[PATCH V2] mm/thp: Define default pmd_pgtable()

From: Anshuman Khandual
Date: Wed Jun 09 2021 - 00:59:57 EST


Currently most platforms define pmd_pgtable() as pmd_page() duplicating the
same code all over. Instead just define a default value i.e pmd_page() for
pmd_pgtable() and let platforms override when required via <asm/pgtable.h>.
All the existing platform that override pmd_pgtable() have been moved into
their respective <asm/pgtable.h> header in order to precede before the new
generic definition. This makes it much cleaner with reduced code.

Cc: Nick Hu <nickhu@xxxxxxxxxxxxx>
Cc: Richard Henderson <rth@xxxxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Guo Ren <guoren@xxxxxxxxxx>
Cc: Brian Cain <bcain@xxxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Michal Simek <monstr@xxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Ley Foon Tan <ley.foon.tan@xxxxxxxxx>
Cc: Jonas Bonn <jonas@xxxxxxxxxxxx>
Cc: Stefan Kristiansson <stefan.kristiansson@xxxxxxxxxxxxx>
Cc: Stafford Horne <shorne@xxxxxxxxx>
Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Jeff Dike <jdike@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
This patch applies on linux-next (20210608) as there is a merge conflict
dependency on the following commit.

40762590e8be ("mm: define default value for FIRST_USER_ADDRESS").

This patch has been built tested across multiple platforms.

Changes in V2:

- Changed m68k per Geert

Changes in V1:

https://lore.kernel.org/linux-arch/1623130327-13325-1-git-send-email-anshuman.khandual@xxxxxxx/

arch/alpha/include/asm/pgalloc.h | 1 -
arch/arc/include/asm/pgalloc.h | 2 --
arch/arc/include/asm/pgtable.h | 2 ++
arch/arm/include/asm/pgalloc.h | 1 -
arch/arm64/include/asm/pgalloc.h | 1 -
arch/csky/include/asm/pgalloc.h | 2 --
arch/hexagon/include/asm/pgtable.h | 1 -
arch/ia64/include/asm/pgalloc.h | 1 -
arch/m68k/include/asm/mcf_pgalloc.h | 2 --
arch/m68k/include/asm/mcf_pgtable.h | 2 ++
arch/m68k/include/asm/motorola_pgalloc.h | 1 -
arch/m68k/include/asm/motorola_pgtable.h | 2 ++
arch/m68k/include/asm/sun3_pgalloc.h | 1 -
arch/m68k/include/asm/sun3_pgtable.h | 2 ++
arch/microblaze/include/asm/pgalloc.h | 2 --
arch/mips/include/asm/pgalloc.h | 1 -
arch/nds32/include/asm/pgalloc.h | 5 -----
arch/nios2/include/asm/pgalloc.h | 1 -
arch/openrisc/include/asm/pgalloc.h | 2 --
arch/parisc/include/asm/pgalloc.h | 1 -
arch/powerpc/include/asm/pgalloc.h | 5 -----
arch/powerpc/include/asm/pgtable.h | 6 ++++++
arch/riscv/include/asm/pgalloc.h | 2 --
arch/s390/include/asm/pgalloc.h | 3 ---
arch/s390/include/asm/pgtable.h | 3 +++
arch/sh/include/asm/pgalloc.h | 1 -
arch/sparc/include/asm/pgalloc_32.h | 1 -
arch/sparc/include/asm/pgalloc_64.h | 1 -
arch/sparc/include/asm/pgtable_32.h | 2 ++
arch/sparc/include/asm/pgtable_64.h | 2 ++
arch/um/include/asm/pgalloc.h | 1 -
arch/x86/include/asm/pgalloc.h | 2 --
arch/xtensa/include/asm/pgalloc.h | 2 --
include/linux/pgtable.h | 9 +++++++++
34 files changed, 30 insertions(+), 43 deletions(-)

