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) 1999-2006 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 2, or (at your option) any later ver- --
14 -- sion. GNARL 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 GNARL; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
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. --
29 -- GNARL was developed by the GNARL team at Florida State University. --
30 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
32 ------------------------------------------------------------------------------
34 -- This is the VxWorks version of this package.
35 -- This file should be kept synchronized with the general implementation
36 -- provided by s-stchop.adb.
38 pragma Restrictions (No_Elaboration_Code);
39 -- We want to guarantee the absence of elaboration code because the
40 -- binder does not handle references to this package.
44 with System.Storage_Elements; use System.Storage_Elements;
45 with System.Parameters; use System.Parameters;
46 with System.Soft_Links;
48 with System.OS_Interface;
50 package body System.Stack_Checking.Operations is
52 -- In order to have stack checking working appropriately on
53 -- VxWorks we need to extract the stack size information from the
54 -- VxWorks kernel itself. It means that the library for showing
55 -- task-related information needs to be linked into the VxWorks
56 -- system, when using stack checking. The TaskShow library can be
57 -- linked into the VxWorks system by either:
58 -- * defining INCLUDE_SHOW_ROUTINES in config.h when using
59 -- configuration header files, or
60 -- * selecting INCLUDE_TASK_SHOW when using the Tornado project
63 function Set_Stack_Info (Stack : access Stack_Access) return Stack_Access;
65 -- The function Set_Stack_Info is the actual function that updates
66 -- the cache containing a pointer to the Stack_Info. It may also
67 -- be used for detecting asynchronous abort in combination with
68 -- Invalidate_Self_Cache.
70 -- Set_Stack_Info should do the following things in order:
71 -- 1) Get the Stack_Access value for the current task
72 -- 2) Set Stack.all to the value obtained in 1)
73 -- 3) Optionally Poll to check for asynchronous abort
75 -- This order is important because if at any time a write to
76 -- the stack cache is pending, that write should be followed
77 -- by a Poll to prevent loosing signals.
79 -- Note: This function must be compiled with Polling turned off
81 -- Note: on systems like VxWorks and OS/2 with real thread-local storage,
82 -- Set_Stack_Info should return an access value for such local
83 -- storage. In those cases the cache will always be up-to-date.
85 -- The following constants should be imported from some system-specific
86 -- constants package. The constants must be static for performance reasons.
88 ----------------------------
89 -- Invalidate_Stack_Cache --
90 ----------------------------
92 procedure Invalidate_Stack_Cache (Any_Stack : Stack_Access) is
93 pragma Warnings (Off, Any_Stack);
96 end Invalidate_Stack_Cache;
102 function Set_Stack_Info
103 (Stack : access Stack_Access) return Stack_Access
106 -- Task descriptor that is handled internally by the VxWorks kernel
108 type Td_Events_Storage is array (1 .. 4) of Interfaces.C.int;
109 pragma Convention (C, Td_Events_Storage);
111 type Task_Descriptor is record
112 T_Id : Interfaces.C.int; -- task identifier
113 Td_Name : System.Address; -- task name
114 Td_Priority : Interfaces.C.int; -- task priority
115 Td_Status : Interfaces.C.int; -- task status
116 Td_Options : Interfaces.C.int; -- task option bits (see below)
117 Td_Entry : System.Address; -- original entry point of task
118 Td_Sp : System.Address; -- saved stack pointer
119 Td_PStackBase : System.Address; -- the bottom of the stack
120 Td_PStackLimit : System.Address; -- the effective end of the stack
121 Td_PStackEnd : System.Address; -- the actual end of the stack
122 Td_StackSize : Interfaces.C.int; -- size of stack in bytes
123 Td_StackCurrent : Interfaces.C.int; -- current stack usage in bytes
124 Td_StackHigh : Interfaces.C.int; -- maximum stack usage in bytes
125 Td_StackMargin : Interfaces.C.int; -- current stack margin in bytes
126 Td_ErrorStatus : Interfaces.C.int; -- most recent task error status
127 Td_Delay : Interfaces.C.int; -- delay/timeout ticks
128 Td_Events : Td_Events_Storage; -- task events, post t2.0
130 pragma Convention (C, Task_Descriptor);
132 -- This VxWorks procedure fills in a specified task descriptor
133 -- for a specified task.
134 procedure TaskInfoGet (T_Id : System.OS_Interface.t_id;
135 Task_Desc : access Task_Descriptor);
136 pragma Import (C, TaskInfoGet, "taskInfoGet");
138 My_Stack : Stack_Access;
139 Task_Desc : aliased Task_Descriptor;
142 -- The order of steps 1 .. 3 is important, see specification.
144 -- 1) Get the Stack_Access value for the current task
146 My_Stack := Soft_Links.Get_Stack_Info.all;
148 if My_Stack.Base = Null_Address then
150 -- First invocation. Ask the VxWorks kernel about stack
152 TaskInfoGet (System.OS_Interface.taskIdSelf, Task_Desc'Access);
154 My_Stack.Size := System.Storage_Elements.Storage_Offset
155 (Task_Desc.Td_StackSize);
156 My_Stack.Base := Task_Desc.Td_PStackBase;
157 My_Stack.Limit := Task_Desc.Td_PStackLimit;
161 -- 2) Set Stack.all to the value obtained in 1)
163 Stack.all := My_Stack;
165 -- 3) Optionally Poll to check for asynchronous abort
167 if Soft_Links.Check_Abort_Status.all /= 0 then
168 raise Standard'Abort_Signal;
171 return My_Stack; -- Never trust the cached value, but return local copy!
179 (Stack_Address : System.Address) return Stack_Access
181 type Frame_Marker is null record;
182 Marker : Frame_Marker;
183 Cached_Stack : constant Stack_Access := Cache;
184 Frame_Address : constant System.Address := Marker'Address;
187 -- This function first does a "cheap" check which is correct
188 -- if it succeeds. In case of failure, the full check is done.
189 -- Ideally the cheap check should be done in an optimized manner,
192 if (Stack_Grows_Down and then
193 (Frame_Address <= Cached_Stack.Base
195 Stack_Address > Cached_Stack.Limit))
197 (not Stack_Grows_Down and then
198 (Frame_Address >= Cached_Stack.Base
200 Stack_Address < Cached_Stack.Limit))
202 -- Cached_Stack is valid as it passed the stack check
208 My_Stack : constant Stack_Access := Set_Stack_Info (Cache'Access);
209 -- At this point Stack.all might already be invalid, so
210 -- it is essential to use our local copy of Stack!
213 if (Stack_Grows_Down and then
214 Stack_Address < My_Stack.Limit)
216 (not Stack_Grows_Down and then
217 Stack_Address > My_Stack.Limit)
219 Ada.Exceptions.Raise_Exception
220 (E => Storage_Error'Identity,
221 Message => "stack overflow detected");
228 ------------------------
229 -- Update_Stack_Cache --
230 ------------------------
232 procedure Update_Stack_Cache (Stack : Stack_Access) is
234 if not Multi_Processor then
237 end Update_Stack_Cache;
239 end System.Stack_Checking.Operations;