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 tVAddr  MM_ClearUser(void);
  82 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  83
  84 // === GLOBALS ===
  85 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  86 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  87 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  88 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  89 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  90 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  91
  92 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  93 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  94 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  95 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  96 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  97 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  98  int    gbUsePAE = 0;
  99 tMutex  glTempMappings;
 100 tMutex  glTempFractal;
 101 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
 102  int    giLastUsedWorker = 0;
 103
 104 // === CODE ===
 105 /**
 106  * \fn void MM_PreinitVirtual(void)
 107  * \brief Maps the fractal mappings
 108  */
 109 void MM_PreinitVirtual(void)
 110 {
 111         #if USE_PAE
 112         gaInitPageDir[ ((PAGE_TABLE_ADDR >> TAB)-3*512+3)*2 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 113         #else
 114         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 115         #endif
 116         INVLPG( PAGE_TABLE_ADDR );
 117 }
 118
 119 /**
 120  * \fn void MM_InstallVirtual(void)
 121  * \brief Sets up the constant page mappings
 122  */
 123 void MM_InstallVirtual(void)
 124 {
 125          int    i;
 126
 127         #if USE_PAE
 128         // --- Pre-Allocate kernel tables
 129         for( i = KERNEL_BASE >> TAB; i < 1024*4; i ++ )
 130         {
 131                 if( gaPAE_PageDir[ i ] )        continue;
 132
 133                 // Skip stack tables, they are process unique
 134                 if( i > KERNEL_STACKS >> TAB && i < KERNEL_STACKS_END >> TAB) {
 135                         gaPAE_PageDir[ i ] = 0;
 136                         continue;
 137                 }
 138                 // Preallocate table
 139                 gaPAE_PageDir[ i ] = MM_AllocPhys() | 3;
 140                 INVLPG( &gaPAE_PageTable[i*512] );
 141                 memset( &gaPAE_PageTable[i*512], 0, 0x1000 );
 142         }
 143         #else
 144         // --- Pre-Allocate kernel tables
 145         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 146         {
 147                 if( gaPageDir[ i ] )    continue;
 148                 // Skip stack tables, they are process unique
 149                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 150                         gaPageDir[ i ] = 0;
 151                         continue;
 152                 }
 153                 // Preallocate table
 154                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 155                 INVLPG( &gaPageTable[i*1024] );
 156                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 157         }
 158         #endif
 159
 160         // Unset kernel on the User Text pages
 161         for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
 162                 MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
 163         }
 164 }
 165
 166 /**
 167  * \brief Cleans up the SMP required mappings
 168  */
 169 void MM_FinishVirtualInit(void)
 170 {
 171         #if USE_PAE
 172         gaInitPDPT[ 0 ] = 0;
 173         #else
 174         gaInitPageDir[ 0 ] = 0;
 175         #endif
 176 }
 177
 178 /**
 179  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 180  * \brief Called on a page fault
 181  */
 182 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 183 {
 184         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 185
 186         // -- Check for COW --
 187         if( gaPageDir  [Addr>>22] & PF_PRESENT
 188          && gaPageTable[Addr>>12] & PF_PRESENT
 189          && gaPageTable[Addr>>12] & PF_COW )
 190         {
 191                 tPAddr  paddr;
 192                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 193                 {
 194                         gaPageTable[Addr>>12] &= ~PF_COW;
 195                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 196                 }
 197                 else
 198                 {
 199                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 200                         paddr = MM_DuplicatePage( Addr );
 201                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 202                         gaPageTable[Addr>>12] &= PF_USER;
 203                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 204                 }
 205
 206                 INVLPG( Addr & ~0xFFF );
 207                 //LEAVE('-')
 208                 return;
 209         }
 210
 211         // If it was a user, tell the thread handler
 212         if(ErrorCode & 4) {
 213                 Warning("%s %s %s memory%s",
 214                         (ErrorCode&4?"User":"Kernel"),
 215                         (ErrorCode&2?"write to":"read from"),
 216                         (ErrorCode&1?"bad/locked":"non-present"),
 217                         (ErrorCode&16?" (Instruction Fetch)":"")
 218                         );
 219                 Warning("User Pagefault: Instruction at %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 220                 __asm__ __volatile__ ("sti");   // Restart IRQs
 221                 #if 1
 222                 Error_Backtrace(Regs->eip, Regs->ebp);
 223                 #endif
 224                 Threads_SegFault(Addr);
 225                 return ;
 226         }
 227
 228         Debug_KernelPanic();
 229
 230         // -- Check Error Code --
 231         if(ErrorCode & 8)
 232                 Warning("Reserved Bits Trashed!");
 233         else
 234         {
 235                 Warning("%s %s %s memory%s",
 236                         (ErrorCode&4?"User":"Kernel"),
 237                         (ErrorCode&2?"write to":"read from"),
 238                         (ErrorCode&1?"bad/locked":"non-present"),
 239                         (ErrorCode&16?" (Instruction Fetch)":"")
 240                         );
 241         }
 242
 243         Log("Code at %p accessed %p", Regs->eip, Addr);
 244         // Print Stack Backtrace
 245         Error_Backtrace(Regs->eip, Regs->ebp);
 246
 247         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 248         if( gaPageDir[Addr>>22] & PF_PRESENT )
 249                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 250
 251         //MM_DumpTables(0, -1);
 252
 253         // Register Dump
 254         Log("EAX %08x ECX %08x EDX %08x EBX %08x", Regs->eax, Regs->ecx, Regs->edx, Regs->ebx);
 255         Log("ESP %08x EBP %08x ESI %08x EDI %08x", Regs->esp, Regs->ebp, Regs->esi, Regs->edi);
 256         //Log("SS:ESP %04x:%08x", Regs->ss, Regs->esp);
 257         Log("CS:EIP %04x:%08x", Regs->cs, Regs->eip);
 258         Log("DS %04x ES %04x FS %04x GS %04x", Regs->ds, Regs->es, Regs->fs, Regs->gs);
 259         {
 260                 Uint    dr0, dr1;
 261                 __ASM__ ("mov %%dr0, %0":"=r"(dr0):);
 262                 __ASM__ ("mov %%dr1, %0":"=r"(dr1):);
 263                 Log("DR0 %08x DR1 %08x", dr0, dr1);
 264         }
 265
 266         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 267 }
 268
 269 /**
 270  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 271  * \brief Dumps the layout of the page tables
 272  */
 273 void MM_DumpTables(tVAddr Start, tVAddr End)
 274 {
 275         tVAddr  rangeStart = 0;
 276         tPAddr  expected = 0;
 277         tVAddr  curPos;
 278         Uint    page;
 279         const tPAddr    MASK = ~0xF98;
 280
 281         Start >>= 12;   End >>= 12;
 282
 283         #if 0
 284         Log("Directory Entries:");
 285         for(page = Start >> 10;
 286                 page < (End >> 10)+1;
 287                 page ++)
 288         {
 289                 if(gaPageDir[page])
 290                 {
 291                         Log(" 0x%08x-0x%08x :: 0x%08x",
 292                                 page<<22, ((page+1)<<22)-1,
 293                                 gaPageDir[page]&~0xFFF
 294                                 );
 295                 }
 296         }
 297         #endif
 298
 299         Log("Table Entries:");
 300         for(page = Start, curPos = Start<<12;
 301                 page < End;
 302                 curPos += 0x1000, page++)
 303         {
 304                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 305                 ||  !(gaPageTable[page] & PF_PRESENT)
 306                 ||  (gaPageTable[page] & MASK) != expected)
 307                 {
 308                         if(expected) {
 309                                 Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 310                                         rangeStart, curPos - 1,
 311                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 312                                         (expected & ~0xFFF) - 1,
 313                                         (expected & PF_NOPAGE ? "P" : "-"),
 314                                         (expected & PF_COW ? "C" : "-"),
 315                                         (expected & PF_USER ? "U" : "-"),
 316                                         (expected & PF_WRITE ? "W" : "-")
 317                                         );
 318                                 expected = 0;
 319                         }
 320                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 321                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 322
 323                         expected = (gaPageTable[page] & MASK);
 324                         rangeStart = curPos;
 325                 }
 326                 if(expected)    expected += 0x1000;
 327         }
 328
 329         if(expected) {
