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=-8.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 DBE35C2D0A3 for ; Tue, 3 Nov 2020 17:53:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F0DD22280 for ; Tue, 3 Nov 2020 17:53:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727857AbgKCRxi (ORCPT ); Tue, 3 Nov 2020 12:53:38 -0500 Received: from mga02.intel.com ([134.134.136.20]:52396 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727706AbgKCRxh (ORCPT ); Tue, 3 Nov 2020 12:53:37 -0500 IronPort-SDR: +SOzUzL1fDlFqmr9jBEiJiQLV1mkD99kYQ2eOYtc/hvHhowIcZz4HmcA03XEnLD/xqUOWHURUV wzn5Fhbt8qRw== X-IronPort-AV: E=McAfee;i="6000,8403,9794"; a="156085221" X-IronPort-AV: E=Sophos;i="5.77,448,1596524400"; d="scan'208";a="156085221" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Nov 2020 09:53:36 -0800 IronPort-SDR: t3rM9zLgd6ZRLLAjOl3vZJlufQNSBy4tjSshCJtsEFelCEQ7FWt2oAwJFA325Js+8uCWdVnDR2 O0TkS4PUyBAA== X-IronPort-AV: E=Sophos;i="5.77,448,1596524400"; d="scan'208";a="538578108" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Nov 2020 09:53:36 -0800 Date: Tue, 3 Nov 2020 09:53:36 -0800 From: Ira Weiny To: Greg KH Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra , Dave Hansen , Fenghua Yu , x86@kernel.org, Dan Williams , Andrew Morton , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH V2 05/10] x86/pks: Add PKS kernel API Message-ID: <20201103175335.GA1531489@iweiny-DESK2.sc.intel.com> References: <20201102205320.1458656-1-ira.weiny@intel.com> <20201102205320.1458656-6-ira.weiny@intel.com> <20201103065024.GC75930@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201103065024.GC75930@kroah.com> User-Agent: Mutt/1.11.1 (2018-12-01) Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On Tue, Nov 03, 2020 at 07:50:24AM +0100, Greg KH wrote: > On Mon, Nov 02, 2020 at 12:53:15PM -0800, ira.weiny@intel.com wrote: > > From: Fenghua Yu > > [snip] > > diff --git a/include/linux/pkeys.h b/include/linux/pkeys.h > > index 2955ba976048..0959a4c0ca64 100644 > > --- a/include/linux/pkeys.h > > +++ b/include/linux/pkeys.h > > @@ -50,4 +50,28 @@ static inline void copy_init_pkru_to_fpregs(void) > > > > #endif /* ! CONFIG_ARCH_HAS_PKEYS */ > > > > +#define PKS_FLAG_EXCLUSIVE 0x00 > > + > > +#ifndef CONFIG_ARCH_HAS_SUPERVISOR_PKEYS > > +static inline int pks_key_alloc(const char * const pkey_user, int flags) > > +{ > > + return -EOPNOTSUPP; > > +} > > +static inline void pks_key_free(int pkey) > > +{ > > +} > > +static inline void pks_mk_noaccess(int pkey) > > +{ > > + WARN_ON_ONCE(1); > > So for panic-on-warn systems, this is ok to reboot the box? I would not expect this to reboot the box no. But it is a violation of the API contract. If pky_key_alloc() returns an error calling any of the other functions is an error. > > Are you sure, that feels odd... It does feel odd and downright wrong... But there are a lot of WARN_ON_ONCE's out there to catch this type of internal programming error. Is panic-on-warn commonly used? Ira