diff options
Diffstat (limited to 'kernel/irq/spurious.c')
| -rw-r--r-- | kernel/irq/spurious.c | 300 |
1 files changed, 178 insertions, 122 deletions
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c index 7b5f012bde9d..73280ccb74b0 100644 --- a/kernel/irq/spurious.c +++ b/kernel/irq/spurious.c @@ -1,6 +1,5 @@ +// SPDX-License-Identifier: GPL-2.0 /* - * linux/kernel/irq/spurious.c - * * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar * * This file contains spurious interrupt handling. @@ -9,7 +8,6 @@ #include <linux/jiffies.h> #include <linux/irq.h> #include <linux/module.h> -#include <linux/kallsyms.h> #include <linux/interrupt.h> #include <linux/moduleparam.h> #include <linux/timer.h> @@ -19,73 +17,43 @@ static int irqfixup __read_mostly; #define POLL_SPURIOUS_IRQ_INTERVAL (HZ/10) -static void poll_spurious_irqs(unsigned long dummy); -static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs, 0, 0); -static int irq_poll_cpu; +static void poll_spurious_irqs(struct timer_list *unused); +static DEFINE_TIMER(poll_spurious_irq_timer, poll_spurious_irqs); +int irq_poll_cpu; static atomic_t irq_poll_active; /* - * We wait here for a poller to finish. - * - * If the poll runs on this CPU, then we yell loudly and return - * false. That will leave the interrupt line disabled in the worst - * case, but it should never happen. - * - * We wait until the poller is done and then recheck disabled and - * action (about to be disabled). Only if it's still active, we return - * true and let the handler run. - */ -bool irq_wait_for_poll(struct irq_desc *desc) -{ - if (WARN_ONCE(irq_poll_cpu == smp_processor_id(), - "irq poll in progress on cpu %d for irq %d\n", - smp_processor_id(), desc->irq_data.irq)) - return false; - -#ifdef CONFIG_SMP - do { - raw_spin_unlock(&desc->lock); - while (irqd_irq_inprogress(&desc->irq_data)) - cpu_relax(); - raw_spin_lock(&desc->lock); - } while (irqd_irq_inprogress(&desc->irq_data)); - /* Might have been disabled in meantime */ - return !irqd_irq_disabled(&desc->irq_data) && desc->action; -#else - return false; -#endif -} - - -/* * Recovery handler for misrouted interrupts. */ -static int try_one_irq(int irq, struct irq_desc *desc, bool force) +static bool try_one_irq(struct irq_desc *desc, bool force) { - irqreturn_t ret = IRQ_NONE; struct irqaction *action; + bool ret = false; - raw_spin_lock(&desc->lock); + guard(raw_spinlock)(&desc->lock); - /* PER_CPU and nested thread interrupts are never polled */ - if (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(desc)) - goto out; + /* + * PER_CPU, nested thread interrupts and interrupts explicitly + * marked polled are excluded from polling. + */ + if (irq_settings_is_per_cpu(desc) || irq_settings_is_nested_thread(desc) || + irq_settings_is_polled(desc)) + return false; /* * Do not poll disabled interrupts unless the spurious - * disabled poller asks explicitely. + * disabled poller asks explicitly. */ if (irqd_irq_disabled(&desc->irq_data) && !force) - goto out; + return false; /* * All handlers must agree on IRQF_SHARED, so we test just the * first. */ action = desc->action; - if (!action || !(action->flags & IRQF_SHARED) || - (action->flags & __IRQF_TIMER)) - goto out; + if (!action || !