KernelLand/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 #include <hal_proc.h>
  19 #include <arch_int.h>
  20
  21 #define TAB     22
  22
  23 #define WORKER_STACKS           0x00100000      // Thread0 Only!
  24 #define WORKER_STACK_SIZE       MM_KERNEL_STACK_SIZE
  25 #define WORKER_STACKS_END       0xB0000000
  26 #define NUM_WORKER_STACKS       ((WORKER_STACKS_END-WORKER_STACKS)/WORKER_STACK_SIZE)
  27
  28 #define PAE_PAGE_TABLE_ADDR     0xFC000000      // 16 MiB
  29 #define PAE_PAGE_DIR_ADDR       0xFCFC0000      // 16 KiB
  30 #define PAE_PAGE_PDPT_ADDR      0xFCFC3F00      // 32 bytes
  31 #define PAE_TMP_PDPT_ADDR       0xFCFC3F20      // 32 bytes
  32 #define PAE_TMP_DIR_ADDR        0xFCFE0000      // 16 KiB
  33 #define PAE_TMP_TABLE_ADDR      0xFD000000      // 16 MiB
  34
  35 #define PAGE_TABLE_ADDR 0xFC000000
  36 #define PAGE_DIR_ADDR   0xFC3F0000
  37 #define PAGE_CR3_ADDR   0xFC3F0FC0
  38 #define TMP_CR3_ADDR    0xFC3F0FC4      // Part of core instead of temp
  39 #define TMP_DIR_ADDR    0xFC3F1000      // Same
  40 #define TMP_TABLE_ADDR  0xFC400000
  41
  42 #define HW_MAP_ADDR             0xFE000000
  43 #define HW_MAP_MAX              0xFFEF0000
  44 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  45 #define TEMP_MAP_ADDR   0xFFEF0000      // Allows 16 "temp" pages
  46 #define NUM_TEMP_PAGES  16
  47 #define LAST_BLOCK_ADDR 0xFFFF0000      // Free space for kernel provided user code/ *(-1) protection
  48
  49 #define PF_PRESENT      0x1
  50 #define PF_WRITE        0x2
  51 #define PF_USER         0x4
  52 #define PF_GLOBAL       0x80
  53 #define PF_COW          0x200
  54 #define PF_NOPAGE       0x400
  55
  56 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  57
  58 #define GET_TEMP_MAPPING(cr3) do { \
  59         __ASM__("cli"); \
  60         __AtomicTestSetLoop( (Uint *)gpTmpCR3, cr3 | 3 ); \
  61 } while(0)
  62 #define REL_TEMP_MAPPING() do { \
  63         *gpTmpCR3 = 0; \
  64         __ASM__("sti"); \
  65 } while(0)
  66
  67 typedef Uint32  tTabEnt;
  68
  69 // === IMPORTS ===
  70 extern char     _UsertextEnd[], _UsertextBase[];
  71 extern Uint32   gaInitPageDir[1024];
  72 extern Uint32   gaInitPageTable[1024];
  73 extern void     Threads_SegFault(tVAddr Addr);
  74 extern void     Error_Backtrace(Uint eip, Uint ebp);
  75
  76 // === PROTOTYPES ===
  77 void    MM_PreinitVirtual(void);
  78 void    MM_InstallVirtual(void);
  79 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  80 //void  MM_DumpTables(tVAddr Start, tVAddr End);
  81 //void  MM_ClearUser(void);
  82 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  83
  84 // === GLOBALS ===
  85 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  86 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  87 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  88 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  89 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  90 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  91
  92 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  93 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  94 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  95 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  96 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  97 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  98  int    gbUsePAE = 0;
  99 tMutex  glTempMappings;
 100 tMutex  glTempFractal;
 101 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
 102  int    giLastUsedWorker = 0;
 103 struct sPageInfo {
 104         void    *Node;
 105         tVAddr  Base;
 106         Uint64  Offset;
 107          int    Length;
 108          int    Flags;
 109 }       *gaMappedRegions;       // sizeof = 24 bytes
 110
 111 // === CODE ===
 112 /**
 113  * \fn void MM_PreinitVirtual(void)
 114  * \brief Maps the fractal mappings
 115  */
 116 void MM_PreinitVirtual(void)
 117 {
 118         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 119         INVLPG( PAGE_TABLE_ADDR );
 120 }
 121
 122 /**
 123  * \fn void MM_InstallVirtual(void)
 124  * \brief Sets up the constant page mappings
 125  */
 126 void MM_InstallVirtual(void)
 127 {
 128          int    i;
 129
 130         // --- Pre-Allocate kernel tables
 131         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 132         {
 133                 if( gaPageDir[ i ] )    continue;
 134                 // Skip stack tables, they are process unique
 135                 if( i > MM_KERNEL_STACKS >> 22 && i < MM_KERNEL_STACKS_END >> 22) {
 136                         gaPageDir[ i ] = 0;
 137                         continue;
 138                 }
 139                 // Preallocate table
 140                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 141                 INVLPG( &gaPageTable[i*1024] );
 142                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 143         }
 144
 145         // Unset kernel on the User Text pages
 146         for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
