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 >> 22;
 165                 page < End >> 22;
 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         }
 390
 391
 392         return *gTmpCR3;
 393 }
 394
 395 /**
 396  * \fn Uint MM_Clone()
 397  * \brief Clone the current address space
 398  */
 399 Uint MM_Clone()
 400 {
 401         Uint    i, j;
 402         Uint    page = 0;
 403         Uint    kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 404         void    *tmp;
 405
 406         //ENTER("");
 407
 408         // Create Directory Table
 409         *gTmpCR3 = MM_AllocPhys() | 3;
 410         INVLPG( gaTmpDir );
 411         //LOG("Allocated Directory (%x)", *gTmpCR3);
 412         memsetd( gaTmpDir, 0, 1024 );
 413
 414         // Copy Tables
 415         for(i=0;i<768;i++)
 416         {
 417                 // Check if table is allocated
 418                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 419                         gaTmpDir[i] = 0;
 420                         page += 1024;
 421                         continue;
 422                 }
 423
 424                 // Allocate new table
 425                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 426                 INVLPG( &gaTmpTable[page] );
 427                 // Fill
 428                 for( j = 0; j < 1024; j ++, page++ )
 429                 {
 430                         if( !(gaPageTable[page] & PF_PRESENT) ) {
 431                                 gaTmpTable[page] = 0;
 432                                 continue;
 433                         }
 434
 435                         // Refrence old page
 436                         MM_RefPhys( gaPageTable[page] & ~0xFFF );
 437                         // Add to new table
 438                         if(gaPageTable[page] & PF_WRITE) {
 439                                 gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 440                                 gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 441                                 INVLPG( page << 12 );
 442                         }
 443                         else
 444                                 gaTmpTable[page] = gaPageTable[page];
 445                 }
 446         }
 447
 448         // Map in kernel tables (and make fractal mapping)
 449         for( i = 768; i < 1024; i ++ )
 450         {
 451                 // Fractal
 452                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 453                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 454                         continue;
 455                 }
 456
 457                 if( gaPageDir[i] == 0 ) {
 458                         gaTmpDir[i] = 0;
 459                         continue;
 460                 }
 461
 462                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 463                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 464                 gaTmpDir[i] = gaPageDir[i];
 465         }
 466
 467         // Allocate kernel stack
 468         for(i = KERNEL_STACKS >> 22;
 469                 i < KERNEL_STACK_END >> 22;
 470                 i ++ )
 471         {
 472                 // Check if directory is allocated
 473                 if( (gaPageDir[i] & 1) == 0 ) {
 474                         gaTmpDir[i] = 0;
 475                         continue;
 476                 }
 477
 478                 // We don't care about other kernel stacks, just the current one
 479                 if( i != kStackBase >> 22 ) {
 480                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 481                         gaTmpDir[i] = 0;
 482                         continue;
 483                 }
 484
 485                 // Create a copy
 486                 gaTmpDir[i] = MM_AllocPhys() | 3;
 487                 INVLPG( &gaTmpTable[i*1024] );
 488                 for( j = 0; j < 1024; j ++ )
 489                 {
 490                         // Is the page allocated? If not, skip
 491                         if( !(gaPageTable[i*1024+j] & 1) ) {
 492                                 gaTmpTable[i*1024+j] = 0;
 493                                 continue;
 494                         }
 495
 496                         // We don't care about other kernel stacks
 497                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 498                                 gaTmpTable[i*1024+j] = 0;
 499                                 continue;
 500                         }
 501
 502                         // Allocate page
 503                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 504
 505                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 506
 507                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 508                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 509                         MM_FreeTemp( (Uint)tmp );
 510                 }
 511         }
 512
 513         //LEAVE('x', *gTmpCR3 & ~0xFFF);
 514         return *gTmpCR3 & ~0xFFF;
 515 }
 516
 517 /**
 518  * \fn Uint MM_NewKStack()
 519  * \brief Create a new kernel stack
 520  */
 521 Uint MM_NewKStack()
 522 {
 523         Uint    base = KERNEL_STACKS;
 524         Uint    i;
 525         for(;base<KERNEL_STACK_END;base+=KERNEL_STACK_SIZE)
 526         {
 527                 if(MM_GetPhysAddr(base) != 0)   continue;
 528                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 529                         MM_Allocate(base+i);
 530                 }
 531                 return base+KERNEL_STACK_SIZE;
 532         }
 533         Warning("MM_NewKStack - No address space left\n");
 534         return 0;
 535 }
 536
 537 /**
 538  * \fn void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 539  * \brief Sets the flags on a page
 540  */
 541 void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 542 {
 543         tPAddr  *ent;
 544         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 545         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 546
 547         ent = &gaPageTable[VAddr >> 12];
 548
 549         // Read-Only
 550         if( Mask & MM_PFLAG_RO )
 551         {
 552                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 553                 else    *ent |= PF_WRITE;
 554         }
 555
 556         // Kernel
 557         if( Mask & MM_PFLAG_KERNEL )
 558         {
 559                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 560                 else    *ent |= PF_USER;
 561         }
 562
 563         // Copy-On-Write
 564         if( Mask & MM_PFLAG_COW )
 565         {
 566                 if( Flags & MM_PFLAG_COW ) {
 567                         *ent &= ~PF_WRITE;
 568                         *ent |= PF_COW;
 569                 }
 570                 else {
 571                         *ent &= ~PF_COW;
 572                         *ent |= PF_WRITE;
 573                 }
 574         }
 575 }
 576
 577 /**
 578  * \fn tPAddr MM_DuplicatePage(Uint VAddr)
 579  * \brief Duplicates a virtual page to a physical one
 580  */
 581 tPAddr MM_DuplicatePage(Uint VAddr)
 582 {
 583         tPAddr  ret;
 584         Uint    temp;
 585          int    wasRO = 0;
 586
 587         // Check if mapped
 588         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 589         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 590
 591         // Page Align
 592         VAddr &= ~0xFFF;
 593
 594         // Allocate new page
 595         ret = MM_AllocPhys();
 596
 597         // Write-lock the page (to keep data constistent), saving its R/W state
 598         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 599         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 600         INVLPG( VAddr );
 601
 602         // Copy Data
 603         temp = MM_MapTemp(ret);
 604         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 605         MM_FreeTemp(temp);
 606
 607         // Restore Writeable status
 608         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 609         INVLPG(VAddr);
 610
 611         return ret;
 612 }
 613
 614 /**
 615  * \fn Uint MM_MapTemp(tPAddr PAddr)
 616  * \brief Create a temporary memory mapping
 617  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 618  */
 619 Uint MM_MapTemp(tPAddr PAddr)
 620 {
 621          int    i;
 622
 623         //ENTER("XPAddr", PAddr);
 624
 625         PAddr &= ~0xFFF;
 626
 627         //LOG("gilTempMappings = %i", gilTempMappings);
 628
 629         for(;;)
 630         {
 631                 LOCK( &gilTempMappings );
 632
 633                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 634                 {
 635                         // Check if page used
 636                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 637                         // Mark as used
 638                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 639                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 640                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 641                         RELEASE( &gilTempMappings );
 642                         return TEMP_MAP_ADDR + (i << 12);
 643                 }
 644                 RELEASE( &gilTempMappings );
 645                 Threads_Yield();
 646         }
 647 }
 648
 649 /**
 650  * \fn void MM_FreeTemp(Uint PAddr)
 651  * \brief Free's a temp mapping
 652  */
 653 void MM_FreeTemp(Uint VAddr)
 654 {
 655          int    i = VAddr >> 12;
 656         //ENTER("xVAddr", VAddr);
 657
 658         if(i >= (TEMP_MAP_ADDR >> 12))
 659                 gaPageTable[ i ] = 0;
 660
 661         //LEAVE('-');
 662 }
 663
 664 /**
 665  * \fn Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 666  * \brief Allocates a contigous number of pages
 667  */
 668 Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 669 {
 670          int    i, j;
 671
 672         PAddr &= ~0xFFF;
 673
 674         // Scan List
 675         for( i = 0; i < NUM_HW_PAGES; i ++ )
 676         {
 677                 // Check if addr used
 678                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 679                         continue;
 680
 681                 // Check possible region
 682                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 683                 {
 684                         // If there is an allocated page in the region we are testing, break
 685                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 686                 }
 687                 // Is it all free?
 688                 if( j == Number )
 689                 {
 690                         // Allocate
 691                         for( j = 0; j < Number; j++ ) {
 692                                 MM_RefPhys( PAddr + (j<<12) );
 693                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 694                         }
 695                         return HW_MAP_ADDR + (i<<12);
 696                 }
 697         }
 698         // If we don't find any, return NULL
 699         return 0;
 700 }
 701
 702 /**
 703  * \fn void MM_UnmapHWPage(Uint VAddr, Uint Number)
 704  * \brief Unmap a hardware page
 705  */
 706 void MM_UnmapHWPage(Uint VAddr, Uint Number)
 707 {
 708          int    i, j;
 709         // Sanity Check
 710         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 711
 712         i = VAddr >> 12;
 713
 714         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 715
 716         for( j = 0; j < Number; j++ )
 717         {
 718                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 719                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 720         }
 721
 722         RELEASE( &gilTempMappings );
 723 }
 724
 725 // --- EXPORTS ---
 726 EXPORT(MM_GetPhysAddr);
 727 EXPORT(MM_Map);
 728 //EXPORT(MM_Unmap);
 729 EXPORT(MM_MapHWPage);
 730 EXPORT(MM_UnmapHWPage);