xref: /openbmc/linux/lib/genalloc.c (revision 077ca040)
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  * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
27  */
28 
29 #include <linux/slab.h>
30 #include <linux/export.h>
31 #include <linux/bitmap.h>
32 #include <linux/rculist.h>
33 #include <linux/interrupt.h>
34 #include <linux/genalloc.h>
35 #include <linux/of.h>
36 #include <linux/of_platform.h>
37 #include <linux/platform_device.h>
38 #include <linux/vmalloc.h>
39 
chunk_size(const struct gen_pool_chunk * chunk)40 static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
41 {
42 	return chunk->end_addr - chunk->start_addr + 1;
43 }
44 
45 static inline int
set_bits_ll(unsigned long * addr,unsigned long mask_to_set)46 set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
47 {
48 	unsigned long val = READ_ONCE(*addr);
49 
50 	do {
51 		if (val & mask_to_set)
52 			return -EBUSY;
53 		cpu_relax();
54 	} while (!try_cmpxchg(addr, &val, val | mask_to_set));
55 
56 	return 0;
57 }
58 
59 static inline int
clear_bits_ll(unsigned long * addr,unsigned long mask_to_clear)60 clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
61 {
62 	unsigned long val = READ_ONCE(*addr);
63 
64 	do {
65 		if ((val & mask_to_clear) != mask_to_clear)
66 			return -EBUSY;
67 		cpu_relax();
68 	} while (!try_cmpxchg(addr, &val, val & ~mask_to_clear));
69 
70 	return 0;
71 }
72 
73 /*
74  * bitmap_set_ll - set the specified number of bits at the specified position
75  * @map: pointer to a bitmap
76  * @start: a bit position in @map
77  * @nr: number of bits to set
78  *
79  * Set @nr bits start from @start in @map lock-lessly. Several users
80  * can set/clear the same bitmap simultaneously without lock. If two
81  * users set the same bit, one user will return remain bits, otherwise
82  * return 0.
83  */
84 static unsigned long
bitmap_set_ll(unsigned long * map,unsigned long start,unsigned long nr)85 bitmap_set_ll(unsigned long *map, unsigned long start, unsigned long nr)
86 {
87 	unsigned long *p = map + BIT_WORD(start);
88 	const unsigned long size = start + nr;
89 	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
90 	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
91 
92 	while (nr >= bits_to_set) {
93 		if (set_bits_ll(p, mask_to_set))
94 			return nr;
95 		nr -= bits_to_set;
96 		bits_to_set = BITS_PER_LONG;
97 		mask_to_set = ~0UL;
98 		p++;
99 	}
100 	if (nr) {
101 		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
102 		if (set_bits_ll(p, mask_to_set))
103 			return nr;
104 	}
105 
106 	return 0;
107 }
108 
109 /*
110  * bitmap_clear_ll - clear the specified number of bits at the specified position
111  * @map: pointer to a bitmap
112  * @start: a bit position in @map
113  * @nr: number of bits to set
114  *
115  * Clear @nr bits start from @start in @map lock-lessly. Several users
116  * can set/clear the same bitmap simultaneously without lock. If two
117  * users clear the same bit, one user will return remain bits,
118  * otherwise return 0.
119  */
120 static unsigned long
bitmap_clear_ll(unsigned long * map,unsigned long start,unsigned long nr)121 bitmap_clear_ll(unsigned long *map, unsigned long start, unsigned long nr)
122 {
123 	unsigned long *p = map + BIT_WORD(start);
124 	const unsigned long size = start + nr;
125 	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
126 	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
127 
128 	while (nr >= bits_to_clear) {
129 		if (clear_bits_ll(p, mask_to_clear))
130 			return nr;
131 		nr -= bits_to_clear;
132 		bits_to_clear = BITS_PER_LONG;
133 		mask_to_clear = ~0UL;
134 		p++;
135 	}
136 	if (nr) {
137 		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
138 		if (clear_bits_ll(p, mask_to_clear))
139 			return nr;
140 	}
141 
142 	return 0;
143 }
144 
145 /**
146  * gen_pool_create - create a new special memory pool
147  * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
148  * @nid: node id of the node the pool structure should be allocated on, or -1
149  *
150  * Create a new special memory pool that can be used to manage special purpose
151  * memory not managed by the regular kmalloc/kfree interface.
