diff options
Diffstat (limited to 'kernel/irq/manage.c')
-rw-r--r-- | kernel/irq/manage.c | 260 |
1 files changed, 214 insertions, 46 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index e68932bb308e..79c55c26eaee 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -22,6 +22,7 @@ #include "internals.h" #ifdef CONFIG_IRQ_FORCED_THREADING +# ifndef CONFIG_PREEMPT_RT_BASE __read_mostly bool force_irqthreads; static int __init setup_forced_irqthreads(char *arg) @@ -30,6 +31,7 @@ static int __init setup_forced_irqthreads(char *arg) return 0; } early_param("threadirqs", setup_forced_irqthreads); +# endif #endif static void __synchronize_hardirq(struct irq_desc *desc) @@ -179,6 +181,62 @@ static inline void irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { } #endif +#ifdef CONFIG_PREEMPT_RT_FULL +static void _irq_affinity_notify(struct irq_affinity_notify *notify); +static struct task_struct *set_affinity_helper; +static LIST_HEAD(affinity_list); +static DEFINE_RAW_SPINLOCK(affinity_list_lock); + +static int set_affinity_thread(void *unused) +{ + while (1) { + struct irq_affinity_notify *notify; + int empty; + + set_current_state(TASK_INTERRUPTIBLE); + + raw_spin_lock_irq(&affinity_list_lock); + empty = list_empty(&affinity_list); + raw_spin_unlock_irq(&affinity_list_lock); + + if (empty) + schedule(); + if (kthread_should_stop()) + break; + set_current_state(TASK_RUNNING); +try_next: + notify = NULL; + + raw_spin_lock_irq(&affinity_list_lock); + if (!list_empty(&affinity_list)) { + notify = list_first_entry(&affinity_list, + struct irq_affinity_notify, list); + list_del_init(¬ify->list); + } + raw_spin_unlock_irq(&affinity_list_lock); + + if (!notify) + continue; + _irq_affinity_notify(notify); + goto try_next; + } + return 0; +} + +static void init_helper_thread(void) +{ + if (set_affinity_helper) + return; + set_affinity_helper = kthread_run(set_affinity_thread, NULL, + "affinity-cb"); + WARN_ON(IS_ERR(set_affinity_helper)); +} +#else + +static inline void init_helper_thread(void) { } + +#endif + int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force) { @@ -218,7 +276,17 @@ int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask, if (desc->affinity_notify) { kref_get(&desc->affinity_notify->kref); + +#ifdef CONFIG_PREEMPT_RT_FULL + raw_spin_lock(&affinity_list_lock); + if (list_empty(&desc->affinity_notify->list)) + list_add_tail(&affinity_list, + &desc->affinity_notify->list); + raw_spin_unlock(&affinity_list_lock); + wake_up_process(set_affinity_helper); +#else schedule_work(&desc->affinity_notify->work); +#endif } irqd_set(data, IRQD_AFFINITY_SET); @@ -256,10 +324,8 @@ int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) } EXPORT_SYMBOL_GPL(irq_set_affinity_hint); -static void irq_affinity_notify(struct work_struct *work) +static void _irq_affinity_notify(struct irq_affinity_notify *notify) { - struct irq_affinity_notify *notify = - container_of(work, struct irq_affinity_notify, work); struct irq_desc *desc = irq_to_desc(notify->irq); cpumask_var_t cpumask; unsigned long flags; @@ -281,6 +347,13 @@ out: kref_put(¬ify->kref, notify->release); } +static void irq_affinity_notify(struct work_struct *work) +{ + struct irq_affinity_notify *notify = + container_of(work, struct irq_affinity_notify, work); + _irq_affinity_notify(notify); +} + /** * irq_set_affinity_notifier - control notification of IRQ affinity changes * @irq: Interrupt for which to enable/disable notification @@ -310,6 +383,8 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify) notify->irq = irq; kref_init(¬ify->kref); INIT_WORK(¬ify->work, irq_affinity_notify); + INIT_LIST_HEAD(¬ify->list); + init_helper_thread(); } raw_spin_lock_irqsave(&desc->lock, flags); @@ -697,6 +772,12 @@ static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id) return IRQ_NONE; } +static irqreturn_t irq_forced_secondary_handler(int irq, void *dev_id) +{ + WARN(1, "Secondary action handler called for irq %d\n", irq); + return IRQ_NONE; +} + static int irq_wait_for_interrupt(struct irqaction *action) { set_current_state(TASK_INTERRUPTIBLE); @@ -723,7 +804,8 @@ static int irq_wait_for_interrupt(struct irqaction *action) static void irq_finalize_oneshot(struct irq_desc *desc, struct irqaction *action) { - if (!