1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1987, 1993 5 * The Regents of the University of California. 6 * Copyright (c) 2005, 2009 Robert N. M. Watson 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)malloc.h 8.5 (Berkeley) 5/3/95 34 * $FreeBSD$ 35 */ 36 37 #ifndef _SYS_MALLOC_H_ 38 #define _SYS_MALLOC_H_ 39 40 #include <sys/param.h> 41 #ifdef _KERNEL 42 #include <sys/systm.h> 43 #endif 44 #include <sys/queue.h> 45 #include <sys/_lock.h> 46 #include <sys/_mutex.h> 47 #include <machine/_limits.h> 48 49 #define MINALLOCSIZE UMA_SMALLEST_UNIT 50 51 /* 52 * Flags to memory allocation functions. 53 */ 54 #define M_NOWAIT 0x0001 /* do not block */ 55 #define M_WAITOK 0x0002 /* ok to block */ 56 #define M_ZERO 0x0100 /* bzero the allocation */ 57 #define M_NOVM 0x0200 /* don't ask VM for pages */ 58 #define M_USE_RESERVE 0x0400 /* can alloc out of reserve memory */ 59 #define M_NODUMP 0x0800 /* don't dump pages in this allocation */ 60 #define M_FIRSTFIT 0x1000 /* only for vmem, fast fit */ 61 #define M_BESTFIT 0x2000 /* only for vmem, low fragmentation */ 62 #define M_EXEC 0x4000 /* allocate executable space */ 63 #define M_NEXTFIT 0x8000 /* only for vmem, follow cursor */ 64 65 #define M_MAGIC 877983977 /* time when first defined :-) */ 66 67 /* 68 * Two malloc type structures are present: malloc_type, which is used by a 69 * type owner to declare the type, and malloc_type_internal, which holds 70 * malloc-owned statistics and other ABI-sensitive fields, such as the set of 71 * malloc statistics indexed by the compile-time MAXCPU constant. 72 * Applications should avoid introducing dependence on the allocator private 73 * data layout and size. 74 * 75 * The malloc_type ks_next field is protected by malloc_mtx. Other fields in 76 * malloc_type are static after initialization so unsynchronized. 77 * 78 * Statistics in malloc_type_stats are written only when holding a critical 79 * section and running on the CPU associated with the index into the stat 80 * array, but read lock-free resulting in possible (minor) races, which the 81 * monitoring app should take into account. 82 */ 83 struct malloc_type_stats { 84 uint64_t mts_memalloced; /* Bytes allocated on CPU. */ 85 uint64_t mts_memfreed; /* Bytes freed on CPU. */ 86 uint64_t mts_numallocs; /* Number of allocates on CPU. */ 87 uint64_t mts_numfrees; /* number of frees on CPU. */ 88 uint64_t mts_size; /* Bitmask of sizes allocated on CPU. */ 89 uint64_t _mts_reserved1; /* Reserved field. */ 90 uint64_t _mts_reserved2; /* Reserved field. */ 91 uint64_t _mts_reserved3; /* Reserved field. */ 92 }; 93 94 /* 95 * Index definitions for the mti_probes[] array. 96 */ 97 #define DTMALLOC_PROBE_MALLOC 0 98 #define DTMALLOC_PROBE_FREE 1 99 #define DTMALLOC_PROBE_MAX 2 100 101 struct malloc_type_internal { 102 uint32_t mti_probes[DTMALLOC_PROBE_MAX]; 103 /* DTrace probe ID array. */ 104 u_char mti_zone; 105 struct malloc_type_stats *mti_stats; 106 }; 107 108 /* 109 * Public data structure describing a malloc type. Private data is hung off 110 * of ks_handle to avoid encoding internal malloc(9) data structures in 111 * modules, which will statically allocate struct malloc_type. 112 */ 113 struct malloc_type { 114 struct malloc_type *ks_next; /* Next in global chain. */ 115 u_long ks_magic; /* Detect programmer error. */ 116 const char *ks_shortdesc; /* Printable type name. */ 117 void *ks_handle; /* Priv. data, was lo_class. */ 118 }; 119 120 /* 121 * Statistics structure headers for user space. The kern.malloc sysctl 122 * exposes a structure stream consisting of a stream header, then a series of 123 * malloc type headers and statistics structures (quantity maxcpus). For 124 * convenience, the kernel will provide the current value of maxcpus at the 125 * head of the stream. 126 */ 127 #define MALLOC_TYPE_STREAM_VERSION 0x00000001 128 struct malloc_type_stream_header { 129 uint32_t mtsh_version; /* Stream format version. */ 130 uint32_t mtsh_maxcpus; /* Value of MAXCPU for stream. */ 131 uint32_t mtsh_count; /* Number of records. */ 132 uint32_t _mtsh_pad; /* Pad/reserved field. */ 133 }; 134 135 #define MALLOC_MAX_NAME 32 136 struct malloc_type_header { 137 char mth_name[MALLOC_MAX_NAME]; 138 }; 139 140 #ifdef _KERNEL 141 #define MALLOC_DEFINE(type, shortdesc, longdesc) \ 142 struct malloc_type type[1] = { \ 143 { NULL, M_MAGIC, shortdesc, NULL } \ 144 }; \ 145 SYSINIT(type##_init, SI_SUB_KMEM, SI_ORDER_THIRD, malloc_init, \ 146 type); \ 147 SYSUNINIT(type##_uninit, SI_SUB_KMEM, SI_ORDER_ANY, \ 148 malloc_uninit, type) 149 150 #define MALLOC_DECLARE(type) \ 151 extern struct malloc_type type[1] 152 153 MALLOC_DECLARE(M_CACHE); 154 MALLOC_DECLARE(M_DEVBUF); 155 MALLOC_DECLARE(M_TEMP); 156 157 /* 158 * XXX this should be declared in <sys/uio.h>, but that tends to fail 159 * because <sys/uio.h> is included in a header before the source file 160 * has a chance to include <sys/malloc.h> to get MALLOC_DECLARE() defined. 161 */ 162 MALLOC_DECLARE(M_IOV); 163 164 struct domainset; 165 extern struct mtx malloc_mtx; 166 167 /* 168 * Function type used when iterating over the list of malloc types. 169 */ 170 typedef void malloc_type_list_func_t(struct malloc_type *, void *); 171 172 void contigfree(void *addr, unsigned long size, struct malloc_type *type); 173 void *contigmalloc(unsigned long size, struct malloc_type *type, int flags, 174 vm_paddr_t low, vm_paddr_t high, unsigned long alignment, 175 vm_paddr_t boundary) __malloc_like __result_use_check 176 __alloc_size(1) __alloc_align(6); 177 void *contigmalloc_domainset(unsigned long size, struct malloc_type *type, 178 struct domainset *ds, int flags, vm_paddr_t low, vm_paddr_t high, 179 unsigned long alignment, vm_paddr_t boundary) 180 __malloc_like __result_use_check __alloc_size(1) __alloc_align(7); 181 void free(void *addr, struct malloc_type *type); 182 void free_domain(void *addr, struct malloc_type *type); 183 void *malloc(size_t size, struct malloc_type *type, int flags) __malloc_like 184 __result_use_check __alloc_size(1); 185 /* 186 * Try to optimize malloc(..., ..., M_ZERO) allocations by doing zeroing in 187 * place if the size is known at compilation time. 188 * 189 * Passing the flag down requires malloc to blindly zero the entire object. 190 * In practice a lot of the zeroing can be avoided if most of the object 191 * gets explicitly initialized after the allocation. Letting the compiler 192 * zero in place gives it the opportunity to take advantage of this state. 193 * 194 * Note that the operation is only applicable if both flags and size are 195 * known at compilation time. If M_ZERO is passed but M_WAITOK is not, the 196 * allocation can fail and a NULL check is needed. However, if M_WAITOK is 197 * passed we know the allocation must succeed and the check can be elided. 198 * 199 * _malloc_item = malloc(_size, type, (flags) &~ M_ZERO); 200 * if (((flags) & M_WAITOK) != 0 || _malloc_item != NULL) 201 * bzero(_malloc_item, _size); 202 * 203 * If the flag is set, the compiler knows the left side is always true, 204 * therefore the entire statement is true and the callsite is: 205 * 206 * _malloc_item = malloc(_size, type, (flags) &~ M_ZERO); 207 * bzero(_malloc_item, _size); 208 * 209 * If the flag is not set, the compiler knows the left size is always false 210 * and the NULL check is needed, therefore the callsite is: 211 * 212 * _malloc_item = malloc(_size, type, (flags) &~ M_ZERO); 213 * if (_malloc_item != NULL) 214 * bzero(_malloc_item, _size); 215 * 216 * The implementation is a macro because of what appears to be a clang 6 bug: 217 * an inline function variant ended up being compiled to a mere malloc call 218 * regardless of argument. gcc generates expected code (like the above). 219 */ 220 #define malloc(size, type, flags) ({ \ 221 void *_malloc_item; \ 222 size_t _size = (size); \ 223 if (__builtin_constant_p(size) && __builtin_constant_p(flags) &&\ 224 ((flags) & M_ZERO) != 0) { \ 225 _malloc_item = malloc(_size, type, (flags) &~ M_ZERO); \ 226 if (((flags) & M_WAITOK) != 0 || \ 227 __predict_true(_malloc_item != NULL)) \ 228 bzero(_malloc_item, _size); \ 229 } else { \ 230 _malloc_item = malloc(_size, type, flags); \ 231 } \ 232 _malloc_item; \ 233 }) 234 235 void *malloc_domainset(size_t size, struct malloc_type *type, 236 struct domainset *ds, int flags) __malloc_like __result_use_check 237 __alloc_size(1); 238 void *mallocarray(size_t nmemb, size_t size, struct malloc_type *type, 239 int flags) __malloc_like __result_use_check 240 __alloc_size2(1, 2); 241 void malloc_init(void *); 242 int malloc_last_fail(void); 243 void malloc_type_allocated(struct malloc_type *type, unsigned long size); 244 void malloc_type_freed(struct malloc_type *type, unsigned long size); 245 void malloc_type_list(malloc_type_list_func_t *, void *); 246 void malloc_uninit(void *); 247 void *realloc(void *addr, size_t size, struct malloc_type *type, int flags) 248 __result_use_check __alloc_size(2); 249 void *reallocf(void *addr, size_t size, struct malloc_type *type, int flags) 250 __result_use_check __alloc_size(2); 251 252 struct malloc_type *malloc_desc2type(const char *desc); 253 254 /* 255 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX 256 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW 257 */ 258 #define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 8 / 2)) 259 static inline bool 260 WOULD_OVERFLOW(size_t nmemb, size_t size) 261 { 262 263 return ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && 264 nmemb > 0 && __SIZE_T_MAX / nmemb < size); 265 } 266 #undef MUL_NO_OVERFLOW 267 #endif /* _KERNEL */ 268 269 #endif /* !_SYS_MALLOC_H_ */ 270