152  */
gen_pool_create(int min_alloc_order,int nid)153 struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
154 {
155 	struct gen_pool *pool;
156 
157 	pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
158 	if (pool != NULL) {
159 		spin_lock_init(&pool->lock);
160 		INIT_LIST_HEAD(&pool->chunks);
161 		pool->min_alloc_order = min_alloc_order;
162 		pool->algo = gen_pool_first_fit;
163 		pool->data = NULL;
164 		pool->name = NULL;
165 	}
166 	return pool;
167 }
168 EXPORT_SYMBOL(gen_pool_create);
169 
170 /**
171  * gen_pool_add_owner- add a new chunk of special memory to the pool
172  * @pool: pool to add new memory chunk to
173  * @virt: virtual starting address of memory chunk to add to pool
174  * @phys: physical starting address of memory chunk to add to pool
175  * @size: size in bytes of the memory chunk to add to pool
176  * @nid: node id of the node the chunk structure and bitmap should be
177  *       allocated on, or -1
178  * @owner: private data the publisher would like to recall at alloc time
179  *
180  * Add a new chunk of special memory to the specified pool.
181  *
182  * Returns 0 on success or a -ve errno on failure.
183  */
gen_pool_add_owner(struct gen_pool * pool,unsigned long virt,phys_addr_t phys,size_t size,int nid,void * owner)184 int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
185 		 size_t size, int nid, void *owner)
186 {
187 	struct gen_pool_chunk *chunk;
188 	unsigned long nbits = size >> pool->min_alloc_order;
189 	unsigned long nbytes = sizeof(struct gen_pool_chunk) +
190 				BITS_TO_LONGS(nbits) * sizeof(long);
191 
192 	chunk = vzalloc_node(nbytes, nid);
193 	if (unlikely(chunk == NULL))
194 		return -ENOMEM;
195 
196 	chunk->phys_addr = phys;
197 	chunk->start_addr = virt;
198 	chunk->end_addr = virt + size - 1;
199 	chunk->owner = owner;
200 	atomic_long_set(&chunk->avail, size);
201 
202 	spin_lock(&pool->lock);
203 	list_add_rcu(&chunk->next_chunk, &pool->chunks);
204 	spin_unlock(&pool->lock);
205 
206 	return 0;
207 }
208 EXPORT_SYMBOL(gen_pool_add_owner);
209 
210 /**
211  * gen_pool_virt_to_phys - return the physical address of memory
212  * @pool: pool to allocate from
213  * @addr: starting address of memory
214  *
215  * Returns the physical address on success, or -1 on error.
216  */
gen_pool_virt_to_phys(struct gen_pool * pool,unsigned long addr)217 phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
218 {
219 	struct gen_pool_chunk *chunk;
220 	phys_addr_t paddr = -1;
221 
222 	rcu_read_lock();
223 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
224 		if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
225 			paddr = chunk->phys_addr + (addr - chunk->start_addr);
226 			break;
227 		}
228 	}
229 	rcu_read_unlock();
230 
231 	return paddr;
232 }
233 EXPORT_SYMBOL(gen_pool_virt_to_phys);
234 
235 /**
236  * gen_pool_destroy - destroy a special memory pool
237  * @pool: pool to destroy
238  *
239  * Destroy the specified special memory pool. Verifies that there are no
240  * outstanding allocations.
241  */
gen_pool_destroy(struct gen_pool * pool)242 void gen_pool_destroy(struct gen_pool *pool)
243 {
244 	struct list_head *_chunk, *_next_chunk;
245 	struct gen_pool_chunk *chunk;
246 	int order = pool->min_alloc_order;
247 	unsigned long bit, end_bit;
248 
249 	list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
250 		chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
251 		list_del(&chunk->next_chunk);
252 
253 		end_bit = chunk_size(chunk) >> order;
254 		bit = find_first_bit(chunk->bits, end_bit);
255 		BUG_ON(bit < end_bit);
256 
257 		vfree(chunk);
258 	}
259 	kfree_const(pool->name);
260 	kfree(pool);
261 }
262 EXPORT_SYMBOL(gen_pool_destroy);
263 
264 /**
265  * gen_pool_alloc_algo_owner - allocate special memory from the pool
266  * @pool: pool to allocate from
267  * @size: number of bytes to allocate from the pool
268  * @algo: algorithm passed from caller
269  * @data: data passed to algorithm
270  * @owner: optionally retrieve the chunk owner
271  *
272  * Allocate the requested number of bytes from the specified pool.
