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 void     _UsertextEnd, _UsertextBase;
  70 extern Uint32   gaInitPageDir[1024];
  71 extern Uint32   gaInitPageTable[1024];
  72 extern void     Threads_SegFault(tVAddr Addr);
  73 extern void     Error_Backtrace(Uint eip, Uint ebp);
  74
  75 // === PROTOTYPES ===
  76 void    MM_PreinitVirtual();
  77 void    MM_InstallVirtual();
  78 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  79 void    MM_DumpTables(tVAddr Start, tVAddr End);
  80 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  81
  82 // === GLOBALS ===
  83 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  84 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  85 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  86 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  87 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  88 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  89
  90 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  91 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  92 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  93 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  94 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  95 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  96  int    gbUsePAE = 0;
  97  int    gilTempMappings = 0;
  98  int    gilTempFractal = 0;
  99 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
 100  int    giLastUsedWorker = 0;
 101
 102 // === CODE ===
 103 /**
 104  * \fn void MM_PreinitVirtual()
 105  * \brief Maps the fractal mappings
 106  */
 107 void MM_PreinitVirtual()
 108 {
 109         #if USE_PAE
 110         gaInitPageDir[ ((PAGE_TABLE_ADDR >> TAB)-3*512+3)*2 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 111         #else
 112         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 113         #endif
 114         INVLPG( PAGE_TABLE_ADDR );
 115 }
 116
 117 /**
 118  * \fn void MM_InstallVirtual()
 119  * \brief Sets up the constant page mappings
 120  */
 121 void MM_InstallVirtual()
 122 {
 123          int    i;
 124
 125         #if USE_PAE
 126         // --- Pre-Allocate kernel tables
 127         for( i = KERNEL_BASE >> TAB; i < 1024*4; i ++ )
 128         {
 129                 if( gaPAE_PageDir[ i ] )        continue;
 130
 131                 // Skip stack tables, they are process unique
 132                 if( i > KERNEL_STACKS >> TAB && i < KERNEL_STACKS_END >> TAB) {
 133                         gaPAE_PageDir[ i ] = 0;
 134                         continue;
 135                 }
 136                 // Preallocate table
 137                 gaPAE_PageDir[ i ] = MM_AllocPhys() | 3;
 138                 INVLPG( &gaPAE_PageTable[i*512] );
 139                 memset( &gaPAE_PageTable[i*512], 0, 0x1000 );
 140         }
 141         #else
 142         // --- Pre-Allocate kernel tables
 143         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 144         {
 145                 if( gaPageDir[ i ] )    continue;
 146                 // Skip stack tables, they are process unique
 147                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 148                         gaPageDir[ i ] = 0;
 149                         continue;
 150                 }
 151                 // Preallocate table
 152                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 153                 INVLPG( &gaPageTable[i*1024] );
 154                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 155         }
 156         #endif
 157
 158         // Unset kernel on the User Text pages
 159         for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
 160                 Log("MM_SetFlags( 0x%08x, 0, MM_PFLAG_KERNEL)", (tVAddr)&_UsertextBase + i*4096);
 161                 MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
 162         }
 163 }
 164
 165 /**
 166  * \brief Cleans up the SMP required mappings
 167  */
 168 void MM_FinishVirtualInit()
 169 {
 170         #if USE_PAE
 171         gaInitPDPT[ 0 ] = 0;
 172         #else
 173         gaInitPageDir[ 0 ] = 0;
 174         #endif
 175 }
 176
 177 /**
 178  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 179  * \brief Called on a page fault
 180  */
 181 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 182 {
 183         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 184
 185         // -- Check for COW --
 186         if( gaPageDir  [Addr>>22] & PF_PRESENT
 187          && gaPageTable[Addr>>12] & PF_PRESENT
 188          && gaPageTable[Addr>>12] & PF_COW )
 189         {
 190                 tPAddr  paddr;
 191                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 192                 {
 193                         gaPageTable[Addr>>12] &= ~PF_COW;
 194                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 195                 }
 196                 else
 197                 {
 198                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 199                         paddr = MM_DuplicatePage( Addr );
 200                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 201                         gaPageTable[Addr>>12] &= PF_USER;
