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 0xFD3F47F4
  22 //#define TMP_CR3_ADDR  0xFD3F47F8      // Part of core instead of temp
  23 #define PAGE_CR3_ADDR   0xFD3F4FD0
  24 #define TMP_CR3_ADDR    0xFD3F4FD4      // Part of core instead of temp
  25 #define TMP_DIR_ADDR    0xFD3F5000      // Same
  26 #define TMP_TABLE_ADDR  0xFD400000
  27 #define HW_MAP_ADDR             0xFD800000
  28 #define HW_MAP_MAX              0xFEFF0000
  29 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  30 #define TEMP_MAP_ADDR   0xFEFF0000      // Allows 16 "temp" pages
  31 #define NUM_TEMP_PAGES  16
  32
  33 #define USE_COW 1
  34
  35 #define PF_PRESENT      0x1
  36 #define PF_WRITE        0x2
  37 #define PF_USER         0x4
  38 #define PF_COW          0x200
  39 #define PF_PAGED        0x400
  40
  41 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  42
  43 // === IMPORTS ===
  44 extern Uint32   gaInitPageDir[1024];
  45 extern Uint32   gaInitPageTable[1024];
  46
  47 // === PROTOTYPES ===
  48 void    MM_PreinitVirtual();
  49 void    MM_InstallVirtual();
  50 void    MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs);
  51 void    MM_DumpTables(tVAddr Start, tVAddr End);
  52 tPAddr  MM_DuplicatePage(Uint VAddr);
  53
  54 // === GLOBALS ===
  55 tPAddr  *gaPageTable = (void*)PAGE_TABLE_ADDR;
  56 tPAddr  *gaPageDir = (void*)PAGE_DIR_ADDR;
  57 tPAddr  *gaPageCR3 = (void*)PAGE_CR3_ADDR;
  58 tPAddr  *gaTmpTable = (void*)TMP_TABLE_ADDR;
  59 tPAddr  *gaTmpDir = (void*)TMP_DIR_ADDR;
  60 tPAddr  *gTmpCR3 = (void*)TMP_CR3_ADDR;
  61  int    gilTempMappings = 0;
  62
  63 // === CODE ===
  64 /**
  65  * \fn void MM_PreinitVirtual()
  66  */
  67 void MM_PreinitVirtual()
  68 {
  69         gaInitPageDir[ 0 ] = 0;
  70         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((Uint)&gaInitPageDir - KERNEL_BASE) | 3;
  71 }
  72 /**
  73  * \fn void MM_InstallVirtual()
  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                 paddr = MM_DuplicatePage( Addr );
 110                 MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 111                 gaPageTable[Addr>>12] &= PF_USER;
 112                 gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 113                 INVLPG( Addr & ~0xFFF );
 114         }
 115
 116         // -- Check Error Code --
 117         if(ErrorCode & 8)
 118                 Warning("Reserved Bits Trashed!");
 119         else
 120         {
 121                 Warning("%s %s %s memory%s",
 122                         (ErrorCode&4?"User":"Kernel"),
 123                         (ErrorCode&2?"write to":"read from"),
 124                         (ErrorCode&1?"bad/locked":"non-present"),
 125                         (ErrorCode&16?" (Instruction Fetch)":"")
 126                         );
 127         }
 128
 129         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 130         if( gaPageDir[Addr>>22] & PF_PRESENT )
 131                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 132
 133         MM_DumpTables(0, -1);
 134
 135         Panic("Page Fault at 0x%x\n", Regs->eip);
 136         LEAVE('-');
 137 }
 138
 139 /**
 140  * \fn void MM_DumpTables(Uint Start, Uint End)
 141  * \brief Dumps the layout of the page tables
 142  */
 143 void MM_DumpTables(tVAddr Start, tVAddr End)
 144 {
 145         tVAddr  rangeStart = 0;
 146         tPAddr  expected = 0;
 147         tVAddr  curPos;
 148         Uint    page;
 149         const tPAddr    MASK = ~0xF98;
 150
 151         Start >>= 12;   End >>= 12;
 152         for(page = Start, curPos = Start<<12;
 153                 page < End;
 154                 curPos += 0x1000, page++)
 155         {
 156                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 157                 ||  !(gaPageTable[page] & PF_PRESENT)
 158                 ||  (gaPageTable[page] & MASK) != expected)
 159                 {
 160                         if(expected) {
 161                                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 162                                         rangeStart, curPos - 1,
 163                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 164                                         (expected & ~0xFFF) - 1,
 165                                         (expected & PF_PAGED ? "p" : "-"),
 166                                         (expected & PF_COW ? "C" : "-"),
 167                                         (expected & PF_USER ? "U" : "-"),
 168                                         (expected & PF_WRITE ? "W" : "-")
 169                                         );
 170                                 expected = 0;
 171                         }
 172                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 173                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 174
 175                         expected = (gaPageTable[page] & MASK);
 176                         rangeStart = curPos;
 177                 }
 178                 if(expected)    expected += 0x1000;
 179         }
 180
 181         if(expected) {
 182                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 183                         rangeStart, curPos - 1,
 184                         gaPageTable[rangeStart>>12] & ~0xFFF,
 185                         (expected & ~0xFFF) - 1,
 186                         (expected & PF_PAGED ? "p" : "-"),
 187                         (expected & PF_COW ? "C" : "-"),
 188                         (expected & PF_USER ? "U" : "-"),
 189                         (expected & PF_WRITE ? "W" : "-")
 190                         );
