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 struct kmem_cache *kmem_cache_create(const char *name, unsigned int size, 244 unsigned int align, slab_flags_t flags, 245 void (*ctor)(void *)); 246 struct kmem_cache *kmem_cache_create_usercopy(const char *name, 247 unsigned int size, unsigned int align, 248 slab_flags_t flags, 249 unsigned int useroffset, unsigned int usersize, 250 void (*ctor)(void *)); 251 struct kmem_cache *kmem_cache_create_rcu(const char *name, unsigned int size, 252 unsigned int freeptr_offset, 253 slab_flags_t flags); 254 void kmem_cache_destroy(struct kmem_cache *s); 255 int kmem_cache_shrink(struct kmem_cache *s); 256 257 /* 258 * Please use this macro to create slab caches. Simply specify the 259 * name of the structure and maybe some flags that are listed above. 260 * 261 * The alignment of the struct determines object alignment. If you 262 * f.e. add ____cacheline_aligned_in_smp to the struct declaration 263 * then the objects will be properly aligned in SMP configurations. 264 */ 265 #define KMEM_CACHE(__struct, __flags) \ 266 kmem_cache_create(#__struct, sizeof(struct __struct), \ 267 __alignof__(struct __struct), (__flags), NULL) 268 269 /* 270 * To whitelist a single field for copying to/from usercopy, use this 271 * macro instead for KMEM_CACHE() above. 272 */ 273 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \ 274 kmem_cache_create_usercopy(#__struct, \ 275 sizeof(struct __struct), \ 276 __alignof__(struct __struct), (__flags), \ 277 offsetof(struct __struct, __field), \ 278 sizeof_field(struct __struct, __field), NULL) 279 280 /* 281 * Common kmalloc functions provided by all allocators 282 */ 283 void * __must_check krealloc_noprof(const void *objp, size_t new_size, 284 gfp_t flags) __realloc_size(2); 285 #define krealloc(...) alloc_hooks(krealloc_noprof(__VA_ARGS__)) 286 287 void kfree(const void *objp); 288 void kfree_sensitive(const void *objp); 289 size_t __ksize(const void *objp); 290 291 DEFINE_FREE(kfree, void *, if (!IS_ERR_OR_NULL(_T)) kfree(_T)) 292 293 /** 294 * ksize - Report actual allocation size of associated object 295 * 296 * @objp: Pointer returned from a prior kmalloc()-family allocation. 297 * 298 * This should not be used for writing beyond the originally requested 299 * allocation size. Either use krealloc() or round up the allocation size 300 * with kmalloc_size_roundup() prior to allocation. If this is used to 301 * access beyond the originally requested allocation size, UBSAN_BOUNDS 302 * and/or FORTIFY_SOURCE may trip, since they only know about the 303 * originally allocated size via the __alloc_size attribute. 304 */ 305 size_t ksize(const void *objp); 306 307 #ifdef CONFIG_PRINTK 308 bool kmem_dump_obj(void *object); 309 #else 310 static inline bool kmem_dump_obj(void *object) { return false; } 311 #endif 312 313 /* 314 * Some archs want to perform DMA into kmalloc caches and need a guaranteed 315 * alignment larger than the alignment of a 64-bit integer. 316 * Setting ARCH_DMA_MINALIGN in arch headers allows that. 317 */ 318 #ifdef ARCH_HAS_DMA_MINALIGN 319 #if ARCH_DMA_MINALIGN > 8 && !defined(ARCH_KMALLOC_MINALIGN) 320 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN 321 #endif 322 #endif 323 324 #ifndef ARCH_KMALLOC_MINALIGN 325 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) 326 #elif ARCH_KMALLOC_MINALIGN > 8 327 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN 328 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE) 329 #endif 330 331 /* 332 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment. 333 * Intended for arches that get misalignment faults even for 64 bit integer 334 * aligned buffers. 