4 * Virtual Memory Manager
12 #define PHYS_BITS 52 // TODO: Move out
19 #define PADDR_MASK 0x7FFFFFFF##FFFFF000
20 #define PAGE_MASK (((Uint)1 << 36)-1)
21 #define TABLE_MASK (((Uint)1 << 27)-1)
22 #define PDP_MASK (((Uint)1 << 18)-1)
23 #define PML4_MASK (((Uint)1 << 9)-1)
25 #define PF_PRESENT 0x001
26 #define PF_WRITE 0x002
28 #define PF_LARGE 0x000
30 #define PF_PAGED 0x400
31 #define PF_NX 0x80000000##00000000
34 #define PAGETABLE(idx) (*((tPAddr*)MM_FRACTAL_BASE+((idx)&PAGE_MASK)))
35 #define PAGEDIR(idx) PAGETABLE((MM_FRACTAL_BASE>>12)+((idx)&TABLE_MASK))
36 #define PAGEDIRPTR(idx) PAGEDIR((MM_FRACTAL_BASE>>21)+((idx)&PDP_MASK))
37 #define PAGEMAPLVL4(idx) PAGEDIRPTR((MM_FRACTAL_BASE>>30)+((idx)&PML4_MASK))
39 #define TMPTABLE(idx) (*((tPAddr*)MM_TMPFRAC_BASE+((idx)&PAGE_MASK)))
40 #define TMPDIR(idx) TMPTABLE((MM_FRACTAL_BASE>>12)+((idx)&TABLE_MASK))
41 #define TMPDIRPTR(idx) TMPDIR((MM_FRACTAL_BASE>>21)+((idx)&PDP_MASK))
42 #define TMPMAPLVL4(idx) TMPDIRPTR((MM_FRACTAL_BASE>>30)+((idx)&PML4_MASK))
43 #define TMPCR3() PAGETABLE(MM_TMPFRAC_BASE>>12)
45 #define INVLPG(__addr) __asm__ __volatile__ ("invlpg (%0)"::"r"(__addr));
48 //tPAddr * const gaPageTable = MM_FRACTAL_BASE;
51 extern tPAddr gInitialPML4[512];
54 void MM_InitVirt(void);
55 //void MM_FinishVirtualInit(void);
56 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
57 void MM_DumpTables(tVAddr Start, tVAddr End);
58 int MM_GetPageEntryPtr(tVAddr Addr, BOOL bTemp, BOOL bAllocate, BOOL bLargePage, tPAddr **Pointer);
59 // int MM_Map(tVAddr VAddr, tPAddr PAddr);
60 void MM_Unmap(tVAddr VAddr);
61 void MM_ClearUser(void);
62 int MM_GetPageEntry(tVAddr Addr, tPAddr *Phys, Uint *Flags);
65 tMutex glMM_TempFractalLock;
68 void MM_InitVirt(void)
70 MM_DumpTables(0, -1L);
73 void MM_FinishVirtualInit(void)
78 * \brief Called on a page fault
80 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
82 // TODO: Implement Copy-on-Write
84 if( gaPageDir [Addr>>22] & PF_PRESENT
85 && gaPageTable[Addr>>12] & PF_PRESENT
86 && gaPageTable[Addr>>12] & PF_COW )
89 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
91 gaPageTable[Addr>>12] &= ~PF_COW;
92 gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
96 //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
97 paddr = MM_DuplicatePage( Addr );
98 MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
99 gaPageTable[Addr>>12] &= PF_USER;
100 gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
103 INVLPG( Addr & ~0xFFF );
108 // If it was a user, tell the thread handler
110 Warning("%s %s %s memory%s",
111 (ErrorCode&4?"User":"Kernel"),
112 (ErrorCode&2?"write to":"read from"),
113 (ErrorCode&1?"bad/locked":"non-present"),
114 (ErrorCode&16?" (Instruction Fetch)":"")
116 Warning("User Pagefault: Instruction at %04x:%08x accessed %p",
117 Regs->CS, Regs->RIP, Addr);
118 __asm__ __volatile__ ("sti"); // Restart IRQs
119 // Threads_SegFault(Addr);
125 // -- Check Error Code --
127 Warning("Reserved Bits Trashed!");
