Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755281AbdC1RnW convert rfc822-to-8bit (ORCPT ); Tue, 28 Mar 2017 13:43:22 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:34890 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751954AbdC1RnU (ORCPT ); Tue, 28 Mar 2017 13:43:20 -0400 Date: Tue, 28 Mar 2017 20:43:08 +0300 From: Krzysztof Kozlowski To: Stephan =?utf-8?Q?M=C3=BCller?= Cc: PrasannaKumar Muralidharan , Kukjin Kim , Javier Martinez Canillas , Matt Mackall , Herbert Xu , "David S. Miller" , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-crypto@vger.kernel.org, Bartlomiej Zolnierkiewicz , Arnd Bergmann , Olof Johansson Subject: Re: [PATCH v3 1/3] crypto: hw_random - Add new Exynos RNG driver Message-ID: <20170328174308.lwcogz2ae3bwnumr@kozik-lap> References: <20170325162654.3827-1-krzk@kernel.org> <1564458.pWTRdRYEuG@positron.chronox.de> <20170328164824.3qjaojqzf2riwpqj@kozik-lap> <93183073.lKE0KLq0vu@tauon.atsec.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8BIT In-Reply-To: <93183073.lKE0KLq0vu@tauon.atsec.com> User-Agent: Mutt/1.6.2-neo (2016-08-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 863 Lines: 24 On Tue, Mar 28, 2017 at 07:41:47PM +0200, Stephan Müller wrote: > Am Dienstag, 28. März 2017, 18:48:24 CEST schrieb Krzysztof Kozlowski: > > Hi Krzysztof, > > > I tested a little bit and: > > 1. Seeding with some value > > 2. generating random, > > 3. kcapi_rng_destroy+kcrng_init, (I cannot do a hardware reset except > > reboot of entire system) > > 4. seeding with the same value as in (1) - different random numbers. > > > > Doing a system reboot and repeating above - different random numbers > > (all are different: step (2) and in (4)). > > > > Your test case also produces different random values every time. > > Then I would assume that simply adding an outer loop to your for() loop to > inject seed larger than the minimum required seed size should be fine. Yes, makes sense. I'll send an updated version of patch. Best regards, Krzysztof