diff --git a/arch/x86/include/asm/vsyscall.h b/arch/x86/include/asm/vsyscall.h
index 6ba66ee..4865e10 100644
--- a/arch/x86/include/asm/vsyscall.h
+++ b/arch/x86/include/asm/vsyscall.h
@@ -12,12 +12,14 @@
  * Returns true if handled.
  */
 extern bool emulate_vsyscall(struct pt_regs *regs, unsigned long address);
+extern bool vsyscall_enabled(void);
 #else
 static inline void map_vsyscall(void) {}
 static inline bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
 {
 	return false;
 }
+static inline bool vsyscall_enabled(void) { return false; }
 #endif
 
 #endif /* _ASM_X86_VSYSCALL_H */