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 cma->count = 0;
105 return -ENOMEM;
106 }
107
108 WARN_ON_ONCE(!pfn_valid(pfn));
109 zone = page_zone(pfn_to_page(pfn));
110
111 do {
112 unsigned j;
113
114 base_pfn = pfn;
115 for (j = pageblock_nr_pages; j; --j, pfn++) {
116 WARN_ON_ONCE(!pfn_valid(pfn));
117 /*
118 * alloc_contig_range requires the pfn range
119 * specified to be in the same zone. Make this
120 * simple by forcing the entire CMA resv range
121 * to be in the same zone.
122 */
123 if (page_zone(pfn_to_page(pfn)) != zone)
124 goto err;
125 }
126 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
127 } while (--i);
128
129 mutex_init(&cma->lock);
130
131 #ifdef CONFIG_CMA_DEBUGFS
132 INIT_HLIST_HEAD(&cma->mem_head);
133 spin_lock_init(&cma->mem_head_lock);
134 #endif
135
136 return 0;
137
138 err:
139 kfree(cma->bitmap);
140 cma->count = 0;
141 return -EINVAL;
142 }
143
cma_init_reserved_areas(void)144 static int __init cma_init_reserved_areas(void)
145 {
146 int i;
147
148 for (i = 0; i < cma_area_count; i++) {
149 int ret = cma_activate_area(&cma_areas[i]);
150
151 if (ret)
152 return ret;
153 }
154
155 return 0;
156 }
157 core_initcall(cma_init_reserved_areas);
158
159 /**
160 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
161 * @base: Base address of the reserved area
162 * @size: Size of the reserved area (in bytes),
163 * @order_per_bit: Order of pages represented by one bit on bitmap.
164 * @res_cma: Pointer to store the created cma region.
165 *
166 * This function creates custom contiguous area from already reserved memory.
167 */
cma_init_reserved_mem(phys_addr_t base,phys_addr_t size,unsigned int order_per_bit,struct cma ** res_cma)168 int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
169 unsigned int order_per_bit,
170 struct cma **res_cma)
171 {
172 struct cma *cma;
173 phys_addr_t alignment;
174
175 /* Sanity checks */
176 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
177 pr_err("Not enough slots for CMA reserved regions!\n");
178 return -ENOSPC;
179 }
180
181 if (!size || !memblock_is_region_reserved(base, size))
182 return -EINVAL;
183
184 /* ensure minimal alignment required by mm core */
185 alignment = PAGE_SIZE <<
186 max_t(unsigned long, MAX_ORDER - 1, pageblock_order);
187
188 /* alignment should be aligned with order_per_bit */
189 if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
190 return -EINVAL;
191
192 if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
193 return -EINVAL;
194
195 /*
196 * Each reserved area must be initialised later, when more kernel
197 * subsystems (like slab allocator) are available.
198 */
199 cma = &cma_areas[cma_area_count];
200 cma->base_pfn = PFN_DOWN(base);
201 cma->count = size >> PAGE_SHIFT;
202 cma->order_per_bit = order_per_bit;
203 *res_cma = cma;
204 cma_area_count++;
205 totalcma_pages += (size / PAGE_SIZE);
206
207 return 0;
208 }
209
210 /**
211 * cma_declare_contiguous() - reserve custom contiguous area
212 * @base: Base address of the reserved area optional, use 0 for any
213 * @size: Size of the reserved area (in bytes),
214 * @limit: End address of the reserved memory (optional, 0 for any).
215 * @alignment: Alignment for the CMA area, should be power of 2 or zero
216 * @order_per_bit: Order of pages represented by one bit on bitmap.
217 * @fixed: hint about where to place the reserved area
218 * @res_cma: Pointer to store the created cma region.
219 *
220 * This function reserves memory from early allocator. It should be
221 * called by arch specific code once the early allocator (memblock or bootmem)
222 * has been activated and all other subsystems have already allocated/reserved
223 * memory. This function allows to create custom reserved areas.
224 *
225 * If @fixed is true, reserve contiguous area at exactly @base. If false,
226 * reserve in range from @base to @limit.
227 */
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)228 int __init cma_declare_contiguous(phys_addr_t base,
229 phys_addr_t size, phys_addr_t limit,
230 phys_addr_t alignment, unsigned int order_per_bit,
231 bool fixed, struct cma **res_cma)
232 {
233 phys_addr_t memblock_end = memblock_end_of_DRAM();
234 phys_addr_t highmem_start;
235 int ret = 0;
236
237 #ifdef CONFIG_X86
238 /*
239 * high_memory isn't direct mapped memory so retrieving its physical
240 * address isn't appropriate. But it would be useful to check the
241 * physical address of the highmem boundary so it's justifiable to get
242 * the physical address from it. On x86 there is a validation check for
243 * this case, so the following workaround is needed to avoid it.
244 */
245 highmem_start = __pa_nodebug(high_memory);
246 #else
247 highmem_start = __pa(high_memory);
248 #endif
249 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
250 __func__, &size, &base, &limit, &alignment);
251
252 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
253 pr_err("Not enough slots for CMA reserved regions!\n");
254 return -ENOSPC;
255 }
256
257 if (!size)
258 return -EINVAL;
259
260 if (alignment && !is_power_of_2(alignment))
261 return -EINVAL;
262
263 /*
264 * Sanitise input arguments.
265 * Pages both ends in CMA area could be merged into adjacent unmovable
266 * migratetype page by page allocator's buddy algorithm. In the case,
267 * you couldn't get a contiguous memory, which is not what we want.
