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   1
  13 #include <acess.h>
  14 #include <mm_phys.h>
  15 #include <proc.h>
  16
  17 #define KERNEL_STACKS           0xF0000000
  18 #define KERNEL_STACK_SIZE       0x00008000
  19 #define KERNEL_STACKS_END       0xFD000000
  20 #define WORKER_STACKS           0x00100000      // Thread0 Only!
  21 #define WORKER_STACK_SIZE       KERNEL_STACK_SIZE
  22 #define WORKER_STACKS_END       0xB0000000
  23 #define NUM_WORKER_STACKS       ((WORKER_STACKS_END-WORKER_STACKS)/WORKER_STACK_SIZE)
  24 #define PAGE_TABLE_ADDR 0xFD000000
  25 #define PAGE_DIR_ADDR   0xFD3F4000
  26 #define PAGE_CR3_ADDR   0xFD3F4FD0
  27 #define TMP_CR3_ADDR    0xFD3F4FD4      // Part of core instead of temp
  28 #define TMP_DIR_ADDR    0xFD3F5000      // Same
  29 #define TMP_TABLE_ADDR  0xFD400000
  30 #define HW_MAP_ADDR             0xFD800000
  31 #define HW_MAP_MAX              0xFEFF0000
  32 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  33 #define TEMP_MAP_ADDR   0xFEFF0000      // Allows 16 "temp" pages
  34 #define NUM_TEMP_PAGES  16
  35
  36 #define PF_PRESENT      0x1
  37 #define PF_WRITE        0x2
  38 #define PF_USER         0x4
  39 #define PF_COW          0x200
  40 #define PF_PAGED        0x400
  41
  42 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  43
  44 #if USE_PAE
  45 typedef Uint64  tTabEnt;
  46 #else
  47 typedef Uint32  tTabEnt;
  48 #endif
  49
  50 // === IMPORTS ===
  51 extern Uint32   gaInitPageDir[1024];
  52 extern Uint32   gaInitPageTable[1024];
  53 extern void     Threads_SegFault(tVAddr Addr);
  54 extern void     Error_Backtrace(Uint eip, Uint ebp);
  55
  56 // === PROTOTYPES ===
  57 void    MM_PreinitVirtual();
  58 void    MM_InstallVirtual();
  59 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  60 void    MM_DumpTables(tVAddr Start, tVAddr End);
  61 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  62
  63 // === GLOBALS ===
  64 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  65 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  66 #define gaPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  67 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  68 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  69 #define gTmpCR3 ((tTabEnt*)TMP_CR3_ADDR)
  70 //tPAddr        *gaPageTable = (void*)PAGE_TABLE_ADDR;
  71 //tPAddr        *gaPageDir = (void*)PAGE_DIR_ADDR;
  72 //tPAddr        *gaPageCR3 = (void*)PAGE_CR3_ADDR;
  73 //tPAddr        *gaTmpTable = (void*)TMP_TABLE_ADDR;
  74 //tPAddr        *gaTmpDir = (void*)TMP_DIR_ADDR;
  75 //tPAddr        *gTmpCR3 = (void*)TMP_CR3_ADDR;
  76  int    gilTempMappings = 0;
  77  int    gilTempFractal = 0;
  78 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
  79  int    giLastUsedWorker = 0;
  80
  81 // === CODE ===
  82 /**
  83  * \fn void MM_PreinitVirtual()
  84  * \brief Maps the fractal mappings
  85  */
  86 void MM_PreinitVirtual()
  87 {
  88         gaInitPageDir[ 0 ] = 0;
  89         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((Uint)&gaInitPageDir - KERNEL_BASE) | 3;
  90         INVLPG( PAGE_TABLE_ADDR );
  91 }
  92
  93 /**
  94  * \fn void MM_InstallVirtual()
  95  * \brief Sets up the constant page mappings
  96  */
  97 void MM_InstallVirtual()
  98 {
  99          int    i;
 100
 101         // --- Pre-Allocate kernel tables
 102         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 103         {
 104                 if( gaPageDir[ i ] )    continue;
 105                 // Skip stack tables, they are process unique
 106                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 107                         gaPageDir[ i ] = 0;
 108                         continue;
 109                 }
 110                 // Preallocate table
 111                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 112                 INVLPG( &gaPageTable[i*1024] );
 113                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 114         }
 115 }
 116
 117 /**
 118  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 119  * \brief Called on a page fault
 120  */
 121 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 122 {
 123         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 124
 125         // -- Check for COW --
 126         if( gaPageDir  [Addr>>22] & PF_PRESENT
 127          && gaPageTable[Addr>>12] & PF_PRESENT
 128          && gaPageTable[Addr>>12] & PF_COW )
 129         {
 130                 tPAddr  paddr;
 131                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 132                 {
 133                         gaPageTable[Addr>>12] &= ~PF_COW;
 134                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 135                 }
 136                 else
 137                 {
 138                         paddr = MM_DuplicatePage( Addr );
 139                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 140                         gaPageTable[Addr>>12] &= PF_USER;
 141                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 142                 }
 143
 144                 INVLPG( Addr & ~0xFFF );
 145                 //LEAVE('-')
 146                 return;
 147         }
 148
 149         // If it was a user, tell the thread handler
 150         if(ErrorCode & 4) {
 151                 Warning("%s %s %s memory%s",
 152                         (ErrorCode&4?"User":"Kernel"),
 153                         (ErrorCode&2?"write to":"read from"),
 154                         (ErrorCode&1?"bad/locked":"non-present"),
 155                         (ErrorCode&16?" (Instruction Fetch)":"")
 156                         );
 157                 Warning("User Pagefault: Instruction at %p accessed %p", Regs->eip, Addr);
 158                 __asm__ __volatile__ ("sti");   // Restart IRQs
 159                 Threads_SegFault(Addr);
 160                 return ;
 161         }
 162
 163         // -- Check Error Code --
 164         if(ErrorCode & 8)
 165                 Warning("Reserved Bits Trashed!");
 166         else
 167         {
 168                 Warning("%s %s %s memory%s",
 169                         (ErrorCode&4?"User":"Kernel"),
 170                         (ErrorCode&2?"write to":"read from"),
 171                         (ErrorCode&1?"bad/locked":"non-present"),
 172                         (ErrorCode&16?" (Instruction Fetch)":"")
 173                         );
 174         }
 175
 176         Log("Code at %p accessed %p", Regs->eip, Addr);
 177         // Print Stack Backtrace
 178         Error_Backtrace(Regs->eip, Regs->ebp);
 179
 180         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 181         if( gaPageDir[Addr>>22] & PF_PRESENT )
 182                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 183
 184         //MM_DumpTables(0, -1);
 185
 186         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 187 }
 188
 189 /**
 190  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 191  * \brief Dumps the layout of the page tables
 192  */
 193 void MM_DumpTables(tVAddr Start, tVAddr End)
 194 {
 195         tVAddr  rangeStart = 0;
 196         tPAddr  expected = 0;
 197         tVAddr  curPos;
 198         Uint    page;
 199         const tPAddr    MASK = ~0xF98;
 200
 201         Start >>= 12;   End >>= 12;
 202
 203         #if 0
 204         Log("Directory Entries:");
 205         for(page = Start >> 10;
 206                 page < (End >> 10)+1;
 207                 page ++)
 208         {
 209                 if(gaPageDir[page])
 210                 {
 211                         Log(" 0x%08x-0x%08x :: 0x%08x",
 212                                 page<<22, ((page+1)<<22)-1,
 213                                 gaPageDir[page]&~0xFFF
 214                                 );
 215                 }
 216         }
 217         #endif
 218
 219         Log("Table Entries:");
 220         for(page = Start, curPos = Start<<12;
 221                 page < End;
 222                 curPos += 0x1000, page++)
 223         {
 224                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 225                 ||  !(gaPageTable[page] & PF_PRESENT)
 226                 ||  (gaPageTable[page] & MASK) != expected)
 227                 {
 228                         if(expected) {
 229                                 Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 230                                         rangeStart, curPos - 1,
 231                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 232                                         (expected & ~0xFFF) - 1,
 233                                         (expected & PF_PAGED ? "p" : "-"),
 234                                         (expected & PF_COW ? "C" : "-"),
 235                                         (expected & PF_USER ? "U" : "-"),
 236                                         (expected & PF_WRITE ? "W" : "-")
 237                                         );
 238                                 expected = 0;
 239                         }
 240                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 241                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 242
 243                         expected = (gaPageTable[page] & MASK);
 244                         rangeStart = curPos;
 245                 }
 246                 if(expected)    expected += 0x1000;
 247         }
 248
 249         if(expected) {
 250                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 251                         rangeStart, curPos - 1,
 252                         gaPageTable[rangeStart>>12] & ~0xFFF,
 253                         (expected & ~0xFFF) - 1,
 254                         (expected & PF_PAGED ? "p" : "-"),
 255                         (expected & PF_COW ? "C" : "-"),
 256                         (expected & PF_USER ? "U" : "-"),
 257                         (expected & PF_WRITE ? "W" : "-")
 258                         );
 259                 expected = 0;
 260         }
 261 }
 262
 263 /**
 264  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 265  */
 266 tPAddr MM_Allocate(tVAddr VAddr)
 267 {
 268         tPAddr  paddr;
 269         //ENTER("xVAddr", VAddr);
 270         //__asm__ __volatile__ ("xchg %bx,%bx");
 271         // Check if the directory is mapped
 272         if( gaPageDir[ VAddr >> 22 ] == 0 )
 273         {
 274                 // Allocate directory
 275                 paddr = MM_AllocPhys();
 276                 //LOG("paddr = 0x%llx (new table)", paddr);
 277                 if( paddr == 0 ) {
 278                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 279                         LEAVE('i',0);
 280                         return 0;
 281                 }
 282                 // Map
 283                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 284                 // Mark as user
 285                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 286
 287                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 288                 //LOG("Clearing new table");
 289                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 290         }
 291         // Check if the page is already allocated
 292         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 293                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 294                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 295                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 296         }
 297
 298         // Allocate
 299         paddr = MM_AllocPhys();
 300         //LOG("paddr = 0x%llx", paddr);
 301         if( paddr == 0 ) {
 302                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 303                         VAddr, __builtin_return_address(0));
 304                 //LEAVE('i',0);
 305                 return 0;
 306         }
 307         // Map
 308         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 309         // Mark as user
 310         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 311         // Invalidate Cache for address
 312         INVLPG( VAddr & ~0xFFF );
 313
 314         //LEAVE('X', paddr);
 315         return paddr;
 316 }
 317
 318 /**
 319  * \fn void MM_Deallocate(tVAddr VAddr)
 320  */
 321 void MM_Deallocate(tVAddr VAddr)
 322 {
 323         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 324                 Warning("MM_Deallocate - Directory not mapped");
 325                 return;
 326         }
 327
 328         if(gaPageTable[ VAddr >> 12 ] == 0) {
 329                 Warning("MM_Deallocate - Page is not allocated");
 330                 return;
 331         }
 332
 333         // Dereference page
 334         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 335         // Clear page
 336         gaPageTable[ VAddr >> 12 ] = 0;
 337 }
 338
 339 /**
 340  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 341  * \brief Checks if the passed address is accesable
 342  */
 343 tPAddr MM_GetPhysAddr(tVAddr Addr)
 344 {
 345         if( !(gaPageDir[Addr >> 22] & 1) )
 346                 return 0;
 347         if( !(gaPageTable[Addr >> 12] & 1) )
 348                 return 0;
 349         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 350 }
 351
 352
 353 /**
 354  * \fn int MM_IsUser(tVAddr VAddr)
 355  * \brief Checks if a page is user accessable
 356  */
 357 int MM_IsUser(tVAddr VAddr)
 358 {
 359         if( !(gaPageDir[VAddr >> 22] & 1) )
 360                 return 0;
 361         if( !(gaPageTable[VAddr >> 12] & 1) )
 362                 return 0;
 363         if( !(gaPageTable[VAddr >> 12] & PF_USER) )
 364                 return 0;
 365         return 1;
 366 }
 367
 368 /**
 369  * \fn void MM_SetCR3(tPAddr CR3)
 370  * \brief Sets the current process space
 371  */
 372 void MM_SetCR3(tPAddr CR3)
 373 {
 374         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 375 }
 376
 377 /**
 378  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 379  * \brief Map a physical page to a virtual one
 380  */
 381 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 382 {
 383         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 384         // Sanity check
 385         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 386                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 387                 //LEAVE('i', 0);
 388                 return 0;
 389         }
 390
 391         // Align addresses
 392         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 393
 394         // Check if the directory is mapped
 395         if( gaPageDir[ VAddr >> 22 ] == 0 )
 396         {
 397                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 398
 399                 // Mark as user
 400                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 401
 402                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 403                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 404         }
 405         // Check if the page is already allocated
 406         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 407                 Warning("MM_Map - Allocating to used address");
 408                 //LEAVE('i', 0);
 409                 return 0;
 410         }
 411
 412         // Map
 413         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 414         // Mark as user
 415         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 416
 417         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 418         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 419
 420         // Reference
 421         MM_RefPhys( PAddr );
 422
 423         //LOG("INVLPG( 0x%x )", VAddr);
 424         INVLPG( VAddr );
 425
 426         //LEAVE('i', 1);
 427         return 1;
 428 }
 429
 430 /**
 431  * \fn tVAddr MM_ClearUser()
 432  * \brief Clear user's address space
 433  */
 434 tVAddr MM_ClearUser()
 435 {
 436         Uint    i, j;
 437
 438         // Copy Directories
 439         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 440         {
 441                 // Check if directory is not allocated
 442                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 443                         gaPageDir[i] = 0;
 444                         continue;
 445                 }
 446
 447
 448                 for( j = 0; j < 1024; j ++ )
 449                 {
 450                         if( gaPageTable[i*1024+j] & 1 )
 451                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 452                         gaPageTable[i*1024+j] = 0;
 453                 }
 454
 455                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 456                 gaPageDir[i] = 0;
 457                 INVLPG( &gaPageTable[i*1024] );
 458         }
 459         INVLPG( gaPageDir );
 460
 461         return *gaPageCR3;
 462 }
 463
 464 /**
 465  * \fn tPAddr MM_Clone()
 466  * \brief Clone the current address space
 467  */
 468 tPAddr MM_Clone()
 469 {
 470         Uint    i, j;
 471         tVAddr  ret;
 472         Uint    page = 0;
 473         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 474         void    *tmp;
 475
 476         LOCK( &gilTempFractal );
 477
 478         // Create Directory Table
 479         *gTmpCR3 = MM_AllocPhys() | 3;
 480         INVLPG( gaTmpDir );
 481         //LOG("Allocated Directory (%x)", *gTmpCR3);
 482         memsetd( gaTmpDir, 0, 1024 );
 483
 484         // Copy Tables
 485         for(i=0;i<768;i++)
 486         {
 487                 // Check if table is allocated
 488                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 489                         gaTmpDir[i] = 0;
 490                         page += 1024;
 491                         continue;
 492                 }
 493
 494                 // Allocate new table
 495                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 496                 INVLPG( &gaTmpTable[page] );
 497                 // Fill
 498                 for( j = 0; j < 1024; j ++, page++ )
 499                 {
 500                         if( !(gaPageTable[page] & PF_PRESENT) ) {
 501                                 gaTmpTable[page] = 0;
 502                                 continue;
 503                         }
 504
 505                         // Refrence old page
 506                         MM_RefPhys( gaPageTable[page] & ~0xFFF );
 507                         // Add to new table
 508                         if(gaPageTable[page] & PF_WRITE) {
 509                                 gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 510                                 gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 511                                 INVLPG( page << 12 );
 512                         }
 513                         else
 514                                 gaTmpTable[page] = gaPageTable[page];
 515                 }
 516         }
 517
 518         // Map in kernel tables (and make fractal mapping)
 519         for( i = 768; i < 1024; i ++ )
 520         {
 521                 // Fractal
 522                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 523                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 524                         continue;
 525                 }
 526
 527                 if( gaPageDir[i] == 0 ) {
 528                         gaTmpDir[i] = 0;
 529                         continue;
 530                 }
 531
 532                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 533                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 534                 gaTmpDir[i] = gaPageDir[i];
 535         }
 536
 537         // Allocate kernel stack
 538         for(i = KERNEL_STACKS >> 22;
 539                 i < KERNEL_STACKS_END >> 22;
 540                 i ++ )
 541         {
