Kernel/arch/x86/vm8086.c

   1 /*
   2  * Acess2 VM8086 Driver
   3  * - By John Hodge (thePowersGang)
   4  */
   5 #include <acess.h>
   6 #include <vm8086.h>
   7 #include <modules.h>
   8
   9 // === CONSTANTS ===
  10 #define VM8086_MAGIC_CS 0xFFFF
  11 #define VM8086_MAGIC_IP 0x0010
  12 #define VM8086_STACK_SEG        0x9F00
  13 #define VM8086_STACK_OFS        0x0AFE
  14 enum eVM8086_Opcodes
  15 {
  16         VM8086_OP_PUSHF   = 0x9C,
  17         VM8086_OP_POPF    = 0x9D,
  18         VM8086_OP_INT_I   = 0xCD,
  19         VM8086_OP_IRET    = 0xCF,
  20         VM8086_OP_IN_AD   = 0xEC,
  21         VM8086_OP_IN_ADX  = 0xED,
  22         VM8086_OP_OUT_AD  = 0xEE,
  23         VM8086_OP_OUT_ADX = 0xEF
  24 };
  25 #define VM8086_PAGES_PER_INST   4
  26
  27 // === IMPORTS ===
  28  int    Proc_Clone(Uint *Err, Uint Flags);
  29
  30 // === TYPES ===
  31 struct sVM8086_InternalData
  32 {
  33         struct {
  34                 Uint32  Bitmap; // 32 sections = 128 byte blocks
  35                 tVAddr  VirtBase;
  36                 tPAddr  PhysAddr;
  37         }       AllocatedPages[VM8086_PAGES_PER_INST];
  38 };
  39
  40 // === PROTOTYPES ===
  41  int    VM8086_Install(char **Arguments);
  42 void    VM8086_GPF(tRegs *Regs);
  43 //tVM8086       *VM8086_Init(void);
  44
  45 // === GLOBALS ===
  46 MODULE_DEFINE(0, 0x100, VM8086, VM8086_Install, NULL, NULL);
  47 tMutex  glVM8086_Process;
  48 tPID    gVM8086_WorkerPID;
  49 tTID    gVM8086_CallingThread;
  50 tVM8086 volatile * volatile gpVM8086_State = (void*)-1; // Set to -1 to avoid race conditions
  51
  52 // === FUNCTIONS ===
  53 int VM8086_Install(char **Arguments)
  54 {
  55         tPID    pid;
  56
  57         // Lock to avoid race conditions
  58         Mutex_Acquire( &glVM8086_Process );
  59
  60         // Create BIOS Call process
  61         pid = Proc_Clone(NULL, CLONE_VM);
  62         if(pid == -1)
  63         {
  64                 Log_Error("VM8086", "Unable to clone kernel into VM8086 worker");
  65                 return MODULE_ERR_MISC;
  66         }
  67         if(pid == 0)
  68         {
  69                 Uint    * volatile stacksetup;  // Initialising Stack
  70                 Uint16  * volatile rmstack;     // Real Mode Stack
  71                  int    i;
  72
  73                 // Set Image Name
  74                 Threads_SetName("VM8086");
  75
  76                 // Map ROM Area
  77                 for(i=0xA0;i<0x100;i++) {
  78                         MM_Map( i * 0x1000, i * 0x1000 );
  79                         //MM_SetFlags( i * 0x1000, MM_PFLAG_RO, MM_PFLAG_RO );  // Set Read Only
  80                 }
  81                 MM_Map( 0, 0 ); // IVT / BDA
  82                 for(i=0x10;i<0x9F;i++) {
  83                         MM_Map( i * 0x1000, i * 0x1000 );       MM_DerefPhys( i * 0x1000 );
  84                 }
  85                 MM_Map( 0x9F000, 0x9F000 );     // Stack / EBDA
  86                 // System Stack / Stub
  87                 if( MM_Allocate( 0x100000 ) == 0 ) {
  88                         Log_Error("VM8086", "Unable to allocate memory for stack/stub");
  89                         gVM8086_WorkerPID = 0;
  90                         Threads_Exit(0, 1);
  91                 }
  92
  93                 *(Uint8*)(0x100000) = VM8086_OP_IRET;
  94                 *(Uint8*)(0x100001) = 0x07;     // POP ES
  95                 *(Uint8*)(0x100002) = 0x1F;     // POP DS
  96                 *(Uint8*)(0x100003) = 0xCB;     // RET FAR
  97
  98                 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
  99                 rmstack--;      *rmstack = 0xFFFF;      //CS
 100                 rmstack--;      *rmstack = 0x0010;      //IP
 101
 102                 // Setup Stack
 103                 stacksetup = (Uint*)0x101000;
 104                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // GS
 105                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // FS
 106                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // DS
 107                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // ES
 108                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // SS
 109                 stacksetup--;   *stacksetup = VM8086_STACK_OFS-2;       // SP
 110                 stacksetup--;   *stacksetup = 0x20202;  // FLAGS
 111                 stacksetup--;   *stacksetup = 0xFFFF;   // CS
 112                 stacksetup--;   *stacksetup = 0x10;     // IP
 113                 stacksetup--;   *stacksetup = 0xAAAA;   // AX
 114                 stacksetup--;   *stacksetup = 0xCCCC;   // CX
