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From: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: benh@kernel.crashing.org, mpe@ellerman.id.au, anton@samba.org,
	paulus@samba.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v5 08/12] powerpc: Add support to mask perf interrupts and replay them
Date: Wed, 4 Jan 2017 22:21:05 +0530	[thread overview]
Message-ID: <fff30cf9-a589-2a6d-ec87-40a92fb084a2@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170104223801.739a09a7@roar.ozlabs.ibm.com>



On Wednesday 04 January 2017 06:08 PM, Nicholas Piggin wrote:
> On Wed,  4 Jan 2017 17:19:46 +0530
> Madhavan Srinivasan <maddy@linux.vnet.ibm.com> wrote:
>
>> @@ -134,7 +137,7 @@ static inline bool arch_irqs_disabled(void)
>>   	_was_enabled = local_paca->soft_enabled;	\
>>   	local_paca->soft_enabled = IRQ_DISABLE_MASK_LINUX;\
>>   	local_paca->irq_happened |= PACA_IRQ_HARD_DIS;	\
>> -	if (!(_was_enabled & IRQ_DISABLE_MASK_LINUX))	\
>> +	if (!(_was_enabled & IRQ_DISABLE_MASK_ALL))	\
>>   		trace_hardirqs_off();			\
>>   } while(0)
> Hang on, maybe there's some confusion about this. trace_hardirqs_off() is
> for Linux irqs (i.e., local_irq_disable()), so that should continue to
> test just the LINUX mask I think. Otherwise this
>
>      powerpc_local_pmu_disable();
>      hard_irq_disable();

Currently we set both bits for pmu soft disable

                 flags = 
soft_disabled_mask_or_return(IRQ_DISABLE_MASK_LINUX | \
IRQ_DISABLE_MASK_PMU);                  \

So yes in the above seq, we will miss the pmu bit. But since 
trace_hardirqs_off()
is for _LINUX, instead will it not be safer to OR it?

         local_paca->soft_disabled_mask |= IRQ_DISABLE_MASK_LINUX;\

Maddy

> Will miss calling trace_hardirqs_off(). You don't have a function that
> disables PMU irqs without Linux irqs, but one might exist.
>
> What I was concerned about is actually setting the disable mask to ALL
>
>    	local_paca->soft_enabled = IRQ_DISABLE_MASK_ALL;
>
> No? Otherwise if you did
>
>      powerpc_local_irq_pmu_disable();
>      hard_irq_disable();
>
> Then you would lose the PMU bit out of the mask.
>
> Thanks,
> Nick
>

  reply	other threads:[~2017-01-04 16:51 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-04 11:49 [PATCH v5 00/12]powerpc: "paca->soft_enabled" based local atomic operation implementation Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 01/12] powerpc: Add #defs for paca->soft_enabled flags Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 02/12] powerpc: move set_soft_enabled() and rename Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 03/12] powerpc: Use soft_enabled_set api to update paca->soft_enabled Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 04/12] powerpc: Add soft_enabled manipulation functions Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 05/12] powerpc: reverse the soft_enable logic Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 06/12] powerpc: Avoid using EXCEPTION_PROLOG_1 macro in MASKABLE_* Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 07/12] Add support to take additional parameter in MASKABLE_* macro Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 08/12] powerpc: Add support to mask perf interrupts and replay them Madhavan Srinivasan
2017-01-04 12:38   ` Nicholas Piggin
2017-01-04 16:51     ` Madhavan Srinivasan [this message]
2017-01-05  6:05       ` Nicholas Piggin
2017-01-04 11:49 ` [PATCH v5 09/12] powerpc:Add new kconfig IRQ_DEBUG_SUPPORT Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 10/12] powerpc: Add new set of soft_enabled_ functions Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 11/12] powerpc: rewrite local_t using soft_irq Madhavan Srinivasan
2017-01-04 11:49 ` [PATCH v5 12/12] powerpc: Rename soft_enabled to soft_disabled_mask Madhavan Srinivasan

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