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2013-03-08 François Dumont <fdumont@gcc.gnu.org>
[official-gcc.git] / gcc / ada / s-taprop-solaris.adb
blob92088e10cb4b02a41ef394973cb2e67c872269dd
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 . O P E R A T I O N S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2011, 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 Solaris (native) version of this package
33
34 -- This package contains all the GNULL primitives that interface directly with
35 -- the underlying OS.
36
37 pragma Polling (Off);
38 -- Turn off polling, we do not want ATC polling to take place during tasking
39 -- operations. It causes infinite loops and other problems.
40
41 with Interfaces.C;
42
43 with System.Multiprocessors;
44 with System.Tasking.Debug;
45 with System.Interrupt_Management;
46 with System.OS_Constants;
47 with System.OS_Primitives;
48 with System.Task_Info;
49
50 pragma Warnings (Off);
51 with System.OS_Lib;
52 pragma Warnings (On);
53
54 with System.Soft_Links;
55 -- We use System.Soft_Links instead of System.Tasking.Initialization
56 -- because the later is a higher level package that we shouldn't depend on.
57 -- For example when using the restricted run time, it is replaced by
58 -- System.Tasking.Restricted.Stages.
59
60 package body System.Task_Primitives.Operations is
61
62 package OSC renames System.OS_Constants;
63 package SSL renames System.Soft_Links;
64
65 use System.Tasking.Debug;
66 use System.Tasking;
67 use Interfaces.C;
68 use System.OS_Interface;
69 use System.Parameters;
70 use System.OS_Primitives;
71
72 ----------------
73 -- Local Data --
74 ----------------
75
76 -- The following are logically constants, but need to be initialized
77 -- at run time.
78
79 Environment_Task_Id : Task_Id;
80 -- A variable to hold Task_Id for the environment task.
81 -- If we use this variable to get the Task_Id, we need the following
82 -- ATCB_Key only for non-Ada threads.
83
84 Unblocked_Signal_Mask : aliased sigset_t;
85 -- The set of signals that should unblocked in all tasks
86
87 ATCB_Key : aliased thread_key_t;
88 -- Key used to find the Ada Task_Id associated with a thread,
89 -- at least for C threads unknown to the Ada run-time system.
90
91 Single_RTS_Lock : aliased RTS_Lock;
92 -- This is a lock to allow only one thread of control in the RTS at
93 -- a time; it is used to execute in mutual exclusion from all other tasks.
94 -- Used mainly in Single_Lock mode, but also to protect All_Tasks_List
95
96 Next_Serial_Number : Task_Serial_Number := 100;
97 -- We start at 100, to reserve some special values for
98 -- using in error checking.
99 -- The following are internal configuration constants needed.
100
101 Abort_Handler_Installed : Boolean := False;
102 -- True if a handler for the abort signal is installed
103
104 Null_Thread_Id : constant Thread_Id := Thread_Id'Last;
105 -- Constant to indicate that the thread identifier has not yet been
106 -- initialized.
107
108 ----------------------
109 -- Priority Support --
110 ----------------------
111
112 Priority_Ceiling_Emulation : constant Boolean := True;
113 -- controls whether we emulate priority ceiling locking
114
115 -- To get a scheduling close to annex D requirements, we use the real-time
116 -- class provided for LWPs and map each task/thread to a specific and
117 -- unique LWP (there is 1 thread per LWP, and 1 LWP per thread).
118
119 -- The real time class can only be set when the process has root
120 -- privileges, so in the other cases, we use the normal thread scheduling
121 -- and priority handling.
122
123 Using_Real_Time_Class : Boolean := False;
124 -- indicates whether the real time class is being used (i.e. the process
125 -- has root privileges).
126
127 Prio_Param : aliased struct_pcparms;
128 -- Hold priority info (Real_Time) initialized during the package
129 -- elaboration.
130
131 -----------------------------------
132 -- External Configuration Values --
133 -----------------------------------
134
135 Time_Slice_Val : Integer;
136 pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
137
138 Locking_Policy : Character;
139 pragma Import (C, Locking_Policy, "__gl_locking_policy");
140
141 Dispatching_Policy : Character;
142 pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
143
144 Foreign_Task_Elaborated : aliased Boolean := True;
145 -- Used to identified fake tasks (i.e., non-Ada Threads)
146
147 -----------------------
148 -- Local Subprograms --
149 -----------------------
150
151 function sysconf (name : System.OS_Interface.int) return processorid_t;
152 pragma Import (C, sysconf, "sysconf");
153
154 SC_NPROCESSORS_CONF : constant System.OS_Interface.int := 14;
155
156 function Num_Procs
157 (name : System.OS_Interface.int := SC_NPROCESSORS_CONF)
158 return processorid_t renames sysconf;
159
160 procedure Abort_Handler
161 (Sig : Signal;
162 Code : not null access siginfo_t;
163 Context : not null access ucontext_t);
164 -- Target-dependent binding of inter-thread Abort signal to
165 -- the raising of the Abort_Signal exception.
166 -- See also comments in 7staprop.adb
167
168 ------------
169 -- Checks --
170 ------------
171
172 function Check_Initialize_Lock
173 (L : Lock_Ptr;
174 Level : Lock_Level) return Boolean;
175 pragma Inline (Check_Initialize_Lock);
176
177 function Check_Lock (L : Lock_Ptr) return Boolean;
178 pragma Inline (Check_Lock);
179
180 function Record_Lock (L : Lock_Ptr) return Boolean;
181 pragma Inline (Record_Lock);
182
183 function Check_Sleep (Reason : Task_States) return Boolean;
184 pragma Inline (Check_Sleep);
185
186 function Record_Wakeup
187 (L : Lock_Ptr;
188 Reason : Task_States) return Boolean;
189 pragma Inline (Record_Wakeup);
190
191 function Check_Wakeup
192 (T : Task_Id;
193 Reason : Task_States) return Boolean;
194 pragma Inline (Check_Wakeup);
195
196 function Check_Unlock (L : Lock_Ptr) return Boolean;
197 pragma Inline (Check_Unlock);
198
199 function Check_Finalize_Lock (L : Lock_Ptr) return Boolean;
200 pragma Inline (Check_Finalize_Lock);
201
202 --------------------
203 -- Local Packages --
204 --------------------
205
206 package Specific is
207
208 procedure Initialize (Environment_Task : Task_Id);
209 pragma Inline (Initialize);
210 -- Initialize various data needed by this package
211
212 function Is_Valid_Task return Boolean;
213 pragma Inline (Is_Valid_Task);
214 -- Does executing thread have a TCB?
215
216 procedure Set (Self_Id : Task_Id);
217 pragma Inline (Set);
218 -- Set the self id for the current task
219
220 function Self return Task_Id;
221 pragma Inline (Self);
222 -- Return a pointer to the Ada Task Control Block of the calling task
223
224 end Specific;
225
226 package body Specific is separate;
227 -- The body of this package is target specific
228
229 ----------------------------------
230 -- ATCB allocation/deallocation --
231 ----------------------------------
232
233 package body ATCB_Allocation is separate;
234 -- The body of this package is shared across several targets
235
236 ---------------------------------
237 -- Support for foreign threads --
238 ---------------------------------
239
240 function Register_Foreign_Thread (Thread : Thread_Id) return Task_Id;
241 -- Allocate and Initialize a new ATCB for the current Thread
242
243 function Register_Foreign_Thread
244 (Thread : Thread_Id) return Task_Id is separate;
245
246 ------------
247 -- Checks --
248 ------------
249
250 Check_Count : Integer := 0;
251 Lock_Count : Integer := 0;
252 Unlock_Count : Integer := 0;
253
254 -------------------
255 -- Abort_Handler --
256 -------------------
257
258 procedure Abort_Handler
259 (Sig : Signal;
260 Code : not null access siginfo_t;
261 Context : not null access ucontext_t)
262 is
263 pragma Unreferenced (Sig);
264 pragma Unreferenced (Code);
265 pragma Unreferenced (Context);
266
267 Self_ID : constant Task_Id := Self;
268 Old_Set : aliased sigset_t;
269
270 Result : Interfaces.C.int;
271 pragma Warnings (Off, Result);
272
273 begin
274 -- It's not safe to raise an exception when using GCC ZCX mechanism.
