1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
|
------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- 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 --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2024, Free Software Foundation, Inc. --
-- --
-- GNARL is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. --
-- Extensive contributions were provided by Ada Core Technologies, Inc. --
-- --
------------------------------------------------------------------------------
-- This is a POSIX-like version of this package
-- This package contains all the GNULL primitives that interface directly with
-- the underlying OS.
-- Note: this file can only be used for POSIX compliant systems that implement
-- SCHED_FIFO and Ceiling Locking correctly.
-- For configurations where SCHED_FIFO and priority ceiling are not a
-- requirement, this file can also be used (e.g AiX threads)
with Ada.Unchecked_Conversion;
with Interfaces.C;
with System.Tasking.Debug;
with System.Interrupt_Management;
with System.OS_Constants;
with System.OS_Primitives;
with System.Task_Info;
with System.Multiprocessors;
with System.Soft_Links;
-- We use System.Soft_Links instead of System.Tasking.Initialization
-- because the later is a higher level package that we shouldn't depend on.
-- For example when using the restricted run time, it is replaced by
-- System.Tasking.Restricted.Stages.
package body System.Task_Primitives.Operations is
package OSC renames System.OS_Constants;
package SSL renames System.Soft_Links;
use System.Tasking.Debug;
use System.Tasking;
use Interfaces.C;
use System.OS_Interface;
use System.Parameters;
use System.OS_Primitives;
----------------
-- Local Data --
----------------
-- The followings are logically constants, but need to be initialized
-- at run time.
Single_RTS_Lock : aliased RTS_Lock;
-- This is a lock to allow only one thread of control in the RTS at
-- a time; it is used to execute in mutual exclusion from all other tasks.
-- Used to protect All_Tasks_List
Environment_Task_Id : Task_Id;
-- A variable to hold Task_Id for the environment task
Locking_Policy : constant Character;
pragma Import (C, Locking_Policy, "__gl_locking_policy");
-- Value of the pragma Locking_Policy:
-- 'C' for Ceiling_Locking
-- 'I' for Inherit_Locking
-- ' ' for none.
Unblocked_Signal_Mask : aliased sigset_t;
-- The set of signals that should unblocked in all tasks
-- The followings are internal configuration constants needed
Next_Serial_Number : Task_Serial_Number := 100;
-- We start at 100, to reserve some special values for
-- using in error checking.
Time_Slice_Val : constant Integer;
pragma Import (C, Time_Slice_Val, "__gl_time_slice_val");
Dispatching_Policy : constant Character;
pragma Import (C, Dispatching_Policy, "__gl_task_dispatching_policy");
Foreign_Task_Elaborated : aliased Boolean := True;
-- Used to identified fake tasks (i.e., non-Ada Threads)
Use_Alternate_Stack : constant Boolean := Alternate_Stack_Size /= 0;
-- Whether to use an alternate signal stack for stack overflows
Abort_Handler_Installed : Boolean := False;
-- True if a handler for the abort signal is installed
function Initialize_Lock
(L : not null access RTS_Lock;
Prio : Any_Priority) return int;
-- Initialize the lock L. If Ceiling_Support is True, then set the ceiling
-- to Prio. Returns 0 for success, or ENOMEM for out-of-memory.
function Get_Policy (Prio : System.Any_Priority) return Character;
pragma Import (C, Get_Policy, "__gnat_get_specific_dispatching");
-- Get priority specific dispatching policy
--------------------
-- Local Packages --
--------------------
package Specific is
procedure Initialize (Environment_Task : Task_Id);
pragma Inline (Initialize);
-- Initialize various data needed by this package
function Is_Valid_Task return Boolean;
pragma Inline (Is_Valid_Task);
-- Does executing thread have a TCB?
procedure Set (Self_Id : Task_Id);
pragma Inline (Set);
-- Set the self id for the current task
function Self return Task_Id;
pragma Inline (Self);
-- Return a pointer to the Ada Task Control Block of the calling task
end Specific;
package body Specific is separate;
-- The body of this package is target specific
package Monotonic is
function Monotonic_Clock return Duration;
pragma Inline (Monotonic_Clock);
-- Returns an absolute time, represented as an offset relative to some
-- unspecified starting point, typically system boot time. This clock
-- is not affected by discontinuous jumps in the system time.
function RT_Resolution return Duration;
pragma Inline (RT_Resolution);
-- Returns resolution of the underlying clock used to implement RT_Clock
procedure Timed_Sleep
(Self_ID : ST.Task_Id;
Time : Duration;
Mode : ST.Delay_Modes;
Reason : System.Tasking.Task_States;
Timedout : out Boolean;
Yielded : out Boolean);
-- Combination of Sleep (above) and Timed_Delay
procedure Timed_Delay
(Self_ID : ST.Task_Id;
Time : Duration;
Mode : ST.Delay_Modes);
-- Implement the semantics of the delay statement.
