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 * @align: The required alignment for the objects. 246 * @useroffset: Usercopy region offset 247 * @usersize: Usercopy region size 248 * @freeptr_offset: Custom offset for the free pointer in RCU caches 249 * @use_freeptr_offset: Whether a @freeptr_offset is used 250 * @ctor: A constructor for the objects. 251 */ 252 struct kmem_cache_args { 253 unsigned int align; 254 unsigned int useroffset; 255 unsigned int usersize; 256 unsigned int freeptr_offset; 257 bool use_freeptr_offset; 258 void (*ctor)(void *); 259 }; 260 261 struct kmem_cache *__kmem_cache_create_args(const char *name, 262 unsigned int object_size, 263 struct kmem_cache_args *args, 264 slab_flags_t flags); 265 struct kmem_cache *kmem_cache_create(const char *name, unsigned int size, 266 unsigned int align, slab_flags_t flags, 267 void (*ctor)(void *)); 268 struct kmem_cache *kmem_cache_create_usercopy(const char *name, 269 unsigned int size, unsigned int align, 270 slab_flags_t flags, 271 unsigned int useroffset, unsigned int usersize, 272 void (*ctor)(void *)); 273 struct kmem_cache *kmem_cache_create_rcu(const char *name, unsigned int size, 274 unsigned int freeptr_offset, 275 slab_flags_t flags); 276 void kmem_cache_destroy(struct kmem_cache *s); 277 int kmem_cache_shrink(struct kmem_cache *s); 278 279 /* 280 * Please use this macro to create slab caches. Simply specify the 281 * name of the structure and maybe some flags that are listed above. 282 * 283 * The alignment of the struct determines object alignment. If you 284 * f.e. add ____cacheline_aligned_in_smp to the struct declaration 285 * then the objects will be properly aligned in SMP configurations. 286 */ 287 #define KMEM_CACHE(__struct, __flags) \ 288 __kmem_cache_create_args(#__struct, sizeof(struct __struct), \ 289 &(struct kmem_cache_args) { \ 290 .align = __alignof__(struct __struct), \ 291 }, (__flags)) 292 293 /* 294 * To whitelist a single field for copying to/from usercopy, use this 295 * macro instead for KMEM_CACHE() above. 296 */ 297 #define KMEM_CACHE_USERCOPY(__struct, __flags, __field) \ 298 kmem_cache_create_usercopy(#__struct, \ 299 sizeof(struct __struct), \ 300 __alignof__(struct __struct), (__flags), \ 301 offsetof(struct __struct, __field), \ 302 sizeof_field(struct __struct, __field), NULL) 303 304 /* 305 * Common kmalloc functions provided by all allocators 306 */ 307 void * __must_check krealloc_noprof(const void *objp, size_t new_size, 308 gfp_t flags) __realloc_size(2); 309 #define krealloc(...) alloc_hooks(krealloc_noprof(__VA_ARGS__)) 310 311 void kfree(const void *objp); 312 void kfree_sensitive(const void *objp); 313 size_t __ksize(const void *objp); 314 315 DEFINE_FREE(kfree, void *, if (!IS_ERR_OR_NULL(_T)) kfree(_T)) 316 317 /** 318 * ksize - Report actual allocation size of associated object 319 * 320 * @objp: Pointer returned from a prior kmalloc()-family allocation. 321 * 322 * This should not be used for writing beyond the originally requested 323 * allocation size. Either use krealloc() or round up the allocation size 324 * with kmalloc_size_roundup() prior to allocation. If this is used to 325 * access beyond the originally requested allocation size, UBSAN_BOUNDS 326 * and/or FORTIFY_SOURCE may trip, since they only know about the 327 * originally allocated size via the __alloc_size attribute. 