powerpc/preempt: Don't touch the idle task's preempt_count during hotplug
Powerpc currently resets a CPU's idle task preempt_count to 0 before said task starts executing the secondary startup routine (and becomes an idle task proper). This conflicts with commit f1a0a376 ("sched/core: Initialize the idle task with preemption disabled"). which initializes all of the idle tasks' preempt_count to PREEMPT_DISABLED during smp_init(). Note that this was superfluous before said commit, as back then the hotplug machinery would invoke init_idle() via idle_thread_get(), which would have already reset the CPU's idle task's preempt_count to PREEMPT_ENABLED. Get rid of this preempt_count write. Fixes: f1a0a376 ("sched/core: Initialize the idle task with preemption disabled") Reported-by:Bharata B Rao <bharata@linux.ibm.com> Signed-off-by:
Valentin Schneider <valentin.schneider@arm.com> Tested-by:
Guenter Roeck <linux@roeck-us.net> Tested-by:
Bharata B Rao <bharata@linux.ibm.com> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210707183831.2106509-1-valentin.schneider@arm.com
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