[PATCH 2/4] powerpc/xive: fix hcall H_INT_RESET to support long busy delays

[Cédric Le Goater]

On 05/04/2018 12:41 PM, Michael Ellerman wrote:
> Cédric Le Goater <clg at kaod.org> writes:
> 
>> diff --git a/arch/powerpc/sysdev/xive/spapr.c b/arch/powerpc/sysdev/xive/spapr.c
>> index 091f1d0d0af1..7113f5d87952 100644
>> --- a/arch/powerpc/sysdev/xive/spapr.c
>> +++ b/arch/powerpc/sysdev/xive/spapr.c
>> @@ -108,6 +109,52 @@ static void xive_irq_bitmap_free(int irq)
>>  	}
>>  }
>>  
>> +
>> +/* Based on the similar routines in RTAS */
>> +static unsigned int plpar_busy_delay_time(long rc)
>> +{
>> +	unsigned int ms = 0;
>> +
>> +	if (H_IS_LONG_BUSY(rc)) {
>> +		ms = get_longbusy_msecs(rc);
>> +	} else if (rc == H_BUSY) {
>> +		ms = 10; /* seems appropriate for XIVE hcalls */
>> +	}
>> +
>> +	return ms;
>> +}
>> +
>> +static unsigned int plpar_busy_delay(int rc)
>> +{
>> +	unsigned int ms;
>> +
>> +	might_sleep();
>> +	ms = plpar_busy_delay_time(rc);
>> +	if (ms && need_resched())
>> +		msleep(ms);
> 
> This is called from kexec shutdown isn't it?
> 
> In which case I don't think msleep() is a great idea.>> We could be crashing for example.

yes.

> An mdelay would be safer I think?

I agree but we would mdelay be OK ? The hcall can take up to 160ms.

Thanks,

C.