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v6.8
  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 "internal.h"
 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 long count)
 85{
 86	unsigned long bitmap_no, bitmap_count;
 87	unsigned long flags;
 88
 89	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
 90	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
 91
 92	spin_lock_irqsave(&cma->lock, flags);
 93	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
 94	spin_unlock_irqrestore(&cma->lock, flags);
 95}
 96
 97static void __init cma_activate_area(struct cma *cma)
 98{
 99	unsigned long base_pfn = cma->base_pfn, pfn;
 
 
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	/*
107	 * alloc_contig_range() requires the pfn range specified to be in the
108	 * same zone. Simplify by forcing the entire CMA resv range to be in the
109	 * same zone.
110	 */
111	WARN_ON_ONCE(!pfn_valid(base_pfn));
112	zone = page_zone(pfn_to_page(base_pfn));
113	for (pfn = base_pfn + 1; pfn < base_pfn + cma->count; pfn++) {
114		WARN_ON_ONCE(!pfn_valid(pfn));
115		if (page_zone(pfn_to_page(pfn)) != zone)
116			goto not_in_zone;
117	}
118
119	for (pfn = base_pfn; pfn < base_pfn + cma->count;
120	     pfn += pageblock_nr_pages)
121		init_cma_reserved_pageblock(pfn_to_page(pfn));
 
 
 
 
 
 
 
 
 
122
123	spin_lock_init(&cma->lock);
124
125#ifdef CONFIG_CMA_DEBUGFS
126	INIT_HLIST_HEAD(&cma->mem_head);
127	spin_lock_init(&cma->mem_head_lock);
128#endif
129
130	return;
131
132not_in_zone:
133	bitmap_free(cma->bitmap);
134out_error:
135	/* Expose all pages to the buddy, they are useless for CMA. */
136	if (!cma->reserve_pages_on_error) {
137		for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++)
138			free_reserved_page(pfn_to_page(pfn));
139	}
140	totalcma_pages -= cma->count;
141	cma->count = 0;
142	pr_err("CMA area %s could not be activated\n", cma->name);
143	return;
 
 
144}
145
146static int __init cma_init_reserved_areas(void)
147{
148	int i;
149
150	for (i = 0; i < cma_area_count; i++)
151		cma_activate_area(&cma_areas[i]);
 
 
 
 
152
153	return 0;
154}
155core_initcall(cma_init_reserved_areas);
156
157void __init cma_reserve_pages_on_error(struct cma *cma)
158{
159	cma->reserve_pages_on_error = true;
160}
161
162/**
163 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
164 * @base: Base address of the reserved area
165 * @size: Size of the reserved area (in bytes),
166 * @order_per_bit: Order of pages represented by one bit on bitmap.
167 * @name: The name of the area. If this parameter is NULL, the name of
168 *        the area will be set to "cmaN", where N is a running counter of
169 *        used areas.
170 * @res_cma: Pointer to store the created cma region.
171 *
172 * This function creates custom contiguous area from already reserved memory.
173 */
174int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
175				 unsigned int order_per_bit,
176				 const char *name,
177				 struct cma **res_cma)
178{
179	struct cma *cma;
 
180
181	/* Sanity checks */
182	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
183		pr_err("Not enough slots for CMA reserved regions!\n");
184		return -ENOSPC;
185	}
186
187	if (!size || !memblock_is_region_reserved(base, size))
188		return -EINVAL;
189
 
 
 
 
190	/* alignment should be aligned with order_per_bit */
191	if (!IS_ALIGNED(CMA_MIN_ALIGNMENT_PAGES, 1 << order_per_bit))
192		return -EINVAL;
193
194	/* ensure minimal alignment required by mm core */
195	if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))
196		return -EINVAL;
197
198	/*
199	 * Each reserved area must be initialised later, when more kernel
200	 * subsystems (like slab allocator) are available.
201	 */
202	cma = &cma_areas[cma_area_count];
203
204	if (name)
205		snprintf(cma->name, CMA_MAX_NAME, name);
206	else
207		snprintf(cma->name, CMA_MAX_NAME,  "cma%d\n", cma_area_count);
208
 
