Implement TLB flushing for cache attribute changes during page removal

xtoskrnl/includes/mm/amd64/paging.hh

@@ -25,6 +25,7 @@ namespace MM
                                            IN LONG Count);
             STATIC XTAPI BOOLEAN CanonicalAddress(IN PVOID VirtualAddress);
             STATIC XTAPI VOID ClearPte(IN PMMPTE PtePointer);
+            STATIC XTAPI VOID FlushEntireTlb(VOID);
             STATIC XTAPI VOID FlushTlb(VOID);
             STATIC XTAPI ULONG_PTR GetNextEntry(IN PMMPTE Pte);
             STATIC XTAPI PMMPTE GetNextPte(IN PMMPTE Pte);

xtoskrnl/includes/mm/i686/paging.hh

@@ -25,6 +25,7 @@ namespace MM
                                            IN LONG Count);
             STATIC XTAPI BOOLEAN CanonicalAddress(IN PVOID VirtualAddress);
             STATIC XTAPI VOID ClearPte(IN PMMPTE PtePointer);
+            STATIC XTAPI VOID FlushEntireTlb(VOID);
             STATIC XTAPI VOID FlushTlb(VOID);
             STATIC XTAPI ULONG_PTR GetNextEntry(IN PMMPTE Pte);
             STATIC XTAPI PMMPTE GetNextPte(IN PMMPTE Pte);

xtoskrnl/mm/paging.cc

@@ -68,7 +68,22 @@ MM::Paging::ClearPte(IN PMMPTE PtePointer)
 }
 
 /**
- * Flushes current Translation Lookaside Buffer (TLB)
+ * Flushes the entire Translation Lookaside Buffer (TLB) on all processors.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+MM::Paging::FlushEntireTlb(VOID)
+{
+    /* Temporarily fallback to FlushTlb() as SMP is not supported yet */
+    FlushTlb();
+}
+
+/**
+ * Flushes current Translation Lookaside Buffer (TLB).
  *
  * @return This routine does not return any value.
  *

xtoskrnl/mm/pfn.cc

@@ -191,7 +191,8 @@ MM::Pfn::DecrementReferenceCount(IN PMMPFN PageFrameNumber,
         if((PageFrameNumber->u3.e1.CacheAttribute != PfnCached) &&
            (PageFrameNumber->u3.e1.CacheAttribute != PfnNotMapped))
         {
-            UNIMPLEMENTED;
+            /* Flush the TLB to prevent cache attribute conflicts from stale non-cached mappings */
+            MM::Paging::FlushEntireTlb();
         }
 
         /* The page is no longer needed, free it by linking it to the free list */
@@ -288,7 +289,7 @@ MM::Pfn::DecrementShareCount(IN PMMPFN PageFrameNumber,
         if(PageFrameNumber->u3.e2.ReferenceCount == 1)
         {
             /* Check if the PTE is marked as being ready for removal */
-            if(MM::Paging::GetPte(PageFrameNumber->PteAddress) & 0x1)
+            if((ULONG_PTR)PageFrameNumber->PteAddress & 0x1)
             {
                 /* Reset the reference count */
                 PageFrameNumber->u3.e2.ReferenceCount = 0;
@@ -297,7 +298,8 @@ MM::Pfn::DecrementShareCount(IN PMMPFN PageFrameNumber,
                 if((PageFrameNumber->u3.e1.CacheAttribute != PfnCached) &&
                    (PageFrameNumber->u3.e1.CacheAttribute != PfnNotMapped))
                 {
-                    UNIMPLEMENTED;
+                    /* Flush the TLB to prevent cache attribute conflicts from stale non-cached mappings */
+                    MM::Paging::FlushEntireTlb();
                 }
 
                 /* Mark the page as active and valid again */