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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 | ||
46 | phys_addr_t cma_get_base(const struct cma *cma) | |
47 | { | |
48 | return PFN_PHYS(cma->base_pfn); | |
49 | } | |
50 | ||
51 | unsigned long cma_get_size(const struct cma *cma) | |
52 | { | |
53 | return cma->count << PAGE_SHIFT; | |
54 | } | |
55 | ||
56 | static unsigned long cma_bitmap_aligned_mask(const struct cma *cma, | |
57 | 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 a PFN aligned to the specified order and return an offset represented in | |
66 | * order_per_bits. | |
67 | */ | |
68 | static unsigned long cma_bitmap_aligned_offset(const struct cma *cma, | |
69 | int align_order) | |
70 | { | |
71 | if (align_order <= cma->order_per_bit) | |
72 | return 0; | |
73 | ||
74 | return (ALIGN(cma->base_pfn, (1UL << align_order)) | |
75 | - cma->base_pfn) >> cma->order_per_bit; | |
76 | } | |
77 | ||
78 | static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma, | |
79 | unsigned long pages) | |
80 | { | |
81 | return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit; | |
82 | } | |
83 | ||
84 | static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, | |
85 | unsigned int count) | |
86 | { | |
87 | unsigned long bitmap_no, bitmap_count; | |
88 | ||
89 | bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit; | |
90 | bitmap_count = cma_bitmap_pages_to_bits(cma, count); | |
91 | ||
92 | mutex_lock(&cma->lock); | |
93 | bitmap_clear(cma->bitmap, bitmap_no, bitmap_count); | |
94 | mutex_unlock(&cma->lock); | |
95 | } | |
96 | ||
97 | static int __init cma_activate_area(struct cma *cma) | |
98 | { | |
99 | int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long); | |
100 | unsigned long base_pfn = cma->base_pfn, pfn = base_pfn; | |
101 | unsigned i = cma->count >> pageblock_order; | |
102 | struct zone *zone; | |
103 | ||
104 | cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL); | |
105 | ||
106 | if (!cma->bitmap) | |
107 | return -ENOMEM; | |
108 | ||
109 | WARN_ON_ONCE(!pfn_valid(pfn)); | |
110 | zone = page_zone(pfn_to_page(pfn)); | |
111 | ||
112 | do { | |
113 | unsigned j; | |
114 | ||
115 | base_pfn = pfn; | |
116 | for (j = pageblock_nr_pages; j; --j, pfn++) { | |
117 | WARN_ON_ONCE(!pfn_valid(pfn)); | |
118 | /* | |
119 | * alloc_contig_range requires the pfn range | |
120 | * specified to be in the same zone. Make this | |
121 | * simple by forcing the entire CMA resv range | |
122 | * to be in the same zone. | |
123 | */ | |
124 | if (page_zone(pfn_to_page(pfn)) != zone) | |
125 | goto err; | |
126 | } | |
127 | init_cma_reserved_pageblock(pfn_to_page(base_pfn)); | |
128 | } while (--i); | |
129 | ||
130 | mutex_init(&cma->lock); | |
131 | ||
132 | #ifdef CONFIG_CMA_DEBUGFS | |
133 | INIT_HLIST_HEAD(&cma->mem_head); | |
134 | spin_lock_init(&cma->mem_head_lock); | |
135 | #endif | |
136 | ||
137 | return 0; | |
138 | ||
139 | err: | |
140 | kfree(cma->bitmap); | |
141 | cma->count = 0; | |
142 | return -EINVAL; | |
143 | } | |
144 | ||
145 | static int __init cma_init_reserved_areas(void) | |
146 | { | |
147 | int i; | |
148 | ||
149 | for (i = 0; i < cma_area_count; i++) { | |
150 | int ret = cma_activate_area(&cma_areas[i]); | |
151 | ||
152 | if (ret) | |
153 | return ret; | |
154 | } | |
155 | ||
156 | return 0; | |
157 | } | |
158 | core_initcall(cma_init_reserved_areas); | |
159 | ||
160 | /** | |
161 | * cma_init_reserved_mem() - create custom contiguous area from reserved memory | |
162 | * @base: Base address of the reserved area | |
163 | * @size: Size of the reserved area (in bytes), | |
