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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 0A7B0C64E7A for ; Tue, 1 Dec 2020 16:03:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2C38D22210 for ; Tue, 1 Dec 2020 16:02:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="iJYk51lY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404014AbgLAQC6 (ORCPT ); Tue, 1 Dec 2020 11:02:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388988AbgLAQC5 (ORCPT ); Tue, 1 Dec 2020 11:02:57 -0500 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F526C0613D4; Tue, 1 Dec 2020 08:02:17 -0800 (PST) Received: from zn.tnic (p200300ec2f0e6a009ae7ed3e982f3c10.dip0.t-ipconnect.de [IPv6:2003:ec:2f0e:6a00:9ae7:ed3e:982f:3c10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id CD9341EC04B9; Tue, 1 Dec 2020 17:02:15 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1606838535; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=SxSydwEX7m96SIq00HrPmCp+mPAnCkJ48WYzsRg9t2w=; b=iJYk51lYHndAR22VW5aqtG8DZmC26iF5UFfr3bh2BnR+sTzvvpV653bT3cxXBCWtbz76cL LO93i127VhTlLn0X1nhsOK0o/4EWL74UjiUQZEJ08Ep3dbwkmbm9z1bt+iMe8HwDdUrv3W e1BLblJOCST0k1xlGtguap+j53Mc8TY= Date: Tue, 1 Dec 2020 17:02:12 +0100 From: Borislav Petkov To: "Yu, Yu-cheng" Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang , Pengfei Xu Subject: Re: [PATCH v15 05/26] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack Message-ID: <20201201160212.GF22927@zn.tnic> References: <20201110162211.9207-1-yu-cheng.yu@intel.com> <20201110162211.9207-6-yu-cheng.yu@intel.com> <20201127171012.GD13163@zn.tnic> <98e1b159-bf32-5c67-455b-f798023770ef@intel.com> <20201130181500.GH6019@zn.tnic> <1db3d369-734e-9925-fa14-e799a19ac30c@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1db3d369-734e-9925-fa14-e799a19ac30c@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 30, 2020 at 02:48:09PM -0800, Yu, Yu-cheng wrote: > Logically, enabling IBT without shadow stack does not make sense, but these > features have different CPUIDs, and CONFIG_X86_SHADOW_STACK_USER and > CONFIG_X86_BRANCH_TRACKING_USER can be selected separately. > > Do we want to have only one selection for both features? In other words, we > turn on both or neither. Question is, do they need to be handled separately at all? If not and IOW, I like dhansen's X86_FEATURE_CET synthetic feature suggestion. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette