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Athira Rajeev d3c38d8549 powerpc/perf: Invoke per-CPU variable access with disabled interrupts

commit f66de7ac4849eb42a7b18e26b8ee49e08130fd27 upstream.

The power_pmu_event_init() callback access per-cpu variable
(cpu_hw_events) to check for event constraints and Branch Stack
(BHRB). Current usage is to disable preemption when accessing the
per-cpu variable, but this does not prevent timer callback from
interrupting event_init. Fix this by using 'local_irq_save/restore'
to make sure the code path is invoked with disabled interrupts.

This change is tested in mambo simulator to ensure that, if a timer
interrupt comes in during the per-cpu access in event_init, it will be
soft masked and replayed later. For testing purpose, introduced a
udelay() in power_pmu_event_init() to make sure a timer interrupt arrives
while in per-cpu variable access code between local_irq_save/resore.
As expected the timer interrupt was replayed later during local_irq_restore
called from power_pmu_event_init. This was confirmed by adding
breakpoint in mambo and checking the backtrace when timer_interrupt
was hit.

Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1606814880-1720-1-git-send-email-atrajeev@linux.vnet.ibm.com
Signed-off-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2021-09-03 10:09:29 +02:00

alpha

alpha: Send stop IPI to send to online CPUs

2021-08-12 13:22:20 +02:00

arc

ARC: Fix CONFIG_STACKDEPOT

2021-09-03 10:09:21 +02:00

arm

ARM: dts: nomadik: Fix up interrupt controller node names

2021-08-26 08:35:38 -04:00

arm64

arm64: dts: qcom: msm8992-bullhead: Remove PSCI