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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 CE4A7C5518C for ; Thu, 23 Apr 2020 01:41:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF56E2074F for ; Thu, 23 Apr 2020 01:41:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726364AbgDWBli (ORCPT ); Wed, 22 Apr 2020 21:41:38 -0400 Received: from mga14.intel.com ([192.55.52.115]:59945 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725828AbgDWBli (ORCPT ); Wed, 22 Apr 2020 21:41:38 -0400 IronPort-SDR: sQ9WEnTgJFmZ4m2fFR7xOKLQ13E9KDDiscG0eAMZvq73Yr+Rvr18iyLRbcOEfDQIlkkZxvYw3K oFvZqVNH3yUg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2020 18:41:37 -0700 IronPort-SDR: CD2YxbVKG2TZwAYql6zhg9T7ino1fY1Mi5HuKZB8EH+PrVBtjVFDYNpQVW0QQZLAhDq21NCJ8o YIB60eV6aoAA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,305,1583222400"; d="scan'208";a="365856621" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.21]) by fmsmga001.fm.intel.com with ESMTP; 22 Apr 2020 18:41:37 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 53EBF3019B5; Wed, 22 Apr 2020 18:41:37 -0700 (PDT) Date: Wed, 22 Apr 2020 18:41:37 -0700 From: Andi Kleen To: John Haxby Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Jonathan Corbet , x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 1/1] x86/fpu: Allow clearcpuid= to clear several bits Message-ID: <20200423014137.GM608746@tassilo.jf.intel.com> References: <03a3a4d135b17115db9ad91413e21af73e244500.1587555769.git.john.haxby@oracle.com> <20200422143554.GI608746@tassilo.jf.intel.com> <96EA2DF4-7490-4FF0-BB3E-EC9157517918@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <96EA2DF4-7490-4FF0-BB3E-EC9157517918@oracle.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > I did wonder about that. However, cmdline_find_option() is specifically documented as > > * Find a non-boolean option (i.e. option=argument). In accordance with > * standard Linux practice, if this option is repeated, this returns the > * last instance on the command line. Okay so would need a special version that uses the first and an option to pass the cmdline string. > > And since that appeared in 2017 I decided to stick with the new-fangled interface :) This is a little-used feature; I'm not sure it's worth the effort of parsing the command line for the old style. What do you think? I'm not sure it's that little used. We use it quite a bit for testing and workarounds, and it might be that some of those are deployed. -Andi