------------------------------------------------------------------------------
-- --
--- 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) 1992-2005, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2007, 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, --
with System.Interrupt_Management;
-- used for Keep_Unmasked
--- Abort_Task_Signal
+-- Abort_Task_Interrupt
-- Signal_ID
-- Initialize_Interrupts
+with Interfaces.C;
+
with System.Soft_Links;
--- used for Defer/Undefer_Abort
+-- used for Abort_Defer/Undefer
--- 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
+-- 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 System.OS_Interface;
--- used for various type, constant, and operations
-
-with System.Parameters;
--- used for Size_Type
-
-with System.Tasking;
--- used for Ada_Task_Control_Block
--- Task_Id
--- ATCB components and types
-
-with Interfaces.C;
-
-with Unchecked_Conversion;
-with Unchecked_Deallocation;
+with Ada.Unchecked_Conversion;
+with Ada.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;
-- 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
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
+ function Get_Policy (Prio : System.Any_Priority) return Character;
+ pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
+ -- Get priority specific dispatching policy
Mutex_Protocol : Priority_Type;
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?
pragma Inline (Set);
-- 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
procedure Install_Signal_Handlers;
-- Install the default signal handlers for the current task
- function To_Address is new Unchecked_Conversion (Task_Id, System.Address);
+ function To_Address is
+ new Ada.Unchecked_Conversion (Task_Id, System.Address);
-------------------
-- Abort_Handler --
-- Make sure signals used for RTS internal purpose are unmasked
- Result := pthread_sigmask (SIG_UNBLOCK,
- Unblocked_Signal_Mask'Unchecked_Access, Old_Set'Unchecked_Access);
+ Result :=
+ pthread_sigmask
+ (SIG_UNBLOCK,
+ Unblocked_Signal_Mask'Unchecked_Access,
+ Old_Set'Unchecked_Access);
pragma Assert (Result = 0);
raise Standard'Abort_Signal;
Result :=
sigaction
- (Signal (Interrupt_Management.Abort_Task_Signal),
+ (Signal (Interrupt_Management.Abort_Task_Interrupt),
act'Unchecked_Access,
old_act'Unchecked_Access);
pragma Assert (Result = 0);
-- Initialize_Lock --
---------------------
- procedure Initialize_Lock (Prio : System.Any_Priority; L : access Lock) is
+ procedure Initialize_Lock
+ (Prio : System.Any_Priority;
+ L : not null access Lock)
+ is
begin
L.Mutex := semMCreate (SEM_Q_PRIORITY + SEM_INVERSION_SAFE);
L.Prio_Ceiling := int (Prio);
pragma Assert (L.Mutex /= 0);
end Initialize_Lock;
- procedure Initialize_Lock (L : access RTS_Lock; Level : Lock_Level) is
+ procedure Initialize_Lock
+ (L : not null access RTS_Lock;
+ Level : Lock_Level)
+ is
pragma Unreferenced (Level);
-
begin
L.Mutex := semMCreate (SEM_Q_PRIORITY + SEM_INVERSION_SAFE);
L.Prio_Ceiling := int (System.Any_Priority'Last);
-- Finalize_Lock --
-------------------
- procedure Finalize_Lock (L : access Lock) is
+ procedure Finalize_Lock (L : not null access Lock) is
Result : int;
-
begin
Result := semDelete (L.Mutex);
pragma Assert (Result = 0);
end Finalize_Lock;
- procedure Finalize_Lock (L : access RTS_Lock) is
+ procedure Finalize_Lock (L : not null access RTS_Lock) is
Result : int;
-
begin
Result := semDelete (L.Mutex);
pragma Assert (Result = 0);
-- Write_Lock --
----------------
- procedure Write_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
+ procedure Write_Lock
+ (L : not null access Lock;
+ Ceiling_Violation : out Boolean)
+ is
Result : int;
begin
end Write_Lock;
procedure Write_Lock
- (L : access RTS_Lock;
+ (L : not null access RTS_Lock;
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);
-- Read_Lock --
---------------
- procedure Read_Lock (L : access Lock; Ceiling_Violation : out Boolean) is
+ 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 : access Lock) is
- Result : int;
-
+ procedure Unlock (L : not null access Lock) is
+ Result : int;
begin
Result := semGive (L.Mutex);
pragma Assert (Result = 0);
end Unlock;
- procedure Unlock (L : access RTS_Lock; Global_Lock : Boolean := False) is
+ procedure Unlock
+ (L : not null 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);
end if;
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 --
-----------
if Ticks /= int'Last then
Timedout := True;
+
else
Ticks := To_Clock_Ticks (Absolute - Monotonic_Clock);
-- 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;
Ticks : int;
Timedout : Boolean;
- Result : int;
Aborted : Boolean := False;
- begin
- SSL.Abort_Defer.all;
+ Result : int;
+ pragma Warnings (Off, Result);
+ begin
if Mode = Relative then
Absolute := Orig + Time;
Ticks := To_Clock_Ticks (Time);
if Ticks > 0 then
- -- Modifying State and Pending_Priority_Change, locking the TCB
+ -- Modifying State, locking the TCB
if Single_Lock then
Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER);
Timedout := False;
loop
- if Self_ID.Pending_Priority_Change then
- Self_ID.Pending_Priority_Change := False;
- Self_ID.Common.Base_Priority := Self_ID.New_Base_Priority;
- Set_Priority (Self_ID, Self_ID.Common.Base_Priority);
- end if;
-
Aborted := Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
-- Release the TCB before sleeping
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
-
- -- Annex D requirement [RM D.2.2 par. 9]:
+ if (Dispatching_Policy = 'F' or else Get_Policy (Prio) = 'F')
+ and then Loss_Of_Inheritance
+ and then Prio < T.Common.Current_Priority
+ then
+ -- Annex D requirement (RM D.2.2(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.
