compute and display stack high water mark in 'freertos task' (GCC-312)

[danc86]

Essentially follows the same logic as in the FreeRTOS uxTaskGetStackHighWaterMark() function, except we also need to guess the stack growth direction (portSTACK_GROWTH macro).

Example output:

(gdb) freertos task
CPU	 - Processing on CPU number
ID	 - TCB_t task memory address
PRI	 - Task priority
B_PRI	 - Base priority.
SL	 - Free/unused stack size.
SHW	 - Stack high water mark (amount of stack space that has not been touched).

 CPU                            ID    NAME    STATUS PRI B_PRI MUTEXES_HELD   SL SHW
---- ----------------------------- ------- --------- --- ----- ------------ ---- ---
CPU0  0x1043f0 <xIdleTaskTCB.4917>    IDLE     ready   0     0            0  120 120
     0x104448 <xTimerTaskTCB.4924> Tmr Svc suspended   6     6            0  304 304
           0x10292c <xAppsTaskObj>    main suspended   5     5            0 1012 404
        0x108e38 <dmem_heap+18840> evtloop delayed_1   3     3            0 8384 368

I only have RISC-V targets (stack grows downwards) so I haven't actually tested the code path for handling stack growing upwards. But I think it will work... :-)

[Lapshin]

@danc86, thanks for the contribution!

That's a pretty nice implementation. Only one thing I would like to ask you to improve:

Could you please check the stack growth direction with frame addresses from the backtrace?

• This requires having a task with more than one frame. I think this is not going to be a problem

This will give us the right direction without guessing...

This could be done once if the direction is unknown, not needed to check the direction every time