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 <common.h>
  14 #include <mm_phys.h>
  15 #include <proc.h>
  16
  17 #define KERNEL_STACKS           0xF0000000
  18 #define KERNEL_STACK_SIZE       0x00002000
  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 // === IMPORTS ===
  45 extern Uint32   gaInitPageDir[1024];
  46 extern Uint32   gaInitPageTable[1024];
  47 extern void     Threads_SegFault(Uint Addr);
  48 extern void     Error_Backtrace(Uint eip, Uint ebp);
  49
  50 // === PROTOTYPES ===
  51 void    MM_PreinitVirtual();
  52 void    MM_InstallVirtual();
  53 void    MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs);
  54 void    MM_DumpTables(tVAddr Start, tVAddr End);
  55 tPAddr  MM_DuplicatePage(Uint VAddr);
  56
  57 // === GLOBALS ===
  58 tPAddr  *gaPageTable = (void*)PAGE_TABLE_ADDR;
  59 tPAddr  *gaPageDir = (void*)PAGE_DIR_ADDR;
  60 tPAddr  *gaPageCR3 = (void*)PAGE_CR3_ADDR;
  61 tPAddr  *gaTmpTable = (void*)TMP_TABLE_ADDR;
  62 tPAddr  *gaTmpDir = (void*)TMP_DIR_ADDR;
  63 tPAddr  *gTmpCR3 = (void*)TMP_CR3_ADDR;
  64  int    gilTempMappings = 0;
  65  int    gilTempFractal = 0;
  66 Uint32  gWorkerStacks[NUM_WORKER_STACKS/32];
  67  int    giLastUsedWorker = 0;
  68
  69 // === CODE ===
  70 /**
  71  * \fn void MM_PreinitVirtual()
  72  * \brief Maps the fractal mappings
  73  */
  74 void MM_PreinitVirtual()
  75 {
  76         gaInitPageDir[ 0 ] = 0;
  77         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((Uint)&gaInitPageDir - KERNEL_BASE) | 3;
  78 }
  79
  80 /**
  81  * \fn void MM_InstallVirtual()
  82  * \brief Sets up the constant page mappings
  83  */
  84 void MM_InstallVirtual()
  85 {
  86          int    i;
  87
  88         // --- Pre-Allocate kernel tables
  89         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
  90         {
  91                 if( gaPageDir[ i ] )    continue;
  92                 // Skip stack tables, they are process unique
  93                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
  94                         gaPageDir[ i ] = 0;
  95                         continue;
  96                 }
  97                 // Preallocate table
  98                 gaPageDir[ i ] = MM_AllocPhys() | 3;
  99                 INVLPG( &gaPageTable[i*1024] );
 100                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 101         }
 102 }
 103
 104 /**
 105  * \fn void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
 106  * \brief Called on a page fault
 107  */
 108 void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
 109 {
 110         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 111
 112         // -- Check for COW --
 113         if( gaPageDir  [Addr>>22] & PF_PRESENT
 114          && gaPageTable[Addr>>12] & PF_PRESENT
 115          && gaPageTable[Addr>>12] & PF_COW )
 116         {
 117                 tPAddr  paddr;
 118                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 119                 {
 120                         gaPageTable[Addr>>12] &= ~PF_COW;
 121                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 122                 }
 123                 else
 124                 {
 125                         paddr = MM_DuplicatePage( Addr );
 126                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 127                         gaPageTable[Addr>>12] &= PF_USER;
 128                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 129                 }
 130
 131                 INVLPG( Addr & ~0xFFF );
 132                 //LEAVE('-')
 133                 return;
 134         }
 135
 136         // If it was a user, tell the thread handler
 137         if(ErrorCode & 4) {
 138                 Warning("%s %s %s memory%s",
 139                         (ErrorCode&4?"User":"Kernel"),
 140                         (ErrorCode&2?"write to":"read from"),
 141                         (ErrorCode&1?"bad/locked":"non-present"),
 142                         (ErrorCode&16?" (Instruction Fetch)":"")
 143                         );
 144                 Warning("User Pagefault: Instruction at %p accessed %p", Regs->eip, Addr);
 145                 __asm__ __volatile__ ("sti");   // Restart IRQs
 146                 Threads_SegFault(Addr);
 147                 return ;
 148         }
 149
 150         // -- Check Error Code --
 151         if(ErrorCode & 8)
 152                 Warning("Reserved Bits Trashed!");
 153         else
 154         {
 155                 Warning("%s %s %s memory%s",
 156                         (ErrorCode&4?"User":"Kernel"),
 157                         (ErrorCode&2?"write to":"read from"),
 158                         (ErrorCode&1?"bad/locked":"non-present"),
 159                         (ErrorCode&16?" (Instruction Fetch)":"")
 160                         );
 161         }
 162
 163         Log("Code at %p accessed %p", Regs->eip, Addr);
 164         // Print Stack Backtrace
 165         Error_Backtrace(Regs->eip, Regs->ebp);
 166
 167         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 168         if( gaPageDir[Addr>>22] & PF_PRESENT )
 169                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 170
 171         MM_DumpTables(0, -1);
 172
 173         Panic("Page Fault at 0x%x\n", Regs->eip);
 174 }
 175
 176 /**
 177  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 178  * \brief Dumps the layout of the page tables
 179  */
 180 void MM_DumpTables(tVAddr Start, tVAddr End)
 181 {
 182         tVAddr  rangeStart = 0;
 183         tPAddr  expected = 0;
 184         tVAddr  curPos;
 185         Uint    page;
 186         const tPAddr    MASK = ~0xF98;
 187
 188         Start >>= 12;   End >>= 12;
 189
 190         #if 0
 191         Log("Directory Entries:");
 192         for(page = Start >> 10;
 193                 page < (End >> 10)+1;
 194                 page ++)
 195         {
 196                 if(gaPageDir[page])
 197                 {
 198                         Log(" 0x%08x-0x%08x :: 0x%08x",
 199                                 page<<22, ((page+1)<<22)-1,
 200                                 gaPageDir[page]&~0xFFF
 201                                 );
 202                 }
 203         }
 204         #endif
 205
 206         Log("Table Entries:");
 207         for(page = Start, curPos = Start<<12;
 208                 page < End;
 209                 curPos += 0x1000, page++)
 210         {
 211                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 212                 ||  !(gaPageTable[page] & PF_PRESENT)
 213                 ||  (gaPageTable[page] & MASK) != expected)
 214                 {
 215                         if(expected) {
 216                                 Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 217                                         rangeStart, curPos - 1,
 218                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 219                                         (expected & ~0xFFF) - 1,
 220                                         (expected & PF_PAGED ? "p" : "-"),
 221                                         (expected & PF_COW ? "C" : "-"),
 222                                         (expected & PF_USER ? "U" : "-"),
 223                                         (expected & PF_WRITE ? "W" : "-")
 224                                         );
 225                                 expected = 0;
 226                         }
 227                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 228                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 229
 230                         expected = (gaPageTable[page] & MASK);
 231                         rangeStart = curPos;
 232                 }
 233                 if(expected)    expected += 0x1000;
 234         }
 235
 236         if(expected) {
 237                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 238                         rangeStart, curPos - 1,
 239                         gaPageTable[rangeStart>>12] & ~0xFFF,
 240                         (expected & ~0xFFF) - 1,
 241                         (expected & PF_PAGED ? "p" : "-"),
 242                         (expected & PF_COW ? "C" : "-"),
 243                         (expected & PF_USER ? "U" : "-"),
 244                         (expected & PF_WRITE ? "W" : "-")
 245                         );
 246                 expected = 0;
 247         }
 248 }
 249
 250 /**
 251  * \fn tPAddr MM_Allocate(Uint VAddr)
 252  */
 253 tPAddr MM_Allocate(Uint VAddr)
 254 {
 255         tPAddr  paddr;
 256         // Check if the directory is mapped
 257         if( gaPageDir[ VAddr >> 22 ] == 0 )
 258         {
 259                 // Allocate directory
 260                 paddr = MM_AllocPhys();
 261                 if( paddr == 0 ) {
 262                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 263                         return 0;
 264                 }
 265                 // Map
 266                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 267                 // Mark as user
 268                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 269
 270                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 271                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 272         }
 273         // Check if the page is already allocated
 274         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 275                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 276                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 277         }
 278
 279         // Allocate
 280         paddr = MM_AllocPhys();
 281         if( paddr == 0 ) {
 282                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 283                         VAddr, __builtin_return_address(0));
 284                 return 0;
 285         }
 286         // Map
 287         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 288         // Mark as user
 289         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 290         // Invalidate Cache for address
 291         INVLPG( VAddr & ~0xFFF );
 292
 293         return paddr;
 294 }
 295
 296 /**
 297  * \fn void MM_Deallocate(Uint VAddr)
 298  */
 299 void MM_Deallocate(Uint VAddr)
 300 {
 301         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 302                 Warning("MM_Deallocate - Directory not mapped");
 303                 return;
 304         }
 305
 306         if(gaPageTable[ VAddr >> 12 ] == 0) {
 307                 Warning("MM_Deallocate - Page is not allocated");
 308                 return;
