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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;
40static DEFINE_MUTEX(cma_mutex);
41
42phys_addr_t cma_get_base(const struct cma *cma)
43{
44 return PFN_PHYS(cma->base_pfn);
45}
46
47unsigned long cma_get_size(const struct cma *cma)
48{
49 return cma->count << PAGE_SHIFT;
50}
51
52const char *cma_get_name(const struct cma *cma)
53{
54 return cma->name;
55}
56
57static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
58 unsigned int align_order)
59{
60 if (align_order <= cma->order_per_bit)
61 return 0;
62 return (1UL << (align_order - cma->order_per_bit)) - 1;
63}
64
65/*
66 * Find the offset of the base PFN from the specified align_order.
67 * The value returned is represented in order_per_bits.
68 */
69static unsigned long cma_bitmap_aligned_offset(const struct cma *cma,
70 unsigned int align_order)
71{
72 return (cma->base_pfn & ((1UL << align_order) - 1))
73 >> cma->order_per_bit;
74}
75
76static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma,
77 unsigned long pages)
78{
79 return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
80}
81
82static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
83 unsigned long count)
84{
85 unsigned long bitmap_no, bitmap_count;
86 unsigned long flags;
87
88 bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
89 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
90
91 spin_lock_irqsave(&cma->lock, flags);
92 bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
93 spin_unlock_irqrestore(&cma->lock, flags);
94}
95
96static void __init cma_activate_area(struct cma *cma)
97{
98 unsigned long base_pfn = cma->base_pfn, pfn;
99 struct zone *zone;
100
101 cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL);
102 if (!cma->bitmap)
103 goto out_error;
104
105 /*
106 * alloc_contig_range() requires the pfn range specified to be in the
107 * same zone. Simplify by forcing the entire CMA resv range to be in the
108 * same zone.
109 */
110 WARN_ON_ONCE(!pfn_valid(base_pfn));
111 zone = page_zone(pfn_to_page(base_pfn));
112 for (pfn = base_pfn + 1; pfn < base_pfn + cma->count; pfn++) {
113 WARN_ON_ONCE(!pfn_valid(pfn));
114 if (page_zone(pfn_to_page(pfn)) != zone)
115 goto not_in_zone;
116 }
117
118 for (pfn = base_pfn; pfn < base_pfn + cma->count;
119 pfn += pageblock_nr_pages)
120 init_cma_reserved_pageblock(pfn_to_page(pfn));
121
122 spin_lock_init(&cma->lock);
123
124#ifdef CONFIG_CMA_DEBUGFS
125 INIT_HLIST_HEAD(&cma->mem_head);
126 spin_lock_init(&cma->mem_head_lock);
127#endif
128
129 return;
130
131not_in_zone:
132 bitmap_free(cma->bitmap);
133out_error:
134 /* Expose all pages to the buddy, they are useless for CMA. */
135 if (!cma->reserve_pages_on_error) {
136 for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++)
137 free_reserved_page(pfn_to_page(pfn));
138 }
139 totalcma_pages -= cma->count;
140 cma->count = 0;
141 pr_err("CMA area %s could not be activated\n", cma->name);
142 return;
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 cma_activate_area(&cma_areas[i]);
151
152 return 0;
153}
154core_initcall(cma_init_reserved_areas);
155
156void __init cma_reserve_pages_on_error(struct cma *cma)
157{
158 cma->reserve_pages_on_error = true;
159}
160
161/**
162 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
163 * @base: Base address of the reserved area
164 * @size: Size of the reserved area (in bytes),
165 * @order_per_bit: Order of pages represented by one bit on bitmap.
166 * @name: The name of the area. If this parameter is NULL, the name of
167 * the area will be set to "cmaN", where N is a running counter of
168 * used areas.
169 * @res_cma: Pointer to store the created cma region.
170 *
171 * This function creates custom contiguous area from already reserved memory.
172 */
173int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
174 unsigned int order_per_bit,
175 const char *name,
176 struct cma **res_cma)
177{
178 struct cma *cma;
179
180 /* Sanity checks */
181 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
182 pr_err("Not enough slots for CMA reserved regions!\n");
183 return -ENOSPC;
184 }
185
186 if (!size || !memblock_is_region_reserved(base, size))
187 return -EINVAL;
188
189 /* alignment should be aligned with order_per_bit */
190 if (!IS_ALIGNED(CMA_MIN_ALIGNMENT_PAGES, 1 << order_per_bit))
191 return -EINVAL;
192
193 /* ensure minimal alignment required by mm core */
194 if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))
195 return -EINVAL;
196
197 /*
198 * Each reserved area must be initialised later, when more kernel
199 * subsystems (like slab allocator) are available.
