Changes in kernel/genarch/src/mm/page_pt.c [de73242:346b12a2] in mainline

File:

• kernel/genarch/src/mm/page_pt.c (modified) (12 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
 };
@@ -82 +84 @@
         
         if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) {
-                pte_t *newpt = (pte_t *) frame_alloc(PTL1_SIZE,
-                    FRAME_LOWMEM | FRAME_KA);
-                memsetb(newpt, FRAME_SIZE << PTL1_SIZE, 0);
+                pte_t *newpt = (pte_t *)
+                    PA2KA(frame_alloc(PTL1_FRAMES, FRAME_LOWMEM, PTL1_SIZE - 1));
+                memsetb(newpt, PTL1_SIZE, 0);
                 SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(page), KA2PA(newpt));
                 SET_PTL1_FLAGS(ptl0, PTL0_INDEX(page),
@@ -101 +103 @@
         
         if (GET_PTL2_FLAGS(ptl1, PTL1_INDEX(page)) & PAGE_NOT_PRESENT) {
-                pte_t *newpt = (pte_t *) frame_alloc(PTL2_SIZE,
-                    FRAME_LOWMEM | FRAME_KA);
-                memsetb(newpt, FRAME_SIZE << PTL2_SIZE, 0);
+                pte_t *newpt = (pte_t *)
+                    PA2KA(frame_alloc(PTL2_FRAMES, FRAME_LOWMEM, PTL2_SIZE - 1));
+                memsetb(newpt, PTL2_SIZE, 0);
                 SET_PTL2_ADDRESS(ptl1, PTL1_INDEX(page), KA2PA(newpt));
                 SET_PTL2_FLAGS(ptl1, PTL1_INDEX(page),
@@ -112 +114 @@
                  */
                 write_barrier();
-                SET_PTL2_PRESENT(ptl1, PTL1_INDEX(page));       
+                SET_PTL2_PRESENT(ptl1, PTL1_INDEX(page));
         }
         
@@ -118 +120 @@
         
         if (GET_PTL3_FLAGS(ptl2, PTL2_INDEX(page)) & PAGE_NOT_PRESENT) {
-                pte_t *newpt = (pte_t *) frame_alloc(PTL3_SIZE,
-                    FRAME_LOWMEM | FRAME_KA);
-                memsetb(newpt, FRAME_SIZE << PTL3_SIZE, 0);
+                pte_t *newpt = (pte_t *)
+                    PA2KA(frame_alloc(PTL3_FRAMES, FRAME_LOWMEM, PTL2_SIZE - 1));
+                memsetb(newpt, PTL2_SIZE, 0);
                 SET_PTL3_ADDRESS(ptl2, PTL2_INDEX(page), KA2PA(newpt));
                 SET_PTL3_FLAGS(ptl2, PTL2_INDEX(page),
@@ -180 +182 @@
          * Destroy the mapping.
          * Setting to PAGE_NOT_PRESENT is not sufficient.
-         */
+         * But we need SET_FRAME for possible PT coherence maintenance.
+         * At least on ARM.
+         */
+        //TODO: Fix this inconsistency
+        SET_FRAME_FLAGS(ptl3, PTL3_INDEX(page), PAGE_NOT_PRESENT);
         memsetb(&ptl3[PTL3_INDEX(page)], sizeof(pte_t), 0);
         
@@ -215 +221 @@
                 memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
 #endif
-                frame_free(KA2PA((uintptr_t) ptl3));
+                frame_free(KA2PA((uintptr_t) ptl3), PTL3_FRAMES);
         } else {
                 /*
@@ -249 +255 @@
                 memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
 #endif
-                frame_free(KA2PA((uintptr_t) ptl2));
+                frame_free(KA2PA((uintptr_t) ptl2), PTL2_FRAMES);
         } else {
                 /*
@@ -280 +286 @@
 
                 memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
-                frame_free(KA2PA((uintptr_t) ptl1));
+                frame_free(KA2PA((uintptr_t) ptl1), PTL1_FRAMES);
         }
 #endif /* PTL1_ENTRIES != 0 */
 }
 
-/** 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));
@@ -330 +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;
 }
 
@@ -359 +394 @@
  * @param size Size in bytes defining the range of PTL0 entries that will be
  *             altered by this function.
+ *
  */
 void pt_mapping_make_global(uintptr_t base, size_t size)
 {
+        ASSERT(size > 0);
+        
         uintptr_t ptl0 = PA2KA((uintptr_t) AS_KERNEL->genarch.page_table);
         uintptr_t ptl0_step = ptl0_step_get();
-        size_t order;
-        uintptr_t addr;
-
+        size_t frames;
+        
 #if (PTL1_ENTRIES != 0)
-        order = PTL1_SIZE;
+        frames = PTL1_FRAMES;
 #elif (PTL2_ENTRIES != 0)
-        order = PTL2_SIZE;
+        frames = PTL2_FRAMES;
 #else
-        order = PTL3_SIZE;
+        frames = PTL3_FRAMES;
 #endif
-
-        ASSERT(size > 0);
-
-        for (addr = ALIGN_DOWN(base, ptl0_step); addr - 1 < base + size - 1;
+        
+        for (uintptr_t addr = ALIGN_DOWN(base, ptl0_step);
+            addr - 1 < base + size - 1;
             addr += ptl0_step) {
-                uintptr_t l1;
-
-                l1 = (uintptr_t) frame_alloc(order, FRAME_KA | FRAME_LOWMEM);
-                memsetb((void *) l1, FRAME_SIZE << order, 0);
+                if (GET_PTL1_ADDRESS(ptl0, PTL0_INDEX(addr))) {
+                        ASSERT(overlaps(addr, ptl0_step,
+                            config.identity_base, config.identity_size));
+
+                        /*
+                         * This PTL0 entry also maps the kernel identity region,
+                         * so it is already global and initialized.
+                         */
+                        continue;
+                }
+
+                uintptr_t l1 = PA2KA(frame_alloc(frames, FRAME_LOWMEM, 0));
+                memsetb((void *) l1, FRAMES2SIZE(frames), 0);
                 SET_PTL1_ADDRESS(ptl0, PTL0_INDEX(addr), KA2PA(l1));
                 SET_PTL1_FLAGS(ptl0, PTL0_INDEX(addr),