From f0cb32207307e9d7b3ee8117078b7a37f8d0166e Mon Sep 17 00:00:00 2001 From: Thomas Petazzoni Date: Tue, 20 Oct 2015 15:23:51 +0200 Subject: [PATCH] genirq: Implement irq_percpu_is_enabled() Certain interrupt controller drivers have a register set that does not make it easy to save/restore the mask of enabled/disabled interrupts at suspend/resume time. At resume time, such drivers rely on the core kernel irq subsystem to tell whether such or such interrupt is enabled or not, in order to restore the proper state in the interrupt controller register. While the irqd_irq_disabled() provides the relevant information for global interrupts, there is no similar function to query the enabled/disabled state of a per-CPU interrupt. Therefore, this commit complements the percpu_irq API with an irq_percpu_is_enabled() function. [ tglx: Simplified the implementation and added kerneldoc ] Signed-off-by: Thomas Petazzoni Cc: linux-arm-kernel@lists.infradead.org Cc: Tawfik Bayouk Cc: Nadav Haklai Cc: Lior Amsalem Cc: Andrew Lunn Cc: Sebastian Hesselbarth Cc: Gregory Clement Cc: Jason Cooper Cc: Marc Zyngier Link: http://lkml.kernel.org/r/1445347435-2333-2-git-send-email-thomas.petazzoni@free-electrons.com Signed-off-by: Thomas Gleixner --- include/linux/interrupt.h | 1 + kernel/irq/manage.c | 25 +++++++++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index ad16809c8596..cb30edbfe9fc 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -195,6 +195,7 @@ extern void disable_irq(unsigned int irq); extern void disable_percpu_irq(unsigned int irq); extern void enable_irq(unsigned int irq); extern void enable_percpu_irq(unsigned int irq, unsigned int type); +extern bool irq_percpu_is_enabled(unsigned int irq); extern void irq_wake_thread(unsigned int irq, void *dev_id); /* The following three functions are for the core kernel use only. */ diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 0eebaeef317b..c84670c373f9 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1743,6 +1743,31 @@ out: } EXPORT_SYMBOL_GPL(enable_percpu_irq); +/** + * irq_percpu_is_enabled - Check whether the per cpu irq is enabled + * @irq: Linux irq number to check for + * + * Must be called from a non migratable context. Returns the enable + * state of a per cpu interrupt on the current cpu. + */ +bool irq_percpu_is_enabled(unsigned int irq) +{ + unsigned int cpu = smp_processor_id(); + struct irq_desc *desc; + unsigned long flags; + bool is_enabled; + + desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU); + if (!desc) + return false; + + is_enabled = cpumask_test_cpu(cpu, desc->percpu_enabled); + irq_put_desc_unlock(desc, flags); + + return is_enabled; +} +EXPORT_SYMBOL_GPL(irq_percpu_is_enabled); + void disable_percpu_irq(unsigned int irq) { unsigned int cpu = smp_processor_id(); -- 2.34.1