x86, realmode: Set permission for real mode pages

Set proper permissions for rodata, text and data, removing the
realmode trampoline area as a remaining RWX memory mapping in the
kernel.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@intel.com>
Link: http://lkml.kernel.org/r/1336501366-28617-8-git-send-email-jarkko.sakkinen@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/realmode.c

@@ -86,7 +86,21 @@ static int __init set_real_mode_permissions(void)
 		PAGE_ALIGN(real_mode_header.end) -
 		__pa(real_mode_base);
 
-	set_memory_x((unsigned long) real_mode_base, all_size >> PAGE_SHIFT);
+	size_t ro_size =
+		PAGE_ALIGN(real_mode_header.ro_end) -
+		__pa(real_mode_base);
+
+	size_t text_size =
+		PAGE_ALIGN(real_mode_header.ro_end) -
+		real_mode_header.text_start;
+
+	unsigned long text_start =
+		(unsigned long) __va(real_mode_header.text_start);
+
+	set_memory_nx((unsigned long) real_mode_base, all_size >> PAGE_SHIFT);
+	set_memory_ro((unsigned long) real_mode_base, ro_size >> PAGE_SHIFT);
+	set_memory_x((unsigned long) text_start, text_size >> PAGE_SHIFT);
+
 	return 0;
 }