273  * Uses the pool allocation function (with first-fit algorithm by default).
274  * Can not be used in NMI handler on architectures without
275  * NMI-safe cmpxchg implementation.
276  */
gen_pool_alloc_algo_owner(struct gen_pool * pool,size_t size,genpool_algo_t algo,void * data,void ** owner)277 unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
278 		genpool_algo_t algo, void *data, void **owner)
279 {
280 	struct gen_pool_chunk *chunk;
281 	unsigned long addr = 0;
282 	int order = pool->min_alloc_order;
283 	unsigned long nbits, start_bit, end_bit, remain;
284 
285 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
286 	BUG_ON(in_nmi());
287 #endif
288 
289 	if (owner)
290 		*owner = NULL;
291 
292 	if (size == 0)
293 		return 0;
294 
295 	nbits = (size + (1UL << order) - 1) >> order;
296 	rcu_read_lock();
297 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
298 		if (size > atomic_long_read(&chunk->avail))
299 			continue;
300 
301 		start_bit = 0;
302 		end_bit = chunk_size(chunk) >> order;
303 retry:
304 		start_bit = algo(chunk->bits, end_bit, start_bit,
305 				 nbits, data, pool, chunk->start_addr);
306 		if (start_bit >= end_bit)
307 			continue;
308 		remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
309 		if (remain) {
310 			remain = bitmap_clear_ll(chunk->bits, start_bit,
311 						 nbits - remain);
312 			BUG_ON(remain);
313 			goto retry;
314 		}
315 
316 		addr = chunk->start_addr + ((unsigned long)start_bit << order);
317 		size = nbits << order;
318 		atomic_long_sub(size, &chunk->avail);
319 		if (owner)
320 			*owner = chunk->owner;
321 		break;
322 	}
323 	rcu_read_unlock();
324 	return addr;
325 }
326 EXPORT_SYMBOL(gen_pool_alloc_algo_owner);
327 
328 /**
329  * gen_pool_dma_alloc - allocate special memory from the pool for DMA usage
330  * @pool: pool to allocate from
331  * @size: number of bytes to allocate from the pool
332  * @dma: dma-view physical address return value.  Use %NULL if unneeded.
333  *
334  * Allocate the requested number of bytes from the specified pool.
335  * Uses the pool allocation function (with first-fit algorithm by default).
336  * Can not be used in NMI handler on architectures without
337  * NMI-safe cmpxchg implementation.
338  *
339  * Return: virtual address of the allocated memory, or %NULL on failure
340  */
gen_pool_dma_alloc(struct gen_pool * pool,size_t size,dma_addr_t * dma)341 void *gen_pool_dma_alloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
342 {
343 	return gen_pool_dma_alloc_algo(pool, size, dma, pool->algo, pool->data);
344 }
345 EXPORT_SYMBOL(gen_pool_dma_alloc);
346 
347 /**
348  * gen_pool_dma_alloc_algo - allocate special memory from the pool for DMA
349  * usage with the given pool algorithm
350  * @pool: pool to allocate from
351  * @size: number of bytes to allocate from the pool
352  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
353  * @algo: algorithm passed from caller
354  * @data: data passed to algorithm
355  *
356  * Allocate the requested number of bytes from the specified pool. Uses the
357  * given pool allocation function. Can not be used in NMI handler on
358  * architectures without NMI-safe cmpxchg implementation.
