Debugging Cortex-M33 application started by Linux remoteproc on STM32MP257

[Hs26]

Hi ST team,

I am working with an STM32MP257 where Linux runs on the Cortex-A35 and a FreeRTOS application runs on the Cortex-M33. The M33 firmware is loaded and started by Linux using remoteproc.

The application is running correctly, but I would like to understand the recommended workflow for debugging the M33 application.

I have read the "Debug support" section of RM0457 and understand that the M33 can be accessed through the shared SWD/JTAG interface by selecting the appropriate Access Port. However, I'm still not clear on the recommended debug workflow when the M33 is managed by remoteproc.

My questions are:

• Can STM32CubeIDE/ST-LINK attach to an already running M33 started by remoteproc, or should the M33 be stopped first?
• If Linux has already loaded the firmware, should the debugger load only the ELF symbols instead of downloading the application again?
• Is there any special OpenOCD/ST-LINK or CubeIDE configuration required for this use case?
• Is there an ST application note or example demonstrating the recommended workflow?

My goal is to debug the M33 application with breakpoints, single-stepping, and variable inspection, similar to debugging a standalone STM32 MCU, while Linux continues to run on the A35.

Any guidance would be appreciated.

Thank you.

[Olivier GALLIEN]

Hi ​@Hs26,

I guess you can start by looking at Develop on Arm® Cortex®-M33 - stm32mpu it will drive you to initial step setting up debug on CM33

Hope it help 

Olivier