Re: [PATCH v16 07/13] mm/page_table_check: Reinstate address parameter in [__]page_table_check_pmd_clear()

[Alexandre Ghiti <alex@ghiti.fr>]

On 8/13/25 08:26, Andrew Donnellan wrote:
> From: Rohan McLure <rmclure@linux.ibm.com>
>
> This reverts commit 1831414cd729 ("mm/page_table_check: remove unused
> parameter in [__]page_table_check_pmd_clear").
>
> Reinstate previously unused parameters for the purpose of supporting
> powerpc platforms, as many do not encode user/kernel ownership of the
> page in the pte, but instead in the address of the access.
>
> [ajd@linux.ibm.com: rebase on arm64 changes]
> Signed-off-by: Rohan McLure <rmclure@linux.ibm.com>
> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
> Acked-by: Ingo Molnar <mingo@kernel.org>  # x86
> Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
> ---
> v15: rebase
> ---
>   arch/arm64/include/asm/pgtable.h |  2 +-
>   arch/riscv/include/asm/pgtable.h |  2 +-
>   arch/x86/include/asm/pgtable.h   |  2 +-
>   include/linux/page_table_check.h | 11 +++++++----
>   include/linux/pgtable.h          |  2 +-
>   mm/page_table_check.c            |  5 +++--
>   6 files changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index 81f06e5e32b2..dfcdf051b114 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -1370,7 +1370,7 @@ static inline pte_t __ptep_get_and_clear_anysz(struct mm_struct *mm,
>   		page_table_check_pte_clear(mm, pte);
>   		break;
>   	case PMD_SIZE:
> -		page_table_check_pmd_clear(mm, pte_pmd(pte));
> +		page_table_check_pmd_clear(mm, address, pte_pmd(pte));
>   		break;
>   #ifndef __PAGETABLE_PMD_FOLDED
>   	case PUD_SIZE:
> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
> index 2484c0788012..d11fc6333606 100644
> --- a/arch/riscv/include/asm/pgtable.h
> +++ b/arch/riscv/include/asm/pgtable.h
> @@ -860,7 +860,7 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
>   {
>   	pmd_t pmd = __pmd(atomic_long_xchg((atomic_long_t *)pmdp, 0));
>   
> -	page_table_check_pmd_clear(mm, pmd);
> +	page_table_check_pmd_clear(mm, address, pmd);
>   
>   	return pmd;
>   }
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index 8b45e0c41923..b68bea15f32d 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -1318,7 +1318,7 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long
>   {
>   	pmd_t pmd = native_pmdp_get_and_clear(pmdp);
>   
> -	page_table_check_pmd_clear(mm, pmd);
> +	page_table_check_pmd_clear(mm, addr, pmd);
>   
>   	return pmd;
>   }
> diff --git a/include/linux/page_table_check.h b/include/linux/page_table_check.h
> index 808cc3a48c28..3973b69ae294 100644
> --- a/include/linux/page_table_check.h
> +++ b/include/linux/page_table_check.h
> @@ -15,7 +15,8 @@ extern struct page_ext_operations page_table_check_ops;
>   
>   void __page_table_check_zero(struct page *page, unsigned int order);
>   void __page_table_check_pte_clear(struct mm_struct *mm, pte_t pte);
> -void __page_table_check_pmd_clear(struct mm_struct *mm, pmd_t pmd);
> +void __page_table_check_pmd_clear(struct mm_struct *mm, unsigned long addr,
> +				  pmd_t pmd);
>   void __page_table_check_pud_clear(struct mm_struct *mm, unsigned long addr,
>   				  pud_t pud);
>   void __page_table_check_ptes_set(struct mm_struct *mm, unsigned long addr,
> @@ -52,12 +53,13 @@ static inline void page_table_check_pte_clear(struct mm_struct *mm, pte_t pte)
>   	__page_table_check_pte_clear(mm, pte);
>   }
>   
> -static inline void page_table_check_pmd_clear(struct mm_struct *mm, pmd_t pmd)
> +static inline void page_table_check_pmd_clear(struct mm_struct *mm,
> +					      unsigned long addr, pmd_t pmd)
>   {
>   	if (static_branch_likely(&page_table_check_disabled))
>   		return;
>   
> -	__page_table_check_pmd_clear(mm, pmd);
> +	__page_table_check_pmd_clear(mm, addr, pmd);
>   }
>   
>   static inline void page_table_check_pud_clear(struct mm_struct *mm,
> @@ -121,7 +123,8 @@ static inline void page_table_check_pte_clear(struct mm_struct *mm, pte_t pte)
>   {
>   }
>   
> -static inline void page_table_check_pmd_clear(struct mm_struct *mm, pmd_t pmd)
> +static inline void page_table_check_pmd_clear(struct mm_struct *mm,
> +					      unsigned long addr, pmd_t pmd)
>   {
>   }
>   
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 28fcff844b63..d97f40f1365d 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -648,7 +648,7 @@ static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
>   	pmd_t pmd = *pmdp;
>   
>   	pmd_clear(pmdp);
> -	page_table_check_pmd_clear(mm, pmd);
> +	page_table_check_pmd_clear(mm, address, pmd);
>   
>   	return pmd;
>   }
> diff --git a/mm/page_table_check.c b/mm/page_table_check.c
> index bd1242087a35..e8c26b616aed 100644
> --- a/mm/page_table_check.c
> +++ b/mm/page_table_check.c
> @@ -156,7 +156,8 @@ void __page_table_check_pte_clear(struct mm_struct *mm, pte_t pte)
>   }
>   EXPORT_SYMBOL(__page_table_check_pte_clear);
>   
> -void __page_table_check_pmd_clear(struct mm_struct *mm, pmd_t pmd)
> +void __page_table_check_pmd_clear(struct mm_struct *mm, unsigned long addr,
> +				  pmd_t pmd)
>   {
>   	if (&init_mm == mm)
>   		return;
> @@ -231,7 +232,7 @@ void __page_table_check_pmds_set(struct mm_struct *mm, unsigned long addr,
>   	page_table_check_pmd_flags(pmd);
>   
>   	for (i = 0; i < nr; i++)
> -		__page_table_check_pmd_clear(mm, *(pmdp + i));
> +		__page_table_check_pmd_clear(mm, addr + PMD_SIZE * i, *(pmdp + i));
>   	if (pmd_user_accessible_page(pmd))
>   		page_table_check_set(pmd_pfn(pmd), stride * nr, pmd_write(pmd));
>   }


Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com> # riscv

Thanks,

Alex