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 #if USE_PAE
  20 # define TAB    21
  21 # define DIR    30
  22 #else
  23 # define TAB    22
  24 #endif
  25
  26 #define KERNEL_STACKS           0xF0000000
  27 #define KERNEL_STACK_SIZE       0x00008000
  28 #define KERNEL_STACKS_END       0xFC000000
  29 #define WORKER_STACKS           0x00100000      // Thread0 Only!
  30 #define WORKER_STACK_SIZE       KERNEL_STACK_SIZE
  31 #define WORKER_STACKS_END       0xB0000000
  32 #define NUM_WORKER_STACKS       ((WORKER_STACKS_END-WORKER_STACKS)/WORKER_STACK_SIZE)
  33
  34 #define PAE_PAGE_TABLE_ADDR     0xFC000000      // 16 MiB
  35 #define PAE_PAGE_DIR_ADDR       0xFCFC0000      // 16 KiB
  36 #define PAE_PAGE_PDPT_ADDR      0xFCFC3F00      // 32 bytes
  37 #define PAE_TMP_PDPT_ADDR       0xFCFC3F20      // 32 bytes
  38 #define PAE_TMP_DIR_ADDR        0xFCFE0000      // 16 KiB
  39 #define PAE_TMP_TABLE_ADDR      0xFD000000      // 16 MiB
  40
  41 #define PAGE_TABLE_ADDR 0xFC000000
  42 #define PAGE_DIR_ADDR   0xFC3F0000
  43 #define PAGE_CR3_ADDR   0xFC3F0FC0
  44 #define TMP_CR3_ADDR    0xFC3F0FC4      // Part of core instead of temp
  45 #define TMP_DIR_ADDR    0xFC3F1000      // Same
  46 #define TMP_TABLE_ADDR  0xFC400000
  47
  48 #define HW_MAP_ADDR             0xFE000000
  49 #define HW_MAP_MAX              0xFFEF0000
  50 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  51 #define TEMP_MAP_ADDR   0xFFEF0000      // Allows 16 "temp" pages
  52 #define NUM_TEMP_PAGES  16
  53 #define LAST_BLOCK_ADDR 0xFFFF0000      // Free space for kernel provided user code/ *(-1) protection
  54
  55 #define PF_PRESENT      0x1
  56 #define PF_WRITE        0x2
  57 #define PF_USER         0x4
  58 #define PF_COW          0x200
  59 #define PF_PAGED        0x400
  60
  61 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  62
  63 #if USE_PAE
  64 typedef Uint64  tTabEnt;
  65 #else
  66 typedef Uint32  tTabEnt;
  67 #endif
  68
  69 // === IMPORTS ===
  70 extern void     _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();
  78 void    MM_InstallVirtual();
  79 void    MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
  80 void    MM_DumpTables(tVAddr Start, tVAddr End);
  81 tPAddr  MM_DuplicatePage(tVAddr VAddr);
  82
  83 // === GLOBALS ===
  84 #define gaPageTable     ((tTabEnt*)PAGE_TABLE_ADDR)
  85 #define gaPageDir       ((tTabEnt*)PAGE_DIR_ADDR)
  86 #define gaTmpTable      ((tTabEnt*)TMP_TABLE_ADDR)
  87 #define gaTmpDir        ((tTabEnt*)TMP_DIR_ADDR)
  88 #define gpPageCR3       ((tTabEnt*)PAGE_CR3_ADDR)
  89 #define gpTmpCR3        ((tTabEnt*)TMP_CR3_ADDR)
  90
  91 #define gaPAE_PageTable ((tTabEnt*)PAE_PAGE_TABLE_ADDR)
  92 #define gaPAE_PageDir   ((tTabEnt*)PAE_PAGE_DIR_ADDR)
  93 #define gaPAE_MainPDPT  ((tTabEnt*)PAE_PAGE_PDPT_ADDR)
  94 #define gaPAE_TmpTable  ((tTabEnt*)PAE_TMP_DIR_ADDR)
  95 #define gaPAE_TmpDir    ((tTabEnt*)PAE_TMP_DIR_ADDR)
  96 #define gaPAE_TmpPDPT   ((tTabEnt*)PAE_TMP_PDPT_ADDR)
  97  int    gbUsePAE = 0;
  98  int    gilTempMappings = 0;
  99  int    gilTempFractal = 0;
 100 Uint32  gWorkerStacks[(NUM_WORKER_STACKS+31)/32];
 101  int    giLastUsedWorker = 0;
 102
 103 // === CODE ===
 104 /**
 105  * \fn void MM_PreinitVirtual()
 106  * \brief Maps the fractal mappings
 107  */
 108 void MM_PreinitVirtual()
 109 {
 110         #if USE_PAE
 111         gaInitPageDir[ ((PAGE_TABLE_ADDR >> TAB)-3*512+3)*2 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 112         #else
 113         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((tTabEnt)&gaInitPageDir - KERNEL_BASE) | 3;
 114         #endif
 115         INVLPG( PAGE_TABLE_ADDR );
 116 }
 117
 118 /**
 119  * \fn void MM_InstallVirtual()
 120  * \brief Sets up the constant page mappings
 121  */
 122 void MM_InstallVirtual()
 123 {
 124          int    i;
 125
 126         #if USE_PAE
 127         // --- Pre-Allocate kernel tables
 128         for( i = KERNEL_BASE >> TAB; i < 1024*4; i ++ )
 129         {
 130                 if( gaPAE_PageDir[ i ] )        continue;
 131
 132                 // Skip stack tables, they are process unique
 133                 if( i > KERNEL_STACKS >> TAB && i < KERNEL_STACKS_END >> TAB) {
 134                         gaPAE_PageDir[ i ] = 0;
 135                         continue;
 136                 }
 137                 // Preallocate table
 138                 gaPAE_PageDir[ i ] = MM_AllocPhys() | 3;
 139                 INVLPG( &gaPAE_PageTable[i*512] );
 140                 memset( &gaPAE_PageTable[i*512], 0, 0x1000 );
 141         }
 142         #else
 143         // --- Pre-Allocate kernel tables
 144         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
