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                 MM_Allocate( 0x100000 );        // System Stack / Stub
  87
  88                 *(Uint8*)(0x100000) = VM8086_OP_IRET;
  89                 *(Uint8*)(0x100001) = 0x07;     // POP ES
  90                 *(Uint8*)(0x100002) = 0x1F;     // POP DS
  91                 *(Uint8*)(0x100003) = 0xCB;     // RET FAR
  92
  93                 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
  94                 rmstack--;      *rmstack = 0xFFFF;      //CS
  95                 rmstack--;      *rmstack = 0x0010;      //IP
  96
  97                 // Setup Stack
  98                 stacksetup = (Uint*)0x101000;
  99                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // GS
 100                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // FS
 101                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // DS
 102                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // ES
 103                 stacksetup--;   *stacksetup = VM8086_STACK_SEG; // SS
 104                 stacksetup--;   *stacksetup = VM8086_STACK_OFS-2;       // SP
 105                 stacksetup--;   *stacksetup = 0x20202;  // FLAGS
 106                 stacksetup--;   *stacksetup = 0xFFFF;   // CS
 107                 stacksetup--;   *stacksetup = 0x10;     // IP
 108                 stacksetup--;   *stacksetup = 0xAAAA;   // AX
 109                 stacksetup--;   *stacksetup = 0xCCCC;   // CX
 110                 stacksetup--;   *stacksetup = 0xDDDD;   // DX
 111                 stacksetup--;   *stacksetup = 0xBBBB;   // BX
 112                 stacksetup--;   *stacksetup = 0x5454;   // SP
 113                 stacksetup--;   *stacksetup = 0xB4B4;   // BP
 114                 stacksetup--;   *stacksetup = 0x5151;   // SI
 115                 stacksetup--;   *stacksetup = 0xD1D1;   // DI
 116                 stacksetup--;   *stacksetup = 0x20|3;   // DS - Kernel
 117                 stacksetup--;   *stacksetup = 0x20|3;   // ES - Kernel
 118                 stacksetup--;   *stacksetup = 0x20|3;   // FS
 119                 stacksetup--;   *stacksetup = 0x20|3;   // GS
 120                 __asm__ __volatile__ (
 121                 "mov %%eax,%%esp;\n\t"  // Set stack pointer
 122                 "pop %%gs;\n\t"
 123                 "pop %%fs;\n\t"
 124                 "pop %%es;\n\t"
 125                 "pop %%ds;\n\t"
 126                 "popa;\n\t"
 127                 "iret;\n\t" : : "a" (stacksetup));
 128                 for(;;);        // Shouldn't be reached
 129         }
 130
 131         gVM8086_WorkerPID = pid;
 132         Log_Log("VM8086", "gVM8086_WorkerPID = %i", pid);
 133         while( gpVM8086_State != NULL )
 134                 Threads_Yield();        // Yield to allow the child to initialise
 135
 136         return MODULE_ERR_OK;
 137 }
 138
 139 void VM8086_GPF(tRegs *Regs)
 140 {
 141         Uint8   opcode;
 142
 143         //Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
 144
 145         if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
 146         && Threads_GetPID() == gVM8086_WorkerPID)
 147         {
 148                 if( gpVM8086_State == (void*)-1 ) {
 149                         Log_Log("VM8086", "Worker thread ready and waiting");
 150                         Mutex_Release( &glVM8086_Process );     // Release lock obtained in VM8086_Install
 151                         gpVM8086_State = NULL;
 152                 }
 153                 //Log_Log("VM8086", "gpVM8086_State = %p, gVM8086_CallingThread = %i",
 154                 //      gpVM8086_State, gVM8086_CallingThread);
 155                 if( gpVM8086_State ) {
 156                          int    ret;
 157                         gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
 158                         gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
 159                         gpVM8086_State->BP = Regs->ebp;
 160                         gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
 161                         gpVM8086_State->DS = Regs->ds;  gpVM8086_State->ES = Regs->es;
 162                         gpVM8086_State = NULL;
 163                         // Ensure the caller wakes
 164                         while( (ret = Threads_WakeTID(gVM8086_CallingThread)) == -EALREADY) {
 165                                 Threads_Yield();
 166                         }
 167                 }
 168
 169                 //Log_Log("VM8086", "Waiting for something to do");
 170                 __asm__ __volatile__ ("sti");
 171                 // Wait for a new task
 172                 while(!gpVM8086_State) {
 173                         Threads_Sleep();
 174                         //Log_Log("VM8086", "gpVM8086_State = %p", gpVM8086_State);
 175                 }
 176
 177                 //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
 178                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
 179                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
 180                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
 181                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
 182                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
 183                 Regs->esp -= 2; *(Uint16*volatile)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
 184
 185                 // Set Registers
 186                 Regs->eip = 0x11;       Regs->cs = 0xFFFF;
 187                 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
 188                 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
 189                 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
 190                 Regs->ebp = gpVM8086_State->BP;
 191                 Regs->ds = 0x23;        Regs->es = 0x23;
 192                 Regs->fs = 0x23;        Regs->gs = 0x23;
 193                 return ;
 194         }
 195
 196         opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip) );
 197         Regs->eip ++;
 198         switch(opcode)
 199         {
 200         case VM8086_OP_PUSHF:   //PUSHF
 201                 Regs->esp -= 2;
 202                 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
 203                 #if TRACE_EMU
 204                 Log_Debug("VM8086", "Emulated PUSHF");
 205                 #endif
 206                 break;
 207         case VM8086_OP_POPF:    //POPF
 208                 Regs->eflags &= 0xFFFF0002;
 209                 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0xFFFD;        // Changing IF is not allowed
 210                 Regs->esp += 2;
 211                 #if TRACE_EMU
 212                 Log_Debug("VM8086", "Emulated POPF");
 213                 #endif
 214                 break;
 215
 216         case VM8086_OP_INT_I:   //INT imm8
 217                 {
 218                  int    id;
 219                 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
 220                 Regs->eip ++;
 221
 222                 Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
 223                 Regs->esp -= 2; *(Uint16*volatile)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
 224
 225                 Regs->cs = *(Uint16*)(4*id + 2);
 226                 Regs->eip = *(Uint16*)(4*id);
 227                 #if TRACE_EMU
 228                 Log_Debug("VM8086", "Emulated INT 0x%x", id);
 229                 #endif
 230                 }
 231                 break;
 232
 233         case VM8086_OP_IRET:    //IRET
 234                 Regs->eip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 235                 Regs->cs  = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 236                 #if TRACE_EMU
 237                 Log_Debug("VM8086", "IRET to %04x:%04x", Regs->cs, Regs->eip);
 238                 #endif
 239                 break;
 240
 241
 242         case VM8086_OP_IN_AD:   //IN AL, DX
 243                 Regs->eax &= 0xFFFFFF00;
 244                 Regs->eax |= inb(Regs->edx&0xFFFF);
 245                 #if TRACE_EMU
 246                 Log_Debug("VM8086", "Emulated IN AL, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 247                 #endif
 248                 break;
 249         case VM8086_OP_IN_ADX:  //IN AX, DX
 250                 Regs->eax &= 0xFFFF0000;
 251                 Regs->eax |= inw(Regs->edx&0xFFFF);
 252                 #if TRACE_EMU
 253                 Log_Debug("VM8086", "Emulated IN AX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 254                 #endif
 255                 break;
 256
 257         case VM8086_OP_OUT_AD:  //OUT DX, AL
 258                 outb(Regs->edx&0xFFFF, Regs->eax&0xFF);
 259                 #if TRACE_EMU
 260                 Log_Debug("VM8086", "Emulated OUT DX, AL (*0x%04x = 0x%02x)\n", Regs->edx&0xFFFF, Regs->eax&0xFF);
 261                 #endif
 262                 break;
 263         case VM8086_OP_OUT_ADX: //OUT DX, AX
 264                 outw(Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 265                 #if TRACE_EMU
 266                 Log_Debug("VM8086", "Emulated OUT DX, AX (*0x%04x = 0x%04x)\n", Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 267                 #endif
 268                 break;
 269
 270         // TODO: Decide on allowing VM8086 Apps to enable/disable interrupts
 271         case 0xFA:      //CLI
 272                 break;
 273         case 0xFB:      //STI
 274                 break;
 275
 276         case 0x66:
 277                 opcode = *(Uint8*)( (Regs->cs*16) + (Regs->eip&0xFFFF));
 278                 switch( opcode )
 279                 {
 280                 case VM8086_OP_IN_ADX:  //IN AX, DX
 281                         Regs->eax = ind(Regs->edx&0xFFFF);
 282                         #if TRACE_EMU
 283                         Log_Debug("VM8086", "Emulated IN EAX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 284                         #endif
 285                         break;
 286                 case VM8086_OP_OUT_ADX: //OUT DX, AX
 287                         outd(Regs->edx&0xFFFF, Regs->eax);
 288                         #if TRACE_EMU
 289                         Log_Debug("VM8086", "Emulated OUT DX, EAX (*0x%04x = 0x%08x)\n", Regs->edx&0xFFFF, Regs->eax);
 290                         #endif
 291                         break;
 292                 default:
 293                         Log_Error("VM8086", "Error - Unknown opcode 66 %02x caused a GPF at %04x:%04x",
 294                                 Regs->cs, Regs->eip,
 295                                 opcode
 296                                 );
 297                         // Force an end to the call
 298                         Regs->cs = VM8086_MAGIC_CS;
 299                         Regs->eip = VM8086_MAGIC_IP;
 300                         break;
 301                 }
 302                 break;
 303
 304         default:
 305                 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
 306                         opcode, Regs->cs, Regs->eip);
 307                 // Force an end to the call
 308                 Regs->cs = VM8086_MAGIC_CS;
 309                 Regs->eip = VM8086_MAGIC_IP;
 310                 break;
 311         }
 312 }
 313
 314 /**
 315  * \brief Create an instance of the VM8086 Emulator
 316  */
 317 tVM8086 *VM8086_Init(void)
 318 {
 319         tVM8086 *ret;
 320         ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
 321         ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
 322         return ret;
 323 }
 324
 325 void VM8086_Free(tVM8086 *State)
 326 {
 327          int    i;
 328         for( i = VM8086_PAGES_PER_INST; i --; )
 329                 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
 330         free(State);
 331 }
 332
 333 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
 334 {
 335          int    i, j, base = 0;
 336          int    nBlocks, rem;
 337
 338         Size = (Size + 127) & ~127;
 339         nBlocks = Size / 128;
 340
 341         if(Size > 4096) return NULL;
 342
 343         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 344         {
 345                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  continue;
 346
 347
 348                 //Log_Debug("VM8086", "AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 349
 350                 rem = nBlocks;
 351                 base = 0;
 352                 // Scan the bitmap for a free block
 353                 for( j = 0; j < 32; j++ ) {
 354                         if( State->Internal->AllocatedPages[i].Bitmap & (1 << j) ) {
 355                                 base = j;
 356                                 rem = nBlocks;
 357                         }
 358                         else {
 359                                 rem --;
 360                                 if(rem == 0)    // Goodie, there's a gap
 361                                 {
 362                                         for( j = 0; j < nBlocks; j++ )
 363                                                 State->Internal->AllocatedPages[i].Bitmap |= 1 << (base + j);
 364                                         *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16 + base * 8;
 365                                         *Offset = 0;
 366                                         //Log_Debug("VM8086", "Allocated at #%i,%04x", i, base*128);
 367                                         return (void*)( State->Internal->AllocatedPages[i].VirtBase + base * 128 );
 368                                 }
 369                         }
 370                 }
 371         }
 372
 373         // No pages with free space?, allocate a new one
 374         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 375         {
 376                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  break;
 377         }
 378         // Darn, we can't allocate any more
 379         if( i == VM8086_PAGES_PER_INST ) {
 380                 Log_Warning("VM8086", "Out of pages in %p", State);
 381                 return NULL;
 382         }
 383
 384         State->Internal->AllocatedPages[i].VirtBase = MM_AllocDMA(
 385                 1, 20, &State->Internal->AllocatedPages[i].PhysAddr);
 386         State->Internal->AllocatedPages[i].Bitmap = 0;
 387
 388         for( j = 0; j < nBlocks; j++ )
 389                 State->Internal->AllocatedPages[i].Bitmap |= 1 << j;
 390         //Log_Debug("VM8086", "AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 391         *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16;
 392         *Offset = 0;
 393         return (void*) State->Internal->AllocatedPages[i].VirtBase;
 394 }
 395
 396 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
 397 {
 398         return (void*)( KERNEL_BASE + Segment*16 + Offset );
 399 }
 400
 401 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
 402 {
 403         State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
 404         State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
 405
 406         Mutex_Acquire( &glVM8086_Process );
 407
 408         gpVM8086_State = State;
 409         gVM8086_CallingThread = Threads_GetTID();
 410         Threads_WakeTID( gVM8086_WorkerPID );
 411         Threads_Sleep();
 412         while( gpVM8086_State != NULL ) Threads_Sleep();
 413
 414         Mutex_Release( &glVM8086_Process );
 415 }