[linux.git] / mm / cma.c

/*
 * Contiguous Memory Allocator
 *
 * Copyright (c) 2010-2011 by Samsung Electronics.
 * Copyright IBM Corporation, 2013
 * Copyright LG Electronics Inc., 2014
 * Written by:
 *	Marek Szyprowski <[email protected]>
 *	Michal Nazarewicz <[email protected]>
 *	Aneesh Kumar K.V <[email protected]>
 *	Joonsoo Kim <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License or (at your optional) any later version of the license.
 */

#define pr_fmt(fmt) "cma: " fmt

#ifdef CONFIG_CMA_DEBUG
#ifndef DEBUG
#  define DEBUG
#endif
#endif

#include <linux/memblock.h>
#include <linux/err.h>
#include <linux/mm.h>
#include <linux/mutex.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/log2.h>
#include <linux/cma.h>
#include <linux/highmem.h>

struct cma {
	unsigned long	base_pfn;
	unsigned long	count;
	unsigned long	*bitmap;
	unsigned int order_per_bit; /* Order of pages represented by one bit */
	struct mutex	lock;
};

static struct cma cma_areas[MAX_CMA_AREAS];
static unsigned cma_area_count;
static DEFINE_MUTEX(cma_mutex);

phys_addr_t cma_get_base(struct cma *cma)
{
	return PFN_PHYS(cma->base_pfn);
}

unsigned long cma_get_size(struct cma *cma)
{
	return cma->count << PAGE_SHIFT;
}

static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
{
	if (align_order <= cma->order_per_bit)
		return 0;
	return (1UL << (align_order - cma->order_per_bit)) - 1;
}

static unsigned long cma_bitmap_aligned_offset(struct cma *cma, int align_order)
{
	unsigned int alignment;

	if (align_order <= cma->order_per_bit)
		return 0;
	alignment = 1UL << (align_order - cma->order_per_bit);
	return ALIGN(cma->base_pfn, alignment) -
		(cma->base_pfn >> cma->order_per_bit);
}

static unsigned long cma_bitmap_maxno(struct cma *cma)
{
	return cma->count >> cma->order_per_bit;
}

static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
						unsigned long pages)
{
	return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
}

static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
{
	unsigned long bitmap_no, bitmap_count;

	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
	bitmap_count = cma_bitmap_pages_to_bits(cma, count);

	mutex_lock(&cma->lock);
	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
	mutex_unlock(&cma->lock);
}

static int __init cma_activate_area(struct cma *cma)
{
	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
	unsigned i = cma->count >> pageblock_order;
	struct zone *zone;

	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);

	if (!cma->bitmap)
		return -ENOMEM;

	WARN_ON_ONCE(!pfn_valid(pfn));
	zone = page_zone(pfn_to_page(pfn));

	do {
		unsigned j;

		base_pfn = pfn;
		for (j = pageblock_nr_pages; j; --j, pfn++) {
			WARN_ON_ONCE(!pfn_valid(pfn));
			/*
			 * alloc_contig_range requires the pfn range
			 * specified to be in the same zone. Make this
			 * simple by forcing the entire CMA resv range
			 * to be in the same zone.
			 */
			if (page_zone(pfn_to_page(pfn)) != zone)
				goto err;
		}
		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
	} while (--i);

	mutex_init(&cma->lock);
	return 0;

err:
	kfree(cma->bitmap);
	cma->count = 0;
	return -EINVAL;
}

static int __init cma_init_reserved_areas(void)
{
	int i;

	for (i = 0; i < cma_area_count; i++) {
		int ret = cma_activate_area(&cma_areas[i]);

		if (ret)
			return ret;
	}

	return 0;
}
core_initcall(cma_init_reserved_areas);

/**
 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
 * @base: Base address of the reserved area
 * @size: Size of the reserved area (in bytes),
 * @order_per_bit: Order of pages represented by one bit on bitmap.
 * @res_cma: Pointer to store the created cma region.
 *
 * This function creates custom contiguous area from already reserved memory.
 */
int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
				 int order_per_bit, struct cma **res_cma)
{
	struct cma *cma;
	phys_addr_t alignment;

	/* Sanity checks */
	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
		pr_err("Not enough slots for CMA reserved regions!\n");
		return -ENOSPC;
	}

	if (!size || !memblock_is_region_reserved(base, size))
		return -EINVAL;

