Trying to reduce the ability for a fork bomb to fault the kernel
[tpg/acess2.git] / Kernel / arch / x86 / vm8086.c
index 1f4f1f4..5253a62 100644 (file)
@@ -44,7 +44,7 @@ tVM8086       *VM8086_Init(void);
 
 // === GLOBALS ===
 MODULE_DEFINE(0, 0x100, VM8086, VM8086_Install, NULL, NULL);
-tSpinlock      glVM8086_Process;
+tMutex glVM8086_Process;
 tPID   gVM8086_WorkerPID;
 tTID   gVM8086_CallingThread;
 tVM8086        volatile * volatile gpVM8086_State = (void*)-1; // Set to -1 to avoid race conditions
@@ -55,7 +55,7 @@ int VM8086_Install(char **Arguments)
        tPID    pid;    
        
        // Lock to avoid race conditions
-       LOCK( &glVM8086_Process );
+       Mutex_Acquire( &glVM8086_Process );
        
        // Create BIOS Call process
        pid = Proc_Clone(NULL, CLONE_VM);
@@ -130,7 +130,8 @@ int VM8086_Install(char **Arguments)
        
        gVM8086_WorkerPID = pid;
        Log_Log("VM8086", "gVM8086_WorkerPID = %i", pid);
-       Threads_Yield();        // Yield to allow the child to initialise
+       while( gpVM8086_State != NULL )
+               Threads_Yield();        // Yield to allow the child to initialise
        
        return MODULE_ERR_OK;
 }
@@ -146,9 +147,11 @@ void VM8086_GPF(tRegs *Regs)
        {
                if( gpVM8086_State == (void*)-1 ) {
                        Log_Log("VM8086", "Worker thread ready and waiting");
-                       RELEASE( &glVM8086_Process );   // Release lock obtained in VM8086_Install
+                       Mutex_Release( &glVM8086_Process );     // Release lock obtained in VM8086_Install
                        gpVM8086_State = NULL;
                }
+               //Log_Log("VM8086", "gpVM8086_State = %p, gVM8086_CallingThread = %i",
+               //      gpVM8086_State, gVM8086_CallingThread);
                if( gpVM8086_State ) {
                        gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
                        gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
@@ -156,7 +159,9 @@ void VM8086_GPF(tRegs *Regs)
                        gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
                        gpVM8086_State->DS = Regs->ds;  gpVM8086_State->ES = Regs->es;
                        gpVM8086_State = NULL;
-                       Threads_WakeTID(gVM8086_CallingThread);
+                       // Ensure the caller wakes
+                       //while(Threads_WakeTID(gVM8086_CallingThread) == -EALREADY)
+                       //      Threads_Yield();
                }
                
                //Log_Log("VM8086", "Waiting for something to do");
@@ -396,13 +401,13 @@ void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
        State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
        State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
        
-       LOCK( &glVM8086_Process );
+       Mutex_Acquire( &glVM8086_Process );
        
        gpVM8086_State = State;
        gVM8086_CallingThread = Threads_GetTID();
        Threads_WakeTID( gVM8086_WorkerPID );
        while( gpVM8086_State != NULL )
-               Threads_Sleep();
+               Threads_Yield();
        
-       RELEASE( &glVM8086_Process );
+       Mutex_Release( &glVM8086_Process );
 }

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