Re: [PATCH] arm64/efi: remove spurious WARN_ON for !4K kernels

[Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>]

On Fri, Jun 17, 2016 at 10:16:01PM +0100, Matt Fleming wrote:
> On Fri, 03 Jun, at 11:00:40AM, Will Deacon wrote:
> > 
> > Mark, Jeremy?
> > 
> > I've kept this patch marked as unread, but it's not clear to me (a) how
> > urgent it is (b) what tree it should go through and (c) whether it's the
> > right thing to do!
> 
> Ping? Anyone got an update here?

Sorry, I'd been meaning to come back to this.

As Ard noted, there are serious cases that this detects which we cannot
handle, and a WARN_ON for those is appropriate.

For the alignment of regions as required for permissions, I believe we
need clarification in the spec, and in the mean time I think we should
keep the WARN_ON.

To accurately report problems with differing attributes within a
(kernel) page, we need more comprehensive checks on the EFI memory map,
and potentially in some cases where we handle things dynamically at run
time. I haven't had the chance to delve into those yet.

So I guess for the timebeing this should stay as a WARN_ON, even if in
some cases it is spurious.

Thanks,
Mark.