------------------------------------------------------------------------------
-- --
--- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
+-- 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) 1992-2004, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2006, 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- --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNARL; see file COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
+-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
+-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- Signal_ID
-- Initialize_Interrupts
-with System.Soft_Links;
--- used for Defer/Undefer_Abort
-
--- Note that we do not use System.Tasking.Initialization directly since
--- this 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.Initialization
-
-with System.OS_Interface;
--- used for various type, constant, and operations
-
-with System.Parameters;
--- used for Size_Type
+with Interfaces.C;
-with System.Tasking;
--- used for Ada_Task_Control_Block
--- Task_Id
--- ATCB components and types
+with System.Soft_Links;
+-- used for Abort_Defer/Undefer
-with Interfaces.C;
+-- 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.
with Unchecked_Conversion;
with Unchecked_Deallocation;
package body System.Task_Primitives.Operations is
+ package SSL renames System.Soft_Links;
+
use System.Tasking.Debug;
use System.Tasking;
use System.OS_Interface;
use System.Parameters;
use type Interfaces.C.int;
- package SSL renames System.Soft_Links;
-
subtype int is System.OS_Interface.int;
Relative : constant := 0;
-- Local Data --
----------------
- -- The followings are logically constants, but need to be initialized
- -- at run time.
+ -- The followings are logically constants, but need to be initialized at
+ -- run time.
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.
+ -- 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 mainly in Single_Lock mode, but also to protect All_Tasks_List
- ATCB_Key : aliased System.Address := System.Null_Address;
- -- Key used to find the Ada Task_Id associated with a thread
-
- ATCB_Key_Addr : System.Address := ATCB_Key'Address;
- pragma Export (Ada, ATCB_Key_Addr, "__gnat_ATCB_key_addr");
- -- Exported to support the temporary AE653 task registration
- -- implementation. This mechanism is used to minimize impact on other
- -- targets.
-
Environment_Task_Id : Task_Id;
- -- A variable to hold Task_Id for the environment task.
+ -- A variable to hold Task_Id for the environment task
Unblocked_Signal_Mask : aliased sigset_t;
-- The set of signals that should unblocked in all tasks
- -- The followings are internal configuration constants needed.
+ -- The followings are internal configuration constants needed
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");
- FIFO_Within_Priorities : constant Boolean := Dispatching_Policy = 'F';
- -- Indicates whether FIFO_Within_Priorities is set.
-
Mutex_Protocol : Priority_Type;
Foreign_Task_Elaborated : aliased Boolean := True;
- -- Used to identified fake tasks (i.e., non-Ada Threads).
+ -- Used to identified fake tasks (i.e., non-Ada Threads)
--------------------
-- Local Packages --
package Specific is
+ procedure Initialize;
+ pragma Inline (Initialize);
+ -- Initialize task specific data
+
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.
+ -- Set the self id for the current task
+
+ procedure Delete;
+ pragma Inline (Delete);
+ -- Delete the task specific data associated with the current task
function Self return Task_Id;
pragma Inline (Self);
- -- Return a pointer to the Ada Task Control Block of the calling task.
+ -- Return a pointer to the Ada Task Control Block of the calling task
end Specific;
package body Specific is separate;
- -- The body of this package is target specific.
+ -- The body of this package is target specific
---------------------------------
-- Support for foreign threads --
---------------------------------
function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
- -- Allocate and Initialize a new ATCB for the current Thread.
+ -- Allocate and Initialize a new ATCB for the current Thread
function Register_Foreign_Thread
(Thread : Thread_Id) return Task_Id is separate;
-----------------------
procedure Abort_Handler (signo : Signal);
- -- Handler for the abort (SIGABRT) signal to handle asynchronous abortion.
+ -- Handler for the abort (SIGABRT) signal to handle asynchronous abort
procedure Install_Signal_Handlers;
-- Install the default signal handlers for the current task
procedure Finalize_Lock (L : access Lock) is
Result : int;
-
begin
Result := semDelete (L.Mutex);
pragma Assert (Result = 0);
procedure Finalize_Lock (L : access RTS_Lock) is
Result : int;
-
begin
Result := semDelete (L.Mutex);
pragma Assert (Result = 0);
procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
Result : int;
-
begin
if L.Protocol = Prio_Protect
and then int (Self.Common.Current_Priority) > L.Prio_Ceiling
Global_Lock : Boolean := False)
is
Result : int;
-
begin
if not Single_Lock or else Global_Lock then
Result := semTake (L.Mutex, WAIT_FOREVER);
procedure Write_Lock (T : Task_Id) is
Result : int;
-
begin
if not Single_Lock then
Result := semTake (T.Common.LL.L.Mutex, WAIT_FOREVER);
------------
procedure Unlock (L : access Lock) is
- Result : int;
-
+ Result : int;
begin
Result := semGive (L.Mutex);
pragma Assert (Result = 0);
procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
Result : int;
-
begin
if not Single_Lock or else Global_Lock then
Result := semGive (L.Mutex);
procedure Unlock (T : Task_Id) is
Result : int;
-
begin
if not Single_Lock then
Result := semGive (T.Common.LL.L.Mutex);
begin
pragma Assert (Self_ID = Self);
- -- Release the mutex before sleeping.
+ -- Release the mutex before sleeping
+
if Single_Lock then
Result := semGive (Single_RTS_Lock.Mutex);
else
pragma Assert (Result = 0);
- -- Perform a blocking operation to take the CV semaphore.
- -- Note that a blocking operation in VxWorks will reenable
- -- task scheduling. When we are no longer blocked and control
- -- is returned, task scheduling will again be disabled.
+ -- Perform a blocking operation to take the CV semaphore. Note that a
+ -- blocking operation in VxWorks will reenable task scheduling. When we
+ -- are no longer blocked and control is returned, task scheduling will
+ -- again be disabled.
Result := semTake (Self_ID.Common.LL.CV, WAIT_FOREVER);
pragma Assert (Result = 0);
- -- Take the mutex back.
+ -- Take the mutex back
+
if Single_Lock then
Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER);
else
-- 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.
+ -- 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;
if Mode = Relative then
Absolute := Orig + Time;
- -- Systematically add one since the first tick will delay
- -- *at most* 1 / Rate_Duration seconds, so we need to add one to
- -- be on the safe side.
+ -- Systematically add one since the first tick will delay *at most*
+ -- 1 / Rate_Duration seconds, so we need to add one to be on the
+ -- safe side.
Ticks := To_Clock_Ticks (Time);
if Ticks > 0 then
loop
- -- Release the mutex before sleeping.
+ -- Release the mutex before sleeping
+
if Single_Lock then
Result := semGive (Single_RTS_Lock.Mutex);
else
pragma Assert (Result = 0);
- -- Perform a blocking operation to take the CV semaphore.
- -- Note that a blocking operation in VxWorks will reenable
- -- task scheduling. When we are no longer blocked and control
- -- is returned, task scheduling will again be disabled.
+ -- Perform a blocking operation to take the CV semaphore. Note
+ -- that a blocking operation in VxWorks will reenable task
+ -- scheduling. When we are no longer blocked and control is
+ -- returned, task scheduling will again be disabled.
Result := semTake (Self_ID.Common.LL.CV, Ticks);
if Result = 0 then
+
-- Somebody may have called Wakeup for us
Wakeup := True;
else
if errno /= S_objLib_OBJ_TIMEOUT then
Wakeup := True;
+
else
- -- If Ticks = int'last, it was most probably truncated
- -- so let's make another round after recomputing Ticks
- -- from the the absolute time.
+ -- If Ticks = int'last, it was most probably truncated so
+ -- let's make another round after recomputing Ticks from
+ -- the the absolute time.
if Ticks /= int'Last then
Timedout := True;
end if;
end if;
- -- Take the mutex back.
+ -- Take the mutex back
+
if Single_Lock then
Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER);
else
else
Timedout := True;
- -- Should never hold a lock while yielding.
+ -- Should never hold a lock while yielding
+
if Single_Lock then
Result := semGive (Single_RTS_Lock.Mutex);
taskDelay (0);
-- Timed_Delay --
-----------------
- -- This is for use in implementing delay statements, so
- -- we assume the caller is holding no locks.
+ -- This is for use in implementing delay statements, so we assume the
+ -- caller is holding no locks.
procedure Timed_Delay
- (Self_ID : Task_Id;
- Time : Duration;
- Mode : ST.Delay_Modes)
+ (Self_ID : Task_Id;
+ Time : Duration;
+ Mode : ST.Delay_Modes)
is
Orig : constant Duration := Monotonic_Clock;
Absolute : Duration;
Aborted : Boolean := False;
begin
- SSL.Abort_Defer.all;
-
if Mode = Relative then
Absolute := Orig + Time;
Ticks := To_Clock_Ticks (Time);
if Ticks > 0 and then Ticks < int'Last then
- -- The first tick will delay anytime between 0 and
- -- 1 / sysClkRateGet seconds, so we need to add one to
- -- be on the safe side.
+ -- First tick will delay anytime between 0 and 1 / sysClkRateGet
+ -- seconds, so we need to add one to be on the safe side.
Ticks := Ticks + 1;
end if;
end if;
if Ticks > 0 then
- -- Modifying State and Pending_Priority_Change, locking the TCB.
+
+ -- Modifying State and Pending_Priority_Change, locking the TCB
+
if Single_Lock then
Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER);
else
Result := semTake (Self_ID.Common.LL.CV, Ticks);
if Result /= 0 then
+
-- If Ticks = int'last, it was most probably truncated
-- so let's make another round after recomputing Ticks
-- from the the absolute time.
end if;
-- Take back the lock after having slept, to protect further
- -- access to Self_ID
+ -- access to Self_ID.
if Single_Lock then
Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER);
else
taskDelay (0);
end if;
-
- SSL.Abort_Undefer.all;
end Timed_Delay;
---------------------
(T.Common.LL.Thread, To_VxWorks_Priority (int (Prio)));
pragma Assert (Result = 0);
- if FIFO_Within_Priorities then
+ if Dispatching_Policy = 'F' then
-- Annex D requirement [RM D.2.2 par. 9]:
+
-- If the task drops its priority due to the loss of inherited
-- priority, it is added at the head of the ready queue for its
-- new active priority.
procedure Enter_Task (Self_ID : Task_Id) is
procedure Init_Float;
pragma Import (C, Init_Float, "__gnat_init_float");
- -- Properly initializes the FPU for PPC/MIPS systems.
+ -- Properly initializes the FPU for PPC/MIPS systems
begin
Self_ID.Common.LL.Thread := taskIdSelf;
Init_Float;
- -- Install the signal handlers.
+ -- Install the signal handlers
+
-- This is called for each task since there is no signal inheritance
-- between VxWorks tasks.
is
Adjusted_Stack_Size : size_t;
begin
- if Stack_Size = Unspecified_Size then
- Adjusted_Stack_Size := size_t (Default_Stack_Size);
+ -- Ask for four extra bytes of stack space so that the ATCB pointer can
+ -- be stored below the stack limit, plus extra space for the frame of
+ -- Task_Wrapper. This is so the user gets the amount of stack requested
+ -- exclusive of the needs.
- elsif Stack_Size < Minimum_Stack_Size then
- Adjusted_Stack_Size := size_t (Minimum_Stack_Size);
+ -- We also have to allocate n more bytes for the task name storage and
+ -- enough space for the Wind Task Control Block which is around 0x778
+ -- bytes. VxWorks also seems to carve out additional space, so use 2048
+ -- as a nice round number. We might want to increment to the nearest
+ -- page size in case we ever support VxVMI.
- else
- Adjusted_Stack_Size := size_t (Stack_Size);
- end if;
+ -- ??? - we should come back and visit this so we can set the task name
+ -- to something appropriate.
- -- Ask for 4 extra bytes of stack space so that the ATCB
- -- pointer can be stored below the stack limit, plus extra
- -- space for the frame of Task_Wrapper. This is so the user
- -- gets the amount of stack requested exclusive of the needs
- -- of the runtime.
- --
- -- We also have to allocate n more bytes for the task name
- -- storage and enough space for the Wind Task Control Block
- -- which is around 0x778 bytes. VxWorks also seems to carve out
- -- additional space, so use 2048 as a nice round number.
- -- We might want to increment to the nearest page size in
- -- case we ever support VxVMI.
- --
- -- XXX - we should come back and visit this so we can
- -- set the task name to something appropriate.
-
- Adjusted_Stack_Size := Adjusted_Stack_Size + 2048;
+ Adjusted_Stack_Size := size_t (Stack_Size) + 2048;
-- Since the initial signal mask of a thread is inherited from the
- -- creator, and the Environment task has all its signals masked, we
- -- do not need to manipulate caller's signal mask at this point.
- -- All tasks in RTS will have All_Tasks_Mask initially.
