1 files changed, 144 insertions, 41 deletions

diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
index 9065107f083e..ca9cc1b806a9 100644
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -1,6 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
- * linux/kernel/irq/resend.c
- *
  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
  * Copyright (C) 2005-2006, Thomas Gleixner
  *
@@ -22,70 +21,174 @@
 
 #ifdef CONFIG_HARDIRQS_SW_RESEND
 
-/* Bitmap to handle software resend of interrupts: */
-static DECLARE_BITMAP(irqs_resend, IRQ_BITMAP_BITS);
+/* hlist_head to handle software resend of interrupts: */
+static HLIST_HEAD(irq_resend_list);
+static DEFINE_RAW_SPINLOCK(irq_resend_lock);
 
 /*
  * Run software resends of IRQ's
  */
-static void resend_irqs(unsigned long arg)
+static void resend_irqs(struct tasklet_struct *unused)
 {
-	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);
-		local_irq_disable();
-		desc->handle_irq(irq, desc);
-		local_irq_enable();
+	guard(raw_spinlock_irq)(&irq_resend_lock);
+	while (!hlist_empty(&irq_resend_list)) {
+		struct irq_desc *desc;
+
+		desc = hlist_entry(irq_resend_list.first, struct irq_desc,  resend_node);
+		hlist_del_init(&desc->resend_node);
+
+		raw_spin_unlock(&irq_resend_lock);
+		desc->handle_irq(desc);
+		raw_spin_lock(&irq_resend_lock);
 	}
 }
 
 /* Tasklet to handle resend: */
-static DECLARE_TASKLET(resend_tasklet, resend_irqs, 0);
+static DECLARE_TASKLET(resend_tasklet, resend_irqs);
+
+static int irq_sw_resend(struct irq_desc *desc)
+{
+	/*
+	 * Validate whether this interrupt can be safely injected from
+	 * non interrupt context
+	 */
+	if (irqd_is_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;
+
+		desc = irq_to_desc(desc->parent_irq);
+		if (!desc)
+			return -EINVAL;
+	}
 
+	/* Add to resend_list and activate the softirq: */
+	scoped_guard(raw_spinlock, &irq_resend_lock) {
+		if (hlist_unhashed(&desc->resend_node))
+			hlist_add_head(&desc->resend_node, &irq_resend_list);
+	}
+	tasklet_schedule(&resend_tasklet);
+	return 0;
+}
+
+void clear_irq_resend(struct irq_desc *desc)
+{
+	guard(raw_spinlock)(&irq_resend_lock);
+	hlist_del_init(&desc->resend_node);
+}
+
+void irq_resend_init(struct irq_desc *desc)
+{
+	INIT_HLIST_NODE(&desc->resend_node);
+}
+#else
+void clear_irq_resend(struct irq_desc *desc) {}
+void irq_resend_init(struct irq_desc *desc) {}
+
+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.
  */
-void check_irq_resend(struct irq_desc *desc, unsigned int irq)
+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.
+	 * 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;
+		return -EINVAL;
 	}
+
 	if (desc->istate & IRQS_REPLAY)
-		return;
-	if (desc->istate & IRQS_PENDING) {
-		desc->istate &= ~IRQS_PENDING;
+		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 successful, mark it with the REPLAY bit */
+	if (!err)
 		desc->istate |= IRQS_REPLAY;
+	return err;
+}
 
-		if (!desc->irq_data.chip->irq_retrigger ||
-		    !desc->irq_data.chip->irq_retrigger(&desc->irq_data)) {
-#ifdef CONFIG_HARDIRQS_SW_RESEND
-			/*
-			 * If the interrupt has a parent irq and runs
-			 * in the thread context of the parent irq,
-			 * retrigger the parent.
-			 */
-			if (desc->parent_irq &&
-			    irq_settings_is_nested_thread(desc))
-				irq = desc->parent_irq;
-			/* Set it pending and activate the softirq: */
-			set_bit(irq, irqs_resend);
-			tasklet_schedule(&resend_tasklet);
-#endif
-		}
+#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)
+{
+	int err = -EINVAL;
+
+	/* 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 */
+	scoped_irqdesc_get_and_buslock(irq, 0) {
+		struct irq_desc *desc = scoped_irqdesc;
+
+		/*
+		 * Only try to inject when the interrupt is:
+		 *  - not NMI type
+		 *  - activated
+		 */
+		if (!irq_is_nmi(desc) && irqd_is_activated(&desc->irq_data))
+			err = check_irq_resend(desc, true);
 	}
+	return err;
 }
+EXPORT_SYMBOL_GPL(irq_inject_interrupt);
+#endif