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_NOPAGE       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 tMutex  glTempMappings;
  99 tMutex  glTempFractal;
 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                 Uint    dr0, dr1;
 257                 __ASM__ ("mov %%dr0, %0":"=r"(dr0):);
 258                 __ASM__ ("mov %%dr1, %0":"=r"(dr1):);
 259                 Log("DR0 %08x DR1 %08x", dr0, dr1);
 260         }
 261
 262         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 263 }
 264
 265 /**
 266  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 267  * \brief Dumps the layout of the page tables
 268  */
 269 void MM_DumpTables(tVAddr Start, tVAddr End)
 270 {
 271         tVAddr  rangeStart = 0;
 272         tPAddr  expected = 0;
 273         tVAddr  curPos;
 274         Uint    page;
 275         const tPAddr    MASK = ~0xF98;
 276
 277         Start >>= 12;   End >>= 12;
 278
 279         #if 0
 280         Log("Directory Entries:");
 281         for(page = Start >> 10;
 282                 page < (End >> 10)+1;
 283                 page ++)
 284         {
 285                 if(gaPageDir[page])
 286                 {
 287                         Log(" 0x%08x-0x%08x :: 0x%08x",
 288                                 page<<22, ((page+1)<<22)-1,
 289                                 gaPageDir[page]&~0xFFF
 290                                 );
 291                 }
 292         }
 293         #endif
 294
 295         Log("Table Entries:");
 296         for(page = Start, curPos = Start<<12;
 297                 page < End;
 298                 curPos += 0x1000, page++)
 299         {
 300                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 301                 ||  !(gaPageTable[page] & PF_PRESENT)
 302                 ||  (gaPageTable[page] & MASK) != expected)
 303                 {
 304                         if(expected) {
 305                                 Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 306                                         rangeStart, curPos - 1,
 307                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 308                                         (expected & ~0xFFF) - 1,
 309                                         (expected & PF_NOPAGE ? "P" : "-"),
 310                                         (expected & PF_COW ? "C" : "-"),
 311                                         (expected & PF_USER ? "U" : "-"),
 312                                         (expected & PF_WRITE ? "W" : "-")
 313                                         );
 314                                 expected = 0;
 315                         }
 316                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 317                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 318
 319                         expected = (gaPageTable[page] & MASK);
 320                         rangeStart = curPos;
 321                 }
 322                 if(expected)    expected += 0x1000;
 323         }
 324
 325         if(expected) {
 326                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 327                         rangeStart, curPos - 1,
 328                         gaPageTable[rangeStart>>12] & ~0xFFF,
 329                         (expected & ~0xFFF) - 1,
 330                         (expected & PF_NOPAGE ? "p" : "-"),
 331                         (expected & PF_COW ? "C" : "-"),
 332                         (expected & PF_USER ? "U" : "-"),
 333                         (expected & PF_WRITE ? "W" : "-")
 334                         );
 335                 expected = 0;
 336         }
 337 }
 338
 339 /**
 340  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 341  */
 342 tPAddr MM_Allocate(tVAddr VAddr)
 343 {
 344         tPAddr  paddr;
 345         //ENTER("xVAddr", VAddr);
 346         //__asm__ __volatile__ ("xchg %bx,%bx");
 347         // Check if the directory is mapped
 348         if( gaPageDir[ VAddr >> 22 ] == 0 )
 349         {
 350                 // Allocate directory
 351                 paddr = MM_AllocPhys();
 352                 //LOG("paddr = 0x%llx (new table)", paddr);
 353                 if( paddr == 0 ) {
 354                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 355                         //LEAVE('i',0);
 356                         return 0;
 357                 }
 358                 // Map
 359                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 360                 // Mark as user
 361                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 362
 363                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 364                 //LOG("Clearing new table");
 365                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 366         }
 367         // Check if the page is already allocated
