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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 94382C5CFE7 for ; Tue, 10 Jul 2018 18:29:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D17E20B6F for ; Tue, 10 Jul 2018 18:29:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5D17E20B6F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org 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 S2387865AbeGJS3u (ORCPT ); Tue, 10 Jul 2018 14:29:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45428 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732245AbeGJS3t (ORCPT ); Tue, 10 Jul 2018 14:29:49 -0400 Received: from localhost (LFbn-1-12247-202.w90-92.abo.wanadoo.fr [90.92.61.202]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 45F11EB4; Tue, 10 Jul 2018 18:29:37 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Lutomirski , Borislav Petkov , Borislav Petkov , Brian Gerst , Dave Hansen , Fenghua Yu , "H. Peter Anvin" , Linus Torvalds , Matthew Whitehead , Oleg Nesterov , One Thousand Gnomes , Peter Zijlstra , Rik van Riel , Thomas Gleixner , Yu-cheng Yu , Ingo Molnar Subject: [PATCH 4.9 18/52] x86/cpu: Re-apply forced caps every time CPU caps are re-read Date: Tue, 10 Jul 2018 20:24:46 +0200 Message-Id: <20180710182451.211448595@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180710182449.285532226@linuxfoundation.org> References: <20180710182449.285532226@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski commit 60d3450167433f2d099ce2869dc52dd9e7dc9b29 upstream. Calling get_cpu_cap() will reset a bunch of CPU features. This will cause the system to lose track of force-set and force-cleared features in the words that are reset until the end of CPU initialization. This can cause X86_FEATURE_FPU, for example, to change back and forth during boot and potentially confuse CPU setup. To minimize the chance of confusion, re-apply forced caps every time get_cpu_cap() is called. Signed-off-by: Andy Lutomirski Reviewed-by: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Fenghua Yu Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Matthew Whitehead Cc: Oleg Nesterov Cc: One Thousand Gnomes Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Yu-cheng Yu Link: http://lkml.kernel.org/r/c817eb373d2c67c2c81413a70fc9b845fa34a37e.1484705016.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/common.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -848,6 +848,13 @@ void get_cpu_cap(struct cpuinfo_x86 *c) init_scattered_cpuid_features(c); init_speculation_control(c); + + /* + * Clear/Set all flags overridden by options, after probe. + * This needs to happen each time we re-probe, which may happen + * several times during CPU initialization. + */ + apply_forced_caps(c); } static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)