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From: "Bryan O'Donoghue" <pure.logic@nexus-software.ie>
To: "Kweh, Hock Leong" <hock.leong.kweh@intel.com>,
	Matt Fleming <matt@codeblueprint.co.uk>
Cc: "linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	joeyli <jlee@suse.com>, Borislav Petkov <bp@alien8.de>,
	"Ong, Boon Leong" <boon.leong.ong@intel.com>,
	"Ong, Kean Chai" <kean.chai.ong@intel.com>
Subject: Re: [PATCH] efi/capsule: Make efi_capsule_pending() lockless
Date: Fri, 06 May 2016 02:32:03 +0100	[thread overview]
Message-ID: <1462498323.2404.8.camel@nexus-software.ie> (raw)
In-Reply-To: <F54AEECA5E2B9541821D670476DAE19C4A914755@PGSMSX102.gar.corp.intel.com>

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

      parent reply	other threads:[~2016-05-06  1:32 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-30 22:13 [PATCH] efi/capsule: Make efi_capsule_pending() lockless Matt Fleming
2016-05-03  9:02 ` Borislav Petkov
2016-05-03 14:12   ` Matt Fleming
2016-05-04  9:30     ` Borislav Petkov
2016-05-04 11:46       ` Matt Fleming
2016-05-04 12:20         ` Borislav Petkov
2016-05-04 13:36           ` Matt Fleming
2016-05-04 14:35           ` Matt Fleming
2016-05-05 14:27             ` Kweh, Hock Leong
2016-05-05 14:36               ` Matt Fleming
2016-05-05 14:55                 ` One Thousand Gnomes
2016-05-06  1:32               ` Bryan O'Donoghue [this message]

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