 330                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 331                         rangeStart, curPos - 1,
 332                         gaPageTable[rangeStart>>12] & ~0xFFF,
 333                         (expected & ~0xFFF) - 1,
 334                         (expected & PF_NOPAGE ? "p" : "-"),
 335                         (expected & PF_COW ? "C" : "-"),
 336                         (expected & PF_USER ? "U" : "-"),
 337                         (expected & PF_WRITE ? "W" : "-")
 338                         );
 339                 expected = 0;
 340         }
 341 }
 342
 343 /**
 344  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 345  */
 346 tPAddr MM_Allocate(tVAddr VAddr)
 347 {
 348         tPAddr  paddr;
 349         //ENTER("xVAddr", VAddr);
 350         //__asm__ __volatile__ ("xchg %bx,%bx");
 351         // Check if the directory is mapped
 352         if( gaPageDir[ VAddr >> 22 ] == 0 )
 353         {
 354                 // Allocate directory
 355                 paddr = MM_AllocPhys();
 356                 //LOG("paddr = 0x%llx (new table)", paddr);
 357                 if( paddr == 0 ) {
 358                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 359                         //LEAVE('i',0);
 360                         return 0;
 361                 }
 362                 // Map
 363                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 364                 // Mark as user
 365                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 366
 367                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 368                 //LOG("Clearing new table");
 369                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 370         }
 371         // Check if the page is already allocated
 372         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 373                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 374                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 375                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 376         }
 377
 378         // Allocate
 379         paddr = MM_AllocPhys();
 380         //LOG("paddr = 0x%llx", paddr);
 381         if( paddr == 0 ) {
 382                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 383                         VAddr, __builtin_return_address(0));
 384                 //LEAVE('i',0);
 385                 return 0;
 386         }
 387         // Map
 388         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 389         // Mark as user
 390         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 391         // Invalidate Cache for address
 392         INVLPG( VAddr & ~0xFFF );
 393
 394         //LEAVE('X', paddr);
 395         return paddr;
 396 }
 397
 398 /**
 399  * \fn void MM_Deallocate(tVAddr VAddr)
 400  */
 401 void MM_Deallocate(tVAddr VAddr)
 402 {
 403         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 404                 Warning("MM_Deallocate - Directory not mapped");
 405                 return;
 406         }
 407
 408         if(gaPageTable[ VAddr >> 12 ] == 0) {
 409                 Warning("MM_Deallocate - Page is not allocated");
 410                 return;
 411         }
 412
 413         // Dereference page
 414         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 415         // Clear page
 416         gaPageTable[ VAddr >> 12 ] = 0;
 417 }
 418
 419 /**
 420  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 421  * \brief Checks if the passed address is accesable
 422  */
 423 tPAddr MM_GetPhysAddr(tVAddr Addr)
 424 {
 425         if( !(gaPageDir[Addr >> 22] & 1) )
 426                 return 0;
 427         if( !(gaPageTable[Addr >> 12] & 1) )
 428                 return 0;
 429         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 430 }
 431
 432 /**
 433  * \fn void MM_SetCR3(Uint CR3)
 434  * \brief Sets the current process space
 435  */
 436 void MM_SetCR3(Uint CR3)
 437 {
 438         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 439 }
 440
 441 /**
 442  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 443  * \brief Map a physical page to a virtual one
 444  */
 445 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 446 {
 447         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 448         // Sanity check
 449         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 450                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 451                 //LEAVE('i', 0);
 452                 return 0;
 453         }
 454
 455         // Align addresses
 456         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 457
 458         // Check if the directory is mapped
 459         if( gaPageDir[ VAddr >> 22 ] == 0 )
 460         {
 461                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 462
 463                 // Mark as user
 464                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 465
