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 /* 10 * swapcache pages are stored in the swapper_space radix tree. We want to 11 * get good packing density in that tree, so the index should be dense in 12 * the low-order bits. 13 * 14 * We arrange the `type' and `offset' fields so that `type' is at the seven 15 * high-order bits of the swp_entry_t and `offset' is right-aligned in the 16 * remaining bits. Although `type' itself needs only five bits, we allow for 17 * shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry(). 18 * 19 * swp_entry_t's are *never* stored anywhere in their arch-dependent format. 20 */ 21 #define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT) 22 #define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1) 23 24 /* 25 * Store a type+offset into a swp_entry_t in an arch-independent format 26 */ 27 static inline swp_entry_t swp_entry(unsigned long type, pgoff_t offset) 28 { 29 swp_entry_t ret; 30 31 ret.val = (type << SWP_TYPE_SHIFT) | (offset & SWP_OFFSET_MASK); 32 return ret; 33 } 34 35 /* 36 * Extract the `type' field from a swp_entry_t. The swp_entry_t is in 37 * arch-independent format 38 */ 39 static inline unsigned swp_type(swp_entry_t entry) 40 { 41 return (entry.val >> SWP_TYPE_SHIFT); 42 } 43 44 /* 45 * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in 46 * arch-independent format 47 */ 48 static inline pgoff_t swp_offset(swp_entry_t entry) 49 { 50 return entry.val & SWP_OFFSET_MASK; 51 } 52 53 #ifdef CONFIG_MMU 54 /* check whether a pte points to a swap entry */ 55 static inline int is_swap_pte(pte_t pte) 56 { 57 return !pte_none(pte) && !pte_present(pte); 58 } 59 #endif 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 } 132 133 vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, 134 unsigned long addr, 135 swp_entry_t entry, 136 unsigned int flags, 137 pmd_t *pmdp); 138 #else /* CONFIG_DEVICE_PRIVATE */ 139 static inline swp_entry_t make_device_private_entry(struct page *page, bool write) 140 { 141 return swp_entry(0, 0); 142 } 143 144 static inline void make_device_private_entry_read(swp_entry_t *entry) 145 { 146 } 147 148 static inline bool is_device_private_entry(swp_entry_t entry) 149 { 150 return false; 151 } 152 153 static inline bool is_write_device_private_entry(swp_entry_t entry) 154 { 155 return false; 156 } 157 158 static inline unsigned long device_private_entry_to_pfn(swp_entry_t entry) 159 { 160 return 0; 161 } 162 163 static inline struct page *device_private_entry_to_page(swp_entry_t entry) 164 { 165 return NULL; 166 } 167 168 static inline vm_fault_t device_private_entry_fault(struct vm_area_struct *vma, 169 unsigned long addr, 170 swp_entry_t entry, 171 unsigned int flags, 172 pmd_t *pmdp) 173 { 174 return VM_FAULT_SIGBUS; 175 } 176 #endif /* CONFIG_DEVICE_PRIVATE */ 177 178 #ifdef CONFIG_MIGRATION 179 static inline swp_entry_t make_migration_entry(struct page *page, int write) 180 { 181 BUG_ON(!PageLocked(compound_head(page))); 182 183 return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ, 184 page_to_pfn(page)); 185 } 186 187 static inline int is_migration_entry(swp_entry_t entry) 188 { 189 return unlikely(swp_type(entry) == SWP_MIGRATION_READ || 190 swp_type(entry) == SWP_MIGRATION_WRITE); 191 } 192 193 static inline int is_write_migration_entry(swp_entry_t entry) 194 { 195 return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); 196 } 197 198 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry) 199 { 200 return swp_offset(entry); 201 } 202 203 static inline struct page *migration_entry_to_page(swp_entry_t entry) 204 { 205 struct page *p = pfn_to_page(swp_offset(entry)); 206 /* 207 * Any use of migration entries may only occur while the 208 * corresponding page is locked 209 */ 210 BUG_ON(!PageLocked(compound_head(p))); 211 return p; 212 } 213 214 static inline void make_migration_entry_read(swp_entry_t *entry) 215 { 216 *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); 217 } 218 219 