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