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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 A1EA3C606BD for ; Mon, 8 Jul 2019 15:49:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6D5CB216F4 for ; Mon, 8 Jul 2019 15:49:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562600974; bh=FLoJA22TisOPhVmd/CYDRTtX172G09Aaw02XtNAeIJE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=EI9gw0oyTnzzHpoxr//f08S1XN6VRPUM/KZschYyPf3RN63p/gekGJWnpRFh4fq6q miEaV7CV0jNEiDvaZFNOSDGtMXpcfH+EBfcBgHaHtHjZOSUNBHjEk0l2EIvPg7HJbE GLZkaws7YvXmWgs0rQuqUPYB4ayUisM+ScmbfcMI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732568AbfGHPQa (ORCPT ); Mon, 8 Jul 2019 11:16:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:39296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732526AbfGHPQW (ORCPT ); Mon, 8 Jul 2019 11:16:22 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BF010216E3; Mon, 8 Jul 2019 15:16:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1562598981; bh=FLoJA22TisOPhVmd/CYDRTtX172G09Aaw02XtNAeIJE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XkDo1/ng70LDOcv5JHE6QDVGuxPfdwsvnY0wMz6bLq2Mmwx+pwzZ9Ec/JRojLSQuF PN3BZRT7A8BKuO3ONO9UIx5ea9SEwBdpEZ+Q1vNMnsNoGokjdtzmUyEtAfrSrt6scH MErq7i3LSQS7739Z+dJEh7e4+DpAJ9UkIbclWPy0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Geert Uytterhoeven , Thomas Gleixner , Josh Poimboeuf , Peter Zijlstra , Jiri Kosina , Ben Hutchings Subject: [PATCH 4.4 39/73] cpu/speculation: Warn on unsupported mitigations= parameter Date: Mon, 8 Jul 2019 17:12:49 +0200 Message-Id: <20190708150523.406204248@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190708150513.136580595@linuxfoundation.org> References: <20190708150513.136580595@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Geert Uytterhoeven commit 1bf72720281770162c87990697eae1ba2f1d917a upstream. Currently, if the user specifies an unsupported mitigation strategy on the kernel command line, it will be ignored silently. The code will fall back to the default strategy, possibly leaving the system more vulnerable than expected. This may happen due to e.g. a simple typo, or, for a stable kernel release, because not all mitigation strategies have been backported. Inform the user by printing a message. Fixes: 98af8452945c5565 ("cpu/speculation: Add 'mitigations=' cmdline option") Signed-off-by: Geert Uytterhoeven Signed-off-by: Thomas Gleixner Acked-by: Josh Poimboeuf Cc: Peter Zijlstra Cc: Jiri Kosina Cc: Greg Kroah-Hartman Cc: Ben Hutchings Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190516070935.22546-1-geert@linux-m68k.org Signed-off-by: Greg Kroah-Hartman --- kernel/cpu.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -851,6 +851,9 @@ static int __init mitigations_parse_cmdl cpu_mitigations = CPU_MITIGATIONS_OFF; else if (!strcmp(arg, "auto")) cpu_mitigations = CPU_MITIGATIONS_AUTO; + else + pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", + arg); return 0; }