209	cma->base_pfn = PFN_DOWN(base);
210	cma->count = size >> PAGE_SHIFT;
211	cma->order_per_bit = order_per_bit;
212	*res_cma = cma;
213	cma_area_count++;
214	totalcma_pages += (size / PAGE_SIZE);
215
216	return 0;
217}
218
219/**
220 * cma_declare_contiguous_nid() - reserve custom contiguous area
221 * @base: Base address of the reserved area optional, use 0 for any
222 * @size: Size of the reserved area (in bytes),
223 * @limit: End address of the reserved memory (optional, 0 for any).
224 * @alignment: Alignment for the CMA area, should be power of 2 or zero
225 * @order_per_bit: Order of pages represented by one bit on bitmap.
226 * @fixed: hint about where to place the reserved area
227 * @name: The name of the area. See function cma_init_reserved_mem()
228 * @res_cma: Pointer to store the created cma region.
229 * @nid: nid of the free area to find, %NUMA_NO_NODE for any node
230 *
231 * This function reserves memory from early allocator. It should be
232 * called by arch specific code once the early allocator (memblock or bootmem)
233 * has been activated and all other subsystems have already allocated/reserved
234 * memory. This function allows to create custom reserved areas.
235 *
236 * If @fixed is true, reserve contiguous area at exactly @base.  If false,
237 * reserve in range from @base to @limit.
238 */
239int __init cma_declare_contiguous_nid(phys_addr_t base,
240			phys_addr_t size, phys_addr_t limit,
241			phys_addr_t alignment, unsigned int order_per_bit,
242			bool fixed, const char *name, struct cma **res_cma,
243			int nid)
244{
245	phys_addr_t memblock_end = memblock_end_of_DRAM();
246	phys_addr_t highmem_start;
247	int ret;
248
249	/*
250	 * We can't use __pa(high_memory) directly, since high_memory
251	 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
252	 * complain. Find the boundary by adding one to the last valid
253	 * address.
254	 */
255	highmem_start = __pa(high_memory - 1) + 1;
256	pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
257		__func__, &size, &base, &limit, &alignment);
258
259	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
260		pr_err("Not enough slots for CMA reserved regions!\n");
261		return -ENOSPC;
262	}
263
264	if (!size)
265		return -EINVAL;
266
267	if (alignment && !is_power_of_2(alignment))
268		return -EINVAL;
269
270	if (!IS_ENABLED(CONFIG_NUMA))
271		nid = NUMA_NO_NODE;
272
273	/* Sanitise input arguments. */
274	alignment = max_t(phys_addr_t, alignment, CMA_MIN_ALIGNMENT_BYTES);
 
 
 
