Debugging basic BSP tasking functionality

Sebastian Huber sebastian.huber at
Wed Apr 17 11:16:46 UTC 2013

On 04/17/2013 12:32 PM, Matthew J Fletcher wrote:
> Hi,
>  >They should do it all in the same way.  The difference is that some BSPs use
> copy and >paste start.S files.  I removed a lot of copy and paste from the ARM
> port with mechanical >changes.  It is possible that this broke some BSPs
> including the rtl22xx_t.
> I am using the stable 4.10.2 sources BTW. If the above still applies what areas
> were changed, so i can investigate ?

I changed some linker command files and the interrupt support, e.g.

You can try also a RTEMS 4.9 version.

>  >The stack checker inspects the pattern (0xFEEDF00D, 0x0BAD0D06, 0xDEADF00D,
>  >0x600D0D06) at the end of the stack area.  One of these values must be
> modified to the >the blown stack message.  You can set the write break point here.
> Are you sure ? looking at the code if the above pattern area is overwritten
> then i would see a printk with "damaged pattern area". I dont see that, and
> also when examining memory i can see the pattern is intact.
> The other part of the stack check, is making sure the frame pointer is in range
> of the stack, it looks like its this check that fails.
> Indeed within Stack_check_Frame_pointer_in_range() GCC's
> __builtin_frame_address(0); is returning a sp of 0x814d299c, which is outside
> the stack range of the IDLE thread 0x814d060c -> 0x814d1610
> the callstack is,..
> Stack_check_Frame_pointer_in_range() at check.c:69 0x81180f6e
> rtems_stack_checker_switch_extension() at check.c:276 0x81180f6e
> _User_extensions_Thread_switch() at userextthreadswitch.c:41 0x8118cbaa
> _Thread_Dispatch() at threaddispatch.c:128 0x8118bce6
> _Thread_Enable_dispatch() at threaddispatch.c:59 0x8118bd5e
> rtems_task_delete() at taskdelete.c:94 0x81189750
> Init() at startup.c:241 0x81007840

Here a context switch from the Init to the idle (I guess) thread happens.  The 
_User_extensions_Thread_switch() is called before the context switch and the 
running thread is checked.  So a sp of 0x814d299c must be in the range of the 
Init stack area.

What is the output of

nm your-app.exe | grep 'bsp_\(section\|stack\)' | sort


Sebastian Huber, embedded brains GmbH

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