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                         MM_DerefPhys( i * 0x1000 );     // Phys setup
  93                 }
  94                 MM_Map( 0x9F000, 0x9F000 );     // Stack / EBDA
  95                 // System Stack / Stub
  96                 if( MM_Allocate( 0x100000 ) == 0 ) {
  97                         Log_Error("VM8086", "Unable to allocate memory for stack/stub");
  98                         gVM8086_WorkerPID = 0;
  99                         Threads_Exit(0, 1);
 100                 }
 101
 102                 *(Uint8*)(0x100000) = VM8086_OP_IRET;
 103                 *(Uint8*)(0x100001) = 0x07;     // POP ES
 104                 *(Uint8*)(0x100002) = 0x1F;     // POP DS
 105                 *(Uint8*)(0x100003) = 0xCB;     // RET FAR
 106
 107                 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
 108                 rmstack--;      *rmstack = 0xFFFF;      //CS
 109                 rmstack--;      *rmstack = 0x0010;      //IP
 110
 111                 // Setup Stack
 112                 stacksetup = (Uint*)0x101000;
 113                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // GS
 114                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // FS
 115                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // DS
 116                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // ES
 117                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // SS
 118                 stacksetup--;   *stacksetup = VM8086_STACK_OFS-2;       // SP
 119                 stacksetup--;   *stacksetup = 0x20202;  // FLAGS
 120                 stacksetup--;   *stacksetup = 0xFFFF;   // CS
 121                 stacksetup--;   *stacksetup = 0x10;     // IP
 122                 stacksetup--;   *stacksetup = 0xAAAA;   // AX
 123                 stacksetup--;   *stacksetup = 0xCCCC;   // CX
 124                 stacksetup--;   *stacksetup = 0xDDDD;   // DX
 125                 stacksetup--;   *stacksetup = 0xBBBB;   // BX
 126                 stacksetup--;   *stacksetup = 0x5454;   // SP
 127                 stacksetup--;   *stacksetup = 0xB4B4;   // BP
 128                 stacksetup--;   *stacksetup = 0x5151;   // SI
 129                 stacksetup--;   *stacksetup = 0xD1D1;   // DI
 130                 stacksetup--;   *stacksetup = 0x20|3;   // DS - Kernel
 131                 stacksetup--;   *stacksetup = 0x20|3;   // ES - Kernel
 132                 stacksetup--;   *stacksetup = 0x20|3;   // FS
 133                 stacksetup--;   *stacksetup = 0x20|3;   // GS
 134                 __asm__ __volatile__ (
 135                 "mov %%eax,%%esp;\n\t"  // Set stack pointer
 136                 "pop %%gs;\n\t"
 137                 "pop %%fs;\n\t"
 138                 "pop %%es;\n\t"
 139                 "pop %%ds;\n\t"
 140                 "popa;\n\t"
 141                 "iret;\n\t" : : "a" (stacksetup));
 142                 for(;;);        // Shouldn't be reached
 143         }
 144
 145         gVM8086_WorkerPID = pid;
 146         Log_Log("VM8086", "gVM8086_WorkerPID = %i", pid);
 147         while( gpVM8086_State != NULL )
 148                 Threads_Yield();        // Yield to allow the child to initialise
 149
 150         // Worker killed itself
 151         if( gVM8086_WorkerPID != pid ) {
 152                 return MODULE_ERR_MISC;
 153         }
 154
 155         return MODULE_ERR_OK;
 156 }
 157
 158 void VM8086_GPF(tRegs *Regs)
 159 {
 160         Uint8   opcode;
 161
 162         //Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
 163
 164         if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
 165         && Threads_GetPID() == gVM8086_WorkerPID)
 166         {
 167                 if( gpVM8086_State == (void*)-1 ) {
 168                         Log_Log("VM8086", "Worker thread ready and waiting");
 169                         gpVM8086_State = NULL;
 170                         Mutex_Release( &glVM8086_Process );     // Release lock obtained in VM8086_Install
 171                 }
 172                 //Log_Log("VM8086", "gpVM8086_State = %p, gVM8086_CallingThread = %i",
 173                 //      gpVM8086_State, gVM8086_CallingThread);
 174                 if( gpVM8086_State ) {
 175                         gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
 176                         gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
 177                         gpVM8086_State->BP = Regs->ebp;
 178                         gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
 179                         gpVM8086_State->DS = Regs->ds;  gpVM8086_State->ES = Regs->es;
 180                         gpVM8086_State = NULL;
 181                         // Wake the caller
 182                         Threads_WakeTID(gVM8086_CallingThread);
 183                 }
 184
 185                 //Log_Log("VM8086", "Waiting for something to do");
 186                 __asm__ __volatile__ ("sti");
 187                 // Wait for a new task
 188                 while(!gpVM8086_State) {
 189                         Threads_Sleep();
 190                         //Log_Log("VM8086", "gpVM8086_State = %p", gpVM8086_State);
 191                 }
 192
 193                 //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
 194                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
 195                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
 196                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
 197                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
 198                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
 199                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
 200
 201                 // Set Registers
 202                 Regs->eip = 0x11;       Regs->cs = 0xFFFF;
 203                 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
 204                 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
 205                 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
 206                 Regs->ebp = gpVM8086_State->BP;
 207                 Regs->ds = 0x23;        Regs->es = 0x23;
 208                 Regs->fs = 0x23;        Regs->gs = 0x23;
 209                 return ;
 210         }
 211
 212         opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip) );
 213         Regs->eip ++;
 214         switch(opcode)
 215         {
 216         case VM8086_OP_PUSHF:   //PUSHF
 217                 Regs->esp -= 2;
 218                 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
 219                 #if TRACE_EMU
 220                 Log_Debug("VM8086", "Emulated PUSHF");
 221                 #endif
 222                 break;
 223         case VM8086_OP_POPF:    //POPF
 224                 Regs->eflags &= 0xFFFF0002;
 225                 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0xFFFD;        // Changing IF is not allowed
 226                 Regs->esp += 2;
 227                 #if TRACE_EMU
 228                 Log_Debug("VM8086", "Emulated POPF");
 229                 #endif
 230                 break;
 231
 232         case VM8086_OP_INT_I:   //INT imm8
 233                 {
 234                  int    id;
 235                 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
 236                 Regs->eip ++;
 237
 238                 Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
 239                 Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
 240
 241                 Regs->cs = *(Uint16*)(4*id + 2);
 242                 Regs->eip = *(Uint16*)(4*id);
 243                 #if TRACE_EMU
 244                 Log_Debug("VM8086", "Emulated INT 0x%x", id);
 245                 #endif
 246                 }
 247                 break;
 248
 249         case VM8086_OP_IRET:    //IRET
 250                 Regs->eip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 251                 Regs->cs  = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 252                 #if TRACE_EMU
 253                 Log_Debug("VM8086", "IRET to %04x:%04x", Regs->cs, Regs->eip);
 254                 #endif
 255                 break;
 256
 257
 258         case VM8086_OP_IN_AD:   //IN AL, DX
 259                 Regs->eax &= 0xFFFFFF00;
 260                 Regs->eax |= inb(Regs->edx&0xFFFF);
 261                 #if TRACE_EMU
 262                 Log_Debug("VM8086", "Emulated IN AL, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 263                 #endif
 264                 break;
 265         case VM8086_OP_IN_ADX:  //IN AX, DX
 266                 Regs->eax &= 0xFFFF0000;
 267                 Regs->eax |= inw(Regs->edx&0xFFFF);
 268                 #if TRACE_EMU
 269                 Log_Debug("VM8086", "Emulated IN AX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 270                 #endif
 271                 break;
 272
 273         case VM8086_OP_OUT_AD:  //OUT DX, AL
 274                 outb(Regs->edx&0xFFFF, Regs->eax&0xFF);
 275                 #if TRACE_EMU
 276                 Log_Debug("VM8086", "Emulated OUT DX, AL (*0x%04x = 0x%02x)\n", Regs->edx&0xFFFF, Regs->eax&0xFF);
 277                 #endif
 278                 break;
 279         case VM8086_OP_OUT_ADX: //OUT DX, AX
 280                 outw(Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 281                 #if TRACE_EMU
 282                 Log_Debug("VM8086", "Emulated OUT DX, AX (*0x%04x = 0x%04x)\n", Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 283                 #endif
 284                 break;
 285
 286         // TODO: Decide on allowing VM8086 Apps to enable/disable interrupts
 287         case 0xFA:      //CLI
 288                 break;
 289         case 0xFB:      //STI
 290                 break;
 291
 292         case 0x66:
 293                 opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip&0xFFFF));
 294                 switch( opcode )
 295                 {
 296                 case VM8086_OP_IN_ADX:  //IN AX, DX
 297                         Regs->eax = ind(Regs->edx&0xFFFF);
 298                         #if TRACE_EMU
 299                         Log_Debug("VM8086", "Emulated IN EAX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 300                         #endif
 301                         break;
 302                 case VM8086_OP_OUT_ADX: //OUT DX, AX
 303                         outd(Regs->edx&0xFFFF, Regs->eax);
