1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Contiguous Memory Allocator
4 *
5 * Copyright (c) 2010-2011 by Samsung Electronics.
6 * Copyright IBM Corporation, 2013
7 * Copyright LG Electronics Inc., 2014
8 * Written by:
9 * Marek Szyprowski <m.szyprowski@samsung.com>
10 * Michal Nazarewicz <mina86@mina86.com>
11 * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
12 * Joonsoo Kim <iamjoonsoo.kim@lge.com>
13 */
14
15 #define pr_fmt(fmt) "cma: " fmt
16
17 #ifdef CONFIG_CMA_DEBUG
18 #ifndef DEBUG
19 # define DEBUG
20 #endif
21 #endif
22 #define CREATE_TRACE_POINTS
23
24 #include <linux/memblock.h>
25 #include <linux/err.h>
26 #include <linux/mm.h>
27 #include <linux/mutex.h>
28 #include <linux/sizes.h>
29 #include <linux/slab.h>
30 #include <linux/log2.h>
31 #include <linux/cma.h>
32 #include <linux/highmem.h>
33 #include <linux/io.h>
34 #include <linux/kmemleak.h>
35 #include <trace/events/cma.h>
36
37 #include "cma.h"
38
39 struct cma cma_areas[MAX_CMA_AREAS];
40 unsigned cma_area_count;
41 static DEFINE_MUTEX(cma_mutex);
42
cma_get_base(const struct cma * cma)43 phys_addr_t cma_get_base(const struct cma *cma)
44 {
45 return PFN_PHYS(cma->base_pfn);
46 }
47
cma_get_size(const struct cma * cma)48 unsigned long cma_get_size(const struct cma *cma)
49 {
50 return cma->count << PAGE_SHIFT;
51 }
52
cma_get_name(const struct cma * cma)53 const char *cma_get_name(const struct cma *cma)
54 {
55 return cma->name;
56 }
57
cma_bitmap_aligned_mask(const struct cma * cma,unsigned int align_order)58 static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
59 unsigned int align_order)
60 {
61 if (align_order <= cma->order_per_bit)
62 return 0;
63 return (1UL << (align_order - cma->order_per_bit)) - 1;
64 }
65
66 /*
67 * Find the offset of the base PFN from the specified align_order.
68 * The value returned is represented in order_per_bits.
69 */
cma_bitmap_aligned_offset(const struct cma * cma,unsigned int align_order)70 static unsigned long cma_bitmap_aligned_offset(const struct cma *cma,
71 unsigned int align_order)
72 {
73 return (cma->base_pfn & ((1UL << align_order) - 1))
74 >> cma->order_per_bit;
75 }
76
cma_bitmap_pages_to_bits(const struct cma * cma,unsigned long pages)77 static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma,
78 unsigned long pages)
79 {
80 return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
81 }
82
cma_clear_bitmap(struct cma * cma,unsigned long pfn,unsigned int count)83 static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
84 unsigned int count)
85 {
86 unsigned long bitmap_no, bitmap_count;
87
88 bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
89 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
90
91 mutex_lock(&cma->lock);
92 bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
93 mutex_unlock(&cma->lock);
94 }
95
cma_activate_area(struct cma * cma)96 static void __init cma_activate_area(struct cma *cma)
97 {
98 unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
99 unsigned i = cma->count >> pageblock_order;
100 struct zone *zone;
101
102 cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL);
103 if (!cma->bitmap)
104 goto out_error;
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 not_in_zone;
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;
135
136 not_in_zone:
137 bitmap_free(cma->bitmap);
138 out_error:
139 cma->count = 0;
140 pr_err("CMA area %s could not be activated\n", cma->name);
141 return;
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 cma_activate_area(&cma_areas[i]);
150
151 return 0;
152 }
153 core_initcall(cma_init_reserved_areas);
154
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 * @name: The name of the area. If this parameter is NULL, the name of
161 * the area will be set to "cmaN", where N is a running counter of
162 * used areas.
163 * @res_cma: Pointer to store the created cma region.
164 *
165 * This function creates custom contiguous area from already reserved memory.
166 */
cma_init_reserved_mem(phys_addr_t base,phys_addr_t size,unsigned int order_per_bit,const char * name,struct cma ** res_cma)167 int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
168 unsigned int order_per_bit,
169 const char *name,
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
201 if (name)
202 snprintf(cma->name, CMA_MAX_NAME, name);
203 else
204 snprintf(cma->name, CMA_MAX_NAME, "cma%d\n", cma_area_count);
205
206 cma->base_pfn = PFN_DOWN(base);
207 cma->count = size >> PAGE_SHIFT;
208 cma->order_per_bit = order_per_bit;
209 *res_cma = cma;
210 cma_area_count++;
211 totalcma_pages += (size / PAGE_SIZE);
212
213 return 0;
214 }
215
216 /**
217 * cma_declare_contiguous_nid() - reserve custom contiguous area
218 * @base: Base address of the reserved area optional, use 0 for any
219 * @size: Size of the reserved area (in bytes),
220 * @limit: End address of the reserved memory (optional, 0 for any).
