X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Farch%2Fx86_64%2Fmm_virt.c;h=c04fcf3a359216ea57d8fa76f48a5eac165fe79e;hb=463074dd4899f1cc851bff9c74356f5c6def1bb2;hp=4cce485418ca7727550df12eb88ebc07487ab9ee;hpb=9f407c493c33928e0f19b834699d9694036ca42e;p=tpg%2Facess2.git

diff --git a/Kernel/arch/x86_64/mm_virt.c b/Kernel/arch/x86_64/mm_virt.c
index 4cce4854..c04fcf3a 100644
--- a/Kernel/arch/x86_64/mm_virt.c
+++ b/Kernel/arch/x86_64/mm_virt.c
@@ -3,79 +3,451 @@
  * 
  * Virtual Memory Manager
  */
+#define DEBUG	0
 #include <acess.h>
 #include <mm_virt.h>
+#include <threads_int.h>
+#include <proc.h>
 
 // === CONSTANTS ===
+#define PHYS_BITS	52	// TODO: Move out
+#define VIRT_BITS	48
+
 #define PML4_SHIFT	39
 #define PDP_SHIFT	30
 #define PDIR_SHIFT	21
 #define PTAB_SHIFT	12
 
-#define	PF_PRESENT	0x1
-#define	PF_WRITE	0x2
-#define	PF_USER		0x4
-#define	PF_NX		0x80000000##00000000
+#define	PADDR_MASK	0x7FFFFFFF##FFFFF000
+#define PAGE_MASK	((1LL << 36)-1)
+#define TABLE_MASK	((1LL << 27)-1)
+#define PDP_MASK	((1LL << 18)-1)
+#define PML4_MASK	((1LL << 9)-1)
+
+#define	PF_PRESENT	0x001
+#define	PF_WRITE	0x002
+#define	PF_USER		0x004
+#define	PF_LARGE	0x080
+#define	PF_GLOBAL	0x100
 #define	PF_COW		0x200
 #define	PF_PAGED	0x400
+#define	PF_NX		0x80000000##00000000
 
 // === MACROS ===
-#define PAGETABLE(idx)	(*((tPAddr*)MM_FRACTAL_BASE+(idx)))
-#define PAGEDIR(idx)	PAGETABLE((MM_FRACTAL_BASE>>12)+((idx)&0x7FFFFFF))
-#define PAGEDIRPTR(idx)	PAGETABLE((MM_FRACTAL_BASE>>21)+((idx)&0x3FFFF))
-#define PAGEMAPLVL4(idx)	PAGETABLE((MM_FRACTAL_BASE>>30)+((idx)&0x1FF))
+#define PAGETABLE(idx)	(*((Uint64*)MM_FRACTAL_BASE+((idx)&PAGE_MASK)))
+#define PAGEDIR(idx)	PAGETABLE((MM_FRACTAL_BASE>>12)+((idx)&TABLE_MASK))
+#define PAGEDIRPTR(idx)	PAGEDIR((MM_FRACTAL_BASE>>21)+((idx)&PDP_MASK))
+#define PAGEMAPLVL4(idx)	PAGEDIRPTR((MM_FRACTAL_BASE>>30)+((idx)&PML4_MASK))
+
+#define TMPCR3()	PAGEMAPLVL4(MM_TMPFRAC_BASE>>39)
+#define TMPTABLE(idx)	(*((Uint64*)MM_TMPFRAC_BASE+((idx)&PAGE_MASK)))
+#define TMPDIR(idx)	PAGETABLE((MM_TMPFRAC_BASE>>12)+((idx)&TABLE_MASK))
+#define TMPDIRPTR(idx)	PAGEDIR((MM_TMPFRAC_BASE>>21)+((idx)&PDP_MASK))
+#define TMPMAPLVL4(idx)	PAGEDIRPTR((MM_TMPFRAC_BASE>>30)+((idx)&PML4_MASK))
+
+#define INVLPG(__addr)	__asm__ __volatile__ ("invlpg (%0)"::"r"(__addr))
+#define INVLPG_ALL()	__asm__ __volatile__ ("mov %cr3,%rax;\n\tmov %rax,%cr3;")
+#define INVLPG_GLOBAL()	__asm__ __volatile__ ("mov %cr4,%rax;\n\txorl $0x80, %eax;\n\tmov %rax,%cr4;\n\txorl $0x80, %eax;\n\tmov %rax,%cr4")
+
+// === CONSTS ===
+//tPAddr	* const gaPageTable = MM_FRACTAL_BASE;
+
+// === IMPORTS ===
+extern void	Error_Backtrace(Uint IP, Uint BP);
+extern tPAddr	gInitialPML4[512];
+extern void	Threads_SegFault(tVAddr Addr);
+extern char	_UsertextBase[];
+
+// === PROTOTYPES ===
+void	MM_InitVirt(void);
+//void	MM_FinishVirtualInit(void);
+void	MM_int_ClonePageEnt( Uint64 *Ent, void *NextLevel, tVAddr Addr, int bTable );
+ int	MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
+void	MM_int_DumpTablesEnt(tVAddr RangeStart, size_t Length, tPAddr Expected);
+void	MM_DumpTables(tVAddr Start, tVAddr End);
+ int	MM_GetPageEntryPtr(tVAddr Addr, BOOL bTemp, BOOL bAllocate, BOOL bLargePage, tPAddr **Pointer);
+ int	MM_MapEx(tVAddr VAddr, tPAddr PAddr, BOOL bTemp, BOOL bLarge);
+// int	MM_Map(tVAddr VAddr, tPAddr PAddr);
+void	MM_Unmap(tVAddr VAddr);
+void	MM_int_ClearTableLevel(tVAddr VAddr, int LevelBits, int MaxEnts);
+void	MM_ClearUser(void);
+ int	MM_GetPageEntry(tVAddr Addr, tPAddr *Phys, Uint *Flags);
 
