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         tPAddr  paddr;
 209         // Check if the directory is mapped
 210         if( gaPageDir[ VAddr >> 22 ] == 0 )
 211         {
 212                 // Allocate directory
 213                 paddr = MM_AllocPhys();
 214                 if( paddr == 0 ) {
 215                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 216                         return 0;
 217                 }
 218                 // Map
 219                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 220                 // Mark as user
 221                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 222
 223                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 224                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 225         }
 226         // Check if the page is already allocated
 227         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 228                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 229                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 230         }
 231
 232         // Allocate
 233         paddr = MM_AllocPhys();
 234         if( paddr == 0 ) {
 235                 Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 236                 return 0;
 237         }
 238         // Map
 239         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 240         // Mark as user
 241         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 242         // Invalidate Cache for address
 243         INVLPG( VAddr & ~0xFFF );
 244
 245         return paddr;
 246 }
 247
 248 /**
 249  * \fn void MM_Deallocate(Uint VAddr)
 250  */
 251 void MM_Deallocate(Uint VAddr)
 252 {
 253         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 254                 Warning("MM_Deallocate - Directory not mapped");
 255                 return;
 256         }
 257
 258         if(gaPageTable[ VAddr >> 12 ] == 0) {
 259                 Warning("MM_Deallocate - Page is not allocated");
 260                 return;
 261         }
 262
 263         // Dereference page
 264         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 265         // Clear page
 266         gaPageTable[ VAddr >> 12 ] = 0;
 267 }
 268
 269 /**
 270  * \fn tPAddr MM_GetPhysAddr(Uint Addr)
 271  * \brief Checks if the passed address is accesable
 272  */
 273 tPAddr MM_GetPhysAddr(Uint Addr)
 274 {
 275         if( !(gaPageDir[Addr >> 22] & 1) )
 276                 return 0;
 277         if( !(gaPageTable[Addr >> 12] & 1) )
 278                 return 0;
 279         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 280 }
 281
 282 /**
 283  * \fn void MM_SetCR3(Uint CR3)
 284  * \brief Sets the current process space
 285  */
 286 void MM_SetCR3(Uint CR3)
 287 {
 288         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 289 }
 290
 291 /**
 292  * \fn int MM_Map(Uint VAddr, tPAddr PAddr)
 293  * \brief Map a physical page to a virtual one
 294  */
 295 int MM_Map(Uint VAddr, tPAddr PAddr)
 296 {
 297         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 298         // Sanity check
 299         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 300                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 301                 //LEAVE('i', 0);
 302                 return 0;
 303         }
 304
 305         // Align addresses
 306         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 307
 308         // Check if the directory is mapped
 309         if( gaPageDir[ VAddr >> 22 ] == 0 )
 310         {
 311                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 312
 313                 // Mark as user
 314                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 315
 316                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 317                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 318         }
 319         // Check if the page is already allocated
 320         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 321                 Warning("MM_Map - Allocating to used address");
 322                 //LEAVE('i', 0);
 323                 return 0;
 324         }
 325
 326         // Map
 327         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 328         // Mark as user
 329         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 330
 331         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 332         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 333
 334         // Reference
 335         MM_RefPhys( PAddr );
 336
 337         //LOG("INVLPG( 0x%x )", VAddr);
 338         INVLPG( VAddr );
 339
 340         //LEAVE('i', 1);
 341         return 1;
 342 }
 343
 344 /**
 345  * \fn Uint MM_ClearUser()
 346  * \brief Clear user's address space
 347  */
 348 Uint MM_ClearUser()
 349 {
 350         Uint    i, j;
 351
 352         // Copy Directories
 353         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 354         {
 355                 // Check if directory is not allocated
 356                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 357                         gaPageDir[i] = 0;
 358                         continue;
 359                 }
 360
 361
 362                 for( j = 0; j < 1024; j ++ )
 363                 {
 364                         if( gaPageTable[i*1024+j] & 1 )
 365                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 366                         gaPageTable[i*1024+j] = 0;
 367                 }
 368
 369                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 370         }
 371
 372
 373         return *gTmpCR3;
 374 }
 375
 376 /**
 377  * \fn Uint MM_Clone()
