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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) 1992-2009, 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. -- -- -- ------------------------------------------------------------------------------ -- This is the VxWorks version of this package -- This package contains all the GNULL primitives that interface directly with -- the underlying OS. pragma Polling (Off); -- Turn off polling, we do not want ATC polling to take place during tasking -- operations. It causes infinite loops and other problems. with Ada.Unchecked_Conversion; with Ada.Unchecked_Deallocation; with Interfaces.C; with System.Tasking.Debug; with System.Interrupt_Management; 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. with System.Task_Info; with System.VxWorks.Ext; 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 System.VxWorks.Ext.t_id; use type Interfaces.C.int; 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. 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 mainly in Single_Lock mode, but also to protect All_Tasks_List Environment_Task_Id : Task_Id; -- 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 Time_Slice_Val : Integer; pragma Import (C, Time_Slice_Val, "__gl_time_slice_val"); Locking_Policy : Character; pragma Import (C, Locking_Policy, "__gl_locking_policy"); 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 Mutex_Protocol : Priority_Type; Foreign_Task_Elaborated : aliased Boolean := True; -- Used to identified fake tasks (i.e., non-Ada Threads) type Set_Stack_Limit_Proc_Acc is access procedure; pragma Convention (C, Set_Stack_Limit_Proc_Acc); Set_Stack_Limit_Hook : Set_Stack_Limit_Proc_Acc; pragma Import (C, Set_Stack_Limit_Hook, "__gnat_set_stack_limit_hook"); -- Procedure to be called when a task is created to set stack -- limit. -------------------- -- 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 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 end Specific; package body Specific is separate; -- 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 function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id is separate; ----------------------- -- Local Subprograms -- ----------------------- procedure Abort_Handler (signo : Signal); -- Handler for the abort (SIGABRT) signal to handle asynchronous abort procedure Install_Signal_Handlers; -- Install the default signal handlers for the current task function To_Address is new Ada.Unchecked_Conversion (Task_Id, System.Address); ------------------- -- Abort_Handler -- ------------------- procedure Abort_Handler (signo : Signal) is pragma Unreferenced (signo); Self_ID : constant Task_Id := Self; Old_Set : aliased sigset_t; Result : int; pragma Warnings (Off, Result); begin -- It is not safe to raise an exception when using ZCX and the GCC -- exception handling mechanism. if ZCX_By_Default and then GCC_ZCX_Support then return; end if; if Self_ID.Deferral_Level = 0 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level and then not Self_ID.Aborting then Self_ID.Aborting := True; -- Make sure signals used for RTS internal purpose are unmasked Result := pthread_sigmask (SIG_UNBLOCK, Unblocked_Signal_Mask'Access, Old_Set'Access); pragma Assert (Result = 0); raise Standard'Abort_Signal; end if; end Abort_Handler; ----------------- -- Stack_Guard -- ----------------- procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is pragma Unreferenced (T); pragma Unreferenced (On); begin -- Nothing needed (why not???) 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 renames Specific.Self; ----------------------------- -- Install_Signal_Handlers -- ----------------------------- procedure Install_Signal_Handlers is act : aliased struct_sigaction; old_act : aliased struct_sigaction; Tmp_Set : aliased sigset_t; Result : int; begin act.sa_flags := 0; act.sa_handler := Abort_Handler'Address; Result := sigemptyset (Tmp_Set'Access); pragma Assert (Result = 0); act.sa_mask := Tmp_Set; Result := sigaction (Signal (Interrupt_Management.Abort_Task_Interrupt), act'Unchecked_Access, old_act'Unchecked_Access); pragma Assert (Result = 0); Interrupt_Management.Initialize_Interrupts; end Install_Signal_Handlers; --------------------- -- Initialize_Lock -- --------------------- 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); L.Protocol := Mutex_Protocol; pragma Assert (L.Mutex /= 0); end Initialize_Lock; 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); L.Protocol := Mutex_Protocol; pragma Assert (L.Mutex /= 0); end Initialize_Lock; ------------------- -- Finalize_Lock -- ------------------- 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 : not null access RTS_Lock) is Result : int; begin Result := semDelete (L.Mutex); pragma Assert (Result = 0); end Finalize_Lock; ---------------- -- Write_Lock -- ---------------- procedure Write_Lock (L : not null 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 then Ceiling_Violation := True; return; else Ceiling_Violation := False; end if; Result := semTake (L.Mutex, WAIT_FOREVER); pragma Assert (Result = 0); end Write_Lock; procedure Write_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); pragma Assert (Result = 0); end if; end Write_Lock; procedure Write_Lock (T : Task_Id) is Result : int; begin if not Single_Lock then Result := semTake (T.Common.LL.L.Mutex, WAIT_FOREVER); pragma Assert (Result = 0); end if; 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 Result : int; begin Result := semGive (L.Mutex); pragma Assert (Result = 0); end Unlock; 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); pragma Assert (Result = 0); end if; end Unlock; procedure Unlock (T : Task_Id) is Result : int; begin if not Single_Lock then Result := semGive (T.Common.LL.L.Mutex); pragma Assert (Result = 0); 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 -- ----------- procedure Sleep (Self_ID : Task_Id; Reason : System.Tasking.Task_States) is pragma Unreferenced (Reason); Result : int; begin pragma Assert (Self_ID = Self); -- Release the mutex before sleeping Result := semGive (if Single_Lock then Single_RTS_Lock.Mutex else Self_ID.Common.LL.L.Mutex); 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. Result := semTake (Self_ID.Common.LL.CV, WAIT_FOREVER); pragma Assert (Result = 0); -- Take the mutex back Result := semTake ((if Single_Lock then Single_RTS_Lock.Mutex else Self_ID.Common.LL.L.Mutex), WAIT_FOREVER); pragma Assert (Result = 0); 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); Orig : constant Duration := Monotonic_Clock; Absolute : Duration; Ticks : int; Result : int; Wakeup : Boolean := False; begin Timedout := False; Yielded := True; 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. Ticks := To_Clock_Ticks (Time); if Ticks > 0 and then Ticks < int'Last then Ticks := Ticks + 1; end if; else Absolute := Time; Ticks := To_Clock_Ticks (Time - Monotonic_Clock); end if; if Ticks > 0 then loop -- Release the mutex before sleeping Result := semGive (if Single_Lock then Single_RTS_Lock.Mutex else Self_ID.Common.LL.L.Mutex); 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. 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 absolute time. if Ticks /= int'Last then Timedout := True; else Ticks := To_Clock_Ticks (Absolute - Monotonic_Clock); if Ticks < 0 then Timedout := True; end if; end if; end if; end if; -- Take the mutex back Result := semTake ((if Single_Lock then Single_RTS_Lock.Mutex else Self_ID.Common.LL.L.Mutex), WAIT_FOREVER); pragma Assert (Result = 0); exit when Timedout or Wakeup; end loop; else Timedout := True; -- Should never hold a lock while yielding if Single_Lock then Result := semGive (Single_RTS_Lock.Mutex); taskDelay (0); Result := semTake (Single_RTS_Lock.Mutex, WAIT_FOREVER); else Result := semGive (Self_ID.Common.LL.L.Mutex); taskDelay (0); Result := semTake (Self_ID.Common.LL.L.Mutex, WAIT_FOREVER); end if; end if; end Timed_Sleep; ----------------- -- Timed_Delay -- ----------------- -- 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) is Orig : constant Duration := Monotonic_Clock; Absolute : Duration; Ticks : int; Timedout : Boolean; Aborted : Boolean := False; Result : int; pragma Warnings (Off, Result); begin if Mode = Relative then Absolute := Orig + Time; Ticks := To_Clock_Ticks (Time); if Ticks > 0 and then Ticks < int'Last then -- 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; else Absolute := Time; Ticks := To_Clock_Ticks (Time - Orig); end if; if Ticks > 0 then -- Modifying State, locking