Kernel/arch/x86/mm_virt.c

   1 /*
   2  * AcessOS Microkernel Version
   3  * mm_virt.c
   4  *
   5  * Memory Map
   6  * 0xE0 - Kernel Base
   7  * 0xF0 - Kernel Stacks
   8  * 0xFD - Fractals
   9  * 0xFE - Unused
  10  * 0xFF - System Calls / Kernel's User Code
  11  */
  12 #include <common.h>
  13 #include <mm_phys.h>
  14 #include <proc.h>
  15
  16 #define KERNEL_STACKS   0xF0000000
  17 #define KERNEL_STACK_SIZE       0x00002000
  18 #define KERNEL_STACK_END        0xFD000000
  19 #define PAGE_TABLE_ADDR 0xFD000000
  20 #define PAGE_DIR_ADDR   0xFD3F4000
  21 #define PAGE_CR3_ADDR   0xFD3F4FD0
  22 #define TMP_CR3_ADDR    0xFD3F4FD4      // Part of core instead of temp
  23 #define TMP_DIR_ADDR    0xFD3F5000      // Same
  24 #define TMP_TABLE_ADDR  0xFD400000
  25 #define HW_MAP_ADDR             0xFD800000
  26 #define HW_MAP_MAX              0xFEFF0000
  27 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  28 #define TEMP_MAP_ADDR   0xFEFF0000      // Allows 16 "temp" pages
  29 #define NUM_TEMP_PAGES  16
  30
  31 #define PF_PRESENT      0x1
  32 #define PF_WRITE        0x2
  33 #define PF_USER         0x4
  34 #define PF_COW          0x200
  35 #define PF_PAGED        0x400
  36
  37 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  38
  39 // === IMPORTS ===
  40 extern Uint32   gaInitPageDir[1024];
  41 extern Uint32   gaInitPageTable[1024];
  42
  43 // === PROTOTYPES ===
  44 void    MM_PreinitVirtual();
  45 void    MM_InstallVirtual();
  46 void    MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs);
  47 void    MM_DumpTables(tVAddr Start, tVAddr End);
  48 tPAddr  MM_DuplicatePage(Uint VAddr);
  49
  50 // === GLOBALS ===
  51 tPAddr  *gaPageTable = (void*)PAGE_TABLE_ADDR;
  52 tPAddr  *gaPageDir = (void*)PAGE_DIR_ADDR;
  53 tPAddr  *gaPageCR3 = (void*)PAGE_CR3_ADDR;
  54 tPAddr  *gaTmpTable = (void*)TMP_TABLE_ADDR;
  55 tPAddr  *gaTmpDir = (void*)TMP_DIR_ADDR;
  56 tPAddr  *gTmpCR3 = (void*)TMP_CR3_ADDR;
  57  int    gilTempMappings = 0;
  58
  59 // === CODE ===
  60 /**
  61  * \fn void MM_PreinitVirtual()
  62  * \brief Maps the fractal mappings
  63  */
  64 void MM_PreinitVirtual()
  65 {
  66         gaInitPageDir[ 0 ] = 0;
  67         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((Uint)&gaInitPageDir - KERNEL_BASE) | 3;
  68 }
  69
  70 /**
  71  * \fn void MM_InstallVirtual()
  72  * \brief Sets up the constant page mappings
  73  */
  74 void MM_InstallVirtual()
  75 {
  76          int    i;
  77
  78         // --- Pre-Allocate kernel tables
  79         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
  80         {
  81                 if( gaPageDir[ i ] )    continue;
  82                 // Skip stack tables, they are process unique
  83                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACK_END >> 22) {
  84                         gaPageDir[ i ] = 0;
  85                         continue;
  86                 }
  87                 // Preallocate table
  88                 gaPageDir[ i ] = MM_AllocPhys() | 3;
  89                 INVLPG( &gaPageTable[i*1024] );
  90                 memset( &gaPageTable[i*1024], 0, 0x1000 );
  91         }
  92 }
  93
  94 /**
  95  * \fn void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
  96  * \brief Called on a page fault
  97  */
  98 void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
  99 {
 100         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 101
 102         // -- Check for COW --
 103         if( gaPageDir  [Addr>>22] & PF_PRESENT
 104          && gaPageTable[Addr>>12] & PF_PRESENT
 105          && gaPageTable[Addr>>12] & PF_COW )
 106         {
 107                 tPAddr  paddr;
 108                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 0)
 109                 {
 110                         gaPageTable[Addr>>12] &= ~PF_COW;
 111                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 112                 }
 113                 else
 114                 {
 115                         paddr = MM_DuplicatePage( Addr );
 116                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 117                         gaPageTable[Addr>>12] &= PF_USER;
 118                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 119                 }
 120                 INVLPG( Addr & ~0xFFF );
 121                 //LEAVE('-')
 122                 return;
 123         }
 124
 125         // -- Check Error Code --
 126         if(ErrorCode & 8)
 127                 Warning("Reserved Bits Trashed!");
 128         else
 129         {
 130                 Warning("%s %s %s memory%s",
 131                         (ErrorCode&4?"User":"Kernel"),
 132                         (ErrorCode&2?"write to":"read from"),
 133                         (ErrorCode&1?"bad/locked":"non-present"),
 134                         (ErrorCode&16?" (Instruction Fetch)":"")
 135                         );
 136         }
