From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752050AbYJ0Pc3 (ORCPT ); Mon, 27 Oct 2008 11:32:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751407AbYJ0PcS (ORCPT ); Mon, 27 Oct 2008 11:32:18 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:59923 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752852AbYJ0PcR (ORCPT ); Mon, 27 Oct 2008 11:32:17 -0400 Date: Mon, 27 Oct 2008 16:31:58 +0100 From: Ingo Molnar To: Arjan van de Ven Cc: linux-kernel@vger.kernel.org, Alan Cox , torvalds@linux-foundation.org, Matthew Wilcox , Jesse Barnes Subject: Re: RFC: [PATCH] resource: ensure MMIO exclusivity for device drivers Message-ID: <20081027153158.GJ5704@elte.hu> References: <20081022205656.184929ed@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081022205656.184929ed@infradead.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00,DNS_FROM_SECURITYSAGE autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] 0.0 DNS_FROM_SECURITYSAGE RBL: Envelope sender in blackholes.securitysage.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Arjan van de Ven wrote: > > From: Arjan van de Ven > Date: Wed, 22 Oct 2008 19:55:31 -0700 > Subject: [PATCH] resource: ensure MMIO exclusivity for device drivers > > Device drivers that use pci_request_regions() (and similar APIs) have a > reasonable expectation that they are the only ones accessing their device. > As part of the e1000e hunt, we were afraid that some userland (X or some > bootsplash stuff) was mapping the MMIO region that the driver thought it > had exclusively via /dev/mem or via various sysfs resource mappings. > > This patch adds the option for device drivers to cause their reserved > regions to be on the "banned from /dev/mem use" list, so now both kernel memory > and device-exclusive MMIO regions are banned. > NOTE: This is only active when CONFIG_STRICT_DEVMEM is set. > > In addition to the config option, a kernel parameter iomem=relaxed is > provided for the cases where developers want to diagnose, in the field, > drivers issues from userspace despite the drivers explicit request. > > Signed-off-by: Arjan van de Ven the concept looks fine to me - the stricter we are in this area the better IMO. Unless there are objections, i guess it's best to do this via the PCI tree? Ingo