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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/sizes.h>
28#include <linux/slab.h>
29#include <linux/log2.h>
30#include <linux/cma.h>
31#include <linux/highmem.h>
32#include <linux/io.h>
33#include <linux/kmemleak.h>
34#include <trace/events/cma.h>
35
36#include "cma.h"
37
38struct cma cma_areas[MAX_CMA_AREAS];
39unsigned cma_area_count;
40
41phys_addr_t cma_get_base(const struct cma *cma)
42{
43 return PFN_PHYS(cma->base_pfn);
44}
45
46unsigned long cma_get_size(const struct cma *cma)
47{
48 return cma->count << PAGE_SHIFT;
49}
50
51const char *cma_get_name(const struct cma *cma)
52{
53 return cma->name;
54}
55
56static 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 */
68static 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
75static 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
81static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
82 unsigned long count)
83{
84 unsigned long bitmap_no, bitmap_count;
85 unsigned long flags;
86
87 bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
88 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
89
90 spin_lock_irqsave(&cma->lock, flags);
91 bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
92 spin_unlock_irqrestore(&cma->lock, flags);
93}
94
95static void __init cma_activate_area(struct cma *cma)
96{
97 unsigned long base_pfn = cma->base_pfn, pfn;
98 struct zone *zone;
99
100 cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL);
101 if (!cma->bitmap)
102 goto out_error;
103
104 /*
105 * alloc_contig_range() requires the pfn range specified to be in the
106 * same zone. Simplify by forcing the entire CMA resv range to be in the
107 * same zone.
108 */
109 WARN_ON_ONCE(!pfn_valid(base_pfn));
110 zone = page_zone(pfn_to_page(base_pfn));
111 for (pfn = base_pfn + 1; pfn < base_pfn + cma->count; pfn++) {
112 WARN_ON_ONCE(!pfn_valid(pfn));
113 if (page_zone(pfn_to_page(pfn)) != zone)
114 goto not_in_zone;
115 }
116
117 for (pfn = base_pfn; pfn < base_pfn + cma->count;
118 pfn += pageblock_nr_pages)
119 init_cma_reserved_pageblock(pfn_to_page(pfn));
120
121 spin_lock_init(&cma->lock);
122
123#ifdef CONFIG_CMA_DEBUGFS
124 INIT_HLIST_HEAD(&cma->mem_head);
125 spin_lock_init(&cma->mem_head_lock);
126#endif
127
128 return;
129
130not_in_zone:
131 bitmap_free(cma->bitmap);
132out_error:
133 /* Expose all pages to the buddy, they are useless for CMA. */
134 for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++)
135 free_reserved_page(pfn_to_page(pfn));
136 totalcma_pages -= cma->count;
137 cma->count = 0;
138 pr_err("CMA area %s could not be activated\n", cma->name);
139 return;
140}
141
142static int __init cma_init_reserved_areas(void)
143{
144 int i;
145
146 for (i = 0; i < cma_area_count; i++)
147 cma_activate_area(&cma_areas[i]);
148
149 return 0;
150}
151core_initcall(cma_init_reserved_areas);
152
153/**
154 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
155 * @base: Base address of the reserved area
156 * @size: Size of the reserved area (in bytes),
157 * @order_per_bit: Order of pages represented by one bit on bitmap.
158 * @name: The name of the area. If this parameter is NULL, the name of
159 * the area will be set to "cmaN", where N is a running counter of
160 * used areas.
161 * @res_cma: Pointer to store the created cma region.
162 *
163 * This function creates custom contiguous area from already reserved memory.
164 */
165int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
166 unsigned int order_per_bit,
167 const char *name,
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
199 if (name)
200 snprintf(cma->name, CMA_MAX_NAME, name);
201 else
202 snprintf(cma->name, CMA_MAX_NAME, "cma%d\n", cma_area_count);
203
204 cma->base_pfn = PFN_DOWN(base);
205 cma->count = size >> PAGE_SHIFT;
206 cma->order_per_bit = order_per_bit;
207 *res_cma = cma;
208 cma_area_count++;
209 totalcma_pages += (size / PAGE_SIZE);
210
211 return 0;
212}
213
214/**
215 * cma_declare_contiguous_nid() - reserve custom contiguous area
216 * @base: Base address of the reserved area optional, use 0 for any
217 * @size: Size of the reserved area (in bytes),
218 * @limit: End address of the reserved memory (optional, 0 for any).