diff --git a/arch/alpha/include/asm/pgalloc.h b/arch/alpha/include/asm/pgalloc.h
index 9c6a24fe493d..68be7adbfe58 100644
--- a/arch/alpha/include/asm/pgalloc.h
+++ b/arch/alpha/include/asm/pgalloc.h
@@ -18,7 +18,6 @@ pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t pte)
{
pmd_set(pmd, (pte_t *)(page_to_pa(pte) + PAGE_OFFSET));
}
-#define pmd_pgtable(pmd) pmd_page(pmd)

static inline void
pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)
diff --git a/arch/arc/include/asm/pgalloc.h b/arch/arc/include/asm/pgalloc.h
index 6147db925248..a32ca3104ced 100644
--- a/arch/arc/include/asm/pgalloc.h
+++ b/arch/arc/include/asm/pgalloc.h
@@ -129,6 +129,4 @@ static inline void pte_free(struct mm_struct *mm, pgtable_t ptep)

#define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, pte)

-#define pmd_pgtable(pmd) ((pgtable_t) pmd_page_vaddr(pmd))
-
#endif /* _ASM_ARC_PGALLOC_H */
diff --git a/arch/arc/include/asm/pgtable.h b/arch/arc/include/asm/pgtable.h
index 577682e8cc7f..320cc0ae8a08 100644
--- a/arch/arc/include/asm/pgtable.h
+++ b/arch/arc/include/asm/pgtable.h
@@ -350,6 +350,8 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,

#define kern_addr_valid(addr) (1)

+#define pmd_pgtable(pmd) ((pgtable_t) pmd_page_vaddr(pmd))
+
/*
* remap a physical page `pfn' of size `size' with page protection `prot'
* into virtual address `from'
diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h
index fdee1f04f4f3..a17f01235c29 100644
--- a/arch/arm/include/asm/pgalloc.h
+++ b/arch/arm/include/asm/pgalloc.h
@@ -143,7 +143,6 @@ pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep)

__pmd_populate(pmdp, page_to_phys(ptep), prot);
}
-#define pmd_pgtable(pmd) pmd_page(pmd)

#endif /* CONFIG_MMU */

diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h
index 31fbab3d6f99..8433a2058eb1 100644
--- a/arch/arm64/include/asm/pgalloc.h
+++ b/arch/arm64/include/asm/pgalloc.h
@@ -86,6 +86,5 @@ pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep)
VM_BUG_ON(mm == &init_mm);
__pmd_populate(pmdp, page_to_phys(ptep), PMD_TYPE_TABLE | PMD_TABLE_PXN);
}
-#define pmd_pgtable(pmd) pmd_page(pmd)

#endif
diff --git a/arch/csky/include/asm/pgalloc.h b/arch/csky/include/asm/pgalloc.h
index cd211aabbefd..bbbd0698b397 100644
--- a/arch/csky/include/asm/pgalloc.h
+++ b/arch/csky/include/asm/pgalloc.h
@@ -22,8 +22,6 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
set_pmd(pmd, __pmd(__pa(page_address(pte))));
}

-#define pmd_pgtable(pmd) pmd_page(pmd)
-
extern void pgd_init(unsigned long *p);

static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm)
diff --git a/arch/hexagon/include/asm/pgtable.h b/arch/hexagon/include/asm/pgtable.h
index e4979508cddf..18cd6ea9ab23 100644
--- a/arch/hexagon/include/asm/pgtable.h
+++ b/arch/hexagon/include/asm/pgtable.h
@@ -239,7 +239,6 @@ static inline int pmd_bad(pmd_t pmd)
* pmd_page - converts a PMD entry to a page pointer
*/
#define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
-#define pmd_pgtable(pmd) pmd_page(pmd)

