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229 lines
5.8 KiB
229 lines
5.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar |
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* Copyright (C) 2005-2006, Thomas Gleixner, Russell King |
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* |
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* This file contains the core interrupt handling code. Detailed |
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* information is available in Documentation/core-api/genericirq.rst |
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* |
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*/ |
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#include <linux/irq.h> |
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#include <linux/random.h> |
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#include <linux/sched.h> |
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#include <linux/interrupt.h> |
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#include <linux/kernel_stat.h> |
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#include <trace/events/irq.h> |
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#include "internals.h" |
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#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER |
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void (*handle_arch_irq)(struct pt_regs *) __ro_after_init; |
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#endif |
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/** |
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* handle_bad_irq - handle spurious and unhandled irqs |
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* @desc: description of the interrupt |
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* |
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* Handles spurious and unhandled IRQ's. It also prints a debugmessage. |
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*/ |
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void handle_bad_irq(struct irq_desc *desc) |
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{ |
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unsigned int irq = irq_desc_get_irq(desc); |
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print_irq_desc(irq, desc); |
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kstat_incr_irqs_this_cpu(desc); |
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ack_bad_irq(irq); |
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} |
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EXPORT_SYMBOL_GPL(handle_bad_irq); |
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/* |
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* Special, empty irq handler: |
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*/ |
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irqreturn_t no_action(int cpl, void *dev_id) |
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{ |
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return IRQ_NONE; |
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} |
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EXPORT_SYMBOL_GPL(no_action); |
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static void warn_no_thread(unsigned int irq, struct irqaction *action) |
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{ |
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if (test_and_set_bit(IRQTF_WARNED, &action->thread_flags)) |
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return; |
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printk(KERN_WARNING "IRQ %d device %s returned IRQ_WAKE_THREAD " |
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"but no thread function available.", irq, action->name); |
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} |
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void __irq_wake_thread(struct irq_desc *desc, struct irqaction *action) |
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{ |
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/* |
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* In case the thread crashed and was killed we just pretend that |
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* we handled the interrupt. The hardirq handler has disabled the |
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* device interrupt, so no irq storm is lurking. |
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*/ |
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if (action->thread->flags & PF_EXITING) |
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return; |
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/* |
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* Wake up the handler thread for this action. If the |
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* RUNTHREAD bit is already set, nothing to do. |
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*/ |
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if (test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags)) |
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return; |
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/* |
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* It's safe to OR the mask lockless here. We have only two |
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* places which write to threads_oneshot: This code and the |
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* irq thread. |
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* |
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* This code is the hard irq context and can never run on two |
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* cpus in parallel. If it ever does we have more serious |
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* problems than this bitmask. |
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* |
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* The irq threads of this irq which clear their "running" bit |
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* in threads_oneshot are serialized via desc->lock against |
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* each other and they are serialized against this code by |
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* IRQS_INPROGRESS. |
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* |
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* Hard irq handler: |
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* |
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* spin_lock(desc->lock); |
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* desc->state |= IRQS_INPROGRESS; |
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* spin_unlock(desc->lock); |
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* set_bit(IRQTF_RUNTHREAD, &action->thread_flags); |
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* desc->threads_oneshot |= mask; |
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* spin_lock(desc->lock); |
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* desc->state &= ~IRQS_INPROGRESS; |
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* spin_unlock(desc->lock); |
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* |
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* irq thread: |
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* |
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* again: |
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* spin_lock(desc->lock); |
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* if (desc->state & IRQS_INPROGRESS) { |
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* spin_unlock(desc->lock); |
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* while(desc->state & IRQS_INPROGRESS) |
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* cpu_relax(); |
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* goto again; |
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* } |
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* if (!test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) |
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* desc->threads_oneshot &= ~mask; |
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* spin_unlock(desc->lock); |
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* |
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* So either the thread waits for us to clear IRQS_INPROGRESS |
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* or we are waiting in the flow handler for desc->lock to be |
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* released before we reach this point. The thread also checks |
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* IRQTF_RUNTHREAD under desc->lock. If set it leaves |
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* threads_oneshot untouched and runs the thread another time. |
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*/ |
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desc->threads_oneshot |= action->thread_mask; |
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/* |
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* We increment the threads_active counter in case we wake up |
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* the irq thread. The irq thread decrements the counter when |
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* it returns from the handler or in the exit path and wakes |
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* up waiters which are stuck in synchronize_irq() when the |
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* active count becomes zero. synchronize_irq() is serialized |
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* against this code (hard irq handler) via IRQS_INPROGRESS |
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* like the finalize_oneshot() code. See comment above. |
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*/ |
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atomic_inc(&desc->threads_active); |
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wake_up_process(action->thread); |
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} |
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irqreturn_t __handle_irq_event_percpu(struct irq_desc *desc, unsigned int *flags) |
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{ |
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irqreturn_t retval = IRQ_NONE; |
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unsigned int irq = desc->irq_data.irq; |
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struct irqaction *action; |
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record_irq_time(desc); |
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for_each_action_of_desc(desc, action) { |
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irqreturn_t res; |
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/* |
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* If this IRQ would be threaded under force_irqthreads, mark it so. |
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*/ |
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if (irq_settings_can_thread(desc) && |
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!(action->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))) |
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lockdep_hardirq_threaded(); |
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trace_irq_handler_entry(irq, action); |
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res = action->handler(irq, action->dev_id); |
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trace_irq_handler_exit(irq, action, res); |
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if (WARN_ONCE(!irqs_disabled(),"irq %u handler %pS enabled interrupts\n", |
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irq, action->handler)) |
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local_irq_disable(); |
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switch (res) { |
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case IRQ_WAKE_THREAD: |
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/* |
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* Catch drivers which return WAKE_THREAD but |
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* did not set up a thread function |
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*/ |
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if (unlikely(!action->thread_fn)) { |
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warn_no_thread(irq, action); |
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break; |
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} |
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__irq_wake_thread(desc, action); |
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fallthrough; /* to add to randomness */ |
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case IRQ_HANDLED: |
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*flags |= action->flags; |
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break; |
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default: |
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break; |
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} |
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retval |= res; |
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} |
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return retval; |
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} |
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irqreturn_t handle_irq_event_percpu(struct irq_desc *desc) |
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{ |
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irqreturn_t retval; |
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unsigned int flags = 0; |
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retval = __handle_irq_event_percpu(desc, &flags); |
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add_interrupt_randomness(desc->irq_data.irq, flags); |
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if (!irq_settings_no_debug(desc)) |
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note_interrupt(desc, retval); |
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return retval; |
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} |
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irqreturn_t handle_irq_event(struct irq_desc *desc) |
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{ |
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irqreturn_t ret; |
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desc->istate &= ~IRQS_PENDING; |
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irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS); |
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raw_spin_unlock(&desc->lock); |
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ret = handle_irq_event_percpu(desc); |
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raw_spin_lock(&desc->lock); |
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irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS); |
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return ret; |
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} |
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#ifdef CONFIG_GENERIC_IRQ_MULTI_HANDLER |
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int __init set_handle_irq(void (*handle_irq)(struct pt_regs *)) |
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{ |
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if (handle_arch_irq) |
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return -EBUSY; |
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handle_arch_irq = handle_irq; |
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return 0; |
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} |
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#endif
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