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_phys.h>
  16 #include <proc.h>
  17
  18 #if USE_PAE
  19 # define TAB    21
  20 # define DIR    30
  21 #else
  22 # define TAB    22
  23 #endif
  24
  25 #define KERNEL_STACKS           0xF0000000
  26 #define KERNEL_STACK_SIZE       0x00008000
  27 #define KERNEL_STACKS_END       0xFC000000
  28 #define WORKER_STACKS           0x00100000      // Thread0 Only!
  29 #define WORKER_STACK_SIZE       KERNEL_STACK_SIZE
  30 #define WORKER_STACKS_END       0xB0000000
  31 #define NUM_WORKER_STACKS       ((WORKER_STACKS_END-WORKER_STACKS)/WORKER_STACK_SIZE)
  32
  33 #define PAE_PAGE_TABLE_ADDR     0xFC000000      // 16 MiB
  34 #define PAE_PAGE_DIR_ADDR       0xFCFC0000      // 16 KiB
  35 #define PAE_PAGE_PDPT_ADDR      0xFCFC3F00      // 32 bytes
  36 #define PAE_TMP_PDPT_ADDR       0xFCFC3F20      // 32 bytes
  37 #define PAE_TMP_DIR_ADDR        0xFCFE0000      // 16 KiB
  38 #define PAE_TMP_TABLE_ADDR      0xFD000000      // 16 MiB
  39
  40 #define PAGE_TABLE_ADDR 0xFC000000
  41 #define PAGE_DIR_ADDR   0xFC3F0000
  42 #define PAGE_CR3_ADDR   0xFC3F0FC0
  43 #define TMP_CR3_ADDR    0xFC3F0FC4      // Part of core instead of temp
  44 #define TMP_DIR_ADDR    0xFC3F1000      // Same
  45 #define TMP_TABLE_ADDR  0xFC400000
  46
  47 #define HW_MAP_ADDR             0xFE000000
  48 #define HW_MAP_MAX              0xFFEF0000
  49 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  50 #define TEMP_MAP_ADDR   0xFFEF0000      // Allows 16 "temp" pages
  51 #define NUM_TEMP_PAGES  16
  52 #define LAST_BLOCK_ADDR 0xFFFF0000      // Free space for kernel provided user code/ *(-1) protection
  53
  54 #define PF_PRESENT      0x1
  55 #define PF_WRITE        0x2
  56 #define PF_USER         0x4
  57 #define PF_COW          0x200
  58 #define PF_PAGED        0x400
  59
  60 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  61
  62 #if USE_PAE
  63 typedef Uint64  tTabEnt;
  64 #else
  65 typedef Uint32  tTabEnt;
  66 #endif
  67
  68 // === IMPORTS ===
  69 extern Uint32   gaInitPageDir[1024];
  70 extern Uint32   gaInitPageTable[1024];
  71 extern void     Threads_SegFault(tVAddr Addr);
  72 extern void     Error_Backtrace(Uint eip, Uint ebp);
  73
  74 // === PROTOTYPES ===
  75 void    MM_PreinitVirtual();
  76 void    MM_InstallVirtual();
  77 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  78 void    MM_DumpTables(tVAddr Start, tVAddr End);
  79 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  80
  81 // === GLOBALS ===
  82 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  83 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  84 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  85 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  86 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  87 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  88
  89 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  90 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  91 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  92 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  93 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  94 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  95  int    gbUsePAE = 0;
  96  int    gilTempMappings = 0;
  97  int    gilTempFractal = 0;
  98 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
  99  int    giLastUsedWorker = 0;
 100
 101 // === CODE ===
 102 /**
 103  * \fn void MM_PreinitVirtual()
 104  * \brief Maps the fractal mappings
 105  */
 106 void MM_PreinitVirtual()
 107 {
 108         #if USE_PAE
 109         gaInitPageDir[ ((PAGE_TABLE_ADDR >> TAB)-3*512+3)*2 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 110         #else
 111         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 112         #endif
 113         INVLPG( PAGE_TABLE_ADDR );
 114 }
 115
 116 /**
 117  * \fn void MM_InstallVirtual()
 118  * \brief Sets up the constant page mappings
 119  */
 120 void MM_InstallVirtual()
 121 {
 122          int    i;
 123
 124         #if USE_PAE
 125         // --- Pre-Allocate kernel tables
 126         for( i = KERNEL_BASE >> TAB; i < 1024*4; i ++ )
 127         {
 128                 if( gaPAE_PageDir[ i ] )        continue;
 129
 130                 // Skip stack tables, they are process unique
 131                 if( i > KERNEL_STACKS >> TAB && i < KERNEL_STACKS_END >> TAB) {
 132                         gaPAE_PageDir[ i ] = 0;
 133                         continue;
 134                 }
 135                 // Preallocate table
 136                 gaPAE_PageDir[ i ] = MM_AllocPhys() | 3;
 137                 INVLPG( &gaPAE_PageTable[i*512] );
 138                 memset( &gaPAE_PageTable[i*512], 0, 0x1000 );
 139         }
 140         #else
 141         // --- Pre-Allocate kernel tables
 142         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 143         {
 144                 if( gaPageDir[ i ] )    continue;
 145                 // Skip stack tables, they are process unique
 146                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 147                         gaPageDir[ i ] = 0;
 148                         continue;
