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

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

[Jinjiang Tu]

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

[Jinjiang Tu]

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 <tujinjiang@huawei.com>
---
 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 2/3] arm64: simplify pmd_special and pmd_mkspecial

[Jinjiang Tu]

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 <tujinjiang@huawei.com>
---
 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 3/3] arm64: Add support for PUD THP

[Jinjiang Tu]

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 <tujinjiang@huawei.com>
---
 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

[David Hildenbrand (Arm)]

On 9/9/26 11:00, Jinjiang Tu wrote:
> 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 <tujinjiang@huawei.com>
> ---
>  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 */

> +#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

[Jinjiang Tu]

在 2026/9/9 18:24, David Hildenbrand (Arm) 写道:
> On 9/9/26 11:00, Jinjiang Tu wrote:
>> 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 <tujinjiang@huawei.com>
>> ---
>>   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.

>
> 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 */
>
>> +#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.)
>