Some platform devices like ARM SMMU are memory-mapped and populated by
ACPI/IORT.
In this case, NUMA topology of those platform devices are exported by firmware
as
well. Software might care about the numa_node of those devices in order to
achieve
NUMA locality.
This patch will show the numa_node for this kind of devices in sysfs. For those
platform devices without numa, numa_node won't be visible.
Cc: Prime Zeng <prime.z...@hisilicon.com>
Cc: Robin Murphy <robin.mur...@arm.com>
Signed-off-by: Barry Song <song.bao....@hisilicon.com>
---
-v3: rebase to 5.8-rc1; refine commit log
Documentation/ABI/testing/sysfs-bus-platform | 10 ++++++++
drivers/base/platform.c | 26 +++++++++++++++++++-
2 files changed, 35 insertions(+), 1 deletion(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-platform
b/Documentation/ABI/testing/sysfs-bus-platform
index 5172a6124b27..194ca700e962 100644
--- a/Documentation/ABI/testing/sysfs-bus-platform
+++ b/Documentation/ABI/testing/sysfs-bus-platform
@@ -18,3 +18,13 @@ Description:
devices to opt-out of driver binding using a driver_override
name such as "none". Only a single driver may be specified in
the override, there is no support for parsing delimiters.
+
+What: /sys/bus/platform/devices/.../numa_node
+Date: June 2020
+Contact: Barry Song <song.bao....@hisilicon.com>
+Description:
+ This file contains the NUMA node to which the platform device
+ is attached. It won't be visible if the node is unknown. The
+ value comes from an ACPI _PXM method or a similar firmware
+ source. Initial users for this file would be devices like
+ arm smmu which are populated by arm64 acpi_iort.
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index c0d0a5490ac6..4369dfd57815 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -1076,13 +1076,37 @@ static ssize_t driver_override_show(struct device *dev,
}
static DEVICE_ATTR_RW(driver_override);
+static ssize_t numa_node_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", dev_to_node(dev));
+}
+static DEVICE_ATTR_RO(numa_node);
+
+static umode_t platform_dev_attrs_visible(struct kobject *kobj, struct
attribute *a,
+ int n)
+{
+ struct device *dev = container_of(kobj, typeof(*dev), kobj);
+
+ if (a == &dev_attr_numa_node.attr &&
+ dev_to_node(dev) == NUMA_NO_NODE)
+ return 0;
+
+ return a->mode;
+}
static struct attribute *platform_dev_attrs[] = {
&dev_attr_modalias.attr,
+ &dev_attr_numa_node.attr,
&dev_attr_driver_override.attr,
NULL,
};
-ATTRIBUTE_GROUPS(platform_dev);
+
+static struct attribute_group platform_dev_group = {
+ .attrs = platform_dev_attrs,
+ .is_visible = platform_dev_attrs_visible,
+};
+__ATTRIBUTE_GROUPS(platform_dev);
static int platform_uevent(struct device *dev, struct kobj_uevent_env *env)
{
--
2.23.0