221 * @alignment: Alignment for the CMA area, should be power of 2 or zero
222 * @order_per_bit: Order of pages represented by one bit on bitmap.
223 * @fixed: hint about where to place the reserved area
224 * @name: The name of the area. See function cma_init_reserved_mem()
225 * @res_cma: Pointer to store the created cma region.
226 * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
227 *
228 * This function reserves memory from early allocator. It should be
229 * called by arch specific code once the early allocator (memblock or bootmem)
230 * has been activated and all other subsystems have already allocated/reserved
231 * memory. This function allows to create custom reserved areas.
232 *
233 * If @fixed is true, reserve contiguous area at exactly @base. If false,
234 * reserve in range from @base to @limit.
235 */
cma_declare_contiguous_nid(phys_addr_t base,phys_addr_t size,phys_addr_t limit,phys_addr_t alignment,unsigned int order_per_bit,bool fixed,const char * name,struct cma ** res_cma,int nid)236 int __init cma_declare_contiguous_nid(phys_addr_t base,
237 phys_addr_t size, phys_addr_t limit,
238 phys_addr_t alignment, unsigned int order_per_bit,
239 bool fixed, const char *name, struct cma **res_cma,
240 int nid)
241 {
242 phys_addr_t memblock_end = memblock_end_of_DRAM();
243 phys_addr_t highmem_start;
244 int ret = 0;
245
246 /*
247 * We can't use __pa(high_memory) directly, since high_memory
248 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
249 * complain. Find the boundary by adding one to the last valid
250 * address.
251 */
252 highmem_start = __pa(high_memory - 1) + 1;
253 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
254 __func__, &size, &base, &limit, &alignment);
255
256 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
257 pr_err("Not enough slots for CMA reserved regions!\n");
258 return -ENOSPC;
259 }
260
261 if (!size)
262 return -EINVAL;
263
264 if (alignment && !is_power_of_2(alignment))
265 return -EINVAL;
266
267 /*
268 * Sanitise input arguments.
269 * Pages both ends in CMA area could be merged into adjacent unmovable
270 * migratetype page by page allocator's buddy algorithm. In the case,
271 * you couldn't get a contiguous memory, which is not what we want.
272 */
273 alignment = max(alignment, (phys_addr_t)PAGE_SIZE <<
274 max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
275 if (fixed && base & (alignment - 1)) {
276 ret = -EINVAL;
277 pr_err("Region at %pa must be aligned to %pa bytes\n",
278 &base, &alignment);
279 goto err;
280 }
281 base = ALIGN(base, alignment);
282 size = ALIGN(size, alignment);
283 limit &= ~(alignment - 1);
284
285 if (!base)
286 fixed = false;
287
288 /* size should be aligned with order_per_bit */
289 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
290 return -EINVAL;
291
292 /*
293 * If allocating at a fixed base the request region must not cross the
294 * low/high memory boundary.
295 */
296 if (fixed && base < highmem_start && base + size > highmem_start) {
297 ret = -EINVAL;
298 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
299 &base, &highmem_start);
300 goto err;
301 }
302
303 /*
304 * If the limit is unspecified or above the memblock end, its effective
305 * value will be the memblock end. Set it explicitly to simplify further
306 * checks.
307 */
308 if (limit == 0 || limit > memblock_end)
309 limit = memblock_end;
310
311 if (base + size > limit) {
312 ret = -EINVAL;
313 pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",
314 &size, &base, &limit);
315 goto err;
316 }
317
318 /* Reserve memory */
319 if (fixed) {
320 if (memblock_is_region_reserved(base, size) ||
321 memblock_reserve(base, size) < 0) {
322 ret = -EBUSY;
323 goto err;
324 }
325 } else {
326 phys_addr_t addr = 0;
327
328 /*
329 * All pages in the reserved area must come from the same zone.
330 * If the requested region crosses the low/high memory boundary,
331 * try allocating from high memory first and fall back to low
332 * memory in case of failure.
333 */
334 if (base < highmem_start && limit > highmem_start) {
335 addr = memblock_alloc_range_nid(size, alignment,
336 highmem_start, limit, nid, true);
337 limit = highmem_start;
338 }
339
340 if (!addr) {
341 addr = memblock_alloc_range_nid(size, alignment, base,
342 limit, nid, true);
343 if (!addr) {
344 ret = -ENOMEM;
345 goto err;
346 }
347 }
348
349 /*
350 * kmemleak scans/reads tracked objects for pointers to other
351 * objects but this address isn't mapped and accessible
352 */
353 kmemleak_ignore_phys(addr);
354 base = addr;
355 }
356
357 ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
358 if (ret)
359 goto free_mem;
360
361 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
362 &base);
363 return 0;
364
365 free_mem:
366 memblock_free(base, size);
367 err:
368 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
369 return ret;
370 }
371
372 #ifdef CONFIG_CMA_DEBUG
cma_debug_show_areas(struct cma * cma)373 static void cma_debug_show_areas(struct cma *cma)
374 {
375 unsigned long next_zero_bit, next_set_bit, nr_zero;
376 unsigned long start = 0;
377 unsigned long nr_part, nr_total = 0;
378 unsigned long nbits = cma_bitmap_maxno(cma);
379
380 mutex_lock(&cma->lock);
381 pr_info("number of available pages: ");
382 for (;;) {
383 next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start);
384 if (next_zero_bit >= nbits)
385 break;
386 next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit);
387 nr_zero = next_set_bit - next_zero_bit;
388 nr_part = nr_zero << cma->order_per_bit;
389 pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part,
390 next_zero_bit);
391 nr_total += nr_part;
392 start = next_zero_bit + nr_zero;
393 }
394 pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count);
395 mutex_unlock(&cma->lock);
396 }
397 #else
cma_debug_show_areas(struct cma * cma)398 static inline void cma_debug_show_areas(struct cma *cma) { }
399 #endif
400
401 /**
402 * cma_alloc() - allocate pages from contiguous area
403 * @cma: Contiguous memory region for which the allocation is performed.