 378  * \brief Clone the current address space
 379  */
 380 Uint MM_Clone()
 381 {
 382         Uint    i, j;
 383         Uint    kStackBase = gCurrentThread->KernelStack - KERNEL_STACK_SIZE;
 384         void    *tmp;
 385
 386         //ENTER("");
 387
 388         // Create Directory Table
 389         *gTmpCR3 = MM_AllocPhys() | 3;
 390         INVLPG( gaTmpDir );
 391         //LOG("Allocated Directory (%x)", *gTmpCR3);
 392         memsetd( gaTmpDir, 0, 1024 );
 393
 394         // Copy Tables
 395         for(i=0;i<768;i++)
 396         {
 397                 // Check if table is allocated
 398                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 399                         gaTmpDir[i] = 0;
 400                         continue;
 401                 }
 402
 403                 // Allocate new table
 404                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 405                 INVLPG( &gaTmpTable[i*1024] );
 406                 // Fill
 407                 for( j = 0; j < 1024; j ++ )
 408                 {
 409                         if( !(gaPageTable[i*1024+j] & PF_PRESENT) ) {
 410                                 gaTmpTable[i*1024+j] = 0;
 411                                 continue;
 412                         }
 413
 414                         // Refrence old page
 415                         MM_RefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 416                         // Add to new table
 417                         if(gaPageTable[i*1024+j] & PF_WRITE) {
 418                                 gaTmpTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 419                                 gaPageTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 420                         }
 421                         else
 422                                 gaTmpTable[i*1024+j] = gaPageTable[i*1024+j];
 423                 }
 424         }
 425
 426         // Map in kernel tables (and make fractal mapping)
 427         for( i = 768; i < 1024; i ++ )
 428         {
 429                 // Fractal
 430                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 431                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 432                         continue;
 433                 }
 434
 435                 if( gaPageDir[i] == 0 ) {
 436                         gaTmpDir[i] = 0;
 437                         continue;
 438                 }
 439
 440                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 441                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 442                 gaTmpDir[i] = gaPageDir[i];
 443         }
 444
 445         // Allocate kernel stack
 446         for(i = KERNEL_STACKS >> 22;
 447                 i < KERNEL_STACK_END >> 22;
 448                 i ++ )
 449         {
 450                 // Check if directory is allocated
 451                 if( (gaPageDir[i] & 1) == 0 ) {
 452                         gaTmpDir[i] = 0;
 453                         continue;
 454                 }
 455
 456                 // We don't care about other kernel stacks, just the current one
 457                 if( i != kStackBase >> 22 ) {
 458                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 459                         gaTmpDir[i] = 0;
 460                         continue;
 461                 }
 462
 463                 // Create a copy
 464                 gaTmpDir[i] = MM_AllocPhys() | 3;
 465                 INVLPG( &gaTmpTable[i*1024] );
 466                 for( j = 0; j < 1024; j ++ )
 467                 {
 468                         // Is the page allocated? If not, skip
 469                         if( !(gaPageTable[i*1024+j] & 1) ) {
 470                                 gaTmpTable[i*1024+j] = 0;
 471                                 continue;
 472                         }
 473
 474                         // We don't care about other kernel stacks
 475                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 476                                 gaTmpTable[i*1024+j] = 0;
 477                                 continue;
 478                         }
 479
 480                         // Allocate page
 481                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 482
 483                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 484
 485                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 486                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 487                         MM_FreeTemp( (Uint)tmp );
 488                 }
 489         }
 490
 491         //LEAVE('x', *gTmpCR3 & ~0xFFF);
 492         return *gTmpCR3 & ~0xFFF;
 493 }
 494
 495 /**
 496  * \fn Uint MM_NewKStack()
 497  * \brief Create a new kernel stack
 498  */
 499 Uint MM_NewKStack()
 500 {
 501         Uint    base = KERNEL_STACKS;
 502         Uint    i;
 503         for(;base<KERNEL_STACK_END;base+=KERNEL_STACK_SIZE)
 504         {
 505                 if(MM_GetPhysAddr(base) != 0)   continue;
 506                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 507                         MM_Allocate(base+i);
 508                 }
 509                 return base+KERNEL_STACK_SIZE;
 510         }
 511         Warning("MM_NewKStack - No address space left\n");
 512         return 0;
 513 }
 514
 515 /**
 516  * \fn void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 517  * \brief Sets the flags on a page
 518  */
 519 void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 520 {
 521         tPAddr  *ent;
 522         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 523         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 524
 525         ent = &gaPageTable[VAddr >> 12];
 526
 527         // Read-Only