 149                 }
 150                 // Preallocate table
 151                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 152                 INVLPG( &gaPageTable[i*1024] );
 153                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 154         }
 155         #endif
 156 }
 157
 158 /**
 159  * \brief Cleans up the SMP required mappings
 160  */
 161 void MM_FinishVirtualInit()
 162 {
 163         #if USE_PAE
 164         gaInitPDPT[ 0 ] = 0;
 165         #else
 166         gaInitPageDir[ 0 ] = 0;
 167         #endif
 168 }
 169
 170 /**
 171  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 172  * \brief Called on a page fault
 173  */
 174 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 175 {
 176         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 177
 178         // -- Check for COW --
 179         if( gaPageDir  [Addr>>22] & PF_PRESENT
 180          && gaPageTable[Addr>>12] & PF_PRESENT
 181          && gaPageTable[Addr>>12] & PF_COW )
 182         {
 183                 tPAddr  paddr;
 184                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 185                 {
 186                         gaPageTable[Addr>>12] &= ~PF_COW;
 187                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 188                 }
 189                 else
 190                 {
 191                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 192                         paddr = MM_DuplicatePage( Addr );
 193                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 194                         gaPageTable[Addr>>12] &= PF_USER;
 195                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 196                 }
 197
 198                 INVLPG( Addr & ~0xFFF );
 199                 //LEAVE('-')
 200                 return;
 201         }
 202
 203         // If it was a user, tell the thread handler
 204         if(ErrorCode & 4) {
 205                 Warning("%s %s %s memory%s",
 206                         (ErrorCode&4?"User":"Kernel"),
 207                         (ErrorCode&2?"write to":"read from"),
 208                         (ErrorCode&1?"bad/locked":"non-present"),
 209                         (ErrorCode&16?" (Instruction Fetch)":"")
 210                         );
 211                 Warning("User Pagefault: Instruction at %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 212                 __asm__ __volatile__ ("sti");   // Restart IRQs
 213                 Threads_SegFault(Addr);
 214                 return ;
 215         }
 216
 217         Debug_KernelPanic();
 218
 219         // -- Check Error Code --
 220         if(ErrorCode & 8)
 221                 Warning("Reserved Bits Trashed!");
 222         else
 223         {
 224                 Warning("%s %s %s memory%s",
 225                         (ErrorCode&4?"User":"Kernel"),
 226                         (ErrorCode&2?"write to":"read from"),
 227                         (ErrorCode&1?"bad/locked":"non-present"),
 228                         (ErrorCode&16?" (Instruction Fetch)":"")
 229                         );
 230         }
 231
 232         Log("Code at %p accessed %p", Regs->eip, Addr);
 233         // Print Stack Backtrace
 234         Error_Backtrace(Regs->eip, Regs->ebp);
 235
 236         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 237         if( gaPageDir[Addr>>22] & PF_PRESENT )
 238                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 239
 240         //MM_DumpTables(0, -1);
 241
 242         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 243 }
 244
 245 /**
 246  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 247  * \brief Dumps the layout of the page tables
 248  */
 249 void MM_DumpTables(tVAddr Start, tVAddr End)
 250 {
 251         tVAddr  rangeStart = 0;
 252         tPAddr  expected = 0;
 253         tVAddr  curPos;
 254         Uint    page;
 255         const tPAddr    MASK = ~0xF98;
 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                 {
 284                         if(expected) {
 285                                 Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 286                                         rangeStart, curPos - 1,
 287                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 288                                         (expected & ~0xFFF) - 1,
 289                                         (expected & PF_PAGED ? "p" : "-"),
 290                                         (expected & PF_COW ? "C" : "-"),
 291                                         (expected & PF_USER ? "U" : "-"),
 292                                         (expected & PF_WRITE ? "W" : "-")
 293                                         );
 294                                 expected = 0;
 295                         }
 296                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 297                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 298
 299                         expected = (gaPageTable[page] & MASK);
 300                         rangeStart = curPos;
 301                 }
 302                 if(expected)    expected += 0x1000;