 137
 138         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 139         if( gaPageDir[Addr>>22] & PF_PRESENT )
 140                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 141
 142         MM_DumpTables(0, -1);
 143
 144         Panic("Page Fault at 0x%x\n", Regs->eip);
 145 }
 146
 147 /**
 148  * \fn void MM_DumpTables(Uint Start, Uint End)
 149  * \brief Dumps the layout of the page tables
 150  */
 151 void MM_DumpTables(tVAddr Start, tVAddr End)
 152 {
 153         tVAddr  rangeStart = 0;
 154         tPAddr  expected = 0;
 155         tVAddr  curPos;
 156         Uint    page;
 157         const tPAddr    MASK = ~0xF98;
 158
 159         Start >>= 12;   End >>= 12;
 160         for(page = Start, curPos = Start<<12;
 161                 page < End;
 162                 curPos += 0x1000, page++)
 163         {
 164                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 165                 ||  !(gaPageTable[page] & PF_PRESENT)
 166                 ||  (gaPageTable[page] & MASK) != expected)
 167                 {
 168                         if(expected) {
 169                                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 170                                         rangeStart, curPos - 1,
 171                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 172                                         (expected & ~0xFFF) - 1,
 173                                         (expected & PF_PAGED ? "p" : "-"),
 174                                         (expected & PF_COW ? "C" : "-"),
 175                                         (expected & PF_USER ? "U" : "-"),
 176                                         (expected & PF_WRITE ? "W" : "-")
 177                                         );
 178                                 expected = 0;
 179                         }
 180                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 181                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 182
 183                         expected = (gaPageTable[page] & MASK);
 184                         rangeStart = curPos;
 185                 }
 186                 if(expected)    expected += 0x1000;
 187         }
 188
 189         if(expected) {
 190                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 191                         rangeStart, curPos - 1,
 192                         gaPageTable[rangeStart>>12] & ~0xFFF,
 193                         (expected & ~0xFFF) - 1,
 194                         (expected & PF_PAGED ? "p" : "-"),
 195                         (expected & PF_COW ? "C" : "-"),
 196                         (expected & PF_USER ? "U" : "-"),
 197                         (expected & PF_WRITE ? "W" : "-")
 198                         );
 199                 expected = 0;
 200         }
 201 }
 202
 203 /**
 204  * \fn tPAddr MM_Allocate(Uint VAddr)
 205  */
 206 tPAddr MM_Allocate(Uint VAddr)
 207 {
 208         // Check if the directory is mapped
 209         if( gaPageDir[ VAddr >> 22 ] == 0 )
 210         {
 211                 // Allocate directory
 212                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 213                 // Mark as user
 214                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 215
 216                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 217                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 218         }
 219         // Check if the page is already allocated
 220         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 221                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 222                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 223         }
 224
 225         // Allocate
 226         gaPageTable[ VAddr >> 12 ] = MM_AllocPhys() | 3;
 227         // Mark as user
 228         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 229         // Invalidate Cache for address
 230         INVLPG( VAddr & ~0xFFF );
 231
 232         return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 233 }
 234
 235 /**
 236  * \fn void MM_Deallocate(Uint VAddr)
 237  */
 238 void MM_Deallocate(Uint VAddr)
 239 {
 240         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 241                 Warning("MM_Deallocate - Directory not mapped");
 242                 return;
 243         }
 244
 245         if(gaPageTable[ VAddr >> 12 ] == 0) {
 246                 Warning("MM_Deallocate - Page is not allocated");
 247                 return;
 248         }
 249
 250         // Dereference page
 251         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 252         // Clear page
 253         gaPageTable[ VAddr >> 12 ] = 0;
 254 }
 255
 256 /**
 257  * \fn tPAddr MM_GetPhysAddr(Uint Addr)
 258  * \brief Checks if the passed address is accesable
 259  */
 260 tPAddr MM_GetPhysAddr(Uint Addr)
 261 {
 262         if( !(gaPageDir[Addr >> 22] & 1) )
 263                 return 0;
 264         if( !(gaPageTable[Addr >> 12] & 1) )
 265                 return 0;
 266         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 267 }
 268
 269 /**
 270  * \fn void MM_SetCR3(Uint CR3)
 271  * \brief Sets the current process space
 272  */
 273 void MM_SetCR3(Uint CR3)
 274 {
 275         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 276 }
 277
 278 /**
 279  * \fn int MM_Map(Uint VAddr, tPAddr PAddr)
 280  * \brief Map a physical page to a virtual one
 281  */
 282 int MM_Map(Uint VAddr, tPAddr PAddr)
 283 {
 284         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 285         // Sanity check
 286         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 287                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 288                 //LEAVE('i', 0);
 289                 return 0;
 290         }
 291
 292         // Align addresses
 293         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 294
 295         // Check if the directory is mapped
 296         if( gaPageDir[ VAddr >> 22 ] == 0 )
 297         {
 298                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 299
 300                 // Mark as user
 301                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 302
 303                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 304                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 305         }
 306         // Check if the page is already allocated
 307         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 308                 Warning("MM_Map - Allocating to used address");
 309                 //LEAVE('i', 0);
 310                 return 0;
 311         }
 312
 313         // Map
 314         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 315         // Mark as user
 316         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 317
 318         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 319         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 320
 321         // Reference
 322         MM_RefPhys( PAddr );
 323
 324         //LOG("INVLPG( 0x%x )", VAddr);
 325         INVLPG( VAddr );
 326
 327         //LEAVE('i', 1);
 328         return 1;
 329 }
 330
 331 /**
 332  * \fn Uint MM_ClearUser()
 333  * \brief Clear user's address space
 334  */
 335 Uint MM_ClearUser()
 336 {
 337         Uint    i, j;
 338
 339         // Copy Directories
 340         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 341         {
 342                 // Check if directory is not allocated
 343                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 344                         gaPageDir[i] = 0;
 345                         continue;
 346                 }
 347
 348
 349                 for( j = 0; j < 1024; j ++ )
 350                 {
 351                         if( gaPageTable[i*1024+j] & 1 )
 352                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 353                         gaPageTable[i*1024+j] = 0;
 354                 }
 355
 356                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 357         }
 358
 359
 360         return *gTmpCR3;
 361 }
 362
 363 /**
 364  * \fn Uint MM_Clone()
 365  * \brief Clone the current address space
 366  */
 367 Uint MM_Clone()
 368 {
 369         Uint    i, j;
 370         Uint    kStackBase = gCurrentThread->KernelStack - KERNEL_STACK_SIZE;
 371         void    *tmp;
 372
 373         //ENTER("");
 374
 375         // Create Directory Table
 376         *gTmpCR3 = MM_AllocPhys() | 3;
 377         INVLPG( gaTmpDir );
 378         //LOG("Allocated Directory (%x)", *gTmpCR3);
 379         memsetd( gaTmpDir, 0, 1024 );
 380
 381         // Copy Tables
 382         for(i=0;i<768;i++)
 383         {
 384                 // Check if table is allocated
 385                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 386                         gaTmpDir[i] = 0;
 387                         continue;
 388                 }
 389
 390                 // Allocate new table
 391                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 392                 INVLPG( &gaTmpTable[i*1024] );
 393                 // Fill
 394                 for( j = 0; j < 1024; j ++ )
 395                 {
 396                         if( !(gaPageTable[i*1024+j] & PF_PRESENT) ) {
 397                                 gaTmpTable[i*1024+j] = 0;
 398                                 continue;
 399                         }
 400
 401                         // Refrence old page
 402                         MM_RefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 403                         // Add to new table
 404                         if(gaPageTable[i*1024+j] & PF_WRITE) {
 405                                 gaTmpTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 406                                 gaPageTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 407                         }
 408                         else
 409                                 gaTmpTable[i*1024+j] = gaPageTable[i*1024+j];
 410                 }
 411         }
 412
 413         // Map in kernel tables (and make fractal mapping)
 414         for( i = 768; i < 1024; i ++ )
 415         {
 416                 // Fractal
 417                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 418                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 419                         continue;
 420                 }
 421
 422                 if( gaPageDir[i] == 0 ) {
 423                         gaTmpDir[i] = 0;
 424                         continue;
 425                 }
 426
 427                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 428                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 429                 gaTmpDir[i] = gaPageDir[i];
 430         }
 431
 432         // Allocate kernel stack
 433         for(i = KERNEL_STACKS >> 22;
 434                 i < KERNEL_STACK_END >> 22;
 435                 i ++ )
 436         {
 437                 // Check if directory is allocated
 438                 if( (gaPageDir[i] & 1) == 0 ) {
 439                         gaTmpDir[i] = 0;
 440                         continue;
 441                 }
 442
 443                 // We don't care about other kernel stacks, just the current one
 444                 if( i != kStackBase >> 22 ) {
 445                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 446                         gaTmpDir[i] = 0;
 447                         continue;
 448                 }
 449
 450                 // Create a copy
 451                 gaTmpDir[i] = MM_AllocPhys() | 3;
 452                 INVLPG( &gaTmpTable[i*1024] );
 453                 for( j = 0; j < 1024; j ++ )
 454                 {
 455                         // Is the page allocated? If not, skip
 456                         if( !(gaPageTable[i*1024+j] & 1) ) {
 457                                 gaTmpTable[i*1024+j] = 0;
 458                                 continue;
 459                         }
 460
 461                         // We don't care about other kernel stacks
 462                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 463                                 gaTmpTable[i*1024+j] = 0;
 464                                 continue;
 465                         }
 466
 467                         // Allocate page
 468                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 469
 470                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 471
 472                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 473                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 474                         MM_FreeTemp( (Uint)tmp );
 475                 }
 476         }
 477
 478         //LEAVE('x', *gTmpCR3 & ~0xFFF);
 479         return *gTmpCR3 & ~0xFFF;
 480 }
 481
 482 /**
 483  * \fn Uint MM_NewKStack()
 484  * \brief Create a new kernel stack
 485  */
 486 Uint MM_NewKStack()
 487 {
 488         Uint    base = KERNEL_STACKS;
 489         Uint    i;
 490         for(;base<KERNEL_STACK_END;base+=KERNEL_STACK_SIZE)
 491         {
 492                 if(MM_GetPhysAddr(base) != 0)   continue;
 493                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 494                         MM_Allocate(base+i);
 495                 }
 496                 return base+KERNEL_STACK_SIZE;
 497         }
 498         Warning("MM_NewKStack - No address space left\n");
 499         return 0;
 500 }
 501
 502 /**
 503  * \fn void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 504  * \brief Sets the flags on a page
 505  */
 506 void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 507 {
 508         tPAddr  *ent;
 509         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 510         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 511
 512         ent = &gaPageTable[VAddr >> 12];
 513
 514         // Read-Only
 515         if( Mask & MM_PFLAG_RO )
 516         {
 517                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 518                 else    *ent |= PF_WRITE;
 519         }
 520
 521         // Kernel
 522         if( Mask & MM_PFLAG_KERNEL )
 523         {
 524                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 525                 else    *ent |= PF_USER;
 526         }
 527
 528         // Copy-On-Write
 529         if( Mask & MM_PFLAG_COW )
 530         {
 531                 if( Flags & MM_PFLAG_COW ) {
 532                         *ent &= ~PF_WRITE;
 533                         *ent |= PF_COW;
 534                 }
 535                 else {
 536                         *ent &= ~PF_COW;
 537                         *ent |= PF_WRITE;
 538                 }
 539         }
 540 }
 541
 542 /**
