[PATCH v4] powerpc/pseries: Avoid using addr_to_pfn in real mode

[Michael Ellerman]

Ganesh <ganeshgr at linux.ibm.com> writes:
> On 7/24/20 12:09 PM, Ganesh Goudar wrote:
>
>> When an UE or memory error exception is encountered the MCE handler
>> tries to find the pfn using addr_to_pfn() which takes effective
>> address as an argument, later pfn is used to poison the page where
>> memory error occurred, recent rework in this area made addr_to_pfn
>> to run in real mode, which can be fatal as it may try to access
>> memory outside RMO region.
>>
>> Have two helper functions to separate things to be done in real mode
>> and virtual mode without changing any functionality. This also fixes
>> the following error as the use of addr_to_pfn is now moved to virtual
>> mode.
>>
>> Without this change following kernel crash is seen on hitting UE.
...
>>   
>
> We need this fix as well to fix pseries mce handling, Any comments on this patch.

Looks OK. I'll pick it up.

cheers