1 /*
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 #define CREATE_TRACE_POINTS
27
28 #include <linux/memblock.h>
29 #include <linux/err.h>
30 #include <linux/mm.h>
31 #include <linux/mutex.h>
32 #include <linux/sizes.h>
33 #include <linux/slab.h>
34 #include <linux/log2.h>
35 #include <linux/cma.h>
36 #include <linux/highmem.h>
37 #include <linux/io.h>
38 #include <trace/events/cma.h>
39
40 #include "cma.h"
41
42 struct cma cma_areas[MAX_CMA_AREAS];
43 unsigned cma_area_count;
44 static DEFINE_MUTEX(cma_mutex);
45
cma_get_base(const struct cma * cma)46 phys_addr_t cma_get_base(const struct cma *cma)
47 {
48 return PFN_PHYS(cma->base_pfn);
49 }
50
cma_get_size(const struct cma * cma)51 unsigned long cma_get_size(const struct cma *cma)
52 {
53 return cma->count << PAGE_SHIFT;
54 }
55
cma_bitmap_aligned_mask(const struct cma * cma,unsigned int align_order)56 static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
57 unsigned int align_order)
58 {
59 if (align_order <= cma->order_per_bit)
60 return 0;
61 return (1UL << (align_order - cma->order_per_bit)) - 1;
62 }
63
64 /*
65 * Find the offset of the base PFN from the specified align_order.
66 * The value returned is represented in order_per_bits.
67 */
cma_bitmap_aligned_offset(const struct cma * cma,unsigned int align_order)68 static unsigned long cma_bitmap_aligned_offset(const struct cma *cma,
69 unsigned int align_order)
70 {
71 return (cma->base_pfn & ((1UL << align_order) - 1))
72 >> cma->order_per_bit;
73 }
74
cma_bitmap_pages_to_bits(const struct cma * cma,unsigned long pages)75 static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma,
76 unsigned long pages)
77 {
78 return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
79 }
80
cma_clear_bitmap(struct cma * cma,unsigned long pfn,unsigned int count)81 static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
82 unsigned int count)
83 {
84 unsigned long bitmap_no, bitmap_count;
85
86 bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
87 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
88
89 mutex_lock(&cma->lock);
90 bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
91 mutex_unlock(&cma->lock);
92 }
93
cma_activate_area(struct cma * cma)94 static int __init cma_activate_area(struct cma *cma)
95 {
96 int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
97 unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
98 unsigned i = cma->count >> pageblock_order;
99 struct zone *zone;
100
101 cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
102
103 if (!cma->bitmap)
104 return -ENOMEM;
105
106 WARN_ON_ONCE(!pfn_valid(pfn));
107 zone = page_zone(pfn_to_page(pfn));
108
109 do {
110 unsigned j;
111
112 base_pfn = pfn;
113 for (j = pageblock_nr_pages; j; --j, pfn++) {
114 WARN_ON_ONCE(!pfn_valid(pfn));
115 /*
116 * alloc_contig_range requires the pfn range
117 * specified to be in the same zone. Make this
118 * simple by forcing the entire CMA resv range
119 * to be in the same zone.
120 */
121 if (page_zone(pfn_to_page(pfn)) != zone)
122 goto err;
123 }
124 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
125 } while (--i);
126
127 mutex_init(&cma->lock);
128
129 #ifdef CONFIG_CMA_DEBUGFS
130 INIT_HLIST_HEAD(&cma->mem_head);
131 spin_lock_init(&cma->mem_head_lock);
132 #endif
133
134 return 0;
135
136 err:
137 kfree(cma->bitmap);
138 cma->count = 0;
139 return -EINVAL;
140 }
141
cma_init_reserved_areas(void)142 static int __init cma_init_reserved_areas(void)
143 {
144 int i;
145
146 for (i = 0; i < cma_area_count; i++) {
147 int ret = cma_activate_area(&cma_areas[i]);
148
149 if (ret)
150 return ret;
151 }
152
153 return 0;
154 }
155 core_initcall(cma_init_reserved_areas);
156
157 /**
158 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
159 * @base: Base address of the reserved area
160 * @size: Size of the reserved area (in bytes),
161 * @order_per_bit: Order of pages represented by one bit on bitmap.
162 * @res_cma: Pointer to store the created cma region.
163 *
164 * This function creates custom contiguous area from already reserved memory.
165 */
cma_init_reserved_mem(phys_addr_t base,phys_addr_t size,unsigned int order_per_bit,struct cma ** res_cma)166 int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
167 unsigned int order_per_bit,
168 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 required by mm core */
183 alignment = PAGE_SIZE <<
184 max_t(unsigned long, MAX_ORDER - 1, pageblock_order);
185
186 /* alignment should be aligned with order_per_bit */
187 if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
188 return -EINVAL;
189
190 if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
191 return -EINVAL;
192
193 /*
194 * Each reserved area must be initialised later, when more kernel
195 * subsystems (like slab allocator) are available.
196 */
197 cma = &cma_areas[cma_area_count];
198 cma->base_pfn = PFN_DOWN(base);
199 cma->count = size >> PAGE_SHIFT;
200 cma->order_per_bit = order_per_bit;
201 *res_cma = cma;
202 cma_area_count++;
203 totalcma_pages += (size / PAGE_SIZE);
204
205 return 0;
206 }
207
208 /**
209 * cma_declare_contiguous() - reserve custom contiguous area
210 * @base: Base address of the reserved area optional, use 0 for any
211 * @size: Size of the reserved area (in bytes),
212 * @limit: End address of the reserved memory (optional, 0 for any).
213 * @alignment: Alignment for the CMA area, should be power of 2 or zero
214 * @order_per_bit: Order of pages represented by one bit on bitmap.
215 * @fixed: hint about where to place the reserved area
216 * @res_cma: Pointer to store the created cma region.
217 *
218 * This function reserves memory from early allocator. It should be
219 * called by arch specific code once the early allocator (memblock or bootmem)
220 * has been activated and all other subsystems have already allocated/reserved
221 * memory. This function allows to create custom reserved areas.
222 *
223 * If @fixed is true, reserve contiguous area at exactly @base. If false,
224 * reserve in range from @base to @limit.
225 */
cma_declare_contiguous(phys_addr_t base,phys_addr_t size,phys_addr_t limit,phys_addr_t alignment,unsigned int order_per_bit,bool fixed,struct cma ** res_cma)226 int __init cma_declare_contiguous(phys_addr_t base,
227 phys_addr_t size, phys_addr_t limit,
228 phys_addr_t alignment, unsigned int order_per_bit,
229 bool fixed, struct cma **res_cma)
230 {
231 phys_addr_t memblock_end = memblock_end_of_DRAM();
232 phys_addr_t highmem_start;
233 int ret = 0;
234
235 #ifdef CONFIG_X86
236 /*
237 * high_memory isn't direct mapped memory so retrieving its physical
238 * address isn't appropriate. But it would be useful to check the
239 * physical address of the highmem boundary so it's justifiable to get
240 * the physical address from it. On x86 there is a validation check for
241 * this case, so the following workaround is needed to avoid it.
242 */
243 highmem_start = __pa_nodebug(high_memory);
244 #else
245 highmem_start = __pa(high_memory);
246 #endif
247 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
248 __func__, &size, &base, &limit, &alignment);
249
250 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
251 pr_err("Not enough slots for CMA reserved regions!\n");
252 return -ENOSPC;
253 }
254
255 if (!size)
256 return -EINVAL;
257
258 if (alignment && !is_power_of_2(alignment))
259 return -EINVAL;
260
261 /*
262 * Sanitise input arguments.
263 * Pages both ends in CMA area could be merged into adjacent unmovable
264 * migratetype page by page allocator's buddy algorithm. In the case,
265 * you couldn't get a contiguous memory, which is not what we want.
266 */
267 alignment = max(alignment, (phys_addr_t)PAGE_SIZE <<
268 max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
269 base = ALIGN(base, alignment);
270 size = ALIGN(size, alignment);
271 limit &= ~(alignment - 1);
272
273 if (!base)
274 fixed = false;
275
276 /* size should be aligned with order_per_bit */
277 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
278 return -EINVAL;
279
280 /*
281 * If allocating at a fixed base the request region must not cross the
282 * low/high memory boundary.
283 */
284 if (fixed && base < highmem_start && base + size > highmem_start) {
285 ret = -EINVAL;
286 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
287 &base, &highmem_start);
288 goto err;
289 }
290
291 /*
292 * If the limit is unspecified or above the memblock end, its effective
293 * value will be the memblock end. Set it explicitly to simplify further
294 * checks.
