File : s-taspri-linux-xenomai.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) 1991-1994, Florida State University --
10 -- Copyright (C) 1995-2014, AdaCore --
11 -- --
12 -- GNAT is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 3, or (at your option) any later ver- --
15 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. --
18 -- --
19 -- --
20 -- --
21 -- --
22 -- --
23 -- You should have received a copy of the GNU General Public License and --
24 -- a copy of the GCC Runtime Library Exception along with this program; --
25 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
26 -- <http://www.gnu.org/licenses/>. --
27 -- --
28 -- GNARL was developed by the GNARL team at Florida State University. --
29 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
30 -- --
31 ------------------------------------------------------------------------------
32
33 -- This is a GNU/Linux (Xenomai) version of this package
34
35 pragma Polling (Off);
36 -- Turn off polling, we do not want ATC polling to take place during tasking
37 -- operations. It causes infinite loops and other problems.
38
39 with System.OS_Interface;
40
41 package System.Task_Primitives is
42 pragma Preelaborate;
43
44 type Lock is limited private;
45 -- Should be used for implementation of protected objects
46
47 type RTS_Lock is limited private;
48 -- Should be used inside the runtime system. The difference between Lock
49 -- and the RTS_Lock is that the later one serves only as a semaphore so
50 -- that do not check for ceiling violations.
51
52 type Suspension_Object is limited private;
53 -- Should be used for the implementation of Ada.Synchronous_Task_Control
54
55 type Task_Body_Access is access procedure;
56 -- Pointer to the task body's entry point (or possibly a wrapper declared
57 -- local to the GNARL).
58
59 type Private_Data is limited private;
60 -- Any information that the GNULLI needs maintained on a per-task basis.
61 -- A component of this type is guaranteed to be included in the
62 -- Ada_Task_Control_Block.
63
64 subtype Task_Address is System.Address;
65 Task_Address_Size : constant := Standard'Address_Size;
66 -- Type used for task addresses and its size
67
68 Alternate_Stack_Size : constant := System.OS_Interface.Alternate_Stack_Size;
69 -- Import value from System.OS_Interface
70
71 private
72
73 type Lock is new System.OS_Interface.thread_mutex_t;
74 type RTS_Lock is new System.OS_Interface.thread_mutex_t;
75
76 type Suspension_Object is record
77 State : Boolean;
78 pragma Atomic (State);
79 -- Boolean that indicates whether the object is open. This field is
80 -- marked Atomic to ensure that we can read its value without locking
81 -- the access to the Suspension_Object.
82
83 Waiting : Boolean;
84 -- Flag showing if there is a task already suspended on this object
85
86 L : aliased System.OS_Interface.thread_mutex_t;
87 -- Protection for ensuring mutual exclusion on the Suspension_Object
88
89 CV : aliased System.OS_Interface.thread_cond_t;
90 -- Condition variable used to queue threads until condition is signaled
91 end record;
92
93 type Private_Data is limited record
94 Thread : aliased System.OS_Interface.thread_t;
95 pragma Atomic (Thread);
96 -- Thread field may be updated by two different threads of control.
97 -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
98 -- value (thr_self value). We do not want to use lock on those
99 -- operations and the only thing we have to make sure is that they are
100 -- updated in atomic fashion.
101
102 LWP : aliased System.Address;
103 -- The purpose of this field is to provide a better tasking support on
104 -- gdb. The order of the two first fields (Thread and LWP) is important.
105 -- On targets where lwp is not relevant, this is equivalent to Thread.
106
107 PThread : aliased System.OS_Interface.pthread_t;
108 -- POSIX thread identifier needed for POSIX signal handling
109
110 CV : aliased System.OS_Interface.thread_cond_t;
111 -- Used for conditional and timed waits
112
113 L : aliased RTS_Lock;
114 -- Protection for all components is lock L
115 end record;
116
117 end System.Task_Primitives;