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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . T A S K _ P R I M I T I V E S . O P E R A T I O N S --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2021, 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. --
-- --
------------------------------------------------------------------------------
-- This is a NT (native) version of this package
-- This package contains all the GNULL primitives that interface directly with
-- the underlying OS.
with Interfaces.C;
with Interfaces.C.Strings;
with System.Float_Control;
with System.Interrupt_Management;
with System.Multiprocessors;
with System.OS_Primitives;
with System.Task_Info;
with System.Tasking.Debug;
with System.Win32.Ext;
with System.Soft_Links;
-- We use System.Soft_Links instead of System.Tasking.Initialization because
-- the later is a higher level package that we shouldn't depend on. For
-- example when using the restricted run time, it is replaced by
-- System.Tasking.Restricted.Stages.
package body System.Task_Primitives.Operations is
package SSL renames System.Soft_Links;
use Interfaces.C;
use Interfaces.C.Strings;
use System.OS_Interface;
use System.OS_Primitives;
use System.Parameters;
use System.Task_Info;
use System.Tasking;
use System.Tasking.Debug;
use System.Win32;
use System.Win32.Ext;
pragma Link_With ("-Xlinker --stack=0x200000,0x1000");
-- Change the default stack size (2 MB) for tasking programs on Windows.
-- This allows about 1000 tasks running at the same time. Note that
-- we set the stack size for non tasking programs on System unit.
-- Also note that under Windows XP, we use a Windows XP extension to
-- specify the stack size on a per task basis, as done under other OSes.
---------------------
-- Local Functions --
---------------------
procedure InitializeCriticalSection (pCriticalSection : access RTS_Lock);
procedure InitializeCriticalSection
(pCriticalSection : access CRITICAL_SECTION);
pragma Import
(Stdcall, InitializeCriticalSection, "InitializeCriticalSection");
procedure EnterCriticalSection (pCriticalSection : access RTS_Lock);
procedure EnterCriticalSection
(pCriticalSection : access CRITICAL_SECTION);
pragma Import (Stdcall, EnterCriticalSection, "EnterCriticalSection");
procedure LeaveCriticalSection (pCriticalSection : access RTS_Lock);
procedure LeaveCriticalSection (pCriticalSection : access CRITICAL_SECTION);
pragma Import (Stdcall, LeaveCriticalSection, "LeaveCriticalSection");
procedure DeleteCriticalSection (pCriticalSection : access RTS_Lock);
procedure DeleteCriticalSection
(pCriticalSection : access CRITICAL_SECTION);
pragma Import (Stdcall, DeleteCriticalSection, "DeleteCriticalSection");
----------------
-- Local Data --
----------------
Environment_Task_Id : Task_Id;
-- A variable to hold Task_Id for the environment task
Single_RTS_Lock : aliased RTS_Lock;
-- This is a lock to allow only one thread of control in the RTS at
-- a time; it is used to execute in mutual exclusion from all other tasks.
-- Used to protect All_Tasks_List
Time_Slice_Val : Integer;
pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
Dispatching_Policy : Character;
pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
function Get_Policy (Prio : System.Any_Priority) return Character;
pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
-- Get priority specific dispatching policy
Foreign_Task_Elaborated : aliased Boolean := True;
-- Used to identified fake tasks (i.e., non-Ada Threads)
Null_Thread_Id : constant Thread_Id := 0;
-- Constant to indicate that the thread identifier has not yet been
-- initialized.
------------------------------------
-- The thread local storage index --
------------------------------------
TlsIndex : DWORD;
pragma Export (Ada, TlsIndex);
-- To ensure that this variable won't be local to this package, since
-- in some cases, inlining forces this variable to be global anyway.