200 */
201 cma = &cma_areas[cma_area_count];
202
203 if (name)
204 snprintf(cma->name, CMA_MAX_NAME, name);
205 else
206 snprintf(cma->name, CMA_MAX_NAME, "cma%d\n", cma_area_count);
207
208 cma->base_pfn = PFN_DOWN(base);
209 cma->count = size >> PAGE_SHIFT;
210 cma->order_per_bit = order_per_bit;
211 *res_cma = cma;
212 cma_area_count++;
213 totalcma_pages += (size / PAGE_SIZE);
214
215 return 0;
216}
217
218/**
219 * cma_declare_contiguous_nid() - reserve custom contiguous area
220 * @base: Base address of the reserved area optional, use 0 for any
221 * @size: Size of the reserved area (in bytes),
222 * @limit: End address of the reserved memory (optional, 0 for any).
223 * @alignment: Alignment for the CMA area, should be power of 2 or zero
224 * @order_per_bit: Order of pages represented by one bit on bitmap.
225 * @fixed: hint about where to place the reserved area
226 * @name: The name of the area. See function cma_init_reserved_mem()
227 * @res_cma: Pointer to store the created cma region.
228 * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
229 *
230 * This function reserves memory from early allocator. It should be
231 * called by arch specific code once the early allocator (memblock or bootmem)
232 * has been activated and all other subsystems have already allocated/reserved
233 * memory. This function allows to create custom reserved areas.
234 *
235 * If @fixed is true, reserve contiguous area at exactly @base. If false,
236 * reserve in range from @base to @limit.
237 */
238int __init cma_declare_contiguous_nid(phys_addr_t base,
239 phys_addr_t size, phys_addr_t limit,
240 phys_addr_t alignment, unsigned int order_per_bit,
241 bool fixed, const char *name, struct cma **res_cma,
242 int nid)
243{
244 phys_addr_t memblock_end = memblock_end_of_DRAM();
245 phys_addr_t highmem_start;
246 int ret = 0;
247
248 /*
249 * We can't use __pa(high_memory) directly, since high_memory
250 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
251 * complain. Find the boundary by adding one to the last valid
252 * address.
253 */
254 highmem_start = __pa(high_memory - 1) + 1;
255 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
256 __func__, &size, &base, &limit, &alignment);
257
258 if (cma_area_count == ARRAY_SIZE(cma_areas)) {
259 pr_err("Not enough slots for CMA reserved regions!\n");
260 return -ENOSPC;
261 }
262
263 if (!size)
264 return -EINVAL;
265
266 if (alignment && !is_power_of_2(alignment))
267 return -EINVAL;
268
269 /* Sanitise input arguments. */
270 alignment = max_t(phys_addr_t, alignment, CMA_MIN_ALIGNMENT_BYTES);
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_nid(size, alignment,
332 highmem_start, limit, nid, true);
333 limit = highmem_start;
334 }
335
336 /*
337 * If there is enough memory, try a bottom-up allocation first.
338 * It will place the new cma area close to the start of the node
339 * and guarantee that the compaction is moving pages out of the
340 * cma area and not into it.
341 * Avoid using first 4GB to not interfere with constrained zones
342 * like DMA/DMA32.
343 */
344#ifdef CONFIG_PHYS_ADDR_T_64BIT
345 if (!memblock_bottom_up() && memblock_end >= SZ_4G + size) {
346 memblock_set_bottom_up(true);
347 addr = memblock_alloc_range_nid(size, alignment, SZ_4G,
348 limit, nid, true);
349 memblock_set_bottom_up(false);
350 }
351#endif
352
353 if (!addr) {
354 addr = memblock_alloc_range_nid(size, alignment, base,
355 limit, nid, true);
356 if (!addr) {
357 ret = -ENOMEM;
358 goto err;
359 }
360 }
361
362 /*
363 * kmemleak scans/reads tracked objects for pointers to other
364 * objects but this address isn't mapped and accessible
365 */
366 kmemleak_ignore_phys(addr);
367 base = addr;
368 }
369
370 ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
371 if (ret)
372 goto free_mem;
373
374 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
375 &base);
376 return 0;
377
378free_mem:
379 memblock_phys_free(base, size);
380err:
381 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
382 return ret;
383}
384
385#ifdef CONFIG_CMA_DEBUG
386static void cma_debug_show_areas(struct cma *cma)
387{
388 unsigned long next_zero_bit, next_set_bit, nr_zero;
389 unsigned long start = 0;
390 unsigned long nr_part, nr_total = 0;
391 unsigned long nbits = cma_bitmap_maxno(cma);
392
393 spin_lock_irq(&cma->lock);
394 pr_info("number of available pages: ");
395 for (;;) {
396 next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start);
397 if (next_zero_bit >= nbits)
398 break;
399 next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit);
400 nr_zero = next_set_bit - next_zero_bit;
401 nr_part = nr_zero << cma->order_per_bit;
402 pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part,
403 next_zero_bit);
404 nr_total += nr_part;
405 start = next_zero_bit + nr_zero;
406 }
407 pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count);
408 spin_unlock_irq(&cma->lock);
409}
410#else
411static inline void cma_debug_show_areas(struct cma *cma) { }
412#endif
413
414/**
415 * cma_alloc() - allocate pages from contiguous area
416 * @cma: Contiguous memory region for which the allocation is performed.
417 * @count: Requested number of pages.
