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 46204C433E0 for ; Wed, 24 Feb 2021 19:20:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id ABDA564EBA for ; Wed, 24 Feb 2021 19:20:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ABDA564EBA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1F93F6B0005; Wed, 24 Feb 2021 14:20:50 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1A8046B0006; Wed, 24 Feb 2021 14:20:50 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0BE5F6B006C; Wed, 24 Feb 2021 14:20:50 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0244.hostedemail.com [216.40.44.244]) by kanga.kvack.org (Postfix) with ESMTP id EB95F6B0005 for ; Wed, 24 Feb 2021 14:20:49 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id B11C2180943C5 for ; Wed, 24 Feb 2021 19:20:49 +0000 (UTC) X-FDA: 77854128618.29.A72B58D Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by imf14.hostedemail.com (Postfix) with ESMTP id 94C38C0007CF for ; Wed, 24 Feb 2021 19:20:41 +0000 (UTC) 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: X-Stat-Signature: b7qwq31u895wcnbum6us7uzrunqoe36i X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 94C38C0007CF Received-SPF: none (alien8.de>: No applicable sender policy available) receiver=imf14; identity=mailfrom; envelope-from=""; helo=mail.skyhub.de; client-ip=5.9.137.197 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614194441-215430 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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