diff options
Diffstat (limited to 'include/linux/swapops.h')
| -rw-r--r-- | include/linux/swapops.h | 321 |
1 files changed, 226 insertions, 95 deletions
diff --git a/include/linux/swapops.h b/include/linux/swapops.h index c5ff7b217ee6..8cfc966eae48 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -1,24 +1,82 @@ +/* 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 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(e) ((sizeof(e.val) * 8) - \ - (MAX_SWAPFILES_SHIFT + RADIX_TREE_EXCEPTIONAL_SHIFT)) -#define SWP_OFFSET_MASK(e) ((1UL << SWP_TYPE_SHIFT(e)) - 1) +#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)) + pte = pte_swp_clear_uffd_wp(pte); + return pte; +} /* * Store a type+offset into a swp_entry_t in an arch-independent format @@ -27,8 +85,7 @@ static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset) { swp_entry_t ret; - ret.val = (type << SWP_TYPE_SHIFT(ret)) | - (offset & SWP_OFFSET_MASK(ret)); + ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK); return ret; } @@ -38,7 +95,7 @@ static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset) */ static inline unsigned swp_type(swp_entry_t entry) { - return (entry.val >> SWP_TYPE_SHIFT(entry)); + return (entry.val >> SWP_TYPE_SHIFT); } /* @@ -47,29 +104,7 @@ static inline unsigned swp_type(swp_entry_t entry) */ static inline pgoff_t swp_offset(swp_entry_t entry) { - return entry.val & SWP_OFFSET_MASK(entry); -} - -#ifdef CONFIG_MMU -/* 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); -} -#endif - -/* - * 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; - - if (pte_swp_soft_dirty(pte)) - pte = pte_swp_clear_soft_dirty(pte); - arch_entry = __pte_to_swp_entry(pte); - return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); + return entry.val & SWP_OFFSET_MASK; } /* @@ -88,84 +123,133 @@ static inline swp_entry_t radix_to_swp_entry(void *arg) { swp_entry_t entry; - entry.val = (unsigned long)arg >> RADIX_TREE_EXCEPTIONAL_SHIFT; + entry.val = xa_to_value(arg); return entry; } static inline void *swp_to_radix_entry(swp_entry_t entry) { - unsigned long value; + 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); +} - value = entry.val << RADIX_TREE_EXCEPTIONAL_SHIFT; - return (void *)(value | RADIX_TREE_EXCEPTIONAL_ENTRY); +static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset) +{ + return swp_entry(SWP_DEVICE_WRITE, offset); +} + +static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset) +{ + return swp_entry(SWP_DEVICE_EXCLUSIVE, offset); } +#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 swp_entry_t make_device_exclusive_entry(pgoff_t offset) +{ + return swp_entry(0, 0); +} + +#endif /* CONFIG_DEVICE_PRIVATE */ + #ifdef CONFIG_MIGRATION -static inline swp_entry_t make_migration_entry(struct page *page, int write) + +static inline swp_entry_t make_readable_migration_entry(pgoff_t offset) { - BUG_ON(!PageLocked(page)); - return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ, - page_to_pfn(page)); + return swp_entry(SWP_MIGRATION_READ, offset); } -static inline int is_migration_entry(swp_entry_t entry) +static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset) { - return unlikely(swp_type(entry) == SWP_MIGRATION_READ || - swp_type(entry) == SWP_MIGRATION_WRITE); + return swp_entry(SWP_MIGRATION_READ_EXCLUSIVE, offset); } -static inline int is_write_migration_entry(swp_entry_t entry) +static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) { - return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); + return swp_entry(SWP_MIGRATION_WRITE, offset); } -static inline struct page *migration_entry_to_page(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) { - 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(!PageLocked(p)); - return p; +#ifdef CONFIG_SWAP + return swap_migration_ad_supported; +#else /* CONFIG_SWAP */ + return false; +#endif /* CONFIG_SWAP */ } -static inline void make_migration_entry_read(swp_entry_t *entry) +static inline swp_entry_t make_migration_entry_young(swp_entry_t entry) { - *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); + 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_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; } -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 +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); +} -#define make_migration_entry(page, write) swp_entry(0, 0) -static inline int is_migration_entry(swp_entry_t swp) +static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset) { - return 0; + return swp_entry(0, 0); } -#define migration_entry_to_page(swp) NULL -static inline void make_migration_entry_read(swp_entry_t *entryp) { } -static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, - spinlock_t *ptl) { } + +static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) +{ + return swp_entry(0, 0); +} + static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, - unsigned long address) { } + 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_write_migration_entry(swp_entry_t entry) + unsigned long addr, pte_t *pte) { } + +static inline swp_entry_t make_migration_entry_young(swp_entry_t entry) { - return 0; + return entry; } -#endif +static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry) +{ + return entry; +} -#ifdef CONFIG_MEMORY_FAILURE +#endif /* CONFIG_MIGRATION */ -extern atomic_long_t num_poisoned_pages __read_mostly; +#ifdef CONFIG_MEMORY_FAILURE /* * Support for hardware poisoned pages @@ -181,53 +265,100 @@ static inline int is_hwpoison_entry(swp_entry_t entry) return swp_type(entry) == SWP_HWPOISON; } -static inline bool test_set_page_hwpoison(struct page *page) +#else + +static inline swp_entry_t make_hwpoison_entry(struct page *page) { - return TestSetPageHWPoison(page); + return swp_entry(0, 0); } -static inline void num_poisoned_pages_inc(void) +static inline int is_hwpoison_entry(swp_entry_t swp) { - atomic_long_inc(&num_poisoned_pages); + return 0; } +#endif -static inline void num_poisoned_pages_dec(void) +typedef unsigned long pte_marker; + +#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 swp_entry_t make_pte_marker_entry(pte_marker marker) { - atomic_long_dec(&num_poisoned_pages); + return swp_entry(SWP_PTE_MARKER, marker); } -#else +static inline pte_t make_pte_marker(pte_marker marker) +{ + return swp_entry_to_pte(make_pte_marker_entry(marker)); +} -static inline swp_entry_t make_hwpoison_entry(struct page *page) +static inline swp_entry_t make_poisoned_swp_entry(void) { - return swp_entry(0, 0); + return make_pte_marker_entry(PTE_MARKER_POISONED); } -static inline int is_hwpoison_entry(swp_entry_t swp) +static inline swp_entry_t make_guard_swp_entry(void) { - return 0; + return make_pte_marker_entry(PTE_MARKER_GUARD); } -static inline bool test_set_page_hwpoison(struct page *page) +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 pmd_t swp_entry_to_pmd(swp_entry_t entry) { - return false; + swp_entry_t arch_entry; + + arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); + return __swp_entry_to_pmd(arch_entry); } -static inline void num_poisoned_pages_inc(void) +#else /* CONFIG_ARCH_ENABLE_THP_MIGRATION */ +static inline int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, + struct page *page) { + BUILD_BUG(); } -#endif -#if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) -static inline int non_swap_entry(swp_entry_t entry) +static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, + struct page *new) { - return swp_type(entry) >= MAX_SWAPFILES; + BUILD_BUG(); } -#else -static inline int non_swap_entry(swp_entry_t entry) + +static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { } + +static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) { - return 0; + return __pmd(0); } -#endif +#endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */ + +#endif /* CONFIG_MMU */ #endif /* _LINUX_SWAPOPS_H */ |