593 lines
16 KiB
C
593 lines
16 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 is_pfn_swap_entry()). 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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static inline bool is_pfn_swap_entry(swp_entry_t entry);
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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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* This should only be called upon a pfn swap entry to get the PFN stored
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* in the swap entry. Please refers to is_pfn_swap_entry() for definition
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* of pfn swap entry.
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*/
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static inline unsigned long swp_offset_pfn(swp_entry_t entry)
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{
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VM_BUG_ON(!is_pfn_swap_entry(entry));
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return swp_offset(entry) & SWP_PFN_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_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 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 bool is_writable_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 swp_entry_t make_readable_device_exclusive_entry(pgoff_t offset)
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{
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return swp_entry(SWP_DEVICE_EXCLUSIVE_READ, offset);
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}
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static inline swp_entry_t make_writable_device_exclusive_entry(pgoff_t offset)
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{
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return swp_entry(SWP_DEVICE_EXCLUSIVE_WRITE, offset);
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}
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static inline bool is_device_exclusive_entry(swp_entry_t entry)
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{
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return swp_type(entry) == SWP_DEVICE_EXCLUSIVE_READ ||
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swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE;
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}
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static inline bool is_writable_device_exclusive_entry(swp_entry_t entry)
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{
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return unlikely(swp_type(entry) == SWP_DEVICE_EXCLUSIVE_WRITE);
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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 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_writable_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 swp_entry_t make_readable_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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static inline swp_entry_t make_writable_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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static inline bool is_device_exclusive_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_writable_device_exclusive_entry(swp_entry_t entry)
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{
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return false;
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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 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_READ_EXCLUSIVE ||
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swp_type(entry) == SWP_MIGRATION_WRITE);
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}
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static inline int is_writable_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 int is_readable_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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}
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static inline int is_readable_exclusive_migration_entry(swp_entry_t entry)
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{
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return unlikely(swp_type(entry) == SWP_MIGRATION_READ_EXCLUSIVE);
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}
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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 bool is_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_offset(entry) & SWP_MIG_YOUNG;
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/* Keep the old behavior of aging page after migration */
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return false;
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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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static inline bool is_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_offset(entry) & SWP_MIG_DIRTY;
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/* Keep the old behavior of clean page after migration */
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return false;
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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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#ifdef CONFIG_HUGETLB_PAGE
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extern void __migration_entry_wait_huge(struct vm_area_struct *vma,
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pte_t *ptep, spinlock_t *ptl);
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extern void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte);
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#endif /* CONFIG_HUGETLB_PAGE */
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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 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 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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#ifdef CONFIG_HUGETLB_PAGE
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static inline void __migration_entry_wait_huge(struct vm_area_struct *vma,
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pte_t *ptep, spinlock_t *ptl) { }
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static inline void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) { }
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#endif /* CONFIG_HUGETLB_PAGE */
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static inline int is_writable_migration_entry(swp_entry_t entry)
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{
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return 0;
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}
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static inline int is_readable_migration_entry(swp_entry_t entry)
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{
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return 0;
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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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return entry;
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}
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static inline bool is_migration_entry_young(swp_entry_t entry)
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{
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return false;
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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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static inline bool is_migration_entry_dirty(swp_entry_t entry)
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{
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return false;
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}
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#endif /* CONFIG_MIGRATION */
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typedef unsigned long pte_marker;
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#define PTE_MARKER_UFFD_WP BIT(0)
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#define PTE_MARKER_SWAPIN_ERROR BIT(1)
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#define PTE_MARKER_MASK (BIT(2) - 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 bool is_pte_marker_entry(swp_entry_t entry)
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{
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return swp_type(entry) == SWP_PTE_MARKER;
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}
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static inline pte_marker pte_marker_get(swp_entry_t entry)
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{
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return swp_offset(entry) & PTE_MARKER_MASK;
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}
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static inline bool is_pte_marker(pte_t pte)
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{
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return is_swap_pte(pte) && is_pte_marker_entry(pte_to_swp_entry(pte));
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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_swapin_error_entry(void)
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{
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return make_pte_marker_entry(PTE_MARKER_SWAPIN_ERROR);
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}
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static inline int is_swapin_error_entry(swp_entry_t entry)
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{
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return is_pte_marker_entry(entry) &&
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(pte_marker_get(entry) & PTE_MARKER_SWAPIN_ERROR);
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}
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/*
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* This is a special version to check pte_none() just to cover the case when
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* the pte is a pte marker. It existed because in many cases the pte marker
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* should be seen as a none pte; it's just that we have stored some information
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* onto the none pte so it becomes not-none any more.
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*
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* It should be used when the pte is file-backed, ram-based and backing
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* userspace pages, like shmem. It is not needed upon pgtables that do not
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* support pte markers at all. For example, it's not needed on anonymous
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* memory, kernel-only memory (including when the system is during-boot),
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* non-ram based generic file-system. It's fine to be used even there, but the
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* extra pte marker check will be pure overhead.
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*/
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static inline int pte_none_mostly(pte_t pte)
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{
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return pte_none(pte) || is_pte_marker(pte);
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}
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static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
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{
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struct page *p = pfn_to_page(swp_offset_pfn(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(is_migration_entry(entry) && !PageLocked(p));
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return p;
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}
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/*
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* A pfn swap entry is a special type of swap entry that always has a pfn stored
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* in the swap offset. They are used to represent unaddressable device memory
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* and to restrict access to a page undergoing migration.
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*/
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static inline bool is_pfn_swap_entry(swp_entry_t entry)
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{
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/* Make sure the swp offset can always store the needed fields */
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BUILD_BUG_ON(SWP_TYPE_SHIFT < SWP_PFN_BITS);
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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 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 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 is_swap_pmd(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
|
|
}
|
|
#else /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
|
|
static inline int 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 /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
|
|
|
|
#ifdef CONFIG_MEMORY_FAILURE
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
#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;
|
|
}
|
|
#endif
|
|
|
|
static inline int non_swap_entry(swp_entry_t entry)
|
|
{
|
|
return swp_type(entry) >= MAX_SWAPFILES;
|
|
}
|
|
|
|
#endif /* CONFIG_MMU */
|
|
#endif /* _LINUX_SWAPOPS_H */
|