The Header File Config System

The header file configurations system is used to fine-tune component options.

The following diagram shows how the system works.

A config_tfm.h file collects customized configurations, including platform customized and project specific settings. Each component has a config_<comp_name>.h which includes the config_tfm.h first and then provides default values for each config option of the component as well as necessary validations on config dependencies. Source files then include component header files when necessary.

The config_tfm.h includes a customized project config file provided via compile definition PROJECT_CONFIG_HEADER_FILE. Users set the corresponding CMake variable PROJECT_CONFIG_HEADER_FILE with the full path of the configuration header file. A platform can adjust or place restriction on config options by providing a config_tfm_target.h under the root folder of their platforms. If the build system finds the file, it sets the TARGET_CONFIG_HEADER_FILE compile definition.

#ifdef PROJECT_CONFIG_HEADER_FILE
#include PROJECT_CONFIG_HEADER_FILE
#endif

#ifdef TARGET_CONFIG_HEADER_FILE
#include TARGET_CONFIG_HEADER_FILE
#endif

The project config header file can be

Generated by the TF-M Kconfig system <kconfig_system>
One of the header files of Profiles <tf-m_profiles>, set via the TFM_PROFILE build option.
Manually customized profile based on pre-set profiles.

It is expected that all Component options are included in the header file to explicitly set values for each option. Refer to Base Configuration for details the base configurations.