328 */ 329 size_t ksize(const void *objp); 330 331 #ifdef CONFIG_PRINTK 332 bool kmem_dump_obj(void *object); 333 #else 334 static inline bool kmem_dump_obj(void *object) { return false; } 335 #endif 336 337 /* 338 * Some archs want to perform DMA into kmalloc caches and need a guaranteed 339 * alignment larger than the alignment of a 64-bit integer. 340 * Setting ARCH_DMA_MINALIGN in arch headers allows that. 341 */ 342 #ifdef ARCH_HAS_DMA_MINALIGN 343 #if ARCH_DMA_MINALIGN > 8 && !defined(ARCH_KMALLOC_MINALIGN) 344 #define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN 345 #endif 346 #endif 347 348 #ifndef ARCH_KMALLOC_MINALIGN 349 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long) 350 #elif ARCH_KMALLOC_MINALIGN > 8 351 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN 352 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE) 353 #endif 354 355 /* 356 * Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment. 357 * Intended for arches that get misalignment faults even for 64 bit integer 358 * aligned buffers. 359 */ 360 #ifndef ARCH_SLAB_MINALIGN 361 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long) 362 #endif 363 364 /* 365 * Arches can define this function if they want to decide the minimum slab 366 * alignment at runtime. The value returned by the function must be a power 367 * of two and >= ARCH_SLAB_MINALIGN. 368 */ 369 #ifndef arch_slab_minalign 370 static inline unsigned int arch_slab_minalign(void) 371 { 372 return ARCH_SLAB_MINALIGN; 373 } 374 #endif 375 376 /* 377 * kmem_cache_alloc and friends return pointers aligned to ARCH_SLAB_MINALIGN. 378 * kmalloc and friends return pointers aligned to both ARCH_KMALLOC_MINALIGN 379 * and ARCH_SLAB_MINALIGN, but here we only assume the former alignment. 380 */ 381 #define __assume_kmalloc_alignment __assume_aligned(ARCH_KMALLOC_MINALIGN) 382 #define __assume_slab_alignment __assume_aligned(ARCH_SLAB_MINALIGN) 383 #define __assume_page_alignment __assume_aligned(PAGE_SIZE) 384 385 /* 386 * Kmalloc array related definitions 387 */ 388 389 /* 390 * SLUB directly allocates requests fitting in to an order-1 page 391 * (PAGE_SIZE*2). Larger requests are passed to the page allocator. 392 */ 393 #define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1) 394 #define KMALLOC_SHIFT_MAX (MAX_PAGE_ORDER + PAGE_SHIFT) 395 #ifndef KMALLOC_SHIFT_LOW 396 #define KMALLOC_SHIFT_LOW 3 397 #endif 398 399 /* Maximum allocatable size */ 400 #define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX) 401 /* Maximum size for which we actually use a slab cache */ 402 #define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH) 403 /* Maximum order allocatable via the slab allocator */ 404 #define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT) 405 406 /* 407 * Kmalloc subsystem. 408 */ 409 #ifndef KMALLOC_MIN_SIZE 410 #define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW) 411 #endif 412 413 /* 414 * This restriction comes from byte sized index implementation. 415 * Page size is normally 2^12 bytes and, in this case, if we want to use 416 * byte sized index which can represent 2^8 entries, the size of the object 417 * should be equal or greater to 2^12 / 2^8 = 2^4 = 16. 418 * If minimum size of kmalloc is less than 16, we use it as minimum object 419 * size and give up to use byte sized index. 420 */ 421 #define SLAB_OBJ_MIN_SIZE (KMALLOC_MIN_SIZE < 16 ? \ 422 (KMALLOC_MIN_SIZE) : 16) 423 424 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 425 #define RANDOM_KMALLOC_CACHES_NR 15 // # of cache copies 426 #else 427 #define RANDOM_KMALLOC_CACHES_NR 0 428 #endif 429 430 /* 431 * Whenever changing this, take care of that kmalloc_type() and 432 * create_kmalloc_caches() still work as intended. 433 * 434 * KMALLOC_NORMAL can contain only unaccounted objects whereas KMALLOC_CGROUP 435 * is for accounted but unreclaimable and non-dma objects. All the other 436 * kmem caches can have both accounted and unaccounted objects. 437 */ 438 enum kmalloc_cache_type { 439 KMALLOC_NORMAL = 0, 440 #ifndef CONFIG_ZONE_DMA 441 KMALLOC_DMA = KMALLOC_NORMAL, 442 #endif 443 #ifndef CONFIG_MEMCG 444 KMALLOC_CGROUP = KMALLOC_NORMAL, 445 #endif 446 KMALLOC_RANDOM_START = KMALLOC_NORMAL, 447 KMALLOC_RANDOM_END = KMALLOC_RANDOM_START + RANDOM_KMALLOC_CACHES_NR, 448 #ifdef CONFIG_SLUB_TINY 449 KMALLOC_RECLAIM = KMALLOC_NORMAL, 450 #else 451 KMALLOC_RECLAIM, 452 #endif 453 #ifdef CONFIG_ZONE_DMA 454 KMALLOC_DMA, 455 #endif 456 #ifdef CONFIG_MEMCG 457 KMALLOC_CGROUP, 458 #endif 459 NR_KMALLOC_TYPES 460 }; 461 462 typedef struct kmem_cache * kmem_buckets[KMALLOC_SHIFT_HIGH + 1]; 463 464 extern kmem_buckets kmalloc_caches[NR_KMALLOC_TYPES]; 465 466 /* 467 * Define gfp bits that should not be set for KMALLOC_NORMAL. 468 */ 469 #define KMALLOC_NOT_NORMAL_BITS \ 470 (__GFP_RECLAIMABLE | \ 471 (IS_ENABLED(CONFIG_ZONE_DMA) ? __GFP_DMA : 0) | \ 472 (IS_ENABLED(CONFIG_MEMCG) ? __GFP_ACCOUNT : 0)) 473 474 extern unsigned long random_kmalloc_seed; 475 476 static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags, unsigned long caller) 477 { 478 /* 479 * The most common case is KMALLOC_NORMAL, so test for it 480 * with a single branch for all the relevant flags. 481 */ 482 if (likely((flags & KMALLOC_NOT_NORMAL_BITS) == 0)) 483 #ifdef CONFIG_RANDOM_KMALLOC_CACHES 484 /* RANDOM_KMALLOC_CACHES_NR (=15) copies + the KMALLOC_NORMAL */ 485 return KMALLOC_RANDOM_START + hash_64(caller ^ random_kmalloc_seed, 486 ilog2(RANDOM_KMALLOC_CACHES_NR + 1)); 487 #else 488 return KMALLOC_NORMAL; 489 #endif 490 491 /* 492 * At least one of the flags has to be set. Their priorities in 493 * decreasing order are: 494 * 1) __GFP_DMA 495 * 2) __GFP_RECLAIMABLE 496 * 3) __GFP_ACCOUNT 497 */ 498 if (IS_ENABLED(CONFIG_ZONE_DMA) && (flags & __GFP_DMA)) 499 return KMALLOC_DMA; 500 if (!IS_ENABLED(CONFIG_MEMCG) || (flags & __GFP_RECLAIMABLE)) 501 return KMALLOC_RECLAIM; 502 else 503 return KMALLOC_CGROUP; 504 } 505 506 /* 507 * Figure out which kmalloc slab an allocation of a certain size 508 * belongs to. 509 * 0 = zero alloc 510 * 1 = 65 .. 96 bytes 511 * 2 = 129 .. 192 bytes 512 * n = 2^(n-1)+1 .. 2^n 513 * 514 * Note: __kmalloc_index() is compile-time optimized, and not runtime optimized; 515 * typical usage is via kmalloc_index() and therefore evaluated at compile-time. 516 * Callers where !size_is_constant should only be test modules, where runtime 517 * overheads of __kmalloc_index() can be tolerated. Also see kmalloc_slab(). 518 */ 519 static __always_inline unsigned int __kmalloc_index(size_t size, 520 bool size_is_constant) 521 { 522 if (!size) 523 return 0; 524 525 if (size <= KMALLOC_MIN_SIZE) 526 return KMALLOC_SHIFT_LOW; 527 528 if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96) 529 return 1; 530 if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192) 531 return 2; 532 if (size <= 8) return 3; 533 if (size <= 16) return 4; 534 if (size <= 32) return 5; 535 if (size <= 64) return 6; 536 if (size <= 128) return 7; 537 if (size <= 256) return 8; 538 if (size <= 512) return 9; 539 if (size <= 1024) return 10; 540 if (size <= 2 * 1024) return 11; 541 if (size <= 4 * 1024) return 12; 542 if (size <= 8 * 1024) return 13; 543 if (size <= 16 * 1024) return 14; 544 