/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Macros for manipulating and testing page->flags
 */

#ifndef PAGE_FLAGS_H
#define PAGE_FLAGS_H

#include <linux/types.h>
#include <linux/bug.h>
#include <linux/mmdebug.h>
#ifndef __GENERATING_BOUNDS_H
#include <linux/mm_types.h>
#include <generated/bounds.h>
#endif /* !__GENERATING_BOUNDS_H */

/*
 * Various page->flags bits:
 *
 * PG_reserved is set for special pages. The "struct page" of such a page
 * should in general not be touched (e.g. set dirty) except by its owner.
 * Pages marked as PG_reserved include:
 * - Pages part of the kernel image (including vDSO) and similar (e.g. BIOS,
 *   initrd, HW tables)
 * - Pages reserved or allocated early during boot (before the page allocator
 *   was initialized). This includes (depending on the architecture) the
 *   initial vmemmap, initial page tables, crashkernel, elfcorehdr, and much
 *   much more. Once (if ever) freed, PG_reserved is cleared and they will
 *   be given to the page allocator.
 * - Pages falling into physical memory gaps - not IORESOURCE_SYSRAM. Trying
 *   to read/write these pages might end badly. Don't touch!
 * - The zero page(s)
 * - Pages not added to the page allocator when onlining a section because
 *   they were excluded via the online_page_callback() or because they are
 *   PG_hwpoison.
 * - Pages allocated in the context of kexec/kdump (loaded kernel image,
 *   control pages, vmcoreinfo)
 * - MMIO/DMA pages. Some architectures don't allow to ioremap pages that are
 *   not marked PG_reserved (as they might be in use by somebody else who does
 *   not respect the caching strategy).
 * - Pages part of an offline section (struct pages of offline sections should
 *   not be trusted as they will be initialized when first onlined).
 * - MCA pages on ia64
 * - Pages holding CPU notes for POWER Firmware Assisted Dump
 * - Device memory (e.g. PMEM, DAX, HMM)
 * Some PG_reserved pages will be excluded from the hibernation image.
 * PG_reserved does in general not hinder anybody from dumping or swapping
 * and is no longer required for remap_pfn_range(). ioremap might require it.
 * Consequently, PG_reserved for a page mapped into user space can indicate
 * the zero page, the vDSO, MMIO pages or device memory.
 *
 * The PG_private bitflag is set on pagecache pages if they contain filesystem
 * specific data (which is normally at page->private). It can be used by
 * private allocations for its own usage.
 *
 * During initiation of disk I/O, PG_locked is set. This bit is set before I/O
 * and cleared when writeback _starts_ or when read _completes_. PG_writeback
 * is set before writeback starts and cleared when it finishes.
 *
 * PG_locked also pins a page in pagecache, and blocks truncation of the file
 * while it is held.
 *
 * page_waitqueue(page) is a wait queue of all tasks waiting for the page
 * to become unlocked.
 *
 * PG_swapbacked is set when a page uses swap as a backing storage.  This are
 * usually PageAnon or shmem pages but please note that even anonymous pages
 * might lose their PG_swapbacked flag when they simply can be dropped (e.g. as
 * a result of MADV_FREE).
 *
 * PG_referenced, PG_reclaim are used for page reclaim for anonymous and
 * file-backed pagecache (see mm/vmscan.c).
 *
 * PG_error is set to indicate that an I/O error occurred on this page.
 *
 * PG_arch_1 is an architecture specific page state bit.  The generic code
 * guarantees that this bit is cleared for a page when it first is entered into
 * the page cache.
 *
 * PG_hwpoison indicates that a page got corrupted in hardware and contains
 * data with incorrect ECC bits that triggered a machine check. Accessing is
 * not safe since it may cause another machine check. Don't touch!
 */

/*
 * Don't use the pageflags directly.  Use the PageFoo macros.
 *
 * The page flags field is split into two parts, the main flags area
 * which extends from the low bits upwards, and the fields area which
 * extends from the high bits downwards.
 *
 *  | FIELD | ... | FLAGS |
 *  N-1           ^       0
 *               (NR_PAGEFLAGS)
 *
 * The fields area is reserved for fields mapping zone, node (for NUMA) and
 * SPARSEMEM section (for variants of SPARSEMEM that require section ids like
 * SPARSEMEM_EXTREME with !SPARSEMEM_VMEMMAP).
 */
enum pageflags {
        PG_locked,              /* Page is locked. Don't touch. */
        PG_referenced,
        PG_uptodate,
        PG_dirty,
        PG_lru,
        PG_active,
        PG_workingset,
        PG_waiters,             /* Page has waiters, check its waitqueue. Must be bit #7 and in the same byte as "PG_locked" */
        PG_error,
        PG_slab,
        PG_owner_priv_1,        /* Owner use. If pagecache, fs may use*/
        PG_arch_1,
        PG_reserved,
        PG_private,             /* If pagecache, has fs-private data */
        PG_private_2,           /* If pagecache, has fs aux data */
        PG_writeback,           /* Page is under writeback */
        PG_head,                /* A head page */
        PG_mappedtodisk,        /* Has blocks allocated on-disk */
        PG_reclaim,             /* To be reclaimed asap */
        PG_swapbacked,          /* Page is backed by RAM/swap */
        PG_unevictable,         /* Page is "unevictable"  */
#ifdef CONFIG_MMU
        PG_mlocked,             /* Page is vma mlocked */
#endif
#ifdef CONFIG_ARCH_USES_PG_UNCACHED
        PG_uncached,            /* Page has been mapped as uncached */
#endif
#ifdef CONFIG_MEMORY_FAILURE
        PG_hwpoison,            /* hardware poisoned page. Don't touch */
#endif
#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
        PG_young,
        PG_idle,
#endif
#ifdef CONFIG_64BIT
        PG_arch_2,
#endif
#ifdef CONFIG_KASAN_HW_TAGS
        PG_skip_kasan_poison,
#endif
        __NR_PAGEFLAGS,

