Re: [PATCH 11/14] vdso/vsyscall: Update auxiliary clock data in the datapage

[Thomas Gleixner <tglx@linutronix.de>]

On Mon, Jul 07 2025 at 13:34, Arnd Bergmann wrote:
> On Mon, Jul 7, 2025, at 08:57, Thomas Gleixner wrote:
>> On Tue, Jul 01 2025 at 10:58, Thomas Weißschuh wrote:
>>>  
>>> +#if defined(CONFIG_GENERIC_TIME_VSYSCALL) && defined(CONFIG_GENERIC_GETTIMEOFDAY) && \
>>> +	defined(CONFIG_POSIX_AUX_CLOCKS)
>>
>> CONFIG_GENERIC_GETTIMEOFDAY requires CONFIG_GENERIC_TIME_VSYSCALL, but
>> that's not expressed anywhere. This stuff has grown too many config
>> options over time:
>>
>> GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO, GENERIC_VDSO_DATA_STORE
>>
>> All architectures except SPARC64 use the generic code and the generic
>> VDSO data store implementation. That config maze wants to be
>> consolidated.
>
> Would it help to replace the custom sparc64 vdso with the
> thing that parisc does and call the fallback directly?

Definitely.

> I doubt anyone still cares about the clock_gettime() performance
> on sparc64, and removing it would remove all those special cases:
>
>  arch/sparc/Kconfig                  |   1 -
>  arch/sparc/include/asm/vvar.h       |  75 --------
>  arch/sparc/kernel/Makefile          |   1 -
>  arch/sparc/kernel/vdso.c            |  69 --------
>  arch/sparc/vdso/Makefile            |   2 +-
>  arch/sparc/vdso/vclock_gettime.c    | 340 +++---------------------------------
>  arch/sparc/vdso/vdso.lds.S          |   2 -
>  arch/sparc/vdso/vdso32/vdso32.lds.S |   3 +-
>  arch/sparc/vdso/vma.c               | 265 +---------------------------
>  9 files changed, 28 insertions(+), 730 deletions(-)

That's definitely an argument :)

> (the added lines here also fix the missing clock_gettime64,
> which was equally blocked on the sparc64 oddities)

I'm all for it.

Can you post a patch to that effect?

Thanks,

        tglx