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 #define DEBUG_TRACE_TICKETS     0       // Trace ticket counts
  11 #define DEBUG_TRACE_STATE       0       // Trace state changes (sleep/wake)
  12
  13 // === CONSTANTS ===
  14 #define DEFAULT_QUANTUM 10
  15 #define DEFAULT_TICKETS 5
  16 #define MAX_TICKETS             10
  17 const enum eConfigTypes cCONFIG_TYPES[] = {
  18         CFGT_HEAPSTR,   // e.g. CFG_VFS_CWD
  19         CFGT_INT,       // e.g. CFG_VFS_MAXFILES
  20         CFGT_NULL
  21 };
  22
  23 // === IMPORTS ===
  24 extern void     ArchThreads_Init(void);
  25 extern void     Proc_Start(void);
  26 extern tThread  *Proc_GetCurThread(void);
  27 extern int      Proc_Clone(Uint *Err, Uint Flags);
  28 extern void     Proc_CallFaultHandler(tThread *Thread);
  29
  30 // === PROTOTYPES ===
  31 void    Threads_Init(void);
  32  int    Threads_SetName(char *NewName);
  33 char    *Threads_GetName(int ID);
  34 void    Threads_SetTickets(tThread *Thread, int Num);
  35 tThread *Threads_CloneTCB(Uint *Err, Uint Flags);
  36  int    Threads_WaitTID(int TID, int *status);
  37 tThread *Threads_GetThread(Uint TID);
  38 void    Threads_AddToDelete(tThread *Thread);
  39 tThread *Threads_int_GetPrev(tThread **List, tThread *Thread);
  40 void    Threads_Exit(int TID, int Status);
  41 void    Threads_Kill(tThread *Thread, int Status);
  42 void    Threads_Yield(void);
  43 void    Threads_Sleep(void);
  44  int    Threads_Wake(tThread *Thread);
  45 void    Threads_AddActive(tThread *Thread);
  46 void    Threads_int_AddActive(tThread *Thread);
  47 tThread *Threads_RemActive(void);
  48  int    Threads_GetPID(void);
  49  int    Threads_GetTID(void);
  50 tUID    Threads_GetUID(void);
  51  int    Threads_SetUID(Uint *Errno, tUID ID);
  52 tGID    Threads_GetGID(void);
  53  int    Threads_SetGID(Uint *Errno, tUID ID);
  54 void    Threads_Dump(void);
  55 void    Mutex_Acquire(tMutex *Mutex);
  56 void    Mutex_Release(tMutex *Mutex);
  57  int    Mutex_IsLocked(tMutex *Mutex);
  58
  59 // === GLOBALS ===
  60 // -- Core Thread --
  61 // Only used for the core kernel
  62 tThread gThreadZero = {
  63         Status: THREAD_STAT_ACTIVE,     // Status
  64         ThreadName:     "ThreadZero",   // Name
  65         Quantum: DEFAULT_QUANTUM,       // Default Quantum
  66         Remaining:      DEFAULT_QUANTUM,        // Current Quantum
  67         NumTickets:     DEFAULT_TICKETS // Number of tickets
  68         };
  69 // -- Processes --
  70 // --- Locks ---
  71 tShortSpinlock  glThreadListLock;       ///\note NEVER use a heap function while locked
  72 // --- Current State ---
  73 volatile int    giNumActiveThreads = 0; // Number of threads on the active queue
  74 volatile int    giFreeTickets = 0;      // Number of tickets held by non-scheduled threads
  75 volatile Uint   giNextTID = 1;  // Next TID to allocate
  76 // --- Thread Lists ---
  77 tThread *gAllThreads = NULL;            // All allocated threads
  78 tThread *gActiveThreads = NULL;         // Currently Running Threads
  79 tThread *gSleepingThreads = NULL;       // Sleeping Threads
  80 tThread *gDeleteThreads = NULL;         // Threads to delete
  81  int    giNumCPUs = 1;  // Number of CPUs
  82
  83 // === CODE ===
  84 /**
  85  * \fn void Threads_Init(void)
  86  * \brief Initialse the thread list
  87  */
  88 void Threads_Init(void)
  89 {
  90         ArchThreads_Init();
  91
  92         // Create Initial Task
  93         gActiveThreads = &gThreadZero;
  94         gAllThreads = &gThreadZero;
  95         //giFreeTickets = gThreadZero.NumTickets;       // Not needed, as ThreadZero is scheduled
  96         giNumActiveThreads = 1;
  97
  98         Proc_Start();
  99 }
 100
 101 /**
 102  * \fn void Threads_SetName(char *NewName)
 103  * \brief Sets the current thread's name
 104  * \param NewName       New name for the thread
 105  * \return Boolean Failure
 106  */
 107 int Threads_SetName(char *NewName)
 108 {
 109         tThread *cur = Proc_GetCurThread();
 110         char    *oldname = cur->ThreadName;
 111
 112         // NOTE: There is a possibility of non-thread safety here
 113         // A thread could read the current name pointer before it is zeroed
 114
 115         cur->ThreadName = NULL;
 116
 117         if( IsHeap(oldname) )   free( oldname );
 118
 119         cur->ThreadName = strdup(NewName);