--------------------
-- Local Packages --
--------------------
package Specific is
function Is_Valid_Task return Boolean;
pragma Inline (Is_Valid_Task);
-- Does executing thread have a TCB?
procedure Set (Self_Id : Task_Id);
pragma Inline (Set);
-- Set the self id for the current task
end Specific;
package body Specific is
-------------------
-- Is_Valid_Task --
-------------------
function Is_Valid_Task return Boolean is
begin
return TlsGetValue (TlsIndex) /= System.Null_Address;
end Is_Valid_Task;
---------
-- Set --
---------
procedure Set (Self_Id : Task_Id) is
Succeeded : BOOL;
begin
Succeeded := TlsSetValue (TlsIndex, To_Address (Self_Id));
pragma Assert (Succeeded = Win32.TRUE);
end Set;
end Specific;
----------------------------------
-- ATCB allocation/deallocation --
----------------------------------
package body ATCB_Allocation is separate;
-- The body of this package is shared across several targets
---------------------------------
-- Support for foreign threads --
---------------------------------
function Register_Foreign_Thread
(Thread : Thread_Id;
Sec_Stack_Size : Size_Type := Unspecified_Size) return Task_Id;
-- Allocate and initialize a new ATCB for the current Thread. The size of
-- the secondary stack can be optionally specified.
function Register_Foreign_Thread
(Thread : Thread_Id;
Sec_Stack_Size : Size_Type := Unspecified_Size)
return Task_Id is separate;
----------------------------------
-- Condition Variable Functions --
----------------------------------
procedure Initialize_Cond (Cond : not null access Condition_Variable);
-- Initialize given condition variable Cond
procedure Finalize_Cond (Cond : not null access Condition_Variable);
-- Finalize given condition variable Cond
procedure Cond_Signal (Cond : not null access Condition_Variable);
-- Signal condition variable Cond
procedure Cond_Wait
(Cond : not null access Condition_Variable;
L : not null access RTS_Lock);
-- Wait on conditional variable Cond, using lock L
procedure Cond_Timed_Wait
(Cond : not null access Condition_Variable;
L : not null access RTS_Lock;
Rel_Time : Duration;
Timed_Out : out Boolean;
Status : out Integer);
-- Do timed wait on condition variable Cond using lock L. The duration
-- of the timed wait is given by Rel_Time. When the condition is
-- signalled, Timed_Out shows whether or not a time out occurred.
-- Status is only valid if Timed_Out is False, in which case it
-- shows whether Cond_Timed_Wait completed successfully.
---------------------
-- Initialize_Cond --
---------------------
procedure Initialize_Cond (Cond : not null access Condition_Variable) is
hEvent : HANDLE;
begin
hEvent := CreateEvent (null, Win32.TRUE, Win32.FALSE, Null_Ptr);
pragma Assert (hEvent /= 0);
Cond.all := Condition_Variable (hEvent);
end Initialize_Cond;
-------------------
-- Finalize_Cond --
-------------------
-- No such problem here, DosCloseEventSem has been derived.
-- What does such refer to in above comment???
procedure Finalize_Cond (Cond : not null access Condition_Variable) is
Result : BOOL;
begin
Result := CloseHandle (HANDLE (Cond.all));
pragma Assert (Result = Win32.TRUE);
end Finalize_Cond;
-----------------
-- Cond_Signal --
-----------------
procedure Cond_Signal (Cond : not null access Condition_Variable) is
Result : BOOL;
begin
Result := SetEvent (HANDLE (Cond.all));
pragma Assert (Result = Win32.TRUE);
end Cond_Signal;
---------------
-- Cond_Wait --
---------------
-- Pre-condition: Cond is posted
-- L is locked.
-- Post-condition: Cond is posted
-- L is locked.
procedure Cond_Wait
(Cond : not null access Condition_Variable;
L : not null access RTS_Lock)
is
Result : DWORD;
Result_Bool : BOOL;
begin
-- Must reset Cond BEFORE L is unlocked
Result_Bool := ResetEvent (HANDLE (Cond.all));
pragma Assert (Result_Bool = Win32.TRUE);
Unlock (L);
-- No problem if we are interrupted here: if the condition is signaled,
-- WaitForSingleObject will simply not block
Result := WaitForSingleObject (HANDLE (Cond.all), Wait_Infinite);
pragma Assert (Result = 0);
Write_Lock (L);
end Cond_Wait;
---------------------
-- Cond_Timed_Wait --
---------------------
-- Pre-condition: Cond is posted
-- L is locked.
-- Post-condition: Cond is posted
-- L is locked.
procedure Cond_Timed_Wait
(Cond : not null access Condition_Variable;
L : not null access RTS_Lock;
Rel_Time : Duration;
Timed_Out : out Boolean;
Status : out Integer)
is
Time_Out_Max : constant DWORD := 16#FFFF0000#;
-- NT 4 can't handle excessive timeout values (e.g. DWORD'Last - 1)
Time_Out : DWORD;
Result : BOOL;
Wait_Result : DWORD;
begin
-- Must reset Cond BEFORE L is unlocked
Result := ResetEvent (HANDLE (Cond.all));
pragma Assert (Result = Win32.TRUE);
Unlock (L);
-- No problem if we are interrupted here: if the condition is signaled,
-- WaitForSingleObject will simply not block.
if Rel_Time <= 0.0 then
Timed_Out := True;
Wait_Result := 0;
else
Time_Out :=
(if Rel_Time >= Duration (Time_Out_Max) / 1000
then Time_Out_Max
else DWORD (Rel_Time * 1000));
Wait_Result := WaitForSingleObject (HANDLE (Cond.all), Time_Out);
if Wait_Result = WAIT_TIMEOUT then
Timed_Out := True;
Wait_Result := 0;
else
Timed_Out := False;
end if;
end if;
Write_Lock (L);
-- Ensure post-condition
if Timed_Out then
Result := SetEvent (HANDLE (Cond.all));
pragma Assert (Result = Win32.TRUE);
end if;
Status := Integer (Wait_Result);
end Cond_Timed_Wait;
------------------
-- Stack_Guard --
------------------
-- The underlying thread system sets a guard page at the bottom of a thread
-- stack, so nothing is needed.
-- ??? Check the comment above
procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
pragma Unreferenced (T, On);
begin
null;
end Stack_Guard;
--------------------
-- Get_Thread_Id --
--------------------
function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
begin
return T.Common.LL.Thread;
end Get_Thread_Id;
----------
-- Self --
----------
function Self return Task_Id is
Self_Id : constant Task_Id := To_Task_Id (TlsGetValue (TlsIndex));
begin
if Self_Id = null then
return Register_Foreign_Thread (GetCurrentThread);
else
return Self_Id;
end if;
end Self;
---------------------
-- Initialize_Lock --
---------------------
-- Note: mutexes and cond_variables needed per-task basis are initialized
-- in Initialize_TCB and the Storage_Error is handled. Other mutexes (such
-- as RTS_Lock, Memory_Lock...) used in the RTS is initialized before any
-- status change of RTS. Therefore raising Storage_Error in the following
-- routines should be able to be handled safely.
procedure Initialize_Lock
(Prio : System.Any_Priority;
L : not null access Lock)
is
begin
InitializeCriticalSection (L.Mutex'Access);
L.Owner_Priority := 0;
L.Priority := Prio;
end Initialize_Lock;
procedure Initialize_Lock
(L : not null access RTS_Lock; Level : Lock_Level)
is
pragma Unreferenced (Level);
begin
InitializeCriticalSection (L);
end Initialize_Lock;
-------------------
-- Finalize_Lock --
-------------------
procedure Finalize_Lock (L : not null access Lock) is
begin
DeleteCriticalSection (L.Mutex'Access);
end Finalize_Lock;
procedure Finalize_Lock (L : not null access RTS_Lock) is
begin
DeleteCriticalSection (L);
end Finalize_Lock;
----------------
-- Write_Lock --
----------------
procedure Write_Lock
(L : not null access Lock; Ceiling_Violation : out Boolean) is
begin
L.Owner_Priority := Get_Priority (Self);
if L.Priority < L.Owner_Priority then
Ceiling_Violation := True;
return;
end if;
EnterCriticalSection (L.Mutex'Access);
Ceiling_Violation := False;
end Write_Lock;
procedure Write_Lock (L : not null access RTS_Lock) is
begin
EnterCriticalSection (L);
end Write_Lock;
procedure Write_Lock (T : Task_Id) is
begin
EnterCriticalSection (T.Common.LL.L'Access);
end Write_Lock;
---------------
-- Read_Lock --
---------------
procedure Read_Lock
(L : not null access Lock; Ceiling_Violation : out Boolean) is
begin
Write_Lock (L, Ceiling_Violation);
end Read_Lock;
------------
-- Unlock --
------------
procedure Unlock (L : not null access Lock) is
begin
LeaveCriticalSection (L.Mutex'Access);
end Unlock;
procedure Unlock (L : not null access RTS_Lock) is
begin
LeaveCriticalSection (L);
end Unlock;
procedure Unlock (T : Task_Id) is
begin
LeaveCriticalSection (T.Common.LL.L'Access);
end Unlock;
-----------------
-- Set_Ceiling --
-----------------
-- Dynamic priority ceilings are not supported by the underlying system
procedure Set_Ceiling
(L : not null access Lock;
Prio : System.Any_Priority)
is
pragma Unreferenced (L, Prio);
begin
null;
end Set_Ceiling;
-----------
-- Sleep --
-----------
procedure Sleep
(Self_ID : Task_Id;
Reason : System.Tasking.Task_States)
is
pragma Unreferenced (Reason);
begin
pragma Assert (Self_ID = Self);
Cond_Wait (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L'Access);
if Self_ID.Deferral_Level = 0
and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
then
Unlock (Self_ID);
raise Standard'Abort_Signal;
end if;
end Sleep;
-----------------
-- Timed_Sleep --
-----------------
-- This is for use within the run-time system, so abort is assumed to be
-- already deferred, and the caller should be holding its own ATCB lock.
