Re: [PATCH v6 24/26] mm: Remove devmap related functions and page table bits

Huacai Chen
2025-01-11T10:08:31Z

Hi, Alistair,

I think the last two patches can be squashed into this one.

Huacai

On Fri, Jan 10, 2025 at 2:03 PM Alistair Popple <apopple@nvidia.com> wrote:
>
> Now that DAX and all other reference counts to ZONE_DEVICE pages are
> managed normally there is no need for the special devmap PTE/PMD/PUD
> page table bits. So drop all references to these, freeing up a
> software defined page table bit on architectures supporting it.
>
> Signed-off-by: Alistair Popple <apopple@nvidia.com>
> Acked-by: Will Deacon <will@kernel.org> # arm64
> ---
> Documentation/mm/arch_pgtable_helpers.rst | 6 +--
> arch/arm64/Kconfig | 1 +-
> arch/arm64/include/asm/pgtable-prot.h | 1 +-
> arch/arm64/include/asm/pgtable.h | 24 +--------
> arch/powerpc/Kconfig | 1 +-
> arch/powerpc/include/asm/book3s/64/hash-4k.h | 6 +--
> arch/powerpc/include/asm/book3s/64/hash-64k.h | 7 +--
> arch/powerpc/include/asm/book3s/64/pgtable.h | 53 +------------------
> arch/powerpc/include/asm/book3s/64/radix.h | 14 +-----
> arch/x86/Kconfig | 1 +-
> arch/x86/include/asm/pgtable.h | 51 +-----------------
> arch/x86/include/asm/pgtable_types.h | 5 +--
> include/linux/mm.h | 7 +--
> include/linux/pfn_t.h | 20 +-------
> include/linux/pgtable.h | 19 +------
> mm/Kconfig | 4 +-
> mm/debug_vm_pgtable.c | 59 +--------------------
> mm/hmm.c | 3 +-
> 18 files changed, 11 insertions(+), 271 deletions(-)
>
> diff --git a/Documentation/mm/arch_pgtable_helpers.rst b/Documentation/mm/arch_pgtable_helpers.rst
> index af24516..c88c7fa 100644
> --- a/Documentation/mm/arch_pgtable_helpers.rst
> +++ b/Documentation/mm/arch_pgtable_helpers.rst
> @@ -30,8 +30,6 @@ PTE Page Table Helpers
> +---------------------------+--------------------------------------------------+
> | pte_protnone | Tests a PROT_NONE PTE |
> +---------------------------+--------------------------------------------------+
> -| pte_devmap | Tests a ZONE_DEVICE mapped PTE |
> -+---------------------------+--------------------------------------------------+
> | pte_soft_dirty | Tests a soft dirty PTE |
> +---------------------------+--------------------------------------------------+
> | pte_swp_soft_dirty | Tests a soft dirty swapped PTE |
> @@ -104,8 +102,6 @@ PMD Page Table Helpers
> +---------------------------+--------------------------------------------------+
> | pmd_protnone | Tests a PROT_NONE PMD |
> +---------------------------+--------------------------------------------------+
> -| pmd_devmap | Tests a ZONE_DEVICE mapped PMD |
> -+---------------------------+--------------------------------------------------+
> | pmd_soft_dirty | Tests a soft dirty PMD |
> +---------------------------+--------------------------------------------------+
> | pmd_swp_soft_dirty | Tests a soft dirty swapped PMD |
> @@ -177,8 +173,6 @@ PUD Page Table Helpers
> +---------------------------+--------------------------------------------------+
> | pud_write | Tests a writable PUD |
> +---------------------------+--------------------------------------------------+
> -| pud_devmap | Tests a ZONE_DEVICE mapped PUD |
> -+---------------------------+--------------------------------------------------+