 115                 stacksetup--;   *stacksetup = 0xDDDD;   // DX
 116                 stacksetup--;   *stacksetup = 0xBBBB;   // BX
 117                 stacksetup--;   *stacksetup = 0x5454;   // SP
 118                 stacksetup--;   *stacksetup = 0xB4B4;   // BP
 119                 stacksetup--;   *stacksetup = 0x5151;   // SI
 120                 stacksetup--;   *stacksetup = 0xD1D1;   // DI
 121                 stacksetup--;   *stacksetup = 0x20|3;   // DS - Kernel
 122                 stacksetup--;   *stacksetup = 0x20|3;   // ES - Kernel
 123                 stacksetup--;   *stacksetup = 0x20|3;   // FS
 124                 stacksetup--;   *stacksetup = 0x20|3;   // GS
 125                 __asm__ __volatile__ (
 126                 "mov %%eax,%%esp;\n\t"  // Set stack pointer
 127                 "pop %%gs;\n\t"
 128                 "pop %%fs;\n\t"
 129                 "pop %%es;\n\t"
 130                 "pop %%ds;\n\t"
 131                 "popa;\n\t"
 132                 "iret;\n\t" : : "a" (stacksetup));
 133                 for(;;);        // Shouldn't be reached
 134         }
 135
 136         gVM8086_WorkerPID = pid;
 137         Log_Log("VM8086", "gVM8086_WorkerPID = %i", pid);
 138         while( gpVM8086_State != NULL )
 139                 Threads_Yield();        // Yield to allow the child to initialise
 140
 141         // Worker killed itself
 142         if( gVM8086_WorkerPID != pid ) {
 143                 return MODULE_ERR_MISC;
 144         }
 145
 146         return MODULE_ERR_OK;
 147 }
 148
 149 void VM8086_GPF(tRegs *Regs)
 150 {
 151         Uint8   opcode;
 152
 153         //Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
 154
 155         if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
 156         && Threads_GetPID() == gVM8086_WorkerPID)
 157         {
 158                 if( gpVM8086_State == (void*)-1 ) {
 159                         Log_Log("VM8086", "Worker thread ready and waiting");
 160                         Mutex_Release( &glVM8086_Process );     // Release lock obtained in VM8086_Install
 161                         gpVM8086_State = NULL;
 162                 }
 163                 //Log_Log("VM8086", "gpVM8086_State = %p, gVM8086_CallingThread = %i",
 164                 //      gpVM8086_State, gVM8086_CallingThread);
 165                 if( gpVM8086_State ) {
 166                         gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
 167                         gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
 168                         gpVM8086_State->BP = Regs->ebp;
 169                         gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
 170                         gpVM8086_State->DS = Regs->ds;  gpVM8086_State->ES = Regs->es;
 171                         gpVM8086_State = NULL;
 172                         // Wake the caller
 173                         Threads_WakeTID(gVM8086_CallingThread);
 174                 }
 175
 176                 //Log_Log("VM8086", "Waiting for something to do");
 177                 __asm__ __volatile__ ("sti");
 178                 // Wait for a new task
 179                 while(!gpVM8086_State) {
 180                         Threads_Sleep();
 181                         //Log_Log("VM8086", "gpVM8086_State = %p", gpVM8086_State);
 182                 }
 183
 184                 //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
 185                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
 186                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
 187                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
 188                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
 189                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
 190                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
 191
 192                 // Set Registers
 193                 Regs->eip = 0x11;       Regs->cs = 0xFFFF;
 194                 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
 195                 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
 196                 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
 197                 Regs->ebp = gpVM8086_State->BP;
 198                 Regs->ds = 0x23;        Regs->es = 0x23;
 199                 Regs->fs = 0x23;        Regs->gs = 0x23;
 200                 return ;
 201         }
 202
 203         opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip) );
 204         Regs->eip ++;
 205         switch(opcode)
 206         {
 207         case VM8086_OP_PUSHF:   //PUSHF
