Kinetis Microcontrollers中的主题 Re: How to verify safe stack usage on KL17?

How to verify safe stack usage on KL17?

rickstuart — Fri, 02 Sep 2016 20:49:48 GMT

We are about mid point in our development and would like to test if our stack usage is safe (not close to overflowing) on our KL17 processor? What tools are available to a developer to make this assessment? We are using the IAR Workbench IDE.

-thanks

Re: How to verify safe stack usage on KL17?

xiangjun_rong — Tue, 13 Sep 2016 09:31:04 GMT

Hi, Rick,

I think we have not the tools to check if the stack is safe. But I think you can write the stack with a pattern, then running the code and check if pattern has been changed for the out of range of stack memory.

Hope it can help you.

Xiangjun Rong

Re: How to verify safe stack usage on KL17?

rastislav_pavlanin — Tue, 13 Sep 2016 10:49:18 GMT

Hello Rick,

I have used this approach to analyses the stack in my applications:

IAR Stack usage analysis for RX

and get it really usefull.

regards

Re: How to verify safe stack usage on KL17?

bobpaddock — Tue, 13 Sep 2016 12:59:43 GMT

Moving the stack from the top of RAM to near the bottom is an often over looked method.

When it overflows it will generate an exception rather than silently corrupting things.

Explained here: Are We Shooting Ourselves in the Foot with Stack Overflow? « State Space

How to read the stack pointer:

In Generic C, a good tools set should complain about returning the address of a local variable:

/*
* void *CheckStackDepth( void )
* {
* volatile uint32_t dummy; // Put a variable on the stack
* return( (void *) &dummy ); // Return its address - therefore the (approx.) present SP value
* }
*/

In GCC:

static __inline__ void *sp_get(void)
{
void *sp;

__asm__ __volatile__ ("mrs %0, msp" : "=r"(sp));

return( sp );
}

I call sp_get() in IRQs then test and save to a global variable (which in general should be avoided) that will show the stack depth. Something different would need done if have nested IRQs.