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		 * If there is enough memory, try a bottom-up allocation first.
330		 * It will place the new cma area close to the start of the node
331		 * and guarantee that the compaction is moving pages out of the
332		 * cma area and not into it.
333		 * Avoid using first 4GB to not interfere with constrained zones
334		 * like DMA/DMA32.
335		 */
336#ifdef CONFIG_PHYS_ADDR_T_64BIT
337		if (!memblock_bottom_up() && memblock_end >= SZ_4G + size) {
338			memblock_set_bottom_up(true);
339			addr = memblock_alloc_range_nid(size, alignment, SZ_4G,
340							limit, nid, true);
341			memblock_set_bottom_up(false);
342		}
343#endif
344
345		/*
346		 * All pages in the reserved area must come from the same zone.
347		 * If the requested region crosses the low/high memory boundary,
348		 * try allocating from high memory first and fall back to low
349		 * memory in case of failure.
350		 */
351		if (!addr && base < highmem_start && limit > highmem_start) {
352			addr = memblock_alloc_range_nid(size, alignment,
353					highmem_start, limit, nid, true);
354			limit = highmem_start;
355		}
356
357		if (!addr) {
358			addr = memblock_alloc_range_nid(size, alignment, base,
359					limit, nid, true);
360			if (!addr) {
361				ret = -ENOMEM;
362				goto err;
363			}
364		}
365
366		/*
367		 * kmemleak scans/reads tracked objects for pointers to other
368		 * objects but this address isn't mapped and accessible
369		 */
370		kmemleak_ignore_phys(addr);
371		base = addr;
372	}
373
374	ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
375	if (ret)
376		goto free_mem;
377
378	pr_info("Reserved %ld MiB at %pa on node %d\n", (unsigned long)size / SZ_1M,
379		&base, nid);
380	return 0;
381
382free_mem:
383	memblock_phys_free(base, size);
384err:
385	pr_err("Failed to reserve %ld MiB on node %d\n", (unsigned long)size / SZ_1M,
386	       nid);
387	return ret;
388}
389
390#ifdef CONFIG_CMA_DEBUG
391static void cma_debug_show_areas(struct cma *cma)
392{
393	unsigned long next_zero_bit, next_set_bit, nr_zero;
394	unsigned long start = 0;
395	unsigned long nr_part, nr_total = 0;
396	unsigned long nbits = cma_bitmap_maxno(cma);
397
398	spin_lock_irq(&cma->lock);
399	pr_info("number of available pages: ");
400	for (;;) {
401		next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start);
402		if (next_zero_bit >= nbits)
403			break;
404		next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit);
405		nr_zero = next_set_bit - next_zero_bit;
406		nr_part = nr_zero << cma->order_per_bit;
407		pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part,
408			next_zero_bit);
409		nr_total += nr_part;
410		start = next_zero_bit + nr_zero;
411	}
412	pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count);
413	spin_unlock_irq(&cma->lock);
414}
415#else
416static inline void cma_debug_show_areas(struct cma *cma) { }
417#endif
418
419/**
420 * cma_alloc() - allocate pages from contiguous area
421 * @cma:   Contiguous memory region for which the allocation is performed.
422 * @count: Requested number of pages.
423 * @align: Requested alignment of pages (in PAGE_SIZE order).
424 * @no_warn: Avoid printing message about failed allocation
425 *
426 * This function allocates part of contiguous memory on specific
427 * contiguous memory area.
428 */
429struct page *cma_alloc(struct cma *cma, unsigned long count,
430		       unsigned int align, bool no_warn)
431{
432	unsigned long mask, offset;
433	unsigned long pfn = -1;
434	unsigned long start = 0;
435	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
436	unsigned long i;
437	struct page *page = NULL;
438	int ret = -ENOMEM;
439
440	if (!cma || !cma->count || !cma->bitmap)
441		goto out;
442
443	pr_debug("%s(cma %p, name: %s, count %lu, align %d)\n", __func__,
444		(void *)cma, cma->name, count, align);
445
446	if (!count)
447		goto out;
448
449	trace_cma_alloc_start(cma->name, count, align);
450
451	mask = cma_bitmap_aligned_mask(cma, align);
452	offset = cma_bitmap_aligned_offset(cma, align);
453	bitmap_maxno = cma_bitmap_maxno(cma);
454	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
455
456	if (bitmap_count > bitmap_maxno)
457		goto out;
458
459	for (;;) {
460		spin_lock_irq(&cma->lock);
461		bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
462				bitmap_maxno, start, bitmap_count, mask,
463				offset);
464		if (bitmap_no >= bitmap_maxno) {
465			spin_unlock_irq(&cma->lock);
466			break;
467		}
468		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
469		/*
470		 * It's safe to drop the lock here. We've marked this region for
471		 * our exclusive use. If the migration fails we will take the
472		 * lock again and unmark it.
473		 */
474		spin_unlock_irq(&cma->lock);
475
476		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
477		mutex_lock(&cma_mutex);
478		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
479				     GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
480		mutex_unlock(&cma_mutex);
481		if (ret == 0) {
482			page = pfn_to_page(pfn);
483			break;
484		}
485
486		cma_clear_bitmap(cma, pfn, count);
487		if (ret != -EBUSY)
488			break;
489
490		pr_debug("%s(): memory range at pfn 0x%lx %p is busy, retrying\n",
491			 __func__, pfn, pfn_to_page(pfn));
492
493		trace_cma_alloc_busy_retry(cma->name, pfn, pfn_to_page(pfn),
494					   count, align);
495		/* try again with a bit different memory target */
496		start = bitmap_no + mask + 1;
497	}
498
499	trace_cma_alloc_finish(cma->name, pfn, page, count, align, ret);
500
501	/*
502	 * CMA can allocate multiple page blocks, which results in different
503	 * blocks being marked with different tags. Reset the tags to ignore
504	 * those page blocks.
505	 */
506	if (page) {
507		for (i = 0; i < count; i++)
508			page_kasan_tag_reset(nth_page(page, i));
509	}
510
511	if (ret && !no_warn) {
512		pr_err_ratelimited("%s: %s: alloc failed, req-size: %lu pages, ret: %d\n",
513				   __func__, cma->name, count, ret);
514		cma_debug_show_areas(cma);
515	}
516
517	pr_debug("%s(): returned %p\n", __func__, page);
518out:
519	if (page) {
520		count_vm_event(CMA_ALLOC_SUCCESS);
521		cma_sysfs_account_success_pages(cma, count);
522	} else {
523		count_vm_event(CMA_ALLOC_FAIL);
524		if (cma)
525			cma_sysfs_account_fail_pages(cma, count);
526	}
527
528	return page;
529}
530
531bool cma_pages_valid(struct cma *cma, const struct page *pages,
532		     unsigned long count)
533{
534	unsigned long pfn;
535
536	if (!cma || !pages)
537		return false;
538
539	pfn = page_to_pfn(pages);
540
541	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) {
542		pr_debug("%s(page %p, count %lu)\n", __func__,
543						(void *)pages, count);
544		return false;
545	}
546
547	return true;
548}
549
550/**
551 * cma_release() - release allocated pages
552 * @cma:   Contiguous memory region for which the allocation is performed.
553 * @pages: Allocated pages.
554 * @count: Number of allocated pages.
555 *
556 * This function releases memory allocated by cma_alloc().
557 * It returns false when provided pages do not belong to contiguous area and
558 * true otherwise.
559 */
560bool cma_release(struct cma *cma, const struct page *pages,
561		 unsigned long count)
562{
563	unsigned long pfn;
564
565	if (!cma_pages_valid(cma, pages, count))
566		return false;
567
568	pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count);
569
570	pfn = page_to_pfn(pages);
571
 
 
 
572	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
573
574	free_contig_range(pfn, count);
575	cma_clear_bitmap(cma, pfn, count);
576	trace_cma_release(cma->name, pfn, pages, count);
577
578	return true;
579}
580
581int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)
582{
583	int i;
584
585	for (i = 0; i < cma_area_count; i++) {
586		int ret = it(&cma_areas[i], data);
587
588		if (ret)
589			return ret;
590	}
591
592	return 0;
593}
v5.4
  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 ? cma->name : "(undefined)";
 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 int __init cma_activate_area(struct cma *cma)
 97{
 98	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
 99	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
100	unsigned i = cma->count >> pageblock_order;
101	struct zone *zone;
102
103	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
 
 
104
105	if (!cma->bitmap) {
106		cma->count = 0;
107		return -ENOMEM;
108	}
109
110	WARN_ON_ONCE(!pfn_valid(pfn));
111	zone = page_zone(pfn_to_page(pfn));
112
113	do {
114		unsigned j;
115
116		base_pfn = pfn;
117		for (j = pageblock_nr_pages; j; --j, pfn++) {
118			WARN_ON_ONCE(!pfn_valid(pfn));
119			/*
120			 * alloc_contig_range requires the pfn range
121			 * specified to be in the same zone. Make this
122			 * simple by forcing the entire CMA resv range
123			 * to be in the same zone.
124			 */
125			if (page_zone(pfn_to_page(pfn)) != zone)
126				goto not_in_zone;
127		}
128		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
129	} while (--i);
130
131	mutex_init(&cma->lock);
132
133#ifdef CONFIG_CMA_DEBUGFS
134	INIT_HLIST_HEAD(&cma->mem_head);
135	spin_lock_init(&cma->mem_head_lock);
136#endif
137
138	return 0;
139
140not_in_zone:
 
 
 
 
 
 
 
 
 
141	pr_err("CMA area %s could not be activated\n", cma->name);
142	kfree(cma->bitmap);
143	cma->count = 0;
144	return -EINVAL;
145}
146
147static int __init cma_init_reserved_areas(void)
148{
149	int i;
150
151	for (i = 0; i < cma_area_count; i++) {
152		int ret = cma_activate_area(&cma_areas[i]);
153
154		if (ret)
155			return ret;
156	}
157
158	return 0;
159}
160core_initcall(cma_init_reserved_areas);
161
 
 
 
 
 
162/**
163 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
164 * @base: Base address of the reserved area
165 * @size: Size of the reserved area (in bytes),
166 * @order_per_bit: Order of pages represented by one bit on bitmap.
167 * @name: The name of the area. If this parameter is NULL, the name of
168 *        the area will be set to "cmaN", where N is a running counter of
169 *        used areas.
170 * @res_cma: Pointer to store the created cma region.
171 *
172 * This function creates custom contiguous area from already reserved memory.
173 */
174int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
175				 unsigned int order_per_bit,
176				 const char *name,
177				 struct cma **res_cma)
178{
179	struct cma *cma;
180	phys_addr_t alignment;
181
182	/* Sanity checks */
183	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
184		pr_err("Not enough slots for CMA reserved regions!\n");
185		return -ENOSPC;
186	}
187
188	if (!size || !memblock_is_region_reserved(base, size))
189		return -EINVAL;
190
191	/* ensure minimal alignment required by mm core */
192	alignment = PAGE_SIZE <<
193			max_t(unsigned long, MAX_ORDER - 1, pageblock_order);
194
195	/* alignment should be aligned with order_per_bit */
196	if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
197		return -EINVAL;
198
199	if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
 
200		return -EINVAL;
201
202	/*
203	 * Each reserved area must be initialised later, when more kernel
204	 * subsystems (like slab allocator) are available.
205	 */
206	cma = &cma_areas[cma_area_count];
207	if (name) {
208		cma->name = name;
209	} else {
210		cma->name = kasprintf(GFP_KERNEL, "cma%d\n", cma_area_count);
211		if (!cma->name)
212			return -ENOMEM;
213	}
214	cma->base_pfn = PFN_DOWN(base);
215	cma->count = size >> PAGE_SHIFT;
216	cma->order_per_bit = order_per_bit;
217	*res_cma = cma;
218	cma_area_count++;
219	totalcma_pages += (size / PAGE_SIZE);
220
221	return 0;
222}
223
224/**
225 * cma_declare_contiguous() - reserve custom contiguous area
226 * @base: Base address of the reserved area optional, use 0 for any
227 * @size: Size of the reserved area (in bytes),
228 * @limit: End address of the reserved memory (optional, 0 for any).
229 * @alignment: Alignment for the CMA area, should be power of 2 or zero
230 * @order_per_bit: Order of pages represented by one bit on bitmap.
231 * @fixed: hint about where to place the reserved area
232 * @name: The name of the area. See function cma_init_reserved_mem()
233 * @res_cma: Pointer to store the created cma region.
 
234 *
235 * This function reserves memory from early allocator. It should be
236 * called by arch specific code once the early allocator (memblock or bootmem)
237 * has been activated and all other subsystems have already allocated/reserved
238 * memory. This function allows to create custom reserved areas.
239 *
240 * If @fixed is true, reserve contiguous area at exactly @base.  If false,
241 * reserve in range from @base to @limit.
242 */
243int __init cma_declare_contiguous(phys_addr_t base,
244			phys_addr_t size, phys_addr_t limit,
245			phys_addr_t alignment, unsigned int order_per_bit,
246			bool fixed, const char *name, struct cma **res_cma)
 
