genalloc.h (7866B)
1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Basic general purpose allocator for managing special purpose 4 * memory, for example, memory that is not managed by the regular 5 * kmalloc/kfree interface. Uses for this includes on-device special 6 * memory, uncached memory etc. 7 * 8 * It is safe to use the allocator in NMI handlers and other special 9 * unblockable contexts that could otherwise deadlock on locks. This 10 * is implemented by using atomic operations and retries on any 11 * conflicts. The disadvantage is that there may be livelocks in 12 * extreme cases. For better scalability, one allocator can be used 13 * for each CPU. 14 * 15 * The lockless operation only works if there is enough memory 16 * available. If new memory is added to the pool a lock has to be 17 * still taken. So any user relying on locklessness has to ensure 18 * that sufficient memory is preallocated. 19 * 20 * The basic atomic operation of this allocator is cmpxchg on long. 21 * On architectures that don't have NMI-safe cmpxchg implementation, 22 * the allocator can NOT be used in NMI handler. So code uses the 23 * allocator in NMI handler should depend on 24 * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG. 25 */ 26 27 28#ifndef __GENALLOC_H__ 29#define __GENALLOC_H__ 30 31#include <linux/types.h> 32#include <linux/spinlock_types.h> 33#include <linux/atomic.h> 34 35struct device; 36struct device_node; 37struct gen_pool; 38 39/** 40 * typedef genpool_algo_t: Allocation callback function type definition 41 * @map: Pointer to bitmap 42 * @size: The bitmap size in bits 43 * @start: The bitnumber to start searching at 44 * @nr: The number of zeroed bits we're looking for 45 * @data: optional additional data used by the callback 46 * @pool: the pool being allocated from 47 */ 48typedef unsigned long (*genpool_algo_t)(unsigned long *map, 49 unsigned long size, 50 unsigned long start, 51 unsigned int nr, 52 void *data, struct gen_pool *pool, 53 unsigned long start_addr); 54 55/* 56 * General purpose special memory pool descriptor. 57 */ 58struct gen_pool { 59 spinlock_t lock; 60 struct list_head chunks; /* list of chunks in this pool */ 61 int min_alloc_order; /* minimum allocation order */ 62 63 genpool_algo_t algo; /* allocation function */ 64 void *data; 65 66 const char *name; 67}; 68 69/* 70 * General purpose special memory pool chunk descriptor. 71 */ 72struct gen_pool_chunk { 73 struct list_head next_chunk; /* next chunk in pool */ 74 atomic_long_t avail; 75 phys_addr_t phys_addr; /* physical starting address of memory chunk */ 76 void *owner; /* private data to retrieve at alloc time */ 77 unsigned long start_addr; /* start address of memory chunk */ 78 unsigned long end_addr; /* end address of memory chunk (inclusive) */ 79 unsigned long bits[]; /* bitmap for allocating memory chunk */ 80}; 81 82/* 83 * gen_pool data descriptor for gen_pool_first_fit_align. 84 */ 85struct genpool_data_align { 86 int align; /* alignment by bytes for starting address */ 87}; 88 89/* 90 * gen_pool data descriptor for gen_pool_fixed_alloc. 91 */ 92struct genpool_data_fixed { 93 unsigned long offset; /* The offset of the specific region */ 94}; 95 96extern struct gen_pool *gen_pool_create(int, int); 97extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long); 98extern int gen_pool_add_owner(struct gen_pool *, unsigned long, phys_addr_t, 99 size_t, int, void *); 100 101static inline int gen_pool_add_virt(struct gen_pool *pool, unsigned long addr, 102 phys_addr_t phys, size_t size, int nid) 103{ 104 return gen_pool_add_owner(pool, addr, phys, size, nid, NULL); 105} 106 107/** 108 * gen_pool_add - add a new chunk of special memory to the pool 109 * @pool: pool to add new memory chunk to 110 * @addr: starting address of memory chunk to add to pool 111 * @size: size in bytes of the memory chunk to add to pool 112 * @nid: node id of the node the chunk structure and bitmap should be 113 * allocated on, or -1 114 * 115 * Add a new chunk of special memory to the specified pool. 116 * 117 * Returns 0 on success or a -ve errno on failure. 118 */ 119static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr, 120 size_t size, int nid) 121{ 122 return gen_pool_add_virt(pool, addr, -1, size, nid); 123} 124extern void gen_pool_destroy(struct gen_pool *); 125unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size, 126 genpool_algo_t algo, void *data, void **owner); 127 128static inline unsigned long gen_pool_alloc_owner(struct gen_pool *pool, 129 size_t size, void **owner) 130{ 131 return gen_pool_alloc_algo_owner(pool, size, pool->algo, pool->data, 132 owner); 133} 134 135static inline unsigned long gen_pool_alloc_algo(struct gen_pool *pool, 136 size_t size, genpool_algo_t algo, void *data) 137{ 138 return gen_pool_alloc_algo_owner(pool, size, algo, data, NULL); 139} 140 141/** 142 * gen_pool_alloc - allocate special memory from the pool 143 * @pool: pool to allocate from 144 * @size: number of bytes to allocate from the pool 145 * 146 * Allocate the requested number of bytes from the specified pool. 147 * Uses the pool allocation function (with first-fit algorithm by default). 148 * Can not be used in NMI handler on architectures without 149 * NMI-safe cmpxchg implementation. 150 */ 151static inline unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) 152{ 153 return gen_pool_alloc_algo(pool, size, pool->algo, pool->data); 154} 155 156extern void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, 157 dma_addr_t *dma); 158extern void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size, 159 dma_addr_t *dma, genpool_algo_t algo, void *data); 160extern void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size, 161 dma_addr_t *dma, int align); 162extern void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma); 163extern void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size, 164 dma_addr_t *dma, genpool_algo_t algo, void *data); 165extern void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size, 166 dma_addr_t *dma, int align); 167extern void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, 168 size_t size, void **owner); 169static inline void gen_pool_free(struct gen_pool *pool, unsigned long addr, 170 size_t size) 171{ 172 gen_pool_free_owner(pool, addr, size, NULL); 173} 174 175extern void gen_pool_for_each_chunk(struct gen_pool *, 176 void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *); 177extern size_t gen_pool_avail(struct gen_pool *); 178extern size_t gen_pool_size(struct gen_pool *); 179 180extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, 181 void *data); 182 183extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, 184 unsigned long start, unsigned int nr, void *data, 185 struct gen_pool *pool, unsigned long start_addr); 186 187extern unsigned long gen_pool_fixed_alloc(unsigned long *map, 188 unsigned long size, unsigned long start, unsigned int nr, 189 void *data, struct gen_pool *pool, unsigned long start_addr); 190 191extern unsigned long gen_pool_first_fit_align(unsigned long *map, 192 unsigned long size, unsigned long start, unsigned int nr, 193 void *data, struct gen_pool *pool, unsigned long start_addr); 194 195 196extern unsigned long gen_pool_first_fit_order_align(unsigned long *map, 197 unsigned long size, unsigned long start, unsigned int nr, 198 void *data, struct gen_pool *pool, unsigned long start_addr); 199 200extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, 201 unsigned long start, unsigned int nr, void *data, 202 struct gen_pool *pool, unsigned long start_addr); 203 204 205extern struct gen_pool *devm_gen_pool_create(struct device *dev, 206 int min_alloc_order, int nid, const char *name); 207extern struct gen_pool *gen_pool_get(struct device *dev, const char *name); 208 209extern bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start, 210 size_t size); 211 212#ifdef CONFIG_OF 213extern struct gen_pool *of_gen_pool_get(struct device_node *np, 214 const char *propname, int index); 215#else 216static inline struct gen_pool *of_gen_pool_get(struct device_node *np, 217 const char *propname, int index) 218{ 219 return NULL; 220} 221#endif 222#endif /* __GENALLOC_H__ */