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
 163         Log("Directory Entries:");
 164         for(page = Start >> 10;
 165                 page < (End >> 10)+1;
 166                 page ++)
 167         {
 168                 if(gaPageDir[page])
 169                 {
 170                         Log(" 0x%08x-0x%08x :: 0x%08x",
 171                                 page<<22, ((page+1)<<22)-1,
 172                                 gaPageDir[page]&~0xFFF
 173                                 );
 174                 }
 175         }
 176
 177         Log("Table Entries:");
 178         for(page = Start, curPos = Start<<12;
 179                 page < End;
 180                 curPos += 0x1000, page++)
 181         {
 182                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 183                 ||  !(gaPageTable[page] & PF_PRESENT)
 184                 ||  (gaPageTable[page] & MASK) != expected)
 185                 {
 186                         if(expected) {
 187                                 Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 188                                         rangeStart, curPos - 1,
 189                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 190                                         (expected & ~0xFFF) - 1,
 191                                         (expected & PF_PAGED ? "p" : "-"),
 192                                         (expected & PF_COW ? "C" : "-"),
 193                                         (expected & PF_USER ? "U" : "-"),
 194                                         (expected & PF_WRITE ? "W" : "-")
 195                                         );
 196                                 expected = 0;
 197                         }
 198                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 199                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 200
 201                         expected = (gaPageTable[page] & MASK);
 202                         rangeStart = curPos;
 203                 }
 204                 if(expected)    expected += 0x1000;
 205         }
 206
 207         if(expected) {
 208                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 209                         rangeStart, curPos - 1,
 210                         gaPageTable[rangeStart>>12] & ~0xFFF,
 211                         (expected & ~0xFFF) - 1,
 212                         (expected & PF_PAGED ? "p" : "-"),
 213                         (expected & PF_COW ? "C" : "-"),
 214                         (expected & PF_USER ? "U" : "-"),
 215                         (expected & PF_WRITE ? "W" : "-")
 216                         );
 217                 expected = 0;
 218         }
 219 }
 220
 221 /**
 222  * \fn tPAddr MM_Allocate(Uint VAddr)
 223  */
 224 tPAddr MM_Allocate(Uint VAddr)
 225 {
 226         tPAddr  paddr;
 227         // Check if the directory is mapped
 228         if( gaPageDir[ VAddr >> 22 ] == 0 )
 229         {
 230                 // Allocate directory
 231                 paddr = MM_AllocPhys();
 232                 if( paddr == 0 ) {
 233                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 234                         return 0;
 235                 }
 236                 // Map
 237                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 238                 // Mark as user
 239                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 240
 241                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 242                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 243         }
 244         // Check if the page is already allocated
 245         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 246                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 247                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 248         }
 249
 250         // Allocate
 251         paddr = MM_AllocPhys();
 252         if( paddr == 0 ) {
 253                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 254                         VAddr, __builtin_return_address(0));
 255                 return 0;
 256         }
 257         // Map
 258         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 259         // Mark as user
 260         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 261         // Invalidate Cache for address
 262         INVLPG( VAddr & ~0xFFF );
 263
 264         return paddr;
 265 }
 266
 267 /**
 268  * \fn void MM_Deallocate(Uint VAddr)
 269  */
 270 void MM_Deallocate(Uint VAddr)
 271 {
 272         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 273                 Warning("MM_Deallocate - Directory not mapped");
 274                 return;
 275         }
 276
 277         if(gaPageTable[ VAddr >> 12 ] == 0) {
 278                 Warning("MM_Deallocate - Page is not allocated");
 279                 return;
 280         }
 281
 282         // Dereference page
 283         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 284         // Clear page
 285         gaPageTable[ VAddr >> 12 ] = 0;
 286 }
 287
 288 /**
 289  * \fn tPAddr MM_GetPhysAddr(Uint Addr)
 290  * \brief Checks if the passed address is accesable
 291  */
 292 tPAddr MM_GetPhysAddr(Uint Addr)
 293 {
 294         if( !(gaPageDir[Addr >> 22] & 1) )
 295                 return 0;
 296         if( !(gaPageTable[Addr >> 12] & 1) )
 297                 return 0;
 298         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 299 }
 300
 301 /**
 302  * \fn void MM_SetCR3(Uint CR3)
 303  * \brief Sets the current process space
 304  */
 305 void MM_SetCR3(Uint CR3)
 306 {
 307         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 308 }
 309
 310 /**
 311  * \fn int MM_Map(Uint VAddr, tPAddr PAddr)
 312  * \brief Map a physical page to a virtual one
 313  */
 314 int MM_Map(Uint VAddr, tPAddr PAddr)
 315 {
 316         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 317         // Sanity check
 318         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 319                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 320                 //LEAVE('i', 0);
 321                 return 0;
 322         }
 323
 324         // Align addresses
 325         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 326
 327         // Check if the directory is mapped
 328         if( gaPageDir[ VAddr >> 22 ] == 0 )
 329         {
 330                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 331
 332                 // Mark as user
 333                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 334
 335                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 336                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 337         }
 338         // Check if the page is already allocated
 339         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 340                 Warning("MM_Map - Allocating to used address");
 341                 //LEAVE('i', 0);
 342                 return 0;
 343         }
 344
 345         // Map
 346         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 347         // Mark as user
 348         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 349
 350         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 351         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 352
 353         // Reference
 354         MM_RefPhys( PAddr );
 355
 356         //LOG("INVLPG( 0x%x )", VAddr);
 357         INVLPG( VAddr );
 358
 359         //LEAVE('i', 1);
 360         return 1;
 361 }
 362
 363 /**
 364  * \fn Uint MM_ClearUser()
 365  * \brief Clear user's address space
 366  */
 367 Uint MM_ClearUser()
 368 {
 369         Uint    i, j;
 370
 371         // Copy Directories
 372         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 373         {
 374                 // Check if directory is not allocated
 375                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 376                         gaPageDir[i] = 0;
 377                         continue;
 378                 }
 379
 380
 381                 for( j = 0; j < 1024; j ++ )
 382                 {
 383                         if( gaPageTable[i*1024+j] & 1 )
 384                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 385                         gaPageTable[i*1024+j] = 0;
 386                 }
 387
 388                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 389                 gaPageDir[i] = 0;
 390                 INVLPG( &gaPageTable[i*1024] );
 391         }
 392         INVLPG( gaPageDir );
 393
 394         return *gaPageCR3;
 395 }
 396
 397 /**
 398  * \fn Uint MM_Clone()
 399  * \brief Clone the current address space
 400  */
 401 Uint MM_Clone()
 402 {
 403         Uint    i, j;
 404         Uint    page = 0;
 405         Uint    kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 406         void    *tmp;
 407
 408         //ENTER("");
 409
 410         // Create Directory Table
 411         *gTmpCR3 = MM_AllocPhys() | 3;
 412         INVLPG( gaTmpDir );
 413         //LOG("Allocated Directory (%x)", *gTmpCR3);
 414         memsetd( gaTmpDir, 0, 1024 );
 415
 416         // Copy Tables
 417         for(i=0;i<768;i++)
 418         {
 419                 // Check if table is allocated
 420                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 421                         gaTmpDir[i] = 0;
 422                         page += 1024;
 423                         continue;
 424                 }
 425
 426                 // Allocate new table
 427                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 428                 INVLPG( &gaTmpTable[page] );
 429                 // Fill
 430                 for( j = 0; j < 1024; j ++, page++ )
 431                 {
 432                         if( !(gaPageTable[page] & PF_PRESENT) ) {
 433                                 gaTmpTable[page] = 0;
 434                                 continue;
 435                         }
 436
 437                         // Refrence old page
 438                         MM_RefPhys( gaPageTable[page] & ~0xFFF );
 439                         // Add to new table
 440                         if(gaPageTable[page] & PF_WRITE) {
 441                                 gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 442                                 gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 443                                 INVLPG( page << 12 );
 444                         }
 445                         else
 446                                 gaTmpTable[page] = gaPageTable[page];
 447                 }
 448         }
 449
 450         // Map in kernel tables (and make fractal mapping)
 451         for( i = 768; i < 1024; i ++ )
 452         {
 453                 // Fractal
 454                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 455                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 456                         continue;
 457                 }
 458
 459                 if( gaPageDir[i] == 0 ) {
 460                         gaTmpDir[i] = 0;
 461                         continue;
 462                 }
 463
 464                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 465                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 466                 gaTmpDir[i] = gaPageDir[i];
 467         }
 468
 469         // Allocate kernel stack
 470         for(i = KERNEL_STACKS >> 22;
 471                 i < KERNEL_STACK_END >> 22;
 472                 i ++ )
 473         {
 474                 // Check if directory is allocated
 475                 if( (gaPageDir[i] & 1) == 0 ) {
 476                         gaTmpDir[i] = 0;
 477                         continue;
 478                 }
 479
 480                 // We don't care about other kernel stacks, just the current one
 481                 if( i != kStackBase >> 22 ) {
 482                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 483                         gaTmpDir[i] = 0;
 484                         continue;
 485                 }
 486
 487                 // Create a copy
 488                 gaTmpDir[i] = MM_AllocPhys() | 3;
 489                 INVLPG( &gaTmpTable[i*1024] );
 490                 for( j = 0; j < 1024; j ++ )
 491                 {
 492                         // Is the page allocated? If not, skip
 493                         if( !(gaPageTable[i*1024+j] & 1) ) {
 494                                 gaTmpTable[i*1024+j] = 0;
 495                                 continue;
 496                         }
 497
 498                         // We don't care about other kernel stacks
 499                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 500                                 gaTmpTable[i*1024+j] = 0;
 501                                 continue;
 502                         }
 503
 504                         // Allocate page
 505                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 506
 507                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 508
 509                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 510                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 511                         MM_FreeTemp( (Uint)tmp );
 512                 }
 513         }
 514
 515         //LEAVE('x', *gTmpCR3 & ~0xFFF);
 516         return *gTmpCR3 & ~0xFFF;
 517 }
 518
 519 /**
 520  * \fn Uint MM_NewKStack()
 521  * \brief Create a new kernel stack
 522  */
 523 Uint MM_NewKStack()
 524 {
 525         Uint    base = KERNEL_STACKS;
 526         Uint    i;
 527         for(;base<KERNEL_STACK_END;base+=KERNEL_STACK_SIZE)
 528         {
 529                 if(MM_GetPhysAddr(base) != 0)   continue;
 530                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 531                         MM_Allocate(base+i);
 532                 }
 533                 return base+KERNEL_STACK_SIZE;
 534         }
 535         Warning("MM_NewKStack - No address space left\n");
 536         return 0;
 537 }
 538
 539 /**
 540  * \fn void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 541  * \brief Sets the flags on a page
 542  */
 543 void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 544 {
 545         tPAddr  *ent;
 546         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 547         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 548
 549         ent = &gaPageTable[VAddr >> 12];
 550
 551         // Read-Only
 552         if( Mask & MM_PFLAG_RO )
 553         {
 554                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 555                 else    *ent |= PF_WRITE;
 556         }
 557
 558         // Kernel
 559         if( Mask & MM_PFLAG_KERNEL )
 560         {
 561                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 562                 else    *ent |= PF_USER;
 563         }
 564
 565         // Copy-On-Write
 566         if( Mask & MM_PFLAG_COW )
 567         {
 568                 if( Flags & MM_PFLAG_COW ) {
 569                         *ent &= ~PF_WRITE;
 570                         *ent |= PF_COW;
 571                 }
 572                 else {