 309         }
 310
 311         // Dereference page
 312         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 313         // Clear page
 314         gaPageTable[ VAddr >> 12 ] = 0;
 315 }
 316
 317 /**
 318  * \fn tPAddr MM_GetPhysAddr(Uint Addr)
 319  * \brief Checks if the passed address is accesable
 320  */
 321 tPAddr MM_GetPhysAddr(Uint Addr)
 322 {
 323         if( !(gaPageDir[Addr >> 22] & 1) )
 324                 return 0;
 325         if( !(gaPageTable[Addr >> 12] & 1) )
 326                 return 0;
 327         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 328 }
 329
 330 /**
 331  * \fn void MM_SetCR3(Uint CR3)
 332  * \brief Sets the current process space
 333  */
 334 void MM_SetCR3(Uint CR3)
 335 {
 336         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 337 }
 338
 339 /**
 340  * \fn int MM_Map(Uint VAddr, tPAddr PAddr)
 341  * \brief Map a physical page to a virtual one
 342  */
 343 int MM_Map(Uint VAddr, tPAddr PAddr)
 344 {
 345         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 346         // Sanity check
 347         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 348                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 349                 //LEAVE('i', 0);
 350                 return 0;
 351         }
 352
 353         // Align addresses
 354         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 355
 356         // Check if the directory is mapped
 357         if( gaPageDir[ VAddr >> 22 ] == 0 )
 358         {
 359                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 360
 361                 // Mark as user
 362                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 363
 364                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 365                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 366         }
 367         // Check if the page is already allocated
 368         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 369                 Warning("MM_Map - Allocating to used address");
 370                 //LEAVE('i', 0);
 371                 return 0;
 372         }
 373
 374         // Map
 375         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 376         // Mark as user
 377         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 378
 379         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 380         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 381
 382         // Reference
 383         MM_RefPhys( PAddr );
 384
 385         //LOG("INVLPG( 0x%x )", VAddr);
 386         INVLPG( VAddr );
 387
 388         //LEAVE('i', 1);
 389         return 1;
 390 }
 391
 392 /**
 393  * \fn Uint MM_ClearUser()
 394  * \brief Clear user's address space
 395  */
 396 Uint MM_ClearUser()
 397 {
 398         Uint    i, j;
 399
 400         // Copy Directories
 401         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 402         {
 403                 // Check if directory is not allocated
 404                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 405                         gaPageDir[i] = 0;
 406                         continue;
 407                 }
 408
 409
 410                 for( j = 0; j < 1024; j ++ )
 411                 {
 412                         if( gaPageTable[i*1024+j] & 1 )
 413                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 414                         gaPageTable[i*1024+j] = 0;
 415                 }
 416
 417                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 418                 gaPageDir[i] = 0;
 419                 INVLPG( &gaPageTable[i*1024] );
 420         }
 421         INVLPG( gaPageDir );
 422
 423         return *gaPageCR3;
 424 }
 425
 426 /**
 427  * \fn Uint MM_Clone()
 428  * \brief Clone the current address space
 429  */
 430 Uint MM_Clone()
 431 {
 432         Uint    i, j;
 433         Uint    ret;
 434         Uint    page = 0;
 435         Uint    kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 436         void    *tmp;
 437
 438         LOCK( &gilTempFractal );
 439
 440         // Create Directory Table
 441         *gTmpCR3 = MM_AllocPhys() | 3;
 442         INVLPG( gaTmpDir );
 443         //LOG("Allocated Directory (%x)", *gTmpCR3);
 444         memsetd( gaTmpDir, 0, 1024 );
 445
 446         // Copy Tables
 447         for(i=0;i<768;i++)
 448         {
 449                 // Check if table is allocated
 450                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 451                         gaTmpDir[i] = 0;
 452                         page += 1024;
 453                         continue;
 454                 }
 455
 456                 // Allocate new table
 457                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 458                 INVLPG( &gaTmpTable[page] );
 459                 // Fill
 460                 for( j = 0; j < 1024; j ++, page++ )
 461                 {
 462                         if( !(gaPageTable[page] & PF_PRESENT) ) {
 463                                 gaTmpTable[page] = 0;
 464                                 continue;
 465                         }
 466
 467                         // Refrence old page
 468                         MM_RefPhys( gaPageTable[page] & ~0xFFF );
 469                         // Add to new table
 470                         if(gaPageTable[page] & PF_WRITE) {
 471                                 gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 472                                 gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 473                                 INVLPG( page << 12 );
 474                         }
 475                         else
 476                                 gaTmpTable[page] = gaPageTable[page];
 477                 }
 478         }
 479
 480         // Map in kernel tables (and make fractal mapping)
 481         for( i = 768; i < 1024; i ++ )
 482         {
 483                 // Fractal
 484                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 485                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 486                         continue;
 487                 }
 488
 489                 if( gaPageDir[i] == 0 ) {
 490                         gaTmpDir[i] = 0;
 491                         continue;
 492                 }
 493
 494                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 495                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 496                 gaTmpDir[i] = gaPageDir[i];
 497         }
 498
 499         // Allocate kernel stack
 500         for(i = KERNEL_STACKS >> 22;
 501                 i < KERNEL_STACKS_END >> 22;
 502                 i ++ )
 503         {
 504                 // Check if directory is allocated
 505                 if( (gaPageDir[i] & 1) == 0 ) {
 506                         gaTmpDir[i] = 0;
 507                         continue;
 508                 }
 509
 510                 // We don't care about other kernel stacks, just the current one
 511                 if( i != kStackBase >> 22 ) {
 512                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 513                         gaTmpDir[i] = 0;
 514                         continue;
 515                 }
 516
 517                 // Create a copy
 518                 gaTmpDir[i] = MM_AllocPhys() | 3;
 519                 INVLPG( &gaTmpTable[i*1024] );
 520                 for( j = 0; j < 1024; j ++ )
 521                 {
 522                         // Is the page allocated? If not, skip
 523                         if( !(gaPageTable[i*1024+j] & 1) ) {
 524                                 gaTmpTable[i*1024+j] = 0;
 525                                 continue;
 526                         }
 527
 528                         // We don't care about other kernel stacks
 529                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 530                                 gaTmpTable[i*1024+j] = 0;
 531                                 continue;
 532                         }
 533
 534                         // Allocate page
 535                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 536
 537                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 538
 539                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 540                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 541                         MM_FreeTemp( (Uint)tmp );
 542                 }
 543         }
 544
 545         ret = *gTmpCR3 & ~0xFFF;
 546         RELEASE( &gilTempFractal );
 547
 548         //LEAVE('x', ret);
 549         return ret;
 550 }
 551
 552 /**
 553  * \fn Uint MM_NewKStack()
 554  * \brief Create a new kernel stack
 555  */
 556 Uint MM_NewKStack()
 557 {
 558         Uint    base = KERNEL_STACKS;
 559         Uint    i;
 560         for(;base<KERNEL_STACKS_END;base+=KERNEL_STACK_SIZE)
 561         {
 562                 if(MM_GetPhysAddr(base) != 0)   continue;
 563                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 564                         MM_Allocate(base+i);
 565                 }
 566                 return base+KERNEL_STACK_SIZE;
 567         }
 568         Warning("MM_NewKStack - No address space left\n");
 569         return 0;
 570 }
 571
 572 /**
 573  * \fn Uint MM_NewWorkerStack()
 574  * \brief Creates a new worker stack
 575  */
 576 Uint MM_NewWorkerStack()
 577 {
 578         Uint    esp, ebp;
 579         Uint    oldstack;
 580         Uint    base, addr;
 581          int    i, j;
 582         Uint    *tmpPage;
 583         tPAddr  pages[WORKER_STACK_SIZE>>12];
 584
 585         // Get the old ESP and EBP
 586         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 587         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 588
 589         // Find a free worker stack address
 590         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 591         {
 592                 // Used block
 593                 if( gWorkerStacks[base/32] == -1 ) {
 594                         base += 31;     base &= ~31;
 595                         base --;        // Counteracted by the base++
 596                         continue;
 597                 }
 598                 // Used stack
 599                 if( gWorkerStacks[base/32] & (1 << base) ) {
 600                         continue;
 601                 }
 602         }
 603         if(base >= NUM_WORKER_STACKS) {
 604                 Warning("Uh-oh! Out of worker stacks");
 605                 return 0;
 606         }
 607
 608         // It's ours now!
