From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754927AbbCBX7f (ORCPT ); Mon, 2 Mar 2015 18:59:35 -0500 Received: from mga03.intel.com ([134.134.136.65]:37293 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754002AbbCBX7e (ORCPT ); Mon, 2 Mar 2015 18:59:34 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,678,1418112000"; d="scan'208";a="659485161" Message-ID: <54F4F964.5030701@intel.com> Date: Mon, 02 Mar 2015 15:59:32 -0800 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: LKML , the arch/x86 maintainers , "Yu, Fenghua" Subject: xsaves support broken? Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Fenghua, I was testing some new MPX code, and realized that MPX had stopped working completely. The prctl() failed to turn it on, which I tracked down to a 0 in "BNDCSR" where we expected to see an enable bit. I realized that I had managed to remove the "noxsaves" boot option from my kernel. Re-adding "noxsaves" made MPX work again, and the BNDCSR contents were properly passed in to the kernel. Is it possible that "xsaves" use inside the kernel is simply broken? Config is here: http://sr71.net/~dave/intel/config-20150302