(action->flags & IRQF_SHARED) || (action->flags & __IRQF_TIMER)) + return false; /* Already running on another processor */ if (irqd_irq_inprogress(&desc->irq_data)) { @@ -94,21 +62,19 @@ static int try_one_irq(int irq, struct irq_desc *desc, bool force) * CPU to go looking for our mystery interrupt too */ desc->istate |= IRQS_PENDING; - goto out; + return false; } /* Mark it poll in progress */ desc->istate |= IRQS_POLL_INPROGRESS; do { if (handle_irq_event(desc) == IRQ_HANDLED) - ret = IRQ_HANDLED; + ret = true; /* Make sure that there is still a valid action */ action = desc->action; } while ((desc->istate & IRQS_PENDING) && action); desc->istate &= ~IRQS_POLL_INPROGRESS; -out: - raw_spin_unlock(&desc->lock); - return ret == IRQ_HANDLED; + return ret; } static int misrouted_irq(int irq) @@ -128,7 +94,7 @@ static int misrouted_irq(int irq) if (i == irq) /* Already tried */ continue; - if (try_one_irq(i, desc, false)) + if (try_one_irq(desc, false)) ok = 1; } out: @@ -137,7 +103,7 @@ out: return ok; } -static void poll_spurious_irqs(unsigned long dummy) +static void poll_spurious_irqs(struct timer_list *unused) { struct irq_desc *desc; int i; @@ -153,24 +119,24 @@ static void poll_spurious_irqs(unsigned long dummy) continue; /* Racy but it doesn't matter */ - state = desc->istate; - barrier(); + state = READ_ONCE(desc->istate); if (!(state & IRQS_SPURIOUS_DISABLED)) continue; local_irq_disable(); - try_one_irq(i, desc, true); + try_one_irq(desc, true); local_irq_enable(); } out: atomic_dec(&irq_poll_active); - mod_timer(&poll_spurious_irq_timer, - jiffies + POLL_SPURIOUS_IRQ_INTERVAL); + mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL); } static inline int bad_action_ret(irqreturn_t action_ret) { - if (likely(action_ret <= (IRQ_HANDLED | IRQ_WAKE_THREAD))) + unsigned int r = action_ret; + + if (likely(r <= (IRQ_HANDLED | IRQ_WAKE_THREAD))) return 0; return 1; } @@ -183,22 +149,17 @@ static inline int bad_action_ret(irqreturn_t action_ret) * (The other 100-of-100,000 interrupts may have been a correctly * functioning device sharing an IRQ with the failing one) */ -static void -__report_bad_irq(unsigned int irq, struct irq_desc *desc, - irqreturn_t action_ret) +static void __report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret) { + unsigned int irq = irq_desc_get_irq(desc); struct irqaction *action; - unsigned long flags; - if (bad_action_ret(action_ret)) { - printk(KERN_ERR "irq event %d: bogus return value %x\n", - irq, action_ret); - } else { - printk(KERN_ERR "irq %d: nobody cared (try booting with " - "the \"irqpoll\" option)\n", irq); - } + if (bad_action_ret(action_ret)) + pr_err("irq event %d: bogus return value %x\n", irq, action_ret); + else + pr_err("irq %d: nobody cared (try booting with the \"irqpoll\" option)\n", irq); dump_stack(); - printk(KERN_ERR "handlers:\n"); + pr_err("handlers:\n"); /* * We need to take desc->lock here. note_interrupt() is called @@ -206,42 +167,36 @@ __report_bad_irq(unsigned int irq, struct irq_desc *desc, * with something else removing an action. It's ok to take * desc->lock here. See synchronize_irq(). */ - raw_spin_lock_irqsave(&desc->lock, flags); - action = desc->action; - while (action) { - printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler); + guard(raw_spinlock_irqsave)(&desc->lock); + for_each_action_of_desc(desc, action) { + pr_err("[<%p>] %ps", action->handler, action->handler); if (action->thread_fn) - printk(KERN_CONT " threaded [<%p>] %pf", - action->thread_fn, action->thread_fn); - printk(KERN_CONT "\n"); - action = action->next; + pr_cont(" threaded [<%p>] %ps", action->thread_fn, action->thread_fn); + pr_cont("\n"); } - raw_spin_unlock_irqrestore(&desc->lock, flags); } -static void -report_bad_irq(unsigned int irq, struct irq_desc *desc, irqreturn_t action_ret) +static void report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret) { static int count = 100; if (count > 0) { count--; - __report_bad_irq(irq, desc, action_ret); + __report_bad_irq(desc, action_ret); } } -static inline int -try_misrouted_irq(unsigned int irq, struct