 120         return 0;
 121 }
 122
 123 /**
 124  * \fn char *Threads_GetName(int ID)
 125  * \brief Gets a thread's name
 126  * \param ID    Thread ID (-1 indicates current thread)
 127  * \return Pointer to name
 128  * \retval NULL Failure
 129  */
 130 char *Threads_GetName(tTID ID)
 131 {
 132         if(ID == -1) {
 133                 return Proc_GetCurThread()->ThreadName;
 134         }
 135         return Threads_GetThread(ID)->ThreadName;
 136 }
 137
 138 /**
 139  * \fn void Threads_SetTickets(tThread *Thread, int Num)
 140  * \brief Sets the 'priority' of a task
 141  * \param Thread        Thread to update ticket count (NULL means current thread)
 142  * \param Num   New ticket count (must be >= 0, clipped to \a MAX_TICKETS)
 143  */
 144 void Threads_SetTickets(tThread *Thread, int Num)
 145 {
 146         // Get current thread
 147         if(Thread == NULL)      Thread = Proc_GetCurThread();
 148         // Bounds checking
 149         if(Num < 0)     return;
 150         if(Num > MAX_TICKETS)   Num = MAX_TICKETS;
 151
 152         // If this isn't the current thread, we need to lock
 153         if( Thread != Proc_GetCurThread() ) {
 154                 SHORTLOCK( &glThreadListLock );
 155                 giFreeTickets -= Thread->NumTickets - Num;
 156                 Thread->NumTickets = Num;
 157                 #if DEBUG_TRACE_TICKETS
 158                 Log("Threads_SetTickets: new giFreeTickets = %i", giFreeTickets);
 159                 #endif
 160                 SHORTREL( &glThreadListLock );
 161         }
 162         else
 163                 Thread->NumTickets = Num;
 164 }
 165
 166 /**
 167  * \fn tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
 168  * \brief Clone the TCB of the current thread
 169  * \param Err   Error pointer
 170  * \param Flags Flags for something... (What is this for?)
 171  */
 172 tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
 173 {
 174         tThread *cur, *new;
 175          int    i;
 176         cur = Proc_GetCurThread();
 177
 178         // Allocate and duplicate
 179         new = malloc(sizeof(tThread));
 180         if(new == NULL) {
 181                 *Err = -ENOMEM;
 182                 return NULL;
 183         }
 184         memcpy(new, cur, sizeof(tThread));
 185
 186         new->CurCPU = -1;
 187         new->Next = NULL;
 188         memset( &new->IsLocked, 0, sizeof(new->IsLocked));
 189         new->Status = THREAD_STAT_PREINIT;
 190         new->RetStatus = 0;
 191
 192         // Get Thread ID
 193         new->TID = giNextTID++;
 194         new->Parent = cur;
 195
 196         // Clone Name
 197         new->ThreadName = strdup(cur->ThreadName);
 198
 199         // Set Thread Group ID (PID)
 200         if(Flags & CLONE_VM)
 201                 new->TGID = new->TID;
 202         else
 203                 new->TGID = cur->TGID;
 204
 205         // Messages are not inherited
 206         new->Messages = NULL;
 207         new->LastMessage = NULL;
 208
 209         // Set State
 210         new->Remaining = new->Quantum = cur->Quantum;
 211         new->NumTickets = cur->NumTickets;
 212
 213         // Set Signal Handlers
 214         new->CurFaultNum = 0;
 215         new->FaultHandler = cur->FaultHandler;
 216
 217         for( i = 0; i < NUM_CFG_ENTRIES; i ++ )
 218         {
 219                 switch(cCONFIG_TYPES[i])
 220                 {
 221                 default:
 222                         new->Config[i] = cur->Config[i];
 223                         break;
 224                 case CFGT_HEAPSTR:
 225                         if(cur->Config[i])
 226                                 new->Config[i] = (Uint) strdup( (void*)cur->Config[i] );
 227                         else
 228                                 new->Config[i] = 0;
 229                         break;
 230                 }
 231         }
 232
 233         // Maintain a global list of threads
 234         SHORTLOCK( &glThreadListLock );
 235         new->GlobalPrev = NULL; // Protect against bugs
 236         new->GlobalNext = gAllThreads;
 237         gAllThreads = new;
 238         SHORTREL( &glThreadListLock );
 239
 240         return new;
 241 }
 242
 243 /**
 244  * \brief Get a configuration pointer from the Per-Thread data area
 245  * \param ID    Config slot ID
 246  * \return Pointer at ID
 247  */
 248 Uint *Threads_GetCfgPtr(int ID)
 249 {