 145         {
 146                 if( gaPageDir[ i ] )    continue;
 147                 // Skip stack tables, they are process unique
 148                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACKS_END >> 22) {
 149                         gaPageDir[ i ] = 0;
 150                         continue;
 151                 }
 152                 // Preallocate table
 153                 gaPageDir[ i ] = MM_AllocPhys() | 3;
 154                 INVLPG( &gaPageTable[i*1024] );
 155                 memset( &gaPageTable[i*1024], 0, 0x1000 );
 156         }
 157         #endif
 158
 159         // Unset kernel on the User Text pages
 160         for( i = ((tVAddr)&_UsertextEnd-(tVAddr)&_UsertextBase+0xFFF)/4096; i--; ) {
 161                 Log("MM_SetFlags( 0x%08x, 0, MM_PFLAG_KERNEL)", (tVAddr)&_UsertextBase + i*4096);
 162                 MM_SetFlags( (tVAddr)&_UsertextBase + i*4096, 0, MM_PFLAG_KERNEL );
 163         }
 164 }
 165
 166 /**
 167  * \brief Cleans up the SMP required mappings
 168  */
 169 void MM_FinishVirtualInit()
 170 {
 171         #if USE_PAE
 172         gaInitPDPT[ 0 ] = 0;
 173         #else
 174         gaInitPageDir[ 0 ] = 0;
 175         #endif
 176 }
 177
 178 /**
 179  * \fn void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 180  * \brief Called on a page fault
 181  */
 182 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 183 {
 184         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 185
 186         // -- Check for COW --
 187         if( gaPageDir  [Addr>>22] & PF_PRESENT
 188          && gaPageTable[Addr>>12] & PF_PRESENT
 189          && gaPageTable[Addr>>12] & PF_COW )
 190         {
 191                 tPAddr  paddr;
 192                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 193                 {
 194                         gaPageTable[Addr>>12] &= ~PF_COW;
 195                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 196                 }
 197                 else
 198                 {
 199                         //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
 200                         paddr = MM_DuplicatePage( Addr );
 201                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 202                         gaPageTable[Addr>>12] &= PF_USER;
 203                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 204                 }
 205
 206                 INVLPG( Addr & ~0xFFF );
 207                 //LEAVE('-')
 208                 return;
 209         }
 210
 211         // If it was a user, tell the thread handler
 212         if(ErrorCode & 4) {
 213                 Warning("%s %s %s memory%s",
 214                         (ErrorCode&4?"User":"Kernel"),
 215                         (ErrorCode&2?"write to":"read from"),
 216                         (ErrorCode&1?"bad/locked":"non-present"),
 217                         (ErrorCode&16?" (Instruction Fetch)":"")
 218                         );
 219                 Warning("User Pagefault: Instruction at %04x:%08x accessed %p", Regs->cs, Regs->eip, Addr);
 220                 __asm__ __volatile__ ("sti");   // Restart IRQs
 221                 Threads_SegFault(Addr);
 222                 return ;
 223         }
 224
 225         Debug_KernelPanic();
 226
 227         // -- Check Error Code --
 228         if(ErrorCode & 8)
 229                 Warning("Reserved Bits Trashed!");
 230         else
 231         {
 232                 Warning("%s %s %s memory%s",
 233                         (ErrorCode&4?"User":"Kernel"),
 234                         (ErrorCode&2?"write to":"read from"),
 235                         (ErrorCode&1?"bad/locked":"non-present"),
 236                         (ErrorCode&16?" (Instruction Fetch)":"")
 237                         );
 238         }
 239
 240         Log("Code at %p accessed %p", Regs->eip, Addr);
 241         // Print Stack Backtrace
 242         Error_Backtrace(Regs->eip, Regs->ebp);
 243
 244         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 245         if( gaPageDir[Addr>>22] & PF_PRESENT )
 246                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 247
 248         //MM_DumpTables(0, -1);
 249
 250         Panic("Page Fault at 0x%x (Accessed 0x%x)", Regs->eip, Addr);
 251 }
 252
 253 /**
 254  * \fn void MM_DumpTables(tVAddr Start, tVAddr End)
 255  * \brief Dumps the layout of the page tables
 256  */
 257 void MM_DumpTables(tVAddr Start, tVAddr End)
 258 {
 259         tVAddr  rangeStart = 0;
 260         tPAddr  expected = 0;
 261         tVAddr  curPos;
 262         Uint    page;
 263         const tPAddr    MASK = ~0xF98;
 264
 265         Start >>= 12;   End >>= 12;
 266
 267         #if 0
 268         Log("Directory Entries:");
 269         for(page = Start >> 10;
 270                 page < (End >> 10)+1;
 271                 page ++)
 272         {
 273                 if(gaPageDir[page])
 274                 {
 275                         Log(" 0x%08x-0x%08x :: 0x%08x",
 276                                 page<<22, ((page+1)<<22)-1,
 277                                 gaPageDir[page]&~0xFFF
 278                                 );
 279                 }
 280         }
 281         #endif
 282
 283         Log("Table Entries:");
 284         for(page = Start, curPos = Start<<12;
 285                 page < End;
 286                 curPos += 0x1000, page++)
 287         {
 288                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 289                 ||  !(gaPageTable[page] & PF_PRESENT)
 290                 ||  (gaPageTable[page] & MASK) != expected)
 291                 {
 292                         if(expected) {
 293                                 Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 294                                         rangeStart, curPos - 1,
 295                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 296                                         (expected & ~0xFFF) - 1,
 297                                         (expected & PF_PAGED ? "p" : "-"),
 298                                         (expected & PF_COW ? "C" : "-"),
 299                                         (expected & PF_USER ? "U" : "-"),
 300                                         (expected & PF_WRITE ? "W" : "-")
 301                                         );
 302                                 expected = 0;
 303                         }
 304                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 305                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 306
 307                         expected = (gaPageTable[page] & MASK);
 308                         rangeStart = curPos;
 309                 }
 310                 if(expected)    expected += 0x1000;
 311         }
 312
 313         if(expected) {
 314                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 315                         rangeStart, curPos - 1,
 316                         gaPageTable[rangeStart>>12] & ~0xFFF,
 317                         (expected & ~0xFFF) - 1,
 318                         (expected & PF_PAGED ? "p" : "-"),
 319                         (expected & PF_COW ? "C" : "-"),
 320                         (expected & PF_USER ? "U" : "-"),
 321                         (expected & PF_WRITE ? "W" : "-")
 322                         );
 323                 expected = 0;
 324         }
 325 }
 326
 327 /**
 328  * \fn tPAddr MM_Allocate(tVAddr VAddr)
 329  */
 330 tPAddr MM_Allocate(tVAddr VAddr)
 331 {
 332         tPAddr  paddr;
 333         //ENTER("xVAddr", VAddr);
 334         //__asm__ __volatile__ ("xchg %bx,%bx");
 335         // Check if the directory is mapped
 336         if( gaPageDir[ VAddr >> 22 ] == 0 )
 337         {
 338                 // Allocate directory
 339                 paddr = MM_AllocPhys();
 340                 //LOG("paddr = 0x%llx (new table)", paddr);
 341                 if( paddr == 0 ) {
 342                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 343                         //LEAVE('i',0);
 344                         return 0;
 345                 }
 346                 // Map
 347                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 348                 // Mark as user
 349                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 350
 351                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 352                 //LOG("Clearing new table");
 353                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 354         }
 355         // Check if the page is already allocated
 356         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 357                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 358                 //LEAVE('X', gaPageTable[ VAddr >> 12 ] & ~0xFFF);
 359                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 360         }
 361
 362         // Allocate
 363         paddr = MM_AllocPhys();
 364         //LOG("paddr = 0x%llx", paddr);
 365         if( paddr == 0 ) {
 366                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 367                         VAddr, __builtin_return_address(0));
 368                 //LEAVE('i',0);
 369                 return 0;
 370         }
 371         // Map
 372         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 373         // Mark as user
