[PATCH 0/3] arm64: Add support for PUD THP

COOLING6d

6 messages, 2 authors, 6d ago · open the first message on its own page

[PATCH 0/3] arm64: Add support for PUD THP

From: Jinjiang Tu <hidden>
Date: 2026-09-09 09:28:50

This series adds PUD THP support for arm64, enabling PUD THP for DAX
and pfnmap.

Patch 1 moves the identical pudp_invalidate() implementations from x86
and riscv to a generic location so arm64 can reuse it.

Patch 2 is a minor cleanup that simplifies pmd_special/pmd_mkspecial.

Patch 3 adds the necessary PUD page table helpers and selects
HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD.

Jinjiang Tu (3):
  mm: define generic pudp_invalidate() implementation
  arm64: simplify pmd_special and pmd_mkspecial
  arm64: Add support for PUD THP

 arch/arm64/Kconfig                           |  1 +
 arch/arm64/include/asm/pgtable.h             | 71 +++++++++++++++-----
 arch/powerpc/include/asm/book3s/64/pgtable.h |  1 +
 arch/riscv/include/asm/pgtable.h             |  3 -
 arch/riscv/mm/pgtable.c                      |  9 ---
 arch/x86/include/asm/pgtable.h               |  3 -
 arch/x86/mm/pgtable.c                        | 12 ----
 include/linux/pgtable.h                      |  7 ++
 mm/pgtable-generic.c                         | 14 ++++
 9 files changed, 77 insertions(+), 44 deletions(-)

-- 
2.43.0

[PATCH 2/3] arm64: simplify pmd_special and pmd_mkspecial

From: Jinjiang Tu <hidden>
Date: 2026-09-09 09:28:47

Use pte_special() and pte_mkspecial() helper to simplify pmd_special()
and pmd_mkspecial(), and kill unused set_pmd_bit() and clear_pmd_bit()
helper.

Signed-off-by: Jinjiang Tu <redacted>
---
 arch/arm64/include/asm/pgtable.h | 19 ++-----------------
 1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 6000905a2e86..427ea3d2bac7 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h

@@ -243,18 +243,6 @@ static inline pte_t set_pte_bit(pte_t pte, pgprot_t prot)
 	return pte;
 }
 
-static inline pmd_t clear_pmd_bit(pmd_t pmd, pgprot_t prot)
-{
-	pmd_val(pmd) &= ~pgprot_val(prot);
-	return pmd;
-}
-
-static inline pmd_t set_pmd_bit(pmd_t pmd, pgprot_t prot)
-{
-	pmd_val(pmd) |= pgprot_val(prot);
-	return pmd;
-}
-
 static inline pte_t pte_mkwrite_novma(pte_t pte)
 {
 	pte = set_pte_bit(pte, __pgprot(PTE_WRITE));

@@ -619,11 +607,8 @@ static inline pmd_t pmd_mkhuge(pmd_t pmd)
 }
 
 #ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
-#define pmd_special(pte)	(!!((pmd_val(pte) & PTE_SPECIAL)))
-static inline pmd_t pmd_mkspecial(pmd_t pmd)
-{
-	return set_pmd_bit(pmd, __pgprot(PTE_SPECIAL));
-}
+#define pmd_special(pmd)	pte_special(pmd_pte(pmd))
+#define pmd_mkspecial(pmd)	pte_pmd(pte_mkspecial(pmd_pte(pmd)))
 #endif
 
 #define __pmd_to_phys(pmd)	__pte_to_phys(pmd_pte(pmd))

-- 
2.43.0

[PATCH 1/3] mm: define generic pudp_invalidate() implementation

From: Jinjiang Tu <hidden>
Date: 2026-09-09 09:28:54

x86 and riscv have identical pudp_invalidate() implementations. Move it to
mm/pgtable-generic.c with the __HAVE_ARCH_PUDP_INVALIDATE override guard.
PowerPC keeps its own implementation. In the later patch, arm64 will use
the generic implementation too.

No functional change intended.

Signed-off-by: Jinjiang Tu <redacted>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h |  1 +
 arch/riscv/include/asm/pgtable.h             |  3 ---
 arch/riscv/mm/pgtable.c                      |  9 ---------
 arch/x86/include/asm/pgtable.h               |  3 ---
 arch/x86/mm/pgtable.c                        | 12 ------------
 include/linux/pgtable.h                      |  7 +++++++
 mm/pgtable-generic.c                         | 14 ++++++++++++++
 7 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index f4db7d7fbd5c..55d33c5537f1 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -1419,6 +1419,7 @@ static inline pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm,
 #define __HAVE_ARCH_PMDP_INVALIDATE
 extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 			     pmd_t *pmdp);
+#define __HAVE_ARCH_PUDP_INVALIDATE
 extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
 			     pud_t *pudp);

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 40b1ed4f3ea8..327fa378032b 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h

@@ -1159,9 +1159,6 @@ static inline pud_t pud_mkinvalid(pud_t pud)
 	return __pud(pud_val(pud) & ~(_PAGE_PRESENT | _PAGE_PROT_NONE));
 }
 
-extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-			     pud_t *pudp);
-
 static inline pud_t pud_modify(pud_t pud, pgprot_t newprot)
 {
 	return pte_pud(pte_modify(pud_pte(pud), newprot));

diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c
index 9c4427d0b187..156e385e7db4 100644
--- a/arch/riscv/mm/pgtable.c
+++ b/arch/riscv/mm/pgtable.c

@@ -154,15 +154,6 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 	return pmd;
 }
 
-pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-		      pud_t *pudp)
-{
-	VM_WARN_ON_ONCE(!pud_present(*pudp));
-	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
-
-	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
-	return old;
-}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index d5f4917c1edc..97051c02385e 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h

@@ -1387,9 +1387,6 @@ static inline pud_t pudp_establish(struct vm_area_struct *vma,
 extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
 				unsigned long address, pmd_t *pmdp);
 
-pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-		      pud_t *pudp);
-
 /*
  * Page table pages are page-aligned.  The lower half of the top
  * level is used for userspace and the top half for the kernel.

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index cb03f5a2b243..0945908631dc 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c

@@ -519,18 +519,6 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
 }
 #endif
 
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
-	defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
-pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-		     pud_t *pudp)
-{
-	VM_WARN_ON_ONCE(!pud_present(*pudp));
-	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
-	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
-	return old;
-}
-#endif
-
 /**
  * reserve_top_address - Reserve a hole in the top of the kernel address space
  * @reserve: Size of hole to reserve

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 8c093c119e5a..32173005b087 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1318,6 +1318,13 @@ extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
 				unsigned long address, pmd_t *pmdp);
 #endif
 
+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+			     pud_t *pudp);
+#endif
+#endif
+
 #ifndef __HAVE_ARCH_PTE_SAME
 static inline int pte_same(pte_t pte_a, pte_t pte_b)
 {

diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index b91b1a98029c..ac1175d9a59a 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c

@@ -217,6 +217,20 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
 }
 #endif
 
+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+		      pud_t *pudp)
+{
+	VM_WARN_ON_ONCE(!pud_present(*pudp));
+	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
+
+	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
+	return old;
+}
+#endif
+#endif
+
 #ifndef pmdp_collapse_flush
 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 			  pmd_t *pmdp)

-- 
2.43.0

[PATCH 3/3] arm64: Add support for PUD THP

From: Jinjiang Tu <hidden>
Date: 2026-09-09 09:28:55

Add the necessary page table functions to deal with PUD THP, this enables
PUD THP for DAX and pfnmap.

I tested with CONFIG_DEBUG_VM_PGTABLE and CONFIG_PAGE_TABLE_CHECK
enabled.  I wrote a test driver that invokes vmf_insert_pfn_pud() in
the huge_fault callback.  Page table setup works as expected with no
errors, and userspace read/write access to the PUD-sized mapping is
verified correct.