 466                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 467                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 468         }
 469         // Check if the page is already allocated
 470         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 471                 Warning("MM_Map - Allocating to used address");
 472                 //LEAVE('i', 0);
 473                 return 0;
 474         }
 475
 476         // Map
 477         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 478         // Mark as user
 479         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 480
 481         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 482         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 483
 484         // Reference
 485         MM_RefPhys( PAddr );
 486
 487         //LOG("INVLPG( 0x%x )", VAddr);
 488         INVLPG( VAddr );
 489
 490         //LEAVE('i', 1);
 491         return 1;
 492 }
 493
 494 /**
 495  * \fn tVAddr MM_ClearUser()
 496  * \brief Clear user's address space
 497  */
 498 tVAddr MM_ClearUser(void)
 499 {
 500         Uint    i, j;
 501
 502         // Copy Directories
 503         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 504         {
 505                 // Check if directory is not allocated
 506                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 507                         gaPageDir[i] = 0;
 508                         continue;
 509                 }
 510
 511
 512                 for( j = 0; j < 1024; j ++ )
 513                 {
 514                         if( gaPageTable[i*1024+j] & 1 )
 515                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 516                         gaPageTable[i*1024+j] = 0;
 517                 }
 518
 519                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 520                 gaPageDir[i] = 0;
 521                 INVLPG( &gaPageTable[i*1024] );
 522         }
 523         INVLPG( gaPageDir );
 524
 525         return *gpPageCR3;
 526 }
 527
 528 /**
 529  * \fn tPAddr MM_Clone(void)
 530  * \brief Clone the current address space
 531  */
 532 tPAddr MM_Clone(void)
 533 {
 534         Uint    i, j;
 535         tVAddr  ret;
 536         Uint    page = 0;
 537         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 538         void    *tmp;
 539
 540         Mutex_Acquire( &glTempFractal );
 541
 542         // Create Directory Table
 543         *gpTmpCR3 = MM_AllocPhys() | 3;
 544         INVLPG( gaTmpDir );
 545         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 546         memsetd( gaTmpDir, 0, 1024 );
 547
 548         if( Threads_GetPID() != 0 )
 549         {
 550                 // Copy Tables
 551                 for( i = 0; i < 768; i ++)
 552                 {
 553                         // Check if table is allocated
 554                         if( !(gaPageDir[i] & PF_PRESENT) ) {
 555                                 gaTmpDir[i] = 0;
 556                                 page += 1024;
 557                                 continue;
 558                         }
 559
 560                         // Allocate new table
 561                         gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 562                         INVLPG( &gaTmpTable[page] );
 563                         // Fill
 564                         for( j = 0; j < 1024; j ++, page++ )
 565                         {
 566                                 if( !(gaPageTable[page] & PF_PRESENT) ) {
 567                                         gaTmpTable[page] = 0;
 568                                         continue;
 569                                 }
 570
 571                                 // Refrence old page
 572                                 MM_RefPhys( gaPageTable[page] & ~0xFFF );
 573                                 // Add to new table
 574                                 if(gaPageTable[page] & PF_WRITE) {
 575                                         gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 576                                         gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 577                                         INVLPG( page << 12 );
 578                                 }
 579                                 else
 580                                         gaTmpTable[page] = gaPageTable[page];
 581                         }
 582                 }
 583         }
 584
 585         // Map in kernel tables (and make fractal mapping)
 586         for( i = 768; i < 1024; i ++ )
 587         {
 588                 // Fractal
 589                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 590                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 591                         continue;
 592                 }
 593
 594                 if( gaPageDir[i] == 0 ) {
 595                         gaTmpDir[i] = 0;
 596                         continue;
 597                 }
 598
 599                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 600                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 601                 gaTmpDir[i] = gaPageDir[i];
 602         }
 603
 604         // Allocate kernel stack
 605         for(i = KERNEL_STACKS >> 22;
 606                 i < KERNEL_STACKS_END >> 22;
 607                 i ++ )
 608         {
 609                 // Check if directory is allocated
 610                 if( (gaPageDir[i] & 1) == 0 ) {
 611                         gaTmpDir[i] = 0;
 612                         continue;
 613                 }
 614
 615                 // We don't care about other kernel stacks, just the current one
 616                 if( i != kStackBase >> 22 ) {
 617                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 618                         gaTmpDir[i] = 0;
 619                         continue;
 620                 }
 621
 622                 // Create a copy
 623                 gaTmpDir[i] = MM_AllocPhys() | 3;
 624                 INVLPG( &gaTmpTable[i*1024] );
 625                 for( j = 0; j < 1024; j ++ )
 626                 {
 627                         // Is the page allocated? If not, skip
 628                         if( !(gaPageTable[i*1024+j] & 1) ) {
 629                                 gaTmpTable[i*1024+j] = 0;
 630                                 continue;
 631                         }
 632
 633                         // We don't care about other kernel stacks
 634                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 635                                 gaTmpTable[i*1024+j] = 0;
 636                                 continue;
 637                         }
 638
 639                         // Allocate page
 640                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 641
 642                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 643
 644                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 645                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 646                         MM_FreeTemp( (Uint)tmp );
 647                 }
 648         }
 649
 650         ret = *gpTmpCR3 & ~0xFFF;
 651         Mutex_Release( &glTempFractal );
 652
 653         //LEAVE('x', ret);
 654         return ret;
 655 }
 656
 657 /**
 658  * \fn tVAddr MM_NewKStack(void)
 659  * \brief Create a new kernel stack
 660  */
 661 tVAddr MM_NewKStack(void)
 662 {
 663         tVAddr  base;
 664         Uint    i;
 665         for(base = KERNEL_STACKS; base < KERNEL_STACKS_END; base += KERNEL_STACK_SIZE)
 666         {
 667                 // Check if space is free
 668                 if(MM_GetPhysAddr(base) != 0)   continue;
 669                 // Allocate
 670                 //for(i = KERNEL_STACK_SIZE; i -= 0x1000 ; )
 671                 for(i = 0; i < KERNEL_STACK_SIZE; i += 0x1000 )
 672                 {
 673                         if( MM_Allocate(base+i) == 0 )
 674                         {
 675                                 // On error, print a warning and return error
 676                                 Warning("MM_NewKStack - Out of memory");
 677                                 // - Clean up
 678                                 //for( i += 0x1000 ; i < KERNEL_STACK_SIZE; i += 0x1000 )
 679                                 //      MM_Deallocate(base+i);
 680                                 return 0;
 681                         }
 682                 }
 683                 // Success
 684                 Log("MM_NewKStack - Allocated %p", base + KERNEL_STACK_SIZE);
 685                 return base+KERNEL_STACK_SIZE;
 686         }
 687         // No stacks left
 688         Warning("MM_NewKStack - No address space left");
 689         return 0;
 690 }
 691
 692 /**
 693  * \fn tVAddr MM_NewWorkerStack()
 694  * \brief Creates a new worker stack
 695  */
 696 tVAddr MM_NewWorkerStack()
 697 {
 698         Uint    esp, ebp;
 699         Uint    oldstack;
 700         Uint    base, addr;
 701          int    i, j;
 702         Uint    *tmpPage;
 703         tPAddr  pages[WORKER_STACK_SIZE>>12];
 704
 705         // Get the old ESP and EBP
 706         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 707         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 708
 709         // TODO: Thread safety
 710         // Find a free worker stack address
 711         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 712         {
 713                 // Used block
 714                 if( gWorkerStacks[base/32] == -1 ) {
 715                         base += 31;     base &= ~31;
 716                         base --;        // Counteracted by the base++
 717                         continue;
 718                 }
 719                 // Used stack
 720                 if( gWorkerStacks[base/32] & (1 << base) ) {
 721                         continue;
 722                 }
 723                 break;
 724         }
 725         if(base >= NUM_WORKER_STACKS) {
 726                 Warning("Uh-oh! Out of worker stacks");
 727                 return 0;
 728         }
 729
 730         // It's ours now!