359  *
360  * Return: virtual address of the allocated memory, or %NULL on failure
361  */
gen_pool_dma_alloc_algo(struct gen_pool * pool,size_t size,dma_addr_t * dma,genpool_algo_t algo,void * data)362 void *gen_pool_dma_alloc_algo(struct gen_pool *pool, size_t size,
363 		dma_addr_t *dma, genpool_algo_t algo, void *data)
364 {
365 	unsigned long vaddr;
366 
367 	if (!pool)
368 		return NULL;
369 
370 	vaddr = gen_pool_alloc_algo(pool, size, algo, data);
371 	if (!vaddr)
372 		return NULL;
373 
374 	if (dma)
375 		*dma = gen_pool_virt_to_phys(pool, vaddr);
376 
377 	return (void *)vaddr;
378 }
379 EXPORT_SYMBOL(gen_pool_dma_alloc_algo);
380 
381 /**
382  * gen_pool_dma_alloc_align - allocate special memory from the pool for DMA
383  * usage with the given alignment
384  * @pool: pool to allocate from
385  * @size: number of bytes to allocate from the pool
386  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
387  * @align: alignment in bytes for starting address
388  *
389  * Allocate the requested number bytes from the specified pool, with the given
390  * alignment restriction. Can not be used in NMI handler on architectures
391  * without NMI-safe cmpxchg implementation.
392  *
393  * Return: virtual address of the allocated memory, or %NULL on failure
394  */
gen_pool_dma_alloc_align(struct gen_pool * pool,size_t size,dma_addr_t * dma,int align)395 void *gen_pool_dma_alloc_align(struct gen_pool *pool, size_t size,
396 		dma_addr_t *dma, int align)
397 {
398 	struct genpool_data_align data = { .align = align };
399 
400 	return gen_pool_dma_alloc_algo(pool, size, dma,
401 			gen_pool_first_fit_align, &data);
402 }
403 EXPORT_SYMBOL(gen_pool_dma_alloc_align);
404 
405 /**
406  * gen_pool_dma_zalloc - allocate special zeroed memory from the pool for
407  * DMA usage
408  * @pool: pool to allocate from
409  * @size: number of bytes to allocate from the pool
410  * @dma: dma-view physical address return value.  Use %NULL if unneeded.
411  *
412  * Allocate the requested number of zeroed bytes from the specified pool.
413  * Uses the pool allocation function (with first-fit algorithm by default).
414  * Can not be used in NMI handler on architectures without
415  * NMI-safe cmpxchg implementation.
416  *
417  * Return: virtual address of the allocated zeroed memory, or %NULL on failure
418  */
gen_pool_dma_zalloc(struct gen_pool * pool,size_t size,dma_addr_t * dma)419 void *gen_pool_dma_zalloc(struct gen_pool *pool, size_t size, dma_addr_t *dma)
420 {
421 	return gen_pool_dma_zalloc_algo(pool, size, dma, pool->algo, pool->data);
422 }
423 EXPORT_SYMBOL(gen_pool_dma_zalloc);
424 
425 /**
426  * gen_pool_dma_zalloc_algo - allocate special zeroed memory from the pool for
427  * DMA usage with the given pool algorithm
428  * @pool: pool to allocate from
429  * @size: number of bytes to allocate from the pool
430  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
431  * @algo: algorithm passed from caller
432  * @data: data passed to algorithm
433  *
434  * Allocate the requested number of zeroed bytes from the specified pool. Uses
435  * the given pool allocation function. Can not be used in NMI handler on
436  * architectures without NMI-safe cmpxchg implementation.
437  *
438  * Return: virtual address of the allocated zeroed memory, or %NULL on failure
439  */
gen_pool_dma_zalloc_algo(struct gen_pool * pool,size_t size,dma_addr_t * dma,genpool_algo_t algo,void * data)440 void *gen_pool_dma_zalloc_algo(struct gen_pool *pool, size_t size,
441 		dma_addr_t *dma, genpool_algo_t algo, void *data)
442 {
443 	void *vaddr = gen_pool_dma_alloc_algo(pool, size, dma, algo, data);
444 
445 	if (vaddr)
446 		memset(vaddr, 0, size);
447 
448 	return vaddr;
449 }
450 EXPORT_SYMBOL(gen_pool_dma_zalloc_algo);
451 
452 /**
453  * gen_pool_dma_zalloc_align - allocate special zeroed memory from the pool for
454  * DMA usage with the given alignment
455  * @pool: pool to allocate from
456  * @size: number of bytes to allocate from the pool
457  * @dma: DMA-view physical address return value. Use %NULL if unneeded.
458  * @align: alignment in bytes for starting address
459  *
460  * Allocate the requested number of zeroed bytes from the specified pool,
461  * with the given alignment restriction. Can not be used in NMI handler on
462  * architectures without NMI-safe cmpxchg implementation.
463  *
464  * Return: virtual address of the allocated zeroed memory, or %NULL on failure
465  */
gen_pool_dma_zalloc_align(struct gen_pool * pool,size_t size,dma_addr_t * dma,int align)466 void *gen_pool_dma_zalloc_align(struct gen_pool *pool, size_t size,
467 		dma_addr_t *dma, int align)
468 {
469 	struct genpool_data_align data = { .align = align };
470 
471 	return gen_pool_dma_zalloc_algo(pool, size, dma,
472 			gen_pool_first_fit_align, &data);
473 }
474 EXPORT_SYMBOL(gen_pool_dma_zalloc_align);
475 
476 /**
477  * gen_pool_free_owner - free allocated special memory back to the pool
478  * @pool: pool to free to
479  * @addr: starting address of memory to free back to pool
480  * @size: size in bytes of memory to free
481  * @owner: private data stashed at gen_pool_add() time
482  *
483  * Free previously allocated special memory back to the specified
484  * pool.  Can not be used in NMI handler on architectures without
485  * NMI-safe cmpxchg implementation.
486  */
gen_pool_free_owner(struct gen_pool * pool,unsigned long addr,size_t size,void ** owner)487 void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size,
488 		void **owner)
489 {
490 	struct gen_pool_chunk *chunk;
491 	int order = pool->min_alloc_order;
492 	unsigned long start_bit, nbits, remain;
493 
494 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
495 	BUG_ON(in_nmi());
496 #endif
497 
498 	if (owner)
499 		*owner = NULL;
500 
501 	nbits = (size + (1UL << order) - 1) >> order;
502 	rcu_read_lock();
503 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
504 		if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
505 			BUG_ON(addr + size - 1 > chunk->end_addr);
506 			start_bit = (addr - chunk->start_addr) >> order;
507 			remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
508 			BUG_ON(remain);
509 			size = nbits << order;
510 			atomic_long_add(size, &chunk->avail);
511 			if (owner)
512 				*owner = chunk->owner;
513 			rcu_read_unlock();
514 			return;
515 		}
516 	}
517 	rcu_read_unlock();
518 	BUG();
519 }
520 EXPORT_SYMBOL(gen_pool_free_owner);
521 
522 /**
523  * gen_pool_for_each_chunk - call func for every chunk of generic memory pool
524  * @pool:	the generic memory pool
525  * @func:	func to call
526  * @data:	additional data used by @func
527  *
528  * Call @func for every chunk of generic memory pool.  The @func is
529  * called with rcu_read_lock held.
530  */
gen_pool_for_each_chunk(struct gen_pool * pool,void (* func)(struct gen_pool * pool,struct gen_pool_chunk * chunk,void * data),void * data)531 void gen_pool_for_each_chunk(struct gen_pool *pool,
532 	void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
533 	void *data)
534 {
535 	struct gen_pool_chunk *chunk;
536 
537 	rcu_read_lock();
538 	list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
539 		func(pool, chunk, data);
540 	rcu_read_unlock();
541 }
542 EXPORT_SYMBOL(gen_pool_for_each_chunk);
543 
544 /**
545  * gen_pool_has_addr - checks if an address falls within the range of a pool
546  * @pool:	the generic memory pool
547  * @start:	start address
548  * @size:	size of the region
549  *
550  * Check if the range of addresses falls within the specified pool. Returns
551  * true if the entire range is contained in the pool and false otherwise.
552  */
gen_pool_has_addr(struct gen_pool * pool,unsigned long start,size_t size)553 bool gen_pool_has_addr(struct gen_pool *pool, unsigned long start,
554 			size_t size)
555 {
556 	bool found = false;
557 	unsigned long end = start + size - 1;
558 	struct gen_pool_chunk *chunk;
559 
560 	rcu_read_lock();
561 	list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk) {
562 		if (start >= chunk->start_addr && start <= chunk->end_addr) {
563 			if (end <= chunk->end_addr) {
564 				found = true;
565 				break;
566 			}
567 		}
568 	}
569 	rcu_read_unlock();
570 	return found;
571 }
572 EXPORT_SYMBOL(gen_pool_has_addr);
573 
574 /**
575  * gen_pool_avail - get available free space of the pool
576  * @pool: pool to get available free space
577  *
578  * Return available free space of the specified pool.