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)":"")
138 Log("Code at %p accessed %p", Regs->RIP, Addr);
139 // Print Stack Backtrace
140 // Error_Backtrace(Regs->RIP, Regs->RBP);
142 MM_DumpTables(0, -1);
144 __asm__ __volatile__ ("cli");
150 * \brief Dumps the layout of the page tables
152 void MM_DumpTables(tVAddr Start, tVAddr End)
154 const tPAddr CHANGEABLE_BITS = 0xFF8;
155 const tPAddr MASK = ~CHANGEABLE_BITS; // Physical address and access bits
156 tVAddr rangeStart = 0;
157 tPAddr expected = CHANGEABLE_BITS; // MASK is used because it's not a vaild value
161 Log("Table Entries: (%p to %p)", Start, End);
163 End &= (1L << 48) - 1;
165 Start >>= 12; End >>= 12;
167 for(page = Start, curPos = Start<<12;
169 curPos += 0x1000, page++)
171 if( curPos == 0x800000000000L )
172 curPos = 0xFFFF800000000000L;
174 //Debug("&PAGEMAPLVL4(%i page>>27) = %p", page>>27, &PAGEMAPLVL4(page>>27));
175 //Debug("&PAGEDIRPTR(%i page>>18) = %p", page>>18, &PAGEDIRPTR(page>>18));
176 //Debug("&PAGEDIR(%i page>>9) = %p", page>>9, &PAGEDIR(page>>9));
177 //Debug("&PAGETABLE(%i page) = %p", page, &PAGETABLE(page));
181 !(PAGEMAPLVL4(page>>27) & PF_PRESENT)
182 || !(PAGEDIRPTR(page>>18) & PF_PRESENT)
183 || !(PAGEDIR(page>>9) & PF_PRESENT)
184 || !(PAGETABLE(page) & PF_PRESENT)
185 || (PAGETABLE(page) & MASK) != expected)
187 if(expected != CHANGEABLE_BITS) {
188 Log("%016x-0x%016x => %013x-%013x (%c%c%c%c)",
189 rangeStart, curPos - 1,
190 PAGETABLE(rangeStart>>12) & ~0xFFF,
191 (expected & ~0xFFF) - 1,
192 (expected & PF_PAGED ? 'p' : '-'),
193 (expected & PF_COW ? 'C' : '-'),
194 (expected & PF_USER ? 'U' : '-'),
195 (expected & PF_WRITE ? 'W' : '-')
197 expected = CHANGEABLE_BITS;
199 if( !(PAGEMAPLVL4(page>>27) & PF_PRESENT) ) {
200 page += (1 << 27) - 1;
201 curPos += (1L << 39) - 0x1000;
202 //Debug("pml4 ent unset (page = 0x%x now)", page);
205 if( !(PAGEDIRPTR(page>>18) & PF_PRESENT) ) {
206 page += (1 << 18) - 1;
207 curPos += (1L << 30) - 0x1000;
208 //Debug("pdp ent unset (page = 0x%x now)", page);
211 if( !(PAGEDIR(page>>9) & PF_PRESENT) ) {
212 page += (1 << 9) - 1;
213 curPos += (1L << 21) - 0x1000;
214 //Debug("pd ent unset (page = 0x%x now)", page);
217 if( !(PAGETABLE(page) & PF_PRESENT) ) continue;
219 expected = (PAGETABLE(page) & MASK);
222 if(expected != CHANGEABLE_BITS)
226 if(expected != CHANGEABLE_BITS) {
227 Log("%016x-%016x => %013x-%013x (%s%s%s%s)",
228 rangeStart, curPos - 1,
229 PAGETABLE(rangeStart>>12) & ~0xFFF,
230 (expected & ~0xFFF) - 1,
231 (expected & PF_PAGED ? "p" : "-"),
232 (expected & PF_COW ? "C" : "-"),
233 (expected & PF_USER ? "U" : "-"),
234 (expected & PF_WRITE ? "W" : "-")
241 * \brief Get a pointer to a page entry
242 * \param Addr Virtual Address
243 * \param bTemp Use the Temporary fractal mapping
244 * \param bAllocate Allocate entries
245 * \param bLargePage Request a large page
246 * \param Pointer Location to place the calculated pointer
247 * \return Page size, or -ve on error
