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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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

authored by

Sourabh Jain and committed by
Madhavan Srinivasan 61c403b5 fdc44538

+24 -1
+2 -1
Documentation/ABI/testing/sysfs-kernel-fadump
··· 55 55 Contact: linuxppc-dev@lists.ozlabs.org 56 56 Description: read/write 57 57 This is a special sysfs file available to setup additional 58 - parameters to be passed to capture kernel. 58 + parameters to be passed to capture kernel. For HASH MMU it 59 + is exported only if RMA size higher than 768MB.
+22
Documentation/arch/powerpc/firmware-assisted-dump.rst
··· 120 120 e.g. 121 121 # echo 1 > /sys/firmware/opal/mpipl/release_core 122 122 123 + -- Support for Additional Kernel Arguments in Fadump 124 + Fadump has a feature that allows passing additional kernel arguments 125 + to the fadump kernel. This feature was primarily designed to disable 126 + kernel functionalities that are not required for the fadump kernel 127 + and to reduce its memory footprint while collecting the dump. 128 + 129 + Command to Add Additional Kernel Parameters to Fadump: 130 + e.g. 131 + # echo "nr_cpus=16" > /sys/kernel/fadump/bootargs_append 132 + 133 + The above command is sufficient to add additional arguments to fadump. 134 + An explicit service restart is not required. 135 + 136 + Command to Retrieve the Additional Fadump Arguments: 137 + e.g. 138 + # cat /sys/kernel/fadump/bootargs_append 139 + 140 + Note: Additional kernel arguments for fadump with HASH MMU is only 141 + supported if the RMA size is greater than 768 MB. If the RMA 142 + size is less than 768 MB, the kernel does not export the 143 + /sys/kernel/fadump/bootargs_append sysfs node. 144 + 123 145 Implementation details: 124 146 ----------------------- 125 147