	/* ensure minimal alignment requied by mm core */
	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);

	/* alignment should be aligned with order_per_bit */
	if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
		return -EINVAL;

	if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
		return -EINVAL;

	/*
	 * Each reserved area must be initialised later, when more kernel
	 * subsystems (like slab allocator) are available.
	 */
	cma = &cma_areas[cma_area_count];
	cma->base_pfn = PFN_DOWN(base);
	cma->count = size >> PAGE_SHIFT;
	cma->order_per_bit = order_per_bit;
	*res_cma = cma;
	cma_area_count++;

	return 0;
}

/**
 * cma_declare_contiguous() - reserve custom contiguous area
 * @base: Base address of the reserved area optional, use 0 for any
 * @size: Size of the reserved area (in bytes),
 * @limit: End address of the reserved memory (optional, 0 for any).
 * @alignment: Alignment for the CMA area, should be power of 2 or zero
 * @order_per_bit: Order of pages represented by one bit on bitmap.
 * @fixed: hint about where to place the reserved area
 * @res_cma: Pointer to store the created cma region.
 *
 * This function reserves memory from early allocator. It should be
 * called by arch specific code once the early allocator (memblock or bootmem)
 * has been activated and all other subsystems have already allocated/reserved
 * memory. This function allows to create custom reserved areas.
 *
 * If @fixed is true, reserve contiguous area at exactly @base.  If false,
 * reserve in range from @base to @limit.
 */
int __init cma_declare_contiguous(phys_addr_t base,
			phys_addr_t size, phys_addr_t limit,
			phys_addr_t alignment, unsigned int order_per_bit,
			bool fixed, struct cma **res_cma)
{
	phys_addr_t memblock_end = memblock_end_of_DRAM();
	phys_addr_t highmem_start;
	int ret = 0;

#ifdef CONFIG_X86
	/*
	 * high_memory isn't direct mapped memory so retrieving its physical
	 * address isn't appropriate.  But it would be useful to check the
	 * physical address of the highmem boundary so it's justfiable to get
	 * the physical address from it.  On x86 there is a validation check for
	 * this case, so the following workaround is needed to avoid it.
	 */
	highmem_start = __pa_nodebug(high_memory);
#else
	highmem_start = __pa(high_memory);
#endif
	pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
		__func__, &size, &base, &limit, &alignment);

	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
		pr_err("Not enough slots for CMA reserved regions!\n");
		return -ENOSPC;
	}

	if (!size)
		return -EINVAL;

	if (alignment && !is_power_of_2(alignment))
		return -EINVAL;

	/*
	 * Sanitise input arguments.
	 * Pages both ends in CMA area could be merged into adjacent unmovable
	 * migratetype page by page allocator's buddy algorithm. In the case,
	 * you couldn't get a contiguous memory, which is not what we want.
	 */
	alignment = max(alignment,
		(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
	base = ALIGN(base, alignment);
	size = ALIGN(size, alignment);
	limit &= ~(alignment - 1);

	if (!base)
		fixed = false;

	/* size should be aligned with order_per_bit */
	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
		return -EINVAL;

	/*
	 * If allocating at a fixed base the request region must not cross the
	 * low/high memory boundary.
	 */
	if (fixed && base < highmem_start && base + size > highmem_start) {
		ret = -EINVAL;
		pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
			&base, &highmem_start);
		goto err;
	}

	/*
	 * If the limit is unspecified or above the memblock end, its effective
	 * value will be the memblock end. Set it explicitly to simplify further
	 * checks.
	 */
	if (limit == 0 || limit > memblock_end)
		limit = memblock_end;

	/* Reserve memory */
	if (fixed) {
		if (memblock_is_region_reserved(base, size) ||
		    memblock_reserve(base, size) < 0) {
			ret = -EBUSY;
			goto err;
		}
	} else {
		phys_addr_t addr = 0;

