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Joonsoo Kima2541292014-08-06 16:05:25 -07001/*
2 * Contiguous Memory Allocator
3 *
4 * Copyright (c) 2010-2011 by Samsung Electronics.
5 * Copyright IBM Corporation, 2013
6 * Copyright LG Electronics Inc., 2014
7 * Written by:
8 * Marek Szyprowski <m.szyprowski@samsung.com>
9 * Michal Nazarewicz <mina86@mina86.com>
10 * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
11 * Joonsoo Kim <iamjoonsoo.kim@lge.com>
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License as
15 * published by the Free Software Foundation; either version 2 of the
16 * License or (at your optional) any later version of the license.
17 */
18
19#define pr_fmt(fmt) "cma: " fmt
20
21#ifdef CONFIG_CMA_DEBUG
22#ifndef DEBUG
23# define DEBUG
24#endif
25#endif
26
27#include <linux/memblock.h>
28#include <linux/err.h>
29#include <linux/mm.h>
30#include <linux/mutex.h>
31#include <linux/sizes.h>
32#include <linux/slab.h>
33#include <linux/log2.h>
34#include <linux/cma.h>
Marek Szyprowskif7426b92014-10-09 15:26:47 -070035#include <linux/highmem.h>
Joonsoo Kima2541292014-08-06 16:05:25 -070036
37struct cma {
38 unsigned long base_pfn;
39 unsigned long count;
40 unsigned long *bitmap;
41 unsigned int order_per_bit; /* Order of pages represented by one bit */
42 struct mutex lock;
43};
44
45static struct cma cma_areas[MAX_CMA_AREAS];
46static unsigned cma_area_count;
47static DEFINE_MUTEX(cma_mutex);
48
49phys_addr_t cma_get_base(struct cma *cma)
50{
51 return PFN_PHYS(cma->base_pfn);
52}
53
54unsigned long cma_get_size(struct cma *cma)
55{
56 return cma->count << PAGE_SHIFT;
57}
58
59static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
60{
Weijie Yang68faed62014-10-13 15:51:03 -070061 if (align_order <= cma->order_per_bit)
62 return 0;
63 return (1UL << (align_order - cma->order_per_bit)) - 1;
Joonsoo Kima2541292014-08-06 16:05:25 -070064}
65
66static unsigned long cma_bitmap_maxno(struct cma *cma)
67{
68 return cma->count >> cma->order_per_bit;
69}
70
71static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
72 unsigned long pages)
73{
74 return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
75}
76
77static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
78{
79 unsigned long bitmap_no, bitmap_count;
80
81 bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
82 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
83
84 mutex_lock(&cma->lock);
85 bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
86 mutex_unlock(&cma->lock);
87}
88
89static int __init cma_activate_area(struct cma *cma)
90{
91 int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
92 unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
93 unsigned i = cma->count >> pageblock_order;
94 struct zone *zone;
95
96 cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
97
98 if (!cma->bitmap)
99 return -ENOMEM;
100
101 WARN_ON_ONCE(!pfn_valid(pfn));
102 zone = page_zone(pfn_to_page(pfn));
103
104 do {
105 unsigned j;
106
107 base_pfn = pfn;
108 for (j = pageblock_nr_pages; j; --j, pfn++) {
109 WARN_ON_ONCE(!pfn_valid(pfn));
110 /*
111 * alloc_contig_range requires the pfn range
112 * specified to be in the same zone. Make this
113 * simple by forcing the entire CMA resv range
114 * to be in the same zone.
115 */
116 if (page_zone(pfn_to_page(pfn)) != zone)
117 goto err;
118 }
119 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
120 } while (--i);
121
122 mutex_init(&cma->lock);
123 return 0;
124
125err:
126 kfree(cma->bitmap);
127 return -EINVAL;
128}
129
130static int __init cma_init_reserved_areas(void)
131{
132 int i;
133
134 for (i = 0; i < cma_area_count; i++) {
135 int ret = cma_activate_area(&cma_areas[i]);
136
137 if (ret)
138 return ret;
139 }
140
141 return 0;
142}
143core_initcall(cma_init_reserved_areas);
144
145/**
Marek Szyprowskide9e14e2014-10-13 15:51:09 -0700146 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
147 * @base: Base address of the reserved area
148 * @size: Size of the reserved area (in bytes),
149 * @order_per_bit: Order of pages represented by one bit on bitmap.
150 * @res_cma: Pointer to store the created cma region.
151 *
152 * This function creates custom contiguous area from already reserved memory.