 368         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 369                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 370                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 371                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 372         }
 373
 374         // Allocate
 375         paddr = MM_AllocPhys();
 376         //LOG("paddr = 0x%llx", paddr);
 377         if( paddr == 0 ) {
 378                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 379                         VAddr, __builtin_return_address(0));
 380                 //LEAVE('i',0);
 381                 return 0;
 382         }
 383         // Map
 384         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 385         // Mark as user
 386         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 387         // Invalidate Cache for address
 388         INVLPG( VAddr & ~0xFFF );
 389
 390         //LEAVE('X', paddr);
 391         return paddr;
 392 }
 393
 394 /**
 395  * \fn void MM_Deallocate(tVAddr VAddr)
 396  */
 397 void MM_Deallocate(tVAddr VAddr)
 398 {
 399         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 400                 Warning("MM_Deallocate - Directory not mapped");
 401                 return;
 402         }
 403
 404         if(gaPageTable[ VAddr >> 12 ] == 0) {
 405                 Warning("MM_Deallocate - Page is not allocated");
 406                 return;
 407         }
 408
 409         // Dereference page
 410         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 411         // Clear page
 412         gaPageTable[ VAddr >> 12 ] = 0;
 413 }
 414
 415 /**
 416  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 417  * \brief Checks if the passed address is accesable
 418  */
 419 tPAddr MM_GetPhysAddr(tVAddr Addr)
 420 {
 421         if( !(gaPageDir[Addr >> 22] & 1) )
 422                 return 0;
 423         if( !(gaPageTable[Addr >> 12] & 1) )
 424                 return 0;
 425         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 426 }
 427
 428 /**
 429  * \fn void MM_SetCR3(Uint CR3)
 430  * \brief Sets the current process space
 431  */
 432 void MM_SetCR3(Uint CR3)
 433 {
 434         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 435 }
 436
 437 /**
 438  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 439  * \brief Map a physical page to a virtual one
 440  */
 441 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 442 {
 443         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 444         // Sanity check
 445         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 446                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 447                 //LEAVE('i', 0);
 448                 return 0;
 449         }
 450
 451         // Align addresses
 452         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 453
 454         // Check if the directory is mapped
 455         if( gaPageDir[ VAddr >> 22 ] == 0 )
 456         {
 457                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 458
 459                 // Mark as user
 460                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 461
 462                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 463                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 464         }
 465         // Check if the page is already allocated
 466         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 467                 Warning("MM_Map - Allocating to used address");
 468                 //LEAVE('i', 0);
 469                 return 0;
 470         }
 471
 472         // Map
 473         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 474         // Mark as user
 475         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 476
 477         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 478         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 479
 480         // Reference
 481         MM_RefPhys( PAddr );
 482
 483         //LOG("INVLPG( 0x%x )", VAddr);
 484         INVLPG( VAddr );
 485
 486         //LEAVE('i', 1);
 487         return 1;
 488 }
 489
 490 /**
 491  * \fn tVAddr MM_ClearUser()
 492  * \brief Clear user's address space
 493  */
 494 tVAddr MM_ClearUser(void)
 495 {
 496         Uint    i, j;
 497
 498         // Copy Directories
 499         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 500         {
 501                 // Check if directory is not allocated
 502                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 503                         gaPageDir[i] = 0;
 504                         continue;
 505                 }
 506
 507
 508                 for( j = 0; j < 1024; j ++ )
 509                 {
 510                         if( gaPageTable[i*1024+j] & 1 )
 511                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 512                         gaPageTable[i*1024+j] = 0;
 513                 }
 514
 515                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 516                 gaPageDir[i] = 0;
 517                 INVLPG( &gaPageTable[i*1024] );
 518         }
 519         INVLPG( gaPageDir );
 520
 521         return *gpPageCR3;
 522 }
 523
 524 /**
 525  * \fn tPAddr MM_Clone(void)
 526  * \brief Clone the current address space
 527  */
 528 tPAddr MM_Clone(void)
 529 {
 530         Uint    i, j;
 531         tVAddr  ret;
 532         Uint    page = 0;
 533         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 534         void    *tmp;
 535
 536         Mutex_Acquire( &glTempFractal );
 537
 538         // Create Directory Table
 539         *gpTmpCR3 = MM_AllocPhys() | 3;
 540         INVLPG( gaTmpDir );
 541         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 542         memsetd( gaTmpDir, 0, 1024 );
 543
 544         if( Threads_GetPID() != 0 )
 545         {
 546                 // Copy Tables
 547                 for( i = 0; i < 768; i ++)
 548                 {
 549                         // Check if table is allocated
 550                         if( !(gaPageDir[i] & PF_PRESENT) ) {
 551                                 gaTmpDir[i] = 0;
 552                                 page += 1024;
 553                                 continue;
 554                         }
 555
 556                         // Allocate new table
 557                         gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 558                         INVLPG( &gaTmpTable[page] );
 559                         // Fill
 560                         for( j = 0; j < 1024; j ++, page++ )
 561                         {
 562                                 if( !(gaPageTable[page] & PF_PRESENT) ) {
 563                                         gaTmpTable[page] = 0;
 564                                         continue;
 565                                 }
 566
 567                                 // Refrence old page
 568                                 MM_RefPhys( gaPageTable[page] & ~0xFFF );
 569                                 // Add to new table
 570                                 if(gaPageTable[page] & PF_WRITE) {
 571                                         gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 572                                         gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 573                                         INVLPG( page << 12 );
 574                                 }
 575                                 else
 576                                         gaTmpTable[page] = gaPageTable[page];
 577                         }
 578                 }
 579         }
 580
 581         // Map in kernel tables (and make fractal mapping)
 582         for( i = 768; i < 1024; i ++ )
 583         {
 584                 // Fractal
 585                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 586                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 587                         continue;
 588                 }
 589
 590                 if( gaPageDir[i] == 0 ) {
 591                         gaTmpDir[i] = 0;
 592                         continue;
 593                 }
 594
 595                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 596                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 597                 gaTmpDir[i] = gaPageDir[i];
 598         }
 599
 600         // Allocate kernel stack
 601         for(i = KERNEL_STACKS >> 22;
 602                 i < KERNEL_STACKS_END >> 22;
 603                 i ++ )
 604         {
 605                 // Check if directory is allocated
 606                 if( (gaPageDir[i] & 1) == 0 ) {
 607                         gaTmpDir[i] = 0;
 608                         continue;
 609                 }
 610
 611                 // We don't care about other kernel stacks, just the current one
 612                 if( i != kStackBase >> 22 ) {
 613                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 614                         gaTmpDir[i] = 0;
 615                         continue;
 616                 }
 617
 618                 // Create a copy
 619                 gaTmpDir[i] = MM_AllocPhys() | 3;
 620                 INVLPG( &gaTmpTable[i*1024] );
 621                 for( j = 0; j < 1024; j ++ )
 622                 {
 623                         // Is the page allocated? If not, skip
 624                         if( !(gaPageTable[i*1024+j] & 1) ) {
 625                                 gaTmpTable[i*1024+j] = 0;
 626                                 continue;
 627                         }
 628
 629                         // We don't care about other kernel stacks
 630                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 631                                 gaTmpTable[i*1024+j] = 0;
 632                                 continue;
 633                         }
 634
 635                         // Allocate page
 636                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 637
 638                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 639
 640                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 641                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 642                         MM_FreeTemp( (Uint)tmp );
 643                 }
 644         }
 645
 646         ret = *gpTmpCR3 & ~0xFFF;
 647         Mutex_Release( &glTempFractal );
 648
 649         //LEAVE('x', ret);
 650         return ret;
 651 }
 652
 653 /**
 654  * \fn tVAddr MM_NewKStack(void)
 655  * \brief Create a new kernel stack
 656  */
 657 tVAddr MM_NewKStack(void)
 658 {
 659         tVAddr  base;
 660         Uint    i;
 661         for(base = KERNEL_STACKS; base < KERNEL_STACKS_END; base += KERNEL_STACK_SIZE)
 662         {
 663                 if(MM_GetPhysAddr(base) != 0)   continue;
 664                 for(i = 0; i < KERNEL_STACK_SIZE; i += 0x1000) {
 665                         MM_Allocate(base+i);
 666                 }
 667                 Log("MM_NewKStack - Allocated %p", base + KERNEL_STACK_SIZE);
 668                 return base+KERNEL_STACK_SIZE;
 669         }
 670         Warning("MM_NewKStack - No address space left\n");
 671         return 0;
 672 }
 673
 674 /**
 675  * \fn tVAddr MM_NewWorkerStack()
 676  * \brief Creates a new worker stack
 677  */
 678 tVAddr MM_NewWorkerStack()
 679 {
 680         Uint    esp, ebp;
 681         Uint    oldstack;
 682         Uint    base, addr;
 683          int    i, j;
 684         Uint    *tmpPage;
 685         tPAddr  pages[WORKER_STACK_SIZE>>12];
 686
 687         // Get the old ESP and EBP
 688         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 689         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 690
 691         // TODO: Thread safety
 692         // Find a free worker stack address
 693         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 694         {
 695                 // Used block
 696                 if( gWorkerStacks[base/32] == -1 ) {
 697                         base += 31;     base &= ~31;
 698                         base --;        // Counteracted by the base++
 699                         continue;
 700                 }
 701                 // Used stack
 702                 if( gWorkerStacks[base/32] & (1 << base) ) {
 703                         continue;
 704                 }
 705                 break;
 706         }
 707         if(base >= NUM_WORKER_STACKS) {
 708                 Warning("Uh-oh! Out of worker stacks");
 709                 return 0;
 710         }
 711
 712         // It's ours now!
 713         gWorkerStacks[base/32] |= (1 << base);
 714         // Make life easier for later calls
 715         giLastUsedWorker = base;
 716         // We have one
 717         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 718         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 719
 720         // Acquire the lock for the temp fractal mappings
 721         Mutex_Acquire(&glTempFractal);
 722
 723         // Set the temp fractals to TID0's address space
 724         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 725         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 726         INVLPG( gaTmpDir );
 727
 728
 729         // Check if the directory is mapped (we are assuming that the stacks
 730         // will fit neatly in a directory)
 731         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 732         if(gaTmpDir[ base >> 22 ] == 0) {
 733                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 734                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 735         }
 736
 737         // Mapping Time!
 738         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 739         //for( addr = WORKER_STACK_SIZE; addr; addr -= 0x1000 )
 740         {
 741                 pages[ addr >> 12 ] = MM_AllocPhys();
 742                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 743         }
 744         *gpTmpCR3 = 0;
 745         // Release the temp mapping lock
 746         Mutex_Release(&glTempFractal);
 747
 748         // Copy the old stack
 749         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 750         esp = oldstack - esp;   // ESP as an offset in the stack
 751
 752         // Make `base` be the top of the stack
 753         base += WORKER_STACK_SIZE;
 754
 755         i = (WORKER_STACK_SIZE>>12) - 1;
 756         // Copy the contents of the old stack to the new one, altering the addresses
 757         // `addr` is refering to bytes from the stack base (mem downwards)
 758         for(addr = 0; addr < esp; addr += 0x1000)
 759         {
 760                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 761                 tmpPage = (void*)MM_MapTemp( pages[i] );
 762                 // Copy old stack
 763                 for(j = 0; j < 1024; j++)
 764                 {
 765                         // Possible Stack address?