 191                 expected = 0;
 192         }
 193 }
 194
 195 /**
 196  * \fn tPAddr MM_Allocate(Uint VAddr)
 197  */
 198 tPAddr MM_Allocate(Uint VAddr)
 199 {
 200         // Check if the directory is mapped
 201         if( gaPageDir[ VAddr >> 22 ] == 0 )
 202         {
 203                 // Allocate directory
 204                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 205                 // Mark as user
 206                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 207
 208                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 209                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 210         }
 211         // Check if the page is already allocated
 212         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 213                 Warning("MM_Allocate - Allocating to used address");
 214                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 215         }
 216
 217         // Allocate
 218         gaPageTable[ VAddr >> 12 ] = MM_AllocPhys() | 3;
 219         // Mark as user
 220         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 221         // Invalidate Cache for address
 222         INVLPG( VAddr & ~0xFFF );
 223
 224         return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 225 }
 226
 227 /**
 228  * \fn void MM_Deallocate(Uint VAddr)
 229  */
 230 void MM_Deallocate(Uint VAddr)
 231 {
 232         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 233                 Warning("MM_Deallocate - Directory not mapped");
 234                 return;
 235         }
 236
 237         if(gaPageTable[ VAddr >> 12 ] == 0) {
 238                 Warning("MM_Deallocate - Page is not allocated");
 239                 return;
 240         }
 241
 242         // Dereference page
 243         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 244         // Clear page
 245         gaPageTable[ VAddr >> 12 ] = 0;
 246 }
 247
 248 /**
 249  * \fn tPAddr MM_GetPhysAddr(Uint Addr)
 250  * \brief Checks if the passed address is accesable
 251  */
 252 tPAddr MM_GetPhysAddr(Uint Addr)
 253 {
 254         if( !(gaPageDir[Addr >> 22] & 1) )
 255                 return 0;
 256         if( !(gaPageTable[Addr >> 12] & 1) )
 257                 return 0;
 258         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 259 }
 260
 261 /**
 262  * \fn void MM_SetCR3(Uint CR3)
 263  * \brief Sets the current process space
 264  */
 265 void MM_SetCR3(Uint CR3)
 266 {
 267         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 268 }
 269
 270 /**
 271  * \fn int MM_Map(Uint VAddr, tPAddr PAddr)
 272  * \brief Map a physical page to a virtual one
 273  */
 274 int MM_Map(Uint VAddr, tPAddr PAddr)
 275 {
 276         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 277         // Sanity check
 278         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 279                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 280                 //LEAVE('i', 0);
 281                 return 0;
 282         }
 283
 284         // Align addresses
 285         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 286
 287         // Check if the directory is mapped
 288         if( gaPageDir[ VAddr >> 22 ] == 0 )
 289         {
 290                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 291
 292                 // Mark as user
 293                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 294
 295                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 296                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 297         }
 298         // Check if the page is already allocated
 299         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 300                 Warning("MM_Map - Allocating to used address");
 301                 //LEAVE('i', 0);
 302                 return 0;
 303         }
 304
 305         // Map
 306         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 307         // Mark as user
 308         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 309
 310         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 311         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 312
 313         // Reference
 314         MM_RefPhys( PAddr );
 315
 316         //LOG("INVLPG( 0x%x )", VAddr);
 317         INVLPG( VAddr );
 318
 319         //LEAVE('i', 1);
 320         return 1;
 321 }
 322
 323 /**
 324  * \fn Uint MM_ClearUser()
 325  * \brief Clear user's address space
 326  */
 327 Uint MM_ClearUser()
 328 {
 329         Uint    i, j;
 330
 331         // Copy Directories
 332         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 333         {
 334                 // Check if directory is not allocated
 335                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 336                         gaPageDir[i] = 0;
 337                         continue;
 338                 }
 339
 340
 341                 for( j = 0; j < 1024; j ++ )
 342                 {
 343                         if( gaPageTable[i*1024+j] & 1 )
 344                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 345                         gaPageTable[i*1024+j] = 0;
 346                 }
 347
 348                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 349         }
 350
 351
 352         return *gTmpCR3;
 353 }
 354
 355 /**
 356  * \fn Uint MM_Clone()
 357  * \brief Clone the current address space
 358  */
 359 Uint MM_Clone()
 360 {
 361         Uint    i, j;
 362         Uint    kStackBase = gCurrentThread->KernelStack - KERNEL_STACK_SIZE;
 363         void    *tmp;
