Re: [PATCH 2/7] vDSO: Make clockmode constants available without CONFIG_GENERIC_GETTIMEOFDAY

[Thomas Gleixner]

On Thu, Jul 09 2026 at 13:32, Thomas Weißschuh wrote:
> diff --git a/include/asm-generic/Kbuild b/include/asm-generic/Kbuild
> index 15df9dcb42a5..2bc00c67dc54 100644
> --- a/include/asm-generic/Kbuild
> +++ b/include/asm-generic/Kbuild
> @@ -62,6 +62,7 @@ mandatory-y += topology.h
>  mandatory-y += trace_clock.h
>  mandatory-y += uaccess.h
>  mandatory-y += unwind_user.h
> +mandatory-y += vdso/clocksource.h
>  mandatory-y += vermagic.h
>  mandatory-y += vga.h
>  mandatory-y += video.h
> diff --git a/include/asm-generic/vdso/clocksource.h b/include/asm-generic/vdso/clocksource.h
> new file mode 100644
> index 000000000000..e69de29bb2d1
> diff --git a/include/vdso/clocksource.h b/include/vdso/clocksource.h
> index c682e7c60273..63ee8c4ea15c 100644
> --- a/include/vdso/clocksource.h
> +++ b/include/vdso/clocksource.h
> @@ -4,9 +4,12 @@
>  
>  #include <vdso/limits.h>
>  
> -#ifdef CONFIG_GENERIC_GETTIMEOFDAY
>  #include <asm/vdso/clocksource.h>
> -#endif /* CONFIG_GENERIC_GETTIMEOFDAY */
> +
> +#if !IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY) && defined(VDSO_ARCH_CLOCKMODES)
> +/* Unlinkable dummy stubs */
> +extern int VDSO_ARCH_CLOCKMODES;
> +#endif

I'm utterly confused by this. What's this unlinkable stub for?

The only usage of VDSO_ARCH_CLOCKMODES is in enum vdso_clock_modes where
it is guarded with CONFIG_GENERIC_GETTIMEOFDAY.

And your change log says:

> Provide unlinkable dummy definitions. These can be used with
> IS_ENABLED(CONFIG_GENERIC_GETTIMEOFDAY).

which is even more confusing because that's related to the actual
architecture specific defines and not to VDSO_ARCH_CLOCKMODES.

None of this makes sense to me.

Thanks,

        tglx