gcc/ada/s-interr.ads

   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 S                    --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2001 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- --
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  14 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
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  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
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  18 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
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  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 --  Note: the compiler generates direct calls to this interface, via Rtsfind.
  35 --  Any changes to this interface may require corresponding compiler changes.
  36
  37 --  This package encapsulates the implementation of interrupt or signal
  38 --  handlers.  It is logically an extension of the body of Ada.Interrupts.
  39 --  It is made a child of System to allow visibility of various
  40 --  runtime system internal data and operations.
  41
  42 --  See System.Interrupt_Management for core interrupt/signal interfaces.
  43
  44 --  These two packages are separated in order to allow
  45 --  System.Interrupt_Management to be used without requiring the whole
  46 --  tasking implementation to be linked and elaborated.
  47
  48 with System.Tasking;
  49 --  used for Task_ID
  50
  51 with System.Tasking.Protected_Objects.Entries;
  52 --  used for Protection_Entries
  53
  54 with System.OS_Interface;
  55 --  used for Max_Interrupt
  56
  57 package System.Interrupts is
  58
  59    pragma Elaborate_Body;
  60    --  Comment needed on why this is here ???
  61
  62    -------------------------
  63    -- Constants and types --
  64    -------------------------
  65
  66    Default_Interrupt_Priority : constant System.Interrupt_Priority :=
  67      System.Interrupt_Priority'Last;
  68    --  Default value used when a pragma Interrupt_Handler or Attach_Handler is
  69    --  specified without an Interrupt_Priority pragma, see D.3(10).
  70
  71    type Ada_Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;
  72    --  Avoid inheritance by Ada.Interrupts.Interrupt_ID of unwanted operations
  73
  74    type Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;
  75
  76    type Parameterless_Handler is access protected procedure;
  77
  78    ----------------------
  79    -- General services --
  80    ----------------------
  81
  82    --  Attempt to attach a Handler to an Interrupt to which an Entry is
  83    --  already bound will raise a Program_Error.
  84
  85    function Is_Reserved (Interrupt : Interrupt_ID) return Boolean;
  86
  87    function Is_Entry_Attached (Interrupt : Interrupt_ID) return Boolean;
  88
  89    function Is_Handler_Attached (Interrupt : Interrupt_ID) return Boolean;
  90
  91    function Current_Handler
  92      (Interrupt : Interrupt_ID)
  93       return Parameterless_Handler;
  94
  95    --  Calling the following procedures with New_Handler = null
  96    --  and Static = true means that we want to modify the current handler
  97    --  regardless of the previous handler's binding status.
  98    --  (i.e. we do not care whether it is a dynamic or static handler)
  99
 100    procedure Attach_Handler
 101      (New_Handler : Parameterless_Handler;
 102       Interrupt   : Interrupt_ID;
 103       Static      : Boolean := False);
 104
 105    procedure Exchange_Handler
 106      (Old_Handler : out Parameterless_Handler;
 107       New_Handler : Parameterless_Handler;
 108       Interrupt   : Interrupt_ID;
 109       Static      : Boolean := False);
 110
 111    procedure Detach_Handler
 112      (Interrupt : Interrupt_ID;
 113       Static    : Boolean := False);
 114
 115    function Reference
 116      (Interrupt : Interrupt_ID)
 117      return       System.Address;
 118
 119    ---------------------------------
 120    --  Interrupt entries services --
 121    ---------------------------------
 122
 123    --  Routines needed for Interrupt Entries
 124    --  Attempt to bind an Entry to an Interrupt to which a Handler is
 125    --  already attached will raise a Program_Error.
 126
 127    procedure Bind_Interrupt_To_Entry
 128      (T       : System.Tasking.Task_ID;
 129       E       : System.Tasking.Task_Entry_Index;
 130       Int_Ref : System.Address);
 131
 132    procedure Detach_Interrupt_Entries (T : System.Tasking.Task_ID);
 133    --  This procedure detaches all the Interrupt Entries bound to a task.
 134
 135    -------------------------------
 136    --  POSIX.5 signals services --
 137    -------------------------------
 138
 139    --  Routines needed for POSIX dot5 POSIX_Signals
 140
 141    procedure Block_Interrupt (Interrupt : Interrupt_ID);
 142    --  Block the Interrupt on the process level
 143
 144    procedure Unblock_Interrupt (Interrupt : Interrupt_ID);
 145
 146    function Unblocked_By
 147      (Interrupt   : Interrupt_ID)
 148       return System.Tasking.Task_ID;
 149    --  It returns the ID of the last Task which Unblocked this Interrupt.
 150    --  It returns Null_Task if no tasks have ever requested the
 151    --  Unblocking operation or the Interrupt is currently Blocked.
 152
 153    function Is_Blocked (Interrupt : Interrupt_ID) return Boolean;
 154    --  Comment needed ???
 155
 156    procedure Ignore_Interrupt (Interrupt : Interrupt_ID);
 157    --  Set the sigacion for the interrupt to SIG_IGN.
 158
 159    procedure Unignore_Interrupt (Interrupt : Interrupt_ID);
 160    --  Comment needed ???
 161
 162    function Is_Ignored (Interrupt : Interrupt_ID) return Boolean;
 163    --  Comment needed ???
