130 lines · c
1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef __LINUX_PAGE_EXT_H3#define __LINUX_PAGE_EXT_H4 5#include <linux/types.h>6#include <linux/stacktrace.h>7 8struct pglist_data;9 10#ifdef CONFIG_PAGE_EXTENSION11/**12 * struct page_ext_operations - per page_ext client operations13 * @offset: Offset to the client's data within page_ext. Offset is returned to14 * the client by page_ext_init.15 * @size: The size of the client data within page_ext.16 * @need: Function that returns true if client requires page_ext.17 * @init: (optional) Called to initialize client once page_exts are allocated.18 * @need_shared_flags: True when client is using shared page_ext->flags19 * field.20 *21 * Each Page Extension client must define page_ext_operations in22 * page_ext_ops array.23 */24struct page_ext_operations {25 size_t offset;26 size_t size;27 bool (*need)(void);28 void (*init)(void);29 bool need_shared_flags;30};31 32/*33 * The page_ext_flags users must set need_shared_flags to true.34 */35enum page_ext_flags {36 PAGE_EXT_OWNER,37 PAGE_EXT_OWNER_ALLOCATED,38#if defined(CONFIG_PAGE_IDLE_FLAG) && !defined(CONFIG_64BIT)39 PAGE_EXT_YOUNG,40 PAGE_EXT_IDLE,41#endif42};43 44/*45 * Page Extension can be considered as an extended mem_map.46 * A page_ext page is associated with every page descriptor. The47 * page_ext helps us add more information about the page.48 * All page_ext are allocated at boot or memory hotplug event,49 * then the page_ext for pfn always exists.50 */51struct page_ext {52 unsigned long flags;53};54 55extern bool early_page_ext;56extern unsigned long page_ext_size;57extern void pgdat_page_ext_init(struct pglist_data *pgdat);58 59static inline bool early_page_ext_enabled(void)60{61 return early_page_ext;62}63 64#ifdef CONFIG_SPARSEMEM65static inline void page_ext_init_flatmem(void)66{67}68extern void page_ext_init(void);69static inline void page_ext_init_flatmem_late(void)70{71}72#else73extern void page_ext_init_flatmem(void);74extern void page_ext_init_flatmem_late(void);75static inline void page_ext_init(void)76{77}78#endif79 80extern struct page_ext *page_ext_get(const struct page *page);81extern void page_ext_put(struct page_ext *page_ext);82 83static inline void *page_ext_data(struct page_ext *page_ext,84 struct page_ext_operations *ops)85{86 return (void *)(page_ext) + ops->offset;87}88 89static inline struct page_ext *page_ext_next(struct page_ext *curr)90{91 void *next = curr;92 next += page_ext_size;93 return next;94}95 96#else /* !CONFIG_PAGE_EXTENSION */97struct page_ext;98 99static inline bool early_page_ext_enabled(void)100{101 return false;102}103 104static inline void pgdat_page_ext_init(struct pglist_data *pgdat)105{106}107 108static inline void page_ext_init(void)109{110}111 112static inline void page_ext_init_flatmem_late(void)113{114}115 116static inline void page_ext_init_flatmem(void)117{118}119 120static inline struct page_ext *page_ext_get(const struct page *page)121{122 return NULL;123}124 125static inline void page_ext_put(struct page_ext *page_ext)126{127}128#endif /* CONFIG_PAGE_EXTENSION */129#endif /* __LINUX_PAGE_EXT_H */130