From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755361AbaKPLPu (ORCPT ); Sun, 16 Nov 2014 06:15:50 -0500 Received: from terminus.zytor.com ([198.137.202.10]:35022 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755268AbaKPLPt (ORCPT ); Sun, 16 Nov 2014 06:15:49 -0500 Date: Sun, 16 Nov 2014 03:15:32 -0800 From: tip-bot for Dave Hansen Message-ID: Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, dave.hansen@linux.intel.com, mingo@kernel.org, fenghua.yu@intel.com, dave@sr71.net, hpa@zytor.com Reply-To: dave.hansen@linux.intel.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, hpa@zytor.com, dave@sr71.net, fenghua.yu@intel.com, mingo@kernel.org In-Reply-To: <20141111220133.FE053984@viggo.jf.intel.com> References: <20141111220133.FE053984@viggo.jf.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86: Require exact match for 'noxsave' command line option Git-Commit-ID: 2cd3949f702692cf4c5d05b463f19cd706a92dd3 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 2cd3949f702692cf4c5d05b463f19cd706a92dd3 Gitweb: http://git.kernel.org/tip/2cd3949f702692cf4c5d05b463f19cd706a92dd3 Author: Dave Hansen AuthorDate: Tue, 11 Nov 2014 14:01:33 -0800 Committer: Thomas Gleixner CommitDate: Sun, 16 Nov 2014 12:13:16 +0100 x86: Require exact match for 'noxsave' command line option We have some very similarly named command-line options: arch/x86/kernel/cpu/common.c:__setup("noxsave", x86_xsave_setup); arch/x86/kernel/cpu/common.c:__setup("noxsaveopt", x86_xsaveopt_setup); arch/x86/kernel/cpu/common.c:__setup("noxsaves", x86_xsaves_setup); __setup() is designed to match options that take arguments, like "foo=bar" where you would have: __setup("foo", x86_foo_func...); The problem is that "noxsave" actually _matches_ "noxsaves" in the same way that "foo" matches "foo=bar". If you boot an old kernel that does not know about "noxsaves" with "noxsaves" on the command line, it will interpret the argument as "noxsave", which is not what you want at all. This makes the "noxsave" handler only return success when it finds an *exact* match. [ tglx: We really need to make __setup() more robust. ] Signed-off-by: Dave Hansen Cc: Dave Hansen Cc: Fenghua Yu Cc: x86@kernel.org Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20141111220133.FE053984@viggo.jf.intel.com Signed-off-by: Thomas Gleixner --- arch/x86/kernel/cpu/common.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 4b4f78c..cfa9b5b 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -146,6 +146,8 @@ EXPORT_PER_CPU_SYMBOL_GPL(gdt_page); static int __init x86_xsave_setup(char *s) { + if (strlen(s)) + return 0; setup_clear_cpu_cap(X86_FEATURE_XSAVE); setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT); setup_clear_cpu_cap(X86_FEATURE_XSAVES);