        PG_readahead = PG_reclaim,

        /*
         * Depending on the way an anonymous folio can be mapped into a page
         * table (e.g., single PMD/PUD/CONT of the head page vs. PTE-mapped
         * THP), PG_anon_exclusive may be set only for the head page or for
         * tail pages of an anonymous folio. For now, we only expect it to be
         * set on tail pages for PTE-mapped THP.
         */
        PG_anon_exclusive = PG_mappedtodisk,

        /* Filesystems */
        PG_checked = PG_owner_priv_1,

        /* SwapBacked */
        PG_swapcache = PG_owner_priv_1, /* Swap page: swp_entry_t in private */

        /* Two page bits are conscripted by FS-Cache to maintain local caching
         * state.  These bits are set on pages belonging to the netfs's inodes
         * when those inodes are being locally cached.
         */
        PG_fscache = PG_private_2,      /* page backed by cache */

        /* XEN */
        /* Pinned in Xen as a read-only pagetable page. */
        PG_pinned = PG_owner_priv_1,
        /* Pinned as part of domain save (see xen_mm_pin_all()). */
        PG_savepinned = PG_dirty,
        /* Has a grant mapping of another (foreign) domain's page. */
        PG_foreign = PG_owner_priv_1,
        /* Remapped by swiotlb-xen. */
        PG_xen_remapped = PG_owner_priv_1,

        /* SLOB */
        PG_slob_free = PG_private,

        /* Compound pages. Stored in first tail page's flags */
        PG_double_map = PG_workingset,

#ifdef CONFIG_MEMORY_FAILURE
        /*
         * Compound pages. Stored in first tail page's flags.
         * Indicates that at least one subpage is hwpoisoned in the
         * THP.
         */
        PG_has_hwpoisoned = PG_error,
#endif

        /* non-lru isolated movable page */
        PG_isolated = PG_reclaim,

        /* Only valid for buddy pages. Used to track pages that are reported */
        PG_reported = PG_uptodate,
};

#define PAGEFLAGS_MASK          ((1UL << NR_PAGEFLAGS) - 1)

#ifndef __GENERATING_BOUNDS_H

#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
DECLARE_STATIC_KEY_MAYBE(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
                         hugetlb_optimize_vmemmap_key);

static __always_inline bool hugetlb_optimize_vmemmap_enabled(void)
{
        return static_branch_maybe(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON,
                                   &hugetlb_optimize_vmemmap_key);
}

/*
 * If the feature of optimizing vmemmap pages associated with each HugeTLB
 * page is enabled, the head vmemmap page frame is reused and all of the tail
 * vmemmap addresses map to the head vmemmap page frame (furture details can
 * refer to the figure at the head of the mm/hugetlb_vmemmap.c).  In other
 * words, there are more than one page struct with PG_head associated with each
 * HugeTLB page.  We __know__ that there is only one head page struct, the tail
 * page structs with PG_head are fake head page structs.  We need an approach
 * to distinguish between those two different types of page structs so that
 * compound_head() can return the real head page struct when the parameter is
 * the tail page struct but with PG_head.
 *
 * The page_fixed_fake_head() returns the real head page struct if the @page is
 * fake page head, otherwise, returns @page which can either be a true page
 * head or tail.
 */
static __always_inline const struct page *page_fixed_fake_head(const struct page *page)
{
        if (!hugetlb_optimize_vmemmap_enabled())
                return page;

        /*
         * Only addresses aligned with PAGE_SIZE of struct page may be fake head
         * struct page. The alignment check aims to avoid access the fields (
         * e.g. compound_head) of the @page[1]. It can avoid touch a (possibly)
         * cold cacheline in some cases.
         */
        if (IS_ALIGNED((unsigned long)page, PAGE_SIZE) &&
            test_bit(PG_head, &page->flags)) {
                /*
                 * We can safely access the field of the @page[1] with PG_head
                 * because the @page is a compound page composed with at least
                 * two contiguous pages.
                 */
                unsigned long head = READ_ONCE(page[1].compound_head);

                if (likely(head & 1))
                        return (const struct page *)(head - 1);
        }
        return page;
}
#else
static inline const struct page *page_fixed_fake_head(const struct page *page)
{
        return page;
}

static inline bool hugetlb_optimize_vmemmap_enabled(void)
{
        return false;
}
#endif

static __always_inline int page_is_fake_head(struct page *page)
{
        return page_fixed_fake_head(page) != page;
}

static inline unsigned long _compound_head(const struct page *page)
{
        unsigned long head = READ_ONCE(page->compound_head);

        if (unlikely(head & 1))
                return head - 1;
        return (unsigned long)page_fixed_fake_head(page);
}

#define compound_head(page)     ((typeof(page))_compound_head(page))

/**
 * page_folio - Converts from page to folio.
 * @p: The page.
 *
 * Every page is part of a folio.  This function cannot be called on a
 * NULL pointer.
 *
 * Context: No reference, nor lock is required on @page.  If the caller
 * does not hold a reference, this call may race with a folio split, so
 * it should re-check the folio still contains this page after gaining
 * a reference on the folio.
 * Return: The folio which contains this page.
 */
#define page_folio(p)           (_Generic((p),                          \
        const struct page *:    (const struct folio *)_compound_head(p), \
        struct page *:          (struct folio *)_compound_head(p)))

/**
 * folio_page - Return a page from a folio.
 * @folio: The folio.
 * @n: The page number to return.
 *
 * @n is relative to the start of the folio.  This function does not
 * check that the page number lies within @folio; the caller is presumed
 * to have a reference to the page.
 */
#define folio_page(folio, n)    nth_page(&(folio)->page, n)

static __always_inline int PageTail(struct page *page)
{
        return READ_ONCE(page->compound_head) & 1 || page_is_fake_head(page);
}

static __always_inline int PageCompound(struct page *page)
{
        return test_bit(PG_head, &page->flags) ||
               READ_ONCE(page->compound_head) & 1;
}

#define PAGE_POISON_PATTERN     -1l
static inline int PagePoisoned(const struct page *page)
{
        return READ_ONCE(page->flags) == PAGE_POISON_PATTERN;
}

#ifdef CONFIG_DEBUG_VM
void page_init_poison(struct page *page, size_t size);
#else
static inline void page_init_poison(struct page *page, size_t size)
{
}
#endif

static unsigned long *folio_flags(struct folio *folio, unsigned n)
{
        struct page *page = &folio->page;

        VM_BUG_ON_PGFLAGS(PageTail(page), page);
        VM_BUG_ON_PGFLAGS(n > 0 && !test_bit(PG_head, &page->flags), page);
        return &page[n].flags;
}

/*
 * Page flags policies wrt compound pages
 *
 * PF_POISONED_CHECK
 *     check if this struct page poisoned/uninitialized
 *
 * PF_ANY:
 *     the page flag is relevant for small, head and tail pages.
 *
 * PF_HEAD:
 *     for compound page all operations related to the page flag applied to
 *     head page.
 *
 * PF_ONLY_HEAD:
 *     for compound page, callers only ever operate on the head page.
 *
 * PF_NO_TAIL:
 *     modifications of the page flag must be done on small or head pages,
 *     checks can be done on tail pages too.
 *
 * PF_NO_COMPOUND:
 *     the page flag is not relevant for compound pages.
 *
 * PF_SECOND:
 *     the page flag is stored in the first tail page.
 */
#define PF_POISONED_CHECK(page) ({                                      \
                VM_BUG_ON_PGFLAGS(PagePoisoned(page), page);            \
                page; })
#define PF_ANY(page, enforce)   PF_POISONED_CHECK(page)
#define PF_HEAD(page, enforce)  PF_POISONED_CHECK(compound_head(page))
#define PF_ONLY_HEAD(page, enforce) ({                                  \
                VM_BUG_ON_PGFLAGS(PageTail(page), page);                \
                PF_POISONED_CHECK(page); })
#define PF_NO_TAIL(page, enforce) ({                                    \
                VM_BUG_ON_PGFLAGS(enforce && PageTail(page), page);     \
                PF_POISONED_CHECK(compound_head(page)); })
#define PF_NO_COMPOUND(page, enforce) ({                                \
                VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
                PF_POISONED_CHECK(page); })
#define PF_SECOND(page, enforce) ({                                     \
                VM_BUG_ON_PGFLAGS(!PageHead(page), page);               \
                PF_POISONED_CHECK(&page[1]); })

/* Which page is the flag stored in */
#define FOLIO_PF_ANY            0
#define FOLIO_PF_HEAD           0
#define FOLIO_PF_ONLY_HEAD      0
#define FOLIO_PF_NO_TAIL        0
#define FOLIO_PF_NO_COMPOUND    0
#define FOLIO_PF_SECOND         1

/*
 * Macros to create function definitions for page flags
 */
#define TESTPAGEFLAG(uname, lname, policy)                              \
static __always_inline bool folio_test_##lname(struct folio *folio)     \
{ return test_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }    \
static __always_inline int Page##uname(struct page *page)               \
{ return test_bit(PG_##lname, &policy(page, 0)->flags); }

#define SETPAGEFLAG(uname, lname, policy)                               \
static __always_inline                                                  \
void folio_set_##lname(struct folio *folio)                             \
{ set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }            \
static __always_inline void SetPage##uname(struct page *page)           \
{ set_bit(PG_##lname, &policy(page, 1)->flags); }

