1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Written by Mark Hemment, 1996 ([email protected]). 4 * 5 * (C) SGI 2006, Christoph Lameter 6 * Cleaned up and restructured to ease the addition of alternative 7 * implementations of SLAB allocators. 8 * (C) Linux Foundation 2008-2013 9 * Unified interface for all slab allocators 10 */ 11 12 #ifndef _LINUX_SLAB_H 13 #define _LINUX_SLAB_H 14 15 #include <linux/cache.h> 16 #include <linux/gfp.h> 17 #include <linux/overflow.h> 18 #include <linux/types.h> 19 #include <linux/workqueue.h> 20 #include <linux/percpu-refcount.h> 21 #include <linux/cleanup.h> 22 #include <linux/hash.h> 23 24 enum _slab_flag_bits { 25 _SLAB_CONSISTENCY_CHECKS, 26 _SLAB_RED_ZONE, 27 _SLAB_POISON, 28 _SLAB_KMALLOC, 29 _SLAB_HWCACHE_ALIGN, 30 _SLAB_CACHE_DMA, 31 _SLAB_CACHE_DMA32, 32 _SLAB_STORE_USER, 33 _SLAB_PANIC, 34 _SLAB_TYPESAFE_BY_RCU, 35 _SLAB_TRACE, 36 #ifdef CONFIG_DEBUG_OBJECTS 37 _SLAB_DEBUG_OBJECTS, 38 #endif 39 _SLAB_NOLEAKTRACE, 40 _SLAB_NO_MERGE, 41 #ifdef CONFIG_FAILSLAB 42 _SLAB_FAILSLAB, 43 #endif 44 #ifdef CONFIG_MEMCG 45 _SLAB_ACCOUNT, 46 #endif 47 #ifdef CONFIG_KASAN_GENERIC 48 _SLAB_KASAN, 49 #endif 50 _SLAB_NO_USER_FLAGS, 51 #ifdef CONFIG_KFENCE 52 _SLAB_SKIP_KFENCE, 53 #endif 54 #ifndef CONFIG_SLUB_TINY 55 _SLAB_RECLAIM_ACCOUNT, 56 #endif 57 _SLAB_OBJECT_POISON, 58 _SLAB_CMPXCHG_DOUBLE, 59 #ifdef CONFIG_SLAB_OBJ_EXT 60 _SLAB_NO_OBJ_EXT, 61 #endif 62 _SLAB_FLAGS_LAST_BIT 63 }; 64 65 #define __SLAB_FLAG_BIT(nr) ((slab_flags_t __force)(1U << (nr))) 66 #define __SLAB_FLAG_UNUSED ((slab_flags_t __force)(0U)) 67 68 /* 69 * Flags to pass to kmem_cache_create(). 70 * The ones marked DEBUG need CONFIG_SLUB_DEBUG enabled, otherwise are no-op 71 */ 72 /* DEBUG: Perform (expensive) checks on alloc/free */ 73 #define SLAB_CONSISTENCY_CHECKS __SLAB_FLAG_BIT(_SLAB_CONSISTENCY_CHECKS) 74 /* DEBUG: Red zone objs in a cache */ 75 #define SLAB_RED_ZONE __SLAB_FLAG_BIT(_SLAB_RED_ZONE) 76 /* DEBUG: Poison objects */ 77 #define SLAB_POISON __SLAB_FLAG_BIT(_SLAB_POISON) 78 /* Indicate a kmalloc slab */ 79 #define SLAB_KMALLOC __SLAB_FLAG_BIT(_SLAB_KMALLOC) 80 /* Align objs on cache lines */ 81 #define SLAB_HWCACHE_ALIGN __SLAB_FLAG_BIT(_SLAB_HWCACHE_ALIGN) 82 /* Use GFP_DMA memory */ 83 #define SLAB_CACHE_DMA __SLAB_FLAG_BIT(_SLAB_CACHE_DMA) 84 /* Use GFP_DMA32 memory */ 85 #define SLAB_CACHE_DMA32 __SLAB_FLAG_BIT(_SLAB_CACHE_DMA32) 86 /* DEBUG: Store the last owner for bug hunting */ 87 #define SLAB_STORE_USER __SLAB_FLAG_BIT(_SLAB_STORE_USER) 88 /* Panic if kmem_cache_create() fails */ 89 #define SLAB_PANIC __SLAB_FLAG_BIT(_SLAB_PANIC) 90 /* 91 * SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS! 92 * 93 * This delays freeing the SLAB page by a grace period, it does _NOT_ 94 * delay object freeing. This means that if you do kmem_cache_free() 95 * that memory location is free to be reused at any time. Thus it may 96 * be possible to see another object there in the same RCU grace period. 97 * 98 * This feature only ensures the memory location backing the object 99 * stays valid, the trick to using this is relying on an independent 100 * object validation pass. Something like: 101 * 102 * begin: 103 * rcu_read_lock(); 104 * obj = lockless_lookup(key); 105 * if (obj) { 106 * if (!try_get_ref(obj)) // might fail for free objects 107 * rcu_read_unlock(); 108 * goto begin; 109 * 110 * if (obj->key != key) { // not the object we expected 111 * put_ref(obj); 112 * rcu_read_unlock(); 113 * goto begin; 114 * } 115 * } 116 * rcu_read_unlock(); 117 * 118 * This is useful if we need to approach a kernel structure obliquely, 119 * from its address obtained without the usual locking. We can lock 120 * the structure to stabilize it and check it's still at the given address, 121 * only if we can be sure that the memory has not been meanwhile reused 122 * for some other kind of object (which our subsystem's lock might corrupt). 123 * 124 * rcu_read_lock before reading the address, then rcu_read_unlock after 125 * taking the spinlock within the structure expected at that address. 126 * 127 * Note that it is not possible to acquire a lock within a structure 128 * allocated with SLAB_TYPESAFE_BY_RCU without first acquiring a reference 129 * as described above. The reason is that SLAB_TYPESAFE_BY_RCU pages 130 * are not zeroed before being given to the slab, which means that any 131 * locks must be initialized after each and every kmem_struct_alloc(). 132 * Alternatively, make the ctor passed to kmem_cache_create() initialize 133 * the locks at page-allocation time, as is done in __i915_request_ctor(), 134 * sighand_ctor(), and anon_vma_ctor(). Such a ctor permits readers 135 * to safely acquire those ctor-initialized locks under rcu_read_lock() 136 * protection. 137 * 138 * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU. 139 */ 140 /* Defer freeing slabs to RCU */ 141 #define SLAB_TYPESAFE_BY_RCU __SLAB_FLAG_BIT(_SLAB_TYPESAFE_BY_RCU) 142 /* Trace allocations and frees */ 143 #define SLAB_TRACE __SLAB_FLAG_BIT(_SLAB_TRACE) 144 145 /* Flag to prevent checks on free */ 146 #ifdef CONFIG_DEBUG_OBJECTS 147 # define SLAB_DEBUG_OBJECTS __SLAB_FLAG_BIT(_SLAB_DEBUG_OBJECTS) 148 #else 149 # define SLAB_DEBUG_OBJECTS __SLAB_FLAG_UNUSED 150 #endif 151 152 /* Avoid kmemleak tracing */ 153 #define SLAB_NOLEAKTRACE __SLAB_FLAG_BIT(_SLAB_NOLEAKTRACE) 154 155 /* 156 * Prevent merging with compatible kmem caches. This flag should be used 157 * cautiously. Valid use cases: 158 * 159 * - caches created for self-tests (e.g. kunit) 160 * - general caches created and used by a subsystem, only when a 161 * (subsystem-specific) debug option is enabled 162 * - performance critical caches, should be very rare and consulted with slab 163 * maintainers, and not used together with CONFIG_SLUB_TINY 164 */ 165 #define SLAB_NO_MERGE __SLAB_FLAG_BIT(_SLAB_NO_MERGE) 166 167 /* Fault injection mark */ 168 #ifdef CONFIG_FAILSLAB 169 # define SLAB_FAILSLAB __SLAB_FLAG_BIT(_SLAB_FAILSLAB) 170 #else 171 # define SLAB_FAILSLAB __SLAB_FLAG_UNUSED 172 #endif 173 /* Account to memcg */ 174 #ifdef CONFIG_MEMCG 175 # define SLAB_ACCOUNT __SLAB_FLAG_BIT(_SLAB_ACCOUNT) 176 #else 177 # define SLAB_ACCOUNT __SLAB_FLAG_UNUSED 178 #endif 179 180 #ifdef CONFIG_KASAN_GENERIC 181 #define SLAB_KASAN __SLAB_FLAG_BIT(_SLAB_KASAN) 182 #else 183 #define SLAB_KASAN __SLAB_FLAG_UNUSED 184 #endif 185 186 /* 187 * Ignore user specified debugging flags. 188 * Intended for caches created for self-tests so they have only flags 189 * specified in the code and other flags are ignored. 190 */ 191 #define SLAB_NO_USER_FLAGS __SLAB_FLAG_BIT(_SLAB_NO_USER_FLAGS) 192 193 #ifdef CONFIG_KFENCE 194 #define SLAB_SKIP_KFENCE __SLAB_FLAG_BIT(_SLAB_SKIP_KFENCE) 195 #else 196 #define SLAB_SKIP_KFENCE __SLAB_FLAG_UNUSED 197 #endif 198 199 /* The following flags affect the page allocator grouping pages by mobility */ 200 /* Objects are reclaimable */ 201 #ifndef CONFIG_SLUB_TINY 202 #define SLAB_RECLAIM_ACCOUNT __SLAB_FLAG_BIT(_SLAB_RECLAIM_ACCOUNT) 203 #else 204 #define SLAB_RECLAIM_ACCOUNT __SLAB_FLAG_UNUSED 205 #endif 206 #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */ 207 208 /* Slab created using create_boot_cache */ 209 #ifdef CONFIG_SLAB_OBJ_EXT 210 #define SLAB_NO_OBJ_EXT __SLAB_FLAG_BIT(_SLAB_NO_OBJ_EXT) 211 #else 212 #define SLAB_NO_OBJ_EXT __SLAB_FLAG_UNUSED 213 #endif 214 215 /* 216 * freeptr_t represents a SLUB freelist pointer, which might be encoded 217 * and not dereferenceable if CONFIG_SLAB_FREELIST_HARDENED is enabled. 218 */ 219 typedef struct { unsigned long v; } freeptr_t; 220 221 /* 222 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests. 223 * 224 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault. 225 * 226 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can. 227 * Both make kfree a no-op. 228 */ 229 #define ZERO_SIZE_PTR ((void *)16) 230 231 #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \ 232 (unsigned long)ZERO_SIZE_PTR) 233 234 #include <linux/kasan.h> 235 236 struct list_lru; 237 struct mem_cgroup; 238 /* 239 * struct kmem_cache related prototypes 240 */ 241 bool slab_is_available(void); 242 243 /** 244 * struct kmem_cache_args - Less common arguments for kmem_cache_create() 245 * 246 * Any uninitialized fields of the structure are interpreted as unused. The 247 * exception is @freeptr_offset where %0 is a valid value, so 248 * @use_freeptr_offset must be also set to %true in order to interpret the field 249 * as used. For @useroffset %0 is also valid, but only with non-%0 250 * @usersize. 251 * 252 * When %NULL args is passed to kmem_cache_create(), it is equivalent to all 253 * fields unused. 254 */ 255 struct kmem_cache_args { 256 /** 257 * @align: The required alignment for the objects. 258 * 259 * %0 means no specific alignment is requested. 260 */ 261 unsigned int align; 262 /** 263 * @useroffset: Usercopy region offset. 264 * 265 * %0 is a valid offset, when @usersize is non-%0 266 */ 267 unsigned int useroffset; 268 /** 269 * @usersize: Usercopy region size. 270 * 271 * %0 means no usercopy region is specified. 272 */ 273 unsigned int usersize; 274 /** 275 * @freeptr_offset: Custom offset for the free pointer 276 * in &SLAB_TYPESAFE_BY_RCU caches 277 * 278 * By default &SLAB_TYPESAFE_BY_RCU caches place the free pointer 279 * outside of the object. This might cause the object to grow in size. 280 * Cache creators that have a reason to avoid this can specify a custom 281 * free pointer offset in their struct where the free pointer will be 282 * placed. 