Hi,

 

I don’t believe this is the right approach.

 

TF-M currently includes a non-secure side application (integration test) which is built together with the secure side. This is also reflected in “flash_layout.h” and “region_defs.h” which mixes defines for the secure and non-secure side.

 

While this might be convenient within TF-M current build setup for the platforms that are supported, it causes issues in real applications and when trying to make this scalable across a large number of platforms. We have seen those issues already while working on providing TF-M as a CMSIS-Pack.

 

There should be a clean separation of files between the secure and non-secure side.

 

The mentioned header files should not be imposed to the non-secure side.

 

Typically non-secure software will have a device specific linker script which will only need to know limited information from the memory layout (non-secure code and data location). Also the secure side might be prebuilt and the non-secure side developed and built separately.

 

One possible solution is to use a CMSIS-Zone to partition the memory layout on a global level and then splitting it to sub-systems for secure and non-secure and exporting only relevant information for each side. This approach will be used also with TF-M CMSIS-Pack which should be available soon.

 

Best regards,

Robert

 

 

Hi,

 

The headers `flash_layout.h` and `region_defs.h` as the name suggests defines layout of flash and how different regions are organised in flash and ram respectively. These headers define the location of Bootloader if any, secure and non-secure firmware in flash and these defines are used in the linker scripts. As far as I can tell, these headers will be used by NS RTOS without any modifications, I can confirm that, this is the case in Mbed OS.

 

Since these headers are usually imported into NS RTOS without any modifications, I propose that we export these headers as part of the build.

 

Thanks,

Dev

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