STM32H573i-DK with Trustzone: HardFault with ThreadX and NSC Calls

[funkii]

Hi everyone,

I'm currently trying to switch to the Secure World within ThreadX using a NSC function (I use an empty function for debugging, but the problem does persist also if I do anything there).

Problem:

If i call my NSC function in the NonSecure main.c before the MX_ThreadX_Init() it works fine.

If i call it after it in some application, it does not work.

More precise, i get an HardFault with the STKERR, BFARVALID, PRECISERR, bit set in the BFSR register. see here for more infos about the registers . Also the stackpointer sp is at the end of the secure RAM (Increasing the RAM does not help, it then still is at the end) 

 

After debugging a while, I found after what instruction/function my error occurs. 

In _tx_initialize_kernel_enter() in the file tx_initialize_kernel_enter.c the function _tx_thread_secure_stack_initialize() gets executed by the macro TX_PORT_SPECIFIC_PRE_INITIALIZATION. 

Before that call, the NSC function works, after it I go straight to the HardFault handler. If i just comment out that callto the secure stack initialize, everything seems to just works fine, including the rest of my setup.

I tried to look at the function in Middlewares/ST/threadx/ports/cortex_m33/gnu/src/tx_thread_secure_stack_initialize.S but I don't really understand whats happening there tbh.

 

Anyone got an Idea why this is happening or what good the secure stack init does? Is it a problem if I just remove it from my code?

 

Best,

funkii

 

[STea]

Hello @funkii ,

Did you try to increase the stack size? because it seems from a first glance that the stack allocation done by _tx_thread_secure_stack_initialize() eats up the stack .

BR

[funkii]

Hi @STea ,

thank you for your reply.

Yes, i have tried to increase the _Min_Stack_size in the STM32H573IIKXQ_FLASH.ld file both of the secure and nonsecure subproject with the values 0x400, 0x4000 and 0x40000. 

Unfortunately this did not change anything.

Best and sorry for my delayed response,

funkii

[Jocelyn RICARD]

Hello @funkii 

please have a look to threadX example with TrustZone:

STM32Cube_FW_H5_V1.1.1\Projects\NUCLEO-H563ZI\Applications\ThreadX\Tx_SecureLEDToggle_TrustZone\

Best regards

Jocelyn