procedure Timed_Sleep
(Self_ID : Task_Id;
Time : Duration;
Mode : ST.Delay_Modes;
Reason : System.Tasking.Task_States;
Timedout : out Boolean;
Yielded : out Boolean)
is
pragma Unreferenced (Reason);
Check_Time : Duration := Monotonic_Clock;
Rel_Time : Duration;
Abs_Time : Duration;
Result : Integer;
pragma Unreferenced (Result);
Local_Timedout : Boolean;
begin
Timedout := True;
Yielded := False;
if Mode = Relative then
Rel_Time := Time;
Abs_Time := Duration'Min (Time, Max_Sensible_Delay) + Check_Time;
else
Rel_Time := Time - Check_Time;
Abs_Time := Time;
end if;
if Rel_Time > 0.0 then
loop
exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
Cond_Timed_Wait
(Self_ID.Common.LL.CV'Access,
Self_ID.Common.LL.L'Access,
Rel_Time, Local_Timedout, Result);
Check_Time := Monotonic_Clock;
exit when Abs_Time <= Check_Time;
if not Local_Timedout then
-- Somebody may have called Wakeup for us
Timedout := False;
exit;
end if;
Rel_Time := Abs_Time - Check_Time;
end loop;
end if;
end Timed_Sleep;
-----------------
-- Timed_Delay --
-----------------
procedure Timed_Delay
(Self_ID : Task_Id;
Time : Duration;
Mode : ST.Delay_Modes)
is
Check_Time : Duration := Monotonic_Clock;
Rel_Time : Duration;
Abs_Time : Duration;
Timedout : Boolean;
Result : Integer;
pragma Unreferenced (Timedout, Result);
begin
Write_Lock (Self_ID);
if Mode = Relative then
Rel_Time := Time;
Abs_Time := Time + Check_Time;
else
Rel_Time := Time - Check_Time;
Abs_Time := Time;
end if;
if Rel_Time > 0.0 then
Self_ID.Common.State := Delay_Sleep;
loop
exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
Cond_Timed_Wait
(Self_ID.Common.LL.CV'Access,
Self_ID.Common.LL.L'Access,
Rel_Time, Timedout, Result);
Check_Time := Monotonic_Clock;
exit when Abs_Time <= Check_Time;
Rel_Time := Abs_Time - Check_Time;
end loop;
Self_ID.Common.State := Runnable;
end if;
Unlock (Self_ID);
Yield;
end Timed_Delay;
------------
-- Wakeup --
------------
procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
pragma Unreferenced (Reason);
begin
Cond_Signal (T.Common.LL.CV'Access);
end Wakeup;
-----------
-- Yield --
-----------
procedure Yield (Do_Yield : Boolean := True) is
begin
-- Note: in a previous implementation if Do_Yield was False, then we
-- introduced a delay of 1 millisecond in an attempt to get closer to
-- annex D semantics, and in particular to make ACATS CXD8002 pass. But
-- this change introduced a huge performance regression evaluating the
-- Count attribute. So we decided to remove this processing.
