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* [PATCH 1/2] perf/smmuv3: Validate group size
@ 2019-07-31 13:37 Robin Murphy
  2019-07-31 13:37 ` [PATCH 2/2] perf/smmuv3: Validate groups for global filtering Robin Murphy
  2019-08-01 11:32 ` [PATCH 1/2] perf/smmuv3: Validate group size Will Deacon
  0 siblings, 2 replies; 6+ messages in thread
From: Robin Murphy @ 2019-07-31 13:37 UTC (permalink / raw)
  To: will, mark.rutland; +Cc: linux-arm-kernel, shameerali.kolothum.thodi

Ensure that a group will actually fit into the available counters.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/perf/arm_smmuv3_pmu.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
index da71c741cb46..dd40df2ac895 100644
--- a/drivers/perf/arm_smmuv3_pmu.c
+++ b/drivers/perf/arm_smmuv3_pmu.c
@@ -323,6 +323,7 @@ static int smmu_pmu_event_init(struct perf_event *event)
 	struct smmu_pmu *smmu_pmu = to_smmu_pmu(event->pmu);
 	struct device *dev = smmu_pmu->dev;
 	struct perf_event *sibling;
+	int group_num_events = 1;
 	u16 event_id;
 
 	if (event->attr.type != event->pmu->type)
@@ -359,6 +360,9 @@ static int smmu_pmu_event_init(struct perf_event *event)
 			dev_dbg(dev, "Can't create mixed PMU group\n");
 			return -EINVAL;
 		}
+
+		if (++group_num_events >= smmu_pmu->num_counters)
+			return -EINVAL;
 	}
 
 	hwc->idx = -1;
-- 
2.21.0.dirty


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^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH 2/2] perf/smmuv3: Validate groups for global filtering
  2019-07-31 13:37 [PATCH 1/2] perf/smmuv3: Validate group size Robin Murphy
@ 2019-07-31 13:37 ` Robin Murphy
  2019-08-01 10:56   ` Will Deacon
  2019-08-01 11:32 ` [PATCH 1/2] perf/smmuv3: Validate group size Will Deacon
  1 sibling, 1 reply; 6+ messages in thread
From: Robin Murphy @ 2019-07-31 13:37 UTC (permalink / raw)
  To: will, mark.rutland; +Cc: linux-arm-kernel, shameerali.kolothum.thodi

With global filtering, it becomes possible for users to construct
self-contradictory groups with conflicting filters. Make sure we
cover that when initially validating events.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/perf/arm_smmuv3_pmu.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
index dd40df2ac895..e1e41d2fea94 100644
--- a/drivers/perf/arm_smmuv3_pmu.c
+++ b/drivers/perf/arm_smmuv3_pmu.c
@@ -324,6 +324,8 @@ static int smmu_pmu_event_init(struct perf_event *event)
 	struct device *dev = smmu_pmu->dev;
 	struct perf_event *sibling;
 	int group_num_events = 1;
+	bool has_filter;
+	u32 filter_span, filter_sid;
 	u16 event_id;
 
 	if (event->attr.type != event->pmu->type)
@@ -354,6 +356,10 @@ static int smmu_pmu_event_init(struct perf_event *event)
 		return -EINVAL;
 	}
 
+	has_filter = get_filter_enable(event);
+	filter_span = get_filter_span(event);
+	filter_sid = get_filter_stream_id(event);
+
 	for_each_sibling_event(sibling, event->group_leader) {
 		if (sibling->pmu != event->pmu &&
 		    !is_software_event(sibling)) {
@@ -363,6 +369,16 @@ static int smmu_pmu_event_init(struct perf_event *event)
 
 		if (++group_num_events >= smmu_pmu->num_counters)
 			return -EINVAL;
+
+		if (smmu_pmu->global_filter) {
+			if (has_filter != (bool)get_filter_enable(sibling))
+				return -EINVAL;
+
+			if (has_filter &&
+			    (filter_span != get_filter_span(sibling) ||
+			    filter_sid != get_filter_stream_id (sibling)))
+				return -EINVAL;
+		}
 	}
 
 	hwc->idx = -1;
-- 
2.21.0.dirty


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^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH 2/2] perf/smmuv3: Validate groups for global filtering
  2019-07-31 13:37 ` [PATCH 2/2] perf/smmuv3: Validate groups for global filtering Robin Murphy
@ 2019-08-01 10:56   ` Will Deacon
  2019-08-01 11:17     ` Robin Murphy
  0 siblings, 1 reply; 6+ messages in thread
From: Will Deacon @ 2019-08-01 10:56 UTC (permalink / raw)
  To: Robin Murphy; +Cc: mark.rutland, linux-arm-kernel, shameerali.kolothum.thodi

