On most ARM systems the per-cpu clockevents are truly per-cpu in
the sense that they can't be controlled on any other CPU besides
the CPU that they interrupt. If one of these clockevents were to
become a broadcast source we will run into a lot of trouble
because the broadcast source is enabled on the first CPU to go
into deep idle (if that CPU suffers from FEAT_C3_STOP) and that
could be a different CPU than what the clockevent is interrupting
(or even worse the CPU that the clockevent interrupts could be
offline).
Theoretically it's possible to support per-cpu clockevents as the
broadcast source but so far we haven't needed this and supporting
it is rather complicated. Let's just deny the possibility for now
until this becomes a reality (let's hope it never does!).
Reported-by: Sören Brinkmann <soren.brinkm...@xilinx.com>
Signed-off-by: Stephen Boyd <sb...@codeaurora.org>
---
kernel/time/tick-broadcast.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 218bcb5..d3539e5 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -77,6 +77,9 @@ static bool tick_check_broadcast_device(struct
clock_event_device *curdev,
!(newdev->features & CLOCK_EVT_FEAT_ONESHOT))
return false;
+ if (cpumask_equal(newdev->cpumask, cpumask_of(smp_processor_id())))
+ return false;
+
return !curdev || newdev->rating > curdev->rating;
}
--
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