| /* 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 |
| |
| /* |
| * 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 seven |
| * 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 two bits: 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) |
| |
| /* 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_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; |
| } |
| |
| /* 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); |
| } |
| |
| #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_WRITE); |
| } |
| |
| static inline int is_writable_migration_entry(swp_entry_t entry) |
| { |
| return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); |
| } |
| |
| 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_writable_migration_entry(pgoff_t offset) |
| { |
| return swp_entry(SWP_MIGRATION_WRITE, offset); |
| } |
| |
| 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); |
| extern void migration_entry_wait_huge(struct vm_area_struct *vma, |
| struct mm_struct *mm, pte_t *pte); |
| #else |
| static inline swp_entry_t make_readable_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) { } |
| static inline void migration_entry_wait_huge(struct vm_area_struct *vma, |
| struct mm_struct *mm, pte_t *pte) { } |
| static inline int is_writable_migration_entry(swp_entry_t entry) |
| { |
| return 0; |
| } |
| |
| #endif |
| |
| static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry) |
| { |
| struct page *p = pfn_to_page(swp_offset(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) |
| { |
| 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 void 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 !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd)); |
| } |
| #else |
| static inline void 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 |
| |
| #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 unsigned long hwpoison_entry_to_pfn(swp_entry_t entry) |
| { |
| return swp_offset(entry); |
| } |
| |
| static inline void num_poisoned_pages_inc(void) |
| { |
| atomic_long_inc(&num_poisoned_pages); |
| } |
| |
| static inline void num_poisoned_pages_dec(void) |
| { |
| atomic_long_dec(&num_poisoned_pages); |
| } |
| |
| #else |
| |
| 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) |
| { |
| } |
| #endif |
| |
| #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \ |
| defined(CONFIG_DEVICE_PRIVATE) |
| static inline int non_swap_entry(swp_entry_t entry) |
| { |
| return swp_type(entry) >= MAX_SWAPFILES; |
| } |
| #else |
| static inline int non_swap_entry(swp_entry_t entry) |
| { |
| return 0; |
| } |
| #endif |
| |
| #endif /* CONFIG_MMU */ |
| #endif /* _LINUX_SWAPOPS_H */ |