 542                 // Check if directory is allocated
 543                 if( (gaPageDir[i] & 1) == 0 ) {
 544                         gaTmpDir[i] = 0;
 545                         continue;
 546                 }
 547
 548                 // We don't care about other kernel stacks, just the current one
 549                 if( i != kStackBase >> 22 ) {
 550                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 551                         gaTmpDir[i] = 0;
 552                         continue;
 553                 }
 554
 555                 // Create a copy
 556                 gaTmpDir[i] = MM_AllocPhys() | 3;
 557                 INVLPG( &gaTmpTable[i*1024] );
 558                 for( j = 0; j < 1024; j ++ )
 559                 {
 560                         // Is the page allocated? If not, skip
 561                         if( !(gaPageTable[i*1024+j] & 1) ) {
 562                                 gaTmpTable[i*1024+j] = 0;
 563                                 continue;
 564                         }
 565
 566                         // We don't care about other kernel stacks
 567                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 568                                 gaTmpTable[i*1024+j] = 0;
 569                                 continue;
 570                         }
 571
 572                         // Allocate page
 573                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 574
 575                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 576
 577                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 578                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 579                         MM_FreeTemp( (Uint)tmp );
 580                 }
 581         }
 582
 583         ret = *gTmpCR3 & ~0xFFF;
 584         RELEASE( &gilTempFractal );
 585
 586         //LEAVE('x', ret);
 587         return ret;
 588 }
 589
 590 /**
 591  * \fn tVAddr MM_NewKStack()
 592  * \brief Create a new kernel stack
 593  */
 594 tVAddr MM_NewKStack()
 595 {
 596         tVAddr  base = KERNEL_STACKS;
 597         Uint    i;
 598         for(;base<KERNEL_STACKS_END;base+=KERNEL_STACK_SIZE)
 599         {
 600                 if(MM_GetPhysAddr(base) != 0)   continue;
 601                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 602                         MM_Allocate(base+i);
 603                 }
 604                 return base+KERNEL_STACK_SIZE;
 605         }
 606         Warning("MM_NewKStack - No address space left\n");
 607         return 0;
 608 }
 609
 610 /**
 611  * \fn tVAddr MM_NewWorkerStack()
 612  * \brief Creates a new worker stack
 613  */
 614 tVAddr MM_NewWorkerStack()
 615 {
 616         Uint    esp, ebp;
 617         Uint    oldstack;
 618         Uint    base, addr;
 619          int    i, j;
 620         Uint    *tmpPage;
 621         tPAddr  pages[WORKER_STACK_SIZE>>12];
 622
 623         // Get the old ESP and EBP
 624         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 625         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 626
 627         // Find a free worker stack address
 628         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 629         {
 630                 // Used block
 631                 if( gWorkerStacks[base/32] == -1 ) {
 632                         base += 31;     base &= ~31;
 633                         base --;        // Counteracted by the base++
 634                         continue;
 635                 }
 636                 // Used stack
 637                 if( gWorkerStacks[base/32] & (1 << base) ) {
 638                         continue;
 639                 }
 640                 break;
 641         }
 642         if(base >= NUM_WORKER_STACKS) {
 643                 Warning("Uh-oh! Out of worker stacks");
 644                 return 0;
 645         }
 646
 647         // It's ours now!
 648         gWorkerStacks[base/32] |= (1 << base);
 649         // Make life easier for later calls
 650         giLastUsedWorker = base;
 651         // We have one
 652         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 653         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 654
 655         // Acquire the lock for the temp fractal mappings
 656         LOCK(&gilTempFractal);
 657
 658         // Set the temp fractals to TID0's address space
 659         *gTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 660         //Log(" MM_NewWorkerStack: *gTmpCR3 = 0x%x", *gTmpCR3);
 661         INVLPG( gaTmpDir );
 662
 663
 664         // Check if the directory is mapped (we are assuming that the stacks
 665         // will fit neatly in a directory)
 666         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 667         if(gaTmpDir[ base >> 22 ] == 0) {
 668                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 669                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 670         }
 671
 672         // Mapping Time!
