8 files changed, 30 insertions, 6 deletions
diff --git a/include/asm-generic/4level-fixup.h b/include/asm-generic/4level-fixup.h
index 89f3b03b1445..e3667c9a33a5 100644
--- a/include/asm-generic/4level-fixup.h
+++ b/include/asm-generic/4level-fixup.h
@@ -3,7 +3,7 @@
 #define _4LEVEL_FIXUP_H
 
 #define __ARCH_HAS_4LEVEL_HACK
-#define __PAGETABLE_PUD_FOLDED
+#define __PAGETABLE_PUD_FOLDED 1
 
 #define PUD_SHIFT			PGDIR_SHIFT
 #define PUD_SIZE			PGDIR_SIZE
diff --git a/include/asm-generic/5level-fixup.h b/include/asm-generic/5level-fixup.h
index 9c2e0708eb82..73474bb52344 100644
--- a/include/asm-generic/5level-fixup.h
+++ b/include/asm-generic/5level-fixup.h
@@ -3,7 +3,7 @@
 #define _5LEVEL_FIXUP_H
 
 #define __ARCH_HAS_5LEVEL_HACK
-#define __PAGETABLE_P4D_FOLDED
+#define __PAGETABLE_P4D_FOLDED 1
 
 #define P4D_SHIFT			PGDIR_SHIFT
 #define P4D_SIZE			PGDIR_SIZE
diff --git a/include/asm-generic/pgtable-nop4d-hack.h b/include/asm-generic/pgtable-nop4d-hack.h
index 0c34215263b8..1d6dd38c0e5e 100644
--- a/include/asm-generic/pgtable-nop4d-hack.h
+++ b/include/asm-generic/pgtable-nop4d-hack.h
@@ -5,7 +5,7 @@
 #ifndef __ASSEMBLY__
 #include <asm-generic/5level-fixup.h>
 
-#define __PAGETABLE_PUD_FOLDED
+#define __PAGETABLE_PUD_FOLDED 1
 
 /*
  * Having the pud type consist of a pgd gets the size right, and allows
diff --git a/include/asm-generic/pgtable-nop4d.h b/include/asm-generic/pgtable-nop4d.h
index 1a29b2a0282b..04cb913797bc 100644
--- a/include/asm-generic/pgtable-nop4d.h
+++ b/include/asm-generic/pgtable-nop4d.h
@@ -4,7 +4,7 @@
 
 #ifndef __ASSEMBLY__
 
-#define __PAGETABLE_P4D_FOLDED
+#define __PAGETABLE_P4D_FOLDED 1
 
 typedef struct { pgd_t pgd; } p4d_t;
 
diff --git a/include/asm-generic/pgtable-nopmd.h b/include/asm-generic/pgtable-nopmd.h
index f35f6e8149e4..b85b8271a73d 100644
--- a/include/asm-generic/pgtable-nopmd.h
+++ b/include/asm-generic/pgtable-nopmd.h
@@ -8,7 +8,7 @@
 
 struct mm_struct;
 
-#define __PAGETABLE_PMD_FOLDED
+#define __PAGETABLE_PMD_FOLDED 1
 
 /*
  * Having the pmd type consist of a pud gets the size right, and allows
diff --git a/include/asm-generic/pgtable-nopud.h b/include/asm-generic/pgtable-nopud.h
index e950b9c50f34..9bef475db6fe 100644
--- a/include/asm-generic/pgtable-nopud.h
+++ b/include/asm-generic/pgtable-nopud.h
@@ -9,7 +9,7 @@
 #else
 #include <asm-generic/pgtable-nop4d.h>
 
-#define __PAGETABLE_PUD_FOLDED
+#define __PAGETABLE_PUD_FOLDED 1
 
 /*
  * Having the pud type consist of a p4d gets the size right, and allows
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 5657a20e0c59..359fb935ded6 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1127,4 +1127,20 @@ static inline bool arch_has_pfn_modify_check(void)
 #endif
 #endif
 
+/*
+ * On some architectures it depends on the mm if the p4d/pud or pmd
+ * layer of the page table hierarchy is folded or not.
+ */
+#ifndef mm_p4d_folded
+#define mm_p4d_folded(mm)	__is_defined(__PAGETABLE_P4D_FOLDED)
+#endif
+
+#ifndef mm_pud_folded
+#define mm_pud_folded(mm)	__is_defined(__PAGETABLE_PUD_FOLDED)
+#endif
+
+#ifndef mm_pmd_folded
+#define mm_pmd_folded(mm)	__is_defined(__PAGETABLE_PMD_FOLDED)
+#endif
+
 #endif /* _ASM_GENERIC_PGTABLE_H */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fcf9cc9d535f..5411de93a363 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1744,11 +1744,15 @@ int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address);
 
 static inline void mm_inc_nr_puds(struct mm_struct *mm)
 {
+	if (mm_pud_folded(mm))
+		return;
 	atomic_long_add(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes);
 }
 
 static inline void mm_dec_nr_puds(struct mm_struct *mm)
 {
+	if (mm_pud_folded(mm))
+		return;
 	atomic_long_sub(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes);
 }
 #endif
@@ -1768,11 +1772,15 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
 
 static inline void mm_inc_nr_pmds(struct mm_struct *mm)
 {
+	if (mm_pmd_folded(mm))
+		return;
 	atomic_long_add(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes);
 }
 
 static inline void mm_dec_nr_pmds(struct mm_struct *mm)
 {
+	if (mm_pmd_folded(mm))
+		return;
 	atomic_long_sub(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes);
 }
 #endif