diff --git a/target-microblaze/mmu.h b/target-microblaze/mmu.h
index 3f74dda0b0c8..3b7a9983d57e 100644
--- a/target-microblaze/mmu.h
+++ b/target-microblaze/mmu.h
@@ -82,7 +82,6 @@ struct microblaze_mmu_lookup
     } err;
 };
 
-void mmu_flip_um(CPUMBState *env, unsigned int um);
 unsigned int mmu_translate(struct microblaze_mmu *mmu,
                            struct microblaze_mmu_lookup *lu,
                            target_ulong vaddr, int rw, int mmu_idx);