275 -- Note that we still need to install a signal handler, since in some
276 -- cases (e.g. shutdown of the Server_Task in System.Interrupts) we
277 -- need to send the Abort signal to a task.
278
279 if ZCX_By_Default then
280 return;
281 end if;
282
283 if Self_ID.Deferral_Level = 0
284 and then Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level
285 and then not Self_ID.Aborting
286 then
287 Self_ID.Aborting := True;
288
289 -- Make sure signals used for RTS internal purpose are unmasked
290
291 Result :=
292 thr_sigsetmask
293 (SIG_UNBLOCK,
294 Unblocked_Signal_Mask'Unchecked_Access,
295 Old_Set'Unchecked_Access);
296 pragma Assert (Result = 0);
297
298 raise Standard'Abort_Signal;
299 end if;
300 end Abort_Handler;
301
302 -----------------
303 -- Stack_Guard --
304 -----------------
305
306 -- The underlying thread system sets a guard page at the
307 -- bottom of a thread stack, so nothing is needed.
308
309 procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
310 pragma Unreferenced (T);
311 pragma Unreferenced (On);
312 begin
313 null;
314 end Stack_Guard;
315
316 -------------------
317 -- Get_Thread_Id --
318 -------------------
319
320 function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
321 begin
322 return T.Common.LL.Thread;
323 end Get_Thread_Id;
324
325 ----------------
326 -- Initialize --
327 ----------------
328
329 procedure Initialize (Environment_Task : ST.Task_Id) is
330 act : aliased struct_sigaction;
331 old_act : aliased struct_sigaction;
332 Tmp_Set : aliased sigset_t;
333 Result : Interfaces.C.int;
334
335 procedure Configure_Processors;
336 -- Processors configuration
337 -- The user can specify a processor which the program should run
338 -- on to emulate a single-processor system. This can be easily
339 -- done by setting environment variable GNAT_PROCESSOR to one of
340 -- the following :
341 --
342 -- -2 : use the default configuration (run the program on all
343 -- available processors) - this is the same as having
344 -- GNAT_PROCESSOR unset
345 -- -1 : let the RTS choose one processor and run the program on
346 -- that processor
347 -- 0 .. Last_Proc : run the program on the specified processor
348 --
349 -- Last_Proc is equal to the value of the system variable
350 -- _SC_NPROCESSORS_CONF, minus one.
351
352 procedure Configure_Processors is
353 Proc_Acc : constant System.OS_Lib.String_Access :=
354 System.OS_Lib.Getenv ("GNAT_PROCESSOR");
355 Proc : aliased processorid_t; -- User processor #
356 Last_Proc : processorid_t; -- Last processor #
357
358 begin
359 if Proc_Acc.all'Length /= 0 then
360
361 -- Environment variable is defined
362
363 Last_Proc := Num_Procs - 1;
364
365 if Last_Proc /= -1 then
366 Proc := processorid_t'Value (Proc_Acc.all);
367
368 if Proc <= -2 or else Proc > Last_Proc then
369
370 -- Use the default configuration
371
372 null;
373
374 elsif Proc = -1 then
375
376 -- Choose a processor
377
378 Result := 0;
379 while Proc < Last_Proc loop
380 Proc := Proc + 1;
381 Result := p_online (Proc, PR_STATUS);
382 exit when Result = PR_ONLINE;
383 end loop;
384
385 pragma Assert (Result = PR_ONLINE);
386 Result := processor_bind (P_PID, P_MYID, Proc, null);
387 pragma Assert (Result = 0);
388
389 else
390 -- Use user processor
391
392 Result := processor_bind (P_PID, P_MYID, Proc, null);
393 pragma Assert (Result = 0);
394 end if;
395 end if;
396 end if;
397
398 exception
399 when Constraint_Error =>
400
401 -- Illegal environment variable GNAT_PROCESSOR - ignored
402
403 null;
404 end Configure_Processors;
405
406 function State
407 (Int : System.Interrupt_Management.Interrupt_ID) return Character;
408 pragma Import (C, State, "__gnat_get_interrupt_state");
409 -- Get interrupt state. Defined in a-init.c
410 -- The input argument is the interrupt number,
411 -- and the result is one of the following:
412
413 Default : constant Character := 's';
414 -- 'n' this interrupt not set by any Interrupt_State pragma
415 -- 'u' Interrupt_State pragma set state to User
416 -- 'r' Interrupt_State pragma set state to Runtime
417 -- 's' Interrupt_State pragma set state to System (use "default"
418 -- system handler)
419
420 -- Start of processing for Initialize
421
422 begin
423 Environment_Task_Id := Environment_Task;
424
425 Interrupt_Management.Initialize;
426
427 -- Prepare the set of signals that should unblocked in all tasks
428
429 Result := sigemptyset (Unblocked_Signal_Mask'Access);
430 pragma Assert (Result = 0);
431
432 for J in Interrupt_Management.Interrupt_ID loop
433 if System.Interrupt_Management.Keep_Unmasked (J) then
434 Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J));
435 pragma Assert (Result = 0);
436 end if;
437 end loop;
438
439 if Dispatching_Policy = 'F' then
440 declare
441 Result : Interfaces.C.long;
442 Class_Info : aliased struct_pcinfo;
443 Secs, Nsecs : Interfaces.C.long;
444
445 begin
446 -- If a pragma Time_Slice is specified, takes the value in account
447
448 if Time_Slice_Val > 0 then
449
450 -- Convert Time_Slice_Val (microseconds) to seconds/nanosecs
451
452 Secs := Interfaces.C.long (Time_Slice_Val / 1_000_000);
453 Nsecs :=
454 Interfaces.C.long ((Time_Slice_Val rem 1_000_000) * 1_000);
455
456 -- Otherwise, default to no time slicing (i.e run until blocked)
457
458 else
459 Secs := RT_TQINF;
460 Nsecs := RT_TQINF;
461 end if;
462
463 -- Get the real time class id
464
465 Class_Info.pc_clname (1) := 'R';
466 Class_Info.pc_clname (2) := 'T';
467 Class_Info.pc_clname (3) := ASCII.NUL;
468
469 Result := priocntl (PC_VERSION, P_LWPID, P_MYID, PC_GETCID,
470 Class_Info'Address);
471
472 -- Request the real time class
473
474 Prio_Param.pc_cid := Class_Info.pc_cid;
475 Prio_Param.rt_pri := pri_t (Class_Info.rt_maxpri);
476 Prio_Param.rt_tqsecs := Secs;
477 Prio_Param.rt_tqnsecs := Nsecs;
478
479 Result :=
480 priocntl
481 (PC_VERSION, P_LWPID, P_MYID, PC_SETPARMS, Prio_Param'Address);
482
483 Using_Real_Time_Class := Result /= -1;
484 end;
485 end if;
486
487 Specific.Initialize (Environment_Task);
488
489 -- The following is done in Enter_Task, but this is too late for the
490 -- Environment Task, since we need to call Self in Check_Locks when
491 -- the run time is compiled with assertions on.
492
493 Specific.Set (Environment_Task);
494
495 -- Initialize the lock used to synchronize chain of all ATCBs
496
497 Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
498
499 -- Make environment task known here because it doesn't go through
500 -- Activate_Tasks, which does it for all other tasks.
501
502 Known_Tasks (Known_Tasks'First) := Environment_Task;
503 Environment_Task.Known_Tasks_Index := Known_Tasks'First;
504
505 Enter_Task (Environment_Task);
506
507 Configure_Processors;
508
509 if State
510 (System.Interrupt_Management.Abort_Task_Interrupt) /= Default
511 then
512 -- Set sa_flags to SA_NODEFER so that during the handler execution
513 -- we do not change the Signal_Mask to be masked for the Abort_Signal
514 -- This is a temporary fix to the problem that the Signal_Mask is
515 -- not restored after the exception (longjmp) from the handler.
516 -- The right fix should be made in sigsetjmp so that we save
517 -- the Signal_Set and restore it after a longjmp.
518 -- In that case, this field should be changed back to 0. ???
519
520 act.sa_flags := 16;
521
522 act.sa_handler := Abort_Handler'Address;
523 Result := sigemptyset (Tmp_Set'Access);
524 pragma Assert (Result = 0);
525 act.sa_mask := Tmp_Set;
526
527 Result :=
528 sigaction
529 (Signal (System.Interrupt_Management.Abort_Task_Interrupt),
530 act'Unchecked_Access,
531 old_act'Unchecked_Access);
532 pragma Assert (Result = 0);
533 Abort_Handler_Installed := True;
534 end if;
535 end Initialize;
536
537 ---------------------
538 -- Initialize_Lock --
539 ---------------------
540
541 -- Note: mutexes and cond_variables needed per-task basis are initialized
542 -- in Initialize_TCB and the Storage_Error is handled. Other mutexes (such
543 -- as RTS_Lock, Memory_Lock...) used in RTS is initialized before any
544 -- status change of RTS. Therefore raising Storage_Error in the following
545 -- routines should be able to be handled safely.
546
547 procedure Initialize_Lock
548 (Prio : System.Any_Priority;
549 L : not null access Lock)
550 is
551 Result : Interfaces.C.int;
552
553 begin
554 pragma Assert (Check_Initialize_Lock (Lock_Ptr (L), PO_Level));
555
556 if Priority_Ceiling_Emulation then
557 L.Ceiling := Prio;
558 end if;
559
560 Result := mutex_init (L.L'Access, USYNC_THREAD, System.Null_Address);
561 pragma Assert (Result = 0 or else Result = ENOMEM);
562
563 if Result = ENOMEM then
564 raise Storage_Error with "Failed to allocate a lock";
565 end if;
566 end Initialize_Lock;
567
568 procedure Initialize_Lock
569 (L : not null access RTS_Lock;
570 Level : Lock_Level)
571 is
572 Result : Interfaces.C.int;
573
574 begin
575 pragma Assert
576 (Check_Initialize_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L)), Level));
577 Result := mutex_init (L.L'Access, USYNC_THREAD, System.Null_Address);
578 pragma Assert (Result = 0 or else Result = ENOMEM);
579
580 if Result = ENOMEM then
581 raise Storage_Error with "Failed to allocate a lock";
582 end if;
583 end Initialize_Lock;
584
585 -------------------
586 -- Finalize_Lock --
587 -------------------
588
589 procedure Finalize_Lock (L : not null access Lock) is
590 Result : Interfaces.C.int;
591 begin
592 pragma Assert (Check_Finalize_Lock (Lock_Ptr (L)));
593 Result := mutex_destroy (L.L'Access);
594 pragma Assert (Result = 0);
595 end Finalize_Lock;
596
597 procedure Finalize_Lock (L : not null access RTS_Lock) is
598 Result : Interfaces.C.int;
599 begin
600 pragma Assert (Check_Finalize_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L))));
601 Result := mutex_destroy (L.L'Access);
602 pragma Assert (Result = 0);
603 end Finalize_Lock;
604
605 ----------------
606 -- Write_Lock --
607 ----------------
608
609 procedure Write_Lock
610 (L : not null access Lock;
611 Ceiling_Violation : out Boolean)
612 is
613 Result : Interfaces.C.int;
614
615 begin
616 pragma Assert (Check_Lock (Lock_Ptr (L)));
617
618 if Priority_Ceiling_Emulation and then Locking_Policy = 'C' then
619 declare
620 Self_Id : constant Task_Id := Self;
621 Saved_Priority : System.Any_Priority;
622
623 begin
624 if Self_Id.Common.LL.Active_Priority > L.Ceiling then
625 Ceiling_Violation := True;
626 return;
627 end if;
628
629 Saved_Priority := Self_Id.Common.LL.Active_Priority;
630
631 if Self_Id.Common.LL.Active_Priority < L.Ceiling then
632 Set_Priority (Self_Id, L.Ceiling);
633 end if;
634
635 Result := mutex_lock (L.L'Access);
636 pragma Assert (Result = 0);
637 Ceiling_Violation := False;
638
639 L.Saved_Priority := Saved_Priority;
640 end;
641
642 else
643 Result := mutex_lock (L.L'Access);
644 pragma Assert (Result = 0);
645 Ceiling_Violation := False;
646 end if;
647
648 pragma Assert (Record_Lock (Lock_Ptr (L)));
649 end Write_Lock;
650
651 procedure Write_Lock
652 (L : not null access RTS_Lock;
653 Global_Lock : Boolean := False)
654 is
655 Result : Interfaces.C.int;
656 begin
657 if not Single_Lock or else Global_Lock then
658 pragma Assert (Check_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L))));
659 Result := mutex_lock (L.L'Access);
660 pragma Assert (Result = 0);
661 pragma Assert (Record_Lock (To_Lock_Ptr (RTS_Lock_Ptr (L))));
662 end if;
663 end Write_Lock;
664
665 procedure Write_Lock (T : Task_Id) is
666 Result : Interfaces.C.int;
667 begin
668 if not Single_Lock then
669 pragma Assert (Check_Lock (To_Lock_Ptr (T.Common.LL.L'Access)));
670 Result := mutex_lock (T.Common.LL.L.L'Access);
671 pragma Assert (Result = 0);
672 pragma Assert (Record_Lock (To_Lock_Ptr (T.Common.LL.L'Access)));
673 end if;
674 end Write_Lock;
675
676 ---------------
677 -- Read_Lock --
678 ---------------
679
680 procedure Read_Lock
681 (L : not null access Lock;
682 Ceiling_Violation : out Boolean) is
683 begin
684 Write_Lock (L, Ceiling_Violation);
685 end Read_Lock;
686
687 ------------
688 -- Unlock --
689 ------------
690
691 procedure Unlock (L : not null access Lock) is
692 Result : Interfaces.C.int;
693
694 begin
695 pragma Assert (Check_Unlock (Lock_Ptr (L)));
696
697 if Priority_Ceiling_Emulation and then Locking_Policy = 'C' then
698 declare
699 Self_Id : constant Task_Id := Self;
700
701 begin
702 Result := mutex_unlock (L.L'Access);
703 pragma Assert (Result = 0);
704
705 if Self_Id.Common.LL.Active_Priority > L.Saved_Priority then
706 Set_Priority (Self_Id, L.Saved_Priority);
707 end if;
708 end;
709 else
710 Result := mutex_unlock (L.L'Access);
711 pragma Assert (Result = 0);
712 end if;
713 end Unlock;
714
715 procedure Unlock
716 (L : not null access RTS_Lock;
717 Global_Lock : Boolean := False)
718 is
719 Result : Interfaces.C.int;
720 begin
721 if not Single_Lock or else Global_Lock then
722 pragma Assert (Check_Unlock (To_Lock_Ptr (RTS_Lock_Ptr (L))));
723 Result := mutex_unlock (L.L'Access);
724 pragma Assert (Result = 0);
725 end if;
726 end Unlock;
727
728 procedure Unlock (T : Task_Id) is
729 Result : Interfaces.C.int;
730 begin
731 if not Single_Lock then
732 pragma Assert (Check_Unlock (To_Lock_Ptr (T.Common.LL.L'Access)));
733 Result := mutex_unlock (T.Common.LL.L.L'Access);
734 pragma Assert (Result = 0);
735 end if;
736 end Unlock;
737
738 -----------------
739 -- Set_Ceiling --
740 -----------------
741
742 -- Dynamic priority ceilings are not supported by the underlying system
743
744 procedure Set_Ceiling
745 (L : not null access Lock;
746 Prio : System.Any_Priority)
747 is
748 pragma Unreferenced (L, Prio);
749 begin
750 null;
751 end Set_Ceiling;
752
753 -- For the time delay implementation, we need to make sure we
754 -- achieve following criteria:
755
756 -- 1) We have to delay at least for the amount requested.
