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bus: arm-ccn: fix PMU interrupt flags 

Currently the IRQ core is permitted to make the CCN PMU IRQ handler
threaded, and will allow userspace to change the CPU affinity of the
interrupt behind our back. Both of these could violate our
synchronisation requirements with the core perf code, which relies upon
strict CPU affinity and disabling of interrupts to guarantee mutual
exclusion in some cases.

As with the CPU PMU drivers, we should request the interrupt with
IRQF_NOBALANCING and IRQF_NO_THREAD, to avoid these issues.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Pawel Moll <pawel.moll@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
This commit is contained in:
Mark Rutland 2016-08-11 10:50:41 +01:00 committed by Pawel Moll
parent 3249bce459
commit 0811ef7e2f
1 changed files with 3 additions and 2 deletions
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5
drivers/bus/arm-ccn.c
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@ -1496,8 +1496,9 @@ static int arm_ccn_probe(struct platform_device *pdev)
/* Can set 'disable' bits, so can acknowledge interrupts */
writel(CCN_MN_ERRINT_STATUS__PMU_EVENTS__ENABLE,
ccn->base + CCN_MN_ERRINT_STATUS);
err = devm_request_irq(ccn->dev, irq, arm_ccn_irq_handler, 0,
dev_name(ccn->dev), ccn);
err = devm_request_irq(ccn->dev, irq, arm_ccn_irq_handler,
IRQF_NOBALANCING | IRQF_NO_THREAD,
dev_name(ccn->dev), ccn);
if (err)
return err;