Changeset 11e9061d in mainline

Timestamp:

2008-06-11T19:00:55Z (16 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

80dabb8d

Parents:

f1fa2657

Message:

Issue a memory barrier after modifying a page table mapping in order to
prevent memory prefetching.

File:

• kernel/generic/src/mm/page.c (modified) (8 diffs)

kernel/generic/src/mm/page.c

@@ -46 +46 @@
 #include <mm/as.h>
 #include <mm/frame.h>
+#include <arch/barrier.h>
 #include <arch/types.h>
 #include <arch/asm.h>
@@ -66 +67 @@
  * of page boundaries.
  *
- * @param s Address of the structure.
- * @param size Size of the structure.
+ * @param s             Address of the structure.
+ * @param size          Size of the structure.
  */
 void map_structure(uintptr_t s, size_t size)
@@ -77 +78 @@
 
         for (i = 0; i < cnt; i++)
-                page_mapping_insert(AS_KERNEL, s + i * PAGE_SIZE, s + i * PAGE_SIZE, PAGE_NOT_CACHEABLE | PAGE_WRITE);
+                page_mapping_insert(AS_KERNEL, s + i * PAGE_SIZE,
+                    s + i * PAGE_SIZE, PAGE_NOT_CACHEABLE | PAGE_WRITE);
 
+        /* Repel prefetched accesses to the old mapping. */
+        memory_barrier();
 }
 
@@ -88 +92 @@
  * The page table must be locked and interrupts must be disabled.
  *
- * @param as Address space to wich page belongs.
- * @param page Virtual address of the page to be mapped.
- * @param frame Physical address of memory frame to which the mapping is done.
- * @param flags Flags to be used for mapping.
+ * @param as            Address space to wich page belongs.
+ * @param page          Virtual address of the page to be mapped.
+ * @param frame         Physical address of memory frame to which the mapping is
+ *                      done.
+ * @param flags         Flags to be used for mapping.
  */
 void page_mapping_insert(as_t *as, uintptr_t page, uintptr_t frame, int flags)
@@ -99 +104 @@
         
         page_mapping_operations->mapping_insert(as, page, frame, flags);
+        
+        /* Repel prefetched accesses to the old mapping. */
+        memory_barrier();
 }
 
@@ -109 +117 @@
  * The page table must be locked and interrupts must be disabled.
  *
- * @param as Address space to wich page belongs.
- * @param page Virtual address of the page to be demapped.
+ * @param as            Address space to wich page belongs.
+ * @param page          Virtual address of the page to be demapped.
  */
 void page_mapping_remove(as_t *as, uintptr_t page)
@@ -118 +126 @@
         
         page_mapping_operations->mapping_remove(as, page);
+
+        /* Repel prefetched accesses to the old mapping. */
+        memory_barrier();
 }
 
@@ -126 +137 @@
  * The page table must be locked and interrupts must be disabled.
  *
- * @param as Address space to wich page belongs.
- * @param page Virtual page.
+ * @param as            Address space to wich page belongs.
+ * @param page          Virtual page.
  *
- * @return NULL if there is no such mapping; requested mapping otherwise.
+ * @return              NULL if there is no such mapping; requested mapping
+ *                      otherwise.
  */
 pte_t *page_mapping_find(as_t *as, uintptr_t page)