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, 220 spinlock_t *ptl); 221 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, 222 unsigned long address); 223 extern void migration_entry_wait_huge(struct vm_area_struct *vma, 224 struct mm_struct *mm, pte_t *pte); 225 #else 226 227 #define make_migration_entry(page, write) swp_entry(0, 0) 228 static inline int is_migration_entry(swp_entry_t swp) 229 { 230 return 0; 231 } 232 233 static inline unsigned long migration_entry_to_pfn(swp_entry_t entry) 234 { 235 return 0; 236 } 237 238 static inline struct page *migration_entry_to_page(swp_entry_t entry) 239 { 240 return NULL; 241 } 242 243 static inline void make_migration_entry_read(swp_entry_t *entryp) { } 244 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, 245 spinlock_t *ptl) { } 246 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, 247 unsigned long address) { } 248 static inline void migration_entry_wait_huge(struct vm_area_struct *vma, 249 struct mm_struct *mm, pte_t *pte) { } 250 static inline int is_write_migration_entry(swp_entry_t entry) 251 { 252 return 0; 253 } 254 255 #endif 256 257 struct page_vma_mapped_walk; 258 259 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 260 extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 261 struct page *page); 262 263 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 264 struct page *new); 265 266 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd); 267 268 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd) 269 { 270 swp_entry_t arch_entry; 271 272 if (pmd_swp_soft_dirty(pmd)) 273 pmd = pmd_swp_clear_soft_dirty(pmd); 274 arch_entry = __pmd_to_swp_entry(pmd); 275 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); 276 } 277 278 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) 279 { 280 swp_entry_t arch_entry; 281 282 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); 283 return __swp_entry_to_pmd(arch_entry); 284 } 285 286 static inline int is_pmd_migration_entry(pmd_t pmd) 287 { 288 return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd)); 289 } 290 #else 291 static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 292 struct page *page) 293 { 294 BUILD_BUG(); 295 } 296 297 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 298 struct page *new) 299 { 300 BUILD_BUG(); 301 } 302 303 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { } 304 305 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd) 306 { 307 return swp_entry(0, 0); 308 } 309 310 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) 311 { 312 return __pmd(0); 313 } 314 315 static inline int is_pmd_migration_entry(pmd_t pmd) 316 { 317 return 0; 318 } 319 #endif 320 321 #ifdef CONFIG_MEMORY_FAILURE 322 323 extern atomic_long_t num_poisoned_pages __read_mostly; 324 325 /* 326 * Support for hardware poisoned pages 327 */ 328 static inline swp_entry_t make_hwpoison_entry(struct page *page) 329 { 330 BUG_ON(!PageLocked(page)); 331 return swp_entry(SWP_HWPOISON, page_to_pfn(page)); 332 } 333 334 static inline int is_hwpoison_entry(swp_entry_t entry) 335 { 336 return swp_type(entry) == SWP_HWPOISON; 337 } 338 339 static inline void num_poisoned_pages_inc(void) 340 { 341 atomic_long_inc(&num_poisoned_pages); 342 } 343 344 static inline void num_poisoned_pages_dec(void) 345 { 346 atomic_long_dec(&num_poisoned_pages); 347 } 348 349 #else 350 351 static inline swp_entry_t make_hwpoison_entry(struct page *page) 352 { 353 return swp_entry(0, 0); 354 } 355 356 static inline int is_hwpoison_entry(swp_entry_t swp) 357 { 358 return 0; 359 } 360 361 static inline void num_poisoned_pages_inc(void) 362 { 363 } 364 #endif 365 366 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) 367 static inline int non_swap_entry(swp_entry_t entry) 368 { 369 return swp_type(entry) >= MAX_SWAPFILES; 370 } 371 #else 372 static inline int non_swap_entry(swp_entry_t entry) 373 { 374 return 0; 375 } 376 #endif 377 378 #endif /* _LINUX_SWAPOPS_H */ 379