Kernel/threads.c

   1 /*
   2  * Acess2
   3  * threads.c
   4  * - Common Thread Control
   5  */
   6 #include <common.h>
   7 #include <threads.h>
   8
   9 // === CONSTANTS ===
  10 #define DEFAULT_QUANTUM 10
  11 #define DEFAULT_TICKETS 5
  12 #define MAX_TICKETS             10
  13
  14 // === IMPORTS ===
  15 extern void     ArchThreads_Init();
  16 extern void     Proc_Start();
  17 extern tThread  *Proc_GetCurThread();
  18 extern int      Proc_Clone(Uint *Err, Uint Flags);
  19
  20 // === PROTOTYPES ===
  21 void    Threads_Init();
  22 void    Threads_SetName(char *NewName);
  23 void    Threads_SetTickets(int Num);
  24  int    Threads_WaitTID(int TID, int *status);
  25 tThread *Threads_GetThread(Uint TID);
  26 void    Threads_AddToDelete(tThread *Thread);
  27 tThread *Threads_int_GetPrev(tThread **List, tThread *Thread);
  28 void    Threads_Exit(int TID, int Status);
  29 void    Threads_Kill(tThread *Thread, int Status);
  30 void    Threads_Yield();
  31 void    Threads_Sleep();
  32 void    Threads_Wake(tThread *Thread);
  33 void    Threads_AddActive(tThread *Thread);
  34  int    Threads_GetPID();
  35  int    Threads_GetTID();
  36  int    Threads_GetUID();
  37  int    Threads_GetGID();
  38 void    Threads_Dump();
  39
  40 // === GLOBALS ===
  41 // -- Core Thread --
  42 tThread gThreadZero = {
  43         NULL, 0,        // Next, Lock
  44         THREAD_STAT_ACTIVE,     // Status
  45         0,      // Exit Status
  46         0, 0,   // TID, TGID
  47         0, 0,   // UID, GID
  48         0,      // Parent Thread ID
  49         "ThreadZero",   // Name
  50
  51         0,      // Kernel Stack
  52         {0},    // Saved State
  53         {0},    // VM State
  54
  55         0, {0}, {0},    // Signal State
  56
  57         NULL, NULL,     // Messages, Last Message
  58         DEFAULT_QUANTUM, DEFAULT_QUANTUM,       // Quantum, Remaining
  59         DEFAULT_TICKETS,
  60         {0}     // Default config to zero
  61         };
  62 // -- Processes --
  63 // --- Locks ---
  64 volatile int    giThreadListLock = 0;   ///\note NEVER use a heap function while locked
  65 // --- Current State ---
  66 volatile int    giNumActiveThreads = 0;
  67 volatile int    giTotalTickets = 0;
  68 volatile Uint   giNextTID = 1;
  69 // --- Thread Lists ---
  70 tThread *gActiveThreads = NULL;         // Currently Running Threads
  71 tThread *gSleepingThreads = NULL;       // Sleeping Threads
  72 tThread *gDeleteThreads = NULL;         // Threads to delete
  73  int    giNumCPUs = 1;
  74
  75 // === CODE ===
  76 /**
  77  * \fn void Threads_Init()
  78  * \brief Initialse the thread list
  79  */
  80 void Threads_Init()
  81 {
  82         ArchThreads_Init();
  83
  84         // Create Initial Task
  85         gActiveThreads = &gThreadZero;
  86         giTotalTickets = gThreadZero.NumTickets;
  87         giNumActiveThreads = 1;
  88
  89         #if 1
  90         // Create Idle Task
  91         if(Proc_Clone(0, 0) == 0)
  92         {
  93                 tThread *cur = Proc_GetCurThread();
  94                 cur->ThreadName = "Idle Thread";
  95                 Threads_SetTickets(0);  // Never called randomly
  96                 cur->Quantum = 1;       // 1 slice quantum
  97                 HALT();
  98                 for(;;) {
  99                         HALT(); // Just yeilds
 100                 }
 101         }
 102         #endif
 103
 104         Proc_Start();
 105 }
 106
 107 /**
 108  * \fn void Threads_SetName(char *NewName)
 109  * \brief Sets the current thread's name
 110  */
 111 void Threads_SetName(char *NewName)
 112 {
 113         tThread *cur = Proc_GetCurThread();
 114         if( IsHeap(cur->ThreadName) )
 115                 free( cur->ThreadName );
