From cf613871946230c5dd8178d07bcdc2984f4545cd Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 6 Mar 2015 16:37:44 +0000 Subject: [PATCH] irqchip: gic: Fix unsafe locking reported by lockdep When compiled with CONFIG_LOCKDEP, the kernel shouts badly, saying that the locking in the GIC code is unsafe. I'm afraid the kernel is right: CPU0 ---- lock(irq_controller_lock); lock(irq_controller_lock); *** DEADLOCK *** This can happen while enabling, disabling, setting the type or the affinity of an interrupt. The fix is to take the interrupt_controller_lock with interrupts disabled in these cases. Signed-off-by: Marc Zyngier Link: https://lkml.kernel.org/r/1425659870-11832-6-git-send-email-marc.zyngier@arm.com Signed-off-by: Jason Cooper --- drivers/irqchip/irq-gic.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c index 4634cf7d0ec3..471e1cdc1933 100644 --- a/drivers/irqchip/irq-gic.c +++ b/drivers/irqchip/irq-gic.c @@ -154,23 +154,25 @@ static inline unsigned int gic_irq(struct irq_data *d) static void gic_mask_irq(struct irq_data *d) { u32 mask = 1 << (gic_irq(d) % 32); + unsigned long flags; - raw_spin_lock(&irq_controller_lock); + raw_spin_lock_irqsave(&irq_controller_lock, flags); writel_relaxed(mask, gic_dist_base(d) + GIC_DIST_ENABLE_CLEAR + (gic_irq(d) / 32) * 4); if (gic_arch_extn.irq_mask) gic_arch_extn.irq_mask(d); - raw_spin_unlock(&irq_controller_lock); + raw_spin_unlock_irqrestore(&irq_controller_lock, flags); } static void gic_unmask_irq(struct irq_data *d) { u32 mask = 1 << (gic_irq(d) % 32); + unsigned long flags; - raw_spin_lock(&irq_controller_lock); + raw_spin_lock_irqsave(&irq_controller_lock, flags); if (gic_arch_extn.irq_unmask) gic_arch_extn.irq_unmask(d); writel_relaxed(mask, gic_dist_base(d) + GIC_DIST_ENABLE_SET + (gic_irq(d) / 32) * 4); - raw_spin_unlock(&irq_controller_lock); + raw_spin_unlock_irqrestore(&irq_controller_lock, flags); } static void gic_eoi_irq(struct irq_data *d) @@ -188,6 +190,7 @@ static int gic_set_type(struct irq_data *d, unsigned int type) { void __iomem *base = gic_dist_base(d); unsigned int gicirq = gic_irq(d); + unsigned long flags; int ret; /* Interrupt configuration for SGIs can't be changed */ @@ -199,14 +202,14 @@ static int gic_set_type(struct irq_data *d, unsigned int type) type != IRQ_TYPE_EDGE_RISING) return -EINVAL; - raw_spin_lock(&irq_controller_lock); + raw_spin_lock_irqsave(&irq_controller_lock, flags); if (gic_arch_extn.irq_set_type) gic_arch_extn.irq_set_type(d, type); ret = gic_configure_irq(gicirq, type, base, NULL); - raw_spin_unlock(&irq_controller_lock); + raw_spin_unlock_irqrestore(&irq_controller_lock, flags); return ret; } @@ -227,6 +230,7 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val, void __iomem *reg = gic_dist_base(d) + GIC_DIST_TARGET + (gic_irq(d) & ~3); unsigned int cpu, shift = (gic_irq(d) % 4) * 8; u32 val, mask, bit; + unsigned long flags; if (!force) cpu = cpumask_any_and(mask_val, cpu_online_mask); @@ -236,12 +240,12 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val, if (cpu >= NR_GIC_CPU_IF || cpu >= nr_cpu_ids) return -EINVAL; - raw_spin_lock(&irq_controller_lock); + raw_spin_lock_irqsave(&irq_controller_lock, flags); mask = 0xff << shift; bit = gic_cpu_map[cpu] << shift; val = readl_relaxed(reg) & ~mask; writel_relaxed(val | bit, reg); - raw_spin_unlock(&irq_controller_lock); + raw_spin_unlock_irqrestore(&irq_controller_lock, flags); return IRQ_SET_MASK_OK; } -- 2.20.1