[PATCH] powerpc/pseries: Fix scv instruction crash with kexec

[Michael Ellerman]

Sourabh Jain <sourabhjain at linux.ibm.com> writes:
> On 26/06/24 14:57, Michael Ellerman wrote:
>> Nicholas Piggin <npiggin at gmail.com> writes:
>>> kexec on pseries disables AIL (reloc_on_exc), required for scv
>>> instruction support, before other CPUs have been shut down. This means
>>> they can execute scv instructions after AIL is disabled, which causes an
>>> interrupt at an unexpected entry location that crashes the kernel.
>>>
>>> Change the kexec sequence to disable AIL after other CPUs have been
>>> brought down.
>>>
>>> As a refresher, the real-mode scv interrupt vector is 0x17000, and the
>>> fixed-location head code probably couldn't easily deal with implementing
>>> such high addresses so it was just decided not to support that interrupt
>>> at all.
>>>
>>> Reported-by: Sourabh Jain <sourabhjain at linux.ibm.com>
>>   
>> Was this reported publicly? I don't remember it.
>
> No, I didn't report this issue publicly.

OK. It's always nice to have a public report so if someone else hits it,
either at the same time, or in the future, they can search the archive
and see that it's been reported.

But this now counts as a public report, so I'll just point the link at
this thread :)

cheers