 // === GLOBALS ===
+tMutex	glMM_TempFractalLock;
+tPAddr	gMM_ZeroPage;
 
 // === CODE ===
 void MM_InitVirt(void)
 {
+//	Log_Debug("MMVirt", "&PAGEMAPLVL4(0) = %p", &PAGEMAPLVL4(0));
+//	MM_DumpTables(0, -1L);
+}
+
+void MM_FinishVirtualInit(void)
+{
+	PAGEMAPLVL4(0) = 0;
+}
+
+/**
+ * \brief Clone a page from an entry
+ * \param Ent	Pointer to the entry in the PML4/PDP/PD/PT
+ * \param NextLevel	Pointer to contents of the entry
+ * \param Addr	Dest address
+ * \note Used in COW
+ */
+void MM_int_ClonePageEnt( Uint64 *Ent, void *NextLevel, tVAddr Addr, int bTable )
+{
+	tPAddr	curpage = *Ent & PADDR_MASK; 
+	if( MM_GetRefCount( curpage ) <= 0 ) {
+		Log_KernelPanic("MMVirt", "Page %P still marked COW, but unreferenced", curpage);
+	}
+	if( MM_GetRefCount( curpage ) == 1 )
+	{
+		*Ent &= ~PF_COW;
+		*Ent |= PF_PRESENT|PF_WRITE;
+//		Log_Debug("MMVirt", "COW ent at %p (%p) only %P", Ent, NextLevel, curpage);
+	}
+	else
+	{
+		void	*tmp;
+		tPAddr	paddr;
+		
+		if( !(paddr = MM_AllocPhys()) ) {
+			Threads_SegFault(Addr);
+			return ;
+		}
+
+		ASSERT(paddr != curpage);
+			
+		tmp = (void*)MM_MapTemp(paddr);
+		memcpy( tmp, NextLevel, 0x1000 );
+		MM_FreeTemp( (tVAddr)tmp );
+		
+//		Log_Debug("MMVirt", "COW ent at %p (%p) from %P to %P", Ent, NextLevel, curpage, paddr);
+
+		MM_DerefPhys( curpage );
+		*Ent &= PF_USER;
+		*Ent |= paddr|PF_PRESENT|PF_WRITE;
+	}
+	INVLPG( (tVAddr)NextLevel );
 	