 202                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 203                 }
 204
 205                 INVLPG( Addr & ~0xFFF );
 206                 //LEAVE('-')
 207                 return;
 208         }
 209
 210         // If it was a user, tell the thread handler
 211         if(ErrorCode & 4) {
 212                 Warning("%s %s %s memory%s",
 213                         (ErrorCode&4?"User":"Kernel"),
 214                         (ErrorCode&2?"write to":"read from"),
 215                         (ErrorCode&1?"bad/locked":"non-present"),
 216                         (ErrorCode&16?" (Instruction Fetch)":"")
 217                         );
 218                 Warning("User Pagefault: Instruction at %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 219                 __asm__ __volatile__ ("sti");   // Restart IRQs
 220                 Threads_SegFault(Addr);
 221                 return ;
 222         }
 223
 224         Debug_KernelPanic();
 225
 226         // -- Check Error Code --
 227         if(ErrorCode & 8)
 228                 Warning("Reserved Bits Trashed!");
 229         else
 230         {
 231                 Warning("%s %s %s memory%s",
 232                         (ErrorCode&4?"User":"Kernel"),
 233                         (ErrorCode&2?"write to":"read from"),
 234                         (ErrorCode&1?"bad/locked":"non-present"),
 235                         (ErrorCode&16?" (Instruction Fetch)":"")
 236                         );
 237         }
 238
 239         Log("Code at %p accessed %p", Regs->eip, Addr);
 240         // Print Stack Backtrace
 241         Error_Backtrace(Regs->eip, Regs->ebp);
 242
 243         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 244         if( gaPageDir[Addr>>22] & PF_PRESENT )
 245                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 246
 247         //MM_DumpTables(0, -1);
 248
 249         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 250 }
 251
 252 /**
 253  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 254  * \brief Dumps the layout of the page tables
 255  */
 256 void MM_DumpTables(tVAddr Start, tVAddr End)
 257 {
 258         tVAddr  rangeStart = 0;
 259         tPAddr  expected = 0;
 260         tVAddr  curPos;
 261         Uint    page;
 262         const tPAddr    MASK = ~0xF98;
 263
 264         Start >>= 12;   End >>= 12;
 265
 266         #if 0
 267         Log("Directory Entries:");
 268         for(page = Start >> 10;
 269                 page < (End >> 10)+1;
 270                 page ++)
 271         {
 272                 if(gaPageDir[page])
 273                 {
 274                         Log(" 0x%08x-0x%08x :: 0x%08x",
 275                                 page<<22, ((page+1)<<22)-1,
 276                                 gaPageDir[page]&~0xFFF
 277                                 );
 278                 }
 279         }
 280         #endif
 281
 282         Log("Table Entries:");
 283         for(page = Start, curPos = Start<<12;
 284                 page < End;
 285                 curPos += 0x1000, page++)
 286         {
 287                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 288                 ||  !(gaPageTable[page] & PF_PRESENT)
 289                 ||  (gaPageTable[page] & MASK) != expected)
 290                 {
 291                         if(expected) {
 292                                 Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 293                                         rangeStart, curPos - 1,
 294                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 295                                         (expected & ~0xFFF) - 1,
 296                                         (expected & PF_PAGED ? "p" : "-"),
 297                                         (expected & PF_COW ? "C" : "-"),
 298                                         (expected & PF_USER ? "U" : "-"),
 299                                         (expected & PF_WRITE ? "W" : "-")
 300                                         );
 301                                 expected = 0;
 302                         }
 303                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 304                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 305
 306                         expected = (gaPageTable[page] & MASK);
 307                         rangeStart = curPos;
 308                 }
 309                 if(expected)    expected += 0x1000;
 310         }
 311
 312         if(expected) {
 313                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 314                         rangeStart, curPos - 1,
 315                         gaPageTable[rangeStart>>12] & ~0xFFF,
 316                         (expected & ~0xFFF) - 1,
 317                         (expected & PF_PAGED ? "p" : "-"),
 318                         (expected & PF_COW ? "C" : "-"),
 319                         (expected & PF_USER ? "U" : "-"),
 320                         (expected & PF_WRITE ? "W" : "-")
 321                         );
 322                 expected = 0;
 323         }
 324 }
 325
 326 /**
 327  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 328  */
 329 tPAddr MM_Allocate(tVAddr VAddr)
 330 {
 331         tPAddr  paddr;
 332         //ENTER("xVAddr", VAddr);
 333         //__asm__ __volatile__ ("xchg %bx,%bx");
 334         // Check if the directory is mapped
 335         if( gaPageDir[ VAddr >> 22 ] == 0 )
 336         {
 337                 // Allocate directory
 338                 paddr = MM_AllocPhys();
 339                 //LOG("paddr = 0x%llx (new table)", paddr);
 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
 346                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 347                 // Mark as user
 348                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 349
 350                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 351                 //LOG("Clearing new table");
 352                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 353         }
 354         // Check if the page is already allocated
 355         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 356                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 357                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 358                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 359         }
 360
 361         // Allocate
 362         paddr = MM_AllocPhys();
 363         //LOG("paddr = 0x%llx", paddr);
 364         if( paddr == 0 ) {
 365                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 366                         VAddr, __builtin_return_address(0));
 367                 //LEAVE('i',0);
 368                 return 0;
 369         }
 370         // Map
 371         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 372         // Mark as user
 373         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 374         // Invalidate Cache for address
 375         INVLPG( VAddr & ~0xFFF );
 376
 377         //LEAVE('X', paddr);
 378         return paddr;
 379 }
 380
 381 /**
 382  * \fn void MM_Deallocate(tVAddr VAddr)
 383  */
 384 void MM_Deallocate(tVAddr VAddr)
 385 {
 386         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 387                 Warning("MM_Deallocate - Directory not mapped");
 388                 return;
 389         }
 390
 391         if(gaPageTable[ VAddr >> 12 ] == 0) {
 392                 Warning("MM_Deallocate - Page is not allocated");
 393                 return;
 394         }
 395
 396         // Dereference page
 397         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 398         // Clear page
 399         gaPageTable[ VAddr >> 12 ] = 0;
 400 }
 401
 402 /**
 403  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 404  * \brief Checks if the passed address is accesable
 405  */
 406 tPAddr MM_GetPhysAddr(tVAddr Addr)
 407 {
 408         if( !(gaPageDir[Addr >> 22] & 1) )
 409                 return 0;
 410         if( !(gaPageTable[Addr >> 12] & 1) )
 411                 return 0;
 412         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 413 }
 414
 415
 416 /**
 417  * \fn int MM_IsUser(tVAddr VAddr)
 418  * \brief Checks if a page is user accessable
 419  */
 420 int MM_IsUser(tVAddr VAddr)
 421 {
 422         if( !(gaPageDir[VAddr >> 22] & 1) )
 423                 return 0;
 424         if( !(gaPageTable[VAddr >> 12] & 1) )
 425                 return 0;
 426         if( !(gaPageTable[VAddr >> 12] & PF_USER) )
 427                 return 0;
 428         return 1;
 429 }
 430
 431 /**
 432  * \fn void MM_SetCR3(tPAddr CR3)
 433  * \brief Sets the current process space
 434  */
 435 void MM_SetCR3(tPAddr CR3)
 436 {
 437         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 438 }
 439
 440 /**
 441  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 442  * \brief Map a physical page to a virtual one
 443  */
 444 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 445 {
 446         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 447         // Sanity check
 448         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 449                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 450                 //LEAVE('i', 0);
 451                 return 0;
 452         }
 453
 454         // Align addresses
 455         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 456
 457         // Check if the directory is mapped
 458         if( gaPageDir[ VAddr >> 22 ] == 0 )
 459         {
 460                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 461
 462                 // Mark as user
 463                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 464
 465                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 466                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 467         }
 468         // Check if the page is already allocated
 469         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 470                 Warning("MM_Map - Allocating to used address");
 471                 //LEAVE('i', 0);
 472                 return 0;
 473         }
 474
 475         // Map
 476         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 477         // Mark as user
 478         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 479
 480         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 481         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 482
