File : s-tporft.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
4 -- --
5 -- SYSTEM.TASK_PRIMITIVES.OPERATIONS.REGISTER_FOREIGN_THREAD --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 2002-2014, 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 -- --
19 -- --
20 -- --
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 with System.Task_Info;
33 -- Use for Unspecified_Task_Info
34
35 with System.Soft_Links;
36 -- used to initialize TSD for a C thread, in function Self
37
38 with System.Multiprocessors;
39
40 separate (System.Task_Primitives.Operations)
41 function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id is
42 Local_ATCB : aliased Ada_Task_Control_Block (0);
43 Self_Id : Task_Id;
44 Succeeded : Boolean;
45
46 begin
47 -- This section is tricky. We must not call anything that might require
48 -- an ATCB, until the new ATCB is in place. In order to get an ATCB
49 -- immediately, we fake one, so that it is then possible to e.g allocate
50 -- memory (which might require accessing self).
51
52 -- Record this as the Task_Id for the thread
53
54 Local_ATCB.Common.LL.Thread := Thread;
55 Local_ATCB.Common.Current_Priority := System.Priority'First;
56 Specific.Set (Local_ATCB'Unchecked_Access);
57
58 -- It is now safe to use an allocator
59
60 Self_Id := new Ada_Task_Control_Block (0);
61
62 -- Finish initialization
63
64 Lock_RTS;
65 System.Tasking.Initialize_ATCB
66 (Self_Id, null, Null_Address, Null_Task,
67 Foreign_Task_Elaborated'Access,
68 System.Priority'First, System.Multiprocessors.Not_A_Specific_CPU, null,
69 Task_Info.Unspecified_Task_Info, 0, Self_Id, Succeeded);
70 Unlock_RTS;
71 pragma Assert (Succeeded);
72
73 Self_Id.Master_of_Task := 0;
74 Self_Id.Master_Within := Self_Id.Master_of_Task + 1;
75
76 for L in Self_Id.Entry_Calls'Range loop
77 Self_Id.Entry_Calls (L).Self := Self_Id;
78 Self_Id.Entry_Calls (L).Level := L;
79 end loop;
80
81 Self_Id.Common.State := Runnable;
82 Self_Id.Awake_Count := 1;
83
84 Self_Id.Common.Task_Image (1 .. 14) := "foreign thread";
85 Self_Id.Common.Task_Image_Len := 14;
86
87 -- Since this is not an ordinary Ada task, we will start out undeferred
88
89 Self_Id.Deferral_Level := 0;
90
91 -- We do not provide an alternate stack for foreign threads
92
93 Self_Id.Common.Task_Alternate_Stack := Null_Address;
94
95 System.Soft_Links.Create_TSD (Self_Id.Common.Compiler_Data);
96
97 Enter_Task (Self_Id);
98
99 return Self_Id;
100 end Register_Foreign_Thread;