Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751882AbcJIQtQ (ORCPT ); Sun, 9 Oct 2016 12:49:16 -0400 Received: from quartz.orcorp.ca ([184.70.90.242]:38986 "EHLO quartz.orcorp.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751199AbcJIQtP (ORCPT ); Sun, 9 Oct 2016 12:49:15 -0400 Date: Sun, 9 Oct 2016 10:49:05 -0600 From: Jason Gunthorpe To: Jarkko Sakkinen Cc: Peter Huewe , Marcel Selhorst , "moderated list:TPM DEVICE DRIVER" , open list Subject: Re: [PATCH RFC 1/3] tpm_crb: expand struct crb_control_area to struct crb_regs Message-ID: <20161009164905.GA12551@obsidianresearch.com> References: <1475972112-2819-1-git-send-email-jarkko.sakkinen@linux.intel.com> <1475972112-2819-2-git-send-email-jarkko.sakkinen@linux.intel.com> <20161009014256.GA8210@obsidianresearch.com> <20161009093818.GG31891@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161009093818.GG31891@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Broken-Reverse-DNS: no host name found for IP address 10.0.0.151 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1722 Lines: 45 On Sun, Oct 09, 2016 at 12:38:18PM +0300, Jarkko Sakkinen wrote: > On Sat, Oct 08, 2016 at 07:42:56PM -0600, Jason Gunthorpe wrote: > > On Sun, Oct 09, 2016 at 03:15:09AM +0300, Jarkko Sakkinen wrote: > > > + ctrl = crb_map_res(dev, priv, &io_res, buf->control_address, > > > + sizeof(struct crb_regs) - > > > + offsetof(struct crb_regs, ctrl_req)); > > > + if (IS_ERR(ctrl)) > > > + return PTR_ERR(ctrl); > > > + > > > + /* The control area always overrlaps IO memory mapped from the ACPI > > > + * object with CRB start only devices. Thus, this is perfectly safe. > > > + */ > > > + priv->regs = (void *)((unsigned long)ctrl - > > > + offsetof(struct crb_regs, ctrl_req)); > > > > Hum. No, this makes bad assumptions about the structure of iomapping. > > > > The map itself needs to be done with the adjustment: > > > > ctrl = crb_map_res(dev, priv, &io_res, buf->control_address - > > offsetof(struct crb_regs, ctrl_req), > > sizeof(struct crb_regs)); > > That would be wrong address for the control area as it does not start > from the beginning of CRB registers. Of course, I just pointed out what the map call should look like Something like this priv->regs = crb_map_res(dev, priv, &io_res, buf->control_address - offsetof(struct crb_regs, ctrl_req), sizeof(struct crb_regs)); ctrl = &priv->regs.ctrl_req; > I think the crb_map_io and crb_map_res are too generic. Better way to do > things would be to validate that assumptions for these two cases hold. If the driver is going to be using a negative offset like this, then it very much should validate the assumptions before doing it. and not even map these regsiters if they are not supported by hardware. Jason