Kernel/threads.c

   1 /*
   2  * Acess2
   3  * threads.c
   4  * - Common Thread Control
   5  */
   6 #include <acess.h>
   7 #include <threads.h>
   8 #include <errno.h>
   9
  10 // === CONSTANTS ===
  11 #define DEFAULT_QUANTUM 10
  12 #define DEFAULT_TICKETS 5
  13 #define MAX_TICKETS             10
  14 const enum eConfigTypes cCONFIG_TYPES[] = {
  15         CFGT_HEAPSTR,   // CFG_VFS_CWD
  16         CFGT_INT,       // CFG_VFS_MAXFILES
  17         CFGT_NULL
  18 };
  19
  20 // === IMPORTS ===
  21 extern void     ArchThreads_Init(void);
  22 extern void     Proc_Start(void);
  23 extern tThread  *Proc_GetCurThread(void);
  24 extern int      Proc_Clone(Uint *Err, Uint Flags);
  25 extern void     Proc_CallFaultHandler(tThread *Thread);
  26
  27 // === PROTOTYPES ===
  28 void    Threads_Init(void);
  29  int    Threads_SetName(char *NewName);
  30 char    *Threads_GetName(int ID);
  31 void    Threads_SetTickets(int Num);
  32 tThread *Threads_CloneTCB(Uint *Err, Uint Flags);
  33  int    Threads_WaitTID(int TID, int *status);
  34 tThread *Threads_GetThread(Uint TID);
  35 void    Threads_AddToDelete(tThread *Thread);
  36 tThread *Threads_int_GetPrev(tThread **List, tThread *Thread);
  37 void    Threads_Exit(int TID, int Status);
  38 void    Threads_Kill(tThread *Thread, int Status);
  39 void    Threads_Yield(void);
  40 void    Threads_Sleep(void);
  41 void    Threads_Wake(tThread *Thread);
  42 void    Threads_AddActive(tThread *Thread);
  43  int    Threads_GetPID(void);
  44  int    Threads_GetTID(void);
  45 tUID    Threads_GetUID(void);
  46  int    Threads_SetUID(Uint *Errno, tUID ID);
  47 tGID    Threads_GetGID(void);
  48  int    Threads_SetGID(Uint *Errno, tUID ID);
  49 void    Threads_Dump(void);
  50
  51 // === GLOBALS ===
  52 // -- Core Thread --
  53 tThread gThreadZero = {
  54         NULL, 0,        // Next, Lock
  55         THREAD_STAT_ACTIVE,     // Status
  56         0,      // Exit Status
  57         0, 0,   // TID, TGID
  58         0, 0,   // UID, GID
  59         0,      // Parent Thread ID
  60         "ThreadZero",   // Name
  61
  62         0,      // Kernel Stack
  63         {0},    // Saved State
  64         {0},    // VM State
  65
  66         0, 0,   // Current Fault, Fault Handler
  67
  68         NULL, NULL,     // Messages, Last Message
  69         DEFAULT_QUANTUM, DEFAULT_QUANTUM,       // Quantum, Remaining
  70         DEFAULT_TICKETS,
  71         {0}     // Default config to zero
  72         };
  73 // -- Processes --
  74 // --- Locks ---
  75 tSpinlock       glThreadListLock = 0;   ///\note NEVER use a heap function while locked
  76 // --- Current State ---
  77 volatile int    giNumActiveThreads = 0;
  78 volatile int    giTotalTickets = 0;
  79 volatile Uint   giNextTID = 1;
  80 // --- Thread Lists ---
  81 tThread *gActiveThreads = NULL;         // Currently Running Threads
  82 tThread *gSleepingThreads = NULL;       // Sleeping Threads
  83 tThread *gDeleteThreads = NULL;         // Threads to delete
  84  int    giNumCPUs = 1;
  85
  86 // === CODE ===
  87 /**
  88  * \fn void Threads_Init(void)
  89  * \brief Initialse the thread list
  90  */
  91 void Threads_Init(void)
  92 {
  93         ArchThreads_Init();
  94
  95         // Create Initial Task
  96         gActiveThreads = &gThreadZero;
  97         giTotalTickets = gThreadZero.NumTickets;
  98         giNumActiveThreads = 1;
  99
 100         #if 1
 101         // Create Idle Task
 102         if(Proc_Clone(0, 0) == 0)
 103         {
 104                 tThread *cur = Proc_GetCurThread();
 105                 cur->ThreadName = "Idle Thread";
 106                 Threads_SetTickets(0);  // Never called randomly
 107                 cur->Quantum = 1;       // 1 slice quantum
 108                 HALT();
 109                 for(;;) {