219 * @alignment: Alignment for the CMA area, should be power of 2 or zero
220 * @order_per_bit: Order of pages represented by one bit on bitmap.
221 * @fixed: hint about where to place the reserved area
222 * @name: The name of the area. See function cma_init_reserved_mem()
223 * @res_cma: Pointer to store the created cma region.
224 * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
225 *
226 * This function reserves memory from early allocator. It should be
227 * called by arch specific code once the early allocator (memblock or bootmem)
228 * has been activated and all other subsystems have already allocated/reserved
229 * memory. This function allows to create custom reserved areas.
230 *
231 * If @fixed is true, reserve contiguous area at exactly @base. If false,
232 * reserve in range from @base to @limit.
233 */
234int __init cma_declare_contiguous_nid(phys_addr_t base,
235 phys_addr_t size, phys_addr_t limit,
236 phys_addr_t alignment, unsigned int order_per_bit,
237 bool fixed, const char *name, struct cma **res_cma,
238 int nid)
239{
240 phys_addr_t memblock_end = memblock_end_of_DRAM();
241 phys_addr_t highmem_start;
242 int ret = 0;
243
244 /*
245 * We can't use __pa(high_memory) directly, since high_memory
246 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
247 * complain. Find the boundary by adding one to the last valid
248 * address.
249 */
250 highmem_start = __pa(high_memory - 1) + 1;
251 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
252 __func__, &size, &base, &limit, &alignment);
253
254 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
255 pr_err("Not enough slots for CMA reserved regions!\n");
256 return -ENOSPC;
257 }
258
259 if (!size)
260 return -EINVAL;
261
262 if (alignment && !is_power_of_2(alignment))
263 return -EINVAL;
264
265 /*
266 * Sanitise input arguments.
267 * Pages both ends in CMA area could be merged into adjacent unmovable
268 * migratetype page by page allocator's buddy algorithm. In the case,
269 * you couldn't get a contiguous memory, which is not what we want.
270 */
271 alignment = max(alignment, (phys_addr_t)PAGE_SIZE <<
272 max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
273 if (fixed && base & (alignment - 1)) {
274 ret = -EINVAL;
275 pr_err("Region at %pa must be aligned to %pa bytes\n",
276 &base, &alignment);
277 goto err;
278 }
279 base = ALIGN(base, alignment);
280 size = ALIGN(size, alignment);
281 limit &= ~(alignment - 1);
282
283 if (!base)
284 fixed = false;
285
286 /* size should be aligned with order_per_bit */
287 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
288 return -EINVAL;
289
290 /*
291 * If allocating at a fixed base the request region must not cross the
292 * low/high memory boundary.
293 */
294 if (fixed && base < highmem_start && base + size > highmem_start) {
295 ret = -EINVAL;
296 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
297 &base, &highmem_start);
298 goto err;
299 }
300
301 /*
302 * If the limit is unspecified or above the memblock end, its effective
303 * value will be the memblock end. Set it explicitly to simplify further
304 * checks.
305 */
306 if (limit == 0 || limit > memblock_end)
307 limit = memblock_end;
308
309 if (base + size > limit) {
310 ret = -EINVAL;
311 pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",
312 &size, &base, &limit);
313 goto err;
314 }
315
316 /* Reserve memory */
317 if (fixed) {
318 if (memblock_is_region_reserved(base, size) ||
319 memblock_reserve(base, size) < 0) {
320 ret = -EBUSY;
321 goto err;
322 }
323 } else {
324 phys_addr_t addr = 0;
325
326 /*
327 * All pages in the reserved area must come from the same zone.
328 * If the requested region crosses the low/high memory boundary,
329 * try allocating from high memory first and fall back to low
330 * memory in case of failure.
331 */
332 if (base < highmem_start && limit > highmem_start) {
333 addr = memblock_alloc_range_nid(size, alignment,
334 highmem_start, limit, nid, true);
335 limit = highmem_start;
336 }
337
338 /*
339 * If there is enough memory, try a bottom-up allocation first.
340 * It will place the new cma area close to the start of the node
341 * and guarantee that the compaction is moving pages out of the
342 * cma area and not into it.
343 * Avoid using first 4GB to not interfere with constrained zones
344 * like DMA/DMA32.
