Add details of the new hv-gpci interface file called
"processor_bus_topology" in the ABI documentation.
Signed-off-by: Kajol Jain <kj...@linux.ibm.com>
---
.../sysfs-bus-event_source-devices-hv_gpci | 29 +++++++++++++++++++
1 file changed, 29 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 12e2bf92783f..6d633167268e 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-hv_gpci
@@ -80,3 +80,32 @@ 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.
+
+What: /sys/devices/hv_gpci/interface/processor_bus_topology
+Date: June 2023
+Contact: Linux on PowerPC Developer List <linuxppc-dev@lists.ozlabs.org>
+Description: admin read only
+ This sysfs file exposes the system topology information by
making HCALL
+ H_GET_PERF_COUNTER_INFO. The HCALL is made with counter request
value
+ PROCESSOR_BUS_TOPOLOGY(0xD0).
+ * This sysfs file is only be created for power10 and above
platforms.
+ * User need root access to read data from this sysfs file.
+ * Incase the HCALL fails with hardware/permission issue, or the
support for
+ PROCESSOR_BUS_TOPOLOGY counter request value removed, this
sysfs file still be
+ created and give error when reading it.
+ * The end user reading this sysfs file need to decode sysfs
file data as per
+ underneath platform/firmware.
+
+ Possible error codes while reading this sysfs file:
+
+ * "-EPERM" : Partition is not permitted to retrieve performance
information,
+ required to set "Enable Performance Information
Collection" option.
+
+ * "-EOPNOTSUPP" : Requested system information is not available
for the firmware
+ level and platform.
+
+ * "-EIO" : Can't retrieve system information because of invalid
buffer length/invalid address
+ or because of some hardware error. Refer
getPerfCountInfo documentation for
+ more information.
+
+ * "-EFBIG" : System information exceeds PAGE_SIZE.
--
2.35.3
