Commit a6aca2f4 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

irqchip/qcom-pdc: Fix broken locking 



pdc_enable_intr() serves as a primitive to qcom_pdc_gic_{en,dis}able,
and has a raw spinlock for mutual exclusion, which is uses with
interruptible primitives.

This means that this critical section can itself be interrupted.
Should the interrupt also be a PDC interrupt, and the endpoint driver
perform an irq_disable() on that interrupt, we end-up in a deadlock.

Fix this by using the irqsave/irqrestore variants of the locking
primitives.

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarMaulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20220224101226.88373-5-maz@kernel.org
parent d494d088

drivers/irqchip/qcom-pdc.c

+3 −2
Original line number Diff line number Diff line
@@ -55,17 +55,18 @@ static u32 pdc_reg_read(int reg, u32 i) 
static void pdc_enable_intr(struct irq_data *d, bool on)

{

	int pin_out = d->hwirq;

	unsigned long flags;

	u32 index, mask;

	u32 enable;



	index = pin_out / 32;

	mask = pin_out % 32;



	raw_spin_lock(&pdc_lock);

	raw_spin_lock_irqsave(&pdc_lock, flags);

	enable = pdc_reg_read(IRQ_ENABLE_BANK, index);

	enable = on ? ENABLE_INTR(enable, mask) : CLEAR_INTR(enable, mask);

	pdc_reg_write(IRQ_ENABLE_BANK, index, enable);

	raw_spin_unlock(&pdc_lock);

	raw_spin_unlock_irqrestore(&pdc_lock, flags);

}



static void qcom_pdc_gic_disable(struct irq_data *d)