blob: 488e50810ed1878b75251fa3beaf0ac0b57d9b4f [file] [log] [blame]
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>
35
36struct cma {
37 unsigned long base_pfn;
38 unsigned long count;
39 unsigned long *bitmap;
40 unsigned int order_per_bit; /* Order of pages represented by one bit */
41 struct mutex lock;
42};
43
44static struct cma cma_areas[MAX_CMA_AREAS];
45static unsigned cma_area_count;
46static DEFINE_MUTEX(cma_mutex);
47
48phys_addr_t cma_get_base(struct cma *cma)
49{
50 return PFN_PHYS(cma->base_pfn);
51}
52
53unsigned long cma_get_size(struct cma *cma)
54{
55 return cma->count << PAGE_SHIFT;
56}
57
58static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
59{
60 return (1UL << (align_order >> cma->order_per_bit)) - 1;
61}
62
63static unsigned long cma_bitmap_maxno(struct cma *cma)
64{
65 return cma->count >> cma->order_per_bit;
66}
67
68static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
69 unsigned long pages)
70{
71 return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
72}
73
74static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
75{
76 unsigned long bitmap_no, bitmap_count;
77
78 bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
79 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
80
81 mutex_lock(&cma->lock);
82 bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
83 mutex_unlock(&cma->lock);
84}
85
86static int __init cma_activate_area(struct cma *cma)
87{
88 int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
89 unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
90 unsigned i = cma->count >> pageblock_order;
91 struct zone *zone;
92
93 cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
94
95 if (!cma->bitmap)
96 return -ENOMEM;
97
98 WARN_ON_ONCE(!pfn_valid(pfn));
99 zone = page_zone(pfn_to_page(pfn));
100
101 do {
102 unsigned j;
103
104 base_pfn = pfn;
105 for (j = pageblock_nr_pages; j; --j, pfn++) {
106 WARN_ON_ONCE(!pfn_valid(pfn));
107 /*
108 * alloc_contig_range requires the pfn range
109 * specified to be in the same zone. Make this
110 * simple by forcing the entire CMA resv range
111 * to be in the same zone.
112 */
113 if (page_zone(pfn_to_page(pfn)) != zone)
114 goto err;
115 }
116 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
117 } while (--i);
118
119 mutex_init(&cma->lock);
120 return 0;
121
122err:
123 kfree(cma->bitmap);
124 return -EINVAL;
125}
126
127static int __init cma_init_reserved_areas(void)
128{
129 int i;
130
131 for (i = 0; i < cma_area_count; i++) {
132 int ret = cma_activate_area(&cma_areas[i]);
133
134 if (ret)
135 return ret;
136 }
137
138 return 0;
139}
140core_initcall(cma_init_reserved_areas);
141
142/**
143 * cma_declare_contiguous() - reserve custom contiguous area
Joonsoo Kima2541292014-08-06 16:05:25 -0700144 * @base: Base address of the reserved area optional, use 0 for any
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700145 * @size: Size of the reserved area (in bytes),
Joonsoo Kima2541292014-08-06 16:05:25 -0700146 * @limit: End address of the reserved memory (optional, 0 for any).
147 * @alignment: Alignment for the CMA area, should be power of 2 or zero
148 * @order_per_bit: Order of pages represented by one bit on bitmap.
Joonsoo Kima2541292014-08-06 16:05:25 -0700149 * @fixed: hint about where to place the reserved area
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700150 * @res_cma: Pointer to store the created cma region.
Joonsoo Kima2541292014-08-06 16:05:25 -0700151 *
152 * This function reserves memory from early allocator. It should be
153 * called by arch specific code once the early allocator (memblock or bootmem)
154 * has been activated and all other subsystems have already allocated/reserved
155 * memory. This function allows to create custom reserved areas.
156 *
157 * If @fixed is true, reserve contiguous area at exactly @base. If false,
158 * reserve in range from @base to @limit.
159 */
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700160int __init cma_declare_contiguous(phys_addr_t base,
161 phys_addr_t size, phys_addr_t limit,
Joonsoo Kima2541292014-08-06 16:05:25 -0700162 phys_addr_t alignment, unsigned int order_per_bit,
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700163 bool fixed, struct cma **res_cma)
Joonsoo Kima2541292014-08-06 16:05:25 -0700164{
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700165 struct cma *cma;
Joonsoo Kima2541292014-08-06 16:05:25 -0700166 int ret = 0;
167
168 pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
169 __func__, (unsigned long)size, (unsigned long)base,
170 (unsigned long)limit, (unsigned long)alignment);
171
172 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
173 pr_err("Not enough slots for CMA reserved regions!\n");
174 return -ENOSPC;
175 }
176
177 if (!size)
178 return -EINVAL;
179
180 if (alignment && !is_power_of_2(alignment))
181 return -EINVAL;
182
183 /*
184 * Sanitise input arguments.
