gcc/ada/libgnarl/s-taspri__vxworks.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                  GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                --
   4 --                                                                          --
   5 --                 S Y S T E M . T A S K _ P R I M I T I V E S              --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --          Copyright (C) 2001-2023, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNARL was developed by the GNARL team at Florida State University.       --
  28 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This is a VxWorks version of this package
  33
  34 with System.OS_Interface;
  35
  36 package System.Task_Primitives is
  37    pragma Preelaborate;
  38
  39    type Lock is limited private;
  40    --  Should be used for implementation of protected objects
  41
  42    type RTS_Lock is limited private;
  43    --  Should be used inside the runtime system. The difference between Lock
  44    --  and the RTS_Lock is that the later one serves only as a semaphore so
  45    --  that do not check for ceiling violations.
  46
  47    type Suspension_Object is limited private;
  48    --  Should be used for the implementation of Ada.Synchronous_Task_Control
  49
  50    type Task_Body_Access is access procedure;
  51    --  Pointer to the task body's entry point (or possibly a wrapper
  52    --  declared local to the GNARL).
  53
  54    type Private_Data is limited private;
  55    --  Any information that the GNULLI needs maintained on a per-task basis.
  56    --  A component of this type is guaranteed to be included in the
  57    --  Ada_Task_Control_Block.
  58
  59    subtype Task_Address is System.Address;
  60    Task_Address_Size : constant := Standard'Address_Size;
  61    --  Type used for task addresses and its size
  62
  63    Alternate_Stack_Size : constant := 0;
  64    --  No alternate signal stack is used on this platform
  65
  66 private
  67
  68    type Priority_Type is (Prio_None, Prio_Protect, Prio_Inherit);
  69
  70    type Lock is record
  71       Mutex    : System.OS_Interface.SEM_ID;
  72       Protocol : Priority_Type;
  73
  74       Prio_Ceiling : System.OS_Interface.int;
  75       --  Priority ceiling of lock
  76    end record;
  77
  78    type RTS_Lock is new Lock;
  79
  80    type Suspension_Object is record
  81       State : Boolean;
  82       pragma Atomic (State);
  83       --  Boolean that indicates whether the object is open. This field is
  84       --  marked Atomic to ensure that we can read its value without locking
  85       --  the access to the Suspension_Object.
  86
  87       Waiting : Boolean;
  88       --  Flag showing if there is a task already suspended on this object
  89
  90       L : aliased System.OS_Interface.SEM_ID;
  91       --  Protection for ensuring mutual exclusion on the Suspension_Object
  92
  93       CV : aliased System.OS_Interface.SEM_ID;
  94       --  Condition variable used to queue threads until condition is signaled
  95    end record;
  96
  97    type Private_Data is limited record
  98       Thread : aliased System.OS_Interface.t_id := 0;
  99       pragma Atomic (Thread);
 100       --  Thread field may be updated by two different threads of control.
 101       --  (See, Enter_Task and Create_Task in s-taprop.adb).
 102       --  They put the same value (thr_self value). We do not want to
 103       --  use lock on those operations and the only thing we have to
 104       --  make sure is that they are updated in atomic fashion.
 105
 106       LWP : aliased System.OS_Interface.t_id := 0;
 107       --  The purpose of this field is to provide a better tasking support on
 108       --  gdb. The order of the two first fields (Thread and LWP) is important.
 109       --  On targets where lwp is not relevant, this is equivalent to Thread.
 110
 111       CV : aliased System.OS_Interface.SEM_ID;
 112
 113       L  : aliased RTS_Lock;
 114       --  Protection for all components is lock L
 115    end record;
 116
 117 end System.Task_Primitives;