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------------------------------------------------------------------------------ -- -- -- GNU ADA 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) 1992-2011, 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 GNU/Linux (GNU/LinuxThreads) 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 Interfaces.C; with System.Task_Info; with System.Tasking.Debug; with System.Interrupt_Management; with System.OS_Primitives; with System.Stack_Checking.Operations; with System.Multiprocessors; 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; package SC renames System.Stack_Checking.Operations; use System.Tasking.Debug; use System.Tasking; use Interfaces.C; use System.OS_Interface; use System.Parameters; use System.OS_Primitives; use System.Task_Info; ---------------- -- 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 be unblocked in all tasks -- The followings are internal configuration constants needed Next_Serial_Number : Task_Serial_Number := 100; -- We start at 100 (reserve some special values for using in error checks) 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"); Locking_Policy : Character; pragma Import (C, Locking_Policy, "__gl_locking_policy"); Foreign_Task_Elaborated : aliased Boolean := True; -- Used to identified fake tasks (i.e., non-Ada Threads) Use_Alternate_Stack : constant Boolean := Alternate_Stack_Size /= 0; -- Whether to use an alternate signal stack for stack overflows Abort_Handler_Installed : Boolean := False; -- True if a handler for the abort signal is installed Null_Thread_Id : constant pthread_t := pthread_t'Last; -- Constant to indicate that the thread identifier has not yet been -- initialized. -------------------- -- Local Packages -- -------------------- package Specific is procedure Initialize (Environment_Task : Task_Id); pragma Inline (Initialize); -- Initialize various data needed by this package 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 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 ---------------------------------- -- 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) 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); ------------------- -- Abort_Handler -- ------------------- procedure Abort_Handler (signo : Signal) is pragma Unreferenced (signo); Self_Id : constant Task_Id := Self; Result : Interfaces.C.int; Old_Set : aliased sigset_t; begin -- It's not safe to raise an exception when using GCC ZCX mechanism. -- Note that we still need to install a signal handler, since in some -- cases (e.g. shutdown of the Server_Task in System.Interrupts) we -- need to send the Abort signal to a task. if ZCX_By_Default 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; -------------- -- 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; ----------------- -- Stack_Guard -- ----------------- -- The underlying thread system extends the memory (up to 2MB) when needed procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is pragma Unreferenced (T); pragma Unreferenced (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 renames Specific.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 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 pragma Unreferenced (Prio); begin if Locking_Policy = 'R' then declare RWlock_Attr : aliased pthread_rwlockattr_t; Result : Interfaces.C.int; begin -- Set the rwlock to prefer writer to avoid writers starvation Result := pthread_rwlockattr_init (RWlock_Attr'Access); pragma Assert (Result = 0); Result := pthread_rwlockattr_setkind_np (RWlock_Attr'Access, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP); pragma Assert (Result = 0); Result := pthread_rwlock_init (L.RW'Access, RWlock_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then raise Storage_Error with "Failed to allocate a lock"; end if; end; else declare Result : Interfaces.C.int; begin Result := pthread_mutex_init (L.WO'Access, null); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then raise Storage_Error with "Failed to allocate a lock"; end if; end; end if; end Initialize_Lock; procedure Initialize_Lock (L : not null access RTS_Lock; Level : Lock_Level) is pragma Unreferenced (Level); Result : Interfaces.C.int; begin Result := pthread_mutex_init (L, null); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then raise Storage_Error; end if; end Initialize_Lock; ------------------- -- Finalize_Lock -- ------------------- procedure Finalize_Lock (L : not null access Lock) is Result : Interfaces.C.int; begin if Locking_Policy = 'R' then Result := pthread_rwlock_destroy (L.RW'Access); else Result := pthread_mutex_destroy (L.WO'Access); end if; pragma Assert (Result = 0); end Finalize_Lock; procedure Finalize_Lock (L : not null access RTS_Lock) is Result : Interfaces.C.int; begin Result := pthread_mutex_destroy (L); pragma Assert (Result = 0); end Finalize_Lock; ---------------- -- Write_Lock -- ---------------- procedure Write_Lock (L : not null access Lock; Ceiling_Violation : out Boolean) is Result : Interfaces.C.int; begin if Locking_Policy = 'R' then Result := pthread_rwlock_wrlock (L.RW'Access); else Result := pthread_mutex_lock (L.WO'Access); end if; Ceiling_Violation := Result = EINVAL; -- Assume the cause of EINVAL is a priority ceiling violation pragma Assert (Result = 0 or else Result = EINVAL); end Write_Lock; procedure Write_Lock (L : not null access RTS_Lock; Global_Lock : Boolean := False) is Result : Interfaces.C.int; begin if not Single_Lock or else Global_Lock then Result := pthread_mutex_lock (L); pragma Assert (Result = 0); end if; end Write_Lock; procedure Write_Lock (T : Task_Id) is Result : Interfaces.C.int; begin if not Single_Lock then Result := pthread_mutex_lock (T.Common.LL.L'Access); pragma Assert (Result = 0); end if; end Write_Lock; --------------- -- Read_Lock -- --------------- procedure Read_Lock (L : not null access Lock; Ceiling_Violation : out Boolean) is Result : Interfaces.C.int; begin if Locking_Policy = 'R' then Result := pthread_rwlock_rdlock (L.RW'Access); else Result := pthread_mutex_lock (L.WO'Access); end if; Ceiling_Violation := Result = EINVAL; -- Assume the cause of EINVAL is a priority ceiling violation pragma Assert (Result = 0 or else Result = EINVAL); end Read_Lock; ------------ -- Unlock -- ------------ procedure Unlock (L : not null access Lock) is Result : Interfaces.C.int; begin if Locking_Policy = 'R' then Result := pthread_rwlock_unlock (L.RW'Access); else Result := pthread_mutex_unlock (L.WO'Access); end if; pragma Assert (Result = 0); end Unlock; procedure Unlock (L : not null access RTS_Lock; Global_Lock : Boolean := False) is Result : Interfaces.C.int; begin if not Single_Lock or else Global_Lock then Result := pthread_mutex_unlock (L); pragma Assert (Result = 0); end if; end Unlock; procedure Unlock (T : Task_Id) is Result : Interfaces.C.int; begin if not Single_Lock then Result := pthread_mutex_unlock (T.Common.LL.L'Access); 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 : Interfaces.C.int; begin pragma Assert (Self_ID = Self); Result := pthread_cond_wait (cond => Self_ID.Common.LL.CV'Access, mutex => (if Single_Lock then Single_RTS_Lock'Access else Self_ID.Common.LL.L'Access)); -- EINTR is not considered a failure pragma Assert (Result = 0 or else Result = EINTR); 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); Base_Time : constant Duration := Monotonic_Clock; Check_Time : Duration := Base_Time; Abs_Time : Duration; Request : aliased timespec; Result : Interfaces.C.int; begin Timedout := True; Yielded := False; Abs_Time := (if Mode = Relative then Duration'Min (Time, Max_Sensible_Delay) + Check_Time else Duration'Min (Check_Time + Max_Sensible_Delay, Time)); if Abs_Time > Check_Time then Request := To_Timespec (Abs_Time); loop exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level; Result := pthread_cond_timedwait (cond => Self_ID.Common.LL.CV'Access, mutex => (if Single_Lock then Single_RTS_Lock'Access else Self_ID.Common.LL.L'Access), abstime => Request'Access); Check_Time := Monotonic_Clock; exit when Abs_Time <= Check_Time or else Check_Time < Base_Time; if Result = 0 or else Result = EINTR then -- Somebody may have called Wakeup for us Timedout := False; exit; end if; pragma Assert (Result = ETIMEDOUT); end loop; end if; end Timed_Sleep; ----------------- -- Timed_Delay -- ----------------- -- This is for use in implementing delay statements, so we assume the -- caller is abort-deferred but is holding no locks. procedure Timed_Delay (Self_ID : Task_Id; Time : Duration; Mode : ST.Delay_Modes) is Base_Time : constant Duration := Monotonic_Clock; Check_Time : Duration := Base_Time; Abs_Time : Duration; Request : aliased timespec; Result : Interfaces.C.int; pragma Warnings (Off, Result); begin if Single_Lock then Lock_RTS; end if; Write_Lock (Self_ID); Abs_Time := (if Mode = Relative then Time + Check_Time else Duration'Min (Check_Time + Max_Sensible_Delay, Time)); if Abs_Time > Check_Time then Request := To_Timespec (Abs_Time); Self_ID.Common.State := Delay_Sleep; loop exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level; Result := pthread_cond_timedwait (cond => Self_ID.Common.LL.CV'Access, mutex => (if Single_Lock then Single_RTS_Lock'Access else Self_ID.Common.LL.L'Access), abstime => Request'Access); Check_Time := Monotonic_Clock; exit when Abs_Time <= Check_Time or else Check_Time < Base_Time; pragma Assert (Result = 0 or else Result = ETIMEDOUT or else Result = EINTR); end loop; Self_ID.Common.State := Runnable; end if; Unlock (Self_ID); if Single_Lock then Unlock_RTS; end if; Result := sched_yield; end Timed_Delay; --------------------- -- Monotonic_Clock -- --------------------- function Monotonic_Clock return Duration is use Interfaces; type timeval is array (1 .. 2) of C.long; procedure timeval_to_duration (T : not null access timeval; sec : not null access C.long; usec : not null access C.long); pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration"); Micro : constant := 10**6; sec : aliased C.long; usec : aliased C.long; TV : aliased timeval; Result : int; function gettimeofday (Tv : access timeval; Tz : System.Address := System.Null_Address) return int; pragma Import (C, gettimeofday, "gettimeofday"); begin Result := gettimeofday (TV'Access, System.Null_Address); pragma Assert (Result = 0); timeval_to_duration (TV'Access, sec'Access, usec'Access); return Duration (sec) + Duration (usec) / Micro; end Monotonic_Clock; ------------------- -- RT_Resolution -- ------------------- function RT_Resolution return Duration is begin return 10#1.0#E-6; end RT_Resolution; ------------ -- Wakeup -- ------------ procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is pragma Unreferenced (Reason); Result : Interfaces.C.int; begin Result := pthread_cond_signal (T.Common.LL.CV'Access); pragma Assert (Result = 0); end Wakeup; ----------- -- Yield -- ----------- procedure Yield (Do_Yield : Boolean := True) is Result : Interfaces.C.int; pragma Unreferenced (Result); begin if Do_Yield then Result := sched_yield; end if; end Yield; ------------------ -- Set_Priority -- ------------------ procedure Set_Priority (T : Task_Id; Prio : System.Any_Priority; Loss_Of_Inheritance : Boolean := False) is pragma Unreferenced (Loss_Of_Inheritance); Result : Interfaces.C.int; Param : aliased struct_sched_param; function Get_Policy (Prio : System.Any_Priority) return Character; pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching"); -- Get priority specific dispatching policy Priority_Specific_Policy : constant Character := Get_Policy (Prio); -- Upper case first character of the policy name corresponding to the -- task as set by a Priority_Specific_Dispatching pragma. begin T.Common.Current_Priority := Prio; -- Priorities are 1 .. 99 on GNU/Linux, so we map 0 .. 98 to 1 .. 99 Param.sched_priority := Interfaces.C.int (Prio) + 1; if Dispatching_Policy = 'R' or else Priority_Specific_Policy = 'R' or else Time_Slice_Val > 0 then Result := pthread_setschedparam (T.Common.LL.Thread, SCHED_RR, Param'Access); elsif Dispatching_Policy = 'F' or else Priority_Specific_Policy = 'F' or else Time_Slice_Val = 0 then Result := pthread_setschedparam (T.Common.LL.Thread, SCHED_FIFO, Param'Access); else Param.sched_priority := 0; Result := pthread_setschedparam (T.Common.LL.Thread, SCHED_OTHER, Param'Access); end if; pragma Assert (Result = 0 or else Result = EPERM); 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 begin if Self_ID.Common.Task_Info /= null and then Self_ID.Common.Task_Info.CPU_Affinity = No_CPU then raise Invalid_CPU_Number; end if; Self_ID.Common.LL.Thread := pthread_self; Self_ID.Common.LL.LWP := lwp_self; Specific.Set (Self_ID); if Use_Alternate_Stack and then Self_ID.Common.Task_Alternate_Stack /= Null_Address then declare Stack : aliased stack_t; Result : Interfaces.C.int; begin Stack.ss_sp := Self_ID.Common.Task_Alternate_Stack; Stack.ss_size := Alternate_Stack_Size; Stack.ss_flags := 0; Result := sigaltstack (Stack'Access, null); pragma Assert (Result = 0); end; end if; 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 (pthread_self); end if; end Register_Foreign_Thread; -------------------- -- Initialize_TCB -- -------------------- procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is Cond_Attr : aliased pthread_condattr_t; Result : Interfaces.C.int; begin -- Give the task a unique serial number Self_ID.Serial_Number := Next_Serial_Number; Next_Serial_Number := Next_Serial_Number + 1; pragma Assert (Next_Serial_Number /= 0); Self_ID.Common.LL.Thread := Null_Thread_Id; if not Single_Lock then Result := pthread_mutex_init (Self_ID.Common.LL.L'Access, null); pragma Assert (Result = 0 or else Result = ENOMEM); if Result /= 0 then Succeeded := False; return; end if; end if; Result := pthread_condattr_init (Cond_Attr'Access); pragma Assert (Result = 0); Result := pthread_cond_init (Self_ID.Common.LL.CV'Access, Cond_Attr'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = 0 then Succeeded := True; else if not Single_Lock then Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access); pragma Assert (Result = 0); end if; Succeeded := False; 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 Attributes : aliased pthread_attr_t; Adjusted_Stack_Size : Interfaces.C.size_t; Result : Interfaces.C.int; 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; Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size + Alternate_Stack_Size); Result := pthread_attr_init (Attributes'Access); pragma Assert (Result = 0 or else Result = ENOMEM); if Result /= 0 then Succeeded := False; return; end if; Result := pthread_attr_setstacksize (Attributes'Access, Adjusted_Stack_Size); pragma Assert (Result = 0); Result := pthread_attr_setdetachstate (Attributes'Access, PTHREAD_CREATE_DETACHED); pragma Assert (Result = 0); -- Set the required attributes for the creation of the thread -- Note: Previously, we called pthread_setaffinity_np (after thread -- creation but before thread activation) to set the affinity but it was -- not behaving as expected. Setting the required attributes for the -- creation of the thread works correctly and it is more appropriate. -- Do nothing if required support not provided by the operating system if pthread_attr_setaffinity_np'Address = System.Null_Address then null; -- Support is available elsif T.Common.Base_CPU /= System.Multiprocessors.Not_A_Specific_CPU then declare CPUs : constant size_t := Interfaces.C.size_t (System.Multiprocessors.Number_Of_CPUs); CPU_Set : constant cpu_set_t_ptr := CPU_ALLOC (CPUs); Size : constant size_t := CPU_ALLOC_SIZE (CPUs); begin CPU_ZERO (Size, CPU_Set); System.OS_Interface.CPU_SET (int (T.Common.Base_CPU), Size, CPU_Set); Result := pthread_attr_setaffinity_np (Attributes'Access, Size, CPU_Set); pragma Assert (Result = 0); CPU_FREE (CPU_Set); end; -- Handle Task_Info elsif T.Common.Task_Info /= null then Result := pthread_attr_setaffinity_np (Attributes'Access, CPU_SETSIZE / 8, T.Common.Task_Info.CPU_Affinity'Access); pragma Assert (Result = 0); -- Handle dispatching domains -- To avoid changing CPU affinities when not needed, we set the -- affinity only when assigning to a domain other than the default -- one, or when the default one has been modified. 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 CPUs : constant size_t := Interfaces.C.size_t (System.Multiprocessors.Number_Of_CPUs); CPU_Set : constant cpu_set_t_ptr := CPU_ALLOC (CPUs); Size : constant size_t := CPU_ALLOC_SIZE (CPUs); begin CPU_ZERO (Size, CPU_Set); -- Set the affinity to all the processors belonging to the -- dispatching domain. for Proc in T.Common.Domain'Range loop if T.Common.Domain (Proc) then System.OS_Interface.CPU_SET (int (Proc), Size, CPU_Set); end if; end loop; Result := pthread_attr_setaffinity_np (Attributes'Access, Size, CPU_Set); pragma Assert (Result = 0); CPU_FREE (CPU_Set); end; end if; -- 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. -- Note: the use of Unrestricted_Access in the following call is needed -- because otherwise we have an error of getting a access-to-volatile -- value which points to a non-volatile object. But in this case it is -- safe to do this, since we know we have no problems with aliasing and -- Unrestricted_Access bypasses this check. Result := pthread_create (T.Common.LL.Thread'Unrestricted_Access, Attributes'Access, Thread_Body_Access (Wrapper), To_Address (T)); pragma Assert (Result = 0 or else Result = EAGAIN or else Result = ENOMEM); if Result /= 0 then Succeeded := False; Result := pthread_attr_destroy (Attributes'Access); pragma Assert (Result = 0); return; end if; Succeeded := True; Result := pthread_attr_destroy (Attributes'Access); pragma Assert (Result = 0); Set_Priority (T, Priority); end Create_Task; ------------------ -- Finalize_TCB -- ------------------ procedure Finalize_TCB (T : Task_Id) is Result : Interfaces.C.int; begin if not Single_Lock then Result := pthread_mutex_destroy (T.Common.LL.L'Access); pragma Assert (Result = 0); end if; Result := pthread_cond_destroy (T.Common.LL.CV'Access); pragma Assert (Result = 0); if T.Known_Tasks_Index /= -1 then Known_Tasks (T.Known_Tasks_Index) := null; end if; SC.Invalidate_Stack_Cache (T.Common.Compiler_Data.Pri_Stack_Info'Access); 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 Result : Interfaces.C.int; begin if Abort_Handler_Installed then Result := pthread_kill (T.Common.LL.Thread, Signal (System.Interrupt_Management.Abort_Task_Interrupt)); pragma Assert (Result = 0); end if; end Abort_Task; ---------------- -- Initialize -- ---------------- procedure Initialize (S : in out Suspension_Object) is Result : Interfaces.C.int; begin -- Initialize internal state (always to False (RM D.10(6))) S.State := False; S.Waiting := False; -- Initialize internal mutex Result := pthread_mutex_init (S.L'Access, null); pragma Assert (Result = 0 or else Result = ENOMEM); if Result = ENOMEM then raise Storage_Error; end if; -- Initialize internal condition variable Result := pthread_cond_init (S.CV'Access, null); pragma Assert (Result = 0 or else Result = ENOMEM); if Result /= 0 then Result := pthread_mutex_destroy (S.L'Access); pragma Assert (Result = 0); if Result = ENOMEM then raise Storage_Error; end if; end if; end Initialize; -------------- -- Finalize -- -------------- procedure Finalize (S : in out Suspension_Object) is Result : Interfaces.C.int; begin -- Destroy internal mutex Result := pthread_mutex_destroy (S.L'Access); pragma Assert (Result = 0); -- Destroy internal condition variable Result := pthread_cond_destroy (S.CV'Access); pragma Assert (Result = 0); 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 : Interfaces.C.int; begin SSL.Abort_Defer.all; Result := pthread_mutex_lock (S.L'Access); pragma Assert (Result = 0); S.State := False; Result := pthread_mutex_unlock (S.L'Access); pragma Assert (Result = 0); SSL.Abort_Undefer.all; end Set_False; -------------- -- Set_True -- -------------- procedure Set_True (S : in out Suspension_Object) is Result : Interfaces.C.int; begin SSL.Abort_Defer.all; Result := pthread_mutex_lock (S.L'Access); pragma Assert (Result = 0); -- 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 := pthread_cond_signal (S.CV'Access); pragma Assert (Result = 0); else S.State := True; end if; Result := pthread_mutex_unlock (S.L'Access); pragma Assert (Result = 0); SSL.Abort_Undefer.all; end Set_True; ------------------------ -- Suspend_Until_True -- ------------------------ procedure Suspend_Until_True (S : in out Suspension_Object) is Result : Interfaces.C.int; begin SSL.Abort_Defer.all; Result := pthread_mutex_lock (S.L'Access); pragma Assert (Result = 0); if S.Waiting then -- Program_Error must be raised upon calling Suspend_Until_True -- if another task is already waiting on that suspension object -- (RM D.10(10)). Result := pthread_mutex_unlock (S.L'Access); pragma Assert (Result = 0); 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; else S.Waiting := True; loop -- Loop in case pthread_cond_wait returns earlier than expected -- (e.g. in case of EINTR caused by a signal). This should not -- happen with the current Linux implementation of pthread, but -- POSIX does not guarantee it so this may change in future. Result := pthread_cond_wait (S.CV'Access, S.L'Access); pragma Assert (Result = 0 or else Result = EINTR); exit when not S.Waiting; end loop; end if; Result := pthread_mutex_unlock (S.L'Access); pragma Assert (Result = 0); SSL.Abort_Undefer.all; 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; ------------------ -- 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 pthread_kill (T.Common.LL.Thread, SIGSTOP) = 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 /= Thread_Self then return pthread_kill (T.Common.LL.Thread, SIGCONT) = 0; 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; ---------------- -- Initialize -- ---------------- procedure Initialize (Environment_Task : Task_Id) is act : aliased struct_sigaction; old_act : aliased struct_sigaction; Tmp_Set : aliased sigset_t; Result : Interfaces.C.int; -- Whether to use an alternate signal stack for stack overflows function State (Int : System.Interrupt_Management.Interrupt_ID) return Character; pragma Import (C, State, "__gnat_get_interrupt_state"); -- Get interrupt state. Defined in a-init.c -- The input argument is the interrupt number, -- and the result is one of the following: Default : constant Character := 's'; -- 'n' this interrupt not set by any Interrupt_State pragma -- 'u' Interrupt_State pragma set state to User -- 'r' Interrupt_State pragma set state to Runtime -- 's' Interrupt_State pragma set state to System (use "default" -- system handler) use type System.Multiprocessors.CPU_Range; begin Environment_Task_Id := Environment_Task; Interrupt_Management.Initialize; -- Prepare the set of signals that should be unblocked in all tasks Result := sigemptyset (Unblocked_Signal_Mask'Access); pragma Assert (Result = 0); for J in Interrupt_Management.Interrupt_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_Lock (Single_RTS_Lock'Access, RTS_Lock_Level); -- Initialize the global RTS lock Specific.Initialize (Environment_Task); if Use_Alternate_Stack then Environment_Task.Common.Task_Alternate_Stack := Alternate_Stack'Address; end if; -- 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); if State (System.Interrupt_Management.Abort_Task_Interrupt) /= Default then 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); Abort_Handler_Installed := True; end if; -- pragma CPU and dispatching domains for the environment task Set_Task_Affinity (Environment_Task); end Initialize; ----------------------- -- Set_Task_Affinity -- ----------------------- procedure Set_Task_Affinity (T : ST.Task_Id) is use type System.Multiprocessors.CPU_Range; begin -- Do nothing if there is no support for setting affinities or 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 pthread_setaffinity_np'Address /= System.Null_Address and then T.Common.LL.Thread /= Null_Thread_Id then declare CPUs : constant size_t := Interfaces.C.size_t (System.Multiprocessors.Number_Of_CPUs); CPU_Set : cpu_set_t_ptr := null; Size : constant size_t := CPU_ALLOC_SIZE (CPUs); Result : Interfaces.C.int; begin -- We look at the specific CPU (Base_CPU) first, then at the -- Task_Info field, and finally at the assigned dispatching -- domain, if any. if T.Common.Base_CPU /= Multiprocessors.Not_A_Specific_CPU then -- Set the affinity to an unique CPU CPU_Set := CPU_ALLOC (CPUs); System.OS_Interface.CPU_ZERO (Size, CPU_Set); System.OS_Interface.CPU_SET (int (T.Common.Base_CPU), Size, CPU_Set); -- Handle Task_Info elsif T.Common.Task_Info /= null then CPU_Set := T.Common.Task_Info.CPU_Affinity'Access; -- Handle 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 -- Set the affinity to all the processors belonging to the -- dispatching domain. To avoid changing CPU affinities when -- not needed, we set the affinity only when assigning to a -- domain other than the default one, or when the default one -- has been modified. CPU_Set := CPU_ALLOC (CPUs); System.OS_Interface.CPU_ZERO (Size, CPU_Set); for Proc in T.Common.Domain'Range loop System.OS_Interface.CPU_SET (int (Proc), Size, CPU_Set); end loop; end if; -- We set the new affinity if needed. Otherwise, the new task -- will inherit its creator's CPU affinity mask (according to -- the documentation of pthread_setaffinity_np), which is -- consistent with Ada's required semantics. if CPU_Set /= null then Result := pthread_setaffinity_np (T.Common.LL.Thread, Size, CPU_Set); pragma Assert (Result = 0); CPU_FREE (CPU_Set); end if; end; end if; end Set_Task_Affinity; end System.Task_Primitives.Operations;
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