4.5 KiB
Target of this port
This port adds the support that FreeRTOS applications can call the secure services in Trusted Firmware M(TF-M) through Platform Security Architecture (PSA) API based on the ARM Cortex-M23, Cortex-M33, Cortex-M55 and Cortex-M85 platform.
The Platform Security Architecture (PSA) makes it quicker, easier and cheaper to design security into a device from the ground up. PSA is made up of four key stages: analyze, architect, implement, and certify. See PSA Resource Page.
TF-M is an open source project. It provides a reference implementation of PSA for Arm M-profile architecture. Please get the details from this link.
Derivation of the source code
os_wrapper_freertos.c
The implementation of APIs which are defined in/interface/include/os_wrapper/mutex.h
in trusted-firmware-m (tag: TF-Mv2.0.0). The implementation is based on FreeRTOS mutex type semaphore.
Usage notes
To build a project based on this port:
- Step 1: build the secure image. Please follow the Build the Secure Side section for details.
- Step 2: build the nonsecure image. Please follow the Build the Non-Secure Side for details.
Build the Secure Side
Get the TF-M source code
See the link to get the source code. This port is supported by TF-M version tag: TF-Mv2.0.0.
Build TF-M
Please refer to this link to build the secure side.
Note: TFM_NS_MANAGE_NSID
must be configured as "OFF" when building TF-M.
Build the Non-Secure Side
Please copy all the files in freertos_kernel/portable/GCC/ARM_CM[23|33|55|85]_NTZ
into the freertos_kernel/portable/ThirdParty/GCC/ARM_TFM
folder before using this port. Note that TrustZone is enabled in this port. The TF-M runs in the Secure Side.
Please call the API tfm_ns_interface_init()
which is defined in /interface/src/os_wrapper/tfm_ns_interface_rtos.c
by trusted-firmware-m (tag: TF-Mv2.0.0) at the very beginning of your application. Otherwise, it will always fail when calling a TF-M service in the Nonsecure Side.
Configuration in FreeRTOS kernel
-
configRUN_FREERTOS_SECURE_ONLY
This macro should be configured as 0. In this port, TF-M runs in the Secure Side while FreeRTOS Kernel runs in the Non-Secure Side. -
configENABLE_FPU
The setting of this macro is decided by the setting in Secure Side which is platform-specific. If the Secure Side enables Non-Secure access to FPU, then this macro can be configured as 0 or 1. Otherwise, this macro can only be configured as 0. Please note that Cortex-M23 does not support FPU. Please refer to TF-M documentation for FPU usage on the Non-Secure side. -
configENABLE_MVE
The setting of this macro is decided by the setting in Secure Side which is platform-specific. If the Secure Side enables Non-Secure access to MVE, then this macro can be configured as 0 or 1. Otherwise, this macro can only be configured as 0. Please note that only Cortex-M55 and Cortex-M85 support MVE. Please refer to TF-M documentation for MVE usage on the Non-Secure side. -
configENABLE_TRUSTZONE
This macro should be configured as 0 because TF-M doesn't use the secure context management function of FreeRTOS. New secure context management might be introduced when TF-M supports multiple secure context.
Integrate TF-M Non-Secure interface with FreeRTOS project
To enable calling TF-M services by the Non-Secure Side, the files below should be included in the FreeRTOS project and built together.
- files in
trusted-firmware-m/build/api_ns/interface/src
These files contain the implementation of PSA Functional Developer APIs which can be called by Non-Secure Side directly and PSA Firmware Framework APIs in the IPC model. These files should be taken as part of the Non-Secure source code. - files in
trusted-firmware-m/build/api_ns/interface/include
These files are the necessary header files to call TF-M services. trusted-firmware-m/build/api_ns/interface/lib/s_veneers.o
This object file contains all the Non-Secure callable functions exported by TF-M and it should be linked when generating the Non-Secure image.
Copyright (c) 2020-2024, Arm Limited. All rights reserved.