Kernel/arch/x86/mm_virt.c

   1 /*
   2  * AcessOS Microkernel Version
   3  * mm_virt.c
   4  *
   5  * Memory Map
   6  * 0xE0 - Kernel Base
   7  * 0xF0 - Kernel Stacks
   8  * 0xFD - Fractals
   9  * 0xFE - Unused
  10  * 0xFF - System Calls / Kernel's User Code
  11  */
  12 #define DEBUG   0
  13 #define SANITY  1
  14 #include <acess.h>
  15 #include <mm_virt.h>
  16 #include <mm_phys.h>
  17 #include <proc.h>
  18
  19 #if USE_PAE
  20 # define TAB    21
  21 # define DIR    30
  22 #else
  23 # define TAB    22
  24 #endif
  25
  26 #define KERNEL_STACKS           0xF0000000
  27 #define KERNEL_STACK_SIZE       0x00008000
  28 #define KERNEL_STACKS_END       0xFC000000
  29 #define WORKER_STACKS           0x00100000      // Thread0 Only!
  30 #define WORKER_STACK_SIZE       KERNEL_STACK_SIZE
  31 #define WORKER_STACKS_END       0xB0000000
  32 #define NUM_WORKER_STACKS       ((WORKER_STACKS_END-WORKER_STACKS)/WORKER_STACK_SIZE)
  33
  34 #define PAE_PAGE_TABLE_ADDR     0xFC000000      // 16 MiB
  35 #define PAE_PAGE_DIR_ADDR       0xFCFC0000      // 16 KiB
  36 #define PAE_PAGE_PDPT_ADDR      0xFCFC3F00      // 32 bytes
  37 #define PAE_TMP_PDPT_ADDR       0xFCFC3F20      // 32 bytes
  38 #define PAE_TMP_DIR_ADDR        0xFCFE0000      // 16 KiB
  39 #define PAE_TMP_TABLE_ADDR      0xFD000000      // 16 MiB
  40
  41 #define PAGE_TABLE_ADDR 0xFC000000
  42 #define PAGE_DIR_ADDR   0xFC3F0000
  43 #define PAGE_CR3_ADDR   0xFC3F0FC0
  44 #define TMP_CR3_ADDR    0xFC3F0FC4      // Part of core instead of temp
  45 #define TMP_DIR_ADDR    0xFC3F1000      // Same
  46 #define TMP_TABLE_ADDR  0xFC400000
  47
  48 #define HW_MAP_ADDR             0xFE000000
  49 #define HW_MAP_MAX              0xFFEF0000
  50 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  51 #define TEMP_MAP_ADDR   0xFFEF0000      // Allows 16 "temp" pages
  52 #define NUM_TEMP_PAGES  16
  53 #define LAST_BLOCK_ADDR 0xFFFF0000      // Free space for kernel provided user code/ *(-1) protection
  54
  55 #define PF_PRESENT      0x1
  56 #define PF_WRITE        0x2
  57 #define PF_USER         0x4
  58 #define PF_GLOBAL       0x80
  59 #define PF_COW          0x200
  60 #define PF_NOPAGE       0x400
  61
  62 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  63
  64 #if USE_PAE
  65 typedef Uint64  tTabEnt;
  66 #else
  67 typedef Uint32  tTabEnt;
  68 #endif
  69
  70 // === IMPORTS ===
  71 extern void     _UsertextEnd, _UsertextBase;
  72 extern Uint32   gaInitPageDir[1024];
  73 extern Uint32   gaInitPageTable[1024];
  74 extern void     Threads_SegFault(tVAddr Addr);
  75 extern void     Error_Backtrace(Uint eip, Uint ebp);
  76
  77 // === PROTOTYPES ===
  78 void    MM_PreinitVirtual(void);
  79 void    MM_InstallVirtual(void);
  80 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  81 void    MM_DumpTables(tVAddr Start, tVAddr End);
  82 tVAddr  MM_ClearUser(void);
  83 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  84
  85 // === GLOBALS ===
  86 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  87 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  88 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  89 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  90 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  91 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  92
  93 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  94 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  95 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  96 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  97 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  98 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  99  int    gbUsePAE = 0;
 100 tMutex  glTempMappings;
 101 tMutex  glTempFractal;
 102 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
 103  int    giLastUsedWorker = 0;
 104
 105 // === CODE ===
 106 /**
 107  * \fn void MM_PreinitVirtual(void)
 108  * \brief Maps the fractal mappings
 109  */
 110 void MM_PreinitVirtual(void)
 111 {
 112         #if USE_PAE
 113         gaInitPageDir[ ((PAGE_TABLE_ADDR >> TAB)-3*512+3)*2 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 114         #else
 115         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 116         #endif
 117         INVLPG( PAGE_TABLE_ADDR );
 118 }
 119
 120 /**
 121  * \fn void MM_InstallVirtual(void)
 122  * \brief Sets up the constant page mappings
 123  */
 124 void MM_InstallVirtual(void)
 125 {
 126          int    i;
 127
 128         #if USE_PAE
 129         // --- Pre-Allocate kernel tables
 130         for( i = KERNEL_BASE >> TAB; i < 1024*4; i ++ )
 131         {
 132                 if( gaPAE_PageDir[ i ] )        continue;
 133
 134                 // Skip stack tables, they are process unique
 135                 if( i > KERNEL_STACKS >> TAB && i < KERNEL_STACKS_END >> TAB) {
 136                         gaPAE_PageDir[ i ] = 0;
 137                         continue;
 138                 }
 139                 // Preallocate table
 140                 gaPAE_PageDir[ i ] = MM_AllocPhys() | 3;
 141                 INVLPG( &gaPAE_PageTable[i*512] );
 142                 memset( &gaPAE_PageTable[i*512], 0, 0x1000 );
 143         }
 144         #else
 145         // --- Pre-Allocate kernel tables
 146         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 147         {
 148                 if( gaPageDir[ i ] )    continue;
 149                 // Skip stack tables, they are process unique
 150                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 151                         gaPageDir[ i ] = 0;
 152                         continue;
 153                 }
 154                 // Preallocate table
 155                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 156                 INVLPG( &gaPageTable[i*1024] );
 157                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 158         }
 159         #endif
 160
 161         // Unset kernel on the User Text pages
 162         for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
 163                 MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
 164         }
 165 }
 166
 167 /**
 168  * \brief Cleans up the SMP required mappings
 169  */
 170 void MM_FinishVirtualInit(void)
 171 {
 172         #if USE_PAE
 173         gaInitPDPT[ 0 ] = 0;
 174         #else
 175         gaInitPageDir[ 0 ] = 0;
 176         #endif
 177 }
 178
 179 /**
 180  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 181  * \brief Called on a page fault
 182  */
 183 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 184 {
 185         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 186
 187         // -- Check for COW --
 188         if( gaPageDir  [Addr>>22] & PF_PRESENT
 189          && gaPageTable[Addr>>12] & PF_PRESENT
 190          && gaPageTable[Addr>>12] & PF_COW )
 191         {
 192                 tPAddr  paddr;
 193                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 194                 {
 195                         gaPageTable[Addr>>12] &= ~PF_COW;
 196                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 197                 }
 198                 else
 199                 {
 200                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 201                         paddr = MM_DuplicatePage( Addr );
 202                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 203                         gaPageTable[Addr>>12] &= PF_USER;
 204                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 205                 }
 206
 207                 INVLPG( Addr & ~0xFFF );
 208                 //LEAVE('-')
 209                 return;
 210         }
 211
 212         // If it was a user, tell the thread handler
 213         if(ErrorCode & 4) {
 214                 Warning("%s %s %s memory%s",
 215                         (ErrorCode&4?"User":"Kernel"),
 216                         (ErrorCode&2?"write to":"read from"),
 217                         (ErrorCode&1?"bad/locked":"non-present"),
 218                         (ErrorCode&16?" (Instruction Fetch)":"")
 219                         );
 220                 Warning("User Pagefault: Instruction at %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 221                 __asm__ __volatile__ ("sti");   // Restart IRQs
 222                 #if 1
 223                 Error_Backtrace(Regs->eip, Regs->ebp);
 224                 #endif
 225                 Threads_SegFault(Addr);
 226                 return ;
 227         }
 228
 229         Debug_KernelPanic();
 230
 231         // -- Check Error Code --
 232         if(ErrorCode & 8)
 233                 Warning("Reserved Bits Trashed!");
 234         else
 235         {
 236                 Warning("%s %s %s memory%s",
 237                         (ErrorCode&4?"User":"Kernel"),
 238                         (ErrorCode&2?"write to":"read from"),
 239                         (ErrorCode&1?"bad/locked":"non-present"),
 240                         (ErrorCode&16?" (Instruction Fetch)":"")
 241                         );
 242         }
 243
 244         Log("Code at %p accessed %p", Regs->eip, Addr);
 245         // Print Stack Backtrace
 246         Error_Backtrace(Regs->eip, Regs->ebp);
 247
 248         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 249         if( gaPageDir[Addr>>22] & PF_PRESENT )
 250                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 251
 252         //MM_DumpTables(0, -1);
 253
 254         // Register Dump
 255         Log("EAX %08x ECX %08x EDX %08x EBX %08x", Regs->eax, Regs->ecx, Regs->edx, Regs->ebx);
 256         Log("ESP %08x EBP %08x ESI %08x EDI %08x", Regs->esp, Regs->ebp, Regs->esi, Regs->edi);
 257         //Log("SS:ESP %04x:%08x", Regs->ss, Regs->esp);
 258         Log("CS:EIP %04x:%08x", Regs->cs, Regs->eip);
 259         Log("DS %04x ES %04x FS %04x GS %04x", Regs->ds, Regs->es, Regs->fs, Regs->gs);
 260         {
 261                 Uint    dr0, dr1;
 262                 __ASM__ ("mov %%dr0, %0":"=r"(dr0):);
 263                 __ASM__ ("mov %%dr1, %0":"=r"(dr1):);
