Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752180AbcJISGR (ORCPT ); Sun, 9 Oct 2016 14:06:17 -0400 Received: from mga09.intel.com ([134.134.136.24]:32736 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751439AbcJISGQ (ORCPT ); Sun, 9 Oct 2016 14:06:16 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,467,1473145200"; d="scan'208";a="17861974" Date: Sun, 9 Oct 2016 21:06:13 +0300 From: Jarkko Sakkinen To: Jason Gunthorpe 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: <20161009180613.GA26794@intel.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> <20161009164905.GA12551@obsidianresearch.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161009164905.GA12551@obsidianresearch.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1971 Lines: 49 On Sun, Oct 09, 2016 at 10:49:05AM -0600, Jason Gunthorpe wrote: > 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. Yes, that's what the point I tried to make in my response in the part that is not quoted here. /Jarkko