 250         if(ID < 0 || ID >= NUM_CFG_ENTRIES) {
 251                 Warning("Threads_GetCfgPtr: Index %i is out of bounds", ID);
 252                 return NULL;
 253         }
 254
 255         return &Proc_GetCurThread()->Config[ID];
 256 }
 257
 258 /**
 259  * \brief Wait for a task to change state
 260  * \param TID   Thread ID to wait on (-1: Any child thread, 0: Any Child/Sibling, <-1: -PID)
 261  * \param Status        Thread return status
 262  * \return TID of child that changed state
 263  */
 264 tTID Threads_WaitTID(int TID, int *Status)
 265 {
 266         // Any Child
 267         if(TID == -1) {
 268                 Log_Error("Threads", "TODO: Threads_WaitTID(TID=-1) - Any Child");
 269                 return -1;
 270         }
 271
 272         // Any peer/child thread
 273         if(TID == 0) {
 274                 Log_Error("Threads", "TODO: Threads_WaitTID(TID=0) - Any Child/Sibling");
 275                 return -1;
 276         }
 277
 278         // TGID = abs(TID)
 279         if(TID < -1) {
 280                 Log_Error("Threads", "TODO: Threads_WaitTID(TID<0) - TGID");
 281                 return -1;
 282         }
 283
 284         // Specific Thread
 285         if(TID > 0) {
 286                 tThread *t = Threads_GetThread(TID);
 287                  int    initStatus = t->Status;
 288                 tTID    ret;
 289
 290                 // Wait for the thread to die!
 291                 if(initStatus != THREAD_STAT_ZOMBIE) {
 292                         // TODO: Handle child also being suspended if wanted
 293                         while(t->Status != THREAD_STAT_ZOMBIE) {
 294                                 Threads_Sleep();
 295                                 Log_Debug("Threads", "%i waiting for %i, t->Status = %i",
 296                                         Threads_GetTID(), t->TID, t->Status);
 297                         }
 298                 }
 299
 300                 // Set return status
 301                 Log_Debug("Threads", "%i waiting for %i, t->Status = %i",
 302                         Threads_GetTID(), t->TID, t->Status);
 303                 ret = t->TID;
 304                 switch(t->Status)
 305                 {
 306                 case THREAD_STAT_ZOMBIE:
 307                         // Kill the thread
 308                         t->Status = THREAD_STAT_DEAD;
 309                         // TODO: Child return value?
 310                         if(Status)      *Status = t->RetStatus;
 311                         // add to delete queue
 312                         Threads_AddToDelete( t );
 313                         break;
 314                 default:
 315                         if(Status)      *Status = -1;
 316                         break;
 317                 }
 318                 return ret;
 319         }
 320
 321         return -1;
 322 }
 323
 324 /**
 325  * \brief Gets a thread given its TID
 326  * \param TID   Thread ID
 327  * \return Thread pointer
 328  */
 329 tThread *Threads_GetThread(Uint TID)
 330 {
 331         tThread *thread;
 332
 333         // Search global list
 334         for(thread = gAllThreads;
 335                 thread;
 336                 thread = thread->GlobalNext)
 337         {
 338                 if(thread->TID == TID)
 339                         return thread;
 340         }
 341
 342         Log("Unable to find TID %i on main list\n", TID);
 343
 344         return NULL;
 345 }
 346
 347 /**
 348  * \brief Adds a thread to the delete queue
 349  * \param Thread        Thread to delete
 350  */
 351 void Threads_AddToDelete(tThread *Thread)
 352 {
 353         // Add to delete queue
 354         // TODO: Is locking needed?
 355         if(gDeleteThreads) {
 356                 Thread->Next = gDeleteThreads;
 357                 gDeleteThreads = Thread;
 358         } else {
 359                 Thread->Next = NULL;
 360                 gDeleteThreads = Thread;
 361         }
 362 }
 363
 364 /**
 365  * \brief Gets the previous entry in a thead linked list
 366  * \param List  Pointer to the list head
 367  * \param Thread        Thread to find
 368  * \return Thread before \a Thread on \a List
 369  * \note This uses a massive hack of assuming that the first field in the
 370  *       structure is the .Next pointer. By doing this, we can return \a List
 371  *       as a (tThread*) and simplify other code.
