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=-11.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 7F22CC433E0 for ; Wed, 10 Feb 2021 19:36:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46D5264DAE for ; Wed, 10 Feb 2021 19:36:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232560AbhBJTgS (ORCPT ); Wed, 10 Feb 2021 14:36:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232854AbhBJTfS (ORCPT ); Wed, 10 Feb 2021 14:35:18 -0500 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4511EC06174A for ; Wed, 10 Feb 2021 11:35:03 -0800 (PST) Received: by mail-pf1-x42b.google.com with SMTP id d26so1947922pfn.5 for ; Wed, 10 Feb 2021 11:35:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=lVugRE6fF0oJTBQd7d0RHKP3QOjg3imenXxdGjYCNio=; b=FOurCcBoEOTC173g8WpQOh8MpvMQlo/WlTwQI/cXieTsGgI0OsJU6jFdMuPewnsA8x N+Lu45EOVe6MZGpC4MeQO9562gudu7ifC8x9TKKAd7WGRrJKzSki8Id6v4RZ3j9MW3T3 T3kC9Rjk7f1qpSc/LzUtjVX0oVYUJoOrnsQ4k= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=lVugRE6fF0oJTBQd7d0RHKP3QOjg3imenXxdGjYCNio=; b=DNTCcOAF5TjVZmjF/HSuSiJ3V/7JZpehmafmPa0szQikgItzYyMnKsbF3d00nEu8Kp aCa1FQ4oGRJYKcH0SrdW6Ea7jwuKhg2Dia8WmCiTcvK6pYcFioL86zK321yaVo5iiY6A GB1OMef8dmwYQWt8WTduPAD+jOS9sDPgauWIcVENTpeFk5RAkSay4EIIhSJkeOngkEBH 4bYYIWVw04dzBb1hr+SkHPhQnpxhg4irkQT41eqqlpU7zMfyfoWrd3SPqGvvHRxeqnS2 Spq90UV4XTPYDygr1U365QmA0Wg/vvbKqJr0Hx6fWGlZon7nxsltel4q2DFe7rJKmc04 UHdA== X-Gm-Message-State: AOAM530c9IRVWI7xgpMMmvJI2UIMJ+9H6FW0RwFB1RNF02vfLlEaK9fj MjkjB4Y57ZYgoyxJFn2zY5a4WQ== X-Google-Smtp-Source: ABdhPJyw/brekoVah28J4DYypOu+xfbWlmLb9xtdz4+0cBteusjYuV6Y5OvqRl1eOPZCqvkxSdOONQ== X-Received: by 2002:a62:8445:0:b029:1c1:c862:8fc4 with SMTP id k66-20020a6284450000b02901c1c8628fc4mr4506463pfd.77.1612985702870; Wed, 10 Feb 2021 11:35:02 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id u127sm3234989pfb.180.2021.02.10.11.35.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Feb 2021 11:35:02 -0800 (PST) Date: Wed, 10 Feb 2021 11:35:01 -0800 From: Kees Cook To: Yu-cheng Yu 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 , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , 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@intel.com, Christoph Hellwig Subject: Re: [PATCH v20 07/25] x86/mm: Remove _PAGE_DIRTY from kernel RO pages Message-ID: <202102101134.72F7495@keescook> References: <20210210175703.12492-1-yu-cheng.yu@intel.com> <20210210175703.12492-8-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210210175703.12492-8-yu-cheng.yu@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Wed, Feb 10, 2021 at 09:56:45AM -0800, Yu-cheng Yu wrote: > The x86 family of processors do not directly create read-only and Dirty > PTEs. These PTEs are created by software. One such case is that kernel > read-only pages are historically setup as Dirty. > > New processors that support Shadow Stack regard read-only and Dirty PTEs as > shadow stack pages. This results in ambiguity between shadow stack and > kernel read-only pages. To resolve this, removed Dirty from kernel read- > only pages. > > Signed-off-by: Yu-cheng Yu Reviewed-by: Kees Cook -- Kees Cook