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ubuntu-buildroot/output/build/host-gcc-initial-11.4.0/gcc/ada/libgnarl/s-taprop__linux.adb

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2024-04-01 15:19:46 +00:00
------------------------------------------------------------------------------
-- --
-- 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) 1992-2020, 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.
with Interfaces.C; use Interfaces; use type Interfaces.C.int;
with System.Task_Info;
with System.Tasking.Debug;
with System.Interrupt_Management;
with System.OS_Constants;
with System.OS_Primitives;
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 OSC renames System.OS_Constants;
package SSL renames System.Soft_Links;
use System.Tasking.Debug;
use System.Tasking;
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 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
package Monotonic is
function Monotonic_Clock return Duration;
pragma Inline (Monotonic_Clock);
-- Returns an absolute time, represented as an offset relative to some
-- unspecified starting point, typically system boot time. This clock is
-- not affected by discontinuous jumps in the system time.
function RT_Resolution return Duration;
pragma Inline (RT_Resolution);
-- Returns resolution of the underlying clock used to implement RT_Clock
procedure Timed_Sleep
(Self_ID : ST.Task_Id;
Time : Duration;
Mode : ST.Delay_Modes;
Reason : System.Tasking.Task_States;
Timedout : out Boolean;
Yielded : out Boolean);
-- Combination of Sleep (above) and Timed_Delay
procedure Timed_Delay
(Self_ID : ST.Task_Id;
Time : Duration;
Mode : ST.Delay_Modes);
-- Implement the semantics of the delay statement.
-- The caller should be abort-deferred and should not hold any locks.
end Monotonic;
package body Monotonic is separate;
----------------------------------
-- ATCB allocation/deallocation --
----------------------------------
package body ATCB_Allocation is separate;
-- The body of this package is shared across several targets
---------------------------------
-- Support for foreign threads --
---------------------------------
function Register_Foreign_Thread
(Thread : Thread_Id;
Sec_Stack_Size : Size_Type := Unspecified_Size) return Task_Id;
-- Allocate and initialize a new ATCB for the current Thread. The size of
-- the secondary stack can be optionally specified.
function Register_Foreign_Thread
(Thread : Thread_Id;
Sec_Stack_Size : Size_Type := Unspecified_Size)
return Task_Id is separate;
-----------------------
-- Local Subprograms --
-----------------------
procedure Abort_Handler (signo : Signal);
function GNAT_pthread_condattr_setup
(attr : access pthread_condattr_t) return C.int;
pragma Import
(C, GNAT_pthread_condattr_setup, "__gnat_pthread_condattr_setup");
function GNAT_has_cap_sys_nice return C.int;
pragma Import
(C, GNAT_has_cap_sys_nice, "__gnat_has_cap_sys_nice");
-- We do not have pragma Linker_Options ("-lcap"); here, because this
-- library is not present on many Linux systems. 'libcap' is the Linux
-- "capabilities" library, called by __gnat_has_cap_sys_nice.
function Prio_To_Linux_Prio (Prio : Any_Priority) return C.int is
(C.int (Prio) + 1);
-- Convert Ada priority to Linux priority. Priorities are 1 .. 99 on
-- GNU/Linux, so we map 0 .. 98 to 1 .. 99.
function Get_Ceiling_Support return Boolean;
-- Get the value of the Ceiling_Support constant (see below).
-- Note well: If this function or related code is modified, it should be
-- tested by hand, because automated testing doesn't exercise it.
-------------------------
-- Get_Ceiling_Support --
-------------------------
function Get_Ceiling_Support return Boolean is
Ceiling_Support : Boolean := False;
begin
if Locking_Policy /= 'C' then
return False;
end if;
declare
function geteuid return Integer;
pragma Import (C, geteuid, "geteuid");
Superuser : constant Boolean := geteuid = 0;
Has_Cap : constant C.int := GNAT_has_cap_sys_nice;
pragma Assert (Has_Cap in 0 | 1);
begin
Ceiling_Support := Superuser or else Has_Cap = 1;
end;
return Ceiling_Support;
end Get_Ceiling_Support;
pragma Warnings (Off, "non-preelaborable call not allowed*");
Ceiling_Support : constant Boolean := Get_Ceiling_Support;
pragma Warnings (On, "non-preelaborable call not allowed*");
-- True if the locking policy is Ceiling_Locking, and the current process
-- has permission to use this policy. The process has permission if it is
-- running as 'root', or if the capability was set by the setcap command,
-- as in "sudo /sbin/setcap cap_sys_nice=ep exe_file". If it doesn't have
-- permission, then a request for Ceiling_Locking is ignored.
