Trusted Firmware-A
Trusted Firmware-A (TF-A) is a reference implementation of secure world software
for Arm A-Profile architectures_ (Armv8-A and Armv7-A), including an Exception
Level 3 (EL3) Secure Monitor_. It provides a suitable starting point for
productization of secure world boot and runtime firmware, in either the AArch32
or AArch64 execution states.
TF-A implements Arm interface standards, including:
Power State Coordination Interface (PSCI)_Trusted Board Boot Requirements CLIENT (TBBR-CLIENT)_SMC Calling Convention_System Control and Management Interface (SCMI)_Software Delegated Exception Interface (SDEI)_
The code is designed to be portable and reusable across hardware platforms and software models that are based on the Armv8-A and Armv7-A architectures.
In collaboration with interested parties, we will continue to enhance TF-A with reference implementations of Arm standards to benefit developers working with Armv7-A and Armv8-A TrustZone technology.
Users are encouraged to do their own security validation, including penetration testing, on any secure world code derived from TF-A.
More Info and Documentation
To find out more about Trusted Firmware-A, please view the full documentation_
that is available through trustedfirmware.org_.
Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved.
.. _Armv7-A and Armv8-A: https://developer.arm.com/products/architecture/a-profile .. _Secure Monitor: http://www.arm.com/products/processors/technologies/trustzone/tee-smc.php .. Power State Coordination Interface (PSCI): PSCI .. _PSCI: https://developer.arm.com/documentation/den0022/latest .. _Trusted Board Boot Requirements CLIENT (TBBR-CLIENT): https://developer.arm.com/docs/den0006/latest .. _SMC Calling Convention: https://developer.arm.com/documentation/den0028/latest .. System Control and Management Interface (SCMI): SCMI .. _SCMI: https://developer.arm.com/documentation/den0056/latest .. Software Delegated Exception Interface (SDEI): SDEI .. _SDEI: https://developer.arm.com/documentation/den0054/latest .. _Arm A-Profile architectures: https://developer.arm.com/architectures/cpu-architecture/a-profile .. _view the full documentation: https://www.trustedfirmware.org/docs/tf-a .. _trustedfirmware.org: http://www.trustedfirmware.org