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

From: Borislav Petkov

Date: Mon Oct 06 2025 - 09:31:48 EST


On Tue, Sep 30, 2025 at 06:18:30PM +0800, Rong Zhang wrote:
> A user may feel confused: Two bits are set, but only one reason is
> reported. Hmm... Is there a hidden failure?

Why would you assume that 1 set bit == 1 failure reason?

> Unless the user has read the PPR, it's hard to realize BIT(11) is
> already set in the reset value. The debug message is here to help:
>
> Cleared system reset reasons [0x08000800 => 0x00000800]
> ^ ^ ^ ^
>
> Now the user realizes that BIT(11) has nothing to do with reboot
> reasons.
>
> This was literally the confusion I experienced. I had to take some time
> looking for an appropriate public PPR and reading the PPR before
> realizing this fact.

Please explain in detail what confusion you were experiencing so that we can
address it properly.

Thx.

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette