If FIQ is routed to EL3 can it read/write the GICv2 registers from EL3 even if Secure Extension are implemented by both ARM and GIC?

I need to use FIQ in linux which run in EL1 non secure world. On my platform both ARMv8 and GICv2 implements the Secure Extensions, so is there is no way to use the FIQ in EL1 without setting up and running Secure World software. But if FIQ is routed to EL3, can it be able to read/write to the GIC registers in a normal way in this FIQ mode of EL3, especially to acknowledge and clear the FIQ interrupt? I need to use FIQ to sample time critical events with very high frequency.