 766                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 767                                 tmpPage[j] = base - (oldstack - stack[j]);
 768                         else    // Seems not, best leave it alone
 769                                 tmpPage[j] = stack[j];
 770                 }
 771                 MM_FreeTemp((tVAddr)tmpPage);
 772                 i --;
 773         }
 774
 775         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 776         return base;
 777 }
 778
 779 /**
 780  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 781  * \brief Sets the flags on a page
 782  */
 783 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 784 {
 785         tTabEnt *ent;
 786         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 787         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 788
 789         ent = &gaPageTable[VAddr >> 12];
 790
 791         // Read-Only
 792         if( Mask & MM_PFLAG_RO )
 793         {
 794                 if( Flags & MM_PFLAG_RO ) {
 795                         *ent &= ~PF_WRITE;
 796                 }
 797                 else {
 798                         gaPageDir[VAddr >> 22] |= PF_WRITE;
 799                         *ent |= PF_WRITE;
 800                 }
 801         }
 802
 803         // Kernel
 804         if( Mask & MM_PFLAG_KERNEL )
 805         {
 806                 if( Flags & MM_PFLAG_KERNEL ) {
 807                         *ent &= ~PF_USER;
 808                 }
 809                 else {
 810                         gaPageDir[VAddr >> 22] |= PF_USER;
 811                         *ent |= PF_USER;
 812                 }
 813         }
 814
 815         // Copy-On-Write
 816         if( Mask & MM_PFLAG_COW )
 817         {
 818                 if( Flags & MM_PFLAG_COW ) {
 819                         *ent &= ~PF_WRITE;
 820                         *ent |= PF_COW;
 821                 }
 822                 else {
 823                         *ent &= ~PF_COW;
 824                         *ent |= PF_WRITE;
 825                 }
 826         }
 827
 828         //Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
 829         //      *ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 830 }
 831
 832 /**
 833  * \brief Get the flags on a page
 834  */
 835 Uint MM_GetFlags(tVAddr VAddr)
 836 {
 837         tTabEnt *ent;
 838         Uint    ret = 0;
 839
 840         // Validity Check
 841         if( !(gaPageDir[VAddr >> 22] & 1) )     return 0;
 842         if( !(gaPageTable[VAddr >> 12] & 1) )   return 0;
 843
 844         ent = &gaPageTable[VAddr >> 12];
 845
 846         // Read-Only
 847         if( !(*ent & PF_WRITE) )        ret |= MM_PFLAG_RO;
 848         // Kernel
 849         if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
 850         // Copy-On-Write
 851         if( *ent & PF_COW )     ret |= MM_PFLAG_COW;
 852
 853         return ret;
 854 }
 855
 856 /**
 857  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 858  * \brief Duplicates a virtual page to a physical one
 859  */
 860 tPAddr MM_DuplicatePage(tVAddr VAddr)
 861 {
 862         tPAddr  ret;
 863         Uint    temp;
 864          int    wasRO = 0;
 865
 866         //ENTER("xVAddr", VAddr);
 867
 868         // Check if mapped
 869         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 870         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 871
 872         // Page Align
 873         VAddr &= ~0xFFF;
 874
 875         // Allocate new page
 876         ret = MM_AllocPhys();
 877
 878         // Write-lock the page (to keep data constistent), saving its R/W state
 879         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 880         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 881         INVLPG( VAddr );
 882
 883         // Copy Data
 884         temp = MM_MapTemp(ret);
 885         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 886         MM_FreeTemp(temp);
 887
 888         // Restore Writeable status
 889         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 890         INVLPG(VAddr);
 891
 892         //LEAVE('X', ret);
 893         return ret;
 894 }
 895
 896 /**
 897  * \fn Uint MM_MapTemp(tPAddr PAddr)
 898  * \brief Create a temporary memory mapping
 899  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 900  */
 901 tVAddr MM_MapTemp(tPAddr PAddr)
 902 {
 903          int    i;
 904
 905         //ENTER("XPAddr", PAddr);
 906
 907         PAddr &= ~0xFFF;
 908
 909         //LOG("glTempMappings = %i", glTempMappings);
 910
 911         for(;;)
 912         {
 913                 Mutex_Acquire( &glTempMappings );
 914
 915                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 916                 {
 917                         // Check if page used
 918                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 919                         // Mark as used
 920                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 921                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 922                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 923                         Mutex_Release( &glTempMappings );
 924                         return TEMP_MAP_ADDR + (i << 12);
 925                 }
 926                 Mutex_Release( &glTempMappings );
 927                 Threads_Yield();        // TODO: Use a sleep queue here instead
 928         }
 929 }
 930
 931 /**
 932  * \fn void MM_FreeTemp(tVAddr PAddr)
 933  * \brief Free's a temp mapping
 934  */
 935 void MM_FreeTemp(tVAddr VAddr)
 936 {
 937          int    i = VAddr >> 12;
 938         //ENTER("xVAddr", VAddr);
 939
 940         if(i >= (TEMP_MAP_ADDR >> 12))
 941                 gaPageTable[ i ] = 0;
 942
 943         //LEAVE('-');
 944 }
 945
 946 /**
 947  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 948  * \brief Allocates a contigous number of pages
 949  */
 950 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 951 {
 952          int    i, j;
 953
 954         PAddr &= ~0xFFF;
 955
 956         // Scan List
 957         for( i = 0; i < NUM_HW_PAGES; i ++ )
 958         {
 959                 // Check if addr used
 960                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 961                         continue;
 962
 963                 // Check possible region
 964                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 965                 {
 966                         // If there is an allocated page in the region we are testing, break
 967                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 968                 }
 969                 // Is it all free?
