  Processing sensitive data and deploying well-designed Intellectual Property
(IP) cores on remote Field Programmable Gate Array (FPGA) are prone to private
data leakage and IP theft. One effective solution is constructing Trusted
Execution Environment (TEE) on FPGA-SoCs (FPGA System on Chips). Researchers
have integrated this type TEE with Trusted Platform Module (TPM)-based trusted
boot, denoted as FPGA-SoC tbTEE. But there is no effort on secure and trusted
runtime customization of FPGA-SoC TEE. This paper extends FPGA-SoC tbTEE to
build Runtime Customizable TEE (RCTEE) on FPGA-SoC by additive three major
components (our work): 1) CrloadIP, which can load an IP core at runtime such
that RCTEE can be adjusted dynamically and securely; 2) CexecIP, which can not
only execute an IP core without modifying the operating system of FPGA-SoC TEE,
but also prevent insider attacks from executing IPs deployed in RCTEE; 3)
CremoAT, which can provide the newly measured RCTEE state and establish a
secure and trusted communication path between remote verifiers and RCTEE. We
conduct a security analysis of RCTEE and its performance evaluation on Xilinx
Zynq UltraScale+ XCZU15EG 2FFVB1156 MPSoC.
