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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ABE31C4321E for ; Sat, 3 Dec 2022 02:34:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235171AbiLCCea (ORCPT ); Fri, 2 Dec 2022 21:34:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51902 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235211AbiLCCe0 (ORCPT ); Fri, 2 Dec 2022 21:34:26 -0500 Received: from mail-pg1-x531.google.com (mail-pg1-x531.google.com [IPv6:2607:f8b0:4864:20::531]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC5D5F9E2E for ; Fri, 2 Dec 2022 18:34:22 -0800 (PST) Received: by mail-pg1-x531.google.com with SMTP id f9so5836582pgf.7 for ; Fri, 02 Dec 2022 18:34:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=0ZO9EQfENAwfe5IE7Ju6A4A1JevIMxb0gNE4/cvCkwk=; b=bZhPZLzaUJWjoiiQ0jtjANhKr0iyX1e0uNG49etJ1ffWLpKLJWwcXc84+guaypsl2A PjNDYu6sq7/NhXTAN1lBIp+zdvO9hB7UzRhMwC5VpDg0Hre5BtWmGUPdPFbZzI3sRhRf q4LqAwlrDWT2cQe+jeZ47UPoQQQDyEaLB+62w= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=0ZO9EQfENAwfe5IE7Ju6A4A1JevIMxb0gNE4/cvCkwk=; b=28idYw3h9IHwgyx7fXXK/SxTgIV19Ta/uSIhtg/qpFcIOugqNJHi59sw3SazkmF/ao PO+w7U8Z5G0GupOg5PZP/a+Xg4WMrSnGQsglh1EUCG2DFjYyPz9rns2+urYkfj55u4n9 jcXwDFqX+0FZiFzFZSuTj5lr8RgO/ipR5zo2WjotqkQwC3LW6IEByNLuIKO+AydDLKK0 Uv1Yfc7UXkSR292DVz53MO2pp87hifUzvTDF7r+/XqwbzIfCxPUL9Ed3GpBPX34z30sM Pn3ZkgMaAO/kwZhZQxbe14rUnGx0ntWZUCK3QFZOCXBTLwQLm1npEkA7AUpdKyCtco8S Aexw== X-Gm-Message-State: ANoB5pm+vb1WDjt4du6biP0E11GPBnOkFptIzZz39Oi6hSgWF7mqTl5I GzF5V4lbZydahw3C9zfEu3yVNQ== X-Google-Smtp-Source: AA0mqf4mKN6Zf9amKvtLE7G+OstIEuXv9ZvjBZH+Lsz+I5pkp/mARSH/gPpqWxQoI1ofPNBJm2wDiQ== X-Received: by 2002:aa7:9245:0:b0:571:3fb3:9b5f with SMTP id 5-20020aa79245000000b005713fb39b5fmr75199209pfp.86.1670034862394; Fri, 02 Dec 2022 18:34:22 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id ij19-20020a170902ab5300b0018685257c0dsm6213889plb.58.2022.12.02.18.34.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Dec 2022 18:34:22 -0800 (PST) Date: Fri, 2 Dec 2022 18:34:21 -0800 From: Kees Cook To: Rick Edgecombe 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 , Weijiang Yang , "Kirill A . Shutemov" , John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, akpm@linux-foundation.org, Andrew.Cooper3@citrix.com, christina.schimpe@intel.com, Yu-cheng Yu Subject: Re: [PATCH v4 15/39] mm: Introduce VM_SHADOW_STACK for shadow stack memory Message-ID: <202212021834.DC29FAC1@keescook> References: <20221203003606.6838-1-rick.p.edgecombe@intel.com> <20221203003606.6838-16-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221203003606.6838-16-rick.p.edgecombe@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Fri, Dec 02, 2022 at 04:35:42PM -0800, Rick Edgecombe wrote: > From: Yu-cheng Yu > > The x86 Control-flow Enforcement Technology (CET) feature includes a new > type of memory called shadow stack. This shadow stack memory has some > unusual properties, which requires some core mm changes to function > properly. > > A shadow stack PTE must be read-only and have _PAGE_DIRTY set. However, > read-only and Dirty PTEs also exist for copy-on-write (COW) pages. These > two cases are handled differently for page faults. Introduce > VM_SHADOW_STACK to track shadow stack VMAs. > > Tested-by: Pengfei Xu > Tested-by: John Allen > Signed-off-by: Yu-cheng Yu Reviewed-by: Kees Cook -- Kees Cook