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 92AD9C43382 for ; Fri, 28 Sep 2018 16:27:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C43E20684 for ; Fri, 28 Sep 2018 16:27:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C43E20684 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 S1729513AbeI1Wvs (ORCPT ); Fri, 28 Sep 2018 18:51:48 -0400 Received: from gate.crashing.org ([63.228.1.57]:40195 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727349AbeI1Wvs (ORCPT ); Fri, 28 Sep 2018 18:51:48 -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 w8SGQShG028469; Fri, 28 Sep 2018 11:26:28 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id w8SGQQr0028459; Fri, 28 Sep 2018 11:26:26 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Fri, 28 Sep 2018 11:26:25 -0500 From: Segher Boessenkool To: Michael Ellerman Cc: Christophe LEROY , Benjamin Herrenschmidt , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 1/2] powerpc/32: add stack protector support Message-ID: <20180928162625.GT23155@gate.crashing.org> References: <20180926191615.GO23155@gate.crashing.org> <220fbef8-429c-9485-d10e-c1eaa989918d@c-s.fr> <20180927074525.GQ23155@gate.crashing.org> <28451b6a-e302-691e-ee28-16521997fb07@c-s.fr> <8736ttu6fs.fsf@concordia.ellerman.id.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8736ttu6fs.fsf@concordia.ellerman.id.au> 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 Fri, Sep 28, 2018 at 10:56:07PM +1000, Michael Ellerman wrote: > The problem of low entropy at boot on systems without a good hardware > source is sort of unsolvable. > > As you say it's up to the core kernel/random code, we shouldn't be > trying to do anything tricky in the arch code. > > You don't want your system to take 3 hours to boot because it's waiting > for entropy for the stack canary. > > If we can update the canary later once the entropy pool is setup that > would be ideal. Yup, I agree with all that. But we should *also* not say "oh, there may be cases where we cannot do the right thing, so just do not even try, ever, anywhere". Segher