 372  */
 373 tThread *Threads_int_GetPrev(tThread **List, tThread *Thread)
 374 {
 375         tThread *ret;
 376         // First Entry
 377         if(*List == Thread) {
 378                 return (tThread*)List;
 379         }
 380         // Or not
 381         else {
 382                 for(ret = *List;
 383                         ret->Next && ret->Next != Thread;
 384                         ret = ret->Next
 385                         );
 386                 // Error if the thread is not on the list
 387                 if(!ret->Next || ret->Next != Thread) {
 388                         return NULL;
 389                 }
 390         }
 391         return ret;
 392 }
 393
 394 /**
 395  * \brief Exit the current process (or another?)
 396  * \param TID   Thread ID to kill
 397  * \param Status        Exit status
 398  */
 399 void Threads_Exit(int TID, int Status)
 400 {
 401         if( TID == 0 )
 402                 Threads_Kill( Proc_GetCurThread(), (Uint)Status & 0xFF );
 403         else
 404                 Threads_Kill( Threads_GetThread(TID), (Uint)Status & 0xFF );
 405
 406         // Halt forever, just in case
 407         for(;;) HALT();
 408 }
 409
 410 /**
 411  * \fn void Threads_Kill(tThread *Thread, int Status)
 412  * \brief Kill a thread
 413  * \param Thread        Thread to kill
 414  * \param Status        Status code to return to the parent
 415  */
 416 void Threads_Kill(tThread *Thread, int Status)
 417 {
 418         tThread *prev;
 419         tMsg    *msg;
 420
 421         // TODO: Kill all children
 422         #if 0
 423         {
 424                 tThread *child;
 425                 // TODO: I should keep a .Parent pointer, and a .Children list
 426                 for(child = gActiveThreads;
 427                         child;
 428                         child = child->Next)
 429                 {
 430                         if(child->PTID == Thread->TID)
 431                                 Threads_Kill(child, -1);
 432                 }
 433         }
 434         #endif
 435
 436         ///\note Double lock is needed due to overlap of lock areas
 437
 438         // Lock thread (stop us recieving messages)
 439         SHORTLOCK( &Thread->IsLocked );
 440
 441         // Lock thread list
 442         SHORTLOCK( &glThreadListLock );
 443
 444         // Get previous thread on list
 445         prev = Threads_int_GetPrev( &gActiveThreads, Thread );
 446         if(!prev) {
 447                 Warning("Proc_Exit - Current thread is not on the active queue");
 448                 SHORTREL( &glThreadListLock );
 449                 SHORTREL( &Thread->IsLocked );
 450                 return;
 451         }
 452
 453         // Clear Message Queue
 454         while( Thread->Messages )
 455         {
 456                 msg = Thread->Messages->Next;
 457                 free( Thread->Messages );       // BIG NO-NO
 458                 Thread->Messages = msg;
 459         }
 460
 461         // Ensure that we are not rescheduled
 462         Thread->Remaining = 0;  // Clear Remaining Quantum
 463         Thread->Quantum = 0;    // Clear Quantum to indicate dead thread
 464         prev->Next = Thread->Next;      // Remove from active
 465
 466         // Update bookkeeping
 467         giNumActiveThreads --;
 468         if( Thread != Proc_GetCurThread() )
 469                 giFreeTickets -= Thread->NumTickets;
 470
 471         // Save exit status
 472         Thread->RetStatus = Status;
 473
 474         // Don't Zombie if we are being killed because our parent is
 475         if(Status == -1)
