From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756240AbcEFBcL (ORCPT ); Thu, 5 May 2016 21:32:11 -0400 Received: from mail-wm0-f47.google.com ([74.125.82.47]:36448 "EHLO mail-wm0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753786AbcEFBcI (ORCPT ); Thu, 5 May 2016 21:32:08 -0400 Message-ID: <1462498323.2404.8.camel@nexus-software.ie> Subject: Re: [PATCH] efi/capsule: Make efi_capsule_pending() lockless From: "Bryan O'Donoghue" To: "Kweh, Hock Leong" , Matt Fleming Cc: "linux-efi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Ard Biesheuvel , joeyli , Borislav Petkov , "Ong, Boon Leong" , "Ong, Kean Chai" Date: Fri, 06 May 2016 02:32:03 +0100 In-Reply-To: References: <1462054407-9735-1-git-send-email-matt@codeblueprint.co.uk> <20160503090229.GC27540@pd.tnic> <20160503141201.GW2839@codeblueprint.co.uk> <20160504093031.GA4074@pd.tnic> <20160504114605.GH2839@codeblueprint.co.uk> <20160504122042.GB4074@pd.tnic> <20160504143531.GK2839@codeblueprint.co.uk> Organization: Nexus Software Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.5-1ubuntu3.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2016-05-05 at 14:27 +0000, Kweh, Hock Leong wrote: > > -----Original Message----- > > From: Matt Fleming [mailto:matt@codeblueprint.co.uk] > > Sent: Wednesday, May 04, 2016 10:36 PM > > To: Kweh, Hock Leong; Bryan O'Donoghue > > Cc: linux-efi@vger.kernel.org; linux-kernel@vger.kernel.org; Ard > > Biesheuvel; > > joeyli; Borislav Petkov > > Subject: Re: [PATCH] efi/capsule: Make efi_capsule_pending() > > lockless > > > > On Wed, 04 May, at 02:20:42PM, Borislav Petkov wrote: > > > > > > Blergh. > > > > Wilson, Bryan, what kind of rollback support does the Intel Quark > > have if its > > firmware update is interrupted? > > > > The interruption could be for a number of reasons including power > > loss, or > > the example in this case, rebooting due to panic(). > > If not mistaken, the EFI firmware will not update a partially > uploaded binary due to checksum error. > User is required to re-update the efi capsule again on the next boot > up. > If the checksum fails then you're fine since you won't update flash. OTOH if you pull the plug we actually have a backup image - so even a partially flashed update shouldn't brick the system. How well that actually works i.e. is it tested in anger ? Meh - YMMV there fore sure. --- bod