164 | * @order_per_bit: Order of pages represented by one bit on bitmap. | |
165 | * @res_cma: Pointer to store the created cma region. | |
166 | * | |
167 | * This function creates custom contiguous area from already reserved memory. | |
168 | */ | |
169 | int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, | |
170 | unsigned int order_per_bit, | |
171 | struct cma **res_cma) | |
172 | { | |
173 | struct cma *cma; | |
174 | phys_addr_t alignment; | |
175 | ||
176 | /* Sanity checks */ | |
177 | if (cma_area_count == ARRAY_SIZE(cma_areas)) { | |
178 | pr_err("Not enough slots for CMA reserved regions!\n"); | |
179 | return -ENOSPC; | |
180 | } | |
181 | ||
182 | if (!size || !memblock_is_region_reserved(base, size)) | |
183 | return -EINVAL; | |
184 | ||
185 | /* ensure minimal alignment required by mm core */ | |
186 | alignment = PAGE_SIZE << | |
187 | max_t(unsigned long, MAX_ORDER - 1, pageblock_order); | |
188 | ||
189 | /* alignment should be aligned with order_per_bit */ | |
190 | if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit)) | |
191 | return -EINVAL; | |
192 | ||
193 | if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size) | |
194 | return -EINVAL; | |
195 | ||
196 | /* | |
197 | * Each reserved area must be initialised later, when more kernel | |
198 | * subsystems (like slab allocator) are available. | |
199 | */ | |
200 | cma = &cma_areas[cma_area_count]; | |
201 | cma->base_pfn = PFN_DOWN(base); | |
202 | cma->count = size >> PAGE_SHIFT; | |
203 | cma->order_per_bit = order_per_bit; | |
204 | *res_cma = cma; | |
205 | cma_area_count++; | |
206 | totalcma_pages += (size / PAGE_SIZE); | |
207 | ||
208 | return 0; | |
209 | } | |
210 | ||
211 | /** | |
212 | * cma_declare_contiguous() - reserve custom contiguous area | |
213 | * @base: Base address of the reserved area optional, use 0 for any | |
214 | * @size: Size of the reserved area (in bytes), | |
215 | * @limit: End address of the reserved memory (optional, 0 for any). | |
216 | * @alignment: Alignment for the CMA area, should be power of 2 or zero | |
217 | * @order_per_bit: Order of pages represented by one bit on bitmap. | |
218 | * @fixed: hint about where to place the reserved area | |
219 | * @res_cma: Pointer to store the created cma region. | |
220 | * | |
221 | * This function reserves memory from early allocator. It should be | |
222 | * called by arch specific code once the early allocator (memblock or bootmem) | |
223 | * has been activated and all other subsystems have already allocated/reserved | |
224 | * memory. This function allows to create custom reserved areas. | |
225 | * | |
226 | * If @fixed is true, reserve contiguous area at exactly @base. If false, | |
227 | * reserve in range from @base to @limit. | |
228 | */ | |
229 | int __init cma_declare_contiguous(phys_addr_t base, | |
230 | phys_addr_t size, phys_addr_t limit, | |
231 | phys_addr_t alignment, unsigned int order_per_bit, | |
232 | bool fixed, struct cma **res_cma) | |
233 | { | |
234 | phys_addr_t memblock_end = memblock_end_of_DRAM(); | |
235 | phys_addr_t highmem_start; | |
236 | int ret = 0; | |
237 | ||
238 | /* | |
239 | * We can't use __pa(high_memory) directly, since high_memory | |
240 | * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly) | |
241 | * complain. Find the boundary by adding one to the last valid | |
242 | * address. | |
243 | */ | |
244 | highmem_start = __pa(high_memory - 1) + 1; | |
245 | pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n", | |
246 | __func__, &size, &base, &limit, &alignment); | |
