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, 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 B62CAC468C6 for ; Thu, 19 Jul 2018 10:01:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 278F2206B7 for ; Thu, 19 Jul 2018 10:01:25 +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="GJ82OvY6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 278F2206B7 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 S1727553AbeGSKnp (ORCPT ); Thu, 19 Jul 2018 06:43:45 -0400 Received: from pandora.armlinux.org.uk ([78.32.30.218]:54402 "EHLO pandora.armlinux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727146AbeGSKnp (ORCPT ); Thu, 19 Jul 2018 06:43:45 -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=QUG90RfdbvUh/JohGyvpw3u01oT9TZtGCKW95LYmh3U=; b=GJ82OvY6tTfDvon/RZX0r5V5A m1KQXTFwdae94C215oJ9gY9OVKfZGYZbJxINwBkx7+I+SllgH1t2X6YUWmXA7uA7NjWYdvVgXC36V l/8rLnuB8cPUi1gh5iBfLw1SZmYX145yaGAgFExUR24a67HEtftfnXQf/RpHvneV7ZWSE=; Received: from n2100.armlinux.org.uk ([2002:4e20:1eda:1:214:fdff:fe10:4f86]:60047) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.90_1) (envelope-from ) id 1fg5kM-0004xq-Om; Thu, 19 Jul 2018 11:01:18 +0100 Received: from linux by n2100.armlinux.org.uk with local (Exim 4.90_1) (envelope-from ) id 1fg5kH-0000lS-V3; Thu, 19 Jul 2018 11:01:14 +0100 Date: Thu, 19 Jul 2018 11:01:10 +0100 From: Russell King - ARM Linux To: Dietmar Eggemann Cc: linux-arm-kernel@lists.infradead.org, Morten Rasmussen , Qais Yousef , linux-kernel@vger.kernel.org Subject: Re: arm: v4.18-rc5 with cpuidle on TC2 (A7 boot) spectre v2 issue Message-ID: <20180719100109.GH17271@n2100.armlinux.org.uk> References: <2abc6c11-2e8c-a4ea-6911-0f495d90ace6@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2abc6c11-2e8c-a4ea-6911-0f495d90ace6@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 11:42:50AM +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. -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@armlinux.org.uk (Russell King - ARM Linux) Date: Thu, 19 Jul 2018 11:01:10 +0100 Subject: arm: v4.18-rc5 with cpuidle on TC2 (A7 boot) spectre v2 issue In-Reply-To: <2abc6c11-2e8c-a4ea-6911-0f495d90ace6@arm.com> References: <2abc6c11-2e8c-a4ea-6911-0f495d90ace6@arm.com> Message-ID: <20180719100109.GH17271@n2100.armlinux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. -- 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