[PATCH v3 RESEND 05/17] ARM: LPAE: support 64-bit virt_to_phys patching

On 9/24/2012 11:56 AM, Nicolas Pitre wrote:

On Mon, 24 Sep 2012, Catalin Marinas wrote:

quoted

On Fri, Sep 21, 2012 at 04:56:03PM +0100, Cyril Chemparathy wrote:

quoted

This patch adds support for 64-bit physical addresses in virt_to_phys()
patching.  This does not do real 64-bit add/sub, but instead patches in the
upper 32-bits of the phys_offset directly into the output of virt_to_phys.

So this assumes that for the kernel linear mapping, all the physical
addresses have the same upper 32-bit. That's a good optimisation but I
haven't seen this check when calculating lowmem in sanity_check_meminfo.
Someone may build platform with memory starting at 3GB and going across
the 4GB limit.

Good point.  We better get an early warning if that happens.

Thanks.

I'm thinking of splitting the bank at the 32-bit boundary in such an 
event, assuming that the remaining memory should be usable as highmem.

-- 
Thanks
- Cyril