 673         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 674         {
 675                 pages[ addr >> 12 ] = MM_AllocPhys();
 676                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 677         }
 678         *gTmpCR3 = 0;
 679         // Release the temp mapping lock
 680         RELEASE(&gilTempFractal);
 681
 682         // Copy the old stack
 683         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 684         esp = oldstack - esp;   // ESP as an offset in the stack
 685
 686         // Make `base` be the top of the stack
 687         base += WORKER_STACK_SIZE;
 688
 689         i = (WORKER_STACK_SIZE>>12) - 1;
 690         // Copy the contents of the old stack to the new one, altering the addresses
 691         // `addr` is refering to bytes from the stack base (mem downwards)
 692         for(addr = 0; addr < esp; addr += 0x1000)
 693         {
 694                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 695                 tmpPage = (void*)MM_MapTemp( pages[i] );
 696                 // Copy old stack
 697                 for(j = 0; j < 1024; j++)
 698                 {
 699                         // Possible Stack address?
 700                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 701                                 tmpPage[j] = base - (oldstack - stack[j]);
 702                         else    // Seems not, best leave it alone
 703                                 tmpPage[j] = stack[j];
 704                 }
 705                 MM_FreeTemp((tVAddr)tmpPage);
 706                 i --;
 707         }
 708
 709         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 710         return base;
 711 }
 712
 713 /**
 714  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 715  * \brief Sets the flags on a page
 716  */
 717 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 718 {
 719         tTabEnt *ent;
 720         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 721         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 722
 723         ent = &gaPageTable[VAddr >> 12];
 724
 725         // Read-Only
 726         if( Mask & MM_PFLAG_RO )
 727         {
 728                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 729                 else    *ent |= PF_WRITE;
 730         }
 731
 732         // Kernel
 733         if( Mask & MM_PFLAG_KERNEL )
 734         {
 735                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 736                 else    *ent |= PF_USER;
 737         }
 738
 739         // Copy-On-Write
 740         if( Mask & MM_PFLAG_COW )
 741         {
 742                 if( Flags & MM_PFLAG_COW ) {
 743                         *ent &= ~PF_WRITE;
 744                         *ent |= PF_COW;
 745                 }
 746                 else {
 747                         *ent &= ~PF_COW;
 748                         *ent |= PF_WRITE;
 749                 }
 750         }
 751 }
 752
 753 /**
 754  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 755  * \brief Duplicates a virtual page to a physical one
 756  */
 757 tPAddr MM_DuplicatePage(tVAddr VAddr)
 758 {
 759         tPAddr  ret;
 760         Uint    temp;
 761          int    wasRO = 0;
 762
 763         // Check if mapped
 764         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 765         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 766
 767         // Page Align
 768         VAddr &= ~0xFFF;
 769
 770         // Allocate new page
 771         ret = MM_AllocPhys();
 772
 773         // Write-lock the page (to keep data constistent), saving its R/W state
 774         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 775         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 776         INVLPG( VAddr );
 777
 778         // Copy Data
 779         temp = MM_MapTemp(ret);
 780         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 781         MM_FreeTemp(temp);
 782
 783         // Restore Writeable status
 784         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 785         INVLPG(VAddr);
 786
 787         return ret;
 788 }
 789
 790 /**
 791  * \fn Uint MM_MapTemp(tPAddr PAddr)
 792  * \brief Create a temporary memory mapping
 793  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 794  */
 795 tVAddr MM_MapTemp(tPAddr PAddr)
 796 {
 797          int    i;
 798
 799         //ENTER("XPAddr", PAddr);
 800
 801         PAddr &= ~0xFFF;
 802
 803         //LOG("gilTempMappings = %i", gilTempMappings);
 804
 805         for(;;)
 806         {
 807                 LOCK( &gilTempMappings );
 808
 809                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 810                 {
 811                         // Check if page used
 812                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 813                         // Mark as used
 814                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 815                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 816                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 817                         RELEASE( &gilTempMappings );
 818                         return TEMP_MAP_ADDR + (i << 12);
 819                 }
 820                 RELEASE( &gilTempMappings );
 821                 Threads_Yield();
 822         }
 823 }
 824
 825 /**
 826  * \fn void MM_FreeTemp(tVAddr PAddr)
 827  * \brief Free's a temp mapping
 828  */
 829 void MM_FreeTemp(tVAddr VAddr)
 830 {
 831          int    i = VAddr >> 12;
 832         //ENTER("xVAddr", VAddr);
 833
 834         if(i >= (TEMP_MAP_ADDR >> 12))
 835                 gaPageTable[ i ] = 0;
 836
 837         //LEAVE('-');
 838 }
 839
 840 /**
 841  * \fn tVAddr MM_MapHWPage(tPAddr PAddr, Uint Number)
 842  * \brief Allocates a contigous number of pages
 843  */
 844 tVAddr MM_MapHWPage(tPAddr PAddr, Uint Number)
 845 {
 846          int    i, j;
 847
 848         PAddr &= ~0xFFF;
 849
 850         // Scan List
 851         for( i = 0; i < NUM_HW_PAGES; i ++ )
 852         {
 853                 // Check if addr used
 854                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 855                         continue;
 856
 857                 // Check possible region
 858                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 859                 {
 860                         // If there is an allocated page in the region we are testing, break
 861                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 862                 }
 863                 // Is it all free?
