icc_sre_el2 register not recognised with arm-none-eabi

I am trying to access the ARMV8 system register icc_sre_el2 but get an unknown or missing system register error.

See below for the list of available registers for ARMV8

https://developer.arm.com/docs/ddi0595/e/aarch64-system-registers

When using some other registers from the list the build is successful. But anything with icc_, ich_ prefixes produces a failure.

What do I need to do to fix this? 

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