[RFC PATCH 8/9] powerpc: Support to replay PMIs

[Madhavan Srinivasan]

On Tuesday 26 July 2016 11:20 AM, Nicholas Piggin wrote:
> On Mon, 25 Jul 2016 20:22:21 +0530
> Madhavan Srinivasan <maddy at linux.vnet.ibm.com> wrote:
>
>> Code to replay the Performance Monitoring Interrupts(PMI).
>> In the masked_interrupt handler, for PMIs we reset the MSR[EE]
>> and return. This is due the fact that PMIs are level triggered.
>> In the __check_irq_replay(), we enabled the MSR[EE] which will
>> fire the interrupt for us.
>>
>> Patch also adds a new arch_local_irq_disable_var() variant. New
>> variant takes an input value to write to the paca->soft_enabled.
>> This will be used in following patch to implement the tri-state
>> value for soft-enabled.
> Same comment also applies about patches being standalone
> transformations that work before and after. Some of these
> can be squashed together I think.
Sure.

>
>
>> Signed-off-by: Madhavan Srinivasan <maddy at linux.vnet.ibm.com>
>> ---
>>   arch/powerpc/include/asm/hw_irq.h | 14 ++++++++++++++
>>   arch/powerpc/kernel/irq.c         |  9 ++++++++-
>>   2 files changed, 22 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/include/asm/hw_irq.h
>> b/arch/powerpc/include/asm/hw_irq.h index cc69dde6eb84..863179654452
>> 100644 --- a/arch/powerpc/include/asm/hw_irq.h
>> +++ b/arch/powerpc/include/asm/hw_irq.h
>> @@ -81,6 +81,20 @@ static inline unsigned long
>> arch_local_irq_disable(void) return flags;
>>   }
>>   
>> +static inline unsigned long arch_local_irq_disable_var(int value)
>> +{
>> +	unsigned long flags, zero;
>> +
>> +	asm volatile(
>> +		"li %1,%3; lbz %0,%2(13); stb %1,%2(13)"
>> +		: "=r" (flags), "=&r" (zero)
>> +		: "i" (offsetof(struct paca_struct, soft_enabled)),\
>> +		  "i" (value)
>> +		: "memory");
>> +
>> +	return flags;
>> +}
> arch_ function suggests it is arch implementation of a generic
> kernel function or something. I think our soft interrupt levels
> are just used in powerpc specific code.
>
> The name could also be a little more descriptive.
>
> I would have our internal function be something like
>
> soft_irq_set_level(), and then the arch disable just sets to
> the appropriate level as it does today.
>
> The PMU disable level could be implemented in powerpc specific
> header with local_irq_and_pmu_disable() or something like that.

Yes. will do.

>
> Thanks,
> Nick
>