Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756898Ab2JQNJi (ORCPT ); Wed, 17 Oct 2012 09:09:38 -0400 Received: from mail.skyhub.de ([78.46.96.112]:43676 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755963Ab2JQNJg (ORCPT ); Wed, 17 Oct 2012 09:09:36 -0400 Date: Wed, 17 Oct 2012 15:09:34 +0200 From: Borislav Petkov To: "Naveen N. Rao" Cc: tony.luck@intel.com, gong.chen@linux.intel.com, ananth@in.ibm.com, masbock@linux.vnet.ibm.com, x86@kernel.org, linux-kernel@vger.kernel.org, bp@amd64.org, lcm@us.ibm.com, andi@firstfloor.org, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, gregkh@suse.de, linux-edac@vger.kernel.org Subject: Re: [PATCH v3] x86/mce: Honour bios-set CMCI threshold Message-ID: <20121017130934.GB14590@x1.osrc.amd.com> Mail-Followup-To: Borislav Petkov , "Naveen N. Rao" , tony.luck@intel.com, gong.chen@linux.intel.com, ananth@in.ibm.com, masbock@linux.vnet.ibm.com, x86@kernel.org, linux-kernel@vger.kernel.org, bp@amd64.org, lcm@us.ibm.com, andi@firstfloor.org, hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, gregkh@suse.de, linux-edac@vger.kernel.org References: <20120912122516.3825.87838.stgit@localhost.localdomain> <505C51D8.6070402@linux.vnet.ibm.com> <20121017105940.GA14590@x1.osrc.amd.com> <507E9622.6090606@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <507E9622.6090606@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1333 Lines: 34 On Wed, Oct 17, 2012 at 04:57:30PM +0530, Naveen N. Rao wrote: > On 10/17/2012 04:29 PM, Borislav Petkov wrote: > >>> > >>>+static struct dev_ext_attribute dev_attr_bios_cmci_threshold = { > >>>+ __ATTR(bios_cmci_threshold, 0444, device_show_int, NULL), > >>>+ &mce_bios_cmci_threshold > > > >Ok, I just noticed this (we must've missed it during review) but why is > >this read-only? If it has to be read-only, why do we have a node for > >this in sysfs instead of simply issuing the printk statements below and > >people who are interested in this, can grep dmesg? > > This was added so that user-space tools could find out if we're > using thresholds for CMCI. That I figured out. What I can't figure out is why userspace tools need to know that - the fact that some MCI_CTL2 has a 0 CMCI threshold because BIOS forgot to set it correctly? IOW, this is a rather evolved workaround for b0rked BIOS (the gazillionth BIOS f*ckup, btw if someone is counting :)) and, on top of that, we have a read-only, special sysfs node which is pretty useless to me. Why? -- Regards/Gruss, Boris. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/