[v3 4/7] powerpc/mce: Handle UE event for memcpy_mcsafe

[Mahesh Jagannath Salgaonkar]

On 7/6/19 3:23 PM, Nicholas Piggin wrote:
> Santosh Sivaraj's on July 6, 2019 7:26 am:
>> If we take a UE on one of the instructions with a fixup entry, set nip
>> to continue exucution at the fixup entry. Stop processing the event
>> further or print it.
> 
> Minor nit, but can you instead a field in the mce data structure that
> describes the property of the event, and then the code that intends to
> ignore such events can test for it (with an appropriate comment).
> 
> So it would be has_fixup_handler or similar. Then queue_event can have
> the logic
> 
> /*
>  * Don't report this machine check because the caller has a fixup 
>  * handler which will do the appropriate error handling and reporting.
>  */
> 
> 
>> @@ -565,9 +567,18 @@ static int mce_handle_derror(struct pt_regs *regs,
>>  	return 0;
>>  }
>>  
>> -static long mce_handle_ue_error(struct pt_regs *regs)
>> +static long mce_handle_ue_error(struct pt_regs *regs,
>> +				struct mce_error_info *mce_err)
>>  {
>>  	long handled = 0;
>> +	const struct exception_table_entry *entry;
>> +
>> +	entry = search_exception_tables(regs->nip);
> 
> Uh oh, this searches module exception tables too... we can't do that
> in real mode, can we?

Yeah, we can not do that in real mode.  Should we directly call
search_extable() for kernel exception table ?

> 
> Thanks,
> Nick
>