 147                 MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
 148         }
 149
 150         *gpTmpCR3 = 0;
 151 }
 152
 153 /**
 154  * \brief Cleans up the SMP required mappings
 155  */
 156 void MM_FinishVirtualInit(void)
 157 {
 158         gaInitPageDir[ 0 ] = 0;
 159 }
 160
 161 /**
 162  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 163  * \brief Called on a page fault
 164  */
 165 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 166 {
 167         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 168
 169         // -- Check for COW --
 170         if( gaPageDir  [Addr>>22] & PF_PRESENT  && gaPageTable[Addr>>12] & PF_PRESENT
 171          && gaPageTable[Addr>>12] & PF_COW )
 172         {
 173                 tPAddr  paddr;
 174                 __asm__ __volatile__ ("sti");
 175                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 176                 {
 177                         gaPageTable[Addr>>12] &= ~PF_COW;
 178                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 179                 }
 180                 else
 181                 {
 182                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 183                         paddr = MM_DuplicatePage( Addr );
 184                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 185                         gaPageTable[Addr>>12] &= PF_USER;
 186                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 187                 }
 188
 189 //              Log_Debug("MMVirt", "COW for %p (%P)", Addr, gaPageTable[Addr>>12]);
 190
 191                 INVLPG( Addr & ~0xFFF );
 192                 return;
 193         }
 194
 195         // Disable instruction tracing
 196         __ASM__("pushf; andw $0xFEFF, 0(%esp); popf");
 197         Proc_GetCurThread()->bInstrTrace = 0;
 198
 199         // If it was a user, tell the thread handler
 200         if(ErrorCode & 4) {
 201                 __asm__ __volatile__ ("sti");
 202                 Log_Warning("MMVirt", "User %s %s memory%s",
 203                         (ErrorCode&2?"write to":"read from"),
 204                         (ErrorCode&1?"bad/locked":"non-present"),
 205                         (ErrorCode&16?" (Instruction Fetch)":"")
 206                         );
 207                 Log_Warning("MMVirt", "Instruction %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 208                 __ASM__("sti"); // Restart IRQs
 209                 #if 1
 210                 Error_Backtrace(Regs->eip, Regs->ebp);
 211                 #endif
 212                 Threads_SegFault(Addr);
 213                 return ;
 214         }
 215
 216         Debug_KernelPanic();
 217
 218         // -- Check Error Code --
 219         if(ErrorCode & 8)
 220                 Warning("Reserved Bits Trashed!");
 221         else
 222         {
 223                 Warning("Kernel %s %s memory%s",
 224                         (ErrorCode&2?"write to":"read from"),
 225                         (ErrorCode&1?"bad/locked":"non-present"),
 226                         (ErrorCode&16?" (Instruction Fetch)":"")
 227                         );
 228         }
 229
 230         Log("CPU %i - Code at %p accessed %p", GetCPUNum(), Regs->eip, Addr);
 231         // Print Stack Backtrace
 232         Error_Backtrace(Regs->eip, Regs->ebp);
 233
 234         #if 0
 235         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 236         if( gaPageDir[Addr>>22] & PF_PRESENT )
 237                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 238         #endif
 239         //MM_DumpTables(0, -1);
 240
 241         // Register Dump
 242         Log("EAX %08x ECX %08x EDX %08x EBX %08x", Regs->eax, Regs->ecx, Regs->edx, Regs->ebx);
 243         Log("ESP %08x EBP %08x ESI %08x EDI %08x", Regs->esp, Regs->ebp, Regs->esi, Regs->edi);
 244         //Log("SS:ESP %04x:%08x", Regs->ss, Regs->esp);
 245         Log("CS:EIP %04x:%08x", Regs->cs, Regs->eip);
 246         Log("DS %04x ES %04x FS %04x GS %04x", Regs->ds, Regs->es, Regs->fs, Regs->gs);
 247         {
 248                 Uint    dr0, dr1;
 249                 __ASM__ ("mov %%dr0, %0":"=r"(dr0):);
 250                 __ASM__ ("mov %%dr1, %0":"=r"(dr1):);
 251                 Log("DR0 %08x DR1 %08x", dr0, dr1);
 252         }
 253
 254         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 255 }
 256
 257 /**
 258  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 259  * \brief Dumps the layout of the page tables
 260  */
 261 void MM_DumpTables(tVAddr Start, tVAddr End)
 262 {
 263         tVAddr  rangeStart = 0;
 264         tPAddr  expected = 0;
 265         void    *expected_node = NULL, *tmpnode = NULL;
 266         tVAddr  curPos;
 267         Uint    page;
 268         const tPAddr    MASK = ~0xF78;
 269
 270         Start >>= 12;   End >>= 12;
 271
 272         #if 0
 273         Log("Directory Entries:");
 274         for(page = Start >> 10;
 275                 page < (End >> 10)+1;
 276                 page ++)
