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PR rtl-optimization/79386
[official-gcc.git] / gcc / ada / s-taprop-solaris.adb
bloba508c42e2248ac22d166329bc63e0072461995ca
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) 1992-2014, 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 -- 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 TS : aliased timespec;
789 Result : Interfaces.C.int;
790 begin
791 Result := clock_getres (OSC.CLOCK_REALTIME, TS'Unchecked_Access);
792 pragma Assert (Result = 0);
793
794 return To_Duration (TS);
795 end RT_Resolution;
796
797 -----------
798 -- Yield --
799 -----------
800
801 procedure Yield (Do_Yield : Boolean := True) is
802 begin
803 if Do_Yield then
804 System.OS_Interface.thr_yield;
805 end if;
806 end Yield;
807
808 -----------
809 -- Self ---
810 -----------
811
812 function Self return Task_Id renames Specific.Self;
813
814 ------------------
815 -- Set_Priority --
816 ------------------
817
818 procedure Set_Priority
819 (T : Task_Id;
820 Prio : System.Any_Priority;
821 Loss_Of_Inheritance : Boolean := False)
822 is
823 pragma Unreferenced (Loss_Of_Inheritance);
824
825 Result : Interfaces.C.int;
826 pragma Unreferenced (Result);
827
828 Param : aliased struct_pcparms;
829
830 use Task_Info;
831
832 begin
833 T.Common.Current_Priority := Prio;
834
835 if Priority_Ceiling_Emulation then
836 T.Common.LL.Active_Priority := Prio;
837 end if;
838
839 if Using_Real_Time_Class then
840 Param.pc_cid := Prio_Param.pc_cid;
841 Param.rt_pri := pri_t (Prio);
842 Param.rt_tqsecs := Prio_Param.rt_tqsecs;
843 Param.rt_tqnsecs := Prio_Param.rt_tqnsecs;
844
845 Result := Interfaces.C.int (
846 priocntl (PC_VERSION, P_LWPID, T.Common.LL.LWP, PC_SETPARMS,
847 Param'Address));
848
849 else
850 if T.Common.Task_Info /= null
851 and then not T.Common.Task_Info.Bound_To_LWP
852 then
853 -- The task is not bound to a LWP, so use thr_setprio
854
855 Result :=
856 thr_setprio (T.Common.LL.Thread, Interfaces.C.int (Prio));
857
858 else
859 -- The task is bound to a LWP, use priocntl
860 -- ??? TBD
861
862 null;
863 end if;
864 end if;
865 end Set_Priority;
866
867 ------------------
868 -- Get_Priority --
869 ------------------
870
871 function Get_Priority (T : Task_Id) return System.Any_Priority is
872 begin
873 return T.Common.Current_Priority;
874 end Get_Priority;
875
876 ----------------
877 -- Enter_Task --
878 ----------------
879
880 procedure Enter_Task (Self_ID : Task_Id) is
881 begin
882 Self_ID.Common.LL.Thread := thr_self;
883 Self_ID.Common.LL.LWP := lwp_self;
884
885 Set_Task_Affinity (Self_ID);
886 Specific.Set (Self_ID);
887
888 -- We need the above code even if we do direct fetch of Task_Id in Self
889 -- for the main task on Sun, x86 Solaris and for gcc 2.7.2.
890 end Enter_Task;
891
892 -------------------
893 -- Is_Valid_Task --
894 -------------------
895
896 function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
897
898 -----------------------------
899 -- Register_Foreign_Thread --
900 -----------------------------
901
902 function Register_Foreign_Thread return Task_Id is
903 begin
904 if Is_Valid_Task then
905 return Self;
906 else
907 return Register_Foreign_Thread (thr_self);
908 end if;
909 end Register_Foreign_Thread;
910
911 --------------------
912 -- Initialize_TCB --
913 --------------------
914
915 procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
916 Result : Interfaces.C.int := 0;
917
918 begin
919 -- Give the task a unique serial number
920
921 Self_ID.Serial_Number := Next_Serial_Number;
922 Next_Serial_Number := Next_Serial_Number + 1;
923 pragma Assert (Next_Serial_Number /= 0);
924
925 Self_ID.Common.LL.Thread := Null_Thread_Id;
926
927 if not Single_Lock then
928 Result :=
929 mutex_init
930 (Self_ID.Common.LL.L.L'Access, USYNC_THREAD, System.Null_Address);
931 Self_ID.Common.LL.L.Level :=
932 Private_Task_Serial_Number (Self_ID.Serial_Number);
933 pragma Assert (Result = 0 or else Result = ENOMEM);
934 end if;
935
936 if Result = 0 then
937 Result := cond_init (Self_ID.Common.LL.CV'Access, USYNC_THREAD, 0);
938 pragma Assert (Result = 0 or else Result = ENOMEM);
939 end if;
940
941 if Result = 0 then
942 Succeeded := True;
943 else
944 if not Single_Lock then
945 Result := mutex_destroy (Self_ID.Common.LL.L.L'Access);
946 pragma Assert (Result = 0);
947 end if;
948
949 Succeeded := False;
950 end if;
951 end Initialize_TCB;
952
953 -----------------
954 -- Create_Task --
955 -----------------
956
957 procedure Create_Task
958 (T : Task_Id;
959 Wrapper : System.Address;
960 Stack_Size : System.Parameters.Size_Type;
961 Priority : System.Any_Priority;
962 Succeeded : out Boolean)
963 is
964 pragma Unreferenced (Priority);
965
966 Result : Interfaces.C.int;
967 Adjusted_Stack_Size : Interfaces.C.size_t;
968 Opts : Interfaces.C.int := THR_DETACHED;
969
970 Page_Size : constant System.Parameters.Size_Type := 4096;
971 -- This constant is for reserving extra space at the
972 -- end of the stack, which can be used by the stack
973 -- checking as guard page. The idea is that we need
974 -- to have at least Stack_Size bytes available for
975 -- actual use.
976
977 use System.Task_Info;
978 use type System.Multiprocessors.CPU_Range;
979
980 begin
981 -- Check whether both Dispatching_Domain and CPU are specified for the
982 -- task, and the CPU value is not contained within the range of
983 -- processors for the domain.
984
985 if T.Common.Domain /= null
986 and then T.Common.Base_CPU /= System.Multiprocessors.Not_A_Specific_CPU
987 and then
988 (T.Common.Base_CPU not in T.Common.Domain'Range
989 or else not T.Common.Domain (T.Common.Base_CPU))
990 then
991 Succeeded := False;
992 return;
993 end if;
994
995 Adjusted_Stack_Size := Interfaces.C.size_t (Stack_Size + Page_Size);
996
997 -- Since the initial signal mask of a thread is inherited from the
998 -- creator, and the Environment task has all its signals masked, we
999 -- do not need to manipulate caller's signal mask at this point.
1000 -- All tasks in RTS will have All_Tasks_Mask initially.
1001
1002 if T.Common.Task_Info /= null then
1003 if T.Common.Task_Info.New_LWP then
1004 Opts := Opts + THR_NEW_LWP;
1005 end if;
1006
1007 if T.Common.Task_Info.Bound_To_LWP then
1008 Opts := Opts + THR_BOUND;
1009 end if;
1010
1011 else
1012 Opts := THR_DETACHED + THR_BOUND;
1013 end if;
1014
1015 -- Note: the use of Unrestricted_Access in the following call is needed
1016 -- because otherwise we have an error of getting a access-to-volatile
1017 -- value which points to a non-volatile object. But in this case it is
1018 -- safe to do this, since we know we have no problems with aliasing and
1019 -- Unrestricted_Access bypasses this check.
1020
1021 Result :=
1022 thr_create
1023 (System.Null_Address,
1024 Adjusted_Stack_Size,
1025 Thread_Body_Access (Wrapper),
1026 To_Address (T),
1027 Opts,
1028 T.Common.LL.Thread'Unrestricted_Access);
1029
1030 Succeeded := Result = 0;
1031 pragma Assert
1032 (Result = 0
1033 or else Result = ENOMEM
1034 or else Result = EAGAIN);
1035 end Create_Task;
1036
1037 ------------------
1038 -- Finalize_TCB --
1039 ------------------
1040
1041 procedure Finalize_TCB (T : Task_Id) is
1042 Result : Interfaces.C.int;
1043
1044 begin
1045 T.Common.LL.Thread := Null_Thread_Id;
1046
1047 if not Single_Lock then
1048 Result := mutex_destroy (T.Common.LL.L.L'Access);
1049 pragma Assert (Result = 0);
1050 end if;
1051
1052 Result := cond_destroy (T.Common.LL.CV'Access);
1053 pragma Assert (Result = 0);
1054
1055 if T.Known_Tasks_Index /= -1 then
1056 Known_Tasks (T.Known_Tasks_Index) := null;
1057 end if;
1058
1059 ATCB_Allocation.Free_ATCB (T);
1060 end Finalize_TCB;
1061
1062 ---------------
1063 -- Exit_Task --
1064 ---------------
1065
1066 -- This procedure must be called with abort deferred. It can no longer
1067 -- call Self or access the current task's ATCB, since the ATCB has been
1068 -- deallocated.