247{
248	phys_addr_t memblock_end = memblock_end_of_DRAM();
249	phys_addr_t highmem_start;
250	int ret = 0;
251
252	/*
253	 * We can't use __pa(high_memory) directly, since high_memory
254	 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
255	 * complain. Find the boundary by adding one to the last valid
256	 * address.
257	 */
258	highmem_start = __pa(high_memory - 1) + 1;
259	pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
260		__func__, &size, &base, &limit, &alignment);
261
262	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
263		pr_err("Not enough slots for CMA reserved regions!\n");
264		return -ENOSPC;
265	}
266
267	if (!size)
268		return -EINVAL;
269
270	if (alignment && !is_power_of_2(alignment))
271		return -EINVAL;
272
273	/*
274	 * Sanitise input arguments.
275	 * Pages both ends in CMA area could be merged into adjacent unmovable
276	 * migratetype page by page allocator's buddy algorithm. In the case,
277	 * you couldn't get a contiguous memory, which is not what we want.
278	 */
279	alignment = max(alignment,  (phys_addr_t)PAGE_SIZE <<
280			  max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
281	if (fixed && base & (alignment - 1)) {
282		ret = -EINVAL;
283		pr_err("Region at %pa must be aligned to %pa bytes\n",
284			&base, &alignment);
285		goto err;
286	}
287	base = ALIGN(base, alignment);
288	size = ALIGN(size, alignment);
289	limit &= ~(alignment - 1);
290
291	if (!base)
292		fixed = false;
293
294	/* size should be aligned with order_per_bit */
295	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
296		return -EINVAL;
297
298	/*
299	 * If allocating at a fixed base the request region must not cross the
300	 * low/high memory boundary.
301	 */
302	if (fixed && base < highmem_start && base + size > highmem_start) {
303		ret = -EINVAL;
304		pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
305			&base, &highmem_start);
306		goto err;
307	}
308
309	/*
310	 * If the limit is unspecified or above the memblock end, its effective
311	 * value will be the memblock end. Set it explicitly to simplify further
312	 * checks.
313	 */
314	if (limit == 0 || limit > memblock_end)
315		limit = memblock_end;
316
317	if (base + size > limit) {
318		ret = -EINVAL;
319		pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",
320			&size, &base, &limit);
321		goto err;
322	}
323
324	/* Reserve memory */
325	if (fixed) {
326		if (memblock_is_region_reserved(base, size) ||
327		    memblock_reserve(base, size) < 0) {
328			ret = -EBUSY;
329			goto err;
330		}
331	} else {
332		phys_addr_t addr = 0;
333
334		/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
335		 * All pages in the reserved area must come from the same zone.
336		 * If the requested region crosses the low/high memory boundary,
337		 * try allocating from high memory first and fall back to low
338		 * memory in case of failure.
339		 */
340		if (base < highmem_start && limit > highmem_start) {
341			addr = memblock_phys_alloc_range(size, alignment,
342							 highmem_start, limit);
343			limit = highmem_start;
344		}
345
346		if (!addr) {
347			addr = memblock_phys_alloc_range(size, alignment, base,
348							 limit);
349			if (!addr) {
350				ret = -ENOMEM;
351				goto err;
352			}
353		}
354
355		/*
356		 * kmemleak scans/reads tracked objects for pointers to other
357		 * objects but this address isn't mapped and accessible
358		 */
359		kmemleak_ignore_phys(addr);
360		base = addr;
361	}
362
363	ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
364	if (ret)
365		goto free_mem;
366
367	pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
368		&base);
369	return 0;
370
371free_mem:
372	memblock_free(base, size);
373err:
374	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 
375	return ret;
376}
377
378#ifdef CONFIG_CMA_DEBUG
379static void cma_debug_show_areas(struct cma *cma)
380{
381	unsigned long next_zero_bit, next_set_bit, nr_zero;
382	unsigned long start = 0;
383	unsigned long nr_part, nr_total = 0;
384	unsigned long nbits = cma_bitmap_maxno(cma);
385
386	mutex_lock(&cma->lock);
387	pr_info("number of available pages: ");
388	for (;;) {
389		next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start);
390		if (next_zero_bit >= nbits)
391			break;
392		next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit);
393		nr_zero = next_set_bit - next_zero_bit;
394		nr_part = nr_zero << cma->order_per_bit;
395		pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part,
396			next_zero_bit);
397		nr_total += nr_part;
398		start = next_zero_bit + nr_zero;
399	}
400	pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count);
401	mutex_unlock(&cma->lock);
402}
403#else
404static inline void cma_debug_show_areas(struct cma *cma) { }
405#endif
406
407/**
408 * cma_alloc() - allocate pages from contiguous area
409 * @cma:   Contiguous memory region for which the allocation is performed.
410 * @count: Requested number of pages.
411 * @align: Requested alignment of pages (in PAGE_SIZE order).
412 * @no_warn: Avoid printing message about failed allocation
413 *
414 * This function allocates part of contiguous memory on specific
415 * contiguous memory area.
416 */
417struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
418		       bool no_warn)
419{
420	unsigned long mask, offset;
421	unsigned long pfn = -1;
422	unsigned long start = 0;
423	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
424	size_t i;
425	struct page *page = NULL;
426	int ret = -ENOMEM;
427
428	if (!cma || !cma->count)
429		return NULL;
430
431	pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
432		 count, align);
433
434	if (!count)
435		return NULL;
 
