Modules/UHCI - Fixed edge case NULL dereference

[tpg/acess2.git] / Kernel / arch / x86 / vm8086.c

diff --git a/Kernel/arch/x86/vm8086.c b/Kernel/arch/x86/vm8086.c
index 879cec6..839a640 100644 (file)
--- a/Kernel/arch/x86/vm8086.c
+++ b/Kernel/arch/x86/vm8086.c
@@ -59,12 +59,15 @@ Uint32      gaVM8086_MemBitmap[VM8086_BLOCKCOUNT/32];
 int VM8086_Install(char **Arguments)
 {
        tPID    pid;    
+
+       Semaphore_Init(&gVM8086_TasksToDo, 0, 10, "VM8086", "TasksToDo");
        
        // Lock to avoid race conditions
        Mutex_Acquire( &glVM8086_Process );
        
        // Create BIOS Call process
        pid = Proc_Clone(CLONE_VM);
+       Log_Debug("VM8086", "pid = %i", pid);
        if(pid == -1)
        {
                Log_Error("VM8086", "Unable to clone kernel into VM8086 worker");
@@ -75,17 +78,16 @@ int VM8086_Install(char **Arguments)
                Uint    * volatile stacksetup;  // Initialising Stack
                Uint16  * volatile rmstack;     // Real Mode Stack
                 int    i;
-               
+
+               Log_Debug("VM8086", "Initialising worker");     
+       
                // Set Image Name
                Threads_SetName("VM8086");
 
-//             Log_Debug("VM8086", "Mapping memory");  
-       
                // Map ROM Area
                for(i=0xA0;i<0x100;i++) {
                        MM_Map( i * 0x1000, i * 0x1000 );
                }
-//             Log_Debug("VM8086", "ROM area mapped");
                MM_Map( 0, 0 ); // IVT / BDA
                // Map (but allow allocation) of 0x1000 - 0x9F000
                // - So much hack, it isn't funny
@@ -102,7 +104,6 @@ int VM8086_Install(char **Arguments)
                        gVM8086_WorkerPID = 0;
                        Threads_Exit(0, 1);
                }
-//             Log_Debug("VM8086", "Mapped low memory");
                
                *(Uint8*)(0x100000) = VM8086_OP_IRET;
                *(Uint8*)(0x100001) = 0x07;     // POP ES
@@ -148,9 +149,10 @@ int VM8086_Install(char **Arguments)
        }
        
        gVM8086_WorkerPID = pid;
-//     Log_Log("VM8086", "gVM8086_WorkerPID = %i", pid);
-       while( gpVM8086_State != NULL )
-               Threads_Yield();        // Yield to allow the child to initialise
+
+       // It's released when the GPF fires
+       Mutex_Acquire( &glVM8086_Process );
+       Mutex_Release( &glVM8086_Process );
        
        // Worker killed itself
        if( gVM8086_WorkerPID != pid ) {
@@ -164,7 +166,7 @@ void VM8086_GPF(tRegs *Regs)
 {
        Uint8   opcode;
        
-       //Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
+//     Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
        
        if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
        && Threads_GetPID() == gVM8086_WorkerPID)
@@ -174,8 +176,8 @@ void VM8086_GPF(tRegs *Regs)
                        gpVM8086_State = NULL;
                        Mutex_Release( &glVM8086_Process );     // Release lock obtained in VM8086_Install
                }
-               //Log_Log("VM8086", "gpVM8086_State = %p, gVM8086_CallingThread = %i",
-               //      gpVM8086_State, gVM8086_CallingThread);
+//             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;
@@ -192,12 +194,12 @@ void VM8086_GPF(tRegs *Regs)
                Semaphore_Wait(&gVM8086_TasksToDo, 1);
                
                //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
-               Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
-               Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
-               Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
-               Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
-               Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
-               Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
+               Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
+               Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
+               Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
+               Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
+               Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
+               Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
                
                // Set Registers
                Regs->eip = 0x11;       Regs->cs = 0xFFFF;
@@ -222,8 +224,9 @@ void VM8086_GPF(tRegs *Regs)
                #endif
                break;
        case VM8086_OP_POPF:    //POPF
-               Regs->eflags &= 0xFFFF0002;
-               Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0xFFFD;        // Changing IF is not allowed
+               // Changing IF is not allowed
+               Regs->eflags &= 0xFFFF0202;
+               Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );
                Regs->esp += 2;
                #if TRACE_EMU
                Log_Debug("VM8086", "Emulated POPF");
@@ -236,8 +239,8 @@ void VM8086_GPF(tRegs *Regs)
                id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
                Regs->eip ++;
                
-               Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
-               Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
+               Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
+               Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
                
                Regs->cs = *(Uint16*)(4*id + 2);
                Regs->eip = *(Uint16*)(4*id);