 476         {
 477                 Thread->Status = THREAD_STAT_DEAD;
 478                 Threads_AddToDelete( Thread );
 479         } else {
 480                 Thread->Status = THREAD_STAT_ZOMBIE;
 481                 // Wake parent
 482                 Threads_Wake( Thread->Parent );
 483         }
 484
 485         Log("Thread %i went *hurk* (%i)", Thread->TID, Thread->Status);
 486
 487         // Release spinlocks
 488         SHORTREL( &glThreadListLock );
 489         SHORTREL( &Thread->IsLocked );  // TODO: We may not actually be released...
 490
 491         // And, reschedule
 492         if(Status != -1) {
 493                 for( ;; )
 494                         HALT();
 495         }
 496 }
 497
 498 /**
 499  * \brief Yield remainder of the current thread's timeslice
 500  */
 501 void Threads_Yield(void)
 502 {
 503         tThread *thread = Proc_GetCurThread();
 504         thread->Remaining = 0;
 505         //while(thread->Remaining == 0)
 506                 HALT();
 507 }
 508
 509 /**
 510  * \fn void Threads_Sleep(void)
 511  * \brief Take the current process off the run queue
 512  */
 513 void Threads_Sleep(void)
 514 {
 515         tThread *cur = Proc_GetCurThread();
 516
 517         // Acquire Spinlock
 518         SHORTLOCK( &glThreadListLock );
 519
 520         // Don't sleep if there is a message waiting
 521         if( cur->Messages ) {
 522                 SHORTREL( &glThreadListLock );
 523                 return;
 524         }
 525
 526         // Remove us from running queue
 527         Threads_RemActive();
 528         // Mark thread as sleeping
 529         cur->Status = THREAD_STAT_SLEEPING;
 530
 531         // Add to Sleeping List (at the top)
 532         cur->Next = gSleepingThreads;
 533         gSleepingThreads = cur;
 534
 535
 536         #if DEBUG_TRACE_STATE
 537         Log("Threads_Sleep: %p (%i %s) sleeping", cur, cur->TID, cur->ThreadName);
 538         #endif
 539
 540         // Release Spinlock
 541         SHORTREL( &glThreadListLock );
 542
 543         while(cur->Status != THREAD_STAT_ACTIVE)        HALT();
 544 }
 545
 546
 547 /**
 548  * \fn int Threads_Wake( tThread *Thread )
 549  * \brief Wakes a sleeping/waiting thread up
 550  * \param Thread        Thread to wake
 551  * \return Boolean Failure (Returns ERRNO)
 552  * \warning This should ONLY be called with task switches disabled
 553  */
 554 int Threads_Wake(tThread *Thread)
 555 {
 556         tThread *prev;
 557
 558         if(!Thread)
 559                 return -EINVAL;
 560
 561         switch(Thread->Status)
 562         {
 563         case THREAD_STAT_ACTIVE:
 564                 Log("Thread_Wake: Waking awake thread (%i)", Thread->TID);
 565                 return -EALREADY;
 566
 567         case THREAD_STAT_SLEEPING:
 568                 // Remove from sleeping queue
 569                 prev = Threads_int_GetPrev(&gSleepingThreads, Thread);
 570                 prev->Next = Thread->Next;
 571
 572                 Threads_int_AddActive( Thread );
 573
 574                 #if DEBUG_TRACE_STATE
 575                 Log("Threads_Sleep: %p (%i %s) woken", Thread, Thread->TID, Thread->ThreadName);
 576                 #endif
 577                 return -EOK;
 578
 579         case THREAD_STAT_WAITING:
 580                 Warning("Thread_Wake - Waiting threads are not currently supported");
 581                 return -ENOTIMPL;
 582
 583         case THREAD_STAT_DEAD:
 584                 Warning("Thread_Wake - Attempt to wake dead thread (%i)", Thread->TID);
 585                 return -ENOTIMPL;
 586
 587         default:
 588                 Warning("Thread_Wake - Unknown process status (%i)\n", Thread->Status);
 589                 return -EINTERNAL;
 590         }
 591 }
 592
 593 /**
 594  * \brief Wake a thread given the TID
 595  * \param TID   Thread ID to wake
 596  * \return Boolean Faulure (errno)
 597  */
 598 int Threads_WakeTID(tTID TID)
 599 {
 600         tThread *thread = Threads_GetThread(TID);
 601          int    ret;
 602         if(!thread)
 603                 return -ENOENT;
 604         SHORTLOCK( &glThreadListLock );
 605         ret = Threads_Wake( thread );
 606         SHORTREL( &glThreadListLock );
 607         //Log_Debug("Threads", "TID %i woke %i (%p)", Threads_GetTID(), TID, thread);
 608         return ret;
 609 }
 610
 611 /**
 612  * \brief Adds a thread to the active queue
 613  */
 614 void Threads_AddActive(tThread *Thread)
 615 {
 616         SHORTLOCK( &glThreadListLock );
