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-rw-r--r--kernel/irq/resend.c184
1 files changed, 184 insertions, 0 deletions
diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
new file mode 100644
index 000000000..8ccd32a0c
--- /dev/null
+++ b/kernel/irq/resend.c
@@ -0,0 +1,184 @@
+// 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