 970                 if( j == Number )
 971                 {
 972                         // Allocate
 973                         for( j = 0; j < Number; j++ ) {
 974                                 MM_RefPhys( PAddr + (j<<12) );
 975                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 976                         }
 977                         return HW_MAP_ADDR + (i<<12);
 978                 }
 979         }
 980         // If we don't find any, return NULL
 981         return 0;
 982 }
 983
 984 /**
 985  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 986  * \brief Allocates DMA physical memory
 987  * \param Pages Number of pages required
 988  * \param MaxBits       Maximum number of bits the physical address can have
 989  * \param PhysAddr      Pointer to the location to place the physical address allocated
 990  * \return Virtual address allocate
 991  */
 992 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 993 {
 994         tPAddr  maxCheck = (1 << MaxBits);
 995         tPAddr  phys;
 996         tVAddr  ret;
 997
 998         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
 999
1000         // Sanity Check
1001         if(MaxBits < 12 || !PhysAddr) {
1002                 LEAVE('i', 0);
1003                 return 0;
1004         }
1005
1006         // Bound
1007         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
1008
1009         // Fast Allocate
1010         if(Pages == 1 && MaxBits >= PHYS_BITS)
1011         {
1012                 phys = MM_AllocPhys();
1013                 *PhysAddr = phys;
1014                 ret = MM_MapHWPages(phys, 1);
1015                 if(ret == 0) {
1016                         MM_DerefPhys(phys);
1017                         LEAVE('i', 0);
1018                         return 0;
1019                 }
1020                 LEAVE('x', ret);
1021                 return ret;
1022         }
1023
1024         // Slow Allocate
1025         phys = MM_AllocPhysRange(Pages, MaxBits);
1026         // - Was it allocated?
1027         if(phys == 0) {
1028                 LEAVE('i', 0);
1029                 return 0;
1030         }
1031
1032         // Allocated successfully, now map
1033         ret = MM_MapHWPages(phys, Pages);
1034         if( ret == 0 ) {
1035                 // If it didn't map, free then return 0
1036                 for(;Pages--;phys+=0x1000)
1037                         MM_DerefPhys(phys);
1038                 LEAVE('i', 0);
1039                 return 0;
1040         }
1041
1042         *PhysAddr = phys;
1043         LEAVE('x', ret);
1044         return ret;
1045 }
1046
1047 /**
1048  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1049  * \brief Unmap a hardware page
1050  */
1051 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1052 {
1053          int    i, j;
1054
1055         //Log_Debug("VirtMem", "MM_UnmapHWPages: (VAddr=0x%08x, Number=%i)", VAddr, Number);
1056
1057         // Sanity Check
1058         if(VAddr < HW_MAP_ADDR || VAddr+Number*0x1000 > HW_MAP_MAX)     return;
1059
1060         i = VAddr >> 12;
1061
1062         Mutex_Acquire( &glTempMappings );       // Temp and HW share a directory, so they share a lock
1063
1064         for( j = 0; j < Number; j++ )
1065         {
1066                 MM_DerefPhys( gaPageTable[ i + j ] & ~0xFFF );
1067                 gaPageTable[ i + j ] = 0;
1068         }
1069
1070         Mutex_Release( &glTempMappings );
1071 }
1072
1073 // --- EXPORTS ---
1074 EXPORT(MM_GetPhysAddr);
1075 EXPORT(MM_Map);
1076 //EXPORT(MM_Unmap);
1077 EXPORT(MM_MapHWPages);
1078 EXPORT(MM_AllocDMA);
1079 EXPORT(MM_UnmapHWPages);