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   0
  13 #define SANITY  1
  14 #include <acess.h>
  15 #include <mm_virt.h>
  16 #include <mm_phys.h>
  17 #include <proc.h>
  18
  19 #if USE_PAE
  20 # define TAB    21
  21 # define DIR    30
  22 #else
  23 # define TAB    22
  24 #endif
  25
  26 #define KERNEL_STACKS           0xF0000000
  27 #define KERNEL_STACK_SIZE       0x00008000
  28 #define KERNEL_STACKS_END       0xFC000000
  29 #define WORKER_STACKS           0x00100000      // Thread0 Only!
  30 #define WORKER_STACK_SIZE       KERNEL_STACK_SIZE
  31 #define WORKER_STACKS_END       0xB0000000
  32 #define NUM_WORKER_STACKS       ((WORKER_STACKS_END-WORKER_STACKS)/WORKER_STACK_SIZE)
  33
  34 #define PAE_PAGE_TABLE_ADDR     0xFC000000      // 16 MiB
  35 #define PAE_PAGE_DIR_ADDR       0xFCFC0000      // 16 KiB
  36 #define PAE_PAGE_PDPT_ADDR      0xFCFC3F00      // 32 bytes
  37 #define PAE_TMP_PDPT_ADDR       0xFCFC3F20      // 32 bytes
  38 #define PAE_TMP_DIR_ADDR        0xFCFE0000      // 16 KiB
  39 #define PAE_TMP_TABLE_ADDR      0xFD000000      // 16 MiB
  40
  41 #define PAGE_TABLE_ADDR 0xFC000000
  42 #define PAGE_DIR_ADDR   0xFC3F0000
  43 #define PAGE_CR3_ADDR   0xFC3F0FC0
  44 #define TMP_CR3_ADDR    0xFC3F0FC4      // Part of core instead of temp
  45 #define TMP_DIR_ADDR    0xFC3F1000      // Same
  46 #define TMP_TABLE_ADDR  0xFC400000
  47
  48 #define HW_MAP_ADDR             0xFE000000
  49 #define HW_MAP_MAX              0xFFEF0000
  50 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  51 #define TEMP_MAP_ADDR   0xFFEF0000      // Allows 16 "temp" pages
  52 #define NUM_TEMP_PAGES  16
  53 #define LAST_BLOCK_ADDR 0xFFFF0000      // Free space for kernel provided user code/ *(-1) protection
  54
  55 #define PF_PRESENT      0x1
  56 #define PF_WRITE        0x2
  57 #define PF_USER         0x4
  58 #define PF_GLOBAL       0x80
  59 #define PF_COW          0x200
  60 #define PF_NOPAGE       0x400
  61
  62 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  63
  64 #if USE_PAE
  65 typedef Uint64  tTabEnt;
  66 #else
  67 typedef Uint32  tTabEnt;
  68 #endif
  69
  70 // === IMPORTS ===
  71 extern void     _UsertextEnd, _UsertextBase;
  72 extern Uint32   gaInitPageDir[1024];
  73 extern Uint32   gaInitPageTable[1024];
  74 extern void     Threads_SegFault(tVAddr Addr);
  75 extern void     Error_Backtrace(Uint eip, Uint ebp);
  76
  77 // === PROTOTYPES ===
  78 void    MM_PreinitVirtual(void);
  79 void    MM_InstallVirtual(void);
  80 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  81 void    MM_DumpTables(tVAddr Start, tVAddr End);
  82 tVAddr  MM_ClearUser(void);
  83 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  84
  85 // === GLOBALS ===
  86 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  87 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  88 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  89 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  90 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  91 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  92
  93 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  94 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  95 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  96 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  97 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  98 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  99  int    gbUsePAE = 0;
 100 tMutex  glTempMappings;
 101 tMutex  glTempFractal;
 102 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
 103  int    giLastUsedWorker = 0;
 104 struct sPageInfo {
 105         void    *Node;
 106         tVAddr  Base;
 107         Uint64  Offset;
 108          int    Length;
 109          int    Flags;
 110 }       *gaMappedRegions;       // sizeof = 24 bytes
 111
 112 // === CODE ===
 113 /**
 114  * \fn void MM_PreinitVirtual(void)
 115  * \brief Maps the fractal mappings
 116  */
 117 void MM_PreinitVirtual(void)
 118 {
 119         #if USE_PAE
 120         gaInitPageDir[ ((PAGE_TABLE_ADDR >> TAB)-3*512+3)*2 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 121         #else
 122         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 123         #endif
 124         INVLPG( PAGE_TABLE_ADDR );
 125 }
 126
 127 /**
 128  * \fn void MM_InstallVirtual(void)
 129  * \brief Sets up the constant page mappings
 130  */
 131 void MM_InstallVirtual(void)
 132 {
 133          int    i;
 134
 135         #if USE_PAE
 136         // --- Pre-Allocate kernel tables
 137         for( i = KERNEL_BASE >> TAB; i < 1024*4; i ++ )
 138         {
 139                 if( gaPAE_PageDir[ i ] )        continue;
 140
 141                 // Skip stack tables, they are process unique
 142                 if( i > KERNEL_STACKS >> TAB && i < KERNEL_STACKS_END >> TAB) {
 143                         gaPAE_PageDir[ i ] = 0;
 144                         continue;
 145                 }
 146                 // Preallocate table
 147                 gaPAE_PageDir[ i ] = MM_AllocPhys() | 3;
 148                 INVLPG( &gaPAE_PageTable[i*512] );
 149                 memset( &gaPAE_PageTable[i*512], 0, 0x1000 );
 150         }
 151         #else
 152         // --- Pre-Allocate kernel tables
 153         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 154         {
 155                 if( gaPageDir[ i ] )    continue;
 156                 // Skip stack tables, they are process unique
 157                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 158                         gaPageDir[ i ] = 0;
 159                         continue;
 160                 }
 161                 // Preallocate table
 162                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 163                 INVLPG( &gaPageTable[i*1024] );
 164                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 165         }
 166         #endif
 167
 168         // Unset kernel on the User Text pages
 169         for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
 170                 MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
 171         }
 172 }
 173
 174 /**
 175  * \brief Cleans up the SMP required mappings
 176  */
 177 void MM_FinishVirtualInit(void)
 178 {
 179         #if USE_PAE
 180         gaInitPDPT[ 0 ] = 0;
 181         #else
 182         gaInitPageDir[ 0 ] = 0;
 183         #endif
 184 }
 185
 186 /**
 187  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 188  * \brief Called on a page fault
 189  */
 190 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 191 {
 192         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 193
 194         // -- Check for COW --
 195         if( gaPageDir  [Addr>>22] & PF_PRESENT  && gaPageTable[Addr>>12] & PF_PRESENT
 196          && gaPageTable[Addr>>12] & PF_COW )
 197         {
 198                 tPAddr  paddr;
 199                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 200                 {
 201                         gaPageTable[Addr>>12] &= ~PF_COW;
 202                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 203                 }
 204                 else
 205                 {
 206                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 207                         paddr = MM_DuplicatePage( Addr );
 208                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 209                         gaPageTable[Addr>>12] &= PF_USER;
 210                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 211                 }
 212
 213                 INVLPG( Addr & ~0xFFF );
 214                 return;
 215         }
 216
 217         // If it was a user, tell the thread handler
 218         if(ErrorCode & 4) {
 219                 Warning("%s %s %s memory%s",
 220                         (ErrorCode&4?"User":"Kernel"),
 221                         (ErrorCode&2?"write to":"read from"),
 222                         (ErrorCode&1?"bad/locked":"non-present"),
 223                         (ErrorCode&16?" (Instruction Fetch)":"")
 224                         );
 225                 Warning("User Pagefault: Instruction at %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 226                 __asm__ __volatile__ ("sti");   // Restart IRQs
 227                 #if 1
 228                 Error_Backtrace(Regs->eip, Regs->ebp);
 229                 #endif
 230                 Threads_SegFault(Addr);
 231                 return ;
 232         }
 233
 234         Debug_KernelPanic();
 235
 236         // -- Check Error Code --
 237         if(ErrorCode & 8)
 238                 Warning("Reserved Bits Trashed!");
 239         else
 240         {
 241                 Warning("%s %s %s memory%s",
 242                         (ErrorCode&4?"User":"Kernel"),
 243                         (ErrorCode&2?"write to":"read from"),
 244                         (ErrorCode&1?"bad/locked":"non-present"),
 245                         (ErrorCode&16?" (Instruction Fetch)":"")
 246                         );
 247         }
 248
 249         Log("Code at %p accessed %p", Regs->eip, Addr);
 250         // Print Stack Backtrace
 251         Error_Backtrace(Regs->eip, Regs->ebp);
 252
 253         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 254         if( gaPageDir[Addr>>22] & PF_PRESENT )
 255                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 256
 257         //MM_DumpTables(0, -1);
 258
 259         // Register Dump
 260         Log("EAX %08x ECX %08x EDX %08x EBX %08x", Regs->eax, Regs->ecx, Regs->edx, Regs->ebx);
 261         Log("ESP %08x EBP %08x ESI %08x EDI %08x", Regs->esp, Regs->ebp, Regs->esi, Regs->edi);
 262         //Log("SS:ESP %04x:%08x", Regs->ss, Regs->esp);
 263         Log("CS:EIP %04x:%08x", Regs->cs, Regs->eip);
 264         Log("DS %04x ES %04x FS %04x GS %04x", Regs->ds, Regs->es, Regs->fs, Regs->gs);
 265         {
 266                 Uint    dr0, dr1;
 267                 __ASM__ ("mov %%dr0, %0":"=r"(dr0):);
 268                 __ASM__ ("mov %%dr1, %0":"=r"(dr1):);
 269                 Log("DR0 %08x DR1 %08x", dr0, dr1);
 270         }
 271
 272         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 273 }
 274
 275 /**
 276  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 277  * \brief Dumps the layout of the page tables
 278  */
 279 void MM_DumpTables(tVAddr Start, tVAddr End)
 280 {
 281         tVAddr  rangeStart = 0;
 282         tPAddr  expected = 0;
 283         tVAddr  curPos;
 284         Uint    page;
 285         const tPAddr    MASK = ~0xF78;
 286
 287         Start >>= 12;   End >>= 12;
 288
 289         #if 0
 290         Log("Directory Entries:");
 291         for(page = Start >> 10;
 292                 page < (End >> 10)+1;
 293                 page ++)
 294         {
 295                 if(gaPageDir[page])
 296                 {
 297                         Log(" 0x%08x-0x%08x :: 0x%08x",
 298                                 page<<22, ((page+1)<<22)-1,
 299                                 gaPageDir[page]&~0xFFF
 300                                 );
 301                 }
 302         }
 303         #endif
 304
 305         Log("Table Entries:");
 306         for(page = Start, curPos = Start<<12;
 307                 page < End;
 308                 curPos += 0x1000, page++)
 309         {
 310                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 311                 ||  !(gaPageTable[page] & PF_PRESENT)
 312                 ||  (gaPageTable[page] & MASK) != expected)
 313                 {
 314                         if(expected) {
 315                                 Log(" 0x%08x => 0x%08x - 0x%08x (%s%s%s%s%s)",
 316                                         rangeStart,
 317                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 318                                         curPos - rangeStart,
 319                                         (expected & PF_NOPAGE ? "P" : "-"),
 320                                         (expected & PF_COW ? "C" : "-"),
 321                                         (expected & PF_GLOBAL ? "G" : "-"),
 322                                         (expected & PF_USER ? "U" : "-"),
 323                                         (expected & PF_WRITE ? "W" : "-"),
 324                                         gaPageTable[page] & MASK, expected
 325                                         );
 326                                 expected = 0;
 327                         }
 328                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 329                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 330
 331                         expected = (gaPageTable[page] & MASK);
 332                         rangeStart = curPos;
 333                 }
 334                 if(expected)    expected += 0x1000;
 335         }
 336
 337         if(expected) {
 338                 Log("0x%08x => 0x%08x - 0x%08x (%s%s%s%s)",
 339                         rangeStart,
 340                         gaPageTable[rangeStart>>12] & ~0xFFF,
 341                         curPos - rangeStart,
 342                         (expected & PF_NOPAGE ? "p" : "-"),
 343                         (expected & PF_COW ? "C" : "-"),
 344                         (expected & PF_USER ? "U" : "-"),
 345                         (expected & PF_WRITE ? "W" : "-")
 346                         );
 347                 expected = 0;
 348         }
 349 }
 350
 351 /**
 352  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 353  */
 354 tPAddr MM_Allocate(tVAddr VAddr)
 355 {
 356         tPAddr  paddr;
 357         //ENTER("xVAddr", VAddr);
 358         //__asm__ __volatile__ ("xchg %bx,%bx");
 359         // Check if the directory is mapped
 360         if( gaPageDir[ VAddr >> 22 ] == 0 )
 361         {
 362                 // Allocate directory
 363                 paddr = MM_AllocPhys();
 364                 if( paddr == 0 ) {
 365                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 366                         //LEAVE('i',0);
 367                         return 0;
 368                 }
 369                 // Map and mark as user (if needed)
 370                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 371                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 372
 373                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 374                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 375         }
 376         // Check if the page is already allocated
 377         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 378                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 379                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 380                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 381         }
 382
 383         // Allocate
 384         paddr = MM_AllocPhys();
 385         //LOG("paddr = 0x%llx", paddr);
 386         if( paddr == 0 ) {
 387                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 388                         VAddr, __builtin_return_address(0));
 389                 //LEAVE('i',0);
 390                 return 0;
 391         }
 392         // Map
 393         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 394         // Mark as user
 395         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 396         // Invalidate Cache for address
 397         INVLPG( VAddr & ~0xFFF );
 398
 399         //LEAVE('X', paddr);
 400         return paddr;
 401 }
 402
 403 /**
 404  * \fn void MM_Deallocate(tVAddr VAddr)
 405  */
 406 void MM_Deallocate(tVAddr VAddr)
 407 {
 408         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 409                 Warning("MM_Deallocate - Directory not mapped");
 410                 return;
 411         }
 412
 413         if(gaPageTable[ VAddr >> 12 ] == 0) {
 414                 Warning("MM_Deallocate - Page is not allocated");
 415                 return;
 416         }
 417
 418         // Dereference page
 419         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 420         // Clear page
 421         gaPageTable[ VAddr >> 12 ] = 0;
 422 }
 423
 424 /**
 425  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 426  * \brief Checks if the passed address is accesable
 427  */
 428 tPAddr MM_GetPhysAddr(tVAddr Addr)
 429 {
 430         if( !(gaPageDir[Addr >> 22] & 1) )
 431                 return 0;
 432         if( !(gaPageTable[Addr >> 12] & 1) )
 433                 return 0;
 434         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 435 }
 436
 437 /**
 438  * \fn void MM_SetCR3(Uint CR3)
 439  * \brief Sets the current process space
 440  */
 441 void MM_SetCR3(Uint CR3)
 442 {
 443         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 444 }
 445
 446 /**
 447  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 448  * \brief Map a physical page to a virtual one
 449  */
 450 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 451 {
 452         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 453         // Sanity check
 454         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 455                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 456                 //LEAVE('i', 0);
 457                 return 0;
 458         }
 459
 460         // Align addresses
 461         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 462
 463         // Check if the directory is mapped
 464         if( gaPageDir[ VAddr >> 22 ] == 0 )
 465         {
 466                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 467
 468                 // Mark as user
 469                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 470
 471                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 472                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 473         }
 474         // Check if the page is already allocated
 475         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 476                 Warning("MM_Map - Allocating to used address");
 477                 //LEAVE('i', 0);
 478                 return 0;
 479         }
 480
 481         // Map
 482         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 483         // Mark as user
 484         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 485
 486         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 487         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 488
 489         // Reference
 490         MM_RefPhys( PAddr );
 491
 492         //LOG("INVLPG( 0x%x )", VAddr);
 493         INVLPG( VAddr );
 494
 495         //LEAVE('i', 1);
 496         return 1;
 497 }
 498
 499 /**
 500  * \fn tVAddr MM_ClearUser()
 501  * \brief Clear user's address space
 502  */
 503 tVAddr MM_ClearUser(void)
 504 {
 505         Uint    i, j;
 506
 507         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 508         {
 509                 // Check if directory is not allocated
 510                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 511                         gaPageDir[i] = 0;
 512                         continue;
 513                 }
 514
 515                 // Deallocate tables
 516                 for( j = 0; j < 1024; j ++ )
 517                 {
 518                         if( gaPageTable[i*1024+j] & 1 )
 519                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 520                         gaPageTable[i*1024+j] = 0;
 521                 }
 522
 523                 // Deallocate directory
 524                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 525                 gaPageDir[i] = 0;
 526                 INVLPG( &gaPageTable[i*1024] );
 527         }
 528         INVLPG( gaPageDir );
 529
 530         return *gpPageCR3;
 531 }
 532
 533 /**
 534  * \fn tPAddr MM_Clone(void)
 535  * \brief Clone the current address space
 536  */
 537 tPAddr MM_Clone(void)
 538 {
 539         Uint    i, j;
 540         tVAddr  ret;
 541         Uint    page = 0;
 542         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 543         void    *tmp;
 544
 545         Mutex_Acquire( &glTempFractal );
 546
 547         // Create Directory Table
 548         *gpTmpCR3 = MM_AllocPhys() | 3;
 549         INVLPG( gaTmpDir );
 550         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 551         memsetd( gaTmpDir, 0, 1024 );
 552
 553         if( Threads_GetPID() != 0 )
 554         {
 555                 // Copy Tables
 556                 for( i = 0; i < 768; i ++)
 557                 {
 558                         // Check if table is allocated
 559                         if( !(gaPageDir[i] & PF_PRESENT) ) {
 560                                 gaTmpDir[i] = 0;
 561                                 page += 1024;
 562                                 continue;
 563                         }
 564
 565                         // Allocate new table
 566                         gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 567                         INVLPG( &gaTmpTable[page] );
 568                         // Fill
 569                         for( j = 0; j < 1024; j ++, page++ )
 570                         {
 571                                 if( !(gaPageTable[page] & PF_PRESENT) ) {
 572                                         gaTmpTable[page] = 0;
 573                                         continue;
 574                                 }
 575
 576                                 // Refrence old page
 577                                 MM_RefPhys( gaPageTable[page] & ~0xFFF );
 578                                 // Add to new table
 579                                 if(gaPageTable[page] & PF_WRITE) {
 580                                         gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 581                                         gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 582                                         INVLPG( page << 12 );
 583                                 }
 584                                 else
 585                                         gaTmpTable[page] = gaPageTable[page];
 586                         }
 587                 }
 588         }
 589
 590         // Map in kernel tables (and make fractal mapping)
 591         for( i = 768; i < 1024; i ++ )
 592         {
 593                 // Fractal
 594                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 595                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 596                         continue;
 597                 }
 598
 599                 if( gaPageDir[i] == 0 ) {
 600                         gaTmpDir[i] = 0;
 601                         continue;
 602                 }
 603
 604                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 605                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 606                 gaTmpDir[i] = gaPageDir[i];
 607         }
 608
 609         // Allocate kernel stack
 610         for(i = KERNEL_STACKS >> 22;
 611                 i < KERNEL_STACKS_END >> 22;
 612                 i ++ )
 613         {
 614                 // Check if directory is allocated
 615                 if( (gaPageDir[i] & 1) == 0 ) {
 616                         gaTmpDir[i] = 0;
 617                         continue;
 618                 }
 619
 620                 // We don't care about other kernel stacks, just the current one
 621                 if( i != kStackBase >> 22 ) {
 622                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 623                         gaTmpDir[i] = 0;
 624                         continue;
 625                 }
 626
 627                 // Create a copy
 628                 gaTmpDir[i] = MM_AllocPhys() | 3;
 629                 INVLPG( &gaTmpTable[i*1024] );
 630                 for( j = 0; j < 1024; j ++ )
 631                 {
 632                         // Is the page allocated? If not, skip
 633                         if( !(gaPageTable[i*1024+j] & 1) ) {
 634                                 gaTmpTable[i*1024+j] = 0;
 635                                 continue;
 636                         }
 637
 638                         // We don't care about other kernel stacks
 639                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 640                                 gaTmpTable[i*1024+j] = 0;
 641                                 continue;
 642                         }
 643
 644                         // Allocate page
 645                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 646
 647                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 648
 649                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 650                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 651                         MM_FreeTemp( (Uint)tmp );
 652                 }
 653         }
 654
 655         ret = *gpTmpCR3 & ~0xFFF;
 656         Mutex_Release( &glTempFractal );
 657
 658         //LEAVE('x', ret);
 659         return ret;
 660 }
 661
 662 /**
 663  * \fn tVAddr MM_NewKStack(void)
 664  * \brief Create a new kernel stack
 665  */
 666 tVAddr MM_NewKStack(void)
 667 {
 668         tVAddr  base;
 669         Uint    i;
 670         for(base = KERNEL_STACKS; base < KERNEL_STACKS_END; base += KERNEL_STACK_SIZE)
 671         {
 672                 // Check if space is free
 673                 if(MM_GetPhysAddr(base) != 0)   continue;
 674                 // Allocate
 675                 //for(i = KERNEL_STACK_SIZE; i -= 0x1000 ; )
 676                 for(i = 0; i < KERNEL_STACK_SIZE; i += 0x1000 )
 677                 {
 678                         if( MM_Allocate(base+i) == 0 )
 679                         {
 680                                 // On error, print a warning and return error
 681                                 Warning("MM_NewKStack - Out of memory");
 682                                 // - Clean up
 683                                 //for( i += 0x1000 ; i < KERNEL_STACK_SIZE; i += 0x1000 )
 684                                 //      MM_Deallocate(base+i);
 685                                 return 0;
 686                         }
 687                 }
 688                 // Success
 689                 Log("MM_NewKStack - Allocated %p", base + KERNEL_STACK_SIZE);
 690                 return base+KERNEL_STACK_SIZE;
 691         }
 692         // No stacks left
 693         Warning("MM_NewKStack - No address space left");
 694         return 0;
 695 }
 696
 697 /**
 698  * \fn tVAddr MM_NewWorkerStack()
 699  * \brief Creates a new worker stack
 700  */
 701 tVAddr MM_NewWorkerStack()
 702 {
 703         Uint    esp, ebp;
 704         Uint    oldstack;
 705         Uint    base, addr;
 706          int    i, j;
 707         Uint    *tmpPage;
 708         tPAddr  pages[WORKER_STACK_SIZE>>12];
 709
 710         // Get the old ESP and EBP
 711         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 712         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 713
 714         // TODO: Thread safety
 715         // Find a free worker stack address
 716         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 717         {
 718                 // Used block
 719                 if( gWorkerStacks[base/32] == -1 ) {
 720                         base += 31;     base &= ~31;
 721                         base --;        // Counteracted by the base++
 722                         continue;
 723                 }
 724                 // Used stack
 725                 if( gWorkerStacks[base/32] & (1 << base) ) {
 726                         continue;
 727                 }
 728                 break;
 729         }
 730         if(base >= NUM_WORKER_STACKS) {
 731                 Warning("Uh-oh! Out of worker stacks");
 732                 return 0;
 733         }
 734
 735         // It's ours now!
 736         gWorkerStacks[base/32] |= (1 << base);
 737         // Make life easier for later calls
 738         giLastUsedWorker = base;
 739         // We have one
 740         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 741         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 742
 743         // Acquire the lock for the temp fractal mappings
 744         Mutex_Acquire(&glTempFractal);
 745
 746         // Set the temp fractals to TID0's address space
 747         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 748         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 749         INVLPG( gaTmpDir );
 750
 751
 752         // Check if the directory is mapped (we are assuming that the stacks
 753         // will fit neatly in a directory)
 754         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 755         if(gaTmpDir[ base >> 22 ] == 0) {
 756                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 757                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 758         }
 759
 760         // Mapping Time!
 761         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 762         //for( addr = WORKER_STACK_SIZE; addr; addr -= 0x1000 )
 763         {
 764                 pages[ addr >> 12 ] = MM_AllocPhys();
 765                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 766         }
 767         *gpTmpCR3 = 0;
 768         // Release the temp mapping lock
 769         Mutex_Release(&glTempFractal);
 770
 771         // Copy the old stack
 772         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 773         esp = oldstack - esp;   // ESP as an offset in the stack
 774
 775         // Make `base` be the top of the stack
 776         base += WORKER_STACK_SIZE;
 777
 778         i = (WORKER_STACK_SIZE>>12) - 1;
 779         // Copy the contents of the old stack to the new one, altering the addresses
 780         // `addr` is refering to bytes from the stack base (mem downwards)
 781         for(addr = 0; addr < esp; addr += 0x1000)
 782         {
 783                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 784                 tmpPage = (void*)MM_MapTemp( pages[i] );
 785                 // Copy old stack
 786                 for(j = 0; j < 1024; j++)
 787                 {
 788                         // Possible Stack address?
