TFM-ITS out of space

[Cla]

When using the `tfm` `its` service we run into a PSA_ERROR_INSUFFICIENT_STORAGE error.
We only use ~12 assets of maximum ~300 bytes of size (most are smaller and the one running into the error is only a few bytes).
We write to it using `psa_its_set` and read from it using `psa_its_get`.
If we update we directly use `psa_its_set` again on the same id. Is this the correct approach? Do we need to call `psa_its_remove` first?

Thanks in advance.


[Cla]

I tested and the answer seems to be no, "remove" is not needed before the next "set".

But is `psa_its` thread safe?

[Cla]

Or maybe to rephrase:
In a multithreaded environment different threads execute `psa_its_get` and `psa_its_set` on the same ids. Is it guaranteed, that they all will have a consistent view of the data? Or should access to it be synchronized by the user for example with mutexes to avoid data races?

[Hakon]

I believe it should be thread safe, but I'm not sure. I have asked this question internally.

[Cla]

Thank you.

[Hakon]

Apparently all calls to TF-M goes through a single mutex. Unfortunately this is not well documented, so it's hard to find information about this at the moment.