On 01/30/2013 01:25 PM, Yinghai Lu wrote:
>
> +static void clean_boot_params(unsigned char *real_mode, unsigned long size)
> +{
> + unsigned long end;
> +
> + /* clear value before header */
> + memset(real_mode, 0, 0x1f1);
> + /* clear value after setup_header */
> + end = *(real_mode + 0x201);
real_mode[0x201] might be clearer...
> + end += 0x202;
> + if (end < size)
> + memset(real_mode + end, 0, size - end);
> +}
You don't actually need the test... the value is inherently smaller than
0x301 which is less than the size.
That being said, if you want to sanity-check it you can check that the
value is in a sensible range -- the permitted range is 0x22 to 0x7f
inclusive, corresponding to a total end value of 0x224 to 0x281.
-hpa