1069
1070 procedure Exit_Task is
1071 begin
1072 Specific.Set (null);
1073 end Exit_Task;
1074
1075 ----------------
1076 -- Abort_Task --
1077 ----------------
1078
1079 procedure Abort_Task (T : Task_Id) is
1080 Result : Interfaces.C.int;
1081 begin
1082 if Abort_Handler_Installed then
1083 pragma Assert (T /= Self);
1084 Result :=
1085 thr_kill
1086 (T.Common.LL.Thread,
1087 Signal (System.Interrupt_Management.Abort_Task_Interrupt));
1088 pragma Assert (Result = 0);
1089 end if;
1090 end Abort_Task;
1091
1092 -----------
1093 -- Sleep --
1094 -----------
1095
1096 procedure Sleep
1097 (Self_ID : Task_Id;
1098 Reason : Task_States)
1099 is
1100 Result : Interfaces.C.int;
1101
1102 begin
1103 pragma Assert (Check_Sleep (Reason));
1104
1105 if Single_Lock then
1106 Result :=
1107 cond_wait
1108 (Self_ID.Common.LL.CV'Access, Single_RTS_Lock.L'Access);
1109 else
1110 Result :=
1111 cond_wait
1112 (Self_ID.Common.LL.CV'Access, Self_ID.Common.LL.L.L'Access);
1113 end if;
1114
1115 pragma Assert
1116 (Record_Wakeup (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Reason));
1117 pragma Assert (Result = 0 or else Result = EINTR);
1118 end Sleep;
1119
1120 -- Note that we are relying heavily here on GNAT representing
1121 -- Calendar.Time, System.Real_Time.Time, Duration,
1122 -- System.Real_Time.Time_Span in the same way, i.e., as a 64-bit count of
1123 -- nanoseconds.
1124
1125 -- This allows us to always pass the timeout value as a Duration
1126
1127 -- ???
1128 -- We are taking liberties here with the semantics of the delays. That is,
1129 -- we make no distinction between delays on the Calendar clock and delays
1130 -- on the Real_Time clock. That is technically incorrect, if the Calendar
1131 -- clock happens to be reset or adjusted. To solve this defect will require
1132 -- modification to the compiler interface, so that it can pass through more
1133 -- information, to tell us here which clock to use.
1134
1135 -- cond_timedwait will return if any of the following happens:
1136 -- 1) some other task did cond_signal on this condition variable
1137 -- In this case, the return value is 0
1138 -- 2) the call just returned, for no good reason
1139 -- This is called a "spurious wakeup".
1140 -- In this case, the return value may also be 0.
1141 -- 3) the time delay expires
1142 -- In this case, the return value is ETIME
1143 -- 4) this task received a signal, which was handled by some
1144 -- handler procedure, and now the thread is resuming execution
1145 -- UNIX calls this an "interrupted" system call.
1146 -- In this case, the return value is EINTR
1147
1148 -- If the cond_timedwait returns 0 or EINTR, it is still possible that the
1149 -- time has actually expired, and by chance a signal or cond_signal
1150 -- occurred at around the same time.
1151
1152 -- We have also observed that on some OS's the value ETIME will be
1153 -- returned, but the clock will show that the full delay has not yet
1154 -- expired.
1155
1156 -- For these reasons, we need to check the clock after return from
1157 -- cond_timedwait. If the time has expired, we will set Timedout = True.
1158
1159 -- This check might be omitted for systems on which the cond_timedwait()
1160 -- never returns early or wakes up spuriously.
1161
1162 -- Annex D requires that completion of a delay cause the task to go to the
1163 -- end of its priority queue, regardless of whether the task actually was
1164 -- suspended by the delay. Since cond_timedwait does not do this on
1165 -- Solaris, we add a call to thr_yield at the end. We might do this at the
1166 -- beginning, instead, but then the round-robin effect would not be the
1167 -- same; the delayed task would be ahead of other tasks of the same
1168 -- priority that awoke while it was sleeping.
1169
1170 -- For Timed_Sleep, we are expecting possible cond_signals to indicate
1171 -- other events (e.g., completion of a RV or completion of the abortable
1172 -- part of an async. select), we want to always return if interrupted. The
1173 -- caller will be responsible for checking the task state to see whether
1174 -- the wakeup was spurious, and to go back to sleep again in that case. We
1175 -- don't need to check for pending abort or priority change on the way in
1176 -- our out; that is the caller's responsibility.
1177
1178 -- For Timed_Delay, we are not expecting any cond_signals or other
1179 -- interruptions, except for priority changes and aborts. Therefore, we
1180 -- don't want to return unless the delay has actually expired, or the call
1181 -- has been aborted. In this case, since we want to implement the entire
1182 -- delay statement semantics, we do need to check for pending abort and
1183 -- priority changes. We can quietly handle priority changes inside the
1184 -- procedure, since there is no entry-queue reordering involved.
