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