4 * Virtual Memory Manager
17 #define PADDR_MASK 0x7FFFFFFF##FFFFF000
18 #define PAGE_MASK (((Uint)1 << 36)-1)
19 #define TABLE_MASK (((Uint)1 << 27)-1)
20 #define PDP_MASK (((Uint)1 << 18)-1)
21 #define PML4_MASK (((Uint)1 << 9)-1)
23 #define PF_PRESENT 0x1
27 #define PF_PAGED 0x400
28 #define PF_NX 0x80000000##00000000
31 #define PAGETABLE(idx) (*((tPAddr*)MM_FRACTAL_BASE+((idx)&PAGE_MASK)))
32 #define PAGEDIR(idx) PAGETABLE((MM_FRACTAL_BASE>>12)+((idx)&TABLE_MASK))
33 #define PAGEDIRPTR(idx) PAGEDIR((MM_FRACTAL_BASE>>21)+((idx)&PDP_MASK))
34 #define PAGEMAPLVL4(idx) PAGEDIRPTR((MM_FRACTAL_BASE>>30)+((idx)&PML4_MASK))
36 #define INVLPG(__addr) __asm__ __volatile__ ("invlpg (%0)"::"r"(__addr));
39 void MM_InitVirt(void);
40 void MM_FinishVirtualInit(void);
41 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
42 void MM_DumpTables(tVAddr Start, tVAddr End);
43 int MM_Map(tVAddr VAddr, tPAddr PAddr);
48 void MM_InitVirt(void)
52 void MM_FinishVirtualInit(void)
57 * \brief Called on a page fault
59 void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
61 // TODO: Copy on Write
63 if( gaPageDir [Addr>>22] & PF_PRESENT
64 && gaPageTable[Addr>>12] & PF_PRESENT
65 && gaPageTable[Addr>>12] & PF_COW )
68 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
70 gaPageTable[Addr>>12] &= ~PF_COW;
71 gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
75 //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
76 paddr = MM_DuplicatePage( Addr );
77 MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
78 gaPageTable[Addr>>12] &= PF_USER;
79 gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
82 INVLPG( Addr & ~0xFFF );
87 // If it was a user, tell the thread handler
89 Warning("%s %s %s memory%s",
90 (ErrorCode&4?"User":"Kernel"),
91 (ErrorCode&2?"write to":"read from"),
92 (ErrorCode&1?"bad/locked":"non-present"),
93 (ErrorCode&16?" (Instruction Fetch)":"")
95 Warning("User Pagefault: Instruction at %04x:%08x accessed %p",
96 Regs->CS, Regs->RIP, Addr);
97 __asm__ __volatile__ ("sti"); // Restart IRQs
98 // Threads_SegFault(Addr);
104 // -- Check Error Code --
106 Warning("Reserved Bits Trashed!");
109 Warning("%s %s %s memory%s",
110 (ErrorCode&4?"User":"Kernel"),
111 (ErrorCode&2?"write to":"read from"),
112 (ErrorCode&1?"bad/locked":"non-present"),
113 (ErrorCode&16?" (Instruction Fetch)":"")
117 Log("Code at %p accessed %p", Regs->RIP, Addr);
118 // Print Stack Backtrace
119 // Error_Backtrace(Regs->RIP, Regs->RBP);
121 MM_DumpTables(0, -1);
123 __asm__ __volatile__ ("cli");
129 * \brief Dumps the layout of the page tables
131 void MM_DumpTables(tVAddr Start, tVAddr End)