> | pud_mkyoung | Creates a young PUD |
> +---------------------------+--------------------------------------------------+
> | pud_mkold | Creates an old PUD |
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 39310a4..81855d1 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -41,7 +41,6 @@ config ARM64
> select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
> select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> select ARCH_HAS_NONLEAF_PMD_YOUNG if ARM64_HAFT
> - select ARCH_HAS_PTE_DEVMAP
> select ARCH_HAS_PTE_SPECIAL
> select ARCH_HAS_HW_PTE_YOUNG
> select ARCH_HAS_SETUP_DMA_OPS
> diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h
> index 9f9cf13..49b51df 100644
> --- a/arch/arm64/include/asm/pgtable-prot.h
> +++ b/arch/arm64/include/asm/pgtable-prot.h
> @@ -17,7 +17,6 @@
> #define PTE_SWP_EXCLUSIVE (_AT(pteval_t, 1) << 2) /* only for swp ptes */
> #define PTE_DIRTY (_AT(pteval_t, 1) << 55)
> #define PTE_SPECIAL (_AT(pteval_t, 1) << 56)
> -#define PTE_DEVMAP (_AT(pteval_t, 1) << 57)
>
> /*
> * PTE_PRESENT_INVALID=1 & PTE_VALID=0 indicates that the pte's fields should be
> diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
> index f8dac66..ea34e51 100644
> --- a/arch/arm64/include/asm/pgtable.h
> +++ b/arch/arm64/include/asm/pgtable.h
> @@ -108,7 +108,6 @@ static inline pteval_t __phys_to_pte_val(phys_addr_t phys)
> #define pte_user(pte) (!!(pte_val(pte) & PTE_USER))
> #define pte_user_exec(pte) (!(pte_val(pte) & PTE_UXN))
> #define pte_cont(pte) (!!(pte_val(pte) & PTE_CONT))
> -#define pte_devmap(pte) (!!(pte_val(pte) & PTE_DEVMAP))
> #define pte_tagged(pte) ((pte_val(pte) & PTE_ATTRINDX_MASK) == \
> PTE_ATTRINDX(MT_NORMAL_TAGGED))
>
> @@ -290,11 +289,6 @@ static inline pmd_t pmd_mkcont(pmd_t pmd)
> return __pmd(pmd_val(pmd) | PMD_SECT_CONT);
> }
>
> -static inline pte_t pte_mkdevmap(pte_t pte)
> -{
> - return set_pte_bit(pte, __pgprot(PTE_DEVMAP | PTE_SPECIAL));
> -}
> -
> #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_WP
> static inline int pte_uffd_wp(pte_t pte)
> {
> @@ -587,14 +581,6 @@ static inline int pmd_trans_huge(pmd_t pmd)
>
> #define pmd_mkhuge(pmd) (__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
>
> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> -#define pmd_devmap(pmd) pte_devmap(pmd_pte(pmd))
> -#endif
> -static inline pmd_t pmd_mkdevmap(pmd_t pmd)
> -{
> - return pte_pmd(set_pte_bit(pmd_pte(pmd), __pgprot(PTE_DEVMAP)));
> -}
> -
> #ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
> #define pmd_special(pte) (!!((pmd_val(pte) & PTE_SPECIAL)))
> static inline pmd_t pmd_mkspecial(pmd_t pmd)
> @@ -1195,16 +1181,6 @@ static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
> return __ptep_set_access_flags(vma, address, (pte_t *)pmdp,
> pmd_pte(entry), dirty);
> }
> -
> -static inline int pud_devmap(pud_t pud)
> -{
> - return 0;
> -}
> -
> -static inline int pgd_devmap(pgd_t pgd)
> -{
> - return 0;
> -}
> #endif
>
> #ifdef CONFIG_PAGE_TABLE_CHECK
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index da0ac66..3e85f89 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -147,7 +147,6 @@ config PPC
> select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> select ARCH_HAS_PHYS_TO_DMA
