Not able to calculate TLS for ARM64 architecture

[OSS Dev]

I am working on delve to provide support for AARCH64 but facing problem in calculation of TLS. I have taken same approach what is taken for X86 architecture ie: using ptrace..

ptrace(PTRACE_GETREGSET,pid,uintptr(elf.NT_ARM_TLS),uintptr(unsafe.Pointer(&iovec)))
but always getting value "0"

I tried to find out TLS in our sample code (in C language not in GO lang) and able to calculate correctly
with following function..
ret = ptrace (PTRACE_GETREGSET, pid,(void*)NT_ARM_TLS, (void*)&iovec);

I am suspecting that NT_ARM_TLS is not handled in go lang , 

please suggest