+	// Mark COW on pages
+	if(bTable) 
+	{
+		Uint64	*dp = NextLevel;
+		 int	i;
+		for( i = 0; i < 512; i ++ )
+		{
+			if( !(dp[i] & PF_PRESENT) )	continue;
+			MM_RefPhys( dp[i] & PADDR_MASK );
+			if( dp[i] & PF_WRITE ) {
+				dp[i] &= ~PF_WRITE;
+				dp[i] |= PF_COW;
+			}
+		}
+	}
+}
+
+/*
+ * \brief Called on a page fault
+ */
+int MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
+{
+	// TODO: Implement Copy-on-Write
+	#if 1
+	if( PAGEMAPLVL4(Addr>>39) & PF_PRESENT
+	 && PAGEDIRPTR (Addr>>30) & PF_PRESENT
+	 && PAGEDIR    (Addr>>21) & PF_PRESENT
+	 && PAGETABLE  (Addr>>12) & PF_PRESENT )
+	{
+		// PML4 Entry
+		if( PAGEMAPLVL4(Addr>>39) & PF_COW )
+		{
+			tPAddr	*dp = &PAGEDIRPTR((Addr>>39)*512);
+			MM_int_ClonePageEnt( &PAGEMAPLVL4(Addr>>39), dp, Addr, 1 );
+//			MM_DumpTables(Addr>>39 << 39, (((Addr>>39) + 1) << 39) - 1);
+		}
+		// PDP Entry
+		if( PAGEDIRPTR(Addr>>30) & PF_COW )
+		{
+			tPAddr	*dp = &PAGEDIR( (Addr>>30)*512 );
+			MM_int_ClonePageEnt( &PAGEDIRPTR(Addr>>30), dp, Addr, 1 );
+//			MM_DumpTables(Addr>>30 << 30, (((Addr>>30) + 1) << 30) - 1);
+		}
+		// PD Entry
+		if( PAGEDIR(Addr>>21) & PF_COW )
+		{
+			tPAddr	*dp = &PAGETABLE( (Addr>>21)*512 );
+			MM_int_ClonePageEnt( &PAGEDIR(Addr>>21), dp, Addr, 1 );
+//			MM_DumpTables(Addr>>21 << 21, (((Addr>>21) + 1) << 21) - 1);
+		}
+		// PT Entry
+		if( PAGETABLE(Addr>>12) & PF_COW )
+		{
+			MM_int_ClonePageEnt( &PAGETABLE(Addr>>12), (void*)(Addr & ~0xFFF), Addr, 0 );
+			INVLPG( Addr & ~0xFFF );
+			return 0;
+		}
+	}
+	#endif
+	
+	// If it was a user, tell the thread handler
+	if(ErrorCode & 4) {
+		Warning("User %s %s memory%s",
+			(ErrorCode&2?"write to":"read from"),
+			(ErrorCode&1?"bad/locked":"non-present"),
+			(ErrorCode&16?" (Instruction Fetch)":"")
+			);
+		Warning("User Pagefault: Instruction at %04x:%p accessed %p",
+			Regs->CS, Regs->RIP, Addr);
+		__asm__ __volatile__ ("sti");	// Restart IRQs
+		Error_Backtrace(Regs->RIP, Regs->RBP);
+		Threads_SegFault(Addr);
+		return 0;
+	}
+	
+	// Kernel #PF
+	Debug_KernelPanic();
+	// -- Check Error Code --
+	if(ErrorCode & 8)
+		Warning("Reserved Bits Trashed!");
+	else
+	{
+		Warning("Kernel %s %s memory%s",
+			(ErrorCode&2?"write to":"read from"),
+			(ErrorCode&1?"bad/locked":"non-present"),
+			(ErrorCode&16?" (Instruction Fetch)":"")
+			);
+	}
+	
+	Log("Thread %i - Code at %p accessed %p", Threads_GetTID(), Regs->RIP, Addr);
+	// Print Stack Backtrace
+	Error_Backtrace(Regs->RIP, Regs->RBP);
+	
+	MM_DumpTables(0, -1);
+
+	return 1;	
+}
+
+void MM_int_DumpTablesEnt(tVAddr RangeStart, size_t Length, tPAddr Expected)
+{
+	#define CANOICAL(addr)	((addr)&0x800000000000?(addr)|0xFFFF000000000000:(addr))
+	LogF("%016llx => ", CANOICAL(RangeStart));
+//	LogF("%6llx %6llx %6llx %016llx => ",
+//		MM_GetPhysAddr( (tVAddr)&PAGEDIRPTR(RangeStart>>30) ),
+//		MM_GetPhysAddr( (tVAddr)&PAGEDIR(RangeStart>>21) ),
+//		MM_GetPhysAddr( (tVAddr)&PAGETABLE(RangeStart>>12) ),
+//		CANOICAL(RangeStart)
+//		);
+	if( gMM_ZeroPage && (PAGETABLE(RangeStart>>12) & PADDR_MASK) == gMM_ZeroPage )
+		LogF("%13s", "zero" );
+	else
+		LogF("%13llx", PAGETABLE(RangeStart>>12) & PADDR_MASK );
+	LogF(" : 0x%6llx (%c%c%c%c)\r\n",
+		Length,
+		(Expected & PF_PAGED ? 'p' : '-'),
+		(Expected & PF_COW ? 'C' : '-'),
+		(Expected & PF_USER ? 'U' : '-'),
+		(Expected & PF_WRITE ? 'W' : '-')
+		);
+	#undef CANOICAL
 }
 
 /**
- * \brief Map a physical page to a virtual one
+ * \brief Dumps the layout of the page tables
  */
-int MM_Map(tVAddr VAddr, tPAddr PAddr)
+void MM_DumpTables(tVAddr Start, tVAddr End)
 {
-	tPAddr	tmp;
+	const tPAddr	CHANGEABLE_BITS = ~(PF_PRESENT|PF_WRITE|PF_USER|PF_COW|PF_PAGED) & 0xFFF;
+	const tPAddr	MASK = ~CHANGEABLE_BITS;	// Physical address and access bits
+	tVAddr	rangeStart = 0;
+	tPAddr	expected = CHANGEABLE_BITS;	// CHANGEABLE_BITS is used because it's not a vaild value
+	tVAddr	curPos;
+	Uint	page;
 	
-	// Check PML4
-	if( !(PAGEMAPLVL4(VAddr >> 39) & 1) )
+	Log("Table Entries: (%p to %p)", Start, End);
+	
+	End &= (1L << 48) - 1;
+	
+	Start >>= 12;	End >>= 12;
+	
+	for(page = Start, curPos = Start<<12;
+		page < End;
+		curPos += 0x1000, page++)
 	{
-		tmp = MM_AllocPhys();
-		if(!tmp)	return 0;
-		PAGEMAPLVL4(VAddr >> 39) = tmp | 3;
-		memset( &PAGEDIRPTR( (VAddr>>39)<<9 ), 0, 4096 );
+		//Debug("&PAGEMAPLVL4(%i page>>27) = %p", page>>27, &PAGEMAPLVL4(page>>27));
+		//Debug("&PAGEDIRPTR(%i page>>18) = %p", page>>18, &PAGEDIRPTR(page>>18));
+		//Debug("&PAGEDIR(%i page>>9) = %p", page>>9, &PAGEDIR(page>>9));
+		//Debug("&PAGETABLE(%i page) = %p", page, &PAGETABLE(page));
+		
+		// End of a range
+		if(!(PAGEMAPLVL4(page>>27) & PF_PRESENT)
+		|| !(PAGEDIRPTR(page>>18) & PF_PRESENT)
+		|| !(PAGEDIR(page>>9) & PF_PRESENT)
+		|| !(PAGETABLE(page) & PF_PRESENT)
+		|| (PAGETABLE(page) & MASK) != expected)
+		{			
+			if(expected != CHANGEABLE_BITS)
+			{
+				MM_int_DumpTablesEnt( rangeStart, curPos - rangeStart, expected );
+				expected = CHANGEABLE_BITS;
+			}
+			
+			if( curPos == 0x800000000000L )
+				curPos = 0xFFFF800000000000L;
+		
+			if( !(PAGEMAPLVL4(page>>27) & PF_PRESENT) ) {
+				page += (1 << 27) - 1;
+				curPos += (1L << 39) - 0x1000;
+				continue;
+			}
+			if( !(PAGEDIRPTR(page>>18) & PF_PRESENT) ) {
+				page += (1 << 18) - 1;
+				curPos += (1L << 30) - 0x1000;
+				continue;
+			}
+			if( !(PAGEDIR(page>>9) & PF_PRESENT) ) {
+				page += (1 << 9) - 1;
+				curPos += (1L << 21) - 0x1000;
+				continue;
+			}
+			if( !(PAGETABLE(page) & PF_PRESENT) )	continue;
+			
+			expected = (PAGETABLE(page) & MASK);
+			rangeStart = curPos;
+		}
+		if(gMM_ZeroPage && (expected & PADDR_MASK) == gMM_ZeroPage )
+			expected = expected;
+		else if(expected != CHANGEABLE_BITS)
+			expected += 0x1000;
 	}
 	
