irqdesc: Add domain handler for NMIs

NMI handling code should be executed between calls to nmi_enter and
nmi_exit.

Add a separate domain handler to properly setup NMI context when handling
an interrupt requested as NMI.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

2 files changed, 40 insertions, 0 deletions

diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index dd1e40ddac7d..ba05b0d6401a 100644
--- a/include/linux/irqdesc.h
+++ b/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 */
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index ee062b7939d3..a1d7a7d484e0 100644
--- a/kernel/irq/irqdesc.c
+++ b/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 */