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- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef _LINUX_SWAPOPS_H
- #define _LINUX_SWAPOPS_H
- #include <linux/radix-tree.h>
- #include <linux/bug.h>
- #include <linux/mm_types.h>
- #ifdef CONFIG_MMU
- #ifdef CONFIG_SWAP
- #include <linux/swapfile.h>
- #endif /* CONFIG_SWAP */
- /*
- * swapcache pages are stored in the swapper_space radix tree. We want to
- * get good packing density in that tree, so the index should be dense in
- * the low-order bits.
- *
- * We arrange the `type' and `offset' fields so that `type' is at the six
- * high-order bits of the swp_entry_t and `offset' is right-aligned in the
- * remaining bits. Although `type' itself needs only five bits, we allow for
- * shmem/tmpfs to shift it all up a further one bit: see swp_to_radix_entry().
- *
- * swp_entry_t's are *never* stored anywhere in their arch-dependent format.
- */
- #define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
- #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
- /*
- * Definitions only for PFN swap entries (see is_pfn_swap_entry()). To
- * store PFN, we only need SWP_PFN_BITS bits. Each of the pfn swap entries
- * can use the extra bits to store other information besides PFN.
- */
- #ifdef MAX_PHYSMEM_BITS
- #define SWP_PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT)
- #else /* MAX_PHYSMEM_BITS */
- #define SWP_PFN_BITS min_t(int, \
- sizeof(phys_addr_t) * 8 - PAGE_SHIFT, \
- SWP_TYPE_SHIFT)
- #endif /* MAX_PHYSMEM_BITS */
- #define SWP_PFN_MASK (BIT(SWP_PFN_BITS) - 1)
- /**
- * Migration swap entry specific bitfield definitions. Layout:
- *
- * |----------+--------------------|
- * | swp_type | swp_offset |
- * |----------+--------+-+-+-------|
- * | | resv |D|A| PFN |
- * |----------+--------+-+-+-------|
- *
- * @SWP_MIG_YOUNG_BIT: Whether the page used to have young bit set (bit A)
- * @SWP_MIG_DIRTY_BIT: Whether the page used to have dirty bit set (bit D)
- *
- * Note: A/D bits will be stored in migration entries iff there're enough
- * free bits in arch specific swp offset. By default we'll ignore A/D bits
- * when migrating a page. Please refer to migration_entry_supports_ad()
- * for more information. If there're more bits besides PFN and A/D bits,
- * they should be reserved and always be zeros.
- */
- #define SWP_MIG_YOUNG_BIT (SWP_PFN_BITS)
- #define SWP_MIG_DIRTY_BIT (SWP_PFN_BITS + 1)
- #define SWP_MIG_TOTAL_BITS (SWP_PFN_BITS + 2)
- #define SWP_MIG_YOUNG BIT(SWP_MIG_YOUNG_BIT)
- #define SWP_MIG_DIRTY BIT(SWP_MIG_DIRTY_BIT)
- static inline bool is_pfn_swap_entry(swp_entry_t entry);
- /* Clear all flags but only keep swp_entry_t related information */
- static inline pte_t pte_swp_clear_flags(pte_t pte)
- {
- if (pte_swp_exclusive(pte))
- pte = pte_swp_clear_exclusive(pte);
- if (pte_swp_soft_dirty(pte))
- pte = pte_swp_clear_soft_dirty(pte);
- if (pte_swp_uffd_wp(pte))
- pte = pte_swp_clear_uffd_wp(pte);
- return pte;
- }
- /*
- * Store a type+offset into a swp_entry_t in an arch-independent format
- */
- static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
- {
- swp_entry_t ret;
- ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
- return ret;
- }
- /*
- * Extract the `type' field from a swp_entry_t. The swp_entry_t is in
- * arch-independent format
- */
- static inline unsigned swp_type(swp_entry_t entry)
- {
- return (entry.val >> SWP_TYPE_SHIFT);
- }
- /*
- * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in
- * arch-independent format
- */
- static inline pgoff_t swp_offset(swp_entry_t entry)
- {
- return entry.val & SWP_OFFSET_MASK;
- }
- /*
- * This should only be called upon a pfn swap entry to get the PFN stored
- * in the swap entry. Please refers to is_pfn_swap_entry() for definition
- * of pfn swap entry.
