LPC55s69 : hardfault in FFR region

[EugeneHiihtaja]

Hi !

I have environment based on SDK example free_rtos_mpu_s/ns couple.

I have applied  S-User ( NS-User by default) for last 32KB flash block : 0x98000 - 0x9FFFF where FFR region located also.

I dosn't have any access from nonsecure part to this area at all.

But HardFault is indicate it :

Entering HardFault interrupt!
SCB->BFSR:PRECISERR fault: Precise data access error.
Address that caused secure bus violation is 0x9FCF4.

Additional AHB secure controller error information:
Secure error at AHB layer 0.
Address that caused secure violation is 0x9FCF4.
Secure error caused by bus master number 0.
Security level of master 1.
Secure error happened during read data access.

Is any idea what NXP components can indirectly to read this area ?

Some FSL drivers or what ?

For my undestanding I should keep this area with Secure attributes and any access from Nonsecure code should be forbidden.

Regards,

Eugene

[ZhangJennie]

Hi Eugene

Secure region can access NS region.

BUT NS region can't access secure region directly. it must get through NSC . see below 

For demo code, see ..\SDK_2.7.0_LPCXpresso55S69\boards\lpcxpresso55s69\trustzone_examples\hello_world.

It includes how to call S region function from NS region.

Have a great day,
Jun Zhang

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[EugeneHiihtaja]

Hi ZhangJennie‌ !

NS and S world relation is clear for sure.

But some fsl drivers or what ever reads FFR locations and I can't apply S attributes to it.

FFR read is OK from secure side and noone shouldn't read it form nonsecure side.

But Hardfault generated if MPC settings bring S attribyte to that flash block.

It is weird a bit.

Regards,

Eugene

[ZhangJennie]

If you have specific problem, please detailed the steps of how to reproduce your issue with a NXP SDK demo code. This will save our time to reproduce. Thanks for your understanding.