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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>
Thierry Reding620951e2014-12-12 16:58:31 -080036#include <linux/io.h>
Joonsoo Kima2541292014-08-06 16:05:25 -070037
38struct cma {
39 unsigned long base_pfn;
40 unsigned long count;
41 unsigned long *bitmap;
42 unsigned int order_per_bit; /* Order of pages represented by one bit */
43 struct mutex lock;
44};
45
46static struct cma cma_areas[MAX_CMA_AREAS];
47static unsigned cma_area_count;
48static DEFINE_MUTEX(cma_mutex);
49
50phys_addr_t cma_get_base(struct cma *cma)
51{
52 return PFN_PHYS(cma->base_pfn);
53}
54
55unsigned long cma_get_size(struct cma *cma)
56{
57 return cma->count << PAGE_SHIFT;
58}
59
60static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
61{
Weijie Yang68faed62014-10-13 15:51:03 -070062 if (align_order <= cma->order_per_bit)
63 return 0;
64 return (1UL << (align_order - cma->order_per_bit)) - 1;
Joonsoo Kima2541292014-08-06 16:05:25 -070065}
66
Gregory Fongb5be83e2014-12-12 16:54:48 -080067static unsigned long cma_bitmap_aligned_offset(struct cma *cma, int align_order)
68{
69 unsigned int alignment;
70
71 if (align_order <= cma->order_per_bit)
72 return 0;
73 alignment = 1UL << (align_order - cma->order_per_bit);
74 return ALIGN(cma->base_pfn, alignment) -
75 (cma->base_pfn >> cma->order_per_bit);
76}
77
Joonsoo Kima2541292014-08-06 16:05:25 -070078static unsigned long cma_bitmap_maxno(struct cma *cma)
79{
80 return cma->count >> cma->order_per_bit;
81}
82
83static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
84 unsigned long pages)
85{
86 return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
87}
88
89static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
90{
91 unsigned long bitmap_no, bitmap_count;
92
93 bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
94 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
95
96 mutex_lock(&cma->lock);
97 bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
98 mutex_unlock(&cma->lock);
99}
100
101static int __init cma_activate_area(struct cma *cma)
102{
103 int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
104 unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
105 unsigned i = cma->count >> pageblock_order;
106 struct zone *zone;
107
108 cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
109
110 if (!cma->bitmap)
111 return -ENOMEM;
112
113 WARN_ON_ONCE(!pfn_valid(pfn));
114 zone = page_zone(pfn_to_page(pfn));
115
116 do {
117 unsigned j;
118
119 base_pfn = pfn;
120 for (j = pageblock_nr_pages; j; --j, pfn++) {
121 WARN_ON_ONCE(!pfn_valid(pfn));
122 /*
123 * alloc_contig_range requires the pfn range
124 * specified to be in the same zone. Make this
125 * simple by forcing the entire CMA resv range
126 * to be in the same zone.
127 */
128 if (page_zone(pfn_to_page(pfn)) != zone)
129 goto err;
130 }
131 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
132 } while (--i);
133
134 mutex_init(&cma->lock);
135 return 0;
136
137err:
138 kfree(cma->bitmap);
Laurent Pinchartf022d8c2014-10-24 13:18:39 +0300139 cma->count = 0;
Joonsoo Kima2541292014-08-06 16:05:25 -0700140 return -EINVAL;
141}
142
143static int __init cma_init_reserved_areas(void)
144{
145 int i;
146
147 for (i = 0; i < cma_area_count; i++) {
148 int ret = cma_activate_area(&cma_areas[i]);
149
150 if (ret)
151 return ret;
152 }
153
154 return 0;
155}
156core_initcall(cma_init_reserved_areas);
157
158/**
Marek Szyprowskide9e14e2014-10-13 15:51:09 -0700159 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
160 * @base: Base address of the reserved area
161 * @size: Size of the reserved area (in bytes),
162 * @order_per_bit: Order of pages represented by one bit on bitmap.
163 * @res_cma: Pointer to store the created cma region.
164 *
165 * This function creates custom contiguous area from already reserved memory.
