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