- if Loss_Of_Inheritance
- and then Prio < T.Common.Current_Priority
- then
- Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
- Prio_Array (T.Common.Base_Priority) := Array_Item;
+ Array_Item := Prio_Array (T.Common.Base_Priority) + 1;
+ Prio_Array (T.Common.Base_Priority) := Array_Item;
- loop
- -- Give some processes a chance to arrive
+ loop
+ -- Give some processes a chance to arrive
- taskDelay (0);
+ taskDelay (0);
- -- Then wait for our turn to proceed
+ -- Then wait for our turn to proceed
- exit when Array_Item = Prio_Array (T.Common.Base_Priority)
- or else Prio_Array (T.Common.Base_Priority) = 1;
- end loop;
+ exit when Array_Item = Prio_Array (T.Common.Base_Priority)
+ or else Prio_Array (T.Common.Base_Priority) = 1;
+ end loop;
- Prio_Array (T.Common.Base_Priority) :=
- Prio_Array (T.Common.Base_Priority) - 1;
- end if;
+ Prio_Array (T.Common.Base_Priority) :=
+ Prio_Array (T.Common.Base_Priority) - 1;
end if;
T.Common.Current_Priority := Prio;
-- Properly initializes the FPU for PPC/MIPS systems
begin
+ -- Store the user-level task id in the Thread field (to be used
+ -- internally by the run-time system) and the kernel-level task id in
+ -- the LWP field (to be used by the debugger).
+
Self_ID.Common.LL.Thread := taskIdSelf;
+ Self_ID.Common.LL.LWP := getpid;
+
Specific.Set (Self_ID);
Init_Float;
if Self_ID.Common.LL.CV = 0 then
Succeeded := False;
+
else
Succeeded := True;
is
Adjusted_Stack_Size : size_t;
begin
- if Stack_Size = Unspecified_Size then
- Adjusted_Stack_Size := size_t (Default_Stack_Size);
-
- elsif Stack_Size < Minimum_Stack_Size then
- Adjusted_Stack_Size := size_t (Minimum_Stack_Size);
-
- else
- Adjusted_Stack_Size := size_t (Stack_Size);
- end if;
-
-- 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
- --
+ -- exclusive of the needs.
+
-- 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
+
+ -- ??? - 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.
- if T.Common.Task_Image_Len = 0 then
- T.Common.LL.Thread := taskSpawn
- (System.Null_Address,
- To_VxWorks_Priority (int (Priority)),
- VX_FP_TASK,
- Adjusted_Stack_Size,
- Wrapper,
- To_Address (T));
- else
- declare
- Name : aliased String (1 .. T.Common.Task_Image_Len + 1);
+ -- We now compute the VxWorks task name and options, then spawn ...
- begin
+ declare
+ Name : aliased String (1 .. T.Common.Task_Image_Len + 1);
+ Name_Address : System.Address;
+ -- Task name we are going to hand down to VxWorks
+
+ function Get_Task_Options return int;
+ pragma Import (C, Get_Task_Options, "__gnat_get_task_options");
+ -- Function that returns the options to be set for the task that we
+ -- are creating. We fetch the options assigned to the current task,
+ -- so offering some user level control over the options for a task
+ -- hierarchy, and force VX_FP_TASK because it is almost always
+ -- required.
+
+ begin
+ -- If there is no Ada task name handy, let VxWorks choose one.
+ -- Otherwise, tell VxWorks what the Ada task name is.
+
+ if T.Common.Task_Image_Len = 0 then
+ Name_Address := System.Null_Address;
+ else
Name (1 .. Name'Last - 1) :=
T.Common.Task_Image (1 .. T.Common.Task_Image_Len);
Name (Name'Last) := ASCII.NUL;
+ Name_Address := Name'Address;
+ end if;
- T.Common.LL.Thread := taskSpawn
- (Name'Address,
- To_VxWorks_Priority (int (Priority)),
- VX_FP_TASK,
- Adjusted_Stack_Size,
- Wrapper,
- To_Address (T));
- end;
- end if;
+ -- Now spawn the VxWorks task for real
+
+ T.Common.LL.Thread :=
+ taskSpawn
+ (Name_Address,
+ To_VxWorks_Priority (int (Priority)),
+ Get_Task_Options,
+ Adjusted_Stack_Size,
+ Wrapper,
+ To_Address (T));
+ end;
if T.Common.LL.Thread = -1 then
Succeeded := False;
Is_Self : constant Boolean := (T = Self);
procedure Free is new
- Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
+ Ada.Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id);
begin
if not Single_Lock then
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));
+ Result :=
+ kill
+ (T.Common.LL.Thread,
+ Signal (Interrupt_Management.Abort_Task_Interrupt));
pragma Assert (Result = 0);
end Abort_Task;
----------------
+ -- Initialize --
+ ----------------
+
+ procedure Initialize (S : in out Suspension_Object) is
+ begin
+ -- Initialize internal state (always to False (RM D.10(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 --
----------------
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
- (To_Clock_Ticks
- (Duration (Time_Slice_Val) / Duration (1_000_000.0)));
+ Result :=
+ Set_Time_Slice
+ (To_Clock_Ticks
+ (Duration (Time_Slice_Val) / Duration (1_000_000.0)));
+
+ elsif Dispatching_Policy = 'R' then
+ Result := Set_Time_Slice (To_Clock_Ticks (0.01));
+
end if;
Result := sigemptyset (Unblocked_Signal_Mask'Access);
end if;
end loop;
- Environment_Task_Id := Environment_Task;
-
-- Initialize the lock used to synchronize chain of all ATCBs
Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
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