 573                         *ent &= ~PF_COW;
 574                         *ent |= PF_WRITE;
 575                 }
 576         }
 577 }
 578
 579 /**
 580  * \fn tPAddr MM_DuplicatePage(Uint VAddr)
 581  * \brief Duplicates a virtual page to a physical one
 582  */
 583 tPAddr MM_DuplicatePage(Uint VAddr)
 584 {
 585         tPAddr  ret;
 586         Uint    temp;
 587          int    wasRO = 0;
 588
 589         // Check if mapped
 590         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 591         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 592
 593         // Page Align
 594         VAddr &= ~0xFFF;
 595
 596         // Allocate new page
 597         ret = MM_AllocPhys();
 598
 599         // Write-lock the page (to keep data constistent), saving its R/W state
 600         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 601         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 602         INVLPG( VAddr );
 603
 604         // Copy Data
 605         temp = MM_MapTemp(ret);
 606         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 607         MM_FreeTemp(temp);
 608
 609         // Restore Writeable status
 610         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 611         INVLPG(VAddr);
 612
 613         return ret;
 614 }
 615
 616 /**
 617  * \fn Uint MM_MapTemp(tPAddr PAddr)
 618  * \brief Create a temporary memory mapping
 619  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 620  */
 621 Uint MM_MapTemp(tPAddr PAddr)
 622 {
 623          int    i;
 624
 625         //ENTER("XPAddr", PAddr);
 626
 627         PAddr &= ~0xFFF;
 628
 629         //LOG("gilTempMappings = %i", gilTempMappings);
 630
 631         for(;;)
 632         {
 633                 LOCK( &gilTempMappings );
 634
 635                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 636                 {
 637                         // Check if page used
 638                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 639                         // Mark as used
 640                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 641                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 642                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 643                         RELEASE( &gilTempMappings );
 644                         return TEMP_MAP_ADDR + (i << 12);
 645                 }
 646                 RELEASE( &gilTempMappings );
 647                 Threads_Yield();
 648         }
 649 }
 650
 651 /**
 652  * \fn void MM_FreeTemp(Uint PAddr)
 653  * \brief Free's a temp mapping
 654  */
 655 void MM_FreeTemp(Uint VAddr)
 656 {
 657          int    i = VAddr >> 12;
 658         //ENTER("xVAddr", VAddr);
 659
 660         if(i >= (TEMP_MAP_ADDR >> 12))
 661                 gaPageTable[ i ] = 0;
 662
 663         //LEAVE('-');
 664 }
 665
 666 /**
 667  * \fn Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 668  * \brief Allocates a contigous number of pages
 669  */
 670 Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 671 {
 672          int    i, j;
 673
 674         PAddr &= ~0xFFF;
 675
 676         // Scan List
 677         for( i = 0; i < NUM_HW_PAGES; i ++ )
 678         {
 679                 // Check if addr used
 680                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 681                         continue;
 682
 683                 // Check possible region
 684                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 685                 {
 686                         // If there is an allocated page in the region we are testing, break
 687                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 688                 }
 689                 // Is it all free?
 690                 if( j == Number )
 691                 {
 692                         // Allocate
 693                         for( j = 0; j < Number; j++ ) {
 694                                 MM_RefPhys( PAddr + (j<<12) );
 695                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 696                         }
 697                         return HW_MAP_ADDR + (i<<12);
 698                 }
 699         }
 700         // If we don't find any, return NULL
 701         return 0;
 702 }
 703
 704 /**
 705  * \fn void MM_UnmapHWPage(Uint VAddr, Uint Number)
 706  * \brief Unmap a hardware page
 707  */
 708 void MM_UnmapHWPage(Uint VAddr, Uint Number)
 709 {
 710          int    i, j;
 711         // Sanity Check
 712         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 713
 714         i = VAddr >> 12;
 715
 716         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 717
 718         for( j = 0; j < Number; j++ )
 719         {
 720                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 721                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 722         }
 723
 724         RELEASE( &gilTempMappings );
 725 }
 726
 727 // --- EXPORTS ---
 728 EXPORT(MM_GetPhysAddr);
 729 EXPORT(MM_Map);
 730 //EXPORT(MM_Unmap);
 731 EXPORT(MM_MapHWPage);
 732 EXPORT(MM_UnmapHWPage);