On Wed, Jul 31, 2019 at 02:37:42PM +0100, Robin Murphy wrote:
> With global filtering, it becomes possible for users to construct
> self-contradictory groups with conflicting filters. Make sure we
> cover that when initially validating events.
> 
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
>  drivers/perf/arm_smmuv3_pmu.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
> index dd40df2ac895..e1e41d2fea94 100644
> --- a/drivers/perf/arm_smmuv3_pmu.c
> +++ b/drivers/perf/arm_smmuv3_pmu.c
> @@ -324,6 +324,8 @@ static int smmu_pmu_event_init(struct perf_event *event)
>  	struct device *dev = smmu_pmu->dev;
>  	struct perf_event *sibling;
>  	int group_num_events = 1;
> +	bool has_filter;
> +	u32 filter_span, filter_sid;
>  	u16 event_id;
>  
>  	if (event->attr.type != event->pmu->type)
> @@ -354,6 +356,10 @@ static int smmu_pmu_event_init(struct perf_event *event)
>  		return -EINVAL;
>  	}
>  
> +	has_filter = get_filter_enable(event);
> +	filter_span = get_filter_span(event);
> +	filter_sid = get_filter_stream_id(event);
> +
>  	for_each_sibling_event(sibling, event->group_leader) {
>  		if (sibling->pmu != event->pmu &&
>  		    !is_software_event(sibling)) {
> @@ -363,6 +369,16 @@ static int smmu_pmu_event_init(struct perf_event *event)
>  
>  		if (++group_num_events >= smmu_pmu->num_counters)
>  			return -EINVAL;
> +
> +		if (smmu_pmu->global_filter) {
> +			if (has_filter != (bool)get_filter_enable(sibling))
> +				return -EINVAL;
> +
> +			if (has_filter &&
> +			    (filter_span != get_filter_span(sibling) ||
> +			    filter_sid != get_filter_stream_id (sibling)))
> +				return -EINVAL;
> +		}

Can we avoid duplicating the validation logic from
smmu_pmu_apply_event_filter() by adding the group to a fake PMU, like we
do for the CPU PMU and the DSU PMU? You'll probably need to do a bit
of surgery on 'struct smmu_pmu' to move out the bits you need, but I
think it would be better that way.

Will

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linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 2/2] perf/smmuv3: Validate groups for global filtering
  2019-08-01 10:56   ` Will Deacon
@ 2019-08-01 11:17     ` Robin Murphy
  2019-08-01 11:45       ` Will Deacon
  0 siblings, 1 reply; 6+ messages in thread
From: Robin Murphy @ 2019-08-01 11:17 UTC (permalink / raw)
  To: Will Deacon; +Cc: mark.rutland, linux-arm-kernel, shameerali.kolothum.thodi