 116         cur->ThreadName = malloc(strlen(NewName)+1);
 117         strcpy(cur->ThreadName, NewName);
 118 }
 119
 120 /**
 121  * \fn void Threads_SetTickets(int Num)
 122  * \brief Sets the 'priority' of a task
 123  */
 124 void Threads_SetTickets(int Num)
 125 {
 126         tThread *cur = Proc_GetCurThread();
 127         if(Num < 0)     return;
 128         if(Num > MAX_TICKETS)   Num = MAX_TICKETS;
 129
 130         LOCK( &giThreadListLock );
 131         giTotalTickets -= cur->NumTickets;
 132         cur->NumTickets = Num;
 133         giTotalTickets += Num;
 134         //LOG("giTotalTickets = %i", giTotalTickets);
 135         RELEASE( &giThreadListLock );
 136 }
 137
 138 /**
 139  * \fn void Threads_WaitTID(int TID, int *status)
 140  * \brief Wait for a task to change state
 141  */
 142 int Threads_WaitTID(int TID, int *status)
 143 {
 144         // Any Child
 145         if(TID == -1) {
 146
 147                 return -1;
 148         }
 149
 150         // Any peer/child thread
 151         if(TID == 0) {
 152
 153                 return -1;
 154         }
 155
 156         // TGID = abs(TID)
 157         if(TID < -1) {
 158                 return -1;
 159         }
 160
 161         // Specific Thread
 162         if(TID > 0) {
 163                 tThread *t = Threads_GetThread(TID);
 164                  int    initStatus = t->Status;
 165                  int    ret;
 166                 while(t->Status == initStatus)  Threads_Yield();
 167                 ret = t->RetStatus;
 168                 switch(t->Status)
 169                 {
 170                 case THREAD_STAT_ZOMBIE:
 171                         t->Status = THREAD_STAT_DEAD;
 172                         if(status)      *status = 0;
 173                         Threads_AddToDelete( t );
 174                         break;
 175                 default:
 176                         if(status)      *status = -1;
 177                         break;
 178                 }
 179                 return ret;
 180         }
 181
 182         return -1;
 183 }
 184
 185 /**
 186  * \fn tThread *Threads_GetThread(Uint TID)
 187  * \brief Gets a thread given its TID
 188  */
 189 tThread *Threads_GetThread(Uint TID)
 190 {
 191         tThread *thread;
 192
 193         // Search Active List
 194         for(thread = gActiveThreads;
 195                 thread;
 196                 thread = thread->Next)
 197         {
 198                 if(thread->TID == TID)
 199                         return thread;
 200         }
 201
 202         // Search Sleeping List
 203         for(thread = gSleepingThreads;
 204                 thread;
 205                 thread = thread->Next)
 206         {
 207                 if(thread->TID == TID)
 208                         return thread;
 209         }
 210
 211         return NULL;
 212 }
 213
 214 /**
 215  * \fn void Threads_AddToDelete(tThread *Thread)
 216  * \brief Adds a thread to the delete queue
 217  */
 218 void Threads_AddToDelete(tThread *Thread)
 219 {
 220         // Add to delete queue
 221         if(gDeleteThreads) {
 222                 Thread->Next = gDeleteThreads;
 223                 gDeleteThreads = Thread;
 224         } else {
 225                 Thread->Next = NULL;
 226                 gDeleteThreads = Thread;
 227         }
 228 }
 229
 230 /**
 231  * \fn tThread *Threads_int_GetPrev(tThread *List, tThread *Thread)
 232  * \brief Gets the previous entry in a thead linked list
 233  */
 234 tThread *Threads_int_GetPrev(tThread **List, tThread *Thread)
 235 {
 236         tThread *ret;
 237         // First Entry
 238         if(*List == Thread) {
 239                 return (tThread*)List;
 240         } else {
 241                 for(ret = *List;