 264                 Log("DR0 %08x DR1 %08x", dr0, dr1);
 265         }
 266
 267         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 268 }
 269
 270 /**
 271  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 272  * \brief Dumps the layout of the page tables
 273  */
 274 void MM_DumpTables(tVAddr Start, tVAddr End)
 275 {
 276         tVAddr  rangeStart = 0;
 277         tPAddr  expected = 0;
 278         tVAddr  curPos;
 279         Uint    page;
 280         const tPAddr    MASK = ~0xF78;
 281
 282         Start >>= 12;   End >>= 12;
 283
 284         #if 0
 285         Log("Directory Entries:");
 286         for(page = Start >> 10;
 287                 page < (End >> 10)+1;
 288                 page ++)
 289         {
 290                 if(gaPageDir[page])
 291                 {
 292                         Log(" 0x%08x-0x%08x :: 0x%08x",
 293                                 page<<22, ((page+1)<<22)-1,
 294                                 gaPageDir[page]&~0xFFF
 295                                 );
 296                 }
 297         }
 298         #endif
 299
 300         Log("Table Entries:");
 301         for(page = Start, curPos = Start<<12;
 302                 page < End;
 303                 curPos += 0x1000, page++)
 304         {
 305                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 306                 ||  !(gaPageTable[page] & PF_PRESENT)
 307                 ||  (gaPageTable[page] & MASK) != expected)
 308                 {
 309                         if(expected) {
 310                                 Log(" 0x%08x => 0x%08x - 0x%08x (%s%s%s%s%s)",
 311                                         rangeStart,
 312                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 313                                         curPos - rangeStart,
 314                                         (expected & PF_NOPAGE ? "P" : "-"),
 315                                         (expected & PF_COW ? "C" : "-"),
 316                                         (expected & PF_GLOBAL ? "G" : "-"),
 317                                         (expected & PF_USER ? "U" : "-"),
 318                                         (expected & PF_WRITE ? "W" : "-"),
 319                                         gaPageTable[page] & MASK, expected
 320                                         );
 321                                 expected = 0;
 322                         }
 323                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 324                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 325
 326                         expected = (gaPageTable[page] & MASK);
 327                         rangeStart = curPos;
 328                 }
 329                 if(expected)    expected += 0x1000;
 330         }
 331
 332         if(expected) {
 333                 Log("0x%08x => 0x%08x - 0x%08x (%s%s%s%s)",
 334                         rangeStart,
 335                         gaPageTable[rangeStart>>12] & ~0xFFF,
 336                         curPos - rangeStart,
 337                         (expected & PF_NOPAGE ? "p" : "-"),
 338                         (expected & PF_COW ? "C" : "-"),
 339                         (expected & PF_USER ? "U" : "-"),
 340                         (expected & PF_WRITE ? "W" : "-")
 341                         );
 342                 expected = 0;
 343         }
 344 }
 345
 346 /**
 347  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 348  */
 349 tPAddr MM_Allocate(tVAddr VAddr)
 350 {
 351         tPAddr  paddr;
 352         //ENTER("xVAddr", VAddr);
 353         //__asm__ __volatile__ ("xchg %bx,%bx");
 354         // Check if the directory is mapped
 355         if( gaPageDir[ VAddr >> 22 ] == 0 )
 356         {
 357                 // Allocate directory
 358                 paddr = MM_AllocPhys();
 359                 //LOG("paddr = 0x%llx (new table)", paddr);
 360                 if( paddr == 0 ) {
 361                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 362                         //LEAVE('i',0);
 363                         return 0;
 364                 }
 365                 // Map
 366                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 367                 // Mark as user
 368                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 369
 370                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 371                 //LOG("Clearing new table");
 372                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 373         }
 374         // Check if the page is already allocated
 375         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 376                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 377                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 378                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 379         }
 380
 381         // Allocate
 382         paddr = MM_AllocPhys();
 383         //LOG("paddr = 0x%llx", paddr);
 384         if( paddr == 0 ) {
