linux-kernel - Re: [PATCH v2] watchdog: sp5100_tco: Add "action" module parameter

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20220922173635.GJ18783@rfwz62>
Date:   Thu, 22 Sep 2022 11:36:35 -0600
From:   rwright@....com
To:     Vladimir Panteleev <git@...dimir.panteleev.md>
Cc:     Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>,
        linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] watchdog: sp5100_tco: Add "action" module parameter

On Tue, Sep 20, 2022 at 09:27:21AM +0000, Vladimir Panteleev wrote:
> Allow configuring the "action" bit, as documented in [1].
> 
> Previously, the only action supported by this module was to reset the
> system (0).  It can now be configured to power off (1) instead.
> 
> [1]: https://www.amd.com/system/files/TechDocs/44413.pdf

The referenced AMD document 44413 is over 10 years old, and I'm
concerned when I try to line that document up against the newer versions
that are implemented in AMD's EPYC processors, that the bit being
manipulated as SP5100_WDT_ACTION_RESET is effectively reserved in the
newer references, for example:

   https://www.amd.com/system/files/TechDocs/55772-A1-PUB.zip

Is Core::X86::Msr::CpuWdtCfg in the newer document is the same as
WatchDogControl in the cited 44413.pdf? If so, then I would point out
that bit 2 is now included in what is called, CpuWdtTimeBase where
values 2-3H are reserved,  meaning bit 2 effectively must be zero.

-- 
Randy Wright            Hewlett Packard Enterprise
Phone: (970) 898-0998   Mail: rwright@....com