 864                 if( j == Number )
 865                 {
 866                         // Allocate
 867                         for( j = 0; j < Number; j++ ) {
 868                                 MM_RefPhys( PAddr + (j<<12) );
 869                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 870                         }
 871                         return HW_MAP_ADDR + (i<<12);
 872                 }
 873         }
 874         // If we don't find any, return NULL
 875         return 0;
 876 }
 877
 878 /**
 879  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 880  * \brief Allocates DMA physical memory
 881  * \param Pages Number of pages required
 882  * \param MaxBits       Maximum number of bits the physical address can have
 883  * \param PhysAddr      Pointer to the location to place the physical address allocated
 884  * \return Virtual address allocate
 885  */
 886 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 887 {
 888         tPAddr  maxCheck = (1 << MaxBits);
 889         tPAddr  phys;
 890         tVAddr  ret;
 891
 892         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
 893
 894         // Sanity Check
 895         if(MaxBits < 12 || !PhysAddr) {
 896                 LEAVE('i', 0);
 897                 return 0;
 898         }
 899
 900         // Bound
 901         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
 902
 903         // Fast Allocate
 904         if(Pages == 1 && MaxBits >= PHYS_BITS)
 905         {
 906                 phys = MM_AllocPhys();
 907                 *PhysAddr = phys;
 908                 ret = MM_MapHWPage(phys, 1);
 909                 if(ret == 0) {
 910                         MM_DerefPhys(phys);
 911                         LEAVE('i', 0);
 912                         return 0;
 913                 }
 914                 LEAVE('x', ret);
 915                 return ret;
 916         }
 917
 918         // Slow Allocate
 919         phys = MM_AllocPhysRange(Pages);
 920         // - Was it allocated?
 921         if(phys == 0) {
 922                 LEAVE('i', 0);
 923                 return 0;
 924         }
 925         // - Check if the memory is OK
 926         if(phys + (Pages-1)*0x1000 > maxCheck)
 927         {
 928                 // Deallocate and return 0
 929                 for(;Pages--;phys+=0x1000)
 930                         MM_DerefPhys(phys);
 931                 LEAVE('i', 0);
 932                 return 0;
 933         }
 934
 935         // Allocated successfully, now map
 936         ret = MM_MapHWPage(phys, Pages);
 937         if( ret == 0 ) {
 938                 // If it didn't map, free then return 0
 939                 for(;Pages--;phys+=0x1000)
 940                         MM_DerefPhys(phys);
 941                 LEAVE('i', 0);
 942                 return 0;
 943         }
 944
 945         *PhysAddr = phys;
 946         LEAVE('x', ret);
 947         return ret;
 948 }
 949
 950 /**
 951  * \fn void MM_UnmapHWPage(tVAddr VAddr, Uint Number)
 952  * \brief Unmap a hardware page
 953  */
 954 void MM_UnmapHWPage(tVAddr VAddr, Uint Number)
 955 {
 956          int    i, j;
 957         // Sanity Check
 958         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 959
 960         i = VAddr >> 12;
 961
 962         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 963
 964         for( j = 0; j < Number; j++ )
 965         {
 966                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 967                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 968         }
 969
 970         RELEASE( &gilTempMappings );
 971 }
 972
 973 // --- EXPORTS ---
 974 EXPORT(MM_GetPhysAddr);
 975 EXPORT(MM_Map);
 976 //EXPORT(MM_Unmap);
 977 EXPORT(MM_MapHWPage);
 978 EXPORT(MM_AllocDMA);
 979 EXPORT(MM_UnmapHWPage);