 385                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 386                         VAddr, __builtin_return_address(0));
 387                 //LEAVE('i',0);
 388                 return 0;
 389         }
 390         // Map
 391         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 392         // Mark as user
 393         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 394         // Invalidate Cache for address
 395         INVLPG( VAddr & ~0xFFF );
 396
 397         //LEAVE('X', paddr);
 398         return paddr;
 399 }
 400
 401 /**
 402  * \fn void MM_Deallocate(tVAddr VAddr)
 403  */
 404 void MM_Deallocate(tVAddr VAddr)
 405 {
 406         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 407                 Warning("MM_Deallocate - Directory not mapped");
 408                 return;
 409         }
 410
 411         if(gaPageTable[ VAddr >> 12 ] == 0) {
 412                 Warning("MM_Deallocate - Page is not allocated");
 413                 return;
 414         }
 415
 416         // Dereference page
 417         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 418         // Clear page
 419         gaPageTable[ VAddr >> 12 ] = 0;
 420 }
 421
 422 /**
 423  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 424  * \brief Checks if the passed address is accesable
 425  */
 426 tPAddr MM_GetPhysAddr(tVAddr Addr)
 427 {
 428         if( !(gaPageDir[Addr >> 22] & 1) )
 429                 return 0;
 430         if( !(gaPageTable[Addr >> 12] & 1) )
 431                 return 0;
 432         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 433 }
 434
 435 /**
 436  * \fn void MM_SetCR3(Uint CR3)
 437  * \brief Sets the current process space
 438  */
 439 void MM_SetCR3(Uint CR3)
 440 {
 441         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 442 }
 443
 444 /**
 445  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 446  * \brief Map a physical page to a virtual one
 447  */
 448 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 449 {
 450         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 451         // Sanity check
 452         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 453                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 454                 //LEAVE('i', 0);
 455                 return 0;
 456         }
 457
 458         // Align addresses
 459         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 460
 461         // Check if the directory is mapped
 462         if( gaPageDir[ VAddr >> 22 ] == 0 )
 463         {
 464                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 465
 466                 // Mark as user
 467                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 468
 469                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 470                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 471         }
 472         // Check if the page is already allocated
 473         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 474                 Warning("MM_Map - Allocating to used address");
 475                 //LEAVE('i', 0);
 476                 return 0;
 477         }
 478
 479         // Map
 480         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 481         // Mark as user
 482         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 483
 484         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 485         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 486
 487         // Reference
 488         MM_RefPhys( PAddr );
 489
 490         //LOG("INVLPG( 0x%x )", VAddr);
 491         INVLPG( VAddr );
 492
 493         //LEAVE('i', 1);
 494         return 1;
 495 }
 496
 497 /**
 498  * \fn tVAddr MM_ClearUser()
 499  * \brief Clear user's address space
 500  */
 501 tVAddr MM_ClearUser(void)
 502 {
 503         Uint    i, j;
 504
 505         // Copy Directories
 506         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 507         {
 508                 // Check if directory is not allocated
 509                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 510                         gaPageDir[i] = 0;
 511                         continue;
 512                 }
 513
 514
 515                 for( j = 0; j < 1024; j ++ )
 516                 {
 517                         if( gaPageTable[i*1024+j] & 1 )
 518                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 519                         gaPageTable[i*1024+j] = 0;
 520                 }
 521
 522                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 523                 gaPageDir[i] = 0;
 524                 INVLPG( &gaPageTable[i*1024] );
 525         }
 526         INVLPG( gaPageDir );
 527
 528         return *gpPageCR3;
 529 }
 530
 531 /**
 532  * \fn tPAddr MM_Clone(void)
 533  * \brief Clone the current address space
 534  */
 535 tPAddr MM_Clone(void)
 536 {
 537         Uint    i, j;
 538         tVAddr  ret;
 539         Uint    page = 0;
 540         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 541         void    *tmp;
 542
 543         Mutex_Acquire( &glTempFractal );
 544
 545         // Create Directory Table
 546         *gpTmpCR3 = MM_AllocPhys() | 3;
 547         INVLPG( gaTmpDir );
 548         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 549         memsetd( gaTmpDir, 0, 1024 );
 550
 551         if( Threads_GetPID() != 0 )
 552         {
 553                 // Copy Tables
 554                 for( i = 0; i < 768; i ++)
 555                 {
 556                         // Check if table is allocated
 557                         if( !(gaPageDir[i] & PF_PRESENT) ) {
 558                                 gaTmpDir[i] = 0;
 559                                 page += 1024;
 560                                 continue;
 561                         }
 562
 563                         // Allocate new table
 564                         gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 565                         INVLPG( &gaTmpTable[page] );
 566                         // Fill
 567                         for( j = 0; j < 1024; j ++, page++ )
 568                         {
 569                                 if( !(gaPageTable[page] & PF_PRESENT) ) {
 570                                         gaTmpTable[page] = 0;
 571                                         continue;
 572                                 }
 573
 574                                 // Refrence old page
 575                                 MM_RefPhys( gaPageTable[page] & ~0xFFF );
 576                                 // Add to new table
 577                                 if(gaPageTable[page] & PF_WRITE) {
 578                                         gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 579                                         gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 580                                         INVLPG( page << 12 );
 581                                 }
 582                                 else
 583                                         gaTmpTable[page] = gaPageTable[page];
 584                         }
 585                 }
 586         }
 587
 588         // Map in kernel tables (and make fractal mapping)
 589         for( i = 768; i < 1024; i ++ )
 590         {
 591                 // Fractal
 592                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 593                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 594                         continue;
 595                 }
 596
 597                 if( gaPageDir[i] == 0 ) {
 598                         gaTmpDir[i] = 0;
 599                         continue;
 600                 }
 601
 602                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 603                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 604                 gaTmpDir[i] = gaPageDir[i];
 605         }
 606
 607         // Allocate kernel stack
 608         for(i = KERNEL_STACKS >> 22;
 609                 i < KERNEL_STACKS_END >> 22;
 610                 i ++ )
 611         {
 612                 // Check if directory is allocated
 613                 if( (gaPageDir[i] & 1) == 0 ) {
 614                         gaTmpDir[i] = 0;
 615                         continue;
 616                 }
 617
 618                 // We don't care about other kernel stacks, just the current one
 619                 if( i != kStackBase >> 22 ) {
 620                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 621                         gaTmpDir[i] = 0;
 622                         continue;
 623                 }
 624
 625                 // Create a copy
 626                 gaTmpDir[i] = MM_AllocPhys() | 3;
 627                 INVLPG( &gaTmpTable[i*1024] );
 628                 for( j = 0; j < 1024; j ++ )
 629                 {
 630                         // Is the page allocated? If not, skip
 631                         if( !(gaPageTable[i*1024+j] & 1) ) {
 632                                 gaTmpTable[i*1024+j] = 0;
 633                                 continue;
 634                         }
 635
 636                         // We don't care about other kernel stacks
 637                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 638                                 gaTmpTable[i*1024+j] = 0;
 639                                 continue;
 640                         }
 641
 642                         // Allocate page
 643                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 644
 645                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 646
 647                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 648                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 649                         MM_FreeTemp( (Uint)tmp );
 650                 }
 651         }
 652
 653         ret = *gpTmpCR3 & ~0xFFF;
 654         Mutex_Release( &glTempFractal );
 655
 656         //LEAVE('x', ret);
 657         return ret;
 658 }
 659
 660 /**
 661  * \fn tVAddr MM_NewKStack(void)
 662  * \brief Create a new kernel stack
 663  */
 664 tVAddr MM_NewKStack(void)