- */
- static inline unsigned long swp_offset_pfn(swp_entry_t entry)
- {
- VM_BUG_ON(!is_pfn_swap_entry(entry));
- return swp_offset(entry) & SWP_PFN_MASK;
- }
- /* check whether a pte points to a swap entry */
- static inline int is_swap_pte(pte_t pte)
- {
- return !pte_none(pte) && !pte_present(pte);
- }
- /*
- * Convert the arch-dependent pte representation of a swp_entry_t into an
- * arch-independent swp_entry_t.
- */
- static inline swp_entry_t pte_to_swp_entry(pte_t pte)
- {
- swp_entry_t arch_entry;
- pte = pte_swp_clear_flags(pte);
- arch_entry = __pte_to_swp_entry(pte);
- return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
- }
- /*
- * Convert the arch-independent representation of a swp_entry_t into the
- * arch-dependent pte representation.
- */
- static inline pte_t swp_entry_to_pte(swp_entry_t entry)
- {
- swp_entry_t arch_entry;
- arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
- return __swp_entry_to_pte(arch_entry);
- }
- static inline swp_entry_t radix_to_swp_entry(void *arg)
- {
- swp_entry_t entry;
- entry.val = xa_to_value(arg);
- return entry;
- }
- static inline void *swp_to_radix_entry(swp_entry_t entry)
- {
- return xa_mk_value(entry.val);
- }
- static inline swp_entry_t make_swapin_error_entry(struct page *page)
- {
- return swp_entry(SWP_SWAPIN_ERROR, page_to_pfn(page));
- }
- static inline int is_swapin_error_entry(swp_entry_t entry)
- {
- return swp_type(entry) == SWP_SWAPIN_ERROR;
- }
- #if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
- static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
- {
- return swp_entry(SWP_DEVICE_READ, offset);
- }
- static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset)
- {
- return swp_entry(SWP_DEVICE_WRITE, offset);
- }
- static inline bool is_device_private_entry(swp_entry_t entry)
- {
- int type = swp_type(entry);
- return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE;
- }
- static inline bool is_writable_device_private_entry(swp_entry_t entry)
- {
- return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
- }
- static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
- {
- return swp_entry(SWP_DEVICE_EXCLUSIVE_READ, offset);
- }
- static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
- {
- return swp_entry(SWP_DEVICE_EXCLUSIVE_WRITE, offset);
- }
- static inline bool is_device_exclusive_entry(swp_entry_t entry)
- {
- return swp_type(entry) == SWP_DEVICE_EXCLUSIVE_READ ||
- swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE;
- }
- static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
- {
- return unlikely(swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE);
- }
- #else /* CONFIG_DEVICE_PRIVATE */
- static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
- {
- return swp_entry(0, 0);
- }
- static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset)
- {
- return swp_entry(0, 0);
- }
- static inline bool is_device_private_entry(swp_entry_t entry)
- {
- return false;
- }
- static inline bool is_writable_device_private_entry(swp_entry_t entry)
- {
- return false;
- }
- static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
- {
- return swp_entry(0, 0);
- }
- static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
- {
- return swp_entry(0, 0);
- }
- static inline bool is_device_exclusive_entry(swp_entry_t entry)
- {
- return false;
- }
- static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
- {
- return false;
- }
- #endif /* CONFIG_DEVICE_PRIVATE */
- #ifdef CONFIG_MIGRATION
- static inline int is_migration_entry(swp_entry_t entry)
- {
- return unlikely(swp_type(entry) == SWP_MIGRATION_READ ||
- swp_type(entry) == SWP_MIGRATION_READ_EXCLUSIVE ||
- swp_type(entry) == SWP_MIGRATION_WRITE);
- }
- static inline int is_writable_migration_entry(swp_entry_t entry)
- {
- return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE);
- }
- static inline int is_readable_migration_entry(swp_entry_t entry)
- {
- return unlikely(swp_type(entry) == SWP_MIGRATION_READ);
- }
- static inline int is_readable_exclusive_migration_entry(swp_entry_t entry)
- {
- return unlikely(swp_type(entry) == SWP_MIGRATION_READ_EXCLUSIVE);
- }
- static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
- {
- return swp_entry(SWP_MIGRATION_READ, offset);
- }
- static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset)
- {
- return swp_entry(SWP_MIGRATION_READ_EXCLUSIVE, offset);
- }
- static inline swp_entry_t make_writable_migration_entry(pgoff_t offset)
- {
- return swp_entry(SWP_MIGRATION_WRITE, offset);
- }
- /*
- * Returns whether the host has large enough swap offset field to support
- * carrying over pgtable A/D bits for page migrations. The result is
- * pretty much arch specific.
