phycore_mpc5554 idle thread exits when GDB invoked

[Peter Dufault]

I tried to figure out why I don't see any issues during normal debugging when I set breakpoints and then start GDB, I only have a problem when I hit ^C to enter GDB. Since bsp_idle_thread() is unusual in that the generated code has no return from subroutine:

0006ef44 <bsp_idle_thread>:
   6ef44:   48 00 00 00     b       6ef44 <bsp_idle_thread>

I hacked the bsp_idle_thread to be the following.  Now when I break into the debugger with ^C I'm in the "this_is_a_hack()" function, and I do not have any issues with pending interrupts and then winding up returning from bsp_idle_thread() and then calling bsp_reset().

Anyone have any ideas as to what could be causing this odd behavior?

void __attribute__ ((noinline)) this_is_a_hack() 
{   
  volatile int i; 
  for (i = 0; i < 1000000; i++) {   
  }
}
    
void *bsp_idle_thread(uintptr_t arg)
{
  while (true) {
    this_is_a_hack();
  }
 
  return NULL;
}


On Jun 3, 2014, at 07:19 , Peter Dufault <dufault at hda.com> wrote:

> I stumbled on something.  If I disconnect the ethernet it will work OK.  I also notice that if I hit a return at the serial console while within GDB it will do the same thing. Something about trying to resume with an interrupt pending is screwing things up.  It mustn't be clock tick interrupts, though, or maybe the clock is stopped and restarted but the other interrupts remain pending.

Peter
-----------------
Peter Dufault
HD Associates, Inc.      Software and System Engineering