the TCB Result := semTake ((if Single_Lock then Single_RTS_Lock.Mutex else Self_ID.Common.LL.L.Mutex), WAIT_FOREVER); pragma Assert (Result = 0); Self_ID.Common.State := Delay_Sleep; Timedout := False; loop Aborted := Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level; -- Release the TCB before sleeping Result := semGive (if Single_Lock then Single_RTS_Lock.Mutex else Self_ID.Common.LL.L.Mutex); pragma Assert (Result = 0); exit when Aborted; 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 absolute time. if errno = S_objLib_OBJ_TIMEOUT and then Ticks /= int'Last then Timedout := True; else Ticks := To_Clock_Ticks (Absolute - Monotonic_Clock); if Ticks < 0 then Timedout := True; end if; end if; end if; -- Take back the lock after having slept, to protect further -- access to Self_ID. Result := semTake ((if Single_Lock then Single_RTS_Lock.Mutex else Self_ID.Common.LL.L.Mutex), WAIT_FOREVER); pragma Assert (Result = 0); exit when Timedout; end loop; Self_ID.Common.State := Runnable; Result := semGive (if Single_Lock then Single_RTS_Lock.Mutex else Self_ID.Common.LL.L.Mutex); else taskDelay (0); end if; end Timed_Delay; --------------------- -- Monotonic_Clock -- --------------------- function Monotonic_Clock return Duration is TS : aliased timespec; Result : int; begin Result := clock_gettime (CLOCK_REALTIME, TS'Unchecked_Access); pragma Assert (Result = 0); return To_Duration (TS); end Monotonic_Clock; ------------------- -- RT_Resolution -- ------------------- function RT_Resolution return Duration is begin return 1.0 / Duration (sysClkRateGet); end RT_Resolution; ------------ -- Wakeup -- ------------ procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is pragma Unreferenced (Reason); Result : int; begin Result := semGive (T.Common.LL.CV); pragma Assert (Result = 0); end Wakeup; ----------- -- Yield -- ----------- procedure Yield (Do_Yield : Boolean := True) is pragma Unreferenced (Do_Yield); Result : int; pragma Unreferenced (Result); begin Result := taskDelay (0); end Yield; ------------------ -- Set_Priority -- ------------------ type Prio_Array_Type is array (System.Any_Priority) of Integer; pragma Atomic_Components (Prio_Array_Type); Prio_Array : Prio_Array_Type; -- Global array containing the id of the currently running task for each -- priority. Note that we assume that we are on a single processor with -- run-till-blocked scheduling. procedure Set_Priority (T : Task_Id; Prio : System.Any_Priority; Loss_Of_Inheritance : Boolean := False) is Array_Item : Integer; Result : int; begin Result := taskPrioritySet (T.Common.LL.Thread, To_VxWorks_Priority (int (Prio))); pragma Assert (Result = 0); 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. 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 taskDelay (0); -- 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; Prio_Array (T.Common.Base_Priority) := Prio_Array (T.Common.Base_Priority) - 1; end if; 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 -- ---------------- 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 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; -- Install the signal handlers -- This is called for each task since there is no signal inheritance -- between VxWorks tasks. Install_Signal_Handlers; -- If stack checking is enabled, set the stack limit for this task if Set_Stack_Limit_Hook /= null then Set_Stack_Limit_Hook.all; end if; end Enter_Task; -------------- -- New_ATCB -- -------------- function New_ATCB (Entry_Num : Task_Entry_Index) return Task_Id is begin return new Ada_Task_Control_Block (Entry_Num); end New_ATCB; ------------------- -- 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 (taskIdSelf); end if; end Register_Foreign_Thread; -------------------- -- Initialize_TCB -- -------------------- procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is begin Self_ID.Common.LL.CV := semBCreate (SEM_Q_PRIORITY, SEM_EMPTY); Self_ID.Common.LL.Thread := 0; if Self_ID.Common.LL.CV = 0 then Succeeded := False; else Succeeded := True; if not Single_Lock then Initialize_Lock (Self_ID.Common.LL.L'Access, ATCB_Level); end if; end if; 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 Adjusted_Stack_Size : size_t; Result : int; use System.Task_Info; begin -- 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. -- 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. -- ??? - we should come back and visit this so we can set the task name -- to something appropriate. 