757 -- 2) We have to give up CPU even though the actual delay does not
758 -- result in blocking.
759 -- 3) Except for restricted run-time systems that do not support
760 -- ATC or task abort, the delay must be interrupted by the
761 -- abort_task operation.
762 -- 4) The implementation has to be efficient so that the delay overhead
763 -- is relatively cheap.
764 -- (1)-(3) are Ada requirements. Even though (2) is an Annex-D
765 -- requirement we still want to provide the effect in all cases.
766 -- The reason is that users may want to use short delays to implement
767 -- their own scheduling effect in the absence of language provided
768 -- scheduling policies.
769
770 ---------------------
771 -- Monotonic_Clock --
772 ---------------------
773
774 function Monotonic_Clock return Duration is
775 TS : aliased timespec;
776 Result : Interfaces.C.int;
777 begin
778 Result := clock_gettime (OSC.CLOCK_RT_Ada, TS'Unchecked_Access);
779 pragma Assert (Result = 0);
780 return To_Duration (TS);
781 end Monotonic_Clock;
782
783 -------------------
784 -- RT_Resolution --
785 -------------------
786
787 function RT_Resolution return Duration is
788 begin
789 return 10#1.0#E-6;
790 end RT_Resolution;
791
792 -----------
793 -- Yield --
794 -----------
795
796 procedure Yield (Do_Yield : Boolean := True) is
797 begin
798 if Do_Yield then
799 System.OS_Interface.thr_yield;
800 end if;
801 end Yield;
802
803 -----------
804 -- Self ---
805 -----------
806
807 function Self return Task_Id renames Specific.Self;
808
809 ------------------
810 -- Set_Priority --
811 ------------------
812
813 procedure Set_Priority
814 (T : Task_Id;
815 Prio : System.Any_Priority;
816 Loss_Of_Inheritance : Boolean := False)
817 is
818 pragma Unreferenced (Loss_Of_Inheritance);
819
820 Result : Interfaces.C.int;
821 pragma Unreferenced (Result);
822
823 Param : aliased struct_pcparms;
824
825 use Task_Info;
826
827 begin
828 T.Common.Current_Priority := Prio;
829
830 if Priority_Ceiling_Emulation then
831 T.Common.LL.Active_Priority := Prio;
832 end if;
833
834 if Using_Real_Time_Class then
835 Param.pc_cid := Prio_Param.pc_cid;
836 Param.rt_pri := pri_t (Prio);
837 Param.rt_tqsecs := Prio_Param.rt_tqsecs;
838 Param.rt_tqnsecs := Prio_Param.rt_tqnsecs;
839
840 Result := Interfaces.C.int (
841 priocntl (PC_VERSION, P_LWPID, T.Common.LL.LWP, PC_SETPARMS,
842 Param'Address));
843
844 else
845 if T.Common.Task_Info /= null
846 and then not T.Common.Task_Info.Bound_To_LWP
847 then
848 -- The task is not bound to a LWP, so use thr_setprio
849
850 Result :=
851 thr_setprio (T.Common.LL.Thread, Interfaces.C.int (Prio));
852
853 else
854 -- The task is bound to a LWP, use priocntl
855 -- ??? TBD
856
857 null;
858 end if;
859 end if;
860 end Set_Priority;
861
862 ------------------
863 -- Get_Priority --
864 ------------------
865
866 function Get_Priority (T : Task_Id) return System.Any_Priority is
867 begin
868 return T.Common.Current_Priority;
869 end Get_Priority;
870
871 ----------------
872 -- Enter_Task --
873 ----------------
874
875 procedure Enter_Task (Self_ID : Task_Id) is
876 begin
877 Self_ID.Common.LL.Thread := thr_self;
878 Self_ID.Common.LL.LWP := lwp_self;
879
880 Set_Task_Affinity (Self_ID);
881 Specific.Set (Self_ID);
882
883 -- We need the above code even if we do direct fetch of Task_Id in Self
884 -- for the main task on Sun, x86 Solaris and for gcc 2.7.2.
885 end Enter_Task;
886
887 -------------------
888 -- Is_Valid_Task --
889 -------------------
890
891 function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
892
893 -----------------------------
894 -- Register_Foreign_Thread --
895 -----------------------------
896
897 function Register_Foreign_Thread return Task_Id is
898 begin
899 if Is_Valid_Task then
900 return Self;
901 else
902 return Register_Foreign_Thread (thr_self);
903 end if;
904 end Register_Foreign_Thread;
905
906 --------------------
907 -- Initialize_TCB --
908 --------------------
909
910 procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
911 Result : Interfaces.C.int := 0;
912
913 begin
914 -- Give the task a unique serial number
915
916 Self_ID.Serial_Number := Next_Serial_Number;
917 Next_Serial_Number := Next_Serial_Number + 1;
918 pragma Assert (Next_Serial_Number /= 0);
919
920 Self_ID.Common.LL.Thread := Null_Thread_Id;
921
922 if not Single_Lock then
923 Result :=
924 mutex_init
925 (Self_ID.Common.LL.L.L'Access, USYNC_THREAD, System.Null_Address);
926 Self_ID.Common.LL.L.Level :=
927 Private_Task_Serial_Number (Self_ID.Serial_Number);
928 pragma Assert (Result = 0 or else Result = ENOMEM);
929 end if;
930
931 if Result = 0 then
932 Result := cond_init (Self_ID.Common.LL.CV'Access, USYNC_THREAD, 0);
933 pragma Assert (Result = 0 or else Result = ENOMEM);
934 end if;
935
936 if Result = 0 then
937 Succeeded := True;
938 else
939 if not Single_Lock then
940 Result := mutex_destroy (Self_ID.Common.LL.L.L'Access);
941 pragma Assert (Result = 0);
942 end if;
943
944 Succeeded := False;
945 end if;
946 end Initialize_TCB;
947
948 -----------------
949 -- Create_Task --
950 -----------------
951
952 procedure Create_Task
953 (T : Task_Id;
954 Wrapper : System.Address;
955 Stack_Size : System.Parameters.Size_Type;
956 Priority : System.Any_Priority;
957 Succeeded : out Boolean)
958 is
959 pragma Unreferenced (Priority);
960
961 Result : Interfaces.C.int;
962 Adjusted_Stack_Size : Interfaces.C.size_t;
963 Opts : Interfaces.C.int := THR_DETACHED;
964
965 Page_Size : constant System.Parameters.Size_Type := 4096;
966 -- This constant is for reserving extra space at the
967 -- end of the stack, which can be used by the stack
968 -- checking as guard page. The idea is that we need
969 -- to have at least Stack_Size bytes available for
970 -- actual use.
971
972 use System.Task_Info;
973 use type System.Multiprocessors.CPU_Range;
974
975 begin
976 -- Check whether both Dispatching_Domain and CPU are specified for the
977 -- task, and the CPU value is not contained within the range of
978 -- processors for the domain.
979
980 if T.Common.Domain /= null
981 and then T.Common.Base_CPU /= System.Multiprocessors.Not_A_Specific_CPU
982 and then
983 (T.Common.Base_CPU not in T.Common.Domain'Range
984 or else not T.Common.Domain (T.Common.Base_CPU))
985 then
986 Succeeded := False;
987 return;
988 end if;
989
990 Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size + Page_Size);
991
992 -- Since the initial signal mask of a thread is inherited from the
993 -- creator, and the Environment task has all its signals masked, we
994 -- do not need to manipulate caller's signal mask at this point.
995 -- All tasks in RTS will have All_Tasks_Mask initially.
