Re: [PATCH 3/3] arm64: cpuinfo: display product info in /proc/cpuinfo

[Mark Rutland]

Hi,

On Wed, Sep 27, 2017 at 11:42:07AM +0100, Robin Murphy wrote:
> On 26/09/17 23:23, Al Stone wrote:
> > +			seq_printf(m, ", ARM 8.%d (r%dp%d) CPU",
> > +				   MIDR_VARIANT(midr),
> > +				   MIDR_VARIANT(midr),
> > +				   MIDR_REVISION(midr));
> 
> What is "ARM 8.1" meant to infer for, say, a typical Cortex-A57?

Just to make Robin's point a little clearer, MIDR_EL1.Variant is
IMPLEMENTATION DEFINED, and doesn't describe the ARMv8.x architecture
revision.

For example, on Cortex A57 is contains the major revision number of the
CPU, and is 1 for any r1pY Cortex-A57 (e.g. those on Juno R1).

For better or worse, the architecture provides us no mechanism to
determine the architecture revision.

Thanks,
Mark.