- */
- static inline bool migration_entry_supports_ad(void)
- {
- #ifdef CONFIG_SWAP
- return swap_migration_ad_supported;
- #else /* CONFIG_SWAP */
- return false;
- #endif /* CONFIG_SWAP */
- }
- static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
- {
- if (migration_entry_supports_ad())
- return swp_entry(swp_type(entry),
- swp_offset(entry) | SWP_MIG_YOUNG);
- return entry;
- }
- static inline bool is_migration_entry_young(swp_entry_t entry)
- {
- if (migration_entry_supports_ad())
- return swp_offset(entry) & SWP_MIG_YOUNG;
- /* Keep the old behavior of aging page after migration */
- return false;
- }
- static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
- {
- if (migration_entry_supports_ad())
- return swp_entry(swp_type(entry),
- swp_offset(entry) | SWP_MIG_DIRTY);
- return entry;
- }
- static inline bool is_migration_entry_dirty(swp_entry_t entry)
- {
- if (migration_entry_supports_ad())
- return swp_offset(entry) & SWP_MIG_DIRTY;
- /* Keep the old behavior of clean page after migration */
- return false;
- }
- extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
- spinlock_t *ptl);
- extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
- unsigned long address);
- #ifdef CONFIG_HUGETLB_PAGE
- extern void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl);
- extern void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte);
- #endif /* CONFIG_HUGETLB_PAGE */
- #else /* CONFIG_MIGRATION */
- static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
- {
- return swp_entry(0, 0);
- }
- static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset)
- {
- return swp_entry(0, 0);
- }
- static inline swp_entry_t make_writable_migration_entry(pgoff_t offset)
- {
- return swp_entry(0, 0);
- }
- static inline int is_migration_entry(swp_entry_t swp)
- {
- return 0;
- }
- static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
- spinlock_t *ptl) { }
- static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
- unsigned long address) { }
- #ifdef CONFIG_HUGETLB_PAGE
- static inline void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl) { }
- static inline void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) { }
- #endif /* CONFIG_HUGETLB_PAGE */
- static inline int is_writable_migration_entry(swp_entry_t entry)
- {
- return 0;
- }
- static inline int is_readable_migration_entry(swp_entry_t entry)
- {
- return 0;
- }
- static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
- {
- return entry;
- }
- static inline bool is_migration_entry_young(swp_entry_t entry)
- {
- return false;
- }
- static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
- {
- return entry;
- }
- static inline bool is_migration_entry_dirty(swp_entry_t entry)
- {
- return false;
- }
- #endif /* CONFIG_MIGRATION */
- typedef unsigned long pte_marker;
- #define PTE_MARKER_UFFD_WP BIT(0)
- #define PTE_MARKER_MASK (PTE_MARKER_UFFD_WP)
- #ifdef CONFIG_PTE_MARKER
- static inline swp_entry_t make_pte_marker_entry(pte_marker marker)
- {
- return swp_entry(SWP_PTE_MARKER, marker);
- }
- static inline bool is_pte_marker_entry(swp_entry_t entry)
- {
- return swp_type(entry) == SWP_PTE_MARKER;
- }
- static inline pte_marker pte_marker_get(swp_entry_t entry)
- {
- return swp_offset(entry) & PTE_MARKER_MASK;
- }
- static inline bool is_pte_marker(pte_t pte)
- {
- return is_swap_pte(pte) && is_pte_marker_entry(pte_to_swp_entry(pte));
- }
- #else /* CONFIG_PTE_MARKER */
- static inline swp_entry_t make_pte_marker_entry(pte_marker marker)
- {
- /* This should never be called if !CONFIG_PTE_MARKER */
- WARN_ON_ONCE(1);
- return swp_entry(0, 0);
- }
- static inline bool is_pte_marker_entry(swp_entry_t entry)
- {
- return false;
- }
- static inline pte_marker pte_marker_get(swp_entry_t entry)
- {
- return 0;
- }
- static inline bool is_pte_marker(pte_t pte)
- {
- return false;
- }
- #endif /* CONFIG_PTE_MARKER */
- static inline pte_t make_pte_marker(pte_marker marker)
- {
- return swp_entry_to_pte(make_pte_marker_entry(marker));
- }
- /*
- * This is a special version to check pte_none() just to cover the case when
- * the pte is a pte marker. It existed because in many cases the pte marker
- * should be seen as a none pte; it's just that we have stored some information
- * onto the none pte so it becomes not-none any more.
