From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 7AB2C7DF8A for ; Thu, 7 Jun 2018 16:02:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933239AbeFGQCX (ORCPT ); Thu, 7 Jun 2018 12:02:23 -0400 Received: from mga18.intel.com ([134.134.136.126]:15647 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932903AbeFGQCI (ORCPT ); Thu, 7 Jun 2018 12:02:08 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Jun 2018 09:02:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,486,1520924400"; d="scan'208";a="235254820" Received: from 2b52.sc.intel.com (HELO [143.183.136.51]) ([143.183.136.51]) by fmsmga005.fm.intel.com with ESMTP; 07 Jun 2018 09:02:07 -0700 Message-ID: <1528387137.4636.6.camel@2b52.sc.intel.com> Subject: Re: [PATCH 2/9] x86/cet: Add Kconfig option for user-mode shadow stack From: Yu-cheng Yu To: Andy Lutomirski Cc: LKML , linux-doc@vger.kernel.org, Linux-MM , linux-arch , X86 ML , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , "H. J. Lu" , "Shanbhogue, Vedvyas" , "Ravi V. Shankar" , Dave Hansen , Jonathan Corbet , Oleg Nesterov , Arnd Bergmann , mike.kravetz@oracle.com Date: Thu, 07 Jun 2018 08:58:57 -0700 In-Reply-To: References: <20180607143705.3531-1-yu-cheng.yu@intel.com> <20180607143705.3531-3-yu-cheng.yu@intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Thu, 2018-06-07 at 08:47 -0700, Andy Lutomirski wrote: > On Thu, Jun 7, 2018 at 7:40 AM Yu-cheng Yu wrote: > > > > Introduce Kconfig option X86_INTEL_SHADOW_STACK_USER. > > > > An application has shadow stack protection when all the following are > > true: > > > > (1) The kernel has X86_INTEL_SHADOW_STACK_USER enabled, > > (2) The running processor supports the shadow stack, > > (3) The application is built with shadow stack enabled tools & libs > > and, and at runtime, all dependent shared libs can support shadow > > stack. > > > > If this kernel config option is enabled, but (2) or (3) above is not > > true, the application runs without the shadow stack protection. > > Existing legacy applications will continue to work without the shadow > > stack protection. > > > > The user-mode shadow stack protection is only implemented for the > > 64-bit kernel. Thirty-two bit applications are supported under the > > compatibility mode. > > > > The 64-bit only part seems entirely reasonable. So please make the > code 64-bit only :) Yes, I will remove changes in "arch/x86/entry/entry32.S". We still want to support x32/ia32 in the 64-bit kernel, right? -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html