Re: [PATCH 1/3] arm64: Use FEAT_HAFDBS to track dirty pages when available

[Marc Zyngier <maz@kernel.org>]

On 2023-10-13 03:40, Chris Packham wrote:
> Hi Marc, Paul,
> 
> On Sat, Mar 18, 2023 at 5:23 AM Ying-Chun Liu (PaulLiu)
> <paul.liu@linaro.org> wrote:
>> 
>> From: Marc Zyngier <maz@kernel.org>
>> 
>> Some recent arm64 cores have a facility that allows the page
>> table walker to track the dirty state of a page. This makes it
>> really efficient to perform CMOs by VA as we only need to look
>> at dirty pages.
>> 
>> Signed-off-by: Marc Zyngier <maz@kernel.org>
>> [ Paul: pick from the Android tree. Rebase to the upstream ]
>> Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
>> Cc: Tom Rini <trini@konsulko.com>
>> Link: 
>> https://android.googlesource.com/platform/external/u-boot/+/3c433724e6f830a6b2edd5ec3d4a504794887263
> 
> I think this may have caused a regression for the Marvell AC5X
> board(s). I found that v2023.07 locked up at boot but v2023.01 was
> fine. The lockup seemed to be in the 'Net:' init probably just as the
> mvneta driver was being initialised.
> 
> A git bisect led me to this change although for this specific change
> instead of the lockup I get a crash so maybe I'm actually hitting a
> different issue.
> 
> Any thoughts as to why this may have caused problems?

Not really. What CPUs does this platform have? What is the offending
driver doing to trigger the issue? Can you provide some level of
tracing?

         M.
-- 
Jazz is not dead. It just smells funny...