Changes in kernel/genarch/src/mm/page_pt.c [e943ecf:de73242] in mainline

File:

• kernel/genarch/src/mm/page_pt.c (modified) (6 diffs)

kernel/genarch/src/mm/page_pt.c

@@ -89 +89 @@
                     PAGE_NOT_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
                     PAGE_WRITE);
+                /*
+                 * Make sure that a concurrent hardware page table walk or
+                 * pt_mapping_find() will see the new PTL1 only after it is
+                 * fully initialized.
+                 */
                 write_barrier();
                 SET_PTL1_PRESENT(ptl0, PTL0_INDEX(page));
@@ -103 +108 @@
                     PAGE_NOT_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
                     PAGE_WRITE);
+                /*
+                 * Make the new PTL2 visible only after it is fully initialized.
+                 */
                 write_barrier();
                 SET_PTL2_PRESENT(ptl1, PTL1_INDEX(page));       
@@ -117 +125 @@
                     PAGE_NOT_PRESENT | PAGE_USER | PAGE_EXEC | PAGE_CACHEABLE |
                     PAGE_WRITE);
+                /*
+                 * Make the new PTL3 visible only after it is fully initialized.
+                 */
                 write_barrier();
                 SET_PTL3_PRESENT(ptl2, PTL2_INDEX(page));
@@ -125 +136 @@
         SET_FRAME_ADDRESS(ptl3, PTL3_INDEX(page), frame);
         SET_FRAME_FLAGS(ptl3, PTL3_INDEX(page), flags | PAGE_NOT_PRESENT);
+        /*
+         * Make the new mapping visible only after it is fully initialized.
+         */
         write_barrier();
         SET_FRAME_PRESENT(ptl3, PTL3_INDEX(page));
@@ -296 +310 @@
 
 #if (PTL1_ENTRIES != 0)
+        /*
+         * Always read ptl2 only after we are sure it is present.
+         */
         read_barrier();
 #endif
@@ -304 +321 @@
 
 #if (PTL2_ENTRIES != 0)
+        /*
+         * Always read ptl3 only after we are sure it is present.
+         */
         read_barrier();
 #endif