-- The caller should be abort-deferred and should not hold any locks.
end Monotonic;
package body Monotonic is separate;
----------------------------------
-- ATCB allocation/deallocation --
----------------------------------
package body ATCB_Allocation is separate;
-- The body of this package is shared across several targets
---------------------------------
-- Support for foreign threads --
---------------------------------
function Register_Foreign_Thread
(Thread : Thread_Id;
Sec_Stack_Size : Size_Type := Unspecified_Size) return Task_Id;
-- Allocate and initialize a new ATCB for the current Thread. The size of
-- the secondary stack can be optionally specified.
function Register_Foreign_Thread
(Thread : Thread_Id;
Sec_Stack_Size : Size_Type := Unspecified_Size)
return Task_Id is separate;
-----------------------
-- Local Subprograms --
-----------------------
procedure Abort_Handler (Sig : Signal);
-- Signal handler used to implement asynchronous abort.
-- See also comment before body, below.
function To_Address is
new Ada.Unchecked_Conversion (Task_Id, System.Address);
function GNAT_pthread_condattr_setup
(attr : access pthread_condattr_t) return int;
pragma Import (C,
GNAT_pthread_condattr_setup, "__gnat_pthread_condattr_setup");
-------------------
-- Abort_Handler --
-------------------
-- Target-dependent binding of inter-thread Abort signal to the raising of
-- the Abort_Signal exception.
-- The technical issues and alternatives here are essentially the
-- same as for raising exceptions in response to other signals
-- (e.g. Storage_Error). See code and comments in the package body
-- System.Interrupt_Management.
-- Some implementations may not allow an exception to be propagated out of
-- a handler, and others might leave the signal or interrupt that invoked
-- this handler masked after the exceptional return to the application
-- code.
-- GNAT exceptions are originally implemented using setjmp()/longjmp(). On
-- most UNIX systems, this will allow transfer out of a signal handler,
-- which is usually the only mechanism available for implementing
-- asynchronous handlers of this kind. However, some systems do not
-- restore the signal mask on longjmp(), leaving the abort signal masked.
procedure Abort_Handler (Sig : Signal) is
pragma Unreferenced (Sig);
T : constant Task_Id := Self;
Old_Set : aliased sigset_t;
Result : Interfaces.C.int;
pragma Warnings (Off, Result);
begin
-- It's not safe to raise an exception when using GCC ZCX mechanism.
-- Note that we still need to install a signal handler, since in some
-- cases (e.g. shutdown of the Server_Task in System.Interrupts) we
-- need to send the Abort signal to a task.
if ZCX_By_Default then
return;
end if;
if T.Deferral_Level = 0
and then T.Pending_ATC_Level < T.ATC_Nesting_Level and then
not T.Aborting
then
T.Aborting := True;
-- Make sure signals used for RTS internal purpose are unmasked
Result := pthread_sigmask (SIG_UNBLOCK,
Unblocked_Signal_Mask'Access, Old_Set'Access);
pragma Assert (Result = 0);
raise Standard'Abort_Signal;
end if;
end Abort_Handler;
-----------------
-- Stack_Guard --
-----------------
procedure Stack_Guard (T : ST.Task_Id; On : Boolean) is
Stack_Base : constant Address := Get_Stack_Base (T.Common.LL.Thread);
Page_Size : Address;
Res : Interfaces.C.int;
begin
if Stack_Base_Available then
-- Compute the guard page address
Page_Size := Address (Get_Page_Size);
Res :=
mprotect
(Stack_Base - (Stack_Base mod Page_Size) + Page_Size,
size_t (Page_Size),
prot => (if On then PROT_ON else PROT_OFF));
pragma Assert (Res = 0);
end if;
end Stack_Guard;
--------------------
-- Get_Thread_Id --
--------------------
function Get_Thread_Id (T : ST.Task_Id) return OSI.Thread_Id is
begin
return T.Common.LL.Thread;
end Get_Thread_Id;
----------
-- Self --
----------
function Self return Task_Id renames Specific.Self;
---------------------
-- Initialize_Lock --
---------------------
-- Note: mutexes and cond_variables needed per-task basis are initialized
-- in Initialize_TCB and the Storage_Error is handled. Other mutexes (such
-- as RTS_Lock, Memory_Lock...) used in RTS is initialized before any
-- status change of RTS. Therefore raising Storage_Error in the following
-- routines should be able to be handled safely.