-	// Check PDP
-	if( !(PAGEDIRPTR(VAddr >> 30) & 1) )
+	if(expected != CHANGEABLE_BITS) {
+		MM_int_DumpTablesEnt( rangeStart, curPos - rangeStart, expected );
+		expected = 0;
+	}
+}
+
+/**
+ * \brief Get a pointer to a page entry
+ * \param Addr	Virtual Address
+ * \param bTemp	Use the Temporary fractal mapping
+ * \param bAllocate	Allocate entries
+ * \param bLargePage	Request a large page
+ * \param Pointer	Location to place the calculated pointer
+ * \return Page size, or -ve on error
+ */
+int MM_GetPageEntryPtr(tVAddr Addr, BOOL bTemp, BOOL bAllocate, BOOL bLargePage, tPAddr **Pointer)
+{
+	tPAddr	*pmlevels[4];
+	tPAddr	tmp;
+	 int	i, size;
+	
+	#define BITMASK(bits)	( (1LL << (bits))-1 )
+
+	if( bTemp )
 	{
-		tmp = MM_AllocPhys();
-		if(!tmp)	return 0;
-		PAGEDIRPTR(VAddr >> 30) = tmp | 3;
-		memset( &PAGEDIR( (VAddr>>30)<<9 ), 0, 4096 );
+		pmlevels[3] = &TMPTABLE(0);	// Page Table
+		pmlevels[2] = &TMPDIR(0);	// PDIR
+		pmlevels[1] = &TMPDIRPTR(0);	// PDPT
+		pmlevels[0] = &TMPMAPLVL4(0);	// PML4
+	}
+	else
+	{
+		pmlevels[3] = (void*)MM_FRACTAL_BASE;	// Page Table
+		pmlevels[2] = &pmlevels[3][(MM_FRACTAL_BASE>>12)&BITMASK(VIRT_BITS-12)];	// PDIR
+		pmlevels[1] = &pmlevels[2][(MM_FRACTAL_BASE>>21)&BITMASK(VIRT_BITS-21)];	// PDPT
+		pmlevels[0] = &pmlevels[1][(MM_FRACTAL_BASE>>30)&BITMASK(VIRT_BITS-30)];	// PML4
 	}
 	
-	// Check Page Dir
-	if( !(PAGEDIR(VAddr >> 21) & 1) )
+	// Mask address
+	Addr &= (1ULL << 48)-1;
+	
+	for( size = 39, i = 0; size > 12; size -= 9, i ++ )
 	{
-		tmp = MM_AllocPhys();
-		if(!tmp)	return 0;
-		PAGEDIR(VAddr >> 21) = tmp | 3;
-		memset( &PAGETABLE( (VAddr>>21)<<9 ), 0, 4096 );
+		Uint64	*ent = &pmlevels[i][Addr >> size];
+//		INVLPG( &pmlevels[i][ (Addr >> ADDR_SIZES[i]) & 
+		
+		// Check for a free large page slot
+		// TODO: Better support with selectable levels
+		if( (Addr & ((1ULL << size)-1)) == 0 && bLargePage )
+		{
+			if(Pointer)	*Pointer = ent;
+			return size;
+		}
+		// Allocate an entry if required
+		if( !(*ent & PF_PRESENT) )
+		{
+			if( !bAllocate )	return -4;	// If allocation is not requested, error
+			if( !(tmp = MM_AllocPhys()) )	return -2;
+			*ent = tmp | 3;
+			if( Addr < 0x800000000000 )
+				*ent |= PF_USER;
+			INVLPG( &pmlevels[i+1][ (Addr>>size)*512 ] );
+			memset( &pmlevels[i+1][ (Addr>>size)*512 ], 0, 0x1000 );
+			LOG("Init PML%i ent 0x%x %p with %P", 4 - i,
+				Addr>>size, (Addr>>size) << size, tmp);
+		}
+		// Catch large pages
+		else if( *ent & PF_LARGE )
+		{
+			// Alignment
+			if( (Addr & ((1ULL << size)-1)) != 0 )	return -3;
+			if(Pointer)	*Pointer = ent;
+			return size;	// Large page warning
+		}
 	}
 	
