diff options
| author | Sourabh Jain <sourabhjain@linux.ibm.com> | 2025-01-23 17:12:54 +0530 |
|---|---|---|
| committer | Madhavan Srinivasan <maddy@linux.ibm.com> | 2025-02-11 10:53:00 +0530 |
| commit | 61c403b5d000b46b8703595ea16533d0cb2a2911 (patch) | |
| tree | b139f7e6ea6077537117fda5d7fd5dac7c5f5921 | |
| parent | fdc44538d57caf4e96f57d5f0d0c89c4aa079f94 (diff) | |
Documentation/powerpc/fadump: add additional parameter feature details
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.
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250123114254.200527-5-sourabhjain@linux.ibm.com
| -rw-r--r-- | Documentation/ABI/testing/sysfs-kernel-fadump | 3 | ||||
| -rw-r--r-- | Documentation/arch/powerpc/firmware-assisted-dump.rst | 22 |
2 files changed, 24 insertions, 1 deletions
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 @@ -55,4 +55,5 @@ Date: May 2024 Contact: linuxppc-dev@lists.ozlabs.org Description: read/write This is a special sysfs file available to setup additional - parameters to be passed to capture kernel. + parameters to be passed to capture kernel. For HASH MMU it + is exported only if RMA size higher than 768MB. diff --git a/Documentation/arch/powerpc/firmware-assisted-dump.rst b/Documentation/arch/powerpc/firmware-assisted-dump.rst index 7e37aadd1f77..7e266e749cd5 100644 --- a/Documentation/arch/powerpc/firmware-assisted-dump.rst +++ b/Documentation/arch/powerpc/firmware-assisted-dump.rst @@ -120,6 +120,28 @@ to ensure that crash data is preserved to process later. e.g. # echo 1 > /sys/firmware/opal/mpipl/release_core +-- 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. + Implementation details: ----------------------- |