 364
 365         //ENTER("");
 366
 367         // Create Directory Table
 368         *gTmpCR3 = MM_AllocPhys() | 3;
 369         INVLPG( gaTmpDir );
 370         //LOG("Allocated Directory (%x)", *gTmpCR3);
 371         memsetd( gaTmpDir, 0, 1024 );
 372
 373         // Copy Tables
 374         for(i=0;i<768;i++)
 375         {
 376                 // Check if table is allocated
 377                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 378                         gaTmpDir[i] = 0;
 379                         continue;
 380                 }
 381
 382                 // Allocate new table
 383                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 384                 INVLPG( &gaTmpTable[i*1024] );
 385                 // Fill
 386                 for( j = 0; j < 1024; j ++ )
 387                 {
 388                         if( !(gaPageTable[i*1024+j] & PF_PRESENT) ) {
 389                                 gaTmpTable[i*1024+j] = 0;
 390                                 continue;
 391                         }
 392
 393                         #if USE_COW
 394                         // Refrence old page
 395                         MM_RefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 396                         // Add to new table
 397                         if(gaPageTable[i*1024+j] & PF_WRITE) {
 398                                 gaTmpTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 399                                 gaPageTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 400                         }
 401                         else
 402                                 gaTmpTable[i*1024+j] = gaPageTable[i*1024+j];
 403                         LOG("gaTmpTable[0x%x] = 0x%x", i*1024+j, gaTmpTable[i*1024+j]);
 404                         #else
 405                         gaTmpTable[i*1024+j] = MM_DuplicatePage( (i*1024+j)<<12 ) | (gaPageTable[i*1024+j]&7);
 406                         #endif
 407                 }
 408         }
 409
 410         // Map in kernel tables (and make fractal mapping)
 411         for( i = 768; i < 1024; i ++ )
 412         {
 413                 // Fractal
 414                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 415                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 416                         continue;
 417                 }
 418
 419                 if( gaPageDir[i] == 0 ) {
 420                         gaTmpDir[i] = 0;
 421                         continue;
 422                 }
 423
 424                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 425                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 426                 gaTmpDir[i] = gaPageDir[i];
 427         }
 428
 429         // Allocate kernel stack
 430         for(i = KERNEL_STACKS >> 22;
 431                 i < KERNEL_STACK_END >> 22;
 432                 i ++ )
 433         {
 434                 // Check if directory is allocated
 435                 if( (gaPageDir[i] & 1) == 0 ) {
 436                         gaTmpDir[i] = 0;
 437                         continue;
 438                 }
 439
 440                 // We don't care about other kernel stacks, just the current one
 441                 if( i != kStackBase >> 22 ) {
 442                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 443                         gaTmpDir[i] = 0;
 444                         continue;
 445                 }
 446
 447                 // Create a copy
 448                 gaTmpDir[i] = MM_AllocPhys() | 3;
 449                 INVLPG( &gaTmpTable[i*1024] );
 450                 for( j = 0; j < 1024; j ++ )
 451                 {
 452                         // Is the page allocated? If not, skip
 453                         if( !(gaPageTable[i*1024+j] & 1) ) {
 454                                 gaTmpTable[i*1024+j] = 0;
 455                                 continue;
 456                         }
 457
 458                         // We don't care about other kernel stacks
 459                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 460                                 gaTmpTable[i*1024+j] = 0;
 461                                 continue;
 462                         }
 463
 464                         // Allocate page
 465                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 466
 467                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 468
 469                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 470                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 471                         MM_FreeTemp( (Uint)tmp );
 472                 }
 473         }
 474
 475         //LEAVE('x', *gTmpCR3 & ~0xFFF);
 476         return *gTmpCR3 & ~0xFFF;
 477 }
 478
 479 /**
 480  * \fn Uint MM_NewKStack()
 481  * \brief Create a new kernel stack
 482  */
 483 Uint MM_NewKStack()
 484 {
 485         Uint    base = KERNEL_STACKS;
 486         Uint    i;
 487         for(;base<KERNEL_STACK_END;base+=KERNEL_STACK_SIZE)
 488         {
 489                 if(MM_GetPhysAddr(base) != 0)   continue;
 490                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 491                         MM_Allocate(base+i);
 492                 }
 493                 return base+KERNEL_STACK_SIZE;
 494         }
 495         Warning("MM_NewKStack - No address space left\n");
 496         return 0;
 497 }
 498
 499 /**
 500  * \fn void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 501  * \brief Sets the flags on a page
 502  */
 503 void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 504 {
