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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: Marc Zyngier <maz@kernel.org>
Reviewed-by: Maulik Shah <quic_mkshah@quicinc.com>
Link: https://lore.kernel.org/r/20220224101226.88373-5-maz@kernel.org
This commit is contained in:
Marc Zyngier 2022-02-24 10:12:25 +00:00
parent d494d088ac
commit a6aca2f460
1 changed files with 3 additions and 2 deletions
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5
drivers/irqchip/qcom-pdc.c
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@ -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)