This argument is used to test whether enclave share mapping between
parent and child process is usable.
Signed-off-by: Jia Zhang <zhang.jia@linux.alibaba.com>

In order to implement more ecall functions, it is necessary to
implement a general sgx entry point with ecall number to
corresponding ecall handler.
Signed-off-by: Jia Zhang <zhang.jia@linux.alibaba.com>

This new implementation inspires the design of https://github.com/jsakkine-intel/linux-sgx/tree/next/tools/testing/selftests/x86/sgx, which is a real enclave runtime.
Signed-off-by: Njack.wxz <wangxiaozhe@linux.alibaba.com>