function Initialize_Lock
(L : not null access RTS_Lock;
Prio : Any_Priority) return int
is
Attributes : aliased pthread_mutexattr_t;
Result : int;
Result_2 : aliased int;
begin
Result := pthread_mutexattr_init (Attributes'Access);
pragma Assert (Result = 0 or else Result = ENOMEM);
if Result = ENOMEM then
return Result;
end if;
if Locking_Policy = 'C' then
Result := pthread_mutexattr_setprotocol
(Attributes'Access, PTHREAD_PRIO_PROTECT);
pragma Assert (Result = 0);
Result := pthread_mutexattr_getprotocol
(Attributes'Access, Result_2'Access);
if Result_2 /= PTHREAD_PRIO_PROTECT then
raise Program_Error with "setprotocol failed";
end if;
Result := pthread_mutexattr_setprioceiling
(Attributes'Access, To_Target_Priority (Prio));
pragma Assert (Result = 0);
elsif Locking_Policy = 'I' then
Result := pthread_mutexattr_setprotocol
(Attributes'Access, PTHREAD_PRIO_INHERIT);
pragma Assert (Result = 0);
end if;
Result := pthread_mutex_init (L, Attributes'Access);
pragma Assert (Result = 0 or else Result = ENOMEM);
Result_2 := pthread_mutexattr_destroy (Attributes'Access);
pragma Assert (Result_2 = 0);
return Result;
end Initialize_Lock;
procedure Initialize_Lock
(Prio : System.Any_Priority;
L : not null access Lock)
is
begin
if Initialize_Lock (L.WO'Access, Prio) = ENOMEM then
raise Storage_Error with "Failed to allocate a lock";
end if;
end Initialize_Lock;
procedure Initialize_Lock
(L : not null access RTS_Lock;
Level : Lock_Level)
is
pragma Unreferenced (Level);
begin
if Initialize_Lock (L, Any_Priority'Last) = ENOMEM then
raise Storage_Error with "Failed to allocate a lock";
end if;
end Initialize_Lock;
-------------------
-- Finalize_Lock --
-------------------
procedure Finalize_Lock (L : not null access Lock) is
Result : Interfaces.C.int;
begin
Result := pthread_mutex_destroy (L.WO'Access);
pragma Assert (Result = 0);
end Finalize_Lock;
procedure Finalize_Lock (L : not null access RTS_Lock) is
Result : Interfaces.C.int;
begin
Result := pthread_mutex_destroy (L);
pragma Assert (Result = 0);
end Finalize_Lock;
----------------
-- Write_Lock --
----------------
procedure Write_Lock
(L : not null access Lock; Ceiling_Violation : out Boolean)
is
Self : constant pthread_t := pthread_self;
Result : int;
Policy : aliased int;
Ceiling : aliased int;
Sched : aliased struct_sched_param;
begin
Result := pthread_mutex_lock (L.WO'Access);
-- The cause of EINVAL is a priority ceiling violation
Ceiling_Violation := Result = EINVAL;
pragma Assert (Result = 0 or else Ceiling_Violation);
-- Workaround bug in QNX on ceiling locks: tasks with priority higher
-- than the ceiling priority don't receive EINVAL upon trying to lock.
if Result = 0 and then Locking_Policy = 'C' then
Result := pthread_getschedparam (Self, Policy'Access, Sched'Access);
pragma Assert (Result = 0);
Result := pthread_mutex_getprioceiling (L.WO'Access, Ceiling'Access);
pragma Assert (Result = 0);
-- Ceiling < current priority means Ceiling violation
-- (otherwise the current priority == ceiling)
if Ceiling < Sched.sched_curpriority then
Ceiling_Violation := True;
Result := pthread_mutex_unlock (L.WO'Access);
pragma Assert (Result = 0);
end if;
end if;
end Write_Lock;
procedure Write_Lock (L : not null access RTS_Lock) is
Result : Interfaces.C.int;
begin
Result := pthread_mutex_lock (L);
pragma Assert (Result = 0);
end Write_Lock;
procedure Write_Lock (T : Task_Id) is
Result : Interfaces.C.int;
begin
Result := pthread_mutex_lock (T.Common.LL.L'Access);
pragma Assert (Result = 0);
end Write_Lock;
---------------
-- Read_Lock --
---------------
procedure Read_Lock
(L : not null access Lock; Ceiling_Violation : out Boolean) is
begin
Write_Lock (L, Ceiling_Violation);
end Read_Lock;
------------
-- Unlock --
------------
procedure Unlock (L : not null access Lock) is
Result : Interfaces.C.int;
begin
Result := pthread_mutex_unlock (L.WO'Access);
pragma Assert (Result = 0);
end Unlock;
procedure Unlock (L : not null access RTS_Lock) is
Result : Interfaces.C.int;
begin
Result := pthread_mutex_unlock (L);
pragma Assert (Result = 0);
end Unlock;
procedure Unlock (T : Task_Id) is
Result : Interfaces.C.int;
begin
Result := pthread_mutex_unlock (T.Common.LL.L'Access);
pragma Assert (Result = 0);
end Unlock;
-----------------
-- Set_Ceiling --
-----------------
procedure Set_Ceiling
(L : not null access Lock;
Prio : System.Any_Priority)
is
Result : Interfaces.C.int;
begin
Result := pthread_mutex_setprioceiling
(L.WO'Access, To_Target_Priority (Prio), null);
pragma Assert (Result = 0);
end Set_Ceiling;
-----------
-- Sleep --
-----------
procedure Sleep
(Self_ID : Task_Id;
Reason : System.Tasking.Task_States)
is
pragma Unreferenced (Reason);
Result : Interfaces.C.int;
begin
Result :=
pthread_cond_wait
(cond => Self_ID.Common.LL.CV'Access,
mutex => Self_ID.Common.LL.L'Access);
-- EINTR is not considered a failure
pragma Assert (Result = 0 or else Result = EINTR);
end Sleep;
-----------------
-- Timed_Sleep --
-----------------
-- This is for use within the run-time system, so abort is
-- assumed to be already deferred, and the caller should be
-- holding its own ATCB lock.