166 */
167int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
168 int order_per_bit, struct cma **res_cma)
169{
170 struct cma *cma;
171 phys_addr_t alignment;
172
173 /* Sanity checks */
174 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
175 pr_err("Not enough slots for CMA reserved regions!\n");
176 return -ENOSPC;
177 }
178
179 if (!size || !memblock_is_region_reserved(base, size))
180 return -EINVAL;
181
182 /* ensure minimal alignment requied by mm core */
183 alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
184
185 /* alignment should be aligned with order_per_bit */
186 if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
187 return -EINVAL;
188
189 if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
190 return -EINVAL;
191
192 /*
193 * Each reserved area must be initialised later, when more kernel
194 * subsystems (like slab allocator) are available.
195 */
196 cma = &cma_areas[cma_area_count];
197 cma->base_pfn = PFN_DOWN(base);
198 cma->count = size >> PAGE_SHIFT;
199 cma->order_per_bit = order_per_bit;
200 *res_cma = cma;
201 cma_area_count++;
202
203 return 0;
204}
205
206/**
Joonsoo Kima2541292014-08-06 16:05:25 -0700207 * cma_declare_contiguous() - reserve custom contiguous area
Joonsoo Kima2541292014-08-06 16:05:25 -0700208 * @base: Base address of the reserved area optional, use 0 for any
Joonsoo Kimc1f733a2014-08-06 16:05:32 -0700209 * @size: Size of the reserved area (in bytes),
Joonsoo Kima2541292014-08-06 16:05:25 -0700210 * @limit: End address of the reserved memory (optional, 0 for any).
211 * @alignment: Alignment for the CMA area, should be power of 2 or zero
212 * @order_per_bit: Order of pages represented by one bit on bitmap.
Joonsoo Kima2541292014-08-06 16:05:25 -0700213 * @fixed: hint about where to place the reserved area
Joonsoo Kimc1f733a2014-08-06 16:05:32 -0700214 * @res_cma: Pointer to store the created cma region.
Joonsoo Kima2541292014-08-06 16:05:25 -0700215 *
216 * This function reserves memory from early allocator. It should be
217 * called by arch specific code once the early allocator (memblock or bootmem)
218 * has been activated and all other subsystems have already allocated/reserved
219 * memory. This function allows to create custom reserved areas.
220 *
221 * If @fixed is true, reserve contiguous area at exactly @base. If false,
222 * reserve in range from @base to @limit.
223 */
Joonsoo Kimc1f733a2014-08-06 16:05:32 -0700224int __init cma_declare_contiguous(phys_addr_t base,
225 phys_addr_t size, phys_addr_t limit,
Joonsoo Kima2541292014-08-06 16:05:25 -0700226 phys_addr_t alignment, unsigned int order_per_bit,
Joonsoo Kimc1f733a2014-08-06 16:05:32 -0700227 bool fixed, struct cma **res_cma)
Joonsoo Kima2541292014-08-06 16:05:25 -0700228{
Marek Szyprowskif7426b92014-10-09 15:26:47 -0700229 phys_addr_t memblock_end = memblock_end_of_DRAM();
Joonsoo Kim6b101e22014-12-10 15:41:12 -0800230 phys_addr_t highmem_start;
Joonsoo Kima2541292014-08-06 16:05:25 -0700231 int ret = 0;
232
Joonsoo Kim6b101e22014-12-10 15:41:12 -0800233#ifdef CONFIG_X86
234 /*
235 * high_memory isn't direct mapped memory so retrieving its physical
236 * address isn't appropriate. But it would be useful to check the
237 * physical address of the highmem boundary so it's justfiable to get
238 * the physical address from it. On x86 there is a validation check for
239 * this case, so the following workaround is needed to avoid it.
240 */
241 highmem_start = __pa_nodebug(high_memory);
242#else
243 highmem_start = __pa(high_memory);
244#endif
Laurent Pinchart56fa4f62014-10-24 13:18:42 +0300245 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
246 __func__, &size, &base, &limit, &alignment);
Joonsoo Kima2541292014-08-06 16:05:25 -0700247
248 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
249 pr_err("Not enough slots for CMA reserved regions!\n");
250 return -ENOSPC;
251 }
252
253 if (!size)
254 return -EINVAL;
255
256 if (alignment && !is_power_of_2(alignment))
257 return -EINVAL;
258
259 /*
260 * Sanitise input arguments.
