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 #define DEBUG   1
  13 #include <common.h>
  14 #include <mm_phys.h>
  15 #include <proc.h>
  16
  17 #define KERNEL_STACKS   0xF0000000
  18 #define KERNEL_STACK_SIZE       0x00002000
  19 #define KERNEL_STACK_END        0xFD000000
  20 #define PAGE_TABLE_ADDR 0xFD000000
  21 #define PAGE_DIR_ADDR   0xFD3F4000
  22 #define PAGE_CR3_ADDR   0xFD3F4FD0
  23 #define TMP_CR3_ADDR    0xFD3F4FD4      // Part of core instead of temp
  24 #define TMP_DIR_ADDR    0xFD3F5000      // Same
  25 #define TMP_TABLE_ADDR  0xFD400000
  26 #define HW_MAP_ADDR             0xFD800000
  27 #define HW_MAP_MAX              0xFEFF0000
  28 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  29 #define TEMP_MAP_ADDR   0xFEFF0000      // Allows 16 "temp" pages
  30 #define NUM_TEMP_PAGES  16
  31
  32 #define PF_PRESENT      0x1
  33 #define PF_WRITE        0x2
  34 #define PF_USER         0x4
  35 #define PF_COW          0x200
  36 #define PF_PAGED        0x400
  37
  38 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  39
  40 // === IMPORTS ===
  41 extern Uint32   gaInitPageDir[1024];
  42 extern Uint32   gaInitPageTable[1024];
  43
  44 // === PROTOTYPES ===
  45 void    MM_PreinitVirtual();
  46 void    MM_InstallVirtual();
  47 void    MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs);
  48 void    MM_DumpTables(tVAddr Start, tVAddr End);
  49 tPAddr  MM_DuplicatePage(Uint VAddr);
  50
  51 // === GLOBALS ===
  52 tPAddr  *gaPageTable = (void*)PAGE_TABLE_ADDR;
  53 tPAddr  *gaPageDir = (void*)PAGE_DIR_ADDR;
  54 tPAddr  *gaPageCR3 = (void*)PAGE_CR3_ADDR;
  55 tPAddr  *gaTmpTable = (void*)TMP_TABLE_ADDR;
  56 tPAddr  *gaTmpDir = (void*)TMP_DIR_ADDR;
  57 tPAddr  *gTmpCR3 = (void*)TMP_CR3_ADDR;
  58  int    gilTempMappings = 0;
  59
  60 // === CODE ===
  61 /**
  62  * \fn void MM_PreinitVirtual()
  63  * \brief Maps the fractal mappings
  64  */
  65 void MM_PreinitVirtual()
  66 {
  67         gaInitPageDir[ 0 ] = 0;
  68         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((Uint)&gaInitPageDir - KERNEL_BASE) | 3;
  69 }
  70
  71 /**
  72  * \fn void MM_InstallVirtual()
  73  * \brief Sets up the constant page mappings
  74  */
  75 void MM_InstallVirtual()
  76 {
  77          int    i;
  78
  79         // --- Pre-Allocate kernel tables
  80         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
  81         {
  82                 if( gaPageDir[ i ] )    continue;
  83                 // Skip stack tables, they are process unique
  84                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACK_END >> 22) {
  85                         gaPageDir[ i ] = 0;
  86                         continue;
  87                 }
  88                 // Preallocate table
  89                 gaPageDir[ i ] = MM_AllocPhys() | 3;
  90                 INVLPG( &gaPageTable[i*1024] );
  91                 memset( &gaPageTable[i*1024], 0, 0x1000 );
  92         }
  93 }
  94
  95 /**
  96  * \fn void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
  97  * \brief Called on a page fault
  98  */
  99 void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
 100 {
 101         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 102
 103         // -- Check for COW --
 104         if( gaPageDir  [Addr>>22] & PF_PRESENT
 105          && gaPageTable[Addr>>12] & PF_PRESENT
 106          && gaPageTable[Addr>>12] & PF_COW )
 107         {
 108                 tPAddr  paddr;
 109                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 110                 {
 111                         gaPageTable[Addr>>12] &= ~PF_COW;
 112                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 113                 }
 114                 else
 115                 {
 116                         paddr = MM_DuplicatePage( Addr );
 117                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 118                         gaPageTable[Addr>>12] &= PF_USER;
 119                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 120                 }
 121                 LOG("Duplicated page at %p to 0x%x", Addr&~0xFFF, gaPageTable[Addr>>12]);
 122                 INVLPG( Addr & ~0xFFF );
 123                 //LEAVE('-')
 124                 return;
 125         }
 126
 127         // -- Check Error Code --
 128         if(ErrorCode & 8)
 129                 Warning("Reserved Bits Trashed!");
 130         else
 131         {
 132                 Warning("%s %s %s memory%s",
 133                         (ErrorCode&4?"User":"Kernel"),
 134                         (ErrorCode&2?"write to":"read from"),
 135                         (ErrorCode&1?"bad/locked":"non-present"),
 136                         (ErrorCode&16?" (Instruction Fetch)":"")
 137                         );
 138         }
 139
 140         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 141         if( gaPageDir[Addr>>22] & PF_PRESENT )
 142                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 143
 144         MM_DumpTables(0, -1);
 145
 146         Panic("Page Fault at 0x%x\n", Regs->eip);
 147 }
 148
 149 /**
 150  * \fn void MM_DumpTables(Uint Start, Uint End)
 151  * \brief Dumps the layout of the page tables
 152  */
 153 void MM_DumpTables(tVAddr Start, tVAddr End)
 154 {
 155         tVAddr  rangeStart = 0;
 156         tPAddr  expected = 0;
 157         tVAddr  curPos;
 158         Uint    page;
 159         const tPAddr    MASK = ~0xF98;
 160
 161         Start >>= 12;   End >>= 12;
 162         for(page = Start, curPos = Start<<12;
 163                 page < End;
 164                 curPos += 0x1000, page++)
 165         {
 166                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 167                 ||  !(gaPageTable[page] & PF_PRESENT)
 168                 ||  (gaPageTable[page] & MASK) != expected)
 169                 {
 170                         if(expected) {
 171                                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 172                                         rangeStart, curPos - 1,
 173                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 174                                         (expected & ~0xFFF) - 1,
 175                                         (expected & PF_PAGED ? "p" : "-"),
 176                                         (expected & PF_COW ? "C" : "-"),
 177                                         (expected & PF_USER ? "U" : "-"),
 178                                         (expected & PF_WRITE ? "W" : "-")
 179                                         );
 180                                 expected = 0;
 181                         }
 182                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 183                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 184
 185                         expected = (gaPageTable[page] & MASK);
 186                         rangeStart = curPos;
 187                 }
 188                 if(expected)    expected += 0x1000;
 189         }
 190
 191         if(expected) {
 192                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 193                         rangeStart, curPos - 1,
 194                         gaPageTable[rangeStart>>12] & ~0xFFF,
 195                         (expected & ~0xFFF) - 1,
 196                         (expected & PF_PAGED ? "p" : "-"),
 197                         (expected & PF_COW ? "C" : "-"),
 198                         (expected & PF_USER ? "U" : "-"),
 199                         (expected & PF_WRITE ? "W" : "-")
 200                         );
 201                 expected = 0;
 202         }
 203 }
 204
 205 /**
 206  * \fn tPAddr MM_Allocate(Uint VAddr)
 207  */
 208 tPAddr MM_Allocate(Uint VAddr)
 209 {
 210         tPAddr  paddr;
 211         // Check if the directory is mapped
 212         if( gaPageDir[ VAddr >> 22 ] == 0 )
 213         {
 214                 // Allocate directory
 215                 paddr = MM_AllocPhys();
 216                 if( paddr == 0 ) {
 217                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 218                         return 0;
 219                 }
 220                 // Map
 221                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 222                 // Mark as user
 223                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 224
 225                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 226                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 227         }
 228         // Check if the page is already allocated
 229         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 230                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 231                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 232         }
 233
 234         // Allocate
 235         paddr = MM_AllocPhys();
 236         if( paddr == 0 ) {
 237                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 238                         VAddr, __builtin_return_address(0));
 239                 return 0;
 240         }
 241         // Map
 242         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 243         // Mark as user
 244         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 245         // Invalidate Cache for address
 246         INVLPG( VAddr & ~0xFFF );
 247
 248         return paddr;
 249 }
 250
 251 /**
 252  * \fn void MM_Deallocate(Uint VAddr)
 253  */
 254 void MM_Deallocate(Uint VAddr)
 255 {
 256         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 257                 Warning("MM_Deallocate - Directory not mapped");
 258                 return;
 259         }
 260
 261         if(gaPageTable[ VAddr >> 12 ] == 0) {
 262                 Warning("MM_Deallocate - Page is not allocated");
 263                 return;
 264         }
 265
 266         // Dereference page
 267         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 268         // Clear page
 269         gaPageTable[ VAddr >> 12 ] = 0;
