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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 E79FCC33CB1 for ; Wed, 15 Jan 2020 09:16:34 +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 B9C292081E for ; Wed, 15 Jan 2020 09:16:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="frJqtwnq"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="CNQytM71" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B9C292081E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=w6s56OXb1Bm1LpIytYW3KeKE/2V9xmk/mQssWfZPYIQ=; b=frJqtwnqAix7N0 FTdCW14GSkLHkYCq9S7GOYO01sTcIsoHm3A77rfjR0nRcV/mB1E0QxYAgLhxURtavr7BAU29ftCQt mKpWuKqLVi090Up6t9M7E8NErAKD4VppxTuUPWfq3CuObnR0YVL6daZK2ZUAHLtjOjPQ8gGdDp5Z+ 9k28tfqq0pnr0TPNk5t8i3w62lyhuZ3tlvrFnB6yhK1nk88eQBloKqDOzGYh1+P8uSDacpHxr0ZJq 9QX8JC2T+FbT2Y4ihtZ3zD1DCbYg98xqqSvOjXSt14a5wmZ8dSIQhPiGxIcFX1Pp7b6MCNNSUZtnn zrvHSpNCdOsK5Lv6ZoVw==; 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 1iremq-0002VS-0S; Wed, 15 Jan 2020 09:16:28 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iremi-0002Ut-Su for linux-arm-kernel@lists.infradead.org; Wed, 15 Jan 2020 09:16:26 +0000 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 66F412081E; Wed, 15 Jan 2020 09:16:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579079780; bh=kcJDlaPpWouyHV8AgG7O+oO5lQc8Hu15HbF+Q1786RM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=CNQytM71xMAm2y5TPnTp7W+HpJbjBHYl7AhCQK0HQWQlAt8lW3/upHsgNXB5vUhi8 w50YekGKEXdQJiksvxdl52sVRJ6gbgVJ+lNUZLIOWNh4aptl8kmbXOJ4NEg9dgWOLG +f8nMns4B1nFvUZecPW3RIHBA5PRmi05N0oJS0cw= Date: Wed, 15 Jan 2020 09:16:16 +0000 From: Will Deacon To: Ard Biesheuvel Subject: Re: [PATCH v10 2/3] arm64: random: Add data to pool from setup_arch() Message-ID: <20200115091615.GA21692@willie-the-truck> References: <20200110122341.8445-1-broonie@kernel.org> <20200110122341.8445-3-broonie@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200115_011620_955267_5CE9BF53 X-CRM114-Status: GOOD ( 21.32 ) 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: Mark Rutland , Catalin Marinas , Mark Brown , Richard Henderson , linux-arm-kernel 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 On Wed, Jan 15, 2020 at 08:48:46AM +0100, Ard Biesheuvel wrote: > On Fri, 10 Jan 2020 at 13:23, Mark Brown wrote: > > > > Since the arm64 ARCH_RANDOM implementation is not available until > > cpufeature has determined the system capabilities it can't be used by > > the generic random code to initialize the entropy pool for early use. > > Instead explicitly add some data to the pool from setup_arch() if the > > boot CPU supports v8.5-RNG, this is the point recommended by the generic > > code. > > > > Note that we are only adding data here, it will be mixed into the pool > > but won't be credited as entropy. There are currently no suitable > > interfaces for that at present - extending the random code to provide > > those will be done as a future step. Providing data is better than not > > doing so as it will still provide an increase in variation in the output > > from the random code and there will be no impact on the rate at which > > entropy is credited compared to what we have without this patch. > > > > This is slightly unfortunate, as this way, we lose the ability to use > random.trust_cpu=1 to get the entropy credited and initialize CRNG > early. Agreed. Do you think we should wait for that support before merging the series? Given that I don't know of any CPUs implementing this extension, we can probably afford not to rush this in. Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel