Kernel/arch/x86/mm_virt.c

   1 /*
   2  * AcessOS Microkernel Version
   3  * mm_virt.c
   4  *
   5  * Memory Map
   6  * 0xE0 - Kernel Base
   7  * 0xF0 - Kernel Stacks
   8  * 0xFD - Fractals
   9  * 0xFE - Unused
  10  * 0xFF - System Calls / Kernel's User Code
  11  */
  12 #define DEBUG   0
  13 #define SANITY  1
  14 #include <acess.h>
  15 #include <mm_virt.h>
  16 #include <mm_phys.h>
  17 #include <proc.h>
  18
  19 #define TAB     22
  20
  21 #define KERNEL_STACKS           0xF0000000
  22 #define KERNEL_STACK_SIZE       0x00008000
  23 #define KERNEL_STACKS_END       0xFC000000
  24 #define WORKER_STACKS           0x00100000      // Thread0 Only!
  25 #define WORKER_STACK_SIZE       KERNEL_STACK_SIZE
  26 #define WORKER_STACKS_END       0xB0000000
  27 #define NUM_WORKER_STACKS       ((WORKER_STACKS_END-WORKER_STACKS)/WORKER_STACK_SIZE)
  28
  29 #define PAE_PAGE_TABLE_ADDR     0xFC000000      // 16 MiB
  30 #define PAE_PAGE_DIR_ADDR       0xFCFC0000      // 16 KiB
  31 #define PAE_PAGE_PDPT_ADDR      0xFCFC3F00      // 32 bytes
  32 #define PAE_TMP_PDPT_ADDR       0xFCFC3F20      // 32 bytes
  33 #define PAE_TMP_DIR_ADDR        0xFCFE0000      // 16 KiB
  34 #define PAE_TMP_TABLE_ADDR      0xFD000000      // 16 MiB
  35
  36 #define PAGE_TABLE_ADDR 0xFC000000
  37 #define PAGE_DIR_ADDR   0xFC3F0000
  38 #define PAGE_CR3_ADDR   0xFC3F0FC0
  39 #define TMP_CR3_ADDR    0xFC3F0FC4      // Part of core instead of temp
  40 #define TMP_DIR_ADDR    0xFC3F1000      // Same
  41 #define TMP_TABLE_ADDR  0xFC400000
  42
  43 #define HW_MAP_ADDR             0xFE000000
  44 #define HW_MAP_MAX              0xFFEF0000
  45 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  46 #define TEMP_MAP_ADDR   0xFFEF0000      // Allows 16 "temp" pages
  47 #define NUM_TEMP_PAGES  16
  48 #define LAST_BLOCK_ADDR 0xFFFF0000      // Free space for kernel provided user code/ *(-1) protection
  49
  50 #define PF_PRESENT      0x1
  51 #define PF_WRITE        0x2
  52 #define PF_USER         0x4
  53 #define PF_GLOBAL       0x80
  54 #define PF_COW          0x200
  55 #define PF_NOPAGE       0x400
  56
  57 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  58
  59 typedef Uint32  tTabEnt;
  60
  61 // === IMPORTS ===
  62 extern void     _UsertextEnd, _UsertextBase;
  63 extern Uint32   gaInitPageDir[1024];
  64 extern Uint32   gaInitPageTable[1024];
  65 extern void     Threads_SegFault(tVAddr Addr);
  66 extern void     Error_Backtrace(Uint eip, Uint ebp);
  67
  68 // === PROTOTYPES ===
  69 void    MM_PreinitVirtual(void);
  70 void    MM_InstallVirtual(void);
  71 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  72 void    MM_DumpTables(tVAddr Start, tVAddr End);
  73 tVAddr  MM_ClearUser(void);
  74 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  75
  76 // === GLOBALS ===
  77 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  78 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  79 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  80 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  81 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  82 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  83
  84 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  85 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  86 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  87 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  88 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  89 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  90  int    gbUsePAE = 0;
  91 tMutex  glTempMappings;
  92 tMutex  glTempFractal;
  93 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
  94  int    giLastUsedWorker = 0;
  95 struct sPageInfo {
  96         void    *Node;
  97         tVAddr  Base;
  98         Uint64  Offset;
  99          int    Length;
 100          int    Flags;
 101 }       *gaMappedRegions;       // sizeof = 24 bytes
 102
 103 // === CODE ===
 104 /**
 105  * \fn void MM_PreinitVirtual(void)
 106  * \brief Maps the fractal mappings
 107  */
 108 void MM_PreinitVirtual(void)
 109 {
 110         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 111         INVLPG( PAGE_TABLE_ADDR );
 112 }
 113
 114 /**
 115  * \fn void MM_InstallVirtual(void)
 116  * \brief Sets up the constant page mappings
 117  */
 118 void MM_InstallVirtual(void)
 119 {
 120          int    i;
 121
 122         // --- Pre-Allocate kernel tables
 123         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 124         {
 125                 if( gaPageDir[ i ] )    continue;
 126                 // Skip stack tables, they are process unique
 127                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 128                         gaPageDir[ i ] = 0;
 129                         continue;
 130                 }
 131                 // Preallocate table
 132                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 133                 INVLPG( &gaPageTable[i*1024] );
 134                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 135         }
 136
 137         // Unset kernel on the User Text pages
 138         for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
 139                 MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
 140         }
 141 }
 142
 143 /**
 144  * \brief Cleans up the SMP required mappings
 145  */
 146 void MM_FinishVirtualInit(void)
 147 {
 148         gaInitPageDir[ 0 ] = 0;
 149 }
 150
 151 /**
 152  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 153  * \brief Called on a page fault
 154  */
 155 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 156 {
 157         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 158
 159         // -- Check for COW --
 160         if( gaPageDir  [Addr>>22] & PF_PRESENT  && gaPageTable[Addr>>12] & PF_PRESENT
 161          && gaPageTable[Addr>>12] & PF_COW )
 162         {
 163                 tPAddr  paddr;
 164                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 165                 {
 166                         gaPageTable[Addr>>12] &= ~PF_COW;
 167                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 168                 }
 169                 else
 170                 {
 171                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 172                         paddr = MM_DuplicatePage( Addr );
 173                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 174                         gaPageTable[Addr>>12] &= PF_USER;
 175                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 176                 }
 177
 178                 Log_Debug("MMVirt", "COW for %p", Addr);
 179
 180                 INVLPG( Addr & ~0xFFF );
 181                 return;
 182         }
 183
 184         // If it was a user, tell the thread handler
 185         if(ErrorCode & 4) {
 186                 Log_Warning("MMVirt", "%s %s %s memory%s",
 187                         (ErrorCode&4?"User":"Kernel"),
 188                         (ErrorCode&2?"write to":"read from"),
 189                         (ErrorCode&1?"bad/locked":"non-present"),
 190                         (ErrorCode&16?" (Instruction Fetch)":"")
 191                         );
 192                 Warning("User Pagefault: Instruction at %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 193                 __asm__ __volatile__ ("sti");   // Restart IRQs
 194                 #if 1
 195                 Error_Backtrace(Regs->eip, Regs->ebp);
 196                 #endif
 197                 Threads_SegFault(Addr);
 198                 return ;
 199         }
 200
 201         Debug_KernelPanic();
 202
 203         // -- Check Error Code --
 204         if(ErrorCode & 8)
 205                 Warning("Reserved Bits Trashed!");
 206         else
 207         {
 208                 Warning("%s %s %s memory%s",
 209                         (ErrorCode&4?"User":"Kernel"),
 210                         (ErrorCode&2?"write to":"read from"),
 211                         (ErrorCode&1?"bad/locked":"non-present"),
 212                         (ErrorCode&16?" (Instruction Fetch)":"")
 213                         );
 214         }
 215
 216         Log("Code at %p accessed %p", Regs->eip, Addr);
 217         // Print Stack Backtrace
 218         Error_Backtrace(Regs->eip, Regs->ebp);
 219
 220         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 221         if( gaPageDir[Addr>>22] & PF_PRESENT )
 222                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 223
 224         //MM_DumpTables(0, -1);
 225
 226         // Register Dump
 227         Log("EAX %08x ECX %08x EDX %08x EBX %08x", Regs->eax, Regs->ecx, Regs->edx, Regs->ebx);
 228         Log("ESP %08x EBP %08x ESI %08x EDI %08x", Regs->esp, Regs->ebp, Regs->esi, Regs->edi);
 229         //Log("SS:ESP %04x:%08x", Regs->ss, Regs->esp);
 230         Log("CS:EIP %04x:%08x", Regs->cs, Regs->eip);
 231         Log("DS %04x ES %04x FS %04x GS %04x", Regs->ds, Regs->es, Regs->fs, Regs->gs);
 232         {
 233                 Uint    dr0, dr1;
 234                 __ASM__ ("mov %%dr0, %0":"=r"(dr0):);
 235                 __ASM__ ("mov %%dr1, %0":"=r"(dr1):);
 236                 Log("DR0 %08x DR1 %08x", dr0, dr1);
 237         }
 238
 239         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 240 }
 241
 242 /**
 243  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 244  * \brief Dumps the layout of the page tables
 245  */
 246 void MM_DumpTables(tVAddr Start, tVAddr End)
 247 {
 248         tVAddr  rangeStart = 0;
 249         tPAddr  expected = 0;
 250         tVAddr  curPos;
 251         Uint    page;
 252         const tPAddr    MASK = ~0xF78;
 253
 254         Start >>= 12;   End >>= 12;
 255
 256         #if 0
 257         Log("Directory Entries:");
 258         for(page = Start >> 10;
 259                 page < (End >> 10)+1;
 260                 page ++)
 261         {
 262                 if(gaPageDir[page])
 263                 {
 264                         Log(" 0x%08x-0x%08x :: 0x%08x",
 265                                 page<<22, ((page+1)<<22)-1,
 266                                 gaPageDir[page]&~0xFFF
 267                                 );
 268                 }
 269         }
 270         #endif
 271
 272         Log("Table Entries:");
 273         for(page = Start, curPos = Start<<12;
 274                 page < End;
 275                 curPos += 0x1000, page++)
 276         {
 277                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 278                 ||  !(gaPageTable[page] & PF_PRESENT)
 279                 ||  (gaPageTable[page] & MASK) != expected)
 280                 {
 281                         if(expected) {
 282                                 tPAddr  orig = gaPageTable[rangeStart>>12];
 283                                 Log(" 0x%08x => 0x%08x - 0x%08x (%s%s%s%s%s)",
 284                                         rangeStart,
 285                                         orig & ~0xFFF,
 286                                         curPos - rangeStart,
 287                                         (orig & PF_NOPAGE ? "P" : "-"),
 288                                         (orig & PF_COW ? "C" : "-"),
 289                                         (orig & PF_GLOBAL ? "G" : "-"),
 290                                         (orig & PF_USER ? "U" : "-"),
 291                                         (orig & PF_WRITE ? "W" : "-")
 292                                         );
 293                                 expected = 0;
 294                         }
 295                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 296                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 297
 298                         expected = (gaPageTable[page] & MASK);
 299                         rangeStart = curPos;
 300                 }
 301                 if(expected)    expected += 0x1000;
 302         }
 303
 304         if(expected) {
 305                 Log("0x%08x => 0x%08x - 0x%08x (%s%s%s%s)",
 306                         rangeStart,
 307                         gaPageTable[rangeStart>>12] & ~0xFFF,
 308                         curPos - rangeStart,
 309                         (expected & PF_NOPAGE ? "p" : "-"),
 310                         (expected & PF_COW ? "C" : "-"),
 311                         (expected & PF_USER ? "U" : "-"),
 312                         (expected & PF_WRITE ? "W" : "-")
 313                         );
 314                 expected = 0;
 315         }
 316 }
 317
 318 /**
 319  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 320  */
 321 tPAddr MM_Allocate(tVAddr VAddr)
 322 {
 323         tPAddr  paddr;
 324         //ENTER("xVAddr", VAddr);
 325         //__asm__ __volatile__ ("xchg %bx,%bx");
 326         // Check if the directory is mapped
 327         if( gaPageDir[ VAddr >> 22 ] == 0 )
 328         {
 329                 // Allocate directory
 330                 paddr = MM_AllocPhys();
 331                 if( paddr == 0 ) {
 332                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 333                         //LEAVE('i',0);
 334                         return 0;
 335                 }
 336                 // Map and mark as user (if needed)
 337                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 338                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 339
 340                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 341                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 342         }
 343         // Check if the page is already allocated
 344         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 345                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 346                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 347                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 348         }
 349
 350         // Allocate
 351         paddr = MM_AllocPhys();
 352         //LOG("paddr = 0x%llx", paddr);
 353         if( paddr == 0 ) {
 354                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 355                         VAddr, __builtin_return_address(0));
 356                 //LEAVE('i',0);
 357                 return 0;
 358         }
 359         // Map
 360         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 361         // Mark as user
 362         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 363         // Invalidate Cache for address
 364         INVLPG( VAddr & ~0xFFF );
 365
 366         //LEAVE('X', paddr);
 367         return paddr;
 368 }
 369
 370 /**
 371  * \fn void MM_Deallocate(tVAddr VAddr)
 372  */
 373 void MM_Deallocate(tVAddr VAddr)
 374 {
 375         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 376                 Warning("MM_Deallocate - Directory not mapped");
 377                 return;
 378         }
 379
 380         if(gaPageTable[ VAddr >> 12 ] == 0) {
 381                 Warning("MM_Deallocate - Page is not allocated");
 382                 return;
 383         }
 384
 385         // Dereference page
 386         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 387         // Clear page
 388         gaPageTable[ VAddr >> 12 ] = 0;
 389 }
 390
 391 /**
 392  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 393  * \brief Checks if the passed address is accesable
 394  */
 395 tPAddr MM_GetPhysAddr(tVAddr Addr)
 396 {
 397         if( !(gaPageDir[Addr >> 22] & 1) )
 398                 return 0;
 399         if( !(gaPageTable[Addr >> 12] & 1) )
 400                 return 0;
 401         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 402 }
 403
 404 /**
 405  * \fn void MM_SetCR3(Uint CR3)
 406  * \brief Sets the current process space
 407  */
 408 void MM_SetCR3(Uint CR3)
 409 {
 410         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 411 }
 412
 413 /**
 414  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 415  * \brief Map a physical page to a virtual one
 416  */
 417 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 418 {
 419         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 420         // Sanity check
 421         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 422                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 423                 //LEAVE('i', 0);
 424                 return 0;
 425         }
 426
 427         // Align addresses
 428         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 429
 430         // Check if the directory is mapped
 431         if( gaPageDir[ VAddr >> 22 ] == 0 )
 432         {
 433                 tPAddr  tmp = MM_AllocPhys();
 434                 if( tmp == 0 )
 435                         return 0;
 436                 gaPageDir[ VAddr >> 22 ] = tmp | 3;
 437
 438                 // Mark as user
 439                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 440
 441                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 442                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 443         }
 444         // Check if the page is already allocated
 445         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 446                 Warning("MM_Map - Allocating to used address");
 447                 //LEAVE('i', 0);
 448                 return 0;
 449         }
 450
 451         // Map
 452         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 453         // Mark as user
 454         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 455
 456         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 457         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 458
 459         // Reference
 460         MM_RefPhys( PAddr );
 461
 462         //LOG("INVLPG( 0x%x )", VAddr);
 463         INVLPG( VAddr );
 464
 465         //LEAVE('i', 1);
 466         return 1;
 467 }
 468
 469 /**
 470  * \fn tVAddr MM_ClearUser()
 471  * \brief Clear user's address space
 472  */
 473 tVAddr MM_ClearUser(void)
 474 {
 475         Uint    i, j;
 476
 477         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 478         {
 479                 // Check if directory is not allocated
 480                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 481                         gaPageDir[i] = 0;
 482                         continue;
 483                 }
 484
 485                 // Deallocate tables
 486                 for( j = 0; j < 1024; j ++ )
 487                 {
 488                         if( gaPageTable[i*1024+j] & 1 )
 489                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 490                         gaPageTable[i*1024+j] = 0;
 491                 }
 492
 493                 // Deallocate directory
 494                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 495                 gaPageDir[i] = 0;
 496                 INVLPG( &gaPageTable[i*1024] );
 497         }
 498         INVLPG( gaPageDir );
 499
 500         return *gpPageCR3;
 501 }
 502
 503 /**
 504  * \fn tPAddr MM_Clone(void)
 505  * \brief Clone the current address space
 506  */
 507 tPAddr MM_Clone(void)
 508 {
 509         Uint    i, j;
 510         tVAddr  ret;
 511         Uint    page = 0;
 512         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 513         void    *tmp;
 514
 515         Mutex_Acquire( &glTempFractal );
 516
 517         // Create Directory Table
 518         *gpTmpCR3 = MM_AllocPhys() | 3;
 519         if( *gpTmpCR3 == 3 ) {
 520                 *gpTmpCR3 = 0;
 521                 return 0;
 522         }
 523         INVLPG( gaTmpDir );
 524         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 525         memsetd( gaTmpDir, 0, 1024 );
 526
 527         if( Threads_GetPID() != 0 )
 528         {
 529                 // Copy Tables
 530                 for( i = 0; i < 768; i ++)
 531                 {
 532                         // Check if table is allocated
 533                         if( !(gaPageDir[i] & PF_PRESENT) ) {
 534                                 gaTmpDir[i] = 0;
 535                                 page += 1024;
 536                                 continue;
 537                         }
 538
 539                         // Allocate new table
 540                         gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 541                         INVLPG( &gaTmpTable[page] );
 542                         // Fill
 543                         for( j = 0; j < 1024; j ++, page++ )
 544                         {
 545                                 if( !(gaPageTable[page] & PF_PRESENT) ) {
 546                                         gaTmpTable[page] = 0;
 547                                         continue;
 548                                 }
 549
 550                                 // Refrence old page
 551                                 MM_RefPhys( gaPageTable[page] & ~0xFFF );
 552                                 // Add to new table
 553                                 if(gaPageTable[page] & PF_WRITE) {
 554                                         gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 555                                         gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 556                                         INVLPG( page << 12 );
 557                                 }
 558                                 else
 559                                         gaTmpTable[page] = gaPageTable[page];
 560                         }
 561                 }
 562         }
 563
 564         // Map in kernel tables (and make fractal mapping)
 565         for( i = 768; i < 1024; i ++ )
 566         {
 567                 // Fractal
 568                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 569                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 570                         continue;
 571                 }
 572
 573                 if( gaPageDir[i] == 0 ) {
 574                         gaTmpDir[i] = 0;
 575                         continue;
 576                 }
 577
 578                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 579                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 580                 gaTmpDir[i] = gaPageDir[i];
 581         }
 582
 583         // Allocate kernel stack
 584         for(i = KERNEL_STACKS >> 22;
 585                 i < KERNEL_STACKS_END >> 22;
 586                 i ++ )
 587         {
 588                 // Check if directory is allocated
 589                 if( (gaPageDir[i] & 1) == 0 ) {
 590                         gaTmpDir[i] = 0;
 591                         continue;
 592                 }
 593
 594                 // We don't care about other kernel stacks, just the current one
 595                 if( i != kStackBase >> 22 ) {
 596                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 597                         gaTmpDir[i] = 0;
 598                         continue;
 599                 }
 600
 601                 // Create a copy
 602                 gaTmpDir[i] = MM_AllocPhys() | 3;
 603                 INVLPG( &gaTmpTable[i*1024] );
 604                 for( j = 0; j < 1024; j ++ )
 605                 {
 606                         // Is the page allocated? If not, skip
 607                         if( !(gaPageTable[i*1024+j] & 1) ) {
 608                                 gaTmpTable[i*1024+j] = 0;
 609                                 continue;
 610                         }
 611
 612                         // We don't care about other kernel stacks
 613                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 614                                 gaTmpTable[i*1024+j] = 0;
 615                                 continue;
 616                         }
 617
 618                         // Allocate page
 619                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 620
 621                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 622
 623                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 624                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 625                         MM_FreeTemp( (Uint)tmp );
 626                 }
 627         }
 628
 629         ret = *gpTmpCR3 & ~0xFFF;
 630         Mutex_Release( &glTempFractal );
 631
 632         //LEAVE('x', ret);
 633         return ret;
 634 }
 635
 636 /**
 637  * \fn tVAddr MM_NewKStack(void)
 638  * \brief Create a new kernel stack
 639  */
 640 tVAddr MM_NewKStack(void)
 641 {
 642         tVAddr  base;
 643         Uint    i;
 644         for(base = KERNEL_STACKS; base < KERNEL_STACKS_END; base += KERNEL_STACK_SIZE)
 645         {
 646                 // Check if space is free
 647                 if(MM_GetPhysAddr(base) != 0)   continue;
 648                 // Allocate
 649                 //for(i = KERNEL_STACK_SIZE; i -= 0x1000 ; )
 650                 for(i = 0; i < KERNEL_STACK_SIZE; i += 0x1000 )
 651                 {
 652                         if( MM_Allocate(base+i) == 0 )
 653                         {
 654                                 // On error, print a warning and return error
 655                                 Warning("MM_NewKStack - Out of memory");
 656                                 // - Clean up
 657                                 //for( i += 0x1000 ; i < KERNEL_STACK_SIZE; i += 0x1000 )
 658                                 //      MM_Deallocate(base+i);
 659                                 return 0;
 660                         }
 661                 }
 662                 // Success
 663                 Log("MM_NewKStack - Allocated %p", base + KERNEL_STACK_SIZE);
 664                 return base+KERNEL_STACK_SIZE;
 665         }
 666         // No stacks left
 667         Warning("MM_NewKStack - No address space left");
 668         return 0;
 669 }
 670
 671 /**
 672  * \fn tVAddr MM_NewWorkerStack()
 673  * \brief Creates a new worker stack
 674  */
 675 tVAddr MM_NewWorkerStack()
 676 {
 677         Uint    esp, ebp;
 678         Uint    oldstack;
 679         Uint    base, addr;
 680          int    i, j;
 681         Uint    *tmpPage;
 682         tPAddr  pages[WORKER_STACK_SIZE>>12];
 683
 684         // Get the old ESP and EBP
 685         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 686         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 687
 688         // TODO: Thread safety
 689         // Find a free worker stack address
 690         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 691         {
 692                 // Used block
 693                 if( gWorkerStacks[base/32] == -1 ) {
 694                         base += 31;     base &= ~31;
 695                         base --;        // Counteracted by the base++
 696                         continue;
 697                 }
 698                 // Used stack
 699                 if( gWorkerStacks[base/32] & (1 << base) ) {
 700                         continue;
 701                 }
 702                 break;
 703         }
 704         if(base >= NUM_WORKER_STACKS) {
 705                 Warning("Uh-oh! Out of worker stacks");
 706                 return 0;
 707         }
 708
 709         // It's ours now!
