How to examine the heap and stack of an RTEMS application using gdb?

Question

Is there a way to know exactly the address range of both the heap and the stack on an RTEMS application by using gdb? I know there's info proc mappings on Linux, but I don't think RTEMS has a /proc to begin with. Using x to examine memory would be great but I need to know the address range of both.

I know there are some tips in http://www.rtems.org/wiki/index.php/Debugging, but they themselves admit those are really crude estimates.

Answer 1

For the heap you can investigate the Heap_Control structure (defined at cpukit/score/include/rtems/score/heap.h) and the two variables, RTEMS_Malloc_Heap and _Workspace_Area. In particular you seem interested in the Heap_Control.area_begin and Heap_Control.area_end fields. The _Workspace_Area can be part of the heap or a separate memory region, and it holds the kernel data structures. The RTEMS_Malloc_Heap points to the Heap_Control describing the traditional C program heap.

For the stack, you can look at the Thread_Start_information structure (defined at cpukit/score/include/rtems/score/thread.h) contained in the Thread_Control associated with the thread whose stack you want to examine. You can get a pointer to the executing thread with the _Thread_Executing macro.

Answer 2

I have also tired to figure out same things one week back.But i came a cross that it totally depend on the Os and the implementation of the code.As gcc compiler takes 8mb of memory for stack and the range of there address will keep on changing as u compile it again and again.So u have to know where it store whether in contiguous stack or a stack where blocks are interleaved with heap blocks in memory.follow the link u will find some hint

http://gribblelab.org/CBootcamp/7_Memory_Stack_vs_Heap.html