summaryrefslogtreecommitdiff
path: root/gcc/ada/s-interr.ads
blob: e61f3ab9ec9a1d2cd5da772bfc6c6b7460d96d1e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
------------------------------------------------------------------------------
--                                                                          --
--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
--                                                                          --
--                     S Y S T E M . I N T E R R U P T S                    --
--                                                                          --
--                                  S p e c                                 --
--                                                                          --
--          Copyright (C) 1992-2014, 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.     --
--                                                                          --
------------------------------------------------------------------------------

--  Note: the compiler generates direct calls to this interface, via Rtsfind.
--  Any changes to this interface may require corresponding compiler changes.

--  This package encapsulates the implementation of interrupt or signal
--  handlers. It is logically an extension of the body of Ada.Interrupts. It
--  is made a child of System to allow visibility of various runtime system
--  internal data and operations.

--  See System.Interrupt_Management for core interrupt/signal interfaces

--  These two packages are separated to allow System.Interrupt_Management to be
--  used without requiring the whole tasking implementation to be linked and
--  elaborated.

with System.Tasking;
with System.Tasking.Protected_Objects.Entries;
with System.OS_Interface;

package System.Interrupts is

   pragma Elaborate_Body;
   --  Comment needed on why this is here ???

   -------------------------
   -- Constants and types --
   -------------------------

   Default_Interrupt_Priority : constant System.Interrupt_Priority :=
     System.Interrupt_Priority'Last;
   --  Default value used when a pragma Interrupt_Handler or Attach_Handler is
   --  specified without an Interrupt_Priority pragma, see D.3(10).

   type Ada_Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;
   --  Avoid inheritance by Ada.Interrupts.Interrupt_ID of unwanted operations

   type Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;

   subtype System_Interrupt_Id is Interrupt_ID;
   --  This synonym is introduced so that the type is accessible through
   --  rtsfind, otherwise the name clashes with its homonym in Ada.Interrupts.

   type Parameterless_Handler is access protected procedure;

   ----------------------
   -- General services --
   ----------------------

   --  Attempt to attach a Handler to an Interrupt to which an Entry is
   --  already bound will raise a Program_Error.

   function Is_Reserved (Interrupt : Interrupt_ID) return Boolean;

   function Is_Entry_Attached (Interrupt : Interrupt_ID) return Boolean;

   function Is_Handler_Attached (Interrupt : Interrupt_ID) return Boolean;

   function Current_Handler
     (Interrupt : Interrupt_ID) return Parameterless_Handler;

   --  Calling the following procedures with New_Handler = null and Static =
   --  true means that we want to modify the current handler regardless of the
   --  previous handler's binding status. (i.e. we do not care whether it is a
   --  dynamic or static handler)

   procedure Attach_Handler
     (New_Handler : Parameterless_Handler;
      Interrupt   : Interrupt_ID;
      Static      : Boolean := False);

   procedure Exchange_Handler
     (Old_Handler : out Parameterless_Handler;
      New_Handler : Parameterless_Handler;
      Interrupt   : Interrupt_ID;
      Static      : Boolean := False);

   procedure Detach_Handler
     (Interrupt : Interrupt_ID;
      Static    : Boolean := False);

   function Reference
     (Interrupt : Interrupt_ID) return System.Address;

   --------------------------------
   -- Interrupt Entries Services --
   --------------------------------

   --  Routines needed for Interrupt Entries

   procedure Bind_Interrupt_To_Entry
     (T       : System.Tasking.Task_Id;
      E       : System.Tasking.Task_Entry_Index;
      Int_Ref : System.Address);
   --  Bind the given interrupt to the given entry. If the interrupt is
   --  already bound to another entry, Program_Error will be raised.

   procedure Detach_Interrupt_Entries (T : System.Tasking.Task_Id);
   --  This procedure detaches all the Interrupt Entries bound to a task

   ------------------------------
   -- POSIX.5 Signals Services --
   ------------------------------

   --  Routines needed for POSIX dot5 POSIX_Signals

   procedure Block_Interrupt (Interrupt : Interrupt_ID);
   --  Block the Interrupt on the process level

   procedure Unblock_Interrupt (Interrupt : Interrupt_ID);

   function Unblocked_By
     (Interrupt : Interrupt_ID) return System.Tasking.Task_Id;
   --  It returns the ID of the last Task which Unblocked this Interrupt.
   --  It returns Null_Task if no tasks have ever requested the Unblocking
   --  operation or the Interrupt is currently Blocked.

   function Is_Blocked (Interrupt : Interrupt_ID) return Boolean;
   --  Comment needed ???

   procedure Ignore_Interrupt (Interrupt : Interrupt_ID);
   --  Set the sigaction for the interrupt to SIG_IGN

   procedure Unignore_Interrupt (Interrupt : Interrupt_ID);
   --  Comment needed ???

   function Is_Ignored (Interrupt : Interrupt_ID) return Boolean;
   --  Comment needed ???