 731         gWorkerStacks[base/32] |= (1 << base);
 732         // Make life easier for later calls
 733         giLastUsedWorker = base;
 734         // We have one
 735         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 736         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 737
 738         // Acquire the lock for the temp fractal mappings
 739         Mutex_Acquire(&glTempFractal);
 740
 741         // Set the temp fractals to TID0's address space
 742         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 743         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 744         INVLPG( gaTmpDir );
 745
 746
 747         // Check if the directory is mapped (we are assuming that the stacks
 748         // will fit neatly in a directory)
 749         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 750         if(gaTmpDir[ base >> 22 ] == 0) {
 751                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 752                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 753         }
 754
 755         // Mapping Time!
 756         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 757         //for( addr = WORKER_STACK_SIZE; addr; addr -= 0x1000 )
 758         {
 759                 pages[ addr >> 12 ] = MM_AllocPhys();
 760                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 761         }
 762         *gpTmpCR3 = 0;
 763         // Release the temp mapping lock
 764         Mutex_Release(&glTempFractal);
 765
 766         // Copy the old stack
 767         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 768         esp = oldstack - esp;   // ESP as an offset in the stack
 769
 770         // Make `base` be the top of the stack
 771         base += WORKER_STACK_SIZE;
 772
 773         i = (WORKER_STACK_SIZE>>12) - 1;
 774         // Copy the contents of the old stack to the new one, altering the addresses
 775         // `addr` is refering to bytes from the stack base (mem downwards)
 776         for(addr = 0; addr < esp; addr += 0x1000)
 777         {
 778                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 779                 tmpPage = (void*)MM_MapTemp( pages[i] );
 780                 // Copy old stack
 781                 for(j = 0; j < 1024; j++)
 782                 {
 783                         // Possible Stack address?
 784                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 785                                 tmpPage[j] = base - (oldstack - stack[j]);
 786                         else    // Seems not, best leave it alone
 787                                 tmpPage[j] = stack[j];
 788                 }
 789                 MM_FreeTemp((tVAddr)tmpPage);
 790                 i --;
 791         }
 792
 793         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 794         return base;
 795 }
 796
 797 /**
 798  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 799  * \brief Sets the flags on a page
 800  */
 801 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 802 {
 803         tTabEnt *ent;
 804         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 805         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 806
 807         ent = &gaPageTable[VAddr >> 12];
 808
 809         // Read-Only
 810         if( Mask & MM_PFLAG_RO )
 811         {
 812                 if( Flags & MM_PFLAG_RO ) {
 813                         *ent &= ~PF_WRITE;
 814                 }
 815                 else {
 816                         gaPageDir[VAddr >> 22] |= PF_WRITE;
 817                         *ent |= PF_WRITE;
 818                 }
 819         }
 820
 821         // Kernel
 822         if( Mask & MM_PFLAG_KERNEL )
 823         {
 824                 if( Flags & MM_PFLAG_KERNEL ) {
 825                         *ent &= ~PF_USER;
 826                 }
 827                 else {
 828                         gaPageDir[VAddr >> 22] |= PF_USER;
 829                         *ent |= PF_USER;
 830                 }
 831         }
 832
 833         // Copy-On-Write
 834         if( Mask & MM_PFLAG_COW )
 835         {
 836                 if( Flags & MM_PFLAG_COW ) {
 837                         *ent &= ~PF_WRITE;
 838                         *ent |= PF_COW;
 839                 }
 840                 else {
 841                         *ent &= ~PF_COW;
 842                         *ent |= PF_WRITE;
 843                 }
 844         }
 845
 846         //Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
