Changes in kernel/genarch/src/mm/page_pt.c [17af882:346b12a2] in mainline

File:

• kernel/genarch/src/mm/page_pt.c (modified) (4 diffs)

kernel/genarch/src/mm/page_pt.c

@@ -53 +53 @@
 static void pt_mapping_insert(as_t *, uintptr_t, uintptr_t, unsigned int);
 static void pt_mapping_remove(as_t *, uintptr_t);
-static pte_t *pt_mapping_find(as_t *, uintptr_t, bool);
+static bool pt_mapping_find(as_t *, uintptr_t, bool, pte_t *pte);
+static void pt_mapping_update(as_t *, uintptr_t, bool, pte_t *pte);
 static void pt_mapping_make_global(uintptr_t, size_t);
 
@@ -60 +61 @@
         .mapping_remove = pt_mapping_remove,
         .mapping_find = pt_mapping_find,
+        .mapping_update = pt_mapping_update,
         .mapping_make_global = pt_mapping_make_global
 };
@@ -289 +291 @@
 }
 
-/** Find mapping for virtual page in hierarchical page tables.
- *
- * @param as     Address space to which page belongs.
- * @param page   Virtual page.
- * @param nolock True if the page tables need not be locked.
- *
- * @return NULL if there is no such mapping; entry from PTL3 describing
- *         the mapping otherwise.
- *
- */
-pte_t *pt_mapping_find(as_t *as, uintptr_t page, bool nolock)
+static pte_t *pt_mapping_find_internal(as_t *as, uintptr_t page, bool nolock)
 {
         ASSERT(nolock || page_table_locked(as));
@@ -334 +326 @@
         
         return &ptl3[PTL3_INDEX(page)];
+}
+
+/** Find mapping for virtual page in hierarchical page tables.
+ *
+ * @param as       Address space to which page belongs.
+ * @param page     Virtual page.
+ * @param nolock   True if the page tables need not be locked.
+ * @param[out] pte Structure that will receive a copy of the found PTE.
+ *
+ * @return True if the mapping was found, false otherwise.
+ */
+bool pt_mapping_find(as_t *as, uintptr_t page, bool nolock, pte_t *pte)
+{
+        pte_t *t = pt_mapping_find_internal(as, page, nolock);
+        if (t)
+                *pte = *t;
+        return t != NULL;
+}
+
+/** Update mapping for virtual page in hierarchical page tables.
+ *
+ * @param as       Address space to which page belongs.
+ * @param page     Virtual page.
+ * @param nolock   True if the page tables need not be locked.
+ * @param[in] pte  New PTE.
+ */
+void pt_mapping_update(as_t *as, uintptr_t page, bool nolock, pte_t *pte)
+{
+        pte_t *t = pt_mapping_find_internal(as, page, nolock);
+        if (!t)
+                panic("Updating non-existent PTE");     
+
+        ASSERT(PTE_VALID(t) == PTE_VALID(pte));
+        ASSERT(PTE_PRESENT(t) == PTE_PRESENT(pte));
+        ASSERT(PTE_GET_FRAME(t) == PTE_GET_FRAME(pte));
+        ASSERT(PTE_WRITABLE(t) == PTE_WRITABLE(pte));
+        ASSERT(PTE_EXECUTABLE(t) == PTE_EXECUTABLE(pte));
+
+        *t = *pte;
 }