Fixed TID0 not being on the All Threads list
[tpg/acess2.git] / Kernel / threads.c
index 99a9add..9fd052b 100644 (file)
@@ -7,7 +7,8 @@
 #include <threads.h>
 #include <errno.h>
 
-#define DEBUG_TRACE_TICKETS    0
+#define DEBUG_TRACE_TICKETS    0       // Trace ticket counts
+#define DEBUG_TRACE_STATE      0       // Trace state changes (sleep/wake)
 
 // === CONSTANTS ===
 #define        DEFAULT_QUANTUM 10
@@ -42,6 +43,7 @@ void  Threads_Yield(void);
 void   Threads_Sleep(void);
  int   Threads_Wake(tThread *Thread);
 void   Threads_AddActive(tThread *Thread);
+tThread        *Threads_RemActive(void);
  int   Threads_GetPID(void);
  int   Threads_GetTID(void);
 tUID   Threads_GetUID(void);
@@ -68,10 +70,10 @@ tThread     gThreadZero = {
 tShortSpinlock glThreadListLock;       ///\note NEVER use a heap function while locked
 // --- Current State ---
 volatile int   giNumActiveThreads = 0;
-//volatile int giTotalTickets = 0;
 volatile int   giFreeTickets = 0;
 volatile Uint  giNextTID = 1;
 // --- Thread Lists ---
+tThread        *gAllThreads = NULL;            // All allocated threads
 tThread        *gActiveThreads = NULL;         // Currently Running Threads
 tThread        *gSleepingThreads = NULL;       // Sleeping Threads
 tThread        *gDeleteThreads = NULL;         // Threads to delete
@@ -88,6 +90,7 @@ void Threads_Init(void)
        
        // Create Initial Task
        gActiveThreads = &gThreadZero;
+       gAllThreads = &gThreadZero;
        //giFreeTickets = gThreadZero.NumTickets;
        giNumActiveThreads = 1;
                
@@ -169,7 +172,7 @@ tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
        
        // Get Thread ID
        new->TID = giNextTID++;
-       new->PTID = cur->TID;
+       new->Parent = cur;
        
        // Clone Name
        new->ThreadName = strdup(cur->ThreadName);
@@ -208,6 +211,13 @@ tThread *Threads_CloneTCB(Uint *Err, Uint Flags)
                }
        }
        
+       // Maintain a global list of threads
+       SHORTLOCK( &glThreadListLock );
+       new->GlobalPrev = NULL; // Protect against bugs
+       new->GlobalNext = gAllThreads;
+       gAllThreads = new;
+       SHORTREL( &glThreadListLock );
+       
        return new;
 }
 
@@ -225,25 +235,27 @@ Uint *Threads_GetCfgPtr(int Id)
 }
 
 /**
- * \fn void Threads_WaitTID(int TID, int *status)
+ * \fn tTID Threads_WaitTID(int TID, int *status)
  * \brief Wait for a task to change state
+ * \return TID of child that changed state
  */
 int Threads_WaitTID(int TID, int *status)
 {      
        // Any Child
        if(TID == -1) {
-               
+               Log_Error("Threads", "TODO: Threads_WaitTID(TID=-1) - Any Child");
                return -1;
        }
        
        // Any peer/child thread
        if(TID == 0) {
-               
+               Log_Error("Threads", "TODO: Threads_WaitTID(TID=0) - Any Child/Sibling");
                return -1;
        }
        
        // TGID = abs(TID)
        if(TID < -1) {
+               Log_Error("Threads", "TODO: Threads_WaitTID(TID<0) - TGID");
                return -1;
        }
        
@@ -254,17 +266,25 @@ int Threads_WaitTID(int TID, int *status)
                 int    ret;
                
                if(initStatus != THREAD_STAT_ZOMBIE) {
-                       while(t->Status == initStatus) {
-                               Threads_Yield();
+                       // TODO: Handle child also being suspended if wanted
+                       while(t->Status != THREAD_STAT_ZOMBIE) {
+                               Threads_Sleep();
+                               Log_Debug("Threads", "%i waiting for %i, t->Status = %i",
+                                       Threads_GetTID(), t->TID, t->Status);
                        }
                }
                