 242                         ret->Next && ret->Next != Thread;
 243                         ret = ret->Next
 244                         );
 245                 // Error if the thread is not on the list
 246                 if(!ret->Next || ret->Next != Thread) {
 247                         return NULL;
 248                 }
 249         }
 250         return ret;
 251 }
 252
 253 /**
 254  * \fn void Threads_Exit(int TID, int Status)
 255  * \brief Exit the current process
 256  */
 257 void Threads_Exit(int TID, int Status)
 258 {
 259         if( TID == 0 )
 260                 Threads_Kill( Proc_GetCurThread(), (Uint)Status & 0xFF );
 261         else
 262                 Threads_Kill( Threads_GetThread(TID), (Uint)Status & 0xFF );
 263 }
 264
 265 /**
 266  * \fn void Threads_Kill(tThread *Thread, int Status)
 267  * \brief Kill a thread
 268  * \param TID   Thread ID (0 for current)
 269  */
 270 void Threads_Kill(tThread *Thread, int Status)
 271 {
 272         tThread *prev;
 273         tMsg    *msg;
 274
 275         // Kill all children
 276         #if 1
 277         {
 278                 tThread *child;
 279                 for(child = gActiveThreads;
 280                         child;
 281                         child = child->Next)
 282                 {
 283                         if(child->PTID == Thread->TID)
 284                                 Threads_Kill(child, -1);
 285                 }
 286         }
 287         #endif
 288
 289         ///\note Double lock is needed due to overlap of locks
 290
 291         // Lock thread (stop us recieving messages)
 292         LOCK( &Thread->IsLocked );
 293
 294         // Lock thread list
 295         LOCK( &giThreadListLock );
 296
 297         // Get previous thread on list
 298         prev = Threads_int_GetPrev( &gActiveThreads, Thread );
 299         if(!prev) {
 300                 Warning("Proc_Exit - Current thread is not on the active queue");
 301                 return;
 302         }
 303
 304         // Clear Message Queue
 305         while( Thread->Messages )
 306         {
 307                 msg = Thread->Messages->Next;
 308                 free( Thread->Messages );
 309                 Thread->Messages = msg;
 310         }
 311
 312         Thread->Remaining = 0;  // Clear Remaining Quantum
 313         Thread->Quantum = 0;    // Clear Quantum to indicate dead thread
 314         prev->Next = Thread->Next;      // Remove from active
 315
 316         giNumActiveThreads --;
 317         giTotalTickets -= Thread->NumTickets;
 318
 319         // Mark thread as a zombie
 320         Thread->RetStatus = Status;
 321
 322         // Don't Zombie if we are being killed as part of a tree
 323         if(Status == -1)
 324         {
 325                 Thread->Status = THREAD_STAT_DEAD;
 326                 Threads_AddToDelete( Thread );
 327         } else {
 328                 Thread->Status = THREAD_STAT_ZOMBIE;
 329         }
 330
 331         // Release spinlocks
 332         RELEASE( &Thread->IsLocked );   // Released first so that it IS released
 333         RELEASE( &giThreadListLock );
 334         if(Status != -1)        HALT();
 335 }
 336
 337 /**
 338  * \fn void Threads_Yield()
 339  * \brief Yield remainder of timeslice
 340  */
 341 void Threads_Yield()
 342 {
 343         Proc_GetCurThread()->Remaining = 0;
 344         HALT();
 345 }
 346
 347 /**
 348  * \fn void Threads_Sleep()
 349  * \brief Take the current process off the run queue
 350  */
 351 void Threads_Sleep()
 352 {
 353         tThread *cur = Proc_GetCurThread();
 354         tThread *thread;
 355
 356         Log("Proc_Sleep: %i going to sleep", cur->TID);
 357
 358         // Acquire Spinlock
 359         LOCK( &giThreadListLock );
