7 files changed, 80 insertions, 20 deletions

diff --git a/kernel/irq/debug.h b/kernel/irq/debug.h
index 17f05ef8f575..e4d3819a91cc 100644
--- a/kernel/irq/debug.h
+++ b/kernel/irq/debug.h
@@ -12,6 +12,11 @@
 
 static inline void print_irq_desc(unsigned int irq, struct irq_desc *desc)
 {
+	static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 5);
+
+	if (!__ratelimit(&ratelimit))
+		return;
+
 	printk("irq %d, desc: %p, depth: %d, count: %d, unhandled: %d\n",
 		irq, desc, desc->depth, desc->irq_count, desc->irqs_unhandled);
 	printk("->handle_irq():  %p, ", desc->handle_irq);
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
index 7f608ac39653..acfaaef8672a 100644
--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -113,6 +113,7 @@ static const struct irq_bit_descr irqdata_states[] = {
 	BIT_MASK_DESCR(IRQD_SETAFFINITY_PENDING),
 	BIT_MASK_DESCR(IRQD_AFFINITY_MANAGED),
 	BIT_MASK_DESCR(IRQD_MANAGED_SHUTDOWN),
+	BIT_MASK_DESCR(IRQD_CAN_RESERVE),
 
 	BIT_MASK_DESCR(IRQD_FORWARDED_TO_VCPU),
 
diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
index c26c5bb6b491..508c03dfef25 100644
--- a/kernel/irq/generic-chip.c
+++ b/kernel/irq/generic-chip.c
@@ -364,10 +364,11 @@ irq_get_domain_generic_chip(struct irq_domain *d, unsigned int hw_irq)
 EXPORT_SYMBOL_GPL(irq_get_domain_generic_chip);
 
 /*
- * Separate lockdep class for interrupt chip which can nest irq_desc
- * lock.
+ * Separate lockdep classes for interrupt chip which can nest irq_desc
+ * lock and request mutex.
  */
 static struct lock_class_key irq_nested_lock_class;
+static struct lock_class_key irq_nested_request_class;
 
 /*
  * irq_map_generic_chip - Map a generic chip for an irq domain
@@ -409,7 +410,8 @@ int irq_map_generic_chip(struct irq_domain *d, unsigned int virq,
 	set_bit(idx, &gc->installed);
 
 	if (dgc->gc_flags & IRQ_GC_INIT_NESTED_LOCK)
-		irq_set_lockdep_class(virq, &irq_nested_lock_class);
+		irq_set_lockdep_class(virq, &irq_nested_lock_class,
+				      &irq_nested_request_class);
 
 	if (chip->irq_calc_mask)
 		chip->irq_calc_mask(data);
@@ -479,7 +481,8 @@ void irq_setup_generic_chip(struct irq_chip_generic *gc, u32 msk,
 			continue;
 
 		if (flags & IRQ_GC_INIT_NESTED_LOCK)
-			irq_set_lockdep_class(i, &irq_nested_lock_class);
+			irq_set_lockdep_class(i, &irq_nested_lock_class,
+					      &irq_nested_request_class);
 
 		if (!(flags & IRQ_GC_NO_MASK)) {
 			struct irq_data *d = irq_get_irq_data(i);
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 07d08ca701ec..ab19371eab9b 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -440,7 +440,7 @@ static inline bool irq_fixup_move_pending(struct irq_desc *desc, bool fclear)
 #endif /* !CONFIG_GENERIC_PENDING_IRQ */
 
 #if !defined(CONFIG_IRQ_DOMAIN) || !defined(CONFIG_IRQ_DOMAIN_HIERARCHY)
-static inline int irq_domain_activate_irq(struct irq_data *data, bool early)
+static inline int irq_domain_activate_irq(struct irq_data *data, bool reserve)
 {
 	irqd_set_activated(data);
 	return 0;
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 4f4f60015e8a..62068ad46930 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1693,7 +1693,7 @@ static void __irq_domain_deactivate_irq(struct irq_data *irq_data)
 	}
 }
 
-static int __irq_domain_activate_irq(struct irq_data *irqd, bool early)
+static int __irq_domain_activate_irq(struct irq_data *irqd, bool reserve)
 {
 	int ret = 0;
 
@@ -1702,9 +1702,9 @@ static int __irq_domain_activate_irq(struct irq_data *irqd, bool early)
 
 		if (irqd->parent_data)
 			ret = __irq_domain_activate_irq(irqd->parent_data,
-							early);
+							reserve);
 		if (!ret && domain->ops->activate) {
-			ret = domain->ops->activate(domain, irqd, early);
+			ret = domain->ops->activate(domain, irqd, reserve);
 			/* Rollback in case of error */
 			if (ret && irqd->parent_data)
 				__irq_domain_deactivate_irq(irqd->parent_data);
@@ -1716,17 +1716,18 @@ static int __irq_domain_activate_irq(struct irq_data *irqd, bool early)
 /**
  * irq_domain_activate_irq - Call domain_ops->activate recursively to activate
  *			     interrupt
- * @irq_data:	outermost irq_data associated with interrupt
+ * @irq_data:	Outermost irq_data associated with interrupt
+ * @reserve:	If set only reserve an interrupt vector instead of assigning one
  *
  * This is the second step to call domain_ops->activate to program interrupt
  * controllers, so the interrupt could actually get delivered.
  */
-int irq_domain_activate_irq(struct irq_data *irq_data, bool early)
+int irq_domain_activate_irq(struct irq_data *irq_data, bool reserve)
 {
 	int ret = 0;
 
