Hi,

Partition is described through configuration in YAML files (manifests). This configuration includes following properties (see Adding Secure Partition - Add manifest):

• Name, type, priority, model, …
• List of services provided by partition
• MMIO regions
• List of IRQs
• Dependencies

Each platform should provide implementation of HAL which is specific to standard partitions like Crypto, ITS, etc. It’s mandatory to provide proper isolation of memory/peripheral that are used by platform specific code that provides HAL implementation or add a custom dependency for standard partition.

Currently platform can use following approaches to resolve the problem of extending YAML of standard TF-M partition:

• Create a platform specific copy of partition YAML, see https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/15639 as an example of such approach.
• Modify standard partition by introducing optional fields, see https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/17718.

These both solution are not flexible enough. It requires to modify platform independent code or maintain own copy of partition YAML file with needed changes.

I think it make sense to integrate partition YAML extension tool in TF-M. Platform/application should be able to provide manifest-extension file(s). Such manifest-extension file may provide additional properties which should be joined with properties provided by standard partition manifest files.

For example to solve problem for https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/15639 ARM RSS platform may provide following manifest-extension file with structure like this:

{

  "extensions": [

    {

      "name": "TFM_SP_INITIAL_ATTESTATION",

      "dependencies": [

        "TFM_MEASURED_BOOT"

      ]

    }

  ]

}

Tool which parses manifests should add a new dependency on "TFM_MEASURED_BOOT" to list of dependencies for "TFM_SP_INITIAL_ATTESTATION" partition.

Please, share your opinion on this topic.

Best regards,

Roman.