 360
 361         // Get thread before current thread
 362         thread = Threads_int_GetPrev( &gActiveThreads, cur );
 363         if(!thread) {
 364                 Warning("Proc_Sleep - Current thread is not on the active queue");
 365                 return;
 366         }
 367
 368         // Don't sleep if there is a message waiting
 369         if( cur->Messages ) {
 370                 RELEASE( &giThreadListLock );
 371                 return;
 372         }
 373
 374         // Unset remaining timeslices (force a task switch on timer fire)
 375         cur->Remaining = 0;
 376
 377         // Remove from active list
 378         thread->Next = cur->Next;
 379
 380         // Add to Sleeping List (at the top)
 381         cur->Next = gSleepingThreads;
 382         gSleepingThreads = cur;
 383
 384         // Reduce the active count & ticket count
 385         giNumActiveThreads --;
 386         giTotalTickets -= cur->NumTickets;
 387
 388         // Mark thread as sleeping
 389         cur->Status = THREAD_STAT_SLEEPING;
 390
 391         // Release Spinlock
 392         RELEASE( &giThreadListLock );
 393
 394         HALT();
 395 }
 396
 397
 398 /**
 399  * \fn void Threads_Wake( tThread *Thread )
 400  * \brief Wakes a sleeping/waiting thread up
 401  */
 402 void Threads_Wake(tThread *Thread)
 403 {
 404         tThread *prev;
 405         switch(Thread->Status)
 406         {
 407         case THREAD_STAT_ACTIVE:        break;
 408         case THREAD_STAT_SLEEPING:
 409                 LOCK( &giThreadListLock );
 410                 prev = Threads_int_GetPrev(&gSleepingThreads, Thread);
 411                 prev->Next = Thread->Next;      // Remove from sleeping queue
 412                 Thread->Next = gActiveThreads;  // Add to active queue
 413                 gActiveThreads = Thread;
 414                 Thread->Status = THREAD_STAT_ACTIVE;
 415                 RELEASE( &giThreadListLock );
 416                 break;
 417         case THREAD_STAT_WAITING:
 418                 Warning("Thread_Wake - Waiting threads are not currently supported");
 419                 break;
 420         case THREAD_STAT_DEAD:
 421                 Warning("Thread_Wake - Attempt to wake dead thread (%i)", Thread->TID);
 422                 break;
 423         default:
 424                 Warning("Thread_Wake - Unknown process status (%i)\n", Thread->Status);
 425                 break;
 426         }
 427 }
 428
 429 /**
 430  * \fn void Threads_AddActive(tThread *Thread)
 431  * \brief Adds a thread to the active queue
 432  */
 433 void Threads_AddActive(tThread *Thread)
 434 {
 435         LOCK( &giThreadListLock );
 436         Thread->Next = gActiveThreads;
 437         gActiveThreads = Thread;
 438         giNumActiveThreads ++;
 439         giTotalTickets += Thread->NumTickets;
 440         //Log("Threads_AddActive: giNumActiveThreads = %i, giTotalTickets = %i",
 441         //      giNumActiveThreads, giTotalTickets);
 442         RELEASE( &giThreadListLock );
 443 }
 444
 445 #if 0
 446 /**
 447  * \fn void Threads_SetSignalHandler(int Num, void *Handler)
 448  * \brief Sets the signal handler for a signal
 449  */
 450 void Threads_SetSignalHandler(int Num, void *Handler)
 451 {
 452         if(Num < 0 || Num >= NSIG)      return;
 453
 454         gCurrentThread->SignalHandlers[Num] = Handler;
 455 }
 456
 457 /**
 458  * \fn void Threads_SendSignal(int TID, int Num)
 459  * \brief Send a signal to a thread
 460  */
 461 void Threads_SendSignal(int TID, int Num)
 462 {
 463         tThread *thread = Proc_GetThread(TID);
 464         void    *handler;
 465
 466         if(!thread)     return ;
 467
 468         handler = thread->SignalHandlers[Num];
 469
 470         // Panic?
 471         if(handler == SIG_ERR) {
 472                 Proc_Kill(TID);
 473                 return ;
 474         }
 475         // Dump Core?
 476         if(handler == -2) {
 477                 Proc_Kill(TID);
 478                 return ;
 479         }
 480         // Ignore?
 481         if(handler == -2)       return;
 482
 483         // Check the type and handle if the thread is already in a signal
 484         if(thread->CurSignal != 0) {
 485                 if(Num < _SIGTYPE_FATAL)
 486                         Proc_Kill(TID);
 487                 } else {
 488                         while(thread->CurSignal != 0)
 489                                 Proc_Yield();
 490                 }
 491         }
 492
 493         //TODO:
 494 }
 495 #endif
 496
 497 // --- Process Structure Access Functions ---
 498 int Threads_GetPID()
 499 {
 500         return Proc_GetCurThread()->TGID;
 501 }
 502 int Threads_GetTID()
 503 {
 504         return Proc_GetCurThread()->TID;
 505 }
 506 int Threads_GetUID()
 507 {
 508         return Proc_GetCurThread()->UID;
 509 }
 510 int Threads_GetGID()
 511 {
 512         return Proc_GetCurThread()->GID;
 513 }
 514
 515 /**
 516  * \fn void Threads_Dump()
 517  * \brief Dums a list of currently running threads
 518  */
 519 void Threads_Dump()
 520 {
 521         tThread *thread;
 522
 523         Log("Active Threads:");
 524         for(thread=gActiveThreads;thread;thread=thread->Next)
 525         {
 526                 Log(" %i (%i) - %s", thread->TID, thread->TGID, thread->ThreadName);
 527                 Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
 528                 Log("  KStack 0x%x", thread->KernelStack);
 529         }
 530         Log("Sleeping Threads:");
 531         for(thread=gSleepingThreads;thread;thread=thread->Next)
 532         {
 533                 Log(" %i (%i) - %s", thread->TID, thread->TGID, thread->ThreadName);
 534                 Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
 535                 Log("  KStack 0x%x", thread->KernelStack);
 536         }
 537 }
 538
 539 /**
 540  * \fn tThread *Threads_GetNextToRun(int CPU)
 541  * \brief Gets the next thread to run
 542  */
 543 tThread *Threads_GetNextToRun(int CPU)
 544 {
 545         tThread *thread;
 546          int    ticket;
 547          int    number;
 548
 549         // Special case: 1 thread
 550         if(giNumActiveThreads == 1)
 551         {
 552                 return gActiveThreads;
 553         }
 554
 555         //Log(" Threads_GetNextToRun: giNumActiveThreads=%i,giTotalTickets=%i",
 556         //      giNumActiveThreads, giTotalTickets);
 557         // Get the ticket number
 558         ticket = number = rand() % giTotalTickets;
 559
 560         //Log(" Threads_GetNextToRun: ticket = %i", ticket);
 561
 562         // Find the next thread
 563         for(thread=gActiveThreads;thread;thread=thread->Next)
 564         {
 565                 if(thread->NumTickets > number) break;
 566                 number -= thread->NumTickets;
 567         }
 568
 569         // Error Check
 570         if(thread == NULL)
 571         {
 572                 number = 0;
 573                 for(thread=gActiveThreads;thread;thread=thread->Next)
 574                         number += thread->NumTickets;
 575                 Panic("Bookeeping Failed - giTotalTicketCount (%i) != true count (%i)",
 576                         giTotalTickets, number);
 577         }
 578
 579         return thread;
 580 }
 581
 582 /**
 583  * \fn void Threads_SegFault(tVAddr Addr)
 584  * \brief Called when a Segment Fault occurs
 585  */
 586 void Threads_SegFault(tVAddr Addr)
 587 {
 588         //Threads_SendSignal( Proc_GetCurThread()->TID, SIGSEGV );
 589         Threads_Kill( Proc_GetCurThread(), 0 );
 590 }