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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1103AC433F5 for ; Mon, 11 Apr 2022 11:47:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344159AbiDKLt7 (ORCPT ); Mon, 11 Apr 2022 07:49:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60266 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244035AbiDKLt6 (ORCPT ); Mon, 11 Apr 2022 07:49:58 -0400 Received: from mail-qv1-xf36.google.com (mail-qv1-xf36.google.com [IPv6:2607:f8b0:4864:20::f36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8855445AE6 for ; Mon, 11 Apr 2022 04:47:43 -0700 (PDT) Received: by mail-qv1-xf36.google.com with SMTP id b17so12964819qvf.12 for ; Mon, 11 Apr 2022 04:47:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=clUQcx1FzZV9/CrN/0nkK9UIJB8E1uPK+JxCdawkISQ=; b=kNwzIcC1Tu/DEZHkYHyGdcusOmnfjVckBMYeTBJInUZNKkQIp7gU+TDBFqPHaQDF8C ish4dQ1qK/mzhm7R/SzHz8s69Kh9c8NELUPppb3lHDg7OZQJBf1mOZ0WtmtPVxwSJMr5 Wp7/jGKL8vEBh1loLIAUaAkW3JzzKCGEh5aXtrojCCqUxeB+P/MVC2w2bZ25+olfOK05 h+IwHZCmGP9St3KHgy8FQEGZUcNyGs4QFlrETm28cGL1TsEqOqtgDvKf3841oU6QgutU z7YRmqLG2+khtrBDCpa7g+wHDTZHUCCmAcMDKY6qxNM93WZZ8Jrb6eloV09OHCbi1HB8 0faw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=clUQcx1FzZV9/CrN/0nkK9UIJB8E1uPK+JxCdawkISQ=; b=l0dhEByNJhGdMEUAuPQv78FOK2gg+uKPe27XjmzcuYwlapgqA4uIb3grwzGaxsv9ky fnUnObPUfcECC1Y0s5YzrH9iJqc2g3yyO3Gf+zEF5ZV/7sD+HLtI9ENcyOwSFCnZLSE1 +KJ71jXp4B/yikU31XPBQjAhINM7Mqo0bvlfN4asJnceqDw7TVle40j43ixaZ39gTUJ1 s5ZeoCFJ6687iaaSxUao5swVfVg8wd45+QyB70ayu8emKqpP7aE5Y2VIbsR2aqzXRmZ7 sJ6/Pu2y/MCcDn8wOTxScgIsjQgcCJFwakU5WG0gXXPsCQJhqgT/70XPDeZc3i1moVTH dX5w== X-Gm-Message-State: AOAM530U+IeAPzjkZFsF7Wb//z/A3bY9e7B1+oCV0qJ80GQNdKPx/6AC C9W/X94N/4M0MQFonblWmUpZ2Q== X-Google-Smtp-Source: ABdhPJzkPU36RFVeX7u392AQJtCEsuNKiU4SzQV4oRld7cZwX2WbCGqmgaLTwpJDlwMCRDZTuq87aA== X-Received: by 2002:ad4:4eaf:0:b0:441:7ff6:f639 with SMTP id ed15-20020ad44eaf000000b004417ff6f639mr26561264qvb.73.1649677662733; Mon, 11 Apr 2022 04:47:42 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-162-113-129.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.113.129]) by smtp.gmail.com with ESMTPSA id 3-20020ac85903000000b002ee83037459sm2089230qty.42.2022.04.11.04.47.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Apr 2022 04:47:41 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1ndsWD-00Gixt-AP; Mon, 11 Apr 2022 08:47:41 -0300 Date: Mon, 11 Apr 2022 08:47:41 -0300 From: Jason Gunthorpe To: Lukas Wunner Cc: Lino Sanfilippo , peterhuewe@gmx.de, jarkko@kernel.org, =robh+dt@kernel.org, devicetree@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, stefanb@linux.ibm.com, p.rosenberger@kunbus.com Subject: Re: [PATCH 1/5] tpm: add functions to set and unset the tpm chips reset state Message-ID: <20220411114741.GA64706@ziepe.ca> References: <20220407111849.5676-1-LinoSanfilippo@gmx.de> <20220407111849.5676-2-LinoSanfilippo@gmx.de> <20220407142526.GW64706@ziepe.ca> <20220410171123.GA24453@wunner.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220410171123.GA24453@wunner.de> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Sun, Apr 10, 2022 at 07:11:23PM +0200, Lukas Wunner wrote: > On Thu, Apr 07, 2022 at 11:25:26AM -0300, Jason Gunthorpe wrote: > > On Thu, Apr 07, 2022 at 01:18:45PM +0200, Lino Sanfilippo wrote: > > > Currently it is not possible to set the tpm chips reset state from within > > > the driver. This is problematic if the chip is still in reset after the > > > system comes up. This may e.g. happen if the reset line is pulled into > > > reset state by a pin configuration in the device tree. > > > > This kind of system is badly misdesigned. > > > > TPM PCRs fundementally cannot work if the TPM reset line is under > > software control. > > Not every system which incorporates a TPM wants to use or is even capable > of measuring software state of any kind or perform secure boot. > > Those systems may merely want to use the TPM to store key material. Then maybe the TPM driver should make it clear somehow that the PCRs don't work in these systems. It is really dangerous to add capabilities like this that should never, ever be used in sanely designed systems. Jason