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=-6.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 833DAC65BAE for ; Thu, 13 Dec 2018 11:09:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E8EE20849 for ; Thu, 13 Dec 2018 11:09:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E8EE20849 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com 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 S1728610AbeLMLJa (ORCPT ); Thu, 13 Dec 2018 06:09:30 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:59314 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726178AbeLMLJ3 (ORCPT ); Thu, 13 Dec 2018 06:09:29 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 23A8CA78; Thu, 13 Dec 2018 03:09:29 -0800 (PST) Received: from [10.1.197.36] (e112298-lin.cambridge.arm.com [10.1.197.36]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 544B23F59C; Thu, 13 Dec 2018 03:09:27 -0800 (PST) Subject: Re: [PATCH 4/6] arm64: add sysfs vulnerability show for spectre v2 To: Jeremy Linton , linux-arm-kernel@lists.infradead.org Cc: catalin.marinas@arm.com, will.deacon@arm.com, marc.zyngier@arm.com, suzuki.poulose@arm.com, dave.martin@arm.com, shankerd@codeaurora.org, mark.rutland@arm.com, linux-kernel@vger.kernel.org, ykaukab@suse.de References: <20181206234408.1287689-1-jeremy.linton@arm.com> <20181206234408.1287689-5-jeremy.linton@arm.com> From: Julien Thierry Message-ID: <6c572de0-da38-c273-82ed-bafb86bbfa7a@arm.com> Date: Thu, 13 Dec 2018 11:09:25 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181206234408.1287689-5-jeremy.linton@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/12/2018 23:44, Jeremy Linton wrote: > Add code to track whether all the cores in the machine are > vulnerable, and whether all the vulnerable cores have been > mitigated. > > Once we have that information we can add the sysfs stub and > provide an accurate view of what is known about the machine. > > Signed-off-by: Jeremy Linton > --- > arch/arm64/kernel/cpu_errata.c | 72 +++++++++++++++++++++++++++++++--- > 1 file changed, 67 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c > index 559ecdee6fd2..6505c93d507e 100644 > --- a/arch/arm64/kernel/cpu_errata.c > +++ b/arch/arm64/kernel/cpu_errata.c [...] > @@ -766,4 +812,20 @@ ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, > return sprintf(buf, "Mitigation: __user pointer sanitization\n"); > } > > +ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, > + char *buf) > +{ > + switch (__spectrev2_safe) { > + case A64_SV2_SAFE: > + return sprintf(buf, "Not affected\n"); > + case A64_SV2_UNSAFE: > + if (__hardenbp_enab == A64_HBP_MIT) > + return sprintf(buf, > + "Mitigation: Branch predictor hardening\n"); > + return sprintf(buf, "Vulnerable\n"); > + default: > + return sprintf(buf, "Unknown\n"); > + } Again I see that we are going to display "Unknown" when the mitigation is not built in. Couldn't we make that CONFIG_GENERIC_CPU_VULNERABILITIES check whether a CPU is vulnerable or not even if the mitigation is not implemented? It's just checking the list of MIDRs. Thanks, -- Julien Thierry