diff options
| author | Daniel Thompson <daniel.thompson@linaro.org> | 2015-01-21 14:27:28 +0000 |
|---|---|---|
| committer | Daniel Thompson <daniel.thompson@linaro.org> | 2015-01-21 14:59:33 +0000 |
| commit | 6cb22bb10beffe606d360878dfea0c2dab6e01c8 (patch) | |
| tree | db6cf8068fc3a0f168614c9508c5d5a4a3e2c17e | |
| parent | f913babcc85d4c87d5c556d3272b613a0145cff3 (diff) | |
arm: perf: Make v7 support FIQ-safe
armv7pmu_disable_event() is called during irq handling. If irq handling
switches over to fiq then the spin locks in this function risk deadlock.
Both armv7_pmnc_disable_counter() and armv7_pmnc_disable_intens() are
unconditional co-processor writes. I haven't yet come up with an
schedule where other users of pmu_lock would break if interleaved with
these calls so I have simply removed them.
The other change required us to avoid calling irq_work_run() when run
from a FIQ handler. The pended work will either be dispatched by the
irq work IPI or by a timer handler.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
| -rw-r--r-- | arch/arm/kernel/perf_event_v7.c | 11 |
1 files changed, 2 insertions, 9 deletions
diff --git a/arch/arm/kernel/perf_event_v7.c b/arch/arm/kernel/perf_event_v7.c index 8993770c47de..08f426486d3e 100644 --- a/arch/arm/kernel/perf_event_v7.c +++ b/arch/arm/kernel/perf_event_v7.c @@ -744,7 +744,6 @@ static void armv7pmu_enable_event(struct perf_event *event) static void armv7pmu_disable_event(struct perf_event *event) { - unsigned long flags; struct hw_perf_event *hwc = &event->hw; struct arm_pmu *cpu_pmu = to_arm_pmu(event->pmu); struct pmu_hw_events *events = this_cpu_ptr(cpu_pmu->hw_events); @@ -757,11 +756,6 @@ static void armv7pmu_disable_event(struct perf_event *event) } /* - * Disable counter and interrupt - */ - raw_spin_lock_irqsave(&events->pmu_lock, flags); - - /* * Disable counter */ armv7_pmnc_disable_counter(idx); @@ -770,8 +764,6 @@ static void armv7pmu_disable_event(struct perf_event *event) * Disable interrupt for this counter */ armv7_pmnc_disable_intens(idx); - - raw_spin_unlock_irqrestore(&events->pmu_lock, flags); } static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev) @@ -831,7 +823,8 @@ static irqreturn_t armv7pmu_handle_irq(int irq_num, void *dev) * 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; } |