linux-kernel - Re: [RFC PATCH 0/5] Add NVMEM driver for i.MX93 OTP access through ELE

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]

Message-ID: <af16a67d-5b51-4310-91f7-67e8e956a880@kontron.de>
Date: Tue, 22 Apr 2025 09:37:19 +0200
From: Frieder Schrempf <frieder.schrempf@...tron.de>
To: Arnd Bergmann <arnd@...db.de>, Frieder Schrempf <frieder@...s.de>,
 Peng Fan <peng.fan@....com>, Pankaj Gupta <pankaj.gupta@....com>,
 linux-arm-kernel@...ts.infradead.org, Conor Dooley <conor+dt@...nel.org>,
 devicetree@...r.kernel.org, imx@...ts.linux.dev,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, linux-kernel@...r.kernel.org,
 Rob Herring <robh@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>,
 Shawn Guo <shawnguo@...nel.org>,
 Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Cc: Fabio Estevam <festevam@...il.com>, Frank Li <Frank.Li@....com>,
 Geert Uytterhoeven <geert+renesas@...der.be>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Pengutronix Kernel Team <kernel@...gutronix.de>,
 Rafał Miłecki <rafal@...ecki.pl>,
 Shengjiu Wang <shengjiu.wang@....com>, Shenwei Wang <shenwei.wang@....com>,
 Xu Yang <xu.yang_2@....com>,
 Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Subject: Re: [RFC PATCH 0/5] Add NVMEM driver for i.MX93 OTP access through
 ELE

Am 22.04.25 um 08:40 schrieb Arnd Bergmann:
> On Wed, Apr 16, 2025, at 16:26, Frieder Schrempf wrote:
> 
>> Therefore I implemented a simple driver that uses the ELE S400 API only, as the
>> FSB access (1) doesn't provide any benefits except for that it doesn't depend
>> on the ELE firmware being available. This is used by us downstream.
>>
>> For the upstream solution I would like to have some feedback on how to move
>> on:
>>
>> 1. switch imx-ocotp-ele.c to use ELE API exclusively
>>    -> this will create a hard dependency on the ELE firmware/driver 
>> being available
> 
> Could this cause problems for real-time Linux users? Usually going
> through a firmware driver adds more latency than doing the thing
> from Linux directly, and the firmware is usually not preemptable.
> 
> In particular, programming a one-time fuse is likely a slow
> operation in hardware, so it may still be necessary to support
> both methods if there are users that need to update the fuses
> on real-time systems.

Hm, interesting thought. I can't really tell if that could end up being
a real problem, but it might just be another good argument for
supporting both methods, yes.