File : s-interr.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
4 -- --
5 -- S Y S T E M . I N T E R R U P T S --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
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15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
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18 -- --
19 -- --
20 -- --
21 -- --
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/>. --
26 -- --
27 -- GNARL was developed by the GNARL team at Florida State University. --
28 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 -- Note: the compiler generates direct calls to this interface, via Rtsfind.
33 -- Any changes to this interface may require corresponding compiler changes.
34
35 -- This package encapsulates the implementation of interrupt or signal
36 -- handlers. It is logically an extension of the body of Ada.Interrupts. It
37 -- is made a child of System to allow visibility of various runtime system
38 -- internal data and operations.
39
40 -- See System.Interrupt_Management for core interrupt/signal interfaces
41
42 -- These two packages are separated to allow System.Interrupt_Management to be
43 -- used without requiring the whole tasking implementation to be linked and
44 -- elaborated.
45
46 with System.Tasking;
47 with System.Tasking.Protected_Objects.Entries;
48 with System.OS_Interface;
49
50 package System.Interrupts is
51
52 pragma Elaborate_Body;
53 -- Comment needed on why this is here ???
54
55 -------------------------
56 -- Constants and types --
57 -------------------------
58
59 Default_Interrupt_Priority : constant System.Interrupt_Priority :=
60 System.Interrupt_Priority'Last;
61 -- Default value used when a pragma Interrupt_Handler or Attach_Handler is
62 -- specified without an Interrupt_Priority pragma, see D.3(10).
63
64 type Ada_Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;
65 -- Avoid inheritance by Ada.Interrupts.Interrupt_ID of unwanted operations
66
67 type Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;
68
69 subtype System_Interrupt_Id is Interrupt_ID;
70 -- This synonym is introduced so that the type is accessible through
71 -- rtsfind, otherwise the name clashes with its homonym in Ada.Interrupts.
72
73 type Parameterless_Handler is access protected procedure;
74
75 ----------------------
76 -- General services --
77 ----------------------
78
79 -- Attempt to attach a Handler to an Interrupt to which an Entry is
80 -- already bound will raise a Program_Error.
81
82 function Is_Reserved (Interrupt : Interrupt_ID) return Boolean;
83
84 function Is_Entry_Attached (Interrupt : Interrupt_ID) return Boolean;
85
86 function Is_Handler_Attached (Interrupt : Interrupt_ID) return Boolean;
87
88 function Current_Handler
89 (Interrupt : Interrupt_ID) return Parameterless_Handler;
90
91 -- Calling the following procedures with New_Handler = null and Static =
92 -- true means that we want to modify the current handler regardless of the
93 -- previous handler's binding status. (i.e. we do not care whether it is a
94 -- dynamic or static handler)
95
96 procedure Attach_Handler
97 (New_Handler : Parameterless_Handler;
98 Interrupt : Interrupt_ID;
99 Static : Boolean := False);
100
101 procedure Exchange_Handler
102 (Old_Handler : out Parameterless_Handler;
103 New_Handler : Parameterless_Handler;
104 Interrupt : Interrupt_ID;
105 Static : Boolean := False);
106
107 procedure Detach_Handler
108 (Interrupt : Interrupt_ID;
109 Static : Boolean := False);
110
111 function Reference
112 (Interrupt : Interrupt_ID) return System.Address;
113
114 --------------------------------
115 -- Interrupt Entries Services --
116 --------------------------------
117
118 -- Routines needed for Interrupt Entries
119
120 procedure Bind_Interrupt_To_Entry
121 (T : System.Tasking.Task_Id;
122 E : System.Tasking.Task_Entry_Index;
123 Int_Ref : System.Address);
124 -- Bind the given interrupt to the given entry. If the interrupt is
125 -- already bound to another entry, Program_Error will be raised.
126
127 procedure Detach_Interrupt_Entries (T : System.Tasking.Task_Id);
128 -- This procedure detaches all the Interrupt Entries bound to a task
129
130 ------------------------------
131 -- POSIX.5 Signals Services --
132 ------------------------------
133
134 -- Routines needed for POSIX dot5 POSIX_Signals
135
136 procedure Block_Interrupt (Interrupt : Interrupt_ID);
137 -- Block the Interrupt on the process level
138
139 procedure Unblock_Interrupt (Interrupt : Interrupt_ID);
140
141 function Unblocked_By
142 (Interrupt : Interrupt_ID) return System.Tasking.Task_Id;
143 -- It returns the ID of the last Task which Unblocked this Interrupt.
144 -- It returns Null_Task if no tasks have ever requested the Unblocking
145 -- operation or the Interrupt is currently Blocked.
146
147 function Is_Blocked (Interrupt : Interrupt_ID) return Boolean;
148 -- Comment needed ???
149
150 procedure Ignore_Interrupt (Interrupt : Interrupt_ID);
151 -- Set the sigaction for the interrupt to SIG_IGN
152
153 procedure Unignore_Interrupt (Interrupt : Interrupt_ID);
154 -- Comment needed ???
155
156 function Is_Ignored (Interrupt : Interrupt_ID) return Boolean;
157 -- Comment needed ???