 208                 Regs->esp -= 2;
 209                 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
 210                 #if TRACE_EMU
 211                 Log_Debug("VM8086", "Emulated PUSHF");
 212                 #endif
 213                 break;
 214         case VM8086_OP_POPF:    //POPF
 215                 Regs->eflags &= 0xFFFF0002;
 216                 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0xFFFD;        // Changing IF is not allowed
 217                 Regs->esp += 2;
 218                 #if TRACE_EMU
 219                 Log_Debug("VM8086", "Emulated POPF");
 220                 #endif
 221                 break;
 222
 223         case VM8086_OP_INT_I:   //INT imm8
 224                 {
 225                  int    id;
 226                 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
 227                 Regs->eip ++;
 228
 229                 Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
 230                 Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
 231
 232                 Regs->cs = *(Uint16*)(4*id + 2);
 233                 Regs->eip = *(Uint16*)(4*id);
 234                 #if TRACE_EMU
 235                 Log_Debug("VM8086", "Emulated INT 0x%x", id);
 236                 #endif
 237                 }
 238                 break;
 239
 240         case VM8086_OP_IRET:    //IRET
 241                 Regs->eip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 242                 Regs->cs  = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 243                 #if TRACE_EMU
 244                 Log_Debug("VM8086", "IRET to %04x:%04x", Regs->cs, Regs->eip);
 245                 #endif
 246                 break;
 247
 248
 249         case VM8086_OP_IN_AD:   //IN AL, DX
 250                 Regs->eax &= 0xFFFFFF00;
 251                 Regs->eax |= inb(Regs->edx&0xFFFF);
 252                 #if TRACE_EMU
 253                 Log_Debug("VM8086", "Emulated IN AL, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 254                 #endif
 255                 break;
 256         case VM8086_OP_IN_ADX:  //IN AX, DX
 257                 Regs->eax &= 0xFFFF0000;
 258                 Regs->eax |= inw(Regs->edx&0xFFFF);
 259                 #if TRACE_EMU
 260                 Log_Debug("VM8086", "Emulated IN AX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 261                 #endif
 262                 break;
 263
 264         case VM8086_OP_OUT_AD:  //OUT DX, AL
 265                 outb(Regs->edx&0xFFFF, Regs->eax&0xFF);
 266                 #if TRACE_EMU
 267                 Log_Debug("VM8086", "Emulated OUT DX, AL (*0x%04x = 0x%02x)\n", Regs->edx&0xFFFF, Regs->eax&0xFF);
 268                 #endif
 269                 break;
 270         case VM8086_OP_OUT_ADX: //OUT DX, AX
 271                 outw(Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 272                 #if TRACE_EMU
 273                 Log_Debug("VM8086", "Emulated OUT DX, AX (*0x%04x = 0x%04x)\n", Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 274                 #endif
 275                 break;
 276
 277         // TODO: Decide on allowing VM8086 Apps to enable/disable interrupts
 278         case 0xFA:      //CLI
 279                 break;
 280         case 0xFB:      //STI
 281                 break;
 282
 283         case 0x66:
 284                 opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip&0xFFFF));
 285                 switch( opcode )
 286                 {
 287                 case VM8086_OP_IN_ADX:  //IN AX, DX
 288                         Regs->eax = ind(Regs->edx&0xFFFF);
 289                         #if TRACE_EMU
 290                         Log_Debug("VM8086", "Emulated IN EAX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 291                         #endif
 292                         break;
 293                 case VM8086_OP_OUT_ADX: //OUT DX, AX
 294                         outd(Regs->edx&0xFFFF, Regs->eax);
 295                         #if TRACE_EMU
 296                         Log_Debug("VM8086", "Emulated OUT DX, EAX (*0x%04x = 0x%08x)\n", Regs->edx&0xFFFF, Regs->eax);
 297                         #endif
 298                         break;
 299                 default:
 300                         Log_Error("VM8086", "Error - Unknown opcode 66 %02x caused a GPF at %04x:%04x",
 301                                 Regs->cs, Regs->eip,
 302                                 opcode
 303                                 );
 304                         // Force an end to the call
 305                         Regs->cs = VM8086_MAGIC_CS;
 306                         Regs->eip = VM8086_MAGIC_IP;