295 */
296 if (limit == 0 || limit > memblock_end)
297 limit = memblock_end;
298
299 /* Reserve memory */
300 if (fixed) {
301 if (memblock_is_region_reserved(base, size) ||
302 memblock_reserve(base, size) < 0) {
303 ret = -EBUSY;
304 goto err;
305 }
306 } else {
307 phys_addr_t addr = 0;
308
309 /*
310 * All pages in the reserved area must come from the same zone.
311 * If the requested region crosses the low/high memory boundary,
312 * try allocating from high memory first and fall back to low
313 * memory in case of failure.
314 */
315 if (base < highmem_start && limit > highmem_start) {
316 addr = memblock_alloc_range(size, alignment,
317 highmem_start, limit,
318 MEMBLOCK_NONE);
319 limit = highmem_start;
320 }
321
322 if (!addr) {
323 addr = memblock_alloc_range(size, alignment, base,
324 limit,
325 MEMBLOCK_NONE);
326 if (!addr) {
327 ret = -ENOMEM;
328 goto err;
329 }
330 }
331
332 /*
333 * kmemleak scans/reads tracked objects for pointers to other
334 * objects but this address isn't mapped and accessible
335 */
336 kmemleak_ignore_phys(addr);
337 base = addr;
338 }
339
340 ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
341 if (ret)
342 goto err;
343
344 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
345 &base);
346 return 0;
347
348 err:
349 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
350 return ret;
351 }
352
353 /**
354 * cma_alloc() - allocate pages from contiguous area
355 * @cma: Contiguous memory region for which the allocation is performed.
356 * @count: Requested number of pages.
357 * @align: Requested alignment of pages (in PAGE_SIZE order).
358 *
359 * This function allocates part of contiguous memory on specific
360 * contiguous memory area.
361 */
cma_alloc(struct cma * cma,size_t count,unsigned int align)362 struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
363 {
364 unsigned long mask, offset;
365 unsigned long pfn = -1;
366 unsigned long start = 0;
367 unsigned long bitmap_maxno, bitmap_no, bitmap_count;
368 struct page *page = NULL;
369 int ret;
370
371 if (!cma || !cma->count)
372 return NULL;
373
374 pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
375 count, align);
376
377 if (!count)
378 return NULL;
379
380 mask = cma_bitmap_aligned_mask(cma, align);
381 offset = cma_bitmap_aligned_offset(cma, align);
382 bitmap_maxno = cma_bitmap_maxno(cma);
383 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
384
385 if (bitmap_count > bitmap_maxno)
386 return NULL;
387
388 for (;;) {
389 mutex_lock(&cma->lock);
390 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
391 bitmap_maxno, start, bitmap_count, mask,
392 offset);
393 if (bitmap_no >= bitmap_maxno) {
394 mutex_unlock(&cma->lock);
395 break;
396 }
397 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
398 /*
399 * It's safe to drop the lock here. We've marked this region for
400 * our exclusive use. If the migration fails we will take the
401 * lock again and unmark it.
402 */
403 mutex_unlock(&cma->lock);
404
405 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
406 mutex_lock(&cma_mutex);
407 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
408 mutex_unlock(&cma_mutex);
409 if (ret == 0) {
410 page = pfn_to_page(pfn);
411 break;
412 }
413
414 cma_clear_bitmap(cma, pfn, count);
415 if (ret != -EBUSY)
416 break;
417
418 pr_debug("%s(): memory range at %p is busy, retrying\n",
419 __func__, pfn_to_page(pfn));
420 /* try again with a bit different memory target */
421 start = bitmap_no + mask + 1;
422 }
423
424 trace_cma_alloc(pfn, page, count, align);
425
426 pr_debug("%s(): returned %p\n", __func__, page);
427 return page;
428 }
429
430 /**
431 * cma_release() - release allocated pages
432 * @cma: Contiguous memory region for which the allocation is performed.
433 * @pages: Allocated pages.
434 * @count: Number of allocated pages.
435 *
436 * This function releases memory allocated by alloc_cma().
437 * It returns false when provided pages do not belong to contiguous area and
438 * true otherwise.
439 */
cma_release(struct cma * cma,const struct page * pages,unsigned int count)440 bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
441 {
442 unsigned long pfn;
443
444 if (!cma || !pages)
445 return false;
446
447 pr_debug("%s(page %p)\n", __func__, (void *)pages);
448
449 pfn = page_to_pfn(pages);
450
451 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
452 return false;
453
454 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
455
456 free_contig_range(pfn, count);
457 cma_clear_bitmap(cma, pfn, count);
458 trace_cma_release(pfn, pages, count);
459
460 return true;
461 }
462