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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5A1B3C3A5A1 for ; Wed, 28 Aug 2019 16:08:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D21B2077B for ; Wed, 28 Aug 2019 16:08:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726472AbfH1QIJ (ORCPT ); Wed, 28 Aug 2019 12:08:09 -0400 Received: from foss.arm.com ([217.140.110.172]:33724 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726415AbfH1QIJ (ORCPT ); Wed, 28 Aug 2019 12:08:09 -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 9F9CD28; Wed, 28 Aug 2019 09:08:08 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 496C53F59C; Wed, 28 Aug 2019 09:08:07 -0700 (PDT) Date: Wed, 28 Aug 2019 17:08:05 +0100 From: Mark Rutland To: Viresh Kumar Cc: stable@vger.kernel.org, Julien Thierry , linux-arm-kernel@lists.infradead.org, Catalin Marinas , Marc Zyngier , Will Deacon , Russell King , Vincent Guittot , mark.brown@arm.com Subject: Re: [PATCH v4.4 V2 24/43] arm64: Add skeleton to harden the branch predictor against aliasing attacks Message-ID: <20190828160804.GB42408@lakrids.cambridge.arm.com> References: <4349161f0ed572bbc6bff64bad94aa96d07b27ff.1562908075.git.viresh.kumar@linaro.org> <20190731164556.GI39768@lakrids.cambridge.arm.com> <20190801052011.2hrei36v4zntyfn5@vireshk-i7> <20190806121816.GD475@lakrids.cambridge.arm.com> <20190808120600.qhbhopvp4e5w33at@vireshk-i7> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190808120600.qhbhopvp4e5w33at@vireshk-i7> User-Agent: Mutt/1.11.1+11 (2f07cb52) (2018-12-01) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Thu, Aug 08, 2019 at 05:36:00PM +0530, Viresh Kumar wrote: > On 06-08-19, 13:18, Mark Rutland wrote: > > Upstream and in v4.9, the meltdown patches came before the spectre > > patches, and doing this in the opposite order causes context problems > > like the above. > > > > Given that, I think it would be less surprising to do the meltdown > > backport first, though I apprecaite that's more work to get these > > patches in. :/ > > I attempted meltdown backport in the last two days and the amount of > extra patches to be backported is enormous. And I am not sure if > everything is alright as well now, and things will greatly rely on > reviews from you for it. > > For this series, what about just backporting for now to account for > CSV3 ? And attempting meltdown backport separately later ? > > 179a56f6f9fb arm64: Take into account ID_AA64PFR0_EL1.CSV3 I don't think that buys us anything; that's still going to cause some context problems (e.g. for commit 179a56f6f9fb itself), and still means that the v4.4 backport differs from all the others. If it's really not feasible to do the meltdown patches first, then I reluctantly agree that we should just do the spectre bits alone if there aren't major changes that have to be made to entry.S and friends as a result. Could you send a v3 (of just the spectre bits) with the changes requested so far? Thanks, Mark.