 374         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 375         // Invalidate Cache for address
 376         INVLPG( VAddr & ~0xFFF );
 377
 378         //LEAVE('X', paddr);
 379         return paddr;
 380 }
 381
 382 /**
 383  * \fn void MM_Deallocate(tVAddr VAddr)
 384  */
 385 void MM_Deallocate(tVAddr VAddr)
 386 {
 387         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 388                 Warning("MM_Deallocate - Directory not mapped");
 389                 return;
 390         }
 391
 392         if(gaPageTable[ VAddr >> 12 ] == 0) {
 393                 Warning("MM_Deallocate - Page is not allocated");
 394                 return;
 395         }
 396
 397         // Dereference page
 398         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 399         // Clear page
 400         gaPageTable[ VAddr >> 12 ] = 0;
 401 }
 402
 403 /**
 404  * \fn tPAddr MM_GetPhysAddr(tVAddr Addr)
 405  * \brief Checks if the passed address is accesable
 406  */
 407 tPAddr MM_GetPhysAddr(tVAddr Addr)
 408 {
 409         if( !(gaPageDir[Addr >> 22] & 1) )
 410                 return 0;
 411         if( !(gaPageTable[Addr >> 12] & 1) )
 412                 return 0;
 413         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 414 }
 415
 416
 417 /**
 418  * \fn int MM_IsUser(tVAddr VAddr)
 419  * \brief Checks if a page is user accessable
 420  */
 421 int MM_IsUser(tVAddr VAddr)
 422 {
 423         if( !(gaPageDir[VAddr >> 22] & 1) )
 424                 return 0;
 425         if( !(gaPageTable[VAddr >> 12] & 1) )
 426                 return 0;
 427         if( !(gaPageTable[VAddr >> 12] & PF_USER) )
 428                 return 0;
 429         return 1;
 430 }
 431
 432 /**
 433  * \fn void MM_SetCR3(Uint CR3)
 434  * \brief Sets the current process space
 435  */
 436 void MM_SetCR3(Uint CR3)
 437 {
 438         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 439 }
 440
 441 /**
 442  * \fn int MM_Map(tVAddr VAddr, tPAddr PAddr)
 443  * \brief Map a physical page to a virtual one
 444  */
 445 int MM_Map(tVAddr VAddr, tPAddr PAddr)
 446 {
 447         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 448         // Sanity check
 449         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 450                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 451                 //LEAVE('i', 0);
 452                 return 0;
 453         }
 454
 455         // Align addresses
 456         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 457
 458         // Check if the directory is mapped
 459         if( gaPageDir[ VAddr >> 22 ] == 0 )
 460         {
 461                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 462
 463                 // Mark as user
 464                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 465
 466                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 467                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 468         }
 469         // Check if the page is already allocated
 470         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 471                 Warning("MM_Map - Allocating to used address");
 472                 //LEAVE('i', 0);
 473                 return 0;
 474         }
 475
 476         // Map
 477         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 478         // Mark as user
 479         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 480
 481         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 482         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 483
 484         // Reference
 485         MM_RefPhys( PAddr );
 486
 487         //LOG("INVLPG( 0x%x )", VAddr);
 488         INVLPG( VAddr );
 489
 490         //LEAVE('i', 1);
 491         return 1;
 492 }
 493
 494 /**
 495  * \fn tVAddr MM_ClearUser()
 496  * \brief Clear user's address space
 497  */
 498 tVAddr MM_ClearUser()
 499 {
 500         Uint    i, j;
 501
 502         // Copy Directories
 503         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 504         {
 505                 // Check if directory is not allocated
 506                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 507                         gaPageDir[i] = 0;
 508                         continue;
 509                 }
 510
 511
 512                 for( j = 0; j < 1024; j ++ )
 513                 {
 514                         if( gaPageTable[i*1024+j] & 1 )
 515                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 516                         gaPageTable[i*1024+j] = 0;
 517                 }
 518
 519                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 520                 gaPageDir[i] = 0;
