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