279 lines
12 KiB
Ada
279 lines
12 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
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-- --
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-- S Y S T E M . I N T E R R U P T S --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
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-- --
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-- GNARL is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNARL was developed by the GNARL team at Florida State University. --
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-- Extensive contributions were provided by Ada Core Technologies, Inc. --
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-- --
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------------------------------------------------------------------------------
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-- Note: the compiler generates direct calls to this interface, via Rtsfind.
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-- Any changes to this interface may require corresponding compiler changes.
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-- This package encapsulates the implementation of interrupt or signal
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-- handlers. It is logically an extension of the body of Ada.Interrupts. It
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-- is made a child of System to allow visibility of various runtime system
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-- internal data and operations.
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-- See System.Interrupt_Management for core interrupt/signal interfaces
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-- These two packages are separated to allow System.Interrupt_Management to be
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-- used without requiring the whole tasking implementation to be linked and
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-- elaborated.
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with System.Tasking;
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with System.Tasking.Protected_Objects.Entries;
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with System.OS_Interface;
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package System.Interrupts is
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pragma Elaborate_Body;
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-- Comment needed on why this is here ???
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-------------------------
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-- Constants and types --
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-------------------------
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Default_Interrupt_Priority : constant System.Interrupt_Priority :=
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System.Interrupt_Priority'Last;
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-- Default value used when a pragma Interrupt_Handler or Attach_Handler is
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-- specified without an Interrupt_Priority pragma, see D.3(10).
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type Ada_Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;
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-- Avoid inheritance by Ada.Interrupts.Interrupt_ID of unwanted operations
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type Interrupt_ID is range 0 .. System.OS_Interface.Max_Interrupt;
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subtype System_Interrupt_Id is Interrupt_ID;
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-- This synonym is introduced so that the type is accessible through
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-- rtsfind, otherwise the name clashes with its homonym in Ada.Interrupts.
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type Parameterless_Handler is access protected procedure;
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----------------------
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-- General services --
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----------------------
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-- Attempt to attach a Handler to an Interrupt to which an Entry is
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-- already bound will raise a Program_Error.
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function Is_Reserved (Interrupt : Interrupt_ID) return Boolean;
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function Is_Entry_Attached (Interrupt : Interrupt_ID) return Boolean;
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function Is_Handler_Attached (Interrupt : Interrupt_ID) return Boolean;
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function Current_Handler
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(Interrupt : Interrupt_ID) return Parameterless_Handler;
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-- Calling the following procedures with New_Handler = null and Static =
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-- true means that we want to modify the current handler regardless of the
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-- previous handler's binding status. (i.e. we do not care whether it is a
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-- dynamic or static handler)
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procedure Attach_Handler
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(New_Handler : Parameterless_Handler;
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Interrupt : Interrupt_ID;
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Static : Boolean := False);
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procedure Exchange_Handler
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(Old_Handler : out Parameterless_Handler;
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New_Handler : Parameterless_Handler;
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Interrupt : Interrupt_ID;
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Static : Boolean := False);
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procedure Detach_Handler
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(Interrupt : Interrupt_ID;
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Static : Boolean := False);
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function Reference
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(Interrupt : Interrupt_ID) return System.Address;
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--------------------------------
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-- Interrupt Entries Services --
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--------------------------------
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-- Routines needed for Interrupt Entries
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procedure Bind_Interrupt_To_Entry
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(T : System.Tasking.Task_Id;
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E : System.Tasking.Task_Entry_Index;
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Int_Ref : System.Address);
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-- Bind the given interrupt to the given entry. If the interrupt is
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-- already bound to another entry, Program_Error will be raised.
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procedure Detach_Interrupt_Entries (T : System.Tasking.Task_Id);
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-- This procedure detaches all the Interrupt Entries bound to a task
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------------------------------
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-- POSIX.5 Signals Services --
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------------------------------
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-- Routines needed for POSIX dot5 POSIX_Signals
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procedure Block_Interrupt (Interrupt : Interrupt_ID);
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-- Block the Interrupt on the process level
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procedure Unblock_Interrupt (Interrupt : Interrupt_ID);
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function Unblocked_By
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(Interrupt : Interrupt_ID) return System.Tasking.Task_Id;
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-- It returns the ID of the last Task which Unblocked this Interrupt.
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-- It returns Null_Task if no tasks have ever requested the Unblocking
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-- operation or the Interrupt is currently Blocked.
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function Is_Blocked (Interrupt : Interrupt_ID) return Boolean;
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-- Comment needed ???
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procedure Ignore_Interrupt (Interrupt : Interrupt_ID);
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-- Set the sigaction for the interrupt to SIG_IGN
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procedure Unignore_Interrupt (Interrupt : Interrupt_ID);
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-- Comment needed ???
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function Is_Ignored (Interrupt : Interrupt_ID) return Boolean;
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-- Comment needed ???