 303         }
 304
 305         if(expected) {
 306                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 307                         rangeStart, curPos - 1,
 308                         gaPageTable[rangeStart>>12] & ~0xFFF,
 309                         (expected & ~0xFFF) - 1,
 310                         (expected & PF_PAGED ? "p" : "-"),
 311                         (expected & PF_COW ? "C" : "-"),
 312                         (expected & PF_USER ? "U" : "-"),
 313                         (expected & PF_WRITE ? "W" : "-")
 314                         );
 315                 expected = 0;
 316         }
 317 }
 318
 319 /**
 320  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 321  */
 322 tPAddr MM_Allocate(tVAddr VAddr)
 323 {
 324         tPAddr  paddr;
 325         //ENTER("xVAddr", VAddr);
 326         //__asm__ __volatile__ ("xchg %bx,%bx");
 327         // Check if the directory is mapped
 328         if( gaPageDir[ VAddr >> 22 ] == 0 )
 329         {
 330                 // Allocate directory
 331                 paddr = MM_AllocPhys();
 332                 //LOG("paddr = 0x%llx (new table)", paddr);
 333                 if( paddr == 0 ) {
 334                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 335                         //LEAVE('i',0);
 336                         return 0;
 337                 }
 338                 // Map
 339                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 340                 // Mark as user
 341                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 342
 343                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 344                 //LOG("Clearing new table");
 345                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 346         }
 347         // Check if the page is already allocated
 348         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 349                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 350                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 351                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 352         }
 353
 354         // Allocate
 355         paddr = MM_AllocPhys();
 356         //LOG("paddr = 0x%llx", paddr);
 357         if( paddr == 0 ) {
 358                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 359                         VAddr, __builtin_return_address(0));
 360                 //LEAVE('i',0);
 361                 return 0;
 362         }
 363         // Map
 364         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 365         // Mark as user
 366         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 367         // Invalidate Cache for address
 368         INVLPG( VAddr & ~0xFFF );
 369
 370         //LEAVE('X', paddr);
 371         return paddr;
 372 }
 373
 374 /**
 375  * \fn void MM_Deallocate(tVAddr VAddr)
 376  */
 377 void MM_Deallocate(tVAddr VAddr)
 378 {
 379         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 380                 Warning("MM_Deallocate - Directory not mapped");
 381                 return;
 382         }
 383
 384         if(gaPageTable[ VAddr >> 12 ] == 0) {
 385                 Warning("MM_Deallocate - Page is not allocated");
 386                 return;
 387         }
 388
 389         // Dereference page
 390         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 391         // Clear page
 392         gaPageTable[ VAddr >> 12 ] = 0;
 393 }
 394
 395 /**
 396  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 397  * \brief Checks if the passed address is accesable
 398  */
 399 tPAddr MM_GetPhysAddr(tVAddr Addr)
 400 {
 401         if( !(gaPageDir[Addr >> 22] & 1) )
 402                 return 0;
 403         if( !(gaPageTable[Addr >> 12] & 1) )
 404                 return 0;
 405         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 406 }
 407
 408
 409 /**
 410  * \fn int MM_IsUser(tVAddr VAddr)
 411  * \brief Checks if a page is user accessable
 412  */
 413 int MM_IsUser(tVAddr VAddr)
 414 {
 415         if( !(gaPageDir[VAddr >> 22] & 1) )
 416                 return 0;
 417         if( !(gaPageTable[VAddr >> 12] & 1) )
 418                 return 0;
 419         if( !(gaPageTable[VAddr >> 12] & PF_USER) )
 420                 return 0;
 421         return 1;
 422 }
 423
 424 /**
 425  * \fn void MM_SetCR3(tPAddr CR3)
 426  * \brief Sets the current process space
 427  */
 428 void MM_SetCR3(tPAddr CR3)
 429 {
 430         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 431 }
 432
 433 /**
 434  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 435  * \brief Map a physical page to a virtual one
 436  */
 437 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 438 {
 439         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 440         // Sanity check
 441         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 442                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 443                 //LEAVE('i', 0);
 444                 return 0;
 445         }
 446
 447         // Align addresses
 448         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 449
 450         // Check if the directory is mapped
 451         if( gaPageDir[ VAddr >> 22 ] == 0 )
 452         {
 453                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 454
 455                 // Mark as user
 456                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 457
 458                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 459                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 460         }
 461         // Check if the page is already allocated
 462         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 463                 Warning("MM_Map - Allocating to used address");
 464                 //LEAVE('i', 0);
 465                 return 0;
 466         }
 467
 468         // Map
 469         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 470         // Mark as user
 471         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 472
 473         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 474         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 475
 476         // Reference
 477         MM_RefPhys( PAddr );
 478
 479         //LOG("INVLPG( 0x%x )", VAddr);
 480         INVLPG( VAddr );
 481
 482         //LEAVE('i', 1);
 483         return 1;
 484 }
 485
 486 /**
 487  * \fn tVAddr MM_ClearUser()
 488  * \brief Clear user's address space
 489  */
 490 tVAddr MM_ClearUser()
 491 {
 492         Uint    i, j;
 493
 494         // Copy Directories
 495         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 496         {
 497                 // Check if directory is not allocated
 498                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 499                         gaPageDir[i] = 0;
 500                         continue;
 501                 }
 502
 503
 504                 for( j = 0; j < 1024; j ++ )
 505                 {
 506                         if( gaPageTable[i*1024+j] & 1 )
 507                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 508                         gaPageTable[i*1024+j] = 0;
 509                 }
 510
 511                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 512                 gaPageDir[i] = 0;
 513                 INVLPG( &gaPageTable[i*1024] );
 514         }
 515         INVLPG( gaPageDir );
 516
 517         return *gpPageCR3;
 518 }
 519
 520 /**
 521  * \fn tPAddr MM_Clone()
 522  * \brief Clone the current address space
 523  */
 524 tPAddr MM_Clone()
 525 {
 526         Uint    i, j;
 527         tVAddr  ret;
 528         Uint    page = 0;
 529         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 530         void    *tmp;
 531
 532         LOCK( &gilTempFractal );
 533
 534         // Create Directory Table
 535         *gpTmpCR3 = MM_AllocPhys() | 3;
 536         INVLPG( gaTmpDir );
 537         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 538         memsetd( gaTmpDir, 0, 1024 );
 539
 540         // Copy Tables
 541         for( i = 0; i < 768; i ++)
 542         {
 543                 // Check if table is allocated
 544                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 545                         gaTmpDir[i] = 0;
 546                         page += 1024;
 547                         continue;
 548                 }
 549
 550                 // Allocate new table
 551                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 552                 INVLPG( &gaTmpTable[page] );
 553                 // Fill
 554                 for( j = 0; j < 1024; j ++, page++ )
 555                 {
 556                         if( !(gaPageTable[page] & PF_PRESENT) ) {
 557                                 gaTmpTable[page] = 0;
 558                                 continue;
 559                         }
 560
 561                         // Refrence old page
 562                         MM_RefPhys( gaPageTable[page] & ~0xFFF );
 563                         // Add to new table
 564                         if(gaPageTable[page] & PF_WRITE) {
 565                                 gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 566                                 gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 567                                 INVLPG( page << 12 );
 568                         }
 569                         else
 570                                 gaTmpTable[page] = gaPageTable[page];
 571                 }
 572         }
 573
 574         // Map in kernel tables (and make fractal mapping)
 575         for( i = 768; i < 1024; i ++ )
 576         {
 577                 // Fractal
 578                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 579                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 580                         continue;
 581                 }
 582
 583                 if( gaPageDir[i] == 0 ) {
 584                         gaTmpDir[i] = 0;
 585                         continue;
 586                 }
 587
 588                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 589                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 590                 gaTmpDir[i] = gaPageDir[i];