 847         //      *ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 848 }
 849
 850 /**
 851  * \brief Get the flags on a page
 852  */
 853 Uint MM_GetFlags(tVAddr VAddr)
 854 {
 855         tTabEnt *ent;
 856         Uint    ret = 0;
 857
 858         // Validity Check
 859         if( !(gaPageDir[VAddr >> 22] & 1) )     return 0;
 860         if( !(gaPageTable[VAddr >> 12] & 1) )   return 0;
 861
 862         ent = &gaPageTable[VAddr >> 12];
 863
 864         // Read-Only
 865         if( !(*ent & PF_WRITE) )        ret |= MM_PFLAG_RO;
 866         // Kernel
 867         if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
 868         // Copy-On-Write
 869         if( *ent & PF_COW )     ret |= MM_PFLAG_COW;
 870
 871         return ret;
 872 }
 873
 874 /**
 875  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 876  * \brief Duplicates a virtual page to a physical one
 877  */
 878 tPAddr MM_DuplicatePage(tVAddr VAddr)
 879 {
 880         tPAddr  ret;
 881         Uint    temp;
 882          int    wasRO = 0;
 883
 884         //ENTER("xVAddr", VAddr);
 885
 886         // Check if mapped
 887         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 888         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 889
 890         // Page Align
 891         VAddr &= ~0xFFF;
 892
 893         // Allocate new page
 894         ret = MM_AllocPhys();
 895
 896         // Write-lock the page (to keep data constistent), saving its R/W state
 897         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 898         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 899         INVLPG( VAddr );
 900
 901         // Copy Data
 902         temp = MM_MapTemp(ret);
 903         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 904         MM_FreeTemp(temp);
 905
 906         // Restore Writeable status
 907         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 908         INVLPG(VAddr);
 909
 910         //LEAVE('X', ret);
 911         return ret;
 912 }
 913
 914 /**
 915  * \fn Uint MM_MapTemp(tPAddr PAddr)
 916  * \brief Create a temporary memory mapping
 917  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 918  */
 919 tVAddr MM_MapTemp(tPAddr PAddr)
 920 {
 921          int    i;
 922
 923         //ENTER("XPAddr", PAddr);
 924
 925         PAddr &= ~0xFFF;
 926
 927         //LOG("glTempMappings = %i", glTempMappings);
 928
 929         for(;;)
 930         {
 931                 Mutex_Acquire( &glTempMappings );
 932
 933                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 934                 {
 935                         // Check if page used
 936                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 937                         // Mark as used
 938                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 939                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 940                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 941                         Mutex_Release( &glTempMappings );
 942                         return TEMP_MAP_ADDR + (i << 12);
 943                 }
 944                 Mutex_Release( &glTempMappings );
 945                 Threads_Yield();        // TODO: Use a sleep queue here instead
 946         }
 947 }
 948
 949 /**
 950  * \fn void MM_FreeTemp(tVAddr PAddr)
 951  * \brief Free's a temp mapping
 952  */
 953 void MM_FreeTemp(tVAddr VAddr)
 954 {
 955          int    i = VAddr >> 12;
 956         //ENTER("xVAddr", VAddr);
 957
 958         if(i >= (TEMP_MAP_ADDR >> 12))
 959                 gaPageTable[ i ] = 0;
 960
 961         //LEAVE('-');
 962 }
 963
 964 /**
 965  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 966  * \brief Allocates a contigous number of pages
 967  */
 968 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 969 {
 970          int    i, j;
 971
 972         PAddr &= ~0xFFF;
 973
 974         // Scan List
 975         for( i = 0; i < NUM_HW_PAGES; i ++ )
 976         {
 977                 // Check if addr used
 978                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 979                         continue;
 980
 981                 // Check possible region
 982                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 983                 {
 984                         // If there is an allocated page in the region we are testing, break
 985                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 986                 }
 987                 // Is it all free?