283 * 284 * Note that placing the free pointer inside the object requires the 285 * caller to ensure that no fields are invalidated that are required to 286 * guard against object recycling (See &SLAB_TYPESAFE_BY_RCU for 287 * details). 288 * 289 * Using %0 as a value for @freeptr_offset is valid. If @freeptr_offset 290 * is specified, %use_freeptr_offset must be set %true. 291 * 292 * Note that @ctor currently isn't supported with custom free pointers 293 * as a @ctor requires an external free pointer. 294 */ 295 unsigned int freeptr_offset; 296 /** 297 * @use_freeptr_offset: Whether a @freeptr_offset is used. 298 */ 299 bool use_freeptr_offset; 300 /** 301 * @ctor: A constructor for the objects. 302 * 303 * The constructor is invoked for each object in a newly allocated slab 304 * page. It is the cache user's responsibility to free object in the 305 * same state as after calling the constructor, or deal appropriately 306 * with any differences between a freshly constructed and a reallocated 307 * object. 308 * 309 * %NULL means no constructor. 310 */ 311 void (*ctor)(void *); 312 }; 313 314 struct kmem_cache *__kmem_cache_create_args(const char *name, 315 unsigned int object_size, 316 struct kmem_cache_args *args, 317 slab_flags_t flags); 318 static inline struct kmem_cache * 319 __kmem_cache_create(const char *name, unsigned int size, unsigned int align, 320 slab_flags_t flags, void (*ctor)(void *)) 321 { 322 struct kmem_cache_args kmem_args = { 323 .align = align, 324 .ctor = ctor, 325 }; 326 327 return __kmem_cache_create_args(name, size, &kmem_args, flags); 328 } 329 330 /** 331 * kmem_cache_create_usercopy - Create a kmem cache with a region suitable 332 * for copying to userspace. 333 * @name: A string which is used in /proc/slabinfo to identify this cache. 334 * @size: The size of objects to be created in this cache. 335 * @align: The required alignment for the objects. 336 * @flags: SLAB flags 337 * @useroffset: Usercopy region offset 338 * @usersize: Usercopy region size 339 * @ctor: A constructor for the objects, or %NULL. 340 * 341 * This is a legacy wrapper, new code should use either KMEM_CACHE_USERCOPY() 342 * if whitelisting a single field is sufficient, or kmem_cache_create() with 343 * the necessary parameters passed via the args parameter (see 344 * &struct kmem_cache_args) 345 * 346 * Return: a pointer to the cache on success, NULL on failure. 347 */ 348 static inline struct kmem_cache * 349 kmem_cache_create_usercopy(const char *name, unsigned int size, 350 unsigned int align, slab_flags_t flags, 351 unsigned int useroffset, unsigned int usersize, 352 void (*ctor)(void *)) 353 { 354 struct kmem_cache_args kmem_args = { 355 .align = align, 356 .ctor = ctor, 357 .useroffset = useroffset, 358 .usersize = usersize, 359 }; 360 361 return __kmem_cache_create_args(name, size, &kmem_args, flags); 362 } 363 364 /* If NULL is passed for @args, use this variant with default arguments. */ 365 static inline struct kmem_cache * 366 __kmem_cache_default_args(const char *name, unsigned int size, 367 struct kmem_cache_args *args, 368 slab_flags_t flags) 369 { 370 struct kmem_cache_args kmem_default_args = {}; 371 372 /* Make sure we don't get passed garbage. */ 373 if (WARN_ON_ONCE(args)) 374 return ERR_PTR(-EINVAL); 375 376 return __kmem_cache_create_args(name, size, &kmem_default_args, flags); 377 } 378 379 /** 380 * kmem_cache_create - Create a kmem cache. 381 * @__name: A string which is used in /proc/slabinfo to identify this cache. 382 * @__object_size: The size of objects to be created in this cache. 383 * @__args: Optional arguments, see &struct kmem_cache_args. Passing %NULL 384 * means defaults will be used for all the arguments. 385 * 386 * This is currently implemented as a macro using ``_Generic()`` to call 387 * either the new variant of the function, or a legacy one. 388 * 389 * The new variant has 4 parameters: 390 * ``kmem_cache_create(name, object_size, args, flags)`` 391 * 392 * See __kmem_cache_create_args() which implements this. 393 * 394 * The legacy variant has 5 parameters: 395 * ``kmem_cache_create(name, object_size, align, flags, ctor)`` 396 * 397 * The align and ctor parameters map to the respective fields of 398 * &struct kmem_cache_args 399 * 400 * Context: Cannot be called within a interrupt, but can be interrupted. 401 * 402 * Return: a pointer to the cache on success, NULL on failure. 