[PATCH v3 04/11] arm64: use fixmap region for permanent FDT mapping

[Mark Rutland]

> I was wondering: this code now always maps the full 4 MB, also on 64k
> pages, even if in the majority of cases, the actual FDT is much
> smaller. Do you think there is a downside to that?

The two cases I can think of as problematic are when the FDT is in the
last 2M of RAM, or in a 2M region immediately before some carveout which
won't use MT_NORMAL attributes.

We could solve those by only mapping however many 2M chunks are
necessary, or we could keep the requirement that it fits within a
naturally-aligned 2M region for now.

I don't see that this should yield significant problems otherwise.

Mark.