Bugzilla: http://bugzilla.redhat.com/2019472



commit a8b76910e465d718effce0cad306a21fa4f3526b
Author: Valentin Schneider <valentin.schneider@arm.com>
Date:   Wed Nov 10 20:24:44 2021 +0000

    preempt: Restore preemption model selection configs

    Commit c597bfddc9e9 ("sched: Provide Kconfig support for default dynamic
    preempt mode") changed the selectable config names for the preemption
    model. This means a config file must now select

      CONFIG_PREEMPT_BEHAVIOUR=y

    rather than

      CONFIG_PREEMPT=y

    to get a preemptible kernel. This means all arch config files would need to
    be updated - right now they'll all end up with the default
    CONFIG_PREEMPT_NONE_BEHAVIOUR.

    Rather than touch a good hundred of config files, restore usage of
    CONFIG_PREEMPT{_NONE, _VOLUNTARY}. Make them configure:
    o The build-time preemption model when !PREEMPT_DYNAMIC
    o The default boot-time preemption model when PREEMPT_DYNAMIC

    Add siblings of those configs with the _BUILD suffix to unconditionally
    designate the build-time preemption model (PREEMPT_DYNAMIC is built with
    the "highest" preemption model it supports, aka PREEMPT). Downstream
    configs should by now all be depending / selected by CONFIG_PREEMPTION
    rather than CONFIG_PREEMPT, so only a few sites need patching up.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Marco Elver <elver@google.com>
    Link: https://lore.kernel.org/r/20211110202448.4054153-2-valentin.schneider@arm.com



Signed-off-by: Phil Auld <pauld@redhat.com>