- The OpenSTLinux distribution running on the Arm® Cortex®-A, includes:
- The OpenSTLinux BSP with:
- The boot chain based on TF-A BL2 and U-Boot, FSBL-A and SSBL-A.
- The secure monitor based on TF-A BL31 or OP-TEE depending on Cortex®-A architecture, running on the Arm® Cortex®-A in secure mode.
- The OP-TEE secure OS running on the Arm® Cortex®-A in secure mode.
- The Linux® kernel running on the Arm® Cortex®-A in nonsecure mode.
- The Linux middleware relying on the BSP to provide API to the Applications that typically interact with the user via the display, the touchscreen, etc.
- The OP-TEE Trusted Applications (TA) relying on the OP-TEE core for secrets operations (not visible from the Linux and other software components).
- The OpenSTLinux BSP with:
The figure below is clickable so that the user can directly jump to one of the sub-levels listed above.
OpenSTLinux architecture overview
Arm® is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere. 
Arm® is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.