   --  Note : Direct calls to sigaction, sigprocmask, thr_sigsetmask, or any
   --  other low-level interface that changes the signal action or signal mask
   --  needs careful thought.

   --  One may achieve the effect of system calls first making RTS blocked (by
   --  calling Block_Interrupt) for the signal under consideration. This will
   --  make all the tasks in RTS blocked for the Interrupt.

   ----------------------
   -- Protection Types --
   ----------------------

   --  Routines and types needed to implement Interrupt_Handler and
   --  Attach_Handler.

   --  There are two kinds of protected objects that deal with interrupts:

   --  (1) Only Interrupt_Handler pragmas are used. We need to be able to tell
   --  if an Interrupt_Handler applies to a given procedure, so
   --  Register_Interrupt_Handler has to be called for all the potential
   --  handlers, it should be done by calling Register_Interrupt_Handler with
   --  the handler code address. On finalization, which can happen only has
   --  part of library level finalization since PO with Interrupt_Handler
   --  pragmas can only be declared at library level, nothing special needs to
   --  be done since the default handlers have been restored as part of task
   --  completion which is done just before global finalization.
   --  Dynamic_Interrupt_Protection should be used in this case.

   --  (2) Attach_Handler pragmas are used, and possibly Interrupt_Handler
   --  pragma. We need to attach the handlers to the given interrupts when the
   --  object is elaborated. This should be done by constructing an array of
   --  pairs (interrupt, handler) from the pragmas and calling Install_Handlers
   --  with it (types to be used are New_Handler_Item and New_Handler_Array).
   --  On finalization, we need to restore the handlers that were installed
   --  before the elaboration of the PO, so we need to store these previous
   --  handlers. This is also done by Install_Handlers, the room for this
   --  information is provided by adding a discriminant which is the number
   --  of Attach_Handler pragmas and an array of this size in the protection
   --  type, Static_Interrupt_Protection.

   procedure Register_Interrupt_Handler
     (Handler_Addr : System.Address);
   --  This routine should be called by the compiler to allow the handler be
   --  used as an Interrupt Handler. That means call this procedure for each
   --  pragma Interrupt_Handler providing the address of the handler (not
   --  including the pointer to the actual PO, this way this routine is called
   --  only once for each type definition of PO).

   type Static_Handler_Index is range 0 .. Integer'Last;
   subtype Positive_Static_Handler_Index is
     Static_Handler_Index range 1 .. Static_Handler_Index'Last;
   --  Comment needed ???

   type Previous_Handler_Item is record
      Interrupt : Interrupt_ID;
      Handler   : Parameterless_Handler;
      Static    : Boolean;
   end record;
   --  Contains all the information needed to restore a previous handler

   type Previous_Handler_Array is array
     (Positive_Static_Handler_Index range <>) of Previous_Handler_Item;

   type New_Handler_Item is record
      Interrupt : Interrupt_ID;
      Handler   : Parameterless_Handler;
   end record;
   --  Contains all the information from an Attach_Handler pragma

   type New_Handler_Array is
     array (Positive_Static_Handler_Index range <>) of New_Handler_Item;
   --  Comment needed ???

   --  Case (1)

   type Dynamic_Interrupt_Protection is new
     Tasking.Protected_Objects.Entries.Protection_Entries with null record;

   --  ??? Finalize is not overloaded since we currently have no
   --  way to detach the handlers during library level finalization.

   function Has_Interrupt_Or_Attach_Handler
     (Object : access Dynamic_Interrupt_Protection) return Boolean;
   --  Returns True

   --  Case (2)

   type Static_Interrupt_Protection
     (Num_Entries        : Tasking.Protected_Objects.Protected_Entry_Index;
      Num_Attach_Handler : Static_Handler_Index)
   is new
     Tasking.Protected_Objects.Entries.Protection_Entries (Num_Entries) with
     record
       Previous_Handlers : Previous_Handler_Array (1 .. Num_Attach_Handler);
     end record;

   function Has_Interrupt_Or_Attach_Handler
     (Object : access Static_Interrupt_Protection) return Boolean;
   --  Returns True

   overriding procedure Finalize (Object : in out Static_Interrupt_Protection);
   --  Restore previous handlers as required by C.3.1(12) then call
   --  Finalize (Protection).

   procedure Install_Handlers
     (Object       : access Static_Interrupt_Protection;
      New_Handlers : New_Handler_Array);
   --  Store the old handlers in Object.Previous_Handlers and install
   --  the new static handlers.

   procedure Install_Restricted_Handlers
     (Prio     : Any_Priority;
      Handlers : New_Handler_Array);
   --  Install the static Handlers for the given interrupts and do not
   --  store previously installed handlers. This procedure is used when
   --  the Ravenscar restrictions are in place since in that case there
   --  are only library-level protected handlers that will be installed
   --  at initialization and never be replaced.

end System.Interrupts;