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=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 43BCEC3F68F for ; Thu, 23 Jan 2020 01:53:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1ACE124673 for ; Thu, 23 Jan 2020 01:53:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=aj.id.au header.i=@aj.id.au header.b="qsshw+6M"; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="DN6OGW/S" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725933AbgAWBxx (ORCPT ); Wed, 22 Jan 2020 20:53:53 -0500 Received: from new3-smtp.messagingengine.com ([66.111.4.229]:36509 "EHLO new3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725911AbgAWBxw (ORCPT ); Wed, 22 Jan 2020 20:53:52 -0500 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailnew.nyi.internal (Postfix) with ESMTP id D8A6A6D87; Wed, 22 Jan 2020 20:53:51 -0500 (EST) Received: from imap2 ([10.202.2.52]) by compute4.internal (MEProxy); Wed, 22 Jan 2020 20:53:51 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aj.id.au; h= mime-version:message-id:in-reply-to:references:date:from:to:cc :subject:content-type; s=fm1; bh=ujZkvtF9majEmku/Gxs4rZoUakuhfzp hD8ol/URHilo=; b=qsshw+6MxBNBzlpsVfUQJvzPlg1mYf034IOSuoePEBVtHNN ehE++KC/RbpuXEATKpEmSmmnCDp1WFqj7zSqqmQaLd1P/XsqZQpuulLziDntGcEi Zl24Kqe7K5broi96LBy5wFhNHIwNwXyEvvLMp9EqS/6nsF/A1gBvZHTJSR+ZCTq8 jWvOnveizc8TEi4FFYrl6/b6ptzaBi4KjnepiyPNrzEAfiFHFKqfnudBBcXcd+Vl 1Q6FBERhKPJL2nFTyOkGQPs5b8QvcnoAzkZn2Br4y2nAbo2Du0g3lZgqPa6+xHCl fQ1vp8LM4m3v8l5So9ZZ5kwWz2cHB6+LstSxB/A== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=ujZkvt F9majEmku/Gxs4rZoUakuhfzphD8ol/URHilo=; b=DN6OGW/SMqdXSI8jjtOzO2 pGGVbrE9JRzGYsU3PcIOiobOZj1lO91DbwO31coNzfzM79yWYDsfaH1z/FrE4pOw K1cSpis2xl8x04ImWo4vZfPpa6T2R2jbu6OXfyod2Hi9b39uZVhOzKR8R0hG5A/N pUc9U3pDRSgmijNImgE+OK81Ohewqo/E9GWP5dUvTYMhLzWSWl9uJyv9P6EMFbBA g9nO1fp1IBXJUNrvbSrHxWw/xir2jOWs+Mub7vIioYbyUbYPRtBaAkBrcb7BhOTB fSY/RMQ+yIIyPB8wd9BHAvboR+hwUPsKTXljq72DPmDKDp0NAzJYOwmNdvlrtwAA == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedugedrvddugdefiecutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenuc fjughrpefofgggkfgjfhffhffvufgtsehttdertderredtnecuhfhrohhmpedftehnughr vgifucflvghffhgvrhihfdcuoegrnhgurhgvfiesrghjrdhiugdrrghuqeenucevlhhush htvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhrohhmpegrnhgurhgvfiesrghj rdhiugdrrghu X-ME-Proxy: Received: by mailuser.nyi.internal (Postfix, from userid 501) id 7543AE00A2; Wed, 22 Jan 2020 20:53:50 -0500 (EST) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.1.7-754-g09d1619-fmstable-20200113v1 Mime-Version: 1.0 Message-Id: <575811fd-24ca-409c-8d33-c2152ee401d7@www.fastmail.com> In-Reply-To: <4446ffb694c7742ca9492c7360856789@neuralgames.com> References: <20200120150113.2565-1-linux@neuralgames.com> <4446ffb694c7742ca9492c7360856789@neuralgames.com> Date: Thu, 23 Jan 2020 12:23:29 +1030 From: "Andrew Jeffery" To: "Oscar A Perez" , "Joel Stanley" Cc: "Matt Mackall" , "Herbert Xu" , "Rob Herring" , "Mark Rutland" , "Linux Crypto Mailing List" , devicetree , "Linux ARM" , linux-aspeed , "Linux Kernel Mailing List" Subject: Re: [PATCH 1/2] hwrng: Add support for ASPEED RNG Content-Type: text/plain Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org > Thanks for reviewing the patch. > > The RNG on Aspeed hardware allows eight different modes for combining > its four internal Ring Oscillators that together generate a stream of > random bits. However, the timeriomem-rng driver does not allow for mode > selection so, the Aspeed RNG with this generic driver runs always on > mode 'seven' (The default value for mode according to the AspeedTech > datasheets). > > I've performed some testings on this Aspeed RNG using the NIST > Statistical Test Suite (NIST 800-22r1a) and, the results I got show that > the default mode 'seven' isn't producing the best entropy and linear > rank when compared against the other modes available on these SOCs. On > the other hand, the driver that I'm proposing here allows for mode > selection which would help improve the random output for those looking > to get the best out of this Aspeed RNG. Have you published the data and results of this study somewhere? This really should be mentioned in the commit message as justification for not using timeriomem-rng. Andrew