1185
1186 -----------------
1187 -- Timed_Sleep --
1188 -----------------
1189
1190 procedure Timed_Sleep
1191 (Self_ID : Task_Id;
1192 Time : Duration;
1193 Mode : ST.Delay_Modes;
1194 Reason : System.Tasking.Task_States;
1195 Timedout : out Boolean;
1196 Yielded : out Boolean)
1197 is
1198 Base_Time : constant Duration := Monotonic_Clock;
1199 Check_Time : Duration := Base_Time;
1200 Abs_Time : Duration;
1201 Request : aliased timespec;
1202 Result : Interfaces.C.int;
1203
1204 begin
1205 pragma Assert (Check_Sleep (Reason));
1206 Timedout := True;
1207 Yielded := False;
1208
1209 Abs_Time :=
1210 (if Mode = Relative
1211 then Duration'Min (Time, Max_Sensible_Delay) + Check_Time
1212 else Duration'Min (Check_Time + Max_Sensible_Delay, Time));
1213
1214 if Abs_Time > Check_Time then
1215 Request := To_Timespec (Abs_Time);
1216 loop
1217 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
1218
1219 if Single_Lock then
1220 Result :=
1221 cond_timedwait
1222 (Self_ID.Common.LL.CV'Access,
1223 Single_RTS_Lock.L'Access, Request'Access);
1224 else
1225 Result :=
1226 cond_timedwait
1227 (Self_ID.Common.LL.CV'Access,
1228 Self_ID.Common.LL.L.L'Access, Request'Access);
1229 end if;
1230
1231 Yielded := True;
1232
1233 Check_Time := Monotonic_Clock;
1234 exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
1235
1236 if Result = 0 or Result = EINTR then
1237
1238 -- Somebody may have called Wakeup for us
1239
1240 Timedout := False;
1241 exit;
1242 end if;
1243
1244 pragma Assert (Result = ETIME);
1245 end loop;
1246 end if;
1247
1248 pragma Assert
1249 (Record_Wakeup (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Reason));
1250 end Timed_Sleep;
1251
1252 -----------------
1253 -- Timed_Delay --
1254 -----------------
1255
1256 procedure Timed_Delay
1257 (Self_ID : Task_Id;
1258 Time : Duration;
1259 Mode : ST.Delay_Modes)
1260 is
1261 Base_Time : constant Duration := Monotonic_Clock;
1262 Check_Time : Duration := Base_Time;
1263 Abs_Time : Duration;
1264 Request : aliased timespec;
1265 Result : Interfaces.C.int;
1266 Yielded : Boolean := False;
1267
1268 begin
1269 if Single_Lock then
1270 Lock_RTS;
1271 end if;
1272
1273 Write_Lock (Self_ID);
1274
1275 Abs_Time :=
1276 (if Mode = Relative
1277 then Time + Check_Time
1278 else Duration'Min (Check_Time + Max_Sensible_Delay, Time));
1279
1280 if Abs_Time > Check_Time then
1281 Request := To_Timespec (Abs_Time);
1282 Self_ID.Common.State := Delay_Sleep;
1283
1284 pragma Assert (Check_Sleep (Delay_Sleep));
1285
1286 loop
1287 exit when Self_ID.Pending_ATC_Level < Self_ID.ATC_Nesting_Level;
1288
1289 if Single_Lock then
1290 Result :=
1291 cond_timedwait
1292 (Self_ID.Common.LL.CV'Access,
1293 Single_RTS_Lock.L'Access,
1294 Request'Access);
1295 else
1296 Result :=
1297 cond_timedwait
1298 (Self_ID.Common.LL.CV'Access,
1299 Self_ID.Common.LL.L.L'Access,
1300 Request'Access);
1301 end if;
1302
1303 Yielded := True;
1304
1305 Check_Time := Monotonic_Clock;
1306 exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
1307
1308 pragma Assert
1309 (Result = 0 or else
1310 Result = ETIME or else
1311 Result = EINTR);
1312 end loop;
1313
1314 pragma Assert
1315 (Record_Wakeup
1316 (To_Lock_Ptr (Self_ID.Common.LL.L'Access), Delay_Sleep));
1317
1318 Self_ID.Common.State := Runnable;
1319 end if;
1320
1321 Unlock (Self_ID);
1322
1323 if Single_Lock then
1324 Unlock_RTS;
1325 end if;
1326
1327 if not Yielded then
1328 thr_yield;
1329 end if;
1330 end Timed_Delay;
1331
1332 ------------
1333 -- Wakeup --
1334 ------------
1335
1336 procedure Wakeup
1337 (T : Task_Id;
1338 Reason : Task_States)
1339 is
1340 Result : Interfaces.C.int;
1341 begin
1342 pragma Assert (Check_Wakeup (T, Reason));
1343 Result := cond_signal (T.Common.LL.CV'Access);
1344 pragma Assert (Result = 0);
1345 end Wakeup;
1346
1347 ---------------------------
1348 -- Check_Initialize_Lock --
1349 ---------------------------
1350
1351 -- The following code is intended to check some of the invariant assertions
1352 -- related to lock usage, on which we depend.