133 const tPAddr CHANGEABLE_BITS = 0xFF8;
134 const tPAddr MASK = ~CHANGEABLE_BITS; // Physical address and access bits
135 tVAddr rangeStart = 0;
136 tPAddr expected = CHANGEABLE_BITS; // MASK is used because it's not a vaild value
140 End &= (1L << 48) - 1;
142 Start >>= 12; End >>= 12;
144 Log("Table Entries:");
145 for(page = Start, curPos = Start<<12;
147 curPos += 0x1000, page++)
149 if( curPos == 0x800000000000L )
150 curPos = 0xFFFF800000000000L;
154 !(PAGEMAPLVL4(page>>27) & PF_PRESENT)
155 || !(PAGEDIRPTR(page>>18) & PF_PRESENT)
156 || !(PAGEDIR(page>>9) & PF_PRESENT)
157 || !(PAGETABLE(page) & PF_PRESENT)
158 || (PAGETABLE(page) & MASK) != expected)
160 if(expected != CHANGEABLE_BITS) {
161 Log("%016x-0x%016x => %013x-%013x (%c%c%c%c)",
162 rangeStart, curPos - 1,
163 PAGETABLE(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' : '-')
170 expected = CHANGEABLE_BITS;
172 if( !(PAGEMAPLVL4(page>>27) & PF_PRESENT) ) {
173 page += (1 << 27) - 1;
174 curPos += (1L << 39) - 0x1000;
177 if( !(PAGEDIRPTR(page>>18) & PF_PRESENT) ) {
178 page += (1 << 18) - 1;
179 curPos += (1L << 30) - 0x1000;
182 if( !(PAGEDIR(page>>9) & PF_PRESENT) ) {
183 page += (1 << 9) - 1;
184 curPos += (1L << 21) - 0x1000;
187 if( !(PAGETABLE(page) & PF_PRESENT) ) continue;
189 expected = (PAGETABLE(page) & MASK);
192 if(expected != CHANGEABLE_BITS)
196 if(expected != CHANGEABLE_BITS) {
197 Log("%016x-%016x => %013x-%013x (%s%s%s%s)",
198 rangeStart, curPos - 1,
199 PAGETABLE(rangeStart>>12) & ~0xFFF,
200 (expected & ~0xFFF) - 1,
201 (expected & PF_PAGED ? "p" : "-"),
202 (expected & PF_COW ? "C" : "-"),
203 (expected & PF_USER ? "U" : "-"),
204 (expected & PF_WRITE ? "W" : "-")
211 * \brief Map a physical page to a virtual one
213 int MM_Map(tVAddr VAddr, tPAddr PAddr)
217 ENTER("xVAddr xPAddr", VAddr, PAddr);
220 //Log(" MM_Map: &PAGEMAPLVL4(%x) = %x", VAddr >> 39, &PAGEMAPLVL4(VAddr >> 39));
221 //Log(" MM_Map: &PAGEDIRPTR(%x) = %x", VAddr >> 30, &PAGEDIRPTR(VAddr >> 30));
222 //Log(" MM_Map: &PAGEDIR(%x) = %x", VAddr >> 21, &PAGEDIR(VAddr >> 21));
223 //Log(" MM_Map: &PAGETABLE(%x) = %x", VAddr >> 12, &PAGETABLE(VAddr >> 12));
224 //Log(" MM_Map: &PAGETABLE(0) = %x", &PAGETABLE(0));
225 if( !(PAGEMAPLVL4(VAddr >> 39) & 1) )
227 tmp = MM_AllocPhys();
229 PAGEMAPLVL4(VAddr >> 39) = tmp | 3;
230 INVLPG( &PAGEDIRPTR( (VAddr>>39)<<9 ) );
231 memset( &PAGEDIRPTR( (VAddr>>39)<<9 ), 0, 4096 );
235 if( !(PAGEDIRPTR(VAddr >> 30) & 1) )
237 tmp = MM_AllocPhys();
239 PAGEDIRPTR(VAddr >> 30) = tmp | 3;
240 INVLPG( &PAGEDIR( (VAddr>>30)<<9 ) );
241 memset( &PAGEDIR( (VAddr>>30)<<9 ), 0, 0x1000 );
245 if( !(PAGEDIR(VAddr >> 21) & 1) )