+               Log_Debug("Threads", "%i waiting for %i, t->Status = %i",
+                       Threads_GetTID(), t->TID, t->Status);
                ret = t->RetStatus;
                switch(t->Status)
                {
                case THREAD_STAT_ZOMBIE:
+                       // Kill the thread
                        t->Status = THREAD_STAT_DEAD;
+                       // TODO: Child return value?
                        if(status)      *status = 0;
+                       // add to delete queue
                        Threads_AddToDelete( t );
                        break;
                default:
@@ -286,23 +306,16 @@ tThread *Threads_GetThread(Uint TID)
 {
        tThread *thread;
        
-       // Search Active List
-       for(thread = gActiveThreads;
-               thread;
-               thread = thread->Next)
-       {
-               if(thread->TID == TID)
-                       return thread;
-       }
-       
-       // Search Sleeping List
-       for(thread = gSleepingThreads;
+       // Search global list
+       for(thread = gAllThreads;
                thread;
-               thread = thread->Next)
+               thread = thread->GlobalNext)
        {
                if(thread->TID == TID)
                        return thread;
        }
+
+       Log("Unable to find TID %i on main list\n", TID);
        
        return NULL;
 }
@@ -398,7 +411,7 @@ void Threads_Kill(tThread *Thread, int Status)
        prev = Threads_int_GetPrev( &gActiveThreads, Thread );
        if(!prev) {
                Warning("Proc_Exit - Current thread is not on the active queue");
-               Thread->IsLocked.Lock = 0;      // We can't use SHORTREL as that starts IRQs again
+               SHORTREL( &Thread->IsLocked );
                SHORTREL( &glThreadListLock );
                return;
        }
@@ -418,9 +431,8 @@ void Threads_Kill(tThread *Thread, int Status)
        giNumActiveThreads --;
        if( Thread != Proc_GetCurThread() )
                giFreeTickets -= Thread->NumTickets;
-       //Log("Threads_Kill: giFreeTickets = %i", giFreeTickets);
        
-       // Mark thread as a zombie
+       // Save exit status
        Thread->RetStatus = Status;
        
        // Don't Zombie if we are being killed as part of a tree
@@ -430,14 +442,16 @@ void Threads_Kill(tThread *Thread, int Status)
                Threads_AddToDelete( Thread );
        } else {
                Thread->Status = THREAD_STAT_ZOMBIE;
+               // Wake parent
+               Threads_Wake( Thread->Parent );
        }
        
+       Log("Thread %i went *hurk* (%i)", Thread->TID, Thread->Status);
+       
        // Release spinlocks
-       Thread->IsLocked.Lock = 0;      // Released first so that it IS released
+       SHORTREL( &Thread->IsLocked );
        SHORTREL( &glThreadListLock );
        
-       //Log("Thread %i went *hurk*", Thread->TID);
-       
        if(Status != -1)        HALT();
 }
 
@@ -458,45 +472,32 @@ void Threads_Yield(void)
 void Threads_Sleep(void)
 {
        tThread *cur = Proc_GetCurThread();
-       tThread *thread;
        
        //Log_Log("Threads", "%i going to sleep", cur->TID);
        
        // Acquire Spinlock
        SHORTLOCK( &glThreadListLock );
        
-       // Get thread before current thread
-       thread = Threads_int_GetPrev( &gActiveThreads, cur );
-       if(!thread) {
-               Warning("Threads_Sleep - Current thread is not on the active queue");
-               Threads_Dump();
-               SHORTREL( &glThreadListLock );
-               return;
-       }
-       
        // Don't sleep if there is a message waiting
        if( cur->Messages ) {
                SHORTREL( &glThreadListLock );
                return;
        }
        
-       // Unset remaining timeslices (force a task switch on timer fire)
-       cur->Remaining = 0;
-       
-       // Remove from active list
-       thread->Next = cur->Next;
+       // Remove us from running queue
+       Threads_RemActive();
        
        // Add to Sleeping List (at the top)
        cur->Next = gSleepingThreads;
        gSleepingThreads = cur;
        
-       // Reduce the active count & ticket count
-       giNumActiveThreads --;
-       // - No need to alter giFreeTickets (we're being executed)
-       
        // Mark thread as sleeping
        cur->Status = THREAD_STAT_SLEEPING;
        
