diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 9f8ea0e33eb1..661b2b4fe758 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -648,6 +648,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
 
 #define __pud_to_phys(pud)  (__page_val_to_pfn(pud_val(pud)) << PAGE_SHIFT)
 
+#define pud_pfn pud_pfn
 static inline unsigned long pud_pfn(pud_t pud)
 {
 	return ((__pud_to_phys(pud) & PUD_MASK) >> PAGE_SHIFT);
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 60950e7a25f5..2cb2a2e7b34b 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1405,6 +1405,7 @@ static inline unsigned long pud_deref(pud_t pud)
 	return (unsigned long)__va(pud_val(pud) & origin_mask);
 }
 
+#define pud_pfn pud_pfn
 static inline unsigned long pud_pfn(pud_t pud)
 {
 	return __pa(pud_deref(pud)) >> PAGE_SHIFT;
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 4d1bafaba942..26efc9bb644a 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -875,6 +875,7 @@ static inline bool pud_leaf(pud_t pud)
 	return pte_val(pte) & _PAGE_PMD_HUGE;
 }
 
+#define pud_pfn pud_pfn
 static inline unsigned long pud_pfn(pud_t pud)
 {
 	pte_t pte = __pte(pud_val(pud));
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index cefc7a84f7a4..273f7557218c 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -234,6 +234,7 @@ static inline unsigned long pmd_pfn(pmd_t pmd)
 	return (pfn & pmd_pfn_mask(pmd)) >> PAGE_SHIFT;
 }
 
+#define pud_pfn pud_pfn
 static inline unsigned long pud_pfn(pud_t pud)
 {
 	phys_addr_t pfn = pud_val(pud);
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 09c85c7bf9c2..f108c7a3c1d9 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1819,6 +1819,20 @@ typedef unsigned int pgtbl_mod_mask;
 #define pte_leaf_size(x) PAGE_SIZE
 #endif
 
+/*
+ * We always define pmd_pfn for all archs as it's used in lots of generic
+ * code.  Now it happens too for pud_pfn (and can happen for larger
+ * mappings too in the future; we're not there yet).  Instead of defining
+ * it for all archs (like pmd_pfn), provide a fallback.
+ *
+ * Note that returning 0 here means any arch that didn't define this can
+ * get severely wrong when it hits a real pud leaf.  It's arch's
+ * responsibility to properly define it when a huge pud is possible.
+ */
+#ifndef pud_pfn
+#define pud_pfn(x) 0
+#endif
+
 /*
  * Some architectures have MMUs that are configurable or selectable at boot
  * time. These lead to variable PTRS_PER_x. For statically allocated arrays it