 
436
437	mask = cma_bitmap_aligned_mask(cma, align);
438	offset = cma_bitmap_aligned_offset(cma, align);
439	bitmap_maxno = cma_bitmap_maxno(cma);
440	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
441
442	if (bitmap_count > bitmap_maxno)
443		return NULL;
444
445	for (;;) {
446		mutex_lock(&cma->lock);
447		bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
448				bitmap_maxno, start, bitmap_count, mask,
449				offset);
450		if (bitmap_no >= bitmap_maxno) {
451			mutex_unlock(&cma->lock);
452			break;
453		}
454		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
455		/*
456		 * It's safe to drop the lock here. We've marked this region for
457		 * our exclusive use. If the migration fails we will take the
458		 * lock again and unmark it.
459		 */
460		mutex_unlock(&cma->lock);
461
462		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
463		mutex_lock(&cma_mutex);
464		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
465				     GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
466		mutex_unlock(&cma_mutex);
467		if (ret == 0) {
468			page = pfn_to_page(pfn);
469			break;
470		}
471
472		cma_clear_bitmap(cma, pfn, count);
473		if (ret != -EBUSY)
474			break;
475
476		pr_debug("%s(): memory range at %p is busy, retrying\n",
477			 __func__, pfn_to_page(pfn));
 
 
 
478		/* try again with a bit different memory target */
479		start = bitmap_no + mask + 1;
480	}
481
482	trace_cma_alloc(pfn, page, count, align);
483
484	/*
485	 * CMA can allocate multiple page blocks, which results in different
486	 * blocks being marked with different tags. Reset the tags to ignore
487	 * those page blocks.
488	 */
489	if (page) {
490		for (i = 0; i < count; i++)
491			page_kasan_tag_reset(page + i);
492	}
493
494	if (ret && !no_warn) {
495		pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n",
496			__func__, count, ret);
497		cma_debug_show_areas(cma);
498	}
499
500	pr_debug("%s(): returned %p\n", __func__, page);
 
 
 
 
 
 
 
 
 
 
501	return page;
502}
503
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
504/**
505 * cma_release() - release allocated pages
506 * @cma:   Contiguous memory region for which the allocation is performed.
507 * @pages: Allocated pages.
508 * @count: Number of allocated pages.
509 *
510 * This function releases memory allocated by cma_alloc().
511 * It returns false when provided pages do not belong to contiguous area and
512 * true otherwise.
513 */
514bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
 
515{
516	unsigned long pfn;
517
518	if (!cma || !pages)
519		return false;
520
521	pr_debug("%s(page %p)\n", __func__, (void *)pages);
522
523	pfn = page_to_pfn(pages);
524
525	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
526		return false;
527
528	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
529
530	free_contig_range(pfn, count);
531	cma_clear_bitmap(cma, pfn, count);
532	trace_cma_release(pfn, pages, count);
533
534	return true;
535}
536
537int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)
538{
539	int i;
540
541	for (i = 0; i < cma_area_count; i++) {
542		int ret = it(&cma_areas[i], data);
543
544		if (ret)
545			return ret;
546	}
547
548	return 0;
549}