345 */
346#ifdef CONFIG_PHYS_ADDR_T_64BIT
347 if (!memblock_bottom_up() && memblock_end >= SZ_4G + size) {
348 memblock_set_bottom_up(true);
349 addr = memblock_alloc_range_nid(size, alignment, SZ_4G,
350 limit, nid, true);
351 memblock_set_bottom_up(false);
352 }
353#endif
354
355 if (!addr) {
356 addr = memblock_alloc_range_nid(size, alignment, base,
357 limit, nid, true);
358 if (!addr) {
359 ret = -ENOMEM;
360 goto err;
361 }
362 }
363
364 /*
365 * kmemleak scans/reads tracked objects for pointers to other
366 * objects but this address isn't mapped and accessible
367 */
368 kmemleak_ignore_phys(addr);
369 base = addr;
370 }
371
372 ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
373 if (ret)
374 goto free_mem;
375
376 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
377 &base);
378 return 0;
379
380free_mem:
381 memblock_free(base, size);
382err:
383 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
384 return ret;
385}
386
387#ifdef CONFIG_CMA_DEBUG
388static void cma_debug_show_areas(struct cma *cma)
389{
390 unsigned long next_zero_bit, next_set_bit, nr_zero;
391 unsigned long start = 0;
392 unsigned long nr_part, nr_total = 0;
393 unsigned long nbits = cma_bitmap_maxno(cma);
394
395 spin_lock_irq(&cma->lock);
396 pr_info("number of available pages: ");
397 for (;;) {
398 next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start);
399 if (next_zero_bit >= nbits)
400 break;
401 next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit);
402 nr_zero = next_set_bit - next_zero_bit;
403 nr_part = nr_zero << cma->order_per_bit;
404 pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part,
405 next_zero_bit);
406 nr_total += nr_part;
407 start = next_zero_bit + nr_zero;
408 }
409 pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count);
410 spin_unlock_irq(&cma->lock);
411}
412#else
413static inline void cma_debug_show_areas(struct cma *cma) { }
414#endif
415
416/**
417 * cma_alloc() - allocate pages from contiguous area
418 * @cma: Contiguous memory region for which the allocation is performed.
419 * @count: Requested number of pages.
420 * @align: Requested alignment of pages (in PAGE_SIZE order).
421 * @no_warn: Avoid printing message about failed allocation
422 *
423 * This function allocates part of contiguous memory on specific
424 * contiguous memory area.
425 */
426struct page *cma_alloc(struct cma *cma, unsigned long count,
427 unsigned int align, bool no_warn)
428{
429 unsigned long mask, offset;
430 unsigned long pfn = -1;
431 unsigned long start = 0;
432 unsigned long bitmap_maxno, bitmap_no, bitmap_count;
433 unsigned long i;
434 struct page *page = NULL;
435 int ret = -ENOMEM;
436
437 if (!cma || !cma->count || !cma->bitmap)
438 goto out;
439
440 pr_debug("%s(cma %p, count %lu, align %d)\n", __func__, (void *)cma,
441 count, align);
442
443 if (!count)
444 goto out;
445
446 trace_cma_alloc_start(cma->name, count, align);
447
448 mask = cma_bitmap_aligned_mask(cma, align);
449 offset = cma_bitmap_aligned_offset(cma, align);
450 bitmap_maxno = cma_bitmap_maxno(cma);
451 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
452
453 if (bitmap_count > bitmap_maxno)
454 goto out;
455
456 for (;;) {
457 spin_lock_irq(&cma->lock);
458 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
459 bitmap_maxno, start, bitmap_count, mask,
460 offset);
461 if (bitmap_no >= bitmap_maxno) {
462 spin_unlock_irq(&cma->lock);
463 break;
464 }
465 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
466 /*
467 * It's safe to drop the lock here. We've marked this region for
468 * our exclusive use. If the migration fails we will take the
469 * lock again and unmark it.
470 */
471 spin_unlock_irq(&cma->lock);
472
473 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
474 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
475 GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
476
477 if (ret == 0) {
478 page = pfn_to_page(pfn);
479 break;
480 }
481
482 cma_clear_bitmap(cma, pfn, count);
483 if (ret != -EBUSY)
484 break;
485
486 pr_debug("%s(): memory range at %p is busy, retrying\n",
487 __func__, pfn_to_page(pfn));
488
489 trace_cma_alloc_busy_retry(cma->name, pfn, pfn_to_page(pfn),
490 count, align);
491 /* try again with a bit different memory target */
492 start = bitmap_no + mask + 1;
493 }
494
495 trace_cma_alloc_finish(cma->name, pfn, page, count, align);
496
497 /*
498 * CMA can allocate multiple page blocks, which results in different
499 * blocks being marked with different tags. Reset the tags to ignore
500 * those page blocks.