procedure Timed_Sleep
(Self_ID : Task_Id;
Time : Duration;
Mode : ST.Delay_Modes;
Reason : Task_States;
Timedout : out Boolean;
Yielded : out Boolean) renames Monotonic.Timed_Sleep;
-----------------
-- Timed_Delay --
-----------------
-- This is for use in implementing delay statements, so we assume the
-- caller is abort-deferred but is holding no locks.
procedure Timed_Delay
(Self_ID : Task_Id;
Time : Duration;
Mode : ST.Delay_Modes) renames Monotonic.Timed_Delay;
---------------------
-- Monotonic_Clock --
---------------------
function Monotonic_Clock return Duration renames Monotonic.Monotonic_Clock;
-------------------
-- RT_Resolution --
-------------------
function RT_Resolution return Duration renames Monotonic.RT_Resolution;
------------
-- Wakeup --
------------
procedure Wakeup (T : Task_Id; Reason : System.Tasking.Task_States) is
pragma Unreferenced (Reason);
Result : Interfaces.C.int;
begin
Result := pthread_cond_signal (T.Common.LL.CV'Access);
pragma Assert (Result = 0);
end Wakeup;
-----------
-- Yield --
-----------
procedure Yield (Do_Yield : Boolean := True) is
Result : Interfaces.C.int;
pragma Unreferenced (Result);
begin
if Do_Yield then
Result := sched_yield;
end if;
end Yield;
------------------
-- Set_Priority --
------------------
procedure Set_Priority
(T : Task_Id;
Prio : System.Any_Priority;
Loss_Of_Inheritance : Boolean := False)
is
pragma Unreferenced (Loss_Of_Inheritance);
Result : Interfaces.C.int;
Old : constant System.Any_Priority := T.Common.Current_Priority;
begin
T.Common.Current_Priority := Prio;
Result := pthread_setschedprio
(T.Common.LL.Thread, To_Target_Priority (Prio));
pragma Assert (Result = 0);
if T.Common.LL.Thread = pthread_self
and then Old > Prio
then
-- When lowering the priority via a pthread_setschedprio, QNX ensures
-- that the running thread remains in the head of the FIFO for tne
-- new priority. Annex D expects the thread to be requeued so let's
-- yield to the other threads of the same priority.