1353
1354 function Check_Initialize_Lock
1355 (L : Lock_Ptr;
1356 Level : Lock_Level) return Boolean
1357 is
1358 Self_ID : constant Task_Id := Self;
1359
1360 begin
1361 -- Check that caller is abort-deferred
1362
1363 if Self_ID.Deferral_Level = 0 then
1364 return False;
1365 end if;
1366
1367 -- Check that the lock is not yet initialized
1368
1369 if L.Level /= 0 then
1370 return False;
1371 end if;
1372
1373 L.Level := Lock_Level'Pos (Level) + 1;
1374 return True;
1375 end Check_Initialize_Lock;
1376
1377 ----------------
1378 -- Check_Lock --
1379 ----------------
1380
1381 function Check_Lock (L : Lock_Ptr) return Boolean is
1382 Self_ID : constant Task_Id := Self;
1383 P : Lock_Ptr;
1384
1385 begin
1386 -- Check that the argument is not null
1387
1388 if L = null then
1389 return False;
1390 end if;
1391
1392 -- Check that L is not frozen
1393
1394 if L.Frozen then
1395 return False;
1396 end if;
1397
1398 -- Check that caller is abort-deferred
1399
1400 if Self_ID.Deferral_Level = 0 then
1401 return False;
1402 end if;
1403
1404 -- Check that caller is not holding this lock already
1405
1406 if L.Owner = To_Owner_ID (To_Address (Self_ID)) then
1407 return False;
1408 end if;
1409
1410 if Single_Lock then
1411 return True;
1412 end if;
1413
1414 -- Check that TCB lock order rules are satisfied
1415
1416 P := Self_ID.Common.LL.Locks;
1417 if P /= null then
1418 if P.Level >= L.Level
1419 and then (P.Level > 2 or else L.Level > 2)
1420 then
1421 return False;
1422 end if;
1423 end if;
1424
1425 return True;
1426 end Check_Lock;
1427
1428 -----------------
1429 -- Record_Lock --
1430 -----------------
1431
1432 function Record_Lock (L : Lock_Ptr) return Boolean is
1433 Self_ID : constant Task_Id := Self;
1434 P : Lock_Ptr;
1435
1436 begin
1437 Lock_Count := Lock_Count + 1;
1438
1439 -- There should be no owner for this lock at this point
1440
1441 if L.Owner /= null then
1442 return False;
1443 end if;
1444
1445 -- Record new owner
1446
1447 L.Owner := To_Owner_ID (To_Address (Self_ID));
1448
1449 if Single_Lock then
1450 return True;
1451 end if;
1452
1453 -- Check that TCB lock order rules are satisfied
1454
1455 P := Self_ID.Common.LL.Locks;
1456
1457 if P /= null then
1458 L.Next := P;
1459 end if;
1460
1461 Self_ID.Common.LL.Locking := null;
1462 Self_ID.Common.LL.Locks := L;
1463 return True;
1464 end Record_Lock;
1465
1466 -----------------
1467 -- Check_Sleep --
1468 -----------------
1469
1470 function Check_Sleep (Reason : Task_States) return Boolean is
1471 pragma Unreferenced (Reason);
1472
1473 Self_ID : constant Task_Id := Self;
1474 P : Lock_Ptr;
1475
1476 begin
1477 -- Check that caller is abort-deferred
1478
1479 if Self_ID.Deferral_Level = 0 then
1480 return False;
1481 end if;
1482
1483 if Single_Lock then
1484 return True;
1485 end if;
1486
1487 -- Check that caller is holding own lock, on top of list
1488
1489 if Self_ID.Common.LL.Locks /=
1490 To_Lock_Ptr (Self_ID.Common.LL.L'Access)
1491 then
1492 return False;
1493 end if;
1494
1495 -- Check that TCB lock order rules are satisfied
1496
1497 if Self_ID.Common.LL.Locks.Next /= null then
1498 return False;
1499 end if;
1500
1501 Self_ID.Common.LL.L.Owner := null;
1502 P := Self_ID.Common.LL.Locks;
1503 Self_ID.Common.LL.Locks := Self_ID.Common.LL.Locks.Next;
1504 P.Next := null;
1505 return True;
1506 end Check_Sleep;
1507
1508 -------------------
1509 -- Record_Wakeup --
1510 -------------------
1511
1512 function Record_Wakeup
1513 (L : Lock_Ptr;
1514 Reason : Task_States) return Boolean
1515 is
1516 pragma Unreferenced (Reason);
1517
1518 Self_ID : constant Task_Id := Self;
1519 P : Lock_Ptr;
1520
1521 begin
1522 -- Record new owner
1523
1524 L.Owner := To_Owner_ID (To_Address (Self_ID));
1525
1526 if Single_Lock then
1527 return True;
1528 end if;
1529
1530 -- Check that TCB lock order rules are satisfied
1531
1532 P := Self_ID.Common.LL.Locks;
1533
1534 if P /= null then
1535 L.Next := P;
1536 end if;
1537
1538 Self_ID.Common.LL.Locking := null;
1539 Self_ID.Common.LL.Locks := L;
1540 return True;
1541 end Record_Wakeup;
1542
1543 ------------------
1544 -- Check_Wakeup --
1545 ------------------
1546
1547 function Check_Wakeup
1548 (T : Task_Id;
1549 Reason : Task_States) return Boolean
1550 is
1551 Self_ID : constant Task_Id := Self;
1552
1553 begin
1554 -- Is caller holding T's lock?
1555
1556 if T.Common.LL.L.Owner /= To_Owner_ID (To_Address (Self_ID)) then
1557 return False;
1558 end if;
1559
1560 -- Are reasons for wakeup and sleep consistent?
