lkml.org 
[lkml]   [2017]   [Apr]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2] arm64: perf: Use only exclude_kernel attribute when kernel is running in HYP
Date
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(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 57ae9d9..b35b94c 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -535,6 +535,25 @@
.attrs = armv8_pmuv3_format_attrs,
};

+static ssize_t armv8_pmuv3_exclude_hv_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", is_kernel_in_hyp_mode() ? 1 : 0);
+}
+
+static struct device_attribute armv8_pmuv3_exclude_hv_attr =
+ __ATTR(exclude_hv, 0444, armv8_pmuv3_exclude_hv_show, NULL);
+
+static struct attribute *armv8_pmuv3_attrs[] = {
+ &armv8_pmuv3_exclude_hv_attr.attr,
+ NULL,
+};
+
+static struct attribute_group armv8_pmuv3_attr_group = {
+ .name = "attr",
+ .attrs = armv8_pmuv3_attrs,
+};
+
/*
* Perf Events' indices
*/
@@ -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;

/*
@@ -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
\
 
 \ /
  Last update: 2017-04-19 19:46    [W:2.584 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site