 665 {
 666         tVAddr  base;
 667         Uint    i;
 668         for(base = KERNEL_STACKS; base < KERNEL_STACKS_END; base += KERNEL_STACK_SIZE)
 669         {
 670                 // Check if space is free
 671                 if(MM_GetPhysAddr(base) != 0)   continue;
 672                 // Allocate
 673                 //for(i = KERNEL_STACK_SIZE; i -= 0x1000 ; )
 674                 for(i = 0; i < KERNEL_STACK_SIZE; i += 0x1000 )
 675                 {
 676                         if( MM_Allocate(base+i) == 0 )
 677                         {
 678                                 // On error, print a warning and return error
 679                                 Warning("MM_NewKStack - Out of memory");
 680                                 // - Clean up
 681                                 //for( i += 0x1000 ; i < KERNEL_STACK_SIZE; i += 0x1000 )
 682                                 //      MM_Deallocate(base+i);
 683                                 return 0;
 684                         }
 685                 }
 686                 // Success
 687                 Log("MM_NewKStack - Allocated %p", base + KERNEL_STACK_SIZE);
 688                 return base+KERNEL_STACK_SIZE;
 689         }
 690         // No stacks left
 691         Warning("MM_NewKStack - No address space left");
 692         return 0;
 693 }
 694
 695 /**
 696  * \fn tVAddr MM_NewWorkerStack()
 697  * \brief Creates a new worker stack
 698  */
 699 tVAddr MM_NewWorkerStack()
 700 {
 701         Uint    esp, ebp;
 702         Uint    oldstack;
 703         Uint    base, addr;
 704          int    i, j;
 705         Uint    *tmpPage;
 706         tPAddr  pages[WORKER_STACK_SIZE>>12];
 707
 708         // Get the old ESP and EBP
 709         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 710         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 711
 712         // TODO: Thread safety
 713         // Find a free worker stack address
 714         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 715         {
 716                 // Used block
 717                 if( gWorkerStacks[base/32] == -1 ) {
 718                         base += 31;     base &= ~31;
 719                         base --;        // Counteracted by the base++
 720                         continue;
 721                 }
 722                 // Used stack
 723                 if( gWorkerStacks[base/32] & (1 << base) ) {
 724                         continue;
 725                 }
 726                 break;
 727         }
 728         if(base >= NUM_WORKER_STACKS) {
 729                 Warning("Uh-oh! Out of worker stacks");
 730                 return 0;
 731         }
 732
 733         // It's ours now!
 734         gWorkerStacks[base/32] |= (1 << base);
 735         // Make life easier for later calls
 736         giLastUsedWorker = base;
 737         // We have one
 738         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 739         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 740
 741         // Acquire the lock for the temp fractal mappings
 742         Mutex_Acquire(&glTempFractal);
 743
 744         // Set the temp fractals to TID0's address space
 745         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 746         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 747         INVLPG( gaTmpDir );
 748
 749
 750         // Check if the directory is mapped (we are assuming that the stacks
 751         // will fit neatly in a directory)
 752         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 753         if(gaTmpDir[ base >> 22 ] == 0) {
 754                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 755                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 756         }
 757
 758         // Mapping Time!
 759         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 760         //for( addr = WORKER_STACK_SIZE; addr; addr -= 0x1000 )
 761         {
 762                 pages[ addr >> 12 ] = MM_AllocPhys();
 763                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 764         }
 765         *gpTmpCR3 = 0;
 766         // Release the temp mapping lock
 767         Mutex_Release(&glTempFractal);
 768
 769         // Copy the old stack
 770         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 771         esp = oldstack - esp;   // ESP as an offset in the stack
 772
 773         // Make `base` be the top of the stack
 774         base += WORKER_STACK_SIZE;
 775
 776         i = (WORKER_STACK_SIZE>>12) - 1;
 777         // Copy the contents of the old stack to the new one, altering the addresses
 778         // `addr` is refering to bytes from the stack base (mem downwards)
 779         for(addr = 0; addr < esp; addr += 0x1000)
 780         {
 781                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 782                 tmpPage = (void*)MM_MapTemp( pages[i] );
 783                 // Copy old stack
 784                 for(j = 0; j < 1024; j++)
 785                 {
 786                         // Possible Stack address?
 787                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 788                                 tmpPage[j] = base - (oldstack - stack[j]);
 789                         else    // Seems not, best leave it alone
 790                                 tmpPage[j] = stack[j];
 791                 }
 792                 MM_FreeTemp((tVAddr)tmpPage);
 793                 i --;
 794         }
 795
 796         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 797         return base;
 798 }
 799
 800 /**
 801  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 802  * \brief Sets the flags on a page
 803  */
 804 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 805 {
 806         tTabEnt *ent;
 807         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 808         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 809
 810         ent = &gaPageTable[VAddr >> 12];
 811
 812         // Read-Only
 813         if( Mask & MM_PFLAG_RO )
 814         {
 815                 if( Flags & MM_PFLAG_RO ) {
 816                         *ent &= ~PF_WRITE;
 817                 }
 818                 else {
 819                         gaPageDir[VAddr >> 22] |= PF_WRITE;
 820                         *ent |= PF_WRITE;
 821                 }
 822         }
 823
 824         // Kernel
 825         if( Mask & MM_PFLAG_KERNEL )
 826         {
 827                 if( Flags & MM_PFLAG_KERNEL ) {
 828                         *ent &= ~PF_USER;
 829                 }
 830                 else {
 831                         gaPageDir[VAddr >> 22] |= PF_USER;
 832                         *ent |= PF_USER;
 833                 }
 834         }
 835
 836         // Copy-On-Write
 837         if( Mask & MM_PFLAG_COW )
 838         {
 839                 if( Flags & MM_PFLAG_COW ) {
 840                         *ent &= ~PF_WRITE;
 841                         *ent |= PF_COW;
 842                 }
 843                 else {
 844                         *ent &= ~PF_COW;
 845                         *ent |= PF_WRITE;
 846                 }
 847         }
 848
 849         //Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
 850         //      *ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 851 }
 852
 853 /**
 854  * \brief Get the flags on a page
 855  */
 856 Uint MM_GetFlags(tVAddr VAddr)
 857 {
 858         tTabEnt *ent;
 859         Uint    ret = 0;
 860
 861         // Validity Check
 862         if( !(gaPageDir[VAddr >> 22] & 1) )     return 0;
 863         if( !(gaPageTable[VAddr >> 12] & 1) )   return 0;
 864
 865         ent = &gaPageTable[VAddr >> 12];
 866
 867         // Read-Only
 868         if( !(*ent & PF_WRITE) )        ret |= MM_PFLAG_RO;
 869         // Kernel
 870         if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
 871         // Copy-On-Write
 872         if( *ent & PF_COW )     ret |= MM_PFLAG_COW;
 873
 874         return ret;
 875 }
 876
 877 /**
 878  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 879  * \brief Duplicates a virtual page to a physical one
 880  */
 881 tPAddr MM_DuplicatePage(tVAddr VAddr)
 882 {
 883         tPAddr  ret;
 884         Uint    temp;
 885          int    wasRO = 0;
 886
 887         //ENTER("xVAddr", VAddr);
 888
 889         // Check if mapped
 890         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 891         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 892
 893         // Page Align
 894         VAddr &= ~0xFFF;
 895
 896         // Allocate new page
 897         ret = MM_AllocPhys();
 898
 899         // Write-lock the page (to keep data constistent), saving its R/W state
 900         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 901         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 902         INVLPG( VAddr );
 903
 904         // Copy Data
 905         temp = MM_MapTemp(ret);
 906         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 907         MM_FreeTemp(temp);
 908
 909         // Restore Writeable status
 910         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 911         INVLPG(VAddr);
 912
 913         //LEAVE('X', ret);
 914         return ret;
 915 }
 916
 917 /**
 918  * \fn Uint MM_MapTemp(tPAddr PAddr)
 919  * \brief Create a temporary memory mapping
 920  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 921  */
 922 tVAddr MM_MapTemp(tPAddr PAddr)
 923 {
 924          int    i;
 925
 926         //ENTER("XPAddr", PAddr);
 927
 928         PAddr &= ~0xFFF;
 929
 930         //LOG("glTempMappings = %i", glTempMappings);
 931
 932         for(;;)
 933         {
 934                 Mutex_Acquire( &glTempMappings );
 935
 936                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 937                 {
 938                         // Check if page used
 939                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 940                         // Mark as used
 941                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 942                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 943                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 944                         Mutex_Release( &glTempMappings );
 945                         return TEMP_MAP_ADDR + (i << 12);
 946                 }
 947                 Mutex_Release( &glTempMappings );
 948                 Threads_Yield();        // TODO: Use a sleep queue here instead
 949         }
 950 }
 951
 952 /**
 953  * \fn void MM_FreeTemp(tVAddr PAddr)
 954  * \brief Free's a temp mapping
 955  */
 956 void MM_FreeTemp(tVAddr VAddr)
 957 {
 958          int    i = VAddr >> 12;
 959         //ENTER("xVAddr", VAddr);
 960
 961         if(i >= (TEMP_MAP_ADDR >> 12))
 962                 gaPageTable[ i ] = 0;
 963
 964         //LEAVE('-');
 965 }
 966
 967 /**
 968  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 969  * \brief Allocates a contigous number of pages
 970  */
 971 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 972 {
 973          int    i, j;
 974
 975         PAddr &= ~0xFFF;
 976
 977         // Scan List
 978         for( i = 0; i < NUM_HW_PAGES; i ++ )
 979         {
 980                 // Check if addr used
 981                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 982                         continue;
 983
 984                 // Check possible region
 985                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 986                 {
 987                         // If there is an allocated page in the region we are testing, break
 988                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 989                 }
 990                 // Is it all free?