1561
1562 if T.Common.State /= Reason then
1563 return False;
1564 end if;
1565
1566 return True;
1567 end Check_Wakeup;
1568
1569 ------------------
1570 -- Check_Unlock --
1571 ------------------
1572
1573 function Check_Unlock (L : Lock_Ptr) return Boolean is
1574 Self_ID : constant Task_Id := Self;
1575 P : Lock_Ptr;
1576
1577 begin
1578 Unlock_Count := Unlock_Count + 1;
1579
1580 if L = null then
1581 return False;
1582 end if;
1583
1584 if L.Buddy /= null then
1585 return False;
1586 end if;
1587
1588 -- Magic constant 4???
1589
1590 if L.Level = 4 then
1591 Check_Count := Unlock_Count;
1592 end if;
1593
1594 -- Magic constant 1000???
1595
1596 if Unlock_Count - Check_Count > 1000 then
1597 Check_Count := Unlock_Count;
1598 end if;
1599
1600 -- Check that caller is abort-deferred
1601
1602 if Self_ID.Deferral_Level = 0 then
1603 return False;
1604 end if;
1605
1606 -- Check that caller is holding this lock, on top of list
1607
1608 if Self_ID.Common.LL.Locks /= L then
1609 return False;
1610 end if;
1611
1612 -- Record there is no owner now
1613
1614 L.Owner := null;
1615 P := Self_ID.Common.LL.Locks;
1616 Self_ID.Common.LL.Locks := Self_ID.Common.LL.Locks.Next;
1617 P.Next := null;
1618 return True;
1619 end Check_Unlock;
1620
1621 --------------------
1622 -- Check_Finalize --
1623 --------------------
1624
1625 function Check_Finalize_Lock (L : Lock_Ptr) return Boolean is
1626 Self_ID : constant Task_Id := Self;
1627
1628 begin
1629 -- Check that caller is abort-deferred
1630
1631 if Self_ID.Deferral_Level = 0 then
1632 return False;
1633 end if;
1634
1635 -- Check that no one is holding this lock
1636
1637 if L.Owner /= null then
1638 return False;
1639 end if;
1640
1641 L.Frozen := True;
1642 return True;
1643 end Check_Finalize_Lock;
1644
1645 ----------------
1646 -- Initialize --
1647 ----------------
1648
1649 procedure Initialize (S : in out Suspension_Object) is
1650 Result : Interfaces.C.int;
1651
1652 begin
1653 -- Initialize internal state (always to zero (RM D.10(6)))
1654
1655 S.State := False;
1656 S.Waiting := False;
1657
1658 -- Initialize internal mutex
1659
1660 Result := mutex_init (S.L'Access, USYNC_THREAD, System.Null_Address);
1661 pragma Assert (Result = 0 or else Result = ENOMEM);
1662
1663 if Result = ENOMEM then
1664 raise Storage_Error with "Failed to allocate a lock";
1665 end if;
1666
1667 -- Initialize internal condition variable
1668
1669 Result := cond_init (S.CV'Access, USYNC_THREAD, 0);
1670 pragma Assert (Result = 0 or else Result = ENOMEM);
1671
1672 if Result /= 0 then
1673 Result := mutex_destroy (S.L'Access);
1674 pragma Assert (Result = 0);
1675
1676 if Result = ENOMEM then
1677 raise Storage_Error;
1678 end if;
1679 end if;
1680 end Initialize;
1681
1682 --------------
1683 -- Finalize --
1684 --------------
1685
1686 procedure Finalize (S : in out Suspension_Object) is
1687 Result : Interfaces.C.int;
1688
1689 begin
1690 -- Destroy internal mutex
1691
1692 Result := mutex_destroy (S.L'Access);
1693 pragma Assert (Result = 0);
1694
1695 -- Destroy internal condition variable
1696
1697 Result := cond_destroy (S.CV'Access);
1698 pragma Assert (Result = 0);
1699 end Finalize;
1700
1701 -------------------
1702 -- Current_State --
1703 -------------------
1704
1705 function Current_State (S : Suspension_Object) return Boolean is
1706 begin
1707 -- We do not want to use lock on this read operation. State is marked
1708 -- as Atomic so that we ensure that the value retrieved is correct.
1709
1710 return S.State;
1711 end Current_State;
1712
1713 ---------------
1714 -- Set_False --
1715 ---------------
1716
1717 procedure Set_False (S : in out Suspension_Object) is
1718 Result : Interfaces.C.int;
1719
1720 begin
1721 SSL.Abort_Defer.all;
1722
1723 Result := mutex_lock (S.L'Access);
1724 pragma Assert (Result = 0);
1725
1726 S.State := False;
1727
1728 Result := mutex_unlock (S.L'Access);
1729 pragma Assert (Result = 0);
1730
1731 SSL.Abort_Undefer.all;
1732 end Set_False;
1733
1734 --------------
1735 -- Set_True --
1736 --------------
1737
1738 procedure Set_True (S : in out Suspension_Object) is
1739 Result : Interfaces.C.int;
1740
1741 begin
1742 SSL.Abort_Defer.all;
1743
1744 Result := mutex_lock (S.L'Access);
1745 pragma Assert (Result = 0);
1746
1747 -- If there is already a task waiting on this suspension object then
1748 -- we resume it, leaving the state of the suspension object to False,
1749 -- as it is specified in ARM D.10 par. 9. Otherwise, it just leaves
1750 -- the state to True.
