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From: Rob Herring <robh@kernel.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>, Al Grant <al.grant@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm_pmu: Validate single/group leader events
Date: Mon, 11 Apr 2022 09:14:03 -0500	[thread overview]
Message-ID: <YlQ3q9YFhQU9JsBt@robh.at.kernel.org> (raw)
In-Reply-To: <YlP9KgIZ1PW64tn9@FVFF77S0Q05N>

On Mon, Apr 11, 2022 at 11:04:26AM +0100, Mark Rutland wrote:
> Hi Rob,
> 
> On Fri, Apr 08, 2022 at 03:33:30PM -0500, Rob Herring wrote:
> > In the case where there is only a cycle counter available (i.e.
> > PMCR_EL0.N is 0) and an event other than CPU cycles is opened, the open
> > should fail as the event can never possibly be scheduled. However, the
> > event validation when an event is opened is skipped when the group
> > leader is opened. Fix this by always validating the group leader events.
> > 
> > Reported-by: Al Grant <al.grant@arm.com>
> > Cc: Will Deacon <will@kernel.org>
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Signed-off-by: Rob Herring <robh@kernel.org>
> 
> This looks obviously correct to me, so FWIW:
> 
> Acked-by: Mark Rutland <mark.rutland@arm.com>

Thanks.

> Just to check, have you tested this (e.g. by running on a platform with
> PMCR_EL0.N == 0, or hacking the PMU probing to report just the cycle counter)

Yes, tested on FVP with 0 counters running the libperf evsel userspace 
access tests as that tries both the cycle counter and instruction 
counts.

Rob

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WARNING: multiple messages have this Message-ID (diff)
From: Rob Herring <robh@kernel.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>, Al Grant <al.grant@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm_pmu: Validate single/group leader events
Date: Mon, 11 Apr 2022 09:14:03 -0500	[thread overview]
Message-ID: <YlQ3q9YFhQU9JsBt@robh.at.kernel.org> (raw)
In-Reply-To: <YlP9KgIZ1PW64tn9@FVFF77S0Q05N>

On Mon, Apr 11, 2022 at 11:04:26AM +0100, Mark Rutland wrote:
> Hi Rob,
> 
> On Fri, Apr 08, 2022 at 03:33:30PM -0500, Rob Herring wrote:
> > In the case where there is only a cycle counter available (i.e.
> > PMCR_EL0.N is 0) and an event other than CPU cycles is opened, the open
> > should fail as the event can never possibly be scheduled. However, the
> > event validation when an event is opened is skipped when the group
> > leader is opened. Fix this by always validating the group leader events.
> > 
> > Reported-by: Al Grant <al.grant@arm.com>
> > Cc: Will Deacon <will@kernel.org>
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Signed-off-by: Rob Herring <robh@kernel.org>
> 
> This looks obviously correct to me, so FWIW:
> 
> Acked-by: Mark Rutland <mark.rutland@arm.com>

Thanks.

> Just to check, have you tested this (e.g. by running on a platform with
> PMCR_EL0.N == 0, or hacking the PMU probing to report just the cycle counter)

Yes, tested on FVP with 0 counters running the libperf evsel userspace 
access tests as that tries both the cycle counter and instruction 
counts.

Rob

  reply	other threads:[~2022-04-11 14:15 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-08 20:33 [PATCH] arm_pmu: Validate single/group leader events Rob Herring
2022-04-08 20:33 ` Rob Herring
2022-04-11 10:04 ` Mark Rutland
2022-04-11 10:04   ` Mark Rutland
2022-04-11 14:14   ` Rob Herring [this message]
2022-04-11 14:14     ` Rob Herring
2022-04-12 10:14     ` Mark Rutland
2022-04-12 10:14       ` Mark Rutland
2022-04-13 11:46 ` Will Deacon
2022-04-13 11:46   ` Will Deacon

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