Unhandled Interrupt

netra — Wed, 27 Mar 2013 05:04:32 GMT

I want to write a code so, that i can know in run time which task is having unhand led interrupt . so,that i can restart that task again.

I am using MQX 3.5.

Thanks,

netra

Re: Unhandled Interrupt

drummer — Thu, 28 Mar 2013 14:01:04 GMT

I was having a similar issue with a task that was aborting due to "unhandeld interrupt". I put a counter into the while(1) loop and waited for the exception to occur. The counter was always stopped at 4. So I cycled through 4 times and single stepped until it crashed. I kept my eye on any changes to file handles and discovered that an essential file handle was being changed .

I then used the watchpoint feature to see when the memory location was being changed. It ended up being another task that was writing the bad data.

Re: Unhandled Interrupt

JerryFan — Mon, 01 Apr 2013 02:33:26 GMT

MQX has a way to figure that issue out. You can use _task_set_exception_handler to install a exception handler to capture what you want.Please refer the demo code below.

static void expt_frm_dump(pointer ext_frm_ptr)
{
  static char *expt_name[] = {
    "None",
    "Reset",
    "NMI",
    "HardFault",
    "MemManage",
    "BusFault",
    "UsageFault",
    "Rsvd",
    "Rsvd",
    "Rsvd",
    "SVCall",
    "Debug Monitor",
    "Rsvd",
    "PendSV",
    "SysTick"
  };

  uint_32 excpt_num = __get_PSR() & 0x1F;
  printf("Opps, bad thing happened.\n");
  if(excpt_num < 16){
    printf("The exception [%s] throw by TASK 0x%x\n",
         expt_name[excpt_num] , _task_get_id());
  
    printf("Dump the exception frame as :\n");
    printf("R0:\t0x%08x\n", *((uint_32 *)ext_frm_ptr));
    printf("R1:\t0x%08x\n", *((uint_32 *)ext_frm_ptr + 1));
    printf("R2:\t0x%08x\n", *((uint_32 *)ext_frm_ptr + 2));
    printf("R3:\t0x%08x\n", *((uint_32 *)ext_frm_ptr + 3));
    printf("R12:\t0x%08x\n", *((uint_32 *)ext_frm_ptr + 4));
    printf("LR:\t0x%08x\n", *((uint_32 *)ext_frm_ptr + 5));
    printf("PC:\t0x%08x\n", *((uint_32 *)ext_frm_ptr + 6));
    printf("PSR:\t0x%08x\n", *((uint_32 *)ext_frm_ptr + 7));
  }else{
    printf("The external interrupt %d occured while no handler to serve it.\n");
  }
}

void  task_exception_handler(_mqx_uint para, pointer stack_ptr)
{
#if 0
   __asm (
                "push {lr}        \n"
                "mrs r0, psp   \n"
                "bl    expt_frm_dump   \n"
                "pop {pc}       \n"
  );
#endif
    pointer expt_frm_ptr = (pointer)__get_PSP();
    expt_frm_dump(expt_frm_ptr);
}

void hello_task(unsigned long para)
{
  unsigned int *p_bad = (unsigned int *)0;

  printf("Hello, MQX\n");

  printf("Install the _int_exception_isr to replace the _int_default_isr\n");
  _int_install_exception_isr();



  /* Set the exception handler of the task */
  _task_set_exception_handler(_task_get_id(), task_exception_handler);
  *p = 0;     //This will issue a HardFault exception

  _task_block();
}

BTW, unhandeld interrupt should be definely avoided.

EDIT: Use C++ code highlight in the Advanced editor. Thanks! Message was edited by: Martin Kojtal

Re: Unhandled Interrupt

c0170 — Mon, 01 Apr 2013 10:27:41 GMT

Hello netra,

I am wondering about your intention. Could you please explain us why would you restart the task which causes an unhandled interrupt?

Regards,

0xc0170

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