On 2019-08-01 11:56 am, Will Deacon wrote:
> On Wed, Jul 31, 2019 at 02:37:42PM +0100, Robin Murphy wrote:
>> With global filtering, it becomes possible for users to construct
>> self-contradictory groups with conflicting filters. Make sure we
>> cover that when initially validating events.
>>
>> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
>> ---
>>   drivers/perf/arm_smmuv3_pmu.c | 16 ++++++++++++++++
>>   1 file changed, 16 insertions(+)
>>
>> diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
>> index dd40df2ac895..e1e41d2fea94 100644
>> --- a/drivers/perf/arm_smmuv3_pmu.c
>> +++ b/drivers/perf/arm_smmuv3_pmu.c
>> @@ -324,6 +324,8 @@ static int smmu_pmu_event_init(struct perf_event *event)
>>   	struct device *dev = smmu_pmu->dev;
>>   	struct perf_event *sibling;
>>   	int group_num_events = 1;
>> +	bool has_filter;
>> +	u32 filter_span, filter_sid;
>>   	u16 event_id;
>>   
>>   	if (event->attr.type != event->pmu->type)
>> @@ -354,6 +356,10 @@ static int smmu_pmu_event_init(struct perf_event *event)
>>   		return -EINVAL;
>>   	}
>>   
>> +	has_filter = get_filter_enable(event);
>> +	filter_span = get_filter_span(event);
>> +	filter_sid = get_filter_stream_id(event);
>> +
>>   	for_each_sibling_event(sibling, event->group_leader) {
>>   		if (sibling->pmu != event->pmu &&
>>   		    !is_software_event(sibling)) {
>> @@ -363,6 +369,16 @@ static int smmu_pmu_event_init(struct perf_event *event)
>>   
>>   		if (++group_num_events >= smmu_pmu->num_counters)
>>   			return -EINVAL;
>> +
>> +		if (smmu_pmu->global_filter) {
>> +			if (has_filter != (bool)get_filter_enable(sibling))
>> +				return -EINVAL;
>> +
>> +			if (has_filter &&
>> +			    (filter_span != get_filter_span(sibling) ||
>> +			    filter_sid != get_filter_stream_id (sibling)))
>> +				return -EINVAL;
>> +		}
> 
> Can we avoid duplicating the validation logic from
> smmu_pmu_apply_event_filter() by adding the group to a fake PMU, like we
> do for the CPU PMU and the DSU PMU? You'll probably need to do a bit
> of surgery on 'struct smmu_pmu' to move out the bits you need, but I
> think it would be better that way.

Given that apply_event_filter() includes the actual register writes, I 
have a strong feeling that down that road lies madness. However, on a 
second look, I see no reason not to factor out the global filter 
validation part for reuse, and in fact I think we can even save 
explicitly tracking global_filter_{span,sid} that way. I'll give it a try.

Robin.

(and hopefully the promise of a respin will let us all overlook the 
obvious "forgot to update the condition when I changed my mind about the 
count" error in patch #1...)

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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] perf/smmuv3: Validate group size
  2019-07-31 13:37 [PATCH 1/2] perf/smmuv3: Validate group size Robin Murphy
  2019-07-31 13:37 ` [PATCH 2/2] perf/smmuv3: Validate groups for global filtering Robin Murphy
@ 2019-08-01 11:32 ` Will Deacon
  1 sibling, 0 replies; 6+ messages in thread
From: Will Deacon @ 2019-08-01 11:32 UTC (permalink / raw)
  To: Robin Murphy; +Cc: mark.rutland, linux-arm-kernel, shameerali.kolothum.thodi

On Wed, Jul 31, 2019 at 02:37:41PM +0100, Robin Murphy wrote:
> Ensure that a group will actually fit into the available counters.
> 
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
>  drivers/perf/arm_smmuv3_pmu.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
> index da71c741cb46..dd40df2ac895 100644
> --- a/drivers/perf/arm_smmuv3_pmu.c
> +++ b/drivers/perf/arm_smmuv3_pmu.c
> @@ -323,6 +323,7 @@ static int smmu_pmu_event_init(struct perf_event *event)
>  	struct smmu_pmu *smmu_pmu = to_smmu_pmu(event->pmu);
>  	struct device *dev = smmu_pmu->dev;
>  	struct perf_event *sibling;
> +	int group_num_events = 1;
>  	u16 event_id;
>  
>  	if (event->attr.type != event->pmu->type)
> @@ -359,6 +360,9 @@ static int smmu_pmu_event_init(struct perf_event *event)
>  			dev_dbg(dev, "Can't create mixed PMU group\n");
>  			return -EINVAL;
>  		}
> +
> +		if (++group_num_events >= smmu_pmu->num_counters)
> +			return -EINVAL;

Did you forget to update the condition when you changed your mind about the
count?

