Merge tag 'pci-v5.7-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

[linux-2.6-microblaze.git] / kernel / irq / resend.c

diff --git a/kernel/irq/resend.c b/kernel/irq/resend.c
index a21fc4e..27634f4 100644 (file)
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -91,8 +91,10 @@ static int irq_sw_resend(struct irq_desc *desc)
  *
  * Is called with interrupts disabled and desc->lock held.
  */
-int check_irq_resend(struct irq_desc *desc)
+int check_irq_resend(struct irq_desc *desc, bool inject)
 {
+       int err = 0;
+
        /*
         * We do not resend level type interrupts. Level type interrupts
         * are resent by hardware when they are still active. Clear the
@@ -106,13 +108,66 @@ int check_irq_resend(struct irq_desc *desc)
        if (desc->istate & IRQS_REPLAY)
                return -EBUSY;
 
-       if (desc->istate & IRQS_PENDING) {
-               desc->istate &= ~IRQS_PENDING;
+       if (!(desc->istate & IRQS_PENDING) && !inject)
+               return 0;
+
+       desc->istate &= ~IRQS_PENDING;
+
+       if (!desc->irq_data.chip->irq_retrigger ||
+           !desc->irq_data.chip->irq_retrigger(&desc->irq_data))
+               err = irq_sw_resend(desc);
+
+       /* If the retrigger was successfull, mark it with the REPLAY bit */
+       if (!err)
                desc->istate |= IRQS_REPLAY;
+       return err;
+}
 
-               if (!desc->irq_data.chip->irq_retrigger ||
-                   !desc->irq_data.chip->irq_retrigger(&desc->irq_data))
-                   return irq_sw_resend(desc);
-       }
-       return 0;
+#ifdef CONFIG_GENERIC_IRQ_INJECTION
+/**
+ * irq_inject_interrupt - Inject an interrupt for testing/error injection
+ * @irq:       The interrupt number
+ *
+ * This function must only be used for debug and testing purposes!
+ *
+ * Especially on x86 this can cause a premature completion of an interrupt
+ * affinity change causing the interrupt line to become stale. Very
+ * unlikely, but possible.
+ *
+ * The injection can fail for various reasons:
+ * - Interrupt is not activated
+ * - Interrupt is NMI type or currently replaying
+ * - Interrupt is level type
+ * - Interrupt does not support hardware retrigger and software resend is
+ *   either not enabled or not possible for the interrupt.
+ */
+int irq_inject_interrupt(unsigned int irq)
+{
+       struct irq_desc *desc;
+       unsigned long flags;
+       int err;
+
+       /* Try the state injection hardware interface first */
+       if (!irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true))
+               return 0;
+
+       /* That failed, try via the resend mechanism */
+       desc = irq_get_desc_buslock(irq, &flags, 0);
+       if (!desc)
+               return -EINVAL;
+
+       /*
+        * Only try to inject when the interrupt is:
+        *  - not NMI type
+        *  - activated
+        */
+       if ((desc->istate & IRQS_NMI) || !irqd_is_activated(&desc->irq_data))
+               err = -EINVAL;
+       else
+               err = check_irq_resend(desc, true);
+
+       irq_put_desc_busunlock(desc, flags);
+       return err;
 }
+EXPORT_SYMBOL_GPL(irq_inject_interrupt);
+#endif