 789                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 790                                 tmpPage[j] = base - (oldstack - stack[j]);
 791                         else    // Seems not, best leave it alone
 792                                 tmpPage[j] = stack[j];
 793                 }
 794                 MM_FreeTemp((tVAddr)tmpPage);
 795                 i --;
 796         }
 797
 798         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 799         return base;
 800 }
 801
 802 /**
 803  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 804  * \brief Sets the flags on a page
 805  */
 806 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 807 {
 808         tTabEnt *ent;
 809         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 810         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 811
 812         ent = &gaPageTable[VAddr >> 12];
 813
 814         // Read-Only
 815         if( Mask & MM_PFLAG_RO )
 816         {
 817                 if( Flags & MM_PFLAG_RO ) {
 818                         *ent &= ~PF_WRITE;
 819                 }
 820                 else {
 821                         gaPageDir[VAddr >> 22] |= PF_WRITE;
 822                         *ent |= PF_WRITE;
 823                 }
 824         }
 825
 826         // Kernel
 827         if( Mask & MM_PFLAG_KERNEL )
 828         {
 829                 if( Flags & MM_PFLAG_KERNEL ) {
 830                         *ent &= ~PF_USER;
 831                 }
 832                 else {
 833                         gaPageDir[VAddr >> 22] |= PF_USER;
 834                         *ent |= PF_USER;
 835                 }
 836         }
 837
 838         // Copy-On-Write
 839         if( Mask & MM_PFLAG_COW )
 840         {
 841                 if( Flags & MM_PFLAG_COW ) {
 842                         *ent &= ~PF_WRITE;
 843                         *ent |= PF_COW;
 844                 }
 845                 else {
 846                         *ent &= ~PF_COW;
 847                         *ent |= PF_WRITE;
 848                 }
 849         }
 850
 851         //Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
 852         //      *ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 853 }
 854
 855 /**
 856  * \brief Get the flags on a page
 857  */
 858 Uint MM_GetFlags(tVAddr VAddr)
 859 {
 860         tTabEnt *ent;
 861         Uint    ret = 0;
 862
 863         // Validity Check
 864         if( !(gaPageDir[VAddr >> 22] & 1) )     return 0;
 865         if( !(gaPageTable[VAddr >> 12] & 1) )   return 0;
 866
 867         ent = &gaPageTable[VAddr >> 12];
 868
 869         // Read-Only
 870         if( !(*ent & PF_WRITE) )        ret |= MM_PFLAG_RO;
 871         // Kernel
 872         if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
 873         // Copy-On-Write
 874         if( *ent & PF_COW )     ret |= MM_PFLAG_COW;
 875
 876         return ret;
 877 }
 878
 879 /**
 880  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 881  * \brief Duplicates a virtual page to a physical one
 882  */
 883 tPAddr MM_DuplicatePage(tVAddr VAddr)
 884 {
 885         tPAddr  ret;
 886         Uint    temp;
 887          int    wasRO = 0;
 888
 889         //ENTER("xVAddr", VAddr);
 890
 891         // Check if mapped
 892         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 893         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 894
 895         // Page Align
 896         VAddr &= ~0xFFF;
 897
 898         // Allocate new page
 899         ret = MM_AllocPhys();
 900
 901         // Write-lock the page (to keep data constistent), saving its R/W state
 902         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 903         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 904         INVLPG( VAddr );
 905
 906         // Copy Data
 907         temp = MM_MapTemp(ret);
 908         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 909         MM_FreeTemp(temp);
 910
 911         // Restore Writeable status
 912         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 913         INVLPG(VAddr);
 914
 915         //LEAVE('X', ret);
 916         return ret;
 917 }
 918
 919 /**
 920  * \fn Uint MM_MapTemp(tPAddr PAddr)
 921  * \brief Create a temporary memory mapping
 922  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 923  */
 924 tVAddr MM_MapTemp(tPAddr PAddr)
 925 {
 926          int    i;
 927
 928         //ENTER("XPAddr", PAddr);
 929
 930         PAddr &= ~0xFFF;
 931
 932         //LOG("glTempMappings = %i", glTempMappings);
 933
 934         for(;;)
 935         {
 936                 Mutex_Acquire( &glTempMappings );
 937
 938                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 939                 {
 940                         // Check if page used
 941                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 942                         // Mark as used
 943                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 944                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 945                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 946                         Mutex_Release( &glTempMappings );
 947                         return TEMP_MAP_ADDR + (i << 12);
 948                 }
 949                 Mutex_Release( &glTempMappings );
 950                 Threads_Yield();        // TODO: Use a sleep queue here instead
 951         }
 952 }
 953
 954 /**
 955  * \fn void MM_FreeTemp(tVAddr PAddr)
 956  * \brief Free's a temp mapping
 957  */
 958 void MM_FreeTemp(tVAddr VAddr)
 959 {
 960          int    i = VAddr >> 12;
 961         //ENTER("xVAddr", VAddr);
 962
 963         if(i >= (TEMP_MAP_ADDR >> 12))
 964                 gaPageTable[ i ] = 0;
 965
 966         //LEAVE('-');
 967 }
 968
 969 /**
 970  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 971  * \brief Allocates a contigous number of pages
 972  */
 973 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 974 {
 975          int    i, j;
 976
 977         PAddr &= ~0xFFF;
 978
 979         // Scan List
 980         for( i = 0; i < NUM_HW_PAGES; i ++ )
 981         {
 982                 // Check if addr used
 983                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 984                         continue;
 985
 986                 // Check possible region
 987                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 988                 {
 989                         // If there is an allocated page in the region we are testing, break
 990                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 991                 }
 992                 // Is it all free?
