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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 2FAD7ECE560 for ; Mon, 17 Sep 2018 16:50:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA61B214DC for ; Mon, 17 Sep 2018 16:50:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DA61B214DC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728692AbeIQWSJ (ORCPT ); Mon, 17 Sep 2018 18:18:09 -0400 Received: from gate.crashing.org ([63.228.1.57]:58395 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726795AbeIQWSJ (ORCPT ); Mon, 17 Sep 2018 18:18:09 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id w8HGnElO009413; Mon, 17 Sep 2018 11:49:14 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id w8HGnC3Z009392; Mon, 17 Sep 2018 11:49:12 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 17 Sep 2018 11:49:11 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] powerpc/32: stack protector: change the canary value per task Message-ID: <20180917164911.GK23155@gate.crashing.org> References: <9f7efcc085685717bb4c7b3a575138a1a1cd15ed.1537186089.git.christophe.leroy@c-s.fr> <7bd67c4ccdd202f2125b7fc0ed0332d0d020690b.1537186089.git.christophe.leroy@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7bd67c4ccdd202f2125b7fc0ed0332d0d020690b.1537186089.git.christophe.leroy@c-s.fr> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 17, 2018 at 12:15:08PM +0000, Christophe Leroy wrote: > I would have liked to use -mstack-protector-guard=tls -mstack-protector-guard-reg=r2 > -mstack-protector-guard-offset=offsetof(struct task_struct, stack_canary) but I have > not found how set the value of offsetof(struct task_struct, stack_canary) in Makefile. By far the easiest is to have the canary at a fixed offset from r2. Segher