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 };
  23 #define VM8086_PAGES_PER_INST   4
  24
  25 // === IMPORTS ===
  26  int    Proc_Clone(Uint *Err, Uint Flags);
  27
  28 // === TYPES ===
  29 struct sVM8086_InternalData
  30 {
  31         struct {
  32                 Uint32  Bitmap; // 32 sections = 128 byte blocks
  33                 tVAddr  VirtBase;
  34                 tPAddr  PhysAddr;
  35         }       AllocatedPages[VM8086_PAGES_PER_INST];
  36 };
  37
  38 // === PROTOTYPES ===
  39  int    VM8086_Install(char **Arguments);
  40 void    VM8086_GPF(tRegs *Regs);
  41 tVM8086 *VM8086_Init(void);
  42
  43 // === GLOBALS ===
  44 MODULE_DEFINE(0, 0x100, VM8086, VM8086_Install, NULL, NULL);
  45 tSpinlock       glVM8086_Process;
  46 tPID    gVM8086_WorkerPID;
  47 tTID    gVM8086_CallingThread;
  48 tVM8086 * volatile gpVM8086_State;
  49
  50 // === FUNCTIONS ===
  51 int VM8086_Install(char **Arguments)
  52 {
  53         tPID    pid;
  54
  55         // Create BIOS Call process
  56         pid = Proc_Clone(NULL, CLONE_VM);
  57         if(pid == -1)
  58         {
  59                 Log_Error("VM8086", "Unable to clone kernel into VM8086 worker");
  60                 return MODULE_ERR_MISC;
  61         }
  62         if(pid == 0)
  63         {
  64                 Uint    *stacksetup;    // Initialising Stack
  65                 Uint16  *rmstack;       // Real Mode Stack
  66                  int    i;
  67
  68                 // Set Image Name
  69                 Threads_SetName("VM8086");
  70
  71                 // Map ROM Area
  72                 for(i=0xA0;i<0x100;i++) {
  73                         MM_Map( i * 0x1000, i * 0x1000 );
  74                         //MM_SetFlags( i * 0x1000, MM_PFLAG_RO, MM_PFLAG_RO );  // Set Read Only
  75                 }
  76                 MM_Map( 0, 0 ); // IVT / BDA
  77                 for(i=0x70;i<0x80;i++) {
  78                         MM_Map( i * 0x1000, i * 0x1000 );       MM_DerefPhys( i * 0x1000 );
  79                 }
  80                 MM_Map( 0x9F000, 0x9F000 );     // Stack / EBDA
  81                 MM_Allocate( 0x100000 );        // System Stack / Stub
  82
  83                 *(Uint8*)(0x100000) = VM8086_OP_IRET;
  84                 *(Uint8*)(0x100001) = 0x07;     // POP ES
  85                 *(Uint8*)(0x100002) = 0x1F;     // POP DS
  86                 *(Uint8*)(0x100003) = 0xCB;     // RET FAR
  87
  88                 rmstack = (Uint16*)(VM8086_STACK_SEG*16 + VM8086_STACK_OFS);
  89                 *rmstack-- = 0xFFFF;    //CS
  90                 *rmstack-- = 0x0010;    //IP
  91
  92                 // Setup Stack
  93                 stacksetup = (Uint*)0x101000;
  94                 *--stacksetup = VM8086_STACK_SEG;       // GS
  95                 *--stacksetup = VM8086_STACK_SEG;       // FS
  96                 *--stacksetup = VM8086_STACK_SEG;       // DS
  97                 *--stacksetup = VM8086_STACK_SEG;       // ES
  98                 *--stacksetup = VM8086_STACK_SEG;       // SS
  99                 *--stacksetup = VM8086_STACK_OFS-2;     // SP
 100                 *--stacksetup = 0x20202;        // FLAGS
 101                 *--stacksetup = 0xFFFF; // CS
 102                 *--stacksetup = 0x10;   // IP
 103                 *--stacksetup = 0xAAAA; // AX
 104                 *--stacksetup = 0xCCCC; // CX
 105                 *--stacksetup = 0xDDDD; // DX
 106                 *--stacksetup = 0xBBBB; // BX
 107                 *--stacksetup = 0x5454; // SP
 108                 *--stacksetup = 0xB4B4; // BP
 109                 *--stacksetup = 0x5151; // SI
 110                 *--stacksetup = 0xD1D1; // DI
 111                 *--stacksetup = 0x20|3; // DS - Kernel
 112                 *--stacksetup = 0x20|3; // ES - Kernel
 113                 *--stacksetup = 0x20|3; // FS
 114                 *--stacksetup = 0x20|3; // GS
 115                 __asm__ __volatile__ (
 116                 "mov %%eax,%%esp;\n\t"  // Set stack pointer
 117                 "pop %%gs;\n\t"
 118                 "pop %%fs;\n\t"
 119                 "pop %%es;\n\t"
 120                 "pop %%ds;\n\t"
 121                 "popa;\n\t"
 122                 "iret;\n\t" : : "a" (stacksetup));
 123                 for(;;);        // Shouldn't be reached
 124         }
 125
 126         gVM8086_WorkerPID = pid;
 127         Log_Log("VM8086", "gVM8086_WorkerPID = %i", pid);
 128         Threads_Yield();        // Yield to allow the child to initialise
 129
 130         return MODULE_ERR_OK;
 131 }
 132
 133 void VM8086_GPF(tRegs *Regs)
 134 {
 135         Uint8   opcode;
 136
 137         //Log_Log("VM8086", "GPF - %04x:%04x", Regs->cs, Regs->eip);
 138
 139         if(Regs->eip == VM8086_MAGIC_IP && Regs->cs == VM8086_MAGIC_CS
 140         && Threads_GetPID() == gVM8086_WorkerPID)
 141         {
 142                 if( gpVM8086_State ) {
 143                         gpVM8086_State->AX = Regs->eax; gpVM8086_State->CX = Regs->ecx;
 144                         gpVM8086_State->DX = Regs->edx; gpVM8086_State->BX = Regs->ebx;
 145                         gpVM8086_State->BP = Regs->ebp;
 146                         gpVM8086_State->SI = Regs->esi; gpVM8086_State->DI = Regs->edi;
 147                         gpVM8086_State->DS = Regs->ds;  gpVM8086_State->ES = Regs->es;
 148                         gpVM8086_State = NULL;
 149                         Threads_WakeTID(gVM8086_CallingThread);
 150                 }
 151
 152                 //Log_Log("VM8086", "Waiting for something to do");
 153                 __asm__ __volatile__ ("sti");
 154                 // Wait for a new task
 155                 while(!gpVM8086_State) {
 156                         Threads_Sleep();
 157                         //Log_Log("VM8086", "gpVM8086_State = %p", gpVM8086_State);
 158                 }
 159
 160                 //Log_Log("VM8086", "We have a task (%p)", gpVM8086_State);
 161                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_CS;
 162                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = VM8086_MAGIC_IP;
 163                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->CS;
 164                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->IP;
 165                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->DS;
 166                 Regs->esp -= 2; *(Uint16*)( (Regs->ss<<4) + (Regs->esp&0xFFFF) ) = gpVM8086_State->ES;
 167
 168                 // Set Registers
 169                 Regs->eip = 0x11;       Regs->cs = 0xFFFF;
 170                 Regs->eax = gpVM8086_State->AX; Regs->ecx = gpVM8086_State->CX;
 171                 Regs->edx = gpVM8086_State->DX; Regs->ebx = gpVM8086_State->BX;
 172                 Regs->esi = gpVM8086_State->SI; Regs->edi = gpVM8086_State->DI;
 173                 Regs->ebp = gpVM8086_State->BP;
 174                 Regs->ds = 0x23;        Regs->es = 0x23;
 175                 Regs->fs = 0x23;        Regs->gs = 0x23;
 176                 return ;
 177         }
 178
 179         opcode = *(Uint8*)( KERNEL_BASE + (Regs->cs*16) + (Regs->eip) );
 180         Regs->eip ++;
 181         switch(opcode)
 182         {
 183         case VM8086_OP_PUSHF:   //PUSHF
 184                 Regs->esp -= 2;
 185                 *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eflags & 0xFFFF;
 186                 #if TRACE_EMU
 187                 Log_Debug("VM8086", "Emulated PUSHF");
 188                 #endif
 189                 break;
 190         case VM8086_OP_POPF:    //POPF
 191                 Regs->eflags &= 0xFFFF0002;
 192                 Regs->eflags |= *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) & 0xFFFD;        // Changing IF is not allowed
