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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 73FB1C636C8 for ; Tue, 20 Jul 2021 23:20:29 +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 3A2BA6101E for ; Tue, 20 Jul 2021 23:20:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A2BA6101E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:Cc: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=D1cossZVZxgKzoNd+mp+Qr7uWHrBz5TkrZD+qDScgUY=; b=vobzdvYz1TAQlf xmjst4SLCTkfojZoDgE6jMEkZ7dZG+WtEkMIp4icotNVx8/gB9k2CQaP+FvQivmtc1h3+ywFq64d6 FmnqlLO1ifYy9cPgHHwcgAEZf8IkqTPWjWeT70xDd7fMu7ixhTgrulOKjHyhJmM2KXAf3zCg98DzW dxiC8H2QIjOOMHJPXMMDsqMcI4E2jJDTWok9B1bswtwqUKyU+95M1a8Vf0kooC9pnaPKR9560wlEi WgoN+0OFKn+HDOnJ6BLERmWACa+tgEq6gDFGaMotpLQqQwttLVgTeWCx6sfLH0yFw4MBbD56BqH6i JAK9xTlAYCTEglHP1TXA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m5z0f-00E8Hr-Qz; Tue, 20 Jul 2021 23:18:45 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1m5z0c-00E8HK-O4 for linux-arm-kernel@lists.infradead.org; Tue, 20 Jul 2021 23:18:44 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 22F281FB; Tue, 20 Jul 2021 16:18:40 -0700 (PDT) Received: from slackpad.fritz.box (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 855D03F694; Tue, 20 Jul 2021 16:18:38 -0700 (PDT) Date: Wed, 21 Jul 2021 00:18:03 +0100 From: Andre Przywara To: Benjamin Herrenschmidt Cc: Ard Biesheuvel , Matt Mackall , Herbert Xu , Linux Crypto Mailing List , Linux ARM , Linux Kernel Mailing List , Mark Brown , Will Deacon , Ali Saidi , Jon Nettleton Subject: Re: [PATCH v2] hwrng: Add Arm SMCCC TRNG based driver Message-ID: <20210721001803.303dfba1@slackpad.fritz.box> In-Reply-To: References: <20210720152158.31804-1-andre.przywara@arm.com> <20210720171631.071f84f5@slackpad.fritz.box> Organization: Arm Ltd. X-Mailer: Claws Mail 3.17.1 (GTK+ 2.24.31; x86_64-slackware-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210720_161842_888484_1F22FB1C X-CRM114-Status: GOOD ( 15.98 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 21 Jul 2021 08:02:42 +1000 Benjamin Herrenschmidt wrote: Hi, > On Tue, 2021-07-20 at 17:16 +0100, Andre Przywara wrote: > > Yes, a similar idea was already brought up before. I think there is even > > the potential for something like an artificial SMCCC "bus", where those > > services presentable as devices could be auto-detected (by checking > > known function IDs), the respective drivers would then probe > > automatically? > > Sounds like a boot time killer... How so? To be clear, at the moment there is basically just the TRNG service we would probe for, maybe FF-A, then adding as we go. But in any case it would be just a handful, and querying is very quick (SMC/HVC, then just a switch/case on the other side, and ERET). Is there any particular scenario you are concerned about? Quick starting guests? > can we instead describe them in DT and/or ACPI ? I think part of the idea of SMCCC is that it does NOT need firmware advertisement, but can instead be discovered, through a safe interface. Cheers, Andre _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel