On 06/06/2012 05:21 PM, Philippe Gerum wrote:
> On 06/06/2012 05:15 PM, Gilles Chanteperdrix wrote:
>> On 06/06/2012 05:03 PM, Philippe Gerum wrote:
>>> On 06/06/2012 04:27 PM, Gilles Chanteperdrix wrote:
>>>> On 06/06/2012 04:02 PM, Gilles Chanteperdrix wrote:
>>>>> On 06/06/2012 03:55 PM, Gilles Chanteperdrix wrote:
>>>>>> On 06/06/2012 03:53 PM, Philippe Gerum wrote:
>>>>>>> On 06/06/2012 03:41 PM, Gilles Chanteperdrix wrote:
>>>>>>>> On 06/06/2012 03:25 PM, Philippe Gerum wrote:
>>>>>>>>> On 06/06/2012 03:18 PM, Gilles Chanteperdrix wrote:
>>>>>>>>>> On 06/06/2012 02:28 PM, Philippe Gerum wrote:
>>>>>>>>>>> On 06/06/2012 11:48 AM, Philippe Gerum wrote:
>>>>>>>>>>>> On 06/06/2012 11:18 AM, ali hagigat wrote:
>>>>>>>>>>>>> Much appreciate for the reply, Mr. Gerum. Here is the result of
>>>>>>>>>>>>> ldd
>>>>>>>>>>>>> command:
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> http://www.xenomai.org/pipermail/xenomai-help/2011-12/msg00012.html
>>>>>>>>>>>
>>>>>>>>>>> Alternatively, this patch may work as well (not tested, but this
>>>>>>>>>>> looks like a former issue we had with aggressive optimizers):
>>>>>>>>>>>
>>>>>>>>>>> diff --git a/src/skins/posix/init.c b/src/skins/posix/init.c
>>>>>>>>>>> index 7a338a0..9c7849e 100644
>>>>>>>>>>> --- a/src/skins/posix/init.c
>>>>>>>>>>> +++ b/src/skins/posix/init.c
>>>>>>>>>>> @@ -43,6 +43,7 @@ void pse51_clock_init(int);
>>>>>>>>>>> static __attribute__ ((constructor))
>>>>>>>>>>> void __init_posix_interface(void)
>>>>>>>>>>> {
>>>>>>>>>>> + volatile pthread_t tid = pthread_self();
>>>>>>>>>>> #ifndef CONFIG_XENO_LIBS_DLOPEN
>>>>>>>>>>> struct sched_param parm;
>>>>>>>>>>> int policy;
>>>>>>>>>>> @@ -80,14 +81,14 @@ void __init_posix_interface(void)
>>>>>>>>>>>
>>>>>>>>>>> /* Don't use auto-shadowing if we are likely invoked
>>>>>>>>>>> from dlopen. */
>>>>>>>>>>> #ifndef CONFIG_XENO_LIBS_DLOPEN
>>>>>>>>>>> - err =
>>>>>>>>>>> __real_pthread_getschedparam(pthread_self(),&policy,&parm);
>>>>>>>>>>> + err = __real_pthread_getschedparam(tid,&policy,&parm);
>>>>>>>>>>> if (err) {
>>>>>>>>>>> fprintf(stderr, "Xenomai Posix skin init: "
>>>>>>>>>>> "pthread_getschedparam: %s\n",
>>>>>>>>>>> strerror(err));
>>>>>>>>>>> exit(EXIT_FAILURE);
>>>>>>>>>>> }
>>>>>>>>>>>
>>>>>>>>>>> - err = __wrap_pthread_setschedparam(pthread_self(),
>>>>>>>>>>> policy,&parm);
>>>>>>>>>>> + err = __wrap_pthread_setschedparam(tid, policy,&parm);
>>>>>>>>>>> if (err) {
>>>>>>>>>>> fprintf(stderr, "Xenomai Posix skin init: "
>>>>>>>>>>> "pthread_setschedparam: %s\n",
>>>>>>>>>>> strerror(err));
>>>>>>>>>>
>>>>>>>>>> There should not be any issue here, as the pthread_self() is passed
>>>>>>>>>> as
>>>>>>>>>> an argument to the called functions, the syscall is not inlined
>>>>>>>>>> directly.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Did you get any disassembly of the faulty code when suggesting
>>>>>>>>> -fno-omit-frame-pointer last time you did?
>>>>>>>>>
>>>>>>>> No, but I had experienced the problem first hand.
>>>>>>>>
>>>>>>>
>>>>>>> It would be interesting to know why we have to force a frame pointer in
>>>>>>> there. I'm not comfortable with voodoo fixing, that bug might bite later
>>>>>>> on as gcc's optimizer is unlikely to become less aggressive over time.
>>>>>>>
>>>>>> Ah this, I know. I have posted a mail where I explained the problem. I
>>>>>> am a bit in a short schedule here, will post the link tonight.
>>>>>>
>>>>> http://xenomai.org/pipermail/xenomai-core/2011-08/msg00029.html
>>>>>
>>>>
>>>> In the mails following this one, I found how to fix the assembly to work
>>>> in the omit-frame-pointer case. The real problem is that, at compilation
>>>> time, we have no command-line #defined variable telling us whether
>>>> compiling with frame pointers enabled. And it does not seem easy to
>>>> write a configure test script, which tests whether frame pointers are
>>>> enabled or not.
>>>>
>>>
>>> I'd suggest that at some point, we move all the syscall trampolines out
>>> of line, and specifically build the resulting file forcing
>>> -fno-omit-frame-pointer. Such inlining will always be fragile until we
>>> actually control the way that compilation unit is built, regardless of
>>> the general settings for CFLAGS.
>>>
>> In the current 2.6 repository, we force -fno-omit-frame-pointer on x86_32.
>>
>
> Yes, but that is crappy. The point is that we don't want to force this
> for all userland bits. We'd only need this for syscall trampolines.
>
We currently have different flags for compiling xenomai than for passing
to the applications (via xeno-config). The problem is that I am not sure
it will not break for instance calling "backtrace" in gdb when breaking
inside a xenomai function.
--
Gilles.
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