 483         // Reference
 484         MM_RefPhys( PAddr );
 485
 486         //LOG("INVLPG( 0x%x )", VAddr);
 487         INVLPG( VAddr );
 488
 489         //LEAVE('i', 1);
 490         return 1;
 491 }
 492
 493 /**
 494  * \fn tVAddr MM_ClearUser()
 495  * \brief Clear user's address space
 496  */
 497 tVAddr MM_ClearUser()
 498 {
 499         Uint    i, j;
 500
 501         // Copy Directories
 502         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 503         {
 504                 // Check if directory is not allocated
 505                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 506                         gaPageDir[i] = 0;
 507                         continue;
 508                 }
 509
 510
 511                 for( j = 0; j < 1024; j ++ )
 512                 {
 513                         if( gaPageTable[i*1024+j] & 1 )
 514                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 515                         gaPageTable[i*1024+j] = 0;
 516                 }
 517
 518                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 519                 gaPageDir[i] = 0;
 520                 INVLPG( &gaPageTable[i*1024] );
 521         }
 522         INVLPG( gaPageDir );
 523
 524         return *gpPageCR3;
 525 }
 526
 527 /**
 528  * \fn tPAddr MM_Clone()
 529  * \brief Clone the current address space
 530  */
 531 tPAddr MM_Clone()
 532 {
 533         Uint    i, j;
 534         tVAddr  ret;
 535         Uint    page = 0;
 536         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 537         void    *tmp;
 538
 539         LOCK( &gilTempFractal );
 540
 541         // Create Directory Table
 542         *gpTmpCR3 = MM_AllocPhys() | 3;
 543         INVLPG( gaTmpDir );
 544         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 545         memsetd( gaTmpDir, 0, 1024 );
 546
 547         // Copy Tables
 548         for( i = 0; i < 768; i ++)
 549         {
 550                 // Check if table is allocated
 551                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 552                         gaTmpDir[i] = 0;
 553                         page += 1024;
 554                         continue;
 555                 }
 556
 557                 // Allocate new table
 558                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 559                 INVLPG( &gaTmpTable[page] );
 560                 // Fill
 561                 for( j = 0; j < 1024; j ++, page++ )
 562                 {
 563                         if( !(gaPageTable[page] & PF_PRESENT) ) {
 564                                 gaTmpTable[page] = 0;
 565                                 continue;
 566                         }
 567
 568                         // Refrence old page
 569                         MM_RefPhys( gaPageTable[page] & ~0xFFF );
 570                         // Add to new table
 571                         if(gaPageTable[page] & PF_WRITE) {
 572                                 gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 573                                 gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 574                                 INVLPG( page << 12 );
 575                         }
 576                         else
 577                                 gaTmpTable[page] = gaPageTable[page];
 578                 }
 579         }
 580
 581         // Map in kernel tables (and make fractal mapping)
 582         for( i = 768; i < 1024; i ++ )
 583         {
 584                 // Fractal
 585                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 586                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 587                         continue;
 588                 }
 589
 590                 if( gaPageDir[i] == 0 ) {
 591                         gaTmpDir[i] = 0;
 592                         continue;
 593                 }
 594
 595                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 596                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 597                 gaTmpDir[i] = gaPageDir[i];
 598         }
 599
 600         // Allocate kernel stack
 601         for(i = KERNEL_STACKS >> 22;
 602                 i < KERNEL_STACKS_END >> 22;
 603                 i ++ )
 604         {
 605                 // Check if directory is allocated
 606                 if( (gaPageDir[i] & 1) == 0 ) {
 607                         gaTmpDir[i] = 0;
 608                         continue;
 609                 }
 610
 611                 // We don't care about other kernel stacks, just the current one
 612                 if( i != kStackBase >> 22 ) {
 613                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 614                         gaTmpDir[i] = 0;
 615                         continue;
 616                 }
 617
 618                 // Create a copy
 619                 gaTmpDir[i] = MM_AllocPhys() | 3;
 620                 INVLPG( &gaTmpTable[i*1024] );
 621                 for( j = 0; j < 1024; j ++ )
 622                 {
 623                         // Is the page allocated? If not, skip
 624                         if( !(gaPageTable[i*1024+j] & 1) ) {
 625                                 gaTmpTable[i*1024+j] = 0;