#define CLEARPAGEFLAG(uname, lname, policy)                             \
static __always_inline                                                  \
void folio_clear_##lname(struct folio *folio)                           \
{ clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }          \
static __always_inline void ClearPage##uname(struct page *page)         \
{ clear_bit(PG_##lname, &policy(page, 1)->flags); }

#define __SETPAGEFLAG(uname, lname, policy)                             \
static __always_inline                                                  \
void __folio_set_##lname(struct folio *folio)                           \
{ __set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }          \
static __always_inline void __SetPage##uname(struct page *page)         \
{ __set_bit(PG_##lname, &policy(page, 1)->flags); }

#define __CLEARPAGEFLAG(uname, lname, policy)                           \
static __always_inline                                                  \
void __folio_clear_##lname(struct folio *folio)                         \
{ __clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); }        \
static __always_inline void __ClearPage##uname(struct page *page)       \
{ __clear_bit(PG_##lname, &policy(page, 1)->flags); }

#define TESTSETFLAG(uname, lname, policy)                               \
static __always_inline                                                  \
bool folio_test_set_##lname(struct folio *folio)                        \
{ return test_and_set_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline int TestSetPage##uname(struct page *page)        \
{ return test_and_set_bit(PG_##lname, &policy(page, 1)->flags); }

#define TESTCLEARFLAG(uname, lname, policy)                             \
static __always_inline                                                  \
bool folio_test_clear_##lname(struct folio *folio)                      \
{ return test_and_clear_bit(PG_##lname, folio_flags(folio, FOLIO_##policy)); } \
static __always_inline int TestClearPage##uname(struct page *page)      \
{ return test_and_clear_bit(PG_##lname, &policy(page, 1)->flags); }

#define PAGEFLAG(uname, lname, policy)                                  \
        TESTPAGEFLAG(uname, lname, policy)                              \
        SETPAGEFLAG(uname, lname, policy)                               \
        CLEARPAGEFLAG(uname, lname, policy)

#define __PAGEFLAG(uname, lname, policy)                                \
        TESTPAGEFLAG(uname, lname, policy)                              \
        __SETPAGEFLAG(uname, lname, policy)                             \
        __CLEARPAGEFLAG(uname, lname, policy)

#define TESTSCFLAG(uname, lname, policy)                                \
        TESTSETFLAG(uname, lname, policy)                               \
        TESTCLEARFLAG(uname, lname, policy)

#define TESTPAGEFLAG_FALSE(uname, lname)                                \
static inline bool folio_test_##lname(const struct folio *folio) { return false; } \
static inline int Page##uname(const struct page *page) { return 0; }

#define SETPAGEFLAG_NOOP(uname, lname)                                  \
static inline void folio_set_##lname(struct folio *folio) { }           \
static inline void SetPage##uname(struct page *page) {  }

#define CLEARPAGEFLAG_NOOP(uname, lname)                                \
static inline void folio_clear_##lname(struct folio *folio) { }         \
static inline void ClearPage##uname(struct page *page) {  }

#define __CLEARPAGEFLAG_NOOP(uname, lname)                              \
static inline void __folio_clear_##lname(struct folio *folio) { }       \
static inline void __ClearPage##uname(struct page *page) {  }

#define TESTSETFLAG_FALSE(uname, lname)                                 \
static inline bool folio_test_set_##lname(struct folio *folio)          \
{ return 0; }                                                           \
static inline int TestSetPage##uname(struct page *page) { return 0; }

#define TESTCLEARFLAG_FALSE(uname, lname)                               \
static inline bool folio_test_clear_##lname(struct folio *folio)        \
{ return 0; }                                                           \
static inline int TestClearPage##uname(struct page *page) { return 0; }

#define PAGEFLAG_FALSE(uname, lname) TESTPAGEFLAG_FALSE(uname, lname)   \
        SETPAGEFLAG_NOOP(uname, lname) CLEARPAGEFLAG_NOOP(uname, lname)

#define TESTSCFLAG_FALSE(uname, lname)                                  \
        TESTSETFLAG_FALSE(uname, lname) TESTCLEARFLAG_FALSE(uname, lname)

__PAGEFLAG(Locked, locked, PF_NO_TAIL)
PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL)
PAGEFLAG(Referenced, referenced, PF_HEAD)
        TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
        __SETPAGEFLAG(Referenced, referenced, PF_HEAD)
PAGEFLAG(Dirty, dirty, PF_HEAD) TESTSCFLAG(Dirty, dirty, PF_HEAD)
        __CLEARPAGEFLAG(Dirty, dirty, PF_HEAD)
PAGEFLAG(LRU, lru, PF_HEAD) __CLEARPAGEFLAG(LRU, lru, PF_HEAD)
        TESTCLEARFLAG(LRU, lru, PF_HEAD)
PAGEFLAG(Active, active, PF_HEAD) __CLEARPAGEFLAG(Active, active, PF_HEAD)
        TESTCLEARFLAG(Active, active, PF_HEAD)
PAGEFLAG(Workingset, workingset, PF_HEAD)
        TESTCLEARFLAG(Workingset, workingset, PF_HEAD)
__PAGEFLAG(Slab, slab, PF_NO_TAIL)
__PAGEFLAG(SlobFree, slob_free, PF_NO_TAIL)
PAGEFLAG(Checked, checked, PF_NO_COMPOUND)         /* Used by some filesystems */

