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a254129e JK |
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 | ||
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> | |
f7426b98 | 35 | #include <linux/highmem.h> |
620951e2 | 36 | #include <linux/io.h> |
a254129e | 37 | |
28b24c1f SL |
38 | #include "cma.h" |
39 | ||
40 | struct cma cma_areas[MAX_CMA_AREAS]; | |
41 | unsigned cma_area_count; | |
a254129e JK |
42 | static DEFINE_MUTEX(cma_mutex); |
43 | ||
44 | phys_addr_t cma_get_base(struct cma *cma) | |
45 | { | |
46 | return PFN_PHYS(cma->base_pfn); | |
47 | } | |
48 | ||
49 | unsigned long cma_get_size(struct cma *cma) | |
50 | { | |
51 | return cma->count << PAGE_SHIFT; | |
52 | } | |
53 | ||
54 | static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order) | |
55 | { | |
68faed63 WY |
56 | if (align_order <= cma->order_per_bit) |
57 | return 0; | |
58 | return (1UL << (align_order - cma->order_per_bit)) - 1; | |
a254129e JK |
59 | } |
60 | ||
850fc430 DP |
61 | /* |
62 | * Find a PFN aligned to the specified order and return an offset represented in | |
63 | * order_per_bits. | |
64 | */ | |
b5be83e3 GF |
65 | static unsigned long cma_bitmap_aligned_offset(struct cma *cma, int align_order) |
66 | { | |
b5be83e3 GF |
67 | if (align_order <= cma->order_per_bit) |
68 | return 0; | |
850fc430 DP |
69 | |
70 | return (ALIGN(cma->base_pfn, (1UL << align_order)) | |
71 | - cma->base_pfn) >> cma->order_per_bit; | |
b5be83e3 GF |
72 | } |
73 | ||
a254129e JK |
74 | static unsigned long cma_bitmap_pages_to_bits(struct cma *cma, |
75 | unsigned long pages) | |
76 | { | |
77 | return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit; | |
78 | } | |
79 | ||
80 | static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count) | |
81 | { | |
82 | unsigned long bitmap_no, bitmap_count; | |
83 | ||
84 | bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit; | |
85 | bitmap_count = cma_bitmap_pages_to_bits(cma, count); | |
86 | ||
87 | mutex_lock(&cma->lock); | |
88 | bitmap_clear(cma->bitmap, bitmap_no, bitmap_count); | |
89 | mutex_unlock(&cma->lock); | |
90 | } | |
91 | ||
92 | static int __init cma_activate_area(struct cma *cma) | |
93 | { | |
94 | int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long); | |
95 | unsigned long base_pfn = cma->base_pfn, pfn = base_pfn; | |
96 | unsigned i = cma->count >> pageblock_order; | |
97 | struct zone *zone; | |
98 | ||
99 | cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL); | |
100 | ||
101 | if (!cma->bitmap) | |
102 | return -ENOMEM; | |
103 | ||
104 | WARN_ON_ONCE(!pfn_valid(pfn)); | |
105 | zone = page_zone(pfn_to_page(pfn)); | |
106 | ||
107 | do { | |
108 | unsigned j; | |
109 | ||
110 | base_pfn = pfn; | |
111 | for (j = pageblock_nr_pages; j; --j, pfn++) { | |
112 | WARN_ON_ONCE(!pfn_valid(pfn)); | |
113 | /* | |
114 | * alloc_contig_range requires the pfn range | |
115 | * specified to be in the same zone. Make this | |
116 | * simple by forcing the entire CMA resv range | |
117 | * to be in the same zone. | |
118 | */ | |
119 | if (page_zone(pfn_to_page(pfn)) != zone) | |
120 | goto err; | |
121 | } | |
122 | init_cma_reserved_pageblock(pfn_to_page(base_pfn)); | |
123 | } while (--i); | |
124 | ||
125 | mutex_init(&cma->lock); | |
26b02a1f SL |
126 | |
127 | #ifdef CONFIG_CMA_DEBUGFS | |
128 | INIT_HLIST_HEAD(&cma->mem_head); | |
129 | spin_lock_init(&cma->mem_head_lock); | |
130 | #endif | |
131 | ||
a254129e JK |
132 | return 0; |
133 | ||
134 | err: | |
135 | kfree(cma->bitmap); | |
f022d8cb | 136 | cma->count = 0; |
a254129e JK |
137 | return -EINVAL; |
138 | } | |
139 | ||
140 | static int __init cma_init_reserved_areas(void) | |
141 | { | |
142 | int i; | |
143 | ||
144 | for (i = 0; i < cma_area_count; i++) { | |
145 | int ret = cma_activate_area(&cma_areas[i]); | |
146 | ||
147 | if (ret) | |
148 | return ret; | |
