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 D57CCC432BE for ; Fri, 27 Aug 2021 18:20:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5F11960FE6 for ; Fri, 27 Aug 2021 18:20:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5F11960FE6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 8CFBE6B006C; Fri, 27 Aug 2021 14:20:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 87E9D8D0001; Fri, 27 Aug 2021 14:20:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 76CE96B0074; Fri, 27 Aug 2021 14:20:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0129.hostedemail.com [216.40.44.129]) by kanga.kvack.org (Postfix) with ESMTP id 5BEEE6B006C for ; Fri, 27 Aug 2021 14:20:26 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id E6A5D1835B733 for ; Fri, 27 Aug 2021 18:20:25 +0000 (UTC) X-FDA: 78521675610.08.1273B1D Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by imf30.hostedemail.com (Postfix) with ESMTP id 930B8E0016BB for ; Fri, 27 Aug 2021 18:20:25 +0000 (UTC) Received: from zn.tnic (p200300ec2f111700cf40790d4c46ba75.dip0.t-ipconnect.de [IPv6:2003:ec:2f11:1700:cf40:790d:4c46:ba75]) (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 580311EC0464; Fri, 27 Aug 2021 20:20:20 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1630088420; 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=ZX+dUaso9hY7Jwyhm9+J+9xSIFkf/Ba913Jr6PxHR8M=; b=hxhN/9qaxv9CejLRWw/PIxqlAS/tScL1xrIYrKtj0tITUY//ZNg6TZHq5y6GLCwkNmGnkE ea7gb0qDI/2HlzvGLbqA8//rLOTvTBv+aGCGxfMwcbe6UrZnn/Srne1S5PpjyNBIjZoDrV Ii6Bm3VbSHJ/Qikkp8eaLIl1EwOJ1So= Date: Fri, 27 Aug 2021 20:21:02 +0200 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" , Dave Martin , Weijiang Yang , Pengfei Xu , Haitao Huang , Rick P Edgecombe Subject: Re: [PATCH v29 23/32] x86/cet/shstk: Add user-mode shadow stack support Message-ID: References: <20210820181201.31490-1-yu-cheng.yu@intel.com> <20210820181201.31490-24-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=alien8.de header.s=dkim header.b="hxhN/9qa"; dmarc=pass (policy=none) header.from=alien8.de; spf=pass (imf30.hostedemail.com: domain of bp@alien8.de designates 5.9.137.197 as permitted sender) smtp.mailfrom=bp@alien8.de X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 930B8E0016BB X-Stat-Signature: ka7eramtpxbsz7468peojszcsnxqpen4 X-HE-Tag: 1630088425-724125 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 Fri, Aug 27, 2021 at 11:10:31AM -0700, Yu, Yu-cheng wrote: > Because on context switches the whole xstates are switched together, > we need to make sure all are in registers. There's context switch code which does that already. Why would shstk_setup() be responsible for switching the whole extended states buffer instead of only the shadow stack stuff only? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette