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_COW          0x200
  59 #define PF_PAGED        0x400
  60
  61 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  62
  63 #if USE_PAE
  64 typedef Uint64  tTabEnt;
  65 #else
  66 typedef Uint32  tTabEnt;
  67 #endif
  68
  69 // === IMPORTS ===
  70 extern void     _UsertextEnd, _UsertextBase;
  71 extern Uint32   gaInitPageDir[1024];
  72 extern Uint32   gaInitPageTable[1024];
  73 extern void     Threads_SegFault(tVAddr Addr);
  74 extern void     Error_Backtrace(Uint eip, Uint ebp);
  75
  76 // === PROTOTYPES ===
  77 void    MM_PreinitVirtual(void);
  78 void    MM_InstallVirtual(void);
  79 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  80 void    MM_DumpTables(tVAddr Start, tVAddr End);
  81 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  82
  83 // === GLOBALS ===
  84 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  85 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  86 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  87 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  88 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  89 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  90
  91 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  92 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  93 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  94 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  95 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  96 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  97  int    gbUsePAE = 0;
  98  int    gilTempMappings = 0;
  99  int    gilTempFractal = 0;
 100 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
 101  int    giLastUsedWorker = 0;
 102
 103 // === CODE ===
 104 /**
 105  * \fn void MM_PreinitVirtual(void)
 106  * \brief Maps the fractal mappings
 107  */
 108 void MM_PreinitVirtual(void)
 109 {
 110         #if USE_PAE
 111         gaInitPageDir[ ((PAGE_TABLE_ADDR >> TAB)-3*512+3)*2 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 112         #else
 113         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 114         #endif
 115         INVLPG( PAGE_TABLE_ADDR );
 116 }
 117
 118 /**
 119  * \fn void MM_InstallVirtual(void)
 120  * \brief Sets up the constant page mappings
 121  */
 122 void MM_InstallVirtual(void)
 123 {
 124          int    i;
 125
 126         #if USE_PAE
 127         // --- Pre-Allocate kernel tables
 128         for( i = KERNEL_BASE >> TAB; i < 1024*4; i ++ )
 129         {
 130                 if( gaPAE_PageDir[ i ] )        continue;
 131
 132                 // Skip stack tables, they are process unique
 133                 if( i > KERNEL_STACKS >> TAB && i < KERNEL_STACKS_END >> TAB) {
 134                         gaPAE_PageDir[ i ] = 0;
 135                         continue;
 136                 }
 137                 // Preallocate table
 138                 gaPAE_PageDir[ i ] = MM_AllocPhys() | 3;
 139                 INVLPG( &gaPAE_PageTable[i*512] );
 140                 memset( &gaPAE_PageTable[i*512], 0, 0x1000 );
 141         }
 142         #else
 143         // --- Pre-Allocate kernel tables
 144         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 145         {
 146                 if( gaPageDir[ i ] )    continue;
 147                 // Skip stack tables, they are process unique
 148                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 149                         gaPageDir[ i ] = 0;
 150                         continue;
 151                 }
 152                 // Preallocate table
 153                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 154                 INVLPG( &gaPageTable[i*1024] );
 155                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 156         }
 157         #endif
 158
 159         // Unset kernel on the User Text pages
 160         for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
 161                 Log("MM_SetFlags( 0x%08x, 0, MM_PFLAG_KERNEL)", (tVAddr)&_UsertextBase + i*4096);
 162                 MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
 163         }
 164 }
 165
 166 /**
 167  * \brief Cleans up the SMP required mappings
 168  */
 169 void MM_FinishVirtualInit(void)
 170 {
 171         #if USE_PAE
 172         gaInitPDPT[ 0 ] = 0;
 173         #else
 174         gaInitPageDir[ 0 ] = 0;
 175         #endif
 176 }
 177
 178 /**
 179  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 180  * \brief Called on a page fault
 181  */
 182 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 183 {
 184         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 185
 186         // -- Check for COW --
 187         if( gaPageDir  [Addr>>22] & PF_PRESENT
 188          && gaPageTable[Addr>>12] & PF_PRESENT
 189          && gaPageTable[Addr>>12] & PF_COW )
 190         {
 191                 tPAddr  paddr;
 192                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 193                 {
 194                         gaPageTable[Addr>>12] &= ~PF_COW;
 195                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 196                 }
 197                 else
 198                 {
 199                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 200                         paddr = MM_DuplicatePage( Addr );
