1 files changed, 405 insertions, 1 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 84b54a17b95d..9ec34a2a6638 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -341,7 +341,7 @@ irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
         /* The release function is promised process context */
         might_sleep();
 
-        if (!desc)
+        if (!desc || desc->istate & IRQS_NMI)
                 return -EINVAL;
 
         /* Complete initialisation of *notify */
@@ -553,6 +553,21 @@ bool disable_hardirq(unsigned int irq)
 }
 EXPORT_SYMBOL_GPL(disable_hardirq);
 
+/**
+ *      disable_nmi_nosync - disable an nmi without waiting
+ *      @irq: Interrupt to disable
+ *
+ *      Disable the selected interrupt line. Disables and enables are
+ *      nested.
+ *      The interrupt to disable must have been requested through request_nmi.
+ *      Unlike disable_nmi(), this function does not ensure existing
+ *      instances of the IRQ handler have completed before returning.
+ */
+void disable_nmi_nosync(unsigned int irq)
+{
+        disable_irq_nosync(irq);
+}
+
 void __enable_irq(struct irq_desc *desc)
 {
         switch (desc->depth) {
@@ -609,6 +624,20 @@ out:
 }
 EXPORT_SYMBOL(enable_irq);
 
+/**
+ *      enable_nmi - enable handling of an nmi
+ *      @irq: Interrupt to enable
+ *
+ *      The interrupt to enable must have been requested through request_nmi.
+ *      Undoes the effect of one call to disable_nmi(). If this
+ *      matches the last disable, processing of interrupts on this
+ *      IRQ line is re-enabled.
+ */
+void enable_nmi(unsigned int irq)
+{
+        enable_irq(irq);
+}
+
 static int set_irq_wake_real(unsigned int irq, unsigned int on)
 {
         struct irq_desc *desc = irq_to_desc(irq);
@@ -644,6 +673,12 @@ int irq_set_irq_wake(unsigned int irq, unsigned int on)
         if (!desc)
                 return -EINVAL;
 
+        /* Don't use NMIs as wake up interrupts please */
+        if (desc->istate & IRQS_NMI) {
+                ret = -EINVAL;
+                goto out_unlock;
+        }
+
         /* wakeup-capable irqs can be shared between drivers that
          * don't need to have the same sleep mode behaviors.
          */
@@ -666,6 +701,8 @@ int irq_set_irq_wake(unsigned int irq, unsigned int on)
                                 irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
                 }
         }
+
+out_unlock:
         irq_put_desc_busunlock(desc, flags);
         return ret;
 }
@@ -726,6 +763,7 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned long flags)
         case IRQ_SET_MASK_OK_DONE:
                 irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
                 irqd_set(&desc->irq_data, flags);
+                /* fall through */
 
         case IRQ_SET_MASK_OK_NOCOPY:
                 flags = irqd_get_trigger_type(&desc->irq_data);
@@ -1128,6 +1166,39 @@ static void irq_release_resources(struct irq_desc *desc)
                 c->irq_release_resources(d);
 }
 
+static bool irq_supports_nmi(struct irq_desc *desc)
+{
+        struct irq_data *d = irq_desc_get_irq_data(desc);
+
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+        /* Only IRQs directly managed by the root irqchip can be set as NMI */
+        if (d->parent_data)
+                return false;
+#endif
+        /* Don't support NMIs for chips behind a slow bus */
+        if (d->chip->irq_bus_lock || d->chip->irq_bus_sync_unlock)
+                return false;
+
+        return d->chip->flags & IRQCHIP_SUPPORTS_NMI;
+}
+
+static int irq_nmi_setup(struct irq_desc *desc)
+{
+        struct irq_data *d = irq_desc_get_irq_data(desc);
+        struct irq_chip *c = d->chip;
+
+        return c->irq_nmi_setup ? c->irq_nmi_setup(d) : -EINVAL;
+}
+
+static void irq_nmi_teardown(struct irq_desc *desc)
+{
+        struct irq_data *d = irq_desc_get_irq_data(desc);
+        struct irq_chip *c = d->chip;
+
+        if (c->irq_nmi_teardown)
+                c->irq_nmi_teardown(d);
+}
+
 static int
 setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
 {
@@ -1302,9 +1373,17 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                  * fields must have IRQF_SHARED set and the bits which
                  * set the trigger type must match. Also all must
                  * agree on ONESHOT.
+                 * Interrupt lines used for NMIs cannot be shared.
                  */
                 unsigned int oldtype;
 
+                if (desc->istate & IRQS_NMI) {
+                        pr_err("Invalid attempt to share NMI for %s (irq %d) on irqchip %s.\n",
+                                new->name, irq, desc->irq_data.chip->name);
+                        ret = -EINVAL;
+                        goto out_unlock;
+                }
+
                 /*
                  * If nobody did set the configuration before, inherit
                  * the one provided by the requester.
@@ -1756,6 +1835,59 @@ const void *free_irq(unsigned int irq, void *dev_id)
 }
 EXPORT_SYMBOL(free_irq);
 
+/* This function must be called with desc->lock held */
+static const void *__cleanup_nmi(unsigned int irq, struct irq_desc *desc)
+{
+        const char *devname = NULL;
+
+        desc->istate &= ~IRQS_NMI;
+
+        if (!WARN_ON(desc->action == NULL)) {
+                irq_pm_remove_action(desc, desc->action);
+                devname = desc->action->name;
+                unregister_handler_proc(irq, desc->action);
+
+                kfree(desc->action);
+                desc->action = NULL;
+        }
+
+        irq_settings_clr_disable_unlazy(desc);
+        irq_shutdown(desc);
+
+        irq_release_resources(desc);
+
+        irq_chip_pm_put(&desc->irq_data);
+        module_put(desc->owner);
+
+        return devname;
+}
+
+const void *free_nmi(unsigned int irq, void *dev_id)
+{
+        struct irq_desc *desc = irq_to_desc(irq);
+        unsigned long flags;
+        const void *devname;
+
+        if (!desc || WARN_ON(!(desc->istate & IRQS_NMI)))
+                return NULL;
+
+        if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+                return NULL;
+
+        /* NMI still enabled */
+        if (WARN_ON(desc->depth == 0))
+                disable_nmi_nosync(irq);
+
+        raw_spin_lock_irqsave(&desc->lock, flags);
+
+        irq_nmi_teardown(desc);
+        devname = __cleanup_nmi(irq, desc);
+
+        raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+        return devname;
+}
+
 /**
  *      request_threaded_irq - allocate an interrupt line
  *      @irq: Interrupt line to allocate
@@ -1925,6 +2057,101 @@ int request_any_context_irq(unsigned int irq, irq_handler_t handler,
 }
 EXPORT_SYMBOL_GPL(request_any_context_irq);
 
+/**
+ *      request_nmi - allocate an interrupt line for NMI delivery
+ *      @irq: Interrupt line to allocate
+ *      @handler: Function to be called when the IRQ occurs.
+ *                Threaded handler for threaded interrupts.
+ *      @irqflags: Interrupt type flags
+ *      @name: An ascii name for the claiming device
+ *      @dev_id: A cookie passed back to the handler function
+ *
+ *      This call allocates interrupt resources and enables the
+ *      interrupt line and IRQ handling. It sets up the IRQ line
+ *      to be handled as an NMI.
+ *
+ *      An interrupt line delivering NMIs cannot be shared and IRQ handling
+ *      cannot be threaded.
+ *
+ *      Interrupt lines requested for NMI delivering must produce per cpu
+ *      interrupts and have auto enabling setting disabled.
+ *
+ *      Dev_id must be globally unique. Normally the address of the
+ *      device data structure is used as the cookie. Since the handler
+ *      receives this value it makes sense to use it.
+ *
+ *      If the interrupt line cannot be used to deliver NMIs, function
+ *      will fail and return a negative value.
+ */
+int request_nmi(unsigned int irq, irq_handler_t handler,
+                unsigned long irqflags, const char *name, void *dev_id)
+{
+        struct irqaction *action;
+        struct irq_desc *desc;
+        unsigned long flags;
+        int retval;
+
+        if (irq == IRQ_NOTCONNECTED)
+                return -ENOTCONN;
+
+        /* NMI cannot be shared, used for Polling */
+        if (irqflags & (IRQF_SHARED | IRQF_COND_SUSPEND | IRQF_IRQPOLL))
+                return -EINVAL;
+
+        if (!(irqflags & IRQF_PERCPU))
+                return -EINVAL;
+
+        if (!handler)
+                return -EINVAL;
+
+        desc = irq_to_desc(irq);
+
+        if (!desc || irq_settings_can_autoenable(desc) ||
+            !irq_settings_can_request(desc) ||
+            WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||
+            !irq_supports_nmi(desc))
+                return -EINVAL;
+
+        action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+        if (!action)
+                return -ENOMEM;
+
+        action->handler = handler;
+        action->flags = irqflags | IRQF_NO_THREAD | IRQF_NOBALANCING;
+        action->name = name;
+        action->dev_id = dev_id;
+
+        retval = irq_chip_pm_get(&desc->irq_data);
+        if (retval < 0)
+                goto err_out;
+
+        retval = __setup_irq(irq, desc, action);
+        if (retval)
+                goto err_irq_setup;
+
+        raw_spin_lock_irqsave(&desc->lock, flags);
+
+        /* Setup NMI state */
+        desc->istate |= IRQS_NMI;
+        retval = irq_nmi_setup(desc);
+        if (retval) {
+                __cleanup_nmi(irq, desc);
+                raw_spin_unlock_irqrestore(&desc->lock, flags);
+                return -EINVAL;
+        }
+
+        raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+        return 0;
+
+err_irq_setup:
+        irq_chip_pm_put(&desc->irq_data);
+err_out:
+        kfree(action);
+
+        return retval;
+}
+
 void enable_percpu_irq(unsigned int irq, unsigned int type)
 {
         unsigned int cpu = smp_processor_id();
@@ -1959,6 +2186,11 @@ out:
 }
 EXPORT_SYMBOL_GPL(enable_percpu_irq);
 