247 | ||
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, (phys_addr_t)PAGE_SIZE << | |
266 | max_t(unsigned long, MAX_ORDER - 1, pageblock_order)); | |
267 | base = ALIGN(base, alignment); | |
268 | size = ALIGN(size, alignment); | |
269 | limit &= ~(alignment - 1); | |
270 | ||
271 | if (!base) | |
272 | fixed = false; | |
273 | ||
274 | /* size should be aligned with order_per_bit */ | |
275 | if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit)) | |
276 | return -EINVAL; | |
277 | ||
278 | /* | |
279 | * If allocating at a fixed base the request region must not cross the | |
280 | * low/high memory boundary. | |
281 | */ | |
282 | if (fixed && base < highmem_start && base + size > highmem_start) { | |
283 | ret = -EINVAL; | |
284 | pr_err("Region at %pa defined on low/high memory boundary (%pa)\n", | |
285 | &base, &highmem_start); | |
286 | goto err; | |
287 | } | |
288 | ||
289 | /* | |
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 | ||
297 | /* Reserve memory */ | |
298 | if (fixed) { | |
299 | if (memblock_is_region_reserved(base, size) || | |
300 | memblock_reserve(base, size) < 0) { | |
301 | ret = -EBUSY; | |
302 | goto err; | |
303 | } | |
304 | } else { | |
305 | 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 | MEMBLOCK_NONE); | |
317 | limit = highmem_start; | |
318 | } | |
319 | ||
320 | if (!addr) { | |
321 | addr = memblock_alloc_range(size, alignment, base, | |
322 | limit, | |
323 | MEMBLOCK_NONE); | |
324 | if (!addr) { | |
325 | ret = -ENOMEM; | |
326 | goto err; | |
327 | } | |
328 | } | |
329 | ||
330 | /* | |
331 | * kmemleak scans/reads tracked objects for pointers to other | |
332 | * objects but this address isn't mapped and accessible | |
333 | */ | |
334 | kmemleak_ignore_phys(addr); | |
335 | base = addr; | |
336 | } | |
337 | ||
338 | ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma); | |
339 | if (ret) | |
340 | goto err; | |
341 | ||
342 | pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M, | |
343 | &base); | |
344 | return 0; | |
345 | ||
346 | err: | |
347 | pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M); | |
348 | return ret; | |
349 | } | |
350 | ||
351 | #ifdef CONFIG_CMA_DEBUG | |
352 | static void cma_debug_show_areas(struct cma *cma) | |
353 | { | |
354 | unsigned long next_zero_bit, next_set_bit; | |
355 | unsigned long start = 0; | |
356 | unsigned int nr_zero, nr_total = 0; | |
357 | ||
358 | mutex_lock(&cma->lock); | |
359 | pr_info("number of available pages: "); | |
360 | for (;;) { | |
361 | next_zero_bit = find_next_zero_bit(cma->bitmap, cma->count, start); | |
362 | if (next_zero_bit >= cma->count) | |
363 | break; | |
364 | next_set_bit = find_next_bit(cma->bitmap, cma->count, next_zero_bit); | |
365 | nr_zero = next_set_bit - next_zero_bit; | |
366 | pr_cont("%s%u@%lu", nr_total ? "+" : "", nr_zero, next_zero_bit); | |
367 | nr_total += nr_zero; | |
368 | start = next_zero_bit + nr_zero; | |
369 | } | |
370 | pr_cont("=> %u free of %lu total pages\n", nr_total, cma->count); | |
371 | mutex_unlock(&cma->lock); | |
372 | } | |
373 | #else | |
374 | static inline void cma_debug_show_areas(struct cma *cma) { } | |
375 | #endif | |
376 | ||
377 | /** | |
378 | * cma_alloc() - allocate pages from contiguous area | |
379 | * @cma: Contiguous memory region for which the allocation is performed. | |
380 | * @count: Requested number of pages. | |
381 | * @align: Requested alignment of pages (in PAGE_SIZE order). | |
382 | * | |
383 | * This function allocates part of contiguous memory on specific | |
384 | * contiguous memory area. | |
385 | */ | |
386 | struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, | |
387 | gfp_t gfp_mask) | |
388 | { | |
389 | unsigned long mask, offset; | |
390 | unsigned long pfn = -1; | |
391 | unsigned long start = 0; | |
392 | unsigned long bitmap_maxno, bitmap_no, bitmap_count; | |
393 | struct page *page = NULL; | |
394 | int ret = -ENOMEM; | |
395 | ||
396 | if (!cma || !cma->count) | |
397 | return NULL; | |
398 | ||
399 | pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma, | |
400 | count, align); | |
401 | ||
402 | if (!count) | |
403 | return NULL; | |
404 | ||
405 | mask = cma_bitmap_aligned_mask(cma, align); | |
406 | offset = cma_bitmap_aligned_offset(cma, align); | |
407 | bitmap_maxno = cma_bitmap_maxno(cma); | |
408 | bitmap_count = cma_bitmap_pages_to_bits(cma, count); | |
409 | ||
410 | if (bitmap_count > bitmap_maxno) | |
411 | return NULL; | |
412 | ||
413 | for (;;) { | |
414 | mutex_lock(&cma->lock); | |
415 | bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, | |
416 | bitmap_maxno, start, bitmap_count, mask, | |
417 | offset); | |
418 | if (bitmap_no >= bitmap_maxno) { | |
419 | mutex_unlock(&cma->lock); | |
420 | break; | |
421 | } | |
422 | bitmap_set(cma->bitmap, bitmap_no, bitmap_count); | |
423 | /* | |
424 | * It's safe to drop the lock here. We've marked this region for | |
425 | * our exclusive use. If the migration fails we will take the | |
426 | * lock again and unmark it. | |
427 | */ | |
428 | mutex_unlock(&cma->lock); | |
429 | ||
430 | pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); | |
431 | mutex_lock(&cma_mutex); | |
432 | ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, | |
433 | gfp_mask); | |
434 | mutex_unlock(&cma_mutex); | |
435 | if (ret == 0) { | |
436 | page = pfn_to_page(pfn); | |
437 | break; | |
438 | } | |
439 | ||
440 | cma_clear_bitmap(cma, pfn, count); | |
441 | if (ret != -EBUSY) | |
442 | break; | |
443 | ||
444 | pr_debug("%s(): memory range at %p is busy, retrying\n", | |
445 | __func__, pfn_to_page(pfn)); | |
446 | /* try again with a bit different memory target */ | |
447 | start = bitmap_no + mask + 1; | |
448 | } | |
449 | ||
450 | trace_cma_alloc(pfn, page, count, align); | |
451 | ||
452 | if (ret) { | |
453 | pr_info("%s: alloc failed, req-size: %zu pages, ret: %d\n", | |
454 | __func__, count, ret); | |
455 | cma_debug_show_areas(cma); | |
456 | } | |
457 | ||
458 | pr_debug("%s(): returned %p\n", __func__, page); | |
459 | return page; | |
460 | } | |
461 | ||
462 | /** | |
463 | * cma_release() - release allocated pages | |
464 | * @cma: Contiguous memory region for which the allocation is performed. | |
465 | * @pages: Allocated pages. | |
466 | * @count: Number of allocated pages. | |
467 | * | |
468 | * This function releases memory allocated by alloc_cma(). | |
469 | * It returns false when provided pages do not belong to contiguous area and | |
470 | * true otherwise. | |
471 | */ | |
472 | bool cma_release(struct cma *cma, const struct page *pages, unsigned int count) | |
473 | { | |
474 | unsigned long pfn; | |
475 | ||
476 | if (!cma || !pages) | |
477 | return false; | |
478 | ||
479 | pr_debug("%s(page %p)\n", __func__, (void *)pages); | |
480 | ||
481 | pfn = page_to_pfn(pages); | |
482 | ||
483 | if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) | |
484 | return false; | |
485 | ||
486 | VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); | |
487 | ||
488 | free_contig_range(pfn, count); | |
489 | cma_clear_bitmap(cma, pfn, count); | |
490 | trace_cma_release(pfn, pages, count); | |
491 | ||
492 | return true; | |
493 | } |