-- Moreover, CXD8002 appears to pass on Windows (although we do not
-- guarantee full Annex D compliance on Windows in any case).
if Do_Yield then
SwitchToThread;
end if;
end Yield;
------------------
-- Set_Priority --
------------------
procedure Set_Priority
(T : Task_Id;
Prio : System.Any_Priority;
Loss_Of_Inheritance : Boolean := False)
is
Res : BOOL;
pragma Unreferenced (Loss_Of_Inheritance);
begin
Res :=
SetThreadPriority
(T.Common.LL.Thread,
Interfaces.C.int (Underlying_Priorities (Prio)));
pragma Assert (Res = Win32.TRUE);
-- Note: Annex D (RM D.2.3(5/2)) requires the task to be placed at the
-- head of its priority queue when decreasing its priority as a result
-- of a loss of inherited priority. This is not the case, but we
-- consider it an acceptable variation (RM 1.1.3(6)), given this is
-- the built-in behavior offered by the Windows operating system.
-- In older versions we attempted to better approximate the Annex D
-- required behavior, but this simulation was not entirely accurate,
-- and it seems better to live with the standard Windows semantics.
T.Common.Current_Priority := Prio;
end Set_Priority;
------------------
-- Get_Priority --
------------------
function Get_Priority (T : Task_Id) return System.Any_Priority is
begin
return T.Common.Current_Priority;
end Get_Priority;
----------------
-- Enter_Task --
----------------
-- There were two paths were we needed to call Enter_Task :
-- 1) from System.Task_Primitives.Operations.Initialize
-- 2) from System.Tasking.Stages.Task_Wrapper
-- The pseudo handle (LL.Thread) need not be closed when it is no
-- longer needed. Calling the CloseHandle function with this handle
-- has no effect.
procedure Enter_Task (Self_ID : Task_Id) is
procedure Get_Stack_Bounds (Base : Address; Limit : Address);
pragma Import (C, Get_Stack_Bounds, "__gnat_get_stack_bounds");
-- Get stack boundaries
begin
Specific.Set (Self_ID);
-- Properly initializes the FPU for x86 systems
System.Float_Control.Reset;
if Self_ID.Common.Task_Info /= null
and then
Self_ID.Common.Task_Info.CPU >= CPU_Number (Number_Of_Processors)
then
raise Invalid_CPU_Number;
end if;
-- Initialize the thread here only if not set. This is done for a
-- foreign task but is not needed when a real thread-id is already
-- set in Create_Task. Note that we do want to keep the real thread-id
-- as it is the only way to free the associated resource. Another way
-- to say this is that a pseudo thread-id from a foreign thread won't
-- allow for freeing resources.
if Self_ID.Common.LL.Thread = Null_Thread_Id then
Self_ID.Common.LL.Thread := GetCurrentThread;
end if;
Self_ID.Common.LL.Thread_Id := GetCurrentThreadId;
Get_Stack_Bounds
(Self_ID.Common.Compiler_Data.Pri_Stack_Info.Base'Address,
Self_ID.Common.Compiler_Data.Pri_Stack_Info.Limit'Address);
end Enter_Task;
-------------------
-- Is_Valid_Task --
-------------------
function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
-----------------------------
-- Register_Foreign_Thread --
-----------------------------
function Register_Foreign_Thread return Task_Id is
begin
if Is_Valid_Task then
return Self;
else
return Register_Foreign_Thread (GetCurrentThread);
end if;
end Register_Foreign_Thread;
--------------------
-- Initialize_TCB --
--------------------
procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
begin
-- Initialize thread ID to 0, this is needed to detect threads that
-- are not yet activated.
Self_ID.Common.LL.Thread := Null_Thread_Id;
Initialize_Cond (Self_ID.Common.LL.CV'Access);
Initialize_Lock (Self_ID.Common.LL.L'Access, ATCB_Level);
Succeeded := True;
end Initialize_TCB;
-----------------
-- Create_Task --
-----------------
procedure Create_Task
(T : Task_Id;
Wrapper : System.Address;
Stack_Size : System.Parameters.Size_Type;
Priority : System.Any_Priority;
Succeeded : out Boolean)
is
Initial_Stack_Size : constant := 1024;
-- We set the initial stack size to 1024. On Windows version prior to XP
-- there is no way to fix a task stack size. Only the initial stack size
-- can be set, the operating system will raise the task stack size if
-- needed.
