[IA64] pvops: paravirtualize NR_IRQS

Make NR_IRQ overridable by each pv instances.
Pv instance may need each own number of irqs so that
NR_IRQS should be the maximum number of nr_irqs each
pv instances need.

Cc: Jes Sorensen <jes@sgi.com>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/kernel/nr-irqs.c

@@ -0,0 +1,24 @@
+/*
+ * calculate
+ * NR_IRQS = max(IA64_NATIVE_NR_IRQS, XEN_NR_IRQS, FOO_NR_IRQS...)
+ * depending on config.
+ * This must be calculated before processing asm-offset.c.
+ */
+
+#define ASM_OFFSETS_C 1
+
+#include <linux/kbuild.h>
+#include <linux/threads.h>
+#include <asm-ia64/native/irq.h>
+
+void foo(void)
+{
+	union paravirt_nr_irqs_max {
+		char ia64_native_nr_irqs[IA64_NATIVE_NR_IRQS];
+#ifdef CONFIG_XEN
+		char xen_nr_irqs[XEN_NR_IRQS];
+#endif
+	};
+
+	DEFINE(NR_IRQS, sizeof (union paravirt_nr_irqs_max));
+}