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

["Mario Limonciello (AMD) (kernel.org)" <superm1@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?