/* Xen */
PAGEFLAG(Pinned, pinned, PF_NO_COMPOUND)
        TESTSCFLAG(Pinned, pinned, PF_NO_COMPOUND)
PAGEFLAG(SavePinned, savepinned, PF_NO_COMPOUND);
PAGEFLAG(Foreign, foreign, PF_NO_COMPOUND);
PAGEFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)
        TESTCLEARFLAG(XenRemapped, xen_remapped, PF_NO_COMPOUND)

PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
        __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
        __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND)
PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
        __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)
        __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL)

/*
 * Private page markings that may be used by the filesystem that owns the page
 * for its own purposes.
 * - PG_private and PG_private_2 cause release_folio() and co to be invoked
 */
PAGEFLAG(Private, private, PF_ANY)
PAGEFLAG(Private2, private_2, PF_ANY) TESTSCFLAG(Private2, private_2, PF_ANY)
PAGEFLAG(OwnerPriv1, owner_priv_1, PF_ANY)
        TESTCLEARFLAG(OwnerPriv1, owner_priv_1, PF_ANY)

/*
 * Only test-and-set exist for PG_writeback.  The unconditional operators are
 * risky: they bypass page accounting.
 */
TESTPAGEFLAG(Writeback, writeback, PF_NO_TAIL)
        TESTSCFLAG(Writeback, writeback, PF_NO_TAIL)
PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL)

/* PG_readahead is only used for reads; PG_reclaim is only for writes */
PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL)
        TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL)
PAGEFLAG(Readahead, readahead, PF_NO_COMPOUND)
        TESTCLEARFLAG(Readahead, readahead, PF_NO_COMPOUND)

#ifdef CONFIG_HIGHMEM
/*
 * Must use a macro here due to header dependency issues. page_zone() is not
 * available at this point.
 */
#define PageHighMem(__p) is_highmem_idx(page_zonenum(__p))
#else
PAGEFLAG_FALSE(HighMem, highmem)
#endif

#ifdef CONFIG_SWAP
static __always_inline bool folio_test_swapcache(struct folio *folio)
{
        return folio_test_swapbacked(folio) &&
                        test_bit(PG_swapcache, folio_flags(folio, 0));
}

static __always_inline bool PageSwapCache(struct page *page)
{
        return folio_test_swapcache(page_folio(page));
}

SETPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
CLEARPAGEFLAG(SwapCache, swapcache, PF_NO_TAIL)
#else
PAGEFLAG_FALSE(SwapCache, swapcache)
#endif

PAGEFLAG(Unevictable, unevictable, PF_HEAD)
        __CLEARPAGEFLAG(Unevictable, unevictable, PF_HEAD)
        TESTCLEARFLAG(Unevictable, unevictable, PF_HEAD)

#ifdef CONFIG_MMU
PAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
        __CLEARPAGEFLAG(Mlocked, mlocked, PF_NO_TAIL)
        TESTSCFLAG(Mlocked, mlocked, PF_NO_TAIL)
#else
PAGEFLAG_FALSE(Mlocked, mlocked) __CLEARPAGEFLAG_NOOP(Mlocked, mlocked)
        TESTSCFLAG_FALSE(Mlocked, mlocked)
#endif

#ifdef CONFIG_ARCH_USES_PG_UNCACHED
PAGEFLAG(Uncached, uncached, PF_NO_COMPOUND)
#else
PAGEFLAG_FALSE(Uncached, uncached)
#endif

#ifdef CONFIG_MEMORY_FAILURE
PAGEFLAG(HWPoison, hwpoison, PF_ANY)
TESTSCFLAG(HWPoison, hwpoison, PF_ANY)
#define __PG_HWPOISON (1UL << PG_hwpoison)
#define MAGIC_HWPOISON  0x48575053U     /* HWPS */
extern void SetPageHWPoisonTakenOff(struct page *page);
extern void ClearPageHWPoisonTakenOff(struct page *page);
extern bool take_page_off_buddy(struct page *page);
extern bool put_page_back_buddy(struct page *page);
#else
PAGEFLAG_FALSE(HWPoison, hwpoison)
#define __PG_HWPOISON 0
#endif

#if defined(CONFIG_PAGE_IDLE_FLAG) && defined(CONFIG_64BIT)
TESTPAGEFLAG(Young, young, PF_ANY)
SETPAGEFLAG(Young, young, PF_ANY)
TESTCLEARFLAG(Young, young, PF_ANY)
PAGEFLAG(Idle, idle, PF_ANY)
#endif

#ifdef CONFIG_KASAN_HW_TAGS
PAGEFLAG(SkipKASanPoison, skip_kasan_poison, PF_HEAD)
#else
PAGEFLAG_FALSE(SkipKASanPoison, skip_kasan_poison)
#endif

/*
 * PageReported() is used to track reported free pages within the Buddy
 * allocator. We can use the non-atomic version of the test and set
 * operations as both should be shielded with the zone lock to prevent
 * any possible races on the setting or clearing of the bit.
 */
__PAGEFLAG(Reported, reported, PF_NO_COMPOUND)