501 */
502 if (page) {
503 for (i = 0; i < count; i++)
504 page_kasan_tag_reset(page + i);
505 }
506
507 if (ret && !no_warn) {
508 pr_err_ratelimited("%s: %s: alloc failed, req-size: %lu pages, ret: %d\n",
509 __func__, cma->name, count, ret);
510 cma_debug_show_areas(cma);
511 }
512
513 pr_debug("%s(): returned %p\n", __func__, page);
514out:
515 if (page) {
516 count_vm_event(CMA_ALLOC_SUCCESS);
517 cma_sysfs_account_success_pages(cma, count);
518 } else {
519 count_vm_event(CMA_ALLOC_FAIL);
520 if (cma)
521 cma_sysfs_account_fail_pages(cma, count);
522 }
523
524 return page;
525}
526
527/**
528 * cma_release() - release allocated pages
529 * @cma: Contiguous memory region for which the allocation is performed.
530 * @pages: Allocated pages.
531 * @count: Number of allocated pages.
532 *
533 * This function releases memory allocated by cma_alloc().
534 * It returns false when provided pages do not belong to contiguous area and
535 * true otherwise.
536 */
537bool cma_release(struct cma *cma, const struct page *pages,
538 unsigned long count)
539{
540 unsigned long pfn;
541
542 if (!cma || !pages)
543 return false;
544
545 pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count);
546
547 pfn = page_to_pfn(pages);
548
549 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
550 return false;
551
552 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
553
554 free_contig_range(pfn, count);
555 cma_clear_bitmap(cma, pfn, count);
556 trace_cma_release(cma->name, pfn, pages, count);
557
558 return true;
559}
560
561int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)
562{
563 int i;
564
565 for (i = 0; i < cma_area_count; i++) {
566 int ret = it(&cma_areas[i], data);
567
568 if (ret)
569 return ret;
570 }
571
572 return 0;
573}
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
42struct cma cma_areas[MAX_CMA_AREAS];
43unsigned cma_area_count;
44static DEFINE_MUTEX(cma_mutex);
45
46phys_addr_t cma_get_base(const struct cma *cma)
47{
48 return PFN_PHYS(cma->base_pfn);
49}
50
51unsigned long cma_get_size(const struct cma *cma)
52{
53 return cma->count << PAGE_SHIFT;
54}
55
56static 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 */
68static 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
78static 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
84static 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
97static 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
139err:
140 kfree(cma->bitmap);
141 cma->count = 0;
142 return -EINVAL;
143}
144
145static 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}
158core_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 */
169int __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 */
229int __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#ifdef CONFIG_X86
239 /*
240 * high_memory isn't direct mapped memory so retrieving its physical
241 * address isn't appropriate. But it would be useful to check the
242 * physical address of the highmem boundary so it's justifiable to get
243 * the physical address from it. On x86 there is a validation check for
244 * this case, so the following workaround is needed to avoid it.
245 */
246 highmem_start = __pa_nodebug(high_memory);
247#else
248 highmem_start = __pa(high_memory);
249#endif
250 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
251 __func__, &size, &base, &limit, &alignment);
252
253 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
254 pr_err("Not enough slots for CMA reserved regions!\n");
255 return -ENOSPC;
256 }
257
258 if (!size)
259 return -EINVAL;
260
261 if (alignment && !is_power_of_2(alignment))
262 return -EINVAL;
263
264 /*
265 * Sanitise input arguments.
266 * Pages both ends in CMA area could be merged into adjacent unmovable
267 * migratetype page by page allocator's buddy algorithm. In the case,
268 * you couldn't get a contiguous memory, which is not what we want.
269 */
270 alignment = max(alignment, (phys_addr_t)PAGE_SIZE <<
271 max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
272 base = ALIGN(base, alignment);
273 size = ALIGN(size, alignment);
274 limit &= ~(alignment - 1);
275
276 if (!base)
277 fixed = false;
278
279 /* size should be aligned with order_per_bit */
280 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
281 return -EINVAL;
282
283 /*
284 * If allocating at a fixed base the request region must not cross the
285 * low/high memory boundary.
286 */
287 if (fixed && base < highmem_start && base + size > highmem_start) {
288 ret = -EINVAL;
289 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
290 &base, &highmem_start);
291 goto err;
292 }
293
294 /*
295 * If the limit is unspecified or above the memblock end, its effective
296 * value will be the memblock end. Set it explicitly to simplify further
297 * checks.