function Is_Windows_XP return Integer;
pragma Import (C, Is_Windows_XP, "__gnat_is_windows_xp");
-- Returns 1 if running on Windows XP
hTask : HANDLE;
TaskId : aliased DWORD;
pTaskParameter : Win32.PVOID;
Result : DWORD;
Entry_Point : PTHREAD_START_ROUTINE;
use type System.Multiprocessors.CPU_Range;
begin
-- Check whether both Dispatching_Domain and CPU are specified for the
-- task, and the CPU value is not contained within the range of
-- processors for the domain.
if T.Common.Domain /= null
and then T.Common.Base_CPU /= System.Multiprocessors.Not_A_Specific_CPU
and then
(T.Common.Base_CPU not in T.Common.Domain'Range
or else not T.Common.Domain (T.Common.Base_CPU))
then
Succeeded := False;
return;
end if;
pTaskParameter := To_Address (T);
Entry_Point := To_PTHREAD_START_ROUTINE (Wrapper);
if Is_Windows_XP = 1 then
hTask := CreateThread
(null,
DWORD (Stack_Size),
Entry_Point,
pTaskParameter,
DWORD (Create_Suspended)
or DWORD (Stack_Size_Param_Is_A_Reservation),
TaskId'Unchecked_Access);
else
hTask := CreateThread
(null,
Initial_Stack_Size,
Entry_Point,
pTaskParameter,
DWORD (Create_Suspended),
TaskId'Unchecked_Access);
end if;
-- Step 1: Create the thread in blocked mode
if hTask = 0 then
Succeeded := False;
return;
end if;
-- Step 2: set its TCB
T.Common.LL.Thread := hTask;
-- Note: it would be useful to initialize Thread_Id right away to avoid
-- a race condition in gdb where Thread_ID may not have the right value
-- yet, but GetThreadId is a Vista specific API, not available under XP:
-- T.Common.LL.Thread_Id := GetThreadId (hTask); so instead we set the
-- field to 0 to avoid having a random value. Thread_Id is initialized
-- in Enter_Task anyway.
T.Common.LL.Thread_Id := 0;
-- Step 3: set its priority (child has inherited priority from parent)
Set_Priority (T, Priority);
if Time_Slice_Val = 0
or else Dispatching_Policy = 'F'
or else Get_Policy (Priority) = 'F'
then
-- Here we need Annex D semantics so we disable the NT priority
-- boost. A priority boost is temporarily given by the system to
-- a thread when it is taken out of a wait state.
SetThreadPriorityBoost (hTask, DisablePriorityBoost => Win32.TRUE);
end if;
-- Step 4: Handle pragma CPU and Task_Info
Set_Task_Affinity (T);
-- Step 5: Now, start it for good
Result := ResumeThread (hTask);
pragma Assert (Result = 1);
Succeeded := Result = 1;
end Create_Task;
------------------
-- Finalize_TCB --
------------------
procedure Finalize_TCB (T : Task_Id) is
Succeeded : BOOL;
pragma Unreferenced (Succeeded);
begin
Finalize_Lock (T.Common.LL.L'Access);
Finalize_Cond (T.Common.LL.CV'Access);
if T.Known_Tasks_Index /= -1 then
Known_Tasks (T.Known_Tasks_Index) := null;
end if;
if T.Common.LL.Thread /= Null_Thread_Id then
-- This task has been activated. Close the thread handle. This
-- is needed to release system resources.
Succeeded := CloseHandle (T.Common.LL.Thread);
-- Note that we do not check for the returned value, this is
-- because the above call will fail for a foreign thread. But
-- we still need to call it to properly close Ada tasks created
-- with CreateThread() in Create_Task above.
end if;
ATCB_Allocation.Free_ATCB (T);
end Finalize_TCB;
---------------
-- Exit_Task --
---------------
procedure Exit_Task is
begin
Specific.Set (null);
end Exit_Task;
----------------
-- Abort_Task --
----------------
procedure Abort_Task (T : Task_Id) is
pragma Unreferenced (T);
begin
null;
end Abort_Task;
----------------------
-- Environment_Task --
----------------------
function Environment_Task return Task_Id is
begin
return Environment_Task_Id;
end Environment_Task;
--------------
-- Lock_RTS --
--------------
procedure Lock_RTS is
begin
Write_Lock (Single_RTS_Lock'Access);
end Lock_RTS;
----------------
-- Unlock_RTS --
----------------
procedure Unlock_RTS is
begin
Unlock (Single_RTS_Lock'Access);
end Unlock_RTS;
----------------
-- Initialize --
----------------
procedure Initialize (Environment_Task : Task_Id) is
Discard : BOOL;
begin
Environment_Task_Id := Environment_Task;
OS_Primitives.Initialize;
Interrupt_Management.Initialize;
if Time_Slice_Val = 0 or else Dispatching_Policy = 'F' then
-- Here we need Annex D semantics, switch the current process to the
-- Realtime_Priority_Class.
