From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFAC6C433ED for ; Wed, 19 May 2021 11:23:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FBFB611BF for ; Wed, 19 May 2021 11:23:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350446AbhESLZC (ORCPT ); Wed, 19 May 2021 07:25:02 -0400 Received: from foss.arm.com ([217.140.110.172]:60902 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350438AbhESLYv (ORCPT ); Wed, 19 May 2021 07:24:51 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 4BFB4101E; Wed, 19 May 2021 04:23:30 -0700 (PDT) Received: from bogus (unknown [10.57.72.88]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5A0133F719; Wed, 19 May 2021 04:23:28 -0700 (PDT) Date: Wed, 19 May 2021 12:23:18 +0100 From: Sudeep Holla To: Rob Herring , Viresh Kumar Cc: "linux-kernel@vger.kernel.org" , devicetree@vger.kernel.org, Sudeep Holla , Manivannan Sadhasivam , Hector Yuan , Viresh Kumar , Bjorn Andersson Subject: Re: [PATCH v4] dt-bindings: dvfs: Add support for generic performance domains Message-ID: <20210519112308.umxriuv75onuwvmc@bogus> References: <20210517155458.1016707-1-sudeep.holla@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 17, 2021 at 02:17:05PM -0500, Rob Herring wrote: > On Mon, May 17, 2021 at 10:55 AM Sudeep Holla wrote: > > > > The CLKSCREW attack [0] exposed security vulnerabilities in energy management > > implementations where untrusted software had direct access to clock and > > voltage hardware controls. In this attack, the malicious software was able to > > place the platform into unsafe overclocked or undervolted configurations. Such > > configurations then enabled the injection of predictable faults to reveal > > secrets. > > > > Many Arm-based systems used to or still use voltage regulator and clock > > frameworks in the kernel. These frameworks allow callers to independently > > manipulate frequency and voltage settings. Such implementations can render > > systems susceptible to this form of attack. > > > > Attacks such as CLKSCREW are now being mitigated by not having direct and > > independent control of clock and voltage in the kernel and moving that > > control to a trusted entity, such as the SCP firmware or secure world > > firmware/software which are to perform sanity checking on the requested > > performance levels, thereby preventing any attempted malicious programming. > > > > With the advent of such an abstraction, there is a need to replace the > > generic clock and regulator bindings used by such devices with a generic > > performance domains bindings. > > > > [0] https://www.usenix.org/conference/usenixsecurity17/technical-sessions/presentation/tang > > > > Link: https://lore.kernel.org/r/20201116181356.804590-1-sudeep.holla@arm.com > > Cc: Rob Herring > > Acked-by: Viresh Kumar > > Signed-off-by: Sudeep Holla > > Reviewed-by: Rob Herring Thanks Rob. Viresh, I noticed I haven't cc-ed linux-pm list, do you need me to post there or are you happy to pick it up from here when Hector's mediatek cpufreq drivers using this are ready to be merged ? -- Regards, Sudeep