 988                 if( j == Number )
 989                 {
 990                         // Allocate
 991                         for( j = 0; j < Number; j++ ) {
 992                                 MM_RefPhys( PAddr + (j<<12) );
 993                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 994                         }
 995                         return HW_MAP_ADDR + (i<<12);
 996                 }
 997         }
 998         // If we don't find any, return NULL
 999         return 0;
1000 }
1001
1002 /**
1003  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
1004  * \brief Allocates DMA physical memory
1005  * \param Pages Number of pages required
1006  * \param MaxBits       Maximum number of bits the physical address can have
1007  * \param PhysAddr      Pointer to the location to place the physical address allocated
1008  * \return Virtual address allocate
1009  */
1010 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
1011 {
1012         tPAddr  maxCheck = (1 << MaxBits);
1013         tPAddr  phys;
1014         tVAddr  ret;
1015
1016         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
1017
1018         // Sanity Check
1019         if(MaxBits < 12 || !PhysAddr) {
1020                 LEAVE('i', 0);
1021                 return 0;
1022         }
1023
1024         // Bound
1025         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
1026
1027         // Fast Allocate
1028         if(Pages == 1 && MaxBits >= PHYS_BITS)
1029         {
1030                 phys = MM_AllocPhys();
1031                 *PhysAddr = phys;
1032                 ret = MM_MapHWPages(phys, 1);
1033                 if(ret == 0) {
1034                         MM_DerefPhys(phys);
1035                         LEAVE('i', 0);
1036                         return 0;
1037                 }
1038                 LEAVE('x', ret);
1039                 return ret;
1040         }
1041
1042         // Slow Allocate
1043         phys = MM_AllocPhysRange(Pages, MaxBits);
1044         // - Was it allocated?
1045         if(phys == 0) {
1046                 LEAVE('i', 0);
1047                 return 0;
1048         }
1049
1050         // Allocated successfully, now map
1051         ret = MM_MapHWPages(phys, Pages);
1052         if( ret == 0 ) {
1053                 // If it didn't map, free then return 0
1054                 for(;Pages--;phys+=0x1000)
1055                         MM_DerefPhys(phys);
1056                 LEAVE('i', 0);
1057                 return 0;
1058         }
1059
1060         *PhysAddr = phys;
1061         LEAVE('x', ret);
1062         return ret;
1063 }
1064
1065 /**
1066  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1067  * \brief Unmap a hardware page
1068  */
1069 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1070 {
1071          int    i, j;
1072
1073         //Log_Debug("VirtMem", "MM_UnmapHWPages: (VAddr=0x%08x, Number=%i)", VAddr, Number);
1074
1075         // Sanity Check
1076         if(VAddr < HW_MAP_ADDR || VAddr+Number*0x1000 > HW_MAP_MAX)     return;
1077
1078         i = VAddr >> 12;
1079
1080         Mutex_Acquire( &glTempMappings );       // Temp and HW share a directory, so they share a lock
1081
1082         for( j = 0; j < Number; j++ )
1083         {
1084                 MM_DerefPhys( gaPageTable[ i + j ] & ~0xFFF );
1085                 gaPageTable[ i + j ] = 0;
1086         }
1087
1088         Mutex_Release( &glTempMappings );
1089 }
1090
1091 // --- EXPORTS ---
1092 EXPORT(MM_GetPhysAddr);
1093 EXPORT(MM_Map);
1094 //EXPORT(MM_Unmap);
1095 EXPORT(MM_MapHWPages);
1096 EXPORT(MM_AllocDMA);
1097 EXPORT(MM_UnmapHWPages);