+       #if DEBUG_TRACE_STATE
+       Log("Threads_Sleep: %p (%i %s) sleeping", cur, cur->TID, cur->ThreadName);
+       #endif
+       
        // Release Spinlock
        SHORTREL( &glThreadListLock );
        
@@ -509,6 +510,7 @@ void Threads_Sleep(void)
  * \brief Wakes a sleeping/waiting thread up
  * \param Thread       Thread to wake
  * \return Boolean Failure (Returns ERRNO)
+ * \note Should be called with the scheduler lock held
  */
 int Threads_Wake(tThread *Thread)
 {
@@ -522,30 +524,35 @@ int Threads_Wake(tThread *Thread)
        case THREAD_STAT_ACTIVE:
                Log("Thread_Wake: Waking awake thread (%i)", Thread->TID);
                return -EALREADY;
+       
        case THREAD_STAT_SLEEPING:      // TODO: Comment better
-               //Log_Log("Threads", "Waking %i (%p) from sleeping (CPU=%i)",
-               //      Thread->TID, Thread, Thread->CurCPU);
-               SHORTLOCK( &glThreadListLock );
+               // Remove from sleeping queue
                prev = Threads_int_GetPrev(&gSleepingThreads, Thread);
-               prev->Next = Thread->Next;      // Remove from sleeping queue
-               Thread->Next = gActiveThreads;  // Add to active queue
+               prev->Next = Thread->Next;
+               // Add to active queue
+               Thread->Next = gActiveThreads;
                gActiveThreads = Thread;
+               // Update bookkeeping
                giNumActiveThreads ++;
-               // Thread can't be the current, so no need to check
-               Thread->CurCPU = -1;
                giFreeTickets += Thread->NumTickets;
                #if DEBUG_TRACE_TICKETS
-               Log("Threads_Wake: giFreeTickets = %i", giFreeTickets);
+               Log("Threads_Wake: new giFreeTickets = %i", giFreeTickets);
                #endif
+               Thread->CurCPU = -1;
                Thread->Status = THREAD_STAT_ACTIVE;
-               SHORTREL( &glThreadListLock );
+               #if DEBUG_TRACE_STATE
+               Log("Threads_Sleep: %p (%i %s) woken", Thread, Thread->TID, Thread->ThreadName);
+               #endif
                return -EOK;
+       
        case THREAD_STAT_WAITING:
                Warning("Thread_Wake - Waiting threads are not currently supported");
                return -ENOTIMPL;
+       
        case THREAD_STAT_DEAD:
                Warning("Thread_Wake - Attempt to wake dead thread (%i)", Thread->TID);
                return -ENOTIMPL;
+       
        default:
                Warning("Thread_Wake - Unknown process status (%i)\n", Thread->Status);
                return -EINTERNAL;
@@ -560,9 +567,13 @@ int Threads_Wake(tThread *Thread)
 int Threads_WakeTID(tTID TID)
 {
        tThread *thread = Threads_GetThread(TID);
+        int    ret;
        if(!thread)
                return -ENOENT;
-       return Threads_Wake( thread );
+       SHORTLOCK( &glThreadListLock );
+       ret = Threads_Wake( thread );
+       SHORTREL( &glThreadListLock );
+       return ret;
 }
 
 /**
@@ -572,24 +583,42 @@ int Threads_WakeTID(tTID TID)
 void Threads_AddActive(tThread *Thread)
 {
        SHORTLOCK( &glThreadListLock );
+       // Add to active list
        Thread->Next = gActiveThreads;
        gActiveThreads = Thread;
+       // Update bookkeeping
        giNumActiveThreads ++;
-       // Thread can't be the current, so no need to check
        giFreeTickets += Thread->NumTickets;
        #if DEBUG_TRACE_TICKETS
-       Log("Threads_AddActive: giFreeTickets = %i", giFreeTickets);
+       Log("Threads_AddActive: new giFreeTickets = %i", giFreeTickets);
        #endif
        SHORTREL( &glThreadListLock );
 }
 