/**
* pte_none - check if pte is mapped
diff --git a/arch/ia64/include/asm/pgalloc.h b/arch/ia64/include/asm/pgalloc.h
index 9601cfe83c94..0fb2b6291d58 100644
--- a/arch/ia64/include/asm/pgalloc.h
+++ b/arch/ia64/include/asm/pgalloc.h
@@ -52,7 +52,6 @@ pmd_populate(struct mm_struct *mm, pmd_t * pmd_entry, pgtable_t pte)
{
pmd_val(*pmd_entry) = page_to_phys(pte);
}
-#define pmd_pgtable(pmd) pmd_page(pmd)

static inline void
pmd_populate_kernel(struct mm_struct *mm, pmd_t * pmd_entry, pte_t * pte)
diff --git a/arch/m68k/include/asm/mcf_pgalloc.h b/arch/m68k/include/asm/mcf_pgalloc.h
index bc1228e00518..5c2c0a864524 100644
--- a/arch/m68k/include/asm/mcf_pgalloc.h
+++ b/arch/m68k/include/asm/mcf_pgalloc.h
@@ -32,8 +32,6 @@ extern inline pmd_t *pmd_alloc_kernel(pgd_t *pgd, unsigned long address)

#define pmd_populate_kernel pmd_populate

-#define pmd_pgtable(pmd) pfn_to_virt(pmd_val(pmd) >> PAGE_SHIFT)
-
static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pgtable,
unsigned long address)
{
diff --git a/arch/m68k/include/asm/mcf_pgtable.h b/arch/m68k/include/asm/mcf_pgtable.h
index 8d4ec05996c5..6f2b87d7a50d 100644
--- a/arch/m68k/include/asm/mcf_pgtable.h
+++ b/arch/m68k/include/asm/mcf_pgtable.h
@@ -150,6 +150,8 @@

#ifndef __ASSEMBLY__

+#define pmd_pgtable(pmd) pfn_to_virt(pmd_val(pmd) >> PAGE_SHIFT)
+
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
diff --git a/arch/m68k/include/asm/motorola_pgalloc.h b/arch/m68k/include/asm/motorola_pgalloc.h
index b4fc3b4f6bb3..74a817d9387f 100644
--- a/arch/m68k/include/asm/motorola_pgalloc.h
+++ b/arch/m68k/include/asm/motorola_pgalloc.h
@@ -88,7 +88,6 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t page
{
pmd_set(pmd, page);
}
-#define pmd_pgtable(pmd) ((pgtable_t)pmd_page_vaddr(pmd))

static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
{
diff --git a/arch/m68k/include/asm/motorola_pgtable.h b/arch/m68k/include/asm/motorola_pgtable.h
index 8076467eff4b..a2908164ee6f 100644
--- a/arch/m68k/include/asm/motorola_pgtable.h
+++ b/arch/m68k/include/asm/motorola_pgtable.h
@@ -105,6 +105,8 @@ extern unsigned long mm_cachebits;
#define __S110 PAGE_SHARED_C
#define __S111 PAGE_SHARED_C

+#define pmd_pgtable(pmd) ((pgtable_t)pmd_page_vaddr(pmd))
+
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
diff --git a/arch/m68k/include/asm/sun3_pgalloc.h b/arch/m68k/include/asm/sun3_pgalloc.h
index 000f64869b91..198036aff519 100644
--- a/arch/m68k/include/asm/sun3_pgalloc.h
+++ b/arch/m68k/include/asm/sun3_pgalloc.h
@@ -32,7 +32,6 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd, pgtable_t page
{
pmd_val(*pmd) = __pa((unsigned long)page_address(page));
}
-#define pmd_pgtable(pmd) pmd_page(pmd)

/*
* allocating and freeing a pmd is trivial: the 1-entry pmd is
diff --git a/arch/m68k/include/asm/sun3_pgtable.h b/arch/m68k/include/asm/sun3_pgtable.h
index 5b24283a0a42..127282bd8b96 100644
--- a/arch/m68k/include/asm/sun3_pgtable.h
+++ b/arch/m68k/include/asm/sun3_pgtable.h
@@ -96,6 +96,8 @@

#ifndef __ASSEMBLY__

+#define pmd_pgtable(pmd) pmd_page(pmd)
+
/*
* Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to.
diff --git a/arch/microblaze/include/asm/pgalloc.h b/arch/microblaze/include/asm/pgalloc.h
index d56b9f670ad1..6c33b05f730f 100644
--- a/arch/microblaze/include/asm/pgalloc.h
+++ b/arch/microblaze/include/asm/pgalloc.h
@@ -28,8 +28,6 @@ static inline pgd_t *get_pgd(void)