 521                 INVLPG( &gaPageTable[i*1024] );
 522         }
 523         INVLPG( gaPageDir );
 524
 525         return *gpPageCR3;
 526 }
 527
 528 /**
 529  * \fn tPAddr MM_Clone()
 530  * \brief Clone the current address space
 531  */
 532 tPAddr MM_Clone()
 533 {
 534         Uint    i, j;
 535         tVAddr  ret;
 536         Uint    page = 0;
 537         tVAddr  kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 538         void    *tmp;
 539
 540         LOCK( &gilTempFractal );
 541
 542         // Create Directory Table
 543         *gpTmpCR3 = MM_AllocPhys() | 3;
 544         INVLPG( gaTmpDir );
 545         //LOG("Allocated Directory (%x)", *gpTmpCR3);
 546         memsetd( gaTmpDir, 0, 1024 );
 547
 548         // Copy Tables
 549         for( i = 0; i < 768; i ++)
 550         {
 551                 // Check if table is allocated
 552                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 553                         gaTmpDir[i] = 0;
 554                         page += 1024;
 555                         continue;
 556                 }
 557
 558                 // Allocate new table
 559                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 560                 INVLPG( &gaTmpTable[page] );
 561                 // Fill
 562                 for( j = 0; j < 1024; j ++, page++ )
 563                 {
 564                         if( !(gaPageTable[page] & PF_PRESENT) ) {
 565                                 gaTmpTable[page] = 0;
 566                                 continue;
 567                         }
 568
 569                         // Refrence old page
 570                         MM_RefPhys( gaPageTable[page] & ~0xFFF );
 571                         // Add to new table
 572                         if(gaPageTable[page] & PF_WRITE) {
 573                                 gaTmpTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 574                                 gaPageTable[page] = (gaPageTable[page] & ~PF_WRITE) | PF_COW;
 575                                 INVLPG( page << 12 );
 576                         }
 577                         else
 578                                 gaTmpTable[page] = gaPageTable[page];
 579                 }
 580         }
 581
 582         // Map in kernel tables (and make fractal mapping)
 583         for( i = 768; i < 1024; i ++ )
 584         {
 585                 // Fractal
 586                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 587                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gpTmpCR3;
 588                         continue;
 589                 }
 590
 591                 if( gaPageDir[i] == 0 ) {
 592                         gaTmpDir[i] = 0;
 593                         continue;
 594                 }
 595
 596                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 597                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 598                 gaTmpDir[i] = gaPageDir[i];
 599         }
 600
 601         // Allocate kernel stack
 602         for(i = KERNEL_STACKS >> 22;
 603                 i < KERNEL_STACKS_END >> 22;
 604                 i ++ )
 605         {
 606                 // Check if directory is allocated
 607                 if( (gaPageDir[i] & 1) == 0 ) {
 608                         gaTmpDir[i] = 0;
 609                         continue;
 610                 }
 611
 612                 // We don't care about other kernel stacks, just the current one
 613                 if( i != kStackBase >> 22 ) {
 614                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 615                         gaTmpDir[i] = 0;
 616                         continue;
 617                 }
 618
 619                 // Create a copy
 620                 gaTmpDir[i] = MM_AllocPhys() | 3;
 621                 INVLPG( &gaTmpTable[i*1024] );
 622                 for( j = 0; j < 1024; j ++ )
 623                 {
 624                         // Is the page allocated? If not, skip
 625                         if( !(gaPageTable[i*1024+j] & 1) ) {
 626                                 gaTmpTable[i*1024+j] = 0;
 627                                 continue;
 628                         }
 629
 630                         // We don't care about other kernel stacks
 631                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 632                                 gaTmpTable[i*1024+j] = 0;
 633                                 continue;
 634                         }
 635
 636                         // Allocate page
 637                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 638
 639                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 640
 641                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 642                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 643                         MM_FreeTemp( (Uint)tmp );
 644                 }
 645         }
 646
 647         ret = *gpTmpCR3 & ~0xFFF;
 648         RELEASE( &gilTempFractal );
 649
 650         //LEAVE('x', ret);
 651         return ret;
 652 }
 653
 654 /**
 655  * \fn tVAddr MM_NewKStack()
 656  * \brief Create a new kernel stack
 657  */
 658 tVAddr MM_NewKStack()
 659 {
 660         tVAddr  base = KERNEL_STACKS;
 661         Uint    i;
 662         for(;base<KERNEL_STACKS_END;base+=KERNEL_STACK_SIZE)
 663         {
 664                 if(MM_GetPhysAddr(base) != 0)   continue;
 665                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 666                         MM_Allocate(base+i);
 667                 }
 668                 return base+KERNEL_STACK_SIZE;
 669         }
 670         Warning("MM_NewKStack - No address space left\n");
 671         return 0;
 672 }
 673
 674 /**
 675  * \fn tVAddr MM_NewWorkerStack()
 676  * \brief Creates a new worker stack
 677  */
 678 tVAddr MM_NewWorkerStack()
 679 {
 680         Uint    esp, ebp;
 681         Uint    oldstack;
 682         Uint    base, addr;
 683          int    i, j;
 684         Uint    *tmpPage;
 685         tPAddr  pages[WORKER_STACK_SIZE>>12];
 686
 687         // Get the old ESP and EBP
 688         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 689         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 690
 691         // Find a free worker stack address
 692         for(base = giLastUsedWorker; base < NUM_WORKER_STACKS; base++)
 693         {
 694                 // Used block
 695                 if( gWorkerStacks[base/32] == -1 ) {
 696                         base += 31;     base &= ~31;
 697                         base --;        // Counteracted by the base++
 698                         continue;
 699                 }
 700                 // Used stack
 701                 if( gWorkerStacks[base/32] & (1 << base) ) {
 702                         continue;
 703                 }
 704                 break;
 705         }
 706         if(base >= NUM_WORKER_STACKS) {
 707                 Warning("Uh-oh! Out of worker stacks");
 708                 return 0;
 709         }
 710
 711         // It's ours now!
 712         gWorkerStacks[base/32] |= (1 << base);
 713         // Make life easier for later calls
 714         giLastUsedWorker = base;
 715         // We have one
 716         base = WORKER_STACKS + base * WORKER_STACK_SIZE;
 717         //Log(" MM_NewWorkerStack: base = 0x%x", base);
 718
 719         // Acquire the lock for the temp fractal mappings
 720         LOCK(&gilTempFractal);
 721
 722         // Set the temp fractals to TID0's address space
 723         *gpTmpCR3 = ((Uint)gaInitPageDir - KERNEL_BASE) | 3;
 724         //Log(" MM_NewWorkerStack: *gpTmpCR3 = 0x%x", *gpTmpCR3);
 725         INVLPG( gaTmpDir );
 726
 727
 728         // Check if the directory is mapped (we are assuming that the stacks
 729         // will fit neatly in a directory)
 730         //Log(" MM_NewWorkerStack: gaTmpDir[ 0x%x ] = 0x%x", base>>22, gaTmpDir[ base >> 22 ]);
 731         if(gaTmpDir[ base >> 22 ] == 0) {
 732                 gaTmpDir[ base >> 22 ] = MM_AllocPhys() | 3;
 733                 INVLPG( &gaTmpTable[ (base>>12) & ~0x3FF ] );
 734         }
 735
 736         // Mapping Time!
 737         for( addr = 0; addr < WORKER_STACK_SIZE; addr += 0x1000 )
 738         {
 739                 pages[ addr >> 12 ] = MM_AllocPhys();
 740                 gaTmpTable[ (base + addr) >> 12 ] = pages[addr>>12] | 3;
 741         }
 742         *gpTmpCR3 = 0;
 743         // Release the temp mapping lock
 744         RELEASE(&gilTempFractal);
 745
 746         // Copy the old stack
 747         oldstack = (esp + KERNEL_STACK_SIZE-1) & ~(KERNEL_STACK_SIZE-1);
 748         esp = oldstack - esp;   // ESP as an offset in the stack
 749
 750         // Make `base` be the top of the stack
 751         base += WORKER_STACK_SIZE;
 752
 753         i = (WORKER_STACK_SIZE>>12) - 1;
 754         // Copy the contents of the old stack to the new one, altering the addresses
 755         // `addr` is refering to bytes from the stack base (mem downwards)
 756         for(addr = 0; addr < esp; addr += 0x1000)
 757         {
 758                 Uint    *stack = (Uint*)( oldstack-(addr+0x1000) );
 759                 tmpPage = (void*)MM_MapTemp( pages[i] );
 760                 // Copy old stack
 761                 for(j = 0; j < 1024; j++)
 762                 {
 763                         // Possible Stack address?
