From e41b764ac64130800a1a670000346998b446b6d0 Mon Sep 17 00:00:00 2001
From: vanten-s <vanten-s@vanten-s.com>
Date: Thu, 13 Nov 2025 21:57:20 +0100
Subject: [PATCH] Quick fixes, just changing order and makes a reference to the
 newly mapped higher-half page-directory

---
 src/arch/i686/initialize_pages.c |  8 ++---
 src/arch/i686/paging.cpp         | 50 ++++++++++++++++++--------------
 2 files changed, 30 insertions(+), 28 deletions(-)

diff --git a/src/arch/i686/initialize_pages.c b/src/arch/i686/initialize_pages.c
index 850c5f8..e898a62 100644
--- a/src/arch/i686/initialize_pages.c
+++ b/src/arch/i686/initialize_pages.c
@@ -34,12 +34,9 @@ extern const size_t _kernel_end;
 
 struct PageDirectoryEntry _page_directory[1024] __attribute__((aligned(4096))); // Create a page directory with 1024 entries and make sure it's 4 KiB aligned
 
-// Identity page table for lowest 4 MiB, including this
+// Identity page table for lowest 4 MiB, including this. This will be the table where the (current) kernel will be stored
 struct PageTableEntry _identity_page_table[1024] __attribute__((aligned(4096)));
 
-// Assumes kernel is smaller than 4 MiB, should change later
-struct PageTableEntry _kernel_page_table[1024] __attribute__((aligned(4096)));
-
 void initialize_pages() {
     struct PageDirectoryEntry identity_pd_entry = {
         .page_table_address = (size_t)(_identity_page_table) >> 12,
@@ -50,6 +47,7 @@ void initialize_pages() {
     };
 
     _page_directory[0] = identity_pd_entry;
+    _page_directory[768] = identity_pd_entry;
 
     // Identity page lowest 4 MiB to not crash instantly
     for (size_t i = 0; i < mib(4) / kib(4); i++) {
@@ -62,8 +60,6 @@ void initialize_pages() {
         _identity_page_table[i] = table_entry;
     }
 
-    _page_directory[768] = identity_pd_entry;
-
     asm("mov %0, %%cr3" :: "r" (_page_directory));
     uint32_t control_register_0;
     asm("mov %%cr0, %0" : "=r" (control_register_0));
diff --git a/src/arch/i686/paging.cpp b/src/arch/i686/paging.cpp
index 9fa3ac5..95c8141 100644
--- a/src/arch/i686/paging.cpp
+++ b/src/arch/i686/paging.cpp
@@ -27,32 +27,38 @@
 Page pages[NUM_PAGES];
 
 struct PageDirectoryEntry {
-    uint32_t page_table_address : 20;
-    uint32_t available_1 : 4;
-    bool size : 1;
-    bool available_2 : 1;
-    bool accessed : 1;
-    bool cache_disabled : 1;
-    bool write_through : 1;
-    bool user : 1;
-    bool write : 1;
     bool present : 1;
+    bool write : 1;
+    bool user : 1;
+    bool write_through : 1;
+    bool cache_disabled : 1;
+    bool accessed : 1;
+    bool available_2 : 1;
+    bool size : 1;
+    size_t available_1 : 4;
+    size_t page_table_address : 20;
 } __attribute__((packed)); // Force the compiler to keep our structure intact.
 
 struct PageTableEntry {
-    uint32_t physical_address : 20;
-    uint32_t available : 3;
-    bool global : 1;
-    bool pat : 1;
-    bool dirty : 1;
-    bool accessed : 1;
-    bool cache_disabled : 1;
-    bool write_through : 1;
-    bool user : 1;
-    bool write : 1;
     bool present : 1;
+    bool write : 1;
+    bool user : 1;
+    bool write_through : 1;
+    bool cache_disabled : 1;
+    bool accessed : 1;
+    bool dirty : 1;
+    bool pat : 1;
+    bool global : 1;
+    size_t available : 3;
+    size_t physical_address : 20;
 } __attribute__((packed));
 
+extern "C" PageDirectoryEntry _page_directory[1024];
+extern "C" PageTableEntry _identity_page_table[1024];
+
+PageDirectoryEntry* page_directory;
+PageTableEntry* identity_page_table;
+PageTableEntry* kernel_page_table;
 PageDirectoryEntry dynamic_page_table[1024] __attribute__((aligned(4096))); // Create a page directory with 1024 entries and make sure it's 4 KiB aligned
 
 Page::Page() { }
@@ -112,9 +118,9 @@ size_t Page::pt_entry() {
 
 void Page::initialize() {
     // Allocate the lowest 1 MiB of both virtual and physical memory to BIOS
-    for (size_t i = 0; i < mib(1); i += kib(4)) {
-        Page::alloc_fixed((void*)i, (void*)i);
-    }
+
+    page_directory = (struct PageDirectoryEntry*)((size_t)(_page_directory) + 0xC0000000);
+    identity_page_table = (struct PageTableEntry*)((size_t)(_identity_page_table) + 0xC0000000);
 
     /* for (size_t index = _kernel_start; index + kib(4) < _kernel_end; index += kib(4)) {
         Page::alloc_fixed(void *physical_address, void *virtual_addr)