linux-kernel - Re: [PATCH v11 6/7] power: reset: add PSCR NVMEM Driver for Recording Power State Change Reasons

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3135893.lGaqSPkdTl@fedora-2.fritz.box>
Date: Fri, 20 Jun 2025 17:56:01 +0200
From: Francesco Valla <francesco@...la.it>
To: Sebastian Reichel <sre@...nel.org>,
 Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
 Benson Leung <bleung@...omium.org>, Tzung-Bi Shih <tzungbi@...nel.org>,
 Daniel Lezcano <daniel.lezcano@...aro.org>,
 Oleksij Rempel <o.rempel@...gutronix.de>
Cc: Oleksij Rempel <o.rempel@...gutronix.de>, kernel@...gutronix.de,
 linux-kernel@...r.kernel.org, Liam Girdwood <lgirdwood@...il.com>,
 Mark Brown <broonie@...nel.org>, "Rafael J. Wysocki" <rafael@...nel.org>,
 Zhang Rui <rui.zhang@...el.com>, Lukasz Luba <lukasz.luba@....com>,
 linux-pm@...r.kernel.org, Søren Andersen <san@...v.dk>,
 Guenter Roeck <groeck@...omium.org>,
 Matti Vaittinen <mazziesaccount@...il.com>,
 Ahmad Fatoum <a.fatoum@...gutronix.de>,
 Andrew Morton <akpm@...ux-foundation.org>, chrome-platform@...ts.linux.dev
Subject:
 Re: [PATCH v11 6/7] power: reset: add PSCR NVMEM Driver for Recording Power
 State Change Reasons

Hi Oleksij,

On Wednesday, 18 June 2025 at 14:02:54 Oleksij Rempel <o.rempel@...gutronix.de> wrote:
> This driver utilizes the Power State Change Reasons Recording (PSCRR)
> framework to store specific power state change information, such as
> shutdown or reboot reasons, into a designated non-volatile memory
> (NVMEM) cell.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@...gutronix.de>
> ---
> changes v6:
> - rename pscr_reason to psc_reason
> changes v5:
> - avoid a build against NVMEM=m
> changes v4:
> - remove devicetree dependencies
> ---
>  drivers/power/reset/Kconfig       |  22 +++
>  drivers/power/reset/Makefile      |   1 +
>  drivers/power/reset/pscrr-nvmem.c | 254 ++++++++++++++++++++++++++++++
>  3 files changed, 277 insertions(+)
>  create mode 100644 drivers/power/reset/pscrr-nvmem.c
> 

Tested-by: Francesco Valla <francesco@...la.it>

I tested this on a i.MX93 FRDM using the on-board EEPROM as storage and
a single-byte cell. Unfortunately, the on-board RTC does not have a
scratchpad.

PSCR was set in two different ways during subsequent tests:

 - manually from userspace
 - simulating a over-temperature condition through the emul_temp sysfs

In both cases, it was re-read correctly after reboot.

This will be very useful to detect and debug anomalous shutdowns or
reboots on the field.

Thank you!

Regards,
Francesco