Merge branch 'irq/generic-nmi' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms

* 'irq/generic-nmi' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms:
  irqdesc: Add domain handler for NMIs
  genirq: Provide NMI handlers
  genirq: Provide NMI management for percpu_devid interrupts
  genirq: Provide basic NMI management for interrupt lines

Author: ctmarinas

include/linux/interrupt.h

@@ -156,6 +156,10 @@ __request_percpu_irq(unsigned int irq, irq_handler_t handler,
 		     unsigned long flags, const char *devname,
 		     void __percpu *percpu_dev_id);
 
+extern int __must_check
+request_nmi(unsigned int irq, irq_handler_t handler, unsigned long flags,
+	    const char *name, void *dev);
+
 static inline int __must_check
 request_percpu_irq(unsigned int irq, irq_handler_t handler,
 		   const char *devname, void __percpu *percpu_dev_id)
@@ -164,9 +168,16 @@ request_percpu_irq(unsigned int irq, irq_handler_t handler,
 				    devname, percpu_dev_id);
 }
 
+extern int __must_check
+request_percpu_nmi(unsigned int irq, irq_handler_t handler,
+		   const char *devname, void __percpu *dev);
+
 extern const void *free_irq(unsigned int, void *);
 extern void free_percpu_irq(unsigned int, void __percpu *);
 
+extern const void *free_nmi(unsigned int irq, void *dev_id);
+extern void free_percpu_nmi(unsigned int irq, void __percpu *percpu_dev_id);
+
 struct device;
 
 extern int __must_check
@@ -217,6 +228,13 @@ extern void enable_percpu_irq(unsigned int irq, unsigned int type);
 extern bool irq_percpu_is_enabled(unsigned int irq);
 extern void irq_wake_thread(unsigned int irq, void *dev_id);
 
+extern void disable_nmi_nosync(unsigned int irq);
+extern void disable_percpu_nmi(unsigned int irq);
+extern void enable_nmi(unsigned int irq);
+extern void enable_percpu_nmi(unsigned int irq, unsigned int type);
+extern int prepare_percpu_nmi(unsigned int irq);
+extern void teardown_percpu_nmi(unsigned int irq);
+
 /* The following three functions are for the core kernel use only. */
 extern void suspend_device_irqs(void);
 extern void resume_device_irqs(void);

include/linux/irq.h

@@ -442,6 +442,8 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
  * @irq_set_vcpu_affinity:	optional to target a vCPU in a virtual machine
  * @ipi_send_single:	send a single IPI to destination cpus
  * @ipi_send_mask:	send an IPI to destination cpus in cpumask
+ * @irq_nmi_setup:	function called from core code before enabling an NMI
+ * @irq_nmi_teardown:	function called from core code after disabling an NMI
  * @flags:		chip specific flags
  */
 struct irq_chip {
@@ -490,6 +492,9 @@ struct irq_chip {
 	void		(*ipi_send_single)(struct irq_data *data, unsigned int cpu);
 	void		(*ipi_send_mask)(struct irq_data *data, const struct cpumask *dest);
 
+	int		(*irq_nmi_setup)(struct irq_data *data);
+	void		(*irq_nmi_teardown)(struct irq_data *data);
+
 	unsigned long	flags;
 };
 
@@ -505,6 +510,7 @@ struct irq_chip {
  * IRQCHIP_ONESHOT_SAFE:	One shot does not require mask/unmask
  * IRQCHIP_EOI_THREADED:	Chip requires eoi() on unmask in threaded mode
  * IRQCHIP_SUPPORTS_LEVEL_MSI	Chip can provide two doorbells for Level MSIs
+ * IRQCHIP_SUPPORTS_NMI:	Chip can deliver NMIs, only for root irqchips
  */
 enum {
 	IRQCHIP_SET_TYPE_MASKED		= (1 <<  0),
@@ -515,6 +521,7 @@ enum {
 	IRQCHIP_ONESHOT_SAFE		= (1 <<  5),
 	IRQCHIP_EOI_THREADED		= (1 <<  6),
 	IRQCHIP_SUPPORTS_LEVEL_MSI	= (1 <<  7),
+	IRQCHIP_SUPPORTS_NMI		= (1 <<  8),
 };
 
 #include <linux/irqdesc.h>
@@ -594,6 +601,9 @@ extern void handle_percpu_devid_irq(struct irq_desc *desc);
 extern void handle_bad_irq(struct irq_desc *desc);
 extern void handle_nested_irq(unsigned int irq);
 
+extern void handle_fasteoi_nmi(struct irq_desc *desc);
+extern void handle_percpu_devid_fasteoi_nmi(struct irq_desc *desc);
+
 extern int irq_chip_compose_msi_msg(struct irq_data *data, struct msi_msg *msg);
 extern int irq_chip_pm_get(struct irq_data *data);
 extern int irq_chip_pm_put(struct irq_data *data);

include/linux/irqdesc.h

@@ -171,6 +171,11 @@ static inline int handle_domain_irq(struct irq_domain *domain,
 {
 	return __handle_domain_irq(domain, hwirq, true, regs);
 }
+
+#ifdef CONFIG_IRQ_DOMAIN
+int handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq,
+		      struct pt_regs *regs);
+#endif
 #endif
 
 /* Test to see if a driver has successfully requested an irq */

kernel/irq/chip.c

@@ -729,6 +729,37 @@ void handle_fasteoi_irq(struct irq_desc *desc)
 }
 EXPORT_SYMBOL_GPL(handle_fasteoi_irq);
 
+/**
+ *	handle_fasteoi_nmi - irq handler for NMI interrupt lines
+ *	@desc:	the interrupt description structure for this irq
+ *
+ *	A simple NMI-safe handler, considering the restrictions
+ *	from request_nmi.
+ *
+ *	Only a single callback will be issued to the chip: an ->eoi()
+ *	call when the interrupt has been serviced. This enables support
+ *	for modern forms of interrupt handlers, which handle the flow
+ *	details in hardware, transparently.
+ */
+void handle_fasteoi_nmi(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct irqaction *action = desc->action;
+	unsigned int irq = irq_desc_get_irq(desc);
+	irqreturn_t res;
+
+	trace_irq_handler_entry(irq, action);
+	/*
+	 * NMIs cannot be shared, there is only one action.
+	 */
+	res = action->handler(irq, action->dev_id);
+	trace_irq_handler_exit(irq, action, res);
+
+	if (chip->irq_eoi)
+		chip->irq_eoi(&desc->irq_data);
+}
+EXPORT_SYMBOL_GPL(handle_fasteoi_nmi);
+
 /**
  *	handle_edge_irq - edge type IRQ handler
  *	@desc:	the interrupt description structure for this irq
@@ -908,6 +939,29 @@ void handle_percpu_devid_irq(struct irq_desc *desc)
 		chip->irq_eoi(&desc->irq_data);
 }
 
+/**
+ * handle_percpu_devid_fasteoi_nmi - Per CPU local NMI handler with per cpu
+ *				     dev ids
+ * @desc:	the interrupt description structure for this irq
+ *
+ * Similar to handle_fasteoi_nmi, but handling the dev_id cookie
+ * as a percpu pointer.
+ */
+void handle_percpu_devid_fasteoi_nmi(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	struct irqaction *action = desc->action;
+	unsigned int irq = irq_desc_get_irq(desc);
+	irqreturn_t res;
+
+	trace_irq_handler_entry(irq, action);
+	res = action->handler(irq, raw_cpu_ptr(action->percpu_dev_id));
+	trace_irq_handler_exit(irq, action, res);
+
+	if (chip->irq_eoi)
+		chip->irq_eoi(&desc->irq_data);
+}
+
 static void
 __irq_do_set_handler(struct irq_desc *desc, irq_flow_handler_t handle,
 		     int is_chained, const char *name)

kernel/irq/debugfs.c

@@ -56,6 +56,7 @@ static const struct irq_bit_descr irqchip_flags[] = {
 	BIT_MASK_DESCR(IRQCHIP_ONESHOT_SAFE),
 	BIT_MASK_DESCR(IRQCHIP_EOI_THREADED),
 	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_LEVEL_MSI),
+	BIT_MASK_DESCR(IRQCHIP_SUPPORTS_NMI),
 };
 
 static void
@@ -140,6 +141,7 @@ static const struct irq_bit_descr irqdesc_istates[] = {
 	BIT_MASK_DESCR(IRQS_WAITING),
 	BIT_MASK_DESCR(IRQS_PENDING),
 	BIT_MASK_DESCR(IRQS_SUSPENDED),
+	BIT_MASK_DESCR(IRQS_NMI),
 };
 
 
@@ -203,8 +205,8 @@ static ssize_t irq_debug_write(struct file *file, const char __user *user_buf,
 		chip_bus_lock(desc);
 		raw_spin_lock_irqsave(&desc->lock, flags);
 
-		if (irq_settings_is_level(desc)) {
-			/* Can't do level, sorry */
+		if (irq_settings_is_level(desc) || desc->istate & IRQS_NMI) {
+			/* Can't do level nor NMIs, sorry */
 			err = -EINVAL;
 		} else {
 			desc->istate |= IRQS_PENDING;

kernel/irq/internals.h

@@ -49,6 +49,7 @@ enum {
  * IRQS_WAITING			- irq is waiting
  * IRQS_PENDING			- irq is pending and replayed later
  * IRQS_SUSPENDED		- irq is suspended
+ * IRQS_NMI			- irq line is used to deliver NMIs
  */
 enum {
 	IRQS_AUTODETECT		= 0x00000001,
@@ -60,6 +61,7 @@ enum {
 	IRQS_PENDING		= 0x00000200,
 	IRQS_SUSPENDED		= 0x00000800,
 	IRQS_TIMINGS		= 0x00001000,
+	IRQS_NMI		= 0x00002000,
 };
 
 #include "debug.h"

kernel/irq/irqdesc.c

@@ -669,6 +669,41 @@ int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
 	set_irq_regs(old_regs);
 	return ret;
 }
+
+#ifdef CONFIG_IRQ_DOMAIN
+/**
+ * handle_domain_nmi - Invoke the handler for a HW irq belonging to a domain
+ * @domain:	The domain where to perform the lookup
+ * @hwirq:	The HW irq number to convert to a logical one
+ * @regs:	Register file coming from the low-level handling code
+ *
+ * Returns:	0 on success, or -EINVAL if conversion has failed
+ */
+int handle_domain_nmi(struct irq_domain *domain, unsigned int hwirq,
+		      struct pt_regs *regs)
+{
+	struct pt_regs *old_regs = set_irq_regs(regs);
+	unsigned int irq;
+	int ret = 0;
+
+	nmi_enter();
+
+	irq = irq_find_mapping(domain, hwirq);
+
+	/*
+	 * ack_bad_irq is not NMI-safe, just report
+	 * an invalid interrupt.
+	 */
+	if (likely(irq))
+		generic_handle_irq(irq);
+	else
+		ret = -EINVAL;
+
+	nmi_exit();
+	set_irq_regs(old_regs);
+	return ret;
+}
+#endif
 #endif
 
 /* Dynamic interrupt handling */