Changeset 346b12a2 in mainline for kernel/genarch/src/mm/page_pt.c

Timestamp:

2016-08-31T17:51:04Z (9 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

fb63c06

Parents:

38dc82d

Message:

Add page_mapping_update()

page_mapping_update() can be used to safely update the accessed and dirty
bits of a PTE in the actual page tables.

File:

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

kernel/genarch/src/mm/page_pt.c

@@ -54 +54 @@
 static void pt_mapping_remove(as_t *, uintptr_t);
 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 @@
 }
 
+static pte_t *pt_mapping_find_internal(as_t *as, uintptr_t page, bool nolock)
+{
+        ASSERT(nolock || page_table_locked(as));
+
+        pte_t *ptl0 = (pte_t *) PA2KA((uintptr_t) as->genarch.page_table);
+        if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
+                return NULL;
+
+        read_barrier();
+        
+        pte_t *ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
+        if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
+                return NULL;
+
+#if (PTL1_ENTRIES != 0)
+        /*
+         * Always read ptl2 only after we are sure it is present.
+         */
+        read_barrier();
+#endif
+        
+        pte_t *ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
+        if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
+                return NULL;
+
+#if (PTL2_ENTRIES != 0)
+        /*
+         * Always read ptl3 only after we are sure it is present.
+         */
+        read_barrier();
+#endif
+        
+        pte_t *ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
+        
+        return &ptl3[PTL3_INDEX(page)];
+}
+
 /** Find mapping for virtual page in hierarchical page tables.
  *
@@ -300 +339 @@
 bool pt_mapping_find(as_t *as, uintptr_t page, bool nolock, pte_t *pte)
 {
-        ASSERT(nolock || page_table_locked(as));
-
-        pte_t *ptl0 = (pte_t *) PA2KA((uintptr_t) as->genarch.page_table);
-        if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT)
-                return false;
-
-        read_barrier();
-        
-        pte_t *ptl1 = (pte_t *) PA2KA(GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page)));
-        if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT)
-                return false;
-
-#if (PTL1_ENTRIES != 0)
-        /*
-         * Always read ptl2 only after we are sure it is present.
-         */
-        read_barrier();
-#endif
-        
-        pte_t *ptl2 = (pte_t *) PA2KA(GET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page)));
-        if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT)
-                return false;
-
-#if (PTL2_ENTRIES != 0)
-        /*
-         * Always read ptl3 only after we are sure it is present.
-         */
-        read_barrier();
-#endif
-        
-        pte_t *ptl3 = (pte_t *) PA2KA(GET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page)));
-        
-        *pte = ptl3[PTL3_INDEX(page)];
-        return true;
+        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;
 }