 710         gWorkerStacks[base/32] |= (1 << base);
 711         // Make life easier for later calls
 712         giLastUsedWorker = base;
 713         // We have one
 714         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 715         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 716
 717         // Acquire the lock for the temp fractal mappings
 718         Mutex_Acquire(&glTempFractal);
 719
 720         // Set the temp fractals to TID0's address space
 721         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 722         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 723         INVLPG( gaTmpDir );
 724
 725
 726         // Check if the directory is mapped (we are assuming that the stacks
 727         // will fit neatly in a directory)
 728         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 729         if(gaTmpDir[ base >> 22 ] == 0) {
 730                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 731                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 732         }
 733
 734         // Mapping Time!
 735         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 736         //for( addr = WORKER_STACK_SIZE; addr; 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         Mutex_Release(&glTempFractal);
 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  * \brief Get the flags on a page
 831  */
 832 Uint MM_GetFlags(tVAddr VAddr)
 833 {
 834         tTabEnt *ent;
 835         Uint    ret = 0;
 836
 837         // Validity Check
 838         if( !(gaPageDir[VAddr >> 22] & 1) )     return 0;
 839         if( !(gaPageTable[VAddr >> 12] & 1) )   return 0;
 840
 841         ent = &gaPageTable[VAddr >> 12];
 842
 843         // Read-Only
 844         if( !(*ent & PF_WRITE) )        ret |= MM_PFLAG_RO;
 845         // Kernel
 846         if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
 847         // Copy-On-Write
 848         if( *ent & PF_COW )     ret |= MM_PFLAG_COW;
 849
 850         return ret;
 851 }
 852
 853 /**
 854  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 855  * \brief Duplicates a virtual page to a physical one
 856  */
 857 tPAddr MM_DuplicatePage(tVAddr VAddr)
 858 {
 859         tPAddr  ret;
 860         Uint    temp;
 861          int    wasRO = 0;
 862
 863         //ENTER("xVAddr", VAddr);
 864
 865         // Check if mapped
 866         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 867         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 868
 869         // Page Align
 870         VAddr &= ~0xFFF;
 871
 872         // Allocate new page
 873         ret = MM_AllocPhys();
 874         if( !ret ) {
 875                 return 0;
 876         }
 877
 878         // Write-lock the page (to keep data constistent), saving its R/W state
 879         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 880         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 881         INVLPG( VAddr );
 882
 883         // Copy Data
 884         temp = MM_MapTemp(ret);
 885         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 886         MM_FreeTemp(temp);
 887
 888         // Restore Writeable status
 889         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 890         INVLPG(VAddr);
 891
 892         //LEAVE('X', ret);
 893         return ret;
 894 }
 895
 896 /**
 897  * \fn Uint MM_MapTemp(tPAddr PAddr)
 898  * \brief Create a temporary memory mapping
 899  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 900  */
 901 tVAddr MM_MapTemp(tPAddr PAddr)
 902 {
 903          int    i;
 904
 905         //ENTER("XPAddr", PAddr);
 906
 907         PAddr &= ~0xFFF;
 908
 909         //LOG("glTempMappings = %i", glTempMappings);
 910
 911         for(;;)
 912         {
 913                 Mutex_Acquire( &glTempMappings );
 914
 915                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 916                 {
 917                         // Check if page used
 918                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 919                         // Mark as used
 920                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 921                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 922                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 923                         Mutex_Release( &glTempMappings );
 924                         return TEMP_MAP_ADDR + (i << 12);
 925                 }
 926                 Mutex_Release( &glTempMappings );
 927                 Threads_Yield();        // TODO: Use a sleep queue here instead
 928         }
 929 }
 930
 931 /**
 932  * \fn void MM_FreeTemp(tVAddr PAddr)
 933  * \brief Free's a temp mapping
 934  */
 935 void MM_FreeTemp(tVAddr VAddr)
 936 {
 937          int    i = VAddr >> 12;
 938         //ENTER("xVAddr", VAddr);
 939
 940         if(i >= (TEMP_MAP_ADDR >> 12))
 941                 gaPageTable[ i ] = 0;
 942
 943         //LEAVE('-');
 944 }
 945
 946 /**
 947  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 948  * \brief Allocates a contigous number of pages
 949  */
 950 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 951 {
 952          int    i, j;
 953
 954         PAddr &= ~0xFFF;
 955
 956         // Scan List
 957         for( i = 0; i < NUM_HW_PAGES; i ++ )
 958         {
 959                 // Check if addr used
 960                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 961                         continue;
 962
 963                 // Check possible region
 964                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 965                 {
 966                         // If there is an allocated page in the region we are testing, break
 967                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 968                 }
 969                 // Is it all free?
