After hotplug of secondary core, from where the execution start? What about peripheral register ie GIC register, are they resetted? Why and when hotplug required?
Do the below help answer your query?
cpuidle (hotplug):https://community.arm.com/oss-platforms/w/docs/529/cpuidle-hotplug
Arm Power State Coordination Interface Platform Design Document:https://developer.arm.com/documentation/den0022/