Result := sched_yield;
pragma Assert (Result = 0);
end if;
end Set_Priority;
------------------
-- Get_Priority --
------------------
function Get_Priority (T : Task_Id) return System.Any_Priority is
begin
return T.Common.Current_Priority;
end Get_Priority;
----------------
-- Enter_Task --
----------------
procedure Enter_Task (Self_ID : Task_Id) is
begin
Self_ID.Common.LL.Thread := pthread_self;
Self_ID.Common.LL.LWP := lwp_self;
Specific.Set (Self_ID);
if Use_Alternate_Stack then
declare
Stack : aliased stack_t;
Result : Interfaces.C.int;
begin
Stack.ss_sp := Self_ID.Common.Task_Alternate_Stack;
Stack.ss_size := Alternate_Stack_Size;
Stack.ss_flags := 0;
Result := sigaltstack (Stack'Access, null);
pragma Assert (Result = 0);
end;
end if;
end Enter_Task;
-------------------
-- Is_Valid_Task --
-------------------
function Is_Valid_Task return Boolean renames Specific.Is_Valid_Task;
-----------------------------
-- Register_Foreign_Thread --
-----------------------------
function Register_Foreign_Thread return Task_Id is
begin
if Is_Valid_Task then
return Self;
else
return Register_Foreign_Thread (pthread_self);
end if;
end Register_Foreign_Thread;
--------------------
-- Initialize_TCB --
--------------------
procedure Initialize_TCB (Self_ID : Task_Id; Succeeded : out Boolean) is
Result : Interfaces.C.int;
Cond_Attr : aliased pthread_condattr_t;
begin
-- Give the task a unique serial number
Self_ID.Serial_Number := Next_Serial_Number;
Next_Serial_Number := Next_Serial_Number + 1;
pragma Assert (Next_Serial_Number /= 0);
Result :=
Initialize_Lock (Self_ID.Common.LL.L'Access, Any_Priority'Last);
pragma Assert (Result = 0);
if Result /= 0 then
Succeeded := False;
return;
end if;
Result := pthread_condattr_init (Cond_Attr'Access);
pragma Assert (Result = 0 or else Result = ENOMEM);
if Result = 0 then
Result := GNAT_pthread_condattr_setup (Cond_Attr'Access);
pragma Assert (Result = 0);
Result :=
pthread_cond_init
(Self_ID.Common.LL.CV'Access, Cond_Attr'Access);
pragma Assert (Result = 0 or else Result = ENOMEM);
end if;
if Result = 0 then
Succeeded := True;
else
Result := pthread_mutex_destroy (Self_ID.Common.LL.L'Access);
pragma Assert (Result = 0);
Succeeded := False;
end if;
Result := pthread_condattr_destroy (Cond_Attr'Access);
pragma Assert (Result = 0);
end Initialize_TCB;
-----------------
-- Create_Task --
-----------------
procedure Create_Task
(T : Task_Id;
Wrapper : System.Address;
Stack_Size : System.Parameters.Size_Type;
Priority : System.Any_Priority;
Succeeded : out Boolean)
is
Attributes : aliased pthread_attr_t;
Adjusted_Stack_Size : Interfaces.C.size_t;
Page_Size : constant Interfaces.C.size_t :=
Interfaces.C.size_t (Get_Page_Size);
Sched_Param : aliased struct_sched_param;
Result : Interfaces.C.int;
Priority_Specific_Policy : constant Character := Get_Policy (Priority);
-- Upper case first character of the policy name corresponding to the
-- task as set by a Priority_Specific_Dispatching pragma.
function Thread_Body_Access is new
Ada.Unchecked_Conversion (System.Address, Thread_Body);
begin
Adjusted_Stack_Size :=
Interfaces.C.size_t (Stack_Size + Alternate_Stack_Size);
if Stack_Base_Available then
-- If Stack Checking is supported then allocate 2 additional pages:
-- In the worst case, stack is allocated at something like
-- N * Get_Page_Size - epsilon, we need to add the size for 2 pages
-- to be sure the effective stack size is greater than what
-- has been asked.
Adjusted_Stack_Size := Adjusted_Stack_Size + 2 * Page_Size;
end if;
-- Round stack size as this is required by some OSes (Darwin)
Adjusted_Stack_Size := Adjusted_Stack_Size + Page_Size - 1;
Adjusted_Stack_Size :=
Adjusted_Stack_Size - Adjusted_Stack_Size mod Page_Size;
Result := pthread_attr_init (Attributes'Access);
pragma Assert (Result = 0 or else Result = ENOMEM);
if Result /= 0 then
Succeeded := False;
return;
end if;
Result :=
pthread_attr_setdetachstate
(Attributes'Access, PTHREAD_CREATE_DETACHED);
pragma Assert (Result = 0);
Result :=
pthread_attr_setstacksize
(Attributes'Access, Adjusted_Stack_Size);
pragma Assert (Result = 0);
-- Set thread priority
T.Common.Current_Priority := Priority;
Sched_Param.sched_priority := To_Target_Priority (Priority);
Result := pthread_attr_setinheritsched
(Attributes'Access, PTHREAD_EXPLICIT_SCHED);
pragma Assert (Result = 0);
Result := pthread_attr_setschedparam
(Attributes'Access, Sched_Param'Access);
pragma Assert (Result = 0);
if Time_Slice_Supported
and then (Dispatching_Policy = 'R'
or else Priority_Specific_Policy = 'R'
or else Time_Slice_Val > 0)
then
Result := pthread_attr_setschedpolicy
(Attributes'Access, SCHED_RR);
elsif Dispatching_Policy = 'F'
or else Priority_Specific_Policy = 'F'
or else Time_Slice_Val = 0
then
Result := pthread_attr_setschedpolicy
(Attributes'Access, SCHED_FIFO);
else
Result := pthread_attr_setschedpolicy
(Attributes'Access, SCHED_OTHER);
end if;
pragma Assert (Result = 0);
-- Since the initial signal mask of a thread is inherited from the
-- creator, and the Environment task has all its signals masked, we
-- do not need to manipulate caller's signal mask at this point.
