LPC55S69 : call nonsecure function from secure ISR

EugeneHiihtaja — Fri, 15 Nov 2019 20:53:47 GMT

Hi !

I would like to handle interrupt on secure side.

When interrupt occurs, I should be able to call function on nonsecure side ( from Isecure SR context ) and it will send message to FreeRTOS task.

If interrupt handled on nonsecure side, it is not a problem to send message to RTOS becouse it run on nonsecure side also.

I have check all SDK examples and always all calls from nonsecure to secure side.

But how to compose this call :

• BXLNS: Branch with Link Exchange Non Secure - calls a subroutine in NS memory.
On executing either the BXNS or BXLNS instructions the CPU-S will also change to the
Non-secure state (CPU-NS) and thus be in the correct state for executing out of NS
memory.

How secure side can know where known function located on nonsecure side ?

If secure side in ISR context , does nonsecure will look as in ISR context and I should use freertos function for ISR context ?

Regards,

Eugene

Re: LPC55S69 : call nonsecure function from secure ISR

Sabina_Bruce — Tue, 19 Nov 2019 15:44:53 GMT

Hello Eugene,

Please refer attached training slides.

Secure code has access right to non secure regions. But Non-Secure code only allowed to access Secure code APIs which are defined in veneer tables.

Let me know if you have further questions.

Best Regards,

Sabina

LPC MicrocontrollersのトピックLPC55S69 : call nonsecure function from secure ISR

LPC55S69 : call nonsecure function from secure ISR

Re: LPC55S69 : call nonsecure function from secure ISR