// 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
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*
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* This file contains the IRQ-resend code
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*
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* If the interrupt is waiting to be processed, we try to re-run it.
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* We can't directly run it from here since the caller might be in an
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* interrupt-protected region. Not all irq controller chips can
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* retrigger interrupts at the hardware level, so in those cases
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* we allow the resending of IRQs via a tasklet.
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*/
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#include <linux/irq.h>
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#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/interrupt.h>
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#include "internals.h"
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#ifdef CONFIG_HARDIRQS_SW_RESEND
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/* Bitmap to handle software resend of interrupts: */
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static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS);
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/*
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* Run software resends of IRQ's
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*/
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static void resend_irqs(unsigned long arg)
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{
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struct irq_desc *desc;
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int irq;
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while (!bitmap_empty(irqs_resend, nr_irqs)) {
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irq = find_first_bit(irqs_resend, nr_irqs);
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clear_bit(irq, irqs_resend);
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desc = irq_to_desc(irq);
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if (!desc)
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continue;
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local_irq_disable();
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desc->handle_irq(desc);
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local_irq_enable();
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}
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}
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/* Tasklet to handle resend: */
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static DECLARE_TASKLET_OLD(resend_tasklet, resend_irqs);
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static int irq_sw_resend(struct irq_desc *desc)
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{
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unsigned int irq = irq_desc_get_irq(desc);
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/*
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* Validate whether this interrupt can be safely injected from
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* non interrupt context
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*/
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if (handle_enforce_irqctx(&desc->irq_data))
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return -EINVAL;
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/*
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* If the interrupt is running in the thread context of the parent
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* irq we need to be careful, because we cannot trigger it
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* directly.
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*/
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if (irq_settings_is_nested_thread(desc)) {
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/*
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* If the parent_irq is valid, we retrigger the parent,
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* otherwise we do nothing.
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*/
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if (!desc->parent_irq)
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return -EINVAL;
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irq = desc->parent_irq;
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}
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/* Set it pending and activate the softirq: */
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set_bit(irq, irqs_resend);
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tasklet_schedule(&resend_tasklet);
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return 0;
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}
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#else
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static int irq_sw_resend(struct irq_desc *desc)
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{
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return -EINVAL;
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}
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#endif
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static int try_retrigger(struct irq_desc *desc)
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{
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if (desc->irq_data.chip->irq_retrigger)
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return desc->irq_data.chip->irq_retrigger(&desc->irq_data);
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#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
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return irq_chip_retrigger_hierarchy(&desc->irq_data);
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#else
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return 0;
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#endif
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}
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/*
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* IRQ resend
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*
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* Is called with interrupts disabled and desc->lock held.
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*/
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int check_irq_resend(struct irq_desc *desc, bool inject)
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{
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int err = 0;
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/*
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* We do not resend level type interrupts. Level type interrupts
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* are resent by hardware when they are still active. Clear the
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* pending bit so suspend/resume does not get confused.
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*/
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if (irq_settings_is_level(desc)) {
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desc->istate &= ~IRQS_PENDING;
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return -EINVAL;
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}
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if (desc->istate & IRQS_REPLAY)
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return -EBUSY;
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if (!(desc->istate & IRQS_PENDING) && !inject)
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return 0;
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desc->istate &= ~IRQS_PENDING;
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if (!try_retrigger(desc))
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err = irq_sw_resend(desc);
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/* If the retrigger was successfull, mark it with the REPLAY bit */
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if (!err)
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desc->istate |= IRQS_REPLAY;
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return err;
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}
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#ifdef CONFIG_GENERIC_IRQ_INJECTION
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/**
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* irq_inject_interrupt - Inject an interrupt for testing/error injection
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* @irq: The interrupt number
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*
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* This function must only be used for debug and testing purposes!
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*
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* Especially on x86 this can cause a premature completion of an interrupt
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* affinity change causing the interrupt line to become stale. Very
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* unlikely, but possible.
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*
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* The injection can fail for various reasons:
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* - Interrupt is not activated
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* - Interrupt is NMI type or currently replaying
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* - Interrupt is level type
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* - Interrupt does not support hardware retrigger and software resend is
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* either not enabled or not possible for the interrupt.
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*/
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int irq_inject_interrupt(unsigned int irq)
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{
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struct irq_desc *desc;
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unsigned long flags;
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int err;
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/* Try the state injection hardware interface first */
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if (!irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true))
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return 0;
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/* That failed, try via the resend mechanism */
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desc = irq_get_desc_buslock(irq, &flags, 0);
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if (!desc)
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return -EINVAL;
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/*
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* Only try to inject when the interrupt is:
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* - not NMI type
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* - activated
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*/
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if ((desc->istate & IRQS_NMI) || !irqd_is_activated(&desc->irq_data))
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err = -EINVAL;
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else
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err = check_irq_resend(desc, true);
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irq_put_desc_busunlock(desc, flags);
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return err;
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}
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EXPORT_SYMBOL_GPL(irq_inject_interrupt);
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#endif
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