403 */ 404 #define kmem_cache_create(__name, __object_size, __args, ...) \ 405 _Generic((__args), \ 406 struct kmem_cache_args *: __kmem_cache_create_args, \ 407 void *: __kmem_cache_default_args, \ 408 default: __kmem_cache_create)(__name, __object_size, __args, __VA_ARGS__) 409 410 void kmem_cache_destroy(struct kmem_cache *s); 411 int kmem_cache_shrink(struct kmem_cache *s); 412 413 /* 414 * Please use this macro to create slab caches. Simply specify the 415 * name of the structure and maybe some flags that are listed above. 416 * 417 * The alignment of the struct determines object alignment. If you 418 * f.e. add ____cacheline_aligned_in_smp to the struct declaration 419 * then the objects will be properly aligned in SMP configurations. 420 */ 421 #define KMEM_CACHE(__struct, __flags) \ 422 __kmem_cache_create_args(#__struct, sizeof(struct __struct), \ 423 &(struct kmem_cache_args) { \ 424 .align = __alignof__(struct __struct), \ 425 }, (__flags)) 426 427 /* 428 * To whitelist a single field for copying to/from usercopy, use this 429 * macro instead for KMEM_CACHE() above. 430 */ 431 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \ 432 __kmem_cache_create_args(#__struct, sizeof(struct __struct), \ 433 &(struct kmem_cache_args) { \ 434 .align = __alignof__(struct __struct), \ 435 .useroffset = offsetof(struct __struct, __field), \ 436 .usersize = sizeof_field(struct __struct, __field), \ 437 }, (__flags)) 438 439 /* 440 * Common kmalloc functions provided by all allocators 441 */ 442 void * __must_check krealloc_noprof(const void *objp, size_t new_size, 443 gfp_t flags) __realloc_size(2); 444 #define krealloc(...) alloc_hooks(krealloc_noprof(__VA_ARGS__)) 445 446 void kfree(const void *objp); 447 void kfree_sensitive(const void *objp); 448 size_t __ksize(const void *objp); 449 450 DEFINE_FREE(kfree, void *, if (!IS_ERR_OR_NULL(_T)) kfree(_T)) 451 452 /** 453 * ksize - Report actual allocation size of associated object 454 * 455 * @objp: Pointer returned from a prior kmalloc()-family allocation. 456 * 457 * This should not be used for writing beyond the originally requested 458 * allocation size. Either use krealloc() or round up the allocation size 459 * with kmalloc_size_roundup() prior to allocation. If this is used to 460 * access beyond the originally requested allocation size, UBSAN_BOUNDS 461 * and/or FORTIFY_SOURCE may trip, since they only know about the 462 * originally allocated size via the __alloc_size attribute. 463 */ 464 size_t ksize(const void *objp); 465 466 #ifdef CONFIG_PRINTK 467 bool kmem_dump_obj(void *object); 468 #else 469 static inline bool kmem_dump_obj(void *object) { return false; } 470 #endif 471 472 /* 473 * Some archs want to perform DMA into kmalloc caches and need a guaranteed 474 * alignment larger than the alignment of a 64-bit integer. 475 * Setting ARCH_DMA_MINALIGN in arch headers allows that. 476 */ 477 #ifdef ARCH_HAS_DMA_MINALIGN 478 #if ARCH_DMA_MINALIGN > 8 && !defined(ARCH_KMALLOC_MINALIGN) 479 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN 480 #endif 481 #endif 482 483 #ifndef ARCH_KMALLOC_MINALIGN 484 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) 485 #elif ARCH_KMALLOC_MINALIGN > 8 486 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN 487 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE) 488 #endif 489 490 /* 491 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment. 492 * Intended for arches that get misalignment faults even for 64 bit integer 493 * aligned buffers. 494 */ 495 #ifndef ARCH_SLAB_MINALIGN 496 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long) 497 #endif 498 499 /* 500 * Arches can define this function if they want to decide the minimum slab 501 * alignment at runtime. The value returned by the function must be a power 502 * of two and >= ARCH_SLAB_MINALIGN. 503 */ 504 #ifndef arch_slab_minalign 505 static inline unsigned int arch_slab_minalign(void) 506 { 507 return ARCH_SLAB_MINALIGN; 508 } 509 #endif 510 511 /* 512 * kmem_cache_alloc and friends return pointers aligned to ARCH_SLAB_MINALIGN. 513 * kmalloc and friends return pointers aligned to both ARCH_KMALLOC_MINALIGN 514 * and ARCH_SLAB_MINALIGN, but here we only assume the former alignment. 515 */ 516 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN) 517 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN) 518 #define __assume_page_alignment __assume_aligned(PAGE_SIZE) 519 520 /* 521 * Kmalloc array related definitions 522 */ 523 524 /* 525 * SLUB directly allocates requests fitting in to an order-1 page 526 * (PAGE_SIZE*2). Larger requests are passed to the page allocator. 