249 int MM_GetPageEntryPtr(tVAddr Addr, BOOL bTemp, BOOL bAllocate, BOOL bLargePage, tPAddr **Pointer)
253 const int ADDR_SIZES[] = {39, 30, 21, 12};
254 const int nADDR_SIZES = sizeof(ADDR_SIZES)/sizeof(ADDR_SIZES[0]);
258 pmlevels[3] = (void*)MM_TMPFRAC_BASE; // Temporary Page Table
260 pmlevels[3] = (void*)MM_FRACTAL_BASE; // Page Table
261 pmlevels[2] = &pmlevels[3][(MM_FRACTAL_BASE>>12)&PAGE_MASK]; // PDIR
262 pmlevels[1] = &pmlevels[2][(MM_FRACTAL_BASE>>21)&TABLE_MASK]; // PDPT
263 pmlevels[0] = &pmlevels[1][(MM_FRACTAL_BASE>>30)&PDP_MASK]; // PML4
264 // Log("pmlevels = {%p, %p, %p, %p}",
265 // MM_FRACTAL_BASE>>30, MM_FRACTAL_BASE>>21, MM_FRACTAL_BASE>>12, MM_FRACTAL_BASE);
266 // Log("pmlevels = {%p, %p, %p, %p}",
267 // pmlevels[0], pmlevels[1], pmlevels[2], pmlevels[3]);
270 Addr &= (1ULL << 48)-1;
272 for( i = 0; i < nADDR_SIZES-1; i ++ )
275 // Check for a large page
276 if( (Addr & ((1ULL << ADDR_SIZES[i])-1)) == 0 && bLargePage )
278 if(Pointer) *Pointer = &pmlevels[i][Addr >> ADDR_SIZES[i]];
279 return ADDR_SIZES[i];
281 // Log("&pmlevels[%i][0x%llx (>> %i)] = %p", i, Addr >> ADDR_SIZES[i], ADDR_SIZES[i],
282 // &pmlevels[i][Addr >> ADDR_SIZES[i]]);
283 // Allocate an entry if required
284 if( !(pmlevels[i][Addr >> ADDR_SIZES[i]] & 1) )
286 if( !bAllocate ) return -4; // If allocation is not requested, error
287 tmp = MM_AllocPhys();
289 pmlevels[i][Addr >> ADDR_SIZES[i]] = tmp | 3;
290 INVLPG( &pmlevels[i+1][ (Addr>>ADDR_SIZES[i])<<9 ] );
291 memset( &pmlevels[i+1][ (Addr>>ADDR_SIZES[i])<<9 ], 0, 0x1000 );
293 else if( pmlevels[i][Addr >> ADDR_SIZES[i]] & PF_LARGE )
295 if( (Addr & ((1ULL << ADDR_SIZES[i])-1)) != 0 )
296 return -3; // Alignment
297 if(Pointer) *Pointer = &pmlevels[i][Addr >> ADDR_SIZES[i]];
298 return ADDR_SIZES[i]; // Large page warning
302 // And, set the page table entry
303 if(Pointer) *Pointer = &pmlevels[i][Addr >> ADDR_SIZES[i]];
304 return ADDR_SIZES[i];
308 * \brief Map a physical page to a virtual one
310 int MM_Map(tVAddr VAddr, tPAddr PAddr)
315 ENTER("xVAddr xPAddr", VAddr, PAddr);
317 // Get page pointer (Allow allocating)
318 rv = MM_GetPageEntryPtr(VAddr, 0, 1, 0, &ent);
319 if(rv < 0) LEAVE_RET('i', 0);
333 * \brief Removed a mapped page
335 void MM_Unmap(tVAddr VAddr)
338 if( !(PAGEMAPLVL4(VAddr >> 39) & 1) ) return ;
340 if( !(PAGEDIRPTR(VAddr >> 30) & 1) ) return ;
342 if( !(PAGEDIR(VAddr >> 21) & 1) ) return ;
344 PAGETABLE(VAddr >> PTAB_SHIFT) = 0;
349 * \brief Allocate a block of memory at the specified virtual address
351 tPAddr MM_Allocate(tVAddr VAddr)
355 ENTER("xVAddr", VAddr);
357 // NOTE: This is hack, but I like my dumps to be neat
359 MM_GetPageEntryPtr(VAddr, 0, 1, 0, NULL);
361 if( !MM_Map(VAddr, 0) ) // Make sure things are allocated
363 Warning("MM_Allocate: Unable to map, tables did not initialise");
370 ret = MM_AllocPhys();
371 LOG("ret = %x", ret);
377 if( !MM_Map(VAddr, ret) )
379 Warning("MM_Allocate: Unable to map. Strange, we should have errored earlier");
390 * \brief Deallocate a page at a virtual address
392 void MM_Deallocate(tVAddr VAddr)
396 phys = MM_GetPhysAddr(VAddr);
405 * \brief Get the page table entry of a virtual address
406 * \param Addr Virtual Address
407 * \param Phys Location to put the physical address
408 * \param Flags Flags on the entry (set to zero if unmapped)
409 * \return Size of the entry (in address bits) - 12 = 4KiB page
411 int MM_GetPageEntry(tVAddr Addr, tPAddr *Phys, Uint *Flags)
416 if(!Phys || !Flags) return 0;
418 ret = MM_GetPageEntryPtr(Addr, 0, 0, 0, &ptr);
419 if( ret < 0 ) return 0;
421 *Phys = *ptr & ~0xFFF;
422 *Flags = *ptr & 0xFFF;
427 * \brief Get the physical address of a virtual location
429 tPAddr MM_GetPhysAddr(tVAddr Addr)
434 ret = MM_GetPageEntryPtr(Addr, 0, 0, 0, &ptr);
435 if( ret < 0 ) return 0;
437 return (*ptr & ~0xFFF) | (Addr & 0xFFF);
441 * \brief Sets the flags on a page
443 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
449 rv = MM_GetPageEntryPtr(VAddr, 0, 0, 0, &ent);
452 // Ensure the entry is valid
453 if( !(*ent & 1) ) return ;
456 if( Mask & MM_PFLAG_RO )
458 if( Flags & MM_PFLAG_RO ) {
467 if( Mask & MM_PFLAG_KERNEL )
469 if( Flags & MM_PFLAG_KERNEL ) {
478 if( Mask & MM_PFLAG_COW )
480 if( Flags & MM_PFLAG_COW ) {
491 if( Mask & MM_PFLAG_EXEC )
493 if( Flags & MM_PFLAG_EXEC ) {
503 * \brief Get the flags applied to a page
505 Uint MM_GetFlags(tVAddr VAddr)
510 rv = MM_GetPageEntryPtr(VAddr, 0, 0, 0, &ent);
513 if( !(*ent & 1) ) return 0;
516 if( !(*ent & PF_WRITE) ) ret |= MM_PFLAG_RO;
518 if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
520 if( *ent & PF_COW ) ret |= MM_PFLAG_COW;
522 if( !(*ent & PF_NX) ) ret |= MM_PFLAG_EXEC;
527 // --- Hardware Mappings ---
529 * \brief Map a range of hardware pages
531 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
536 //TODO: Add speedups (memory of first possible free)
537 for( ret = MM_HWMAP_BASE; ret < MM_HWMAP_TOP; ret += 0x1000 )
539 for( num = Number; num -- && ret < MM_HWMAP_TOP; ret += 0x1000 )
541 if( MM_GetPhysAddr(ret) != 0 ) break;
543 if( num >= 0 ) continue;
555 Log_KernelPanic("MM", "TODO: Implement MM_MapHWPages");
560 * \brief Free a range of hardware pages
562 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
564 // Log_KernelPanic("MM", "TODO: Implement MM_UnmapHWPages");
574 * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
575 * \brief Allocates DMA physical memory
576 * \param Pages Number of pages required
577 * \param MaxBits Maximum number of bits the physical address can have
578 * \param PhysAddr Pointer to the location to place the physical address allocated
579 * \return Virtual address allocate
581 tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
587 if(MaxBits < 12 || !PhysAddr) return 0;
590 if(Pages == 1 && MaxBits >= PHYS_BITS)
592 phys = MM_AllocPhys();
594 ret = MM_MapHWPages(phys, 1);
603 phys = MM_AllocPhysRange(Pages, MaxBits);
604 // - Was it allocated?