579  */
gen_pool_avail(struct gen_pool * pool)580 size_t gen_pool_avail(struct gen_pool *pool)
581 {
582 	struct gen_pool_chunk *chunk;
583 	size_t avail = 0;
584 
585 	rcu_read_lock();
586 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
587 		avail += atomic_long_read(&chunk->avail);
588 	rcu_read_unlock();
589 	return avail;
590 }
591 EXPORT_SYMBOL_GPL(gen_pool_avail);
592 
593 /**
594  * gen_pool_size - get size in bytes of memory managed by the pool
595  * @pool: pool to get size
596  *
597  * Return size in bytes of memory managed by the pool.
598  */
gen_pool_size(struct gen_pool * pool)599 size_t gen_pool_size(struct gen_pool *pool)
600 {
601 	struct gen_pool_chunk *chunk;
602 	size_t size = 0;
603 
604 	rcu_read_lock();
605 	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
606 		size += chunk_size(chunk);
607 	rcu_read_unlock();
608 	return size;
609 }
610 EXPORT_SYMBOL_GPL(gen_pool_size);
611 
612 /**
613  * gen_pool_set_algo - set the allocation algorithm
614  * @pool: pool to change allocation algorithm
615  * @algo: custom algorithm function
616  * @data: additional data used by @algo
617  *
618  * Call @algo for each memory allocation in the pool.
619  * If @algo is NULL use gen_pool_first_fit as default
620  * memory allocation function.
621  */
gen_pool_set_algo(struct gen_pool * pool,genpool_algo_t algo,void * data)622 void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
623 {
624 	rcu_read_lock();
625 
626 	pool->algo = algo;
627 	if (!pool->algo)
628 		pool->algo = gen_pool_first_fit;
629 
630 	pool->data = data;
631 
632 	rcu_read_unlock();
633 }
634 EXPORT_SYMBOL(gen_pool_set_algo);
635 
636 /**
637  * gen_pool_first_fit - find the first available region
638  * of memory matching the size requirement (no alignment constraint)
639  * @map: The address to base the search on
640  * @size: The bitmap size in bits
641  * @start: The bitnumber to start searching at
642  * @nr: The number of zeroed bits we're looking for
643  * @data: additional data - unused
644  * @pool: pool to find the fit region memory from
645  * @start_addr: not used in this function
646  */
gen_pool_first_fit(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)647 unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
648 		unsigned long start, unsigned int nr, void *data,
649 		struct gen_pool *pool, unsigned long start_addr)
650 {
651 	return bitmap_find_next_zero_area(map, size, start, nr, 0);
652 }
653 EXPORT_SYMBOL(gen_pool_first_fit);
654 
655 /**
656  * gen_pool_first_fit_align - find the first available region
657  * of memory matching the size requirement (alignment constraint)
658  * @map: The address to base the search on
659  * @size: The bitmap size in bits
660  * @start: The bitnumber to start searching at
661  * @nr: The number of zeroed bits we're looking for
662  * @data: data for alignment
663  * @pool: pool to get order from
664  * @start_addr: start addr of alloction chunk
665  */
gen_pool_first_fit_align(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)666 unsigned long gen_pool_first_fit_align(unsigned long *map, unsigned long size,
667 		unsigned long start, unsigned int nr, void *data,
668 		struct gen_pool *pool, unsigned long start_addr)
669 {
670 	struct genpool_data_align *alignment;
671 	unsigned long align_mask, align_off;
672 	int order;
673 
674 	alignment = data;
675 	order = pool->min_alloc_order;
676 	align_mask = ((alignment->align + (1UL << order) - 1) >> order) - 1;
677 	align_off = (start_addr & (alignment->align - 1)) >> order;
678 
679 	return bitmap_find_next_zero_area_off(map, size, start, nr,
680 					      align_mask, align_off);
681 }
682 EXPORT_SYMBOL(gen_pool_first_fit_align);
683 
684 /**
685  * gen_pool_fixed_alloc - reserve a specific region
686  * @map: The address to base the search on
687  * @size: The bitmap size in bits
688  * @start: The bitnumber to start searching at
689  * @nr: The number of zeroed bits we're looking for
690  * @data: data for alignment
691  * @pool: pool to get order from
692  * @start_addr: not used in this function
693  */