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-- Note : Direct calls to sigaction, sigprocmask, thr_sigsetmask, or any
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-- other low-level interface that changes the signal action or signal mask
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-- needs careful thought.
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-- One may achieve the effect of system calls first making RTS blocked (by
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-- calling Block_Interrupt) for the signal under consideration. This will
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-- make all the tasks in RTS blocked for the Interrupt.
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----------------------
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-- Protection Types --
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----------------------
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-- Routines and types needed to implement Interrupt_Handler and
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-- Attach_Handler.
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-- There are two kinds of protected objects that deal with interrupts:
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-- (1) Only Interrupt_Handler pragmas are used. We need to be able to tell
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-- if an Interrupt_Handler applies to a given procedure, so
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-- Register_Interrupt_Handler has to be called for all the potential
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-- handlers, it should be done by calling Register_Interrupt_Handler with
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-- the handler code address. On finalization, which can happen only has
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-- part of library level finalization since PO with Interrupt_Handler
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-- pragmas can only be declared at library level, nothing special needs to
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-- be done since the default handlers have been restored as part of task
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-- completion which is done just before global finalization.
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-- Dynamic_Interrupt_Protection should be used in this case.
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-- (2) Attach_Handler pragmas are used, and possibly Interrupt_Handler
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-- pragma. We need to attach the handlers to the given interrupts when the
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-- object is elaborated. This should be done by constructing an array of
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-- pairs (interrupt, handler) from the pragmas and calling Install_Handlers
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-- with it (types to be used are New_Handler_Item and New_Handler_Array).
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-- On finalization, we need to restore the handlers that were installed
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-- before the elaboration of the PO, so we need to store these previous
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-- handlers. This is also done by Install_Handlers, the room for this
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-- information is provided by adding a discriminant which is the number
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-- of Attach_Handler pragmas and an array of this size in the protection
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-- type, Static_Interrupt_Protection.
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procedure Register_Interrupt_Handler
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(Handler_Addr : System.Address);
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-- This routine should be called by the compiler to allow the handler be
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-- used as an Interrupt Handler. That means call this procedure for each
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-- pragma Interrupt_Handler providing the address of the handler (not
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-- including the pointer to the actual PO, this way this routine is called
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-- only once for each type definition of PO).
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type Static_Handler_Index is range 0 .. Integer'Last;
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subtype Positive_Static_Handler_Index is
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Static_Handler_Index range 1 .. Static_Handler_Index'Last;
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-- Comment needed ???
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type Previous_Handler_Item is record
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Interrupt : Interrupt_ID;
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Handler : Parameterless_Handler;
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Static : Boolean;
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end record;
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-- Contains all the information needed to restore a previous handler
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type Previous_Handler_Array is array
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(Positive_Static_Handler_Index range <>) of Previous_Handler_Item;
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type New_Handler_Item is record
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Interrupt : Interrupt_ID;
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Handler : Parameterless_Handler;
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end record;
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-- Contains all the information from an Attach_Handler pragma
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type New_Handler_Array is
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array (Positive_Static_Handler_Index range <>) of New_Handler_Item;
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-- Comment needed ???
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-- Case (1)
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type Dynamic_Interrupt_Protection is new
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Tasking.Protected_Objects.Entries.Protection_Entries with null record;
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-- ??? Finalize is not overloaded since we currently have no
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-- way to detach the handlers during library level finalization.
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function Has_Interrupt_Or_Attach_Handler
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(Object : access Dynamic_Interrupt_Protection) return Boolean;
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-- Returns True
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-- Case (2)
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type Static_Interrupt_Protection
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(Num_Entries : Tasking.Protected_Objects.Protected_Entry_Index;
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Num_Attach_Handler : Static_Handler_Index)
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is new
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Tasking.Protected_Objects.Entries.Protection_Entries (Num_Entries) with
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record
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Previous_Handlers : Previous_Handler_Array (1 .. Num_Attach_Handler);
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end record;
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function Has_Interrupt_Or_Attach_Handler
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(Object : access Static_Interrupt_Protection) return Boolean;
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-- Returns True
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overriding procedure Finalize (Object : in out Static_Interrupt_Protection);
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-- Restore previous handlers as required by C.3.1(12) then call
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-- Finalize (Protection).
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procedure Install_Handlers
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(Object : access Static_Interrupt_Protection;
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New_Handlers : New_Handler_Array);
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-- Store the old handlers in Object.Previous_Handlers and install
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-- the new static handlers.
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procedure Install_Restricted_Handlers
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(Prio : Any_Priority;
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Handlers : New_Handler_Array);
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-- Install the static Handlers for the given interrupts and do not
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-- store previously installed handlers. This procedure is used when
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-- the Ravenscar restrictions are in place since in that case there
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-- are only library-level protected handlers that will be installed
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-- at initialization and never be replaced.
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end System.Interrupts;
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