185 * Pages both ends in CMA area could be merged into adjacent unmovable
186 * migratetype page by page allocator's buddy algorithm. In the case,
187 * you couldn't get a contiguous memory, which is not what we want.
188 */
189 alignment = max(alignment,
190 (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
191 base = ALIGN(base, alignment);
192 size = ALIGN(size, alignment);
193 limit &= ~(alignment - 1);
194
195 /* size should be aligned with order_per_bit */
196 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
197 return -EINVAL;
198
199 /* Reserve memory */
200 if (base && fixed) {
201 if (memblock_is_region_reserved(base, size) ||
202 memblock_reserve(base, size) < 0) {
203 ret = -EBUSY;
204 goto err;
205 }
206 } else {
207 phys_addr_t addr = memblock_alloc_range(size, alignment, base,
208 limit);
209 if (!addr) {
210 ret = -ENOMEM;
211 goto err;
212 } else {
213 base = addr;
214 }
215 }
216
217 /*
218 * Each reserved area must be initialised later, when more kernel
219 * subsystems (like slab allocator) are available.
220 */
Joonsoo Kimc1f733aa2014-08-06 16:05:32 -0700221 cma = &cma_areas[cma_area_count];
Joonsoo Kima2541292014-08-06 16:05:25 -0700222 cma->base_pfn = PFN_DOWN(base);
223 cma->count = size >> PAGE_SHIFT;
224 cma->order_per_bit = order_per_bit;
225 *res_cma = cma;
226 cma_area_count++;
227
228 pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
229 (unsigned long)base);
230 return 0;
231
232err:
233 pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
234 return ret;
235}
236
237/**
238 * cma_alloc() - allocate pages from contiguous area
239 * @cma: Contiguous memory region for which the allocation is performed.
240 * @count: Requested number of pages.
241 * @align: Requested alignment of pages (in PAGE_SIZE order).
242 *
243 * This function allocates part of contiguous memory on specific
244 * contiguous memory area.
245 */
246struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
247{
248 unsigned long mask, pfn, start = 0;
249 unsigned long bitmap_maxno, bitmap_no, bitmap_count;
250 struct page *page = NULL;
251 int ret;
252
253 if (!cma || !cma->count)
254 return NULL;
255
256 pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
257 count, align);
258
259 if (!count)
260 return NULL;
261
262 mask = cma_bitmap_aligned_mask(cma, align);
263 bitmap_maxno = cma_bitmap_maxno(cma);
264 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
265
266 for (;;) {
267 mutex_lock(&cma->lock);
268 bitmap_no = bitmap_find_next_zero_area(cma->bitmap,
269 bitmap_maxno, start, bitmap_count, mask);
270 if (bitmap_no >= bitmap_maxno) {
271 mutex_unlock(&cma->lock);
272 break;
273 }
274 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
275 /*
276 * It's safe to drop the lock here. We've marked this region for
277 * our exclusive use. If the migration fails we will take the
278 * lock again and unmark it.
279 */
280 mutex_unlock(&cma->lock);
281
282 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
283 mutex_lock(&cma_mutex);
284 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
285 mutex_unlock(&cma_mutex);
286 if (ret == 0) {
287 page = pfn_to_page(pfn);
288 break;
Joonsoo Kima2541292014-08-06 16:05:25 -0700289 }
Joonsoo Kimb7155e72014-08-06 16:05:30 -0700290
Joonsoo Kima2541292014-08-06 16:05:25 -0700291 cma_clear_bitmap(cma, pfn, count);
Joonsoo Kimb7155e72014-08-06 16:05:30 -0700292 if (ret != -EBUSY)
293 break;
294
Joonsoo Kima2541292014-08-06 16:05:25 -0700295 pr_debug("%s(): memory range at %p is busy, retrying\n",
296 __func__, pfn_to_page(pfn));
297 /* try again with a bit different memory target */
298 start = bitmap_no + mask + 1;
299 }
300
301 pr_debug("%s(): returned %p\n", __func__, page);
302 return page;
303}
304
305/**
306 * cma_release() - release allocated pages
307 * @cma: Contiguous memory region for which the allocation is performed.
308 * @pages: Allocated pages.
309 * @count: Number of allocated pages.
310 *
311 * This function releases memory allocated by alloc_cma().
312 * It returns false when provided pages do not belong to contiguous area and
313 * true otherwise.
314 */
315bool cma_release(struct cma *cma, struct page *pages, int count)
316{
317 unsigned long pfn;
318
319 if (!cma || !pages)
320 return false;
321
322 pr_debug("%s(page %p)\n", __func__, (void *)pages);
323
324 pfn = page_to_pfn(pages);
325
326 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
327 return false;
328
329 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
330
331 free_contig_range(pfn, count);
332 cma_clear_bitmap(cma, pfn, count);
333
334 return true;
335}