File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/arm64/include/asm/xen/events.h b/arch/arm64/include/asm/xen/events.h
new file mode 100644
index 0000000..4318866
--- /dev/null
+++ b/arch/arm64/include/asm/xen/events.h
@@ -0,0 +1,27 @@
+#ifndef _ASM_ARM64_XEN_EVENTS_H
+#define _ASM_ARM64_XEN_EVENTS_H
+
+#include <asm/ptrace.h>
+#include <asm/atomic.h>
+
+enum ipi_vector {
+	XEN_PLACEHOLDER_VECTOR,
+
+	/* Xen IPIs go here */
+	XEN_NR_IPIS,
+};
+
+static inline int xen_irqs_disabled(struct pt_regs *regs)
+{
+	return raw_irqs_disabled_flags((unsigned long) regs->pstate);
+}
+
+#define xchg_xen_ulong(ptr, val) xchg((ptr), (val))
+
+/* Rebind event channel is supported by default */
+static inline bool xen_support_evtchn_rebind(void)
+{
+	return true;
+}
+
+#endif /* _ASM_ARM64_XEN_EVENTS_H */