| Message ID | 20220224101226.88373-5-maz@kernel.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | irqchip/qcom-pdc: Assorted cleanups and fixes | expand |
Hi, On 2/24/2022 3:42 PM, Marc Zyngier wrote: > 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> Thanks, Maulik > --- > drivers/irqchip/qcom-pdc.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > >
diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c index 837ca6998f6a..0cd20ddfae2a 100644 --- a/drivers/irqchip/qcom-pdc.c +++ b/drivers/irqchip/qcom-pdc.c @@ -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)
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> --- drivers/irqchip/qcom-pdc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)