 970                 if( j == Number )
 971                 {
 972                         // Allocate
 973                         for( j = 0; j < Number; j++ ) {
 974                                 MM_RefPhys( PAddr + (j<<12) );
 975                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 976                         }
 977                         return HW_MAP_ADDR + (i<<12);
 978                 }
 979         }
 980         // If we don't find any, return NULL
 981         return 0;
 982 }
 983
 984 /**
 985  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 986  * \brief Allocates DMA physical memory
 987  * \param Pages Number of pages required
 988  * \param MaxBits       Maximum number of bits the physical address can have
 989  * \param PhysAddr      Pointer to the location to place the physical address allocated
 990  * \return Virtual address allocate
 991  */
 992 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 993 {
 994         tPAddr  maxCheck = (1 << MaxBits);
 995         tPAddr  phys;
 996         tVAddr  ret;
 997
 998         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
 999
1000         // Sanity Check
1001         if(MaxBits < 12 || !PhysAddr) {
1002                 LEAVE('i', 0);
1003                 return 0;
1004         }
1005
1006         // Bound
1007         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
1008
1009         // Fast Allocate
1010         if(Pages == 1 && MaxBits >= PHYS_BITS)
1011         {
1012                 phys = MM_AllocPhys();
1013                 if( !phys ) {
1014                         *PhysAddr = 0;
1015                         LEAVE_RET('i', 0);
1016                 }
1017                 *PhysAddr = phys;
1018                 ret = MM_MapHWPages(phys, 1);
1019                 if(ret == 0) {
1020                         MM_DerefPhys(phys);
1021                         LEAVE('i', 0);
1022                         return 0;
1023                 }
1024                 LEAVE('x', ret);
1025                 return ret;
1026         }
1027
1028         // Slow Allocate
1029         phys = MM_AllocPhysRange(Pages, MaxBits);
1030         // - Was it allocated?
1031         if(phys == 0) {
1032                 LEAVE('i', 0);
1033                 return 0;
1034         }
1035
1036         // Allocated successfully, now map
1037         ret = MM_MapHWPages(phys, Pages);
1038         if( ret == 0 ) {
1039                 // If it didn't map, free then return 0
1040                 for(;Pages--;phys+=0x1000)
1041                         MM_DerefPhys(phys);
1042                 LEAVE('i', 0);
1043                 return 0;
1044         }
1045
1046         *PhysAddr = phys;
1047         LEAVE('x', ret);
1048         return ret;
1049 }
1050
1051 /**
1052  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1053  * \brief Unmap a hardware page
1054  */
1055 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1056 {
1057          int    i, j;
1058
1059         //Log_Debug("VirtMem", "MM_UnmapHWPages: (VAddr=0x%08x, Number=%i)", VAddr, Number);
1060
1061         // Sanity Check
1062         if(VAddr < HW_MAP_ADDR || VAddr+Number*0x1000 > HW_MAP_MAX)     return;
1063
1064         i = VAddr >> 12;
1065
1066         Mutex_Acquire( &glTempMappings );       // Temp and HW share a directory, so they share a lock
1067
1068         for( j = 0; j < Number; j++ )
1069         {
1070                 MM_DerefPhys( gaPageTable[ i + j ] & ~0xFFF );
1071                 gaPageTable[ i + j ] = 0;
1072         }
1073
1074         Mutex_Release( &glTempMappings );
1075 }
1076