365 lines
9.6 KiB
C
365 lines
9.6 KiB
C
/* 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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#ifdef CONFIG_SWAP
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#include <linux/swapfile.h>
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#endif /* CONFIG_SWAP */
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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 six
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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 one bit: 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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/*
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* Definitions only for PFN swap entries (see leafeant_has_pfn()). To
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* store PFN, we only need SWP_PFN_BITS bits. Each of the pfn swap entries
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* can use the extra bits to store other information besides PFN.
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*/
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#ifdef MAX_PHYSMEM_BITS
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#define SWP_PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT)
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#else /* MAX_PHYSMEM_BITS */
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#define SWP_PFN_BITS min_t(int, \
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sizeof(phys_addr_t) * 8 - PAGE_SHIFT, \
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SWP_TYPE_SHIFT)
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#endif /* MAX_PHYSMEM_BITS */
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#define SWP_PFN_MASK (BIT(SWP_PFN_BITS) - 1)
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/**
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* Migration swap entry specific bitfield definitions. Layout:
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*
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* |----------+--------------------|
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* | swp_type | swp_offset |
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* |----------+--------+-+-+-------|
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* | | resv |D|A| PFN |
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* |----------+--------+-+-+-------|
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*
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* @SWP_MIG_YOUNG_BIT: Whether the page used to have young bit set (bit A)
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* @SWP_MIG_DIRTY_BIT: Whether the page used to have dirty bit set (bit D)
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*
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* Note: A/D bits will be stored in migration entries iff there're enough
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* free bits in arch specific swp offset. By default we'll ignore A/D bits
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* when migrating a page. Please refer to migration_entry_supports_ad()
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* for more information. If there're more bits besides PFN and A/D bits,
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* they should be reserved and always be zeros.
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*/
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#define SWP_MIG_YOUNG_BIT (SWP_PFN_BITS)
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#define SWP_MIG_DIRTY_BIT (SWP_PFN_BITS + 1)
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#define SWP_MIG_TOTAL_BITS (SWP_PFN_BITS + 2)
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#define SWP_MIG_YOUNG BIT(SWP_MIG_YOUNG_BIT)
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#define SWP_MIG_DIRTY BIT(SWP_MIG_DIRTY_BIT)
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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_exclusive(pte))
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pte = pte_swp_clear_exclusive(pte);
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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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/*
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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_readable_device_private_entry(pgoff_t offset)
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{
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return swp_entry(SWP_DEVICE_READ, offset);
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}
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static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset)
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{
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return swp_entry(SWP_DEVICE_WRITE, offset);
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}
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static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
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{
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return swp_entry(SWP_DEVICE_EXCLUSIVE, offset);
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}
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#else /* CONFIG_DEVICE_PRIVATE */
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static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
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{
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return swp_entry(0, 0);
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}
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static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset)
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{
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return swp_entry(0, 0);
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}
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static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
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{
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return swp_entry(0, 0);
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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_readable_migration_entry(pgoff_t offset)
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{
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return swp_entry(SWP_MIGRATION_READ, offset);
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}
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static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset)
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{
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return swp_entry(SWP_MIGRATION_READ_EXCLUSIVE, offset);
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}
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static inline swp_entry_t make_writable_migration_entry(pgoff_t offset)
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{
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return swp_entry(SWP_MIGRATION_WRITE, offset);
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}
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/*
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* Returns whether the host has large enough swap offset field to support
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* carrying over pgtable A/D bits for page migrations. The result is
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* pretty much arch specific.
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*/
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static inline bool migration_entry_supports_ad(void)
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{
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#ifdef CONFIG_SWAP
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return swap_migration_ad_supported;
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#else /* CONFIG_SWAP */
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return false;
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#endif /* CONFIG_SWAP */
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}
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static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
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{
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if (migration_entry_supports_ad())
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return swp_entry(swp_type(entry),
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swp_offset(entry) | SWP_MIG_YOUNG);
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return entry;
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}
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static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
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{
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if (migration_entry_supports_ad())
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return swp_entry(swp_type(entry),
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swp_offset(entry) | SWP_MIG_DIRTY);
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return entry;
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}
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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, unsigned long addr, pte_t *pte);
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#else /* CONFIG_MIGRATION */
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static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
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{
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return swp_entry(0, 0);
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}
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static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset)
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{
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return swp_entry(0, 0);
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}
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static inline swp_entry_t make_writable_migration_entry(pgoff_t offset)
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{
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return swp_entry(0, 0);
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}
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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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unsigned long addr, pte_t *pte) { }
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static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
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{
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return entry;
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}
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static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
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{
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return entry;
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}
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#endif /* CONFIG_MIGRATION */
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#ifdef CONFIG_MEMORY_FAILURE
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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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#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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#endif
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typedef unsigned long pte_marker;
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#define PTE_MARKER_UFFD_WP BIT(0)
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/*
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* "Poisoned" here is meant in the very general sense of "future accesses are
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* invalid", instead of referring very specifically to hardware memory errors.
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* This marker is meant to represent any of various different causes of this.
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*
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* Note that, when encountered by the faulting logic, PTEs with this marker will
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* result in VM_FAULT_HWPOISON and thus regardless trigger hardware memory error
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* logic.
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*/
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#define PTE_MARKER_POISONED BIT(1)
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/*
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* Indicates that, on fault, this PTE will case a SIGSEGV signal to be
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* sent. This means guard markers behave in effect as if the region were mapped
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* PROT_NONE, rather than if they were a memory hole or equivalent.
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*/
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#define PTE_MARKER_GUARD BIT(2)
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#define PTE_MARKER_MASK (BIT(3) - 1)
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static inline swp_entry_t make_pte_marker_entry(pte_marker marker)
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{
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return swp_entry(SWP_PTE_MARKER, marker);
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}
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static inline pte_t make_pte_marker(pte_marker marker)
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{
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return swp_entry_to_pte(make_pte_marker_entry(marker));
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}
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static inline swp_entry_t make_poisoned_swp_entry(void)
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{
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return make_pte_marker_entry(PTE_MARKER_POISONED);
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}
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static inline swp_entry_t make_guard_swp_entry(void)
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{
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return make_pte_marker_entry(PTE_MARKER_GUARD);
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}
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struct page_vma_mapped_walk;
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#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
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extern int 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 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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#else /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
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static inline int 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 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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#endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
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#endif /* CONFIG_MMU */
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#endif /* _LINUX_SWAPOPS_H */
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