From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753829AbdHRAbF (ORCPT ); Thu, 17 Aug 2017 20:31:05 -0400 Received: from www.llwyncelyn.cymru ([82.70.14.225]:57936 "EHLO fuzix.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752872AbdHRAbD (ORCPT ); Thu, 17 Aug 2017 20:31:03 -0400 Date: Fri, 18 Aug 2017 01:30:47 +0100 From: Alan Cox To: "Luck, Tony" Cc: "Rafael J. Wysocki" , Len Brown , Boris Petkov , Tyler Baicar , Punit Agrawal , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ACPI / sysfs: Extend ACPI sysfs to provide access to boot error region Message-ID: <20170818013047.427e38b7@alans-desktop> In-Reply-To: <20170817213946.16939-1-tony.luck@intel.com> References: <20170817213946.16939-1-tony.luck@intel.com> Organization: Intel Corporation X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 17 Aug 2017 14:39:46 -0700 "Luck, Tony" wrote: > From: Tony Luck > > The ACPI sysfs interface provides a way to read each ACPI table from > userspace via entries in /sys/firmware/acpi/tables/ > > The BERT table simply provides the size and address of the error > record in BIOS reserved memory and users may want access to this > record. > > In an earlier age we might have used /dev/mem to retrieve this error > record, but many systems disable /dev/mem for security reasons. > > Extend this driver to provide read-only access to the data via a > file in a new directory /sys/firmware/acpi/tables/data/BERT Should this not also have a capability check. Assuming file permissions are sufficient for grabbing a chunk of system memory holding error info doesn't seem too scary but it's at odds with a lot of other cases ? Alan