 277         {
 278                 if(gaPageDir[page])
 279                 {
 280                         Log(" 0x%08x-0x%08x :: 0x%08x",
 281                                 page<<22, ((page+1)<<22)-1,
 282                                 gaPageDir[page]&~0xFFF
 283                                 );
 284                 }
 285         }
 286         #endif
 287
 288         Log("Table Entries:");
 289         for(page = Start, curPos = Start<<12;
 290                 page < End;
 291                 curPos += 0x1000, page++)
 292         {
 293                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 294                 ||  !(gaPageTable[page] & PF_PRESENT)
 295                 ||  (gaPageTable[page] & MASK) != expected
 296                 ||  (tmpnode=NULL,MM_GetPageNode(expected, &tmpnode), tmpnode != expected_node))
 297                 {
 298                         if(expected) {
 299                                 tPAddr  orig = gaPageTable[rangeStart>>12];
 300                                 Log(" 0x%08x => 0x%08x - 0x%08x (%s%s%s%s%s) %p",
 301                                         rangeStart,
 302                                         orig & ~0xFFF,
 303                                         curPos - rangeStart,
 304                                         (orig & PF_NOPAGE ? "P" : "-"),
 305                                         (orig & PF_COW ? "C" : "-"),
 306                                         (orig & PF_GLOBAL ? "G" : "-"),
 307                                         (orig & PF_USER ? "U" : "-"),
 308                                         (orig & PF_WRITE ? "W" : "-"),
 309                                         expected_node
 310                                         );
 311                                 expected = 0;
 312                         }
 313                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 314                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 315
 316                         expected = (gaPageTable[page] & MASK);
 317                         MM_GetPageNode(expected, &expected_node);
 318                         rangeStart = curPos;
 319                 }
 320                 if(expected)    expected += 0x1000;
 321         }
 322
 323         if(expected) {
 324                 tPAddr  orig = gaPageTable[rangeStart>>12];
 325                 Log("0x%08x => 0x%08x - 0x%08x (%s%s%s%s%s) %p",
 326                         rangeStart,
 327                         orig & ~0xFFF,
 328                         curPos - rangeStart,
 329                         (orig & PF_NOPAGE ? "p" : "-"),
 330                         (orig & PF_COW ? "C" : "-"),
 331                         (orig & PF_GLOBAL ? "G" : "-"),
 332                         (orig & PF_USER ? "U" : "-"),
 333                         (orig & PF_WRITE ? "W" : "-"),
 334                         expected_node
 335                         );
 336                 expected = 0;
 337         }
 338 }
 339
 340 /**
 341  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 342  */
 343 tPAddr MM_Allocate(tVAddr VAddr)
 344 {
 345         tPAddr  paddr;
 346         //ENTER("xVAddr", VAddr);
 347         //__ASM__("xchg %bx,%bx");
 348         // Check if the directory is mapped
 349         if( gaPageDir[ VAddr >> 22 ] == 0 )
 350         {
 351                 // Allocate directory
 352                 paddr = MM_AllocPhys();
 353                 if( paddr == 0 ) {
 354                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 355                         //LEAVE('i',0);
 356                         return 0;
 357                 }
 358                 // Map and mark as user (if needed)
 359                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 360                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 361
 362                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 363                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 364         }
 365         // Check if the page is already allocated
 366         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 367                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 368                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 369                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 370         }
 371
 372         // Allocate
 373         paddr = MM_AllocPhys();
 374         //LOG("paddr = 0x%llx", paddr);
 375         if( paddr == 0 ) {
 376                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 377                         VAddr, __builtin_return_address(0));
 378                 //LEAVE('i',0);
 379                 return 0;
 380         }
 381         // Map
 382         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 383         // Mark as user
 384         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 385         // Invalidate Cache for address
 386         INVLPG( VAddr & ~0xFFF );
 387
 388         //LEAVE('X', paddr);