996
997 if T.Common.Task_Info /= null then
998 if T.Common.Task_Info.New_LWP then
999 Opts := Opts + THR_NEW_LWP;
1000 end if;
1001
1002 if T.Common.Task_Info.Bound_To_LWP then
1003 Opts := Opts + THR_BOUND;
1004 end if;
1005
1006 else
1007 Opts := THR_DETACHED + THR_BOUND;
1008 end if;
1009
1010 -- Note: the use of Unrestricted_Access in the following call is needed
1011 -- because otherwise we have an error of getting a access-to-volatile
1012 -- value which points to a non-volatile object. But in this case it is
1013 -- safe to do this, since we know we have no problems with aliasing and
1014 -- Unrestricted_Access bypasses this check.
1015
1016 Result :=
1017 thr_create
1018 (System.Null_Address,
1019 Adjusted_Stack_Size,
1020 Thread_Body_Access (Wrapper),
1021 To_Address (T),
1022 Opts,
1023 T.Common.LL.Thread'Unrestricted_Access);
1024
1025 Succeeded := Result = 0;
1026 pragma Assert
1027 (Result = 0
1028 or else Result = ENOMEM
1029 or else Result = EAGAIN);
1030 end Create_Task;
1031
1032 ------------------
1033 -- Finalize_TCB --
1034 ------------------
1035
1036 procedure Finalize_TCB (T : Task_Id) is
1037 Result : Interfaces.C.int;
1038
1039 begin
1040 T.Common.LL.Thread := Null_Thread_Id;
1041
1042 if not Single_Lock then
1043 Result := mutex_destroy (T.Common.LL.L.L'Access);
1044 pragma Assert (Result = 0);
1045 end if;
1046
1047 Result := cond_destroy (T.Common.LL.CV'Access);
1048 pragma Assert (Result = 0);
1049
1050 if T.Known_Tasks_Index /= -1 then
1051 Known_Tasks (T.Known_Tasks_Index) := null;
1052 end if;
1053
1054 ATCB_Allocation.Free_ATCB (T);
1055 end Finalize_TCB;
1056
1057 ---------------
1058 -- Exit_Task --
1059 ---------------
1060
1061 -- This procedure must be called with abort deferred. It can no longer
1062 -- call Self or access the current task's ATCB, since the ATCB has been
1063 -- deallocated.
1064
1065 procedure Exit_Task is
1066 begin
1067 Specific.Set (null);
1068 end Exit_Task;
1069
1070 ----------------
1071 -- Abort_Task --
1072 ----------------
1073
1074 procedure Abort_Task (T : Task_Id) is
1075 Result : Interfaces.C.int;
1076 begin
1077 if Abort_Handler_Installed then
1078 pragma Assert (T /= Self);
1079 Result :=
1080 thr_kill
1081 (T.Common.LL.Thread,
1082 Signal (System.Interrupt_Management.Abort_Task_Interrupt));
1083 pragma Assert (Result = 0);
1084 end if;
1085 end Abort_Task;
1086
1087 -----------
1088 -- Sleep --
1089 -----------
1090
1091 procedure Sleep
1092 (Self_ID : Task_Id;
1093 Reason : Task_States)
1094 is
1095 Result : Interfaces.C.int;
1096
1097 begin
1098 pragma Assert (Check_Sleep (Reason));
1099
1100 if Single_Lock then
1101 Result :=
1102 cond_wait
1103 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock.L'Access);
1104 else
1105 Result :=
1106 cond_wait
1107 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L.L'Access);
1108 end if;
1109
1110 pragma Assert
1111 (Record_Wakeup (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Reason));
1112 pragma Assert (Result = 0 or else Result = EINTR);
1113 end Sleep;
1114
1115 -- Note that we are relying heavily here on GNAT representing
1116 -- Calendar.Time, System.Real_Time.Time, Duration,
1117 -- System.Real_Time.Time_Span in the same way, i.e., as a 64-bit count of
1118 -- nanoseconds.
1119
1120 -- This allows us to always pass the timeout value as a Duration
1121
1122 -- ???
1123 -- We are taking liberties here with the semantics of the delays. That is,
1124 -- we make no distinction between delays on the Calendar clock and delays
1125 -- on the Real_Time clock. That is technically incorrect, if the Calendar
1126 -- clock happens to be reset or adjusted. To solve this defect will require
1127 -- modification to the compiler interface, so that it can pass through more
1128 -- information, to tell us here which clock to use!
1129
1130 -- cond_timedwait will return if any of the following happens:
1131 -- 1) some other task did cond_signal on this condition variable
1132 -- In this case, the return value is 0
1133 -- 2) the call just returned, for no good reason
1134 -- This is called a "spurious wakeup".
1135 -- In this case, the return value may also be 0.
1136 -- 3) the time delay expires
1137 -- In this case, the return value is ETIME
1138 -- 4) this task received a signal, which was handled by some
1139 -- handler procedure, and now the thread is resuming execution
1140 -- UNIX calls this an "interrupted" system call.
1141 -- In this case, the return value is EINTR
1142
1143 -- If the cond_timedwait returns 0 or EINTR, it is still possible that the
1144 -- time has actually expired, and by chance a signal or cond_signal
1145 -- occurred at around the same time.
1146
1147 -- We have also observed that on some OS's the value ETIME will be
1148 -- returned, but the clock will show that the full delay has not yet
1149 -- expired.
1150
1151 -- For these reasons, we need to check the clock after return from
1152 -- cond_timedwait. If the time has expired, we will set Timedout = True.
1153
1154 -- This check might be omitted for systems on which the cond_timedwait()
1155 -- never returns early or wakes up spuriously.
1156
1157 -- Annex D requires that completion of a delay cause the task to go to the
1158 -- end of its priority queue, regardless of whether the task actually was
1159 -- suspended by the delay. Since cond_timedwait does not do this on
1160 -- Solaris, we add a call to thr_yield at the end. We might do this at the
1161 -- beginning, instead, but then the round-robin effect would not be the
1162 -- same; the delayed task would be ahead of other tasks of the same
1163 -- priority that awoke while it was sleeping.
1164
1165 -- For Timed_Sleep, we are expecting possible cond_signals to indicate
1166 -- other events (e.g., completion of a RV or completion of the abortable
1167 -- part of an async. select), we want to always return if interrupted. The
1168 -- caller will be responsible for checking the task state to see whether
1169 -- the wakeup was spurious, and to go back to sleep again in that case. We
1170 -- don't need to check for pending abort or priority change on the way in
1171 -- our out; that is the caller's responsibility.
1172
1173 -- For Timed_Delay, we are not expecting any cond_signals or other
1174 -- interruptions, except for priority changes and aborts. Therefore, we
1175 -- don't want to return unless the delay has actually expired, or the call
1176 -- has been aborted. In this case, since we want to implement the entire
1177 -- delay statement semantics, we do need to check for pending abort and
1178 -- priority changes. We can quietly handle priority changes inside the
1179 -- procedure, since there is no entry-queue reordering involved.
