linux-kernel - Re: [PATCH] regmap: prevent noinc writes from clobbering cache

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: <72d79cd8-9054-4e98-8e44-808aca952221@sirena.org.uk>
Date:   Wed, 1 Nov 2023 20:24:45 +0000
From:   Mark Brown <broonie@...nel.org>
To:     Ben Wolsieffer <ben.wolsieffer@...ring.com>
Cc:     linux-kernel@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Ben Whitten <ben.whitten@...il.com>
Subject: Re: [PATCH] regmap: prevent noinc writes from clobbering cache

On Wed, Nov 01, 2023 at 04:20:08PM -0400, Ben Wolsieffer wrote:
> On Wed, Nov 01, 2023 at 05:05:39PM +0000, Mark Brown wrote:

> > Could you please add a kunit test for this?

> I started to look into this, but it is not currently possible to test
> noinc behavior with regmap_[raw_]ram. The same bulk write operation is
> used by both incrementing and non-incrementing writes, and the difference
> in behavior is due to how the hardware handles the bulk write to a
> particular register.

> To test this behavior, regmap_raw_ram (raw because it supports bulk
> writes) would have to be told that certain of its registers should
> implement noinc semantics.

> Is this something I should implement?

That would be great, yes - I've just been implementing features in those
map types on an as needed basis as I've been writing tests and I didn't
get round to covering noinc yet.

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)