Signed-off-by: Jinjiang Tu <redacted>
---
 arch/arm64/Kconfig               |  1 +
 arch/arm64/include/asm/pgtable.h | 52 ++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b5a51b0ef944..8a7ca1863595 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -173,6 +173,7 @@ config ARM64
 	select HAVE_ARCH_THREAD_STRUCT_WHITELIST
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
+	select HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD if PAGE_SIZE_4KB
 	select HAVE_ARCH_VMAP_STACK
 	select HAVE_ARM_SMCCC
 	select HAVE_ASM_MODVERSIONS

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 427ea3d2bac7..fdc338970934 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h

@@ -611,6 +611,11 @@ static inline pmd_t pmd_mkhuge(pmd_t pmd)
 #define pmd_mkspecial(pmd)	pte_pmd(pte_mkspecial(pmd_pte(pmd)))
 #endif
 
+#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
+#define pud_special(pud)	pte_special(pud_pte(pud))
+#define pud_mkspecial(pud)	pte_pud(pte_mkspecial(pud_pte(pud)))
+#endif
+
 #define __pmd_to_phys(pmd)	__pte_to_phys(pmd_pte(pmd))
 #define __phys_to_pmd_val(phys)	__phys_to_pte_val(phys)
 #define pmd_pfn(pmd)		((__pmd_to_phys(pmd) & PMD_MASK) >> PAGE_SHIFT)

@@ -619,8 +624,15 @@ static inline pmd_t pmd_mkhuge(pmd_t pmd)
 #define pud_young(pud)		pte_young(pud_pte(pud))
 #define pud_mkyoung(pud)	pte_pud(pte_mkyoung(pud_pte(pud)))
 #define pud_mkwrite_novma(pud)	pte_pud(pte_mkwrite_novma(pud_pte(pud)))
+#define pud_mkwrite(pud)	pud_mkwrite_novma(pud)
 #define pud_mkvalid_k(pud)	pte_pud(pte_mkvalid_k(pud_pte(pud)))
 #define pud_write(pud)		pte_write(pud_pte(pud))
+#define pud_dirty(pud)		pte_dirty(pud_pte(pud))
+#define pud_wrprotect(pud)	pte_pud(pte_wrprotect(pud_pte(pud)))
+#define pud_mkdirty(pud)	pte_pud(pte_mkdirty(pud_pte(pud)))
+#define pud_mkold(pud)		pte_pud(pte_mkold(pud_pte(pud)))
+#define pud_mkinvalid(pud)	pte_pud(pte_mkinvalid(pud_pte(pud)))
+#define pud_mkclean(pud)	pte_pud(pte_mkclean(pud_pte(pud)))
 
 static inline pud_t pud_mkhuge(pud_t pud)
 {

@@ -871,6 +883,13 @@ static inline bool pud_leaf(pud_t pud)
 #define pud_user(pud)		pte_user(pud_pte(pud))
 #define pud_user_exec(pud)	pte_user_exec(pud_pte(pud))
 
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+static inline int pud_trans_huge(pud_t pud)
+{
+	return pud_present(pud) && !pud_table(__pud(pud_val(pud) | PTE_VALID));
+}
+#endif
+
 static inline bool pgtable_l4_enabled(void);
 
 static inline void set_pud(pud_t *pudp, pud_t pud)

@@ -1237,6 +1256,11 @@ static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 	return pte_pmd(pte_modify(pmd_pte(pmd), newprot));
 }
 
+static inline pud_t pud_modify(pud_t pud, pgprot_t newprot)
+{
+	return pte_pud(pte_modify(pud_pte(pud), newprot));
+}
+
 extern int __ptep_set_access_flags_anysz(struct vm_area_struct *vma,
 					 unsigned long address, pte_t *ptep,
 					 pte_t entry, int dirty,

@@ -1261,6 +1285,16 @@ static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
 }
 #endif
 