 201                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 202                         gaPageTable[Addr>>12] &= PF_USER;
 203                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 204                 }
 205
 206                 INVLPG( Addr & ~0xFFF );
 207                 //LEAVE('-')
 208                 return;
 209         }
 210
 211         // If it was a user, tell the thread handler
 212         if(ErrorCode & 4) {
 213                 Warning("%s %s %s memory%s",
 214                         (ErrorCode&4?"User":"Kernel"),
 215                         (ErrorCode&2?"write to":"read from"),
 216                         (ErrorCode&1?"bad/locked":"non-present"),
 217                         (ErrorCode&16?" (Instruction Fetch)":"")
 218                         );
 219                 Warning("User Pagefault: Instruction at %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 220                 __asm__ __volatile__ ("sti");   // Restart IRQs
 221                 Threads_SegFault(Addr);
 222                 return ;
 223         }
 224
 225         Debug_KernelPanic();
 226
 227         // -- Check Error Code --
 228         if(ErrorCode & 8)
 229                 Warning("Reserved Bits Trashed!");
 230         else
 231         {
 232                 Warning("%s %s %s memory%s",
 233                         (ErrorCode&4?"User":"Kernel"),
 234                         (ErrorCode&2?"write to":"read from"),
 235                         (ErrorCode&1?"bad/locked":"non-present"),
 236                         (ErrorCode&16?" (Instruction Fetch)":"")
 237                         );
 238         }
 239
 240         Log("Code at %p accessed %p", Regs->eip, Addr);
 241         // Print Stack Backtrace
 242         Error_Backtrace(Regs->eip, Regs->ebp);
 243
 244         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 245         if( gaPageDir[Addr>>22] & PF_PRESENT )
 246                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 247
 248         //MM_DumpTables(0, -1);
 249
 250         // Register Dump
 251         Log("EAX %08x ECX %08x EDX %08x EBX %08x", Regs->eax, Regs->ecx, Regs->edx, Regs->ebx);
 252         Log("ESP %08x EBP %08x ESI %08x EDI %08x", Regs->esp, Regs->ebp, Regs->esi, Regs->edi);
 253         //Log("SS:ESP %04x:%08x", Regs->ss, Regs->esp);
 254         Log("CS:EIP %04x:%08x", Regs->cs, Regs->eip);
 255         Log("DS %04x ES %04x FS %04x GS %04x", Regs->ds, Regs->es, Regs->fs, Regs->gs);
 256
 257         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 258 }
 259
 260 /**
 261  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 262  * \brief Dumps the layout of the page tables
 263  */
 264 void MM_DumpTables(tVAddr Start, tVAddr End)
 265 {
 266         tVAddr  rangeStart = 0;
 267         tPAddr  expected = 0;
 268         tVAddr  curPos;
 269         Uint    page;
 270         const tPAddr    MASK = ~0xF98;
 271
 272         Start >>= 12;   End >>= 12;
 273
 274         #if 0
 275         Log("Directory Entries:");
 276         for(page = Start >> 10;
 277                 page < (End >> 10)+1;
 278                 page ++)
 279         {
 280                 if(gaPageDir[page])
 281                 {
 282                         Log(" 0x%08x-0x%08x :: 0x%08x",
 283                                 page<<22, ((page+1)<<22)-1,
 284                                 gaPageDir[page]&~0xFFF
 285                                 );
 286                 }
 287         }
 288         #endif
 289
 290         Log("Table Entries:");
 291         for(page = Start, curPos = Start<<12;
 292                 page < End;
 293                 curPos += 0x1000, page++)
 294         {
 295                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 296                 ||  !(gaPageTable[page] & PF_PRESENT)
 297                 ||  (gaPageTable[page] & MASK) != expected)
 298                 {
 299                         if(expected) {
 300                                 Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 301                                         rangeStart, curPos - 1,
 302                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 303                                         (expected & ~0xFFF) - 1,
 304                                         (expected & PF_PAGED ? "p" : "-"),
 305                                         (expected & PF_COW ? "C" : "-"),
 306                                         (expected & PF_USER ? "U" : "-"),
 307                                         (expected & PF_WRITE ? "W" : "-")
 308                                         );
 309                                 expected = 0;
 310                         }
 311                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 312                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 313
 314                         expected = (gaPageTable[page] & MASK);
 315                         rangeStart = curPos;
 316                 }
 317                 if(expected)    expected += 0x1000;
 318         }
 319
 320         if(expected) {
 321                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 322                         rangeStart, curPos - 1,
 323                         gaPageTable[rangeStart>>12] & ~0xFFF,
 324                         (expected & ~0xFFF) - 1,
 325                         (expected & PF_PAGED ? "p" : "-"),
 326                         (expected & PF_COW ? "C" : "-"),
 327                         (expected & PF_USER ? "U" : "-"),
 328                         (expected & PF_WRITE ? "W" : "-")
 329                         );
 330                 expected = 0;
 331         }
 332 }
 333
 334 /**
 335  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 336  */
 337 tPAddr MM_Allocate(tVAddr VAddr)
 338 {
 339         tPAddr  paddr;
 340         //ENTER("xVAddr", VAddr);
 341         //__asm__ __volatile__ ("xchg %bx,%bx");
 342         // Check if the directory is mapped
 343         if( gaPageDir[ VAddr >> 22 ] == 0 )
 344         {
 345                 // Allocate directory
 346                 paddr = MM_AllocPhys();
 347                 //LOG("paddr = 0x%llx (new table)", paddr);
 348                 if( paddr == 0 ) {
 349                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 350                         //LEAVE('i',0);
 351                         return 0;
 352                 }
 353                 // Map
 354                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 355                 // Mark as user
 356                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 357
 358                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 359                 //LOG("Clearing new table");
 360                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 361         }
 362         // Check if the page is already allocated
 363         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 364                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 365                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 366                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 367         }
 368
 369         // Allocate
 370         paddr = MM_AllocPhys();
 371         //LOG("paddr = 0x%llx", paddr);
 372         if( paddr == 0 ) {
 373                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 374                         VAddr, __builtin_return_address(0));
 375                 //LEAVE('i',0);
 376                 return 0;
 377         }
 378         // Map
 379         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 380         // Mark as user
 381         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 382         // Invalidate Cache for address
 383         INVLPG( VAddr & ~0xFFF );
 384
 385         //LEAVE('X', paddr);
 386         return paddr;
 387 }
 388
 389 /**
 390  * \fn void MM_Deallocate(tVAddr VAddr)
 391  */
 392 void MM_Deallocate(tVAddr VAddr)
 393 {
 394         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 395                 Warning("MM_Deallocate - Directory not mapped");
 396                 return;
 397         }
 398
 399         if(gaPageTable[ VAddr >> 12 ] == 0) {
 400                 Warning("MM_Deallocate - Page is not allocated");
 401                 return;
 402         }
 403
 404         // Dereference page
 405         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 406         // Clear page
 407         gaPageTable[ VAddr >> 12 ] = 0;
 408 }
 409
 410 /**
 411  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 412  * \brief Checks if the passed address is accesable
 413  */
 414 tPAddr MM_GetPhysAddr(tVAddr Addr)
 415 {
 416         if( !(gaPageDir[Addr >> 22] & 1) )
 417                 return 0;
 418         if( !(gaPageTable[Addr >> 12] & 1) )
 419                 return 0;
 420         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 421 }
 422
 423 /**
 424  * \fn void MM_SetCR3(Uint CR3)
 425  * \brief Sets the current process space
 426  */
 427 void MM_SetCR3(Uint CR3)
 428 {
 429         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 430 }
 431
 432 /**
 433  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 434  * \brief Map a physical page to a virtual one
 435  */
 436 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 437 {
 438         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 439         // Sanity check
 440         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 441                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 442                 //LEAVE('i', 0);
 443                 return 0;
 444         }
 445
 446         // Align addresses
 447         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 448
 449         // Check if the directory is mapped
 450         if( gaPageDir[ VAddr >> 22 ] == 0 )
 451         {
 452                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 453
 454                 // Mark as user
 455                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 456
 457                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 458                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 459         }
 460         // Check if the page is already allocated
 461         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 462                 Warning("MM_Map - Allocating to used address");
 463                 //LEAVE('i', 0);
 464                 return 0;
 465         }
 466
 467         // Map
 468         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 469         // Mark as user
 470         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 471
 472         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 473         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 474
 475         // Reference
 476         MM_RefPhys( PAddr );
 477
 478         //LOG("INVLPG( 0x%x )", VAddr);
 479         INVLPG( VAddr );
 480
 481         //LEAVE('i', 1);
 482         return 1;
 483 }
 484
 485 /**
 486  * \fn tVAddr MM_ClearUser()
 487  * \brief Clear user's address space
 488  */
 489 tVAddr MM_ClearUser(void)
 490 {
 491         Uint    i, j;
 492
 493         // Copy Directories
 494         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 495         {
 496                 // Check if directory is not allocated
 497                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 498                         gaPageDir[i] = 0;
 499                         continue;
 500                 }
 501
 502
 503                 for( j = 0; j < 1024; j ++ )
 504                 {
 505                         if( gaPageTable[i*1024+j] & 1 )
 506                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 507                         gaPageTable[i*1024+j] = 0;
 508                 }
 509
 510                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 511                 gaPageDir[i] = 0;
 512                 INVLPG( &gaPageTable[i*1024] );
 513         }
 514         INVLPG( gaPageDir );
 515
 516         return *gpPageCR3;
 517 }
 518
 519 /**
 520  * \fn tPAddr MM_Clone(void)
 521  * \brief Clone the current address space
 522  */
 523 tPAddr MM_Clone(void)
 524 {
 525         Uint    i, j;
 526         tVAddr  ret;
 527         Uint    page = 0;
 528         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 529         void    *tmp;
 530
 531         LOCK( &gilTempFractal );
 532
 533         // Create Directory Table
 534         *gpTmpCR3 = MM_AllocPhys() | 3;
 535         INVLPG( gaTmpDir );
 536         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 537         memsetd( gaTmpDir, 0, 1024 );
 538
 539         // Copy Tables
 540         for( i = 0; i < 768; i ++)
 541         {
 542                 // Check if table is allocated
 543                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 544                         gaTmpDir[i] = 0;
 545                         page += 1024;
 546                         continue;
 547                 }
 548
 549                 // Allocate new table
 550                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 551                 INVLPG( &gaTmpTable[page] );
 552                 // Fill
 553                 for( j = 0; j < 1024; j ++, page++ )
 554                 {
 555                         if( !(gaPageTable[page] & PF_PRESENT) ) {
 556                                 gaTmpTable[page] = 0;
 557                                 continue;
 558                         }
 559
 560                         // Refrence old page
 561                         MM_RefPhys( gaPageTable[page] & ~0xFFF );
 562                         // Add to new table
 563                         if(gaPageTable[page] & PF_WRITE) {
 564                                 gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 565                                 gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 566                                 INVLPG( page << 12 );
 567                         }
 568                         else
 569                                 gaTmpTable[page] = gaPageTable[page];
 570                 }
 571         }
 572
 573         // Map in kernel tables (and make fractal mapping)
 574         for( i = 768; i < 1024; i ++ )
 575         {
 576                 // Fractal
 577                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 578                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 579                         continue;
 580                 }
 581
 582                 if( gaPageDir[i] == 0 ) {
 583                         gaTmpDir[i] = 0;
 584                         continue;
 585                 }
 586
 587                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 588                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 589                 gaTmpDir[i] = gaPageDir[i];
 590         }
 591
 592         // Allocate kernel stack
 593         for(i = KERNEL_STACKS >> 22;
 594                 i < KERNEL_STACKS_END >> 22;
 595                 i ++ )
 596         {
 597                 // Check if directory is allocated
 598                 if( (gaPageDir[i] & 1) == 0 ) {
 599                         gaTmpDir[i] = 0;
 600                         continue;
 601                 }
 602
 603                 // We don't care about other kernel stacks, just the current one
 604                 if( i != kStackBase >> 22 ) {
 605                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 606                         gaTmpDir[i] = 0;
 607                         continue;
 608                 }
 609
 610                 // Create a copy
 611                 gaTmpDir[i] = MM_AllocPhys() | 3;
 612                 INVLPG( &gaTmpTable[i*1024] );
 613                 for( j = 0; j < 1024; j ++ )
 614                 {
 615                         // Is the page allocated? If not, skip