Discard := OS_Interface.SetPriorityClass
(GetCurrentProcess, Realtime_Priority_Class);
end if;
TlsIndex := TlsAlloc;
-- Initialize the lock used to synchronize chain of all ATCBs
Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
Environment_Task.Common.LL.Thread := GetCurrentThread;
-- Make environment task known here because it doesn't go through
-- Activate_Tasks, which does it for all other tasks.
Known_Tasks (Known_Tasks'First) := Environment_Task;
Environment_Task.Known_Tasks_Index := Known_Tasks'First;
Enter_Task (Environment_Task);
-- pragma CPU and dispatching domains for the environment task
Set_Task_Affinity (Environment_Task);
end Initialize;
---------------------
-- Monotonic_Clock --
---------------------
function Monotonic_Clock return Duration is
function Internal_Clock return Duration;
pragma Import (Ada, Internal_Clock, "__gnat_monotonic_clock");
begin
return Internal_Clock;
end Monotonic_Clock;
-------------------
-- RT_Resolution --
-------------------
function RT_Resolution return Duration is
Ticks_Per_Second : aliased LARGE_INTEGER;
begin
QueryPerformanceFrequency (Ticks_Per_Second'Access);
return Duration (1.0 / Ticks_Per_Second);
end RT_Resolution;
----------------
-- Initialize --
----------------
procedure Initialize (S : in out Suspension_Object) is
begin
-- Initialize internal state. It is always initialized to False (ARM
-- D.10 par. 6).
S.State := False;
S.Waiting := False;
-- Initialize internal mutex
InitializeCriticalSection (S.L'Access);
-- Initialize internal condition variable
S.CV := CreateEvent (null, Win32.TRUE, Win32.FALSE, Null_Ptr);
pragma Assert (S.CV /= 0);
end Initialize;
--------------
-- Finalize --
--------------
procedure Finalize (S : in out Suspension_Object) is
Result : BOOL;
begin
-- Destroy internal mutex
DeleteCriticalSection (S.L'Access);
-- Destroy internal condition variable
Result := CloseHandle (S.CV);
pragma Assert (Result = Win32.TRUE);
end Finalize;
-------------------
-- Current_State --
-------------------
function Current_State (S : Suspension_Object) return Boolean is
begin
-- We do not want to use lock on this read operation. State is marked
-- as Atomic so that we ensure that the value retrieved is correct.
return S.State;
end Current_State;
---------------
-- Set_False --
---------------
procedure Set_False (S : in out Suspension_Object) is
begin
SSL.Abort_Defer.all;
EnterCriticalSection (S.L'Access);
S.State := False;
LeaveCriticalSection (S.L'Access);
SSL.Abort_Undefer.all;
end Set_False;
--------------
-- Set_True --
--------------
procedure Set_True (S : in out Suspension_Object) is
Result : BOOL;
begin
SSL.Abort_Defer.all;
EnterCriticalSection (S.L'Access);
-- If there is already a task waiting on this suspension object then
-- we resume it, leaving the state of the suspension object to False,
-- as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
-- the state to True.
if S.Waiting then
S.Waiting := False;
S.State := False;
Result := SetEvent (S.CV);
pragma Assert (Result = Win32.TRUE);
else
S.State := True;
end if;
LeaveCriticalSection (S.L'Access);
SSL.Abort_Undefer.all;
end Set_True;
------------------------
-- Suspend_Until_True --
------------------------
procedure Suspend_Until_True (S : in out Suspension_Object) is
Result : DWORD;
Result_Bool : BOOL;
begin
SSL.Abort_Defer.all;
EnterCriticalSection (S.L'Access);
if S.Waiting then
-- Program_Error must be raised upon calling Suspend_Until_True
-- if another task is already waiting on that suspension object
-- (ARM D.10 par. 10).
