1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __LINUX_PAGE_EXT_H 3 #define __LINUX_PAGE_EXT_H 4 5 #include <linux/types.h> 6 #include <linux/stacktrace.h> 7 #include <linux/stackdepot.h> 8 9 struct pglist_data; 10 struct page_ext_operations { 11 size_t offset; 12 size_t size; 13 bool (*need)(void); 14 void (*init)(void); 15 }; 16 17 #ifdef CONFIG_PAGE_EXTENSION 18 19 /* 20 * page_ext->flags bits: 21 * 22 * PAGE_EXT_DEBUG_POISON is set for poisoned pages. This is used to 23 * implement generic debug pagealloc feature. The pages are filled with 24 * poison patterns and set this flag after free_pages(). The poisoned 25 * pages are verified whether the patterns are not corrupted and clear 26 * the flag before alloc_pages(). 27 */ 28 29 enum page_ext_flags { 30 PAGE_EXT_DEBUG_POISON, /* Page is poisoned */ 31 PAGE_EXT_DEBUG_GUARD, 32 PAGE_EXT_OWNER, 33 #if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT) 34 PAGE_EXT_YOUNG, 35 PAGE_EXT_IDLE, 36 #endif 37 }; 38 39 /* 40 * Page Extension can be considered as an extended mem_map. 41 * A page_ext page is associated with every page descriptor. The 42 * page_ext helps us add more information about the page. 43 * All page_ext are allocated at boot or memory hotplug event, 44 * then the page_ext for pfn always exists. 45 */ 46 struct page_ext { 47 unsigned long flags; 48 }; 49 50 extern void pgdat_page_ext_init(struct pglist_data *pgdat); 51 52 #ifdef CONFIG_SPARSEMEM page_ext_init_flatmem(void)53static inline void page_ext_init_flatmem(void) 54 { 55 } 56 extern void page_ext_init(void); 57 #else 58 extern void page_ext_init_flatmem(void); page_ext_init(void)59static inline void page_ext_init(void) 60 { 61 } 62 #endif 63 64 struct page_ext *lookup_page_ext(struct page *page); 65 66 #else /* !CONFIG_PAGE_EXTENSION */ 67 struct page_ext; 68 pgdat_page_ext_init(struct pglist_data * pgdat)69static inline void pgdat_page_ext_init(struct pglist_data *pgdat) 70 { 71 } 72 lookup_page_ext(struct page * page)73static inline struct page_ext *lookup_page_ext(struct page *page) 74 { 75 return NULL; 76 } 77 page_ext_init(void)78static inline void page_ext_init(void) 79 { 80 } 81 page_ext_init_flatmem(void)82static inline void page_ext_init_flatmem(void) 83 { 84 } 85 #endif /* CONFIG_PAGE_EXTENSION */ 86 #endif /* __LINUX_PAGE_EXT_H */ 87