[RFC v4 PATCH 2/5] powerpc/crash hp: introduce a new config option CRASH_HOTPLUG

[Sourabh Jain <sourabhjain@linux.ibm.com>]

The option CRASH_HOTPLUG enables, in kernel update to kexec segments on
hotplug events.

All the updates needed on the capture kernel load path in the kernel for
both kexec_load and kexec_file_load system will be kept under this config.

Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Reviewed-by: Eric DeVolder <eric.devolder@oracle.com>
---
 arch/powerpc/Kconfig | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index b779603978e1..777db33f75b5 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -623,6 +623,17 @@ config FA_DUMP
 	  If unsure, say "y". Only special kernels like petitboot may
 	  need to say "N" here.
 
+config CRASH_HOTPLUG
+	bool "kernel updates of crash kexec segments"
+	depends on CRASH_DUMP && (HOTPLUG_CPU) && KEXEC_FILE
+	help
+	  An efficient way to keep the capture kernel up-to-date with CPU
+	  hotplug events. On CPU hotplug event the kexec segments of capture
+	  kernel becomes stale and need to be updated with latest CPU data.
+	  In this method the kernel performs minimal update to only relevant
+	  kexec segments on CPU hotplug event, instead of triggering full
+	  capture kernel reload from userspace using udev rule.
+
 config PRESERVE_FA_DUMP
 	bool "Preserve Firmware-assisted dump"
 	depends on PPC64 && PPC_POWERNV && !FA_DUMP
-- 
2.35.1