+#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
+static inline int pudp_set_access_flags(struct vm_area_struct *vma,
+					unsigned long address, pud_t *pudp,
+					pud_t entry, int dirty)
+{
+	return __ptep_set_access_flags_anysz(vma, address, (pte_t *)pudp,
+					     pud_pte(entry), dirty, PUD_SIZE);
+}
+#endif
+
 #ifdef CONFIG_PAGE_TABLE_CHECK
 static inline bool pte_user_accessible_page(struct mm_struct *mm, unsigned long addr, pte_t pte)
 {

@@ -1335,6 +1369,14 @@ static inline bool pmdp_test_and_clear_young(struct vm_area_struct *vma,
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG */
 
+#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
+static inline bool pudp_test_and_clear_young(struct vm_area_struct *vma,
+		unsigned long address, pud_t *pudp)
+{
+	return __ptep_test_and_clear_young(vma, address, (pte_t *)pudp);
+}
+#endif
+
 static inline pte_t __ptep_get_and_clear_anysz(struct mm_struct *mm,
 					       unsigned long address,
 					       pte_t *ptep,

@@ -1497,6 +1539,15 @@ static inline pmd_t pmdp_establish(struct vm_area_struct *vma,
 }
 #endif
 
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+static inline pud_t pudp_establish(struct vm_area_struct *vma,
+		unsigned long address, pud_t *pudp, pud_t pud)
+{
+	page_table_check_pud_set(vma->vm_mm, address, pudp, pud);
+	return __pud(xchg_relaxed(&pud_val(*pudp), pud_val(pud)));
+}
+#endif
+
 /*
  * Encode and decode a swap entry:
  *	bits 0-1:	present (must be zero)

@@ -1571,6 +1622,7 @@ static inline void update_mmu_cache_range(struct vm_fault *vmf,
 #define update_mmu_cache(vma, addr, ptep) \
 	update_mmu_cache_range(NULL, vma, addr, ptep, 1)
 #define update_mmu_cache_pmd(vma, address, pmd) do { } while (0)
+#define update_mmu_cache_pud(vma, address, pud) do { } while (0)
 
 #ifdef CONFIG_ARM64_PA_BITS_52
 #define phys_to_ttbr(addr)	(((addr) | ((addr) >> 46)) & TTBR_BADDR_MASK_52)

-- 
2.43.0

Re: [PATCH 1/3] mm: define generic pudp_invalidate() implementation

From: "David Hildenbrand (Arm)" <david@kernel.org>
Date: 2026-09-09 10:25:11

On 9/9/26 11:00, Jinjiang Tu wrote:

quoted hunk

x86 and riscv have identical pudp_invalidate() implementations. Move it to
mm/pgtable-generic.c with the __HAVE_ARCH_PUDP_INVALIDATE override guard.
PowerPC keeps its own implementation. In the later patch, arm64 will use
the generic implementation too.

No functional change intended.

Signed-off-by: Jinjiang Tu <redacted>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h |  1 +
 arch/riscv/include/asm/pgtable.h             |  3 ---
 arch/riscv/mm/pgtable.c                      |  9 ---------
 arch/x86/include/asm/pgtable.h               |  3 ---
 arch/x86/mm/pgtable.c                        | 12 ------------
 include/linux/pgtable.h                      |  7 +++++++
 mm/pgtable-generic.c                         | 14 ++++++++++++++
 7 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index f4db7d7fbd5c..55d33c5537f1 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -1419,6 +1419,7 @@ static inline pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm,
 #define __HAVE_ARCH_PMDP_INVALIDATE
 extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 			     pmd_t *pmdp);
+#define __HAVE_ARCH_PUDP_INVALIDATE
 extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
 			     pud_t *pudp);

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 40b1ed4f3ea8..327fa378032b 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h

@@ -1159,9 +1159,6 @@ static inline pud_t pud_mkinvalid(pud_t pud)
 	return __pud(pud_val(pud) & ~(_PAGE_PRESENT | _PAGE_PROT_NONE));
 }
 
-extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-			     pud_t *pudp);
-
 static inline pud_t pud_modify(pud_t pud, pgprot_t newprot)
 {
 	return pte_pud(pte_modify(pud_pte(pud), newprot));

diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c
index 9c4427d0b187..156e385e7db4 100644
--- a/arch/riscv/mm/pgtable.c
+++ b/arch/riscv/mm/pgtable.c