/*
 * On an anonymous page mapped into a user virtual memory area,
 * page->mapping points to its anon_vma, not to a struct address_space;
 * with the PAGE_MAPPING_ANON bit set to distinguish it.  See rmap.h.
 *
 * On an anonymous page in a VM_MERGEABLE area, if CONFIG_KSM is enabled,
 * the PAGE_MAPPING_MOVABLE bit may be set along with the PAGE_MAPPING_ANON
 * bit; and then page->mapping points, not to an anon_vma, but to a private
 * structure which KSM associates with that merged page.  See ksm.h.
 *
 * PAGE_MAPPING_KSM without PAGE_MAPPING_ANON is used for non-lru movable
 * page and then page->mapping points a struct address_space.
 *
 * Please note that, confusingly, "page_mapping" refers to the inode
 * address_space which maps the page from disk; whereas "page_mapped"
 * refers to user virtual address space into which the page is mapped.
 */
#define PAGE_MAPPING_ANON       0x1
#define PAGE_MAPPING_MOVABLE    0x2
#define PAGE_MAPPING_KSM        (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)
#define PAGE_MAPPING_FLAGS      (PAGE_MAPPING_ANON | PAGE_MAPPING_MOVABLE)

static __always_inline bool folio_mapping_flags(struct folio *folio)
{
        return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) != 0;
}

static __always_inline int PageMappingFlags(struct page *page)
{
        return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) != 0;
}

static __always_inline bool folio_test_anon(struct folio *folio)
{
        return ((unsigned long)folio->mapping & PAGE_MAPPING_ANON) != 0;
}

static __always_inline bool PageAnon(struct page *page)
{
        return folio_test_anon(page_folio(page));
}

static __always_inline int __PageMovable(struct page *page)
{
        return ((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) ==
                                PAGE_MAPPING_MOVABLE;
}

#ifdef CONFIG_KSM
/*
 * A KSM page is one of those write-protected "shared pages" or "merged pages"
 * which KSM maps into multiple mms, wherever identical anonymous page content
 * is found in VM_MERGEABLE vmas.  It's a PageAnon page, pointing not to any
 * anon_vma, but to that page's node of the stable tree.
 */
static __always_inline bool folio_test_ksm(struct folio *folio)
{
        return ((unsigned long)folio->mapping & PAGE_MAPPING_FLAGS) ==
                                PAGE_MAPPING_KSM;
}

static __always_inline bool PageKsm(struct page *page)
{
        return folio_test_ksm(page_folio(page));
}
#else
TESTPAGEFLAG_FALSE(Ksm, ksm)
#endif

u64 stable_page_flags(struct page *page);

/**
 * folio_test_uptodate - Is this folio up to date?
 * @folio: The folio.
 *
 * The uptodate flag is set on a folio when every byte in the folio is
 * at least as new as the corresponding bytes on storage.  Anonymous
 * and CoW folios are always uptodate.  If the folio is not uptodate,
 * some of the bytes in it may be; see the is_partially_uptodate()
 * address_space operation.
 */
static inline bool folio_test_uptodate(struct folio *folio)
{
        bool ret = test_bit(PG_uptodate, folio_flags(folio, 0));
        /*
         * Must ensure that the data we read out of the folio is loaded
         * _after_ we've loaded folio->flags to check the uptodate bit.
         * We can skip the barrier if the folio is not uptodate, because
         * we wouldn't be reading anything from it.
         *
         * See folio_mark_uptodate() for the other side of the story.
         */
        if (ret)
                smp_rmb();

        return ret;
}

static inline int PageUptodate(struct page *page)
{
        return folio_test_uptodate(page_folio(page));
}

static __always_inline void __folio_mark_uptodate(struct folio *folio)
{
        smp_wmb();
        __set_bit(PG_uptodate, folio_flags(folio, 0));
}

static __always_inline void folio_mark_uptodate(struct folio *folio)
{
        /*
         * Memory barrier must be issued before setting the PG_uptodate bit,
         * so that all previous stores issued in order to bring the folio
         * uptodate are actually visible before folio_test_uptodate becomes true.
         */
        smp_wmb();
        set_bit(PG_uptodate, folio_flags(folio, 0));
}

static __always_inline void __SetPageUptodate(struct page *page)
{
        __folio_mark_uptodate((struct folio *)page);
}

static __always_inline void SetPageUptodate(struct page *page)
{
        folio_mark_uptodate((struct folio *)page);
}

CLEARPAGEFLAG(Uptodate, uptodate, PF_NO_TAIL)

bool __folio_start_writeback(struct folio *folio, bool keep_write);
bool set_page_writeback(struct page *page);

#define folio_start_writeback(folio)                    \
        __folio_start_writeback(folio, false)
#define folio_start_writeback_keepwrite(folio)  \
        __folio_start_writeback(folio, true)

static inline void set_page_writeback_keepwrite(struct page *page)
{
        folio_start_writeback_keepwrite(page_folio(page));
}

static inline bool test_set_page_writeback(struct page *page)
{
        return set_page_writeback(page);
}

static __always_inline bool folio_test_head(struct folio *folio)
{
        return test_bit(PG_head, folio_flags(folio, FOLIO_PF_ANY));
}

static __always_inline int PageHead(struct page *page)
{
        PF_POISONED_CHECK(page);
        return test_bit(PG_head, &page->flags) && !page_is_fake_head(page);
}

