arm64: MPAM2_EL2 and MPAMHCR_EL2 are left UNKNOWN under arm64.nompam

[Fuad Tabba]

On Wed, 2 Sept 2026 at 16:27, Xi Ruoyao <xry111 at xry111.site> wrote:
>
> On Thu, 2026-08-27 at 09:41 +0100, Ben Horgan wrote:
> > > not, could the caveat go the other way round: arm64.nompam is for
> > > systems where firmware ignores MPAM, and should only be set on a
> > > machine that does not boot without it?
> >
> > Yes, seems fine.
>
> Sorry for the late reply.  This is indeed the original purpose for
> arm64.nompam, a dirty hack when we have no other ways to make the system
> boot.  If you think it causes an inconsistent state I'd not complain
> against adding a loud warning or something.

Thanks. After discussing it with Ben, I think the best option (or the
least bad option :)) seems to be documenting it [1]. I'll send that
soon.

Cheers,
/fuad

[1] https://lore.kernel.org/all/0b2c58d2-cc82-4c68-aaa2-83449d0b48c1@arm.com/

>
> --
> Xi Ruoyao <xry111 at xry111.site>