/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SWAPOPS_H
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#define _LINUX_SWAPOPS_H
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#include <linux/radix-tree.h>
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#include <linux/bug.h>
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#include <linux/mm_types.h>
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#ifdef CONFIG_MMU
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/*
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* swapcache pages are stored in the swapper_space radix tree. We want to
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* get good packing density in that tree, so the index should be dense in
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* the low-order bits.
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*
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* We arrange the `type' and `offset' fields so that `type' is at the seven
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* high-order bits of the swp_entry_t and `offset' is right-aligned in the
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* remaining bits. Although `type' itself needs only five bits, we allow for
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* shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry().
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*
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* swp_entry_t's are *never* stored anywhere in their arch-dependent format.
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*/
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#define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
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#define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
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/* Clear all flags but only keep swp_entry_t related information */
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static inline pte_t pte_swp_clear_flags(pte_t pte)
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{
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if (pte_swp_soft_dirty(pte))
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pte = pte_swp_clear_soft_dirty(pte);
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if (pte_swp_uffd_wp(pte))
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pte = pte_swp_clear_uffd_wp(pte);
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return pte;
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}
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/*
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* Store a type+offset into a swp_entry_t in an arch-independent format
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*/
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static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
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{
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swp_entry_t ret;
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ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
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return ret;
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}
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/*
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* Extract the `type' field from a swp_entry_t. The swp_entry_t is in
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* arch-independent format
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*/
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static inline unsigned swp_type(swp_entry_t entry)
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{
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return (entry.val >> SWP_TYPE_SHIFT);
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}
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/*
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* Extract the `offset' field from a swp_entry_t. The swp_entry_t is in
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* arch-independent format
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*/
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static inline pgoff_t swp_offset(swp_entry_t entry)
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{
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return entry.val & SWP_OFFSET_MASK;
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}
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/* check whether a pte points to a swap entry */
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static inline int is_swap_pte(pte_t pte)
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{
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return !pte_none(pte) && !pte_present(pte);
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}
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/*
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* Convert the arch-dependent pte representation of a swp_entry_t into an
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* arch-independent swp_entry_t.
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*/
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static inline swp_entry_t pte_to_swp_entry(pte_t pte)
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{
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swp_entry_t arch_entry;
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pte = pte_swp_clear_flags(pte);
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arch_entry = __pte_to_swp_entry(pte);
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return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
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}
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/*
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* Convert the arch-independent representation of a swp_entry_t into the
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* arch-dependent pte representation.
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*/
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static inline pte_t swp_entry_to_pte(swp_entry_t entry)
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{
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swp_entry_t arch_entry;
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arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
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return __swp_entry_to_pte(arch_entry);
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}
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static inline swp_entry_t radix_to_swp_entry(void *arg)
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{
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swp_entry_t entry;
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entry.val = xa_to_value(arg);
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return entry;
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}
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static inline void *swp_to_radix_entry(swp_entry_t entry)
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{
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return xa_mk_value(entry.val);
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}
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#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
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static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
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{
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return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ,
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page_to_pfn(page));
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}
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static inline bool is_device_private_entry(swp_entry_t entry)
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{
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int type = swp_type(entry);
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return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE;
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}
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static inline void make_device_private_entry_read(swp_entry_t *entry)
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{
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*entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry));
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}
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static inline bool is_write_device_private_entry(swp_entry_t entry)
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{
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return unlikely(swp_type(entry) == SWP_DEVICE_WRITE);
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}
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static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
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{
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return swp_offset(entry);
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}
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static inline struct page *device_private_entry_to_page(swp_entry_t entry)
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{
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return pfn_to_page(swp_offset(entry));
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}
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#else /* CONFIG_DEVICE_PRIVATE */
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static inline swp_entry_t make_device_private_entry(struct page *page, bool write)
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{
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return swp_entry(0, 0);
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}
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static inline void make_device_private_entry_read(swp_entry_t *entry)
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{
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}
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static inline bool is_device_private_entry(swp_entry_t entry)
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{
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return false;
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}
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static inline bool is_write_device_private_entry(swp_entry_t entry)
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{
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return false;
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}
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static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry)
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{
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return 0;
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}
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static inline struct page *device_private_entry_to_page(swp_entry_t entry)
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{
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return NULL;
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}
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#endif /* CONFIG_DEVICE_PRIVATE */
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#ifdef CONFIG_MIGRATION
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static inline swp_entry_t make_migration_entry(struct page *page, int write)
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{
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BUG_ON(!PageLocked(compound_head(page)));
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return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ,
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page_to_pfn(page));
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}
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static inline int is_migration_entry(swp_entry_t entry)
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{
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return unlikely(swp_type(entry) == SWP_MIGRATION_READ ||
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swp_type(entry) == SWP_MIGRATION_WRITE);
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}
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static inline int is_write_migration_entry(swp_entry_t entry)
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{
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return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE);
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}
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static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
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{
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return swp_offset(entry);
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}
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static inline struct page *migration_entry_to_page(swp_entry_t entry)
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{
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struct page *p = pfn_to_page(swp_offset(entry));
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/*
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* Any use of migration entries may only occur while the
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* corresponding page is locked
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*/
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BUG_ON(!PageLocked(compound_head(p)));
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return p;
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}
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static inline void make_migration_entry_read(swp_entry_t *entry)
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{
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*entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry));
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}
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extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
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spinlock_t *ptl);
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extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
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unsigned long address);
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extern void migration_entry_wait_huge(struct vm_area_struct *vma,
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struct mm_struct *mm, pte_t *pte);
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#else
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#define make_migration_entry(page, write) swp_entry(0, 0)
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static inline int is_migration_entry(swp_entry_t swp)
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{
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return 0;
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}
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static inline unsigned long migration_entry_to_pfn(swp_entry_t entry)
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{
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return 0;
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}
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static inline struct page *migration_entry_to_page(swp_entry_t entry)
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{
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return NULL;
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}
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static inline void make_migration_entry_read(swp_entry_t *entryp) { }
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static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
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spinlock_t *ptl) { }
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static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
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unsigned long address) { }
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static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
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struct mm_struct *mm, pte_t *pte) { }
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static inline int is_write_migration_entry(swp_entry_t entry)
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{
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return 0;
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}
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#endif
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struct page_vma_mapped_walk;
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#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
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extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
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struct page *page);
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extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
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struct page *new);
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extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);
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static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
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{
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swp_entry_t arch_entry;
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if (pmd_swp_soft_dirty(pmd))
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pmd = pmd_swp_clear_soft_dirty(pmd);
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if (pmd_swp_uffd_wp(pmd))
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pmd = pmd_swp_clear_uffd_wp(pmd);
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arch_entry = __pmd_to_swp_entry(pmd);
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return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry));
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}
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static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
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{
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swp_entry_t arch_entry;
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arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
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return __swp_entry_to_pmd(arch_entry);
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}
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static inline int is_pmd_migration_entry(pmd_t pmd)
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{
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return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
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}
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#else
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static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
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struct page *page)
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{
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BUILD_BUG();
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}
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static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
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struct page *new)
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{
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BUILD_BUG();
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}
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static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
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static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
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{
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return swp_entry(0, 0);
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}
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static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
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{
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return __pmd(0);
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}
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static inline int is_pmd_migration_entry(pmd_t pmd)
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{
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return 0;
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}
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#endif
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#ifdef CONFIG_MEMORY_FAILURE
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extern atomic_long_t num_poisoned_pages __read_mostly;
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/*
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* Support for hardware poisoned pages
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*/
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static inline swp_entry_t make_hwpoison_entry(struct page *page)
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{
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BUG_ON(!PageLocked(page));
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return swp_entry(SWP_HWPOISON, page_to_pfn(page));
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}
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static inline int is_hwpoison_entry(swp_entry_t entry)
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{
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return swp_type(entry) == SWP_HWPOISON;
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}
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static inline void num_poisoned_pages_inc(void)
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{
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atomic_long_inc(&num_poisoned_pages);
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}
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static inline void num_poisoned_pages_dec(void)
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{
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atomic_long_dec(&num_poisoned_pages);
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}
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#else
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static inline swp_entry_t make_hwpoison_entry(struct page *page)
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{
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return swp_entry(0, 0);
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}
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static inline int is_hwpoison_entry(swp_entry_t swp)
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{
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return 0;
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}
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static inline void num_poisoned_pages_inc(void)
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{
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}
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#endif
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#if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \
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defined(CONFIG_DEVICE_PRIVATE)
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static inline int non_swap_entry(swp_entry_t entry)
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{
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return swp_type(entry) >= MAX_SWAPFILES;
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}
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#else
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static inline int non_swap_entry(swp_entry_t entry)
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{
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return 0;
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}
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#endif
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#endif /* CONFIG_MMU */
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#endif /* _LINUX_SWAPOPS_H */
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