 304                         #if TRACE_EMU
 305                         Log_Debug("VM8086", "Emulated OUT DX, EAX (*0x%04x = 0x%08x)\n", Regs->edx&0xFFFF, Regs->eax);
 306                         #endif
 307                         break;
 308                 default:
 309                         Log_Error("VM8086", "Error - Unknown opcode 66 %02x caused a GPF at %04x:%04x",
 310                                 Regs->cs, Regs->eip,
 311                                 opcode
 312                                 );
 313                         // Force an end to the call
 314                         Regs->cs = VM8086_MAGIC_CS;
 315                         Regs->eip = VM8086_MAGIC_IP;
 316                         break;
 317                 }
 318                 break;
 319
 320         default:
 321                 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
 322                         opcode, Regs->cs, Regs->eip);
 323                 // Force an end to the call
 324                 Regs->cs = VM8086_MAGIC_CS;
 325                 Regs->eip = VM8086_MAGIC_IP;
 326                 break;
 327         }
 328 }
 329
 330 /**
 331  * \brief Create an instance of the VM8086 Emulator
 332  */
 333 tVM8086 *VM8086_Init(void)
 334 {
 335         tVM8086 *ret;
 336         ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
 337         ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
 338         return ret;
 339 }
 340
 341 void VM8086_Free(tVM8086 *State)
 342 {
 343          int    i;
 344         for( i = VM8086_PAGES_PER_INST; i --; )
 345                 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
 346         free(State);
 347 }
 348
 349 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
 350 {
 351          int    i, j, base = 0;
 352          int    nBlocks, rem;
 353
 354         Size = (Size + 127) & ~127;
 355         nBlocks = Size / 128;
 356
 357         if(Size > 4096) return NULL;
 358
 359         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 360         {
 361                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  continue;
 362
 363
 364                 //Log_Debug("VM8086", "AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 365
 366                 rem = nBlocks;
 367                 base = 0;
 368                 // Scan the bitmap for a free block
 369                 for( j = 0; j < 32; j++ ) {
 370                         if( State->Internal->AllocatedPages[i].Bitmap & (1 << j) ) {
 371                                 base = j+1;
 372                                 rem = nBlocks;
 373                         }
 374
 375                         rem --;
 376                         if(rem == 0)    // Goodie, there's a gap
 377                         {
 378                                 for( j = 0; j < nBlocks; j++ )
 379                                         State->Internal->AllocatedPages[i].Bitmap |= 1 << (base + j);
 380                                 *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16 + base * 8;
 381                                 *Offset = 0;
 382                                 LOG("Allocated at #%i,%04x", i, base*128);
 383                                 LOG(" - %x:%x", *Segment, *Offset);
 384                                 return (void*)( State->Internal->AllocatedPages[i].VirtBase + base * 128 );
 385                         }
 386                 }
 387         }
 388
 389         // No pages with free space?, allocate a new one
 390         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 391         {
 392                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  break;
 393         }
 394         // Darn, we can't allocate any more
 395         if( i == VM8086_PAGES_PER_INST ) {
 396                 Log_Warning("VM8086", "Out of pages in %p", State);
 397                 return NULL;
 398         }
 399
 400         State->Internal->AllocatedPages[i].VirtBase = MM_AllocDMA(
 401                 1, 20, &State->Internal->AllocatedPages[i].PhysAddr);
 402         State->Internal->AllocatedPages[i].Bitmap = 0;
 403
 404         for( j = 0; j < nBlocks; j++ )
 405                 State->Internal->AllocatedPages[i].Bitmap |= 1 << j;
 406         LOG("AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 407         *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16;
 408         *Offset = 0;
 409         LOG(" - %x:%x", *Segment, *Offset);
 410         return (void*) State->Internal->AllocatedPages[i].VirtBase;
 411 }
 412
 413 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
 414 {
 415         return (void*)( KERNEL_BASE + Segment*16 + Offset );
 416 }
 417
 418 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
 419 {
 420         State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
 421         State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
 422
 423         Mutex_Acquire( &glVM8086_Process );
 424
 425         gpVM8086_State = State;
 426         gVM8086_CallingThread = Threads_GetTID();
 427         Threads_WakeTID( gVM8086_WorkerPID );
 428         Threads_Sleep();
 429         while( gpVM8086_State != NULL ) Threads_Sleep();
 430
 431         Mutex_Release( &glVM8086_Process );
 432 }