linux-kernel - [PATCH 2/2] bus: arm-cci: Fix use of smp_processor

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Message-Id: <20170904173041.14119-3-marc.zyngier@arm.com>
Date:   Mon,  4 Sep 2017 18:30:41 +0100
From:   Marc Zyngier <marc.zyngier@....com>
To:     Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Pawel Moll <pawel.moll@....com>,
        Mark Rutland <mark.rutland@....com>
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] bus: arm-cci: Fix use of smp_processor_id() in preemptible context

The ARM CCI driver seem to be using smp_processor_id() in a
preemptible context, which is likely to make a DEBUG_PREMPT
kernel scream at boot time.

Turning this into a get_cpu()/put_cpu() should make it behave.

Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
 drivers/bus/arm-cci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
index c49da15d9790..e2873789972a 100644
--- a/drivers/bus/arm-cci.c
+++ b/drivers/bus/arm-cci.c
@@ -1755,7 +1755,8 @@ static int cci_pmu_probe(struct platform_device *pdev)
 	raw_spin_lock_init(&cci_pmu->hw_events.pmu_lock);
 	mutex_init(&cci_pmu->reserve_mutex);
 	atomic_set(&cci_pmu->active_events, 0);
-	cpumask_set_cpu(smp_processor_id(), &cci_pmu->cpus);
+	cpumask_set_cpu(get_cpu(), &cci_pmu->cpus);
+	put_cpu();
 
 	ret = cci_pmu_init(cci_pmu, pdev);
 	if (ret)
-- 
2.11.0