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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 A6A89C433E0 for ; Wed, 20 May 2020 12:11:44 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CC62F20758 for ; Wed, 20 May 2020 12:11:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="nZVXc9EK"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=chronox.de header.i=@chronox.de header.b="L72MUnMJ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CC62F20758 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chronox.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=w75HCSQ4re20bKp5jiRl6wESbYJuX4yAA2a5ENEVq7w=; b=nZVXc9EKejCFKe FaibT5lp/ltMByOmXZyRx89r+1RLbzdO6Lu4dT8tJVHiHqL3PhG2sekWf5QC75XL6w8j0O8353IW5 yapyd4Yx9PdEO/GU/8mL5xlG78KnPNscT55plB1SSosV1TIwrxJBfrZGQamXxdnYJb6xz86yUYxdr 0IlctyZ6wo7ME6aRKurAWYR2RB/5+NMr7xEEwB4rIf0frnOKPchERmDOSKqx7HDgUDYHZNDGK8I9A yMaxdN9L+eClW45GVbh47gB2N9zGDyuk/cyCzG0+NtOQVzQASRdwmpKKhdKBuB1gHOglsz0m0QhQe Pf7l+zLf+KZ8pzQskhkQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jbNZX-0001jH-EI; Wed, 20 May 2020 12:11:43 +0000 Received: from mo6-p02-ob.smtp.rzone.de ([2a01:238:20a:202:5302::12]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jbNZU-0001hX-1L for linux-arm-kernel@lists.infradead.org; Wed, 20 May 2020 12:11:41 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1589976698; s=strato-dkim-0002; d=chronox.de; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: X-RZG-CLASS-ID:X-RZG-AUTH:From:Subject:Sender; bh=dxK4Z+9yHO4jSPBzrsgC+jQ7JJM6/ROZjhK04+QSi/s=; b=L72MUnMJGFYtao72d82KD8w3lzOPdbioUYLkp8jzq1rkP8LPTPGQINrztVWhbZja3H xsIXF4urN/EuL71PRwrVv/nhhPHtui0/ZeekRj1pHSsyWgw9dR3h4dtZMGwq8XxV4RNZ 70tM3Sg8+qc/kFulMvXp6GOTCWb164QJOXQwmhlU2tMmRGV7beGTOmhFVXkbAyye0qhL wAkcHsG7JP/R+DYkMhCidWduW7NBT6kuIM4bXc5osDvfHX/hAwigeZU1AYg/HwXcpGQK wR6Je9UsID12ZjQ75Rj2kl204l1YJLVKlD+Pz7da6a0ZdP7Z9Wt59iEtG7PP7lzPEawY tsAA== X-RZG-AUTH: ":P2ERcEykfu11Y98lp/T7+hdri+uKZK8TKWEqNyiHySGSa9k9xmwdNnzGHXPbI/Sc5g==" X-RZG-CLASS-ID: mo00 Received: from tauon.chronox.de by smtp.strato.de (RZmta 46.7.0 DYNA|AUTH) with ESMTPSA id k09005w4KCBZ5LX (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Wed, 20 May 2020 14:11:35 +0200 (CEST) From: Stephan Mueller To: Krzysztof Kozlowski Subject: Re: [PATCH v2 1/2] hwrng: iproc-rng200 - Set the quality value Date: Wed, 20 May 2020 14:11:34 +0200 Message-ID: <3322411.JsYv2Y6bm7@tauon.chronox.de> In-Reply-To: References: <15745285.MnsZKaK4VV@tauon.chronox.de> <2041475.ybOAuNAZB8@tauon.chronox.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200520_051140_663947_865F4AD1 X-CRM114-Status: GOOD ( 20.18 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Florian Fainelli , Herbert Xu , Arnd Bergmann , Matthias Brugger , Greg Kroah-Hartman , Matt Mackall , Lukasz Stelmach , Scott Branden , "linux-kernel@vger.kernel.org" , "linux-samsung-soc@vger.kernel.org" , Bartlomiej Zolnierkiewicz , Kukjin Kim , bcm-kernel-feedback-list@broadcom.com, Stefan Wahren , Ray Jui , Markus Elfring , linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Am Mittwoch, 20. Mai 2020, 14:00:01 CEST schrieb Krzysztof Kozlowski: Hi Krzysztof, > On Wed, 20 May 2020 at 13:53, Stephan Mueller wrote: > > > > That said, the illustrated example is typical for hardware RNGs. Yet > > > > it is never guaranteed to work that way. Thus, if you can point to > > > > architecture documentation of your specific hardware RNGs showing that > > > > the data read from the hardware is pure unconditioned noise data, then > > > > I have no objections to the patch. > > > > > > I can tell for sure that this is the case for exynos-trng[1]. > > > > So you are saying that the output for the exynos-trng is straight from a > > ring oscillator without any post-processing of any kind? > > Hi, > > I think we will never be able to state this because the manual is > quite limited in sharing internals. What the driver does and probably > Lukasz wanted to say is that there is "post processing" block and > feature which can be disabled. The manual is saying the TRNG block > generates random data from thermal noise but not how much in a direct > way. There could be some simple post-processing or not (except the one > able to on/off). Also manual says this post processing block is there > to remove statistical weakness from the TRNG block. To me it does not > prove enough that raw data is really raw... Unterstood, but can't that statement be added to the commit message? > > Best regards, > Krzysztof Ciao Stephan _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel