/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SWAPOPS_H
#define _LINUX_SWAPOPS_H

#include <linux/radix-tree.h>
#include <linux/bug.h>
#include <linux/mm_types.h>

#ifdef CONFIG_MMU

#ifdef CONFIG_SWAP
#include <linux/swapfile.h>
#endif	


#define SWP_TYPE_SHIFT	(BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
#define SWP_OFFSET_MASK	((1UL << SWP_TYPE_SHIFT) - 1)


#ifdef MAX_PHYSMEM_BITS
#define SWP_PFN_BITS		(MAX_PHYSMEM_BITS - PAGE_SHIFT)
#else  
#define SWP_PFN_BITS		min_t(int, \
				      sizeof(phys_addr_t) * 8 - PAGE_SHIFT, \
				      SWP_TYPE_SHIFT)
#endif	
#define SWP_PFN_MASK		(BIT(SWP_PFN_BITS) - 1)


#define SWP_MIG_YOUNG_BIT		(SWP_PFN_BITS)
#define SWP_MIG_DIRTY_BIT		(SWP_PFN_BITS + 1)
#define SWP_MIG_TOTAL_BITS		(SWP_PFN_BITS + 2)

#define SWP_MIG_YOUNG			BIT(SWP_MIG_YOUNG_BIT)
#define SWP_MIG_DIRTY			BIT(SWP_MIG_DIRTY_BIT)


static inline pte_t pte_swp_clear_flags(pte_t pte)
{
	if (pte_swp_exclusive(pte))
		pte = pte_swp_clear_exclusive(pte);
	if (pte_swp_soft_dirty(pte))
		pte = pte_swp_clear_soft_dirty(pte);
	if (pte_swp_uffd_wp(pte))
		pte = pte_swp_clear_uffd_wp(pte);
	return pte;
}


static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset)
{
	swp_entry_t ret;

	ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK);
	return ret;
}


static inline unsigned swp_type(swp_entry_t entry)
{
	return (entry.val >> SWP_TYPE_SHIFT);
}


static inline pgoff_t swp_offset(swp_entry_t entry)
{
	return entry.val & SWP_OFFSET_MASK;
}


static inline pte_t swp_entry_to_pte(swp_entry_t entry)
{
	swp_entry_t arch_entry;

	arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
	return __swp_entry_to_pte(arch_entry);
}

static inline swp_entry_t radix_to_swp_entry(void *arg)
{
	swp_entry_t entry;

	entry.val = xa_to_value(arg);
	return entry;
}

static inline void *swp_to_radix_entry(swp_entry_t entry)
{
	return xa_mk_value(entry.val);
}

#if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
{
	return swp_entry(SWP_DEVICE_READ, offset);
}

static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset)
{
	return swp_entry(SWP_DEVICE_WRITE, offset);
}

static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
{
	return swp_entry(SWP_DEVICE_EXCLUSIVE, offset);
}

#else 
static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset)
{
	return swp_entry(0, 0);
}

static inline swp_entry_t make_writable_device_private_entry(pgoff_t offset)
{
	return swp_entry(0, 0);
}

static inline swp_entry_t make_device_exclusive_entry(pgoff_t offset)
{
	return swp_entry(0, 0);
}

#endif 

#ifdef CONFIG_MIGRATION

static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
{
	return swp_entry(SWP_MIGRATION_READ, offset);
}

static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset)
{
	return swp_entry(SWP_MIGRATION_READ_EXCLUSIVE, offset);
}

static inline swp_entry_t make_writable_migration_entry(pgoff_t offset)
{
	return swp_entry(SWP_MIGRATION_WRITE, offset);
}


static inline bool migration_entry_supports_ad(void)
{
#ifdef CONFIG_SWAP
	return swap_migration_ad_supported;
#else  
	return false;
#endif	
}

static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
{
	if (migration_entry_supports_ad())
		return swp_entry(swp_type(entry),
				 swp_offset(entry) | SWP_MIG_YOUNG);
	return entry;
}

static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
{
	if (migration_entry_supports_ad())
		return swp_entry(swp_type(entry),
				 swp_offset(entry) | SWP_MIG_DIRTY);
	return entry;
}

extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
					unsigned long address);
extern void migration_entry_wait_huge(struct vm_area_struct *vma, unsigned long addr, pte_t *pte);
#else  
static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
{
	return swp_entry(0, 0);
}

static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset)
{
	return swp_entry(0, 0);
}

static inline swp_entry_t make_writable_migration_entry(pgoff_t offset)
{
	return swp_entry(0, 0);
}

static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
					unsigned long address) { }
static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
					     unsigned long addr, pte_t *pte) { }

static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
{
	return entry;
}

static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
{
	return entry;
}

#endif	

#ifdef CONFIG_MEMORY_FAILURE


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

typedef unsigned long pte_marker;

#define  PTE_MARKER_UFFD_WP			BIT(0)

#define  PTE_MARKER_POISONED			BIT(1)

#define  PTE_MARKER_GUARD			BIT(2)
#define  PTE_MARKER_MASK			(BIT(3) - 1)

static inline swp_entry_t make_pte_marker_entry(pte_marker marker)
{
	return swp_entry(SWP_PTE_MARKER, marker);
}

static inline pte_t make_pte_marker(pte_marker marker)
{
	return swp_entry_to_pte(make_pte_marker_entry(marker));
}

static inline swp_entry_t make_poisoned_swp_entry(void)
{
	return make_pte_marker_entry(PTE_MARKER_POISONED);
}

static inline swp_entry_t make_guard_swp_entry(void)
{
	return make_pte_marker_entry(PTE_MARKER_GUARD);
}

struct page_vma_mapped_walk;

#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
extern int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
		struct page *page);

extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw,
		struct page *new);

extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd);

static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
{
	swp_entry_t arch_entry;

	arch_entry = __swp_entry(swp_type(entry), swp_offset(entry));
	return __swp_entry_to_pmd(arch_entry);
}

#else  
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 pmd_t swp_entry_to_pmd(swp_entry_t entry)
{
	return __pmd(0);
}

#endif  

#endif 
#endif 
