Hi everyone,
The existing HAL interface for isolation hardware is not unified, we have to call several interfaces to setup isolation boundaries.
Hence, a deeper abstracted interface are provided. Here are the details:
- It assumes the hardware resources usages are decided by system designer. Hence there are couple of listed hardware data in the platform code, now most of them are defined in C sources. - When a partition is referencing peripheral (represented as MMIO in FFM), the manifest tooling would link specified resources with the data defined in platform. Now it is using a naming pattern, to let the partition found the resources defined above (now it uses linker to do this). - A HAL API 'tfm_hal_bind_partition' is called when a partition runtime structure is created. This API tells partition info to platform, let platform return an encoded 'p_boundaries' for SPM binding partition with platform. - When boundaries related operations happen in future, SPM would delivery this 'p_boundaries' back to platform, let platform perform boundary setup and check, such as boundary switch or memory check. SPM won't care about the hardware specific settings any more, such as privilged, non-secure/secure and how many MMIO the partition claimed, even the MPU/MPC/PPC things. - Resources defined in platform sources but not referenced would be stripped by toolchain flag. Resources not defined but referenced by partition would generate a linker error, as symbol can't be resolved.
We created a patch to showcase the usage on AN521: https://review.trustedfirmware.org/c/TF-M/trusted-firmware-m/+/11036
This patch applies a simple encoding for all isolation levels. You can check how the p_boundaries is used under different isolation levels. Platform can use other encoding mechanism if applicable.
Now come to the request: Please review this patch, and port similar HAL API into your platform. We are maintaining the default platforms such as AN521, AN519 and MUSCA_B1, but it need so much effort on port to all the platforms.
Current CI cannot pass on this patch (as it contains modification for one platform only), our first goal is to let CI pass build on all checked platforms, and then please platform owner ensures it works on your platform.
Any feedbacks are welcome. Thank you very much!
/Ken