From 7b6e284d394a2ba9f3e315abe116315aea9fa44e Mon Sep 17 00:00:00 2001
From: Aiken Harris <harraiken91@gmail.com>
Date: Tue, 3 Feb 2026 22:28:17 +0100
Subject: [PATCH] Refactor PFN database initialization loop on i686

---
 xtoskrnl/mm/i686/pfn.cc | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/xtoskrnl/mm/i686/pfn.cc b/xtoskrnl/mm/i686/pfn.cc
index a939809..e34db8a 100644
--- a/xtoskrnl/mm/i686/pfn.cc
+++ b/xtoskrnl/mm/i686/pfn.cc
@@ -69,27 +69,36 @@ MM::Pfn::InitializePfnDatabase(VOID)
             continue;
         }
 
-        /* Split PFN DB allocation out of free descriptor */
+        /* Check if this is the modified free descriptor */
         if(Descriptor == FreeDescriptor)
         {
-            /* Initialize PFNs for the remaining free memory after the PFN database */
-            ProcessMemoryDescriptor(OriginalFreeDescriptor.BasePage + MemoryLayout->PfnDatabaseSize,
-                                    OriginalFreeDescriptor.PageCount - MemoryLayout->PfnDatabaseSize,
-                                    LoaderFree);
+            /* Switch to the original descriptor */
+            Descriptor = &OriginalFreeDescriptor;
+        }
 
-            /* Initialize PFNs for the physical pages backing the PFN database itself */
-            ProcessMemoryDescriptor(OriginalFreeDescriptor.BasePage, MemoryLayout->PfnDatabaseSize, LoaderMemoryData);
-        }
-        else
+        /* Check if the free memory block that was split is being processed */
+        if(Descriptor == &OriginalFreeDescriptor)
         {
-            /* Initialize PFNs for the physical pages described by this descriptor */
-            ProcessMemoryDescriptor(Descriptor->BasePage, Descriptor->PageCount, Descriptor->MemoryType);
+            /* Skip loop processing, free memory is initialized separately */
+            ListEntry = ListEntry->Flink;
+            continue;
         }
 
+        /* Initialize PFNs for this memory range */
+        ProcessMemoryDescriptor(Descriptor->BasePage, Descriptor->PageCount, Descriptor->MemoryType);
+
         /* Move to the next descriptor */
         ListEntry = ListEntry->Flink;
     }
 
+    /* Initialize PFNs for the free memory */
+    ProcessMemoryDescriptor(FreeDescriptor->BasePage, FreeDescriptor->PageCount, LoaderFree);
+
+    /* Initialize PFNs for the physical pages backing the PFN database */
+    ProcessMemoryDescriptor(OriginalFreeDescriptor.BasePage,
+                            FreeDescriptor->BasePage - OriginalFreeDescriptor.BasePage,
+                            LoaderMemoryData);
+
     /* Restore original free descriptor */
     *FreeDescriptor = OriginalFreeDescriptor;