 307                         break;
 308                 }
 309                 break;
 310
 311         default:
 312                 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
 313                         opcode, Regs->cs, Regs->eip);
 314                 // Force an end to the call
 315                 Regs->cs = VM8086_MAGIC_CS;
 316                 Regs->eip = VM8086_MAGIC_IP;
 317                 break;
 318         }
 319 }
 320
 321 /**
 322  * \brief Create an instance of the VM8086 Emulator
 323  */
 324 tVM8086 *VM8086_Init(void)
 325 {
 326         tVM8086 *ret;
 327         ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
 328         ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
 329         return ret;
 330 }
 331
 332 void VM8086_Free(tVM8086 *State)
 333 {
 334          int    i;
 335         for( i = VM8086_PAGES_PER_INST; i --; )
 336                 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
 337         free(State);
 338 }
 339
 340 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
 341 {
 342          int    i, j, base = 0;
 343          int    nBlocks, rem;
 344
 345         Size = (Size + 127) & ~127;
 346         nBlocks = Size / 128;
 347
 348         if(Size > 4096) return NULL;
 349
 350         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 351         {
 352                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  continue;
 353
 354
 355                 //Log_Debug("VM8086", "AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 356
 357                 rem = nBlocks;
 358                 base = 0;
 359                 // Scan the bitmap for a free block
 360                 for( j = 0; j < 32; j++ ) {
 361                         if( State->Internal->AllocatedPages[i].Bitmap & (1 << j) ) {
 362                                 base = j;
 363                                 rem = nBlocks;
 364                         }
 365                         else {
 366                                 rem --;
 367                                 if(rem == 0)    // Goodie, there's a gap
 368                                 {
 369                                         for( j = 0; j < nBlocks; j++ )
 370                                                 State->Internal->AllocatedPages[i].Bitmap |= 1 << (base + j);
 371                                         *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16 + base * 8;
 372                                         *Offset = 0;
 373                                         //Log_Debug("VM8086", "Allocated at #%i,%04x", i, base*128);
 374                                         return (void*)( State->Internal->AllocatedPages[i].VirtBase + base * 128 );
 375                                 }
 376                         }
 377                 }
 378         }
 379
 380         // No pages with free space?, allocate a new one
 381         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 382         {
 383                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  break;
 384         }
 385         // Darn, we can't allocate any more
 386         if( i == VM8086_PAGES_PER_INST ) {
 387                 Log_Warning("VM8086", "Out of pages in %p", State);
 388                 return NULL;
 389         }
 390
 391         State->Internal->AllocatedPages[i].VirtBase = MM_AllocDMA(
 392                 1, 20, &State->Internal->AllocatedPages[i].PhysAddr);
 393         State->Internal->AllocatedPages[i].Bitmap = 0;
 394
 395         for( j = 0; j < nBlocks; j++ )
 396                 State->Internal->AllocatedPages[i].Bitmap |= 1 << j;
 397         //Log_Debug("VM8086", "AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 398         *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16;
 399         *Offset = 0;
 400         return (void*) State->Internal->AllocatedPages[i].VirtBase;
 401 }
 402
 403 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
 404 {
 405         return (void*)( KERNEL_BASE + Segment*16 + Offset );
 406 }
 407
 408 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
 409 {
 410         State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
 411         State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
 412
 413         Mutex_Acquire( &glVM8086_Process );
 414
 415         gpVM8086_State = State;
 416         gVM8086_CallingThread = Threads_GetTID();
 417         Threads_WakeTID( gVM8086_WorkerPID );
 418         Threads_Sleep();
 419         while( gpVM8086_State != NULL ) Threads_Sleep();
 420
 421         Mutex_Release( &glVM8086_Process );
 422 }