From 09b791d95559ef82542063333ecaa2ac9d57118e Mon Sep 17 00:00:00 2001
From: Kajol Jain <kjain@linux.ibm.com>
Date: Sat, 3 Oct 2020 13:19:43 +0530
Subject: [PATCH] powerpc/hv-gpci: Add sysfs files inside hv-gpci device to
show cpumask
References: bsc#1177075 ltc#186099 jsc#SLE-13661
Patch-mainline: v5.10-rc1
Git-commit: 09b791d95559ef82542063333ecaa2ac9d57118e
Patch here adds a cpumask attr to hv_gpci pmu along with ABI documentation.
Primary use to expose the cpumask is for the perf tool which has the
capability to parse the driver sysfs folder and understand the
cpumask file. Having cpumask file will reduce the number of perf command
line parameters (will avoid "-C" option in the perf tool
command line). It can also notify the user which is
the current cpu used to retrieve the counter data.
command:# cat /sys/devices/hv_gpci/cpumask
0
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201003074943.338618-5-kjain@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
.../sysfs-bus-event_source-devices-hv_gpci | 7 +++++++
arch/powerpc/perf/hv-gpci.c | 18 ++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
index ed989869d116..6a023b42486c 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -72,3 +72,10 @@ Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
Description:
A number indicating the latest version of the gpci interface
that the kernel is aware of.
+
+What: /sys/devices/hv_gpci/cpumask
+Date: October 2020
+Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description: read only
+ This sysfs file exposes the cpumask which is designated to make
+ HCALLs to retrieve hv-gpci pmu event counter data.
diff --git a/arch/powerpc/perf/hv-gpci.c b/arch/powerpc/perf/hv-gpci.c
index 1bca0c1a6cfe..d48413e28c39 100644
--- a/arch/powerpc/perf/hv-gpci.c
+++ b/arch/powerpc/perf/hv-gpci.c
@@ -96,7 +96,15 @@ static ssize_t kernel_version_show(struct device *dev,
return sprintf(page, "0x%x\n", COUNTER_INFO_VERSION_CURRENT);
}
+static ssize_t cpumask_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return cpumap_print_to_pagebuf(true, buf, &hv_gpci_cpumask);
+}
+
static DEVICE_ATTR_RO(kernel_version);
+static DEVICE_ATTR_RO(cpumask);
+
HV_CAPS_ATTR(version, "0x%x\n");
HV_CAPS_ATTR(ga, "%d\n");
HV_CAPS_ATTR(expanded, "%d\n");
@@ -113,6 +121,15 @@ static struct attribute *interface_attrs[] = {
NULL,
};
+static struct attribute *cpumask_attrs[] = {
+ &dev_attr_cpumask.attr,
+ NULL,
+};
+
+static struct attribute_group cpumask_attr_group = {
+ .attrs = cpumask_attrs,
+};
+
static struct attribute_group interface_group = {
.name = "interface",
.attrs = interface_attrs,
@@ -122,6 +139,7 @@ static const struct attribute_group *attr_groups[] = {
&format_group,
&event_group,
&interface_group,
+ &cpumask_attr_group,
NULL,
};
--
2.28.0