149 | } | |
150 | ||
151 | return 0; | |
152 | } | |
153 | core_initcall(cma_init_reserved_areas); | |
154 | ||
de9e14ee MS |
155 | /** |
156 | * cma_init_reserved_mem() - create custom contiguous area from reserved memory | |
157 | * @base: Base address of the reserved area | |
158 | * @size: Size of the reserved area (in bytes), | |
159 | * @order_per_bit: Order of pages represented by one bit on bitmap. | |
160 | * @res_cma: Pointer to store the created cma region. | |
161 | * | |
162 | * This function creates custom contiguous area from already reserved memory. | |
163 | */ | |
164 | int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, | |
165 | int order_per_bit, struct cma **res_cma) | |
166 | { | |
167 | struct cma *cma; | |
168 | phys_addr_t alignment; | |
169 | ||
170 | /* Sanity checks */ | |
171 | if (cma_area_count == ARRAY_SIZE(cma_areas)) { | |
172 | pr_err("Not enough slots for CMA reserved regions!\n"); | |
173 | return -ENOSPC; | |
174 | } | |
175 | ||
176 | if (!size || !memblock_is_region_reserved(base, size)) | |
177 | return -EINVAL; | |
178 | ||
179 | /* ensure minimal alignment requied by mm core */ | |
180 | alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order); | |
181 | ||
182 | /* alignment should be aligned with order_per_bit */ | |
183 | if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit)) | |
184 | return -EINVAL; | |
185 | ||
186 | if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size) | |
187 | return -EINVAL; | |
188 | ||
189 | /* | |
190 | * Each reserved area must be initialised later, when more kernel | |
191 | * subsystems (like slab allocator) are available. | |
192 | */ | |
193 | cma = &cma_areas[cma_area_count]; | |
194 | cma->base_pfn = PFN_DOWN(base); | |
195 | cma->count = size >> PAGE_SHIFT; | |
196 | cma->order_per_bit = order_per_bit; | |
197 | *res_cma = cma; | |
198 | cma_area_count++; | |
94737a85 | 199 | totalcma_pages += (size / PAGE_SIZE); |
de9e14ee MS |
200 | |
201 | return 0; | |
202 | } | |
203 | ||
a254129e JK |
204 | /** |
205 | * cma_declare_contiguous() - reserve custom contiguous area | |
a254129e | 206 | * @base: Base address of the reserved area optional, use 0 for any |
c1f733aa | 207 | * @size: Size of the reserved area (in bytes), |
a254129e JK |
208 | * @limit: End address of the reserved memory (optional, 0 for any). |
209 | * @alignment: Alignment for the CMA area, should be power of 2 or zero | |
210 | * @order_per_bit: Order of pages represented by one bit on bitmap. | |
a254129e | 211 | * @fixed: hint about where to place the reserved area |
c1f733aa | 212 | * @res_cma: Pointer to store the created cma region. |
a254129e JK |
213 | * |
214 | * This function reserves memory from early allocator. It should be | |
215 | * called by arch specific code once the early allocator (memblock or bootmem) | |
216 | * has been activated and all other subsystems have already allocated/reserved | |
217 | * memory. This function allows to create custom reserved areas. | |
218 | * | |
219 | * If @fixed is true, reserve contiguous area at exactly @base. If false, | |
220 | * reserve in range from @base to @limit. | |
221 | */ | |
c1f733aa JK |
222 | int __init cma_declare_contiguous(phys_addr_t base, |
223 | phys_addr_t size, phys_addr_t limit, | |
a254129e | 224 | phys_addr_t alignment, unsigned int order_per_bit, |
c1f733aa | 225 | bool fixed, struct cma **res_cma) |
a254129e | 226 | { |
f7426b98 | 227 | phys_addr_t memblock_end = memblock_end_of_DRAM(); |
6b101e2a | 228 | phys_addr_t highmem_start; |
a254129e JK |
229 | int ret = 0; |
230 | ||
6b101e2a JK |
231 | #ifdef CONFIG_X86 |
232 | /* | |
233 | * high_memory isn't direct mapped memory so retrieving its physical | |
234 | * address isn't appropriate. But it would be useful to check the | |
235 | * physical address of the highmem boundary so it's justfiable to get | |
236 | * the physical address from it. On x86 there is a validation check for | |
237 | * this case, so the following workaround is needed to avoid it. | |
238 | */ | |
239 | highmem_start = __pa_nodebug(high_memory); | |
240 | #else | |
241 | highmem_start = __pa(high_memory); | |
242 | #endif | |
56fa4f60 LP |
243 | pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n", |
244 | __func__, &size, &base, &limit, &alignment); | |
a254129e JK |
245 | |
246 | if (cma_area_count == ARRAY_SIZE(cma_areas)) { | |
247 | pr_err("Not enough slots for CMA reserved regions!\n"); | |
248 | return -ENOSPC; | |
249 | } | |
250 | ||
251 | if (!size) | |
252 | return -EINVAL; | |
253 | ||
254 | if (alignment && !is_power_of_2(alignment)) | |
255 | return -EINVAL; | |
256 | ||
257 | /* | |
258 | * Sanitise input arguments. | |
259 | * Pages both ends in CMA area could be merged into adjacent unmovable | |
260 | * migratetype page by page allocator's buddy algorithm. In the case, | |
261 | * you couldn't get a contiguous memory, which is not what we want. | |
262 | */ | |
263 | alignment = max(alignment, | |
264 | (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order)); | |
265 | base = ALIGN(base, alignment); | |
266 | size = ALIGN(size, alignment); | |
267 | limit &= ~(alignment - 1); | |
268 | ||
800a85d3 LP |
269 | if (!base) |
270 | fixed = false; | |
271 | ||
a254129e JK |
272 | /* size should be aligned with order_per_bit */ |
273 | if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit)) | |
274 | return -EINVAL; | |
275 | ||
f7426b98 | 276 | /* |
16195ddd LP |
277 | * If allocating at a fixed base the request region must not cross the |
278 | * low/high memory boundary. | |
f7426b98 | 279 | */ |
16195ddd | 280 | if (fixed && base < highmem_start && base + size > highmem_start) { |
f7426b98 | 281 | ret = -EINVAL; |
56fa4f60 LP |
282 | pr_err("Region at %pa defined on low/high memory boundary (%pa)\n", |
283 | &base, &highmem_start); | |
f7426b98 MS |
284 | goto err; |
285 | } | |
286 | ||
16195ddd LP |
287 | /* |
288 | * If the limit is unspecified or above the memblock end, its effective | |
289 | * value will be the memblock end. Set it explicitly to simplify further | |
290 | * checks. | |
291 | */ | |
292 | if (limit == 0 || limit > memblock_end) | |
293 | limit = memblock_end; | |
294 | ||
a254129e | 295 | /* Reserve memory */ |
800a85d3 | 296 | if (fixed) { |
a254129e JK |
297 | if (memblock_is_region_reserved(base, size) || |
298 | memblock_reserve(base, size) < 0) { | |
299 | ret = -EBUSY; | |
300 | goto err; | |
301 | } | |
302 | } else { | |
16195ddd LP |
303 | phys_addr_t addr = 0; |
304 | ||
305 | /* | |
306 | * All pages in the reserved area must come from the same zone. | |
307 | * If the requested region crosses the low/high memory boundary, | |
308 | * try allocating from high memory first and fall back to low | |
309 | * memory in case of failure. | |
310 | */ | |
311 | if (base < highmem_start && limit > highmem_start) { | |
312 | addr = memblock_alloc_range(size, alignment, | |
313 | highmem_start, limit); | |
314 | limit = highmem_start; | |
315 | } | |
316 | ||
a254129e | 317 | if (!addr) { |
16195ddd LP |
318 | addr = memblock_alloc_range(size, alignment, base, |
319 | limit); | |
320 | if (!addr) { | |
321 | ret = -ENOMEM; | |
322 | goto err; | |
323 | } | |
a254129e | 324 | } |
16195ddd | 325 | |
620951e2 TR |
326 | /* |
327 | * kmemleak scans/reads tracked objects for pointers to other | |
328 | * objects but this address isn't mapped and accessible | |
329 | */ | |
330 | kmemleak_ignore(phys_to_virt(addr)); | |
16195ddd | 331 | base = addr; |
a254129e JK |
332 | } |
333 | ||
de9e14ee MS |
334 | ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma); |
335 | if (ret) | |
336 | goto err; | |
a254129e | 337 | |
56fa4f60 LP |
338 | pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M, |
