Re: [PATCH v2 1/2] Refactor sigcontextinfo.h

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

On 15/08/2019 11:36, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>> On 15/08/2019 10:53, Florian Weimer wrote:
>>> * Adhemerval Zanella:
>>>
>>>>> So I strongly urge you to add a test like the one below.  I can commit
>>>>> it separately after your patch.  I still need to verify that it builds
>>>>> on all architectures.
>>>>
>>>> I will integrate your tests if you are ok with that, however it requires some
>>>> changes.
>>>
>>> Thanks.  What kind of changes?
>>>
>>> SA_SIGINFO is missing from sa_flags.  I've already fixed that.
>>>
>>>> I will double check it on some different architectures also.
>>>
>>> It works on aarch64, i386, x86-64, s390, s390x, ppc64le.  I planned to
>>> test ppc and ppc64 as well, but could not get a Beaker machine yet.
>>
>> I can check on alpha, hppa, sh4, arm, m68k, sparc, and ia64. Both ia64 and
>> sparc does not pass a ucontext_t as third argument, so these are the ones
>> I would like to double-check.
> 
> Sounds good.  The tests (with the SA_SIGINFO fix applied) builds
> everywhere using build-many-glibcs.py.

The check call backtrace with in a signal handle, so it needs to be built with
-fasynchronous-unwind-tables (testing on sparc showed that without this option
it can't get a full stacktrace, I think some ABIs have the same issue).

Another issue is ia64 trick to try to find the instruction in bundle by 
multiplying the ri number by 4 and adding on sc_ip makes the resulting
value not comparable to the one got from backtrace.  I see this is best
effort, since not all instructions have the same length (although all
bundle are 128-bits).  I think ia64 libdebug and profiling can live
without this hack, and it simplifies the bz#12683 fix as well.

I will resend the patch with this changes and the test included.