[PATCH v2 0/5] ARM: Remaining PREEMPT_RT bits

[Arnd Bergmann]

On Mon, Nov 3, 2025, at 11:15, Sebastian Andrzej Siewior wrote:
> this is the last batch I have to enable PREEMPT_RT on the ARM
> architecture.
> Last time I posted them there was some discussion about making the
> branch predictor hardening worse. I redid it hoping it improved now and
> does not make it worse.
>
> v1…v2: https://lore.kernel.org/all/20251029155918.503060-1-bigeasy@linutronix.de
>   - Allow to enable jump-labels on UP. The UP build does not involve
>     stop_machine(). Reworked by Arnd.
>
>   - Instead of forbidding HAVE_GUP_FAST with HIGHPTE enabled just
>     disable HIGHPTE on PREEMPT_RT. As Arnd explained, HIGHPTE is rarely
>     needed.
>
>   - Don't let ARCH_SUPPORTS_RT depend on HAVE_POSIX_CPU_TIMERS_TASK_WORK
>     which in turn depends on !KVM. Since KVM has been removed from ARM
>     it is sufficient to unconditionally allow ARCH_SUPPORTS_RT. Noted
>     by Arnd.

Whole series

Reviewed-by: Arnd Bergmann <arnd at arndb.de>

Looks all good to me. The first two patches may clash with
the work on generic entry that I think Linus Walleij (added to
Cc) is in the process of rebasing, but I think that is fine:
hopefully the special case that you  adding here will just go
away after Linus' patches, so everything should be fine
regardless of which gets merged first.

Linus, can you have a look and confirm?

      Arnd