		/*
		 * All pages in the reserved area must come from the same zone.
		 * If the requested region crosses the low/high memory boundary,
		 * try allocating from high memory first and fall back to low
		 * memory in case of failure.
		 */
		if (base < highmem_start && limit > highmem_start) {
			addr = memblock_alloc_range(size, alignment,
						    highmem_start, limit);
			limit = highmem_start;
		}

		if (!addr) {
			addr = memblock_alloc_range(size, alignment, base,
						    limit);
			if (!addr) {
				ret = -ENOMEM;
				goto err;
			}
		}

		base = addr;
	}

	ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
	if (ret)
		goto err;

	pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
		&base);
	return 0;

err:
	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
	return ret;
}

/**
 * cma_alloc() - allocate pages from contiguous area
 * @cma:   Contiguous memory region for which the allocation is performed.
 * @count: Requested number of pages.
 * @align: Requested alignment of pages (in PAGE_SIZE order).
 *
 * This function allocates part of contiguous memory on specific
 * contiguous memory area.
 */
struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
{
	unsigned long mask, offset, pfn, start = 0;
	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
	struct page *page = NULL;
	int ret;

	if (!cma || !cma->count)
		return NULL;

	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
		 count, align);

	if (!count)
		return NULL;

	mask = cma_bitmap_aligned_mask(cma, align);
	offset = cma_bitmap_aligned_offset(cma, align);
	bitmap_maxno = cma_bitmap_maxno(cma);
	bitmap_count = cma_bitmap_pages_to_bits(cma, count);

	for (;;) {
		mutex_lock(&cma->lock);
		bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
				bitmap_maxno, start, bitmap_count, mask,
				offset);
		if (bitmap_no >= bitmap_maxno) {
			mutex_unlock(&cma->lock);
			break;
		}
		bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
		/*
		 * It's safe to drop the lock here. We've marked this region for
		 * our exclusive use. If the migration fails we will take the
		 * lock again and unmark it.
		 */
		mutex_unlock(&cma->lock);

		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
		mutex_lock(&cma_mutex);
		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
		mutex_unlock(&cma_mutex);
		if (ret == 0) {
			page = pfn_to_page(pfn);
			break;
		}

		cma_clear_bitmap(cma, pfn, count);
		if (ret != -EBUSY)
			break;

		pr_debug("%s(): memory range at %p is busy, retrying\n",
			 __func__, pfn_to_page(pfn));
		/* try again with a bit different memory target */
		start = bitmap_no + mask + 1;
	}

	pr_debug("%s(): returned %p\n", __func__, page);
	return page;
}

/**
 * cma_release() - release allocated pages
 * @cma:   Contiguous memory region for which the allocation is performed.
 * @pages: Allocated pages.
 * @count: Number of allocated pages.
 *
 * This function releases memory allocated by alloc_cma().
 * It returns false when provided pages do not belong to contiguous area and
 * true otherwise.
 */
bool cma_release(struct cma *cma, struct page *pages, int count)
{
	unsigned long pfn;

	if (!cma || !pages)
		return false;

	pr_debug("%s(page %p)\n", __func__, (void *)pages);

	pfn = page_to_pfn(pages);

	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
		return false;

	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);

	free_contig_range(pfn, count);
	cma_clear_bitmap(cma, pfn, count);

	return true;
}
Commit	Line	Data
a254129e JK	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 <[email protected]>
	9	* Michal Nazarewicz <[email protected]>
	10	* Aneesh Kumar K.V <[email protected]>
	11	* Joonsoo Kim <[email protected]>
	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
	27	#include <linux/memblock.h>
	28	#include <linux/err.h>
	29	#include <linux/mm.h>
	30	#include <linux/mutex.h>
	31	#include <linux/sizes.h>
	32	#include <linux/slab.h>
	33	#include <linux/log2.h>
	34	#include <linux/cma.h>
f7426b98	35	#include <linux/highmem.h>
a254129e JK	36
	37	struct cma {
	38	unsigned long base_pfn;
	39	unsigned long count;
	40	unsigned long *bitmap;
	41	unsigned int order_per_bit; /* Order of pages represented by one bit */
	42	struct mutex lock;
	43	};
	44
	45	static struct cma cma_areas[MAX_CMA_AREAS];
	46	static unsigned cma_area_count;
	47	static DEFINE_MUTEX(cma_mutex);
	48
	49	phys_addr_t cma_get_base(struct cma *cma)
	50	{
	51	return PFN_PHYS(cma->base_pfn);
	52	}
	53
	54	unsigned long cma_get_size(struct cma *cma)
	55	{
	56	return cma->count << PAGE_SHIFT;
	57	}
	58
	59	static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
	60	{
68faed63 WY	61	if (align_order <= cma->order_per_bit)
	62	return 0;
	63	return (1UL << (align_order - cma->order_per_bit)) - 1;
a254129e JK	64	}
a254129e JK	65
b5be83e3 GF	66	static unsigned long cma_bitmap_aligned_offset(struct cma *cma, int align_order)
	67	{
	68	unsigned int alignment;
	69
	70	if (align_order <= cma->order_per_bit)
	71	return 0;
	72	alignment = 1UL << (align_order - cma->order_per_bit);
	73	return ALIGN(cma->base_pfn, alignment) -
	74	(cma->base_pfn >> cma->order_per_bit);
	75	}
	76
a254129e JK	77	static unsigned long cma_bitmap_maxno(struct cma *cma)
	78	{
	79	return cma->count >> cma->order_per_bit;
	80	}
	81
	82	static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
	83	unsigned long pages)
	84	{
	85	return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
	86	}
	87
	88	static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count)
	89	{
	90	unsigned long bitmap_no, bitmap_count;
	91
	92	bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
	93	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
	94
	95	mutex_lock(&cma->lock);
	96	bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
	97	mutex_unlock(&cma->lock);
	98	}
	99
	100	static int __init cma_activate_area(struct cma *cma)
	101	{
	102	int bitmap_size = BITS_TO_LONGS(cma_bitmap_maxno(cma)) * sizeof(long);
	103	unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
	104	unsigned i = cma->count >> pageblock_order;
	105	struct zone *zone;
	106
	107	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
	108
	109	if (!cma->bitmap)
	110	return -ENOMEM;
	111
	112	WARN_ON_ONCE(!pfn_valid(pfn));
	113	zone = page_zone(pfn_to_page(pfn));
	114
	115	do {
	116	unsigned j;
	117
	118	base_pfn = pfn;
	119	for (j = pageblock_nr_pages; j; --j, pfn++) {
	120	WARN_ON_ONCE(!pfn_valid(pfn));
	121	/*
	122	* alloc_contig_range requires the pfn range
	123	* specified to be in the same zone. Make this
	124	* simple by forcing the entire CMA resv range
	125	* to be in the same zone.
	126	*/
	127	if (page_zone(pfn_to_page(pfn)) != zone)
	128	goto err;
	129	}
	130	init_cma_reserved_pageblock(pfn_to_page(base_pfn));
	131	} while (--i);
	132
	133	mutex_init(&cma->lock);
	134	return 0;
	135
	136	err:
	137	kfree(cma->bitmap);
f022d8cb	138	cma->count = 0;
a254129e JK	139	return -EINVAL;
	140	}
	141
	142	static int __init cma_init_reserved_areas(void)
	143	{
	144	int i;
	145
	146	for (i = 0; i < cma_area_count; i++) {
	147	int ret = cma_activate_area(&cma_areas[i]);
	148
	149	if (ret)
	150	return ret;
	151	}
	152
	153	return 0;
	154	}
	155	core_initcall(cma_init_reserved_areas);
	156
de9e14ee MS	157	/**
	158	* cma_init_reserved_mem() - create custom contiguous area from reserved memory
	159	* @base: Base address of the reserved area
	160	* @size: Size of the reserved area (in bytes),
	161	* @order_per_bit: Order of pages represented by one bit on bitmap.
	162	* @res_cma: Pointer to store the created cma region.
	163	*
	164	* This function creates custom contiguous area from already reserved memory.
	165	*/
	166	int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
	167	int order_per_bit, struct cma **res_cma)
	168	{
	169	struct cma *cma;
	170	phys_addr_t alignment;
	171
	172	/* Sanity checks */
	173	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