268 */
269 alignment = max(alignment, (phys_addr_t)PAGE_SIZE <<
270 max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
271 if (fixed && base & (alignment - 1)) {
272 ret = -EINVAL;
273 pr_err("Region at %pa must be aligned to %pa bytes\n",
274 &base, &alignment);
275 goto err;
276 }
277 base = ALIGN(base, alignment);
278 size = ALIGN(size, alignment);
279 limit &= ~(alignment - 1);
280
281 if (!base)
282 fixed = false;
283
284 /* size should be aligned with order_per_bit */
285 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
286 return -EINVAL;
287
288 /*
289 * If allocating at a fixed base the request region must not cross the
290 * low/high memory boundary.
291 */
292 if (fixed && base < highmem_start && base + size > highmem_start) {
293 ret = -EINVAL;
294 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
295 &base, &highmem_start);
296 goto err;
297 }
298
299 /*
300 * If the limit is unspecified or above the memblock end, its effective
301 * value will be the memblock end. Set it explicitly to simplify further
302 * checks.
303 */
304 if (limit == 0 || limit > memblock_end)
305 limit = memblock_end;
306
307 if (base + size > limit) {
308 ret = -EINVAL;
309 pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",
310 &size, &base, &limit);
311 goto err;
312 }
313
314 /* Reserve memory */
315 if (fixed) {
316 if (memblock_is_region_reserved(base, size) ||
317 memblock_reserve(base, size) < 0) {
318 ret = -EBUSY;
319 goto err;
320 }
321 } else {
322 phys_addr_t addr = 0;
323
324 /*
325 * All pages in the reserved area must come from the same zone.
326 * If the requested region crosses the low/high memory boundary,
327 * try allocating from high memory first and fall back to low
328 * memory in case of failure.
329 */
330 if (base < highmem_start && limit > highmem_start) {
331 addr = memblock_alloc_range(size, alignment,
332 highmem_start, limit,
333 MEMBLOCK_NONE);
334 limit = highmem_start;
335 }
336
337 if (!addr) {
338 addr = memblock_alloc_range(size, alignment, base,
339 limit,
340 MEMBLOCK_NONE);
341 if (!addr) {
342 ret = -ENOMEM;
343 goto err;
344 }
345 }
346
347 /*
348 * kmemleak scans/reads tracked objects for pointers to other
349 * objects but this address isn't mapped and accessible
350 */
351 kmemleak_ignore(phys_to_virt(addr));
352 base = addr;
353 }
354
355 ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
356 if (ret)
357 goto free_mem;
358
359 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
360 &base);
361 return 0;
362
363 free_mem:
364 memblock_free(base, size);
365 err:
366 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
367 return ret;
368 }
369
370 /**
371 * cma_alloc() - allocate pages from contiguous area
372 * @cma: Contiguous memory region for which the allocation is performed.
373 * @count: Requested number of pages.
374 * @align: Requested alignment of pages (in PAGE_SIZE order).
375 *
376 * This function allocates part of contiguous memory on specific
377 * contiguous memory area.
378 */
cma_alloc(struct cma * cma,size_t count,unsigned int align)379 struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
380 {
381 unsigned long mask, offset;
382 unsigned long pfn = -1;
383 unsigned long start = 0;
384 unsigned long bitmap_maxno, bitmap_no, bitmap_count;
385 struct page *page = NULL;
386 int ret;
387
388 if (!cma || !cma->count)
389 return NULL;
390
391 pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
392 count, align);
393
394 if (!count)
395 return NULL;
396
397 mask = cma_bitmap_aligned_mask(cma, align);
398 offset = cma_bitmap_aligned_offset(cma, align);
399 bitmap_maxno = cma_bitmap_maxno(cma);
400 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
401
402 for (;;) {
403 mutex_lock(&cma->lock);
404 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
405 bitmap_maxno, start, bitmap_count, mask,
406 offset);
407 if (bitmap_no >= bitmap_maxno) {
408 mutex_unlock(&cma->lock);
409 break;
410 }
411 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
412 /*
413 * It's safe to drop the lock here. We've marked this region for
414 * our exclusive use. If the migration fails we will take the
415 * lock again and unmark it.
416 */
417 mutex_unlock(&cma->lock);
418
419 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
420 mutex_lock(&cma_mutex);
421 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
422 mutex_unlock(&cma_mutex);
423 if (ret == 0) {
424 page = pfn_to_page(pfn);
425 break;
426 }
427
428 cma_clear_bitmap(cma, pfn, count);
429 if (ret != -EBUSY)
430 break;
431
432 pr_debug("%s(): memory range at %p is busy, retrying\n",
433 __func__, pfn_to_page(pfn));
434 /* try again with a bit different memory target */
435 start = bitmap_no + mask + 1;
436 }
437
438 trace_cma_alloc(pfn, page, count, align);
439
440 pr_debug("%s(): returned %p\n", __func__, page);
441 return page;
442 }
443
444 /**
445 * cma_release() - release allocated pages
446 * @cma: Contiguous memory region for which the allocation is performed.
447 * @pages: Allocated pages.
448 * @count: Number of allocated pages.
449 *
450 * This function releases memory allocated by alloc_cma().
451 * It returns false when provided pages do not belong to contiguous area and
452 * true otherwise.
453 */
cma_release(struct cma * cma,const struct page * pages,unsigned int count)454 bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
455 {
456 unsigned long pfn;
457
458 if (!cma || !pages)
459 return false;
460
461 pr_debug("%s(page %p)\n", __func__, (void *)pages);
462
463 pfn = page_to_pfn(pages);
464
465 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
466 return false;
467
468 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
469
470 free_contig_range(pfn, count);
471 cma_clear_bitmap(cma, pfn, count);
472 trace_cma_release(pfn, pages, count);
473
474 return true;
475 }
476