[PATCH v2 4/6] ARM: mm: LPAE: Correct virt_to_phys patching for 64 bit physical addresses

Russell King - ARM Linux linux at arm.linux.org.uk
Sat Aug 3 10:09:48 EDT 2013

On Sat, Aug 03, 2013 at 03:05:44PM +0100, Russell King - ARM Linux wrote:
> On Sat, Aug 03, 2013 at 06:17:29PM +0530, Sricharan R wrote:
> >   I started with this kind of augmenting with the immediate operand
> >   while starting V2. But the problem was, we do the runtime patching twice.
> It might be much better to do this only once, and instead of having the
> early code overwrite the page table in use, create a new page table with
> all the correct page table entries in and switch to that.

Note: we still need to do a certain amount of modification of the existing
page table so that we _can_ perform such a switch on all our CPUs - that
is, ensuring that the region for flushing the CPU caches on processors
which need it is properly mapped.

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