#define pgd_alloc(mm) get_pgd()

-#define pmd_pgtable(pmd) pmd_page(pmd)
-
extern pte_t *pte_alloc_one_kernel(struct mm_struct *mm);

#define __pte_free_tlb(tlb, pte, addr) pte_free((tlb)->mm, (pte))
diff --git a/arch/mips/include/asm/pgalloc.h b/arch/mips/include/asm/pgalloc.h
index 8b18424b3120..dd53d0f79cb3 100644
--- a/arch/mips/include/asm/pgalloc.h
+++ b/arch/mips/include/asm/pgalloc.h
@@ -28,7 +28,6 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
{
set_pmd(pmd, __pmd((unsigned long)page_address(pte)));
}
-#define pmd_pgtable(pmd) pmd_page(pmd)

/*
* Initialize a new pmd table with invalid pointers.
diff --git a/arch/nds32/include/asm/pgalloc.h b/arch/nds32/include/asm/pgalloc.h
index 85c117347c86..a08e1ebca70e 100644
--- a/arch/nds32/include/asm/pgalloc.h
+++ b/arch/nds32/include/asm/pgalloc.h
@@ -12,11 +12,6 @@
#define __HAVE_ARCH_PTE_ALLOC_ONE
#include <asm-generic/pgalloc.h> /* for pte_{alloc,free}_one */

-/*
- * Since we have only two-level page tables, these are trivial
- */
-#define pmd_pgtable(pmd) pmd_page(pmd)
-
extern pgd_t *pgd_alloc(struct mm_struct *mm);
extern void pgd_free(struct mm_struct *mm, pgd_t * pgd);

diff --git a/arch/nios2/include/asm/pgalloc.h b/arch/nios2/include/asm/pgalloc.h
index e6600d2a5ae0..3c4ae74d5798 100644
--- a/arch/nios2/include/asm/pgalloc.h
+++ b/arch/nios2/include/asm/pgalloc.h
@@ -25,7 +25,6 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
{
set_pmd(pmd, __pmd((unsigned long)page_address(pte)));
}
-#define pmd_pgtable(pmd) pmd_page(pmd)

/*
* Initialize a new pmd table with invalid pointers.
diff --git a/arch/openrisc/include/asm/pgalloc.h b/arch/openrisc/include/asm/pgalloc.h
index 88820299ecc4..b7b2b8d16fad 100644
--- a/arch/openrisc/include/asm/pgalloc.h
+++ b/arch/openrisc/include/asm/pgalloc.h
@@ -72,6 +72,4 @@ do { \
tlb_remove_page((tlb), (pte)); \
} while (0)

-#define pmd_pgtable(pmd) pmd_page(pmd)
-
#endif
diff --git a/arch/parisc/include/asm/pgalloc.h b/arch/parisc/include/asm/pgalloc.h
index dda557085311..6a7e98e71f1d 100644
--- a/arch/parisc/include/asm/pgalloc.h
+++ b/arch/parisc/include/asm/pgalloc.h
@@ -69,6 +69,5 @@ pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd, pte_t *pte)

#define pmd_populate(mm, pmd, pte_page) \
pmd_populate_kernel(mm, pmd, page_address(pte_page))
-#define pmd_pgtable(pmd) pmd_page(pmd)

#endif
diff --git a/arch/powerpc/include/asm/pgalloc.h b/arch/powerpc/include/asm/pgalloc.h
index 6dd78a2dc03a..3360cad78ace 100644
--- a/arch/powerpc/include/asm/pgalloc.h
+++ b/arch/powerpc/include/asm/pgalloc.h
@@ -70,9 +70,4 @@ extern struct kmem_cache *pgtable_cache[];
#include <asm/nohash/pgalloc.h>
#endif

-static inline pgtable_t pmd_pgtable(pmd_t pmd)
-{
- return (pgtable_t)pmd_page_vaddr(pmd);
-}
-
#endif /* _ASM_POWERPC_PGALLOC_H */
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index c6a676714f04..5969743719bc 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -152,6 +152,12 @@ static inline bool p4d_is_leaf(p4d_t p4d)
}
#endif