298 */
299 if (limit == 0 || limit > memblock_end)
300 limit = memblock_end;
301
302 /* Reserve memory */
303 if (fixed) {
304 if (memblock_is_region_reserved(base, size) ||
305 memblock_reserve(base, size) < 0) {
306 ret = -EBUSY;
307 goto err;
308 }
309 } else {
310 phys_addr_t addr = 0;
311
312 /*
313 * All pages in the reserved area must come from the same zone.
314 * If the requested region crosses the low/high memory boundary,
315 * try allocating from high memory first and fall back to low
316 * memory in case of failure.
317 */
318 if (base < highmem_start && limit > highmem_start) {
319 addr = memblock_alloc_range(size, alignment,
320 highmem_start, limit,
321 MEMBLOCK_NONE);
322 limit = highmem_start;
323 }
324
325 if (!addr) {
326 addr = memblock_alloc_range(size, alignment, base,
327 limit,
328 MEMBLOCK_NONE);
329 if (!addr) {
330 ret = -ENOMEM;
331 goto err;
332 }
333 }
334
335 /*
336 * kmemleak scans/reads tracked objects for pointers to other
337 * objects but this address isn't mapped and accessible
338 */
339 kmemleak_ignore_phys(addr);
340 base = addr;
341 }
342
343 ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
344 if (ret)
345 goto err;
346
347 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
348 &base);
349 return 0;
350
351err:
352 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
353 return ret;
354}
355
356/**
357 * cma_alloc() - allocate pages from contiguous area
358 * @cma: Contiguous memory region for which the allocation is performed.
359 * @count: Requested number of pages.
360 * @align: Requested alignment of pages (in PAGE_SIZE order).
361 *
362 * This function allocates part of contiguous memory on specific
363 * contiguous memory area.
364 */
365struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
366{
367 unsigned long mask, offset;
368 unsigned long pfn = -1;
369 unsigned long start = 0;
370 unsigned long bitmap_maxno, bitmap_no, bitmap_count;
371 struct page *page = NULL;
372 int ret;
373
374 if (!cma || !cma->count)
375 return NULL;
376
377 pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
378 count, align);
379
380 if (!count)
381 return NULL;
382
383 mask = cma_bitmap_aligned_mask(cma, align);
384 offset = cma_bitmap_aligned_offset(cma, align);
385 bitmap_maxno = cma_bitmap_maxno(cma);
386 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
387
388 if (bitmap_count > bitmap_maxno)
389 return NULL;
390
391 for (;;) {
392 mutex_lock(&cma->lock);
393 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
394 bitmap_maxno, start, bitmap_count, mask,
395 offset);
396 if (bitmap_no >= bitmap_maxno) {
397 mutex_unlock(&cma->lock);
398 break;
399 }
400 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
401 /*
402 * It's safe to drop the lock here. We've marked this region for
403 * our exclusive use. If the migration fails we will take the
404 * lock again and unmark it.
405 */
406 mutex_unlock(&cma->lock);
407
408 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
409 mutex_lock(&cma_mutex);
410 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
411 mutex_unlock(&cma_mutex);
412 if (ret == 0) {
413 page = pfn_to_page(pfn);
414 break;
415 }
416
417 cma_clear_bitmap(cma, pfn, count);
418 if (ret != -EBUSY)
419 break;
420
421 pr_debug("%s(): memory range at %p is busy, retrying\n",
422 __func__, pfn_to_page(pfn));
423 /* try again with a bit different memory target */
424 start = bitmap_no + mask + 1;
425 }
426
427 trace_cma_alloc(pfn, page, count, align);
428
429 pr_debug("%s(): returned %p\n", __func__, page);
430 return page;
431}
432
433/**
434 * cma_release() - release allocated pages
435 * @cma: Contiguous memory region for which the allocation is performed.
436 * @pages: Allocated pages.
437 * @count: Number of allocated pages.
438 *
439 * This function releases memory allocated by alloc_cma().
440 * It returns false when provided pages do not belong to contiguous area and
441 * true otherwise.
442 */
443bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
444{
445 unsigned long pfn;
446
447 if (!cma || !pages)
448 return false;
449
450 pr_debug("%s(page %p)\n", __func__, (void *)pages);
451
452 pfn = page_to_pfn(pages);
453
454 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
455 return false;
456
457 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
458
459 free_contig_range(pfn, count);
460 cma_clear_bitmap(cma, pfn, count);
461 trace_cma_release(pfn, pages, count);
462
463 return true;
464}