(desc->istate & IRQS_ONESHOT)) + if (!(desc->istate & IRQS_ONESHOT) || + action->handler == irq_forced_secondary_handler) return; again: chip_bus_lock(desc); @@ -825,7 +907,15 @@ irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action) local_bh_disable(); ret = action->thread_fn(action->irq, action->dev_id); irq_finalize_oneshot(desc, action); - local_bh_enable(); + /* + * Interrupts which have real time requirements can be set up + * to avoid softirq processing in the thread handler. This is + * safe as these interrupts do not raise soft interrupts. + */ + if (irq_settings_no_softirq_call(desc)) + _local_bh_enable(); + else + local_bh_enable(); return ret; } @@ -877,6 +967,18 @@ static void irq_thread_dtor(struct callback_head *unused) irq_finalize_oneshot(desc, action); } +static void irq_wake_secondary(struct irq_desc *desc, struct irqaction *action) +{ + struct irqaction *secondary = action->secondary; + + if (WARN_ON_ONCE(!secondary)) + return; + + raw_spin_lock_irq(&desc->lock); + __irq_wake_thread(desc, secondary); + raw_spin_unlock_irq(&desc->lock); +} + /* * Interrupt handler thread */ @@ -907,7 +1009,15 @@ static int irq_thread(void *data) action_ret = handler_fn(desc, action); if (action_ret == IRQ_HANDLED) atomic_inc(&desc->threads_handled); - + if (action_ret == IRQ_WAKE_THREAD) + irq_wake_secondary(desc, action); + +#ifdef CONFIG_PREEMPT_RT_FULL + migrate_disable(); + add_interrupt_randomness(action->irq, 0, + desc->random_ip ^ (unsigned long) action); + migrate_enable(); +#endif wake_threads_waitq(desc); } @@ -951,20 +1061,36 @@ void irq_wake_thread(unsigned int irq, void *dev_id) } EXPORT_SYMBOL_GPL(irq_wake_thread); -static void irq_setup_forced_threading(struct irqaction *new) +static int irq_setup_forced_threading(struct irqaction *new) { if (!force_irqthreads) - return; + return 0; if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT)) - return; + return 0; new->flags |= IRQF_ONESHOT; - if (!new->thread_fn) { - set_bit(IRQTF_FORCED_THREAD, &new->thread_flags); - new->thread_fn = new->handler; - new->handler = irq_default_primary_handler; + /* + * Handle the case where we have a real primary handler and a + * thread handler. We force thread them as well by creating a + * secondary action. + */ + if (new->handler != irq_default_primary_handler && new->thread_fn) { + /* Allocate the secondary action */ + new->secondary = kzalloc(sizeof(struct irqaction), GFP_KERNEL); + if (!new->secondary) + return -ENOMEM; + new->secondary->handler = irq_forced_secondary_handler; + new->secondary->thread_fn = new->thread_fn; + new->secondary->dev_id = new->dev_id; + new->secondary->irq = new->irq; + new->secondary->name = new->name; } + /* Deal with the primary handler */ + set_bit(IRQTF_FORCED_THREAD, &new->thread_flags); + new->thread_fn = new->handler; + new->handler = irq_default_primary_handler; + return 0; } static int irq_request_resources(struct irq_desc *desc) @@ -984,6 +1110,48 @@ static void irq_release_resources(struct irq_desc *desc) c->irq_release_resources(d); } +static int +setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary) +{ + struct task_struct *t; + struct sched_param param = { + .sched_priority = MAX_USER_RT_PRIO/2, + }; + + if (!secondary) { + t = kthread_create(irq_thread, new, "irq/%d-%s", irq, + new->name); + } else { + t = kthread_create(irq_thread, new, "irq/%d-s-%s", irq, + new->name); + param.sched_priority += 1; + } + + if (IS_ERR(t)) + return PTR_ERR(t); + + sched_setscheduler_nocheck(t, SCHED_FIFO, ¶m); + + /* + * We keep the reference to the task struct even if + * the thread dies to avoid that the interrupt code + * references an already freed task_struct. + */ + get_task_struct(t); + new->thread = t; + /* + * Tell the thread to