261 * Pages both ends in CMA area could be merged into adjacent unmovable
262 * migratetype page by page allocator's buddy algorithm. In the case,
263 * you couldn't get a contiguous memory, which is not what we want.
264 */
265 alignment = max(alignment,
266 (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
267 base = ALIGN(base, alignment);
268 size = ALIGN(size, alignment);
269 limit &= ~(alignment - 1);
270
Laurent Pinchart800a85d2014-10-24 13:18:40 +0300271 if (!base)
272 fixed = false;
273
Joonsoo Kima2541292014-08-06 16:05:25 -0700274 /* size should be aligned with order_per_bit */
275 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
276 return -EINVAL;
277
Marek Szyprowskif7426b92014-10-09 15:26:47 -0700278 /*
Laurent Pinchart16195dd2014-10-24 13:18:41 +0300279 * If allocating at a fixed base the request region must not cross the
280 * low/high memory boundary.
Marek Szyprowskif7426b92014-10-09 15:26:47 -0700281 */
Laurent Pinchart16195dd2014-10-24 13:18:41 +0300282 if (fixed && base < highmem_start && base + size > highmem_start) {
Marek Szyprowskif7426b92014-10-09 15:26:47 -0700283 ret = -EINVAL;
Laurent Pinchart56fa4f62014-10-24 13:18:42 +0300284 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
285 &base, &highmem_start);
Marek Szyprowskif7426b92014-10-09 15:26:47 -0700286 goto err;
287 }
288
Laurent Pinchart16195dd2014-10-24 13:18:41 +0300289 /*
290 * If the limit is unspecified or above the memblock end, its effective
291 * value will be the memblock end. Set it explicitly to simplify further
292 * checks.
293 */
294 if (limit == 0 || limit > memblock_end)
295 limit = memblock_end;
296
Joonsoo Kima2541292014-08-06 16:05:25 -0700297 /* Reserve memory */
Laurent Pinchart800a85d2014-10-24 13:18:40 +0300298 if (fixed) {
Joonsoo Kima2541292014-08-06 16:05:25 -0700299 if (memblock_is_region_reserved(base, size) ||
300 memblock_reserve(base, size) < 0) {
301 ret = -EBUSY;
302 goto err;
303 }
304 } else {
Laurent Pinchart16195dd2014-10-24 13:18:41 +0300305 phys_addr_t addr = 0;
306
307 /*
308 * All pages in the reserved area must come from the same zone.
309 * If the requested region crosses the low/high memory boundary,
310 * try allocating from high memory first and fall back to low
311 * memory in case of failure.
312 */
313 if (base < highmem_start && limit > highmem_start) {
314 addr = memblock_alloc_range(size, alignment,
315 highmem_start, limit);
316 limit = highmem_start;
Joonsoo Kima2541292014-08-06 16:05:25 -0700317 }
Laurent Pinchart16195dd2014-10-24 13:18:41 +0300318
319 if (!addr) {
320 addr = memblock_alloc_range(size, alignment, base,
321 limit);
322 if (!addr) {
323 ret = -ENOMEM;
324 goto err;
325 }
326 }
327
Thierry Reding620951e2014-12-12 16:58:31 -0800328 /*
329 * kmemleak scans/reads tracked objects for pointers to other
330 * objects but this address isn't mapped and accessible
331 */
332 kmemleak_ignore(phys_to_virt(addr));
Laurent Pinchart16195dd2014-10-24 13:18:41 +0300333 base = addr;
Joonsoo Kima2541292014-08-06 16:05:25 -0700334 }
335
Marek Szyprowskide9e14e2014-10-13 15:51:09 -0700336 ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
337 if (ret)
338 goto err;
Joonsoo Kima2541292014-08-06 16:05:25 -0700339
Pintu Kumare48322a2014-12-18 16:17:15 -0800340 totalcma_pages += (size / PAGE_SIZE);
Laurent Pinchart56fa4f62014-10-24 13:18:42 +0300341 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
342 &base);
Joonsoo Kima2541292014-08-06 16:05:25 -0700343 return 0;
344
345err:
Joonsoo Kim0de9d2e2014-08-06 16:05:34 -0700346 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
Joonsoo Kima2541292014-08-06 16:05:25 -0700347 return ret;
348}
349
350/**
351 * cma_alloc() - allocate pages from contiguous area
352 * @cma: Contiguous memory region for which the allocation is performed.