 164
 165    --  Note : Direct calls to sigaction, sigprocmask, thr_sigsetmask or any
 166    --  other low-level interface that changes the signal action or signal mask
 167    --  needs a careful thought.
 168
 169    --  One may acheive the effect of system calls first making RTS blocked
 170    --  (by calling Block_Interrupt) for the signal under consideration.
 171    --  This will make all the tasks in RTS blocked for the Interrupt.
 172
 173    ----------------------
 174    -- Protection types --
 175    ----------------------
 176
 177    --  Routines and types needed to implement Interrupt_Handler and
 178    --  Attach_Handler.
 179
 180    --  There are two kinds of protected objects that deal with interrupts:
 181
 182    --  (1) Only Interrupt_Handler pragmas are used. We need to be able to
 183    --  tell if an Interrupt_Handler applies to a given procedure, so
 184    --  Register_Interrupt_Handler has to be called for all the potential
 185    --  handlers, it should be done by calling Register_Interrupt_Handler
 186    --  with the handler code address. On finalization, which can happen only
 187    --  has part of library level finalization since PO with
 188    --  Interrupt_Handler pragmas can only be declared at library level,
 189    --  nothing special needs to be done since the default handlers have been
 190    --  restored as part of task completion which is done just before global
 191    --  finalization.  Dynamic_Interrupt_Protection should be used in this
 192    --  case.
 193
 194    --  (2) Attach_Handler pragmas are used, and possibly Interrupt_Handler
 195    --  pragma. We need to attach the handlers to the given interrupts when
 196    --  the objet is elaborated. This should be done by constructing an array
 197    --  of pairs (interrupt, handler) from the pragmas and calling
 198    --  Install_Handlers with it (types to be used are New_Handler_Item and
 199    --  New_Handler_Array). On finalization, we need to restore the handlers
 200    --  that were installed before the elaboration of the PO, so we need to
 201    --  store these previous handlers. This is also done by Install_Handlers,
 202    --  the room for these informations is provided by adding a discriminant
 203    --  which is the number of Attach_Handler pragmas and an array of this
 204    --  size in the protection type, Static_Interrupt_Protection.
 205
 206    procedure Register_Interrupt_Handler
 207      (Handler_Addr : System.Address);
 208    --  This routine should be called by the compiler to allow the
 209    --  handler be used as an Interrupt Handler. That means call this
 210    --  procedure for each pragma Interrup_Handler providing the
 211    --  address of the handler (not including the pointer to the
 212    --  actual PO, this way this routine is called only once for
 213    --  each type definition of PO).
 214
 215    type Static_Handler_Index is range 0 .. Integer'Last;
 216    subtype Positive_Static_Handler_Index is
 217      Static_Handler_Index range 1 .. Static_Handler_Index'Last;
 218    --  Comment needed ???
 219
 220    type Previous_Handler_Item is record
 221       Interrupt : Interrupt_ID;
 222       Handler   : Parameterless_Handler;
 223       Static    : Boolean;
 224    end record;
 225    --  Contains all the information needed to restore a previous handler.
 226
 227    type Previous_Handler_Array is array
 228      (Positive_Static_Handler_Index range <>) of Previous_Handler_Item;
 229
 230    type New_Handler_Item is record
 231       Interrupt : Interrupt_ID;
 232       Handler   : Parameterless_Handler;
 233    end record;
 234    --  Contains all the information from an Attach_Handler pragma.
 235
 236    type New_Handler_Array is
 237      array (Positive_Static_Handler_Index range <>) of New_Handler_Item;
 238    --  Comment needed ???
 239
 240    --  Case (1)
 241
 242    type Dynamic_Interrupt_Protection is new
 243      Tasking.Protected_Objects.Entries.Protection_Entries with null record;
 244
 245    --  ??? Finalize is not overloaded since we currently have no
 246    --  way to detach the handlers during library level finalization.
 247
 248    function Has_Interrupt_Or_Attach_Handler
 249      (Object : access Dynamic_Interrupt_Protection) return Boolean;
 250    --  Returns True.
 251
 252    --  Case (2)
 253
 254    type Static_Interrupt_Protection
 255      (Num_Entries        : Tasking.Protected_Objects.Protected_Entry_Index;
 256       Num_Attach_Handler : Static_Handler_Index)
 257    is new
 258      Tasking.Protected_Objects.Entries.Protection_Entries (Num_Entries) with
 259      record
 260        Previous_Handlers : Previous_Handler_Array (1 .. Num_Attach_Handler);
 261      end record;
 262
 263    function Has_Interrupt_Or_Attach_Handler
 264      (Object : access Static_Interrupt_Protection)
 265       return   Boolean;
 266    --  Returns True.
 267
 268    procedure Finalize (Object : in out Static_Interrupt_Protection);
 269    --  Restore previous handlers as required by C.3.1(12) then call
 270    --  Finalize (Protection).
 271
 272    procedure Install_Handlers
 273      (Object       : access Static_Interrupt_Protection;
 274       New_Handlers : in New_Handler_Array);
 275    --  Store the old handlers in Object.Previous_Handlers and install
 276    --  the new static handlers.
 277
 278 end System.Interrupts;