1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_SWAPOPS_H 3 #define _LINUX_SWAPOPS_H 4 5 #include <linux/radix-tree.h> 6 #include <linux/bug.h> 7 #include <linux/mm_types.h> 8 9 #ifdef CONFIG_MMU 10 11 /* 12 * swapcache pages are stored in the swapper_space radix tree. We want to 13 * get good packing density in that tree, so the index should be dense in 14 * the low-order bits. 15 * 16 * We arrange the `type' and `offset' fields so that `type' is at the seven 17 * high-order bits of the swp_entry_t and `offset' is right-aligned in the 18 * remaining bits. Although `type' itself needs only five bits, we allow for 19 * shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry(). 20 * 21 * swp_entry_t's are *never* stored anywhere in their arch-dependent format. 22 */ 23 #define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT) 24 #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1) 25 26 /* 27 * Store a type+offset into a swp_entry_t in an arch-independent format 28 */ 29 static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset) 30 { 31 swp_entry_t ret; 32 33 ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK); 34 return ret; 35 } 36 37 /* 38 * Extract the `type' field from a swp_entry_t. The swp_entry_t is in 39 * arch-independent format 40 */ 41 static inline unsigned swp_type(swp_entry_t entry) 42 { 43 return (entry.val >> SWP_TYPE_SHIFT); 44 } 45 46 /* 47 * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in 48 * arch-independent format 49 */ 50 static inline pgoff_t swp_offset(swp_entry_t entry) 51 { 52 return entry.val & SWP_OFFSET_MASK; 53 } 54 55 /* check whether a pte points to a swap entry */ 56 static inline int is_swap_pte(pte_t pte) 57 { 58 return !pte_none(pte) && !pte_present(pte); 59 } 60 61 /* 62 * Convert the arch-dependent pte representation of a swp_entry_t into an 63 * arch-independent swp_entry_t. 64 */ 65 static inline swp_entry_t pte_to_swp_entry(pte_t pte) 66 { 67 swp_entry_t arch_entry; 68 69 if (pte_swp_soft_dirty(pte)) 70 pte = pte_swp_clear_soft_dirty(pte); 71 arch_entry = __pte_to_swp_entry(pte); 72 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); 73 } 74 75 /* 76 * Convert the arch-independent representation of a swp_entry_t into the 77 * arch-dependent pte representation. 78 */ 79 static inline pte_t swp_entry_to_pte(swp_entry_t entry) 80 { 81 swp_entry_t arch_entry; 82 83 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); 84 return __swp_entry_to_pte(arch_entry); 85 } 86 87 static inline swp_entry_t radix_to_swp_entry(void *arg) 88 { 89 swp_entry_t entry; 90 91 entry.val = xa_to_value(arg); 92 return entry; 93 } 94 95 static inline void *swp_to_radix_entry(swp_entry_t entry) 96 { 97 return xa_mk_value(entry.val); 98 } 99 100 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) 101 static inline swp_entry_t make_device_private_entry(struct page *page, bool write) 102 { 103 return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ, 104 page_to_pfn(page)); 105 } 106 107 static inline bool is_device_private_entry(swp_entry_t entry) 108 { 109 int type = swp_type(entry); 110 return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE; 111 } 112 113 static inline void make_device_private_entry_read(swp_entry_t *entry) 114 { 115 *entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry)); 116 } 117 118 static inline bool is_write_device_private_entry(swp_entry_t entry) 119 { 120 return unlikely(swp_type(entry) == SWP_DEVICE_WRITE); 121 } 122 123 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry) 124 { 125 return swp_offset(entry); 126 } 127 128 static inline struct page *device_private_entry_to_page(swp_entry_t entry) 129 { 130 return pfn_to_page(swp_offset(entry)); 131 } 132 #else /* CONFIG_DEVICE_PRIVATE */ 133 static inline swp_entry_t make_device_private_entry(struct page *page, bool write) 134 { 135 return swp_entry(0, 0); 136 } 137 138 static inline void make_device_private_entry_read(swp_entry_t *entry) 139 { 140 } 141 142 static inline bool is_device_private_entry(swp_entry_t entry) 143 { 144 return false; 145 } 146 147 static inline bool is_write_device_private_entry(swp_entry_t entry) 148 { 149 return false; 150 } 151 152 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry) 153 { 154 return 0; 155 } 156 157 static inline struct page *device_private_entry_to_page(swp_entry_t entry) 158 { 159 return NULL; 160 } 161 #endif /* CONFIG_DEVICE_PRIVATE */ 162 163 #ifdef CONFIG_MIGRATION 164 static inline swp_entry_t make_migration_entry(struct page *page, int write) 165 { 166 BUG_ON(!PageLocked(compound_head(page))); 167 168 return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ, 169 page_to_pfn(page)); 170 } 171 172 static inline int is_migration_entry(swp_entry_t entry) 173 { 174 return unlikely(swp_type(entry) == SWP_MIGRATION_READ || 175 swp_type(entry) == SWP_MIGRATION_WRITE); 176 } 177 178 static inline int is_write_migration_entry(swp_entry_t entry) 179 { 180 return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); 181 } 182 183 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry) 184 { 185 return swp_offset(entry); 186 } 187 188 static inline struct page *migration_entry_to_page(swp_entry_t entry) 189 { 190 struct page *p = pfn_to_page(swp_offset(entry)); 191 /* 192 * Any use of migration entries may only occur while the 193 * corresponding page is locked 194 */ 195 BUG_ON(!PageLocked(compound_head(p))); 196 return p; 197 } 198 199 static inline void make_migration_entry_read(swp_entry_t *entry) 200 { 201 *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); 202 } 203 204 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, 205 spinlock_t *ptl); 206 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, 207 unsigned long address); 208 extern void migration_entry_wait_huge(struct vm_area_struct *vma, 209 struct mm_struct *mm, pte_t *pte); 210 #else 211 212 #define make_migration_entry(page, write) swp_entry(0, 0) 213 static inline int is_migration_entry(swp_entry_t swp) 214 { 215 return 0; 216 } 217 218 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry) 219 { 220 return 0; 221 } 222 223 static inline struct page *migration_entry_to_page(swp_entry_t entry) 224 { 225 return NULL; 226 } 227 228 static inline void make_migration_entry_read(swp_entry_t *entryp) { } 229 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, 230 spinlock_t *ptl) { } 231 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, 232 unsigned long address) { } 233 static inline void migration_entry_wait_huge(struct vm_area_struct *vma, 234 struct mm_struct *mm, pte_t *pte) { } 235 static inline int is_write_migration_entry(swp_entry_t entry) 236 { 237 return 0; 238 } 239 240 #endif 241 242 struct page_vma_mapped_walk; 243 244 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 245 extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 246 struct page *page); 247 248 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 249 struct page *new); 250 251 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd); 252 253 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd) 254 { 255 swp_entry_t arch_entry; 256 257 if (pmd_swp_soft_dirty(pmd)) 258 pmd = pmd_swp_clear_soft_dirty(pmd); 259 arch_entry = __pmd_to_swp_entry(pmd); 260 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); 261 } 262 263 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) 264 { 265 swp_entry_t arch_entry; 266 267 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); 268 return __swp_entry_to_pmd(arch_entry); 269 } 270 271 static inline int is_pmd_migration_entry(pmd_t pmd) 272 { 273 return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd)); 274 } 275 #else 276 static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 277 struct page *page) 278 { 279 BUILD_BUG(); 280 } 281 282 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 283 struct page *new) 284 { 285 BUILD_BUG(); 286 } 287 288 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { } 289 290 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd) 291 { 292 return swp_entry(0, 0); 293 } 294 295 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) 296 { 297 return __pmd(0); 298 } 299 300 static inline int is_pmd_migration_entry(pmd_t pmd) 301 { 302 return 0; 303 } 304 #endif 305 306 #ifdef CONFIG_MEMORY_FAILURE 307 308 extern atomic_long_t num_poisoned_pages __read_mostly; 309 310 /* 311 * Support for hardware poisoned pages 312 */ 313 static inline swp_entry_t make_hwpoison_entry(struct page *page) 314 { 315 BUG_ON(!PageLocked(page)); 316 return swp_entry(SWP_HWPOISON, page_to_pfn(page)); 317 } 318 319 static inline int is_hwpoison_entry(swp_entry_t entry) 320 { 321 return swp_type(entry) == SWP_HWPOISON; 322 } 323 324 static inline void num_poisoned_pages_inc(void) 325 { 326 atomic_long_inc(&num_poisoned_pages); 327 } 328 329 static inline void num_poisoned_pages_dec(void) 330 { 331 atomic_long_dec(&num_poisoned_pages); 332 } 333 334 #else 335 336 static inline swp_entry_t make_hwpoison_entry(struct page *page) 337 { 338 return swp_entry(0, 0); 339 } 340 341 static inline int is_hwpoison_entry(swp_entry_t swp) 342 { 343 return 0; 344 } 345 346 static inline void num_poisoned_pages_inc(void) 347 { 348 } 349 #endif 350 351 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) 352 static inline int non_swap_entry(swp_entry_t entry) 353 { 354 return swp_type(entry) >= MAX_SWAPFILES; 355 } 356 #else 357 static inline int non_swap_entry(swp_entry_t entry) 358 { 359 return 0; 360 } 361 #endif 362 363 #endif /* CONFIG_MMU */ 364 #endif /* _LINUX_SWAPOPS_H */ 365