- *
- * It should be used when the pte is file-backed, ram-based and backing
- * userspace pages, like shmem. It is not needed upon pgtables that do not
- * support pte markers at all. For example, it's not needed on anonymous
- * memory, kernel-only memory (including when the system is during-boot),
- * non-ram based generic file-system. It's fine to be used even there, but the
- * extra pte marker check will be pure overhead.
- *
- * For systems configured with !CONFIG_PTE_MARKER this will be automatically
- * optimized to pte_none().
- */
- static inline int pte_none_mostly(pte_t pte)
- {
- return pte_none(pte) || is_pte_marker(pte);
- }
- static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
- {
- struct page *p = pfn_to_page(swp_offset_pfn(entry));
- /*
- * Any use of migration entries may only occur while the
- * corresponding page is locked
- */
- BUG_ON(is_migration_entry(entry) && !PageLocked(p));
- return p;
- }
- /*
- * A pfn swap entry is a special type of swap entry that always has a pfn stored
- * in the swap offset. They are used to represent unaddressable device memory
- * and to restrict access to a page undergoing migration.
- */
- static inline bool is_pfn_swap_entry(swp_entry_t entry)
- {
- /* Make sure the swp offset can always store the needed fields */
- BUILD_BUG_ON(SWP_TYPE_SHIFT < SWP_PFN_BITS);
- return is_migration_entry(entry) || is_device_private_entry(entry) ||
- is_device_exclusive_entry(entry);
- }
- struct page_vma_mapped_walk;
- #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
- extern int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
- struct page *page);
- extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
- struct page *new);
- extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);
- static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
- {
- swp_entry_t arch_entry;
- if (pmd_swp_soft_dirty(pmd))
- pmd = pmd_swp_clear_soft_dirty(pmd);
- if (pmd_swp_uffd_wp(pmd))
- pmd = pmd_swp_clear_uffd_wp(pmd);
- arch_entry = __pmd_to_swp_entry(pmd);
- return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
- }
- static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
- {
- swp_entry_t arch_entry;
- arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
- return __swp_entry_to_pmd(arch_entry);
- }
- static inline int is_pmd_migration_entry(pmd_t pmd)
- {
- return is_swap_pmd(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
- }
- #else /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
- static inline int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
- struct page *page)
- {
- BUILD_BUG();
- }
- static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
- struct page *new)
- {
- BUILD_BUG();
- }
- static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
- static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
- {
- return swp_entry(0, 0);
- }
- static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
- {
- return __pmd(0);
- }
- static inline int is_pmd_migration_entry(pmd_t pmd)
- {
- return 0;
- }
- #endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
- #ifdef CONFIG_MEMORY_FAILURE
- extern atomic_long_t num_poisoned_pages __read_mostly;
- /*
- * Support for hardware poisoned pages
- */
- static inline swp_entry_t make_hwpoison_entry(struct page *page)
- {
- BUG_ON(!PageLocked(page));
- return swp_entry(SWP_HWPOISON, page_to_pfn(page));
- }
- static inline int is_hwpoison_entry(swp_entry_t entry)
- {
- return swp_type(entry) == SWP_HWPOISON;
- }
- static inline void num_poisoned_pages_inc(void)
- {
- atomic_long_inc(&num_poisoned_pages);
- }
- static inline void num_poisoned_pages_sub(long i)
- {
- atomic_long_sub(i, &num_poisoned_pages);
- }
- #else /* CONFIG_MEMORY_FAILURE */
- static inline swp_entry_t make_hwpoison_entry(struct page *page)
- {
- return swp_entry(0, 0);
- }
- static inline int is_hwpoison_entry(swp_entry_t swp)
- {
- return 0;
- }
- static inline void num_poisoned_pages_inc(void)
- {
- }
- static inline void num_poisoned_pages_sub(long i)
- {
- }
- #endif /* CONFIG_MEMORY_FAILURE */
- static inline int non_swap_entry(swp_entry_t entry)
- {
- return swp_type(entry) >= MAX_SWAPFILES;
- }
- #endif /* CONFIG_MMU */
- #endif /* _LINUX_SWAPOPS_H */
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