Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757976AbaDKNO6 (ORCPT ); Fri, 11 Apr 2014 09:14:58 -0400 Received: from mail.skyhub.de ([78.46.96.112]:38561 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757475AbaDKNOv (ORCPT ); Fri, 11 Apr 2014 09:14:51 -0400 Date: Fri, 11 Apr 2014 15:14:42 +0200 From: Borislav Petkov To: Michal Simek Cc: Punnaiah Choudary , Rob Herring , Punnaiah Choudary Kalluri , Doug Thompson , "devicetree@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , linux-edac@vger.kernel.org, Michal Simek , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Rob Landley , punnaiah choudary kalluri , punnaiah choudary kalluri , Russell King Subject: Re: [RFC PATCH] edac: add support for ARM PL310 L2 cache parity Message-ID: <20140411131442.GA11636@pd.tnic> References: <1393770760-32550-1-git-send-email-punnaia@xilinx.com> <20140409113246.GA8778@pd.tnic> <20140409151932.GK6529@pd.tnic> <20140409174701.GO6529@pd.tnic> <53463641.1030800@monstr.eu> <20140410090246.GC29093@pd.tnic> <53466DBF.7030606@monstr.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <53466DBF.7030606@monstr.eu> 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 On Thu, Apr 10, 2014 at 12:09:03PM +0200, Michal Simek wrote: > The question here is. This driver is just reporting problem through > edac interface which is counting that errors and provide an unified > way how to report problems. Yes, normally you can use edac for reporting and error counting. But, if, as I said earlier, it is easier to solve your issue of having two entities touch one hardware and synchronizing around it is too much, just for this one case, you can simply report the errors with simple printk, without the edac interface. This is why I was asking the practical question of why do you even need the edac interface? If it is only for reporting, use printk and solve the problem of having two drivers. > Maybe as you said we don't need to use edac interface at all but by > design because every error means that there is the problem and error > should be reported and system should be reset because we just don't > know where the problem is. We know that we have a problem. > > The question also is if we should execute any code because the problem > can be with instructions and system should just reset. > > Isn't there any security issue that even executing any code is a > problem? Well, this is up to you to answer. If an UE (Uncorrectable Error) causes data to get corrupted on your system, which, as a result, corrupts visible state which lands on storage, you definitely want to stop executing any code. x86 deals very rigorously with errors like those by running an exception handler, on AMD there's also this thing called syncflood which stops any execution and a warm reset happens. So you have to think hard what those UEs cause on your systems and only then act accordingly. If something bad like the above happens, the last thing you want to do is report them to dmesg. HTH. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- 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/