Christophe Leroy <christophe.le...@csgroup.eu> writes:
> Quoting Michael Ellerman <m...@ellerman.id.au>:
>
>> Christophe Leroy <christophe.le...@csgroup.eu> writes:
>>> Le 03/11/2020 à 19:13, Christophe Leroy a écrit :
>>>> Le 23/10/2020 à 15:24, Michael Ellerman a écrit :
>>>>> Christophe Leroy <christophe.le...@csgroup.eu> writes:
>>>>>> Le 24/09/2020 à 15:17, Christophe Leroy a écrit :
>>>>>>> Le 17/09/2020 à 14:33, Michael Ellerman a écrit :
>>>>>>>> Christophe Leroy <christophe.le...@csgroup.eu> writes:
>>>>>>>>>
>>>>>>>>> What is the status with the generic C vdso merge ?
>>>>>>>>> In some mail, you mentionned having difficulties getting it working on
>>>>>>>>> ppc64, any progress ? What's the problem ? Can I help ?
>>>>>>>>
>>>>>>>> Yeah sorry I was hoping to get time to work on it but haven't been able
>>>>>>>> to.
>>>>>>>>
>>>>>>>> It's causing crashes on ppc64 ie. big endian.
>>>>> ...
>>>>>>>
>>>>>>> Can you tell what defconfig you are using ? I have been able to
>>>>>>> setup a full glibc PPC64 cross
>>>>>>> compilation chain and been able to test it under QEMU with
>>>>>>> success, using Nathan's vdsotest tool.
>>>>>>
>>>>>> What config are you using ?
>>>>>
>>>>> ppc64_defconfig + guest.config
>>>>>
>>>>> Or pseries_defconfig.
>>>>>
>>>>> I'm using Ubuntu GCC 9.3.0 mostly, but it happens with other
>>>>> toolchains too.
>>>>>
>>>>> At a minimum we're seeing relocations in the output, which is a problem:
>>>>>
>>>>> $ readelf -r build\~/arch/powerpc/kernel/vdso64/vdso64.so
>>>>> Relocation section '.rela.dyn' at offset 0x12a8 contains 8 entries:
>>>>> Offset Info Type Sym. Value
>>>>> Sym. Name + Addend
>>>>> 000000001368 000000000016 R_PPC64_RELATIVE 7c0
>>>>> 000000001370 000000000016 R_PPC64_RELATIVE 9300
>>>>> 000000001380 000000000016 R_PPC64_RELATIVE 970
>>>>> 000000001388 000000000016 R_PPC64_RELATIVE 9300
>>>>> 000000001398 000000000016 R_PPC64_RELATIVE a90
>>>>> 0000000013a0 000000000016 R_PPC64_RELATIVE 9300
>>>>> 0000000013b0 000000000016 R_PPC64_RELATIVE b20
>>>>> 0000000013b8 000000000016 R_PPC64_RELATIVE 9300
>>>>
>>>> Looks like it's due to the OPD and relation between the function()
>>>> and .function()
>>>>
>>>> By using DOTSYM() in the 'bl' call, that's directly the dot
>>>> function which is called and the OPD is
>>>> not used anymore, it can get dropped.
>>>>
>>>> Now I get .rela.dyn full of 0, don't know if we should drop it explicitely.
>>>
>>> What is the status now with latest version of CVDSO ? I saw you had
>>> it in next-test for some time,
>>> it is not there anymore today.
>>
>> Still having some trouble with the compat VDSO.
>>
>> eg:
>>
>> $ ./vdsotest clock-gettime-monotonic verify
>> timestamp obtained from kernel predates timestamp
>> previously obtained from libc/vDSO:
>> [1346, 821441653] (vDSO)
>> [570, 769440040] (kernel)
>>
>>
>> And similar for all clocks except the coarse ones.
>>
>
> Ok, I managed to get the same with QEMU. Looking at the binary, I only
> see an mftb instead of the mftbu/mftb/mftbu triplet.
>
> Fix below. Can you carry it, or do you prefer a full patch from me ?
> The easiest would be either to squash it into [v13,4/8]
> ("powerpc/time: Move timebase functions into new asm/timebase.h"), or
> to add it between patch 4 and 5 ?
I can squash it in.
cheers