+void enable_percpu_nmi(unsigned int irq, unsigned int type)
+{
+        enable_percpu_irq(irq, type);
+}
+
 /**
  * irq_percpu_is_enabled - Check whether the per cpu irq is enabled
  * @irq:        Linux irq number to check for
@@ -1998,6 +2230,11 @@ void disable_percpu_irq(unsigned int irq)
 }
 EXPORT_SYMBOL_GPL(disable_percpu_irq);
 
+void disable_percpu_nmi(unsigned int irq)
+{
+        disable_percpu_irq(irq);
+}
+
 /*
  * Internal function to unregister a percpu irqaction.
  */
@@ -2029,6 +2266,8 @@ static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_
         /* Found it - now remove it from the list of entries: */
         desc->action = NULL;
 
+        desc->istate &= ~IRQS_NMI;
+
         raw_spin_unlock_irqrestore(&desc->lock, flags);
 
         unregister_handler_proc(irq, action);
@@ -2082,6 +2321,19 @@ void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
 }
 EXPORT_SYMBOL_GPL(free_percpu_irq);
 
+void free_percpu_nmi(unsigned int irq, void __percpu *dev_id)
+{
+        struct irq_desc *desc = irq_to_desc(irq);
+
+        if (!desc || !irq_settings_is_per_cpu_devid(desc))
+                return;
+
+        if (WARN_ON(!(desc->istate & IRQS_NMI)))
+                return;
+
+        kfree(__free_percpu_irq(irq, dev_id));
+}
+
 /**
  *      setup_percpu_irq - setup a per-cpu interrupt
  *      @irq: Interrupt line to setup
@@ -2172,6 +2424,158 @@ int __request_percpu_irq(unsigned int irq, irq_handler_t handler,
 EXPORT_SYMBOL_GPL(__request_percpu_irq);
 
 /**
+ *      request_percpu_nmi - allocate a percpu interrupt line for NMI delivery
+ *      @irq: Interrupt line to allocate
+ *      @handler: Function to be called when the IRQ occurs.
+ *      @name: An ascii name for the claiming device
+ *      @dev_id: A percpu cookie passed back to the handler function
+ *
+ *      This call allocates interrupt resources for a per CPU NMI. Per CPU NMIs
+ *      have to be setup on each CPU by calling prepare_percpu_nmi() before
+ *      being enabled on the same CPU by using enable_percpu_nmi().
+ *
+ *      Dev_id must be globally unique. It is a per-cpu variable, and
+ *      the handler gets called with the interrupted CPU's instance of
+ *      that variable.
+ *
+ *      Interrupt lines requested for NMI delivering should have auto enabling
+ *      setting disabled.
+ *
+ *      If the interrupt line cannot be used to deliver NMIs, function
+ *      will fail returning a negative value.
+ */
+int request_percpu_nmi(unsigned int irq, irq_handler_t handler,
+                       const char *name, void __percpu *dev_id)
+{
+        struct irqaction *action;
+        struct irq_desc *desc;
+        unsigned long flags;
+        int retval;
+
+        if (!handler)
+                return -EINVAL;
+
+        desc = irq_to_desc(irq);
+
+        if (!desc || !irq_settings_can_request(desc) ||
+            !irq_settings_is_per_cpu_devid(desc) ||
+            irq_settings_can_autoenable(desc) ||
+            !irq_supports_nmi(desc))
+                return -EINVAL;
+
+        /* The line cannot already be NMI */
+        if (desc->istate & IRQS_NMI)
+                return -EINVAL;
+
+        action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+        if (!action)
+                return -ENOMEM;
+
+        action->handler = handler;
+        action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND | IRQF_NO_THREAD
+                | IRQF_NOBALANCING;
+        action->name = name;
+        action->percpu_dev_id = dev_id;
+
+        retval = irq_chip_pm_get(&desc->irq_data);
+        if (retval < 0)
+                goto err_out;
+
+        retval = __setup_irq(irq, desc, action);
+        if (retval)
+                goto err_irq_setup;
+
+        raw_spin_lock_irqsave(&desc->lock, flags);
+        desc->istate |= IRQS_NMI;
+        raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+        return 0;
+
+err_irq_setup:
+        irq_chip_pm_put(&desc->irq_data);
+err_out:
+        kfree(action);
+
+        return retval;
+}
+
+/**
+ *      prepare_percpu_nmi - performs CPU local setup for NMI delivery
+ *      @irq: Interrupt line to prepare for NMI delivery
+ *
+ *      This call prepares an interrupt line to deliver NMI on the current CPU,
+ *      before that interrupt line gets enabled with enable_percpu_nmi().
+ *
+ *      As a CPU local operation, this should be called from non-preemptible
+ *      context.
+ *
+ *      If the interrupt line cannot be used to deliver NMIs, function
+ *      will fail returning a negative value.
+ */
+int prepare_percpu_nmi(unsigned int irq)
+{
+        unsigned long flags;
+        struct irq_desc *desc;
+        int ret = 0;
+
+        WARN_ON(preemptible());
+
+        desc = irq_get_desc_lock(irq, &flags,
+                                 IRQ_GET_DESC_CHECK_PERCPU);
+        if (!desc)
+                return -EINVAL;
+
+        if (WARN(!(desc->istate & IRQS_NMI),
+                 KERN_ERR "prepare_percpu_nmi called for a non-NMI interrupt: irq %u\n",
+                 irq)) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        ret = irq_nmi_setup(desc);
+        if (ret) {
+                pr_err("Failed to setup NMI delivery: irq %u\n", irq);
+                goto out;
+        }
+
+out:
+        irq_put_desc_unlock(desc, flags);
+        return ret;
+}
+
+/**
+ *      teardown_percpu_nmi - undoes NMI setup of IRQ line
+ *      @irq: Interrupt line from which CPU local NMI configuration should be
+ *            removed
+ *
+ *      This call undoes the setup done by prepare_percpu_nmi().
+ *
+ *      IRQ line should not be enabled for the current CPU.
+ *
+ *      As a CPU local operation, this should be called from non-preemptible
+ *      context.
+ */
+void teardown_percpu_nmi(unsigned int irq)
+{
+        unsigned long flags;
+        struct irq_desc *desc;
+
+        WARN_ON(preemptible());
+
+        desc = irq_get_desc_lock(irq, &flags,
+                                 IRQ_GET_DESC_CHECK_PERCPU);
+        if (!desc)
+                return;
+
+        if (WARN_ON(!(desc->istate & IRQS_NMI)))
+                goto out;
+
+        irq_nmi_teardown(desc);
+out:
+        irq_put_desc_unlock(desc, flags);
+}
+
+/**
  *      irq_get_irqchip_state - returns the irqchip state of a interrupt.
  *      @irq: Interrupt line that is forwarded to a VM
  *      @which: One of IRQCHIP_STATE_* the caller wants to know about