Re: Question on the five-level page table support patches

[David Miller]

From: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx>
Date: Mon, 24 Apr 2017 22:37:40 +0200

> Would be really nice to able to have a canonical solution for this issue,
> it's been biting us on SPARC for quite a while now due to the fact that
> virtual address space has been 52 bits on SPARC for a while now.

It's going to break again with things like ADI which encode protection
keys in the high bits of the 64-bit virtual address.

Reallly, it would be nice if these tags were instead encoded in the
low bits of suitably aligned memory allocations but I am sure it's to
late to do that now.