 993                 if( j == Number )
 994                 {
 995                         // Allocate
 996                         for( j = 0; j < Number; j++ ) {
 997                                 MM_RefPhys( PAddr + (j<<12) );
 998                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 999                         }
1000                         return HW_MAP_ADDR + (i<<12);
1001                 }
1002         }
1003         // If we don't find any, return NULL
1004         return 0;
1005 }
1006
1007 /**
1008  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
1009  * \brief Allocates DMA physical memory
1010  * \param Pages Number of pages required
1011  * \param MaxBits       Maximum number of bits the physical address can have
1012  * \param PhysAddr      Pointer to the location to place the physical address allocated
1013  * \return Virtual address allocate
1014  */
1015 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
1016 {
1017         tPAddr  maxCheck = (1 << MaxBits);
1018         tPAddr  phys;
1019         tVAddr  ret;
1020
1021         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
1022
1023         // Sanity Check
1024         if(MaxBits < 12 || !PhysAddr) {
1025                 LEAVE('i', 0);
1026                 return 0;
1027         }
1028
1029         // Bound
1030         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
1031
1032         // Fast Allocate
1033         if(Pages == 1 && MaxBits >= PHYS_BITS)
1034         {
1035                 phys = MM_AllocPhys();
1036                 *PhysAddr = phys;
1037                 ret = MM_MapHWPages(phys, 1);
1038                 if(ret == 0) {
1039                         MM_DerefPhys(phys);
1040                         LEAVE('i', 0);
1041                         return 0;
1042                 }
1043                 LEAVE('x', ret);
1044                 return ret;
1045         }
1046
1047         // Slow Allocate
1048         phys = MM_AllocPhysRange(Pages, MaxBits);
1049         // - Was it allocated?
1050         if(phys == 0) {
1051                 LEAVE('i', 0);
1052                 return 0;
1053         }
1054
1055         // Allocated successfully, now map
1056         ret = MM_MapHWPages(phys, Pages);
1057         if( ret == 0 ) {
1058                 // If it didn't map, free then return 0
1059                 for(;Pages--;phys+=0x1000)
1060                         MM_DerefPhys(phys);
1061                 LEAVE('i', 0);
1062                 return 0;
1063         }
1064
1065         *PhysAddr = phys;
1066         LEAVE('x', ret);
1067         return ret;
1068 }
1069
1070 /**
1071  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1072  * \brief Unmap a hardware page
1073  */
1074 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1075 {
1076          int    i, j;
1077
1078         //Log_Debug("VirtMem", "MM_UnmapHWPages: (VAddr=0x%08x, Number=%i)", VAddr, Number);
1079
1080         // Sanity Check
1081         if(VAddr < HW_MAP_ADDR || VAddr+Number*0x1000 > HW_MAP_MAX)     return;
1082
1083         i = VAddr >> 12;
1084
1085         Mutex_Acquire( &glTempMappings );       // Temp and HW share a directory, so they share a lock
1086
1087         for( j = 0; j < Number; j++ )
1088         {
1089                 MM_DerefPhys( gaPageTable[ i + j ] & ~0xFFF );
1090                 gaPageTable[ i + j ] = 0;
1091         }
1092
1093         Mutex_Release( &glTempMappings );
1094 }
1095