 389         return paddr;
 390 }
 391
 392 /**
 393  * \fn void MM_Deallocate(tVAddr VAddr)
 394  */
 395 void MM_Deallocate(tVAddr VAddr)
 396 {
 397         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 398                 Warning("MM_Deallocate - Directory not mapped");
 399                 return;
 400         }
 401
 402         if(gaPageTable[ VAddr >> 12 ] == 0) {
 403                 Warning("MM_Deallocate - Page is not allocated");
 404                 return;
 405         }
 406
 407         // Dereference page
 408         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 409         // Clear page
 410         gaPageTable[ VAddr >> 12 ] = 0;
 411 }
 412
 413 /**
 414  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 415  * \brief Checks if the passed address is accesable
 416  */
 417 tPAddr MM_GetPhysAddr(tVAddr Addr)
 418 {
 419         if( !(gaPageDir[Addr >> 22] & 1) )
 420                 return 0;
 421         if( !(gaPageTable[Addr >> 12] & 1) )
 422                 return 0;
 423         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 424 }
 425
 426 /**
 427  * \fn void MM_SetCR3(Uint CR3)
 428  * \brief Sets the current process space
 429  */
 430 void MM_SetCR3(Uint CR3)
 431 {
 432         __ASM__("mov %0, %%cr3"::"r"(CR3));
 433 }
 434
 435 /**
 436  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 437  * \brief Map a physical page to a virtual one
 438  */
 439 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 440 {
 441         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 442         // Sanity check
 443         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 444                 Log_Warning("MM_Virt", "MM_Map - Physical or Virtual Addresses are not aligned (0x%P and %p)",
 445                         PAddr, VAddr);
 446                 //LEAVE('i', 0);
 447                 return 0;
 448         }
 449
 450         // Align addresses
 451         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 452
 453         // Check if the directory is mapped
 454         if( gaPageDir[ VAddr >> 22 ] == 0 )
 455         {
 456                 tPAddr  tmp = MM_AllocPhys();
 457                 if( tmp == 0 )
 458                         return 0;
 459                 gaPageDir[ VAddr >> 22 ] = tmp | 3;
 460
 461                 // Mark as user
 462                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 463
 464                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 465                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 466         }
 467         // Check if the page is already allocated
 468         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 469                 Warning("MM_Map - Allocating to used address");
 470                 //LEAVE('i', 0);
 471                 return 0;
 472         }
 473
 474         // Map
 475         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 476         // Mark as user
 477         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 478
 479         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 480         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 481
 482         // Reference
 483         MM_RefPhys( PAddr );
 484
 485         //LOG("INVLPG( 0x%x )", VAddr);
 486         INVLPG( VAddr );
 487
 488         //LEAVE('i', 1);
 489         return 1;
 490 }
 491
 492 /**
 493  * \brief Clear user's address space
 494  */
 495 void MM_ClearUser(void)
 496 {
 497         Uint    i, j;
 498
 499         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 500         {
 501                 // Check if directory is not allocated
 502                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 503                         gaPageDir[i] = 0;
 504                         continue;
 505                 }
 506
 507                 // Deallocate tables
 508                 for( j = 0; j < 1024; j ++ )
 509                 {
 510                         if( gaPageTable[i*1024+j] & 1 )
 511                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 512                         gaPageTable[i*1024+j] = 0;
 513                 }
 514
 515                 // Deallocate directory
 516                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 517                 gaPageDir[i] = 0;
 518                 INVLPG( &gaPageTable[i*1024] );
 519         }
 520         INVLPG( gaPageDir );
 521 }
 522
 523 /**
 524  * \brief Deallocate an address space
 525  */
 526 void MM_ClearSpace(Uint32 CR3)
 527 {
 528          int    i, j;
 529
 530         if(CR3 == (*gpPageCR3 & ~0xFFF)) {
 531                 Log_Error("MMVirt", "Can't clear current address space");
 532                 return ;
 533         }
 534
 535         if( MM_GetRefCount(CR3) > 1 ) {
 536                 MM_DerefPhys(CR3);
 537                 Log_Log("MMVirt", "CR3 %P is still referenced, not cleaning (but dereferenced)", CR3);
 538                 return ;
 539         }
 540
 541         Log_Debug("MMVirt", "Clearing out address space 0x%x from 0x%x", CR3, *gpPageCR3);
 542
 543         GET_TEMP_MAPPING(CR3);
 544         INVLPG( gaTmpDir );
 545
 546         for( i = 0; i < 1024; i ++ )
 547         {
 548                 Uint32  *table = &gaTmpTable[i*1024];
 549                 if( !(gaTmpDir[i] & PF_PRESENT) )
 550                         continue ;
 551
 552                 INVLPG( table );
 553
 554                 if( i < 768 || (i > MM_KERNEL_STACKS >> 22 && i < MM_KERNEL_STACKS_END >> 22) )
 555                 {
 556                         for( j = 0; j < 1024; j ++ )
 557                         {
 558                                 if( !(table[j] & 1) )
 559                                         continue;
 560                                 MM_DerefPhys( table[j] & ~0xFFF );
 561                         }
 562                 }
 563
 564                 if( i != (PAGE_TABLE_ADDR >> 22) )
 565                 {
 566                         MM_DerefPhys( gaTmpDir[i] & ~0xFFF );
 567                 }
 568         }
 569
 570
 571         MM_DerefPhys( CR3 );
 572
 573         REL_TEMP_MAPPING();
 574 }
 575
 576 /**
 577  * \fn tPAddr MM_Clone(void)
 578  * \brief Clone the current address space
 579  */
 580 tPAddr MM_Clone(int bNoUserCopy)
 581 {
 582         Uint    i, j;
 583         tPAddr  ret;
 584         Uint    page = 0;
 585         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - MM_KERNEL_STACK_SIZE;
 586         void    *tmp;
 587
 588         // Create Directory Table
 589         ret = MM_AllocPhys();
 590         if( ret == 0 ) {
 591                 return 0;
 592         }
 593
 594         // Map
 595         GET_TEMP_MAPPING( ret );
 596         INVLPG( gaTmpDir );
 597         memsetd( gaTmpDir, 0, 1024 );
 598
 599         if( Threads_GetPID() != 0 && !bNoUserCopy )
 600         {
 601                 // Copy Tables
 602                 for( i = 0; i < 768; i ++)
 603                 {
 604                         // Check if table is allocated
 605                         if( !(gaPageDir[i] & PF_PRESENT) ) {
 606                                 gaTmpDir[i] = 0;
 607                                 page += 1024;
 608                                 continue;
 609                         }
 610
 611                         // Allocate new table
 612                         gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 613                         INVLPG( &gaTmpTable[page] );
 614                         // Fill
 615                         for( j = 0; j < 1024; j ++, page++ )
 616                         {
 617                                 if( !(gaPageTable[page] & PF_PRESENT) ) {
 618                                         gaTmpTable[page] = 0;
 619                                         continue;
 620                                 }
 621
 622                                 // Refrence old page
 623                                 MM_RefPhys( gaPageTable[page] & ~0xFFF );
 624                                 // Add to new table
 625                                 if(gaPageTable[page] & PF_WRITE) {
 626                                         gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 627                                         gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 628                                         INVLPG( page << 12 );
 629                                 }
 630                                 else
 631                                         gaTmpTable[page] = gaPageTable[page];
 632                         }
 633                 }
 634         }
 635
 636         // Map in kernel tables (and make fractal mapping)
 637         for( i = 768; i < 1024; i ++ )
 638         {
 639                 // Fractal
 640                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 641                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 642                         continue;
 643                 }
 644                 if( i == (TMP_TABLE_ADDR >> 22) ) {
 645                         gaTmpDir[ TMP_TABLE_ADDR >> 22 ] = 0;
 646                         continue ;
 647                 }
 648
 649                 if( gaPageDir[i] == 0 ) {
 650                         gaTmpDir[i] = 0;
 651                         continue;
 652                 }
 653
 654                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 655                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 656                 gaTmpDir[i] = gaPageDir[i];
 657         }
 658
 659         // Allocate kernel stack
 660         for(i = MM_KERNEL_STACKS >> 22; i < MM_KERNEL_STACKS_END >> 22; i ++ )
 661         {
 662                 // Check if directory is allocated
 663                 if( (gaPageDir[i] & 1) == 0 ) {
 664                         gaTmpDir[i] = 0;
 665                         continue;
 666                 }
 667
 668                 // We don't care about other kernel stacks, just the current one
 669                 if( i != kStackBase >> 22 ) {