 609         gWorkerStacks[base/32] |= (1 << base);
 610         // Make life easier for later calls
 611         giLastUsedWorker = base;
 612         // We have one
 613         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 614
 615         // Acquire the lock for the temp fractal mappings
 616         LOCK(&gilTempFractal);
 617
 618         // Set the temp fractals to TID0's address space
 619         *gTmpCR3 = (Uint)gaInitPageDir | 3;
 620         INVLPG( gaTmpDir );
 621
 622         // Check if the directory is mapped (we are assuming that the stacks
 623         // will fit neatly in a directory
 624         if(gaTmpDir[ base >> 22 ] == 0) {
 625                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 626                 INVLPG( &gaTmpTable[ (base>>22) & ~0x3FF ] );
 627         }
 628
 629         // Mapping Time!
 630         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 631         {
 632                 pages[ addr >> 12 ] = MM_AllocPhys();
 633                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 634         }
 635         // Release the temp mapping lock
 636         RELEASE(&gilTempFractal);
 637
 638         // Copy the old stack
 639         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 640         esp = oldstack - esp;   // ESP as an offset in the stack
 641
 642         i = (WORKER_STACK_SIZE>>12) - 1;
 643         // Copy the contents of the old stack to the new one, altering the addresses
 644         // `addr` is refering to bytes from the stack base (mem downwards)
 645         for(addr = 0; addr < esp; addr += 0x1000)
 646         {
 647                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 648                 tmpPage = (void*)MM_MapTemp( pages[i] );
 649                 // Copy old stack
 650                 for(j = 0; j < 1024; j++)
 651                 {
 652                         // Possible Stack address?
 653                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 654                                 tmpPage[j] = base - (oldstack - stack[j]);
 655                         else    // Seems not, best leave it alone
 656                                 tmpPage[j] = stack[j];
 657                 }
 658                 MM_FreeTemp((Uint)tmpPage);
 659                 i --;
 660         }
 661
 662         return base;
 663 }
 664
 665 /**
 666  * \fn void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 667  * \brief Sets the flags on a page
 668  */
 669 void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 670 {
 671         tPAddr  *ent;
 672         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 673         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 674
 675         ent = &gaPageTable[VAddr >> 12];
 676
 677         // Read-Only
 678         if( Mask & MM_PFLAG_RO )
 679         {
 680                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 681                 else    *ent |= PF_WRITE;
 682         }
 683
 684         // Kernel
 685         if( Mask & MM_PFLAG_KERNEL )
 686         {
 687                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 688                 else    *ent |= PF_USER;
 689         }
 690
 691         // Copy-On-Write
 692         if( Mask & MM_PFLAG_COW )
 693         {
 694                 if( Flags & MM_PFLAG_COW ) {
 695                         *ent &= ~PF_WRITE;
 696                         *ent |= PF_COW;
 697                 }
 698                 else {
 699                         *ent &= ~PF_COW;
 700                         *ent |= PF_WRITE;
 701                 }
 702         }
 703 }
 704
 705 /**
 706  * \fn tPAddr MM_DuplicatePage(Uint VAddr)
 707  * \brief Duplicates a virtual page to a physical one
 708  */
 709 tPAddr MM_DuplicatePage(Uint VAddr)
 710 {
 711         tPAddr  ret;
 712         Uint    temp;
 713          int    wasRO = 0;
 714
 715         // Check if mapped
 716         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 717         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 718
 719         // Page Align
 720         VAddr &= ~0xFFF;
 721
 722         // Allocate new page
 723         ret = MM_AllocPhys();
 724
 725         // Write-lock the page (to keep data constistent), saving its R/W state
