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.

To find out more about Trusted Firmware-A, please view the full documentation that is available through trustedfirmware.org.

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