+#define pmd_pgtable pmd_pgtable
+static inline pgtable_t pmd_pgtable(pmd_t pmd)
+{
+ return (pgtable_t)pmd_page_vaddr(pmd);
+}
+
#ifdef CONFIG_PPC64
#define is_ioremap_addr is_ioremap_addr
static inline bool is_ioremap_addr(const void *x)
diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
index 23b1544e0ca5..0af6933a7100 100644
--- a/arch/riscv/include/asm/pgalloc.h
+++ b/arch/riscv/include/asm/pgalloc.h
@@ -38,8 +38,6 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd)
}
#endif /* __PAGETABLE_PMD_FOLDED */

-#define pmd_pgtable(pmd) pmd_page(pmd)
-
static inline pgd_t *pgd_alloc(struct mm_struct *mm)
{
pgd_t *pgd;
diff --git a/arch/s390/include/asm/pgalloc.h b/arch/s390/include/asm/pgalloc.h
index 6b187cd72251..f14a555eff74 100644
--- a/arch/s390/include/asm/pgalloc.h
+++ b/arch/s390/include/asm/pgalloc.h
@@ -134,9 +134,6 @@ static inline void pmd_populate(struct mm_struct *mm,

#define pmd_populate_kernel(mm, pmd, pte) pmd_populate(mm, pmd, pte)

-#define pmd_pgtable(pmd) \
- ((pgtable_t)__va(pmd_val(pmd) & -sizeof(pte_t)*PTRS_PER_PTE))
-
/*
* page table entry allocation/free routines.
*/
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h
index 7c66ae5d7e32..b9760abe0c98 100644
--- a/arch/s390/include/asm/pgtable.h
+++ b/arch/s390/include/asm/pgtable.h
@@ -1730,4 +1730,7 @@ extern void s390_reset_cmma(struct mm_struct *mm);
#define HAVE_ARCH_UNMAPPED_AREA
#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN

+#define pmd_pgtable(pmd) \
+ ((pgtable_t)__va(pmd_val(pmd) & -sizeof(pte_t)*PTRS_PER_PTE))
+
#endif /* _S390_PAGE_H */
diff --git a/arch/sh/include/asm/pgalloc.h b/arch/sh/include/asm/pgalloc.h
index 0e6b0be25e33..a9e98233c4d4 100644
--- a/arch/sh/include/asm/pgalloc.h
+++ b/arch/sh/include/asm/pgalloc.h
@@ -30,7 +30,6 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
{
set_pmd(pmd, __pmd((unsigned long)page_address(pte)));
}
-#define pmd_pgtable(pmd) pmd_page(pmd)

#define __pte_free_tlb(tlb,pte,addr) \
do { \
diff --git a/arch/sparc/include/asm/pgalloc_32.h b/arch/sparc/include/asm/pgalloc_32.h
index 9d353e6dc5a9..4f73e87b22a3 100644
--- a/arch/sparc/include/asm/pgalloc_32.h
+++ b/arch/sparc/include/asm/pgalloc_32.h
@@ -51,7 +51,6 @@ static inline void free_pmd_fast(pmd_t * pmd)
#define __pmd_free_tlb(tlb, pmd, addr) pmd_free((tlb)->mm, pmd)

#define pmd_populate(mm, pmd, pte) pmd_set(pmd, pte)
-#define pmd_pgtable(pmd) (pgtable_t)__pmd_page(pmd)

void pmd_set(pmd_t *pmdp, pte_t *ptep);
#define pmd_populate_kernel pmd_populate
diff --git a/arch/sparc/include/asm/pgalloc_64.h b/arch/sparc/include/asm/pgalloc_64.h
index a8dafc550985..7b5561d17ab1 100644
--- a/arch/sparc/include/asm/pgalloc_64.h
+++ b/arch/sparc/include/asm/pgalloc_64.h
@@ -67,7 +67,6 @@ void pte_free(struct mm_struct *mm, pgtable_t ptepage);

