CeDOS - Commit c61ba380

kernel: Memory holes fixed in paging subsystem CeDOS crashed frequently on real hardware, caused by uninitialized memory. With this and the previous commit, it seems to run very stable.
Celina Sophie Kalus
hello@celinakalus.de
Fri, 08 Dec 2023 21:46:25 +0100
1 files changed, 6 insertions(+), 3 deletions(-)
M kernel/mm/paging.c → kernel/mm/paging.c 
@@ -71,6 +71,8 @@ if (!is_present(page_dir[dir_index])) {
         // acquire new page table
         PHYS_ADDR new_page_table = get_free_page();
         page_dir[dir_index] = MAKE_PAGE_ENTRY(new_page_table, PAGE_TABLE_FLAGS);
+        inv_all_pages();
+        memset(page_table, 0, PAGE_SIZE);
     }
 
     // map page

@@ -95,6 +97,8 @@ if (!is_present(page_dir[dir_index])) {
         // acquire new page table
         void *new_page_table = get_free_page();
         page_dir[dir_index] = MAKE_PAGE_ENTRY(new_page_table, PAGE_TABLE_FLAGS);
+        inv_all_pages();
+        memset(page_table, 0, PAGE_SIZE);
     }
 
     // map page

@@ -126,9 +130,8 @@ uint32_t part_length = (offset + length <= PAGE_SIZE) ? length : PAGE_SIZE - offset;
 
         PRINT_DBG("src=%p dest=%p length=%i offset=%i plen=%i\n", src, dest, length, offset, part_length);
 
-        for (uint32_t i = 0; i < part_length; i++) {
-            ((uint8_t*)mount_dest)[offset + i] = ((uint8_t*)src)[i];
-        }
+        memset(mount_dest, 0, PAGE_SIZE);
+        memcpy((uint8_t*)(mount_dest) + offset, src, part_length);
 
         dest += part_length;
         src += part_length;