#define p4d_ERROR(p4d) (pgd_ERROR((p4d).pgd))
#define pgd_populate(mm, pgd, p4d) do { } while (0)
+#define pgd_populate_safe(mm, pgd, p4d) do { } while (0)
/*
* (p4ds are folded into pgds so this doesn't get actually called,
* but the define is needed for a generic inline function.)