527 */ 528 #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1) 529 #define KMALLOC_SHIFT_MAX (MAX_PAGE_ORDER + PAGE_SHIFT) 530 #ifndef KMALLOC_SHIFT_LOW 531 #define KMALLOC_SHIFT_LOW 3 532 #endif 533 534 /* Maximum allocatable size */ 535 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX) 536 /* Maximum size for which we actually use a slab cache */ 537 #define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH) 538 /* Maximum order allocatable via the slab allocator */ 539 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT) 540 541 /* 542 * Kmalloc subsystem. 543 */ 544 #ifndef KMALLOC_MIN_SIZE 545 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW) 546 #endif 547 548 /* 549 * This restriction comes from byte sized index implementation. 550 * Page size is normally 2^12 bytes and, in this case, if we want to use 551 * byte sized index which can represent 2^8 entries, the size of the object 552 * should be equal or greater to 2^12 / 2^8 = 2^4 = 16. 553 * If minimum size of kmalloc is less than 16, we use it as minimum object 554 * size and give up to use byte sized index. 555 */ 556 #define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \ 557 (KMALLOC_MIN_SIZE) : 16) 558 559 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 560 #define RANDOM_KMALLOC_CACHES_NR 15 // # of cache copies 561 #else 562 #define RANDOM_KMALLOC_CACHES_NR 0 563 #endif 564 565 /* 566 * Whenever changing this, take care of that kmalloc_type() and 567 * create_kmalloc_caches() still work as intended. 568 * 569 * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP 570 * is for accounted but unreclaimable and non-dma objects. All the other 571 * kmem caches can have both accounted and unaccounted objects. 572 */ 573 enum kmalloc_cache_type { 574 KMALLOC_NORMAL = 0, 575 #ifndef CONFIG_ZONE_DMA 576 KMALLOC_DMA = KMALLOC_NORMAL, 577 #endif 578 #ifndef CONFIG_MEMCG 579 KMALLOC_CGROUP = KMALLOC_NORMAL, 580 #endif 581 KMALLOC_RANDOM_START = KMALLOC_NORMAL, 582 KMALLOC_RANDOM_END = KMALLOC_RANDOM_START + RANDOM_KMALLOC_CACHES_NR, 583 #ifdef CONFIG_SLUB_TINY 584 KMALLOC_RECLAIM = KMALLOC_NORMAL, 585 #else 586 KMALLOC_RECLAIM, 587 #endif 588 #ifdef CONFIG_ZONE_DMA 589 KMALLOC_DMA, 590 #endif 591 #ifdef CONFIG_MEMCG 592 KMALLOC_CGROUP, 593 #endif 594 NR_KMALLOC_TYPES 595 }; 596 597 typedef struct kmem_cache * kmem_buckets[KMALLOC_SHIFT_HIGH + 1]; 598 599 extern kmem_buckets kmalloc_caches[NR_KMALLOC_TYPES]; 600 601 /* 602 * Define gfp bits that should not be set for KMALLOC_NORMAL. 603 */ 604 #define KMALLOC_NOT_NORMAL_BITS \ 605 (__GFP_RECLAIMABLE | \ 606 (IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \ 607 (IS_ENABLED(CONFIG_MEMCG) ? __GFP_ACCOUNT : 0)) 608 609 extern unsigned long random_kmalloc_seed; 610 611 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags, unsigned long caller) 612 { 613 /* 614 * The most common case is KMALLOC_NORMAL, so test for it 615 * with a single branch for all the relevant flags. 616 */ 617 if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0)) 618 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 619 /* RANDOM_KMALLOC_CACHES_NR (=15) copies + the KMALLOC_NORMAL */ 620 return KMALLOC_RANDOM_START + hash_64(caller ^ random_kmalloc_seed, 621 ilog2(RANDOM_KMALLOC_CACHES_NR + 1)); 622 #else 623 return KMALLOC_NORMAL; 624 #endif 625 626 /* 627 * At least one of the flags has to be set. Their priorities in 628 * decreasing order are: 629 * 1) __GFP_DMA 630 * 2) __GFP_RECLAIMABLE 631 * 3) __GFP_ACCOUNT 632 */ 633 if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA)) 634 return KMALLOC_DMA; 635 if (!IS_ENABLED(CONFIG_MEMCG) || (flags & __GFP_RECLAIMABLE)) 636 return KMALLOC_RECLAIM; 637 else 638 return KMALLOC_CGROUP; 639 } 640 641 /* 642 * Figure out which kmalloc slab an allocation of a certain size 643 * belongs to. 644 * 0 = zero alloc 645 * 1 = 65 .. 96 bytes 646 * 2 = 129 .. 192 bytes 647 * n = 2^(n-1)+1 .. 2^n 648 * 649 * Note: __kmalloc_index() is compile-time optimized, and not runtime optimized; 650 * typical usage is via kmalloc_index() and therefore evaluated at compile-time. 651 * Callers where !size_is_constant should only be test modules, where runtime 652 * overheads of __kmalloc_index() can be tolerated. Also see kmalloc_slab(). 653 */ 654 static __always_inline unsigned int __kmalloc_index(size_t size, 655 bool size_is_constant) 656 { 657 if (!size) 658 return 0; 659 660 if (size <= KMALLOC_MIN_SIZE) 661 return KMALLOC_SHIFT_LOW; 662 663 if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96) 664 return 1; 665 if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192) 666 return 2; 667 if (size <= 8) return 3; 668 if (size <= 16) return 4; 669 if (size <= 32) return 5; 670 if (size <= 64) return 6; 671 if (size <= 128) return 7; 672 if (size <= 256) return 8; 673 if (size <= 512) return 9; 674 if (size <= 1024) return 10; 675 if (size <= 2 * 1024) return 11; 676 if (size <= 4 * 1024) return 12; 677 if (size <= 8 * 1024) return 13; 678 if (size <= 16 * 