Re: [PATCH v2 02/10] docs: ABI: sysfs-bus-event_source-devices-hv_gpci: Document processor_bus_topology sysfs interface file

From: kajoljain
Date: Fri Jul 14 2023 - 03:02:29 EST












Thanks Randy for the review comments, I will do these updates
for all documentation patches in my next version of patchset.

Thanks,
Kajol Jain

On 7/12/23 02:22, Randy Dunlap wrote:
> Hi--
>
> On 7/10/23 02:27, Kajol Jain wrote:
>> Add details of the new hv-gpci interface file called
>> "processor_bus_topology" in the ABI documentation.
>>
>> Signed-off-by: Kajol Jain <kjain@xxxxxxxxxxxxx>
>> ---
>> .../sysfs-bus-event_source-devices-hv_gpci | 32 +++++++++++++++++++
>> 1 file changed, 32 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..2eeeab9a20fa 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 +80,35 @@ Contact: Linux on PowerPC Developer List <linuxppc-dev@xxxxxxxxxxxxxxxx>
>> 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: July 2023
>> +Contact: Linux on PowerPC Developer List <linuxppc-dev@xxxxxxxxxxxxxxxx>
>> +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 will be created only for power10 and above platforms.
>> +
>> + * User needs root privileges to read data from this sysfs file.
>> +
>> + * This sysfs file will be created, only when the HCALL returns "H_SUCESS",
>
> H_SUCCESS
>
>> + "H_AUTHORITY" and "H_PARAMETER" as the return type.
>
> s/and/or/
>
>> +
>> + HCALL with return error type "H_AUTHORITY", can be resolved during
>
> Drop the comma ^
>
>> + runtime by setting "Enable Performance Information Collection" option.
>> +
>> + * The end user reading this sysfs file must decode the content as per
>> + underlying 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.
>> +
>> + * "-EIO" : Can't retrieve system information because of invalid buffer length/invalid address
>> + or because of some hardware error. Refer getPerfCountInfo documentation for
>
> Refer to
>
>> + more information.
>> +
>> + * "-EFBIG" : System information exceeds PAGE_SIZE.
>