set its affinity. This is + * important for shared interrupt handlers as we do + * not invoke setup_affinity() for the secondary + * handlers as everything is already set up. Even for + * interrupts marked with IRQF_NO_BALANCE this is + * correct as we want the thread to move to the cpu(s) + * on which the requesting code placed the interrupt. + */ + set_bit(IRQTF_AFFINITY, &new->thread_flags); + return 0; +} + /* * Internal function to register an irqaction - typically used to * allocate special interrupts that are part of the architecture. @@ -1004,6 +1172,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) if (!try_module_get(desc->owner)) return -ENODEV; + new->irq = irq; + /* * Check whether the interrupt nests into another interrupt * thread. @@ -1021,8 +1191,11 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) */ new->handler = irq_nested_primary_handler; } else { - if (irq_settings_can_thread(desc)) - irq_setup_forced_threading(new); + if (irq_settings_can_thread(desc)) { + ret = irq_setup_forced_threading(new); + if (ret) + goto out_mput; + } } /* @@ -1031,37 +1204,14 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) * thread. */ if (new->thread_fn && !nested) { - struct task_struct *t; - static const struct sched_param param = { - .sched_priority = MAX_USER_RT_PRIO/2, - }; - - t = kthread_create(irq_thread, new, "irq/%d-%s", irq, - new->name); - if (IS_ERR(t)) { - ret = PTR_ERR(t); + ret = setup_irq_thread(new, irq, false); + if (ret) goto out_mput; + if (new->secondary) { + ret = setup_irq_thread(new->secondary, irq, true); + if (ret) + goto out_thread; } - - sched_setscheduler_nocheck(t, SCHED_FIFO, ¶m); - - /* - * We keep the reference to the task struct even if - * the thread dies to avoid that the interrupt code - * references an already freed task_struct. - */ - get_task_struct(t); - new->thread = t; - /* - * Tell the thread to set its affinity. This is - * important for shared interrupt handlers as we do - * not invoke setup_affinity() for the secondary - * handlers as everything is already set up. Even for - * interrupts marked with IRQF_NO_BALANCE this is - * correct as we want the thread to move to the cpu(s) - * on which the requesting code placed the interrupt. - */ - set_bit(IRQTF_AFFINITY, &new->thread_flags); } if (!alloc_cpumask_var(&mask, GFP_KERNEL)) { @@ -1221,6 +1371,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) irqd_set(&desc->irq_data, IRQD_NO_BALANCING); } + if (new->flags & IRQF_NO_SOFTIRQ_CALL) + irq_settings_set_no_softirq_call(desc); + /* Set default affinity mask once everything is setup */ setup_affinity(irq, desc, mask); @@ -1234,7 +1387,6 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) irq, nmsk, omsk); } - new->irq = irq; *old_ptr = new; irq_pm_install_action(desc, new); @@ -1260,6 +1412,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) */ if (new->thread) wake_up_process(new->thread); + if (new->secondary) + wake_up_process(new->secondary->thread); register_irq_proc(irq, desc); new->dir = NULL; @@ -1290,6 +1444,13 @@ out_thread: kthread_stop(t); put_task_struct(t); } + if (new->secondary && new->secondary->thread) { + struct task_struct *t = new->secondary->thread; + + new->secondary->thread = NULL; + kthread_stop(t); + put_task_struct(t); + } out_mput: module_put(desc->owner); return ret; @@ -1397,9 +1558,14 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) if (action->thread) { kthread_stop(action->thread); put_task_struct(action->thread); + if (action->secondary && action->secondary->thread) { + kthread_stop(action->secondary->thread); + put_task_struct(action->secondary->thread); + } } module_put(desc->owner); + kfree(action->secondary); return action; } @@ -1543,8 +1709,10 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler, retval = __setup_irq(irq, desc, action); chip_bus_sync_unlock(desc); - if (retval) + if (retval) { + kfree(action->secondary); kfree(action); + } #ifdef CONFIG_DEBUG_SHIRQ_FIXME if (!retval && (irqflags & IRQF_SHARED)) { |