1180
1181 -----------------
1182 -- Timed_Sleep --
1183 -----------------
1184
1185 procedure Timed_Sleep
1186 (Self_ID : Task_Id;
1187 Time : Duration;
1188 Mode : ST.Delay_Modes;
1189 Reason : System.Tasking.Task_States;
1190 Timedout : out Boolean;
1191 Yielded : out Boolean)
1192 is
1193 Base_Time : constant Duration := Monotonic_Clock;
1194 Check_Time : Duration := Base_Time;
1195 Abs_Time : Duration;
1196 Request : aliased timespec;
1197 Result : Interfaces.C.int;
1198
1199 begin
1200 pragma Assert (Check_Sleep (Reason));
1201 Timedout := True;
1202 Yielded := False;
1203
1204 Abs_Time :=
1205 (if Mode = Relative
1206 then Duration'Min (Time, Max_Sensible_Delay) + Check_Time
1207 else Duration'Min (Check_Time + Max_Sensible_Delay, Time));
1208
1209 if Abs_Time > Check_Time then
1210 Request := To_Timespec (Abs_Time);
1211 loop
1212 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
1213
1214 if Single_Lock then
1215 Result :=
1216 cond_timedwait
1217 (Self_ID.Common.LL.CV'Access,
1218 Single_RTS_Lock.L'Access, Request'Access);
1219 else
1220 Result :=
1221 cond_timedwait
1222 (Self_ID.Common.LL.CV'Access,
1223 Self_ID.Common.LL.L.L'Access, Request'Access);
1224 end if;
1225
1226 Yielded := True;
1227
1228 Check_Time := Monotonic_Clock;
1229 exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
1230
1231 if Result = 0 or Result = EINTR then
1232
1233 -- Somebody may have called Wakeup for us
1234
1235 Timedout := False;
1236 exit;
1237 end if;
1238
1239 pragma Assert (Result = ETIME);
1240 end loop;
1241 end if;
1242
1243 pragma Assert
1244 (Record_Wakeup (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Reason));
1245 end Timed_Sleep;
1246
1247 -----------------
1248 -- Timed_Delay --
1249 -----------------
1250
1251 procedure Timed_Delay
1252 (Self_ID : Task_Id;
1253 Time : Duration;
1254 Mode : ST.Delay_Modes)
1255 is
1256 Base_Time : constant Duration := Monotonic_Clock;
1257 Check_Time : Duration := Base_Time;
1258 Abs_Time : Duration;
1259 Request : aliased timespec;
1260 Result : Interfaces.C.int;
1261 Yielded : Boolean := False;
1262
1263 begin
1264 if Single_Lock then
1265 Lock_RTS;
1266 end if;
1267
1268 Write_Lock (Self_ID);
1269
1270 Abs_Time :=
1271 (if Mode = Relative
1272 then Time + Check_Time
1273 else Duration'Min (Check_Time + Max_Sensible_Delay, Time));
1274
1275 if Abs_Time > Check_Time then
1276 Request := To_Timespec (Abs_Time);
1277 Self_ID.Common.State := Delay_Sleep;
1278
1279 pragma Assert (Check_Sleep (Delay_Sleep));
1280
1281 loop
1282 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
1283
1284 if Single_Lock then
1285 Result :=
1286 cond_timedwait
1287 (Self_ID.Common.LL.CV'Access,
1288 Single_RTS_Lock.L'Access,
1289 Request'Access);
1290 else
1291 Result :=
1292 cond_timedwait
1293 (Self_ID.Common.LL.CV'Access,
1294 Self_ID.Common.LL.L.L'Access,
1295 Request'Access);
1296 end if;
1297
1298 Yielded := True;
1299
1300 Check_Time := Monotonic_Clock;
1301 exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
1302
1303 pragma Assert
1304 (Result = 0 or else
1305 Result = ETIME or else
1306 Result = EINTR);
1307 end loop;
1308
1309 pragma Assert
1310 (Record_Wakeup
1311 (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Delay_Sleep));
1312
1313 Self_ID.Common.State := Runnable;
1314 end if;
1315
1316 Unlock (Self_ID);
1317
1318 if Single_Lock then
1319 Unlock_RTS;
1320 end if;
1321
1322 if not Yielded then
1323 thr_yield;
1324 end if;
1325 end Timed_Delay;
1326
1327 ------------
1328 -- Wakeup --
1329 ------------
1330
1331 procedure Wakeup
1332 (T : Task_Id;
1333 Reason : Task_States)
1334 is
1335 Result : Interfaces.C.int;
1336 begin
1337 pragma Assert (Check_Wakeup (T, Reason));
1338 Result := cond_signal (T.Common.LL.CV'Access);
1339 pragma Assert (Result = 0);
1340 end Wakeup;
1341
1342 ---------------------------
1343 -- Check_Initialize_Lock --
1344 ---------------------------
1345
1346 -- The following code is intended to check some of the invariant assertions
1347 -- related to lock usage, on which we depend.
1348
1349 function Check_Initialize_Lock
1350 (L : Lock_Ptr;
1351 Level : Lock_Level) return Boolean
1352 is
1353 Self_ID : constant Task_Id := Self;
1354
1355 begin
1356 -- Check that caller is abort-deferred
1357
1358 if Self_ID.Deferral_Level = 0 then
1359 return False;
1360 end if;
1361
1362 -- Check that the lock is not yet initialized
1363
1364 if L.Level /= 0 then
1365 return False;
1366 end if;
1367
1368 L.Level := Lock_Level'Pos (Level) + 1;
1369 return True;
1370 end Check_Initialize_Lock;
1371
1372 ----------------
1373 -- Check_Lock --
1374 ----------------
1375
1376 function Check_Lock (L : Lock_Ptr) return Boolean is
1377 Self_ID : constant Task_Id := Self;
1378 P : Lock_Ptr;
1379
1380 begin
1381 -- Check that the argument is not null
1382
1383 if L = null then
1384 return False;
1385 end if;
1386
1387 -- Check that L is not frozen
1388
1389 if L.Frozen then
1390 return False;
1391 end if;
1392
1393 -- Check that caller is abort-deferred
1394
1395 if Self_ID.Deferral_Level = 0 then
1396 return False;
1397 end if;
1398
1399 -- Check that caller is not holding this lock already
1400
1401 if L.Owner = To_Owner_ID (To_Address (Self_ID)) then
1402 return False;
1403 end if;
1404
1405 if Single_Lock then
1406 return True;
1407 end if;
1408
1409 -- Check that TCB lock order rules are satisfied
1410
1411 P := Self_ID.Common.LL.Locks;
1412 if P /= null then
1413 if P.Level >= L.Level
1414 and then (P.Level > 2 or else L.Level > 2)
1415 then
1416 return False;
1417 end if;
1418 end if;
1419
1420 return True;
1421 end Check_Lock;
1422
1423 -----------------
1424 -- Record_Lock --
1425 -----------------
1426
1427 function Record_Lock (L : Lock_Ptr) return Boolean is
1428 Self_ID : constant Task_Id := Self;
1429 P : Lock_Ptr;
1430
1431 begin
1432 Lock_Count := Lock_Count + 1;
1433
1434 -- There should be no owner for this lock at this point
1435
1436 if L.Owner /= null then
1437 return False;
1438 end if;
1439
1440 -- Record new owner
1441
1442 L.Owner := To_Owner_ID (To_Address (Self_ID));
1443
1444 if Single_Lock then
1445 return True;
1446 end if;
1447
1448 -- Check that TCB lock order rules are satisfied
1449
1450 P := Self_ID.Common.LL.Locks;
1451
1452 if P /= null then
1453 L.Next := P;
1454 end if;
1455
1456 Self_ID.Common.LL.Locking := null;
1457 Self_ID.Common.LL.Locks := L;
1458 return True;
1459 end Record_Lock;
1460
1461 -----------------
1462 -- Check_Sleep --
1463 -----------------
1464
1465 function Check_Sleep (Reason : Task_States) return Boolean is
1466 pragma Unreferenced (Reason);
1467
1468 Self_ID : constant Task_Id := Self;
1469 P : Lock_Ptr;
1470
1471 begin
1472 -- Check that caller is abort-deferred
1473
1474 if Self_ID.Deferral_Level = 0 then
1475 return False;
1476 end if;
1477
1478 if Single_Lock then
1479 return True;
1480 end if;
1481
1482 -- Check that caller is holding own lock, on top of list
1483
1484 if Self_ID.Common.LL.Locks /=
1485 To_Lock_Ptr (Self_ID.Common.LL.L'Access)
1486 then
1487 return False;
1488 end if;
1489
1490 -- Check that TCB lock order rules are satisfied
1491
1492 if Self_ID.Common.LL.Locks.Next /= null then
1493 return False;
1494 end if;
1495
1496 Self_ID.Common.LL.L.Owner := null;
1497 P := Self_ID.Common.LL.Locks;
1498 Self_ID.Common.LL.Locks := Self_ID.Common.LL.Locks.Next;
1499 P.Next := null;
1500 return True;
1501 end Check_Sleep;
1502
1503 -------------------
1504 -- Record_Wakeup --
1505 -------------------
1506
1507 function Record_Wakeup
1508 (L : Lock_Ptr;
1509 Reason : Task_States) return Boolean
1510 is
1511 pragma Unreferenced (Reason);
1512
1513 Self_ID : constant Task_Id := Self;
1514 P : Lock_Ptr;
1515
1516 begin
1517 -- Record new owner
1518
1519 L.Owner := To_Owner_ID (To_Address (Self_ID));
1520
1521 if Single_Lock then
1522 return True;
1523 end if;
1524
1525 -- Check that TCB lock order rules are satisfied
1526
1527 P := Self_ID.Common.LL.Locks;
1528
1529 if P /= null then
1530 L.Next := P;
1531 end if;
1532
1533 Self_ID.Common.LL.Locking := null;
1534 Self_ID.Common.LL.Locks := L;
1535 return True;
1536 end Record_Wakeup;
1537
1538 ------------------
1539 -- Check_Wakeup --
1540 ------------------
1541
1542 function Check_Wakeup
1543 (T : Task_Id;
1544 Reason : Task_States) return Boolean
1545 is
1546 Self_ID : constant Task_Id := Self;
1547
1548 begin
1549 -- Is caller holding T's lock?
