Kernel/arch/x86/vm8086.c

   1 /*
   2  * Acess2 VM8086 Driver
   3  * - By John Hodge (thePowersGang)
   4  */
   5 #define DEBUG   0
   6 #include <acess.h>
   7 #include <vm8086.h>
   8 #include <modules.h>
   9
  10 // === CONSTANTS ===
  11 #define VM8086_MAGIC_CS 0xFFFF
  12 #define VM8086_MAGIC_IP 0x0010
  13 #define VM8086_STACK_SEG        0x9F00
  14 #define VM8086_STACK_OFS        0x0AFE
  15 enum eVM8086_Opcodes
  16 {
  17         VM8086_OP_PUSHF   = 0x9C,
  18         VM8086_OP_POPF    = 0x9D,
  19         VM8086_OP_INT_I   = 0xCD,
  20         VM8086_OP_IRET    = 0xCF,
  21         VM8086_OP_IN_AD   = 0xEC,
  22         VM8086_OP_IN_ADX  = 0xED,
  23         VM8086_OP_OUT_AD  = 0xEE,
  24         VM8086_OP_OUT_ADX = 0xEF
  25 };
  26 #define VM8086_PAGES_PER_INST   4
  27
  28 #define VM8086_BLOCKSIZE        128
  29 #define VM8086_BLOCKCOUNT       ((0x9F000-0x10000)/VM8086_BLOCKSIZE)
  30
  31 // === IMPORTS ===
  32  int    Proc_Clone(Uint *Err, Uint Flags);
  33
  34 // === TYPES ===
  35 struct sVM8086_InternalData
  36 {
  37         struct {
  38                 Uint32  Bitmap; // 32 sections = 128 byte blocks
  39                 tVAddr  VirtBase;
  40                 tPAddr  PhysAddr;
  41         }       AllocatedPages[VM8086_PAGES_PER_INST];
  42 };
  43
  44 // === PROTOTYPES ===
  45  int    VM8086_Install(char **Arguments);
  46 void    VM8086_GPF(tRegs *Regs);
  47 //tVM8086       *VM8086_Init(void);
  48
  49 // === GLOBALS ===
  50 MODULE_DEFINE(0, 0x100, VM8086, VM8086_Install, NULL, NULL);
  51 tMutex  glVM8086_Process;
  52 tPID    gVM8086_WorkerPID;
  53 tTID    gVM8086_CallingThread;
  54 tVM8086 volatile * volatile gpVM8086_State = (void*)-1; // Set to -1 to avoid race conditions
  55 Uint32  gaVM8086_MemBitmap[VM8086_BLOCKCOUNT/32];
  56
  57 // === FUNCTIONS ===
  58 int VM8086_Install(char **Arguments)
  59 {
  60         tPID    pid;
  61
  62         // Lock to avoid race conditions
  63         Mutex_Acquire( &glVM8086_Process );
  64
  65         // Create BIOS Call process
  66         pid = Proc_Clone(NULL, CLONE_VM);
  67         if(pid == -1)
  68         {
  69                 Log_Error("VM8086", "Unable to clone kernel into VM8086 worker");
  70                 return MODULE_ERR_MISC;
  71         }
  72         if(pid == 0)
  73         {
  74                 Uint    * volatile stacksetup;  // Initialising Stack
  75                 Uint16  * volatile rmstack;     // Real Mode Stack
  76                  int    i;
  77
  78                 // Set Image Name
  79                 Threads_SetName("VM8086");
  80
  81                 // Map ROM Area
  82                 for(i=0xA0;i<0x100;i++) {
  83                         MM_Map( i * 0x1000, i * 0x1000 );
  84                         //MM_SetFlags( i * 0x1000, MM_PFLAG_RO, MM_PFLAG_RO );  // Set Read Only
  85                 }
  86                 MM_Map( 0, 0 ); // IVT / BDA
  87                 // Map (but allow allocation) of 0x1000 - 0x9F000
  88                 // - So much hack, it isn't funny
  89                 for(i=1;i<0x9F;i++) {
  90                         MM_Map( i * 0x1000, i * 0x1000 );
  91                         MM_DerefPhys( i * 0x1000 );     // Above
  92                         if(MM_GetRefCount(i*0x1000))
  93                                 MM_DerefPhys( i * 0x1000 );     // Phys setup
  94                 }
  95                 MM_Map( 0x9F000, 0x9F000 );     // Stack / EBDA
  96                 // System Stack / Stub
  97                 if( MM_Allocate( 0x100000 ) == 0 ) {
  98                         Log_Error("VM8086", "Unable to allocate memory for stack/stub");
  99                         gVM8086_WorkerPID = 0;
 100                         Threads_Exit(0, 1);
 101                 }
 102
 103                 *(Uint8*)(0x100000) = VM8086_OP_IRET;
 104                 *(Uint8*)(0x100001) = 0x07;     // POP ES
 105                 *(Uint8*)(0x100002) = 0x1F;     // POP DS
 106                 *(Uint8*)(0x100003) = 0xCB;     // RET FAR
 107
 108                 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
 109                 rmstack--;      *rmstack = 0xFFFF;      //CS
 110                 rmstack--;      *rmstack = 0x0010;      //IP
 111
 112                 // Setup Stack
 113                 stacksetup = (Uint*)0x101000;
 114                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // GS
 115                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // FS
 116                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // DS
 117                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // ES
 118                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // SS
