Linux Audio

Check our new training course

Loading...
Note: File does not exist in v3.1.
  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}