gen_pool_fixed_alloc(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)694 unsigned long gen_pool_fixed_alloc(unsigned long *map, unsigned long size,
695 		unsigned long start, unsigned int nr, void *data,
696 		struct gen_pool *pool, unsigned long start_addr)
697 {
698 	struct genpool_data_fixed *fixed_data;
699 	int order;
700 	unsigned long offset_bit;
701 	unsigned long start_bit;
702 
703 	fixed_data = data;
704 	order = pool->min_alloc_order;
705 	offset_bit = fixed_data->offset >> order;
706 	if (WARN_ON(fixed_data->offset & ((1UL << order) - 1)))
707 		return size;
708 
709 	start_bit = bitmap_find_next_zero_area(map, size,
710 			start + offset_bit, nr, 0);
711 	if (start_bit != offset_bit)
712 		start_bit = size;
713 	return start_bit;
714 }
715 EXPORT_SYMBOL(gen_pool_fixed_alloc);
716 
717 /**
718  * gen_pool_first_fit_order_align - find the first available region
719  * of memory matching the size requirement. The region will be aligned
720  * to the order of the size specified.
721  * @map: The address to base the search on
722  * @size: The bitmap size in bits
723  * @start: The bitnumber to start searching at
724  * @nr: The number of zeroed bits we're looking for
725  * @data: additional data - unused
726  * @pool: pool to find the fit region memory from
727  * @start_addr: not used in this function
728  */
gen_pool_first_fit_order_align(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)729 unsigned long gen_pool_first_fit_order_align(unsigned long *map,
730 		unsigned long size, unsigned long start,
731 		unsigned int nr, void *data, struct gen_pool *pool,
732 		unsigned long start_addr)
733 {
734 	unsigned long align_mask = roundup_pow_of_two(nr) - 1;
735 
736 	return bitmap_find_next_zero_area(map, size, start, nr, align_mask);
737 }
738 EXPORT_SYMBOL(gen_pool_first_fit_order_align);
739 
740 /**
741  * gen_pool_best_fit - find the best fitting region of memory
742  * matching the size requirement (no alignment constraint)
743  * @map: The address to base the search on
744  * @size: The bitmap size in bits
745  * @start: The bitnumber to start searching at
746  * @nr: The number of zeroed bits we're looking for
747  * @data: additional data - unused
748  * @pool: pool to find the fit region memory from
749  * @start_addr: not used in this function
750  *
751  * Iterate over the bitmap to find the smallest free region
752  * which we can allocate the memory.
753  */
gen_pool_best_fit(unsigned long * map,unsigned long size,unsigned long start,unsigned int nr,void * data,struct gen_pool * pool,unsigned long start_addr)754 unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
755 		unsigned long start, unsigned int nr, void *data,
756 		struct gen_pool *pool, unsigned long start_addr)
757 {
758 	unsigned long start_bit = size;
759 	unsigned long len = size + 1;
760 	unsigned long index;
761 
762 	index = bitmap_find_next_zero_area(map, size, start, nr, 0);
763 
764 	while (index < size) {
765 		unsigned long next_bit = find_next_bit(map, size, index + nr);
766 		if ((next_bit - index) < len) {
767 			len = next_bit - index;
768 			start_bit = index;
769 			if (len == nr)
770 				return start_bit;
771 		}
772 		index = bitmap_find_next_zero_area(map, size,
773 						   next_bit + 1, nr, 0);
774 	}
775 
776 	return start_bit;
777 }
778 EXPORT_SYMBOL(gen_pool_best_fit);
779 
devm_gen_pool_release(struct device * dev,void * res)780 static void devm_gen_pool_release(struct device *dev, void *res)
781 {
782 	gen_pool_destroy(*(struct gen_pool **)res);
783 }
784 
devm_gen_pool_match(struct device * dev,void * res,void * data)785 static int devm_gen_pool_match(struct device *dev, void *res, void *data)
786 {
787 	struct gen_pool **p = res;
788 
789 	/* NULL data matches only a pool without an assigned name */
790 	if (!data && !(*p)->name)
791 		return 1;
792 
793 	if (!data || !(*p)->name)
794 		return 0;
795 
796 	return !strcmp((*p)->name, data);
797 }
798 
799 /**
800  * gen_pool_get - Obtain the gen_pool (if any) for a device
801  * @dev: device to retrieve the gen_pool from
802  * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
803  *
804  * Returns the gen_pool for the device if one is present, or NULL.
