linux-kernel - Re: [PATCH linux] aspeed: pinctrl: Allow disabling Port D and Port E loopback mode

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] [day] [month] [year] [list]

Date:   Thu, 23 Feb 2017 15:45:55 +0100
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Rick Altherr <raltherr@...gle.com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        OpenBMC Maillist <openbmc@...ts.ozlabs.org>,
        Joel Stanley <joel@....id.au>, Andrew Jeffery <andrew@...id.au>
Subject: Re: [PATCH linux] aspeed: pinctrl: Allow disabling Port D and Port E
 loopback mode

On Wed, Feb 15, 2017 at 7:09 AM, Rick Altherr <raltherr@...gle.com> wrote:

> Port D and port E GPIO loopback modes are commonly enabled via hardware
> straps for use with front-panel buttons.  When the BMC is powered
> off or fails to boot, the front-panel buttons are directly connected to
> the host chipset via the loopback to allow direct power-on and reset
> control. Once the BMC has booted, the loopback mode must be disabled for
> the BMC to take over control of host power-on and reset.
>
> Disabling these loopback modes requires writing to the hardware strap
> register which violates the current design of assuming the system
> designer chose the strap settings for a specific reason and they should
> be treated as read-only. Only the two bits of the strap register related
> to these loopback modes are allowed to be written and comments have been
> added to explain why.
>
> Signed-off-by: Rick Altherr <raltherr@...gle.com>

Patch applied with the ACKs for v4.12.

Yours,
Linus Walleij