[PATCH v6 08/10] irqchip/riscv-imsic: Implement irq_force_complete_move() for IMSIC

[Anup Patel <apatel@ventanamicro.com>]

Implement irq_force_complete_move() for IMSIC driver so that in-flight
vector movements on a CPU can be cleaned-up when the CPU goes down.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
 drivers/irqchip/irq-riscv-imsic-platform.c | 32 ++++++++++++++++++++++
 drivers/irqchip/irq-riscv-imsic-state.c    | 17 ++++++++++++
 drivers/irqchip/irq-riscv-imsic-state.h    |  1 +
 3 files changed, 50 insertions(+)

diff --git a/drivers/irqchip/irq-riscv-imsic-platform.c b/drivers/irqchip/irq-riscv-imsic-platform.c
index 9a5e7b4541f6..b9e3f9030bdf 100644
--- a/drivers/irqchip/irq-riscv-imsic-platform.c
+++ b/drivers/irqchip/irq-riscv-imsic-platform.c
@@ -129,6 +129,37 @@ static int imsic_irq_set_affinity(struct irq_data *d, const struct cpumask *mask
 
 	return IRQ_SET_MASK_OK_DONE;
 }
+
+static void imsic_irq_force_complete_move(struct irq_data *d)
+{
+	struct imsic_vector *mvec, *vec = irq_data_get_irq_chip_data(d);
+	unsigned int cpu = smp_processor_id();
+
+	if (WARN_ON(!vec))
+		return;
+
+	/* Do nothing if there is no in-flight move */
+	mvec = imsic_vector_get_move(vec);
+	if (!mvec)
+		return;
+
+	/* Do nothing if the old IMSIC vector does not belong to current CPU */
+	if (mvec->cpu != cpu)
+		return;
+
+	/*
+	 * The best we can do is force cleanup the old IMSIC vector.
+	 *
+	 * The challenges over here are same as x86 vector domain so
+	 * refer to the comments in irq_force_complete_move() function
+	 * implemented at arch/x86/kernel/apic/vector.c.
+	 */
+
+	/* Force cleanup in-flight move */
+	pr_info("IRQ fixup: irq %d move in progress, old vector cpu %d local_id %d\n",
+		d->irq, mvec->cpu, mvec->local_id);
+	imsic_vector_force_move_cleanup(vec);
+}
 #endif
 
 static struct irq_chip imsic_irq_base_chip = {
@@ -137,6 +168,7 @@ static struct irq_chip imsic_irq_base_chip = {
 	.irq_unmask		= imsic_irq_unmask,
 #ifdef CONFIG_SMP
 	.irq_set_affinity	= imsic_irq_set_affinity,
+	.irq_force_complete_move = imsic_irq_force_complete_move,
 #endif
 	.irq_retrigger		= imsic_irq_retrigger,
 	.irq_compose_msi_msg	= imsic_irq_compose_msg,
diff --git a/drivers/irqchip/irq-riscv-imsic-state.c b/drivers/irqchip/irq-riscv-imsic-state.c
index 96e994443fc7..5ec2b6bdffb2 100644
--- a/drivers/irqchip/irq-riscv-imsic-state.c
+++ b/drivers/irqchip/irq-riscv-imsic-state.c
@@ -311,6 +311,23 @@ void imsic_vector_unmask(struct imsic_vector *vec)
 	raw_spin_unlock(&lpriv->lock);
 }
 
+void imsic_vector_force_move_cleanup(struct imsic_vector *vec)
+{
+	struct imsic_local_priv *lpriv;
+	struct imsic_vector *mvec;
+	unsigned long flags;
+
+	lpriv = per_cpu_ptr(imsic->lpriv, vec->cpu);
+	raw_spin_lock_irqsave(&lpriv->lock, flags);
+
+	mvec = READ_ONCE(vec->move_prev);
+	WRITE_ONCE(vec->move_prev, NULL);
+	if (mvec)
+		imsic_vector_free(mvec);
+
+	raw_spin_unlock_irqrestore(&lpriv->lock, flags);
+}
+
 static bool imsic_vector_move_update(struct imsic_local_priv *lpriv,
 				     struct imsic_vector *vec, bool is_old_vec,
 				     bool new_enable, struct imsic_vector *move_vec)
diff --git a/drivers/irqchip/irq-riscv-imsic-state.h b/drivers/irqchip/irq-riscv-imsic-state.h
index f02842b84ed5..19dea0c77738 100644
--- a/drivers/irqchip/irq-riscv-imsic-state.h
+++ b/drivers/irqchip/irq-riscv-imsic-state.h
@@ -91,6 +91,7 @@ static inline struct imsic_vector *imsic_vector_get_move(struct imsic_vector *ve
 	return READ_ONCE(vec->move_prev);
 }
 
+void imsic_vector_force_move_cleanup(struct imsic_vector *vec);
 void imsic_vector_move(struct imsic_vector *old_vec, struct imsic_vector *new_vec);
 
 struct imsic_vector *imsic_vector_from_local_id(unsigned int cpu, unsigned int local_id);
-- 
2.43.0