 110                         HALT(); // Just yeilds
 111                 }
 112         }
 113         #endif
 114
 115         Proc_Start();
 116 }
 117
 118 /**
 119  * \fn void Threads_SetName(char *NewName)
 120  * \brief Sets the current thread's name
 121  */
 122 int Threads_SetName(char *NewName)
 123 {
 124         tThread *cur = Proc_GetCurThread();
 125         if( IsHeap(cur->ThreadName) )
 126                 free( cur->ThreadName );
 127         cur->ThreadName = malloc(strlen(NewName)+1);
 128         strcpy(cur->ThreadName, NewName);
 129         return 0;
 130 }
 131
 132 /**
 133  * \fn char *Threads_GetName(int ID)
 134  * \brief Gets a thread's name
 135  */
 136 char *Threads_GetName(int ID)
 137 {
 138         if(ID == -1) {
 139                 return Proc_GetCurThread()->ThreadName;
 140         }
 141         return NULL;
 142 }
 143
 144 /**
 145  * \fn void Threads_SetTickets(int Num)
 146  * \brief Sets the 'priority' of a task
 147  */
 148 void Threads_SetTickets(int Num)
 149 {
 150         tThread *cur = Proc_GetCurThread();
 151         if(Num < 0)     return;
 152         if(Num > MAX_TICKETS)   Num = MAX_TICKETS;
 153
 154         LOCK( &glThreadListLock );
 155         giTotalTickets -= cur->NumTickets;
 156         cur->NumTickets = Num;
 157         giTotalTickets += Num;
 158         //LOG("giTotalTickets = %i", giTotalTickets);
 159         RELEASE( &glThreadListLock );
 160 }
 161
 162 /**
 163  * \fn tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
 164  */
 165 tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
 166 {
 167         tThread *cur, *new;
 168          int    i;
 169         cur = Proc_GetCurThread();
 170
 171         new = malloc(sizeof(tThread));
 172         if(new == NULL) {
 173                 *Err = -ENOMEM;
 174                 return NULL;
 175         }
 176
 177         new->Next = NULL;
 178         new->IsLocked = 0;
 179         new->Status = THREAD_STAT_ACTIVE;
 180         new->RetStatus = 0;
 181
 182         // Get Thread ID
 183         new->TID = giNextTID++;
 184         new->PTID = cur->TID;
 185
 186         // Clone Name
 187         new->ThreadName = malloc(strlen(cur->ThreadName)+1);
 188         strcpy(new->ThreadName, cur->ThreadName);
 189
 190         // Set Thread Group ID (PID)
 191         if(Flags & CLONE_VM)
 192                 new->TGID = new->TID;
 193         else
 194                 new->TGID = cur->TGID;
 195
 196         // Messages are not inherited
 197         new->Messages = NULL;
 198         new->LastMessage = NULL;
 199
 200         // Set State
 201         new->Remaining = new->Quantum = cur->Quantum;
 202         new->NumTickets = cur->NumTickets;
 203
 204         // Set Signal Handlers
 205         new->CurFaultNum = 0;
 206         new->FaultHandler = cur->FaultHandler;
 207
 208         for( i = 0; i < NUM_CFG_ENTRIES; i ++ )
 209         {
 210                 switch(cCONFIG_TYPES[i])
 211                 {
 212                 default:
 213                         new->Config[i] = cur->Config[i];
 214                         break;
 215                 case CFGT_HEAPSTR:
 216                         if(cur->Config[i])
 217                                 new->Config[i] = (Uint) strdup( (void*)cur->Config[i] );
 218                         else
 219                                 new->Config[i] = 0;
 220                         break;
 221                 }
 222         }
 223
 224         return new;
 225 }
 226
 227 /**
 228  * \fn Uint *Threads_GetCfgPtr(int Id)
 229  */
 230 Uint *Threads_GetCfgPtr(int Id)
 231 {
 232         if(Id < 0 || Id >= NUM_CFG_ENTRIES) {
 233                 Warning("Threads_GetCfgPtr: Index %i is out of bounds", Id);
 234                 return NULL;
 235         }
 236
 237         return &Proc_GetCurThread()->Config[Id];
 238 }
 239
 240 /**
