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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/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
 39struct cma cma_areas[MAX_CMA_AREAS];
 40unsigned cma_area_count;
 41static DEFINE_MUTEX(cma_mutex);
 42
 43phys_addr_t cma_get_base(const struct cma *cma)
 44{
 45	return PFN_PHYS(cma->base_pfn);
 46}
 47
 48unsigned long cma_get_size(const struct cma *cma)
 49{
 50	return cma->count << PAGE_SHIFT;
 51}
 52
 53const char *cma_get_name(const struct cma *cma)
 54{
 55	return cma->name;
 56}
 57
 58static 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 */
 70static 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
 77static 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
 83static 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
 96static 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
136not_in_zone:
137	bitmap_free(cma->bitmap);
138out_error:
139	cma->count = 0;
140	pr_err("CMA area %s could not be activated\n", cma->name);
141	return;
142}
143
144static 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}
153core_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 */
167int __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 */
236int __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
365free_mem:
366	memblock_free(base, size);
367err:
368	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
369	return ret;
370}
371
372#ifdef CONFIG_CMA_DEBUG
373static 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
398static 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 */
411struct 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 */
508bool 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
531int 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}