335 */ 336 #ifndef ARCH_SLAB_MINALIGN 337 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long) 338 #endif 339 340 /* 341 * Arches can define this function if they want to decide the minimum slab 342 * alignment at runtime. The value returned by the function must be a power 343 * of two and >= ARCH_SLAB_MINALIGN. 344 */ 345 #ifndef arch_slab_minalign 346 static inline unsigned int arch_slab_minalign(void) 347 { 348 return ARCH_SLAB_MINALIGN; 349 } 350 #endif 351 352 /* 353 * kmem_cache_alloc and friends return pointers aligned to ARCH_SLAB_MINALIGN. 354 * kmalloc and friends return pointers aligned to both ARCH_KMALLOC_MINALIGN 355 * and ARCH_SLAB_MINALIGN, but here we only assume the former alignment. 356 */ 357 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN) 358 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN) 359 #define __assume_page_alignment __assume_aligned(PAGE_SIZE) 360 361 /* 362 * Kmalloc array related definitions 363 */ 364 365 /* 366 * SLUB directly allocates requests fitting in to an order-1 page 367 * (PAGE_SIZE*2). Larger requests are passed to the page allocator. 368 */ 369 #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1) 370 #define KMALLOC_SHIFT_MAX (MAX_PAGE_ORDER + PAGE_SHIFT) 371 #ifndef KMALLOC_SHIFT_LOW 372 #define KMALLOC_SHIFT_LOW 3 373 #endif 374 375 /* Maximum allocatable size */ 376 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX) 377 /* Maximum size for which we actually use a slab cache */ 378 #define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH) 379 /* Maximum order allocatable via the slab allocator */ 380 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT) 381 382 /* 383 * Kmalloc subsystem. 384 */ 385 #ifndef KMALLOC_MIN_SIZE 386 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW) 387 #endif 388 389 /* 390 * This restriction comes from byte sized index implementation. 391 * Page size is normally 2^12 bytes and, in this case, if we want to use 392 * byte sized index which can represent 2^8 entries, the size of the object 393 * should be equal or greater to 2^12 / 2^8 = 2^4 = 16. 394 * If minimum size of kmalloc is less than 16, we use it as minimum object 395 * size and give up to use byte sized index. 396 */ 397 #define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \ 398 (KMALLOC_MIN_SIZE) : 16) 399 400 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 401 #define RANDOM_KMALLOC_CACHES_NR 15 // # of cache copies 402 #else 403 #define RANDOM_KMALLOC_CACHES_NR 0 404 #endif 405 406 /* 407 * Whenever changing this, take care of that kmalloc_type() and 408 * create_kmalloc_caches() still work as intended. 409 * 410 * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP 411 * is for accounted but unreclaimable and non-dma objects. All the other 412 * kmem caches can have both accounted and unaccounted objects. 