-	// Check if this virtual address is already mapped
-	if( PAGETABLE(VAddr >> 12) & 1 )
-		return 0;
+	// And, set the page table entry
+	if(Pointer)	*Pointer = &pmlevels[i][Addr >> size];
+	return size;
+}
+
+/**
+ * \brief Map a physical page to a virtual one
+ * \param VAddr	Target virtual address
+ * \param PAddr	Physical address of page
+ * \param bTemp	Use tempoary mappings
+ * \param bLarge	Treat as a large page
+ */
+int MM_MapEx(tVAddr VAddr, tPAddr PAddr, BOOL bTemp, BOOL bLarge)
+{
+	tPAddr	*ent;
+	 int	rv;
+	
+	ENTER("pVAddr PPAddr", VAddr, PAddr);
+	
+	// Get page pointer (Allow allocating)
+	rv = MM_GetPageEntryPtr(VAddr, bTemp, 1, bLarge, &ent);
+	if(rv < 0)	LEAVE_RET('i', 0);
 	
-	PAGETABLE(VAddr >> 12) = PAddr | 3;
+	if( *ent & 1 )	LEAVE_RET('i', 0);
 	
+	*ent = PAddr | 3;
+
+	if( VAddr < 0x800000000000 )
+		*ent |= PF_USER;
+
+	INVLPG( VAddr );
+
+	LEAVE('i', 1);	
 	return 1;
 }
 
+/**
+ * \brief Map a physical page to a virtual one
+ * \param VAddr	Target virtual address
+ * \param PAddr	Physical address of page
+ */
+int MM_Map(tVAddr VAddr, tPAddr PAddr)
+{
+	return MM_MapEx(VAddr, PAddr, 0, 0);
+}
+
+/**
+ * \brief Removed a mapped page
+ */
 void MM_Unmap(tVAddr VAddr)
 {
 	// Check PML4
@@ -84,8 +456,9 @@ void MM_Unmap(tVAddr VAddr)
 	if( !(PAGEDIRPTR(VAddr >> 30) & 1) )	return ;
 	// Check Page Dir
 	if( !(PAGEDIR(VAddr >> 21) & 1) )	return ;
-	
-	PAGETABLE(VAddr >> 12) = 0;
+
+	PAGETABLE(VAddr >> PTAB_SHIFT) = 0;
+	INVLPG( VAddr );
 }
 
 /**
@@ -95,18 +468,51 @@ tPAddr MM_Allocate(tVAddr VAddr)
 {
 	tPAddr	ret;
 	
+	ENTER("xVAddr", VAddr);
+	
+	// Ensure the tables are allocated before the page (keeps things neat)
+	MM_GetPageEntryPtr(VAddr, 0, 1, 0, NULL);
+	
+	// Allocate the page
 	ret = MM_AllocPhys();
-	if(!ret)	return 0;
+	LOG("ret = %x", ret);
+	if(!ret)	LEAVE_RET('i', 0);
 	
 	if( !MM_Map(VAddr, ret) )
 	{
+		Warning("MM_Allocate: Unable to map. Strange, we should have errored earlier");
 		MM_DerefPhys(ret);
+		LEAVE('i');
 		return 0;
 	}
 	
+	LEAVE('X', ret);
+	return ret;
+}
+
+tPAddr MM_AllocateZero(tVAddr VAddr)
+{
+	tPAddr	ret = gMM_ZeroPage;
+	
+	MM_GetPageEntryPtr(VAddr, 0, 1, 0, NULL);
+
+	if(!gMM_ZeroPage) {
+		ret = gMM_ZeroPage = MM_AllocPhys();
+		MM_RefPhys(ret);	// Don't free this please
+		MM_Map(VAddr, ret);
+		memset((void*)VAddr, 0, 0x1000);
+	}
+	else {
+		MM_Map(VAddr, ret);
+	}
+	MM_RefPhys(ret);	// Refernce for this map
+	MM_SetFlags(VAddr, MM_PFLAG_COW, MM_PFLAG_COW);
 	return ret;
 }
 
+/**
+ * \brief Deallocate a page at a virtual address
+ */
 void MM_Deallocate(tVAddr VAddr)
 {
 	tPAddr	phys;
@@ -119,21 +525,42 @@ void MM_Deallocate(tVAddr VAddr)
 	MM_DerefPhys(phys);
 }
 
+/**
+ * \brief Get the page table entry of a virtual address
+ * \param Addr	Virtual Address
+ * \param Phys	Location to put the physical address
+ * \param Flags	Flags on the entry (set to zero if unmapped)
+ * \return Size of the entry (in address bits) - 12 = 4KiB page
+ */
+int MM_GetPageEntry(tVAddr Addr, tPAddr *Phys, Uint *Flags)
+{
+	tPAddr	*ptr;
+	 int	ret;
+	
+	if(!Phys || !Flags)	return 0;
+	
+	ret = MM_GetPageEntryPtr(Addr, 0, 0, 0, &ptr);
+	if( ret < 0 )	return 0;
+	
+	*Phys = *ptr & PADDR_MASK;
+	*Flags = *ptr & 0xFFF;
+	return ret;
+}
+
 /**
  * \brief Get the physical address of a virtual location
  */
 tPAddr MM_GetPhysAddr(tVAddr Addr)
 {
-	if( !(PAGEMAPLVL4(Addr >> 39) & 1) )
-		return 0;
-	if( !(PAGEDIRPTR(Addr >> 30) & 1) )
-		return 0;
-	if( !(PAGEDIR(Addr >> 21) & 1) )
-		return 0;
-	if( !(PAGETABLE(Addr >> 12) & 1) )
-		return 0;
+	tPAddr	*ptr;
+	 int	ret;
 	