153 */
154int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
155 int order_per_bit, struct cma **res_cma)
156{
157 struct cma *cma;
158 phys_addr_t alignment;
159
160 /* Sanity checks */
161 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
162 pr_err("Not enough slots for CMA reserved regions!\n");
163 return -ENOSPC;
164 }
165
166 if (!size || !memblock_is_region_reserved(base, size))
167 return -EINVAL;
168
169 /* ensure minimal alignment requied by mm core */
170 alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
171
172 /* alignment should be aligned with order_per_bit */
173 if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
174 return -EINVAL;
175
176 if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
177 return -EINVAL;
178
179 /*
180 * Each reserved area must be initialised later, when more kernel
181 * subsystems (like slab allocator) are available.
182 */
183 cma = &cma_areas[cma_area_count];
184 cma->base_pfn = PFN_DOWN(base);
185 cma->count = size >> PAGE_SHIFT;
186 cma->order_per_bit = order_per_bit;
187 *res_cma = cma;
188 cma_area_count++;
189
190 return 0;
191}
192
193/**
Joonsoo Kima2541292014-08-06 16:05:25 -0700194 * cma_declare_contiguous() - reserve custom contiguous area
Joonsoo Kima2541292014-08-06 16:05:25 -0700195 * @base: Base address of the reserved area optional, use 0 for any
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700196 * @size: Size of the reserved area (in bytes),
Joonsoo Kima2541292014-08-06 16:05:25 -0700197 * @limit: End address of the reserved memory (optional, 0 for any).
198 * @alignment: Alignment for the CMA area, should be power of 2 or zero
199 * @order_per_bit: Order of pages represented by one bit on bitmap.
Joonsoo Kima2541292014-08-06 16:05:25 -0700200 * @fixed: hint about where to place the reserved area
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700201 * @res_cma: Pointer to store the created cma region.
Joonsoo Kima2541292014-08-06 16:05:25 -0700202 *
203 * This function reserves memory from early allocator. It should be
204 * called by arch specific code once the early allocator (memblock or bootmem)
205 * has been activated and all other subsystems have already allocated/reserved
206 * memory. This function allows to create custom reserved areas.
207 *
208 * If @fixed is true, reserve contiguous area at exactly @base. If false,
209 * reserve in range from @base to @limit.
210 */
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700211int __init cma_declare_contiguous(phys_addr_t base,
212 phys_addr_t size, phys_addr_t limit,
Joonsoo Kima2541292014-08-06 16:05:25 -0700213 phys_addr_t alignment, unsigned int order_per_bit,
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700214 bool fixed, struct cma **res_cma)
Joonsoo Kima2541292014-08-06 16:05:25 -0700215{
Marek Szyprowskif7426b92014-10-09 15:26:47 -0700216 phys_addr_t memblock_end = memblock_end_of_DRAM();
217 phys_addr_t highmem_start = __pa(high_memory);
Joonsoo Kima2541292014-08-06 16:05:25 -0700218 int ret = 0;
219
220 pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
221 __func__, (unsigned long)size, (unsigned long)base,
222 (unsigned long)limit, (unsigned long)alignment);
223
224 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
225 pr_err("Not enough slots for CMA reserved regions!\n");
226 return -ENOSPC;
227 }
228
229 if (!size)
230 return -EINVAL;
231
232 if (alignment && !is_power_of_2(alignment))
233 return -EINVAL;
234
235 /*
236 * Sanitise input arguments.
237 * Pages both ends in CMA area could be merged into adjacent unmovable
238 * migratetype page by page allocator's buddy algorithm. In the case,
239 * you couldn't get a contiguous memory, which is not what we want.