339 | &base); | |
a254129e JK |
340 | return 0; |
341 | ||
342 | err: | |
0de9d2eb | 343 | pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M); |
a254129e JK |
344 | return ret; |
345 | } | |
346 | ||
347 | /** | |
348 | * cma_alloc() - allocate pages from contiguous area | |
349 | * @cma: Contiguous memory region for which the allocation is performed. | |
350 | * @count: Requested number of pages. | |
351 | * @align: Requested alignment of pages (in PAGE_SIZE order). | |
352 | * | |
353 | * This function allocates part of contiguous memory on specific | |
354 | * contiguous memory area. | |
355 | */ | |
356 | struct page *cma_alloc(struct cma *cma, int count, unsigned int align) | |
357 | { | |
b5be83e3 | 358 | unsigned long mask, offset, pfn, start = 0; |
a254129e JK |
359 | unsigned long bitmap_maxno, bitmap_no, bitmap_count; |
360 | struct page *page = NULL; | |
361 | int ret; | |
362 | ||
363 | if (!cma || !cma->count) | |
364 | return NULL; | |
365 | ||
366 | pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma, | |
367 | count, align); | |
368 | ||
369 | if (!count) | |
370 | return NULL; | |
371 | ||
372 | mask = cma_bitmap_aligned_mask(cma, align); | |
b5be83e3 | 373 | offset = cma_bitmap_aligned_offset(cma, align); |
a254129e JK |
374 | bitmap_maxno = cma_bitmap_maxno(cma); |
375 | bitmap_count = cma_bitmap_pages_to_bits(cma, count); | |
376 | ||
377 | for (;;) { | |
378 | mutex_lock(&cma->lock); | |
b5be83e3 GF |
379 | bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, |
380 | bitmap_maxno, start, bitmap_count, mask, | |
381 | offset); | |
a254129e JK |
382 | if (bitmap_no >= bitmap_maxno) { |
383 | mutex_unlock(&cma->lock); | |
384 | break; | |
385 | } | |
386 | bitmap_set(cma->bitmap, bitmap_no, bitmap_count); | |
387 | /* | |
388 | * It's safe to drop the lock here. We've marked this region for | |
389 | * our exclusive use. If the migration fails we will take the | |
390 | * lock again and unmark it. | |
391 | */ | |
392 | mutex_unlock(&cma->lock); | |
393 | ||
394 | pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); | |
395 | mutex_lock(&cma_mutex); | |
396 | ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA); | |
397 | mutex_unlock(&cma_mutex); | |
398 | if (ret == 0) { | |
399 | page = pfn_to_page(pfn); | |
400 | break; | |
a254129e | 401 | } |
b7155e76 | 402 | |
a254129e | 403 | cma_clear_bitmap(cma, pfn, count); |
b7155e76 JK |
404 | if (ret != -EBUSY) |
405 | break; | |
406 | ||
a254129e JK |
407 | pr_debug("%s(): memory range at %p is busy, retrying\n", |
408 | __func__, pfn_to_page(pfn)); | |
409 | /* try again with a bit different memory target */ | |
410 | start = bitmap_no + mask + 1; | |
411 | } | |
412 | ||
413 | pr_debug("%s(): returned %p\n", __func__, page); | |
414 | return page; | |
415 | } | |
416 | ||
417 | /** | |
418 | * cma_release() - release allocated pages | |
419 | * @cma: Contiguous memory region for which the allocation is performed. | |
420 | * @pages: Allocated pages. | |
421 | * @count: Number of allocated pages. | |
422 | * | |
423 | * This function releases memory allocated by alloc_cma(). | |
424 | * It returns false when provided pages do not belong to contiguous area and | |
425 | * true otherwise. | |
426 | */ | |
427 | bool cma_release(struct cma *cma, struct page *pages, int count) | |
428 | { | |
429 | unsigned long pfn; | |
430 | ||
431 | if (!cma || !pages) | |
432 | return false; | |
433 | ||
434 | pr_debug("%s(page %p)\n", __func__, (void *)pages); | |
435 | ||
436 | pfn = page_to_pfn(pages); | |
437 | ||
438 | if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) | |
439 | return false; | |
440 | ||
441 | VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); | |
442 | ||
443 | free_contig_range(pfn, count); | |
444 | cma_clear_bitmap(cma, pfn, count); | |
445 | ||
446 | return true; | |
447 | } |