 626                                 continue;
 627                         }
 628
 629                         // We don't care about other kernel stacks
 630                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 631                                 gaTmpTable[i*1024+j] = 0;
 632                                 continue;
 633                         }
 634
 635                         // Allocate page
 636                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 637
 638                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 639
 640                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 641                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 642                         MM_FreeTemp( (Uint)tmp );
 643                 }
 644         }
 645
 646         ret = *gpTmpCR3 & ~0xFFF;
 647         RELEASE( &gilTempFractal );
 648
 649         //LEAVE('x', ret);
 650         return ret;
 651 }
 652
 653 /**
 654  * \fn tVAddr MM_NewKStack()
 655  * \brief Create a new kernel stack
 656  */
 657 tVAddr MM_NewKStack()
 658 {
 659         tVAddr  base = KERNEL_STACKS;
 660         Uint    i;
 661         for(;base<KERNEL_STACKS_END;base+=KERNEL_STACK_SIZE)
 662         {
 663                 if(MM_GetPhysAddr(base) != 0)   continue;
 664                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 665                         MM_Allocate(base+i);
 666                 }
 667                 return base+KERNEL_STACK_SIZE;
 668         }
 669         Warning("MM_NewKStack - No address space left\n");
 670         return 0;
 671 }
 672
 673 /**
 674  * \fn tVAddr MM_NewWorkerStack()
 675  * \brief Creates a new worker stack
 676  */
 677 tVAddr MM_NewWorkerStack()
 678 {
 679         Uint    esp, ebp;
 680         Uint    oldstack;
 681         Uint    base, addr;
 682          int    i, j;
 683         Uint    *tmpPage;
 684         tPAddr  pages[WORKER_STACK_SIZE>>12];
 685
 686         // Get the old ESP and EBP
 687         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 688         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 689
 690         // Find a free worker stack address
 691         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 692         {
 693                 // Used block
 694                 if( gWorkerStacks[base/32] == -1 ) {
 695                         base += 31;     base &= ~31;
 696                         base --;        // Counteracted by the base++
 697                         continue;
 698                 }
 699                 // Used stack
 700                 if( gWorkerStacks[base/32] & (1 << base) ) {
 701                         continue;
 702                 }
 703                 break;
 704         }
 705         if(base >= NUM_WORKER_STACKS) {
 706                 Warning("Uh-oh! Out of worker stacks");
 707                 return 0;
 708         }
 709
 710         // It's ours now!
 711         gWorkerStacks[base/32] |= (1 << base);
 712         // Make life easier for later calls
 713         giLastUsedWorker = base;
 714         // We have one
 715         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 716         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 717
 718         // Acquire the lock for the temp fractal mappings
 719         LOCK(&gilTempFractal);
 720
 721         // Set the temp fractals to TID0's address space
 722         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 723         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 724         INVLPG( gaTmpDir );
 725
 726
 727         // Check if the directory is mapped (we are assuming that the stacks
 728         // will fit neatly in a directory)
 729         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 730         if(gaTmpDir[ base >> 22 ] == 0) {
 731                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 732                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 733         }
 734
 735         // Mapping Time!
 736         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 737         {
 738                 pages[ addr >> 12 ] = MM_AllocPhys();
 739                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 740         }
 741         *gpTmpCR3 = 0;
 742         // Release the temp mapping lock
 743         RELEASE(&gilTempFractal);
 744
 745         // Copy the old stack
 746         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 747         esp = oldstack - esp;   // ESP as an offset in the stack
 748
 749         // Make `base` be the top of the stack
 750         base += WORKER_STACK_SIZE;
 751
 752         i = (WORKER_STACK_SIZE>>12) - 1;
 753         // Copy the contents of the old stack to the new one, altering the addresses
 754         // `addr` is refering to bytes from the stack base (mem downwards)
 755         for(addr = 0; addr < esp; addr += 0x1000)
 756         {
 757                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 758                 tmpPage = (void*)MM_MapTemp( pages[i] );
 759                 // Copy old stack
 760                 for(j = 0; j < 1024; j++)
 761                 {
 762                         // Possible Stack address?