413 */ 414 enum kmalloc_cache_type { 415 KMALLOC_NORMAL = 0, 416 #ifndef CONFIG_ZONE_DMA 417 KMALLOC_DMA = KMALLOC_NORMAL, 418 #endif 419 #ifndef CONFIG_MEMCG 420 KMALLOC_CGROUP = KMALLOC_NORMAL, 421 #endif 422 KMALLOC_RANDOM_START = KMALLOC_NORMAL, 423 KMALLOC_RANDOM_END = KMALLOC_RANDOM_START + RANDOM_KMALLOC_CACHES_NR, 424 #ifdef CONFIG_SLUB_TINY 425 KMALLOC_RECLAIM = KMALLOC_NORMAL, 426 #else 427 KMALLOC_RECLAIM, 428 #endif 429 #ifdef CONFIG_ZONE_DMA 430 KMALLOC_DMA, 431 #endif 432 #ifdef CONFIG_MEMCG 433 KMALLOC_CGROUP, 434 #endif 435 NR_KMALLOC_TYPES 436 }; 437 438 typedef struct kmem_cache * kmem_buckets[KMALLOC_SHIFT_HIGH + 1]; 439 440 extern kmem_buckets kmalloc_caches[NR_KMALLOC_TYPES]; 441 442 /* 443 * Define gfp bits that should not be set for KMALLOC_NORMAL. 444 */ 445 #define KMALLOC_NOT_NORMAL_BITS \ 446 (__GFP_RECLAIMABLE | \ 447 (IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \ 448 (IS_ENABLED(CONFIG_MEMCG) ? __GFP_ACCOUNT : 0)) 449 450 extern unsigned long random_kmalloc_seed; 451 452 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags, unsigned long caller) 453 { 454 /* 455 * The most common case is KMALLOC_NORMAL, so test for it 456 * with a single branch for all the relevant flags. 457 */ 458 if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0)) 459 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 460 /* RANDOM_KMALLOC_CACHES_NR (=15) copies + the KMALLOC_NORMAL */ 461 return KMALLOC_RANDOM_START + hash_64(caller ^ random_kmalloc_seed, 462 ilog2(RANDOM_KMALLOC_CACHES_NR + 1)); 463 #else 464 return KMALLOC_NORMAL; 465 #endif 466 467 /* 468 * At least one of the flags has to be set. Their priorities in 469 * decreasing order are: 470 * 1) __GFP_DMA 471 * 2) __GFP_RECLAIMABLE 472 * 3) __GFP_ACCOUNT 473 */ 474 if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA)) 475 return KMALLOC_DMA; 476 if (!IS_ENABLED(CONFIG_MEMCG) || (flags & __GFP_RECLAIMABLE)) 477 return KMALLOC_RECLAIM; 478 else 479 return KMALLOC_CGROUP; 480 } 481 482 /* 483 * Figure out which kmalloc slab an allocation of a certain size 484 * belongs to. 485 * 0 = zero alloc 486 * 1 = 65 .. 96 bytes 487 * 2 = 129 .. 192 bytes 488 * n = 2^(n-1)+1 .. 2^n 489 * 490 * Note: __kmalloc_index() is compile-time optimized, and not runtime optimized; 491 * typical usage is via kmalloc_index() and therefore evaluated at compile-time. 492 * Callers where !size_is_constant should only be test modules, where runtime 493 * overheads of __kmalloc_index() can be tolerated. Also see kmalloc_slab(). 494 */ 495 static __always_inline unsigned int __kmalloc_index(size_t size, 496 bool size_is_constant) 497 { 498 if (!size) 499 return 0; 500 501 if (size <= KMALLOC_MIN_SIZE) 502 return KMALLOC_SHIFT_LOW; 503 504 if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96) 505 return 1; 506 if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192) 507 return 2; 508 if (size <= 8) return 3; 509 if (size <= 16) return 4; 510 if (size <= 32) return 5; 511 if (size <= 64) return 6; 512 if (size <= 128) return 7; 513 if (size <= 256) return 8; 514 if (size <= 512) return 9; 515 if (size <= 1024) return 10; 516 if (size <= 2 * 1024) return 11; 517 if (size <= 4 * 1024) return 12; 518 if (size <= 8 * 1024) return 13; 519 if (size <= 16 * 1024) return 14; 520 if (size <= 32 * 1024) return 15; 521 if (size <= 64 * 1024) return 16; 522 if (size <= 128 * 1024) return 17; 523 if (size <= 256 * 1024) return 18; 524 if (size <= 512 * 1024) return 19; 525 if (size <= 1024 * 1024) return 20; 526 if (size <= 2 * 1024 * 1024) return 21; 527 528 if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant) 529 BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()"); 530 else 531 BUG(); 532 533 /* Will never be reached. Needed because the compiler may complain */ 534 return -1; 535 } 536 static_assert(PAGE_SHIFT <= 20); 537 #define kmalloc_index(s) __kmalloc_index(s, true) 538 539 #include <linux/alloc_tag.h> 540 541 /** 542 * kmem_cache_alloc - Allocate an object 543 * @cachep: The cache to allocate from. 544 * @flags: See kmalloc(). 