Debugging basic BSP tasking functionality

Thu Apr 18 13:56:17 UTC 2013

Hi,

> Now as Sebastian says, the handler might be mis-registered as raw
> not OS interrupt. And the BSP may have been mechanically converted
> to the new shared PIC interrupt code used by many BSPs but not
> tested.

Is there an example of a BSP registering a tick interrupt that i can
examine/copy ? this morning attempts to change the use of
rtems_interrupt_handler_install() has just resulted in unhandled IRQ
exceptions.

On 17 April 2013 16:01, Joel Sherrill <joel.sherrill at oarcorp.com> wrote:

>  On 4/17/2013 9:47 AM, Matthew J Fletcher wrote:
>
>  >If you put an explicit call to rtems_stack_checker_is_blown() in Init()
> at
> >various points, does it think things are OK?
>
>  I put in a few and even the last one before the Init() task deletes
> itself is ok.
>
>
>   OK.
>
>  >Just to be clear.. is this with the rtl22xx or rtl22xx_t BSP? The
> non-thumb version
> >uses -mapcs-frame which no other BSP uses. That makes me wonder.
>
>  rtl22xx_t 'Thumb', -mapcs-frame is passed on the gcc command line.
>
>   If this is the BSP you are using, take it off and try again. This is
> the only BSP
> using this option. Sebastian can probably comment on the other arguments.
>
>
> >Not with RTEMS. When you enter/exit an ISR, you go through some
> >code which saves the proper registers, probably switches you to
> >a dedicated stack, and does the OS stuff needed so it will do
> >any needed dispatching at the end of the interrupt.
>
>  Is this shared between BSPs ? i tried to look for this and failed.
>
>
>   It is absolutely shared. The BSP has to provide some glue code but
> between libbsp/shared, libbsp/<ARCH>/shared, and the appropriate
> libcpu directory, you will find the code.
>
> Look for shared and libcpu in the Makefile.am.
>
> Now as Sebastian says, the handler might be mis-registered as raw
> not OS interrupt. And the BSP may have been mechanically converted
> to the new shared PIC interrupt code used by many BSPs but not
> tested.
>
>
>
> On 17 April 2013 15:34, Joel Sherrill <joel.sherrill at oarcorp.com> wrote:
>
>>  On 4/17/2013 9:04 AM, Matthew J Fletcher wrote:
>>
>>  Hi,
>>
>>  Yes it the stack pointer out of range, because the current stack pointer
>> returned by GCC _builtin_frame_XX in the IDLE thread looks like its
>> actually that from the Init() thread.
>>
>>   You are completely in C code when this happens. There has been assembly
>> to switch to the task initially (e.g. into _Thread_Handler) and if an
>> interrupt
>> occurred.
>>
>> If you put an explicit call to rtems_stack_checker_is_blown() in Init() at
>> various points, does it think things are OK?
>>
>> It is easy for the stack not to be initialized to match gcc or gdb's
>> expectation
>> of how it ends.
>>
>> Just to be clear.. is this with the rtl22xx or rtl22xx_t BSP? The
>> non-thumb version
>> uses -mapcs-frame which no other BSP uses. That makes me wonder.
>>
>>  Thinking this through,my target is Thumb, so the C interrupt handler
>> should be in a arm file with -mthumb-interwork set on the compile line.
>>
>>  I guess GCC can not auto-magicly know what particular functions are
>> interrupts, so should there be some entry/exit functions to save/restore
>> the stack, etc, like these...
>>
>>
>> http://www.procyonengineering.com/embedded/arm/armlib/docs/html/group__processor__lpc2000.html
>>
>> ISR_ENTRY / ISR_EXIT
>>
>>
>>   Not with RTEMS. When you enter/exit an ISR, you go through some
>> code which saves the proper registers, probably switches you to
>> a dedicated stack, and does the OS stuff needed so it will do
>> any needed dispatching at the end of the interrupt.
>>
>> --joel
>>
>>
>>
>>
>>
>> On 17 April 2013 13:40, Sebastian Huber <
>> sebastian.huber at embedded-brains.de> wrote:
>>
>>> On 04/17/2013 02:27 PM, Matthew J Fletcher wrote:
>>>
>>>>  >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.
>>>>
>>>> Yes it is, Init() stack area is 0x814d1a70 -> 0x814d2a74 (4100 bytes).
>>>> So it
>>>> looks like the stack pointer is not getting adjusted correctly when task
>>>> switching into a new thread ? as the rtems_idle task is using the
>>>> Init() stack
>>>> pointer.
>>>>
>>>
>>>  Now I am a bit confused.  What check goes wrong in
>>>
>>>
>>> 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
>>>
>>>  ?
>>>
>>> In case the stack pointer is out of range, then I guess that the
>>> interrupt exception processing is broken.  It is hard to know what happens
>>> without an actual target.
>>>
>>>
>>>
>>>>  > nm your-app.exe | grep 'bsp_\(section\|stack\)' | sort
>>>>
>>>> No matches.
>>>>
>>>
>>>  Ok, 4.10 uses the old linker command files.  These symbols are only
>>> available in 4.11.
>>>
>>>
>>> --
>>> Sebastian Huber, embedded brains GmbH
>>>
>>> Address : Dornierstr. 4, D-82178 Puchheim, Germany
>>> Phone   : +49 89 189 47 41-16 <%2B49%2089%20189%2047%2041-16>
>>> Fax     : +49 89 189 47 41-09 <%2B49%2089%20189%2047%2041-09>
>>> E-Mail  : sebastian.huber at embedded-brains.de
>>> PGP     : Public key available on request.
>>>
>>> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
>>>
>>
>>
>>
>> --
>>
>> regards
>> ---
>> Matthew J Fletcher
>>
>>
>>
>>   --
>> Joel Sherrill, Ph.D.             Director of Research & Development joel.sherrill at OARcorp.com        On-Line Applications Research
>> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
>> Support Available                (256) 722-9985
>>
>>
>
>
> --
>
> regards
> ---
> Matthew J Fletcher
>
>
>
> --
> Joel Sherrill, Ph.D.             Director of Research & Development joel.sherrill at OARcorp.com        On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
> Support Available                (256) 722-9985
>
>

-- 

regards
---
Matthew J Fletcher
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