1550
1551 if T.Common.LL.L.Owner /= To_Owner_ID (To_Address (Self_ID)) then
1552 return False;
1553 end if;
1554
1555 -- Are reasons for wakeup and sleep consistent?
1556
1557 if T.Common.State /= Reason then
1558 return False;
1559 end if;
1560
1561 return True;
1562 end Check_Wakeup;
1563
1564 ------------------
1565 -- Check_Unlock --
1566 ------------------
1567
1568 function Check_Unlock (L : Lock_Ptr) return Boolean is
1569 Self_ID : constant Task_Id := Self;
1570 P : Lock_Ptr;
1571
1572 begin
1573 Unlock_Count := Unlock_Count + 1;
1574
1575 if L = null then
1576 return False;
1577 end if;
1578
1579 if L.Buddy /= null then
1580 return False;
1581 end if;
1582
1583 -- Magic constant 4???
1584
1585 if L.Level = 4 then
1586 Check_Count := Unlock_Count;
1587 end if;
1588
1589 -- Magic constant 1000???
1590
1591 if Unlock_Count - Check_Count > 1000 then
1592 Check_Count := Unlock_Count;
1593 end if;
1594
1595 -- Check that caller is abort-deferred
1596
1597 if Self_ID.Deferral_Level = 0 then
1598 return False;
1599 end if;
1600
1601 -- Check that caller is holding this lock, on top of list
1602
1603 if Self_ID.Common.LL.Locks /= L then
1604 return False;
1605 end if;
1606
1607 -- Record there is no owner now
1608
1609 L.Owner := null;
1610 P := Self_ID.Common.LL.Locks;
1611 Self_ID.Common.LL.Locks := Self_ID.Common.LL.Locks.Next;
1612 P.Next := null;
1613 return True;
1614 end Check_Unlock;
1615
1616 --------------------
1617 -- Check_Finalize --
1618 --------------------
1619
1620 function Check_Finalize_Lock (L : Lock_Ptr) return Boolean is
1621 Self_ID : constant Task_Id := Self;
1622
1623 begin
1624 -- Check that caller is abort-deferred
1625
1626 if Self_ID.Deferral_Level = 0 then
1627 return False;
1628 end if;
1629
1630 -- Check that no one is holding this lock
1631
1632 if L.Owner /= null then
1633 return False;
1634 end if;
1635
1636 L.Frozen := True;
1637 return True;
1638 end Check_Finalize_Lock;
1639
1640 ----------------
1641 -- Initialize --
1642 ----------------
1643
1644 procedure Initialize (S : in out Suspension_Object) is
1645 Result : Interfaces.C.int;
1646
1647 begin
1648 -- Initialize internal state (always to zero (RM D.10(6)))
1649
1650 S.State := False;
1651 S.Waiting := False;
1652
1653 -- Initialize internal mutex
1654
1655 Result := mutex_init (S.L'Access, USYNC_THREAD, System.Null_Address);
1656 pragma Assert (Result = 0 or else Result = ENOMEM);
1657
1658 if Result = ENOMEM then
1659 raise Storage_Error with "Failed to allocate a lock";
1660 end if;
1661
1662 -- Initialize internal condition variable
1663
1664 Result := cond_init (S.CV'Access, USYNC_THREAD, 0);
1665 pragma Assert (Result = 0 or else Result = ENOMEM);
1666
1667 if Result /= 0 then
1668 Result := mutex_destroy (S.L'Access);
1669 pragma Assert (Result = 0);
1670
1671 if Result = ENOMEM then
1672 raise Storage_Error;
1673 end if;
1674 end if;
1675 end Initialize;
1676
1677 --------------
1678 -- Finalize --
1679 --------------
1680
1681 procedure Finalize (S : in out Suspension_Object) is
1682 Result : Interfaces.C.int;
1683
1684 begin
1685 -- Destroy internal mutex
1686
1687 Result := mutex_destroy (S.L'Access);
1688 pragma Assert (Result = 0);
1689
1690 -- Destroy internal condition variable
1691
1692 Result := cond_destroy (S.CV'Access);
1693 pragma Assert (Result = 0);
1694 end Finalize;
1695
1696 -------------------
1697 -- Current_State --
1698 -------------------
1699
1700 function Current_State (S : Suspension_Object) return Boolean is
1701 begin
1702 -- We do not want to use lock on this read operation. State is marked
1703 -- as Atomic so that we ensure that the value retrieved is correct.
1704
1705 return S.State;
1706 end Current_State;
1707
1708 ---------------
1709 -- Set_False --
1710 ---------------
1711
1712 procedure Set_False (S : in out Suspension_Object) is
1713 Result : Interfaces.C.int;
1714
1715 begin
1716 SSL.Abort_Defer.all;
1717
1718 Result := mutex_lock (S.L'Access);
1719 pragma Assert (Result = 0);
1720
1721 S.State := False;
1722
1723 Result := mutex_unlock (S.L'Access);
1724 pragma Assert (Result = 0);
1725
1726 SSL.Abort_Undefer.all;
1727 end Set_False;
1728
1729 --------------
1730 -- Set_True --
1731 --------------
1732
1733 procedure Set_True (S : in out Suspension_Object) is
1734 Result : Interfaces.C.int;
1735
1736 begin
1737 SSL.Abort_Defer.all;
1738
1739 Result := mutex_lock (S.L'Access);
1740 pragma Assert (Result = 0);
1741
1742 -- If there is already a task waiting on this suspension object then
1743 -- we resume it, leaving the state of the suspension object to False,
1744 -- as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
1745 -- the state to True.
1746
1747 if S.Waiting then
1748 S.Waiting := False;
1749 S.State := False;
1750
1751 Result := cond_signal (S.CV'Access);
1752 pragma Assert (Result = 0);
1753
1754 else
1755 S.State := True;
1756 end if;
1757
1758 Result := mutex_unlock (S.L'Access);
1759 pragma Assert (Result = 0);
1760
1761 SSL.Abort_Undefer.all;
1762 end Set_True;
1763
1764 ------------------------
1765 -- Suspend_Until_True --
1766 ------------------------
1767
1768 procedure Suspend_Until_True (S : in out Suspension_Object) is
1769 Result : Interfaces.C.int;
1770
1771 begin
1772 SSL.Abort_Defer.all;
1773
1774 Result := mutex_lock (S.L'Access);
1775 pragma Assert (Result = 0);
1776
1777 if S.Waiting then
1778
1779 -- Program_Error must be raised upon calling Suspend_Until_True
1780 -- if another task is already waiting on that suspension object
1781 -- (RM D.10(10)).
1782
1783 Result := mutex_unlock (S.L'Access);
1784 pragma Assert (Result = 0);
1785
1786 SSL.Abort_Undefer.all;
1787
1788 raise Program_Error;
1789
1790 else
1791 -- Suspend the task if the state is False. Otherwise, the task
1792 -- continues its execution, and the state of the suspension object
1793 -- is set to False (ARM D.10 par. 9).
