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 #include <common.h>
  13 #include <mm_phys.h>
  14 #include <proc.h>
  15
  16 #define KERNEL_STACKS   0xF0000000
  17 #define KERNEL_STACK_SIZE       0x00002000
  18 #define KERNEL_STACK_END        0xFD000000
  19 #define PAGE_TABLE_ADDR 0xFD000000
  20 #define PAGE_DIR_ADDR   0xFD3F4000
  21 #define PAGE_CR3_ADDR   0xFD3F4FD0
  22 #define TMP_CR3_ADDR    0xFD3F4FD4      // Part of core instead of temp
  23 #define TMP_DIR_ADDR    0xFD3F5000      // Same
  24 #define TMP_TABLE_ADDR  0xFD400000
  25 #define HW_MAP_ADDR             0xFD800000
  26 #define HW_MAP_MAX              0xFEFF0000
  27 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  28 #define TEMP_MAP_ADDR   0xFEFF0000      // Allows 16 "temp" pages
  29 #define NUM_TEMP_PAGES  16
  30
  31 #define PF_PRESENT      0x1
  32 #define PF_WRITE        0x2
  33 #define PF_USER         0x4
  34 #define PF_COW          0x200
  35 #define PF_PAGED        0x400
  36
  37 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  38
  39 // === IMPORTS ===
  40 extern Uint32   gaInitPageDir[1024];
  41 extern Uint32   gaInitPageTable[1024];
  42
  43 // === PROTOTYPES ===
  44 void    MM_PreinitVirtual();
  45 void    MM_InstallVirtual();
  46 void    MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs);
  47 void    MM_DumpTables(tVAddr Start, tVAddr End);
  48 tPAddr  MM_DuplicatePage(Uint VAddr);
  49
  50 // === GLOBALS ===
  51 tPAddr  *gaPageTable = (void*)PAGE_TABLE_ADDR;
  52 tPAddr  *gaPageDir = (void*)PAGE_DIR_ADDR;
  53 tPAddr  *gaPageCR3 = (void*)PAGE_CR3_ADDR;
  54 tPAddr  *gaTmpTable = (void*)TMP_TABLE_ADDR;
  55 tPAddr  *gaTmpDir = (void*)TMP_DIR_ADDR;
  56 tPAddr  *gTmpCR3 = (void*)TMP_CR3_ADDR;
  57  int    gilTempMappings = 0;
  58
  59 // === CODE ===
  60 /**
  61  * \fn void MM_PreinitVirtual()
  62  * \brief Maps the fractal mappings
  63  */
  64 void MM_PreinitVirtual()
  65 {
  66         gaInitPageDir[ 0 ] = 0;
  67         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((Uint)&gaInitPageDir - KERNEL_BASE) | 3;
  68 }
  69
  70 /**
  71  * \fn void MM_InstallVirtual()
  72  * \brief Sets up the constant page mappings
  73  */
  74 void MM_InstallVirtual()
  75 {
  76          int    i;
  77
  78         // --- Pre-Allocate kernel tables
  79         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
  80         {
  81                 if( gaPageDir[ i ] )    continue;
  82                 // Skip stack tables, they are process unique
  83                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACK_END >> 22) {
  84                         gaPageDir[ i ] = 0;
  85                         continue;
  86                 }
  87                 // Preallocate table
  88                 gaPageDir[ i ] = MM_AllocPhys() | 3;
  89                 INVLPG( &gaPageTable[i*1024] );
  90                 memset( &gaPageTable[i*1024], 0, 0x1000 );
  91         }
  92 }
  93
  94 /**
  95  * \fn void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
  96  * \brief Called on a page fault
  97  */
  98 void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
  99 {
 100         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 101
 102         // -- Check for COW --
 103         if( gaPageDir  [Addr>>22] & PF_PRESENT
 104          && gaPageTable[Addr>>12] & PF_PRESENT
 105          && gaPageTable[Addr>>12] & PF_COW )
 106         {
 107                 tPAddr  paddr;
 108                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 109                 {
 110                         gaPageTable[Addr>>12] &= ~PF_COW;
 111                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 112                 }
 113                 else
 114                 {
 115                         paddr = MM_DuplicatePage( Addr );
 116                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 117                         gaPageTable[Addr>>12] &= PF_USER;
 118                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 119                 }
 120                 INVLPG( Addr & ~0xFFF );
 121                 //LEAVE('-')
 122                 return;
 123         }
 124
 125         // -- Check Error Code --
 126         if(ErrorCode & 8)
 127                 Warning("Reserved Bits Trashed!");
 128         else
 129         {
 130                 Warning("%s %s %s memory%s",
 131                         (ErrorCode&4?"User":"Kernel"),
 132                         (ErrorCode&2?"write to":"read from"),
 133                         (ErrorCode&1?"bad/locked":"non-present"),
 134                         (ErrorCode&16?" (Instruction Fetch)":"")
 135                         );
 136         }
 137
 138         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 139         if( gaPageDir[Addr>>22] & PF_PRESENT )
 140                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 141
 142         MM_DumpTables(0, -1);
 143
 144         Panic("Page Fault at 0x%x\n", Regs->eip);
