[seL4] seL4 how to access el3 secure world on ARM platfrom

Hi： We want to create component driver who need to access ARM el3 secure world to read/write hardware register. But I found that seL4 did not offer capability to call smc function for component of native world. Which cap that already existed can offer the syscall or create new smc cap ? Is there some plan to support it ? Thank you very much.