type RTS_Lock_Ptr is not null access all RTS_Lock;
function Init_Mutex (L : RTS_Lock_Ptr; Prio : Any_Priority) return C.int;
-- Initialize the mutex L. If Ceiling_Support is True, then set the ceiling
-- to Prio. Returns 0 for success, or ENOMEM for out-of-memory.
-------------------
-- Abort_Handler --
-------------------
procedure Abort_Handler (signo : Signal) is
pragma Unreferenced (signo);
Self_Id : constant Task_Id := Self;
Result : 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);
end Lock_RTS;
----------------
-- Unlock_RTS --
----------------
procedure Unlock_RTS is
begin
Unlock (Single_RTS_Lock'Access);
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;
----------------
-- Init_Mutex --
----------------
function Init_Mutex (L : RTS_Lock_Ptr; Prio : Any_Priority) return C.int is
Mutex_Attr : aliased pthread_mutexattr_t;
Result, Result_2 : C.int;
begin
Result := pthread_mutexattr_init (Mutex_Attr'Access);
pragma Assert (Result in 0 | ENOMEM);
if Result = ENOMEM then
return Result;
end if;
if Ceiling_Support then
Result := pthread_mutexattr_setprotocol
(Mutex_Attr'Access, PTHREAD_PRIO_PROTECT);
pragma Assert (Result = 0);
Result := pthread_mutexattr_setprioceiling
(Mutex_Attr'Access, Prio_To_Linux_Prio (Prio));
pragma Assert (Result = 0);
elsif Locking_Policy = 'I' then
Result := pthread_mutexattr_setprotocol
(Mutex_Attr'Access, PTHREAD_PRIO_INHERIT);
pragma Assert (Result = 0);
end if;
Result := pthread_mutex_init (L, Mutex_Attr'Access);
pragma Assert (Result in 0 | ENOMEM);
Result_2 := pthread_mutexattr_destroy (Mutex_Attr'Access);
pragma Assert (Result_2 = 0);
return Result; -- of pthread_mutex_init, not pthread_mutexattr_destroy
end Init_Mutex;
---------------------
-- 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 : Any_Priority;
L : not null access Lock)
is
begin
if Locking_Policy = 'R' then
declare
RWlock_Attr : aliased pthread_rwlockattr_t;
Result : 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 in 0 | ENOMEM);
if Result = ENOMEM then
raise Storage_Error with "Failed to allocate a lock";
end if;
end;
else
if Init_Mutex (L.WO'Access, Prio) = ENOMEM then
raise Storage_Error with "Failed to allocate a lock";
end if;
end if;
end Initialize_Lock;
procedure Initialize_Lock
(L : not null access RTS_Lock; Level : Lock_Level)
is
pragma Unreferenced (Level);
begin
if Init_Mutex (L.all'Access, Any_Priority'Last) = ENOMEM then
raise Storage_Error with "Failed to allocate a lock";
end if;
end Initialize_Lock;
-------------------
-- Finalize_Lock --
-------------------
procedure Finalize_Lock (L : not null access Lock) is
Result : 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 : 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 : 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;
-- The cause of EINVAL is a priority ceiling violation
pragma Assert (Result in 0 | EINVAL);
Ceiling_Violation := Result = EINVAL;
end Write_Lock;
procedure Write_Lock (L : not null access RTS_Lock) is
Result : C.int;
begin
Result := pthread_mutex_lock (L);
pragma Assert (Result = 0);
end Write_Lock;
procedure Write_Lock (T : Task_Id) is
Result : C.int;
begin
Result := pthread_mutex_lock (T.Common.LL.L'Access);
pragma Assert (Result = 0);
end Write_Lock;
---------------
-- Read_Lock --