1024) return 14; 679 if (size <= 32 * 1024) return 15; 680 if (size <= 64 * 1024) return 16; 681 if (size <= 128 * 1024) return 17; 682 if (size <= 256 * 1024) return 18; 683 if (size <= 512 * 1024) return 19; 684 if (size <= 1024 * 1024) return 20; 685 if (size <= 2 * 1024 * 1024) return 21; 686 687 if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant) 688 BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()"); 689 else 690 BUG(); 691 692 /* Will never be reached. Needed because the compiler may complain */ 693 return -1; 694 } 695 static_assert(PAGE_SHIFT <= 20); 696 #define kmalloc_index(s) __kmalloc_index(s, true) 697 698 #include <linux/alloc_tag.h> 699 700 /** 701 * kmem_cache_alloc - Allocate an object 702 * @cachep: The cache to allocate from. 703 * @flags: See kmalloc(). 704 * 705 * Allocate an object from this cache. 706 * See kmem_cache_zalloc() for a shortcut of adding __GFP_ZERO to flags. 707 * 708 * Return: pointer to the new object or %NULL in case of error 709 */ 710 void *kmem_cache_alloc_noprof(struct kmem_cache *cachep, 711 gfp_t flags) __assume_slab_alignment __malloc; 712 #define kmem_cache_alloc(...) alloc_hooks(kmem_cache_alloc_noprof(__VA_ARGS__)) 713 714 void *kmem_cache_alloc_lru_noprof(struct kmem_cache *s, struct list_lru *lru, 715 gfp_t gfpflags) __assume_slab_alignment __malloc; 716 #define kmem_cache_alloc_lru(...) alloc_hooks(kmem_cache_alloc_lru_noprof(__VA_ARGS__)) 717 718 void kmem_cache_free(struct kmem_cache *s, void *objp); 719 720 kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, 721 unsigned int useroffset, unsigned int usersize, 722 void (*ctor)(void *)); 723 724 /* 725 * Bulk allocation and freeing operations. These are accelerated in an 726 * allocator specific way to avoid taking locks repeatedly or building 727 * metadata structures unnecessarily. 728 * 729 * Note that interrupts must be enabled when calling these functions. 730 */ 731 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p); 732 733 int kmem_cache_alloc_bulk_noprof(struct kmem_cache *s, gfp_t flags, size_t size, void **p); 734 #define kmem_cache_alloc_bulk(...) alloc_hooks(kmem_cache_alloc_bulk_noprof(__VA_ARGS__)) 735 736 static __always_inline void kfree_bulk(size_t size, void **p) 737 { 738 kmem_cache_free_bulk(NULL, size, p); 739 } 740 741 void *kmem_cache_alloc_node_noprof(struct kmem_cache *s, gfp_t flags, 742 int node) __assume_slab_alignment __malloc; 743 #define kmem_cache_alloc_node(...) alloc_hooks(kmem_cache_alloc_node_noprof(__VA_ARGS__)) 744 745 /* 746 * These macros allow declaring a kmem_buckets * parameter alongside size, which 747 * can be compiled out with CONFIG_SLAB_BUCKETS=n so that a large number of call 748 * sites don't have to pass NULL. 749 */ 750 #ifdef CONFIG_SLAB_BUCKETS 751 #define DECL_BUCKET_PARAMS(_size, _b) size_t (_size), kmem_buckets *(_b) 752 #define PASS_BUCKET_PARAMS(_size, _b) (_size), (_b) 753 #define PASS_BUCKET_PARAM(_b) (_b) 754 #else 755 #define DECL_BUCKET_PARAMS(_size, _b) size_t (_size) 756 #define PASS_BUCKET_PARAMS(_size, _b) (_size) 757 #define PASS_BUCKET_PARAM(_b) NULL 758 #endif 759 760 /* 761 * The following functions are not to be used directly and are intended only 762 * for internal use from kmalloc() and kmalloc_node() 763 * with the exception of kunit tests 764 */ 765 766 void *__kmalloc_noprof(size_t size, gfp_t flags) 767 __assume_kmalloc_alignment __alloc_size(1); 768 769 void *__kmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node) 770 __assume_kmalloc_alignment __alloc_size(1); 771 772 void *__kmalloc_cache_noprof(struct kmem_cache *s, gfp_t flags, size_t size) 773 __assume_kmalloc_alignment __alloc_size(3); 774 775 void *__kmalloc_cache_node_noprof(struct kmem_cache *s, gfp_t gfpflags, 776 int node, size_t size) 777 __assume_kmalloc_alignment __alloc_size(4); 778 779 void *__kmalloc_large_noprof(size_t size, gfp_t flags) 780 __assume_page_alignment __alloc_size(1); 781 782 void *__kmalloc_large_node_noprof(size_t size, gfp_t flags, int node) 783 __assume_page_alignment __alloc_size(1); 784 785 /** 786 * kmalloc - allocate kernel memory 787 * @size: how many bytes of memory are required. 788 * @flags: describe the allocation context 789 * 790 * kmalloc is the normal method of allocating memory 791 * for objects smaller than page size in the kernel. 792 * 793 * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN 794 * bytes. For @size of power of two bytes, the alignment is also guaranteed 795 * to be at least to the size. For other sizes, the alignment is guaranteed to 796 * be at least the largest power-of-two divisor of @size. 797 * 798 * The @flags argument may be one of the GFP flags defined at 799 * include/linux/gfp_types.h and described at 800 * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>` 801 * 802 * The recommended usage of the @flags is described at 803 * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>` 804 * 805 * Below is a brief outline of the most useful GFP flags 806 * 807 * %GFP_KERNEL 808 * Allocate normal kernel ram. May sleep. 809 * 810 * %GFP_NOWAIT 811 * Allocation will not sleep. 812 * 813 * %GFP_ATOMIC 814 * Allocation will not sleep. May use emergency pools. 815 * 816 * Also it is possible to set different flags by OR'ing 817 * in one or more of the following additional @flags: 818 * 819 * %__GFP_ZERO 820 * Zero the allocated memory before returning. Also see kzalloc(). 821 * 822 * %__GFP_HIGH 823 * This allocation has high priority and may use emergency pools. 824 * 825 * %__GFP_NOFAIL 826 * Indicate that this allocation is in no way allowed to fail 827 * (think twice before using). 828 * 829 * %__GFP_NORETRY 830 * If memory is not immediately available, 831 * then give up at once. 832 * 833 * %__GFP_NOWARN 834 * If allocation fails, don't issue any warnings. 835 * 836 * %__GFP_RETRY_MAYFAIL 837 * Try really hard to succeed the allocation but fail 838 * eventually. 839 */ 840 static __always_inline __alloc_size(1) void *kmalloc_noprof(size_t size, gfp_t flags) 841 { 842 if (__builtin_constant_p(size) && size) { 843 unsigned int index; 844 845 if (size > KMALLOC_MAX_CACHE_SIZE) 846 return __kmalloc_large_noprof(size, flags); 847 848 index = kmalloc_index(size); 849 return __kmalloc_cache_noprof( 850 kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index], 851 flags, size); 852 } 853 return __kmalloc_noprof(size, flags); 854 } 855 #define kmalloc(...) alloc_hooks(kmalloc_noprof(__VA_ARGS__)) 856 857 #define kmem_buckets_alloc(_b, _size, _flags) \ 858 alloc_hooks(__kmalloc_node_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE)) 859 860 #define kmem_buckets_alloc_track_caller(_b, _size, _flags) \ 861 alloc_hooks(__kmalloc_node_track_caller_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE, _RET_IP_)) 862 863 static __always_inline __alloc_size(1) void *kmalloc_node_noprof(size_t size, gfp_t flags, int node) 864 { 865 if (__builtin_constant_p(size) && size) { 866 unsigned int index; 867 868 if (size > KMALLOC_MAX_CACHE_SIZE) 869 return __kmalloc_large_node_noprof(size, flags, node); 870 871 index = kmalloc_index(size); 872 return __kmalloc_cache_node_noprof( 873 kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index], 874 flags, node, size); 875 } 876 return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node); 877 } 878 #define kmalloc_node(...) alloc_hooks(kmalloc_node_noprof(__VA_ARGS__)) 879 880 /** 881 * kmalloc_array - allocate memory for an array. 882 * @n: number of elements. 883 * @size: element size. 884 * @flags: the type of memory to allocate (see kmalloc). 885 */ 886 static inline __alloc_size(1, 2) void *kmalloc_array_noprof(size_t n, size_t size, gfp_t flags) 887 { 888 size_t bytes; 889 890 if (unlikely(check_mul_overflow(n, size, &bytes))) 891 return NULL; 892 if (__builtin_constant_p(n) && __builtin_constant_p(size)) 893 return kmalloc_noprof(bytes, flags); 894 return kmalloc_noprof(bytes, flags); 895 } 896 #define kmalloc_array(...) alloc_hooks(kmalloc_array_noprof(__VA_ARGS__)) 897 898 /** 899 * krealloc_array - reallocate memory for an array. 900 * @p: pointer to the memory chunk to reallocate 901 * @new_n: new number of elements to alloc 902 * @new_size: new size of a single member of the array 903 * @flags: the type of memory to allocate (see kmalloc) 904 */ 905 static inline __realloc_size(2, 3) void * __must_check krealloc_array_noprof(void *p, 906 size_t new_n, 907 size_t new_size, 908 gfp_t flags) 909 { 910 size_t bytes; 911 912 if (unlikely(check_mul_overflow(new_n, new_size, &bytes))) 913 return NULL; 914 915 return krealloc_noprof(p, bytes, flags); 916 } 917 #define krealloc_array(...) alloc_hooks(krealloc_array_noprof(__VA_ARGS__)) 918 919 /** 920 * kcalloc - allocate memory for an array. The memory is set to zero. 921 * @n: number of elements. 922 * @size: element size. 923 * @flags: the type of memory to allocate (see kmalloc). 924 */ 925 #define kcalloc(n, size, flags) kmalloc_array(n, size, (flags) | __GFP_ZERO) 926 927 void *__kmalloc_node_track_caller_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node, 928 unsigned long caller) __alloc_size(1); 929 #define kmalloc_node_track_caller_noprof(size, flags, node, caller) \ 930 __kmalloc_node_track_caller_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node, caller) 931 #define kmalloc_node_track_caller(...) \ 932 alloc_hooks(kmalloc_node_track_caller_noprof(__VA_ARGS__, _RET_IP_)) 933 934 /* 935 * kmalloc_track_caller is a special version of kmalloc that records the 936 * calling function of the routine calling it for slab leak tracking instead 937 * of just the calling function (confusing, eh?). 938 * It's useful when the call to kmalloc comes from a widely-used standard 939 * allocator where we care about the real place the memory allocation 940 * request comes from. 941 */ 942 #define kmalloc_track_caller(...) kmalloc_node_track_caller(__VA_ARGS__, NUMA_NO_NODE) 943 944 #define kmalloc_track_caller_noprof(...) \ 945 kmalloc_node_track_caller_noprof(__VA_ARGS__, NUMA_NO_NODE, _RET_IP_) 946 947 static inline __alloc_size(1, 2) void *kmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, 948 int node) 949 { 950 size_t bytes; 951 952 if (unlikely(check_mul_overflow(n, size, &bytes))) 953 return NULL; 954 if (__builtin_constant_p(n) && __builtin_constant_p(size)) 955 return kmalloc_node_noprof(bytes, flags, node); 956 return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(bytes, NULL), flags, node); 957 } 958 #define kmalloc_array_node(...) alloc_hooks(kmalloc_array_node_noprof(__VA_ARGS__)) 959 960 #define kcalloc_node(_n, _size, _flags, _node) \ 961 kmalloc_array_node(_n, _size, (_flags) | __GFP_ZERO, _node) 962 963 /* 964 * Shortcuts 965 */ 966 #define kmem_cache_zalloc(_k, _flags) kmem_cache_alloc(_k, (_flags)|__GFP_ZERO) 967 968 /** 969 * kzalloc - allocate memory. The memory is set to zero. 970 * @size: how many bytes of memory are required. 971 * @flags: the type of memory to allocate (see kmalloc). 972 */ 973 static inline __alloc_size(1) void *kzalloc_noprof(size_t size, gfp_t flags) 974 { 975 return kmalloc_noprof(size, flags | __GFP_ZERO); 976 } 977 #define kzalloc(...) alloc_hooks(kzalloc_noprof(__VA_ARGS__)) 978 #define kzalloc_node(_size, _flags, _node) kmalloc_node(_size, (_flags)|__GFP_ZERO, _node) 979 980 void *__kvmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node) __alloc_size(1); 981 #define kvmalloc_node_noprof(size, flags, node) \ 982 __kvmalloc_node_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node) 983 #define kvmalloc_node(...) alloc_hooks(kvmalloc_node_noprof(__VA_ARGS__)) 984 985 #define kvmalloc(_size, _flags) kvmalloc_node(_size, _flags, NUMA_NO_NODE) 986 #define kvmalloc_noprof(_size, _flags) kvmalloc_node_noprof(_size, _flags, NUMA_NO_NODE) 987 #define kvzalloc(_size, _flags) kvmalloc(_size, (_flags)|__GFP_ZERO) 988 989 #define kvzalloc_node(_size, _flags, _node) kvmalloc_node(_size, (_flags)|__GFP_ZERO, _node) 990 #define kmem_buckets_valloc(_b, _size, _flags) \ 991 alloc_hooks(__kvmalloc_node_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE)) 992 993 static inline __alloc_size(1, 2) void * 994 kvmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, int node) 995 { 996 size_t bytes; 997 998 if (unlikely(check_mul_overflow(n, size, &bytes))) 999 return NULL; 1000 1001 return kvmalloc_node_noprof(bytes, flags, node); 1002 } 1003 1004 #define kvmalloc_array_noprof(...) kvmalloc_array_node_noprof(__VA_ARGS__, NUMA_NO_NODE) 1005 #define kvcalloc_node_noprof(_n,_s,_f,_node) kvmalloc_array_node_noprof(_n,_s,(_f)|__GFP_ZERO,_node) 1006 #define kvcalloc_noprof(...) kvcalloc_node_noprof(__VA_ARGS__, NUMA_NO_NODE) 1007 1008 #define kvmalloc_array(...) alloc_hooks(kvmalloc_array_noprof(__VA_ARGS__)) 1009 #define kvcalloc_node(...) alloc_hooks(kvcalloc_node_noprof(__VA_ARGS__)) 1010 #define kvcalloc(...) alloc_hooks(kvcalloc_noprof(__VA_ARGS__)) 1011 1012 extern void *kvrealloc_noprof(const void *p, size_t oldsize, size_t newsize, gfp_t flags) 1013 __realloc_size(3); 1014 #define kvrealloc(...) alloc_hooks(kvrealloc_noprof(__VA_ARGS__)) 1015 1016 extern void kvfree(const void *addr); 1017 DEFINE_FREE(kvfree, void *, if (!IS_ERR_OR_NULL(_T)) kvfree(_T)) 1018 1019 extern void kvfree_sensitive(const void *addr, size_t len); 1020 1021 unsigned int kmem_cache_size(struct kmem_cache *s); 1022 1023 /** 1024 * kmalloc_size_roundup - Report allocation bucket size for the given size 1025 * 1026 * @size: Number of bytes to round up from. 1027 * 1028 * This returns the number of bytes that would be available in a kmalloc() 1029 * allocation of @size bytes. For example, a 126 byte request would be 1030 * rounded up to the next sized kmalloc bucket, 128 bytes. (This is strictly 1031 * for the general-purpose kmalloc()-based allocations, and is not for the 1032 * pre-sized kmem_cache_alloc()-based allocations.) 1033 * 1034 * Use this to kmalloc() the full bucket size ahead of time instead of using 1035 * ksize() to query the size after an allocation. 1036 */ 1037 size_t kmalloc_size_roundup(size_t size); 1038 1039 void __init kmem_cache_init_late(void); 1040 1041 #endif /* _LINUX_SLAB_H */ 1042