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=-2.1 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 2C5B1ECDE5F for ; Thu, 19 Jul 2018 11:16:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BA83220684 for ; Thu, 19 Jul 2018 11:16:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="ML7taaXY" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BA83220684 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731050AbeGSL7a (ORCPT ); Thu, 19 Jul 2018 07:59:30 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:55418 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726956AbeGSL7a (ORCPT ); Thu, 19 Jul 2018 07:59:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2014; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=N55mkapZHY83Xr05UeAZUp1286KZ1rYWGL8uKx4AojQ=; b=ML7taaXYJ7afiptwY+jf5gUYq 6aCTllnOmxGwff6pH0pbWWCfRl8bNOrWvg5gYTdIZFlXvkqX5aE+T2RAoHhUBhOpMOfAeQiu0mnKz /9IwTxWGe8vXZCrR5PgpCRcgQNFtB7QP0DJpo51LUN29DkNoNXmuCX86TmNU67+CzqRm0=; Received: from n2100.armlinux.org.uk ([fd8f:7570:feb6:1:214:fdff:fe10:4f86]:55921) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.90_1) (envelope-from ) id 1fg6vN-0005J6-Ph; Thu, 19 Jul 2018 12:16:45 +0100 Received: from linux by n2100.armlinux.org.uk with local (Exim 4.90_1) (envelope-from ) id 1fg6vK-0001nb-OD; Thu, 19 Jul 2018 12:16:42 +0100 Date: Thu, 19 Jul 2018 12:16:41 +0100 From: Russell King - ARM Linux To: Morten Rasmussen Cc: Dietmar Eggemann , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Qais Yousef Subject: Re: arm: v4.18-rc5 with cpuidle on TC2 (A7 boot) spectre v2 issue Message-ID: <20180719111640.GJ17271@n2100.armlinux.org.uk> References: <2abc6c11-2e8c-a4ea-6911-0f495d90ace6@arm.com> <20180719100109.GH17271@n2100.armlinux.org.uk> <20180719103919.GB19287@e105550-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180719103919.GB19287@e105550-lin.cambridge.arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 19, 2018 at 11:39:19AM +0100, Morten Rasmussen wrote: > On Thu, Jul 19, 2018 at 11:01:10AM +0100, Russell King - ARM Linux wrote: > > On Thu, Jul 19, 2018 at 11:42:50AM +0200, Dietmar Eggemann wrote: > > > Hi, > > > > > > running v4.18-rc5 (plus still missing "power: vexpress: fix corruption in > > > notifier registration", otherwise I get this rcu_sched stall issue) on TC2 > > > (A7 boot) with vanilla multi_v7_defconfig plus > > > CONFIG_ARM_BIG_LITTLE_CPUIDLE=y gives me continuous: > > > > > > ... > > > CPUX: Spectre v2: incorrect context switching function, system vulnerable > > > ... > > > > > > messages. > > > > > > Work around is to disable CONFIG_HARDEN_BRANCH_PREDICTOR. > > > > or disable big.Little if you want the hardening. > > > > The choices are currently either protection against Spectre or big.Little > > support since the two are mutually exclusive at the moment. > > Would it be possible to make those message only appear once like they do > when booting on A15? Yes, it's possible. Feel free to send a patch, thanks. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps up According to speedtest.net: 13Mbps down 490kbps up