@@ -154,15 +154,6 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
 	return pmd;
 }
 
-pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-		      pud_t *pudp)
-{
-	VM_WARN_ON_ONCE(!pud_present(*pudp));
-	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
-
-	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
-	return old;
-}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index d5f4917c1edc..97051c02385e 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h

@@ -1387,9 +1387,6 @@ static inline pud_t pudp_establish(struct vm_area_struct *vma,
 extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
 				unsigned long address, pmd_t *pmdp);
 
-pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-		      pud_t *pudp);
-
 /*
  * Page table pages are page-aligned.  The lower half of the top
  * level is used for userspace and the top half for the kernel.

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index cb03f5a2b243..0945908631dc 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c

@@ -519,18 +519,6 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
 }
 #endif
 
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
-	defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
-pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-		     pud_t *pudp)
-{
-	VM_WARN_ON_ONCE(!pud_present(*pudp));
-	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
-	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
-	return old;
-}
-#endif
-
 /**
  * reserve_top_address - Reserve a hole in the top of the kernel address space
  * @reserve: Size of hole to reserve

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 8c093c119e5a..32173005b087 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1318,6 +1318,13 @@ extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
 				unsigned long address, pmd_t *pmdp);
 #endif
 
+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+			     pud_t *pudp);

No "extern" please.

Staring at this file, I do wonder why we are not smarter about combining blocks. E.g., here simply:

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index e3c8ab96941c5..8c9fe3bf580d4 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1229,9 +1229,9 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
-#ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
-#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+#ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
 static inline void pudp_set_wrprotect(struct mm_struct *mm,
                                      unsigned long address, pud_t *pudp)
 {

@@ -1245,9 +1245,13 @@ static inline void pudp_set_wrprotect(struct mm_struct *mm,
 {
        BUILD_BUG();
 }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 #endif
+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+               pud_t *pudp);
+#endif
+#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

quoted hunk

+#endif
+#endif
+
 #ifndef __HAVE_ARCH_PTE_SAME
 static inline int pte_same(pte_t pte_a, pte_t pte_b)
 {

diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index b91b1a98029c..ac1175d9a59a 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c

@@ -217,6 +217,20 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
 }
 #endif
 
+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD

I'd revert these and similarly see if they can be combined somehow (likely combining with
pudp_huge_clear_flush is harder as we are quite inconsistent with it, gluing it to
__HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH).

Which raises the question whether we could also piggy-back on __HAVE_ARCH_PMDP_SET_WRPROTECT
(I suspect no without a closer look.)

-- 
Cheers,

David

Re: [PATCH 1/3] mm: define generic pudp_invalidate() implementation

From: Jinjiang Tu <hidden>
Date: 2026-09-11 02:29:10

在 2026/9/9 18:24, David Hildenbrand (Arm) 写道:

On 9/9/26 11:00, Jinjiang Tu wrote:

quoted

x86 and riscv have identical pudp_invalidate() implementations. Move it to
mm/pgtable-generic.c with the __HAVE_ARCH_PUDP_INVALIDATE override guard.
PowerPC keeps its own implementation. In the later patch, arm64 will use
the generic implementation too.

No functional change intended.

Signed-off-by: Jinjiang Tu <redacted>
---
  arch/powerpc/include/asm/book3s/64/pgtable.h |  1 +
  arch/riscv/include/asm/pgtable.h             |  3 ---
  arch/riscv/mm/pgtable.c                      |  9 ---------
  arch/x86/include/asm/pgtable.h               |  3 ---
  arch/x86/mm/pgtable.c                        | 12 ------------
  include/linux/pgtable.h                      |  7 +++++++
  mm/pgtable-generic.c                         | 14 ++++++++++++++
  7 files changed, 22 insertions(+), 27 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index f4db7d7fbd5c..55d33c5537f1 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h

