[v3] powerpc: Handle MCE on POWER9 with only DSISR bit 33 set

Michael Ellerman patch-notifications at ellerman.id.au
Tue Sep 26 22:04:31 AEST 2017


On Fri, 2017-09-22 at 03:32:21 UTC, Michael Neuling wrote:
> On POWER9 DD2.1 and below, it's possible for a paste instruction to
> cause a Machine Check Exception (MCE) where only DSISR bit 33 is
> set. This will result in the MCE handler seeing an unknown event,
> which triggers linux to crash.
> 
> We change this by detecting unknown events caused by load/stores in
> the MCE handler and marking them as handled so that we no longer
> crash.
> 
> An MCE that occurs like this is spurious, so we don't need to do
> anything in terms of servicing it. If there is something that needs to
> be serviced, the CPU will raise the MCE again with the correct DSISR
> so that it can be serviced properly.
> 
> Signed-off-by: Michael Neuling <mikey at neuling.org>
> Reviewed-by: Nicholas Piggin <npiggin at gmail.com
> Acked-by: Balbir SIngh <bsingharora at gmail.com>

Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/d8bd9f3f0925d22726de159531bfe3

cheers


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