 193                 Regs->esp += 2;
 194                 #if TRACE_EMU
 195                 Log_Debug("VM8086", "Emulated POPF");
 196                 #endif
 197                 break;
 198
 199         case VM8086_OP_INT_I:   //INT imm8
 200                 {
 201                  int    id;
 202                 id = *(Uint8*)( Regs->cs*16 +(Regs->eip&0xFFFF));
 203                 Regs->eip ++;
 204
 205                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->cs;
 206                 Regs->esp -= 2; *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) ) = Regs->eip;
 207
 208                 Regs->cs = *(Uint16*)(4*id + 2);
 209                 Regs->eip = *(Uint16*)(4*id);
 210                 #if TRACE_EMU
 211                 Log_Debug("VM8086", "Emulated INT 0x%x", id);
 212                 #endif
 213                 }
 214                 break;
 215
 216         case VM8086_OP_IRET:    //IRET
 217                 Regs->eip = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 218                 Regs->cs  = *(Uint16*)( Regs->ss*16 + (Regs->esp&0xFFFF) );     Regs->esp += 2;
 219                 #if TRACE_EMU
 220                 Log_Debug("VM8086", "IRET to %04x:%04x", Regs->cs, Regs->eip);
 221                 #endif
 222                 break;
 223
 224
 225         case VM8086_OP_IN_AD:   //IN AL, DX
 226                 Regs->eax &= 0xFFFFFF00;
 227                 Regs->eax |= inb(Regs->edx&0xFFFF);
 228                 #if TRACE_EMU
 229                 Log_Debug("VM8086", "Emulated IN AL, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 230                 #endif
 231                 break;
 232         case VM8086_OP_IN_ADX:  //IN AX, DX
 233                 Regs->eax &= 0xFFFF0000;
 234                 Regs->eax |= inw(Regs->edx&0xFFFF);
 235                 #if TRACE_EMU
 236                 Log_Debug("VM8086", "Emulated IN AX, DX (Port 0x%x)\n", Regs->edx&0xFFFF);
 237                 #endif
 238                 break;
 239
 240         case 0xEE:      //OUT DX, AL
 241                 outb(Regs->edx&0xFFFF, Regs->eax&0xFF);
 242                 #if TRACE_EMU
 243                 Log_Debug("VM8086", "Emulated OUT DX, AL (*0x%04x = 0x%02x)\n", Regs->edx&0xFFFF, Regs->eax&0xFF);
 244                 #endif
 245                 break;
 246         case 0xEF:      //OUT DX, AX
 247                 outw(Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 248                 #if TRACE_EMU
 249                 Log_Debug("VM8086", "Emulated OUT DX, AX (*0x%04x = 0x%04x)\n", Regs->edx&0xFFFF, Regs->eax&0xFFFF);
 250                 #endif
 251                 break;
 252
 253         // TODO: Decide on allowing VM8086 Apps to enable/disable interrupts
 254         case 0xFA:      //CLI
 255                 break;
 256         case 0xFB:      //STI
 257                 break;
 258
 259         case 0x66:
 260                 Log_Warning("VM8086", "Code at %04x:%04x attempted to use an operand override, ignored",
 261                         Regs->cs, Regs->eip);
 262                 break;
 263
 264         default:
 265                 Log_Error("VM8086", "Error - Unknown opcode %02x caused a GPF at %04x:%04x",
 266                         opcode, Regs->cs, Regs->eip);
 267                 // Force an end to the call
 268                 Regs->cs = VM8086_MAGIC_CS;
 269                 Regs->eip = VM8086_MAGIC_IP;
 270                 break;
 271         }
 272 }
 273
 274 /**
 275  * \brief Create an instance of the VM8086 Emulator
 276  */
 277 tVM8086 *VM8086_Init(void)
 278 {
 279         tVM8086 *ret;
 280         ret = calloc( 1, sizeof(tVM8086) + sizeof(struct sVM8086_InternalData) );
 281         ret->Internal = (void*)((tVAddr)ret + sizeof(tVM8086));
 282         return ret;
 283 }
 284
 285 void VM8086_Free(tVM8086 *State)
