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