 543  * \fn tPAddr MM_DuplicatePage(Uint VAddr)
 544  * \brief Duplicates a virtual page to a physical one
 545  */
 546 tPAddr MM_DuplicatePage(Uint VAddr)
 547 {
 548         tPAddr  ret;
 549         Uint    temp;
 550          int    wasRO = 0;
 551
 552         // Check if mapped
 553         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 554         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 555
 556         // Page Align
 557         VAddr &= ~0xFFF;
 558
 559         // Allocate new page
 560         ret = MM_AllocPhys();
 561
 562         // Write-lock the page (to keep data constistent), saving its R/W state
 563         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 564         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 565         INVLPG( VAddr );
 566
 567         // Copy Data
 568         temp = MM_MapTemp(ret);
 569         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 570         MM_FreeTemp(temp);
 571
 572         // Restore Writeable status
 573         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 574         INVLPG(VAddr);
 575
 576         return ret;
 577 }
 578
 579 /**
 580  * \fn Uint MM_MapTemp(tPAddr PAddr)
 581  * \brief Create a temporary memory mapping
 582  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 583  */
 584 Uint MM_MapTemp(tPAddr PAddr)
 585 {
 586          int    i;
 587
 588         //ENTER("XPAddr", PAddr);
 589
 590         PAddr &= ~0xFFF;
 591
 592         //LOG("gilTempMappings = %i", gilTempMappings);
 593
 594         for(;;)
 595         {
 596                 LOCK( &gilTempMappings );
 597
 598                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 599                 {
 600                         // Check if page used
 601                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 602                         // Mark as used
 603                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 604                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 605                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 606                         RELEASE( &gilTempMappings );
 607                         return TEMP_MAP_ADDR + (i << 12);
 608                 }
 609                 RELEASE( &gilTempMappings );
 610                 Proc_Yield();
 611         }
 612 }
 613
 614 /**
 615  * \fn void MM_FreeTemp(Uint PAddr)
 616  * \brief Free's a temp mapping
 617  */
 618 void MM_FreeTemp(Uint VAddr)
 619 {
 620          int    i = VAddr >> 12;
 621         //ENTER("xVAddr", VAddr);
 622
 623         if(i >= (TEMP_MAP_ADDR >> 12))
 624                 gaPageTable[ i ] = 0;
 625
 626         //LEAVE('-');
 627 }
 628
 629 /**
 630  * \fn Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 631  * \brief Allocates a contigous number of pages
 632  */
 633 Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 634 {
 635          int    i, j;
 636
 637         PAddr &= ~0xFFF;
 638
 639         // Scan List
 640         for( i = 0; i < NUM_HW_PAGES; i ++ )
 641         {
 642                 // Check if addr used
 643                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 644                         continue;
 645
 646                 // Check possible region
 647                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 648                 {
 649                         // If there is an allocated page in the region we are testing, break
 650                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 651                 }
 652                 // Is it all free?
 653                 if( j == Number )
 654                 {
 655                         // Allocate
 656                         for( j = 0; j < Number; j++ ) {
 657                                 MM_RefPhys( PAddr + (j<<12) );
 658                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 659                         }
 660                         return HW_MAP_ADDR + (i<<12);
 661                 }
 662         }
 663         // If we don't find any, return NULL
 664         return 0;
 665 }
 666
 667 /**
 668  * \fn void MM_UnmapHWPage(Uint VAddr, Uint Number)
 669  * \brief Unmap a hardware page
 670  */
 671 void MM_UnmapHWPage(Uint VAddr, Uint Number)
 672 {
 673          int    i, j;
 674         // Sanity Check
 675         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 676
 677         i = VAddr >> 12;
 678
 679         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 680
 681         for( j = 0; j < Number; j++ )
 682         {
 683                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 684                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 685         }
 686
 687         RELEASE( &gilTempMappings );
 688 }
 689
 690 // --- EXPORTS ---
 691 EXPORT(MM_GetPhysAddr);
 692 EXPORT(MM_Map);
 693 //EXPORT(MM_Unmap);
 694 EXPORT(MM_MapHWPage);
 695 EXPORT(MM_UnmapHWPage);