 670                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 671                         gaTmpDir[i] = 0;
 672                         continue;
 673                 }
 674
 675                 // Create a copy
 676                 gaTmpDir[i] = MM_AllocPhys() | 3;
 677                 INVLPG( &gaTmpTable[i*1024] );
 678                 for( j = 0; j < 1024; j ++ )
 679                 {
 680                         // Is the page allocated? If not, skip
 681                         if( !(gaPageTable[i*1024+j] & 1) ) {
 682                                 gaTmpTable[i*1024+j] = 0;
 683                                 continue;
 684                         }
 685
 686                         // We don't care about other kernel stacks
 687                         if( ((i*1024+j)*4096 & ~(MM_KERNEL_STACK_SIZE-1)) != kStackBase ) {
 688                                 gaTmpTable[i*1024+j] = 0;
 689                                 continue;
 690                         }
 691
 692                         // Allocate page
 693                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 694
 695                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 696
 697                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 698                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 699                         MM_FreeTemp( (Uint)tmp );
 700                 }
 701         }
 702
 703         REL_TEMP_MAPPING();
 704
 705         //LEAVE('x', ret);
 706         return ret;
 707 }
 708
 709 /**
 710  * \fn tVAddr MM_NewKStack(void)
 711  * \brief Create a new kernel stack
 712  */
 713 tVAddr MM_NewKStack(void)
 714 {
 715         tVAddr  base;
 716         Uint    i;
 717         for(base = MM_KERNEL_STACKS; base < MM_KERNEL_STACKS_END; base += MM_KERNEL_STACK_SIZE)
 718         {
 719                 // Check if space is free
 720                 if(MM_GetPhysAddr(base) != 0)   continue;
 721                 // Allocate
 722                 //for(i = MM_KERNEL_STACK_SIZE; i -= 0x1000 ; )
 723                 for(i = 0; i < MM_KERNEL_STACK_SIZE; i += 0x1000 )
 724                 {
 725                         if( MM_Allocate(base+i) == 0 )
 726                         {
 727                                 // On error, print a warning and return error
 728                                 Warning("MM_NewKStack - Out of memory");
 729                                 // - Clean up
 730                                 //for( i += 0x1000 ; i < MM_KERNEL_STACK_SIZE; i += 0x1000 )
 731                                 //      MM_Deallocate(base+i);
 732                                 return 0;
 733                         }
 734                 }
 735                 // Success
 736 //              Log("MM_NewKStack - Allocated %p", base + MM_KERNEL_STACK_SIZE);
 737                 return base+MM_KERNEL_STACK_SIZE;
 738         }
 739         // No stacks left
 740         Log_Warning("MMVirt", "MM_NewKStack - No address space left");
 741         return 0;
 742 }
 743
 744 /**
 745  * \fn tVAddr MM_NewWorkerStack()
 746  * \brief Creates a new worker stack
 747  */
 748 tVAddr MM_NewWorkerStack(Uint *StackContents, size_t ContentsSize)
 749 {
 750         Uint    base, addr;
 751         tVAddr  tmpPage;
 752         tPAddr  page;
 753
 754         // TODO: Thread safety
 755         // Find a free worker stack address
 756         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 757         {
 758                 // Used block
 759                 if( gWorkerStacks[base/32] == -1 ) {
 760                         base += 31;     base &= ~31;
 761                         base --;        // Counteracted by the base++
 762                         continue;
 763                 }
 764                 // Used stack
 765                 if( gWorkerStacks[base/32] & (1 << base) ) {
 766                         continue;
 767                 }
 768                 break;
 769         }
 770         if(base >= NUM_WORKER_STACKS) {
 771                 Warning("Uh-oh! Out of worker stacks");
 772                 return 0;
 773         }
 774
 775         // It's ours now!
 776         gWorkerStacks[base/32] |= (1 << base);
 777         // Make life easier for later calls
 778         giLastUsedWorker = base;
 779         // We have one
 780         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 781         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 782
 783         // Set the temp fractals to TID0's address space
 784         GET_TEMP_MAPPING( ((Uint)gaInitPageDir - KERNEL_BASE) );
 785         INVLPG( gaTmpDir );
 786
 787         // Check if the directory is mapped (we are assuming that the stacks
 788         // will fit neatly in a directory)
 789         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 790         if(gaTmpDir[ base >> 22 ] == 0) {
 791                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 792                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 793         }
 794
 795         // Mapping Time!