1751
1752 if S.Waiting then
1753 S.Waiting := False;
1754 S.State := False;
1755
1756 Result := cond_signal (S.CV'Access);
1757 pragma Assert (Result = 0);
1758
1759 else
1760 S.State := True;
1761 end if;
1762
1763 Result := mutex_unlock (S.L'Access);
1764 pragma Assert (Result = 0);
1765
1766 SSL.Abort_Undefer.all;
1767 end Set_True;
1768
1769 ------------------------
1770 -- Suspend_Until_True --
1771 ------------------------
1772
1773 procedure Suspend_Until_True (S : in out Suspension_Object) is
1774 Result : Interfaces.C.int;
1775
1776 begin
1777 SSL.Abort_Defer.all;
1778
1779 Result := mutex_lock (S.L'Access);
1780 pragma Assert (Result = 0);
1781
1782 if S.Waiting then
1783
1784 -- Program_Error must be raised upon calling Suspend_Until_True
1785 -- if another task is already waiting on that suspension object
1786 -- (RM D.10(10)).
1787
1788 Result := mutex_unlock (S.L'Access);
1789 pragma Assert (Result = 0);
1790
1791 SSL.Abort_Undefer.all;
1792
1793 raise Program_Error;
1794
1795 else
1796 -- Suspend the task if the state is False. Otherwise, the task
1797 -- continues its execution, and the state of the suspension object
1798 -- is set to False (ARM D.10 par. 9).
1799
1800 if S.State then
1801 S.State := False;
1802 else
1803 S.Waiting := True;
1804
1805 loop
1806 -- Loop in case pthread_cond_wait returns earlier than expected
1807 -- (e.g. in case of EINTR caused by a signal).
1808
1809 Result := cond_wait (S.CV'Access, S.L'Access);
1810 pragma Assert (Result = 0 or else Result = EINTR);
1811
1812 exit when not S.Waiting;
1813 end loop;
1814 end if;
1815
1816 Result := mutex_unlock (S.L'Access);
1817 pragma Assert (Result = 0);
1818
1819 SSL.Abort_Undefer.all;
1820 end if;
1821 end Suspend_Until_True;
1822
1823 ----------------
1824 -- Check_Exit --
1825 ----------------
1826
1827 function Check_Exit (Self_ID : Task_Id) return Boolean is
1828 begin
1829 -- Check that caller is just holding Global_Task_Lock and no other locks
1830
1831 if Self_ID.Common.LL.Locks = null then
1832 return False;
1833 end if;
1834
1835 -- 2 = Global_Task_Level
1836
1837 if Self_ID.Common.LL.Locks.Level /= 2 then
1838 return False;
1839 end if;
1840
1841 if Self_ID.Common.LL.Locks.Next /= null then
1842 return False;
1843 end if;
1844
1845 -- Check that caller is abort-deferred
1846
1847 if Self_ID.Deferral_Level = 0 then
1848 return False;
1849 end if;
1850
1851 return True;
1852 end Check_Exit;
1853
1854 --------------------
1855 -- Check_No_Locks --
1856 --------------------
1857
1858 function Check_No_Locks (Self_ID : Task_Id) return Boolean is
1859 begin
1860 return Self_ID.Common.LL.Locks = null;
1861 end Check_No_Locks;
1862
1863 ----------------------
1864 -- Environment_Task --
1865 ----------------------
1866
1867 function Environment_Task return Task_Id is
1868 begin
1869 return Environment_Task_Id;
1870 end Environment_Task;
1871
1872 --------------
1873 -- Lock_RTS --
1874 --------------
1875
1876 procedure Lock_RTS is
1877 begin
1878 Write_Lock (Single_RTS_Lock'Access, Global_Lock => True);
1879 end Lock_RTS;
1880
1881 ----------------
1882 -- Unlock_RTS --
1883 ----------------
1884
1885 procedure Unlock_RTS is
1886 begin
1887 Unlock (Single_RTS_Lock'Access, Global_Lock => True);
1888 end Unlock_RTS;
1889
1890 ------------------
1891 -- Suspend_Task --
1892 ------------------
1893
1894 function Suspend_Task
1895 (T : ST.Task_Id;
1896 Thread_Self : Thread_Id) return Boolean
1897 is
1898 begin
1899 if T.Common.LL.Thread /= Thread_Self then
1900 return thr_suspend (T.Common.LL.Thread) = 0;
1901 else
1902 return True;
1903 end if;
1904 end Suspend_Task;
1905
1906 -----------------
1907 -- Resume_Task --
1908 -----------------
1909
1910 function Resume_Task
1911 (T : ST.Task_Id;
1912 Thread_Self : Thread_Id) return Boolean
1913 is
1914 begin
1915 if T.Common.LL.Thread /= Thread_Self then
