From e9dc5b3f09a3bbdeead8ddbcd159fedb8e43f51d Mon Sep 17 00:00:00 2001
From: Julien Thierry <julien.thierry@arm.com>
Date: Wed, 20 Mar 2019 14:35:19 +0800
Subject: [PATCH] arm64: perf: Do not call irq_work_run in NMI context

hulk inclusion
category: feature
bugzilla: 12804
CVE: NA

-------------------------------------------------

Function irq_work_run is not NMI safe and should not be called from NMI
context.

When PMU interrupt is an NMI do not call irq_work_run. Instead rely on the
IRQ work IPI to run the irq_work queue once NMI/IRQ contexts have been
exited.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 arch/arm64/kernel/perf_event.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index ec74a7c7190d..c6fe36f5a9f5 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -895,7 +895,8 @@ static irqreturn_t armv8pmu_handle_irq(struct arm_pmu *cpu_pmu)
 	 * platforms that can have the PMU interrupts raised as an NMI, this
 	 * will not work.
 	 */
-	irq_work_run();
+	if (!in_nmi())
+		irq_work_run();
 
 	return IRQ_HANDLED;
 }
-- 
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