Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 202 insertions, 0 deletions

diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
new file mode 100644
index 0000000000..5f2c66860a
--- /dev/null
+++ b/kernel/irq/resend.c
@@ -0,0 +1,202 @@
+// 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
+
+/* 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(struct tasklet_struct *unused)
+{
+	struct irq_desc *desc;
+
+	raw_spin_lock_irq(&irq_resend_lock);
+	while (!hlist_empty(&irq_resend_list)) {
+		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);
+	}
+	raw_spin_unlock_irq(&irq_resend_lock);
+}
+
+/* Tasklet to handle resend: */
+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 (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: */
+	raw_spin_lock(&irq_resend_lock);
+	if (hlist_unhashed(&desc->resend_node))
+		hlist_add_head(&desc->resend_node, &irq_resend_list);
+	raw_spin_unlock(&irq_resend_lock);
+	tasklet_schedule(&resend_tasklet);
+	return 0;
+}
+
+void clear_irq_resend(struct irq_desc *desc)
+{
+	raw_spin_lock(&irq_resend_lock);
+	hlist_del_init(&desc->resend_node);
+	raw_spin_unlock(&irq_resend_lock);
+}
+
+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.
+ */
+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 successful, 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