 145 }
 146
 147 /**
 148  * \fn void MM_DumpTables(Uint Start, Uint End)
 149  * \brief Dumps the layout of the page tables
 150  */
 151 void MM_DumpTables(tVAddr Start, tVAddr End)
 152 {
 153         tVAddr  rangeStart = 0;
 154         tPAddr  expected = 0;
 155         tVAddr  curPos;
 156         Uint    page;
 157         const tPAddr    MASK = ~0xF98;
 158
 159         Start >>= 12;   End >>= 12;
 160         for(page = Start, curPos = Start<<12;
 161                 page < End;
 162                 curPos += 0x1000, page++)
 163         {
 164                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 165                 ||  !(gaPageTable[page] & PF_PRESENT)
 166                 ||  (gaPageTable[page] & MASK) != expected)
 167                 {
 168                         if(expected) {
 169                                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 170                                         rangeStart, curPos - 1,
 171                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 172                                         (expected & ~0xFFF) - 1,
 173                                         (expected & PF_PAGED ? "p" : "-"),
 174                                         (expected & PF_COW ? "C" : "-"),
 175                                         (expected & PF_USER ? "U" : "-"),
 176                                         (expected & PF_WRITE ? "W" : "-")
 177                                         );
 178                                 expected = 0;
 179                         }
 180                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 181                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 182
 183                         expected = (gaPageTable[page] & MASK);
 184                         rangeStart = curPos;
 185                 }
 186                 if(expected)    expected += 0x1000;
 187         }
 188
 189         if(expected) {
 190                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 191                         rangeStart, curPos - 1,
 192                         gaPageTable[rangeStart>>12] & ~0xFFF,
 193                         (expected & ~0xFFF) - 1,
 194                         (expected & PF_PAGED ? "p" : "-"),
 195                         (expected & PF_COW ? "C" : "-"),
 196                         (expected & PF_USER ? "U" : "-"),
 197                         (expected & PF_WRITE ? "W" : "-")
 198                         );
 199                 expected = 0;
 200         }
 201 }
 202
 203 /**
 204  * \fn tPAddr MM_Allocate(Uint VAddr)
 205  */
 206 tPAddr MM_Allocate(Uint VAddr)
 207 {
 208         tPAddr  paddr;
 209         // Check if the directory is mapped
 210         if( gaPageDir[ VAddr >> 22 ] == 0 )
 211         {
 212                 // Allocate directory
 213                 paddr = MM_AllocPhys();
 214                 if( paddr == 0 ) {
 215                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 216                         return 0;
 217                 }
 218                 // Map
 219                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 220                 // Mark as user
 221                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 222
 223                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 224                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 225         }
 226         // Check if the page is already allocated
 227         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 228                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 229                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 230         }
 231
 232         // Allocate
 233         paddr = MM_AllocPhys();
 234         if( paddr == 0 ) {
 235                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 236                         VAddr, __builtin_return_address(0));
 237                 return 0;
 238         }
 239         // Map
 240         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 241         // Mark as user
 242         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 243         // Invalidate Cache for address
 244         INVLPG( VAddr & ~0xFFF );
 245
 246         return paddr;
 247 }
 248
 249 /**
 250  * \fn void MM_Deallocate(Uint VAddr)
 251  */
 252 void MM_Deallocate(Uint VAddr)
 253 {
 254         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 255                 Warning("MM_Deallocate - Directory not mapped");
 256                 return;
 257         }
 258
 259         if(gaPageTable[ VAddr >> 12 ] == 0) {
 260                 Warning("MM_Deallocate - Page is not allocated");
 261                 return;
 262         }
 263
 264         // Dereference page
 265         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 266         // Clear page
 267         gaPageTable[ VAddr >> 12 ] = 0;
 268 }
 269
 270 /**
 271  * \fn tPAddr MM_GetPhysAddr(Uint Addr)