 	if (!irqd_is_activated(irq_data))
-		ret = __irq_domain_activate_irq(irq_data, early);
+		ret = __irq_domain_activate_irq(irq_data, reserve);
 	if (!ret)
 		irqd_set_activated(irq_data);
 	return ret;
diff --git a/kernel/irq/matrix.c b/kernel/irq/matrix.c
index 7df2480005f8..0ba0dd8863a7 100644
--- a/kernel/irq/matrix.c
+++ b/kernel/irq/matrix.c
@@ -384,7 +384,9 @@ unsigned int irq_matrix_available(struct irq_matrix *m, bool cpudown)
 {
 	struct cpumap *cm = this_cpu_ptr(m->maps);
 
-	return (m->global_available - cpudown) ? cm->available : 0;
+	if (!cpudown)
+		return m->global_available;
+	return m->global_available - cm->available;
 }
 
 /**
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index edb987b2c58d..2f3c4f5382cc 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -339,6 +339,40 @@ int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
 	return ret;
 }
 
+/*
+ * Carefully check whether the device can use reservation mode. If
+ * reservation mode is enabled then the early activation will assign a
+ * dummy vector to the device. If the PCI/MSI device does not support
+ * masking of the entry then this can result in spurious interrupts when
+ * the device driver is not absolutely careful. But even then a malfunction
+ * of the hardware could result in a spurious interrupt on the dummy vector
+ * and render the device unusable. If the entry can be masked then the core
+ * logic will prevent the spurious interrupt and reservation mode can be
+ * used. For now reservation mode is restricted to PCI/MSI.
+ */
+static bool msi_check_reservation_mode(struct irq_domain *domain,
+				       struct msi_domain_info *info,
+				       struct device *dev)
+{
+	struct msi_desc *desc;
+
+	if (domain->bus_token != DOMAIN_BUS_PCI_MSI)
+		return false;
+
+	if (!(info->flags & MSI_FLAG_MUST_REACTIVATE))
+		return false;
+
+	if (IS_ENABLED(CONFIG_PCI_MSI) && pci_msi_ignore_mask)
+		return false;
+
+	/*
+	 * Checking the first MSI descriptor is sufficient. MSIX supports
+	 * masking and MSI does so when the maskbit is set.
+	 */
+	desc = first_msi_entry(dev);
+	return desc->msi_attrib.is_msix || desc->msi_attrib.maskbit;
+}
+
 /**
  * msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain
  * @domain:	The domain to allocate from
@@ -353,9 +387,11 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 {
 	struct msi_domain_info *info = domain->host_data;
 	struct msi_domain_ops *ops = info->ops;
-	msi_alloc_info_t arg;
+	struct irq_data *irq_data;
 	struct msi_desc *desc;
+	msi_alloc_info_t arg;
 	int i, ret, virq;
+	bool can_reserve;
 
 	ret = msi_domain_prepare_irqs(domain, dev, nvec, &arg);
 	if (ret)
@@ -385,6 +421,8 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 	if (ops->msi_finish)
 		ops->msi_finish(&arg, 0);
 
+	can_reserve = msi_check_reservation_mode(domain, info, dev);
+
 	for_each_msi_entry(desc, dev) {
 		virq = desc->irq;
 		if (desc->nvec_used == 1)
@@ -397,15 +435,25 @@ int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 		 * the MSI entries before the PCI layer enables MSI in the
 		 * card. Otherwise the card latches a random msi message.
 		 */
-		if (info->flags & MSI_FLAG_ACTIVATE_EARLY) {
-			struct irq_data *irq_data;
+		if (!(info->flags & MSI_FLAG_ACTIVATE_EARLY))
+			continue;
 
+		irq_data = irq_domain_get_irq_data(domain, desc->irq);
+		if (!can_reserve)
+			irqd_clr_can_reserve(irq_data);
+		ret = irq_domain_activate_irq(irq_data, can_reserve);
+		if (ret)
+			goto cleanup;
+	}
+
+	/*
+	 * If these interrupts use reservation mode, clear the activated bit
+	 * so request_irq() will assign the final vector.
+	 */
+	if (can_reserve) {
+		for_each_msi_entry(desc, dev) {
 			irq_data = irq_domain_get_irq_data(domain, desc->irq);
-			ret = irq_domain_activate_irq(irq_data, true);
-			if (ret)
-				goto cleanup;
-			if (info->flags & MSI_FLAG_MUST_REACTIVATE)
-				irqd_clr_activated(irq_data);
+			irqd_clr_activated(irq_data);
 		}
 	}
 	return 0;