 763                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 764                                 tmpPage[j] = base - (oldstack - stack[j]);
 765                         else    // Seems not, best leave it alone
 766                                 tmpPage[j] = stack[j];
 767                 }
 768                 MM_FreeTemp((tVAddr)tmpPage);
 769                 i --;
 770         }
 771
 772         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 773         return base;
 774 }
 775
 776 /**
 777  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 778  * \brief Sets the flags on a page
 779  */
 780 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 781 {
 782         tTabEnt *ent;
 783         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 784         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 785
 786         ent = &gaPageTable[VAddr >> 12];
 787
 788         // Read-Only
 789         if( Mask & MM_PFLAG_RO )
 790         {
 791                 if( Flags & MM_PFLAG_RO ) {
 792                         *ent &= ~PF_WRITE;
 793                 }
 794                 else {
 795                         gaPageDir[VAddr >> 22] |= PF_WRITE;
 796                         *ent |= PF_WRITE;
 797                 }
 798         }
 799
 800         // Kernel
 801         if( Mask & MM_PFLAG_KERNEL )
 802         {
 803                 if( Flags & MM_PFLAG_KERNEL ) {
 804                         *ent &= ~PF_USER;
 805                 }
 806                 else {
 807                         gaPageDir[VAddr >> 22] |= PF_USER;
 808                         *ent |= PF_USER;
 809                 }
 810         }
 811
 812         // Copy-On-Write
 813         if( Mask & MM_PFLAG_COW )
 814         {
 815                 if( Flags & MM_PFLAG_COW ) {
 816                         *ent &= ~PF_WRITE;
 817                         *ent |= PF_COW;
 818                 }
 819                 else {
 820                         *ent &= ~PF_COW;
 821                         *ent |= PF_WRITE;
 822                 }
 823         }
 824
 825         //Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
 826         //      *ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 827 }
 828
 829 /**
 830  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 831  * \brief Duplicates a virtual page to a physical one
 832  */
 833 tPAddr MM_DuplicatePage(tVAddr VAddr)
 834 {
 835         tPAddr  ret;
 836         Uint    temp;
 837          int    wasRO = 0;
 838
 839         //ENTER("xVAddr", VAddr);
 840
 841         // Check if mapped
 842         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 843         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 844
 845         // Page Align
 846         VAddr &= ~0xFFF;
 847
 848         // Allocate new page
 849         ret = MM_AllocPhys();
 850
 851         // Write-lock the page (to keep data constistent), saving its R/W state
 852         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 853         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 854         INVLPG( VAddr );
 855
 856         // Copy Data
 857         temp = MM_MapTemp(ret);
 858         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 859         MM_FreeTemp(temp);
 860
 861         // Restore Writeable status
 862         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 863         INVLPG(VAddr);
 864
 865         //LEAVE('X', ret);
 866         return ret;
 867 }
 868
 869 /**
 870  * \fn Uint MM_MapTemp(tPAddr PAddr)
 871  * \brief Create a temporary memory mapping
 872  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 873  */
 874 tVAddr MM_MapTemp(tPAddr PAddr)
 875 {
 876          int    i;
 877
 878         //ENTER("XPAddr", PAddr);
 879
 880         PAddr &= ~0xFFF;
 881
 882         //LOG("gilTempMappings = %i", gilTempMappings);
 883
 884         for(;;)
 885         {
 886                 LOCK( &gilTempMappings );
 887
 888                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 889                 {
 890                         // Check if page used
 891                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 892                         // Mark as used
 893                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 894                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 895                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 896                         RELEASE( &gilTempMappings );
 897                         return TEMP_MAP_ADDR + (i << 12);
 898                 }
 899                 RELEASE( &gilTempMappings );
 900                 Threads_Yield();
 901         }
 902 }
 903
 904 /**
 905  * \fn void MM_FreeTemp(tVAddr PAddr)
 906  * \brief Free's a temp mapping
 907  */
 908 void MM_FreeTemp(tVAddr VAddr)
 909 {
 910          int    i = VAddr >> 12;
 911         //ENTER("xVAddr", VAddr);
 912
 913         if(i >= (TEMP_MAP_ADDR >> 12))
 914                 gaPageTable[ i ] = 0;
 915
 916         //LEAVE('-');
 917 }
 918
 919 /**
 920  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 921  * \brief Allocates a contigous number of pages
 922  */
 923 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 924 {
 925          int    i, j;
 926
 927         PAddr &= ~0xFFF;
 928
 929         // Scan List
 930         for( i = 0; i < NUM_HW_PAGES; i ++ )
 931         {
 932                 // Check if addr used
 933                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 934                         continue;
 935
 936                 // Check possible region
 937                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 938                 {
 939                         // If there is an allocated page in the region we are testing, break
 940                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 941                 }
 942                 // Is it all free?
