From ebf9ff753c041b296241990aef76163bbb2cc9c8 Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Tue, 13 Sep 2016 15:58:28 +0200 Subject: [PATCH 1/2] genirq: Provide irq_gc_{lock_irqsave,unlock_irqrestore}() helpers Some irqchip drivers need to take the generic chip lock outside of the irq context. Provide the irq_gc_{lock_irqsave,unlock_irqrestore}() helpers to allow one to disable irqs while entering a critical section protected by gc->lock. Note that we do not provide optimized version of these helpers for !SMP, because they are not called from the hot-path. [ tglx: Added a comment when these helpers should be [not] used ] Signed-off-by: Boris Brezillon Cc: Jason Cooper Cc: Marc Zyngier Cc: Nicolas Ferre Cc: stable@vger.kernel.org Cc: Alexandre Belloni Link: http://lkml.kernel.org/r/1473775109-4192-1-git-send-email-boris.brezillon@free-electrons.com Signed-off-by: Thomas Gleixner --- include/linux/irq.h | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/include/linux/irq.h b/include/linux/irq.h index b52424eaa0ed..0ac26c892fe2 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -945,6 +945,16 @@ static inline void irq_gc_lock(struct irq_chip_generic *gc) { } static inline void irq_gc_unlock(struct irq_chip_generic *gc) { } #endif +/* + * The irqsave variants are for usage in non interrupt code. Do not use + * them in irq_chip callbacks. Use irq_gc_lock() instead. + */ +#define irq_gc_lock_irqsave(gc, flags) \ + raw_spin_lock_irqsave(&(gc)->lock, flags) + +#define irq_gc_unlock_irqrestore(gc, flags) \ + raw_spin_unlock_irqrestore(&(gc)->lock, flags) + static inline void irq_reg_writel(struct irq_chip_generic *gc, u32 val, int reg_offset) { From 5eb0d6eb3fac3daa60d9190eed9fa41cf809c756 Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Tue, 13 Sep 2016 15:58:29 +0200 Subject: [PATCH 2/2] 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 Acked-by: Marc Zyngier Cc: Jason Cooper Cc: Nicolas Ferre Cc: stable@vger.kernel.org Cc: Alexandre Belloni Link: http://lkml.kernel.org/r/1473775109-4192-2-git-send-email-boris.brezillon@free-electrons.com Signed-off-by: Thomas Gleixner --- drivers/irqchip/irq-atmel-aic.c | 5 +++-- drivers/irqchip/irq-atmel-aic5.c | 5 +++-- 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; }