> select ARCH_HAS_PMEM_API
> - select ARCH_HAS_PTE_DEVMAP if PPC_BOOK3S_64
> select ARCH_HAS_PTE_SPECIAL
> select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64
> select ARCH_HAS_SET_MEMORY
> diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h
> index c3efaca..b0546d3 100644
> --- a/arch/powerpc/include/asm/book3s/64/hash-4k.h
> +++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h
> @@ -160,12 +160,6 @@ extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
> extern int hash__has_transparent_hugepage(void);
> #endif
>
> -static inline pmd_t hash__pmd_mkdevmap(pmd_t pmd)
> -{
> - BUG();
> - return pmd;
> -}
> -
> #endif /* !__ASSEMBLY__ */
>
> #endif /* _ASM_POWERPC_BOOK3S_64_HASH_4K_H */
> diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h
> index 0bf6fd0..0fb5b7d 100644
> --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h
> +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h
> @@ -259,7 +259,7 @@ static inline void mark_hpte_slot_valid(unsigned char *hpte_slot_array,
> */
> static inline int hash__pmd_trans_huge(pmd_t pmd)
> {
> - return !!((pmd_val(pmd) & (_PAGE_PTE | H_PAGE_THP_HUGE | _PAGE_DEVMAP)) ==
> + return !!((pmd_val(pmd) & (_PAGE_PTE | H_PAGE_THP_HUGE)) ==
> (_PAGE_PTE | H_PAGE_THP_HUGE));
> }
>
> @@ -281,11 +281,6 @@ extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm,
> extern int hash__has_transparent_hugepage(void);
> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>
> -static inline pmd_t hash__pmd_mkdevmap(pmd_t pmd)
> -{
> - return __pmd(pmd_val(pmd) | (_PAGE_PTE | H_PAGE_THP_HUGE | _PAGE_DEVMAP));
> -}
> -
> #endif /* __ASSEMBLY__ */
>
> #endif /* _ASM_POWERPC_BOOK3S_64_HASH_64K_H */
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index 6d98e6f..1d98d0a 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -88,7 +88,6 @@
>
> #define _PAGE_SOFT_DIRTY _RPAGE_SW3 /* software: software dirty tracking */
> #define _PAGE_SPECIAL _RPAGE_SW2 /* software: special page */
> -#define _PAGE_DEVMAP _RPAGE_SW1 /* software: ZONE_DEVICE page */
>
> /*
> * Drivers request for cache inhibited pte mapping using _PAGE_NO_CACHE
> @@ -109,7 +108,7 @@
> */
> #define _HPAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
> _PAGE_ACCESSED | H_PAGE_THP_HUGE | _PAGE_PTE | \
> - _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
> + _PAGE_SOFT_DIRTY)
> /*
> * user access blocked by key
> */
> @@ -123,7 +122,7 @@
> */
> #define _PAGE_CHG_MASK (PTE_RPN_MASK | _PAGE_HPTEFLAGS | _PAGE_DIRTY | \
> _PAGE_ACCESSED | _PAGE_SPECIAL | _PAGE_PTE | \
> - _PAGE_SOFT_DIRTY | _PAGE_DEVMAP)
> + _PAGE_SOFT_DIRTY)
>
> /*
> * We define 2 sets of base prot bits, one for basic pages (ie,
> @@ -609,24 +608,6 @@ static inline pte_t pte_mkhuge(pte_t pte)
> return pte;
> }
>
> -static inline pte_t pte_mkdevmap(pte_t pte)
> -{
> - return __pte_raw(pte_raw(pte) | cpu_to_be64(_PAGE_SPECIAL | _PAGE_DEVMAP));
> -}
> -
> -/*
> - * This is potentially called with a pmd as the argument, in which case it's not
> - * safe to check _PAGE_DEVMAP unless we also confirm that _PAGE_PTE is set.
> - * That's because the bit we use for _PAGE_DEVMAP is not reserved for software
> - * use in page directory entries (ie. non-ptes).
> - */
> -static inline int pte_devmap(pte_t pte)
> -{
> - __be64 mask = cpu_to_be64(_PAGE_DEVMAP | _PAGE_PTE);
> -
> - return (pte_raw(pte) & mask) == mask;
> -}
> -
> static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
> {
> /* FIXME!! check whether this need to be a conditional */
> @@ -1380,36 +1361,6 @@ static inline bool arch_needs_pgtable_deposit(void)
> }
> extern void serialize_against_pte_lookup(struct mm_struct *mm);
>
> -
> -static inline pmd_t pmd_mkdevmap(pmd_t pmd)
> -{
> - if (radix_enabled())
> - return radix__pmd_mkdevmap(pmd);
> - return hash__pmd_mkdevmap(pmd);
> -}
> -
> -static inline pud_t pud_mkdevmap(pud_t pud)
> -{
> - if (radix_enabled())
> - return radix__pud_mkdevmap(pud);
> - BUG();
> - return pud;
> -}
> -
> -static inline int pmd_devmap(pmd_t pmd)
> -{
> - return pte_devmap(pmd_pte(pmd));
> -}
> -
> -static inline int pud_devmap(pud_t pud)
> -{
> - return pte_devmap(pud_pte(pud));
> -}
> -
> -static inline int pgd_devmap(pgd_t pgd)
> -{
> - return 0;
> -}
> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>
> #define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
> diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
> index 8f55ff7..df23a82 100644
> --- a/arch/powerpc/include/asm/book3s/64/radix.h
> +++ b/arch/powerpc/include/asm/book3s/64/radix.h
> @@ -264,7 +264,7 @@ static inline int radix__p4d_bad(p4d_t p4d)
>
> static inline int radix__pmd_trans_huge(pmd_t pmd)
> {
> - return (pmd_val(pmd) & (_PAGE_PTE | _PAGE_DEVMAP)) == _PAGE_PTE;
> + return (pmd_val(pmd) & _PAGE_PTE) == _PAGE_PTE;
> }
>
> static inline pmd_t radix__pmd_mkhuge(pmd_t pmd)
> @@ -274,7 +274,7 @@ static inline pmd_t radix__pmd_mkhuge(pmd_t pmd)
>
> static inline int radix__pud_trans_huge(pud_t pud)
> {
> - return (pud_val(pud) & (_PAGE_PTE | _PAGE_DEVMAP)) == _PAGE_PTE;
> + return (pud_val(pud) & _PAGE_PTE) == _PAGE_PTE;
> }
>
> static inline pud_t radix__pud_mkhuge(pud_t pud)
> @@ -315,16 +315,6 @@ static inline int radix__has_transparent_pud_hugepage(void)
> }
> #endif
>
> -static inline pmd_t radix__pmd_mkdevmap(pmd_t pmd)
> -{
> - return __pmd(pmd_val(pmd) | (_PAGE_PTE | _PAGE_DEVMAP));
> -}
> -
> -static inline pud_t radix__pud_mkdevmap(pud_t pud)
> -{
> - return __pud(pud_val(pud) | (_PAGE_PTE | _PAGE_DEVMAP));
> -}
> -
> struct vmem_altmap;
> struct dev_pagemap;
> extern int __meminit radix__vmemmap_create_mapping(unsigned long start,
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 77f001c..acac373 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -97,7 +97,6 @@ config X86
> select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
> select ARCH_HAS_PMEM_API if X86_64
> select ARCH_HAS_PREEMPT_LAZY
> - select ARCH_HAS_PTE_DEVMAP if X86_64
> select ARCH_HAS_PTE_SPECIAL
> select ARCH_HAS_HW_PTE_YOUNG
> select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2
> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
> index 593f10a..77705be 100644
> --- a/arch/x86/include/asm/pgtable.h
> +++ b/arch/x86/include/asm/pgtable.h
> @@ -308,16 +308,15 @@ static inline bool pmd_leaf(pmd_t pte)
> }
>
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> -/* NOTE: when predicate huge page, consider also pmd_devmap, or use pmd_leaf */
> static inline int pmd_trans_huge(pmd_t pmd)
> {
> - return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE;
> + return (pmd_val(pmd) & _PAGE_PSE) == _PAGE_PSE;
> }
>
> #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
> static inline int pud_trans_huge(pud_t pud)
> {
> - return (pud_val(pud) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE;
> + return (pud_val(pud) & _PAGE_PSE) == _PAGE_PSE;
> }
> #endif
>
