[PATCH v2 05/11] genirq: Introduce kconfig option GENERIC_PENDING_IRQ_CHIPFLAGS

[Anup Patel]

From: Thomas Gleixner <tglx at linutronix.de>

Introduce kconfig option GENERIC_PENDING_IRQ_CHIPFLAGS which allows
irq core to set IRQD_MOVE_PCNTXT flag based on IRQCHIP_MOVE_DEFERRED
flag.

This kconfig option will help architectures such as x86 and RISC-V
to mark top-level irqchip instances where irqs can't be moved in
the process context.

Signed-off-by: Thomas Gleixner <tglx at linutronix.de>
Signed-off-by: Anup Patel <apatel at ventanamicro.com>
---
 include/linux/irq.h    | 10 ++++++++++
 kernel/irq/Kconfig     |  4 ++++
 kernel/irq/chip.c      | 39 ++++++++++++++++++++++++++++++++++++---
 kernel/irq/irqdomain.c |  1 +
 4 files changed, 51 insertions(+), 3 deletions(-)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index fa711f80957b..b689c8fe8d60 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -567,6 +567,7 @@ struct irq_chip {
  *                                    in the suspend path if they are in disabled state
  * IRQCHIP_AFFINITY_PRE_STARTUP:      Default affinity update before startup
  * IRQCHIP_IMMUTABLE:		      Don't ever change anything in this chip
+ * IRQCHIP_MOVE_DEFERRED:             Move the interrupt in actual interrupt context
  */
 enum {
 	IRQCHIP_SET_TYPE_MASKED			= (1 <<  0),
@@ -581,6 +582,7 @@ enum {
 	IRQCHIP_ENABLE_WAKEUP_ON_SUSPEND	= (1 <<  9),
 	IRQCHIP_AFFINITY_PRE_STARTUP		= (1 << 10),
 	IRQCHIP_IMMUTABLE			= (1 << 11),
+	IRQCHIP_MOVE_DEFERRED			= (1 << 12),
 };
 
 #include <linux/irqdesc.h>
@@ -634,6 +636,14 @@ static inline void irq_move_masked_irq(struct irq_data *data) { }
 static inline void irq_force_complete_move(struct irq_desc *desc) { }
 #endif
 
+#if defined(CONFIG_GENERIC_PENDING_IRQ_CHIPFLAGS)
+void irq_update_pcntxt_flag(unsigned int irq, const struct irq_chip *chip);
+#else
+static inline void irq_update_pcntxt_flag(unsigned int irq, const struct irq_chip *chip)
+{
+}
+#endif
+
 extern int no_irq_affinity;
 
 #ifdef CONFIG_HARDIRQS_SW_RESEND
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 529adb1f5859..6d85a47fbf41 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -31,6 +31,10 @@ config GENERIC_IRQ_EFFECTIVE_AFF_MASK
 config GENERIC_PENDING_IRQ
 	bool
 
+# Deduce delayed migration from top-level interrupt chip flags
+config GENERIC_PENDING_IRQ_CHIPFLAGS
+	bool
+
 # Support for generic irq migrating off cpu before the cpu is offline.
 config GENERIC_IRQ_MIGRATION
 	bool
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 271e9139de77..623959a24464 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -33,6 +33,33 @@ struct irqaction chained_action = {
 	.handler = bad_chained_irq,
 };
 
+#ifdef CONFIG_GENERIC_PENDING_IRQ_CHIPFLAGS
+static void __irq_update_pcntxt_flag(struct irq_desc *desc,
+				     const struct irq_chip *chip)
+{
+	if (chip) {
+		if (chip->flags & IRQCHIP_MOVE_DEFERRED)
+			irqd_clear(&desc->irq_data, IRQD_MOVE_PCNTXT);
+		else
+			irqd_set(&desc->irq_data, IRQD_MOVE_PCNTXT);
+	}
+}
+
+void irq_update_pcntxt_flag(unsigned int irq, const struct irq_chip *chip)
+{
+	unsigned long flags;
+	struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+
+	__irq_update_pcntxt_flag(desc, chip);
+	irq_put_desc_unlock(desc, flags);
+}
+#else
+static inline void __irq_update_pcntxt_flag(struct irq_desc *desc,
+					    const struct irq_chip *chip)
+{
+}
+#endif
+
 /**
  *	irq_set_chip - set the irq chip for an irq
  *	@irq:	irq number
@@ -47,6 +74,7 @@ int irq_set_chip(unsigned int irq, const struct irq_chip *chip)
 		return -EINVAL;
 
 	desc->irq_data.chip = (struct irq_chip *)(chip ?: &no_irq_chip);
+	__irq_update_pcntxt_flag(desc, chip);
 	irq_put_desc_unlock(desc, flags);
 	/*
 	 * For !CONFIG_SPARSE_IRQ make the irq show up in
@@ -1114,16 +1142,21 @@ void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set)
 	trigger = irqd_get_trigger_type(&desc->irq_data);
 
 	irqd_clear(&desc->irq_data, IRQD_NO_BALANCING | IRQD_PER_CPU |
-		   IRQD_TRIGGER_MASK | IRQD_LEVEL | IRQD_MOVE_PCNTXT);
+		   IRQD_TRIGGER_MASK | IRQD_LEVEL);
 	if (irq_settings_has_no_balance_set(desc))
 		irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
 	if (irq_settings_is_per_cpu(desc))
 		irqd_set(&desc->irq_data, IRQD_PER_CPU);
-	if (irq_settings_can_move_pcntxt(desc))
-		irqd_set(&desc->irq_data, IRQD_MOVE_PCNTXT);
 	if (irq_settings_is_level(desc))
 		irqd_set(&desc->irq_data, IRQD_LEVEL);
 
+	/* Keep this around until x86 is converted over */
+	if (!IS_ENABLED(CONFIG_GENERIC_PENDING_IRQ_CHIPFLAGS)) {
+		irqd_clear(&desc->irq_data, IRQD_MOVE_PCNTXT);
+		if (irq_settings_can_move_pcntxt(desc))
+			irqd_set(&desc->irq_data, IRQD_MOVE_PCNTXT);
+	}
+
 	tmp = irq_settings_get_trigger_mask(desc);
 	if (tmp != IRQ_TYPE_NONE)
 		trigger = tmp;
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index ec6d8e72d980..ec5fc1d8cebe 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1508,6 +1508,7 @@ int irq_domain_set_hwirq_and_chip(struct irq_domain *domain, unsigned int virq,
 	irq_data->hwirq = hwirq;
 	irq_data->chip = (struct irq_chip *)(chip ? chip : &no_irq_chip);
 	irq_data->chip_data = chip_data;
+	irq_update_pcntxt_flag(virq, chip);
 
 	return 0;
 }
-- 
2.43.0