 617         Threads_int_AddActive(Thread);
 618         SHORTREL( &glThreadListLock );
 619 }
 620
 621 /**
 622  * \brief Adds a thread to the active queue
 623  * \note This version MUST have the thread list lock held
 624  */
 625 void Threads_int_AddActive(tThread *Thread)
 626 {
 627         // Add to active list
 628         Thread->Next = gActiveThreads;
 629         gActiveThreads = Thread;
 630         // Set state
 631         Thread->Status = THREAD_STAT_ACTIVE;
 632         Thread->CurCPU = -1;
 633
 634         // Update bookkeeping
 635         giNumActiveThreads ++;
 636         giFreeTickets += Thread->NumTickets;
 637
 638         #if DEBUG_TRACE_TICKETS
 639         Log("Threads_int_AddActive: new giFreeTickets = %i", giFreeTickets);
 640         #endif
 641 }
 642
 643 /**
 644  * \brief Removes the current thread from the active queue
 645  * \warning This should ONLY be called with task switches disabled
 646  * \return Current thread pointer
 647  */
 648 tThread *Threads_RemActive(void)
 649 {
 650         tThread *ret = Proc_GetCurThread();
 651         tThread *prev = Threads_int_GetPrev(&gActiveThreads, ret);
 652         if(!prev)       return NULL;
 653         ret->Remaining = 0;
 654         ret->CurCPU = -1;
 655         prev->Next = ret->Next;
 656         giNumActiveThreads --;
 657         return ret;
 658 }
 659
 660 /**
 661  * \fn void Threads_SetFaultHandler(Uint Handler)
 662  * \brief Sets the signal handler for a signal
 663  */
 664 void Threads_SetFaultHandler(Uint Handler)
 665 {
 666         //Log_Debug("Threads", "Threads_SetFaultHandler: Handler = %p", Handler);
 667         Proc_GetCurThread()->FaultHandler = Handler;
 668 }
 669
 670 /**
 671  * \fn void Threads_Fault(int Num)
 672  * \brief Calls a fault handler
 673  */
 674 void Threads_Fault(int Num)
 675 {
 676         tThread *thread = Proc_GetCurThread();
 677
 678         Log_Log("Threads", "Threads_Fault: thread = %p", thread);
 679
 680         if(!thread)     return ;
 681
 682         Log_Log("Threads", "Threads_Fault: thread->FaultHandler = %p", thread->FaultHandler);
 683
 684         switch(thread->FaultHandler)
 685         {
 686         case 0: // Panic?
 687                 Threads_Kill(thread, -1);
 688                 HALT();
 689                 return ;
 690         case 1: // Dump Core?
 691                 Threads_Kill(thread, -1);
 692                 HALT();
 693                 return ;
 694         }
 695
 696         // Double Fault? Oh, F**k
 697         if(thread->CurFaultNum != 0) {
 698                 Threads_Kill(thread, -1);       // For now, just kill
 699                 HALT();
 700         }
 701
 702         thread->CurFaultNum = Num;
 703
 704         Proc_CallFaultHandler(thread);
 705 }
 706
 707 // --- Process Structure Access Functions ---
 708 tPID Threads_GetPID(void)
 709 {
 710         return Proc_GetCurThread()->TGID;
 711 }
 712 tTID Threads_GetTID(void)
 713 {
 714         return Proc_GetCurThread()->TID;
 715 }
 716 tUID Threads_GetUID(void)
 717 {
 718         return Proc_GetCurThread()->UID;
 719 }
 720 tGID Threads_GetGID(void)
 721 {
 722         return Proc_GetCurThread()->GID;
 723 }
 724
 725 int Threads_SetUID(Uint *Errno, tUID ID)
 726 {
 727         tThread *t = Proc_GetCurThread();
 728         if( t->UID != 0 ) {
 729                 *Errno = -EACCES;
 730                 return -1;
 731         }
 732         Log_Debug("Threads", "TID %i's UID set to %i", t->TID, ID);
 733         t->UID = ID;
 734         return 0;
 735 }
 736
 737 int Threads_SetGID(Uint *Errno, tGID ID)
 738 {
 739         tThread *t = Proc_GetCurThread();
 740         if( t->UID != 0 ) {
 741                 *Errno = -EACCES;
 742                 return -1;
 743         }
 744         Log_Debug("Threads", "TID %i's GID set to %i", t->TID, ID);
 745         t->GID = ID;
 746         return 0;
 747 }
 748
 749 /**
 750  * \fn void Threads_Dump(void)
 751  * \brief Dums a list of currently running threads
 752  */
 753 void Threads_Dump(void)
 754 {
 755         tThread *thread;
 756
 757         Log("Active Threads:");
 758         for(thread=gActiveThreads;thread;thread=thread->Next)
 759         {
 760                 Log(" %i (%i) - %s (CPU %i)",
 761                         thread->TID, thread->TGID, thread->ThreadName, thread->CurCPU);
 762                 if(thread->Status != THREAD_STAT_ACTIVE)
 763                         Log("  ERROR State (%i) != THREAD_STAT_ACTIVE (%i)", thread->Status, THREAD_STAT_ACTIVE);
