From: Mark Rutland <mark.rutland@arm.com>
To: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, Will.Deacon@arm.com,
catalin.marinas@arm.com, acme@kernel.org,
alexander.shishkin@linux.intel.com, peterz@infradead.org,
mingo@redhat.com, jnair@caviumnetworks.com, gpkulkarni@gmail.com
Subject: Re: [PATCH v2] arm64: perf: Use only exclude_kernel attribute when kernel is running in HYP
Date: Thu, 20 Apr 2017 09:49:29 +0100 [thread overview]
Message-ID: <20170420084928.GC31436@leverpostej> (raw)
In-Reply-To: <1492623846-29335-1-git-send-email-ganapatrao.kulkarni@cavium.com>
On Wed, Apr 19, 2017 at 11:14:06PM +0530, Ganapatrao Kulkarni wrote:
> commit d98ecda (arm64: perf: Count EL2 events if the kernel is running in HYP)
> is returning error for perf syscall with mixed attribute set for exclude_kernel
> and exclude_hv. This change is breaking some applications (observed with hhvm)
> when ran on VHE enabled platforms.
>
> Adding fix to consider only exclude_kernel attribute when kernel is
> running in HYP. Also adding sysfs file to notify the bhehaviour
> of attribute exclude_hv.
>
> Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com>
> ---
>
> Changelog:
>
> V2:
> - Changes as per Will Deacon's suggestion.
>
> V1: Initial patch
>
> arch/arm64/kernel/perf_event.c | 28 ++++++++++++++++++++++++----
> include/linux/perf/arm_pmu.h | 1 +
> 2 files changed, 25 insertions(+), 4 deletions(-)
>
> @@ -871,14 +890,13 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event,
>
> if (attr->exclude_idle)
> return -EPERM;
> - if (is_kernel_in_hyp_mode() &&
> - attr->exclude_kernel != attr->exclude_hv)
> - return -EINVAL;
> + if (is_kernel_in_hyp_mode() && !attr->exclude_kernel)
> + config_base |= ARMV8_PMU_INCLUDE_EL2;
> if (attr->exclude_user)
> config_base |= ARMV8_PMU_EXCLUDE_EL0;
> if (!is_kernel_in_hyp_mode() && attr->exclude_kernel)
> config_base |= ARMV8_PMU_EXCLUDE_EL1;
> - if (!attr->exclude_hv)
> + if (!is_kernel_in_hyp_mode() && !attr->exclude_hv)
> config_base |= ARMV8_PMU_INCLUDE_EL2;
This isn't quite what Will suggested.
The idea was that userspace would read sysfs, then use that to determine
the correct exclusion parameters [1,2]. This logic was not expected to
change; it correctly validates whether we can provide what the user
requests.
Thanks,
Mark.
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-April/499224.html
[2] http://lists.infradead.org/pipermail/linux-arm-kernel/2017-April/499493.html
>
> /*
> @@ -1008,6 +1026,8 @@ static int armv8_pmuv3_init(struct arm_pmu *cpu_pmu)
> &armv8_pmuv3_events_attr_group;
> cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_FORMATS] =
> &armv8_pmuv3_format_attr_group;
> + cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_ATTR] =
> + &armv8_pmuv3_attr_group;
> return armv8pmu_probe_pmu(cpu_pmu);
> }
>
> diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
> index 8462da2..a26ffc7 100644
> --- a/include/linux/perf/arm_pmu.h
> +++ b/include/linux/perf/arm_pmu.h
> @@ -81,6 +81,7 @@ enum armpmu_attr_groups {
> ARMPMU_ATTR_GROUP_COMMON,
> ARMPMU_ATTR_GROUP_EVENTS,
> ARMPMU_ATTR_GROUP_FORMATS,
> + ARMPMU_ATTR_GROUP_ATTR,
> ARMPMU_NR_ATTR_GROUPS
> };
>
> --
> 1.8.1.4
>
next prev parent reply other threads:[~2017-04-20 8:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 17:44 [PATCH v2] arm64: perf: Use only exclude_kernel attribute when kernel is running in HYP Ganapatrao Kulkarni
2017-04-20 8:49 ` Mark Rutland [this message]
2017-04-20 9:26 ` Ganapatrao Kulkarni
2017-04-24 15:45 ` Will Deacon
2017-04-25 3:43 ` Ganapatrao Kulkarni
2017-04-25 16:53 ` Will Deacon
2017-04-26 6:53 ` Jayachandran C.
[not found] ` <CY4PR07MB3415C0CEBB9D3DF0C249DC6793110@CY4PR07MB3415.namprd07.prod.outlook.com>
2017-04-26 10:10 ` Will Deacon
2017-04-26 13:41 ` Jayachandran C
2017-04-27 17:37 ` Will Deacon
2017-04-28 13:46 ` Jayachandran C
2017-04-28 16:38 ` Will Deacon
2017-05-01 16:10 ` Jayachandran C
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