-	return (PAGETABLE(Addr >> 12) & ~0xFFF) | (Addr & 0xFFF);
+	ret = MM_GetPageEntryPtr(Addr, 0, 0, 0, &ptr);
+	if( ret < 0 )	return 0;
+	
+	if( !(*ptr & 1) )	return 0;
+	
+	return (*ptr & PADDR_MASK) | (Addr & 0xFFF);
 }
 
 /**
@@ -142,19 +569,14 @@ tPAddr MM_GetPhysAddr(tVAddr Addr)
 void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 {
 	tPAddr	*ent;
+	 int	rv;
 	
-	// Validity Check
-	if( !(PAGEMAPLVL4(VAddr >> 39) & 1) )
-		return ;
-	if( !(PAGEDIRPTR(VAddr >> 30) & 1) )
-		return ;
-	if( !(PAGEDIR(VAddr >> 21) & 1) )
-		return ;
-	if( !(PAGETABLE(VAddr >> 12) & 1) )
-		return ;
+	// Get pointer
+	rv = MM_GetPageEntryPtr(VAddr, 0, 0, 0, &ent);
+	if(rv < 0)	return ;
 	
-	// Set Flags
-	ent = &PAGETABLE(VAddr >> 12);
+	// Ensure the entry is valid
+	if( !(*ent & 1) )	return ;
 	
 	// Read-Only
 	if( Mask & MM_PFLAG_RO )
@@ -209,20 +631,12 @@ void MM_SetFlags(tVAddr VAddr, Uint Flags, Uint Mask)
 Uint MM_GetFlags(tVAddr VAddr)
 {
 	tPAddr	*ent;
-	Uint	ret = 0;
+	 int	rv, ret = 0;
 	
-	// Validity Check
-	if( !(PAGEMAPLVL4(VAddr >> 39) & 1) )
-		return 0;
-	if( !(PAGEDIRPTR(VAddr >> 30) & 1) )
-		return 0;
-	if( !(PAGEDIR(VAddr >> 21) & 1) )
-		return 0;
-	if( !(PAGETABLE(VAddr >> 12) & 1) )
-		return 0;
+	rv = MM_GetPageEntryPtr(VAddr, 0, 0, 0, &ent);
+	if(rv < 0)	return 0;
 	
-	// Set Flags
-	ent = &PAGETABLE(VAddr >> 12);
+	if( !(*ent & 1) )	return 0;
 	
 	// Read-Only
 	if( !(*ent & PF_WRITE) )	ret |= MM_PFLAG_RO;
@@ -242,7 +656,34 @@ Uint MM_GetFlags(tVAddr VAddr)
  */
 tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
 {
-	Log_KernelPanic("MM", "TODO: Implement MM_MapHWPages");
+	tVAddr	ret;
+	 int	num;
+	
+	//TODO: Add speedups (memory of first possible free)
+	for( ret = MM_HWMAP_BASE; ret < MM_HWMAP_TOP; ret += 0x1000 )
+	{
+		for( num = Number; num -- && ret < MM_HWMAP_TOP; ret += 0x1000 )
+		{
+			if( MM_GetPhysAddr(ret) != 0 )	break;
+		}
+		if( num >= 0 )	continue;
+		
+//		Log_Debug("MMVirt", "Mapping %i pages to %p (base %P)", Number, ret-Number*0x1000, PAddr);
+
+		PAddr += 0x1000 * Number;
+		
+		while( Number -- )
+		{
+			ret -= 0x1000;
+			PAddr -= 0x1000;
+			MM_Map(ret, PAddr);
+			MM_RefPhys(PAddr);
+		}
+		
+		return ret;
+	}
+	
+	Log_Error("MM", "MM_MapHWPages - No space for %i pages", Number);
 	return 0;
 }
 
@@ -251,18 +692,291 @@ tVAddr MM_MapHWPages(tPAddr PAddr, Uint Number)
  */
 void MM_UnmapHWPages(tVAddr VAddr, Uint Number)
 {
-	Log_KernelPanic("MM", "TODO: Implement MM_UnmapHWPages");
+//	Log_KernelPanic("MM", "TODO: Implement MM_UnmapHWPages");
+	while( Number -- )
+	{
+		MM_DerefPhys( MM_GetPhysAddr(VAddr) );
+		MM_Unmap(VAddr);
+		VAddr += 0x1000;
+	}
+}
+
+
+/**
+ * \fn tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
+ * \brief Allocates DMA physical memory
+ * \param Pages	Number of pages required
+ * \param MaxBits	Maximum number of bits the physical address can have
+ * \param PhysAddr	Pointer to the location to place the physical address allocated
+ * \return Virtual address allocate
+ */
+tVAddr MM_AllocDMA(int Pages, int MaxBits, tPAddr *PhysAddr)
+{
+	tPAddr	phys;
+	tVAddr	ret;
+	
+	// Sanity Check
+	if(MaxBits < 12 || !PhysAddr)	return 0;
+	
+	// Fast Allocate
+	if(Pages == 1 && MaxBits >= PHYS_BITS)
+	{
+		phys = MM_AllocPhys();
+		*PhysAddr = phys;
+		ret = MM_MapHWPages(phys, 1);
+		MM_DerefPhys(phys);
+		return ret;
+	}
+	
+	// Slow Allocate
+	phys = MM_AllocPhysRange(Pages, MaxBits);
+	// - Was it allocated?
+	if(phys == 0)	return 0;
+	
+	// Allocated successfully, now map
+	ret = MM_MapHWPages(phys, Pages);
+	// MapHWPages references the pages, so deref them back down to 1
+	for(;Pages--;phys+=0x1000)
+		MM_DerefPhys(phys);
+	if( ret == 0 ) {
+		// If it didn't map, free then return 0
+		return 0;
+	}
+	
+	*PhysAddr = phys;
+	return ret;
 }
 
 // --- Tempory Mappings ---
 tVAddr MM_MapTemp(tPAddr PAddr)
 {
-	Log_KernelPanic("MM", "TODO: Implement MM_MapTemp");
+	const int max_slots = (MM_TMPMAP_END - MM_TMPMAP_BASE) / PAGE_SIZE;
+	tVAddr	ret = MM_TMPMAP_BASE;
+	 int	i;
+	
+	for( i = 0; i < max_slots; i ++, ret += PAGE_SIZE )
+	{
+		tPAddr	*ent;
+		if( MM_GetPageEntryPtr( ret, 0, 1, 0, &ent) < 0 ) {
+			continue ;
+		}
+
+		if( *ent & 1 )
+			continue ;
+
+		*ent = PAddr | 3;
+		MM_RefPhys(PAddr);
+		INVLPG(ret);
+		return ret;
+	}
 	return 0;
 }
 
 void MM_FreeTemp(tVAddr VAddr)
 {
-	Log_KernelPanic("MM", "TODO: Implement MM_FreeTemp");
+	MM_Deallocate(VAddr);
 	return ;
 }
+
+
+// --- Address Space Clone --
+tPAddr MM_Clone(void)
+{
+	tPAddr	ret;
+	 int	i;
+	tVAddr	kstackbase;
+
+	// #1 Create a copy of the PML4
+	ret = MM_AllocPhys();
+	if(!ret)	return 0;
+	
+	// #2 Alter the fractal pointer
+	Mutex_Acquire(&glMM_TempFractalLock);
+	TMPCR3() = ret | 3;
+	INVLPG_ALL();
+	
+	// #3 Set Copy-On-Write to all user pages
+	for( i = 0; i < 256; i ++)
+	{
+		if( PAGEMAPLVL4(i) & PF_WRITE ) {
+			PAGEMAPLVL4(i) |= PF_COW;
+			PAGEMAPLVL4(i) &= ~PF_WRITE;
+		}
+
+		TMPMAPLVL4(i) = PAGEMAPLVL4(i);
+//		Log_Debug("MM", "TMPMAPLVL4(%i) = 0x%016llx", i, TMPMAPLVL4(i));
+		if( !(TMPMAPLVL4(i) & PF_PRESENT) )	continue ;
+		
+		MM_RefPhys( TMPMAPLVL4(i) & PADDR_MASK );
+	}
+	
+	// #4 Map in kernel pages
+	for( i = 256; i < 512; i ++ )
+	{
+		// Skip addresses:
+		// 320 0xFFFFA....	- Kernel Stacks
+		if( i == 320 )	continue;
+		// 509 0xFFFFFE0..	- Fractal mapping
+		if( i == 508 )	continue;
+		// 510 0xFFFFFE8..	- Temp fractal mapping
+		if( i == 509 )	continue;
+		
+		TMPMAPLVL4(i) = PAGEMAPLVL4(i);
+		if( TMPMAPLVL4(i) & 1 )
+			MM_RefPhys( TMPMAPLVL4(i) & PADDR_MASK );
+	}
+
+	// Mark Per-Process data as COW
+	TMPMAPLVL4(MM_PPD_BASE>>39) |= PF_COW;
+	TMPMAPLVL4(MM_PPD_BASE>>39) &= ~PF_WRITE;
+	
+	// #5 Set fractal mapping
+	TMPMAPLVL4(MM_FRACTAL_BASE>>39) = ret | 3;	// Main
+	TMPMAPLVL4(MM_TMPFRAC_BASE>>39) = 0;	// Temp
+	
+	// #6 Create kernel stack
+	//  tThread->KernelStack is the top
+	//  There is 1 guard page below the stack
+	kstackbase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
+
+	// Clone stack
+	TMPMAPLVL4(MM_KSTACK_BASE >> PML4_SHIFT) = 0;
+	for( i = 1; i < KERNEL_STACK_SIZE/0x1000; i ++ )
+	{
+		tPAddr	phys = MM_AllocPhys();
+		tVAddr	tmpmapping;
+		MM_MapEx(kstackbase+i*0x1000, phys, 1, 0);
+		
+		tmpmapping = MM_MapTemp(phys);
+		if( MM_GetPhysAddr( kstackbase+i*0x1000 ) )
+			memcpy((void*)tmpmapping, (void*)(kstackbase+i*0x1000), 0x1000);
+		else
+			memset((void*)tmpmapping, 0, 0x1000);
+//		if( i == 0xF )
+//			Debug_HexDump("MM_Clone: *tmpmapping = ", (void*)tmpmapping, 0x1000);
+		MM_FreeTemp(tmpmapping);
+	}
+	
+//	MAGIC_BREAK();
+
+	// #7 Return
+	TMPCR3() = 0;
+	INVLPG_ALL();
+	Mutex_Release(&glMM_TempFractalLock);
+//	Log("MM_Clone: RETURN %P", ret);
+	return ret;
+}
+
+void MM_int_ClearTableLevel(tVAddr VAddr, int LevelBits, int MaxEnts)