;)

Will

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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 2/2] perf/smmuv3: Validate groups for global filtering
  2019-08-01 11:17     ` Robin Murphy
@ 2019-08-01 11:45       ` Will Deacon
  0 siblings, 0 replies; 6+ messages in thread
From: Will Deacon @ 2019-08-01 11:45 UTC (permalink / raw)
  To: Robin Murphy; +Cc: mark.rutland, linux-arm-kernel, shameerali.kolothum.thodi

On Thu, Aug 01, 2019 at 12:17:20PM +0100, Robin Murphy wrote:
> On 2019-08-01 11:56 am, Will Deacon wrote:
> > On Wed, Jul 31, 2019 at 02:37:42PM +0100, Robin Murphy wrote:
> > > With global filtering, it becomes possible for users to construct
> > > self-contradictory groups with conflicting filters. Make sure we
> > > cover that when initially validating events.
> > > 
> > > Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> > > ---
> > >   drivers/perf/arm_smmuv3_pmu.c | 16 ++++++++++++++++
> > >   1 file changed, 16 insertions(+)
> > > 
> > > diff --git a/drivers/perf/arm_smmuv3_pmu.c b/drivers/perf/arm_smmuv3_pmu.c
> > > index dd40df2ac895..e1e41d2fea94 100644
> > > --- a/drivers/perf/arm_smmuv3_pmu.c
> > > +++ b/drivers/perf/arm_smmuv3_pmu.c
> > > @@ -324,6 +324,8 @@ static int smmu_pmu_event_init(struct perf_event *event)
> > >   	struct device *dev = smmu_pmu->dev;
> > >   	struct perf_event *sibling;
> > >   	int group_num_events = 1;
> > > +	bool has_filter;
> > > +	u32 filter_span, filter_sid;
> > >   	u16 event_id;
> > >   	if (event->attr.type != event->pmu->type)
> > > @@ -354,6 +356,10 @@ static int smmu_pmu_event_init(struct perf_event *event)
> > >   		return -EINVAL;
> > >   	}
> > > +	has_filter = get_filter_enable(event);
> > > +	filter_span = get_filter_span(event);
> > > +	filter_sid = get_filter_stream_id(event);
> > > +
> > >   	for_each_sibling_event(sibling, event->group_leader) {
> > >   		if (sibling->pmu != event->pmu &&
> > >   		    !is_software_event(sibling)) {
> > > @@ -363,6 +369,16 @@ static int smmu_pmu_event_init(struct perf_event *event)
> > >   		if (++group_num_events >= smmu_pmu->num_counters)
> > >   			return -EINVAL;
> > > +
> > > +		if (smmu_pmu->global_filter) {
> > > +			if (has_filter != (bool)get_filter_enable(sibling))
> > > +				return -EINVAL;
> > > +
> > > +			if (has_filter &&
> > > +			    (filter_span != get_filter_span(sibling) ||
> > > +			    filter_sid != get_filter_stream_id (sibling)))
> > > +				return -EINVAL;
> > > +		}
> > 
> > Can we avoid duplicating the validation logic from
> > smmu_pmu_apply_event_filter() by adding the group to a fake PMU, like we
> > do for the CPU PMU and the DSU PMU? You'll probably need to do a bit
> > of surgery on 'struct smmu_pmu' to move out the bits you need, but I
> > think it would be better that way.
> 
> Given that apply_event_filter() includes the actual register writes, I have
> a strong feeling that down that road lies madness. However, on a second
> look, I see no reason not to factor out the global filter validation part
> for reuse, and in fact I think we can even save explicitly tracking
> global_filter_{span,sid} that way. I'll give it a try.

Oh yes, performing the actual register writes could be catastrophic!
All I'm trying to get to is a situation where we don't have to update both
the event_init() and smmu_pmu_get_event_idx() callchains if we gain
additional validation requirements in future.

> (and hopefully the promise of a respin will let us all overlook the obvious
> "forgot to update the condition when I changed my mind about the count"
> error in patch #1...)

I noticed it looked weird, but assumed I was being thick and then forgot
about it.

Will

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^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2019-08-01 11:46 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-07-31 13:37 [PATCH 1/2] perf/smmuv3: Validate group size Robin Murphy
2019-07-31 13:37 ` [PATCH 2/2] perf/smmuv3: Validate groups for global filtering Robin Murphy
2019-08-01 10:56   ` Will Deacon
2019-08-01 11:17     ` Robin Murphy
2019-08-01 11:45       ` Will Deacon
2019-08-01 11:32 ` [PATCH 1/2] perf/smmuv3: Validate group size Will Deacon

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