 270 }
 271
 272 /**
 273  * \fn tPAddr MM_GetPhysAddr(Uint Addr)
 274  * \brief Checks if the passed address is accesable
 275  */
 276 tPAddr MM_GetPhysAddr(Uint Addr)
 277 {
 278         if( !(gaPageDir[Addr >> 22] & 1) )
 279                 return 0;
 280         if( !(gaPageTable[Addr >> 12] & 1) )
 281                 return 0;
 282         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 283 }
 284
 285 /**
 286  * \fn void MM_SetCR3(Uint CR3)
 287  * \brief Sets the current process space
 288  */
 289 void MM_SetCR3(Uint CR3)
 290 {
 291         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 292 }
 293
 294 /**
 295  * \fn int MM_Map(Uint VAddr, tPAddr PAddr)
 296  * \brief Map a physical page to a virtual one
 297  */
 298 int MM_Map(Uint VAddr, tPAddr PAddr)
 299 {
 300         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 301         // Sanity check
 302         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 303                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 304                 //LEAVE('i', 0);
 305                 return 0;
 306         }
 307
 308         // Align addresses
 309         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 310
 311         // Check if the directory is mapped
 312         if( gaPageDir[ VAddr >> 22 ] == 0 )
 313         {
 314                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 315
 316                 // Mark as user
 317                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 318
 319                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 320                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 321         }
 322         // Check if the page is already allocated
 323         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 324                 Warning("MM_Map - Allocating to used address");
 325                 //LEAVE('i', 0);
 326                 return 0;
 327         }
 328
 329         // Map
 330         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 331         // Mark as user
 332         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 333
 334         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 335         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 336
 337         // Reference
 338         MM_RefPhys( PAddr );
 339
 340         //LOG("INVLPG( 0x%x )", VAddr);
 341         INVLPG( VAddr );
 342
 343         //LEAVE('i', 1);
 344         return 1;
 345 }
 346
 347 /**
 348  * \fn Uint MM_ClearUser()
 349  * \brief Clear user's address space
 350  */
 351 Uint MM_ClearUser()
 352 {
 353         Uint    i, j;
 354
 355         // Copy Directories
 356         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 357         {
 358                 // Check if directory is not allocated
 359                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 360                         gaPageDir[i] = 0;
 361                         continue;
 362                 }
 363
 364
 365                 for( j = 0; j < 1024; j ++ )
 366                 {
 367                         if( gaPageTable[i*1024+j] & 1 )
 368                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 369                         gaPageTable[i*1024+j] = 0;
 370                 }
 371
 372                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 373         }
 374
 375
 376         return *gTmpCR3;
 377 }
 378
 379 /**
 380  * \fn Uint MM_Clone()
 381  * \brief Clone the current address space
 382  */
 383 Uint MM_Clone()
 384 {
 385         Uint    i, j;
 386         Uint    kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 387         void    *tmp;
 388
 389         //ENTER("");
 390
 391         // Create Directory Table
 392         *gTmpCR3 = MM_AllocPhys() | 3;
 393         INVLPG( gaTmpDir );
 394         //LOG("Allocated Directory (%x)", *gTmpCR3);
 395         memsetd( gaTmpDir, 0, 1024 );
 396
 397         // Copy Tables
 398         for(i=0;i<768;i++)
 399         {
 400                 // Check if table is allocated
 401                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 402                         gaTmpDir[i] = 0;
 403                         continue;
 404                 }
 405
 406                 // Allocate new table
 407                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 408                 INVLPG( &gaTmpTable[i*1024] );
 409                 // Fill
 410                 for( j = 0; j < 1024; j ++ )
 411                 {
 412                         if( !(gaPageTable[i*1024+j] & PF_PRESENT) ) {
 413                                 gaTmpTable[i*1024+j] = 0;
 414                                 continue;
 415                         }
 416
 417                         // Refrence old page
 418                         MM_RefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 419                         // Add to new table
 420                         if(gaPageTable[i*1024+j] & PF_WRITE) {