if (size <= 32 * 1024) return 15; 545 if (size <= 64 * 1024) return 16; 546 if (size <= 128 * 1024) return 17; 547 if (size <= 256 * 1024) return 18; 548 if (size <= 512 * 1024) return 19; 549 if (size <= 1024 * 1024) return 20; 550 if (size <= 2 * 1024 * 1024) return 21; 551 552 if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES) && size_is_constant) 553 BUILD_BUG_ON_MSG(1, "unexpected size in kmalloc_index()"); 554 else 555 BUG(); 556 557 /* Will never be reached. Needed because the compiler may complain */ 558 return -1; 559 } 560 static_assert(PAGE_SHIFT <= 20); 561 #define kmalloc_index(s) __kmalloc_index(s, true) 562 563 #include <linux/alloc_tag.h> 564 565 /** 566 * kmem_cache_alloc - Allocate an object 567 * @cachep: The cache to allocate from. 568 * @flags: See kmalloc(). 569 * 570 * Allocate an object from this cache. 571 * See kmem_cache_zalloc() for a shortcut of adding __GFP_ZERO to flags. 572 * 573 * Return: pointer to the new object or %NULL in case of error 574 */ 575 void *kmem_cache_alloc_noprof(struct kmem_cache *cachep, 576 gfp_t flags) __assume_slab_alignment __malloc; 577 #define kmem_cache_alloc(...) alloc_hooks(kmem_cache_alloc_noprof(__VA_ARGS__)) 578 579 void *kmem_cache_alloc_lru_noprof(struct kmem_cache *s, struct list_lru *lru, 580 gfp_t gfpflags) __assume_slab_alignment __malloc; 581 #define kmem_cache_alloc_lru(...) alloc_hooks(kmem_cache_alloc_lru_noprof(__VA_ARGS__)) 582 583 void kmem_cache_free(struct kmem_cache *s, void *objp); 584 585 kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags, 586 unsigned int useroffset, unsigned int usersize, 587 void (*ctor)(void *)); 588 589 /* 590 * Bulk allocation and freeing operations. These are accelerated in an 591 * allocator specific way to avoid taking locks repeatedly or building 592 * metadata structures unnecessarily. 593 * 594 * Note that interrupts must be enabled when calling these functions. 595 */ 596 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p); 597 598 int kmem_cache_alloc_bulk_noprof(struct kmem_cache *s, gfp_t flags, size_t size, void **p); 599 #define kmem_cache_alloc_bulk(...) alloc_hooks(kmem_cache_alloc_bulk_noprof(__VA_ARGS__)) 600 601 static __always_inline void kfree_bulk(size_t size, void **p) 602 { 603 kmem_cache_free_bulk(NULL, size, p); 604 } 605 606 void *kmem_cache_alloc_node_noprof(struct kmem_cache *s, gfp_t flags, 607 int node) __assume_slab_alignment __malloc; 608 #define kmem_cache_alloc_node(...) alloc_hooks(kmem_cache_alloc_node_noprof(__VA_ARGS__)) 609 610 /* 611 * These macros allow declaring a kmem_buckets * parameter alongside size, which 612 * can be compiled out with CONFIG_SLAB_BUCKETS=n so that a large number of call 613 * sites don't have to pass NULL. 614 */ 615 #ifdef CONFIG_SLAB_BUCKETS 616 #define DECL_BUCKET_PARAMS(_size, _b) size_t (_size), kmem_buckets *(_b) 617 #define PASS_BUCKET_PARAMS(_size, _b) (_size), (_b) 618 #define PASS_BUCKET_PARAM(_b) (_b) 619 #else 620 #define DECL_BUCKET_PARAMS(_size, _b) size_t (_size) 621 #define PASS_BUCKET_PARAMS(_size, _b) (_size) 622 #define PASS_BUCKET_PARAM(_b) NULL 623 #endif 624 625 /* 626 * The following functions are not to be used directly and are intended only 627 * for internal use from kmalloc() and kmalloc_node() 628 * with the exception of kunit tests 629 */ 630 631 void *__kmalloc_noprof(size_t size, gfp_t flags) 632 __assume_kmalloc_alignment __alloc_size(1); 633 634 void *__kmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node) 635 __assume_kmalloc_alignment __alloc_size(1); 636 637 void *__kmalloc_cache_noprof(struct kmem_cache *s, gfp_t flags, size_t size) 638 __assume_kmalloc_alignment __alloc_size(3); 639 640 void *__kmalloc_cache_node_noprof(struct kmem_cache *s, gfp_t gfpflags, 641 int node, size_t size) 642 __assume_kmalloc_alignment __alloc_size(4); 643 644 void *__kmalloc_large_noprof(size_t size, gfp_t flags) 645 __assume_page_alignment __alloc_size(1); 646 647 void *__kmalloc_large_node_noprof(size_t size, gfp_t flags, int node) 648 __assume_page_alignment __alloc_size(1); 649 650 /** 651 * kmalloc - allocate kernel memory 652 * @size: how many bytes of memory are required. 653 * @flags: describe the allocation context 654 * 655 * kmalloc is the normal method of allocating memory 656 * for objects smaller than page size in the kernel. 657 * 658 * The allocated object address is aligned to at least ARCH_KMALLOC_MINALIGN 659 * bytes. For @size of power of two bytes, the alignment is also guaranteed 660 * to be at least to the size. For other sizes, the alignment is guaranteed to 661 * be at least the largest power-of-two divisor of @size. 662 * 663 * The @flags argument may be one of the GFP flags defined at 664 * include/linux/gfp_types.h and described at 665 * :ref:`Documentation/core-api/mm-api.rst <mm-api-gfp-flags>` 666 * 667 * The recommended usage of the @flags is described at 668 * :ref:`Documentation/core-api/memory-allocation.rst <memory_allocation>` 669 * 670 * Below is a brief outline of the most useful GFP flags 671 * 672 * %GFP_KERNEL 673 * Allocate normal kernel ram. May sleep. 674 * 675 * %GFP_NOWAIT 676 * Allocation will not sleep. 677 * 678 * %GFP_ATOMIC 679 * Allocation will not sleep. May use emergency pools. 680 * 681 * Also it is possible to set different flags by OR'ing 682 * in one or more of the following additional @flags: 683 * 684 * %__GFP_ZERO 685 * Zero the allocated memory before returning. Also see kzalloc(). 686 * 687 * %__GFP_HIGH 688 * This allocation has high priority and may use emergency pools. 689 * 690 * %__GFP_NOFAIL 691 * Indicate that this allocation is in no way allowed to fail 692 * (think twice before using). 693 * 694 * %__GFP_NORETRY 695 * If memory is not immediately available, 696 * then give up at once. 697 * 698 * %__GFP_NOWARN 699 * If allocation fails, don't issue any warnings. 700 * 701 * %__GFP_RETRY_MAYFAIL 702 * Try really hard to succeed the allocation but fail 703 * eventually. 704 */ 705 static __always_inline __alloc_size(1) void *kmalloc_noprof(size_t size, gfp_t flags) 706 { 707 if (__builtin_constant_p(size) && size) { 708 unsigned int index; 709 710 if (size > KMALLOC_MAX_CACHE_SIZE) 711 return __kmalloc_large_noprof(size, flags); 712 713 index = kmalloc_index(size); 714 return __kmalloc_cache_noprof( 715 kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index], 716 flags, size); 717 } 718 return __kmalloc_noprof(size, flags); 719 } 720 #define kmalloc(...) alloc_hooks(kmalloc_noprof(__VA_ARGS__)) 721 722 #define kmem_buckets_alloc(_b, _size, _flags) \ 723 alloc_hooks(__kmalloc_node_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE)) 724 725 #define kmem_buckets_alloc_track_caller(_b, _size, _flags) \ 726 alloc_hooks(__kmalloc_node_track_caller_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE, _RET_IP_)) 727 728 static __always_inline __alloc_size(1) void *kmalloc_node_noprof(size_t size, gfp_t flags, int node) 729 { 730 if (__builtin_constant_p(size) && size) { 731 unsigned int index; 732 733 if (size > KMALLOC_MAX_CACHE_SIZE) 734 return __kmalloc_large_node_noprof(size, flags, node); 735 736 index = kmalloc_index(size); 737 return __kmalloc_cache_node_noprof( 738 kmalloc_caches[kmalloc_type(flags, _RET_IP_)][index], 739 flags, node, size); 740 } 741 return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node); 742 } 743 #define kmalloc_node(...) alloc_hooks(kmalloc_node_noprof(__VA_ARGS__)) 744 745 /** 746 * kmalloc_array - allocate memory for an array. 