> @@ -327,24 +326,6 @@ static inline int has_transparent_hugepage(void)
> return boot_cpu_has(X86_FEATURE_PSE);
> }
>
> -#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
> -static inline int pmd_devmap(pmd_t pmd)
> -{
> - return !!(pmd_val(pmd) & _PAGE_DEVMAP);
> -}
> -
> -#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
> -static inline int pud_devmap(pud_t pud)
> -{
> - return !!(pud_val(pud) & _PAGE_DEVMAP);
> -}
> -#else
> -static inline int pud_devmap(pud_t pud)
> -{
> - return 0;
> -}
> -#endif
> -
> #ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
> static inline bool pmd_special(pmd_t pmd)
> {
> @@ -368,12 +349,6 @@ static inline pud_t pud_mkspecial(pud_t pud)
> return pud_set_flags(pud, _PAGE_SPECIAL);
> }
> #endif /* CONFIG_ARCH_SUPPORTS_PUD_PFNMAP */
> -
> -static inline int pgd_devmap(pgd_t pgd)
> -{
> - return 0;
> -}
> -#endif
> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>
> static inline pte_t pte_set_flags(pte_t pte, pteval_t set)
> @@ -534,11 +509,6 @@ static inline pte_t pte_mkspecial(pte_t pte)
> return pte_set_flags(pte, _PAGE_SPECIAL);
> }
>
> -static inline pte_t pte_mkdevmap(pte_t pte)
> -{
> - return pte_set_flags(pte, _PAGE_SPECIAL|_PAGE_DEVMAP);
> -}
> -
> /* See comments above mksaveddirty_shift() */
> static inline pmd_t pmd_mksaveddirty(pmd_t pmd)
> {
> @@ -610,11 +580,6 @@ static inline pmd_t pmd_mkwrite_shstk(pmd_t pmd)
> return pmd_set_flags(pmd, _PAGE_DIRTY);
> }
>
> -static inline pmd_t pmd_mkdevmap(pmd_t pmd)
> -{
> - return pmd_set_flags(pmd, _PAGE_DEVMAP);
> -}
> -
> static inline pmd_t pmd_mkhuge(pmd_t pmd)
> {
> return pmd_set_flags(pmd, _PAGE_PSE);
> @@ -680,11 +645,6 @@ static inline pud_t pud_mkdirty(pud_t pud)
> return pud_mksaveddirty(pud);
> }
>
> -static inline pud_t pud_mkdevmap(pud_t pud)
> -{
> - return pud_set_flags(pud, _PAGE_DEVMAP);
> -}
> -
> static inline pud_t pud_mkhuge(pud_t pud)
> {
> return pud_set_flags(pud, _PAGE_PSE);
> @@ -1012,13 +972,6 @@ static inline int pte_present(pte_t a)
> return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE);
> }
>
> -#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
> -static inline int pte_devmap(pte_t a)
> -{
> - return (pte_flags(a) & _PAGE_DEVMAP) == _PAGE_DEVMAP;
> -}
> -#endif
> -
> #define pte_accessible pte_accessible
> static inline bool pte_accessible(struct mm_struct *mm, pte_t a)
> {
> diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
> index 4b80453..e4c7b51 100644
> --- a/arch/x86/include/asm/pgtable_types.h
> +++ b/arch/x86/include/asm/pgtable_types.h
> @@ -33,7 +33,6 @@
> #define _PAGE_BIT_CPA_TEST _PAGE_BIT_SOFTW1
> #define _PAGE_BIT_UFFD_WP _PAGE_BIT_SOFTW2 /* userfaultfd wrprotected */
> #define _PAGE_BIT_SOFT_DIRTY _PAGE_BIT_SOFTW3 /* software dirty tracking */
> -#define _PAGE_BIT_DEVMAP _PAGE_BIT_SOFTW4
>
> #ifdef CONFIG_X86_64
> #define _PAGE_BIT_SAVED_DIRTY _PAGE_BIT_SOFTW5 /* Saved Dirty bit (leaf) */
> @@ -119,11 +118,9 @@
>
> #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
> #define _PAGE_NX (_AT(pteval_t, 1) << _PAGE_BIT_NX)
> -#define _PAGE_DEVMAP (_AT(u64, 1) << _PAGE_BIT_DEVMAP)
> #define _PAGE_SOFTW4 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW4)
> #else
> #define _PAGE_NX (_AT(pteval_t, 0))
> -#define _PAGE_DEVMAP (_AT(pteval_t, 0))
> #define _PAGE_SOFTW4 (_AT(pteval_t, 0))
> #endif
>
> @@ -152,7 +149,7 @@
> #define _COMMON_PAGE_CHG_MASK (PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT | \
> _PAGE_SPECIAL | _PAGE_ACCESSED | \
> _PAGE_DIRTY_BITS | _PAGE_SOFT_DIRTY | \
> - _PAGE_DEVMAP | _PAGE_CC | _PAGE_UFFD_WP)
> + _PAGE_CC | _PAGE_UFFD_WP)
> #define _PAGE_CHG_MASK (_COMMON_PAGE_CHG_MASK | _PAGE_PAT)