 272  * \brief Checks if the passed address is accesable
 273  */
 274 tPAddr MM_GetPhysAddr(Uint Addr)
 275 {
 276         if( !(gaPageDir[Addr >> 22] & 1) )
 277                 return 0;
 278         if( !(gaPageTable[Addr >> 12] & 1) )
 279                 return 0;
 280         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 281 }
 282
 283 /**
 284  * \fn void MM_SetCR3(Uint CR3)
 285  * \brief Sets the current process space
 286  */
 287 void MM_SetCR3(Uint CR3)
 288 {
 289         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 290 }
 291
 292 /**
 293  * \fn int MM_Map(Uint VAddr, tPAddr PAddr)
 294  * \brief Map a physical page to a virtual one
 295  */
 296 int MM_Map(Uint VAddr, tPAddr PAddr)
 297 {
 298         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 299         // Sanity check
 300         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 301                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 302                 //LEAVE('i', 0);
 303                 return 0;
 304         }
 305
 306         // Align addresses
 307         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 308
 309         // Check if the directory is mapped
 310         if( gaPageDir[ VAddr >> 22 ] == 0 )
 311         {
 312                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 313
 314                 // Mark as user
 315                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 316
 317                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 318                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 319         }
 320         // Check if the page is already allocated
 321         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 322                 Warning("MM_Map - Allocating to used address");
 323                 //LEAVE('i', 0);
 324                 return 0;
 325         }
 326
 327         // Map
 328         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 329         // Mark as user
 330         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 331
 332         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 333         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 334
 335         // Reference
 336         MM_RefPhys( PAddr );
 337
 338         //LOG("INVLPG( 0x%x )", VAddr);
 339         INVLPG( VAddr );
 340
 341         //LEAVE('i', 1);
 342         return 1;
 343 }
 344
 345 /**
 346  * \fn Uint MM_ClearUser()
 347  * \brief Clear user's address space
 348  */
 349 Uint MM_ClearUser()
 350 {
 351         Uint    i, j;
 352
 353         // Copy Directories
 354         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 355         {
 356                 // Check if directory is not allocated
 357                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 358                         gaPageDir[i] = 0;
 359                         continue;
 360                 }
 361
 362
 363                 for( j = 0; j < 1024; j ++ )
 364                 {
 365                         if( gaPageTable[i*1024+j] & 1 )
 366                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 367                         gaPageTable[i*1024+j] = 0;
 368                 }
 369
 370                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 371         }
 372
 373
 374         return *gTmpCR3;
 375 }
 376
 377 /**
 378  * \fn Uint MM_Clone()
 379  * \brief Clone the current address space
 380  */
 381 Uint MM_Clone()
 382 {
 383         Uint    i, j;
 384         Uint    kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 385         void    *tmp;
 386
 387         //ENTER("");
 388
 389         // Create Directory Table
 390         *gTmpCR3 = MM_AllocPhys() | 3;
 391         INVLPG( gaTmpDir );
 392         //LOG("Allocated Directory (%x)", *gTmpCR3);
 393         memsetd( gaTmpDir, 0, 1024 );
 394
 395         // Copy Tables
 396         for(i=0;i<768;i++)
 397         {
 398                 // Check if table is allocated
 399                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 400                         gaTmpDir[i] = 0;
 401                         continue;
 402                 }
 403
 404                 // Allocate new table
 405                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 406                 INVLPG( &gaTmpTable[i*1024] );
 407                 // Fill
 408                 for( j = 0; j < 1024; j ++ )
 409                 {
 410                         if( !(gaPageTable[i*1024+j] & PF_PRESENT) ) {
 411                                 gaTmpTable[i*1024+j] = 0;
 412                                 continue;
 413                         }
 414
 415                         // Refrence old page
 416                         MM_RefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 417                         // Add to new table
 418                         if(gaPageTable[i*1024+j] & PF_WRITE) {