1916 return thr_continue (T.Common.LL.Thread) = 0;
1917 else
1918 return True;
1919 end if;
1920 end Resume_Task;
1921
1922 --------------------
1923 -- Stop_All_Tasks --
1924 --------------------
1925
1926 procedure Stop_All_Tasks is
1927 begin
1928 null;
1929 end Stop_All_Tasks;
1930
1931 ---------------
1932 -- Stop_Task --
1933 ---------------
1934
1935 function Stop_Task (T : ST.Task_Id) return Boolean is
1936 pragma Unreferenced (T);
1937 begin
1938 return False;
1939 end Stop_Task;
1940
1941 -------------------
1942 -- Continue_Task --
1943 -------------------
1944
1945 function Continue_Task (T : ST.Task_Id) return Boolean is
1946 pragma Unreferenced (T);
1947 begin
1948 return False;
1949 end Continue_Task;
1950
1951 -----------------------
1952 -- Set_Task_Affinity --
1953 -----------------------
1954
1955 procedure Set_Task_Affinity (T : ST.Task_Id) is
1956 Result : Interfaces.C.int;
1957 Proc : processorid_t; -- User processor #
1958 Last_Proc : processorid_t; -- Last processor #
1959
1960 use System.Task_Info;
1961 use type System.Multiprocessors.CPU_Range;
1962
1963 begin
1964 -- Do nothing if the underlying thread has not yet been created. If the
1965 -- thread has not yet been created then the proper affinity will be set
1966 -- during its creation.
1967
1968 if T.Common.LL.Thread = Null_Thread_Id then
1969 null;
1970
1971 -- pragma CPU
1972
1973 elsif T.Common.Base_CPU /=
1974 System.Multiprocessors.Not_A_Specific_CPU
1975 then
1976 -- The CPU numbering in pragma CPU starts at 1 while the subprogram
1977 -- to set the affinity starts at 0, therefore we must substract 1.
1978
1979 Result :=
1980 processor_bind
1981 (P_LWPID, id_t (T.Common.LL.LWP),
1982 processorid_t (T.Common.Base_CPU) - 1, null);
1983 pragma Assert (Result = 0);
1984
1985 -- Task_Info
1986
1987 elsif T.Common.Task_Info /= null then
1988 if T.Common.Task_Info.New_LWP
1989 and then T.Common.Task_Info.CPU /= CPU_UNCHANGED
1990 then
1991 Last_Proc := Num_Procs - 1;
1992
1993 if T.Common.Task_Info.CPU = ANY_CPU then
1994 Result := 0;
1995
1996 Proc := 0;
1997 while Proc < Last_Proc loop
1998 Result := p_online (Proc, PR_STATUS);
1999 exit when Result = PR_ONLINE;
2000 Proc := Proc + 1;
2001 end loop;
2002
2003 Result :=
2004 processor_bind
2005 (P_LWPID, id_t (T.Common.LL.LWP), Proc, null);
2006 pragma Assert (Result = 0);
2007
2008 else
2009 -- Use specified processor
2010
2011 if T.Common.Task_Info.CPU < 0
2012 or else T.Common.Task_Info.CPU > Last_Proc
2013 then
2014 raise Invalid_CPU_Number;
2015 end if;
2016
2017 Result :=
2018 processor_bind
2019 (P_LWPID, id_t (T.Common.LL.LWP),
2020 T.Common.Task_Info.CPU, null);
2021 pragma Assert (Result = 0);
2022 end if;
2023 end if;
2024
2025 -- Handle dispatching domains
2026
2027 elsif T.Common.Domain /= null
2028 and then (T.Common.Domain /= ST.System_Domain
2029 or else T.Common.Domain.all /=
2030 (Multiprocessors.CPU'First ..
2031 Multiprocessors.Number_Of_CPUs => True))
2032 then
2033 declare
2034 CPU_Set : aliased psetid_t;
2035 Result : int;
2036
2037 begin
2038 Result := pset_create (CPU_Set'Access);
2039 pragma Assert (Result = 0);
2040
2041 -- Set the affinity to all the processors belonging to the
2042 -- dispatching domain.
2043
2044 for Proc in T.Common.Domain'Range loop
2045
2046 -- The Ada CPU numbering starts at 1 while the subprogram to
2047 -- set the affinity starts at 0, therefore we must substract 1.
2048
2049 if T.Common.Domain (Proc) then
2050 Result :=
2051 pset_assign (CPU_Set, processorid_t (Proc) - 1, null);
2052 pragma Assert (Result = 0);
2053 end if;
2054 end loop;
2055
2056 Result :=
2057 pset_bind (CPU_Set, P_LWPID, id_t (T.Common.LL.LWP), null);
2058 pragma Assert (Result = 0);
2059 end;
2060 end if;
2061 end Set_Task_Affinity;
2062
2063 end System.Task_Primitives.Operations;
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