 505         tPAddr  *ent;
 506         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 507         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 508
 509         ent = &gaPageTable[VAddr >> 12];
 510
 511         // Read-Only
 512         if( Mask & MM_PFLAG_RO )
 513         {
 514                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 515                 else    *ent |= PF_WRITE;
 516         }
 517
 518         // Kernel
 519         if( Mask & MM_PFLAG_KERNEL )
 520         {
 521                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 522                 else    *ent |= PF_USER;
 523         }
 524 }
 525
 526 /**
 527  * \fn tPAddr MM_DuplicatePage(Uint VAddr)
 528  * \brief Duplicates a virtual page to a physical one
 529  */
 530 tPAddr MM_DuplicatePage(Uint VAddr)
 531 {
 532         tPAddr  ret;
 533         Uint    temp;
 534          int    wasRO = 0;
 535
 536         // Check if mapped
 537         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 538         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 539
 540         // Page Align
 541         VAddr &= ~0xFFF;
 542
 543         // Allocate new page
 544         ret = MM_AllocPhys();
 545
 546         // Write-lock the page (to keep data constistent), saving its R/W state
 547         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 548         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 549         INVLPG( VAddr );
 550
 551         // Copy Data
 552         temp = MM_MapTemp(ret);
 553         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 554         MM_FreeTemp(temp);
 555
 556         // Restore Writeable status
 557         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 558         INVLPG(VAddr);
 559
 560         return ret;
 561 }
 562
 563 /**
 564  * \fn Uint MM_MapTemp(tPAddr PAddr)
 565  * \brief Create a temporary memory mapping
 566  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 567  */
 568 Uint MM_MapTemp(tPAddr PAddr)
 569 {
 570          int    i;
 571
 572         //ENTER("XPAddr", PAddr);
 573
 574         PAddr &= ~0xFFF;
 575
 576         //LOG("gilTempMappings = %i", gilTempMappings);
 577
 578         for(;;)
 579         {
 580                 LOCK( &gilTempMappings );
 581
 582                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 583                 {
 584                         // Check if page used
 585                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 586                         // Mark as used
 587                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 588                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 589                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 590                         RELEASE( &gilTempMappings );
 591                         return TEMP_MAP_ADDR + (i << 12);
 592                 }
 593                 RELEASE( &gilTempMappings );
 594                 Proc_Yield();
 595         }
 596 }
 597
 598 /**
 599  * \fn void MM_FreeTemp(Uint PAddr)
 600  * \brief Free's a temp mapping
 601  */
 602 void MM_FreeTemp(Uint VAddr)
 603 {
 604          int    i = VAddr >> 12;
 605         //ENTER("xVAddr", VAddr);
 606
 607         if(i >= (TEMP_MAP_ADDR >> 12))
 608                 gaPageTable[ i ] = 0;
 609
 610         //LEAVE('-');
 611 }
 612
 613 /**
 614  * \fn Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 615  * \brief Allocates a contigous number of pages
 616  */
 617 Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 618 {
 619          int    i, j;
 620
 621         PAddr &= ~0xFFF;
 622
 623         // Scan List
 624         for( i = 0; i < NUM_HW_PAGES; i ++ )
 625         {
 626                 // Check if addr used
 627                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 628                         continue;
 629
 630                 // Check possible region
 631                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 632                 {
 633                         // If there is an allocated page in the region we are testing, break
 634                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 635                 }
 636                 // Is it all free?
 637                 if( j == Number )
 638                 {
 639                         // Allocate
 640                         for( j = 0; j < Number; j++ ) {
 641                                 MM_RefPhys( PAddr + (j<<12) );
 642                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 643                         }
 644                         return HW_MAP_ADDR + (i<<12);
 645                 }
 646         }
 647         // If we don't find any, return NULL
 648         return 0;
 649 }
 650
 651 /**
 652  * \fn void MM_UnmapHWPage(Uint VAddr, Uint Number)
 653  * \brief Unmap a hardware page
 654  */
 655 void MM_UnmapHWPage(Uint VAddr, Uint Number)
 656 {
 657          int    i, j;
 658         // Sanity Check
 659         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 660
 661         i = VAddr >> 12;
 662
 663         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 664
 665         for( j = 0; j < Number; j++ )
 666         {
 667                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 668                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 669         }
 670
 671         RELEASE( &gilTempMappings );
 672 }
 673
 674 // --- EXPORTS ---
 675 EXPORT(MM_GetPhysAddr);
 676 EXPORT(MM_Map);
 677 //EXPORT(MM_Unmap);
 678 EXPORT(MM_MapHWPage);
 679 EXPORT(MM_UnmapHWPage);