 419                                 gaTmpTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 420                                 gaPageTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 421                         }
 422                         else
 423                                 gaTmpTable[i*1024+j] = gaPageTable[i*1024+j];
 424                 }
 425         }
 426
 427         // Map in kernel tables (and make fractal mapping)
 428         for( i = 768; i < 1024; i ++ )
 429         {
 430                 // Fractal
 431                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 432                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 433                         continue;
 434                 }
 435
 436                 if( gaPageDir[i] == 0 ) {
 437                         gaTmpDir[i] = 0;
 438                         continue;
 439                 }
 440
 441                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 442                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 443                 gaTmpDir[i] = gaPageDir[i];
 444         }
 445
 446         // Allocate kernel stack
 447         for(i = KERNEL_STACKS >> 22;
 448                 i < KERNEL_STACK_END >> 22;
 449                 i ++ )
 450         {
 451                 // Check if directory is allocated
 452                 if( (gaPageDir[i] & 1) == 0 ) {
 453                         gaTmpDir[i] = 0;
 454                         continue;
 455                 }
 456
 457                 // We don't care about other kernel stacks, just the current one
 458                 if( i != kStackBase >> 22 ) {
 459                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 460                         gaTmpDir[i] = 0;
 461                         continue;
 462                 }
 463
 464                 // Create a copy
 465                 gaTmpDir[i] = MM_AllocPhys() | 3;
 466                 INVLPG( &gaTmpTable[i*1024] );
 467                 for( j = 0; j < 1024; j ++ )
 468                 {
 469                         // Is the page allocated? If not, skip
 470                         if( !(gaPageTable[i*1024+j] & 1) ) {
 471                                 gaTmpTable[i*1024+j] = 0;
 472                                 continue;
 473                         }
 474
 475                         // We don't care about other kernel stacks
 476                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 477                                 gaTmpTable[i*1024+j] = 0;
 478                                 continue;
 479                         }
 480
 481                         // Allocate page
 482                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 483
 484                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 485
 486                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 487                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 488                         MM_FreeTemp( (Uint)tmp );
 489                 }
 490         }
 491
 492         //LEAVE('x', *gTmpCR3 & ~0xFFF);
 493         return *gTmpCR3 & ~0xFFF;
 494 }
 495
 496 /**
 497  * \fn Uint MM_NewKStack()
 498  * \brief Create a new kernel stack
 499  */
 500 Uint MM_NewKStack()
 501 {
 502         Uint    base = KERNEL_STACKS;
 503         Uint    i;
 504         for(;base<KERNEL_STACK_END;base+=KERNEL_STACK_SIZE)
 505         {
 506                 if(MM_GetPhysAddr(base) != 0)   continue;
 507                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 508                         MM_Allocate(base+i);
 509                 }
 510                 return base+KERNEL_STACK_SIZE;
 511         }
 512         Warning("MM_NewKStack - No address space left\n");
 513         return 0;
 514 }
 515
 516 /**
 517  * \fn void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 518  * \brief Sets the flags on a page
 519  */
 520 void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 521 {
 522         tPAddr  *ent;
 523         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 524         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 525
 526         ent = &gaPageTable[VAddr >> 12];
 527
 528         // Read-Only
 529         if( Mask & MM_PFLAG_RO )
 530         {
 531                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 532                 else    *ent |= PF_WRITE;
 533         }
 534
 535         // Kernel
 536         if( Mask & MM_PFLAG_KERNEL )
 537         {
 538                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 539                 else    *ent |= PF_USER;
 540         }
 541
 542         // Copy-On-Write
 543         if( Mask & MM_PFLAG_COW )
 544         {
 545                 if( Flags & MM_PFLAG_COW ) {
 546                         *ent &= ~PF_WRITE;
 547                         *ent |= PF_COW;
 548                 }
 549                 else {
 550                         *ent &= ~PF_COW;
 551                         *ent |= PF_WRITE;
 552                 }
