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-rw-r--r--Documentation/ABI/testing/sysfs-kernel-fadump3
-rw-r--r--Documentation/arch/powerpc/firmware-assisted-dump.rst22
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:
-----------------------