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=-7.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 EF4BDC432C3 for ; Tue, 3 Dec 2019 10:17:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C7436206DF for ; Tue, 3 Dec 2019 10:17:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575368261; bh=5ySN3e5aUDRbhiQLCPyxs/vWIneLIy4KAn4LJwCq6Qs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=vutbrCQqJ2FutkSrC/0gDwXC+haVN5OydYfved29hVo15F9b2pErHFa3zHLOmNSic iRFYo7v2pu3XFM3AMPDnnteDeCOI8FsHWX077gVw01lQq87asI6k7HFC1VrJVsqwv/ aQHNQBQOnaqaUNAdXkawvUK9lN0sPkYESLAVF388= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725848AbfLCKRl (ORCPT ); Tue, 3 Dec 2019 05:17:41 -0500 Received: from mail.kernel.org ([198.145.29.99]:34238 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725773AbfLCKRl (ORCPT ); Tue, 3 Dec 2019 05:17:41 -0500 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 CBC562068E; Tue, 3 Dec 2019 10:17:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575368260; bh=5ySN3e5aUDRbhiQLCPyxs/vWIneLIy4KAn4LJwCq6Qs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kMScm8GSzW4KeDWfSNSKzpGeRbVVCFvwkHxu3o+HncYmc1ZMD9uM8+flajxYG3OSj /3ciRNYMo3BiZw+E7eMtEjiYd7+acvkY5XsvqH5JshHzGPG8kNDM9bW1JHSNuNlDOg pVuRor6iCytI5GH4UIuH6jiB6DLUtCW0mKX2yae8= Date: Tue, 3 Dec 2019 10:17:20 +0000 From: Will Deacon To: Marc Zyngier Cc: Ard Biesheuvel , Neal Liu , Catalin Marinas , Lars Persson , Mark Rutland , DTML , Herbert Xu , wsd_upstream , Sean Wang , Linux Kernel Mailing List , Rob Herring , Crystal Guo =?utf-8?B?KOmDreaZtik=?= , "linux-crypto@vger.kernel.org" , Matt Mackall , Matthias Brugger , "linux-mediatek@lists.infradead.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH v5 3/3] hwrng: add mtk-sec-rng driver Message-ID: <20191203101720.GD6815@willie-the-truck> References: <1574864578-467-1-git-send-email-neal.liu@mediatek.com> <1574864578-467-4-git-send-email-neal.liu@mediatek.com> <1575027046.24848.4.camel@mtkswgap22> <20191202191146.79e6368c@why> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191202191146.79e6368c@why> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Mon, Dec 02, 2019 at 07:11:46PM +0000, Marc Zyngier wrote: > On Mon, 2 Dec 2019 16:12:09 +0000 > Ard Biesheuvel wrote: > > > (adding some more arm64 folks) > > > > On Fri, 29 Nov 2019 at 11:30, Neal Liu wrote: > > > > > > On Fri, 2019-11-29 at 18:02 +0800, Lars Persson wrote: > > > > Hi Neal, > > > > > > > > On Wed, Nov 27, 2019 at 3:23 PM Neal Liu wrote: > > > > > > > > > > For MediaTek SoCs on ARMv8 with TrustZone enabled, peripherals like > > > > > entropy sources is not accessible from normal world (linux) and > > > > > rather accessible from secure world (ATF/TEE) only. This driver aims > > > > > to provide a generic interface to ATF rng service. > > > > > > > > > > > > > I am working on several SoCs that also will need this kind of driver > > > > to get entropy from Arm trusted firmware. > > > > If you intend to make this a generic interface, please clean up the > > > > references to MediaTek and give it a more generic name. For example > > > > "Arm Trusted Firmware random number driver". > > > > > > > > It will also be helpful if the SMC call number is configurable. > > > > > > > > - Lars > > > > > > Yes, I'm trying to make this to a generic interface. I'll try to make > > > HW/platform related dependency to be configurable and let it more > > > generic. > > > Thanks for your suggestion. > > > > > > > I don't think it makes sense for each arm64 platform to expose an > > entropy source via SMC calls in a slightly different way, and model it > > as a h/w driver. Instead, we should try to standardize this, and > > perhaps expose it via the architectural helpers that already exist > > (get_random_seed_long() and friends), so they get plugged into the > > kernel random pool driver directly. > > Absolutely. I'd love to see a standard, ARM-specified, virtualizable > RNG that is abstracted from the HW. Same here. I hacked up some initial code for doing this with KVM [1], but I'd much rather it was part of a standard service specification so that we could use the same interface for talking to the firmware and the hypervisor. Will [1] https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=kvm/hvc