 943                 if( j == Number )
 944                 {
 945                         // Allocate
 946                         for( j = 0; j < Number; j++ ) {
 947                                 MM_RefPhys( PAddr + (j<<12) );
 948                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 949                         }
 950                         return HW_MAP_ADDR + (i<<12);
 951                 }
 952         }
 953         // If we don't find any, return NULL
 954         return 0;
 955 }
 956
 957 /**
 958  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 959  * \brief Allocates DMA physical memory
 960  * \param Pages Number of pages required
 961  * \param MaxBits       Maximum number of bits the physical address can have
 962  * \param PhysAddr      Pointer to the location to place the physical address allocated
 963  * \return Virtual address allocate
 964  */
 965 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 966 {
 967         tPAddr  maxCheck = (1 << MaxBits);
 968         tPAddr  phys;
 969         tVAddr  ret;
 970
 971         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
 972
 973         // Sanity Check
 974         if(MaxBits < 12 || !PhysAddr) {
 975                 LEAVE('i', 0);
 976                 return 0;
 977         }
 978
 979         // Bound
 980         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
 981
 982         // Fast Allocate
 983         if(Pages == 1 && MaxBits >= PHYS_BITS)
 984         {
 985                 phys = MM_AllocPhys();
 986                 *PhysAddr = phys;
 987                 ret = MM_MapHWPages(phys, 1);
 988                 if(ret == 0) {
 989                         MM_DerefPhys(phys);
 990                         LEAVE('i', 0);
 991                         return 0;
 992                 }
 993                 LEAVE('x', ret);
 994                 return ret;
 995         }
 996
 997         // Slow Allocate
 998         phys = MM_AllocPhysRange(Pages, MaxBits);
 999         // - Was it allocated?
1000         if(phys == 0) {
1001                 LEAVE('i', 0);
1002                 return 0;
1003         }
1004
1005         // Allocated successfully, now map
1006         ret = MM_MapHWPages(phys, Pages);
1007         if( ret == 0 ) {
1008                 // If it didn't map, free then return 0
1009                 for(;Pages--;phys+=0x1000)
1010                         MM_DerefPhys(phys);
1011                 LEAVE('i', 0);
1012                 return 0;
1013         }
1014
1015         *PhysAddr = phys;
1016         LEAVE('x', ret);
1017         return ret;
1018 }
1019
1020 /**
1021  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1022  * \brief Unmap a hardware page
1023  */
1024 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1025 {
1026          int    i, j;
1027         // Sanity Check
1028         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
1029
1030         i = VAddr >> 12;
1031
1032         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
1033
1034         for( j = 0; j < Number; j++ )
1035         {
1036                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & ~0xFFF );
1037                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
1038         }
1039
1040         RELEASE( &gilTempMappings );
1041 }
1042
1043 // --- EXPORTS ---
1044 EXPORT(MM_GetPhysAddr);
1045 EXPORT(MM_Map);
1046 //EXPORT(MM_Unmap);
1047 EXPORT(MM_MapHWPages);
1048 EXPORT(MM_AllocDMA);
1049 EXPORT(MM_UnmapHWPages);