 241  * \fn void Threads_WaitTID(int TID, int *status)
 242  * \brief Wait for a task to change state
 243  */
 244 int Threads_WaitTID(int TID, int *status)
 245 {
 246         // Any Child
 247         if(TID == -1) {
 248
 249                 return -1;
 250         }
 251
 252         // Any peer/child thread
 253         if(TID == 0) {
 254
 255                 return -1;
 256         }
 257
 258         // TGID = abs(TID)
 259         if(TID < -1) {
 260                 return -1;
 261         }
 262
 263         // Specific Thread
 264         if(TID > 0) {
 265                 tThread *t = Threads_GetThread(TID);
 266                  int    initStatus = t->Status;
 267                  int    ret;
 268
 269                 if(initStatus != THREAD_STAT_ZOMBIE) {
 270                         while(t->Status == initStatus) {
 271                                 Threads_Yield();
 272                         }
 273                 }
 274
 275                 ret = t->RetStatus;
 276                 switch(t->Status)
 277                 {
 278                 case THREAD_STAT_ZOMBIE:
 279                         t->Status = THREAD_STAT_DEAD;
 280                         if(status)      *status = 0;
 281                         Threads_AddToDelete( t );
 282                         break;
 283                 default:
 284                         if(status)      *status = -1;
 285                         break;
 286                 }
 287                 return ret;
 288         }
 289
 290         return -1;
 291 }
 292
 293 /**
 294  * \fn tThread *Threads_GetThread(Uint TID)
 295  * \brief Gets a thread given its TID
 296  */
 297 tThread *Threads_GetThread(Uint TID)
 298 {
 299         tThread *thread;
 300
 301         // Search Active List
 302         for(thread = gActiveThreads;
 303                 thread;
 304                 thread = thread->Next)
 305         {
 306                 if(thread->TID == TID)
 307                         return thread;
 308         }
 309
 310         // Search Sleeping List
 311         for(thread = gSleepingThreads;
 312                 thread;
 313                 thread = thread->Next)
 314         {
 315                 if(thread->TID == TID)
 316                         return thread;
 317         }
 318
 319         return NULL;
 320 }
 321
 322 /**
 323  * \fn void Threads_AddToDelete(tThread *Thread)
 324  * \brief Adds a thread to the delete queue
 325  */
 326 void Threads_AddToDelete(tThread *Thread)
 327 {
 328         // Add to delete queue
 329         if(gDeleteThreads) {
 330                 Thread->Next = gDeleteThreads;
 331                 gDeleteThreads = Thread;
 332         } else {
 333                 Thread->Next = NULL;
 334                 gDeleteThreads = Thread;
 335         }
 336 }
 337
 338 /**
 339  * \fn tThread *Threads_int_GetPrev(tThread **List, tThread *Thread)
 340  * \brief Gets the previous entry in a thead linked list
 341  */
 342 tThread *Threads_int_GetPrev(tThread **List, tThread *Thread)
 343 {
 344         tThread *ret;
 345         // First Entry
 346         if(*List == Thread) {
 347                 return (tThread*)List;
 348         } else {
 349                 for(ret = *List;
 350                         ret->Next && ret->Next != Thread;
 351                         ret = ret->Next
 352                         );
 353                 // Error if the thread is not on the list
 354                 if(!ret->Next || ret->Next != Thread) {
 355                         return NULL;
 356                 }
 357         }
 358         return ret;
 359 }
 360
 361 /**
 362  * \fn void Threads_Exit(int TID, int Status)
 363  * \brief Exit the current process
 364  */
 365 void Threads_Exit(int TID, int Status)
 366 {
 367         if( TID == 0 )
 368                 Threads_Kill( Proc_GetCurThread(), (Uint)Status & 0xFF );
