ACPI CPUs aren't associated with a PMU until they have been put
online. This means that we potentially have to update a PMU
definition the first time a CPU is hot added to the machine.

Signed-off-by: Jeremy Linton <redacted>
---
 drivers/perf/arm_pmu.c       | 38 ++++++++++++++++++++++++++++++++++++--
 include/linux/perf/arm_pmu.h |  4 ++++
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index fa40294..4abb2fe 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c

@@ -711,6 +711,30 @@ static int cpu_pmu_request_irq(struct arm_pmu *cpu_pmu, irq_handler_t handler)
 	return 0;
 }
 
+static DEFINE_SPINLOCK(arm_pmu_resource_lock);