irqchip/atmel-aic: Fix potential deadlock in ->xlate()

aic5_irq_domain_xlate() and aic_irq_domain_xlate() take the generic chip
lock without disabling interrupts, which can lead to a deadlock if an
interrupt occurs while the lock is held in one of these functions.

Replace irq_gc_{lock,unlock}() calls by
irq_gc_{lock_irqsave,unlock_irqrestore}() ones to prevent this bug from
happening.

Fixes: b1479ebb7720 ("irqchip: atmel-aic: Add atmel AIC/AIC5 drivers")
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable@vger.kernel.org
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Link: http://lkml.kernel.org/r/1473775109-4192-2-git-send-email-boris.brezillon@free-electrons.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 6 insertions, 4 deletions

diff --git a/drivers/irqchip/irq-atmel-aic.c b/drivers/irqchip/irq-atmel-aic.c
index 112e17c2768b..37f952dd9fc9 100644
--- a/drivers/irqchip/irq-atmel-aic.c
+++ b/drivers/irqchip/irq-atmel-aic.c
@@ -176,6 +176,7 @@ static int aic_irq_domain_xlate(struct irq_domain *d,
 {
         struct irq_domain_chip_generic *dgc = d->gc;
         struct irq_chip_generic *gc;
+        unsigned long flags;
         unsigned smr;
         int idx;
         int ret;
@@ -194,11 +195,11 @@ static int aic_irq_domain_xlate(struct irq_domain *d,
 
         gc = dgc->gc[idx];
 
-        irq_gc_lock(gc);
+        irq_gc_lock_irqsave(gc, flags);
         smr = irq_reg_readl(gc, AT91_AIC_SMR(*out_hwirq));
         aic_common_set_priority(intspec[2], &smr);
         irq_reg_writel(gc, smr, AT91_AIC_SMR(*out_hwirq));
-        irq_gc_unlock(gc);
+        irq_gc_unlock_irqrestore(gc, flags);
 
         return ret;
 }
diff --git a/drivers/irqchip/irq-atmel-aic5.c b/drivers/irqchip/irq-atmel-aic5.c
index 4f0d068e1abe..2a624d87a035 100644
--- a/drivers/irqchip/irq-atmel-aic5.c
+++ b/drivers/irqchip/irq-atmel-aic5.c
@@ -258,6 +258,7 @@ static int aic5_irq_domain_xlate(struct irq_domain *d,
                                  unsigned int *out_type)
 {
         struct irq_chip_generic *bgc = irq_get_domain_generic_chip(d, 0);
+        unsigned long flags;
         unsigned smr;
         int ret;
 
@@ -269,12 +270,12 @@ static int aic5_irq_domain_xlate(struct irq_domain *d,
         if (ret)
                 return ret;
 
-        irq_gc_lock(bgc);
+        irq_gc_lock_irqsave(bgc, flags);
         irq_reg_writel(bgc, *out_hwirq, AT91_AIC5_SSR);
         smr = irq_reg_readl(bgc, AT91_AIC5_SMR);
         aic_common_set_priority(intspec[2], &smr);
         irq_reg_writel(bgc, smr, AT91_AIC5_SMR);
-        irq_gc_unlock(bgc);
+        irq_gc_unlock_irqrestore(bgc, flags);
 
         return ret;
 }