 369         else
 370                 Threads_Kill( Threads_GetThread(TID), (Uint)Status & 0xFF );
 371         for(;;) HALT(); // Just in case
 372 }
 373
 374 /**
 375  * \fn void Threads_Kill(tThread *Thread, int Status)
 376  * \brief Kill a thread
 377  * \param Thread        Thread to kill
 378  * \param Status        Status code to return to the parent
 379  */
 380 void Threads_Kill(tThread *Thread, int Status)
 381 {
 382         tThread *prev;
 383         tMsg    *msg;
 384
 385         // Kill all children
 386         #if 0
 387         {
 388                 tThread *child;
 389                 for(child = gActiveThreads;
 390                         child;
 391                         child = child->Next)
 392                 {
 393                         if(child->PTID == Thread->TID)
 394                                 Threads_Kill(child, -1);
 395                 }
 396         }
 397         #endif
 398
 399         ///\note Double lock is needed due to overlap of locks
 400
 401         // Lock thread (stop us recieving messages)
 402         LOCK( &Thread->IsLocked );
 403
 404         // Lock thread list
 405         LOCK( &glThreadListLock );
 406
 407         // Get previous thread on list
 408         prev = Threads_int_GetPrev( &gActiveThreads, Thread );
 409         if(!prev) {
 410                 Warning("Proc_Exit - Current thread is not on the active queue");
 411                 return;
 412         }
 413
 414         // Clear Message Queue
 415         while( Thread->Messages )
 416         {
 417                 msg = Thread->Messages->Next;
 418                 free( Thread->Messages );
 419                 Thread->Messages = msg;
 420         }
 421
 422         Thread->Remaining = 0;  // Clear Remaining Quantum
 423         Thread->Quantum = 0;    // Clear Quantum to indicate dead thread
 424         prev->Next = Thread->Next;      // Remove from active
 425
 426         giNumActiveThreads --;
 427         giTotalTickets -= Thread->NumTickets;
 428
 429         // Mark thread as a zombie
 430         Thread->RetStatus = Status;
 431
 432         // Don't Zombie if we are being killed as part of a tree
 433         if(Status == -1)
 434         {
 435                 Thread->Status = THREAD_STAT_DEAD;
 436                 Threads_AddToDelete( Thread );
 437         } else {
 438                 Thread->Status = THREAD_STAT_ZOMBIE;
 439         }
 440
 441         // Release spinlocks
 442         RELEASE( &Thread->IsLocked );   // Released first so that it IS released
 443         RELEASE( &glThreadListLock );
 444
 445         //Log("Thread %i went *hurk*", Thread->TID);
 446
 447         if(Status != -1)        HALT();
 448 }
 449
 450 /**
 451  * \fn void Threads_Yield(void)
 452  * \brief Yield remainder of timeslice
 453  */
 454 void Threads_Yield(void)
 455 {
 456         Proc_GetCurThread()->Remaining = 0;
 457         HALT();
 458 }
 459
 460 /**
 461  * \fn void Threads_Sleep(void)
 462  * \brief Take the current process off the run queue
 463  */
 464 void Threads_Sleep(void)
 465 {
 466         tThread *cur = Proc_GetCurThread();
 467         tThread *thread;
 468
 469         //Log_Log("Threads", "%i going to sleep", cur->TID);
 470
 471         // Acquire Spinlock
 472         LOCK( &glThreadListLock );
 473
 474         // Get thread before current thread
 475         thread = Threads_int_GetPrev( &gActiveThreads, cur );
 476         if(!thread) {
 477                 Warning("Threads_Sleep - Current thread is not on the active queue");
 478                 Threads_Dump();
 479                 return;
 480         }
 481
 482         // Don't sleep if there is a message waiting
 483         if( cur->Messages ) {
 484                 RELEASE( &glThreadListLock );
 485                 return;
 486         }
 487