158
159 -- Note : Direct calls to sigaction, sigprocmask, thr_sigsetmask, or any
160 -- other low-level interface that changes the signal action or signal mask
161 -- needs careful thought.
162
163 -- One may achieve the effect of system calls first making RTS blocked (by
164 -- calling Block_Interrupt) for the signal under consideration. This will
165 -- make all the tasks in RTS blocked for the Interrupt.
166
167 ----------------------
168 -- Protection Types --
169 ----------------------
170
171 -- Routines and types needed to implement Interrupt_Handler and
172 -- Attach_Handler.
173
174 -- There are two kinds of protected objects that deal with interrupts:
175
176 -- (1) Only Interrupt_Handler pragmas are used. We need to be able to tell
177 -- if an Interrupt_Handler applies to a given procedure, so
178 -- Register_Interrupt_Handler has to be called for all the potential
179 -- handlers, it should be done by calling Register_Interrupt_Handler with
180 -- the handler code address. On finalization, which can happen only has
181 -- part of library level finalization since PO with Interrupt_Handler
182 -- pragmas can only be declared at library level, nothing special needs to
183 -- be done since the default handlers have been restored as part of task
184 -- completion which is done just before global finalization.
185 -- Dynamic_Interrupt_Protection should be used in this case.
186
187 -- (2) Attach_Handler pragmas are used, and possibly Interrupt_Handler
188 -- pragma. We need to attach the handlers to the given interrupts when the
189 -- object is elaborated. This should be done by constructing an array of
190 -- pairs (interrupt, handler) from the pragmas and calling Install_Handlers
191 -- with it (types to be used are New_Handler_Item and New_Handler_Array).
192 -- On finalization, we need to restore the handlers that were installed
193 -- before the elaboration of the PO, so we need to store these previous
194 -- handlers. This is also done by Install_Handlers, the room for this
195 -- information is provided by adding a discriminant which is the number
196 -- of Attach_Handler pragmas and an array of this size in the protection
197 -- type, Static_Interrupt_Protection.
198
199 procedure Register_Interrupt_Handler
200 (Handler_Addr : System.Address);
201 -- This routine should be called by the compiler to allow the handler be
202 -- used as an Interrupt Handler. That means call this procedure for each
203 -- pragma Interrupt_Handler providing the address of the handler (not
204 -- including the pointer to the actual PO, this way this routine is called
205 -- only once for each type definition of PO).
206
207 type Static_Handler_Index is range 0 .. Integer'Last;
208 subtype Positive_Static_Handler_Index is
209 Static_Handler_Index range 1 .. Static_Handler_Index'Last;
210 -- Comment needed ???
211
212 type Previous_Handler_Item is record
213 Interrupt : Interrupt_ID;
214 Handler : Parameterless_Handler;
215 Static : Boolean;
216 end record;
217 -- Contains all the information needed to restore a previous handler
218
219 type Previous_Handler_Array is array
220 (Positive_Static_Handler_Index range <>) of Previous_Handler_Item;
221
222 type New_Handler_Item is record
223 Interrupt : Interrupt_ID;
224 Handler : Parameterless_Handler;
225 end record;
226 -- Contains all the information from an Attach_Handler pragma
227
228 type New_Handler_Array is
229 array (Positive_Static_Handler_Index range <>) of New_Handler_Item;
230 -- Comment needed ???
231
232 -- Case (1)
233
234 type Dynamic_Interrupt_Protection is new
235 Tasking.Protected_Objects.Entries.Protection_Entries with null record;
236
237 -- ??? Finalize is not overloaded since we currently have no
238 -- way to detach the handlers during library level finalization.
239
240 function Has_Interrupt_Or_Attach_Handler
241 (Object : access Dynamic_Interrupt_Protection) return Boolean;
242 -- Returns True
243
244 -- Case (2)
245
246 type Static_Interrupt_Protection
247 (Num_Entries : Tasking.Protected_Objects.Protected_Entry_Index;
248 Num_Attach_Handler : Static_Handler_Index)
249 is new
250 Tasking.Protected_Objects.Entries.Protection_Entries (Num_Entries) with
251 record
252 Previous_Handlers : Previous_Handler_Array (1 .. Num_Attach_Handler);
253 end record;
254
255 function Has_Interrupt_Or_Attach_Handler
256 (Object : access Static_Interrupt_Protection) return Boolean;
257 -- Returns True
258
259 overriding procedure Finalize (Object : in out Static_Interrupt_Protection);
260 -- Restore previous handlers as required by C.3.1(12) then call
261 -- Finalize (Protection).
262
263 procedure Install_Handlers
264 (Object : access Static_Interrupt_Protection;
265 New_Handlers : New_Handler_Array);
266 -- Store the old handlers in Object.Previous_Handlers and install
267 -- the new static handlers.
268
269 procedure Install_Restricted_Handlers
270 (Prio : Any_Priority;
271 Handlers : New_Handler_Array);
272 -- Install the static Handlers for the given interrupts and do not
273 -- store previously installed handlers. This procedure is used when
274 -- the Ravenscar restrictions are in place since in that case there
275 -- are only library-level protected handlers that will be installed
276 -- at initialization and never be replaced.
277
278 end System.Interrupts;