Refactor PFN linking logic

2026-02-25 19:27:53 +01:00
parent 44fa2ca13a
commit bfdb7bc476
3 changed files with 109 additions and 51 deletions
--- a/xtoskrnl/includes/mm/pfn.hh
+++ b/xtoskrnl/includes/mm/pfn.hh
@@ -49,9 +49,12 @@ namespace MM
            STATIC XTAPI ULONGLONG GetNumberOfPhysicalPages(VOID);
            STATIC XTAPI PMMPFN GetPfnEntry(IN PFN_NUMBER Pfn);
            STATIC XTAPI VOID InitializePfnDatabase(VOID);
-            STATIC VOID XTAPI LinkPfnToPte(IN PFN_NUMBER PageFrameIndex,
+            STATIC XTAPI VOID LinkPfn(IN PFN_NUMBER PageFrameIndex,
                                      IN PMMPTE PointerPte,
                                      IN BOOLEAN Modified);
+            STATIC XTAPI VOID LinkPfnWithParent(IN PFN_NUMBER PageFrameIndex,
+                                                IN PMMPTE PointerPte,
+                                                IN PFN_NUMBER ParentFrame);
            STATIC XTAPI VOID ScanMemoryDescriptors(VOID);

        private:
--- a/xtoskrnl/mm/kpool.cc
+++ b/xtoskrnl/mm/kpool.cc
@@ -76,7 +76,7 @@ MM::KernelPool::AllocateKernelStack(OUT PVOID *Stack,
        *PointerPte = InvalidPte;

        /* Associate the physical page with its corresponding PTE in the PFN database */
-        MM::Pfn::LinkPfnToPte(PageFrameIndex, PointerPte, 1);
+        MM::Pfn::LinkPfn(PageFrameIndex, PointerPte, TRUE);

        /* Make the PTE valid, mapping the virtual address to the physical page */
        MM::Paging::SetPte(&TempPte, PageFrameIndex, 0);
--- a/xtoskrnl/mm/pfn.cc
+++ b/xtoskrnl/mm/pfn.cc
@@ -730,55 +730,6 @@ MM::Pfn::LinkPage(IN PMMPFNLIST ListHead,
    }
 }

-/**
- * Initializes the PFN database entry for a physical page that is used as a page table.
- *
- * @param PageFrameIndex
- *        The page frame number of the physical page being used as a page table.
- *
- * @param PointerPte
- *        A pointer to the higher-level PTE that maps this page table page.
- *
- * @return This routine does not return any value.
- *
- * @since XT 1.0
- */
-XTAPI
-VOID
-MM::Pfn::LinkPfnForPageTable(IN PFN_NUMBER PageFrameIndex,
-                             IN PMMPTE PointerPte)
-{
-    PMMPFN Pfn;
-    PMMPDE PointerPde;
-    PVOID EndAddress;
-
-    /* Retrieve the PFN database entry for the physical page of the page table */
-    Pfn = GetPfnEntry(PageFrameIndex);
-
-    /* Calculate the end address of the PFN entry to ensure it's mapped */
-    EndAddress = (PUCHAR)(Pfn + 1) - 1;
-
-    /* Validate that the PFN entry corresponds to a valid, active physical page */
-    if((PageFrameIndex <= HighestPhysicalPage) && (MM::Pte::AddressValid(Pfn)) &&
-       (MM::Pte::AddressValid(EndAddress)) && (Pfn->u3.e1.PageLocation == ActiveAndValid))
-    {
-        /* Initialize the PFN entry for this page table page */
-        Pfn->OriginalPte = *PointerPte;
-        Pfn->PteAddress = PointerPte;
-        Pfn->u1.WsIndex = 0;
-        Pfn->u2.ShareCount++;
-        Pfn->u3.e1.CacheAttribute = PfnNonCached;
-        Pfn->u3.e1.PageLocation = ActiveAndValid;
-        Pfn->u3.e2.ReferenceCount = 1;
-        Pfn->u4.PteFrame = MM::Paging::GetPageFrameNumber(MM::Paging::GetPteAddress(PointerPte));
-    }
-
-    /* Increment the share count of the parent page table that contains the mapping */
-    PointerPde = MM::Paging::GetPdeAddress(MM::Paging::GetPteVirtualAddress(PointerPte));
-    Pfn = GetPfnEntry(MM::Paging::GetPageFrameNumber(PointerPde));
-    Pfn->u2.ShareCount++;
-}
-
 /**
 * Links a PFN entry to its corresponding PTE and ensures the page table that contains the PTE is resident in memory.
 *
@@ -797,7 +748,7 @@ MM::Pfn::LinkPfnForPageTable(IN PFN_NUMBER PageFrameIndex,
 */
 XTAPI
 VOID
-MM::Pfn::LinkPfnToPte(IN PFN_NUMBER PageFrameIndex,
+MM::Pfn::LinkPfn(IN PFN_NUMBER PageFrameIndex,
                 IN PMMPTE PointerPte,
                 IN BOOLEAN Modified)
 {
@@ -857,6 +808,110 @@ MM::Pfn::LinkPfnToPte(IN PFN_NUMBER PageFrameIndex,
    Pfn->u2.ShareCount++;
 }

+/**
+ * Initializes the PFN database entry for a physical page that is used as a page table.
+ *
+ * @param PageFrameIndex
+ *        The page frame number of the physical page being used as a page table.
+ *
+ * @param PointerPte
+ *        A pointer to the higher-level PTE that maps this page table page.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+MM::Pfn::LinkPfnForPageTable(IN PFN_NUMBER PageFrameIndex,
+                             IN PMMPTE PointerPte)
+{
+    PMMPFN Pfn;
+    PMMPDE PointerPde;
+    PVOID EndAddress;
+
+    /* Retrieve the PFN database entry for the physical page of the page table */
+    Pfn = GetPfnEntry(PageFrameIndex);
+
+    /* Calculate the end address of the PFN entry to ensure it's mapped */
+    EndAddress = (PUCHAR)(Pfn + 1) - 1;
+
+    /* Validate that the PFN entry corresponds to a valid, active physical page */
+    if((PageFrameIndex <= HighestPhysicalPage) && (MM::Pte::AddressValid(Pfn)) &&
+       (MM::Pte::AddressValid(EndAddress)) && (Pfn->u3.e1.PageLocation == ActiveAndValid))
+    {
+        /* Initialize the PFN entry for this page table page */
+        Pfn->OriginalPte = *PointerPte;
+        Pfn->PteAddress = PointerPte;
+        Pfn->u1.WsIndex = 0;
+        Pfn->u2.ShareCount++;
+        Pfn->u3.e1.CacheAttribute = PfnNonCached;
+        Pfn->u3.e1.PageLocation = ActiveAndValid;
+        Pfn->u3.e2.ReferenceCount = 1;
+        Pfn->u4.PteFrame = MM::Paging::GetPageFrameNumber(MM::Paging::GetPteAddress(PointerPte));
+    }
+
+    /* Increment the share count of the parent page table that contains the mapping */
+    PointerPde = MM::Paging::GetPdeAddress(MM::Paging::GetPteVirtualAddress(PointerPte));
+    Pfn = GetPfnEntry(MM::Paging::GetPageFrameNumber(PointerPde));
+    Pfn->u2.ShareCount++;
+}
+
+/**
+ * Links a PFN entry to its corresponding PTE and ensures the page table that contains the PTE is resident in memory.
+ *
+ * @param PageFrameIndex
+ *        Supplies the index into the PFN database for the page being initialized.
+ *
+ * @param PointerPte
+ *        Supplies the pointer to the PTE which maps the physical page.
+ *
+ * @param ParentFrame
+ *        Supplies the page frame number of the page table that contains the PTE.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+MM::Pfn::LinkPfnWithParent(IN PFN_NUMBER PageFrameIndex,
+                           IN PMMPTE PointerPte,
+                           IN PFN_NUMBER ParentFrame)
+{
+    PMMMEMORY_LAYOUT MemoryLayout;
+    PMMPFN Pfn;
+
+    /* Get the memory layout */
+    MemoryLayout = MM::Manager::GetMemoryLayout();
+
+    /* Point the PFN to its PTE */
+    Pfn = &((PMMPFN)MemoryLayout->PfnDatabase)[PageFrameIndex];
+    Pfn->PteAddress = PointerPte;
+
+    /* Initialize the PTE */
+    MM::Paging::SetPte(&Pfn->OriginalPte, 0, MM_PTE_GUARDED);
+
+    /* Initialize the PFN entry */
+    Pfn->u2.ShareCount++;
+    Pfn->u3.e1.CacheAttribute = PfnCached;
+    Pfn->u3.e1.Modified = TRUE;
+    Pfn->u3.e1.PageLocation = ActiveAndValid;
+    Pfn->u3.e2.ReferenceCount++;
+    Pfn->u4.InPageError = FALSE;
+
+    /* Check if parent PTE frame exists */
+    if(ParentFrame)
+    {
+        /* Link the page table to its parent */
+        Pfn->u4.PteFrame = ParentFrame;
+
+        /* Get the PFN entry for parent PTE and increment share count */
+        Pfn = &((PMMPFN)MemoryLayout->PfnDatabase)[ParentFrame];
+        Pfn->u2.ShareCount++;
+    }
+}
+
 /**
 * Links a page to the beginning of the appropriate standby or ROM list.
 *