__SETPAGEFLAG(Head, head, PF_ANY)
__CLEARPAGEFLAG(Head, head, PF_ANY)
CLEARPAGEFLAG(Head, head, PF_ANY)

/**
 * folio_test_large() - Does this folio contain more than one page?
 * @folio: The folio to test.
 *
 * Return: True if the folio is larger than one page.
 */
static inline bool folio_test_large(struct folio *folio)
{
        return folio_test_head(folio);
}

static __always_inline void set_compound_head(struct page *page, struct page *head)
{
        WRITE_ONCE(page->compound_head, (unsigned long)head + 1);
}

static __always_inline void clear_compound_head(struct page *page)
{
        WRITE_ONCE(page->compound_head, 0);
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline void ClearPageCompound(struct page *page)
{
        BUG_ON(!PageHead(page));
        ClearPageHead(page);
}
#endif

#define PG_head_mask ((1UL << PG_head))

#ifdef CONFIG_HUGETLB_PAGE
int PageHuge(struct page *page);
int PageHeadHuge(struct page *page);
static inline bool folio_test_hugetlb(struct folio *folio)
{
        return PageHeadHuge(&folio->page);
}
#else
TESTPAGEFLAG_FALSE(Huge, hugetlb)
TESTPAGEFLAG_FALSE(HeadHuge, headhuge)
#endif

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for
 * normal or transparent huge pages.
 *
 * PageTransHuge() returns true for both transparent huge and
 * hugetlbfs pages, but not normal pages. PageTransHuge() can only be
 * called only in the core VM paths where hugetlbfs pages can't exist.
 */
static inline int PageTransHuge(struct page *page)
{
        VM_BUG_ON_PAGE(PageTail(page), page);
        return PageHead(page);
}

static inline bool folio_test_transhuge(struct folio *folio)
{
        return folio_test_head(folio);
}

/*
 * PageTransCompound returns true for both transparent huge pages
 * and hugetlbfs pages, so it should only be called when it's known
 * that hugetlbfs pages aren't involved.
 */
static inline int PageTransCompound(struct page *page)
{
        return PageCompound(page);
}

/*
 * PageTransTail returns true for both transparent huge pages
 * and hugetlbfs pages, so it should only be called when it's known
 * that hugetlbfs pages aren't involved.
 */
static inline int PageTransTail(struct page *page)
{
        return PageTail(page);
}

/*
 * PageDoubleMap indicates that the compound page is mapped with PTEs as well
 * as PMDs.
 *
 * This is required for optimization of rmap operations for THP: we can postpone
 * per small page mapcount accounting (and its overhead from atomic operations)
 * until the first PMD split.
 *
 * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
 * by one. This reference will go away with last compound_mapcount.
 *
 * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
 */
PAGEFLAG(DoubleMap, double_map, PF_SECOND)
        TESTSCFLAG(DoubleMap, double_map, PF_SECOND)
#else
TESTPAGEFLAG_FALSE(TransHuge, transhuge)
TESTPAGEFLAG_FALSE(TransCompound, transcompound)
TESTPAGEFLAG_FALSE(TransCompoundMap, transcompoundmap)
TESTPAGEFLAG_FALSE(TransTail, transtail)
PAGEFLAG_FALSE(DoubleMap, double_map)
        TESTSCFLAG_FALSE(DoubleMap, double_map)
#endif

#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
/*
 * PageHasHWPoisoned indicates that at least one subpage is hwpoisoned in the
 * compound page.
 *
 * This flag is set by hwpoison handler.  Cleared by THP split or free page.
 */
PAGEFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
        TESTSCFLAG(HasHWPoisoned, has_hwpoisoned, PF_SECOND)
#else
PAGEFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
        TESTSCFLAG_FALSE(HasHWPoisoned, has_hwpoisoned)
#endif

/*
 * Check if a page is currently marked HWPoisoned. Note that this check is
 * best effort only and inherently racy: there is no way to synchronize with
 * failing hardware.
 */
static inline bool is_page_hwpoison(struct page *page)
{
        if (PageHWPoison(page))
                return true;
        return PageHuge(page) && PageHWPoison(compound_head(page));
}

/*
 * For pages that are never mapped to userspace (and aren't PageSlab),
 * page_type may be used.  Because it is initialised to -1, we invert the
 * sense of the bit, so __SetPageFoo *clears* the bit used for PageFoo, and
 * __ClearPageFoo *sets* the bit used for PageFoo.  We reserve a few high and
 * low bits so that an underflow or overflow of page_mapcount() won't be
 * mistaken for a page type value.
 */

#define PAGE_TYPE_BASE  0xf0000000
/* Reserve              0x0000007f to catch underflows of page_mapcount */
#define PAGE_MAPCOUNT_RESERVE   -128
#define PG_buddy        0x00000080
#define PG_offline      0x00000100
#define PG_table        0x00000200
#define PG_guard        0x00000400

#define PageType(page, flag)                                            \
        ((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)

static inline int page_has_type(struct page *page)
{
        return (int)page->page_type < PAGE_MAPCOUNT_RESERVE;
}