 488         // Unset remaining timeslices (force a task switch on timer fire)
 489         cur->Remaining = 0;
 490
 491         // Remove from active list
 492         thread->Next = cur->Next;
 493
 494         // Add to Sleeping List (at the top)
 495         cur->Next = gSleepingThreads;
 496         gSleepingThreads = cur;
 497
 498         // Reduce the active count & ticket count
 499         giNumActiveThreads --;
 500         giTotalTickets -= cur->NumTickets;
 501
 502         // Mark thread as sleeping
 503         cur->Status = THREAD_STAT_SLEEPING;
 504
 505         // Release Spinlock
 506         RELEASE( &glThreadListLock );
 507
 508         while(cur->Status != THREAD_STAT_ACTIVE)        HALT();
 509 }
 510
 511
 512 /**
 513  * \fn void Threads_Wake( tThread *Thread )
 514  * \brief Wakes a sleeping/waiting thread up
 515  */
 516 void Threads_Wake(tThread *Thread)
 517 {
 518         tThread *prev;
 519         switch(Thread->Status)
 520         {
 521         case THREAD_STAT_ACTIVE:        break;
 522         case THREAD_STAT_SLEEPING:
 523                 //Log_Log("Threads", "Waking %i (%p) from sleeping", Thread->TID, Thread);
 524                 LOCK( &glThreadListLock );
 525                 prev = Threads_int_GetPrev(&gSleepingThreads, Thread);
 526                 prev->Next = Thread->Next;      // Remove from sleeping queue
 527                 Thread->Next = gActiveThreads;  // Add to active queue
 528                 gActiveThreads = Thread;
 529                 giNumActiveThreads ++;
 530                 giTotalTickets += Thread->NumTickets;
 531                 Thread->Status = THREAD_STAT_ACTIVE;
 532                 RELEASE( &glThreadListLock );
 533                 break;
 534         case THREAD_STAT_WAITING:
 535                 Warning("Thread_Wake - Waiting threads are not currently supported");
 536                 break;
 537         case THREAD_STAT_DEAD:
 538                 Warning("Thread_Wake - Attempt to wake dead thread (%i)", Thread->TID);
 539                 break;
 540         default:
 541                 Warning("Thread_Wake - Unknown process status (%i)\n", Thread->Status);
 542                 break;
 543         }
 544 }
 545
 546 void Threads_WakeTID(tTID Thread)
 547 {
 548         Threads_Wake( Threads_GetThread(Thread) );
 549 }
 550
 551 /**
 552  * \fn void Threads_AddActive(tThread *Thread)
 553  * \brief Adds a thread to the active queue
 554  */
 555 void Threads_AddActive(tThread *Thread)
 556 {
 557         LOCK( &glThreadListLock );
 558         Thread->Next = gActiveThreads;
 559         gActiveThreads = Thread;
 560         giNumActiveThreads ++;
 561         giTotalTickets += Thread->NumTickets;
 562         //Log("Threads_AddActive: giNumActiveThreads = %i, giTotalTickets = %i",
 563         //      giNumActiveThreads, giTotalTickets);
 564         RELEASE( &glThreadListLock );
 565 }
 566
 567 /**
 568  * \fn void Threads_SetFaultHandler(Uint Handler)
 569  * \brief Sets the signal handler for a signal
 570  */
 571 void Threads_SetFaultHandler(Uint Handler)
 572 {
 573         Log_Log("Threads", "Threads_SetFaultHandler: Handler = %p", Handler);
 574         Proc_GetCurThread()->FaultHandler = Handler;
 575 }
 576
 577 /**
 578  * \fn void Threads_Fault(int Num)
 579  * \brief Calls a fault handler
 580  */
 581 void Threads_Fault(int Num)
 582 {
 583         tThread *thread = Proc_GetCurThread();
 584
 585         Log_Log("Threads", "Threads_Fault: thread = %p", thread);
 586
 587         if(!thread)     return ;
 588
 589         Log_Log("Threads", "Threads_Fault: thread->FaultHandler = %p", thread->FaultHandler);
 590
 591         switch(thread->FaultHandler)
 592         {
 593         case 0: // Panic?
 594                 Threads_Kill(thread, -1);
 595                 HALT();
 596                 return ;
 597         case 1: // Dump Core?