 119                 stacksetup--;   *stacksetup = VM8086_STACK_OFS-2;       // SP
 120                 stacksetup--;   *stacksetup = 0x20202;  // FLAGS
 121                 stacksetup--;   *stacksetup = 0xFFFF;   // CS
 122                 stacksetup--;   *stacksetup = 0x10;     // IP
 123                 stacksetup--;   *stacksetup = 0xAAAA;   // AX
 124                 stacksetup--;   *stacksetup = 0xCCCC;   // CX
 125                 stacksetup--;   *stacksetup = 0xDDDD;   // DX
 126                 stacksetup--;   *stacksetup = 0xBBBB;   // BX
 127                 stacksetup--;   *stacksetup = 0x5454;   // SP
 128                 stacksetup--;   *stacksetup = 0xB4B4;   // BP
 129                 stacksetup--;   *stacksetup = 0x5151;   // SI
 130                 stacksetup--;   *stacksetup = 0xD1D1;   // DI
 131                 stacksetup--;   *stacksetup = 0x20|3;   // DS - Kernel
 132                 stacksetup--;   *stacksetup = 0x20|3;   // ES - Kernel
 133                 stacksetup--;   *stacksetup = 0x20|3;   // FS
 134                 stacksetup--;   *stacksetup = 0x20|3;   // GS
 135                 __asm__ __volatile__ (
 136                 "mov %%eax,%%esp;\n\t"  // Set stack pointer
 137                 "pop %%gs;\n\t"
 138                 "pop %%fs;\n\t"
 139                 "pop %%es;\n\t"
 140                 "pop %%ds;\n\t"
 141                 "popa;\n\t"
 142                 "iret;\n\t" : : "a" (stacksetup));
 143                 for(;;);        // Shouldn't be reached
 144         }
 145
 146         gVM8086_WorkerPID = pid;
 147         Log_Log("VM8086", "gVM8086_WorkerPID = %i", pid);
 148         while( gpVM8086_State != NULL )
 149                 Threads_Yield();        // Yield to allow the child to initialise
 150
 151         // Worker killed itself
 152         if( gVM8086_WorkerPID != pid ) {
 153                 return MODULE_ERR_MISC;
 154         }
 155
 156         return MODULE_ERR_OK;
 157 }
 158
 159 void VM8086_GPF(tRegs *Regs)
 160 {
 161         Uint8   opcode;
 162
 163         //Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
 164
 165         if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
 166         && Threads_GetPID() == gVM8086_WorkerPID)
 167         {
 168                 if( gpVM8086_State == (void*)-1 ) {
 169                         Log_Log("VM8086", "Worker thread ready and waiting");
 170                         gpVM8086_State = NULL;
 171                         Mutex_Release( &glVM8086_Process );     // Release lock obtained in VM8086_Install
 172                 }
 173                 //Log_Log("VM8086", "gpVM8086_State = %p, gVM8086_CallingThread = %i",
 174                 //      gpVM8086_State, gVM8086_CallingThread);
 175                 if( gpVM8086_State ) {
 176                         gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
 177                         gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
 178                         gpVM8086_State->BP = Regs->ebp;
 179                         gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
 180                         gpVM8086_State->DS = Regs->ds;  gpVM8086_State->ES = Regs->es;
 181                         gpVM8086_State = NULL;
 182                         // Wake the caller
 183                         Threads_WakeTID(gVM8086_CallingThread);
 184                 }
 185
 186                 //Log_Log("VM8086", "Waiting for something to do");
 187                 __asm__ __volatile__ ("sti");
 188                 // Wait for a new task
 189                 while(!gpVM8086_State) {
 190                         Threads_Sleep();
 191                         //Log_Log("VM8086", "gpVM8086_State = %p", gpVM8086_State);
 192                 }
 193
 194                 //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
 195                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
 196                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
 197                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
 198                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
 199                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
 200                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
 201
 202                 // Set Registers
 203                 Regs->eip = 0x11;       Regs->cs = 0xFFFF;
 204                 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
 205                 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
 206                 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
 207                 Regs->ebp = gpVM8086_State->BP;
 208                 Regs->ds = 0x23;        Regs->es = 0x23;
 209                 Regs->fs = 0x23;        Regs->gs = 0x23;