irq_desc *desc, - irqreturn_t action_ret) +static inline bool try_misrouted_irq(unsigned int irq, struct irq_desc *desc, + irqreturn_t action_ret) { struct irqaction *action; if (!irqfixup) - return 0; + return false; /* We didn't actually handle the IRQ - see if it was misrouted? */ if (action_ret == IRQ_NONE) - return 1; + return true; /* * But for 'irqfixup == 2' we also do it for handled interrupts if @@ -249,37 +204,133 @@ try_misrouted_irq(unsigned int irq, struct irq_desc *desc, * traditional PC timer interrupt.. Legacy) */ if (irqfixup < 2) - return 0; + return false; if (!irq) - return 1; + return true; /* * Since we don't get the descriptor lock, "action" can - * change under us. We don't really care, but we don't - * want to follow a NULL pointer. So tell the compiler to - * just load it once by using a barrier. + * change under us. */ - action = desc->action; - barrier(); + action = READ_ONCE(desc->action); return action && (action->flags & IRQF_IRQPOLL); } -void note_interrupt(unsigned int irq, struct irq_desc *desc, - irqreturn_t action_ret) +#define SPURIOUS_DEFERRED 0x80000000 + +void note_interrupt(struct irq_desc *desc, irqreturn_t action_ret) { - if (desc->istate & IRQS_POLL_INPROGRESS) - return; + unsigned int irq; - /* we get here again via the threaded handler */ - if (action_ret == IRQ_WAKE_THREAD) + if (desc->istate & IRQS_POLL_INPROGRESS || irq_settings_is_polled(desc)) return; if (bad_action_ret(action_ret)) { - report_bad_irq(irq, desc, action_ret); + report_bad_irq(desc, action_ret); return; } + /* + * We cannot call note_interrupt from the threaded handler + * because we need to look at the compound of all handlers + * (primary and threaded). Aside of that in the threaded + * shared case we have no serialization against an incoming + * hardware interrupt while we are dealing with a threaded + * result. + * + * So in case a thread is woken, we just note the fact and + * defer the analysis to the next hardware interrupt. + * + * The threaded handlers store whether they successfully + * handled an interrupt and we check whether that number + * changed versus the last invocation. + * + * We could handle all interrupts with the delayed by one + * mechanism, but for the non forced threaded case we'd just + * add pointless overhead to the straight hardirq interrupts + * for the sake of a few lines less code. + */ + if (action_ret & IRQ_WAKE_THREAD) { + /* + * There is a thread woken. Check whether one of the + * shared primary handlers returned IRQ_HANDLED. If + * not we defer the spurious detection to the next + * interrupt. + */ + if (action_ret == IRQ_WAKE_THREAD) { + int handled; + /* + * We use bit 31 of thread_handled_last to + * denote the deferred spurious detection + * active. No locking necessary as + * thread_handled_last is only accessed here + * and we have the guarantee that hard + * interrupts are not reentrant. + */ + if (!(desc->threads_handled_last & SPURIOUS_DEFERRED)) { + desc->threads_handled_last |= SPURIOUS_DEFERRED; + return; + } + /* + * Check whether one of the threaded handlers + * returned IRQ_HANDLED since the last + * interrupt happened. + * + * For simplicity we just set bit 31, as it is + * set in threads_handled_last as well. So we + * avoid extra masking. And we really do not + * care about the high bits of the handled + * count. We just care about the count being + * different than the one we saw before. + */ + handled = atomic_read(&desc->threads_handled); + handled |= SPURIOUS_DEFERRED; + if (handled != desc->threads_handled_last) { + action_ret = IRQ_HANDLED; + /* + * Note: We keep the SPURIOUS_DEFERRED + * bit set. We are handling the + * previous invocation right now. + * Keep it for the current one, so the + * next hardware interrupt will + * account for it. + */ + desc->threads_handled_last = handled; + } else { + /* + * None of the threaded handlers felt + * responsible for the last interrupt + * + * We keep the SPURIOUS_DEFERRED bit + * set in threads_handled_last as we + * need to account for the current + * interrupt as well. + */ + action_ret = IRQ_NONE; + } + } else { + /* + * One of the primary handlers returned + * IRQ_HANDLED. So we don't care about the + * threaded handlers on the same line. Clear + * the deferred detection bit. + * + * In theory we could/should check whether the + * deferred bit is set and take the result of + * the previous run into account here as + * well. But it's really not worth the + * trouble. If every other interrupt is + * handled we never trigger the spurious + * detector. And if this is just the one out + * of 100k unhandled ones which is handled + * then we merily delay the spurious detection + * by one hard interrupt. Not a real problem. + */ + desc->threads_handled_last &= ~SPURIOUS_DEFERRED; + } + } + if (unlikely(action_ret == IRQ_NONE)) { /* * If we are seeing only the odd spurious IRQ caused by @@ -294,12 +345,17 @@ void note_interrupt(unsigned int irq, struct irq_desc *desc, desc->last_unhandled = jiffies; } + irq = irq_desc_get_irq(desc); if (unlikely(try_misrouted_irq(irq, desc, action_ret))) { int ok = misrouted_irq(irq); if (action_ret == IRQ_NONE) desc->irqs_unhandled -= ok; } + if (likely(!desc->irqs_unhandled)) + return; + + /* Now getting into unhandled irq detection */ desc->irq_count++; if (likely(desc->irq_count < 100000)) return; @@ -309,17 +365,16 @@ void note_interrupt(unsigned int irq, struct irq_desc *desc, /* * The interrupt is stuck */ - __report_bad_irq(irq, desc, action_ret); + __report_bad_irq(desc, action_ret); /* * Now kill the IRQ */ - printk(KERN_EMERG "Disabling IRQ #%d\n", irq); + pr_emerg("Disabling IRQ #%d\n", irq); desc->istate |= IRQS_SPURIOUS_DISABLED; desc->depth++; irq_disable(desc); - mod_timer(&poll_spurious_irq_timer, - jiffies + POLL_SPURIOUS_IRQ_INTERVAL); + mod_timer(&poll_spurious_irq_timer, jiffies + POLL_SPURIOUS_IRQ_INTERVAL); } desc->irqs_unhandled = 0; } @@ -329,35 +384,36 @@ bool noirqdebug __read_mostly; int noirqdebug_setup(char *str) { noirqdebug = 1; - printk(KERN_INFO "IRQ lockup detection disabled\n"); - + pr_info("IRQ lockup detection disabled\n"); return 1; } - __setup("noirqdebug", noirqdebug_setup); module_param(noirqdebug, bool, 0644); MODULE_PARM_DESC(noirqdebug, "Disable irq lockup detection when true"); static int __init irqfixup_setup(char *str) { + if (IS_ENABLED(CONFIG_PREEMPT_RT)) { + pr_warn("irqfixup boot option not supported with PREEMPT_RT\n"); + return 1; + } irqfixup = 1; - printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n"); - printk(KERN_WARNING "This may impact system performance.\n"); - + pr_warn("Misrouted IRQ fixup support enabled.\n"); + pr_warn("This may impact system performance.\n"); return 1; } - __setup("irqfixup", irqfixup_setup); module_param(irqfixup, int, 0644); static int __init irqpoll_setup(char *str) { + if (IS_ENABLED(CONFIG_PREEMPT_RT)) { + pr_warn("irqpoll boot option not supported with PREEMPT_RT\n"); + return 1; + } irqfixup = 2; - printk(KERN_WARNING "Misrouted IRQ fixup and polling support " - "enabled\n"); - printk(KERN_WARNING "This may significantly impact system " - "performance\n"); + pr_warn("Misrouted IRQ fixup and polling support enabled\n"); + pr_warn("This may significantly impact system performance\n"); return 1; } - __setup("irqpoll", irqpoll_setup); |