+/**
+ * \brief Removes the current thread from the active queue
+ * \warning This should ONLY be called with task switches disabled
+ * \return Current thread pointer
+ */
+tThread *Threads_RemActive(void)
+{
+       tThread *ret = Proc_GetCurThread();
+       tThread *prev = Threads_int_GetPrev(&gActiveThreads, ret);
+       if(!prev)       return NULL;
+       ret->Remaining = 0;
+       ret->CurCPU = -1;
+       prev->Next = ret->Next;
+       giNumActiveThreads --;
+       return ret;
+}
+
 /**
  * \fn void Threads_SetFaultHandler(Uint Handler)
  * \brief Sets the signal handler for a signal
  */
 void Threads_SetFaultHandler(Uint Handler)
 {      
-       Log_Log("Threads", "Threads_SetFaultHandler: Handler = %p", Handler);
+       //Log_Debug("Threads", "Threads_SetFaultHandler: Handler = %p", Handler);
        Proc_GetCurThread()->FaultHandler = Handler;
 }
 
@@ -655,7 +684,7 @@ int Threads_SetUID(Uint *Errno, tUID ID)
                *Errno = -EACCES;
                return -1;
        }
-       Log("Threads_SetUID - Setting User ID to %i", ID);
+       Log_Debug("Threads", "TID %i's UID set to %i", t->TID, ID);
        t->UID = ID;
        return 0;
 }
@@ -667,7 +696,7 @@ int Threads_SetGID(Uint *Errno, tGID ID)
                *Errno = -EACCES;
                return -1;
        }
-       Log("Threads_SetGID - Setting Group ID to %i", ID);
+       Log_Debug("Threads", "TID %i's GID set to %i", t->TID, ID);
        t->GID = ID;
        return 0;
 }
@@ -685,14 +714,17 @@ void Threads_Dump(void)
        {
                Log(" %i (%i) - %s (CPU %i)",
                        thread->TID, thread->TGID, thread->ThreadName, thread->CurCPU);
+               Log("  State: %i", thread->Status);
                Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
                Log("  KStack 0x%x", thread->KernelStack);
        }
-       Log("Sleeping Threads:");
-       for(thread=gSleepingThreads;thread;thread=thread->Next)
+       
+       Log("All Threads:");
+       for(thread=gAllThreads;thread;thread=thread->GlobalNext)
        {
-               Log(" %i (%i) - %s",
-                       thread->TID, thread->TGID, thread->ThreadName);
+               Log(" %i (%i) - %s (CPU %i)",
+                       thread->TID, thread->TGID, thread->ThreadName, thread->CurCPU);
+               Log("  State: %i", thread->Status);
                Log("  %i Tickets, Quantum %i", thread->NumTickets, thread->Quantum);
                Log("  KStack 0x%x", thread->KernelStack);
        }
@@ -708,22 +740,26 @@ tThread *Threads_GetNextToRun(int CPU, tThread *Last)
 {
        tThread *thread;
         int    ticket;
-        int    number;
+        int    number; 
        
-       // TODO: Enable the code to tell if the current CPU has the lock or
-       //       another does.
-       
-       // Check if the thread list is locked by other code
-       // - If so, don't switch (give it a chance to complete)
-       if( IS_LOCKED(&glThreadListLock) )
-               return Last;
+       // Lock thread list
+       SHORTLOCK( &glThreadListLock );
        
        // Clear Delete Queue
        while(gDeleteThreads)
        {
                thread = gDeleteThreads->Next;
                if( IS_LOCKED(&gDeleteThreads->IsLocked) ) {    // Only free if structure is unused
-                       gDeleteThreads->Status = THREAD_STAT_NULL;
+                       // Set to dead
+                       gDeleteThreads->Status = THREAD_STAT_DEAD;
+                       // Free name
+                       if( IsHeap(gDeleteThreads->ThreadName) )
+                               free(gDeleteThreads->ThreadName);
+                       // Remove from global list
+                       if( gDeleteThreads == gAllThreads )
+                               gAllThreads = gDeleteThreads->GlobalNext;
+                       else
+                               gDeleteThreads->GlobalPrev->GlobalNext = gDeleteThreads->GlobalNext;
                        free( gDeleteThreads );
                }
                gDeleteThreads = thread;
@@ -731,19 +767,13 @@ tThread *Threads_GetNextToRun(int CPU, tThread *Last)
        
