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diff --git a/gcc/ada/s-interr.adb b/gcc/ada/s-interr.adb new file mode 100644 index 000000000..3d33f6c9e --- /dev/null +++ b/gcc/ada/s-interr.adb @@ -0,0 +1,1467 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- +-- -- +-- S Y S T E M . I N T E R R U P T S -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2009, 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. -- +-- -- +------------------------------------------------------------------------------ + +-- Invariants: + +-- All user-handleable interrupts are masked at all times in all +-- tasks/threads except possibly for the Interrupt_Manager task. + +-- When a user task wants to have the effect of masking/unmasking an +-- interrupt, it must call Block_Interrupt/Unblock_Interrupt, which +-- will have the effect of unmasking/masking the interrupt in the +-- Interrupt_Manager task. + +-- Note : Direct calls to sigaction, sigprocmask, pthread_sigsetmask or any +-- other low-level interface that changes the interrupt action or +-- interrupt mask needs a careful thought. +-- One may achieve the effect of system calls first masking RTS blocked +-- (by calling Block_Interrupt) for the interrupt under consideration. +-- This will make all the tasks in RTS blocked for the Interrupt. + +-- Once we associate a Server_Task with an interrupt, the task never +-- goes away, and we never remove the association. + +-- There is no more than one interrupt per Server_Task and no more than +-- one Server_Task per interrupt. + +with Ada.Task_Identification; + +with System.Task_Primitives; +with System.Interrupt_Management; + +with System.Interrupt_Management.Operations; +pragma Elaborate_All (System.Interrupt_Management.Operations); + +with System.Task_Primitives.Operations; +with System.Task_Primitives.Interrupt_Operations; +with System.Storage_Elements; +with System.Tasking.Utilities; + +with System.Tasking.Rendezvous; +pragma Elaborate_All (System.Tasking.Rendezvous); + +with System.Tasking.Initialization; +with System.Parameters; + +with Ada.Unchecked_Conversion; + +package body System.Interrupts is + + use Parameters; + use Tasking; + + package POP renames System.Task_Primitives.Operations; + package PIO renames System.Task_Primitives.Interrupt_Operations; + package IMNG renames System.Interrupt_Management; + package IMOP renames System.Interrupt_Management.Operations; + + function To_System is new Ada.Unchecked_Conversion + (Ada.Task_Identification.Task_Id, Task_Id); + + ----------------- + -- Local Tasks -- + ----------------- + + -- WARNING: System.Tasking.Stages performs calls to this task with + -- low-level constructs. Do not change this spec without synchronizing it. + + task Interrupt_Manager is + entry Detach_Interrupt_Entries (T : Task_Id); + + entry Initialize (Mask : IMNG.Interrupt_Mask); + + entry Attach_Handler + (New_Handler : Parameterless_Handler; + Interrupt : Interrupt_ID; + Static : Boolean; + Restoration : Boolean := False); + + entry Exchange_Handler + (Old_Handler : out Parameterless_Handler; + New_Handler : Parameterless_Handler; + Interrupt : Interrupt_ID; + Static : Boolean); + + entry Detach_Handler + (Interrupt : Interrupt_ID; + Static : Boolean); + + entry Bind_Interrupt_To_Entry + (T : Task_Id; + E : Task_Entry_Index; + Interrupt : Interrupt_ID); + + entry Block_Interrupt (Interrupt : Interrupt_ID); + + entry Unblock_Interrupt (Interrupt : Interrupt_ID); + + entry Ignore_Interrupt (Interrupt : Interrupt_ID); + + entry Unignore_Interrupt (Interrupt : Interrupt_ID); + + pragma Interrupt_Priority (System.Interrupt_Priority'Last); + end Interrupt_Manager; + + task type Server_Task (Interrupt : Interrupt_ID) is + pragma Priority (System.Interrupt_Priority'Last); + -- Note: the above pragma Priority is strictly speaking improper since + -- it is outside the range of allowed priorities, but the compiler + -- treats system units specially and does not apply this range checking + -- rule to system units. + + end Server_Task; + + type Server_Task_Access is access Server_Task; + + ------------------------------- + -- Local Types and Variables -- + ------------------------------- + + type Entry_Assoc is record + T : Task_Id; + E : Task_Entry_Index; + end record; + + type Handler_Assoc is record + H : Parameterless_Handler; + Static : Boolean; -- Indicates static binding; + end record; + + User_Handler : array (Interrupt_ID'Range) of Handler_Assoc := + (others => (null, Static => False)); + pragma Volatile_Components (User_Handler); + -- Holds the protected procedure handler (if any) and its Static + -- information for each interrupt. A handler is a Static one if it is + -- specified through the pragma Attach_Handler. Attach_Handler. Otherwise, + -- not static) + + User_Entry : array (Interrupt_ID'Range) of Entry_Assoc := + (others => (T => Null_Task, E => Null_Task_Entry)); + pragma Volatile_Components (User_Entry); + -- Holds the task and entry index (if any) for each interrupt + + Blocked : array (Interrupt_ID'Range) of Boolean := (others => False); + pragma