 764                 Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
 765                 Log("  KStack 0x%x", thread->KernelStack);
 766         }
 767
 768         Log("All Threads:");
 769         for(thread=gAllThreads;thread;thread=thread->GlobalNext)
 770         {
 771                 Log(" %i (%i) - %s (CPU %i)",
 772                         thread->TID, thread->TGID, thread->ThreadName, thread->CurCPU);
 773                 Log("  State %i", thread->Status);
 774                 Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
 775                 Log("  KStack 0x%x", thread->KernelStack);
 776         }
 777 }
 778
 779 /**
 780  * \brief Gets the next thread to run
 781  * \param CPU   Current CPU
 782  * \param Last  The thread the CPU was running
 783  */
 784 tThread *Threads_GetNextToRun(int CPU, tThread *Last)
 785 {
 786         tThread *thread;
 787          int    ticket;
 788          int    number;
 789
 790         // Lock thread list
 791         SHORTLOCK( &glThreadListLock );
 792
 793         // Clear Delete Queue
 794         // - I should probably put this in a worker thread to avoid calling free() in the scheduler
 795         while(gDeleteThreads)
 796         {
 797                 thread = gDeleteThreads->Next;
 798                 if( IS_LOCKED(&gDeleteThreads->IsLocked) ) {    // Only free if structure is unused
 799                         // Set to dead
 800                         gDeleteThreads->Status = THREAD_STAT_DEAD;
 801                         // Free name
 802                         if( IsHeap(gDeleteThreads->ThreadName) )
 803                                 free(gDeleteThreads->ThreadName);
 804                         // Remove from global list
 805                         if( gDeleteThreads == gAllThreads )
 806                                 gAllThreads = gDeleteThreads->GlobalNext;
 807                         else
 808                                 gDeleteThreads->GlobalPrev->GlobalNext = gDeleteThreads->GlobalNext;
 809                         free( gDeleteThreads );
 810                 }
 811                 gDeleteThreads = thread;
 812         }
 813
 814         // No active threads, just take a nap
 815         if(giNumActiveThreads == 0) {
 816                 SHORTREL( &glThreadListLock );
 817                 #if DEBUG_TRACE_TICKETS
 818                 Log("No active threads");
 819                 #endif
 820                 return NULL;
 821         }
 822
 823         // Special case: 1 thread
 824         if(giNumActiveThreads == 1) {
 825                 if( gActiveThreads->CurCPU == -1 )
 826                         gActiveThreads->CurCPU = CPU;
 827                 SHORTREL( &glThreadListLock );
 828                 if( gActiveThreads->CurCPU == CPU )
 829                         return gActiveThreads;
 830                 return NULL;    // CPU has nothing to do
 831         }
 832
 833         // Allow the old thread to be scheduled again
 834         if( Last ) {
 835                 if( Last->Status == THREAD_STAT_ACTIVE ) {
 836                         giFreeTickets += Last->NumTickets;
 837                         #if DEBUG_TRACE_TICKETS
 838                         LogF(" CPU %i released %p (%i %s) into the pool (%i tickets in pool)\n",
 839                                 CPU, Last, Last->TID, Last->ThreadName, giFreeTickets);
 840                         #endif
 841                 }
 842                 #if DEBUG_TRACE_TICKETS
 843                 else
 844                         LogF(" %p (%s)->Status = %i (Released)\n", Last, Last->ThreadName, Last->Status);
 845                 #endif
 846                 Last->CurCPU = -1;
 847         }
 848
 849         #if 1
 850         number = 0;
 851         for(thread = gActiveThreads; thread; thread = thread->Next) {
 852                 if(thread->CurCPU >= 0) continue;
 853                 number += thread->NumTickets;
 854         }
 855         if(number != giFreeTickets) {
 856                 Panic("Bookkeeping fail (giFreeTickets(%i) != number(%i)) - CPU%i",
 857                         giFreeTickets, number, CPU);
 858         }
 859         #endif
 860
 861         // No free tickets (all tasks delegated to cores)
 862         if( giFreeTickets == 0 ) {
 863                 SHORTREL(&glThreadListLock);
 864                 return NULL;
 865         }
 866
 867         // Get the ticket number
 868         ticket = number = rand() % giFreeTickets;
 869
 870         // Find the next thread
 871         for(thread=gActiveThreads;thread;thread=thread->Next)
