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