diff --git a/arch/x86/include/asm/io_apic.h b/arch/x86/include/asm/io_apic.h
index 4f07bf6..690d1cc 100644
--- a/arch/x86/include/asm/io_apic.h
+++ b/arch/x86/include/asm/io_apic.h
@@ -108,6 +108,7 @@
 
 extern int mpc_ioapic_id(int ioapic);
 extern unsigned int mpc_ioapic_addr(int ioapic);
+extern struct mp_ioapic_gsi *mp_ioapic_gsi_routing(int ioapic);
 
 #define MP_MAX_IOAPIC_PIN 127