1794
1795 if S.State then
1796 S.State := False;
1797 else
1798 S.Waiting := True;
1799
1800 loop
1801 -- Loop in case pthread_cond_wait returns earlier than expected
1802 -- (e.g. in case of EINTR caused by a signal).
1803
1804 Result := cond_wait (S.CV'Access, S.L'Access);
1805 pragma Assert (Result = 0 or else Result = EINTR);
1806
1807 exit when not S.Waiting;
1808 end loop;
1809 end if;
1810
1811 Result := mutex_unlock (S.L'Access);
1812 pragma Assert (Result = 0);
1813
1814 SSL.Abort_Undefer.all;
1815 end if;
1816 end Suspend_Until_True;
1817
1818 ----------------
1819 -- Check_Exit --
1820 ----------------
1821
1822 function Check_Exit (Self_ID : Task_Id) return Boolean is
1823 begin
1824 -- Check that caller is just holding Global_Task_Lock and no other locks
1825
1826 if Self_ID.Common.LL.Locks = null then
1827 return False;
1828 end if;
1829
1830 -- 2 = Global_Task_Level
1831
1832 if Self_ID.Common.LL.Locks.Level /= 2 then
1833 return False;
1834 end if;
1835
1836 if Self_ID.Common.LL.Locks.Next /= null then
1837 return False;
1838 end if;
1839
1840 -- Check that caller is abort-deferred
1841
1842 if Self_ID.Deferral_Level = 0 then
1843 return False;
1844 end if;
1845
1846 return True;
1847 end Check_Exit;
1848
1849 --------------------
1850 -- Check_No_Locks --
1851 --------------------
1852
1853 function Check_No_Locks (Self_ID : Task_Id) return Boolean is
1854 begin
1855 return Self_ID.Common.LL.Locks = null;
1856 end Check_No_Locks;
1857
1858 ----------------------
1859 -- Environment_Task --
1860 ----------------------
1861
1862 function Environment_Task return Task_Id is
1863 begin
1864 return Environment_Task_Id;
1865 end Environment_Task;
1866
1867 --------------
1868 -- Lock_RTS --
1869 --------------
1870
1871 procedure Lock_RTS is
1872 begin
1873 Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1874 end Lock_RTS;
1875
1876 ----------------
1877 -- Unlock_RTS --
1878 ----------------
1879
1880 procedure Unlock_RTS is
1881 begin
1882 Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1883 end Unlock_RTS;
1884
1885 ------------------
1886 -- Suspend_Task --
1887 ------------------
1888
1889 function Suspend_Task
1890 (T : ST.Task_Id;
1891 Thread_Self : Thread_Id) return Boolean
1892 is
1893 begin
1894 if T.Common.LL.Thread /= Thread_Self then
1895 return thr_suspend (T.Common.LL.Thread) = 0;
1896 else
1897 return True;
1898 end if;
1899 end Suspend_Task;
1900
1901 -----------------
1902 -- Resume_Task --
1903 -----------------
1904
1905 function Resume_Task
1906 (T : ST.Task_Id;
1907 Thread_Self : Thread_Id) return Boolean
1908 is
1909 begin
1910 if T.Common.LL.Thread /= Thread_Self then
1911 return thr_continue (T.Common.LL.Thread) = 0;
1912 else
1913 return True;
1914 end if;
1915 end Resume_Task;
1916
1917 --------------------
1918 -- Stop_All_Tasks --
1919 --------------------
1920
1921 procedure Stop_All_Tasks is
1922 begin
1923 null;
1924 end Stop_All_Tasks;
1925
1926 ---------------
1927 -- Stop_Task --
1928 ---------------
1929
1930 function Stop_Task (T : ST.Task_Id) return Boolean is
1931 pragma Unreferenced (T);
1932 begin
1933 return False;
1934 end Stop_Task;
1935
1936 -------------------
1937 -- Continue_Task --
1938 -------------------
1939
1940 function Continue_Task (T : ST.Task_Id) return Boolean is
1941 pragma Unreferenced (T);
1942 begin
1943 return False;
1944 end Continue_Task;
1945
1946 -----------------------
1947 -- Set_Task_Affinity --
1948 -----------------------
1949
1950 procedure Set_Task_Affinity (T : ST.Task_Id) is
1951 Result : Interfaces.C.int;
1952 Proc : processorid_t; -- User processor #
1953 Last_Proc : processorid_t; -- Last processor #
1954
1955 use System.Task_Info;
1956 use type System.Multiprocessors.CPU_Range;
1957
1958 begin
1959 -- Do nothing if the underlying thread has not yet been created. If the
1960 -- thread has not yet been created then the proper affinity will be set
1961 -- during its creation.
1962
1963 if T.Common.LL.Thread = Null_Thread_Id then
1964 null;
1965
1966 -- pragma CPU
1967
1968 elsif T.Common.Base_CPU /=
1969 System.Multiprocessors.Not_A_Specific_CPU
1970 then
1971 -- The CPU numbering in pragma CPU starts at 1 while the subprogram
1972 -- to set the affinity starts at 0, therefore we must substract 1.
1973
1974 Result :=
1975 processor_bind
1976 (P_LWPID, id_t (T.Common.LL.LWP),
1977 processorid_t (T.Common.Base_CPU) - 1, null);
1978 pragma Assert (Result = 0);
1979
1980 -- Task_Info
1981
1982 elsif T.Common.Task_Info /= null then
1983 if T.Common.Task_Info.New_LWP
1984 and then T.Common.Task_Info.CPU /= CPU_UNCHANGED
1985 then
1986 Last_Proc := Num_Procs - 1;
1987
1988 if T.Common.Task_Info.CPU = ANY_CPU then
1989 Result := 0;
1990
1991 Proc := 0;
1992 while Proc < Last_Proc loop
1993 Result := p_online (Proc, PR_STATUS);
1994 exit when Result = PR_ONLINE;
1995 Proc := Proc + 1;
1996 end loop;
1997
1998 Result :=
1999 processor_bind
2000 (P_LWPID, id_t (T.Common.LL.LWP), Proc, null);
2001 pragma Assert (Result = 0);
2002
2003 else
2004 -- Use specified processor
2005
2006 if T.Common.Task_Info.CPU < 0
2007 or else T.Common.Task_Info.CPU > Last_Proc
2008 then
2009 raise Invalid_CPU_Number;
2010 end if;
2011
2012 Result :=
2013 processor_bind
2014 (P_LWPID, id_t (T.Common.LL.LWP),
2015 T.Common.Task_Info.CPU, null);
2016 pragma Assert (Result = 0);
2017 end if;
2018 end if;
2019
2020 -- Handle dispatching domains
2021
2022 elsif T.Common.Domain /= null
2023 and then (T.Common.Domain /= ST.System_Domain
2024 or else T.Common.Domain.all /=
2025 (Multiprocessors.CPU'First ..
2026 Multiprocessors.Number_Of_CPUs => True))
2027 then
2028 declare
2029 CPU_Set : aliased psetid_t;
2030 Result : int;
2031
2032 begin
2033 Result := pset_create (CPU_Set'Access);
2034 pragma Assert (Result = 0);
2035
2036 -- Set the affinity to all the processors belonging to the
2037 -- dispatching domain.
2038
2039 for Proc in T.Common.Domain'Range loop
2040
2041 -- The Ada CPU numbering starts at 1 while the subprogram to
2042 -- set the affinity starts at 0, therefore we must substract 1.
2043
2044 if T.Common.Domain (Proc) then
2045 Result :=
2046 pset_assign (CPU_Set, processorid_t (Proc) - 1, null);
2047 pragma Assert (Result = 0);
2048 end if;
2049 end loop;
2050
2051 Result :=
2052 pset_bind (CPU_Set, P_LWPID, id_t (T.Common.LL.LWP), null);
2053 pragma Assert (Result = 0);
2054 end;
2055 end if;
2056 end Set_Task_Affinity;
2057
2058 end System.Task_Primitives.Operations;
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