> #define _HPAGE_CHG_MASK (_COMMON_PAGE_CHG_MASK | _PAGE_PSE | _PAGE_PAT_LARGE)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index a734278..23c4e9b 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2769,13 +2769,6 @@ static inline pud_t pud_mkspecial(pud_t pud)
> }
> #endif /* CONFIG_ARCH_SUPPORTS_PUD_PFNMAP */
>
> -#ifndef CONFIG_ARCH_HAS_PTE_DEVMAP
> -static inline int pte_devmap(pte_t pte)
> -{
> - return 0;
> -}
> -#endif
> -
> extern pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
> spinlock_t **ptl);
> static inline pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
> diff --git a/include/linux/pfn_t.h b/include/linux/pfn_t.h
> index 2d91482..0100ad8 100644
> --- a/include/linux/pfn_t.h
> +++ b/include/linux/pfn_t.h
> @@ -97,26 +97,6 @@ static inline pud_t pfn_t_pud(pfn_t pfn, pgprot_t pgprot)
> #endif
> #endif
>
> -#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
> -static inline bool pfn_t_devmap(pfn_t pfn)
> -{
> - const u64 flags = PFN_DEV|PFN_MAP;
> -
> - return (pfn.val & flags) == flags;
> -}
> -#else
> -static inline bool pfn_t_devmap(pfn_t pfn)
> -{
> - return false;
> -}
> -pte_t pte_mkdevmap(pte_t pte);
> -pmd_t pmd_mkdevmap(pmd_t pmd);
> -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
> - defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
> -pud_t pud_mkdevmap(pud_t pud);
> -#endif
> -#endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
> -
> #ifdef CONFIG_ARCH_HAS_PTE_SPECIAL
> static inline bool pfn_t_special(pfn_t pfn)
> {
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 00e4a06..1c377de 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -1606,21 +1606,6 @@ static inline int pud_write(pud_t pud)
> }
> #endif /* pud_write */
>
> -#if !defined(CONFIG_ARCH_HAS_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
> -static inline int pmd_devmap(pmd_t pmd)
> -{
> - return 0;
> -}
> -static inline int pud_devmap(pud_t pud)
> -{
> - return 0;
> -}
> -static inline int pgd_devmap(pgd_t pgd)
> -{
> - return 0;
> -}
> -#endif
> -
> #if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \
> !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
> static inline int pud_trans_huge(pud_t pud)
> @@ -1875,8 +1860,8 @@ typedef unsigned int pgtbl_mod_mask;
> * - It should contain a huge PFN, which points to a huge page larger than
> * PAGE_SIZE of the platform. The PFN format isn't important here.
> *
> - * - It should cover all kinds of huge mappings (e.g., pXd_trans_huge(),
> - * pXd_devmap(), or hugetlb mappings).
> + * - It should cover all kinds of huge mappings (i.e. pXd_trans_huge()
> + * or hugetlb mappings).
> */
> #ifndef pgd_leaf
> #define pgd_leaf(x) false
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 7949ab1..e1d0981 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -1044,9 +1044,6 @@ config ARCH_HAS_CURRENT_STACK_POINTER
> register alias named "current_stack_pointer", this config can be
> selected.
>
> -config ARCH_HAS_PTE_DEVMAP
> - bool
> -
> config ARCH_HAS_ZONE_DMA_SET
> bool
>
> @@ -1064,7 +1061,6 @@ config ZONE_DEVICE
> depends on MEMORY_HOTPLUG
> depends on MEMORY_HOTREMOVE
> depends on SPARSEMEM_VMEMMAP
> - depends on ARCH_HAS_PTE_DEVMAP
> select XARRAY_MULTI
>
> help
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index bc748f7..cf5ff92 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -348,12 +348,6 @@ static void __init pud_advanced_tests(struct pgtable_debug_args *args)
> vaddr &= HPAGE_PUD_MASK;
>
> pud = pfn_pud(args->pud_pfn, args->page_prot);
> - /*
> - * Some architectures have debug checks to make sure
> - * huge pud mapping are only found with devmap entries
> - * For now test with only devmap entries.