        // No active threads, just take a nap
        if(giNumActiveThreads == 0) {
+               SHORTREL( &glThreadListLock );
                #if DEBUG_TRACE_TICKETS
                Log("No active threads");
                #endif
                return NULL;
        }
        
-       // Lock thread list
-       // - HLT lock (Used because only another CPU can obtain the lock,
-       //   but it has a potentially long lock period)
-       // - Well, this CPU can obtain the lock, but that is aliveviated by
-       //   the above.
-       SHORTLOCK( &glThreadListLock );
-       
        // Special case: 1 thread
        if(giNumActiveThreads == 1) {
                if( gActiveThreads->CurCPU == -1 )
@@ -759,8 +789,8 @@ tThread *Threads_GetNextToRun(int CPU, tThread *Last)
                if( Last->Status == THREAD_STAT_ACTIVE ) {
                        giFreeTickets += Last->NumTickets;
                        #if DEBUG_TRACE_TICKETS
-                       LogF(" CPU %i released %p (%s) into the pool (%i tickets in pool)\n",
-                               CPU, Last, Last->ThreadName, Last->NumTickets);
+                       LogF(" CPU %i released %p (%i %s) into the pool (%i tickets in pool)\n",
+                               CPU, Last, Last->TID, Last->ThreadName, giFreeTickets);
                        #endif
                }
                #if DEBUG_TRACE_TICKETS
@@ -819,8 +849,8 @@ tThread *Threads_GetNextToRun(int CPU, tThread *Last)
        
        //Threads_Dump();
        #if DEBUG_TRACE_TICKETS
-       LogF(" CPU%i giFreeTickets = %i, giving %p (%s CPU=%i)\n",
-               CPU, giFreeTickets, thread, thread->ThreadName, thread->CurCPU);
+       LogF(" CPU%i giFreeTickets = %i, giving %p (%i %s CPU=%i)\n",
+               CPU, giFreeTickets, thread, thread->TID, thread->ThreadName, thread->CurCPU);
        #endif
        
        SHORTREL( &glThreadListLock );
@@ -852,7 +882,6 @@ void Threads_SegFault(tVAddr Addr)
 void Mutex_Acquire(tMutex *Mutex)
 {
        tThread *us = Proc_GetCurThread();
-       tThread *prev;
        
        // Get protector
        SHORTLOCK( &Mutex->Protector );
@@ -863,11 +892,9 @@ void Mutex_Acquire(tMutex *Mutex)
        if( Mutex->Owner ) {
                SHORTLOCK( &glThreadListLock );
                // - Remove from active list
-               us->Remaining = 0;
-               prev = Threads_int_GetPrev(&gActiveThreads, us);
-               prev->Next = us->Next;
-               giNumActiveThreads --;
-               us->Status = THREAD_STAT_SLEEPING;
+               Threads_RemActive();
+               // - Mark as sleeping
+               us->Status = THREAD_STAT_OFFSLEEP;
                
                // - Add to waiting
                if(Mutex->LastWaiting) {
@@ -880,7 +907,7 @@ void Mutex_Acquire(tMutex *Mutex)
                }
                SHORTREL( &glThreadListLock );
                SHORTREL( &Mutex->Protector );
-               while(us->Status == THREAD_STAT_SLEEPING)       HALT();
+               while(us->Status == THREAD_STAT_OFFSLEEP)       HALT();
                // We're only woken when we get the lock
        }
        // Ooh, let's take it!
@@ -904,7 +931,7 @@ void Mutex_Release(tMutex *Mutex)
                // Wake new owner
                Mutex->Owner->Status = THREAD_STAT_ACTIVE;
                Threads_AddActive(Mutex->Owner);
-               Log("Mutex %p Woke %p", Mutex, Mutex->Owner);
+               //Log("Mutex %p Woke %p", Mutex, Mutex->Owner);
        }
        else {
                Mutex->Owner = NULL;
@@ -923,3 +950,6 @@ int Mutex_IsLocked(tMutex *Mutex)
 
 // === EXPORTS ===
 EXPORT(Threads_GetUID);
+EXPORT(Mutex_Acquire);
+EXPORT(Mutex_Release);
+EXPORT(Mutex_IsLocked);

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