 421                                 gaTmpTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 422                                 gaPageTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 423                         }
 424                         else
 425                                 gaTmpTable[i*1024+j] = gaPageTable[i*1024+j];
 426                 }
 427         }
 428
 429         // Map in kernel tables (and make fractal mapping)
 430         for( i = 768; i < 1024; i ++ )
 431         {
 432                 // Fractal
 433                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 434                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 435                         continue;
 436                 }
 437
 438                 if( gaPageDir[i] == 0 ) {
 439                         gaTmpDir[i] = 0;
 440                         continue;
 441                 }
 442
 443                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 444                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 445                 gaTmpDir[i] = gaPageDir[i];
 446         }
 447
 448         // Allocate kernel stack
 449         for(i = KERNEL_STACKS >> 22;
 450                 i < KERNEL_STACK_END >> 22;
 451                 i ++ )
 452         {
 453                 // Check if directory is allocated
 454                 if( (gaPageDir[i] & 1) == 0 ) {
 455                         gaTmpDir[i] = 0;
 456                         continue;
 457                 }
 458
 459                 // We don't care about other kernel stacks, just the current one
 460                 if( i != kStackBase >> 22 ) {
 461                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 462                         gaTmpDir[i] = 0;
 463                         continue;
 464                 }
 465
 466                 // Create a copy
 467                 gaTmpDir[i] = MM_AllocPhys() | 3;
 468                 INVLPG( &gaTmpTable[i*1024] );
 469                 for( j = 0; j < 1024; j ++ )
 470                 {
 471                         // Is the page allocated? If not, skip
 472                         if( !(gaPageTable[i*1024+j] & 1) ) {
 473                                 gaTmpTable[i*1024+j] = 0;
 474                                 continue;
 475                         }
 476
 477                         // We don't care about other kernel stacks
 478                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 479                                 gaTmpTable[i*1024+j] = 0;
 480                                 continue;
 481                         }
 482
 483                         // Allocate page
 484                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 485
 486                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 487
 488                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 489                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 490                         MM_FreeTemp( (Uint)tmp );
 491                 }
 492         }
 493
 494         //LEAVE('x', *gTmpCR3 & ~0xFFF);
 495         return *gTmpCR3 & ~0xFFF;
 496 }
 497
 498 /**
 499  * \fn Uint MM_NewKStack()
 500  * \brief Create a new kernel stack
 501  */
 502 Uint MM_NewKStack()
 503 {
 504         Uint    base = KERNEL_STACKS;
 505         Uint    i;
 506         for(;base<KERNEL_STACK_END;base+=KERNEL_STACK_SIZE)
 507         {
 508                 if(MM_GetPhysAddr(base) != 0)   continue;
 509                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 510                         MM_Allocate(base+i);
 511                 }
 512                 return base+KERNEL_STACK_SIZE;
 513         }
 514         Warning("MM_NewKStack - No address space left\n");
 515         return 0;
 516 }
 517
 518 /**
 519  * \fn void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 520  * \brief Sets the flags on a page
 521  */
 522 void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 523 {
 524         tPAddr  *ent;
 525         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 526         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 527
 528         ent = &gaPageTable[VAddr >> 12];
 529
 530         // Read-Only
 531         if( Mask & MM_PFLAG_RO )
 532         {
 533                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 534                 else    *ent |= PF_WRITE;
 535         }
 536
 537         // Kernel
 538         if( Mask & MM_PFLAG_KERNEL )
 539         {
 540                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 541                 else    *ent |= PF_USER;
 542         }
 543
 544         // Copy-On-Write
 545         if( Mask & MM_PFLAG_COW )
 546         {
 547                 if( Flags & MM_PFLAG_COW ) {
 548                         *ent &= ~PF_WRITE;
 549                         *ent |= PF_COW;
 550                 }
 551                 else {
 552                         *ent &= ~PF_COW;
 553                         *ent |= PF_WRITE;