 591         }
 592
 593         // Allocate kernel stack
 594         for(i = KERNEL_STACKS >> 22;
 595                 i < KERNEL_STACKS_END >> 22;
 596                 i ++ )
 597         {
 598                 // Check if directory is allocated
 599                 if( (gaPageDir[i] & 1) == 0 ) {
 600                         gaTmpDir[i] = 0;
 601                         continue;
 602                 }
 603
 604                 // We don't care about other kernel stacks, just the current one
 605                 if( i != kStackBase >> 22 ) {
 606                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 607                         gaTmpDir[i] = 0;
 608                         continue;
 609                 }
 610
 611                 // Create a copy
 612                 gaTmpDir[i] = MM_AllocPhys() | 3;
 613                 INVLPG( &gaTmpTable[i*1024] );
 614                 for( j = 0; j < 1024; j ++ )
 615                 {
 616                         // Is the page allocated? If not, skip
 617                         if( !(gaPageTable[i*1024+j] & 1) ) {
 618                                 gaTmpTable[i*1024+j] = 0;
 619                                 continue;
 620                         }
 621
 622                         // We don't care about other kernel stacks
 623                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 624                                 gaTmpTable[i*1024+j] = 0;
 625                                 continue;
 626                         }
 627
 628                         // Allocate page
 629                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 630
 631                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 632
 633                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 634                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 635                         MM_FreeTemp( (Uint)tmp );
 636                 }
 637         }
 638
 639         ret = *gpTmpCR3 & ~0xFFF;
 640         RELEASE( &gilTempFractal );
 641
 642         //LEAVE('x', ret);
 643         return ret;
 644 }
 645
 646 /**
 647  * \fn tVAddr MM_NewKStack()
 648  * \brief Create a new kernel stack
 649  */
 650 tVAddr MM_NewKStack()
 651 {
 652         tVAddr  base = KERNEL_STACKS;
 653         Uint    i;
 654         for(;base<KERNEL_STACKS_END;base+=KERNEL_STACK_SIZE)
 655         {
 656                 if(MM_GetPhysAddr(base) != 0)   continue;
 657                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 658                         MM_Allocate(base+i);
 659                 }
 660                 return base+KERNEL_STACK_SIZE;
 661         }
 662         Warning("MM_NewKStack - No address space left\n");
 663         return 0;
 664 }
 665
 666 /**
 667  * \fn tVAddr MM_NewWorkerStack()
 668  * \brief Creates a new worker stack
 669  */
 670 tVAddr MM_NewWorkerStack()
 671 {
 672         Uint    esp, ebp;
 673         Uint    oldstack;
 674         Uint    base, addr;
 675          int    i, j;
 676         Uint    *tmpPage;
 677         tPAddr  pages[WORKER_STACK_SIZE>>12];
 678
 679         // Get the old ESP and EBP
 680         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 681         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 682
 683         // Find a free worker stack address
 684         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 685         {
 686                 // Used block
 687                 if( gWorkerStacks[base/32] == -1 ) {
 688                         base += 31;     base &= ~31;
 689                         base --;        // Counteracted by the base++
 690                         continue;
 691                 }
 692                 // Used stack
 693                 if( gWorkerStacks[base/32] & (1 << base) ) {
 694                         continue;
 695                 }
 696                 break;
 697         }
 698         if(base >= NUM_WORKER_STACKS) {
 699                 Warning("Uh-oh! Out of worker stacks");
 700                 return 0;
 701         }
 702
 703         // It's ours now!
 704         gWorkerStacks[base/32] |= (1 << base);
 705         // Make life easier for later calls
 706         giLastUsedWorker = base;
 707         // We have one
 708         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 709         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 710
 711         // Acquire the lock for the temp fractal mappings
 712         LOCK(&gilTempFractal);
 713
 714         // Set the temp fractals to TID0's address space
 715         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 716         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 717         INVLPG( gaTmpDir );
 718
 719
 720         // Check if the directory is mapped (we are assuming that the stacks
 721         // will fit neatly in a directory)
 722         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 723         if(gaTmpDir[ base >> 22 ] == 0) {
 724                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 725                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 726         }
 727
 728         // Mapping Time!
 729         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 730         {
 731                 pages[ addr >> 12 ] = MM_AllocPhys();
 732                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 733         }
 734         *gpTmpCR3 = 0;
 735         // Release the temp mapping lock
 736         RELEASE(&gilTempFractal);
 737
 738         // Copy the old stack
 739         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 740         esp = oldstack - esp;   // ESP as an offset in the stack
 741
 742         // Make `base` be the top of the stack
 743         base += WORKER_STACK_SIZE;
 744
 745         i = (WORKER_STACK_SIZE>>12) - 1;
 746         // Copy the contents of the old stack to the new one, altering the addresses
 747         // `addr` is refering to bytes from the stack base (mem downwards)
 748         for(addr = 0; addr < esp; addr += 0x1000)
 749         {
 750                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 751                 tmpPage = (void*)MM_MapTemp( pages[i] );
 752                 // Copy old stack
 753                 for(j = 0; j < 1024; j++)
 754                 {
 755                         // Possible Stack address?
 756                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 757                                 tmpPage[j] = base - (oldstack - stack[j]);
 758                         else    // Seems not, best leave it alone
 759                                 tmpPage[j] = stack[j];
 760                 }
 761                 MM_FreeTemp((tVAddr)tmpPage);
 762                 i --;
 763         }
 764
 765         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 766         return base;
 767 }
 768
 769 /**
 770  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 771  * \brief Sets the flags on a page
 772  */
 773 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 774 {
 775         tTabEnt *ent;
 776         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 777         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 778
 779         ent = &gaPageTable[VAddr >> 12];
 780
 781         // Read-Only
 782         if( Mask & MM_PFLAG_RO )
 783         {
 784                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 785                 else    *ent |= PF_WRITE;
 786         }
 787
 788         // Kernel
 789         if( Mask & MM_PFLAG_KERNEL )
 790         {
 791                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 792                 else    *ent |= PF_USER;
 793         }
 794
 795         // Copy-On-Write
 796         if( Mask & MM_PFLAG_COW )
 797         {
 798                 if( Flags & MM_PFLAG_COW ) {
 799                         *ent &= ~PF_WRITE;
 800                         *ent |= PF_COW;
 801                 }
 802                 else {
 803                         *ent &= ~PF_COW;
 804                         *ent |= PF_WRITE;
 805                 }
 806         }
 807 }
 808
 809 /**
 810  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 811  * \brief Duplicates a virtual page to a physical one
 812  */
 813 tPAddr MM_DuplicatePage(tVAddr VAddr)
 814 {
 815         tPAddr  ret;
 816         Uint    temp;
 817          int    wasRO = 0;
 818
 819         //ENTER("xVAddr", VAddr);
 820
 821         // Check if mapped
 822         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 823         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 824
 825         // Page Align
 826         VAddr &= ~0xFFF;
 827
 828         // Allocate new page
 829         ret = MM_AllocPhys();
 830
 831         // Write-lock the page (to keep data constistent), saving its R/W state
 832         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 833         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 834         INVLPG( VAddr );
 835
 836         // Copy Data
 837         temp = MM_MapTemp(ret);
 838         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 839         MM_FreeTemp(temp);
 840
 841         // Restore Writeable status
 842         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 843         INVLPG(VAddr);
 844
 845         //LEAVE('X', ret);
 846         return ret;
 847 }
 848
 849 /**
 850  * \fn Uint MM_MapTemp(tPAddr PAddr)
 851  * \brief Create a temporary memory mapping
 852  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 853  */
 854 tVAddr MM_MapTemp(tPAddr PAddr)
 855 {
 856          int    i;
 857
 858         //ENTER("XPAddr", PAddr);
 859
 860         PAddr &= ~0xFFF;
 861
 862         //LOG("gilTempMappings = %i", gilTempMappings);
 863
 864         for(;;)
 865         {
 866                 LOCK( &gilTempMappings );
 867
 868                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 869                 {
 870                         // Check if page used
 871                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 872                         // Mark as used
 873                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 874                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 875                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 876                         RELEASE( &gilTempMappings );
 877                         return TEMP_MAP_ADDR + (i << 12);
 878                 }
 879                 RELEASE( &gilTempMappings );
 880                 Threads_Yield();
 881         }
 882 }
 883
 884 /**
 885  * \fn void MM_FreeTemp(tVAddr PAddr)
 886  * \brief Free's a temp mapping
 887  */
 888 void MM_FreeTemp(tVAddr VAddr)
 889 {
 890          int    i = VAddr >> 12;
 891         //ENTER("xVAddr", VAddr);
 892
 893         if(i >= (TEMP_MAP_ADDR >> 12))
 894                 gaPageTable[ i ] = 0;
 895
 896         //LEAVE('-');
 897 }
 898
 899 /**
 900  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 901  * \brief Allocates a contigous number of pages
 902  */
 903 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 904 {
 905          int    i, j;
 906
 907         PAddr &= ~0xFFF;
 908
 909         // Scan List
 910         for( i = 0; i < NUM_HW_PAGES; i ++ )
 911         {
 912                 // Check if addr used
 913                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 914                         continue;
 915
 916                 // Check possible region
 917                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 918                 {
 919                         // If there is an allocated page in the region we are testing, break
 920                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 921                 }
 922                 // Is it all free?
 923                 if( j == Number )
 924                 {
 925                         // Allocate
 926                         for( j = 0; j < Number; j++ ) {
 927                                 MM_RefPhys( PAddr + (j<<12) );
 928                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 929                         }
 930                         return HW_MAP_ADDR + (i<<12);
 931                 }
 932         }
 933         // If we don't find any, return NULL
 934         return 0;
 935 }
 936
 937 /**
 938  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 939  * \brief Allocates DMA physical memory
 940  * \param Pages Number of pages required
 941  * \param MaxBits       Maximum number of bits the physical address can have
 942  * \param PhysAddr      Pointer to the location to place the physical address allocated
 943  * \return Virtual address allocate
 944  */
 945 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 946 {
 947         tPAddr  maxCheck = (1 << MaxBits);
 948         tPAddr  phys;
 949         tVAddr  ret;
 950
 951         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
 952
 953         // Sanity Check
 954         if(MaxBits < 12 || !PhysAddr) {
 955                 LEAVE('i', 0);
 956                 return 0;
 957         }
 958
 959         // Bound
 960         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
 961
 962         // Fast Allocate
 963         if(Pages == 1 && MaxBits >= PHYS_BITS)
 964         {
 965                 phys = MM_AllocPhys();
 966                 *PhysAddr = phys;
 967                 ret = MM_MapHWPages(phys, 1);
 968                 if(ret == 0) {
 969                         MM_DerefPhys(phys);
 970                         LEAVE('i', 0);
 971                         return 0;
 972                 }
 973                 LEAVE('x', ret);
 974                 return ret;
 975         }
 976
 977         // Slow Allocate
 978         phys = MM_AllocPhysRange(Pages, MaxBits);
 979         // - Was it allocated?
 980         if(phys == 0) {
 981                 LEAVE('i', 0);
 982                 return 0;
 983         }
 984
 985         // Allocated successfully, now map
 986         ret = MM_MapHWPages(phys, Pages);
 987         if( ret == 0 ) {
 988                 // If it didn't map, free then return 0
 989                 for(;Pages--;phys+=0x1000)
 990                         MM_DerefPhys(phys);
 991                 LEAVE('i', 0);
 992                 return 0;
 993         }
 994
 995         *PhysAddr = phys;
 996         LEAVE('x', ret);
 997         return ret;
 998 }
 999
1000 /**
1001  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1002  * \brief Unmap a hardware page
1003  */
1004 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1005 {
1006          int    i, j;
1007         // Sanity Check
1008         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
1009
1010         i = VAddr >> 12;
1011
1012         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
1013
1014         for( j = 0; j < Number; j++ )
1015         {
1016                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
1017                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
1018         }
1019
1020         RELEASE( &gilTempMappings );
1021 }
1022
1023 // --- EXPORTS ---
1024 EXPORT(MM_GetPhysAddr);
1025 EXPORT(MM_Map);
1026 //EXPORT(MM_Unmap);
1027 EXPORT(MM_MapHWPages);
1028 EXPORT(MM_AllocDMA);
1029 EXPORT(MM_UnmapHWPages);