+{
+	Uint64	* const table_bases[] = {&PAGETABLE(0), &PAGEDIR(0), &PAGEDIRPTR(0), &PAGEMAPLVL4(0)};
+	Uint64	*table = table_bases[(LevelBits-12)/9] + (VAddr >> LevelBits);
+	 int	i;
+//	Log("MM_int_ClearTableLevel: (VAddr=%p, LevelBits=%i, MaxEnts=%i)", VAddr, LevelBits, MaxEnts);
+	for( i = 0; i < MaxEnts; i ++ )
+	{
+		// Skip non-present tables
+		if( !(table[i] & PF_PRESENT) ) {
+			table[i] = 0;
+			continue ;
+		}
+	
+		if( (table[i] & PF_COW) && MM_GetRefCount(table[i] & PADDR_MASK) > 1 ) {
+			MM_DerefPhys(table[i] & PADDR_MASK);
+			table[i] = 0;
+			continue ;
+		}
+		// Clear table contents (if it is a table)
+		if( LevelBits > 12 )
+			MM_int_ClearTableLevel(VAddr + ((tVAddr)i << LevelBits), LevelBits-9, 512);
+		MM_DerefPhys(table[i] & PADDR_MASK);
+		table[i] = 0;
+	}
+}
+
+void MM_ClearUser(void)
+{
+	MM_int_ClearTableLevel(0, 39, 256);	
+}
+
+tVAddr MM_NewWorkerStack(void *StackData, size_t StackSize)
+{
+	tVAddr	ret;
+	 int	i;
+	
+	// #1 Set temp fractal to PID0
+	Mutex_Acquire(&glMM_TempFractalLock);
+	TMPCR3() = ((tPAddr)gInitialPML4 - KERNEL_BASE) | 3;
+	
+	// #2 Scan for a free stack addresss < 2^47
+	for(ret = 0x100000; ret < (1ULL << 47); ret += KERNEL_STACK_SIZE)
+	{
+		tPAddr	*ptr;
+		if( MM_GetPageEntryPtr(ret, 1, 0, 0, &ptr) <= 0 )	break;
+		if( !(*ptr & 1) )	break;
+	}
+	if( ret >= (1ULL << 47) ) {
+		Mutex_Release(&glMM_TempFractalLock);
+		return 0;
+	}
+	
+	// #3 Map all save the last page in the range
+	//    - This acts as as guard page, and doesn't cost us anything.
+	for( i = 0; i < KERNEL_STACK_SIZE/0x1000 - 1; i ++ )
+	{
+		tPAddr	phys = MM_AllocPhys();
+		if(!phys) {
+			// TODO: Clean up
+			Log_Error("MM", "MM_NewWorkerStack - Unable to allocate page");
+			return 0;
+		}
+		MM_MapEx(ret + i*0x1000, phys, 1, 0);
+	}
+
+	if( StackSize > 0x1000 ) {
+		Log_Error("MM", "MM_NewWorkerStack: StackSize(0x%x) > 0x1000, cbf handling", StackSize);
+	}
+	else {
+		tPAddr	*ptr, paddr;
+		tVAddr	tmp_addr;
+		MM_GetPageEntryPtr(ret + i*0x1000, 1, 0, 0, &ptr);
+		paddr = *ptr & ~0xFFF;
+		tmp_addr = MM_MapTemp(paddr);
+		memcpy( (void*)(tmp_addr + (0x1000 - StackSize)), StackData, StackSize );
+		MM_FreeTemp(tmp_addr);
+	}
+	
+	Mutex_Release(&glMM_TempFractalLock);
+	
+	return ret + i*0x1000;
+}
+
+/**
+ * \brief Allocate a new kernel stack
+ */
+tVAddr MM_NewKStack(void)
+{
+	tVAddr	base = MM_KSTACK_BASE;
+	Uint	i;
+	for( ; base < MM_KSTACK_TOP; base += KERNEL_STACK_SIZE )
+	{
+		if(MM_GetPhysAddr(base+KERNEL_STACK_SIZE-0x1000) != 0)
+			continue;
+		
+		//Log("MM_NewKStack: Found one at %p", base + KERNEL_STACK_SIZE);
+		for( i = 0x1000; i < KERNEL_STACK_SIZE; i += 0x1000)
+		{
+			if( !MM_Allocate(base+i) )
+			{
+				Log_Warning("MM", "MM_NewKStack - Allocation failed");
+				for( i -= 0x1000; i; i -= 0x1000)
+					MM_Deallocate(base+i);
+				return 0;
+			}
+		}
+		
+		return base + KERNEL_STACK_SIZE;
+	}
+	Log_Warning("MM", "MM_NewKStack - No address space left\n");
+	return 0;
+}