353 * @count: Requested number of pages.
354 * @align: Requested alignment of pages (in PAGE_SIZE order).
355 *
356 * This function allocates part of contiguous memory on specific
357 * contiguous memory area.
358 */
359struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
360{
Gregory Fongb5be83e2014-12-12 16:54:48 -0800361 unsigned long mask, offset, pfn, start = 0;
Joonsoo Kima2541292014-08-06 16:05:25 -0700362 unsigned long bitmap_maxno, bitmap_no, bitmap_count;
363 struct page *page = NULL;
364 int ret;
365
366 if (!cma || !cma->count)
367 return NULL;
368
369 pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
370 count, align);
371
372 if (!count)
373 return NULL;
374
375 mask = cma_bitmap_aligned_mask(cma, align);
Gregory Fongb5be83e2014-12-12 16:54:48 -0800376 offset = cma_bitmap_aligned_offset(cma, align);
Joonsoo Kima2541292014-08-06 16:05:25 -0700377 bitmap_maxno = cma_bitmap_maxno(cma);
378 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
379
380 for (;;) {
381 mutex_lock(&cma->lock);
Gregory Fongb5be83e2014-12-12 16:54:48 -0800382 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
383 bitmap_maxno, start, bitmap_count, mask,
384 offset);
Joonsoo Kima2541292014-08-06 16:05:25 -0700385 if (bitmap_no >= bitmap_maxno) {
386 mutex_unlock(&cma->lock);
387 break;
388 }
389 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
390 /*
391 * It's safe to drop the lock here. We've marked this region for
392 * our exclusive use. If the migration fails we will take the
393 * lock again and unmark it.
394 */
395 mutex_unlock(&cma->lock);
396
397 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
398 mutex_lock(&cma_mutex);
399 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
400 mutex_unlock(&cma_mutex);
401 if (ret == 0) {
402 page = pfn_to_page(pfn);
403 break;
Joonsoo Kima2541292014-08-06 16:05:25 -0700404 }
Joonsoo Kimb7155e72014-08-06 16:05:30 -0700405
Joonsoo Kima2541292014-08-06 16:05:25 -0700406 cma_clear_bitmap(cma, pfn, count);
Joonsoo Kimb7155e72014-08-06 16:05:30 -0700407 if (ret != -EBUSY)
408 break;
409
Joonsoo Kima2541292014-08-06 16:05:25 -0700410 pr_debug("%s(): memory range at %p is busy, retrying\n",
411 __func__, pfn_to_page(pfn));
412 /* try again with a bit different memory target */
413 start = bitmap_no + mask + 1;
414 }
415
416 pr_debug("%s(): returned %p\n", __func__, page);
417 return page;
418}
419
420/**
421 * cma_release() - release allocated pages
422 * @cma: Contiguous memory region for which the allocation is performed.
423 * @pages: Allocated pages.
424 * @count: Number of allocated pages.
425 *
426 * This function releases memory allocated by alloc_cma().
427 * It returns false when provided pages do not belong to contiguous area and
428 * true otherwise.
429 */
430bool cma_release(struct cma *cma, struct page *pages, int count)
431{
432 unsigned long pfn;
433
434 if (!cma || !pages)
435 return false;
436
437 pr_debug("%s(page %p)\n", __func__, (void *)pages);
438
439 pfn = page_to_pfn(pages);
440
441 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
442 return false;
443
444 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
445
446 free_contig_range(pfn, count);
447 cma_clear_bitmap(cma, pfn, count);
448
449 return true;
450}