 554                 }
 555         }
 556 }
 557
 558 /**
 559  * \fn tPAddr MM_DuplicatePage(Uint VAddr)
 560  * \brief Duplicates a virtual page to a physical one
 561  */
 562 tPAddr MM_DuplicatePage(Uint VAddr)
 563 {
 564         tPAddr  ret;
 565         Uint    temp;
 566          int    wasRO = 0;
 567
 568         // Check if mapped
 569         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 570         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 571
 572         // Page Align
 573         VAddr &= ~0xFFF;
 574
 575         // Allocate new page
 576         ret = MM_AllocPhys();
 577
 578         // Write-lock the page (to keep data constistent), saving its R/W state
 579         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 580         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 581         INVLPG( VAddr );
 582
 583         // Copy Data
 584         temp = MM_MapTemp(ret);
 585         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 586         MM_FreeTemp(temp);
 587
 588         // Restore Writeable status
 589         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 590         INVLPG(VAddr);
 591
 592         return ret;
 593 }
 594
 595 /**
 596  * \fn Uint MM_MapTemp(tPAddr PAddr)
 597  * \brief Create a temporary memory mapping
 598  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 599  */
 600 Uint MM_MapTemp(tPAddr PAddr)
 601 {
 602          int    i;
 603
 604         //ENTER("XPAddr", PAddr);
 605
 606         PAddr &= ~0xFFF;
 607
 608         //LOG("gilTempMappings = %i", gilTempMappings);
 609
 610         for(;;)
 611         {
 612                 LOCK( &gilTempMappings );
 613
 614                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 615                 {
 616                         // Check if page used
 617                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 618                         // Mark as used
 619                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 620                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 621                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 622                         RELEASE( &gilTempMappings );
 623                         return TEMP_MAP_ADDR + (i << 12);
 624                 }
 625                 RELEASE( &gilTempMappings );
 626                 Threads_Yield();
 627         }
 628 }
 629
 630 /**
 631  * \fn void MM_FreeTemp(Uint PAddr)
 632  * \brief Free's a temp mapping
 633  */
 634 void MM_FreeTemp(Uint VAddr)
 635 {
 636          int    i = VAddr >> 12;
 637         //ENTER("xVAddr", VAddr);
 638
 639         if(i >= (TEMP_MAP_ADDR >> 12))
 640                 gaPageTable[ i ] = 0;
 641
 642         //LEAVE('-');
 643 }
 644
 645 /**
 646  * \fn Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 647  * \brief Allocates a contigous number of pages
 648  */
 649 Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 650 {
 651          int    i, j;
 652
 653         PAddr &= ~0xFFF;
 654
 655         // Scan List
 656         for( i = 0; i < NUM_HW_PAGES; i ++ )
 657         {
 658                 // Check if addr used
 659                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 660                         continue;
 661
 662                 // Check possible region
 663                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 664                 {
 665                         // If there is an allocated page in the region we are testing, break
 666                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 667                 }
 668                 // Is it all free?
 669                 if( j == Number )
 670                 {
 671                         // Allocate
 672                         for( j = 0; j < Number; j++ ) {
 673                                 MM_RefPhys( PAddr + (j<<12) );
 674                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 675                         }
 676                         return HW_MAP_ADDR + (i<<12);
 677                 }
 678         }
 679         // If we don't find any, return NULL
 680         return 0;
 681 }
 682
 683 /**
 684  * \fn void MM_UnmapHWPage(Uint VAddr, Uint Number)
 685  * \brief Unmap a hardware page
 686  */
 687 void MM_UnmapHWPage(Uint VAddr, Uint Number)
 688 {
 689          int    i, j;
 690         // Sanity Check
 691         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 692
 693         i = VAddr >> 12;
 694
 695         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 696
 697         for( j = 0; j < Number; j++ )
 698         {
 699                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 700                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 701         }
 702
 703         RELEASE( &gilTempMappings );
 704 }
 705
 706 // --- EXPORTS ---
 707 EXPORT(MM_GetPhysAddr);
 708 EXPORT(MM_Map);
 709 //EXPORT(MM_Unmap);
 710 EXPORT(MM_MapHWPage);
 711 EXPORT(MM_UnmapHWPage);