x86: mark the .rodata section also NX
The .rodata section shouldn't just be read-only,
but also non-executable. This is free since we've broken
up the 2MB page already anyway.
also update test_nx to check for this.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 3a98d6f..9b61c75 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -591,10 +591,17 @@
if (end <= start)
return;
- set_memory_ro(start, (end - start) >> PAGE_SHIFT);
printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
(end - start) >> 10);
+ set_memory_ro(start, (end - start) >> PAGE_SHIFT);
+
+ /*
+ * The rodata section (but not the kernel text!) should also be
+ * not-executable.
+ */
+ start = ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
+ set_memory_nx(start, (end - start) >> PAGE_SHIFT);
rodata_test();