 553         }
 554 }
 555
 556 /**
 557  * \fn tPAddr MM_DuplicatePage(Uint VAddr)
 558  * \brief Duplicates a virtual page to a physical one
 559  */
 560 tPAddr MM_DuplicatePage(Uint VAddr)
 561 {
 562         tPAddr  ret;
 563         Uint    temp;
 564          int    wasRO = 0;
 565
 566         // Check if mapped
 567         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 568         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 569
 570         // Page Align
 571         VAddr &= ~0xFFF;
 572
 573         // Allocate new page
 574         ret = MM_AllocPhys();
 575
 576         // Write-lock the page (to keep data constistent), saving its R/W state
 577         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 578         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 579         INVLPG( VAddr );
 580
 581         // Copy Data
 582         temp = MM_MapTemp(ret);
 583         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 584         MM_FreeTemp(temp);
 585
 586         // Restore Writeable status
 587         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 588         INVLPG(VAddr);
 589
 590         return ret;
 591 }
 592
 593 /**
 594  * \fn Uint MM_MapTemp(tPAddr PAddr)
 595  * \brief Create a temporary memory mapping
 596  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 597  */
 598 Uint MM_MapTemp(tPAddr PAddr)
 599 {
 600          int    i;
 601
 602         //ENTER("XPAddr", PAddr);
 603
 604         PAddr &= ~0xFFF;
 605
 606         //LOG("gilTempMappings = %i", gilTempMappings);
 607
 608         for(;;)
 609         {
 610                 LOCK( &gilTempMappings );
 611
 612                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 613                 {
 614                         // Check if page used
 615                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 616                         // Mark as used
 617                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 618                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 619                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 620                         RELEASE( &gilTempMappings );
 621                         return TEMP_MAP_ADDR + (i << 12);
 622                 }
 623                 RELEASE( &gilTempMappings );
 624                 Threads_Yield();
 625         }
 626 }
 627
 628 /**
 629  * \fn void MM_FreeTemp(Uint PAddr)
 630  * \brief Free's a temp mapping
 631  */
 632 void MM_FreeTemp(Uint VAddr)
 633 {
 634          int    i = VAddr >> 12;
 635         //ENTER("xVAddr", VAddr);
 636
 637         if(i >= (TEMP_MAP_ADDR >> 12))
 638                 gaPageTable[ i ] = 0;
 639
 640         //LEAVE('-');
 641 }
 642
 643 /**
 644  * \fn Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 645  * \brief Allocates a contigous number of pages
 646  */
 647 Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 648 {
 649          int    i, j;
 650
 651         PAddr &= ~0xFFF;
 652
 653         // Scan List
 654         for( i = 0; i < NUM_HW_PAGES; i ++ )
 655         {
 656                 // Check if addr used
 657                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 658                         continue;
 659
 660                 // Check possible region
 661                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 662                 {
 663                         // If there is an allocated page in the region we are testing, break
 664                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 665                 }
 666                 // Is it all free?
 667                 if( j == Number )
 668                 {
 669                         // Allocate
 670                         for( j = 0; j < Number; j++ ) {
 671                                 MM_RefPhys( PAddr + (j<<12) );
 672                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 673                         }
 674                         return HW_MAP_ADDR + (i<<12);
 675                 }
 676         }
 677         // If we don't find any, return NULL
 678         return 0;
 679 }
 680
 681 /**
 682  * \fn void MM_UnmapHWPage(Uint VAddr, Uint Number)
 683  * \brief Unmap a hardware page
 684  */
 685 void MM_UnmapHWPage(Uint VAddr, Uint Number)
 686 {
 687          int    i, j;
 688         // Sanity Check
 689         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 690
 691         i = VAddr >> 12;
 692
 693         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 694
 695         for( j = 0; j < Number; j++ )
 696         {
 697                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 698                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 699         }
 700
 701         RELEASE( &gilTempMappings );
 702 }
 703
 704 // --- EXPORTS ---
 705 EXPORT(MM_GetPhysAddr);
 706 EXPORT(MM_Map);
 707 //EXPORT(MM_Unmap);
 708 EXPORT(MM_MapHWPage);
 709 EXPORT(MM_UnmapHWPage);