-- All tasks in RTS will have All_Tasks_Mask initially.
-- Note: the use of Unrestricted_Access in the following call is needed
-- because otherwise we have an error of getting a access-to-volatile
-- value which points to a non-volatile object. But in this case it is
-- safe to do this, since we know we have no problems with aliasing and
-- Unrestricted_Access bypasses this check.
Result := pthread_create
(T.Common.LL.Thread'Unrestricted_Access,
Attributes'Access,
Thread_Body_Access (Wrapper),
To_Address (T));
pragma Assert (Result = 0 or else Result = EAGAIN);
Succeeded := Result = 0;
Result := pthread_attr_destroy (Attributes'Access);
pragma Assert (Result = 0);
end Create_Task;
------------------
-- Finalize_TCB --
------------------
procedure Finalize_TCB (T : Task_Id) is
Result : Interfaces.C.int;
begin
Result := pthread_mutex_destroy (T.Common.LL.L'Access);
pragma Assert (Result = 0);
Result := pthread_cond_destroy (T.Common.LL.CV'Access);
pragma Assert (Result = 0);
if T.Known_Tasks_Index /= -1 then
Known_Tasks (T.Known_Tasks_Index) := null;
end if;
ATCB_Allocation.Free_ATCB (T);
end Finalize_TCB;
---------------
-- Exit_Task --
---------------
procedure Exit_Task is
begin
-- Mark this task as unknown, so that if Self is called, it won't
-- return a dangling pointer.
Specific.Set (null);
end Exit_Task;
----------------
-- Abort_Task --
----------------
procedure Abort_Task (T : Task_Id) is
Result : Interfaces.C.int;
begin
if Abort_Handler_Installed then
Result :=
pthread_kill
(T.Common.LL.Thread,
Signal (System.Interrupt_Management.Abort_Task_Interrupt));
pragma Assert (Result = 0);
end if;
end Abort_Task;
----------------
-- Initialize --
----------------
procedure Initialize (S : in out Suspension_Object) is
Mutex_Attr : aliased pthread_mutexattr_t;
Cond_Attr : aliased pthread_condattr_t;
Result : Interfaces.C.int;
begin
-- Initialize internal state (always to False (RM D.10 (6)))
S.State := False;
S.Waiting := False;
-- Initialize internal mutex
Result := pthread_mutexattr_init (Mutex_Attr'Access);
pragma Assert (Result = 0 or else Result = ENOMEM);
if Result = ENOMEM then
raise Storage_Error;
end if;
Result := pthread_mutex_init (S.L'Access, Mutex_Attr'Access);
pragma Assert (Result = 0 or else Result = ENOMEM);
if Result = ENOMEM then
Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
pragma Assert (Result = 0);
raise Storage_Error;
end if;
Result := pthread_mutexattr_destroy (Mutex_Attr'Access);
pragma Assert (Result = 0);
-- Initialize internal condition variable
Result := pthread_condattr_init (Cond_Attr'Access);
pragma Assert (Result = 0 or else Result = ENOMEM);
if Result /= 0 then
Result := pthread_mutex_destroy (S.L'Access);
pragma Assert (Result = 0);
-- Storage_Error is propagated as intended if the allocation of the
-- underlying OS entities fails.
raise Storage_Error;
else
Result := GNAT_pthread_condattr_setup (Cond_Attr'Access);
pragma Assert (Result = 0);
end if;
Result := pthread_cond_init (S.CV'Access, Cond_Attr'Access);
pragma Assert (Result = 0 or else Result = ENOMEM);
if Result /= 0 then
Result := pthread_mutex_destroy (S.L'Access);
pragma Assert (Result = 0);
Result := pthread_condattr_destroy (Cond_Attr'Access);
pragma Assert (Result = 0);
-- Storage_Error is propagated as intended if the allocation of the
-- underlying OS entities fails.
raise Storage_Error;
end if;
Result := pthread_condattr_destroy (Cond_Attr'Access);
pragma Assert (Result = 0);
end Initialize;
--------------
-- Finalize --
--------------
procedure Finalize (S : in out Suspension_Object) is
Result : Interfaces.C.int;
begin
-- Destroy internal mutex
Result := pthread_mutex_destroy (S.L'Access);
pragma Assert (Result = 0);
-- Destroy internal condition variable
Result := pthread_cond_destroy (S.CV'Access);
pragma Assert (Result = 0);
end Finalize;
-------------------
-- Current_State --
-------------------
function Current_State (S : Suspension_Object) return Boolean is
begin
-- We do not want to use lock on this read operation. State is marked
-- as Atomic so that we ensure that the value retrieved is correct.