 796         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 797         {
 798                 page = MM_AllocPhys();
 799                 gaTmpTable[ (base + addr) >> 12 ] = page | 3;
 800         }
 801
 802         // Release temporary fractal
 803         REL_TEMP_MAPPING();
 804
 805         // NOTE: Max of 1 page
 806         // `page` is the last allocated page from the previious for loop
 807         tmpPage = MM_MapTemp( page );
 808         memcpy( (void*)( tmpPage + (0x1000 - ContentsSize) ), StackContents, ContentsSize);
 809         MM_FreeTemp(tmpPage);
 810
 811         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 812         return base + WORKER_STACK_SIZE;
 813 }
 814
 815 /**
 816  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 817  * \brief Sets the flags on a page
 818  */
 819 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 820 {
 821         tTabEnt *ent;
 822         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 823         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 824
 825         ent = &gaPageTable[VAddr >> 12];
 826
 827         // Read-Only
 828         if( Mask & MM_PFLAG_RO )
 829         {
 830                 if( Flags & MM_PFLAG_RO ) {
 831                         *ent &= ~PF_WRITE;
 832                 }
 833                 else {
 834                         gaPageDir[VAddr >> 22] |= PF_WRITE;
 835                         *ent |= PF_WRITE;
 836                 }
 837         }
 838
 839         // Kernel
 840         if( Mask & MM_PFLAG_KERNEL )
 841         {
 842                 if( Flags & MM_PFLAG_KERNEL ) {
 843                         *ent &= ~PF_USER;
 844                 }
 845                 else {
 846                         gaPageDir[VAddr >> 22] |= PF_USER;
 847                         *ent |= PF_USER;
 848                 }
 849         }
 850
 851         // Copy-On-Write
 852         if( Mask & MM_PFLAG_COW )
 853         {
 854                 if( Flags & MM_PFLAG_COW ) {
 855                         *ent &= ~PF_WRITE;
 856                         *ent |= PF_COW;
 857                 }
 858                 else {
 859                         *ent &= ~PF_COW;
 860                         *ent |= PF_WRITE;
 861                 }
 862         }
 863
 864         //Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
 865         //      *ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 866 }
 867
 868 /**
 869  * \brief Get the flags on a page
 870  */
 871 Uint MM_GetFlags(tVAddr VAddr)
 872 {
 873         tTabEnt *ent;
 874         Uint    ret = 0;
 875
 876         // Validity Check
 877         if( !(gaPageDir[VAddr >> 22] & 1) )     return 0;
 878         if( !(gaPageTable[VAddr >> 12] & 1) )   return 0;
 879
 880         ent = &gaPageTable[VAddr >> 12];
 881
 882         // Read-Only
 883         if( !(*ent & PF_WRITE) )        ret |= MM_PFLAG_RO;
 884         // Kernel
 885         if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
 886         // Copy-On-Write
 887         if( *ent & PF_COW )     ret |= MM_PFLAG_COW;
 888
 889         return ret;
 890 }
 891
 892 /**
 893  * \brief Check if the provided buffer is valid
 894  * \return Boolean valid
 895  */
 896 int MM_IsValidBuffer(tVAddr Addr, size_t Size)
 897 {
 898          int    bIsUser;
 899          int    dir, tab;
 900
 901         Size += Addr & (PAGE_SIZE-1);
 902         Addr &= ~(PAGE_SIZE-1);
 903
 904         dir = Addr >> 22;
 905         tab = Addr >> 12;
 906
 907 //      Debug("Addr = %p, Size = 0x%x, dir = %i, tab = %i", Addr, Size, dir, tab);
 908
 909         if( !(gaPageDir[dir] & 1) )     return 0;
 910         if( !(gaPageTable[tab] & 1) )   return 0;
 911
 912         bIsUser = !!(gaPageTable[tab] & PF_USER);
 913
 914         while( Size >= PAGE_SIZE )
 915         {
 916                 if( (tab & 1023) == 0 )
 917                 {
 918                         dir ++;
 919                         if( !(gaPageDir[dir] & 1) )     return 0;
 920                 }
 921
 922                 if( !(gaPageTable[tab] & 1) )   return 0;
 923                 if( bIsUser && !(gaPageTable[tab] & PF_USER) )  return 0;
 924
 925                 tab ++;
 926                 Size -= PAGE_SIZE;
 927         }
 928         return 1;
 929 }
 930
 931 /**
 932  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 933  * \brief Duplicates a virtual page to a physical one
 934  */
 935 tPAddr MM_DuplicatePage(tVAddr VAddr)
 936 {
 937         tPAddr  ret;
 938         Uint    temp;
 939          int    wasRO = 0;
 940
 941         //ENTER("xVAddr", VAddr);
 942
 943         // Check if mapped
 944         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 945         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 946
 947         // Page Align
 948         VAddr &= ~0xFFF;
 949
 950         // Allocate new page
 951         ret = MM_AllocPhys();
 952         if( !ret ) {
 953                 return 0;
 954         }
 955
 956         // Write-lock the page (to keep data constistent), saving its R/W state
 957         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 958         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 959         INVLPG( VAddr );
 960
 961         // Copy Data
 962         temp = MM_MapTemp(ret);
 963         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 964         MM_FreeTemp(temp);
 965
 966         // Restore Writeable status
 967         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 968         INVLPG(VAddr);
 969
 970         //LEAVE('X', ret);
 971         return ret;
 972 }
 973
 974 /**
 975  * \fn Uint MM_MapTemp(tPAddr PAddr)
 976  * \brief Create a temporary memory mapping
 977  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 978  */
 979 tVAddr MM_MapTemp(tPAddr PAddr)
 980 {
 981          int    i;
 982
 983         //ENTER("XPAddr", PAddr);
 984
 985         PAddr &= ~0xFFF;
 986
 987         //LOG("glTempMappings = %i", glTempMappings);
 988
 989         for(;;)
 990         {
 991                 Mutex_Acquire( &glTempMappings );
 992
 993                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 994                 {
 995                         // Check if page used
 996                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 997                         // Mark as used
 998                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 999                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
1000                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
1001                         Mutex_Release( &glTempMappings );
1002                         return TEMP_MAP_ADDR + (i << 12);
1003                 }
1004                 Mutex_Release( &glTempMappings );
1005                 Threads_Yield();        // TODO: Use a sleep queue here instead
1006         }
1007 }
1008
1009 /**
1010  * \fn void MM_FreeTemp(tVAddr PAddr)
1011  * \brief Free's a temp mapping
1012  */
1013 void MM_FreeTemp(tVAddr VAddr)
1014 {
1015          int    i = VAddr >> 12;
1016         //ENTER("xVAddr", VAddr);
1017
1018         if(i >= (TEMP_MAP_ADDR >> 12))
1019                 gaPageTable[ i ] = 0;
1020
1021         //LEAVE('-');
1022 }
1023
1024 /**
1025  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
1026  * \brief Allocates a contigous number of pages
1027  */
1028 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
1029 {
1030          int    i, j;
1031
1032         PAddr &= ~0xFFF;
1033
1034         // Scan List
1035         for( i = 0; i < NUM_HW_PAGES; i ++ )
1036         {
1037                 // Check if addr used
1038                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
1039                         continue;
1040
1041                 // Check possible region
1042                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
1043                 {
1044                         // If there is an allocated page in the region we are testing, break
1045                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
1046                 }
1047                 // Is it all free?