247 tmp = MM_AllocPhys();
249 PAGEDIR(VAddr >> 21) = tmp | 3;
250 INVLPG( &PAGETABLE( (VAddr>>21)<<9 ) );
251 memset( &PAGETABLE( (VAddr>>21)<<9 ), 0, 4096 );
254 // Check if this virtual address is already mapped
255 if( PAGETABLE(VAddr >> PTAB_SHIFT) & 1 )
258 PAGETABLE(VAddr >> PTAB_SHIFT) = PAddr | 3;
267 * \brief Removed a mapped page
269 void MM_Unmap(tVAddr VAddr)
272 if( !(PAGEMAPLVL4(VAddr >> 39) & 1) ) return ;
274 if( !(PAGEDIRPTR(VAddr >> 30) & 1) ) return ;
276 if( !(PAGEDIR(VAddr >> 21) & 1) ) return ;
278 PAGETABLE(VAddr >> PTAB_SHIFT) = 0;
283 * \brief Allocate a block of memory at the specified virtual address
285 tPAddr MM_Allocate(tVAddr VAddr)
289 ENTER("xVAddr", VAddr);
291 // NOTE: This is hack, but I like my dumps to be neat
293 if( !MM_Map(VAddr, 0) ) // Make sure things are allocated
295 Warning("MM_Allocate: Unable to map, tables did not initialise");
302 ret = MM_AllocPhys();
303 LOG("ret = %x", ret);
309 if( !MM_Map(VAddr, ret) )
311 Warning("MM_Allocate: Unable to map. Strange, we should have errored earlier");
321 void MM_Deallocate(tVAddr VAddr)
325 phys = MM_GetPhysAddr(VAddr);
334 * \brief Get the physical address of a virtual location
336 tPAddr MM_GetPhysAddr(tVAddr Addr)
338 Log("MM_GetPhysAddr: (Addr=0x%x)", Addr);
339 if( !(PAGEMAPLVL4(Addr >> 39) & 1) )
341 Log(" MM_GetPhysAddr: PDP Valid");
342 if( !(PAGEDIRPTR(Addr >> 30) & 1) )
344 Log(" MM_GetPhysAddr: PD Valid");
345 if( !(PAGEDIR(Addr >> 21) & 1) )
347 Log(" MM_GetPhysAddr: PT Valid");
348 if( !(PAGETABLE(Addr >> PTAB_SHIFT) & 1) )
350 Log(" MM_GetPhysAddr: Page Valid");
352 return (PAGETABLE(Addr >> PTAB_SHIFT) & ~0xFFF) | (Addr & 0xFFF);
356 * \brief Sets the flags on a page
358 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
363 if( !(PAGEMAPLVL4(VAddr >> 39) & 1) )
365 if( !(PAGEDIRPTR(VAddr >> 30) & 1) )
367 if( !(PAGEDIR(VAddr >> 21) & 1) )
369 if( !(PAGETABLE(VAddr >> 12) & 1) )
373 ent = &PAGETABLE(VAddr >> 12);
376 if( Mask & MM_PFLAG_RO )
378 if( Flags & MM_PFLAG_RO ) {
387 if( Mask & MM_PFLAG_KERNEL )
389 if( Flags & MM_PFLAG_KERNEL ) {
398 if( Mask & MM_PFLAG_COW )
400 if( Flags & MM_PFLAG_COW ) {
411 if( Mask & MM_PFLAG_EXEC )
413 if( Flags & MM_PFLAG_EXEC ) {
423 * \brief Get the flags applied to a page
425 Uint MM_GetFlags(tVAddr VAddr)
431 if( !(PAGEMAPLVL4(VAddr >> 39) & 1) )
433 if( !(PAGEDIRPTR(VAddr >> 30) & 1) )
435 if( !(PAGEDIR(VAddr >> 21) & 1) )
437 if( !(PAGETABLE(VAddr >> 12) & 1) )
441 ent = &PAGETABLE(VAddr >> 12);
444 if( !(*ent & PF_WRITE) ) ret |= MM_PFLAG_RO;
446 if( !(*ent & PF_USER) ) ret |= MM_PFLAG_KERNEL;
448 if( *ent & PF_COW ) ret |= MM_PFLAG_COW;