 991                 if( j == Number )
 992                 {
 993                         // Allocate
 994                         for( j = 0; j < Number; j++ ) {
 995                                 MM_RefPhys( PAddr + (j<<12) );
 996                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 997                         }
 998                         return HW_MAP_ADDR + (i<<12);
 999                 }
1000         }
1001         // If we don't find any, return NULL
1002         return 0;
1003 }
1004
1005 /**
1006  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
1007  * \brief Allocates DMA physical memory
1008  * \param Pages Number of pages required
1009  * \param MaxBits       Maximum number of bits the physical address can have
1010  * \param PhysAddr      Pointer to the location to place the physical address allocated
1011  * \return Virtual address allocate
1012  */
1013 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
1014 {
1015         tPAddr  maxCheck = (1 << MaxBits);
1016         tPAddr  phys;
1017         tVAddr  ret;
1018
1019         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
1020
1021         // Sanity Check
1022         if(MaxBits < 12 || !PhysAddr) {
1023                 LEAVE('i', 0);
1024                 return 0;
1025         }
1026
1027         // Bound
1028         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
1029
1030         // Fast Allocate
1031         if(Pages == 1 && MaxBits >= PHYS_BITS)
1032         {
1033                 phys = MM_AllocPhys();
1034                 *PhysAddr = phys;
1035                 ret = MM_MapHWPages(phys, 1);
1036                 if(ret == 0) {
1037                         MM_DerefPhys(phys);
1038                         LEAVE('i', 0);
1039                         return 0;
1040                 }
1041                 LEAVE('x', ret);
1042                 return ret;
1043         }
1044
1045         // Slow Allocate
1046         phys = MM_AllocPhysRange(Pages, MaxBits);
1047         // - Was it allocated?
1048         if(phys == 0) {
1049                 LEAVE('i', 0);
1050                 return 0;
1051         }
1052
1053         // Allocated successfully, now map
1054         ret = MM_MapHWPages(phys, Pages);
1055         if( ret == 0 ) {
1056                 // If it didn't map, free then return 0
1057                 for(;Pages--;phys+=0x1000)
1058                         MM_DerefPhys(phys);
1059                 LEAVE('i', 0);
1060                 return 0;
1061         }
1062
1063         *PhysAddr = phys;
1064         LEAVE('x', ret);
1065         return ret;
1066 }
1067
1068 /**
1069  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1070  * \brief Unmap a hardware page
1071  */
1072 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1073 {
1074          int    i, j;
1075
1076         //Log_Debug("VirtMem", "MM_UnmapHWPages: (VAddr=0x%08x, Number=%i)", VAddr, Number);
1077
1078         // Sanity Check
1079         if(VAddr < HW_MAP_ADDR || VAddr+Number*0x1000 > HW_MAP_MAX)     return;
1080
1081         i = VAddr >> 12;
1082
1083         Mutex_Acquire( &glTempMappings );       // Temp and HW share a directory, so they share a lock
1084
1085         for( j = 0; j < Number; j++ )
1086         {
1087                 MM_DerefPhys( gaPageTable[ i + j ] & ~0xFFF );
1088                 gaPageTable[ i + j ] = 0;
1089         }
1090
1091         Mutex_Release( &glTempMappings );
1092 }
1093
1094 // --- EXPORTS ---
1095 EXPORT(MM_GetPhysAddr);
1096 EXPORT(MM_Map);
1097 //EXPORT(MM_Unmap);
1098 EXPORT(MM_MapHWPages);
1099 EXPORT(MM_AllocDMA);
1100 EXPORT(MM_UnmapHWPages);