Atomic_Components (Blocked); + -- True iff the corresponding interrupt is blocked in the process level + + Ignored : array (Interrupt_ID'Range) of Boolean := (others => False); + pragma Atomic_Components (Ignored); + -- True iff the corresponding interrupt is blocked in the process level + + Last_Unblocker : + array (Interrupt_ID'Range) of Task_Id := (others => Null_Task); + pragma Atomic_Components (Last_Unblocker); + -- Holds the ID of the last Task which Unblocked this Interrupt. It + -- contains Null_Task if no tasks have ever requested the Unblocking + -- operation or the Interrupt is currently Blocked. + + Server_ID : array (Interrupt_ID'Range) of Task_Id := + (others => Null_Task); + pragma Atomic_Components (Server_ID); + -- Holds the Task_Id of the Server_Task for each interrupt. Task_Id is + -- needed to accomplish locking per Interrupt base. Also is needed to + -- decide whether to create a new Server_Task. + + -- Type and Head, Tail of the list containing Registered Interrupt + -- Handlers. These definitions are used to register the handlers + -- specified by the pragma Interrupt_Handler. + + type Registered_Handler; + type R_Link is access all Registered_Handler; + + type Registered_Handler is record + H : System.Address := System.Null_Address; + Next : R_Link := null; + end record; + + Registered_Handler_Head : R_Link := null; + Registered_Handler_Tail : R_Link := null; + + Access_Hold : Server_Task_Access; + -- Variable used to allocate Server_Task using "new" + + ----------------------- + -- Local Subprograms -- + ----------------------- + + function Is_Registered (Handler : Parameterless_Handler) return Boolean; + -- See if the Handler has been "pragma"ed using Interrupt_Handler. Always + -- consider a null handler as registered. + + -------------------- + -- Attach_Handler -- + -------------------- + + -- Calling this procedure with New_Handler = null and Static = True means + -- we want to detach the current handler regardless of the previous + -- handler's binding status (i.e. do not care if it is a dynamic or static + -- handler). + + -- This option is needed so that during the finalization of a PO, we can + -- detach handlers attached through pragma Attach_Handler. + + procedure Attach_Handler + (New_Handler : Parameterless_Handler; + Interrupt : Interrupt_ID; + Static : Boolean := False) + is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + Interrupt_Manager.Attach_Handler (New_Handler, Interrupt, Static); + + end Attach_Handler; + + ----------------------------- + -- Bind_Interrupt_To_Entry -- + ----------------------------- + + -- This procedure raises a Program_Error if it tries to bind an interrupt + -- to which an Entry or a Procedure is already bound. + + procedure Bind_Interrupt_To_Entry + (T : Task_Id; + E : Task_Entry_Index; + Int_Ref : System.Address) + is + Interrupt : constant Interrupt_ID := + Interrupt_ID (Storage_Elements.To_Integer (Int_Ref)); + + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + Interrupt_Manager.Bind_Interrupt_To_Entry (T, E, Interrupt); + end Bind_Interrupt_To_Entry; + + --------------------- + -- Block_Interrupt -- + --------------------- + + procedure Block_Interrupt (Interrupt : Interrupt_ID) is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + Interrupt_Manager.Block_Interrupt (Interrupt); + end Block_Interrupt; + + --------------------- + -- Current_Handler -- + --------------------- + + function Current_Handler + (Interrupt : Interrupt_ID) return Parameterless_Handler + is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + -- ??? Since Parameterless_Handler is not Atomic, the current + -- implementation is wrong. We need a new service in Interrupt_Manager + -- to ensure atomicity. + + return User_Handler (Interrupt).H; + end Current_Handler; + + -------------------- + -- Detach_Handler -- + -------------------- + + -- Calling this procedure with Static = True means we want to Detach the + -- current handler regardless of the previous handler's binding status + -- (i.e. do not care if it is a dynamic or static handler). + + -- This option is needed so that during the finalization of a PO, we can + -- detach handlers attached through pragma Attach_Handler. + + procedure Detach_Handler + (Interrupt : Interrupt_ID; + Static : Boolean := False) + is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + Interrupt_Manager.Detach_Handler (Interrupt, Static); + end Detach_Handler; + + ------------------------------ + -- Detach_Interrupt_Entries -- + ------------------------------ + + procedure Detach_Interrupt_Entries (T : Task_Id) is + begin + Interrupt_Manager.Detach_Interrupt_Entries (T); + end Detach_Interrupt_Entries; + + ---------------------- + -- Exchange_Handler -- + ---------------------- + + -- Calling this procedure with New_Handler = null and Static = True means + -- we want to detach the current handler regardless of the previous + -- handler's binding status (i.e. do not care if it is a dynamic or static + -- handler). + + -- This option is needed so that during the finalization of a PO, we can + -- detach handlers attached through pragma Attach_Handler. + + procedure Exchange_Handler + (Old_Handler : out Parameterless_Handler; + New_Handler : Parameterless_Handler; + Interrupt : Interrupt_ID; + Static : Boolean := False) + is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + Interrupt_Manager.Exchange_Handler + (Old_Handler, New_Handler, Interrupt, Static); + end Exchange_Handler; + + -------------- + -- Finalize -- + -------------- + + procedure Finalize (Object : in out Static_Interrupt_Protection) is + function State + (Int : System.Interrupt_Management.Interrupt_ID) return Character; + pragma Import (C, State, "__gnat_get_interrupt_state"); + -- Get interrupt state for interrupt number Int. Defined in init.c + + Default : constant Character := 's'; + -- 's' Interrupt_State pragma set state to System (use "default" + -- system handler) + + begin + -- ??? loop to be executed only when we're not doing library level + -- finalization, since in this case all interrupt tasks are gone. + + -- If the Abort_Task signal is set to system, it means that we cannot + -- reset interrupt handlers since this would require sending the abort + -- signal to the Server_Task + + if not Interrupt_Manager'Terminated + and then State (System.Interrupt_Management.Abort_Task_Interrupt) + /= Default + then + for N in reverse Object.Previous_Handlers'Range loop + Interrupt_Manager.Attach_Handler + (New_Handler => Object.Previous_Handlers (N).Handler, + Interrupt => Object.Previous_Handlers (N).Interrupt, + Static => Object.Previous_Handlers (N).Static, + Restoration => True); + end loop; + end if; + + Tasking.Protected_Objects.Entries.Finalize + (Tasking.Protected_Objects.Entries.Protection_Entries (Object)); + end Finalize; + + ------------------------------------- + -- Has_Interrupt_Or_Attach_Handler -- + ------------------------------------- + + -- Need comments as to why these always return True ??? + + function Has_Interrupt_Or_Attach_Handler + (Object : access Dynamic_Interrupt_Protection) return Boolean + is + pragma Unreferenced (Object); + begin + return True; + end Has_Interrupt_Or_Attach_Handler; + + function Has_Interrupt_Or_Attach_Handler + (Object : access Static_Interrupt_Protection) return Boolean + is + pragma Unreferenced (Object); + begin + return True; + end Has_Interrupt_Or_Attach_Handler; + + ---------------------- + -- Ignore_Interrupt -- + ---------------------- + + procedure Ignore_Interrupt (Interrupt : Interrupt_ID) is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + Interrupt_Manager.Ignore_Interrupt (Interrupt); + end Ignore_Interrupt; + + ---------------------- + -- Install_Handlers -- + ---------------------- + + procedure Install_Handlers + (Object : access Static_Interrupt_Protection; + New_Handlers : New_Handler_Array) + is + begin + for N in New_Handlers'Range loop + + -- We need a lock around this ??? + + Object.Previous_Handlers (N).Interrupt := New_Handlers (N).Interrupt; + Object.Previous_Handlers (N).Static := User_Handler + (New_Handlers (N).Interrupt).Static; + + -- We call Exchange_Handler and not directly Interrupt_Manager. + -- Exchange_Handler so we get the Is_Reserved check. + + Exchange_Handler + (Old_Handler => Object.Previous_Handlers (N).Handler, + New_Handler => New_Handlers (N).Handler, + Interrupt => New_Handlers (N).Interrupt, + Static => True); + end loop; + end Install_Handlers; + + --------------------------------- + -- Install_Restricted_Handlers -- + --------------------------------- + + procedure Install_Restricted_Handlers (Handlers : New_Handler_Array) is + begin + for N in Handlers'Range loop + Attach_Handler (Handlers (N).Handler, Handlers (N).Interrupt, True); + end loop; + end Install_Restricted_Handlers; + + ---------------- + -- Is_Blocked -- + ---------------- + + function Is_Blocked (Interrupt : Interrupt_ID) return Boolean is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + return Blocked (Interrupt); + end Is_Blocked; + + ----------------------- + -- Is_Entry_Attached -- + ----------------------- + + function Is_Entry_Attached (Interrupt : Interrupt_ID) return Boolean is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + return User_Entry (Interrupt).T /= Null_Task; + end Is_Entry_Attached; + + ------------------------- + -- Is_Handler_Attached -- + ------------------------- + + function Is_Handler_Attached (Interrupt : Interrupt_ID) return Boolean is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + return User_Handler (Interrupt).H /= null; + end Is_Handler_Attached; + + ---------------- + -- Is_Ignored -- + ---------------- + + function Is_Ignored (Interrupt : Interrupt_ID) return Boolean is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + return Ignored (Interrupt); + end Is_Ignored; + + ------------------- + -- Is_Registered -- + ------------------- + + function Is_Registered (Handler : Parameterless_Handler) return Boolean is + + type Fat_Ptr is record + Object_Addr : System.Address; + Handler_Addr : System.Address; + end record; + + function To_Fat_Ptr is new Ada.Unchecked_Conversion + (Parameterless_Handler, Fat_Ptr); + + Ptr : R_Link; + Fat : Fat_Ptr; + + begin + if Handler = null then + return True; + end if; + + Fat := To_Fat_Ptr (Handler); + + Ptr := Registered_Handler_Head; + + while Ptr /= null loop + if Ptr.H = Fat.Handler_Addr then + return True; + end if; + + Ptr := Ptr.Next; + end loop; + + return False; + end Is_Registered; + + ----------------- + -- Is_Reserved -- + ----------------- + + function Is_Reserved (Interrupt : Interrupt_ID) return Boolean is + begin + return IMNG.Reserve (IMNG.Interrupt_ID (Interrupt)); + end Is_Reserved; + + --------------- + -- Reference -- + --------------- + + function Reference (Interrupt : Interrupt_ID) return System.Address is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + return Storage_Elements.To_Address + (Storage_Elements.Integer_Address (Interrupt)); + end Reference; + + --------------------------------- + -- Register_Interrupt_Handler -- + --------------------------------- + + procedure Register_Interrupt_Handler (Handler_Addr : System.Address) is + New_Node_Ptr : R_Link; + + begin + -- This routine registers the Handler as usable for Dynamic Interrupt + -- Handler. Routines attaching and detaching Handler dynamically should + -- first consult if the Handler is registered. A Program Error should + -- be raised if it is not registered. + + -- The pragma Interrupt_Handler can only appear in the library level PO + -- definition and instantiation. Therefore, we do not need to implement + -- Unregistering operation. Neither we need to protect the queue + -- structure using a Lock. + + pragma Assert (Handler_Addr /= System.Null_Address); + + New_Node_Ptr := new Registered_Handler; + New_Node_Ptr.H := Handler_Addr; + + if Registered_Handler_Head = null then + Registered_Handler_Head := New_Node_Ptr; + Registered_Handler_Tail := New_Node_Ptr; + + else + Registered_Handler_Tail.Next := New_Node_Ptr; + Registered_Handler_Tail := New_Node_Ptr; + end if; + end Register_Interrupt_Handler; + + ----------------------- + -- Unblock_Interrupt -- + ----------------------- + + procedure Unblock_Interrupt (Interrupt : Interrupt_ID) is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + Interrupt_Manager.Unblock_Interrupt (Interrupt); + end Unblock_Interrupt; + + ------------------ + -- Unblocked_By -- + ------------------ + + function Unblocked_By + (Interrupt : Interrupt_ID) return System.Tasking.Task_Id + is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + return Last_Unblocker (Interrupt); + end Unblocked_By; + + ------------------------ + -- Unignore_Interrupt -- + ------------------------ + + procedure Unignore_Interrupt (Interrupt : Interrupt_ID) is + begin + if Is_Reserved (Interrupt) then + raise Program_Error with + "Interrupt" & Interrupt_ID'Image (Interrupt) & " is reserved"; + end if; + + Interrupt_Manager.Unignore_Interrupt (Interrupt); + end Unignore_Interrupt; + + ----------------------- + -- Interrupt_Manager -- + ----------------------- + + task body Interrupt_Manager is + + --------------------- + -- Local Variables -- + --------------------- + + Intwait_Mask : aliased IMNG.Interrupt_Mask; + Ret_Interrupt : Interrupt_ID; + Old_Mask : aliased IMNG.Interrupt_Mask; + Old_Handler : Parameterless_Handler; + + -------------------- + -- Local Routines -- + -------------------- + + procedure Bind_Handler (Interrupt : Interrupt_ID); + -- This procedure does not do anything if the Interrupt is blocked. + -- Otherwise, we have to interrupt Server_Task for status change through + -- Wakeup interrupt. + + procedure Unbind_Handler (Interrupt : Interrupt_ID); + -- This procedure does not do anything if the Interrupt is blocked. + -- Otherwise, we have to interrupt Server_Task for status change + -- through abort interrupt. + + procedure Unprotected_Exchange_Handler + (Old_Handler : out Parameterless_Handler; + New_Handler : Parameterless_Handler; + Interrupt : Interrupt_ID; + Static : Boolean; + Restoration : Boolean := False); + + procedure Unprotected_Detach_Handler + (Interrupt : Interrupt_ID; + Static : Boolean); + + ------------------ + -- Bind_Handler -- + ------------------ + + procedure Bind_Handler (Interrupt : Interrupt_ID) is + begin + if not Blocked (Interrupt) then + + -- Mask this task for the given Interrupt so that all tasks + -- are masked for the Interrupt and the actual delivery of the + -- Interrupt will be caught using "sigwait" by the + -- corresponding Server_Task. + + IMOP.Thread_Block_Interrupt (IMNG.Interrupt_ID (Interrupt)); + + -- We have installed a Handler or an Entry before we called + -- this procedure. If the Handler Task is waiting to be awakened, + -- do it here. Otherwise, the interrupt will be discarded. + + POP.Wakeup (Server_ID (Interrupt), Interrupt_Server_Idle_Sleep); + end if; + end Bind_Handler; + + -------------------- + -- Unbind_Handler -- + -------------------- + + procedure Unbind_Handler (Interrupt : Interrupt_ID) is + Server : System.Tasking.Task_Id; + begin + if not Blocked (Interrupt) then + -- Currently, there is a Handler or an Entry attached and + -- corresponding Server_Task is waiting on "sigwait." + -- We have to wake up the Server_Task and make it + -- wait on condition variable by sending an + -- Abort_Task_Interrupt + + Server := Server_ID (Interrupt); + + case Server.Common.State is + when Interrupt_Server_Idle_Sleep | + Interrupt_Server_Blocked_Interrupt_Sleep + => + POP.Wakeup (Server, Server.Common.State); + + when Interrupt_Server_Blocked_On_Event_Flag => + POP.Abort_Task (Server); + + -- Make sure corresponding Server_Task is out of its + -- own sigwait state. + + Ret_Interrupt := + Interrupt_ID (IMOP.Interrupt_Wait (Intwait_Mask'Access)); + pragma Assert + (Ret_Interrupt = Interrupt_ID (IMNG.Abort_Task_Interrupt)); + + when Runnable => + null; + + when others => + pragma Assert (False); + null; + end case; + + IMOP.Install_Default_Action (IMNG.Interrupt_ID (Interrupt)); + + -- Unmake the Interrupt for this task in order to allow default + -- action again. + + IMOP.Thread_Unblock_Interrupt (IMNG.Interrupt_ID (Interrupt)); + + else + IMOP.Install_Default_Action (IMNG.Interrupt_ID (Interrupt)); + end if; + end Unbind_Handler; + + -------------------------------- + -- Unprotected_Detach_Handler -- + -------------------------------- + + procedure Unprotected_Detach_Handler + (Interrupt : Interrupt_ID; + Static : Boolean) + is + Old_Handler : Parameterless_Handler; + + begin + if User_Entry (Interrupt).T /= Null_Task then + + -- In case we have an Interrupt Entry installed. + -- raise a program error. (propagate it to the caller). + + raise Program_Error with + "An interrupt entry is already installed"; + end if; + + -- Note : Static = True will pass the following check. That is the + -- case when we want to detach a handler regardless of the static + -- status of the current_Handler. + + if not Static and then User_Handler (Interrupt).Static then + + -- Tries to detach a static Interrupt Handler. + -- raise a program error. + + raise Program_Error with + "Trying to detach a static Interrupt Handler"; + end if; + + -- The interrupt should no longer be ignored if + -- it was ever ignored. + + Ignored (Interrupt) := False; + + Old_Handler := User_Handler (Interrupt).H; + + -- The new handler + + User_Handler (Interrupt).H := null; + User_Handler (Interrupt).Static := False; + + if Old_Handler /= null then + Unbind_Handler (Interrupt); + end if; + end Unprotected_Detach_Handler; + + ---------------------------------- + -- Unprotected_Exchange_Handler -- + ---------------------------------- + + procedure Unprotected_Exchange_Handler + (Old_Handler : out Parameterless_Handler; + New_Handler : Parameterless_Handler; + Interrupt : Interrupt_ID; + Static : Boolean; + Restoration : Boolean := False) + is + begin + if User_Entry (Interrupt).T /= Null_Task then + + -- In case we have an Interrupt Entry already installed. + -- raise a program error. (propagate it to the caller). + + raise Program_Error with + "An interrupt is already installed"; + end if; + + -- Note : A null handler with Static = True will pass the + -- following check. That is the case when we want to Detach a + -- handler regardless of the Static status of the current_Handler. + + -- We don't check anything if Restoration is True, since we + -- may be detaching a static handler to restore a dynamic one. + + if not Restoration and then not Static + + -- Tries to overwrite a static Interrupt Handler with a + -- dynamic Handler + + and then (User_Handler (Interrupt).Static + + -- The new handler is not specified as an + -- Interrupt Handler by a pragma. + + or else not Is_Registered (New_Handler)) + then + raise Program_Error with + "Trying to overwrite a static Interrupt Handler with a " & + "dynamic Handler"; + end if; + + -- The interrupt should no longer be ignored if + -- it was ever ignored. + + Ignored (Interrupt) := False; + + -- Save the old handler + + Old_Handler := User_Handler (Interrupt).H; + + -- The new handler + + User_Handler (Interrupt).H := New_Handler; + + if New_Handler = null then + + -- The null handler means we are detaching the handler + + User_Handler (Interrupt).Static := False; + + else + User_Handler (Interrupt).Static := Static; + end if; + + -- Invoke a corresponding Server_Task if not yet created. + -- Place Task_Id info in Server_ID array. + + if Server_ID (Interrupt) = Null_Task then + + -- When a new Server_Task is created, it should have its + -- signal mask set to the All_Tasks_Mask. + + IMOP.Set_Interrupt_Mask + (IMOP.All_Tasks_Mask'Access, Old_Mask'Access); + Access_Hold := new Server_Task (Interrupt); + IMOP.Set_Interrupt_Mask (Old_Mask'Access); + + Server_ID (Interrupt) := To_System (Access_Hold.all'Identity); + end if; + + if New_Handler = null then + if Old_Handler /= null then + Unbind_Handler (Interrupt); + end if; + + return; + end if; + + if Old_Handler = null then + Bind_Handler (Interrupt); + end if; + end Unprotected_Exchange_Handler; + + -- Start of processing for Interrupt_Manager + + begin + -- By making this task independent of master, when the process + -- goes away, the Interrupt_Manager will terminate