Detect presence of LPAE when not running an LPAE kernel?

[Will Deacon]

On Fri, Oct 04, 2013 at 05:23:22PM +0100, Ian Campbell wrote:
> On Fri, 2013-10-04 at 17:09 +0100, Will Deacon wrote:
> > On Fri, Oct 04, 2013 at 08:15:08AM +0100, Ian Campbell wrote:
> > > Should/do we expose the actual CPU LPAE capability somewhere?
> > 
> > That's the whole point of the HWCAP.
> 
> Russell was saying it actually related to the presence of strd/ldrd, how
> tightly is that tied to the presence of LPAE in theory? In practise it
> seems closely related...

Take a gander at the code: we're checking the VMSA version in one of the
MMFR registers. LPAE implies atomic ldrd/strd, so that's what this is all
about (and why it ended up being called "lpae").

In short, this HWCAP does exactly what you want.

Will