747 * @n: number of elements. 748 * @size: element size. 749 * @flags: the type of memory to allocate (see kmalloc). 750 */ 751 static inline __alloc_size(1, 2) void *kmalloc_array_noprof(size_t n, size_t size, gfp_t flags) 752 { 753 size_t bytes; 754 755 if (unlikely(check_mul_overflow(n, size, &bytes))) 756 return NULL; 757 if (__builtin_constant_p(n) && __builtin_constant_p(size)) 758 return kmalloc_noprof(bytes, flags); 759 return kmalloc_noprof(bytes, flags); 760 } 761 #define kmalloc_array(...) alloc_hooks(kmalloc_array_noprof(__VA_ARGS__)) 762 763 /** 764 * krealloc_array - reallocate memory for an array. 765 * @p: pointer to the memory chunk to reallocate 766 * @new_n: new number of elements to alloc 767 * @new_size: new size of a single member of the array 768 * @flags: the type of memory to allocate (see kmalloc) 769 */ 770 static inline __realloc_size(2, 3) void * __must_check krealloc_array_noprof(void *p, 771 size_t new_n, 772 size_t new_size, 773 gfp_t flags) 774 { 775 size_t bytes; 776 777 if (unlikely(check_mul_overflow(new_n, new_size, &bytes))) 778 return NULL; 779 780 return krealloc_noprof(p, bytes, flags); 781 } 782 #define krealloc_array(...) alloc_hooks(krealloc_array_noprof(__VA_ARGS__)) 783 784 /** 785 * kcalloc - allocate memory for an array. The memory is set to zero. 786 * @n: number of elements. 787 * @size: element size. 788 * @flags: the type of memory to allocate (see kmalloc). 789 */ 790 #define kcalloc(n, size, flags) kmalloc_array(n, size, (flags) | __GFP_ZERO) 791 792 void *__kmalloc_node_track_caller_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node, 793 unsigned long caller) __alloc_size(1); 794 #define kmalloc_node_track_caller_noprof(size, flags, node, caller) \ 795 __kmalloc_node_track_caller_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node, caller) 796 #define kmalloc_node_track_caller(...) \ 797 alloc_hooks(kmalloc_node_track_caller_noprof(__VA_ARGS__, _RET_IP_)) 798 799 /* 800 * kmalloc_track_caller is a special version of kmalloc that records the 801 * calling function of the routine calling it for slab leak tracking instead 802 * of just the calling function (confusing, eh?). 803 * It's useful when the call to kmalloc comes from a widely-used standard 804 * allocator where we care about the real place the memory allocation 805 * request comes from. 806 */ 807 #define kmalloc_track_caller(...) kmalloc_node_track_caller(__VA_ARGS__, NUMA_NO_NODE) 808 809 #define kmalloc_track_caller_noprof(...) \ 810 kmalloc_node_track_caller_noprof(__VA_ARGS__, NUMA_NO_NODE, _RET_IP_) 811 812 static inline __alloc_size(1, 2) void *kmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, 813 int node) 814 { 815 size_t bytes; 816 817 if (unlikely(check_mul_overflow(n, size, &bytes))) 818 return NULL; 819 if (__builtin_constant_p(n) && __builtin_constant_p(size)) 820 return kmalloc_node_noprof(bytes, flags, node); 821 return __kmalloc_node_noprof(PASS_BUCKET_PARAMS(bytes, NULL), flags, node); 822 } 823 #define kmalloc_array_node(...) alloc_hooks(kmalloc_array_node_noprof(__VA_ARGS__)) 824 825 #define kcalloc_node(_n, _size, _flags, _node) \ 826 kmalloc_array_node(_n, _size, (_flags) | __GFP_ZERO, _node) 827 828 /* 829 * Shortcuts 830 */ 831 #define kmem_cache_zalloc(_k, _flags) kmem_cache_alloc(_k, (_flags)|__GFP_ZERO) 832 833 /** 834 * kzalloc - allocate memory. The memory is set to zero. 835 * @size: how many bytes of memory are required. 