As cmake is still the build system, let me check the cmake related feature – but need to wait the build system change get merged then we can take a look where to start.

BR.

/Ken

From: TF-M <tf-m-bounces@lists.trustedfirmware.org> On Behalf Of Gyorgy Szing via TF-M
Sent: Tuesday, September 22, 2020 4:43 PM
To: tf-m@lists.trustedfirmware.org
Cc: nd <nd@arm.com>
Subject: Re: [TF-M] Proposal to separate SCT/LD into each platform folder

Hi Ken,

I think templating is a good approach here, the current C preprocessor based solution is a very limited implementation of this.
I see two main contenders for templating:

cmake has built in support for templating with the configure_file() [1] command. This would move ownership of this information info the build scripts, which are the focus point for such info already. A cmake based solution would feel more native to the existing system. On the other hand other solutions might have more features, which could lead to easier to read template files. Also cmake as a template engine is not that widely adopted.
jinja2 [2]. A widely adopted and more feature rich templating engine. TF-M already uses it for manifest file handling. I suggest using yahsa [3] instead of a custom pyhton script as the cli frontend though. This could speed up development as long as no complex processing is needed and the templates can be filled based on “simple” values.

Which of the above is the best for the task depends on template file readability and on complexity of the task. It could be nice if a clean split could be made, and we could stop using the C preprocessor based processing completely.

“Not sure if all these format support #include”
The build system works around that by implementing a compiler specific cmake function to add the pre-processing step for compilers not supporting pre-processing out of the box.

/George

[1] https://cmake.org/cmake/help/v3.18/command/configure_file.html
[2] https://jinja.palletsprojects.com/en/2.11.x/
[3] https://github.com/kblomqvist/yasha

From: TF-M <tf-m-bounces@lists.trustedfirmware.org> On Behalf Of Ken Liu via TF-M
Sent: 22 September 2020 10:15
To: tf-m@lists.trustedfirmware.org
Cc: nd <nd@arm.com>
Subject: Re: [TF-M] Proposal to separate SCT/LD into each platform folder

Hi,

During the level3 prototyping, we found using a unified sct/ld/file would be hard because we are trying to cover platform-specific setting in ONE place.

The biggest concern of preventing spreading the LD is: if there are COMMON changes then every platform source needs to be updated.

I believe the COMMON change is the arrangement of ARoT and PRoT, those platform-specific things such as CODE_SRAM and MPU alignment issue should not be covered inside the common sct/ld/icf.

Not sure if all these format support #include but as we are using a template so it should be possible to put COMMON settings inside a COMMON template and let platform to contain these common part and then add the specific settings.

I have a rough idea (see above) and need more investigation, request for ideas/concerns about this part.

Thanks.

/Ken

From: TF-M <tf-m-bounces@lists.trustedfirmware.org> On Behalf Of Shawn Shan via TF-M
Sent: Wednesday, August 5, 2020 1:27 PM
To: tf-m@lists.trustedfirmware.org
Cc: nd <nd@arm.com>
Subject: [TF-M] Proposal to separate SCT/LD into each platform folder

Hi all,

There are many differences in linker scripts between each platform. Using a common_s.sct/ld makes it too complicated.

And at the same time, in order to achieve isolation level 3, the position of the sessions in scatter and linker script file needs to be adjusted.

The common linker scripts would be more complicated with isolation L3.

So I would like to propose to have dedicated linker scripts for platforms with enough differential arrangements.

What’s your opinion on this?

Best regards,

Shawn