#define PAGE_TYPE_OPS(uname, lname)                                     \
static __always_inline int Page##uname(struct page *page)               \
{                                                                       \
        return PageType(page, PG_##lname);                              \
}                                                                       \
static __always_inline void __SetPage##uname(struct page *page)         \
{                                                                       \
        VM_BUG_ON_PAGE(!PageType(page, 0), page);                       \
        page->page_type &= ~PG_##lname;                                 \
}                                                                       \
static __always_inline void __ClearPage##uname(struct page *page)       \
{                                                                       \
        VM_BUG_ON_PAGE(!Page##uname(page), page);                       \
        page->page_type |= PG_##lname;                                  \
}

/*
 * PageBuddy() indicates that the page is free and in the buddy system
 * (see mm/page_alloc.c).
 */
PAGE_TYPE_OPS(Buddy, buddy)

/*
 * PageOffline() indicates that the page is logically offline although the
 * containing section is online. (e.g. inflated in a balloon driver or
 * not onlined when onlining the section).
 * The content of these pages is effectively stale. Such pages should not
 * be touched (read/write/dump/save) except by their owner.
 *
 * If a driver wants to allow to offline unmovable PageOffline() pages without
 * putting them back to the buddy, it can do so via the memory notifier by
 * decrementing the reference count in MEM_GOING_OFFLINE and incrementing the
 * reference count in MEM_CANCEL_OFFLINE. When offlining, the PageOffline()
 * pages (now with a reference count of zero) are treated like free pages,
 * allowing the containing memory block to get offlined. A driver that
 * relies on this feature is aware that re-onlining the memory block will
 * require to re-set the pages PageOffline() and not giving them to the
 * buddy via online_page_callback_t.
 *
 * There are drivers that mark a page PageOffline() and expect there won't be
 * any further access to page content. PFN walkers that read content of random
 * pages should check PageOffline() and synchronize with such drivers using
 * page_offline_freeze()/page_offline_thaw().
 */
PAGE_TYPE_OPS(Offline, offline)

extern void page_offline_freeze(void);

extern void page_offline_thaw(void);
extern void page_offline_begin(void);
extern void page_offline_end(void);

/*
 * Marks pages in use as page tables.
 */
PAGE_TYPE_OPS(Table, table)

/*
 * Marks guardpages used with debug_pagealloc.
 */
PAGE_TYPE_OPS(Guard, guard)

extern bool is_free_buddy_page(struct page *page);

PAGEFLAG(Isolated, isolated, PF_ANY);

static __always_inline int PageAnonExclusive(struct page *page)
{
        VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
        VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
        return test_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
}

static __always_inline void SetPageAnonExclusive(struct page *page)
{
        VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
        VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
        set_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
}

static __always_inline void ClearPageAnonExclusive(struct page *page)
{
        VM_BUG_ON_PGFLAGS(!PageAnon(page) || PageKsm(page), page);
        VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
        clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
}

static __always_inline void __ClearPageAnonExclusive(struct page *page)
{
        VM_BUG_ON_PGFLAGS(!PageAnon(page), page);
        VM_BUG_ON_PGFLAGS(PageHuge(page) && !PageHead(page), page);
        __clear_bit(PG_anon_exclusive, &PF_ANY(page, 1)->flags);
}

#ifdef CONFIG_MMU
#define __PG_MLOCKED            (1UL << PG_mlocked)
#else
#define __PG_MLOCKED            0
#endif

/*
 * Flags checked when a page is freed.  Pages being freed should not have
 * these flags set.  If they are, there is a problem.
 */
#define PAGE_FLAGS_CHECK_AT_FREE                                \
        (1UL << PG_lru          | 1UL << PG_locked      |       \
         1UL << PG_private      | 1UL << PG_private_2   |       \
         1UL << PG_writeback    | 1UL << PG_reserved    |       \
         1UL << PG_slab         | 1UL << PG_active      |       \
         1UL << PG_unevictable  | __PG_MLOCKED)

/*
 * Flags checked when a page is prepped for return by the page allocator.
 * Pages being prepped should not have these flags set.  If they are set,
 * there has been a kernel bug or struct page corruption.
 *
 * __PG_HWPOISON is exceptional because it needs to be kept beyond page's
 * alloc-free cycle to prevent from reusing the page.
 */
#define PAGE_FLAGS_CHECK_AT_PREP        \
        (PAGEFLAGS_MASK & ~__PG_HWPOISON)

#define PAGE_FLAGS_PRIVATE                              \
        (1UL << PG_private | 1UL << PG_private_2)
/**
 * page_has_private - Determine if page has private stuff
 * @page: The page to be checked
 *
 * Determine if a page has private stuff, indicating that release routines
 * should be invoked upon it.
 */
static inline int page_has_private(struct page *page)
{
        return !!(page->flags & PAGE_FLAGS_PRIVATE);
}

static inline bool folio_has_private(struct folio *folio)
{
        return page_has_private(&folio->page);
}

#undef PF_ANY
#undef PF_HEAD
#undef PF_ONLY_HEAD
#undef PF_NO_TAIL
#undef PF_NO_COMPOUND
#undef PF_SECOND
#endif /* !__GENERATING_BOUNDS_H */

#endif  /* PAGE_FLAGS_H */