#define pmd_populate_kernel(MM, PMD, PTE) pmd_set(MM, PMD, PTE)
#define pmd_populate(MM, PMD, PTE) pmd_set(MM, PMD, PTE)
-#define pmd_pgtable(PMD) ((pte_t *)pmd_page_vaddr(PMD))

void pgtable_free(void *table, bool is_page);

diff --git a/arch/sparc/include/asm/pgtable_32.h b/arch/sparc/include/asm/pgtable_32.h
index 0888bda245f5..ebaf374b55ab 100644
--- a/arch/sparc/include/asm/pgtable_32.h
+++ b/arch/sparc/include/asm/pgtable_32.h
@@ -432,4 +432,6 @@ static inline int io_remap_pfn_range(struct vm_area_struct *vma,
/* We provide our own get_unmapped_area to cope with VA holes for userland */
#define HAVE_ARCH_UNMAPPED_AREA

+#define pmd_pgtable(pmd) ((pgtable_t)__pmd_page(pmd))
+
#endif /* !(_SPARC_PGTABLE_H) */
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index a400e0f23046..e0ee48ec3903 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -1117,6 +1117,8 @@ extern unsigned long cmdline_memory_size;

asmlinkage void do_sparc64_fault(struct pt_regs *regs);

+#define pmd_pgtable(PMD) ((pte_t *)pmd_page_vaddr(PMD))
+
#ifdef CONFIG_HUGETLB_PAGE

#define pud_leaf_size pud_leaf_size
diff --git a/arch/um/include/asm/pgalloc.h b/arch/um/include/asm/pgalloc.h
index 2bbf28cf3aa9..8ec7cd46dd96 100644
--- a/arch/um/include/asm/pgalloc.h
+++ b/arch/um/include/asm/pgalloc.h
@@ -19,7 +19,6 @@
set_pmd(pmd, __pmd(_PAGE_TABLE + \
((unsigned long long)page_to_pfn(pte) << \
(unsigned long long) PAGE_SHIFT)))
-#define pmd_pgtable(pmd) pmd_page(pmd)

/*
* Allocate and free page tables.
diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h
index 62ad61d6fefc..c7ec5bb88334 100644
--- a/arch/x86/include/asm/pgalloc.h
+++ b/arch/x86/include/asm/pgalloc.h
@@ -84,8 +84,6 @@ static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
set_pmd(pmd, __pmd(((pteval_t)pfn << PAGE_SHIFT) | _PAGE_TABLE));
}

-#define pmd_pgtable(pmd) pmd_page(pmd)
-
#if CONFIG_PGTABLE_LEVELS > 2
extern void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd);

diff --git a/arch/xtensa/include/asm/pgalloc.h b/arch/xtensa/include/asm/pgalloc.h
index d3a22da4d2c9..eeb2de3a89e5 100644
--- a/arch/xtensa/include/asm/pgalloc.h
+++ b/arch/xtensa/include/asm/pgalloc.h
@@ -25,7 +25,6 @@
(pmd_val(*(pmdp)) = ((unsigned long)ptep))
#define pmd_populate(mm, pmdp, page) \
(pmd_val(*(pmdp)) = ((unsigned long)page_to_virt(page)))
-#define pmd_pgtable(pmd) pmd_page(pmd)

static inline pgd_t*
pgd_alloc(struct mm_struct *mm)
@@ -63,7 +62,6 @@ static inline pgtable_t pte_alloc_one(struct mm_struct *mm)
return page;
}

-#define pmd_pgtable(pmd) pmd_page(pmd)
#endif /* CONFIG_MMU */

#endif /* _XTENSA_PGALLOC_H */
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 9e6f71265f72..5fa6d69759ef 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -37,6 +37,15 @@
#define FIRST_USER_ADDRESS 0UL
#endif

+/*
+ * This defines the generic helper for accessing PMD page
+ * table page. Although platforms can still override this
+ * via their respective <asm/pgtable.h>.
+ */
+#ifndef pmd_pgtable
+#define pmd_pgtable(pmd) pmd_page(pmd)
+#endif
+
/*
* A page table page can be thought of an array like this: pXd_t[PTRS_PER_PxD]
*
--
2.20.1