+// 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)
+{
+// Log_Debug("MMVirt", "Addr = %p, ErrorCode = %x", Addr, ErrorCode);
+
+ // Catch reserved bits first
+ if( ErrorCode & 0x8 )
+ {
+ Log_Warning("MMVirt", "Reserved bits trashed!");
+ Log_Warning("MMVirt", "PML4 Ent = %P", PAGEMAPLVL4(Addr>>39));
+ if( !(PAGEMAPLVL4(Addr>>39) & PF_PRESENT) ) goto print_done;
+ Log_Warning("MMVirt", "PDP Ent = %P", PAGEDIRPTR(Addr>>30));
+ if( !(PAGEDIRPTR(Addr>>30) & PF_PRESENT) ) goto print_done;
+ Log_Warning("MMVirt", "PDir Ent = %P", PAGEDIR(Addr>>21));
+ if( !(PAGEDIR(Addr>>21) & PF_PRESENT) ) goto print_done;
+ Log_Warning("MMVirt", "PTable Ent = %P", PAGETABLE(Addr>>12));
+ if( !(PAGETABLE(Addr>>12) & PF_PRESENT) ) goto print_done;
+ print_done:
+
+ for(;;);
+ }
+
+ // 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;
+ }