 764                         if(oldstack-esp < stack[j] && stack[j] < oldstack)
 765                                 tmpPage[j] = base - (oldstack - stack[j]);
 766                         else    // Seems not, best leave it alone
 767                                 tmpPage[j] = stack[j];
 768                 }
 769                 MM_FreeTemp((tVAddr)tmpPage);
 770                 i --;
 771         }
 772
 773         //Log("MM_NewWorkerStack: RETURN 0x%x", base);
 774         return base;
 775 }
 776
 777 /**
 778  * \fn void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 779  * \brief Sets the flags on a page
 780  */
 781 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 782 {
 783         tTabEnt *ent;
 784         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 785         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 786
 787         ent = &gaPageTable[VAddr >> 12];
 788
 789         // Read-Only
 790         if( Mask & MM_PFLAG_RO )
 791         {
 792                 if( Flags & MM_PFLAG_RO ) {
 793                         *ent &= ~PF_WRITE;
 794                 }
 795                 else {
 796                         gaPageDir[VAddr >> 22] |= PF_WRITE;
 797                         *ent |= PF_WRITE;
 798                 }
 799         }
 800
 801         // Kernel
 802         if( Mask & MM_PFLAG_KERNEL )
 803         {
 804                 if( Flags & MM_PFLAG_KERNEL ) {
 805                         *ent &= ~PF_USER;
 806                 }
 807                 else {
 808                         gaPageDir[VAddr >> 22] |= PF_USER;
 809                         *ent |= PF_USER;
 810                 }
 811         }
 812
 813         // Copy-On-Write
 814         if( Mask & MM_PFLAG_COW )
 815         {
 816                 if( Flags & MM_PFLAG_COW ) {
 817                         *ent &= ~PF_WRITE;
 818                         *ent |= PF_COW;
 819                 }
 820                 else {
 821                         *ent &= ~PF_COW;
 822                         *ent |= PF_WRITE;
 823                 }
 824         }
 825
 826         //Log("MM_SetFlags: *ent = 0x%08x, gaPageDir[%i] = 0x%08x",
 827         //      *ent, VAddr >> 22, gaPageDir[VAddr >> 22]);
 828 }
 829
 830 /**
 831  * \fn tPAddr MM_DuplicatePage(tVAddr VAddr)
 832  * \brief Duplicates a virtual page to a physical one
 833  */
 834 tPAddr MM_DuplicatePage(tVAddr VAddr)
 835 {
 836         tPAddr  ret;
 837         Uint    temp;
 838          int    wasRO = 0;
 839
 840         //ENTER("xVAddr", VAddr);
 841
 842         // Check if mapped
 843         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 844         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 845
 846         // Page Align
 847         VAddr &= ~0xFFF;
 848
 849         // Allocate new page
 850         ret = MM_AllocPhys();
 851
 852         // Write-lock the page (to keep data constistent), saving its R/W state
 853         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 854         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 855         INVLPG( VAddr );
 856
 857         // Copy Data
 858         temp = MM_MapTemp(ret);
 859         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 860         MM_FreeTemp(temp);
 861
 862         // Restore Writeable status
 863         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 864         INVLPG(VAddr);
 865
 866         //LEAVE('X', ret);
 867         return ret;
 868 }
 869
 870 /**
 871  * \fn Uint MM_MapTemp(tPAddr PAddr)
 872  * \brief Create a temporary memory mapping
 873  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 874  */
 875 tVAddr MM_MapTemp(tPAddr PAddr)
 876 {
 877          int    i;
 878
 879         //ENTER("XPAddr", PAddr);
 880
 881         PAddr &= ~0xFFF;
 882
 883         //LOG("gilTempMappings = %i", gilTempMappings);
 884
 885         for(;;)
 886         {
 887                 LOCK( &gilTempMappings );
 888
 889                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 890                 {
 891                         // Check if page used
 892                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 893                         // Mark as used
 894                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 895                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 896                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 897                         RELEASE( &gilTempMappings );
 898                         return TEMP_MAP_ADDR + (i << 12);
 899                 }
 900                 RELEASE( &gilTempMappings );
 901                 Threads_Yield();
 902         }
 903 }
 904
 905 /**
 906  * \fn void MM_FreeTemp(tVAddr PAddr)
 907  * \brief Free's a temp mapping
 908  */
 909 void MM_FreeTemp(tVAddr VAddr)
 910 {
 911          int    i = VAddr >> 12;
 912         //ENTER("xVAddr", VAddr);
 913
 914         if(i >= (TEMP_MAP_ADDR >> 12))
 915                 gaPageTable[ i ] = 0;
 916
 917         //LEAVE('-');
 918 }
 919
 920 /**
 921  * \fn tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 922  * \brief Allocates a contigous number of pages
 923  */
 924 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 925 {
 926          int    i, j;
 927
 928         PAddr &= ~0xFFF;
 929
 930         // Scan List
 931         for( i = 0; i < NUM_HW_PAGES; i ++ )
 932         {
 933                 // Check if addr used
 934                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 935                         continue;
 936
 937                 // Check possible region
 938                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 939                 {
 940                         // If there is an allocated page in the region we are testing, break
 941                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 942                 }
 943                 // Is it all free?