 528         if( Mask & MM_PFLAG_RO )
 529         {
 530                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 531                 else    *ent |= PF_WRITE;
 532         }
 533
 534         // Kernel
 535         if( Mask & MM_PFLAG_KERNEL )
 536         {
 537                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 538                 else    *ent |= PF_USER;
 539         }
 540
 541         // Copy-On-Write
 542         if( Mask & MM_PFLAG_COW )
 543         {
 544                 if( Flags & MM_PFLAG_COW ) {
 545                         *ent &= ~PF_WRITE;
 546                         *ent |= PF_COW;
 547                 }
 548                 else {
 549                         *ent &= ~PF_COW;
 550                         *ent |= PF_WRITE;
 551                 }
 552         }
 553 }
 554
 555 /**
 556  * \fn tPAddr MM_DuplicatePage(Uint VAddr)
 557  * \brief Duplicates a virtual page to a physical one
 558  */
 559 tPAddr MM_DuplicatePage(Uint VAddr)
 560 {
 561         tPAddr  ret;
 562         Uint    temp;
 563          int    wasRO = 0;
 564
 565         // Check if mapped
 566         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 567         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 568
 569         // Page Align
 570         VAddr &= ~0xFFF;
 571
 572         // Allocate new page
 573         ret = MM_AllocPhys();
 574
 575         // Write-lock the page (to keep data constistent), saving its R/W state
 576         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 577         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 578         INVLPG( VAddr );
 579
 580         // Copy Data
 581         temp = MM_MapTemp(ret);
 582         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 583         MM_FreeTemp(temp);
 584
 585         // Restore Writeable status
 586         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 587         INVLPG(VAddr);
 588
 589         return ret;
 590 }
 591
 592 /**
 593  * \fn Uint MM_MapTemp(tPAddr PAddr)
 594  * \brief Create a temporary memory mapping
 595  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 596  */
 597 Uint MM_MapTemp(tPAddr PAddr)
 598 {
 599          int    i;
 600
 601         //ENTER("XPAddr", PAddr);
 602
 603         PAddr &= ~0xFFF;
 604
 605         //LOG("gilTempMappings = %i", gilTempMappings);
 606
 607         for(;;)
 608         {
 609                 LOCK( &gilTempMappings );
 610
 611                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 612                 {
 613                         // Check if page used
 614                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 615                         // Mark as used
 616                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 617                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 618                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 619                         RELEASE( &gilTempMappings );
 620                         return TEMP_MAP_ADDR + (i << 12);
 621                 }
 622                 RELEASE( &gilTempMappings );
 623                 Proc_Yield();
 624         }
 625 }
 626
 627 /**
 628  * \fn void MM_FreeTemp(Uint PAddr)
 629  * \brief Free's a temp mapping
 630  */
 631 void MM_FreeTemp(Uint VAddr)
 632 {
 633          int    i = VAddr >> 12;
 634         //ENTER("xVAddr", VAddr);
 635
 636         if(i >= (TEMP_MAP_ADDR >> 12))
 637                 gaPageTable[ i ] = 0;
 638
 639         //LEAVE('-');
 640 }
 641
 642 /**
 643  * \fn Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 644  * \brief Allocates a contigous number of pages
 645  */
 646 Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 647 {
 648          int    i, j;
 649
 650         PAddr &= ~0xFFF;
 651
 652         // Scan List
 653         for( i = 0; i < NUM_HW_PAGES; i ++ )
 654         {
 655                 // Check if addr used
 656                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 657                         continue;
 658
 659                 // Check possible region
 660                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 661                 {
 662                         // If there is an allocated page in the region we are testing, break
 663                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 664                 }
 665                 // Is it all free?
 666                 if( j == Number )
 667                 {
 668                         // Allocate
 669                         for( j = 0; j < Number; j++ ) {
 670                                 MM_RefPhys( PAddr + (j<<12) );
 671                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 672                         }
 673                         return HW_MAP_ADDR + (i<<12);
 674                 }
 675         }
 676         // If we don't find any, return NULL
 677         return 0;
 678 }
 679
 680 /**
 681  * \fn void MM_UnmapHWPage(Uint VAddr, Uint Number)
 682  * \brief Unmap a hardware page
 683  */
 684 void MM_UnmapHWPage(Uint VAddr, Uint Number)
 685 {
 686          int    i, j;
 687         // Sanity Check
 688         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 689
 690         i = VAddr >> 12;
 691
 692         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 693
 694         for( j = 0; j < Number; j++ )
 695         {
 696                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 697                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 698         }
 699
 700         RELEASE( &gilTempMappings );
 701 }
 702
 703 // --- EXPORTS ---
 704 EXPORT(MM_GetPhysAddr);
 705 EXPORT(MM_Map);
 706 //EXPORT(MM_Unmap);
 707 EXPORT(MM_MapHWPage);
 708 EXPORT(MM_UnmapHWPage);