150 end Set_Stack_Limit_For_Current_Task;
152 end System.Stack_Checking.Operations;