+ -- creator, and the Environment task has all its signals masked, we do
+ -- not need to manipulate caller's signal mask at this point. All tasks
+ -- in RTS will have All_Tasks_Mask initially.
if T.Common.Task_Image_Len = 0 then
T.Common.LL.Thread := taskSpawn
else
declare
Name : aliased String (1 .. T.Common.Task_Image_Len + 1);
+
begin
Name (1 .. Name'Last - 1) :=
T.Common.Task_Image (1 .. T.Common.Task_Image_Len);
Free (Tmp);
if Is_Self then
- Result := taskVarDelete (taskIdSelf, ATCB_Key'Access);
- pragma Assert (Result /= ERROR);
+ Specific.Delete;
end if;
end Finalize_TCB;
procedure Abort_Task (T : Task_Id) is
Result : int;
-
begin
Result := kill (T.Common.LL.Thread,
- Signal (Interrupt_Management.Abort_Task_Signal));
+ Signal (Interrupt_Management.Abort_Task_Signal));
pragma Assert (Result = 0);
end Abort_Task;
----------------
+ -- 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
+
+ -- Use simpler binary semaphore instead of VxWorks
+ -- mutual exclusion semaphore, because we don't need
+ -- the fancier semantics and their overhead.
+
+ S.L := semBCreate (SEM_Q_FIFO, SEM_FULL);
+
+ -- Initialize internal condition variable
+
+ S.CV := semBCreate (SEM_Q_FIFO, SEM_EMPTY);
+ end Initialize;
+
+ --------------
+ -- Finalize --
+ --------------
+
+ procedure Finalize (S : in out Suspension_Object) is
+ Result : STATUS;
+ begin
+ -- Destroy internal mutex
+
+ Result := semDelete (S.L);
+ pragma Assert (Result = OK);
+
+ -- Destroy internal condition variable
+
+ Result := semDelete (S.CV);
+ pragma Assert (Result = OK);
+ 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
+ Result : STATUS;
+ begin
+ SSL.Abort_Defer.all;
+
+ Result := semTake (S.L, WAIT_FOREVER);
+ pragma Assert (Result = OK);
+
+ S.State := False;
+
+ Result := semGive (S.L);
+ pragma Assert (Result = OK);
+
+ SSL.Abort_Undefer.all;
+ end Set_False;
+
+ --------------
+ -- Set_True --
+ --------------
+
+ procedure Set_True (S : in out Suspension_Object) is
+ Result : STATUS;
+ begin
+ SSL.Abort_Defer.all;
+
+ Result := semTake (S.L, WAIT_FOREVER);
+ pragma Assert (Result = OK);
+
+ -- 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 := semGive (S.CV);
+ pragma Assert (Result = OK);
+ else
+ S.State := True;
+ end if;
+
+ Result := semGive (S.L);
+ pragma Assert (Result = OK);
+
+ SSL.Abort_Undefer.all;
+ end Set_True;
+
+ ------------------------
+ -- Suspend_Until_True --
+ ------------------------
+
+ procedure Suspend_Until_True (S : in out Suspension_Object) is
+ Result : STATUS;
+ begin
+ SSL.Abort_Defer.all;
+
+ Result := semTake (S.L, WAIT_FOREVER);
+
+ 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).
+
+ Result := semGive (S.L);
+ pragma Assert (Result = OK);
+
+ 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;
+
+ Result := semGive (S.L);
+ pragma Assert (Result = 0);
+
+ SSL.Abort_Undefer.all;
+ else
+ S.Waiting := True;
+
+ -- Release the mutex before sleeping
+
+ Result := semGive (S.L);
+ pragma Assert (Result = OK);
+
+ SSL.Abort_Undefer.all;
+
+ Result := semTake (S.CV, WAIT_FOREVER);
+ pragma Assert (Result = 0);
+ end if;
+ end if;
+ end Suspend_Until_True;
+
+ ----------------
-- Check_Exit --
----------------
procedure Initialize (Environment_Task : Task_Id) is
Result : int;
-
begin
+ Environment_Task_Id := Environment_Task;
+
+ Interrupt_Management.Initialize;
+ Specific.Initialize;
+
if Locking_Policy = 'C' then
Mutex_Protocol := Prio_Protect;
elsif Locking_Policy = 'I' then
end if;
if Time_Slice_Val > 0 then
- Result := kernelTimeSlice
+ Result := Set_Time_Slice
(To_Clock_Ticks
(Duration (Time_Slice_Val) / Duration (1_000_000.0)));
end if;
end if;
end loop;
- Environment_Task_Id := Environment_Task;
-
- -- Initialize the lock used to synchronize chain of all ATCBs.
+ -- Initialize the lock used to synchronize chain of all ATCBs
Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
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