836 * @flags: the type of memory to allocate (see kmalloc). 837 */ 838 static inline __alloc_size(1) void *kzalloc_noprof(size_t size, gfp_t flags) 839 { 840 return kmalloc_noprof(size, flags | __GFP_ZERO); 841 } 842 #define kzalloc(...) alloc_hooks(kzalloc_noprof(__VA_ARGS__)) 843 #define kzalloc_node(_size, _flags, _node) kmalloc_node(_size, (_flags)|__GFP_ZERO, _node) 844 845 void *__kvmalloc_node_noprof(DECL_BUCKET_PARAMS(size, b), gfp_t flags, int node) __alloc_size(1); 846 #define kvmalloc_node_noprof(size, flags, node) \ 847 __kvmalloc_node_noprof(PASS_BUCKET_PARAMS(size, NULL), flags, node) 848 #define kvmalloc_node(...) alloc_hooks(kvmalloc_node_noprof(__VA_ARGS__)) 849 850 #define kvmalloc(_size, _flags) kvmalloc_node(_size, _flags, NUMA_NO_NODE) 851 #define kvmalloc_noprof(_size, _flags) kvmalloc_node_noprof(_size, _flags, NUMA_NO_NODE) 852 #define kvzalloc(_size, _flags) kvmalloc(_size, (_flags)|__GFP_ZERO) 853 854 #define kvzalloc_node(_size, _flags, _node) kvmalloc_node(_size, (_flags)|__GFP_ZERO, _node) 855 #define kmem_buckets_valloc(_b, _size, _flags) \ 856 alloc_hooks(__kvmalloc_node_noprof(PASS_BUCKET_PARAMS(_size, _b), _flags, NUMA_NO_NODE)) 857 858 static inline __alloc_size(1, 2) void * 859 kvmalloc_array_node_noprof(size_t n, size_t size, gfp_t flags, int node) 860 { 861 size_t bytes; 862 863 if (unlikely(check_mul_overflow(n, size, &bytes))) 864 return NULL; 865 866 return kvmalloc_node_noprof(bytes, flags, node); 867 } 868 869 #define kvmalloc_array_noprof(...) kvmalloc_array_node_noprof(__VA_ARGS__, NUMA_NO_NODE) 870 #define kvcalloc_node_noprof(_n,_s,_f,_node) kvmalloc_array_node_noprof(_n,_s,(_f)|__GFP_ZERO,_node) 871 #define kvcalloc_noprof(...) kvcalloc_node_noprof(__VA_ARGS__, NUMA_NO_NODE) 872 873 #define kvmalloc_array(...) alloc_hooks(kvmalloc_array_noprof(__VA_ARGS__)) 874 #define kvcalloc_node(...) alloc_hooks(kvcalloc_node_noprof(__VA_ARGS__)) 875 #define kvcalloc(...) alloc_hooks(kvcalloc_noprof(__VA_ARGS__)) 876 877 extern void *kvrealloc_noprof(const void *p, size_t oldsize, size_t newsize, gfp_t flags) 878 __realloc_size(3); 879 #define kvrealloc(...) alloc_hooks(kvrealloc_noprof(__VA_ARGS__)) 880 881 extern void kvfree(const void *addr); 882 DEFINE_FREE(kvfree, void *, if (!IS_ERR_OR_NULL(_T)) kvfree(_T)) 883 884 extern void kvfree_sensitive(const void *addr, size_t len); 885 886 unsigned int kmem_cache_size(struct kmem_cache *s); 887 888 /** 889 * kmalloc_size_roundup - Report allocation bucket size for the given size 890 * 891 * @size: Number of bytes to round up from. 892 * 893 * This returns the number of bytes that would be available in a kmalloc() 894 * allocation of @size bytes. For example, a 126 byte request would be 895 * rounded up to the next sized kmalloc bucket, 128 bytes. (This is strictly 896 * for the general-purpose kmalloc()-based allocations, and is not for the 897 * pre-sized kmem_cache_alloc()-based allocations.) 898 * 899 * Use this to kmalloc() the full bucket size ahead of time instead of using 900 * ksize() to query the size after an allocation. 901 */ 902 size_t kmalloc_size_roundup(size_t size); 903 904 void __init kmem_cache_init_late(void); 905 906 #endif /* _LINUX_SLAB_H */ 907