[RFC,PATCH] arm: use param address to establish params mapping

[Russell King - ARM Linux]

On Thu, Apr 01, 2010 at 10:59:44AM +0800, Jeremy Kerr wrote:
> Currently, __create_page_tables assumes that the boot params are within
> the first MB of physical memory, and creates a translation from the kernel
> direct mapping region based on this assumption.
> 
> Rather than guessing, use the atags/params address instead. This also
> means we don't have to rely on PHYS_ADDR to create the mapping.

As we still potentially have boot loaders which don't pass a valid value
in r2, can you please add some protection against random values being
passed rather than assuming that it always contains a valid value?