From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id bwiAD4VxGludNQAAmS7hNA ; Fri, 08 Jun 2018 12:07:59 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 8795D608B8; Fri, 8 Jun 2018 12:07:59 +0000 (UTC) Authentication-Results: smtp.codeaurora.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="tGzd4d/Y" X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id 1C5A1605A5; Fri, 8 Jun 2018 12:07:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 1C5A1605A5 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752754AbeFHMH4 (ORCPT + 25 others); Fri, 8 Jun 2018 08:07:56 -0400 Received: from mail-lf0-f67.google.com ([209.85.215.67]:36390 "EHLO mail-lf0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751604AbeFHMHy (ORCPT ); Fri, 8 Jun 2018 08:07:54 -0400 Received: by mail-lf0-f67.google.com with SMTP id u4-v6so19732108lff.3; Fri, 08 Jun 2018 05:07:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=1tnaKvjh8k1b0CZs+mpV6H2ERiDZglxlgKGfZM67iks=; b=tGzd4d/YMVvaSLnphrnWlAtXYtOXzxjViYxIVSFshVg51X7jc5JMjc+FQCS2eM7AjB biMadR44uPO2X8jDuyBdZKjhGOyTOiB/ZJTiMKu1cOE7pRZVAOUDGiPYJbX26xdwDLZn cgItXiVxgt3N3EEW5AfWCchyrMg1VpARvPP6A84HwKxMqjO3qLrwHoMN3vdk0Ijk/dIL vCMAymJJi0TqkC9PhavysmPOwPwVTbEjuHHG5aJK/VWUdp0x2qkNmFA8QepT6ILQJ9uE 3F8IJXRmWaAkmgw73tkCJA46IF9QksomFLe/f0zlzi3fQPVr2tQgV0KXZOUhwxMLSHx3 t2Rw== 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:user-agent; bh=1tnaKvjh8k1b0CZs+mpV6H2ERiDZglxlgKGfZM67iks=; b=l1Ve1D6fC9YMM5PNBMWjoWc4zIE5VvKY7wrxY4h9eWbm12eDHazKSSLAVEWigwazun XsxncuOGIXWJdcFySjbkBxCkWsrnHKuEf7GVZzE8pHBpFWq5jt/xBdhsbZMECEfQ2Jwq bWCmPJs4tJHryaljfuw7nk4Lj3v9cizB8mp4jK3W7Yn7wSIWqADPl3Io7RwwWb7GfMKt YTeWFbXL/5kXRdNLYttD5E0NANDbfXI/bTlQXBuh9UlpDiPEAjE7B4EadDY/d/MRxXAw orCdy23J3ssPaJIe9DGafqXQ4RSwr+AGG3nOLZYoTT8hexfYIIZP4hsy1zXokPg5B5XV cucg== X-Gm-Message-State: APt69E2Qo/4wtNX3RqX6QJ0DNye8jK8ORzBcg38Vxdtqufks4IBJ8SAe sxoS9eGXfUydx3R2g9VL4DBxAILp X-Google-Smtp-Source: ADUXVKJkmRmWk3+39u2FngCtJWEjeY7gwXnY65o4alSu9muuxLfwP+LFor6VV/4O2YsgkS72n3VNlA== X-Received: by 2002:a19:b587:: with SMTP id g7-v6mr4019082lfk.144.1528459672277; Fri, 08 Jun 2018 05:07:52 -0700 (PDT) Received: from uranus.localdomain ([5.18.103.226]) by smtp.gmail.com with ESMTPSA id j64-v6sm2245121lfe.64.2018.06.08.05.07.51 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 08 Jun 2018 05:07:51 -0700 (PDT) Received: by uranus.localdomain (Postfix, from userid 1000) id D8A3C460756; Fri, 8 Jun 2018 15:07:50 +0300 (MSK) Date: Fri, 8 Jun 2018 15:07:50 +0300 From: Cyrill Gorcunov To: Andy Lutomirski Cc: Yu-cheng Yu , Florian Weimer , Dmitry Safonov , LKML , linux-doc@vger.kernel.org, Linux-MM , linux-arch , X86 ML , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , "H. J. Lu" , "Shanbhogue, Vedvyas" , "Ravi V. Shankar" , Dave Hansen , Jonathan Corbet , Oleg Nesterov , Arnd Bergmann , mike.kravetz@oracle.com Subject: Re: [PATCH 03/10] x86/cet: Signal handling for shadow stack Message-ID: <20180608120750.GB2525@uranus> References: <20180607143807.3611-1-yu-cheng.yu@intel.com> <20180607143807.3611-4-yu-cheng.yu@intel.com> <20180607200714.GA2525@uranus> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 07, 2018 at 01:57:03PM -0700, Andy Lutomirski wrote: ... > > > > I didn't read the whole series of patches in details > > yet, hopefully will be able tomorrow. Thanks Andy for > > CC'ing! > > We have uc_flags. It might be useful to carve out some of the flag > space (24 bits?) to indicate something like the *size* of sigcontext > and teach the kernel that new sigcontext fields should only be parsed > on sigreturn() if the size is large enough. Yes, this should do the trick.