545 * 546 * Allocate an object from this cache. 547 * See kmem_cache_zalloc() for a shortcut of adding __GFP_ZERO to flags. 548 * 549 * Return: pointer to the new object or %NULL in case of error 550 */ 551 void *kmem_cache_alloc_noprof(struct kmem_cache *cachep, 552 gfp_t flags) __assume_slab_alignment __malloc; 553 #define kmem_cache_alloc(...) alloc_hooks(kmem_cache_alloc_noprof(__VA_ARGS__)) 554 555 void *kmem_cache_alloc_lru_noprof(struct kmem_cache *s, struct list_lru *lru, 556 gfp_t gfpflags) __assume_slab_alignment __malloc; 557 #define kmem_cache_alloc_lru(...) alloc_hooks(kmem_cache_alloc_lru_noprof(__VA_ARGS__)) 558 559 void kmem_cache_free(struct kmem_cache *s, void *objp); 560 561 kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, 562 unsigned int useroffset, unsigned int usersize, 563 void (*ctor)(void *)); 564 565 /* 566 * Bulk allocation and freeing operations. These are accelerated in an 567 * allocator specific way to avoid taking locks repeatedly or building 568 * metadata structures unnecessarily. 569 * 570 * Note that interrupts must be enabled when calling these functions. 571 */ 572 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p); 573 574 int kmem_cache_alloc_bulk_noprof(struct kmem_cache *s, gfp_t flags, size_t size, void **p); 575 #define kmem_cache_alloc_bulk(...) alloc_hooks(kmem_cache_alloc_bulk_noprof(__VA_ARGS__)) 576 577 static __always_inline void kfree_bulk(size_t size, void **p) 578 { 579 kmem_cache_free_bulk(NULL, size, p); 580 } 581 582 void *kmem_cache_alloc_node_noprof(struct kmem_cache *s, gfp_t flags, 583 int node) __assume_slab_alignment __malloc; 584 #define kmem_cache_alloc_node(...) alloc_hooks(kmem_cache_alloc_node_noprof(__VA_ARGS__)) 585 586 /* 587 * These macros allow declaring a kmem_buckets * parameter alongside size, which 588 * can be compiled out with CONFIG_SLAB_BUCKETS=n so that a large number of call 589 * sites don't have to pass NULL. 590 */ 591 #ifdef CONFIG_SLAB_BUCKETS 592 #define DECL_BUCKET_PARAMS(_size, _b) size_t (_size), kmem_buckets *(_b) 593 #define PASS_BUCKET_PARAMS(_size, _b) (_size), (_b) 594 #define PASS_BUCKET_PARAM(_b) (_b) 595 #else 596 #define DECL_BUCKET_PARAMS(_size, _b) size_t (_size) 597 #define PASS_BUCKET_PARAMS(_size, _b) (_size) 598 #define PASS_BUCKET_PARAM(_b) NULL 599 #endif 600 601 /* 602 * The following functions are not to be used directly and are intended only 603 * for internal use from kmalloc() and kmalloc_node() 604 * with the exception of kunit tests 605 */ 606 607 void *__kmalloc_noprof(size_t size, gfp_t flags) 608 __assume_kmalloc_alignment __alloc_size(1); 609 610 void *__kmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node) 611 __assume_kmalloc_alignment __alloc_size(1); 612 613 void *__kmalloc_cache_noprof(struct kmem_cache *s, gfp_t flags, size_t size) 614 __assume_kmalloc_alignment __alloc_size(3); 615 616 void *__kmalloc_cache_node_noprof(struct kmem_cache *s, gfp_t gfpflags, 617 int node, size_t size) 618 __assume_kmalloc_alignment __alloc_size(4); 619 620 void *__kmalloc_large_noprof(size_t size, gfp_t flags) 621 __assume_page_alignment __alloc_size(1); 622 623 void *__kmalloc_large_node_noprof(size_t size, gfp_t flags, int node) 624 __assume_page_alignment __alloc_size(1); 625 626 /** 627 * kmalloc - allocate kernel memory 628 * @size: how many bytes of memory are required. 629 * @flags: describe the allocation context 630 * 631 * kmalloc is the normal method of allocating memory 632 * for objects smaller than page size in the kernel. 633 * 634 * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN 635 * bytes. For @size of power of two bytes, the alignment is also guaranteed 636 * to be at least to the size. For other sizes, the alignment is guaranteed to 637 * be at least the largest power-of-two divisor of @size. 638 * 639 * The @flags argument may be one of the GFP flags defined at 640 * include/linux/gfp_types.h and described at 641 * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>` 642 * 643 * The recommended usage of the @flags is described at 644 * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>` 645 * 646 * Below is a brief outline of the most useful GFP flags 647 * 648 * %GFP_KERNEL 649 * Allocate normal kernel ram. May sleep. 650 * 651 * %GFP_NOWAIT 652 * Allocation will not sleep. 653 * 654 * %GFP_ATOMIC 655 * Allocation will not sleep. May use emergency pools. 656 * 657 * Also it is possible to set different flags by OR'ing 658 * in one or more of the following additional @flags: 659 * 660 * %__GFP_ZERO 661 * Zero the allocated memory before returning. Also see kzalloc(). 662 * 663 * %__GFP_HIGH 664 * This allocation has high priority and may use emergency pools. 665 * 666 * %__GFP_NOFAIL 667 * Indicate that this allocation is in no way allowed to fail 668 * (think twice before using). 669 * 670 * %__GFP_NORETRY 671 * If memory is not immediately available, 672 * then give up at once. 673 * 674 * %__GFP_NOWARN 675 * If allocation fails, don't issue any warnings. 676 * 677 * %__GFP_RETRY_MAYFAIL 678 * Try really hard to succeed the allocation but fail 679 * eventually. 680 */ 681 static __always_inline __alloc_size(1) void *kmalloc_noprof(size_t size, gfp_t flags) 682 { 683 if (__builtin_constant_p(size) && size) { 684 unsigned int index; 685 686 if (size > KMALLOC_MAX_CACHE_SIZE) 687 return __kmalloc_large_noprof(size, flags); 688 689 index = kmalloc_index(size); 690 return __kmalloc_cache_noprof( 691 kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index], 692 flags, size); 693 } 694 return __kmalloc_noprof(size, flags); 695 } 696 #define kmalloc(...) alloc_hooks(kmalloc_noprof(__VA_ARGS__)) 697 698 #define kmem_buckets_alloc(_b, _size, _flags) \ 699 alloc_hooks(__kmalloc_node_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE)) 700 701 #define kmem_buckets_alloc_track_caller(_b, _size, _flags) \ 702 alloc_hooks(__kmalloc_node_track_caller_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE, _RET_IP_)) 703 704 static __always_inline __alloc_size(1) void *kmalloc_node_noprof(size_t size, gfp_t flags, int node) 705 { 706 if (__builtin_constant_p(size) && size) { 707 unsigned int index; 708 709 if (size > KMALLOC_MAX_CACHE_SIZE) 710 return __kmalloc_large_node_noprof(size, flags, node); 711 712 index = kmalloc_index(size); 713 return __kmalloc_cache_node_noprof( 714 kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index], 715 flags, node, size); 716 } 717 return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node); 718 } 719 #define kmalloc_node(...) alloc_hooks(kmalloc_node_noprof(__VA_ARGS__)) 720 721 /** 722 * kmalloc_array - allocate memory for an array. 723 * @n: number of elements. 724 * @size: element size. 725 * @flags: the type of memory to allocate (see kmalloc). 726 */ 727 static inline __alloc_size(1, 2) void *kmalloc_array_noprof(size_t n, size_t size, gfp_t flags) 728 { 729 size_t bytes; 730 731 if (unlikely(check_mul_overflow(n, size, &bytes))) 732 return NULL; 733 if (__builtin_constant_p(n) && __builtin_constant_p(size)) 734 return kmalloc_noprof(bytes, flags); 735 return kmalloc_noprof(bytes, flags); 736 } 737 #define kmalloc_array(...) alloc_hooks(kmalloc_array_noprof(__VA_ARGS__)) 738 739 /** 740 * krealloc_array - reallocate memory for an array. 741 * @p: pointer to the memory chunk to reallocate 742 * @new_n: new number of elements to alloc 743 * @new_size: new size of a single member of the array 744 * @flags: the type of memory to allocate (see kmalloc) 745 */ 746 static inline __realloc_size(2, 3) void * __must_check krealloc_array_noprof(void *p, 747 size_t new_n, 748 size_t new_size, 749 gfp_t flags) 750 { 751 size_t bytes; 752 753 if (unlikely(check_mul_overflow(new_n, new_size, &bytes))) 754 return NULL; 755 756 return krealloc_noprof(p, bytes, flags); 757 } 758 #define krealloc_array(...) alloc_hooks(krealloc_array_noprof(__VA_ARGS__)) 759 760 /** 761 * kcalloc - allocate memory for an array. The memory is set to zero. 762 * @n: number of elements. 763 * @size: element size. 764 * @flags: the type of memory to allocate (see kmalloc). 765 */ 766 #define kcalloc(n, size, flags) kmalloc_array(n, size, (flags) | __GFP_ZERO) 767 768 void *__kmalloc_node_track_caller_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node, 769 unsigned long caller) __alloc_size(1); 770 #define kmalloc_node_track_caller_noprof(size, flags, node, caller) \ 771 __kmalloc_node_track_caller_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node, caller) 772 #define kmalloc_node_track_caller(...) \ 773 alloc_hooks(kmalloc_node_track_caller_noprof(__VA_ARGS__, _RET_IP_)) 774 775 /* 776 * kmalloc_track_caller is a special version of kmalloc that records the 777 * calling function of the routine calling it for slab leak tracking instead 778 * of just the calling function (confusing, eh?). 779 * It's useful when the call to kmalloc comes from a widely-used standard 780 * allocator where we care about the real place the memory allocation 781 * request comes from. 782 */ 783 #define kmalloc_track_caller(...) kmalloc_node_track_caller(__VA_ARGS__, NUMA_NO_NODE) 784 785 #define kmalloc_track_caller_noprof(...) \ 786 kmalloc_node_track_caller_noprof(__VA_ARGS__, NUMA_NO_NODE, _RET_IP_) 787 788 static inline __alloc_size(1, 2) void *kmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, 789 int node) 790 { 791 size_t bytes; 792 793 if (unlikely(check_mul_overflow(n, size, &bytes))) 794 return NULL; 795 if (__builtin_constant_p(n) && __builtin_constant_p(size)) 796 return kmalloc_node_noprof(bytes, flags, node); 797 return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(bytes, NULL), flags, node); 798 } 799 #define kmalloc_array_node(...) alloc_hooks(kmalloc_array_node_noprof(__VA_ARGS__)) 800 801 #define kcalloc_node(_n, _size, _flags, _node) \ 802 kmalloc_array_node(_n, _size, (_flags) | __GFP_ZERO, _node) 803 804 /* 805 * Shortcuts 806 */ 807 #define kmem_cache_zalloc(_k, _flags) kmem_cache_alloc(_k, (_flags)|__GFP_ZERO) 808 809 /** 810 * kzalloc - allocate memory. The memory is set to zero. 811 * @size: how many bytes of memory are required. 812 * @flags: the type of memory to allocate (see kmalloc). 813 */ 814 static inline __alloc_size(1) void *kzalloc_noprof(size_t size, gfp_t flags) 815 { 816 return kmalloc_noprof(size, flags | __GFP_ZERO); 817 } 818 #define kzalloc(...) alloc_hooks(kzalloc_noprof(__VA_ARGS__)) 819 #define kzalloc_node(_size, _flags, _node) kmalloc_node(_size, (_flags)|__GFP_ZERO, _node) 820 821 void *__kvmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node) __alloc_size(1); 822 #define kvmalloc_node_noprof(size, flags, node) \ 823 __kvmalloc_node_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node) 824 #define kvmalloc_node(...) alloc_hooks(kvmalloc_node_noprof(__VA_ARGS__)) 825 826 #define kvmalloc(_size, _flags) kvmalloc_node(_size, _flags, NUMA_NO_NODE) 827 #define kvmalloc_noprof(_size, _flags) kvmalloc_node_noprof(_size, _flags, NUMA_NO_NODE) 828 #define kvzalloc(_size, _flags) kvmalloc(_size, (_flags)|__GFP_ZERO) 829 830 #define kvzalloc_node(_size, _flags, _node) kvmalloc_node(_size, (_flags)|__GFP_ZERO, _node) 831 #define kmem_buckets_valloc(_b, _size, _flags) \ 832 alloc_hooks(__kvmalloc_node_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE)) 833 834 static inline __alloc_size(1, 2) void * 835 kvmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, int node) 836 { 837 size_t bytes; 838 839 if (unlikely(check_mul_overflow(n, size, &bytes))) 840 return NULL; 841 842 return kvmalloc_node_noprof(bytes, flags, node); 843 } 844 845 #define kvmalloc_array_noprof(...) kvmalloc_array_node_noprof(__VA_ARGS__, NUMA_NO_NODE) 846 #define kvcalloc_node_noprof(_n,_s,_f,_node) kvmalloc_array_node_noprof(_n,_s,(_f)|__GFP_ZERO,_node) 847 #define kvcalloc_noprof(...) kvcalloc_node_noprof(__VA_ARGS__, NUMA_NO_NODE) 848 849 #define kvmalloc_array(...) alloc_hooks(kvmalloc_array_noprof(__VA_ARGS__)) 850 #define kvcalloc_node(...) alloc_hooks(kvcalloc_node_noprof(__VA_ARGS__)) 851 #define kvcalloc(...) alloc_hooks(kvcalloc_noprof(__VA_ARGS__)) 852 853 extern void *kvrealloc_noprof(const void *p, size_t oldsize, size_t newsize, gfp_t flags) 854 __realloc_size(3); 855 #define kvrealloc(...) alloc_hooks(kvrealloc_noprof(__VA_ARGS__)) 856 857 extern void kvfree(const void *addr); 858 DEFINE_FREE(kvfree, void *, if (!IS_ERR_OR_NULL(_T)) kvfree(_T)) 859 860 extern void kvfree_sensitive(const void *addr, size_t len); 861 862 unsigned int kmem_cache_size(struct kmem_cache *s); 863 864 /** 865 * kmalloc_size_roundup - Report allocation bucket size for the given size 866 * 867 * @size: Number of bytes to round up from. 868 * 869 * This returns the number of bytes that would be available in a kmalloc() 870 * allocation of @size bytes. For example, a 126 byte request would be 871 * rounded up to the next sized kmalloc bucket, 128 bytes. (This is strictly 872 * for the general-purpose kmalloc()-based allocations, and is not for the 873 * pre-sized kmem_cache_alloc()-based allocations.) 874 * 875 * Use this to kmalloc() the full bucket size ahead of time instead of using 876 * ksize() to query the size after an allocation. 877 */ 878 size_t kmalloc_size_roundup(size_t size); 879 880 void __init kmem_cache_init_late(void); 881 882 #endif /* _LINUX_SLAB_H */ 883