[PATCH v3 4/4] Documentation/powerpc/fadump: add additional parameter feature details

[Sourabh Jain]

Hello Mahesh,


On 26/01/25 17:31, Mahesh J Salgaonkar wrote:
> On 2025-01-23 17:12:54 Thu, Sourabh Jain wrote:
>> Update the fadump document to include details about the fadump
>> additional parameter feature.
>>
>> The document includes the following:
>> - Significance of the feature
>> - How to use it
>> - Feature restrictions
>>
>> No functional changes are introduced.
>>
>> Cc: Avnish Chouhan <avnish at linux.ibm.com>
>> Cc: Brian King <brking at linux.ibm.com>
>> Cc: Hari Bathini <hbathini at linux.ibm.com>
>> Cc: Madhavan Srinivasan <maddy at linux.ibm.com>
>> Cc: Michael Ellerman <mpe at ellerman.id.au>
>> Cc: Mahesh Salgaonkar <mahesh at linux.ibm.com>
>> Signed-off-by: Sourabh Jain <sourabhjain at linux.ibm.com>
>> ---
>>   Documentation/ABI/testing/sysfs-kernel-fadump |  3 ++-
>>   .../arch/powerpc/firmware-assisted-dump.rst   | 22 +++++++++++++++++++
>>   2 files changed, 24 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump
>> index 2f9daa7ca55b..b64b7622e6fc 100644
>> --- a/Documentation/ABI/testing/sysfs-kernel-fadump
>> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
> [...]
>> +-- Support for Additional Kernel Arguments in Fadump
>> +   Fadump has a feature that allows passing additional kernel arguments
>> +   to the fadump kernel. This feature was primarily designed to disable
>> +   kernel functionalities that are not required for the fadump kernel
>> +   and to reduce its memory footprint while collecting the dump.
>> +
>> +  Command to Add Additional Kernel Parameters to Fadump:
>> +  e.g.
>> +  # echo "nr_cpus=16" > /sys/kernel/fadump/bootargs_append
>> +
>> +  The above command is sufficient to add additional arguments to fadump.
>> +  An explicit service restart is not required.
>> +
>> +  Command to Retrieve the Additional Fadump Arguments:
>> +  e.g.
>> +  # cat /sys/kernel/fadump/bootargs_append
>> +
>> +Note: Additional kernel arguments for fadump with HASH MMU is only
>> +      supported if the RMA size is greater than 768 MB. If the RMA
>> +      size is less than 768 MB, the kernel does not export the
>> +      /sys/kernel/fadump/bootargs_append sysfs node.
> Reviewed-by: Mahesh Salgaonkar <mahesh at linux.ibm.com>

Thanks for the review.

- Sourabh Jain