diff options
Diffstat (limited to 'include/linux/swapops.h')
| -rw-r--r-- | include/linux/swapops.h | 348 |
1 files changed, 154 insertions, 194 deletions
diff --git a/include/linux/swapops.h b/include/linux/swapops.h index d356ab4047f7..8cfc966eae48 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -8,24 +8,69 @@ #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 seven + * 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 two bits: see swp_to_radix_entry(). + * 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 leafeant_has_pfn()). 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) + /* 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)) @@ -62,25 +107,6 @@ 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. @@ -117,164 +143,186 @@ 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) +static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset) { - int type = swp_type(entry); - return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE; + return swp_entry(SWP_DEVICE_EXCLUSIVE, offset); } -static inline bool is_writable_device_private_entry(swp_entry_t entry) +#else /* CONFIG_DEVICE_PRIVATE */ +static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset) { - return unlikely(swp_type(entry) == SWP_DEVICE_WRITE); + return swp_entry(0, 0); } -static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset) +static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset) { - return swp_entry(SWP_DEVICE_EXCLUSIVE_READ, offset); + return swp_entry(0, 0); } -static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset) +static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset) { - return swp_entry(SWP_DEVICE_EXCLUSIVE_WRITE, offset); + return swp_entry(0, 0); } -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; -} +#endif /* CONFIG_DEVICE_PRIVATE */ -static inline bool is_writable_device_exclusive_entry(swp_entry_t entry) +#ifdef CONFIG_MIGRATION + +static inline swp_entry_t make_readable_migration_entry(pgoff_t offset) { - return unlikely(swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE); + return swp_entry(SWP_MIGRATION_READ, offset); } -#else /* CONFIG_DEVICE_PRIVATE */ -static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset) + +static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset) { - return swp_entry(0, 0); + return swp_entry(SWP_MIGRATION_READ_EXCLUSIVE, offset); } -static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset) +static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) { - return swp_entry(0, 0); + return swp_entry(SWP_MIGRATION_WRITE, offset); } -static inline bool is_device_private_entry(swp_entry_t entry) +/* + * 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 bool is_writable_device_private_entry(swp_entry_t entry) +static inline swp_entry_t make_migration_entry_young(swp_entry_t entry) { - return false; + if (migration_entry_supports_ad()) + return swp_entry(swp_type(entry), + swp_offset(entry) | SWP_MIG_YOUNG); + return entry; } -static inline swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset) +static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry) { - return swp_entry(0, 0); + if (migration_entry_supports_ad()) + return swp_entry(swp_type(entry), + swp_offset(entry) | SWP_MIG_DIRTY); + return entry; } -static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset) +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, unsigned long addr, pte_t *pte); +#else /* CONFIG_MIGRATION */ +static inline swp_entry_t make_readable_migration_entry(pgoff_t offset) { return swp_entry(0, 0); } -static inline bool is_device_exclusive_entry(swp_entry_t entry) +static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset) { - return false; + return swp_entry(0, 0); } -static inline bool is_writable_device_exclusive_entry(swp_entry_t entry) +static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) { - return false; + return swp_entry(0, 0); } -#endif /* CONFIG_DEVICE_PRIVATE */ -#ifdef CONFIG_MIGRATION -static inline int is_migration_entry(swp_entry_t entry) +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, + unsigned long addr, pte_t *pte) { } + +static inline swp_entry_t make_migration_entry_young(swp_entry_t entry) { - return unlikely(swp_type(entry) == SWP_MIGRATION_READ || - swp_type(entry) == SWP_MIGRATION_WRITE); + return entry; } -static inline int is_writable_migration_entry(swp_entry_t entry) +static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry) { - return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); + return entry; } -static inline swp_entry_t make_readable_migration_entry(pgoff_t offset) +#endif /* CONFIG_MIGRATION */ + +#ifdef CONFIG_MEMORY_FAILURE + +/* + * Support for hardware poisoned pages + */ +static inline swp_entry_t make_hwpoison_entry(struct page *page) { - return swp_entry(SWP_MIGRATION_READ, offset); + BUG_ON(!PageLocked(page)); + return swp_entry(SWP_HWPOISON, page_to_pfn(page)); } -static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) +static inline int is_hwpoison_entry(swp_entry_t entry) { - return swp_entry(SWP_MIGRATION_WRITE, offset); + return swp_type(entry) == SWP_HWPOISON; } -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) +static inline swp_entry_t make_hwpoison_entry(struct page *page) { return swp_entry(0, 0); } -static inline int is_migration_entry(swp_entry_t swp) +static inline int is_hwpoison_entry(swp_entry_t swp) { return 0; } +#endif -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; -} +typedef unsigned long pte_marker; -#endif +#define PTE_MARKER_UFFD_WP BIT(0) +/* + * "Poisoned" here is meant in the very general sense of "future accesses are + * invalid", instead of referring very specifically to hardware memory errors. + * This marker is meant to represent any of various different causes of this. + * + * Note that, when encountered by the faulting logic, PTEs with this marker will + * result in VM_FAULT_HWPOISON and thus regardless trigger hardware memory error + * logic. + */ +#define PTE_MARKER_POISONED BIT(1) +/* + * Indicates that, on fault, this PTE will case a SIGSEGV signal to be + * sent. This means guard markers behave in effect as if the region were mapped + * PROT_NONE, rather than if they were a memory hole or equivalent. + */ +#define PTE_MARKER_GUARD BIT(2) +#define PTE_MARKER_MASK (BIT(3) - 1) -static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry) +static inline swp_entry_t make_pte_marker_entry(pte_marker marker) { - struct page *p = pfn_to_page(swp_offset(entry)); + return swp_entry(SWP_PTE_MARKER, marker); +} - /* - * Any use of migration entries may only occur while the - * corresponding page is locked - */ - BUG_ON(is_migration_entry(entry) && !PageLocked(p)); +static inline pte_t make_pte_marker(pte_marker marker) +{ + return swp_entry_to_pte(make_pte_marker_entry(marker)); +} - return p; +static inline swp_entry_t make_poisoned_swp_entry(void) +{ + return make_pte_marker_entry(PTE_MARKER_POISONED); } -/* - * 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) +static inline swp_entry_t make_guard_swp_entry(void) { - return is_migration_entry(entry) || is_device_private_entry(entry) || - is_device_exclusive_entry(entry); + return make_pte_marker_entry(PTE_MARKER_GUARD); } struct page_vma_mapped_walk; #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION -extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, +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, @@ -282,18 +330,6 @@ extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 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; @@ -302,12 +338,8 @@ static inline pmd_t swp_entry_to_pmd(swp_entry_t 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, +#else /* CONFIG_ARCH_ENABLE_THP_MIGRATION */ +static inline int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, struct page *page) { BUILD_BUG(); @@ -321,84 +353,12 @@ static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 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_ARCH_ENABLE_THP_MIGRATION */ #endif /* CONFIG_MMU */ #endif /* _LINUX_SWAPOPS_H */ |