diff options
Diffstat (limited to 'kernel/irq/handle.c')
-rw-r--r-- | kernel/irq/handle.c | 144 |
1 files changed, 113 insertions, 31 deletions
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c index 3540a7190122..517561fc7317 100644 --- a/kernel/irq/handle.c +++ b/kernel/irq/handle.c @@ -51,30 +51,92 @@ static void warn_no_thread(unsigned int irq, struct irqaction *action) "but no thread function available.", irq, action->name); } -/** - * handle_IRQ_event - irq action chain handler - * @irq: the interrupt number - * @action: the interrupt action chain for this irq - * - * Handles the action chain of an irq event - */ -irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) +static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action) +{ + /* + * Wake up the handler thread for this action. In case the + * thread crashed and was killed we just pretend that we + * handled the interrupt. The hardirq handler has disabled the + * device interrupt, so no irq storm is lurking. If the + * RUNTHREAD bit is already set, nothing to do. + */ + if (test_bit(IRQTF_DIED, &action->thread_flags) || + test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags)) + return; + + /* + * It's safe to OR the mask lockless here. We have only two + * places which write to threads_oneshot: This code and the + * irq thread. + * + * This code is the hard irq context and can never run on two + * cpus in parallel. If it ever does we have more serious + * problems than this bitmask. + * + * The irq threads of this irq which clear their "running" bit + * in threads_oneshot are serialized via desc->lock against + * each other and they are serialized against this code by + * IRQS_INPROGRESS. + * + * Hard irq handler: + * + * spin_lock(desc->lock); + * desc->state |= IRQS_INPROGRESS; + * spin_unlock(desc->lock); + * set_bit(IRQTF_RUNTHREAD, &action->thread_flags); + * desc->threads_oneshot |= mask; + * spin_lock(desc->lock); + * desc->state &= ~IRQS_INPROGRESS; + * spin_unlock(desc->lock); + * + * irq thread: + * + * again: + * spin_lock(desc->lock); + * if (desc->state & IRQS_INPROGRESS) { + * spin_unlock(desc->lock); + * while(desc->state & IRQS_INPROGRESS) + * cpu_relax(); + * goto again; + * } + * if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) + * desc->threads_oneshot &= ~mask; + * spin_unlock(desc->lock); + * + * So either the thread waits for us to clear IRQS_INPROGRESS + * or we are waiting in the flow handler for desc->lock to be + * released before we reach this point. The thread also checks + * IRQTF_RUNTHREAD under desc->lock. If set it leaves + * threads_oneshot untouched and runs the thread another time. + */ + desc->threads_oneshot |= action->thread_mask; + wake_up_process(action->thread); +} + +irqreturn_t +handle_irq_event_percpu(struct irq_desc *desc, struct irqaction *action) { - irqreturn_t ret, retval = IRQ_NONE; - unsigned int status = 0; + irqreturn_t retval = IRQ_NONE; + unsigned int random = 0, irq = desc->irq_data.irq; do { + irqreturn_t res; + trace_irq_handler_entry(irq, action); - ret = action->handler(irq, action->dev_id); - trace_irq_handler_exit(irq, action, ret); + res = action->handler(irq, action->dev_id); + trace_irq_handler_exit(irq, action, res); - switch (ret) { + if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pF enabled interrupts\n", + irq, action->handler)) + local_irq_disable(); + + switch (res) { case IRQ_WAKE_THREAD: /* * Set result to handled so the spurious check * does not trigger. */ - ret = IRQ_HANDLED; + res = IRQ_HANDLED; /* * Catch drivers which return WAKE_THREAD but @@ -85,36 +147,56 @@ irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) break; } - /* - * Wake up the handler thread for this - * action. In case the thread crashed and was - * killed we just pretend that we handled the - * interrupt. The hardirq handler above has - * disabled the device interrupt, so no irq - * storm is lurking. - */ - if (likely(!test_bit(IRQTF_DIED, - &action->thread_flags))) { - set_bit(IRQTF_RUNTHREAD, &action->thread_flags); - wake_up_process(action->thread); - } + irq_wake_thread(desc, action); /* Fall through to add to randomness */ case IRQ_HANDLED: - status |= action->flags; + random |= action->flags; break; default: break; } - retval |= ret; + retval |= res; action = action->next; } while (action); - if (status & IRQF_SAMPLE_RANDOM) + if (random & IRQF_SAMPLE_RANDOM) add_interrupt_randomness(irq); - local_irq_disable(); + if (!noirqdebug) + note_interrupt(irq, desc, retval); return retval; } + +irqreturn_t handle_irq_event(struct irq_desc *desc) +{ + struct irqaction *action = desc->action; + irqreturn_t ret; + + irq_compat_clr_pending(desc); + desc->istate &= ~IRQS_PENDING; + irq_compat_set_progress(desc); + desc->istate |= IRQS_INPROGRESS; + raw_spin_unlock(&desc->lock); + + ret = handle_irq_event_percpu(desc, action); + + raw_spin_lock(&desc->lock); + desc->istate &= ~IRQS_INPROGRESS; + irq_compat_clr_progress(desc); + return ret; +} + +/** + * handle_IRQ_event - irq action chain handler + * @irq: the interrupt number + * @action: the interrupt action chain for this irq + * + * Handles the action chain of an irq event + */ +irqreturn_t handle_IRQ_event(unsigned int irq, struct irqaction *action) +{ + return handle_irq_event_percpu(irq_to_desc(irq), action); +} |