File : s-intman.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 _ M A N A G E M E N T --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1992-2014, 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 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. --
17 -- --
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 -- This package encapsulates and centralizes information about all uses of
33 -- interrupts (or signals), including the target-dependent mapping of
34 -- interrupts (or signals) to exceptions.
35
36 -- Unlike the original design, System.Interrupt_Management can only be used
37 -- for tasking systems.
38
39 -- PLEASE DO NOT put any subprogram declarations with arguments of type
40 -- Interrupt_ID into the visible part of this package. The type Interrupt_ID
41 -- is used to derive the type in Ada.Interrupts, and adding more operations
42 -- to that type would be illegal according to the Ada Reference Manual. This
43 -- is the reason why the signals sets are implemented using visible arrays
44 -- rather than functions.
45
46 with System.OS_Interface;
47
48 with Interfaces.C;
49
50 package System.Interrupt_Management is
51 pragma Preelaborate;
52
53 type Interrupt_Mask is limited private;
54
55 type Interrupt_ID is new Interfaces.C.int
56 range 0 .. System.OS_Interface.Max_Interrupt;
57
58 type Interrupt_Set is array (Interrupt_ID) of Boolean;
59
60 -- The following objects serve as constants, but are initialized in the
61 -- body to aid portability. This permits us to use more portable names for
62 -- interrupts, where distinct names may map to the same interrupt ID
63 -- value.
64
65 -- For example, suppose SIGRARE is a signal that is not defined on all
66 -- systems, but is always reserved when it is defined. If we have the
67 -- convention that ID zero is not used for any "real" signals, and SIGRARE
68 -- = 0 when SIGRARE is not one of the locally supported signals, we can
69 -- write:
70 -- Reserved (SIGRARE) := True;
71 -- and the initialization code will be portable.
72
73 Abort_Task_Interrupt : Interrupt_ID;
74 -- The interrupt that is used to implement task abort if an interrupt is
75 -- used for that purpose. This is one of the reserved interrupts.
76
77 Keep_Unmasked : Interrupt_Set := (others => False);
78 -- Keep_Unmasked (I) is true iff the interrupt I is one that must be kept
79 -- unmasked at all times, except (perhaps) for short critical sections.
80 -- This includes interrupts that are mapped to exceptions (see
81 -- System.Interrupt_Exceptions.Is_Exception), but may also include
82 -- interrupts (e.g. timer) that need to be kept unmasked for other
83 -- reasons. Where interrupts are implemented as OS signals, and signal
84 -- masking is per-task, the interrupt should be unmasked in ALL TASKS.
85
86 Reserve : Interrupt_Set := (others => False);
87 -- Reserve (I) is true iff the interrupt I is one that cannot be permitted
88 -- to be attached to a user handler. The possible reasons are many. For
89 -- example, it may be mapped to an exception used to implement task abort,
90 -- or used to implement time delays.
91
92 procedure Initialize;
93 -- Initialize the various variables defined in this package. This procedure
94 -- must be called before accessing any object from this package, and can be
95 -- called multiple times.
96
97 private
98 type Interrupt_Mask is new System.OS_Interface.sigset_t;
99 -- In some implementations Interrupt_Mask is represented as a linked list
100
101 procedure Adjust_Context_For_Raise
102 (Signo : System.OS_Interface.Signal;
103 Ucontext : System.Address);
104 pragma Import
105 (C, Adjust_Context_For_Raise, "__gnat_adjust_context_for_raise");
106 -- Target specific hook performing adjustments to the signal's machine
107 -- context, to be called before an exception may be raised from a signal
108 -- handler. This service is provided by init.c, together with the
109 -- non-tasking signal handler.
110
111 end System.Interrupt_Management;