1 /* 2 * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved. 3 * 4 * SPDX-License-Identifier: BSD-3-Clause 5 */ 6 7 #ifndef OBJECT_POOL_H 8 #define OBJECT_POOL_H 9 10 #include <debug.h> 11 #include <stdlib.h> 12 #include <utils_def.h> 13 14 /* 15 * Pool of statically allocated objects. 16 * 17 * Objects can be reserved but not freed. This is by design and it is not a 18 * limitation. We do not want to introduce complexity induced by memory freeing, 19 * such as use-after-free bugs, memory fragmentation and so on. 20 * 21 * The object size and capacity of the pool are fixed at build time. So is the 22 * address of the objects back store. 23 */ 24 struct object_pool { 25 /* Size of 1 object in the pool in byte unit. */ 26 const size_t obj_size; 27 28 /* Number of objects in the pool. */ 29 const size_t capacity; 30 31 /* Objects back store. */ 32 void *const objects; 33 34 /* How many objects are currently allocated. */ 35 size_t used; 36 }; 37 38 /* Create a static pool of objects. */ 39 #define OBJECT_POOL(_pool_name, _obj_backstore, _obj_size, _obj_count) \ 40 struct object_pool _pool_name = { \ 41 .objects = (_obj_backstore), \ 42 .obj_size = (_obj_size), \ 43 .capacity = (_obj_count), \ 44 .used = 0U, \ 45 } 46 47 /* Create a static pool of objects out of an array of pre-allocated objects. */ 48 #define OBJECT_POOL_ARRAY(_pool_name, _obj_array) \ 49 OBJECT_POOL(_pool_name, (_obj_array), \ 50 sizeof((_obj_array)[0]), ARRAY_SIZE(_obj_array)) 51 52 /* 53 * Allocate 'count' objects from a pool. 54 * Return the address of the first object. Panic on error. 55 */ 56 static inline void *pool_alloc_n(struct object_pool *pool, size_t count) 57 { 58 if (pool->used + count > pool->capacity) { 59 ERROR("Cannot allocate %zu objects out of pool (%zu objects left).\n", 60 count, pool->capacity - pool->used); 61 panic(); 62 } 63 64 void *obj = (char *)(pool->objects) + pool->obj_size * pool->used; 65 pool->used += count; 66 return obj; 67 } 68 69 /* 70 * Allocate 1 object from a pool. 71 * Return the address of the object. Panic on error. 72 */ 73 static inline void *pool_alloc(struct object_pool *pool) 74 { 75 return pool_alloc_n(pool, 1U); 76 } 77 78 #endif /* OBJECT_POOL_H */ 79