> - */
> - pud = pud_mkdevmap(pud);
> set_pud_at(args->mm, vaddr, args->pudp, pud);
> flush_dcache_page(page);
> pudp_set_wrprotect(args->mm, vaddr, args->pudp);
> @@ -366,7 +360,6 @@ static void __init pud_advanced_tests(struct pgtable_debug_args *args)
> WARN_ON(!pud_none(pud));
> #endif /* __PAGETABLE_PMD_FOLDED */
> pud = pfn_pud(args->pud_pfn, args->page_prot);
> - pud = pud_mkdevmap(pud);
> pud = pud_wrprotect(pud);
> pud = pud_mkclean(pud);
> set_pud_at(args->mm, vaddr, args->pudp, pud);
> @@ -384,7 +377,6 @@ static void __init pud_advanced_tests(struct pgtable_debug_args *args)
> #endif /* __PAGETABLE_PMD_FOLDED */
>
> pud = pfn_pud(args->pud_pfn, args->page_prot);
> - pud = pud_mkdevmap(pud);
> pud = pud_mkyoung(pud);
> set_pud_at(args->mm, vaddr, args->pudp, pud);
> flush_dcache_page(page);
> @@ -693,53 +685,6 @@ static void __init pmd_protnone_tests(struct pgtable_debug_args *args)
> static void __init pmd_protnone_tests(struct pgtable_debug_args *args) { }
> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>
> -#ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
> -static void __init pte_devmap_tests(struct pgtable_debug_args *args)
> -{
> - pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
> -
> - pr_debug("Validating PTE devmap\n");
> - WARN_ON(!pte_devmap(pte_mkdevmap(pte)));
> -}
> -
> -#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> -static void __init pmd_devmap_tests(struct pgtable_debug_args *args)
> -{
> - pmd_t pmd;
> -
> - if (!has_transparent_hugepage())
> - return;
> -
> - pr_debug("Validating PMD devmap\n");
> - pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
> - WARN_ON(!pmd_devmap(pmd_mkdevmap(pmd)));
> -}
> -
> -#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
> -static void __init pud_devmap_tests(struct pgtable_debug_args *args)
> -{
> - pud_t pud;
> -
> - if (!has_transparent_pud_hugepage())
> - return;
> -
> - pr_debug("Validating PUD devmap\n");
> - pud = pfn_pud(args->fixed_pud_pfn, args->page_prot);
> - WARN_ON(!pud_devmap(pud_mkdevmap(pud)));
> -}
> -#else /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
> -static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
> -#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
> -#else /* CONFIG_TRANSPARENT_HUGEPAGE */
> -static void __init pmd_devmap_tests(struct pgtable_debug_args *args) { }
> -static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
> -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> -#else
> -static void __init pte_devmap_tests(struct pgtable_debug_args *args) { }
> -static void __init pmd_devmap_tests(struct pgtable_debug_args *args) { }
> -static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
> -#endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
> -
> static void __init pte_soft_dirty_tests(struct pgtable_debug_args *args)
> {
> pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
> @@ -1341,10 +1286,6 @@ static int __init debug_vm_pgtable(void)
> pte_protnone_tests(&args);
> pmd_protnone_tests(&args);
>
> - pte_devmap_tests(&args);
> - pmd_devmap_tests(&args);
> - pud_devmap_tests(&args);
> -
> pte_soft_dirty_tests(&args);
> pmd_soft_dirty_tests(&args);
> pte_swap_soft_dirty_tests(&args);
> diff --git a/mm/hmm.c b/mm/hmm.c
> index 285578e..2a12879 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -395,8 +395,7 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
> return 0;
> }
>
> -#if defined(CONFIG_ARCH_HAS_PTE_DEVMAP) && \
> - defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
> +#if defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
> static inline unsigned long pud_to_hmm_pfn_flags(struct hmm_range *range,
> pud_t pud)
> {
> --
> git-series 0.9.1