Re: [PATCH 5/6] arm64: errata: Add QCOM_KRYO_5XX_GOLD to the spectre_bhb_k24_list

[Doug Anderson]

Hi,

On Mon, Dec 9, 2024 at 3:07 PM Dmitry Baryshkov
<dmitry.baryshkov@xxxxxxxxxx> wrote:
>
> On Mon, Dec 09, 2024 at 09:43:15AM -0800, Douglas Anderson wrote:
> > Qualcomm Kryo 500-series Gold cores appear to have a derivative of an
> > ARM Cortex A77 in them. Since A77 needs Spectre mitigation then the
> > Kyro 500-series Gold cores also should need Spectre mitigation.
> >
> > Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> > ---
> > Yes. I know. This patch DOESN'T COMPILE because
> > MIDR_QCOM_KRYO_5XX_GOLD is not defined. That value needs to come from
> > Qualcomm or from testing on hardware, which I don't have. Qualcomm
> > needs to chime in to confirm that this Spectre mitigation is correct
> > anyway, though. I'm including this patch so it's obvious that I think
> > these cores also need the mitigation.
>
> Kryo 5xx (SM8250) identify themselves as 0x41/0xd0d (Gold, Prime) and
> 0x51/0x805 (Silver)

Interesting. So the Gold/Prime are actually IDing themselves as
straight Cortex A77. The Silver is IDing itself the same as
KRYO_4XX_SILVER. ...so in that sense there's nothing to do here for
those cores.


-Doug