gracefully. + + System.Tasking.Utilities.Make_Independent; + + -- Environment task gets its own interrupt mask, saves it, + -- and then masks all interrupts except the Keep_Unmasked set. + + -- During rendezvous, the Interrupt_Manager receives the old + -- interrupt mask of the environment task, and sets its own + -- interrupt mask to that value. + + -- The environment task will call the entry of Interrupt_Manager some + -- during elaboration of the body of this package. + + accept Initialize (Mask : IMNG.Interrupt_Mask) do + declare + The_Mask : aliased IMNG.Interrupt_Mask; + + begin + IMOP.Copy_Interrupt_Mask (The_Mask, Mask); + IMOP.Set_Interrupt_Mask (The_Mask'Access); + end; + end Initialize; + + -- Note: All tasks in RTS will have all the Reserve Interrupts + -- being masked (except the Interrupt_Manager) and Keep_Unmasked + -- unmasked when created. + + -- Abort_Task_Interrupt is one of the Interrupt unmasked + -- in all tasks. We mask the Interrupt in this particular task + -- so that "sigwait" is possible to catch an explicitly sent + -- Abort_Task_Interrupt from the Server_Tasks. + + -- This sigwaiting is needed so that we make sure a Server_Task is + -- out of its own sigwait state. This extra synchronization is + -- necessary to prevent following scenarios. + + -- 1) Interrupt_Manager sends an Abort_Task_Interrupt to the + -- Server_Task then changes its own interrupt mask (OS level). + -- If an interrupt (corresponding to the Server_Task) arrives + -- in the mean time we have the Interrupt_Manager unmasked and + -- the Server_Task waiting on sigwait. + + -- 2) For unbinding handler, we install a default action in the + -- Interrupt_Manager. POSIX.1c states that the result of using + -- "sigwait" and "sigaction" simultaneously on the same interrupt + -- is undefined. Therefore, we need to be informed from the + -- Server_Task of the fact that the Server_Task is out of its + -- sigwait stage. + + IMOP.Empty_Interrupt_Mask (Intwait_Mask'Access); + IMOP.Add_To_Interrupt_Mask + (Intwait_Mask'Access, IMNG.Abort_Task_Interrupt); + IMOP.Thread_Block_Interrupt + (IMNG.Abort_Task_Interrupt); + + loop + -- A block is needed to absorb Program_Error exception + + begin + select + accept Attach_Handler + (New_Handler : Parameterless_Handler; + Interrupt : Interrupt_ID; + Static : Boolean; + Restoration : Boolean := False) + do + Unprotected_Exchange_Handler + (Old_Handler, New_Handler, Interrupt, Static, Restoration); + end Attach_Handler; + + or + accept Exchange_Handler + (Old_Handler : out Parameterless_Handler; + New_Handler : Parameterless_Handler; + Interrupt : Interrupt_ID; + Static : Boolean) + do + Unprotected_Exchange_Handler + (Old_Handler, New_Handler, Interrupt, Static); + end Exchange_Handler; + + or + accept Detach_Handler + (Interrupt : Interrupt_ID; + Static : Boolean) + do + Unprotected_Detach_Handler (Interrupt, Static); + end Detach_Handler; + + or + accept Bind_Interrupt_To_Entry + (T : Task_Id; + E : Task_Entry_Index; + Interrupt : Interrupt_ID) + do + -- if there is a binding already (either a procedure or an + -- entry), raise Program_Error (propagate it to the caller). + + if User_Handler (Interrupt).H /= null + or else User_Entry (Interrupt).T /= Null_Task + then + raise Program_Error with + "A binding for this interrupt is already present"; + end if; + + -- The interrupt should no longer be ignored if + -- it was ever ignored. + + Ignored (Interrupt) := False; + User_Entry (Interrupt) := Entry_Assoc'(T => T, E => E); + + -- Indicate the attachment of Interrupt Entry in ATCB. + -- This is need so that when an Interrupt Entry task + -- terminates the binding can be cleaned. The call to + -- unbinding must be made by the task before it terminates. + + T.Interrupt_Entry := True; + + -- Invoke a corresponding Server_Task if not yet created. + -- Place Task_Id info in Server_ID array. + + if Server_ID (Interrupt) = Null_Task then + + -- When a new Server_Task is created, it should have its + -- signal mask set to the All_Tasks_Mask. + + IMOP.Set_Interrupt_Mask + (IMOP.All_Tasks_Mask'Access, Old_Mask'Access); + Access_Hold := new Server_Task (Interrupt); + IMOP.Set_Interrupt_Mask (Old_Mask'Access); + Server_ID (Interrupt) := + To_System (Access_Hold.all'Identity); + end if; + + Bind_Handler (Interrupt); + end Bind_Interrupt_To_Entry; + + or + accept Detach_Interrupt_Entries (T : Task_Id) do + for J in Interrupt_ID'Range loop + if not Is_Reserved (J) then + if User_Entry (J).T = T then + + -- The interrupt should no longer be ignored if + -- it was ever ignored. + + Ignored (J) := False; + User_Entry (J) := Entry_Assoc' + (T => Null_Task, E => Null_Task_Entry); + Unbind_Handler (J); + end if; + end if; + end loop; + + -- Indicate in ATCB that no Interrupt Entries are attached + + T.Interrupt_Entry := False; + end Detach_Interrupt_Entries; + + or + accept Block_Interrupt (Interrupt : Interrupt_ID) do + if Blocked (Interrupt) then + return; + end if; + + Blocked (Interrupt) := True; + Last_Unblocker (Interrupt) := Null_Task; + + -- Mask this task for the given Interrupt