return S.State;
end Current_State;
---------------
-- Set_False --
---------------
procedure Set_False (S : in out Suspension_Object) is
Result : Interfaces.C.int;
begin
SSL.Abort_Defer.all;
Result := pthread_mutex_lock (S.L'Access);
pragma Assert (Result = 0);
S.State := False;
Result := pthread_mutex_unlock (S.L'Access);
pragma Assert (Result = 0);
SSL.Abort_Undefer.all;
end Set_False;
--------------
-- Set_True --
--------------
procedure Set_True (S : in out Suspension_Object) is
Result : Interfaces.C.int;
begin
SSL.Abort_Defer.all;
Result := pthread_mutex_lock (S.L'Access);
pragma Assert (Result = 0);
-- If there is already a task waiting on this suspension object then
-- we resume it, leaving the state of the suspension object to False,
-- as it is specified in (RM D.10(9)). Otherwise, it just leaves
-- the state to True.
if S.Waiting then
S.Waiting := False;
S.State := False;
Result := pthread_cond_signal (S.CV'Access);
pragma Assert (Result = 0);
else
S.State := True;
end if;
Result := pthread_mutex_unlock (S.L'Access);
pragma Assert (Result = 0);
SSL.Abort_Undefer.all;
end Set_True;
------------------------
-- Suspend_Until_True --
------------------------
procedure Suspend_Until_True (S : in out Suspension_Object) is
Result : Interfaces.C.int;
begin
SSL.Abort_Defer.all;
Result := pthread_mutex_lock (S.L'Access);
pragma Assert (Result = 0);
if S.Waiting then
-- Program_Error must be raised upon calling Suspend_Until_True
-- if another task is already waiting on that suspension object
-- (RM D.10(10)).
Result := pthread_mutex_unlock (S.L'Access);
pragma Assert (Result = 0);
SSL.Abort_Undefer.all;
raise Program_Error;
else
-- Suspend the task if the state is False. Otherwise, the task
-- continues its execution, and the state of the suspension object
-- is set to False (ARM D.10 par. 9).
if S.State then
S.State := False;
else
S.Waiting := True;
loop
-- Loop in case pthread_cond_wait returns earlier than expected
-- (e.g. in case of EINTR caused by a signal).
Result := pthread_cond_wait (S.CV'Access, S.L'Access);
pragma Assert (Result = 0 or else Result = EINTR);
exit when not S.Waiting;
end loop;
end if;
Result := pthread_mutex_unlock (S.L'Access);
pragma Assert (Result = 0);
SSL.Abort_Undefer.all;
end if;
end Suspend_Until_True;
----------------
-- Check_Exit --
----------------
-- Dummy version
function Check_Exit (Self_ID : ST.Task_Id) return Boolean is
pragma Unreferenced (Self_ID);
begin
return True;
end Check_Exit;
--------------------
-- Check_No_Locks --
--------------------
function Check_No_Locks (Self_ID : ST.Task_Id) return Boolean is
pragma Unreferenced (Self_ID);
begin
return True;
end Check_No_Locks;
----------------------
-- Environment_Task --
----------------------
function Environment_Task return Task_Id is
begin
return Environment_Task_Id;
end Environment_Task;
--------------
-- Lock_RTS --
--------------
procedure Lock_RTS is
begin
Write_Lock (Single_RTS_Lock'Access);
end Lock_RTS;
----------------
-- Unlock_RTS --
----------------
procedure Unlock_RTS is
begin
Unlock (Single_RTS_Lock'Access);
end Unlock_RTS;
------------------
-- Suspend_Task --
------------------
function Suspend_Task
(T : ST.Task_Id;
Thread_Self : Thread_Id) return Boolean
is
pragma Unreferenced (T, Thread_Self);
begin
return False;
end Suspend_Task;
-----------------
-- Resume_Task --
-----------------
function Resume_Task
(T : ST.Task_Id;
Thread_Self : Thread_Id) return Boolean
is
pragma Unreferenced (T, Thread_Self);
begin
return False;
end Resume_Task;
--------------------
-- Stop_All_Tasks --
--------------------
procedure Stop_All_Tasks is
begin
null;
end Stop_All_Tasks;
---------------
-- Stop_Task --
---------------
function Stop_Task (T : ST.Task_Id) return Boolean is
pragma Unreferenced (T);
begin
return False;
end Stop_Task;
-------------------
-- Continue_Task --
-------------------
function Continue_Task (T : ST.Task_Id) return Boolean is
