diff --git a/arch/x86/kernel/cpu/cpu.h b/arch/x86/kernel/cpu/cpu.h
index 5c7a3a71191a..dca2d5845e42 100644
--- a/arch/x86/kernel/cpu/cpu.h
+++ b/arch/x86/kernel/cpu/cpu.h
@@ -75,7 +75,6 @@ static inline struct amd_northbridge *amd_init_l3_cache(int index)
 }
 #endif
 
-unsigned int aperfmperf_get_khz(int cpu);
 void cpu_select_mitigations(void);
 
 extern void x86_spec_ctrl_setup_ap(void);