 944                 if( j == Number )
 945                 {
 946                         // Allocate
 947                         for( j = 0; j < Number; j++ ) {
 948                                 MM_RefPhys( PAddr + (j<<12) );
 949                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 950                         }
 951                         return HW_MAP_ADDR + (i<<12);
 952                 }
 953         }
 954         // If we don't find any, return NULL
 955         return 0;
 956 }
 957
 958 /**
 959  * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 960  * \brief Allocates DMA physical memory
 961  * \param Pages Number of pages required
 962  * \param MaxBits       Maximum number of bits the physical address can have
 963  * \param PhysAddr      Pointer to the location to place the physical address allocated
 964  * \return Virtual address allocate
 965  */
 966 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
 967 {
 968         tPAddr  maxCheck = (1 << MaxBits);
 969         tPAddr  phys;
 970         tVAddr  ret;
 971
 972         ENTER("iPages iMaxBits pPhysAddr", Pages, MaxBits, PhysAddr);
 973
 974         // Sanity Check
 975         if(MaxBits < 12 || !PhysAddr) {
 976                 LEAVE('i', 0);
 977                 return 0;
 978         }
 979
 980         // Bound
 981         if(MaxBits >= PHYS_BITS)        maxCheck = -1;
 982
 983         // Fast Allocate
 984         if(Pages == 1 && MaxBits >= PHYS_BITS)
 985         {
 986                 phys = MM_AllocPhys();
 987                 *PhysAddr = phys;
 988                 ret = MM_MapHWPages(phys, 1);
 989                 if(ret == 0) {
 990                         MM_DerefPhys(phys);
 991                         LEAVE('i', 0);
 992                         return 0;
 993                 }
 994                 LEAVE('x', ret);
 995                 return ret;
 996         }
 997
 998         // Slow Allocate
 999         phys = MM_AllocPhysRange(Pages, MaxBits);
1000         // - Was it allocated?
1001         if(phys == 0) {
1002                 LEAVE('i', 0);
1003                 return 0;
1004         }
1005
1006         // Allocated successfully, now map
1007         ret = MM_MapHWPages(phys, Pages);
1008         if( ret == 0 ) {
1009                 // If it didn't map, free then return 0
1010                 for(;Pages--;phys+=0x1000)
1011                         MM_DerefPhys(phys);
1012                 LEAVE('i', 0);
1013                 return 0;
1014         }
1015
1016         *PhysAddr = phys;
1017         LEAVE('x', ret);
1018         return ret;
1019 }
1020
1021 /**
1022  * \fn void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1023  * \brief Unmap a hardware page
1024  */
1025 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
1026 {
1027          int    i, j;
1028
1029         //Log_Debug("VirtMem", "MM_UnmapHWPages: (VAddr=0x%08x, Number=%i)", VAddr, Number);
1030
1031         // Sanity Check
1032         if(VAddr < HW_MAP_ADDR || VAddr+Number*0x1000 > HW_MAP_MAX)     return;
1033
1034         i = VAddr >> 12;
1035
1036         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
1037
1038
1039         for( j = 0; j < Number; j++ )
1040         {
1041                 MM_DerefPhys( gaPageTable[ i + j ] & ~0xFFF );
1042                 gaPageTable[ i + j ] = 0;
1043         }
1044
1045         RELEASE( &gilTempMappings );
1046 }
1047
1048 // --- EXPORTS ---
1049 EXPORT(MM_GetPhysAddr);
1050 EXPORT(MM_Map);
1051 //EXPORT(MM_Unmap);
1052 EXPORT(MM_MapHWPages);
1053 EXPORT(MM_AllocDMA);
1054 EXPORT(MM_UnmapHWPages);