 872         {
 873                 if(thread->CurCPU >= 0) continue;
 874                 if(thread->NumTickets > number) break;
 875                 number -= thread->NumTickets;
 876         }
 877         // Error Check
 878         if(thread == NULL)
 879         {
 880                 number = 0;
 881                 for(thread=gActiveThreads;thread;thread=thread->Next) {
 882                         if(thread->CurCPU >= 0) continue;
 883                         number += thread->NumTickets;
 884                 }
 885                 Panic("Bookeeping Failed - giFreeTickets(%i) > true count (%i)",
 886                         giFreeTickets, number);
 887         }
 888         #if DEBUG_TRACE_TICKETS
 889         LogF(" CPU%i giFreeTickets = %i\n", CPU, giFreeTickets);
 890         #endif
 891
 892         // Make the new thread non-schedulable
 893         giFreeTickets -= thread->NumTickets;
 894         thread->CurCPU = CPU;
 895
 896         //Threads_Dump();
 897         #if DEBUG_TRACE_TICKETS
 898         LogF(" CPU%i giFreeTickets = %i, giving %p (%i %s CPU=%i)\n",
 899                 CPU, giFreeTickets, thread, thread->TID, thread->ThreadName, thread->CurCPU);
 900         #endif
 901
 902         SHORTREL( &glThreadListLock );
 903
 904         return thread;
 905 }
 906
 907 /**
 908  * \fn void Threads_SegFault(tVAddr Addr)
 909  * \brief Called when a Segment Fault occurs
 910  */
 911 void Threads_SegFault(tVAddr Addr)
 912 {
 913         Warning("Thread #%i committed a segfault at address %p", Proc_GetCurThread()->TID, Addr);
 914         Threads_Fault( 1 );
 915         //Threads_Exit( 0, -1 );
 916 }
 917
 918 /**
 919  * \brief Acquire a heavy mutex
 920  * \param Mutex Mutex to acquire
 921  *
 922  * This type of mutex checks if the mutex is avaliable, and acquires it
 923  * if it is. Otherwise, the current thread is added to the mutex's wait
 924  * queue and the thread suspends. When the holder of the mutex completes,
 925  * the oldest thread (top thread) on the queue is given the lock and
 926  * restarted.
 927  */
 928 void Mutex_Acquire(tMutex *Mutex)
 929 {
 930         tThread *us = Proc_GetCurThread();
 931
 932         // Get protector
 933         SHORTLOCK( &Mutex->Protector );
 934
 935         //Log("Mutex_Acquire: (%p)", Mutex);
 936
 937         // Check if the lock is already held
 938         if( Mutex->Owner ) {
 939                 SHORTLOCK( &glThreadListLock );
 940                 // - Remove from active list
 941                 Threads_RemActive();
 942                 // - Mark as sleeping
 943                 us->Status = THREAD_STAT_OFFSLEEP;
 944
 945                 // - Add to waiting
 946                 if(Mutex->LastWaiting) {
 947                         Mutex->LastWaiting->Next = us;
 948                         Mutex->LastWaiting = us;
 949                 }
 950                 else {
 951                         Mutex->Waiting = us;
 952                         Mutex->LastWaiting = us;
 953                 }
 954                 SHORTREL( &glThreadListLock );
 955                 SHORTREL( &Mutex->Protector );
 956                 while(us->Status == THREAD_STAT_OFFSLEEP)       Threads_Yield();
 957                 // We're only woken when we get the lock
 958         }
 959         // Ooh, let's take it!
 960         else {
 961                 Mutex->Owner = us;
 962                 SHORTREL( &Mutex->Protector );
 963         }
 964 }
 965
 966 /**
 967  * \brief Release a held mutex
 968  * \param Mutex Mutex to release
 969  */
 970 void Mutex_Release(tMutex *Mutex)
 971 {
 972         SHORTLOCK( &Mutex->Protector );
 973         //Log("Mutex_Release: (%p)", Mutex);
 974         if( Mutex->Waiting ) {
 975                 Mutex->Owner = Mutex->Waiting;  // Set owner
 976                 Mutex->Waiting = Mutex->Waiting->Next;  // Next!
 977                 // Wake new owner
 978                 Threads_AddActive(Mutex->Owner);
 979                 //Log("Mutex %p Woke %p", Mutex, Mutex->Owner);
 980         }
 981         else {
 982                 Mutex->Owner = NULL;
 983         }
 984         SHORTREL( &Mutex->Protector );
 985 }
 986
 987 /**
 988  * \brief Is this mutex locked?
 989  * \param Mutex Mutex pointer
 990  */
 991 int Mutex_IsLocked(tMutex *Mutex)
 992 {
 993         return Mutex->Owner != NULL;
 994 }
 995
 996 // === EXPORTS ===
 997 EXPORT(Threads_GetUID);
 998 EXPORT(Mutex_Acquire);
 999 EXPORT(Mutex_Release);
1000 EXPORT(Mutex_IsLocked);