so that all tasks + -- are masked for the Interrupt. + + IMOP.Thread_Block_Interrupt (IMNG.Interrupt_ID (Interrupt)); + + if User_Handler (Interrupt).H /= null + or else User_Entry (Interrupt).T /= Null_Task + then + -- This is the case where the Server_Task is waiting + -- on "sigwait." Wake it up by sending an + -- Abort_Task_Interrupt so that the Server_Task + -- waits on Cond. + + POP.Abort_Task (Server_ID (Interrupt)); + + -- Make sure corresponding Server_Task is out of its own + -- sigwait state. + + Ret_Interrupt := Interrupt_ID + (IMOP.Interrupt_Wait (Intwait_Mask'Access)); + pragma Assert + (Ret_Interrupt = + Interrupt_ID (IMNG.Abort_Task_Interrupt)); + end if; + end Block_Interrupt; + + or + accept Unblock_Interrupt (Interrupt : Interrupt_ID) do + if not Blocked (Interrupt) then + return; + end if; + + Blocked (Interrupt) := False; + Last_Unblocker (Interrupt) := + To_System (Unblock_Interrupt'Caller); + + if User_Handler (Interrupt).H = null + and then User_Entry (Interrupt).T = Null_Task + then + -- No handler is attached. Unmask the Interrupt so that + -- the default action can be carried out. + + IMOP.Thread_Unblock_Interrupt + (IMNG.Interrupt_ID (Interrupt)); + + else + -- The Server_Task must be waiting on the Cond variable + -- since it was being blocked and an Interrupt Hander or + -- an Entry was there. Wake it up and let it change + -- it place of waiting according to its new state. + + POP.Wakeup (Server_ID (Interrupt), + Interrupt_Server_Blocked_Interrupt_Sleep); + end if; + end Unblock_Interrupt; + + or + accept Ignore_Interrupt (Interrupt : Interrupt_ID) do + if Ignored (Interrupt) then + return; + end if; + + Ignored (Interrupt) := True; + + -- If there is a handler associated with the Interrupt, + -- detach it first. In this way we make sure that the + -- Server_Task is not on sigwait. This is legal since + -- Unignore_Interrupt is to install the default action. + + if User_Handler (Interrupt).H /= null then + Unprotected_Detach_Handler + (Interrupt => Interrupt, Static => True); + + elsif User_Entry (Interrupt).T /= Null_Task then + User_Entry (Interrupt) := Entry_Assoc' + (T => Null_Task, E => Null_Task_Entry); + Unbind_Handler (Interrupt); + end if; + + IMOP.Install_Ignore_Action (IMNG.Interrupt_ID (Interrupt)); + end Ignore_Interrupt; + + or + accept Unignore_Interrupt (Interrupt : Interrupt_ID) do + Ignored (Interrupt) := False; + + -- If there is a handler associated with the Interrupt, + -- detach it first. In this way we make sure that the + -- Server_Task is not on sigwait. This is legal since + -- Unignore_Interrupt is to install the default action. + + if User_Handler (Interrupt).H /= null then + Unprotected_Detach_Handler + (Interrupt => Interrupt, Static => True); + + elsif User_Entry (Interrupt).T /= Null_Task then + User_Entry (Interrupt) := Entry_Assoc' + (T => Null_Task, E => Null_Task_Entry); + Unbind_Handler (Interrupt); + end if; + + IMOP.Install_Default_Action (IMNG.Interrupt_ID (Interrupt)); + end Unignore_Interrupt; + end select; + + exception + -- If there is a program error we just want to propagate it to + -- the caller and do not want to stop this task. + + when Program_Error => + null; + + when others => + pragma Assert (False); + null; + end; + end loop; + end Interrupt_Manager; + + ----------------- + -- Server_Task -- + ----------------- + + task body Server_Task is + Intwait_Mask : aliased IMNG.Interrupt_Mask; + Ret_Interrupt : Interrupt_ID; + Self_ID : constant Task_Id := Self; + Tmp_Handler : Parameterless_Handler; + Tmp_ID : Task_Id; + Tmp_Entry_Index : Task_Entry_Index; + + begin + -- By making this task independent of master, when the process + -- goes away, the Server_Task will terminate gracefully. + + System.Tasking.Utilities.Make_Independent; + + -- Install default action in system level + + IMOP.Install_Default_Action (IMNG.Interrupt_ID (Interrupt)); + + -- Note: All tasks in RTS will have all the Reserve Interrupts being + -- masked (except the Interrupt_Manager) and Keep_Unmasked unmasked when + -- created. + + -- Abort_Task_Interrupt is one of the Interrupt unmasked in all tasks. + -- We mask the Interrupt in this particular task so that "sigwait" is + -- possible to catch an explicitly sent Abort_Task_Interrupt from the + -- Interrupt_Manager. + + -- There are two Interrupt interrupts that this task catch through + -- "sigwait." One is the Interrupt this task is designated to catch + -- in order to execute user handler or entry. The other one is the + -- Abort_Task_Interrupt. This interrupt is being sent from the + -- Interrupt_Manager to inform status changes (e.g: become Blocked, + -- Handler or Entry is to be detached). + + -- Prepare a mask to used for sigwait + + IMOP.Empty_Interrupt_Mask (Intwait_Mask'Access); + + IMOP.Add_To_Interrupt_Mask + (Intwait_Mask'Access, IMNG.Interrupt_ID (Interrupt)); + + IMOP.Add_To_Interrupt_Mask + (Intwait_Mask'Access, IMNG.Abort_Task_Interrupt); + + IMOP.Thread_Block_Interrupt + (IMNG.Abort_Task_Interrupt); + + PIO.Set_Interrupt_ID (IMNG.Interrupt_ID (Interrupt), Self_ID); + + loop + System.Tasking.Initialization.Defer_Abort (Self_ID); + + if Single_Lock then + POP.Lock_RTS; + end if; + + POP.Write_Lock (Self_ID); + + if User_Handler (Interrupt).H = null + and then User_Entry (Interrupt).T = Null_Task + then + -- No Interrupt binding. If there is an interrupt, + -- Interrupt_Manager will take default action. + + Self_ID.Common.State := Interrupt_Server_Blocked_Interrupt_Sleep; + POP.Sleep (Self_ID, Interrupt_Server_Idle_Sleep); + Self_ID.Common.State := Runnable; + + elsif Blocked (Interrupt) then + + -- Interrupt is blocked. Stay here, so we won't catch + -- the Interrupt. + + Self_ID.Common.State := Interrupt_Server_Blocked_Interrupt_Sleep; + POP.Sleep (Self_ID, Interrupt_Server_Blocked_Interrupt_Sleep); + Self_ID.Common.State := Runnable; + + else + -- A Handler or an Entry is installed. At this point all tasks + -- mask for the Interrupt is masked. Catch the Interrupt using + -- sigwait. + + -- This task may wake up from sigwait by receiving an interrupt + -- (Abort_Task_Interrupt) from the Interrupt_Manager for unbinding + -- a Procedure Handler or an Entry. Or it could be a wake up + -- from status change (Unblocked -> Blocked). If that is not + -- the case, we should execute the attached Procedure or Entry. + + Self_ID.Common.State := Interrupt_Server_Blocked_On_Event_Flag; + POP.Unlock (Self_ID); + + if Single_Lock then + POP.Unlock_RTS; + end if; + + -- Avoid race condition when terminating application and + -- System.Parameters.No_Abort is True. + + if Parameters.No_Abort and then Self_ID.Pending_Action then + Initialization.Do_Pending_Action (Self_ID); + end if; + + Ret_Interrupt := + Interrupt_ID (IMOP.Interrupt_Wait (Intwait_Mask'Access)); + Self_ID.Common.State := Runnable; + + if Ret_Interrupt = Interrupt_ID (IMNG.Abort_Task_Interrupt) then + + -- Inform the Interrupt_Manager of wakeup from above sigwait + + POP.Abort_Task (Interrupt_Manager_ID); + + if Single_Lock then + POP.Lock_RTS; + end if; + + POP.Write_Lock (Self_ID); + + else + if Single_Lock then + POP.Lock_RTS; + end if; + + POP.Write_Lock (Self_ID); + + if Ret_Interrupt /= Interrupt then + + -- On some systems (e.g. recent linux kernels), sigwait + -- may return unexpectedly (with errno set to EINTR). + + null; + + else + -- Even though we have received an Interrupt the status may + -- have changed already before we got the Self_ID lock above + -- Therefore we make sure a Handler or an Entry is still + -- there and make appropriate call. + + -- If there is no calls to make we need to regenerate the + -- Interrupt in order not to lose it. + + if User_Handler (Interrupt).H /= null then + Tmp_Handler := User_Handler (Interrupt).H; + + -- RTS calls should not be made with self being locked + + POP.Unlock (Self_ID); + + if Single_Lock then + POP.Unlock_RTS; + end if; + + Tmp_Handler.all; + + if Single_Lock then + POP.Lock_RTS; + end if; + + POP.Write_Lock (Self_ID); + + elsif User_Entry (Interrupt).T /= Null_Task then + Tmp_ID := User_Entry (Interrupt).T; + Tmp_Entry_Index := User_Entry (Interrupt).E; + + -- RTS calls should not be made with self being locked + + if Single_Lock then + POP.Unlock_RTS; + end if; + + POP.Unlock (Self_ID); + + System.Tasking.Rendezvous.Call_Simple + (Tmp_ID, Tmp_Entry_Index, System.Null_Address); + + POP.Write_Lock (Self_ID); + + if Single_Lock then + POP.Lock_RTS; + end if; + + else + -- This is a situation that this task wakes up receiving + -- an Interrupt and before it gets the lock the Interrupt + -- is blocked. We do not want to lose the interrupt in + -- this case so we regenerate the Interrupt to process + -- level. + + IMOP.Interrupt_Self_Process + (IMNG.Interrupt_ID (Interrupt)); + end if; + end if; + end if; + end if; + + POP.Unlock (Self_ID); + + if Single_Lock then + POP.Unlock_RTS; + end if; + + System.Tasking.Initialization.Undefer_Abort (Self_ID); + + if Self_ID.Pending_Action then + Initialization.Do_Pending_Action (Self_ID); + end if; + + -- Undefer abort here to allow a window for this task to be aborted + -- at the time of system shutdown. We also explicitly test for + -- Pending_Action in case System.Parameters.No_Abort is True. + + end loop; + end Server_Task; + +-- Elaboration code for package System.Interrupts + +begin + -- Get Interrupt_Manager's ID so that Abort_Interrupt can be sent + + Interrupt_Manager_ID := To_System (Interrupt_Manager'Identity); + + -- During the elaboration of this package body we want the RTS + -- to inherit the interrupt mask from the Environment Task. + + IMOP.Setup_Interrupt_Mask; + + -- The environment task should have gotten its mask from the enclosing + -- process during the RTS start up. (See processing in s-inmaop.adb). Pass + -- the Interrupt_Mask of the environment task to the Interrupt_Manager. + + -- Note: At this point we know that all tasks are masked for non-reserved + -- signals. Only the Interrupt_Manager will have masks set up differently + -- inheriting the original environment task's mask. + + Interrupt_Manager.Initialize (IMOP.Environment_Mask); +end System.Interrupts; |