---------------
procedure Read_Lock
(L : not null access Lock;
Ceiling_Violation : out Boolean)
is
Result : 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;
-- The cause of EINVAL is a priority ceiling violation
pragma Assert (Result in 0 | EINVAL);
Ceiling_Violation := Result = EINVAL;
end Read_Lock;
------------
-- Unlock --
------------
procedure Unlock (L : not null access Lock) is
Result : 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) is
Result : C.int;
begin
Result := pthread_mutex_unlock (L);
pragma Assert (Result = 0);
end Unlock;
procedure Unlock (T : Task_Id) is
Result : C.int;
begin
Result := pthread_mutex_unlock (T.Common.LL.L'Access);
pragma Assert (Result = 0);
end Unlock;
-----------------
-- Set_Ceiling --
-----------------
-- Dynamic priority ceilings are not supported by the underlying system
procedure Set_Ceiling
(L : not null access Lock;
Prio : 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 : C.int;
begin
pragma Assert (Self_ID = Self);
Result :=
pthread_cond_wait
(cond => Self_ID.Common.LL.CV'Access,
mutex => Self_ID.Common.LL.L'Access);
-- EINTR is not considered a failure
pragma Assert (Result in 0 | 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) renames Monotonic.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) renames Monotonic.Timed_Delay;
---------------------
-- Monotonic_Clock --
---------------------
function Monotonic_Clock return Duration renames Monotonic.Monotonic_Clock;
-------------------
-- RT_Resolution --
-------------------
function RT_Resolution return Duration renames Monotonic.RT_Resolution;
------------
-- Wakeup --
------------
procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
pragma Unreferenced (Reason);
Result : 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 : 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 : Any_Priority;
Loss_Of_Inheritance : Boolean := False)
is
pragma Unreferenced (Loss_Of_Inheritance);
Result : C.int;
Param : aliased struct_sched_param;
function Get_Policy (Prio : 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;
Param.sched_priority := Prio_To_Linux_Prio (Prio);
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 in 0 | EPERM | EINVAL);
end Set_Priority;
------------------
-- Get_Priority --
------------------
function Get_Priority (T : Task_Id) return 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;
-- Set thread name to ease debugging. If the name of the task is
-- "foreign thread" (as set by Register_Foreign_Thread) retrieve
-- the name of the thread and update the name of the task instead.
if Self_ID.Common.Task_Image_Len = 14
and then Self_ID.Common.Task_Image (1 .. 14) = "foreign thread"
then
declare
Thread_Name : String (1 .. 16);
-- PR_GET_NAME returns a string of up to 16 bytes
Len : Natural := 0;
-- Length of the task name contained in Task_Name
Result : C.int;
-- Result from the prctl call
begin
Result := prctl (PR_GET_NAME, unsigned_long (Thread_Name'Address));
pragma Assert (Result = 0);
-- Find the length of the given name
for J in Thread_Name'Range loop
if Thread_Name (J) /= ASCII.NUL then
Len := Len + 1;
else
exit;
end if;
end loop;
-- Cover the odd situation where someone decides to change
-- Parameters.Max_Task_Image_Length to less than 16 characters.