 598                 Threads_Kill(thread, -1);
 599                 HALT();
 600                 return ;
 601         }
 602
 603         // Double Fault? Oh, F**k
 604         if(thread->CurFaultNum != 0) {
 605                 Threads_Kill(thread, -1);       // For now, just kill
 606                 HALT();
 607         }
 608
 609         thread->CurFaultNum = Num;
 610
 611         Proc_CallFaultHandler(thread);
 612 }
 613
 614 // --- Process Structure Access Functions ---
 615 tPID Threads_GetPID(void)
 616 {
 617         return Proc_GetCurThread()->TGID;
 618 }
 619 tTID Threads_GetTID(void)
 620 {
 621         return Proc_GetCurThread()->TID;
 622 }
 623 tUID Threads_GetUID(void)
 624 {
 625         return Proc_GetCurThread()->UID;
 626 }
 627 tGID Threads_GetGID(void)
 628 {
 629         return Proc_GetCurThread()->GID;
 630 }
 631
 632 int Threads_SetUID(Uint *Errno, tUID ID)
 633 {
 634         tThread *t = Proc_GetCurThread();
 635         if( t->UID != 0 ) {
 636                 *Errno = -EACCES;
 637                 return -1;
 638         }
 639         Log("Threads_SetUID - Setting User ID to %i", ID);
 640         t->UID = ID;
 641         return 0;
 642 }
 643
 644 int Threads_SetGID(Uint *Errno, tGID ID)
 645 {
 646         tThread *t = Proc_GetCurThread();
 647         if( t->UID != 0 ) {
 648                 *Errno = -EACCES;
 649                 return -1;
 650         }
 651         Log("Threads_SetGID - Setting Group ID to %i", ID);
 652         t->GID = ID;
 653         return 0;
 654 }
 655
 656 /**
 657  * \fn void Threads_Dump(void)
 658  * \brief Dums a list of currently running threads
 659  */
 660 void Threads_Dump(void)
 661 {
 662         tThread *thread;
 663         tThread *cur = Proc_GetCurThread();
 664
 665         Log("Active Threads:");
 666         for(thread=gActiveThreads;thread;thread=thread->Next)
 667         {
 668                 Log("%c%i (%i) - %s",
 669                         (thread==cur?'*':' '),
 670                         thread->TID, thread->TGID, thread->ThreadName);
 671                 Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
 672                 Log("  KStack 0x%x", thread->KernelStack);
 673         }
 674         Log("Sleeping Threads:");
 675         for(thread=gSleepingThreads;thread;thread=thread->Next)
 676         {
 677                 Log("%c%i (%i) - %s",
 678                         (thread==cur?'*':' '),
 679                         thread->TID, thread->TGID, thread->ThreadName);
 680                 Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
 681                 Log("  KStack 0x%x", thread->KernelStack);
 682         }
 683 }
 684
 685 /**
 686  * \fn tThread *Threads_GetNextToRun(int CPU)
 687  * \brief Gets the next thread to run
 688  */
 689 tThread *Threads_GetNextToRun(int CPU)
 690 {
 691         tThread *thread;
 692          int    ticket;
 693          int    number;
 694
 695         if(giNumActiveThreads == 0) {
 696                 return NULL;
 697         }
 698
 699         // Special case: 1 thread
 700         if(giNumActiveThreads == 1) {
 701                 return gActiveThreads;
 702         }
 703
 704         // Get the ticket number
 705         ticket = number = rand() % giTotalTickets;
 706
 707         // Find the next thread
 708         for(thread=gActiveThreads;thread;thread=thread->Next)
 709         {
 710                 if(thread->NumTickets > number) break;
 711                 number -= thread->NumTickets;
 712         }
 713
 714         // Error Check
 715         if(thread == NULL)
 716         {
 717                 number = 0;
 718                 for(thread=gActiveThreads;thread;thread=thread->Next)
 719                         number += thread->NumTickets;
 720                 Panic("Bookeeping Failed - giTotalTicketCount (%i) != true count (%i)",
 721                         giTotalTickets, number);
 722         }
 723
 724         return thread;
 725 }
 726
 727 /**
 728  * \fn void Threads_SegFault(tVAddr Addr)
 729  * \brief Called when a Segment Fault occurs
 730  */
 731 void Threads_SegFault(tVAddr Addr)
 732 {
 733         Warning("Thread #%i committed a segfault at address %p", Proc_GetCurThread()->TID, Addr);
 734         Threads_Fault( 1 );
 735         //Threads_Exit( 0, -1 );
 736 }
 737
 738 // === EXPORTS ===
 739 EXPORT(Threads_GetUID);