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. -- We now compute the VxWorks task name and options, then spawn ... 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; -- 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; -- Set processor affinity if T.Common.Task_Info /= Unspecified_Task_Info then Result := taskCpuAffinitySet (T.Common.LL.Thread, T.Common.Task_Info); if Result = -1 then taskDelete (T.Common.LL.Thread); T.Common.LL.Thread := -1; end if; end if; if T.Common.LL.Thread = -1 then Succeeded := False; else Succeeded := True; Task_Creation_Hook (T.Common.LL.Thread); Set_Priority (T, Priority); end if; end Create_Task; ------------------ -- Finalize_TCB -- ------------------ procedure Finalize_TCB (T : Task_Id) is Result : int; Tmp : Task_Id := T; Is_Self : constant Boolean := (T = Self); procedure Free is new Ada.Unchecked_Deallocation (Ada_Task_Control_Block, Task_Id); begin if not Single_Lock then Result := semDelete (T.Common.LL.L.Mutex); pragma Assert (Result = 0); end if; T.Common.LL.Thread := 0; Result := semDelete (T.Common.LL.CV); pragma Assert (Result = 0); if T.Known_Tasks_Index /= -1 then Known_Tasks (T.Known_Tasks_Index) := null; end if; Free (Tmp); if Is_Self then Specific.Delete; end if; 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 Result : int; begin 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 pragma Unmodified (S); -- S may be modified on other targets, but not on VxWorks 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 -- ---------------- -- Dummy version 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; ---------------------- -- 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, Global_Lock => True); end Lock_RTS; ---------------- -- Unlock_RTS -- ---------------- procedure Unlock_RTS is begin Unlock (Single_RTS_Lock'Access, Global_Lock => True); end Unlock_RTS; ------------------ -- Suspend_Task -- ------------------ function Suspend_Task (T : ST.Task_Id; Thread_Self : Thread_Id) return Boolean is begin if T.Common.LL.Thread /= 0 and then T.Common.LL.Thread /= Thread_Self then return taskSuspend (T.Common.LL.Thread) = 0; 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 /= 0 and then T.Common.LL.Thread /= Thread_Self then return taskResume (T.Common.LL.Thread) = 0; else return True; end if; end Resume_Task; -------------------- -- Stop_All_Tasks -- -------------------- procedure Stop_All_Tasks is Thread_Self : constant Thread_Id := taskIdSelf; C : Task_Id; Dummy : int; pragma Unreferenced (Dummy); begin Dummy := Int_Lock; C := All_Tasks_List; while C /= null loop if C.Common.LL.Thread /= 0 and then C.Common.LL.Thread /= Thread_Self then Dummy := Task_Stop (C.Common.LL.Thread); end if; C := C.Common.All_Tasks_Link; end loop; Dummy := Int_Unlock; end Stop_All_Tasks; --------------- -- Stop_Task -- --------------- function Stop_Task (T : ST.Task_Id) return Boolean is begin if T.Common.LL.Thread /= 0 then return Task_Stop (T.Common.LL.Thread) = 0; else return True; end if; end Stop_Task; ------------------- -- Continue_Task -- ------------------- function Continue_Task (T : ST.Task_Id) return Boolean is begin if T.Common.LL.Thread /= 0 then return Task_Cont (T.Common.LL.Thread) = 0; else return True; end if; end Continue_Task; ---------------- -- Initialize -- ---------------- 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 Mutex_Protocol := Prio_Inherit; else Mutex_Protocol := Prio_None; end if; if Time_Slice_Val > 0 then 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); pragma Assert (Result = 0); for J in Interrupt_Management.Signal_ID loop if System.Interrupt_Management.Keep_Unmasked (J) then Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J)); pragma Assert (Result = 0); end if; end loop; -- Initialize the lock used to synchronize chain of all ATCBs Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level); -- 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); end Initialize; end System.Task_Primitives.Operations;
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