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