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 if (pte_swp_uffd_wp(pte)) 72 pte = pte_swp_clear_uffd_wp(pte); 73 arch_entry = __pte_to_swp_entry(pte); 74 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); 75 } 76 77 /* 78 * Convert the arch-independent representation of a swp_entry_t into the 79 * arch-dependent pte representation. 80 */ 81 static inline pte_t swp_entry_to_pte(swp_entry_t entry) 82 { 83 swp_entry_t arch_entry; 84 85 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); 86 return __swp_entry_to_pte(arch_entry); 87 } 88 89 static inline swp_entry_t radix_to_swp_entry(void *arg) 90 { 91 swp_entry_t entry; 92 93 entry.val = xa_to_value(arg); 94 return entry; 95 } 96 97 static inline void *swp_to_radix_entry(swp_entry_t entry) 98 { 99 return xa_mk_value(entry.val); 100 } 101 102 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) 103 static inline swp_entry_t make_device_private_entry(struct page *page, bool write) 104 { 105 return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ, 106 page_to_pfn(page)); 107 } 108 109 static inline bool is_device_private_entry(swp_entry_t entry) 110 { 111 int type = swp_type(entry); 112 return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE; 113 } 114 115 static inline void make_device_private_entry_read(swp_entry_t *entry) 116 { 117 *entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry)); 118 } 119 120 static inline bool is_write_device_private_entry(swp_entry_t entry) 121 { 122 return unlikely(swp_type(entry) == SWP_DEVICE_WRITE); 123 } 124 125 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry) 126 { 127 return swp_offset(entry); 128 } 129 130 static inline struct page *device_private_entry_to_page(swp_entry_t entry) 131 { 132 return pfn_to_page(swp_offset(entry)); 133 } 134 #else /* CONFIG_DEVICE_PRIVATE */ 135 static inline swp_entry_t make_device_private_entry(struct page *page, bool write) 136 { 137 return swp_entry(0, 0); 138 } 139 140 static inline void make_device_private_entry_read(swp_entry_t *entry) 141 { 142 } 143 144 static inline bool is_device_private_entry(swp_entry_t entry) 145 { 146 return false; 147 } 148 149 static inline bool is_write_device_private_entry(swp_entry_t entry) 150 { 151 return false; 152 } 153 154 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry) 155 { 156 return 0; 157 } 158 159 static inline struct page *device_private_entry_to_page(swp_entry_t entry) 160 { 161 return NULL; 162 } 163 #endif /* CONFIG_DEVICE_PRIVATE */ 164 165 #ifdef CONFIG_MIGRATION 166 static inline swp_entry_t make_migration_entry(struct page *page, int write) 167 { 168 BUG_ON(!PageLocked(compound_head(page))); 169 170 return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ, 171 page_to_pfn(page)); 172 } 173 174 static inline int is_migration_entry(swp_entry_t entry) 175 { 176 return unlikely(swp_type(entry) == SWP_MIGRATION_READ || 177 swp_type(entry) == SWP_MIGRATION_WRITE); 178 } 179 180 static inline int is_write_migration_entry(swp_entry_t entry) 181 { 182 return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); 183 } 184 185 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry) 186 { 187 return swp_offset(entry); 188 } 189 190 static inline struct page *migration_entry_to_page(swp_entry_t entry) 191 { 192 struct page *p = pfn_to_page(swp_offset(entry)); 193 /* 194 * Any use of migration entries may only occur while the 195 * corresponding page is locked 196 */ 197 BUG_ON(!PageLocked(compound_head(p))); 198 return p; 199 } 200 201 static inline void make_migration_entry_read(swp_entry_t *entry) 202 { 203 *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); 204 } 205 206 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, 207 spinlock_t *ptl); 208 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, 209 unsigned long address); 210 extern void migration_entry_wait_huge(struct vm_area_struct *vma, 211 struct mm_struct *mm, pte_t *pte); 212 #else 213 214 #define make_migration_entry(page, write) swp_entry(0, 0) 215 static inline int is_migration_entry(swp_entry_t swp) 216 { 217 return 0; 218 } 219 220 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry) 221 { 222 return 0; 223 } 224 225 static inline struct page *migration_entry_to_page(swp_entry_t entry) 226 { 227 return NULL; 228 } 229 230 static inline void make_migration_entry_read(swp_entry_t *entryp) { } 231 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, 232 spinlock_t *ptl) { } 233 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, 234 unsigned long address) { } 235 static inline void migration_entry_wait_huge(struct vm_area_struct *vma, 236 struct mm_struct *mm, pte_t *pte) { } 237 static inline int is_write_migration_entry(swp_entry_t entry) 238 { 239 return 0; 240 } 241 242 #endif 243 244 struct page_vma_mapped_walk; 245 246 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 247 extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 248 struct page *page); 249 250 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 251 struct page *new); 252 253 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd); 254 255 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd) 256 { 257 swp_entry_t arch_entry; 258 259 if (pmd_swp_soft_dirty(pmd)) 260 pmd = pmd_swp_clear_soft_dirty(pmd); 261 arch_entry = __pmd_to_swp_entry(pmd); 262 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); 263 } 264 265 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) 266 { 267 swp_entry_t arch_entry; 268 269 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); 270 return __swp_entry_to_pmd(arch_entry); 271 } 272 273 static inline int is_pmd_migration_entry(pmd_t pmd) 274 { 275 return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd)); 276 } 277 #else 278 static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 279 struct page *page) 280 { 281 BUILD_BUG(); 282 } 283 284 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 285 struct page *new) 286 { 287 BUILD_BUG(); 288 } 289 290 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { } 291 292 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd) 293 { 294 return swp_entry(0, 0); 295 } 296 297 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) 298 { 299 return __pmd(0); 300 } 301 302 static inline int is_pmd_migration_entry(pmd_t pmd) 303 { 304 return 0; 305 } 306 #endif 307 308 #ifdef CONFIG_MEMORY_FAILURE 309 310 extern atomic_long_t num_poisoned_pages __read_mostly; 311 312 /* 313 * Support for hardware poisoned pages 314 */ 315 static inline swp_entry_t make_hwpoison_entry(struct page *page) 316 { 317 BUG_ON(!PageLocked(page)); 318 return swp_entry(SWP_HWPOISON, page_to_pfn(page)); 319 } 320 321 static inline int is_hwpoison_entry(swp_entry_t entry) 322 { 323 return swp_type(entry) == SWP_HWPOISON; 324 } 325 326 static inline void num_poisoned_pages_inc(void) 327 { 328 atomic_long_inc(&num_poisoned_pages); 329 } 330 331 static inline void num_poisoned_pages_dec(void) 332 { 333 atomic_long_dec(&num_poisoned_pages); 334 } 335 336 #else 337 338 static inline swp_entry_t make_hwpoison_entry(struct page *page) 339 { 340 return swp_entry(0, 0); 341 } 342 343 static inline int is_hwpoison_entry(swp_entry_t swp) 344 { 345 return 0; 346 } 347 348 static inline void num_poisoned_pages_inc(void) 349 { 350 } 351 #endif 352 353 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \ 354 defined(CONFIG_DEVICE_PRIVATE) 355 static inline int non_swap_entry(swp_entry_t entry) 356 { 357 return swp_type(entry) >= MAX_SWAPFILES; 358 } 359 #else 360 static inline int non_swap_entry(swp_entry_t entry) 361 { 362 return 0; 363 } 364 #endif 365 366 #endif /* CONFIG_MMU */ 367 #endif /* _LINUX_SWAPOPS_H */ 368