450 if( !(*ent & PF_NX) ) ret |= MM_PFLAG_EXEC;
455 // --- Hardware Mappings ---
457 * \brief Map a range of hardware pages
459 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
461 Log_KernelPanic("MM", "TODO: Implement MM_MapHWPages");
466 * \brief Free a range of hardware pages
468 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
470 Log_KernelPanic("MM", "TODO: Implement MM_UnmapHWPages");
473 // --- Tempory Mappings ---
474 tVAddr MM_MapTemp(tPAddr PAddr)
476 Log_KernelPanic("MM", "TODO: Implement MM_MapTemp");
480 void MM_FreeTemp(tVAddr VAddr)
482 Log_KernelPanic("MM", "TODO: Implement MM_FreeTemp");
487 // --- Address Space Clone --
488 tPAddr MM_Clone(void)
492 // #1 Create a copy of the PML4
493 ret = MM_AllocPhys();
496 Log_KernelPanic("MM", "TODO: Implement MM_Clone");
498 // #2 Alter the fractal pointer
499 // #3 Set Copy-On-Write to all user pages
504 void MM_ClearUser(void)
507 // #1 Traverse the structure < 2^47, Deref'ing all pages
508 // #2 Free tables/dirs/pdps once they have been cleared
510 for( addr = 0; addr < 0x800000000000; )
512 if( PAGEMAPLVL4(addr >> PML4_SHIFT) & 1 )
514 if( PAGEDIRPTR(addr >> PDP_SHIFT) & 1 )
516 if( PAGEDIR(addr >> PDIR_SHIFT) & 1 )
519 if( PAGETABLE(addr >> PTAB_SHIFT) & 1 ) {
520 MM_DerefPhys( PAGETABLE(addr >> PTAB_SHIFT) & PADDR_MASK );
521 PAGETABLE(addr >> PTAB_SHIFT) = 0;
523 addr += 1 << PTAB_SHIFT;
524 // Dereference the PDIR Entry
525 if( (addr + (1 << PTAB_SHIFT)) >> PDIR_SHIFT != (addr >> PDIR_SHIFT) ) {
526 MM_DerefPhys( PAGEMAPLVL4(addr >> PDIR_SHIFT) & PADDR_MASK );
527 PAGEDIR(addr >> PDIR_SHIFT) = 0;
531 addr += 1 << PDIR_SHIFT;
534 // Dereference the PDP Entry
535 if( (addr + (1 << PDIR_SHIFT)) >> PDP_SHIFT != (addr >> PDP_SHIFT) ) {
536 MM_DerefPhys( PAGEMAPLVL4(addr >> PDP_SHIFT) & PADDR_MASK );
537 PAGEDIRPTR(addr >> PDP_SHIFT) = 0;
541 addr += 1 << PDP_SHIFT;
544 // Dereference the PML4 Entry
545 if( (addr + (1 << PDP_SHIFT)) >> PML4_SHIFT != (addr >> PML4_SHIFT) ) {
546 MM_DerefPhys( PAGEMAPLVL4(addr >> PML4_SHIFT) & PADDR_MASK );
547 PAGEMAPLVL4(addr >> PML4_SHIFT) = 0;
551 addr += (tVAddr)1 << PML4_SHIFT;
557 tVAddr MM_NewWorkerStack(void)
559 Log_KernelPanic("MM", "TODO: Implement MM_NewWorkerStack");
564 * \brief Allocate a new kernel stack
566 tVAddr MM_NewKStack(void)
568 tVAddr base = MM_KSTACK_BASE;
570 for( ; base < MM_KSTACK_TOP; base += KERNEL_STACK_SIZE )
572 if(MM_GetPhysAddr(base) != 0)
575 Log("MM_NewKStack: Found one at %p", base + KERNEL_STACK_SIZE);
576 for( i = 0; i < KERNEL_STACK_SIZE; i += 0x1000)
579 return base + KERNEL_STACK_SIZE;
581 Log_Warning("MM", "MM_NewKStack - No address space left\n");