1048                 if( j == Number )
1049                 {
1050                         // Allocate
1051                         for( j = 0; j < Number; j++ ) {
1052                                 MM_RefPhys( PAddr + (j<<12) );
1053                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
1054                         }
1055                         return HW_MAP_ADDR + (i<<12);
1056                 }
1057         }
1058         // If we don't find any, return NULL
1059         return 0;
1060 }
1061
1062 /**
1063  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
1064  * \brief Allocates DMA physical memory
1065  * \param Pages Number of pages required
1066  * \param MaxBits       Maximum number of bits the physical address can have
1067  * \param PhysAddr      Pointer to the location to place the physical address allocated
1068  * \return Virtual address allocate
1069  */
1070 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
1071 {
1072         tPAddr  maxCheck = (1 << MaxBits);
1073         tPAddr  phys;
1074         tVAddr  ret;
1075
1076         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
1077
1078         // Sanity Check
1079         if(MaxBits < 12 || !PhysAddr) {
1080                 LEAVE('i', 0);
1081                 return 0;
1082         }
1083
1084         // Bound
1085         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
1086
1087         // Fast Allocate
1088         if(Pages == 1 && MaxBits >= PHYS_BITS)
1089         {
1090                 phys = MM_AllocPhys();
1091                 if( !phys ) {
1092                         *PhysAddr = 0;
1093                         LEAVE_RET('i', 0);
1094                 }
1095                 *PhysAddr = phys;
1096                 ret = MM_MapHWPages(phys, 1);
1097                 if(ret == 0) {
1098                         MM_DerefPhys(phys);
1099                         LEAVE('i', 0);
1100                         return 0;
1101                 }
1102                 LEAVE('x', ret);
1103                 return ret;
1104         }
1105
1106         // Slow Allocate
1107         phys = MM_AllocPhysRange(Pages, MaxBits);
1108         // - Was it allocated?
1109         if(phys == 0) {
1110                 LEAVE('i', 0);
1111                 return 0;
1112         }
1113
1114         // Allocated successfully, now map
1115         ret = MM_MapHWPages(phys, Pages);
1116         if( ret == 0 ) {
1117                 // If it didn't map, free then return 0
1118                 for(;Pages--;phys+=0x1000)
1119                         MM_DerefPhys(phys);
1120                 LEAVE('i', 0);
1121                 return 0;
1122         }
1123
1124         *PhysAddr = phys;
1125         LEAVE('x', ret);
1126         return ret;
1127 }
1128
1129 /**
1130  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1131  * \brief Unmap a hardware page
1132  */
1133 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1134 {
1135          int    i, j;
1136
1137         //Log_Debug("VirtMem", "MM_UnmapHWPages: (VAddr=0x%08x, Number=%i)", VAddr, Number);
1138
1139         // Sanity Check
1140         if(VAddr < HW_MAP_ADDR || VAddr+Number*0x1000 > HW_MAP_MAX)     return;
1141
1142         i = VAddr >> 12;
1143
1144         Mutex_Acquire( &glTempMappings );       // Temp and HW share a directory, so they share a lock
1145
1146         for( j = 0; j < Number; j++ )
1147         {
1148                 MM_DerefPhys( gaPageTable[ i + j ] & ~0xFFF );
1149                 gaPageTable[ i + j ] = 0;
1150         }
1151
1152         Mutex_Release( &glTempMappings );
1153 }
1154