TF-A, short for Trusted Firmware-A, is an open-source project initiated by ARM to provide a reference implementation of secure world firmware for ARMv7-A and ARMv8-A architectures. Specifically, TF-A is designed to execute at the highest Exception Level (EL-3) on ARM processors, serving as the Trusted Execution Environment (TEE) firmware in systems that utilize ARM TrustZone technology.
TF-A plays a crucial role in establishing a secure foundation for ARM-based systems, particularly those leveraging TrustZone technology. It contributes to the overall security posture of devices by ensuring the integrity and confidentiality of trusted code and data during the boot process and execution of secure applications.
TF-A (ARM Trusted Firmware-A), developed by ARM, operates at the highest privilege level (EL-3) under ARMv8-A, providing APIs for switching between the secure world and non-secure world. After TF-A completes initialization, it jumps to execute U-Boot (already loaded into DRAM by x-boot).
A secure monitor which runs at EL3.
Responsible for running OP-TEE (BL32).
Responsible for running U-Boot (BL33).
Core 0 brings up OP-TEE.
Core 0 jumps to run U-Boot and then run Linux.
Linux wake up core 1, 2 and 3.
