[PATCH 1/1] efi_loader: stop watchdogs in ExitBootServices()

[Heinrich Schuchardt]

On 11/9/21 18:55, Tom Rini wrote:
> On Tue, Nov 09, 2021 at 11:19:01AM +0100, Heinrich Schuchardt wrote:
> 
>> The UEFI specification requires for ExitBootServices() that "the boot
>> services watchdog timer is disabled". We already disable the software
>> watchdog. We should additionally disable the hardware watchdogs.
>>
>> Reported-by: Andre Przywara <andre.przywara at arm.com>
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> 
> Let me start by saying thank you for bringing this up with UEFI folks as
> well.  To be clear, for right now I would much rather see U-Boot
> continue to be non-complaint with UEFI in this regard and assume that a
> running watchdog will be able to be handled by the running OS (which
> tends to be the case, but not always as sunxi has just shown) than to
> attempt to be complaint with the spec as it stands now as I am hopeful
> that we can get this case handled in a way that matches long standing
> industry practice.
> 

We have either merge this patch or

[1/1] watchdog: don't autostart watchdog on Sunxi boards
https://patchwork.ozlabs.org/project/uboot/patch/20211105183431.117221-1-heinrich.schuchardt@canonical.com/

or we will be breaking boot processes that have been running up to now.

As Sunxi watchdogs were only enabled by a recent patch disabling 
autostart should not cause any harm.

If you want to be able to deviate from the UEFI spec, this should be 
customizable and disabled by default.

Best regards

Heinrich