[PATCH 1/4] Minor conditionals to enable building Scheduler Simulator on GNU/Linux

[Joel Sherrill]

On 5/28/2014 2:24 PM, Gedare Bloom wrote:
> On Wed, May 28, 2014 at 2:49 PM, Joel Sherrill
> <joel.sherrill at oarcorp.com> wrote:
>> On 5/28/2014 10:22 AM, Gedare Bloom wrote:
>>> On Wed, May 28, 2014 at 11:05 AM, Joel Sherrill
>>> <joel.sherrill at oarcorp.com> wrote:
>>>> On 5/28/2014 7:39 AM, Gedare Bloom wrote:
>>>>> On Wed, May 28, 2014 at 5:00 AM, Sebastian Huber
>>>>> <sebastian.huber at embedded-brains.de> wrote:
>>>>>> On 2014-05-28 00:16, Joel Sherrill wrote:
>>>>>>> - rtems/score/threadimpl.h: _Thread_Start_multitasking does return
>>>>>>>    on Scheduler Simulator. Initializing RTEMS returns to the command
>>>>>>>    interpreter.
>>>>>>>
>>>>>>> - rtems/score/smpimpl.h: _SMP_Start_multitasking_on_secondary_processor()
>>>>>>>    is not applicable on the Scheduler Simulator and the no return
>>>>>>> attribute
>>>>>>>    gives a warning.
>>>>>>>
>>>>>>> - rtems/score/assert.h: Scheduler Simulator uses glibc assert.h on
>>>>>>> GNU/Linux.
>>>>>>>    This will likely need to be adjusted more for other host compilers and
>>>>>>>    C libraries
>>>>>>>
>>>>>>> - threadrestart.c: Disable assert on Scheduler Simulator. Restarting self
>>>>>>>    returns to the command interpreter.
>>>>>> I would define RTEMS_COMPILER_NO_RETURN_ATTRIBUTE and _Assert() to nothing
>>>>>> in case RTEMS_SCHEDSIM is defined.  Do you really need this debugging stuff
>>>>>> for the scheduler simulator?  I don't think we should propagate oddities of
>>>>>> the scheduler simulator throughout the code base.
>>>>>>
>>>>> Yes, this was my initial reaction as well. Probably at least you could
>>>>> make Assert_Not_reached() a nop, or write a wrapper for assert that
>>>>> depends on schedsim. Can schedsim work more like a real target for
>>>>> this case of not returning? I guess usually the system ends up in a
>>>>> fatal or halt state? Maybe you can interpose on that state to return
>>>>> to the command interpreter.
>>>> Schedsim does not really context switch so the paths that assume a task
>>>> switches
>>>> out and never returns are reachable paths. It is logically a single
>>>> thread of control
>>>> with the underlying RTEMS code thinking that a thread is "executing" on
>>>> the various
>>>> cores. When a thread blocks, control returns to the script with a new
>>>> executing
>>>> thread. In an SMP configuration, the scripts can also change CPU focus
>>>> and execute
>>>> commands in the context of  the executing thread on that core.
>>>>
>>>> I can live with disabling the noreturn checks and turning off that
>>>> warning. I think
>>>> that will eliminate the first two of the four spots touched above.
>>>>
>>>> But I don't want to disable the asserts. Right now, we can run with
>>>> --enable-rtems-debug
>>>> and not get any asserts. The consistency checks are really handy and
>>>> they found
>>>> bugs in the Affinity Scheduler. So I really do not want to disable
>>>> them.  So killing
>>>> assertions is undesirable.
>>>>
>>>> I could try to move all of the alternative assert logic under an
>>>> RTEMS_SCHEDSIM.
>>>> That would make it clearer what it is for and harder to trip.
>>>>
>>>> For know, making Assert_Not_reached() nothing on Schedsim would be
>>>> acceptable
>>>> for the _Thread_Restart() assertion.
>>>>
>>>> I think this would restrict the patch to the rtems assert.h. Is that
>>>> acceptable?
>>>>
>>> Yes, that would be better.
>> I can't turn off the no return warning via the command line. That
>> touches basedefs.h.
>>
>> So basedefs.h and assert.h are the reduced set of files touched.
>>
>> New version attached.
> You changed to using #if instead of #if defined. I think you want it
> with the ifdef.
How about this one?  I tried to stay consistent in style with what was
already in the file.

But defined(X) or defined( X ) in the rules?
> -Gedare

-- 
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

-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-Minor-conditionals-to-enable-building-Scheduler-Simu.patch
Type: text/x-patch
Size: 2727 bytes
Desc: not available
URL: <http://lists.rtems.org/pipermail/devel/attachments/20140529/ebebad93/attachment-0001.bin>