 286 {
 287          int    i;
 288         for( i = VM8086_PAGES_PER_INST; i --; )
 289                 MM_UnmapHWPages( State->Internal->AllocatedPages[i].VirtBase, 1);
 290         free(State);
 291 }
 292
 293 void *VM8086_Allocate(tVM8086 *State, int Size, Uint16 *Segment, Uint16 *Offset)
 294 {
 295          int    i, j, base = 0;
 296          int    nBlocks, rem;
 297
 298         Size = (Size + 127) & ~127;
 299         nBlocks = Size / 128;
 300
 301         if(Size > 4096) return NULL;
 302
 303         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 304         {
 305                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  continue;
 306
 307
 308                 //Log_Debug("VM8086", "AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 309
 310                 rem = nBlocks;
 311                 base = 0;
 312                 // Scan the bitmap for a free block
 313                 for( j = 0; j < 32; j++ ) {
 314                         if( State->Internal->AllocatedPages[i].Bitmap & (1 << j) ) {
 315                                 base = j;
 316                                 rem = nBlocks;
 317                         }
 318                         else {
 319                                 rem --;
 320                                 if(rem == 0)    // Goodie, there's a gap
 321                                 {
 322                                         for( j = 0; j < nBlocks; j++ )
 323                                                 State->Internal->AllocatedPages[i].Bitmap |= 1 << (base + j);
 324                                         *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16 + base * 8;
 325                                         *Offset = 0;
 326                                         //Log_Debug("VM8086", "Allocated at #%i,%04x", i, base*128);
 327                                         return (void*)( State->Internal->AllocatedPages[i].VirtBase + base * 128 );
 328                                 }
 329                         }
 330                 }
 331         }
 332
 333         // No pages with free space?, allocate a new one
 334         for( i = 0; i < VM8086_PAGES_PER_INST; i++ )
 335         {
 336                 if( State->Internal->AllocatedPages[i].VirtBase == 0 )  break;
 337         }
 338         // Darn, we can't allocate any more
 339         if( i == VM8086_PAGES_PER_INST ) {
 340                 Log_Warning("VM8086", "Out of pages in %p", State);
 341                 return NULL;
 342         }
 343
 344         State->Internal->AllocatedPages[i].VirtBase = MM_AllocDMA(
 345                 1, 20, &State->Internal->AllocatedPages[i].PhysAddr);
 346         State->Internal->AllocatedPages[i].Bitmap = 0;
 347
 348         for( j = 0; j < nBlocks; j++ )
 349                 State->Internal->AllocatedPages[i].Bitmap |= 1 << j;
 350         //Log_Debug("VM8086", "AllocatedPages[%i].Bitmap = 0b%b", i, State->Internal->AllocatedPages[i].Bitmap);
 351         *Segment = State->Internal->AllocatedPages[i].PhysAddr / 16;
 352         *Offset = 0;
 353         return (void*) State->Internal->AllocatedPages[i].VirtBase;
 354 }
 355
 356 void *VM8086_GetPointer(tVM8086 *State, Uint16 Segment, Uint16 Offset)
 357 {
 358         return (void*)( KERNEL_BASE + Segment*16 + Offset );
 359 }
 360
 361 void VM8086_Int(tVM8086 *State, Uint8 Interrupt)
 362 {
 363         State->IP = *(Uint16*)(KERNEL_BASE+4*Interrupt);
 364         State->CS = *(Uint16*)(KERNEL_BASE+4*Interrupt+2);
 365
 366         LOCK( &glVM8086_Process );
 367
 368         gpVM8086_State = State;
 369         gVM8086_CallingThread = Threads_GetTID();
 370         Threads_WakeTID( gVM8086_WorkerPID );
 371         while( gpVM8086_State != NULL )
 372                 Threads_Sleep();
 373
 374         RELEASE( &glVM8086_Process );
 375 }