 210                 return ;
 211         }
 212
 213         opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip) );
 214         Regs->eip ++;
 215         switch(opcode)
 216         {
 217         case VM8086_OP_PUSHF:   //PUSHF
 218                 Regs->esp -= 2;
 219                 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
 220                 #if TRACE_EMU
 221                 Log_Debug("VM8086", "Emulated PUSHF");
 222                 #endif
 223                 break;
 224         case VM8086_OP_POPF:    //POPF
 225                 Regs->eflags &= 0xFFFF0002;
 226                 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0xFFFD;        // Changing IF is not allowed
 227                 Regs->esp += 2;
 228                 #if TRACE_EMU
 229                 Log_Debug("VM8086", "Emulated POPF");
 230                 #endif
 231                 break;
 232
 233         case VM8086_OP_INT_I:   //INT imm8
 234                 {
 235                  int    id;
 236                 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
 237                 Regs->eip ++;
 238
 239                 Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
 240                 Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
 241
 242                 Regs->cs = *(Uint16*)(4*id + 2);
 243                 Regs->eip = *(Uint16*)(4*id);
 244                 #if TRACE_EMU
 245                 Log_Debug("VM8086", "Emulated INT 0x%x", id);
 246                 #endif
 247                 }
 248                 break;
 249
 250         case VM8086_OP_IRET:    //IRET
 251                 Regs->eip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 252                 Regs->cs  = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 253                 #if TRACE_EMU
 254                 Log_Debug("VM8086", "IRET to %04x:%04x", Regs->cs, Regs->eip);
 255                 #endif
 256                 break;
 257
 258
 259         case VM8086_OP_IN_AD:   //IN AL, DX
 260                 Regs->eax &= 0xFFFFFF00;
 261                 Regs->eax |= inb(Regs->edx&0xFFFF);
 262                 #if TRACE_EMU
 263                 Log_Debug("VM8086", "Emulated IN AL, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 264                 #endif
 265                 break;
 266         case VM8086_OP_IN_ADX:  //IN AX, DX
 267                 Regs->eax &= 0xFFFF0000;
 268                 Regs->eax |= inw(Regs->edx&0xFFFF);
 269                 #if TRACE_EMU
 270                 Log_Debug("VM8086", "Emulated IN AX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 271                 #endif
 272                 break;
 273
 274         case VM8086_OP_OUT_AD:  //OUT DX, AL
 275                 outb(Regs->edx&0xFFFF, Regs->eax&0xFF);
 276                 #if TRACE_EMU
 277                 Log_Debug("VM8086", "Emulated OUT DX, AL (*0x%04x = 0x%02x)\n", Regs->edx&0xFFFF, Regs->eax&0xFF);
 278                 #endif
 279                 break;
 280         case VM8086_OP_OUT_ADX: //OUT DX, AX
 281                 outw(Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 282                 #if TRACE_EMU
 283                 Log_Debug("VM8086", "Emulated OUT DX, AX (*0x%04x = 0x%04x)\n", Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 284                 #endif
 285                 break;
 286
 287         // TODO: Decide on allowing VM8086 Apps to enable/disable interrupts
 288         case 0xFA:      //CLI
 289                 break;
 290         case 0xFB:      //STI
 291                 break;
 292
 293         case 0x66:
 294                 opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip&0xFFFF));
 295                 switch( opcode )
 296                 {
 297                 case VM8086_OP_IN_ADX:  //IN AX, DX
 298                         Regs->eax = ind(Regs->edx&0xFFFF);
 299                         #if TRACE_EMU
 300                         Log_Debug("VM8086", "Emulated IN EAX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 301                         #endif
 302                         break;
 303                 case VM8086_OP_OUT_ADX: //OUT DX, AX
 304                         outd(Regs->edx&0xFFFF, Regs->eax);
 305                         #if TRACE_EMU
 306                         Log_Debug("VM8086", "Emulated OUT DX, EAX (*0x%04x = 0x%08x)\n", Regs->edx&0xFFFF, Regs->eax);
 307                         #endif
 308                         break;
 309                 default:
 310                         Log_Error("VM8086", "Error - Unknown opcode 66 %02x caused a GPF at %04x:%04x",
 311                                 Regs->cs, Regs->eip,
 312                                 opcode
 313                                 );
 314                         // Force an end to the call
 315                         Regs->cs = VM8086_MAGIC_CS;
 316                         Regs->eip = VM8086_MAGIC_IP;
 317                         break;
 318                 }
 319                 break;
 320
 321         default:
 322                 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
 323                         opcode, Regs->cs, Regs->eip);
 324                 // Force an end to the call
 325                 Regs->cs = VM8086_MAGIC_CS;
 326                 Regs->eip = VM8086_MAGIC_IP;
 327                 break;
 328         }
 329 }
 330
 331 /**
 332  * \brief Create an instance of the VM8086 Emulator
 333  */
 334 tVM8086 *VM8086_Init(void)
 335 {
 336         tVM8086 *ret;
 337         ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
 338         ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
 339         return ret;
 340 }
 341
 342 void VM8086_Free(tVM8086 *State)
 343 {
 344          int    i;
 345         for( i = VM8086_PAGES_PER_INST; i --; )
 346                 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
 347         free(State);
 348 }
 349
 350 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
 351 {
 352          int    i, j, base = 0;
 353          int    nBlocks, rem;
 354
 355         Size = (Size + 127) & ~127;
 356         nBlocks = Size / 128;
 357
 358         if(Size > 4096) return NULL;
 359
 360         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 361         {
 362                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  continue;
 363
 364
 365                 //Log_Debug("VM8086", "AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 366
 367                 rem = nBlocks;
 368                 base = 0;
 369                 // Scan the bitmap for a free block
 370                 for( j = 0; j < 32; j++ ) {
 371                         if( State->Internal->AllocatedPages[i].Bitmap & (1 << j) ) {
 372                                 base = j+1;
 373                                 rem = nBlocks;
 374                         }
 375
 376                         rem --;
 377                         if(rem == 0)    // Goodie, there's a gap
 378                         {
 379                                 for( j = 0; j < nBlocks; j++ )
 380                                         State->Internal->AllocatedPages[i].Bitmap |= 1 << (base + j);
 381                                 *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16 + base * 8;
 382                                 *Offset = 0;
 383                                 LOG("Allocated at #%i,%04x", i, base*128);
 384                                 LOG(" - %x:%x", *Segment, *Offset);
 385                                 return (void*)( State->Internal->AllocatedPages[i].VirtBase + base * 128 );
 386                         }
 387                 }
 388         }
 389
 390         // No pages with free space?, allocate a new one
 391         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 392         {
 393                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  break;
 394         }
 395         // Darn, we can't allocate any more
 396         if( i == VM8086_PAGES_PER_INST ) {
 397                 Log_Warning("VM8086", "Out of pages in %p", State);
 398                 return NULL;
 399         }
 400
 401         State->Internal->AllocatedPages[i].VirtBase = MM_AllocDMA(
 402                 1, 20, &State->Internal->AllocatedPages[i].PhysAddr);
 403         State->Internal->AllocatedPages[i].Bitmap = 0;
 404
 405         for( j = 0; j < nBlocks; j++ )
 406                 State->Internal->AllocatedPages[i].Bitmap |= 1 << j;
 407         LOG("AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 408         *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16;
 409         *Offset = 0;
 410         LOG(" - %x:%x", *Segment, *Offset);
 411         return (void*) State->Internal->AllocatedPages[i].VirtBase;
 412 }
 413
 414 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
 415 {
 416         return (void*)( KERNEL_BASE + Segment*16 + Offset );
 417 }
 418
 419 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
 420 {
 421         State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
 422         State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
 423
 424         Mutex_Acquire( &glVM8086_Process );
 425
 426         gpVM8086_State = State;
 427         gVM8086_CallingThread = Threads_GetTID();
 428         Threads_WakeTID( gVM8086_WorkerPID );
 429         Threads_Sleep();
 430         while( gpVM8086_State != NULL ) Threads_Sleep();
 431
 432         Mutex_Release( &glVM8086_Process );
 433 }