 726         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 727         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 728         INVLPG( VAddr );
 729
 730         // Copy Data
 731         temp = MM_MapTemp(ret);
 732         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 733         MM_FreeTemp(temp);
 734
 735         // Restore Writeable status
 736         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 737         INVLPG(VAddr);
 738
 739         return ret;
 740 }
 741
 742 /**
 743  * \fn Uint MM_MapTemp(tPAddr PAddr)
 744  * \brief Create a temporary memory mapping
 745  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 746  */
 747 Uint MM_MapTemp(tPAddr PAddr)
 748 {
 749          int    i;
 750
 751         //ENTER("XPAddr", PAddr);
 752
 753         PAddr &= ~0xFFF;
 754
 755         //LOG("gilTempMappings = %i", gilTempMappings);
 756
 757         for(;;)
 758         {
 759                 LOCK( &gilTempMappings );
 760
 761                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 762                 {
 763                         // Check if page used
 764                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 765                         // Mark as used
 766                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 767                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 768                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 769                         RELEASE( &gilTempMappings );
 770                         return TEMP_MAP_ADDR + (i << 12);
 771                 }
 772                 RELEASE( &gilTempMappings );
 773                 Threads_Yield();
 774         }
 775 }
 776
 777 /**
 778  * \fn void MM_FreeTemp(Uint PAddr)
 779  * \brief Free's a temp mapping
 780  */
 781 void MM_FreeTemp(Uint VAddr)
 782 {
 783          int    i = VAddr >> 12;
 784         //ENTER("xVAddr", VAddr);
 785
 786         if(i >= (TEMP_MAP_ADDR >> 12))
 787                 gaPageTable[ i ] = 0;
 788
 789         //LEAVE('-');
 790 }
 791
 792 /**
 793  * \fn Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 794  * \brief Allocates a contigous number of pages
 795  */
 796 Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 797 {
 798          int    i, j;
 799
 800         PAddr &= ~0xFFF;
 801
 802         // Scan List
 803         for( i = 0; i < NUM_HW_PAGES; i ++ )
 804         {
 805                 // Check if addr used
 806                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 807                         continue;
 808
 809                 // Check possible region
 810                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 811                 {
 812                         // If there is an allocated page in the region we are testing, break
 813                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 814                 }
 815                 // Is it all free?
 816                 if( j == Number )
 817                 {
 818                         // Allocate
 819                         for( j = 0; j < Number; j++ ) {
 820                                 MM_RefPhys( PAddr + (j<<12) );
 821                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 822                         }
 823                         return HW_MAP_ADDR + (i<<12);
 824                 }
 825         }
 826         // If we don't find any, return NULL
 827         return 0;
 828 }
 829
 830 /**
 831  * \fn void MM_UnmapHWPage(Uint VAddr, Uint Number)
 832  * \brief Unmap a hardware page
 833  */
 834 void MM_UnmapHWPage(Uint VAddr, Uint Number)
 835 {
 836          int    i, j;
 837         // Sanity Check
 838         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 839
 840         i = VAddr >> 12;
 841
 842         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 843
 844         for( j = 0; j < Number; j++ )
 845         {
 846                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 847                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 848         }
 849
 850         RELEASE( &gilTempMappings );
 851 }
 852
 853 // --- EXPORTS ---
 854 EXPORT(MM_GetPhysAddr);
 855 EXPORT(MM_Map);
 856 //EXPORT(MM_Unmap);
 857 EXPORT(MM_MapHWPage);
 858 EXPORT(MM_UnmapHWPage);