From 0116fd3b382dd2e0b3d2cda33a8d27914f4f81f5 Mon Sep 17 00:00:00 2001
From: Alex <enderice2@users.noreply.github.com>
Date: Mon, 5 Dec 2022 06:02:25 +0200
Subject: [PATCH] Oops, SetFlag() should not clear the entire data

---
 Core/Memory/PageDirectoryEntry.cpp   | 2 +-
 Core/Memory/VirtualMemoryManager.cpp | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/Core/Memory/PageDirectoryEntry.cpp b/Core/Memory/PageDirectoryEntry.cpp
index 8c95881..1fdbddf 100644
--- a/Core/Memory/PageDirectoryEntry.cpp
+++ b/Core/Memory/PageDirectoryEntry.cpp
@@ -7,7 +7,7 @@ namespace Memory
     void PageDirectoryEntry::ClearFlags() { this->Value.raw = 0; }
     void PageDirectoryEntry::SetFlag(uint64_t Flag, bool Enabled)
     {
-        this->Value.raw = 0;
+        this->Value.raw &= ~Flag;
         if (Enabled)
             this->Value.raw |= Flag;
     }
diff --git a/Core/Memory/VirtualMemoryManager.cpp b/Core/Memory/VirtualMemoryManager.cpp
index 9db6078..4c62976 100644
--- a/Core/Memory/VirtualMemoryManager.cpp
+++ b/Core/Memory/VirtualMemoryManager.cpp
@@ -57,6 +57,7 @@ namespace Memory
         {
             PDP = (PageTable *)KernelAllocator.RequestPage();
             memset(PDP, 0, PAGE_SIZE);
+            PDE.ClearFlags();
             PDE.SetFlag(PTFlag::P, true);
             PDE.AddFlag(Flags);
             PDE.SetAddress((uint64_t)PDP >> 12);
@@ -71,6 +72,7 @@ namespace Memory
         {
             PD = (PageTable *)KernelAllocator.RequestPage();
             memset(PD, 0, PAGE_SIZE);
+            PDE.ClearFlags();
             PDE.SetFlag(PTFlag::P, true);
             PDE.AddFlag(Flags);
             PDE.SetAddress((uint64_t)PD >> 12);
@@ -85,6 +87,7 @@ namespace Memory
         {
             PT = (PageTable *)KernelAllocator.RequestPage();
             memset(PT, 0, PAGE_SIZE);
+            PDE.ClearFlags();
             PDE.SetFlag(PTFlag::P, true);
             PDE.AddFlag(Flags);
             PDE.SetAddress((uint64_t)PT >> 12);
@@ -94,6 +97,7 @@ namespace Memory
             PT = (PageTable *)((uint64_t)PDE.GetAddress() << 12);
 
         PDE = PT->Entries[Index.PIndex];
+        PDE.ClearFlags();
         PDE.SetFlag(PTFlag::P, true);
         PDE.AddFlag(Flags);
         PDE.SetAddress((uint64_t)PhysicalAddress >> 12);