1------------------------------------------------------------------------------
2--                                                                          --
3--                GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS               --
4--                                                                          --
5--           S Y S T E M . I N T E R R U P T _ M A N A G E M E N T          --
6--                                                                          --
7--                                  B o d y                                 --
8--                                                                          --
9--          Copyright (C) 1992-2004 Free Software Foundation, Inc.          --
10--                                                                          --
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,  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-- GNARL was developed by the GNARL team at Florida State University.       --
30-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
31--                                                                          --
32------------------------------------------------------------------------------
33
34--  This is the VxWorks version of this package.
35
36--  It is likely to need tailoring to fit each operating system
37--  and machine architecture.
38
39--  PLEASE DO NOT add any dependences on other packages.
40--  This package is designed to work with or without tasking support.
41
42--  See the other warnings in the package specification before making
43--  any modifications to this file.
44
45--  Make a careful study of all signals available under the OS,
46--  to see which need to be reserved, kept always unmasked,
47--  or kept always unmasked.
48--  Be on the lookout for special signals that
49--  may be used by the thread library.
50
51with Interfaces.C;
52
53with System.OS_Interface;
54--  used for various Constants, Signal and types
55
56package body System.Interrupt_Management is
57
58   use System.OS_Interface;
59   use type Interfaces.C.int;
60
61   type Signal_List is array (Signal_ID range <>) of Signal_ID;
62   Exception_Signals : constant Signal_List (1 .. 4) :=
63                         (SIGFPE, SIGILL, SIGSEGV, SIGBUS);
64
65   --  Keep these variables global so that they are initialized only once
66   --  What are "these variables" ???, I see only one
67
68   Exception_Action : aliased struct_sigaction;
69
70   procedure Map_And_Raise_Exception (signo : Signal);
71   pragma Import (C, Map_And_Raise_Exception, "__gnat_map_signal");
72   --  Map signal to Ada exception and raise it.  Different versions
73   --  of VxWorks need different mappings.
74
75   -----------------------
76   -- Local Subprograms --
77   -----------------------
78
79   procedure Notify_Exception (signo : Signal);
80   --  Identify the Ada exception to be raised using
81   --  the information when the system received a synchronous signal.
82
83   ----------------------
84   -- Notify_Exception --
85   ----------------------
86
87   procedure Notify_Exception (signo : Signal) is
88      Mask   : aliased sigset_t;
89      My_Id  : t_id;
90
91      Result : int;
92      pragma Unreferenced (Result);
93
94   begin
95      Result := pthread_sigmask (SIG_SETMASK, null, Mask'Unchecked_Access);
96      Result := sigdelset (Mask'Access, signo);
97      Result := pthread_sigmask (SIG_SETMASK, Mask'Unchecked_Access, null);
98
99      --  VxWorks will suspend the task when it gets a hardware
100      --  exception.  We take the liberty of resuming the task
101      --  for the application.
102
103      My_Id := taskIdSelf;
104
105      if taskIsSuspended (My_Id) /= 0 then
106         Result := taskResume (My_Id);
107      end if;
108
109      Map_And_Raise_Exception (signo);
110   end Notify_Exception;
111
112   ---------------------------
113   -- Initialize_Interrupts --
114   ---------------------------
115
116   --  Since there is no signal inheritance between VxWorks tasks, we need
117   --  to initialize signal handling in each task.
118
119   procedure Initialize_Interrupts is
120      Result  : int;
121      old_act : aliased struct_sigaction;
122
123   begin
124      for J in Exception_Signals'Range loop
125         Result :=
126           sigaction
127             (Signal (Exception_Signals (J)), Exception_Action'Access,
128              old_act'Unchecked_Access);
129         pragma Assert (Result = 0);
130      end loop;
131   end Initialize_Interrupts;
132
133begin
134   declare
135      mask   : aliased sigset_t;
136      Result : int;
137
138      function State (Int : Interrupt_ID) return Character;
139      pragma Import (C, State, "__gnat_get_interrupt_state");
140      --  Get interrupt state.  Defined in a-init.c
141      --  The input argument is the interrupt number,
142      --  and the result is one of the following:
143
144      Runtime : constant Character := 'r';
145      Default : constant Character := 's';
146      --    'n'   this interrupt not set by any Interrupt_State pragma
147      --    'u'   Interrupt_State pragma set state to User
148      --    'r'   Interrupt_State pragma set state to Runtime
149      --    's'   Interrupt_State pragma set state to System (use "default"
150      --           system handler)
151
152   begin
153      --  Initialize signal handling
154
155      --  Change this if you want to use another signal for task abort.
156      --  SIGTERM might be a good one.
157
158      Abort_Task_Signal := SIGABRT;
159
160      Exception_Action.sa_handler := Notify_Exception'Address;
161      Exception_Action.sa_flags := SA_ONSTACK;
162      Result := sigemptyset (mask'Access);
163      pragma Assert (Result = 0);
164
165      for J in Exception_Signals'Range loop
166         Result := sigaddset (mask'Access, Signal (Exception_Signals (J)));
167         pragma Assert (Result = 0);
168      end loop;
169
170      Exception_Action.sa_mask := mask;
171
172      --  Initialize hardware interrupt handling
173
174      pragma Assert (Reserve = (Interrupt_ID'Range => False));
175
176      --  Check all interrupts for state that requires keeping them reserved
177
178      for J in Interrupt_ID'Range loop
179         if State (J) = Default or else State (J) = Runtime then
180            Reserve (J) := True;
181         end if;
182      end loop;
183
184      --  Add exception signals to the set of unmasked signals
185
186      for J in Exception_Signals'Range loop
187         Keep_Unmasked (Exception_Signals (J)) := True;
188      end loop;
189
190      --  The abort signal must also be unmasked
191
192      Keep_Unmasked (Abort_Task_Signal) := True;
193   end;
194end System.Interrupt_Management;
195