805  */
gen_pool_get(struct device * dev,const char * name)806 struct gen_pool *gen_pool_get(struct device *dev, const char *name)
807 {
808 	struct gen_pool **p;
809 
810 	p = devres_find(dev, devm_gen_pool_release, devm_gen_pool_match,
811 			(void *)name);
812 	if (!p)
813 		return NULL;
814 	return *p;
815 }
816 EXPORT_SYMBOL_GPL(gen_pool_get);
817 
818 /**
819  * devm_gen_pool_create - managed gen_pool_create
820  * @dev: device that provides the gen_pool
821  * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
822  * @nid: node selector for allocated gen_pool, %NUMA_NO_NODE for all nodes
823  * @name: name of a gen_pool or NULL, identifies a particular gen_pool on device
824  *
825  * Create a new special memory pool that can be used to manage special purpose
826  * memory not managed by the regular kmalloc/kfree interface. The pool will be
827  * automatically destroyed by the device management code.
828  */
devm_gen_pool_create(struct device * dev,int min_alloc_order,int nid,const char * name)829 struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
830 				      int nid, const char *name)
831 {
832 	struct gen_pool **ptr, *pool;
833 	const char *pool_name = NULL;
834 
835 	/* Check that genpool to be created is uniquely addressed on device */
836 	if (gen_pool_get(dev, name))
837 		return ERR_PTR(-EINVAL);
838 
839 	if (name) {
840 		pool_name = kstrdup_const(name, GFP_KERNEL);
841 		if (!pool_name)
842 			return ERR_PTR(-ENOMEM);
843 	}
844 
845 	ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
846 	if (!ptr)
847 		goto free_pool_name;
848 
849 	pool = gen_pool_create(min_alloc_order, nid);
850 	if (!pool)
851 		goto free_devres;
852 
853 	*ptr = pool;
854 	pool->name = pool_name;
855 	devres_add(dev, ptr);
856 
857 	return pool;
858 
859 free_devres:
860 	devres_free(ptr);
861 free_pool_name:
862 	kfree_const(pool_name);
863 
864 	return ERR_PTR(-ENOMEM);
865 }
866 EXPORT_SYMBOL(devm_gen_pool_create);
867 
868 #ifdef CONFIG_OF
869 /**
870  * of_gen_pool_get - find a pool by phandle property
871  * @np: device node
872  * @propname: property name containing phandle(s)
873  * @index: index into the phandle array
874  *
875  * Returns the pool that contains the chunk starting at the physical
876  * address of the device tree node pointed at by the phandle property,
877  * or NULL if not found.
878  */
of_gen_pool_get(struct device_node * np,const char * propname,int index)879 struct gen_pool *of_gen_pool_get(struct device_node *np,
880 	const char *propname, int index)
881 {
882 	struct platform_device *pdev;
883 	struct device_node *np_pool, *parent;
884 	const char *name = NULL;
885 	struct gen_pool *pool = NULL;
886 
887 	np_pool = of_parse_phandle(np, propname, index);
888 	if (!np_pool)
889 		return NULL;
890 
891 	pdev = of_find_device_by_node(np_pool);
892 	if (!pdev) {
893 		/* Check if named gen_pool is created by parent node device */
894 		parent = of_get_parent(np_pool);
895 		pdev = of_find_device_by_node(parent);
896 		of_node_put(parent);
897 
898 		of_property_read_string(np_pool, "label", &name);
899 		if (!name)
900 			name = of_node_full_name(np_pool);
901 	}
902 	if (pdev)
903 		pool = gen_pool_get(&pdev->dev, name);
904 	of_node_put(np_pool);
905 
906 	return pool;
907 }
908 EXPORT_SYMBOL_GPL(of_gen_pool_get);
909 #endif /* CONFIG_OF */
910