Re: [RFC 2/4] arch-topology: add a default implementation of store_cpu_topology()

From: Sudeep Holla
Date: Fri Jul 08 2022 - 10:00:51 EST

On Fri, Jul 08, 2022 at 11:57:05AM +0000, Conor.Dooley@xxxxxxxxxxxxx wrote:
> I did a little bit of poking in the git history.
> The last code touching the arm implementation was:
> 3102bc0e6ac7 ("arm64: topology: Stop using MPIDR for topology information")
> on Fri Oct 2 12:01:41 2020 +0100
> The introduction of arch-topology stuff to RISC-V was:
> 03f11f03dbfe ("RISC-V: Parse cpu topology during boot.")
> on Thu Jun 27 12:53:00 2019 -0700
> Backporting as far as v5.10 should be no real effort and I don't think
> to v5.4 that should be meaninfully harder. If 3102bc0e6ac7 hasn't been
> backported already, maybe it should be since it appears to have been
> fixing a problem too.

Thanks for doing the research and sorry for the noise earlier.

> Based on that, I think doing this the straightforward way in the first
> place is a better idea.
> I'll respin the series as:
> patch 1: Move arm64 to the generic implementation

I don't think the mpidr check we have there is of much use IMO. You can
drop that and see if arm64 maintainers and/or others agree. As you have
already figured, since 3102bc0e6ac7 we are not using MPIDR and the one
check we have is optional IMO. So you can either drop it or keep it as
in your RFC and then post updates.