U3 / WBA. privileged read/write region that is readonly otherwise, without using MPU ?

[Thomas Roell]

The issue feels really simple, and it's easy to do on N6.

 

At the core, I am running out of MPU regions as there are only 8 available. So it would be nice to have a small chunk of SRAM, where privileged code can share data with unprivileged code. Say a status or something like this.

GTZC only controls both read and write. So I cannot say that a single 512 byte block is read/write for privileged code, but read only for unprivileged. 

 

[Bubbles]

Hi ​@Thomas Roell ,

looks like my previous answer was lost in the community platform migration.

I suggested to use the tamper backup registers.

BR,

J

[Thomas Roell]

I had seen the previous answer. Looks like the move to the new platform lost a lot of the old content.

 

For things like the current TLS pointer or such TAMP might be a good solution, but for anything else, just too limited. But a great idea to for the most important items.

 

- Thomas