pragma Unreferenced (T);
begin
return False;
end Continue_Task;
----------------
-- Initialize --
----------------
procedure Initialize (Environment_Task : Task_Id) is
act : aliased struct_sigaction;
old_act : aliased struct_sigaction;
Tmp_Set : aliased sigset_t;
Result : Interfaces.C.int;
function State
(Int : System.Interrupt_Management.Interrupt_ID) return Character;
pragma Import (C, State, "__gnat_get_interrupt_state");
-- Get interrupt state. Defined in a-init.c
-- The input argument is the interrupt number,
-- and the result is one of the following:
Default : constant Character := 's';
-- 'n' this interrupt not set by any Interrupt_State pragma
-- 'u' Interrupt_State pragma set state to User
-- 'r' Interrupt_State pragma set state to Runtime
-- 's' Interrupt_State pragma set state to System (use "default"
-- system handler)
begin
Environment_Task_Id := Environment_Task;
Interrupt_Management.Initialize;
-- Prepare the set of signals that should unblocked in all tasks
Result := sigemptyset (Unblocked_Signal_Mask'Access);
pragma Assert (Result = 0);
for J in Interrupt_Management.Interrupt_ID loop
if System.Interrupt_Management.Keep_Unmasked (J) then
Result := sigaddset (Unblocked_Signal_Mask'Access, Signal (J));
pragma Assert (Result = 0);
end if;
end loop;
-- Initialize the lock used to synchronize chain of all ATCBs
Initialize_Lock (Single_RTS_Lock'Access, RTS_Lock_Level);
Specific.Initialize (Environment_Task);
if Use_Alternate_Stack then
Environment_Task.Common.Task_Alternate_Stack :=
Alternate_Stack'Address;
end if;
-- Make environment task known here because it doesn't go through
-- Activate_Tasks, which does it for all other tasks.
Known_Tasks (Known_Tasks'First) := Environment_Task;
Environment_Task.Known_Tasks_Index := Known_Tasks'First;
Enter_Task (Environment_Task);
if State
(System.Interrupt_Management.Abort_Task_Interrupt) /= Default
then
act.sa_flags := 0;
act.sa_handler := Abort_Handler'Address;
Result := sigemptyset (Tmp_Set'Access);
pragma Assert (Result = 0);
act.sa_mask := Tmp_Set;
Result :=
sigaction
(Signal (System.Interrupt_Management.Abort_Task_Interrupt),
act'Unchecked_Access,
old_act'Unchecked_Access);
pragma Assert (Result = 0);
Abort_Handler_Installed := True;
end if;
end Initialize;
-----------------------
-- Set_Task_Affinity --
-----------------------
procedure Set_Task_Affinity (T : ST.Task_Id) is
use type Multiprocessors.CPU_Range;
function Thread_Ctl_Ext
(Pid : pid_t;
Tid : Thread_Id;
Command : Interfaces.C.unsigned;
Runmask : Interfaces.C.size_t) return Interfaces.C.int
with
Import, Convention => C, External_Name => "ThreadCtlExt";
-- Thread_Ctl_Ext is a generic thread control function in QNX.
-- It is defined locally because in the C API its second
-- argument is a void pointer that takes different actual
-- pointer types or values depending on the command. This
-- particular instance of this function only accepts the
-- NTO_TCTL_RUNMASK command. The void * pointer in the C
-- interface is interpreted as bitmask for this command.
-- In the binding size_t is used as an integer type that
-- always has the same size as a pointer.
NTO_TCTL_RUNMASK : constant := 4;
-- Command for Thread_Ctl. Using this command in Thread_Ctl
-- allows the caller to pass a bitmask that describes on
-- which CPU the current thread is allowed to run on.
Pid : constant pid_t := getpid;
Result : Interfaces.C.int;
Runmask : Interfaces.C.size_t;
-- Each set bit in runmask represents a processor that the thread
-- can run on. If all bits are set to one the thread can run on any CPU.
begin
if T.Common.Base_CPU = Multiprocessors.Not_A_Specific_CPU then
Runmask := Interfaces.C.size_t'Last;
else
Runmask :=
Interfaces.C.size_t
(2 ** Natural (T.Common.Base_CPU - Multiprocessors.CPU'First));
end if;
Result :=
Thread_Ctl_Ext (Pid, Get_Thread_Id (T), NTO_TCTL_RUNMASK, Runmask);
pragma Assert (Result = 0);
end Set_Task_Affinity;
end System.Task_Primitives.Operations;
|