240 */
241 alignment = max(alignment,
242 (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
243 base = ALIGN(base, alignment);
244 size = ALIGN(size, alignment);
245 limit &= ~(alignment - 1);
246
247 /* size should be aligned with order_per_bit */
248 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
249 return -EINVAL;
250
Marek Szyprowskif7426b92014-10-09 15:26:47 -0700251 /*
252 * adjust limit to avoid crossing low/high memory boundary for
253 * automatically allocated regions
254 */
255 if (((limit == 0 || limit > memblock_end) &&
256 (memblock_end - size < highmem_start &&
257 memblock_end > highmem_start)) ||
258 (!fixed && limit > highmem_start && limit - size < highmem_start)) {
259 limit = highmem_start;
260 }
261
262 if (fixed && base < highmem_start && base+size > highmem_start) {
263 ret = -EINVAL;
264 pr_err("Region at %08lx defined on low/high memory boundary (%08lx)\n",
265 (unsigned long)base, (unsigned long)highmem_start);
266 goto err;
267 }
268
Joonsoo Kima2541292014-08-06 16:05:25 -0700269 /* Reserve memory */
270 if (base && fixed) {
271 if (memblock_is_region_reserved(base, size) ||
272 memblock_reserve(base, size) < 0) {
273 ret = -EBUSY;
274 goto err;
275 }
276 } else {
277 phys_addr_t addr = memblock_alloc_range(size, alignment, base,
278 limit);
279 if (!addr) {
280 ret = -ENOMEM;
281 goto err;
282 } else {
283 base = addr;
284 }
285 }
286
Marek Szyprowskide9e14e2014-10-13 15:51:09 -0700287 ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
288 if (ret)
289 goto err;
Joonsoo Kima2541292014-08-06 16:05:25 -0700290
Joonsoo Kim0de9d2e2014-08-06 16:05:34 -0700291 pr_info("Reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
Joonsoo Kima2541292014-08-06 16:05:25 -0700292 (unsigned long)base);
293 return 0;
294
295err:
Joonsoo Kim0de9d2e2014-08-06 16:05:34 -0700296 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
Joonsoo Kima2541292014-08-06 16:05:25 -0700297 return ret;
298}
299
300/**
301 * cma_alloc() - allocate pages from contiguous area
302 * @cma: Contiguous memory region for which the allocation is performed.
303 * @count: Requested number of pages.
304 * @align: Requested alignment of pages (in PAGE_SIZE order).
305 *
306 * This function allocates part of contiguous memory on specific
307 * contiguous memory area.
308 */
309struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
310{
311 unsigned long mask, pfn, start = 0;
312 unsigned long bitmap_maxno, bitmap_no, bitmap_count;
313 struct page *page = NULL;
314 int ret;
315
316 if (!cma || !cma->count)
317 return NULL;
318
319 pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
320 count, align);
321
322 if (!count)
323 return NULL;
324
325 mask = cma_bitmap_aligned_mask(cma, align);
326 bitmap_maxno = cma_bitmap_maxno(cma);
327 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
328
329 for (;;) {
330 mutex_lock(&cma->lock);
331 bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
332 bitmap_maxno, start, bitmap_count, mask);
333 if (bitmap_no >= bitmap_maxno) {
334 mutex_unlock(&cma->lock);
335 break;
336 }
337 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
338 /*
339 * It's safe to drop the lock here. We've marked this region for
340 * our exclusive use. If the migration fails we will take the
341 * lock again and unmark it.
342 */
343 mutex_unlock(&cma->lock);
344
345 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
346 mutex_lock(&cma_mutex);
347 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
348 mutex_unlock(&cma_mutex);
349 if (ret == 0) {
350 page = pfn_to_page(pfn);
351 break;
Joonsoo Kima2541292014-08-06 16:05:25 -0700352 }
Joonsoo Kimb7155e72014-08-06 16:05:30 -0700353
Joonsoo Kima2541292014-08-06 16:05:25 -0700354 cma_clear_bitmap(cma, pfn, count);
Joonsoo Kimb7155e72014-08-06 16:05:30 -0700355 if (ret != -EBUSY)
356 break;
357
Joonsoo Kima2541292014-08-06 16:05:25 -0700358 pr_debug("%s(): memory range at %p is busy, retrying\n",
359 __func__, pfn_to_page(pfn));
360 /* try again with a bit different memory target */
361 start = bitmap_no + mask + 1;
362 }
363
364 pr_debug("%s(): returned %p\n", __func__, page);
365 return page;
366}
367
368/**
369 * cma_release() - release allocated pages
370 * @cma: Contiguous memory region for which the allocation is performed.
371 * @pages: Allocated pages.
372 * @count: Number of allocated pages.
373 *
374 * This function releases memory allocated by alloc_cma().
375 * It returns false when provided pages do not belong to contiguous area and
376 * true otherwise.
377 */
378bool cma_release(struct cma *cma, struct page *pages, int count)
379{
380 unsigned long pfn;
381
382 if (!cma || !pages)
383 return false;
384
385 pr_debug("%s(page %p)\n", __func__, (void *)pages);
386
387 pfn = page_to_pfn(pages);
388
389 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
390 return false;
391
392 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
393
394 free_contig_range(pfn, count);
395 cma_clear_bitmap(cma, pfn, count);
396
397 return true;
398}