From a304e1b82808904c561b7b149b467e338c53fcce Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Mon, 12 Feb 2007 00:52:00 -0800 Subject: [PATCH] Debug shared irqs Drivers registering IRQ handlers with SA_SHIRQ really ought to be able to handle an interrupt happening before request_irq() returns. They also ought to be able to handle an interrupt happening during the start of their call to free_irq(). Let's test that hypothesis.... [bunk@stusta.de: Kconfig fixes] Signed-off-by: David Woodhouse Cc: Arjan van de Ven Signed-off-by: Jesper Juhl Signed-off-by: Ingo Molnar Signed-off-by: Adrian Bunk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 8b961ad..400b12a 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -357,6 +357,7 @@ void free_irq(unsigned int irq, void *dev_id) struct irq_desc *desc; struct irqaction **p; unsigned long flags; + irqreturn_t (*handler)(int, void *) = NULL; WARN_ON(in_interrupt()); if (irq >= NR_IRQS) @@ -396,6 +397,8 @@ void free_irq(unsigned int irq, void *dev_id) /* Make sure it's not being used on another CPU */ synchronize_irq(irq); + if (action->flags & IRQF_SHARED) + handler = action->handler; kfree(action); return; } @@ -403,6 +406,17 @@ void free_irq(unsigned int irq, void *dev_id) spin_unlock_irqrestore(&desc->lock, flags); return; } +#ifdef CONFIG_DEBUG_SHIRQ + if (handler) { + /* + * It's a shared IRQ -- the driver ought to be prepared for it + * to happen even now it's being freed, so let's make sure.... + * We do this after actually deregistering it, to make sure that + * a 'real' IRQ doesn't run in parallel with our fake + */ + handler(irq, dev_id); + } +#endif } EXPORT_SYMBOL(free_irq); @@ -475,6 +489,25 @@ int request_irq(unsigned int irq, irq_handler_t handler, select_smp_affinity(irq); +#ifdef CONFIG_DEBUG_SHIRQ + if (irqflags & IRQF_SHARED) { + /* + * It's a shared IRQ -- the driver ought to be prepared for it + * to happen immediately, so let's make sure.... + * We do this before actually registering it, to make sure that + * a 'real' IRQ doesn't run in parallel with our fake + */ + if (irqflags & IRQF_DISABLED) { + unsigned long flags; + + local_irq_save(flags); + handler(irq, dev_id); + local_irq_restore(flags); + } else + handler(irq, dev_id); + } +#endif + retval = setup_irq(irq, action); if (retval) kfree(action); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 356a5ab..63f04c1 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -77,6 +77,15 @@ config DEBUG_KERNEL Say Y here if you are developing drivers or trying to debug and identify kernel problems. +config DEBUG_SHIRQ + bool "Debug shared IRQ handlers" + depends on DEBUG_KERNEL && GENERIC_HARDIRQS + help + Enable this to generate a spurious interrupt as soon as a shared + interrupt handler is registered, and just before one is deregistered. + Drivers ought to be able to handle interrupts coming in at those + points; some don't and need to be caught. + config LOG_BUF_SHIFT int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL range 12 21 -- cgit v0.10.2