 616                         if( !(gaPageTable[i*1024+j] & 1) ) {
 617                                 gaTmpTable[i*1024+j] = 0;
 618                                 continue;
 619                         }
 620
 621                         // We don't care about other kernel stacks
 622                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 623                                 gaTmpTable[i*1024+j] = 0;
 624                                 continue;
 625                         }
 626
 627                         // Allocate page
 628                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 629
 630                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 631
 632                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 633                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 634                         MM_FreeTemp( (Uint)tmp );
 635                 }
 636         }
 637
 638         ret = *gpTmpCR3 & ~0xFFF;
 639         RELEASE( &gilTempFractal );
 640
 641         //LEAVE('x', ret);
 642         return ret;
 643 }
 644
 645 /**
 646  * \fn tVAddr MM_NewKStack(void)
 647  * \brief Create a new kernel stack
 648  */
 649 tVAddr MM_NewKStack(void)
 650 {
 651         tVAddr  base = KERNEL_STACKS;
 652         Uint    i;
 653         for(;base<KERNEL_STACKS_END;base+=KERNEL_STACK_SIZE)
 654         {
 655                 if(MM_GetPhysAddr(base) != 0)   continue;
 656                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 657                         MM_Allocate(base+i);
 658                 }
 659                 return base+KERNEL_STACK_SIZE;
 660         }
 661         Warning("MM_NewKStack - No address space left\n");
 662         return 0;
 663 }
 664
 665 /**
 666  * \fn tVAddr MM_NewWorkerStack()
 667  * \brief Creates a new worker stack
 668  */
 669 tVAddr MM_NewWorkerStack()
 670 {
 671         Uint    esp, ebp;
 672         Uint    oldstack;
 673         Uint    base, addr;
 674          int    i, j;
 675         Uint    *tmpPage;
 676         tPAddr  pages[WORKER_STACK_SIZE>>12];
 677
 678         // Get the old ESP and EBP
 679         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 680         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 681
 682         // Find a free worker stack address
 683         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 684         {
 685                 // Used block
 686                 if( gWorkerStacks[base/32] == -1 ) {
 687                         base += 31;     base &= ~31;
 688                         base --;        // Counteracted by the base++
 689                         continue;
 690                 }
 691                 // Used stack
 692                 if( gWorkerStacks[base/32] & (1 << base) ) {
 693                         continue;
 694                 }
 695                 break;
 696         }
 697         if(base >= NUM_WORKER_STACKS) {
 698                 Warning("Uh-oh! Out of worker stacks");
 699                 return 0;
 700         }
 701
 702         // It's ours now!
 703         gWorkerStacks[base/32] |= (1 << base);
 704         // Make life easier for later calls
 705         giLastUsedWorker = base;
 706         // We have one
 707         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 708         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 709
 710         // Acquire the lock for the temp fractal mappings
 711         LOCK(&gilTempFractal);
 712
 713         // Set the temp fractals to TID0's address space
 714         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 715         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 716         INVLPG( gaTmpDir );
 717
 718
 719         // Check if the directory is mapped (we are assuming that the stacks
 720         // will fit neatly in a directory)
 721         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 722         if(gaTmpDir[ base >> 22 ] == 0) {
 723                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 724                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 725         }
 726
 727         // Mapping Time!
 728         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 729         {
 730                 pages[ addr >> 12 ] = MM_AllocPhys();
 731                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 732         }
 733         *gpTmpCR3 = 0;
 734         // Release the temp mapping lock
 735         RELEASE(&gilTempFractal);
 736
 737         // Copy the old stack
 738         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 739         esp = oldstack - esp;   // ESP as an offset in the stack
 740
 741         // Make `base` be the top of the stack
 742         base += WORKER_STACK_SIZE;
 743
 744         i = (WORKER_STACK_SIZE>>12) - 1;
 745         // Copy the contents of the old stack to the new one, altering the addresses
 746         // `addr` is refering to bytes from the stack base (mem downwards)
 747         for(addr = 0; addr < esp; addr += 0x1000)
 748         {
 749                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 750                 tmpPage = (void*)MM_MapTemp( pages[i] );
 751                 // Copy old stack
 752                 for(j = 0; j < 1024; j++)
 753                 {
 754                         // Possible Stack address?
 755                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 756                                 tmpPage[j] = base - (oldstack - stack[j]);
 757                         else    // Seems not, best leave it alone
 758                                 tmpPage[j] = stack[j];
 759                 }
 760                 MM_FreeTemp((tVAddr)tmpPage);
 761                 i --;
 762         }
 763
 764         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 765         return base;
 766 }
 767
 768 /**
 769  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 770  * \brief Sets the flags on a page
 771  */
 772 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 773 {
 774         tTabEnt *ent;
 775         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 776         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 777
 778         ent = &gaPageTable[VAddr >> 12];
 779
 780         // Read-Only
 781         if( Mask & MM_PFLAG_RO )
 782         {
 783                 if( Flags & MM_PFLAG_RO ) {
 784                         *ent &= ~PF_WRITE;
 785                 }
 786                 else {
 787                         gaPageDir[VAddr >> 22] |= PF_WRITE;
 788                         *ent |= PF_WRITE;
 789                 }
 790         }
 791
 792         // Kernel
 793         if( Mask & MM_PFLAG_KERNEL )
 794         {
 795                 if( Flags & MM_PFLAG_KERNEL ) {
 796                         *ent &= ~PF_USER;
 797                 }
 798                 else {
 799                         gaPageDir[VAddr >> 22] |= PF_USER;
 800                         *ent |= PF_USER;
 801                 }
 802         }
 803
 804         // Copy-On-Write
 805         if( Mask & MM_PFLAG_COW )
 806         {
 807                 if( Flags & MM_PFLAG_COW ) {
 808                         *ent &= ~PF_WRITE;
 809                         *ent |= PF_COW;
 810                 }
 811                 else {
 812                         *ent &= ~PF_COW;
 813                         *ent |= PF_WRITE;
 814                 }
 815         }
 816
 817         //Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
 818         //      *ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 819 }
 820
 821 /**
 822  * \brief Get the flags on a page
 823  */
 824 Uint MM_GetFlags(tVAddr VAddr)
 825 {
 826         tTabEnt *ent;
 827         Uint    ret = 0;
 828
 829         // Validity Check
 830         if( !(gaPageDir[VAddr >> 22] & 1) )     return 0;
 831         if( !(gaPageTable[VAddr >> 12] & 1) )   return 0;
 832
 833         ent = &gaPageTable[VAddr >> 12];
 834
 835         // Read-Only
 836         if( !(*ent & PF_WRITE) )        ret |= MM_PFLAG_RO;
 837         // Kernel
 838         if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
 839         // Copy-On-Write
 840         if( *ent & PF_COW )     ret |= MM_PFLAG_COW;
 841
 842         return ret;
 843 }
 844
 845 /**
 846  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 847  * \brief Duplicates a virtual page to a physical one
 848  */
 849 tPAddr MM_DuplicatePage(tVAddr VAddr)
 850 {
 851         tPAddr  ret;
 852         Uint    temp;
 853          int    wasRO = 0;
 854
 855         //ENTER("xVAddr", VAddr);
 856
 857         // Check if mapped
 858         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 859         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 860
 861         // Page Align
 862         VAddr &= ~0xFFF;
 863
 864         // Allocate new page
 865         ret = MM_AllocPhys();
 866
 867         // Write-lock the page (to keep data constistent), saving its R/W state
 868         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 869         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 870         INVLPG( VAddr );
 871
 872         // Copy Data
 873         temp = MM_MapTemp(ret);
 874         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 875         MM_FreeTemp(temp);
 876
 877         // Restore Writeable status
 878         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 879         INVLPG(VAddr);
 880
 881         //LEAVE('X', ret);
 882         return ret;
 883 }
 884
 885 /**
 886  * \fn Uint MM_MapTemp(tPAddr PAddr)
 887  * \brief Create a temporary memory mapping
 888  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 889  */
 890 tVAddr MM_MapTemp(tPAddr PAddr)
 891 {
 892          int    i;
 893
 894         //ENTER("XPAddr", PAddr);
 895
 896         PAddr &= ~0xFFF;
 897
 898         //LOG("gilTempMappings = %i", gilTempMappings);
 899
 900         for(;;)
 901         {
 902                 LOCK( &gilTempMappings );
 903
 904                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 905                 {
 906                         // Check if page used
 907                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 908                         // Mark as used
 909                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 910                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 911                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 912                         RELEASE( &gilTempMappings );
 913                         return TEMP_MAP_ADDR + (i << 12);
 914                 }
 915                 RELEASE( &gilTempMappings );
 916                 Threads_Yield();
 917         }
 918 }
 919
 920 /**
 921  * \fn void MM_FreeTemp(tVAddr PAddr)
 922  * \brief Free's a temp mapping
 923  */
 924 void MM_FreeTemp(tVAddr VAddr)
 925 {
 926          int    i = VAddr >> 12;
 927         //ENTER("xVAddr", VAddr);
 928
 929         if(i >= (TEMP_MAP_ADDR >> 12))
 930                 gaPageTable[ i ] = 0;
 931
 932         //LEAVE('-');
 933 }
 934
 935 /**
 936  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 937  * \brief Allocates a contigous number of pages
 938  */
 939 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 940 {
 941          int    i, j;
 942
 943         PAddr &= ~0xFFF;
 944
 945         // Scan List
 946         for( i = 0; i < NUM_HW_PAGES; i ++ )
 947         {
 948                 // Check if addr used
 949                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 950                         continue;
 951
 952                 // Check possible region
 953                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 954                 {
 955                         // If there is an allocated page in the region we are testing, break
 956                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 957                 }
 958                 // Is it all free?
 959                 if( j == Number )
 960                 {
 961                         // Allocate
 962                         for( j = 0; j < Number; j++ ) {
 963                                 MM_RefPhys( PAddr + (j<<12) );
 964                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 965                         }
 966                         return HW_MAP_ADDR + (i<<12);
 967                 }
 968         }
 969         // If we don't find any, return NULL
 970         return 0;
 971 }
 972
 973 /**
 974  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 975  * \brief Allocates DMA physical memory
 976  * \param Pages Number of pages required
 977  * \param MaxBits       Maximum number of bits the physical address can have
 978  * \param PhysAddr      Pointer to the location to place the physical address allocated
 979  * \return Virtual address allocate
 980  */
 981 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 982 {
 983         tPAddr  maxCheck = (1 << MaxBits);
 984         tPAddr  phys;
 985         tVAddr  ret;
 986
 987         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
 988
 989         // Sanity Check
 990         if(MaxBits < 12 || !PhysAddr) {
 991                 LEAVE('i', 0);
 992                 return 0;
 993         }
 994
 995         // Bound
 996         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
 997
 998         // Fast Allocate
 999         if(Pages == 1 && MaxBits >= PHYS_BITS)
1000         {
1001                 phys = MM_AllocPhys();
1002                 *PhysAddr = phys;
1003                 ret = MM_MapHWPages(phys, 1);
1004                 if(ret == 0) {
1005                         MM_DerefPhys(phys);
1006                         LEAVE('i', 0);
1007                         return 0;
1008                 }
1009                 LEAVE('x', ret);
1010                 return ret;
1011         }
1012
1013         // Slow Allocate
1014         phys = MM_AllocPhysRange(Pages, MaxBits);
1015         // - Was it allocated?
1016         if(phys == 0) {
1017                 LEAVE('i', 0);
1018                 return 0;
1019         }
1020
1021         // Allocated successfully, now map
1022         ret = MM_MapHWPages(phys, Pages);
1023         if( ret == 0 ) {
1024                 // If it didn't map, free then return 0
1025                 for(;Pages--;phys+=0x1000)
1026                         MM_DerefPhys(phys);
1027                 LEAVE('i', 0);
1028                 return 0;
1029         }
1030
1031         *PhysAddr = phys;
1032         LEAVE('x', ret);
1033         return ret;
1034 }
1035
1036 /**
1037  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1038  * \brief Unmap a hardware page
1039  */
1040 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1041 {
1042          int    i, j;
1043
1044         //Log_Debug("VirtMem", "MM_UnmapHWPages: (VAddr=0x%08x, Number=%i)", VAddr, Number);
1045
1046         // Sanity Check
1047         if(VAddr < HW_MAP_ADDR || VAddr+Number*0x1000 > HW_MAP_MAX)     return;
1048
1049         i = VAddr >> 12;
1050
1051         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
1052
1053
1054         for( j = 0; j < Number; j++ )
1055         {
1056                 MM_DerefPhys( gaPageTable[ i + j ] & ~0xFFF );
1057                 gaPageTable[ i + j ] = 0;
1058         }
1059
1060         RELEASE( &gilTempMappings );
1061 }
1062
1063 // --- EXPORTS ---
1064 EXPORT(MM_GetPhysAddr);
1065 EXPORT(MM_Map);
1066 //EXPORT(MM_Unmap);
1067 EXPORT(MM_MapHWPages);
1068 EXPORT(MM_AllocDMA);
1069 EXPORT(MM_UnmapHWPages);