Stack overflow detection on Cortex-m3 with MPU

wella wrote on Friday, August 14, 2015:


just an idea, has anyone played with stack overflow detection by using the MPU? E.g. use lowest 32 bytes of the stack area as a protected area and configure the MPU (e.g. region 7) as a non-accessible memory? It does not protect from sp manual adjusment but should detect runtime push-pop failures.

I am looking for a correct placement of the MPU set/reconfigure function, some kind of trace macros…


rtel wrote on Friday, August 14, 2015:

FreeRTOS MPU (which is not that well maintained as not many people use it compared to the non-MPU version) uses one MPU region to protect from stack overflows. The advantage is stack overflows are detected before they happen, rathter than after which is the case when the detection is done in software. The disadvantages are the alignment and size restrictions of the Cortex-M MPU are so strict you have to create huge stacks and fiddle the code or linker script to ensure they start on the correct memory boundaries (power of 2, if I recall correctly).


wella wrote on Friday, August 14, 2015:

Thank you, I have to check the MPU variant again. I did not notice that such functionality is already included. I am aware of wasting stack memory because the lowest the cm3 MPU protected area is 32 bytes and the region start address must be aligned to its size.