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