Changeset fb84455 in mainline for generic

Timestamp:

2006-05-27T13:35:32Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

0ee077ee

Parents:

6bf18fa

Message:

Update page fault handlers to distinguish between different access modes that had caused the page fault.

Location:

generic

Files:

• include/mm/as.h (modified) (1 diff)
• src/lib/elf.c (modified) (1 diff)
• src/mm/as.c (modified) (3 diffs)

generic/include/mm/as.h

@@ -146 +146 @@
 extern int as_area_get_flags(as_area_t *area);
 extern void as_set_mapping(as_t *as, __address page, __address frame);
+extern bool as_area_check_access(as_area_t *area, pf_access_t access);
 extern int as_page_fault(__address page, pf_access_t access, istate_t *istate);
 extern void as_switch(as_t *old, as_t *new);

generic/src/lib/elf.c

@@ -236 +236 @@
         __address base, frame;
         index_t i;
+
+        if (!as_area_check_access(area, access))
+                return AS_PF_FAULT;
 
         ASSERT((addr >= entry->p_vaddr) && (addr < entry->p_vaddr + entry->p_memsz));

generic/src/mm/as.c

@@ -633 +633 @@
 }
 
+/** Check access mode for address space area.
+ *
+ * The address space area must be locked prior to this call.
+ *
+ * @param area Address space area.
+ * @param access Access mode.
+ *
+ * @return False if access violates area's permissions, true otherwise.
+ */
+bool as_area_check_access(as_area_t *area, pf_access_t access)
+{
+        int flagmap[] = {
+                [PF_ACCESS_READ] = AS_AREA_READ,
+                [PF_ACCESS_WRITE] = AS_AREA_WRITE,
+                [PF_ACCESS_EXEC] = AS_AREA_EXEC
+        };
+
+        if (!(area->flags & flagmap[access]))
+                return false;
+        
+        return true;
+}
+
 /** Handle page fault within the current address space.
  *
@@ -699 +722 @@
         if ((pte = page_mapping_find(AS, page))) {
                 if (PTE_PRESENT(pte)) {
-                        page_table_unlock(AS, false);
-                        mutex_unlock(&area->lock);
-                        mutex_unlock(&AS->lock);
-                        return AS_PF_OK;
+                        if (((access == PF_ACCESS_READ) && PTE_READABLE(pte)) ||
+                                (access == PF_ACCESS_WRITE && PTE_WRITABLE(pte)) ||
+                                (access == PF_ACCESS_EXEC && PTE_EXECUTABLE(pte))) {
+                                page_table_unlock(AS, false);
+                                mutex_unlock(&area->lock);
+                                mutex_unlock(&AS->lock);
+                                return AS_PF_OK;
+                        }
                 }
         }
@@ -1496 +1523 @@
         __address frame;
 
+        if (!as_area_check_access(area, access))
+                return AS_PF_FAULT;
+
         if (area->sh_info) {
                 btree_node_t *leaf;