if Len > Parameters.Max_Task_Image_Length then
Len := Parameters.Max_Task_Image_Length;
end if;
-- Copy the name of the thread to the task's ATCB
Self_ID.Common.Task_Image (1 .. Len) := Thread_Name (1 .. Len);
Self_ID.Common.Task_Image_Len := Len;
end;
elsif Self_ID.Common.Task_Image_Len > 0 then
declare
Task_Name : String (1 .. Parameters.Max_Task_Image_Length + 1);
Result : C.int;
begin
Task_Name (1 .. Self_ID.Common.Task_Image_Len) :=
Self_ID.Common.Task_Image (1 .. Self_ID.Common.Task_Image_Len);
Task_Name (Self_ID.Common.Task_Image_Len + 1) := ASCII.NUL;
Result := prctl (PR_SET_NAME, unsigned_long (Task_Name'Address));
pragma Assert (Result = 0);
end;
end if;
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 : 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
Result : C.int;
Cond_Attr : aliased pthread_condattr_t;
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 Init_Mutex (Self_ID.Common.LL.L'Access, Any_Priority'Last) /= 0 then
Succeeded := False;
return;
end if;
Result := pthread_condattr_init (Cond_Attr'Access);
pragma Assert (Result in 0 | ENOMEM);
if Result = 0 then
Result := GNAT_pthread_condattr_setup (Cond_Attr'Access);
pragma Assert (Result = 0);
Result :=
pthread_cond_init
(Self_ID.Common.LL.CV'Access, Cond_Attr'Access);
pragma Assert (Result in 0 | ENOMEM);
end if;
if Result = 0 then
Succeeded := True;
else
Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
pragma Assert (Result = 0);
Succeeded := False;
end if;
Result := pthread_condattr_destroy (Cond_Attr'Access);
pragma Assert (Result = 0);
end Initialize_TCB;
-----------------
-- Create_Task --
-----------------
procedure Create_Task
(T : Task_Id;
Wrapper : System.Address;
Stack_Size : System.Parameters.Size_Type;
Priority : Any_Priority;
Succeeded : out Boolean)
is
Thread_Attr : aliased pthread_attr_t;
Adjusted_Stack_Size : C.size_t;
Result : C.int;
use type Multiprocessors.CPU_Range, Interfaces.C.size_t;
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 /= 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 := C.size_t (Stack_Size + Alternate_Stack_Size);
Result := pthread_attr_init (Thread_Attr'Access);
pragma Assert (Result in 0 | ENOMEM);
if Result /= 0 then
Succeeded := False;
return;
end if;
Result :=
pthread_attr_setstacksize (Thread_Attr'Access, Adjusted_Stack_Size);
pragma Assert (Result = 0);
Result :=
pthread_attr_setdetachstate
(Thread_Attr'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 = Null_Address then
null;
-- Support is available
elsif T.Common.Base_CPU /= Multiprocessors.Not_A_Specific_CPU then
declare
CPUs : constant size_t :=
C.size_t (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 (Thread_Attr'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
(Thread_Attr'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 :=
C.size_t (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 (Thread_Attr'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,
Thread_Attr'Access,
Thread_Body_Access (Wrapper),
To_Address (T));
pragma Assert (Result in 0 | EAGAIN | ENOMEM);
if Result /= 0 then
Succeeded := False;
Result := pthread_attr_destroy (Thread_Attr'Access);
pragma Assert (Result = 0);
return;
end if;
Succeeded := True;
Result := pthread_attr_destroy (Thread_Attr'Access);
pragma Assert (Result = 0);
Set_Priority (T, Priority);
end Create_Task;
------------------
-- Finalize_TCB --
------------------
procedure Finalize_TCB (T : Task_Id) is
Result : C.int;
begin
Result := pthread_mutex_destroy (T.Common.LL.L'Access);
pragma Assert (Result = 0);
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;
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 : C.int;
ESRCH : constant := 3; -- No such process
-- It can happen that T has already vanished, in which case pthread_kill
-- returns ESRCH, so we don't consider that to be an error.
begin
if Abort_Handler_Installed then
Result :=
pthread_kill
(T.Common.LL.Thread,
Signal (System.Interrupt_Management.Abort_Task_Interrupt));
pragma Assert (Result in 0 | ESRCH);
end if;
end Abort_Task;
----------------
-- Initialize --
----------------
procedure Initialize (S : in out Suspension_Object) is
Result : 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 in 0 | 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 in 0 | 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 : 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 : 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 : 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 : 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 in 0 | 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 : 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)
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 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 /= Null_Address
and then T.Common.LL.Thread /= Null_Thread_Id
then
declare
CPUs : constant size_t :=
C.size_t (Multiprocessors.Number_Of_CPUs);
CPU_Set : cpu_set_t_ptr := null;
Size : constant size_t := CPU_ALLOC_SIZE (CPUs);
Result : 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
if T.Common.Domain (Proc) then
System.OS_Interface.CPU_SET (int (Proc), Size, CPU_Set);
end if;
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;