// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar * Copyright (C) 2005-2006, Thomas Gleixner * * This file contains the IRQ-resend code * * If the interrupt is waiting to be processed, we try to re-run it. * We can't directly run it from here since the caller might be in an * interrupt-protected region. Not all irq controller chips can * retrigger interrupts at the hardware level, so in those cases * we allow the resending of IRQs via a tasklet. */ #include <linux/irq.h> #include <linux/module.h> #include <linux/random.h> #include <linux/interrupt.h> #include "internals.h" #ifdef CONFIG_HARDIRQS_SW_RESEND /* Bitmap to handle software resend of interrupts: */ static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS); /* * Run software resends of IRQ's */ static void resend_irqs(unsigned long arg) { struct irq_desc *desc; int irq; while (!bitmap_empty(irqs_resend, nr_irqs)) { irq = find_first_bit(irqs_resend, nr_irqs); clear_bit(irq, irqs_resend); desc = irq_to_desc(irq); if (!desc) continue; local_irq_disable(); desc->handle_irq(desc); local_irq_enable(); } } /* Tasklet to handle resend: */ static DECLARE_TASKLET_OLD(resend_tasklet, resend_irqs); static int irq_sw_resend(struct irq_desc *desc) { unsigned int irq = irq_desc_get_irq(desc); /* * Validate whether this interrupt can be safely injected from * non interrupt context */ if (handle_enforce_irqctx(&desc->irq_data)) return -EINVAL; /* * If the interrupt is running in the thread context of the parent * irq we need to be careful, because we cannot trigger it * directly. */ if (irq_settings_is_nested_thread(desc)) { /* * If the parent_irq is valid, we retrigger the parent, * otherwise we do nothing. */ if (!desc->parent_irq) return -EINVAL; irq = desc->parent_irq; } /* Set it pending and activate the softirq: */ set_bit(irq, irqs_resend); tasklet_schedule(&resend_tasklet); return 0; } #else static int irq_sw_resend(struct irq_desc *desc) { return -EINVAL; } #endif static int try_retrigger(struct irq_desc *desc) { if (desc->irq_data.chip->irq_retrigger) return desc->irq_data.chip->irq_retrigger(&desc->irq_data); #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY return irq_chip_retrigger_hierarchy(&desc->irq_data); #else return 0; #endif } /* * IRQ resend * * Is called with interrupts disabled and desc->lock held. */ int check_irq_resend(struct irq_desc *desc, bool inject) { int err = 0; /* * We do not resend level type interrupts. Level type interrupts * are resent by hardware when they are still active. Clear the * pending bit so suspend/resume does not get confused. */ if (irq_settings_is_level(desc)) { desc->istate &= ~IRQS_PENDING; return -EINVAL; } if (desc->istate & IRQS_REPLAY) return -EBUSY; if (!(desc->istate & IRQS_PENDING) && !inject) return 0; desc->istate &= ~IRQS_PENDING; if (!try_retrigger(desc)) err = irq_sw_resend(desc); /* If the retrigger was successfull, mark it with the REPLAY bit */ if (!err) desc->istate |= IRQS_REPLAY; return err; } #ifdef CONFIG_GENERIC_IRQ_INJECTION /** * irq_inject_interrupt - Inject an interrupt for testing/error injection * @irq: The interrupt number * * This function must only be used for debug and testing purposes! * * Especially on x86 this can cause a premature completion of an interrupt * affinity change causing the interrupt line to become stale. Very * unlikely, but possible. * * The injection can fail for various reasons: * - Interrupt is not activated * - Interrupt is NMI type or currently replaying * - Interrupt is level type * - Interrupt does not support hardware retrigger and software resend is * either not enabled or not possible for the interrupt. */ int irq_inject_interrupt(unsigned int irq) { struct irq_desc *desc; unsigned long flags; int err; /* Try the state injection hardware interface first */ if (!irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true)) return 0; /* That failed, try via the resend mechanism */ desc = irq_get_desc_buslock(irq, &flags, 0); if (!desc) return -EINVAL; /* * Only try to inject when the interrupt is: * - not NMI type * - activated */ if ((desc->istate & IRQS_NMI) || !irqd_is_activated(&desc->irq_data)) err = -EINVAL; else err = check_irq_resend(desc, true); irq_put_desc_busunlock(desc, flags); return err; } EXPORT_SYMBOL_GPL(irq_inject_interrupt); #endif