Subject: Re: powerpc/64: Reclaim CPU_FTR_SUBCORE

From: Michael Ellerman <[email-masked]>
Date: Thu, 1 Jun 2017 23:31:09 +1000 (AEST)

On Mon, 2017-05-29 at 01:53:10 UTC, Michael Ellerman wrote:
> We are running low on CPU feature bits, so we only want to use them when
> it's really necessary.
> 
> CPU_FTR_SUBCORE is only used in one place, and only in C, so we don't
> need it in order to make asm patching work. It can only be set on
> "Power8" CPUs, which in practice means POWER8, POWER8E and POWER8NVL.
> There are no plans to implement it on future CPUs, but if there ever
> were we could retrofit it then.
> 
> Although KVM uses subcores, it never looks at the CPU feature, it either
> looks at the ISA level or the threads_per_subcore value.
> 
> So drop the CPU feature and do a PVR check instead. Drop the device tree
> "subcore" feature as we no longer support doing anything with it, and we
> will drop it from skiboot too.
> 
> Signed-off-by: Michael Ellerman <[email-masked]>
> Acked-by: Balbir Singh <[email-masked]>

Applied to powerpc fixes.

https://git.kernel.org/powerpc/c/0e5e7f5e9700661c3ddd95501743fb

cheers