@@ -1419,6 +1419,7 @@ static inline pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm,
  #define __HAVE_ARCH_PMDP_INVALIDATE
  extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
  			     pmd_t *pmdp);
+#define __HAVE_ARCH_PUDP_INVALIDATE
  extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
  			     pud_t *pudp);

diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
index 40b1ed4f3ea8..327fa378032b 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h

@@ -1159,9 +1159,6 @@ static inline pud_t pud_mkinvalid(pud_t pud)
  	return __pud(pud_val(pud) & ~(_PAGE_PRESENT | _PAGE_PROT_NONE));
  }
  
-extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-			     pud_t *pudp);
-
  static inline pud_t pud_modify(pud_t pud, pgprot_t newprot)
  {
  	return pte_pud(pte_modify(pud_pte(pud), newprot));

diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c
index 9c4427d0b187..156e385e7db4 100644
--- a/arch/riscv/mm/pgtable.c
+++ b/arch/riscv/mm/pgtable.c

@@ -154,15 +154,6 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
  	return pmd;
  }
  
-pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-		      pud_t *pudp)
-{
-	VM_WARN_ON_ONCE(!pud_present(*pudp));
-	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
-
-	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
-	return old;
-}
  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  
  pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index d5f4917c1edc..97051c02385e 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h

@@ -1387,9 +1387,6 @@ static inline pud_t pudp_establish(struct vm_area_struct *vma,
  extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
  				unsigned long address, pmd_t *pmdp);
  
-pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-		      pud_t *pudp);
-
  /*
   * Page table pages are page-aligned.  The lower half of the top
   * level is used for userspace and the top half for the kernel.

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index cb03f5a2b243..0945908631dc 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c

@@ -519,18 +519,6 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
  }
  #endif
  
-#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
-	defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
-pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
-		     pud_t *pudp)
-{
-	VM_WARN_ON_ONCE(!pud_present(*pudp));
-	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
-	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
-	return old;
-}
-#endif
-
  /**
   * reserve_top_address - Reserve a hole in the top of the kernel address space
   * @reserve: Size of hole to reserve

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 8c093c119e5a..32173005b087 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1318,6 +1318,13 @@ extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
  				unsigned long address, pmd_t *pmdp);
  #endif
  
+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+			     pud_t *pudp);

No "extern" please.

Will update it.

Staring at this file, I do wonder why we are not smarter about combining blocks. E.g., here simply:'

Do you mean merging all #ifdef CONFIG_TRANSPARENT_HUGEPAGE blocks? There are many of them scattered
across include/linux/pgtable.h and arch/arm64/include/asm/pgtable.h. They are intentionally kept
separate to group the PTE, PMD, and PUD level variants of the same operation together. For example,
ptep_set_access_flags, pmdp_set_access_flags, and pudp_set_access_flags are placed adjacently.

quoted hunk

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index e3c8ab96941c5..8c9fe3bf580d4 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h

@@ -1229,9 +1229,9 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
  }
  #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
  #endif
-#ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
-#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+#ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
  static inline void pudp_set_wrprotect(struct mm_struct *mm,
                                       unsigned long address, pud_t *pudp)
  {

@@ -1245,9 +1245,13 @@ static inline void pudp_set_wrprotect(struct mm_struct *mm,
  {
         BUILD_BUG();
  }
-#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
-#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
  #endif
+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+               pud_t *pudp);
+#endif
+#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

quoted

+#endif
+#endif
+
  #ifndef __HAVE_ARCH_PTE_SAME
  static inline int pte_same(pte_t pte_a, pte_t pte_b)
  {

diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index b91b1a98029c..ac1175d9a59a 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c

@@ -217,6 +217,20 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
  }
  #endif
  
+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD

I'd revert these and similarly see if they can be combined somehow (likely combining with
pudp_huge_clear_flush is harder as we are quite inconsistent with it, gluing it to
__HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH).

Which raises the question whether we could also piggy-back on __HAVE_ARCH_PMDP_SET_WRPROTECT
(I suspect no without a closer look.)

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