605 if(phys == 0) return 0;
607 // Allocated successfully, now map
608 ret = MM_MapHWPages(phys, Pages);
610 // If it didn't map, free then return 0
611 for(;Pages--;phys+=0x1000)
620 // --- Tempory Mappings ---
621 tVAddr MM_MapTemp(tPAddr PAddr)
623 Log_KernelPanic("MM", "TODO: Implement MM_MapTemp");
627 void MM_FreeTemp(tVAddr VAddr)
629 Log_KernelPanic("MM", "TODO: Implement MM_FreeTemp");
634 // --- Address Space Clone --
635 tPAddr MM_Clone(void)
639 // #1 Create a copy of the PML4
640 ret = MM_AllocPhys();
643 // #2 Alter the fractal pointer
644 Mutex_Acquire(&glMM_TempFractalLock);
647 INVLPG(TMPMAPLVL4(0));
648 memcpy(&TMPMAPLVL4(0), &PAGEMAPLVL4(0), 0x1000);
650 Log_KernelPanic("MM", "TODO: Implement MM_Clone");
652 // #3 Set Copy-On-Write to all user pages
655 INVLPG(TMPMAPLVL4(0));
656 Mutex_Release(&glMM_TempFractalLock);
660 void MM_ClearUser(void)
663 // #1 Traverse the structure < 2^47, Deref'ing all pages
664 // #2 Free tables/dirs/pdps once they have been cleared
666 for( addr = 0; addr < 0x800000000000; )
668 if( PAGEMAPLVL4(addr >> PML4_SHIFT) & 1 )
670 if( PAGEDIRPTR(addr >> PDP_SHIFT) & 1 )
672 if( PAGEDIR(addr >> PDIR_SHIFT) & 1 )
675 if( PAGETABLE(addr >> PTAB_SHIFT) & 1 ) {
676 MM_DerefPhys( PAGETABLE(addr >> PTAB_SHIFT) & PADDR_MASK );
677 PAGETABLE(addr >> PTAB_SHIFT) = 0;
679 addr += 1 << PTAB_SHIFT;
680 // Dereference the PDIR Entry
681 if( (addr + (1 << PTAB_SHIFT)) >> PDIR_SHIFT != (addr >> PDIR_SHIFT) ) {
682 MM_DerefPhys( PAGEMAPLVL4(addr >> PDIR_SHIFT) & PADDR_MASK );
683 PAGEDIR(addr >> PDIR_SHIFT) = 0;
687 addr += 1 << PDIR_SHIFT;
690 // Dereference the PDP Entry
691 if( (addr + (1 << PDIR_SHIFT)) >> PDP_SHIFT != (addr >> PDP_SHIFT) ) {
692 MM_DerefPhys( PAGEMAPLVL4(addr >> PDP_SHIFT) & PADDR_MASK );
693 PAGEDIRPTR(addr >> PDP_SHIFT) = 0;
697 addr += 1 << PDP_SHIFT;
700 // Dereference the PML4 Entry
701 if( (addr + (1 << PDP_SHIFT)) >> PML4_SHIFT != (addr >> PML4_SHIFT) ) {
702 MM_DerefPhys( PAGEMAPLVL4(addr >> PML4_SHIFT) & PADDR_MASK );
703 PAGEMAPLVL4(addr >> PML4_SHIFT) = 0;
707 addr += (tVAddr)1 << PML4_SHIFT;
713 tVAddr MM_NewWorkerStack(void)
718 Log_KernelPanic("MM", "TODO: Implement MM_NewWorkerStack");
720 // #1 Set temp fractal to PID0
721 Mutex_Acquire(&glMM_TempFractalLock);
722 TMPCR3() = ((tPAddr)gInitialPML4 - KERNEL_BASE) | 3;
724 // #2 Scan for a free stack addresss < 2^47
725 for(ret = 0x100000; ret < (1ULL << 47); ret += KERNEL_STACK_SIZE)
727 if( MM_GetPhysAddr(ret) == 0 ) break;
729 if( ret >= (1ULL << 47) ) {
730 Mutex_Release(&glMM_TempFractalLock);
734 // #3 Map all save the last page in the range
735 // - This acts as as guard page, and doesn't cost us anything.
736 for( i = 0; i < KERNEL_STACK_SIZE/0x1000 - 1; i ++ )
741 Mutex_Release(&glMM_TempFractalLock);
747 * \brief Allocate a new kernel stack
749 tVAddr MM_NewKStack(void)
751 tVAddr base = MM_KSTACK_BASE;
753 for( ; base < MM_KSTACK_TOP; base += KERNEL_STACK_SIZE )
755 if(MM_GetPhysAddr(base) != 0)
758 //Log("MM_NewKStack: Found one at %p", base + KERNEL_STACK_SIZE);
759 for( i = 0; i < KERNEL_STACK_SIZE; i += 0x1000)
761 if( !MM_Allocate(base+i) )
763 Log_Warning("MM", "MM_NewKStack - Allocation failed");
764 for( i -= 0x1000; i; i -= 0x1000)
765 MM_Deallocate(base+i);
770 return base + KERNEL_STACK_SIZE;
772 Log_Warning("MM", "MM_NewKStack - No address space left\n");