LeaveCriticalSection (S.L'Access);
SSL.Abort_Undefer.all;
raise Program_Error;
else
-- Suspend the task if the state is False. Otherwise, the task
-- continues its execution, and the state of the suspension object
-- is set to False (ARM D.10 par. 9).
if S.State then
S.State := False;
LeaveCriticalSection (S.L'Access);
SSL.Abort_Undefer.all;
else
S.Waiting := True;
-- Must reset CV BEFORE L is unlocked
Result_Bool := ResetEvent (S.CV);
pragma Assert (Result_Bool = Win32.TRUE);
LeaveCriticalSection (S.L'Access);
SSL.Abort_Undefer.all;
Result := WaitForSingleObject (S.CV, Wait_Infinite);
pragma Assert (Result = 0);
end if;
end if;
end Suspend_Until_True;
----------------
-- Check_Exit --
----------------
-- Dummy versions, currently this only works for solaris (native)
function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
pragma Unreferenced (Self_ID);
begin
return True;
end Check_Exit;
--------------------
-- Check_No_Locks --
--------------------
function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
pragma Unreferenced (Self_ID);
begin
return True;
end Check_No_Locks;
------------------
-- Suspend_Task --
------------------
function Suspend_Task
(T : ST.Task_Id;
Thread_Self : Thread_Id) return Boolean
is
begin
if T.Common.LL.Thread /= Thread_Self then
return SuspendThread (T.Common.LL.Thread) = NO_ERROR;
else
return True;
end if;
end Suspend_Task;
-----------------
-- Resume_Task --
-----------------
function Resume_Task
(T : ST.Task_Id;
Thread_Self : Thread_Id) return Boolean
is
begin
if T.Common.LL.Thread /= Thread_Self then
return ResumeThread (T.Common.LL.Thread) = NO_ERROR;
else
return True;
end if;
end Resume_Task;
--------------------
-- Stop_All_Tasks --
--------------------
procedure Stop_All_Tasks is
begin
null;
end Stop_All_Tasks;
---------------
-- Stop_Task --
---------------
function Stop_Task (T : ST.Task_Id) return Boolean is
pragma Unreferenced (T);
begin
return False;
end Stop_Task;
-------------------
-- Continue_Task --
-------------------
function Continue_Task (T : ST.Task_Id) return Boolean is
pragma Unreferenced (T);
begin
return False;
end Continue_Task;
-----------------------
-- Set_Task_Affinity --
-----------------------
procedure Set_Task_Affinity (T : ST.Task_Id) is
Result : DWORD;
use type System.Multiprocessors.CPU_Range;
begin
-- Do nothing if the underlying thread has not yet been created. If the
-- thread has not yet been created then the proper affinity will be set
-- during its creation.
if T.Common.LL.Thread = Null_Thread_Id then
null;
-- pragma CPU
elsif T.Common.Base_CPU /= Multiprocessors.Not_A_Specific_CPU then
-- The CPU numbering in pragma CPU starts at 1 while the subprogram
-- to set the affinity starts at 0, therefore we must substract 1.
Result :=
SetThreadIdealProcessor
(T.Common.LL.Thread, ProcessorId (T.Common.Base_CPU) - 1);
pragma Assert (Result = 1);
-- Task_Info
elsif T.Common.Task_Info /= null then
if T.Common.Task_Info.CPU /= Task_Info.Any_CPU then
Result :=
SetThreadIdealProcessor
(T.Common.LL.Thread, T.Common.Task_Info.CPU);
pragma Assert (Result = 1);
end if;
-- Dispatching domains
elsif T.Common.Domain /= null
and then (T.Common.Domain /= ST.System_Domain
or else
T.Common.Domain.all /=
(Multiprocessors.CPU'First ..
Multiprocessors.Number_Of_CPUs => True))
then
declare
CPU_Set : DWORD := 0;
begin
for Proc in T.Common.Domain'Range loop
if T.Common.Domain (Proc) then
-- The thread affinity mask is a bit vector in which each
-- bit represents a logical processor.
CPU_Set := CPU_Set + 2 ** (Integer (Proc) - 1);
end if;
end loop;
Result := SetThreadAffinityMask (T.Common.LL.Thread, CPU_Set);
pragma Assert (Result = 1);
end;
end if;
end Set_Task_Affinity;
end System.Task_Primitives.Operations;