Re: [PATCH] x86/CPU/AMD: Prevent reset reasons from being retained among boots

[Mario Limonciello (AMD) (kernel.org)]

On 9/16/2025 9:02 AM, Borislav Petkov wrote:
> On Sat, Sep 13, 2025 at 10:42:45PM +0800, Rong Zhang wrote:
> > The S5_RESET_STATUS register is parsed on boot and printed to kmsg.
> > However, this could sometimes be misleading and lead to users wasting a
> > lot of time on meaningless debugging for two reasons:
> >
> > * Some bits are never cleared by hardware. It's the software's
> > responsibility to clear them as per the Processor Programming Reference
> > (see Link:).
> >
> > * Some rare hardware-initiated platform resets do not update the
> > register at all.
> >
> > In both cases, a previous reboot could leave its trace in the register,
> > resulting in users seeing unrelated reboot reasons while debugging
> > random reboots afterward.
>
> Just a heads-up: we're figuring out internally what the right thing to do here
> would be.
>
> Stay tuned.
>
> Thx.

The internal conversation points in the direction of your patch makes sense.

But I don't really see a lot of value in re-reading and printing a debug 
message about what was cleared and what's still there.  Do you see a 
reason to keep that around?