404 * @count: Requested number of pages.
405 * @align: Requested alignment of pages (in PAGE_SIZE order).
406 * @no_warn: Avoid printing message about failed allocation
407 *
408 * This function allocates part of contiguous memory on specific
409 * contiguous memory area.
410 */
cma_alloc(struct cma * cma,size_t count,unsigned int align,bool no_warn)411 struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
412 bool no_warn)
413 {
414 unsigned long mask, offset;
415 unsigned long pfn = -1;
416 unsigned long start = 0;
417 unsigned long bitmap_maxno, bitmap_no, bitmap_count;
418 size_t i;
419 struct page *page = NULL;
420 int ret = -ENOMEM;
421
422 if (!cma || !cma->count || !cma->bitmap)
423 return NULL;
424
425 pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
426 count, align);
427
428 if (!count)
429 return NULL;
430
431 mask = cma_bitmap_aligned_mask(cma, align);
432 offset = cma_bitmap_aligned_offset(cma, align);
433 bitmap_maxno = cma_bitmap_maxno(cma);
434 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
435
436 if (bitmap_count > bitmap_maxno)
437 return NULL;
438
439 for (;;) {
440 mutex_lock(&cma->lock);
441 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
442 bitmap_maxno, start, bitmap_count, mask,
443 offset);
444 if (bitmap_no >= bitmap_maxno) {
445 mutex_unlock(&cma->lock);
446 break;
447 }
448 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
449 /*
450 * It's safe to drop the lock here. We've marked this region for
451 * our exclusive use. If the migration fails we will take the
452 * lock again and unmark it.
453 */
454 mutex_unlock(&cma->lock);
455
456 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
457 mutex_lock(&cma_mutex);
458 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
459 GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
460 mutex_unlock(&cma_mutex);
461 if (ret == 0) {
462 page = pfn_to_page(pfn);
463 break;
464 }
465
466 cma_clear_bitmap(cma, pfn, count);
467 if (ret != -EBUSY)
468 break;
469
470 pr_debug("%s(): memory range at %p is busy, retrying\n",
471 __func__, pfn_to_page(pfn));
472 /* try again with a bit different memory target */
473 start = bitmap_no + mask + 1;
474 }
475
476 trace_cma_alloc(pfn, page, count, align);
477
478 /*
479 * CMA can allocate multiple page blocks, which results in different
480 * blocks being marked with different tags. Reset the tags to ignore
481 * those page blocks.
482 */
483 if (page) {
484 for (i = 0; i < count; i++)
485 page_kasan_tag_reset(page + i);
486 }
487
488 if (ret && !no_warn) {
489 pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n",
490 __func__, count, ret);
491 cma_debug_show_areas(cma);
492 }
493
494 pr_debug("%s(): returned %p\n", __func__, page);
495 return page;
496 }
497
498 /**
499 * cma_release() - release allocated pages
500 * @cma: Contiguous memory region for which the allocation is performed.
501 * @pages: Allocated pages.
502 * @count: Number of allocated pages.
503 *
504 * This function releases memory allocated by cma_alloc().
505 * It returns false when provided pages do not belong to contiguous area and
506 * true otherwise.
507 */
cma_release(struct cma * cma,const struct page * pages,unsigned int count)508 bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
509 {
510 unsigned long pfn;
511
512 if (!cma || !pages)
513 return false;
514
515 pr_debug("%s(page %p)\n", __func__, (void *)pages);
516
517 pfn = page_to_pfn(pages);
518
519 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
520 return false;
521
522 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
523
524 free_contig_range(pfn, count);
525 cma_clear_bitmap(cma, pfn, count);
526 trace_cma_release(pfn, pages, count);
527
528 return true;
529 }
530
cma_for_each_area(int (* it)(struct cma * cma,void * data),void * data)531 int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)
532 {
533 int i;
534
535 for (i = 0; i < cma_area_count; i++) {
536 int ret = it(&cma_areas[i], data);
537
538 if (ret)
539 return ret;
540 }
541
542 return 0;
543 }
544
