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 C29FBC433DB for ; Wed, 24 Feb 2021 19:21:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8833B64F06 for ; Wed, 24 Feb 2021 19:21:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235461AbhBXTVh (ORCPT ); Wed, 24 Feb 2021 14:21:37 -0500 Received: from mail.skyhub.de ([5.9.137.197]:38334 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233844AbhBXTV2 (ORCPT ); Wed, 24 Feb 2021 14:21:28 -0500 Received: from zn.tnic (p200300ec2f0d180087c1c74682a645c2.dip0.t-ipconnect.de [IPv6:2003:ec:2f0d:1800:87c1:c746:82a6:45c2]) (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 507A51EC059E; Wed, 24 Feb 2021 20:20:45 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1614194445; 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=3KL8YvjOAtjWZ0z5XApK+XEOauVtwVi+B47aqtn8H6I=; b=mU+6+QiGhPI3QgSfJO8WtdDUQZczU4O1+XkxsiCcohvgO2ZUPgfOPNq+vKM7H/RVGw7+lC Xd0Wn/6HNCoNle0dTSziAJ5HGWBmhtk9M0qDr8E75eRDkB1kzvwBRgKsHJLnNpU/0VWxt0 j1KQhgTDMPpwZUm1maEaStjwTKf/gPU= Date: Wed, 24 Feb 2021 20:20:44 +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 , Haitao Huang , Michael Kerrisk Subject: Re: [PATCH v21 06/26] x86/cet: Add control-protection fault handler Message-ID: <20210224192044.GH20344@zn.tnic> References: <20210217222730.15819-1-yu-cheng.yu@intel.com> <20210217222730.15819-7-yu-cheng.yu@intel.com> <20210224161343.GE20344@zn.tnic> <32ac05ef-b50b-c947-095d-bc31a42947a3@intel.com> <20210224165332.GF20344@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 24, 2021 at 09:56:13AM -0800, Yu, Yu-cheng wrote: > No. Maybe I am doing too much. The GP fault sets si_addr to zero, for > example. So maybe do the same here? No, you're looking at this from the wrong angle. This is going to be user-visible and the moment it gets upstream, it is cast in stone. So the whole use case of what luserspace needs to do or is going to do or wants to do on a SEGV_CPERR, needs to be described, agreed upon by people etc before it goes out. And thus clarified whether the address gets copied out or not. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette