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 8 /* 9 * swapcache pages are stored in the swapper_space radix tree. We want to 10 * get good packing density in that tree, so the index should be dense in 11 * the low-order bits. 12 * 13 * We arrange the `type' and `offset' fields so that `type' is at the seven 14 * high-order bits of the swp_entry_t and `offset' is right-aligned in the 15 * remaining bits. Although `type' itself needs only five bits, we allow for 16 * shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry(). 17 * 18 * swp_entry_t's are *never* stored anywhere in their arch-dependent format. 19 */ 20 #define SWP_TYPE_SHIFT(e) ((sizeof(e.val) * 8) - \ 21 (MAX_SWAPFILES_SHIFT + RADIX_TREE_EXCEPTIONAL_SHIFT)) 22 #define SWP_OFFSET_MASK(e) ((1UL << SWP_TYPE_SHIFT(e)) - 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(ret)) | 32 (offset & SWP_OFFSET_MASK(ret)); 33 return ret; 34 } 35 36 /* 37 * Extract the `type' field from a swp_entry_t. The swp_entry_t is in 38 * arch-independent format 39 */ 40 static inline unsigned swp_type(swp_entry_t entry) 41 { 42 return (entry.val >> SWP_TYPE_SHIFT(entry)); 43 } 44 45 /* 46 * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in 47 * arch-independent format 48 */ 49 static inline pgoff_t swp_offset(swp_entry_t entry) 50 { 51 return entry.val & SWP_OFFSET_MASK(entry); 52 } 53 54 #ifdef CONFIG_MMU 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 #endif 61 62 /* 63 * Convert the arch-dependent pte representation of a swp_entry_t into an 64 * arch-independent swp_entry_t. 65 */ 66 static inline swp_entry_t pte_to_swp_entry(pte_t pte) 67 { 68 swp_entry_t arch_entry; 69 70 if (pte_swp_soft_dirty(pte)) 71 pte = pte_swp_clear_soft_dirty(pte); 72 arch_entry = __pte_to_swp_entry(pte); 73 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); 74 } 75 76 /* 77 * Convert the arch-independent representation of a swp_entry_t into the 78 * arch-dependent pte representation. 79 */ 80 static inline pte_t swp_entry_to_pte(swp_entry_t entry) 81 { 82 swp_entry_t arch_entry; 83 84 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); 85 return __swp_entry_to_pte(arch_entry); 86 } 87 88 static inline swp_entry_t radix_to_swp_entry(void *arg) 89 { 90 swp_entry_t entry; 91 92 entry.val = (unsigned long)arg >> RADIX_TREE_EXCEPTIONAL_SHIFT; 93 return entry; 94 } 95 96 static inline void *swp_to_radix_entry(swp_entry_t entry) 97 { 98 unsigned long value; 99 100 value = entry.val << RADIX_TREE_EXCEPTIONAL_SHIFT; 101 return (void *)(value | RADIX_TREE_EXCEPTIONAL_ENTRY); 102 } 103 104 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) 105 static inline swp_entry_t make_device_private_entry(struct page *page, bool write) 106 { 107 return swp_entry(write ? SWP_DEVICE_WRITE : SWP_DEVICE_READ, 108 page_to_pfn(page)); 109 } 110 111 static inline bool is_device_private_entry(swp_entry_t entry) 112 { 113 int type = swp_type(entry); 114 return type == SWP_DEVICE_READ || type == SWP_DEVICE_WRITE; 115 } 116 117 static inline void make_device_private_entry_read(swp_entry_t *entry) 118 { 119 *entry = swp_entry(SWP_DEVICE_READ, swp_offset(*entry)); 120 } 121 122 static inline bool is_write_device_private_entry(swp_entry_t entry) 123 { 124 return unlikely(swp_type(entry) == SWP_DEVICE_WRITE); 125 } 126 127 static inline struct page *device_private_entry_to_page(swp_entry_t entry) 128 { 129 return pfn_to_page(swp_offset(entry)); 130 } 131 132 int device_private_entry_fault(struct vm_area_struct *vma, 133 unsigned long addr, 134 swp_entry_t entry, 135 unsigned int flags, 136 pmd_t *pmdp); 137 #else /* CONFIG_DEVICE_PRIVATE */ 138 static inline swp_entry_t make_device_private_entry(struct page *page, bool write) 139 { 140 return swp_entry(0, 0); 141 } 142 143 static inline void make_device_private_entry_read(swp_entry_t *entry) 144 { 145 } 146 147 static inline bool is_device_private_entry(swp_entry_t entry) 148 { 149 return false; 150 } 151 152 static inline bool is_write_device_private_entry(swp_entry_t entry) 153 { 154 return false; 155 } 156 157 static inline struct page *device_private_entry_to_page(swp_entry_t entry) 158 { 159 return NULL; 160 } 161 162 static inline int device_private_entry_fault(struct vm_area_struct *vma, 163 unsigned long addr, 164 swp_entry_t entry, 165 unsigned int flags, 166 pmd_t *pmdp) 167 { 168 return VM_FAULT_SIGBUS; 169 } 170 #endif /* CONFIG_DEVICE_PRIVATE */ 171 172 #ifdef CONFIG_MIGRATION 173 static inline swp_entry_t make_migration_entry(struct page *page, int write) 174 { 175 BUG_ON(!PageLocked(compound_head(page))); 176 177 return swp_entry(write ? SWP_MIGRATION_WRITE : SWP_MIGRATION_READ, 178 page_to_pfn(page)); 179 } 180 181 static inline int is_migration_entry(swp_entry_t entry) 182 { 183 return unlikely(swp_type(entry) == SWP_MIGRATION_READ || 184 swp_type(entry) == SWP_MIGRATION_WRITE); 185 } 186 187 static inline int is_write_migration_entry(swp_entry_t entry) 188 { 189 return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); 190 } 191 192 static inline struct page *migration_entry_to_page(swp_entry_t entry) 193 { 194 struct page *p = pfn_to_page(swp_offset(entry)); 195 /* 196 * Any use of migration entries may only occur while the 197 * corresponding page is locked 198 */ 199 BUG_ON(!PageLocked(compound_head(p))); 200 return p; 201 } 202 203 static inline void make_migration_entry_read(swp_entry_t *entry) 204 { 205 *entry = swp_entry(SWP_MIGRATION_READ, swp_offset(*entry)); 206 } 207 208 extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, 209 spinlock_t *ptl); 210 extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, 211 unsigned long address); 212 extern void migration_entry_wait_huge(struct vm_area_struct *vma, 213 struct mm_struct *mm, pte_t *pte); 214 #else 215 216 #define make_migration_entry(page, write) swp_entry(0, 0) 217 static inline int is_migration_entry(swp_entry_t swp) 218 { 219 return 0; 220 } 221 static inline struct page *migration_entry_to_page(swp_entry_t entry) 222 { 223 return NULL; 224 } 225 226 static inline void make_migration_entry_read(swp_entry_t *entryp) { } 227 static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep, 228 spinlock_t *ptl) { } 229 static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, 230 unsigned long address) { } 231 static inline void migration_entry_wait_huge(struct vm_area_struct *vma, 232 struct mm_struct *mm, pte_t *pte) { } 233 static inline int is_write_migration_entry(swp_entry_t entry) 234 { 235 return 0; 236 } 237 238 #endif 239 240 struct page_vma_mapped_walk; 241 242 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 243 extern void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 244 struct page *page); 245 246 extern void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 247 struct page *new); 248 249 extern void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd); 250 251 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd) 252 { 253 swp_entry_t arch_entry; 254 255 if (pmd_swp_soft_dirty(pmd)) 256 pmd = pmd_swp_clear_soft_dirty(pmd); 257 arch_entry = __pmd_to_swp_entry(pmd); 258 return swp_entry(__swp_type(arch_entry), __swp_offset(arch_entry)); 259 } 260 261 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) 262 { 263 swp_entry_t arch_entry; 264 265 arch_entry = __swp_entry(swp_type(entry), swp_offset(entry)); 266 return __swp_entry_to_pmd(arch_entry); 267 } 268 269 static inline int is_pmd_migration_entry(pmd_t pmd) 270 { 271 return !pmd_present(pmd) && is_migration_entry(pmd_to_swp_entry(pmd)); 272 } 273 #else 274 static inline void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, 275 struct page *page) 276 { 277 BUILD_BUG(); 278 } 279 280 static inline void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, 281 struct page *new) 282 { 283 BUILD_BUG(); 284 } 285 286 static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { } 287 288 static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd) 289 { 290 return swp_entry(0, 0); 291 } 292 293 static inline pmd_t swp_entry_to_pmd(swp_entry_t entry) 294 { 295 return __pmd(0); 296 } 297 298 static inline int is_pmd_migration_entry(pmd_t pmd) 299 { 300 return 0; 301 } 302 #endif 303 304 #ifdef CONFIG_MEMORY_FAILURE 305 306 extern atomic_long_t num_poisoned_pages __read_mostly; 307 308 /* 309 * Support for hardware poisoned pages 310 */ 311 static inline swp_entry_t make_hwpoison_entry(struct page *page) 312 { 313 BUG_ON(!PageLocked(page)); 314 return swp_entry(SWP_HWPOISON, page_to_pfn(page)); 315 } 316 317 static inline int is_hwpoison_entry(swp_entry_t entry) 318 { 319 return swp_type(entry) == SWP_HWPOISON; 320 } 321 322 static inline bool test_set_page_hwpoison(struct page *page) 323 { 324 return TestSetPageHWPoison(page); 325 } 326 327 static inline void num_poisoned_pages_inc(void) 328 { 329 atomic_long_inc(&num_poisoned_pages); 330 } 331 332 static inline void num_poisoned_pages_dec(void) 333 { 334 atomic_long_dec(&num_poisoned_pages); 335 } 336 337 #else 338 339 static inline swp_entry_t make_hwpoison_entry(struct page *page) 340 { 341 return swp_entry(0, 0); 342 } 343 344 static inline int is_hwpoison_entry(swp_entry_t swp) 345 { 346 return 0; 347 } 348 349 static inline bool test_set_page_hwpoison(struct page *page) 350 { 351 return false; 352 } 353 354 static inline void num_poisoned_pages_inc(void) 355 { 356 } 357 #endif 358 359 #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) 360 static inline int non_swap_entry(swp_entry_t entry) 361 { 362 return swp_type(entry) >= MAX_SWAPFILES; 363 } 364 #else 365 static inline int non_swap_entry(swp_entry_t entry) 366 { 367 return 0; 368 } 369 #endif 370 371 #endif /* _LINUX_SWAPOPS_H */ 372