Changeset c72dc15 in mainline

Timestamp:

2011-12-14T23:57:25Z (13 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

3b71e84d

Parents:

1b478f6

Message:

When unmapping pages, do not cleanup the first level page tables
in the subtree which corresponds to the kernel non-identity mapping.

File:

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

kernel/genarch/src/mm/page_pt.c

@@ -39 +39 @@
 #include <mm/page.h>
 #include <mm/frame.h>
+#include <mm/km.h>
 #include <mm/as.h>
 #include <arch/mm/page.h>
@@ -153 +154 @@
         
         /*
-         * Second, free all empty tables along the way from PTL3 down to PTL0.
-         *
+         * Second, free all empty tables along the way from PTL3 down to PTL0
+         * except those needed for sharing the kernel non-identity mappings.
          */
         
@@ -171 +172 @@
                 /*
                  * PTL3 is empty.
-                 * Release the frame and remove PTL3 pointer from preceding table.
-                 *
-                 */
-                frame_free(KA2PA((uintptr_t) ptl3));
+                 * Release the frame and remove PTL3 pointer from the parent
+                 * table.
+                 */
 #if (PTL2_ENTRIES != 0)
                 memsetb(&ptl2[PTL2_INDEX(page)], sizeof(pte_t), 0);
@@ -180 +180 @@
                 memsetb(&ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
 #else
+                if (km_is_non_identity(page))
+                        return;
+
                 memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
 #endif
+                frame_free(KA2PA((uintptr_t) ptl3));
         } else {
                 /*
@@ -204 +208 @@
                 /*
                  * PTL2 is empty.
-                 * Release the frame and remove PTL2 pointer from preceding table.
-                 *
-                 */
-                frame_free(KA2PA((uintptr_t) ptl2));
+                 * Release the frame and remove PTL2 pointer from the parent
+                 * table.
+                 */
 #if (PTL1_ENTRIES != 0)
                 memsetb(&ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0);
 #else
+                if (km_is_non_identity(page))
+                        return;
+
                 memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
 #endif
+                frame_free(KA2PA((uintptr_t) ptl2));
         } else {
                 /*
@@ -236 +243 @@
                 /*
                  * PTL1 is empty.
-                 * Release the frame and remove PTL1 pointer from preceding table.
-                 *
-                 */
+                 * Release the frame and remove PTL1 pointer from the parent
+                 * table.
+                 */
+                if (km_is_non_identity(page))
+                        return;
+
+                memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
                 frame_free(KA2PA((uintptr_t) ptl1));
-                memsetb(&ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0);
         }
 #endif /* PTL1_ENTRIES != 0 */