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