How to develop an OP-TEE Trusted Application

Applicable for

STM32MP13x lines, STM32MP15x lines

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This article describes how to develop a Trusted Application for OP-TEE using an OpenSTLinux environment.

1. Starting from an example

The simplest way to begin the development of a new OP-TEE Trusted Application is to start from a minimal example. Let's take the hello_world example from the official optee_examples.git repository:

 PC $> git clone https://github.com/linaro-swg/optee_examples

2. Build

At this point it is assumed OpenSTLinux SDK is installed and set up correctly.

The Trusted Application can be built by running make. For instance with the "hello_world" example:

 PC $> make -C optee_examples/hello_world
 make[1]: Entering directory '…/optee_examples/hello_world/host'
 [...]
 make[1]: Leaving directory '…/optee_examples/hello_world/host'
 make[1]: Entering directory '…/optee_examples/hello_world/ta'
 [...]
 make[1]: Leaving directory '…/optee_examples/hello_world/ta'

3. Run

Once built, the Trusted Application and its client must be copied onto the running system at the expected location. For instance with the "hello_world" example, using scp:

 PC $> scp optee_examples/hello_world/host/optee_example_hello_world root@<board ip address>:/usr/bin
 PC $> scp optee_examples/hello_world/ta/8aaaf200-2450-11e4-abe2-0002a5d5c51b.ta root@<board ip address>:/lib/optee_armtz/

Now it can be executed easily from the running system:

 root@stm32mp1:~# optee_example_hello_world
 Invoking TA to increment 42
 TA incremented value to 43

4. Going further

To get more information on how to develop on OP-TEE Trusted Application, please refer to https://optee.readthedocs.io/en/latest/building/trusted_applications.html

Open portable trusted execution environment

Software development kit (A programming package that enables a programmer to develop applications for a specific platform.)

Trusted application