418 * @align: Requested alignment of pages (in PAGE_SIZE order).
419 * @no_warn: Avoid printing message about failed allocation
420 *
421 * This function allocates part of contiguous memory on specific
422 * contiguous memory area.
423 */
424struct page *cma_alloc(struct cma *cma, unsigned long count,
425 unsigned int align, bool no_warn)
426{
427 unsigned long mask, offset;
428 unsigned long pfn = -1;
429 unsigned long start = 0;
430 unsigned long bitmap_maxno, bitmap_no, bitmap_count;
431 unsigned long i;
432 struct page *page = NULL;
433 int ret = -ENOMEM;
434
435 if (!cma || !cma->count || !cma->bitmap)
436 goto out;
437
438 pr_debug("%s(cma %p, count %lu, align %d)\n", __func__, (void *)cma,
439 count, align);
440
441 if (!count)
442 goto out;
443
444 trace_cma_alloc_start(cma->name, count, align);
445
446 mask = cma_bitmap_aligned_mask(cma, align);
447 offset = cma_bitmap_aligned_offset(cma, align);
448 bitmap_maxno = cma_bitmap_maxno(cma);
449 bitmap_count = cma_bitmap_pages_to_bits(cma, count);
450
451 if (bitmap_count > bitmap_maxno)
452 goto out;
453
454 for (;;) {
455 spin_lock_irq(&cma->lock);
456 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
457 bitmap_maxno, start, bitmap_count, mask,
458 offset);
459 if (bitmap_no >= bitmap_maxno) {
460 spin_unlock_irq(&cma->lock);
461 break;
462 }
463 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
464 /*
465 * It's safe to drop the lock here. We've marked this region for
466 * our exclusive use. If the migration fails we will take the
467 * lock again and unmark it.
468 */
469 spin_unlock_irq(&cma->lock);
470
471 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
472 mutex_lock(&cma_mutex);
473 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
474 GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
475 mutex_unlock(&cma_mutex);
476 if (ret == 0) {
477 page = pfn_to_page(pfn);
478 break;
479 }
480
481 cma_clear_bitmap(cma, pfn, count);
482 if (ret != -EBUSY)
483 break;
484
485 pr_debug("%s(): memory range at %p is busy, retrying\n",
486 __func__, pfn_to_page(pfn));
487
488 trace_cma_alloc_busy_retry(cma->name, pfn, pfn_to_page(pfn),
489 count, align);
490 /* try again with a bit different memory target */
491 start = bitmap_no + mask + 1;
492 }
493
494 trace_cma_alloc_finish(cma->name, pfn, page, count, align);
495
496 /*
497 * CMA can allocate multiple page blocks, which results in different
498 * blocks being marked with different tags. Reset the tags to ignore
499 * those page blocks.
500 */
501 if (page) {
502 for (i = 0; i < count; i++)
503 page_kasan_tag_reset(page + i);
504 }
505
506 if (ret && !no_warn) {
507 pr_err_ratelimited("%s: %s: alloc failed, req-size: %lu pages, ret: %d\n",
508 __func__, cma->name, count, ret);
509 cma_debug_show_areas(cma);
510 }
511
512 pr_debug("%s(): returned %p\n", __func__, page);
513out:
514 if (page) {
515 count_vm_event(CMA_ALLOC_SUCCESS);
516 cma_sysfs_account_success_pages(cma, count);
517 } else {
518 count_vm_event(CMA_ALLOC_FAIL);
519 if (cma)
520 cma_sysfs_account_fail_pages(cma, count);
521 }
522
523 return page;
524}
525
526bool cma_pages_valid(struct cma *cma, const struct page *pages,
527 unsigned long count)
528{
529 unsigned long pfn;
530
531 if (!cma || !pages)
532 return false;
533
534 pfn = page_to_pfn(pages);
535
536 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) {
537 pr_debug("%s(page %p, count %lu)\n", __func__,
538 (void *)pages, count);
539 return false;
540 }
541
542 return true;
543}
544
545/**
546 * cma_release() - release allocated pages
547 * @cma: Contiguous memory region for which the allocation is performed.
548 * @pages: Allocated pages.
549 * @count: Number of allocated pages.
550 *
551 * This function releases memory allocated by cma_alloc().
552 * It returns false when provided pages do not belong to contiguous area and
553 * true otherwise.
554 */
555bool cma_release(struct cma *cma, const struct page *pages,
556 unsigned long count)
557{
558 unsigned long pfn;
559
560 if (!cma_pages_valid(cma, pages, count))
561 return false;
562
563 pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count);
564
565 pfn = page_to_pfn(pages);
566
567 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
568
569 free_contig_range(pfn, count);
570 cma_clear_bitmap(cma, pfn, count);
571 trace_cma_release(cma->name, pfn, pages, count);
572
573 return true;
574}
575
576int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)
577{
578 int i;
579
580 for (i = 0; i < cma_area_count; i++) {
581 int ret = it(&cma_areas[i], data);
582
583 if (ret)
584 return ret;
585 }
586
587 return 0;
588}