	174	pr_err("Not enough slots for CMA reserved regions!\n");
	175	return -ENOSPC;
	176	}
	177
	178	if (!size \|\| !memblock_is_region_reserved(base, size))
	179	return -EINVAL;
	180
	181	/* ensure minimal alignment requied by mm core */
	182	alignment = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
	183
	184	/* alignment should be aligned with order_per_bit */
	185	if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
	186	return -EINVAL;
	187
	188	if (ALIGN(base, alignment) != base \|\| ALIGN(size, alignment) != size)
	189	return -EINVAL;
	190
	191	/*
	192	* Each reserved area must be initialised later, when more kernel
	193	* subsystems (like slab allocator) are available.
	194	*/
	195	cma = &cma_areas[cma_area_count];
	196	cma->base_pfn = PFN_DOWN(base);
	197	cma->count = size >> PAGE_SHIFT;
	198	cma->order_per_bit = order_per_bit;
	199	*res_cma = cma;
	200	cma_area_count++;
	201
	202	return 0;
	203	}
	204
a254129e JK	205	/**
a254129e JK	206	* cma_declare_contiguous() - reserve custom contiguous area
a254129e	207	* @base: Base address of the reserved area optional, use 0 for any
c1f733aa	208	* @size: Size of the reserved area (in bytes),
a254129e JK	209	* @limit: End address of the reserved memory (optional, 0 for any).
	210	* @alignment: Alignment for the CMA area, should be power of 2 or zero
	211	* @order_per_bit: Order of pages represented by one bit on bitmap.
a254129e	212	* @fixed: hint about where to place the reserved area
c1f733aa	213	* @res_cma: Pointer to store the created cma region.
a254129e JK	214	*
	215	* This function reserves memory from early allocator. It should be
	216	* called by arch specific code once the early allocator (memblock or bootmem)
	217	* has been activated and all other subsystems have already allocated/reserved
	218	* memory. This function allows to create custom reserved areas.
	219	*
	220	* If @fixed is true, reserve contiguous area at exactly @base. If false,
	221	* reserve in range from @base to @limit.
	222	*/
c1f733aa JK	223	int __init cma_declare_contiguous(phys_addr_t base,
c1f733aa JK	224	phys_addr_t size, phys_addr_t limit,
a254129e	225	phys_addr_t alignment, unsigned int order_per_bit,
c1f733aa	226	bool fixed, struct cma **res_cma)
a254129e	227	{
f7426b98	228	phys_addr_t memblock_end = memblock_end_of_DRAM();
6b101e2a	229	phys_addr_t highmem_start;
a254129e JK	230	int ret = 0;
a254129e JK	231
6b101e2a JK	232	#ifdef CONFIG_X86
	233	/*
	234	* high_memory isn't direct mapped memory so retrieving its physical
	235	* address isn't appropriate. But it would be useful to check the
	236	* physical address of the highmem boundary so it's justfiable to get
	237	* the physical address from it. On x86 there is a validation check for
	238	* this case, so the following workaround is needed to avoid it.
	239	*/
	240	highmem_start = __pa_nodebug(high_memory);
	241	#else
	242	highmem_start = __pa(high_memory);
	243	#endif
56fa4f60 LP	244	pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
56fa4f60 LP	245	__func__, &size, &base, &limit, &alignment);
a254129e JK	246
	247	if (cma_area_count == ARRAY_SIZE(cma_areas)) {
	248	pr_err("Not enough slots for CMA reserved regions!\n");
	249	return -ENOSPC;
	250	}
	251
	252	if (!size)
	253	return -EINVAL;
	254
	255	if (alignment && !is_power_of_2(alignment))
	256	return -EINVAL;
	257
	258	/*
	259	* Sanitise input arguments.
	260	* Pages both ends in CMA area could be merged into adjacent unmovable
	261	* migratetype page by page allocator's buddy algorithm. In the case,
	262	* you couldn't get a contiguous memory, which is not what we want.
	263	*/
	264	alignment = max(alignment,
	265	(phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
	266	base = ALIGN(base, alignment);
	267	size = ALIGN(size, alignment);
	268	limit &= ~(alignment - 1);
	269
800a85d3 LP	270	if (!base)
	271	fixed = false;
	272
a254129e JK	273	/* size should be aligned with order_per_bit */
	274	if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
	275	return -EINVAL;
	276
f7426b98	277	/*
16195ddd LP	278	* If allocating at a fixed base the request region must not cross the
16195ddd LP	279	* low/high memory boundary.
f7426b98	280	*/
16195ddd	281	if (fixed && base < highmem_start && base + size > highmem_start) {
f7426b98	282	ret = -EINVAL;
56fa4f60 LP	283	pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
56fa4f60 LP	284	&base, &highmem_start);
f7426b98 MS	285	goto err;
	286	}
	287
16195ddd LP	288	/*
	289	* If the limit is unspecified or above the memblock end, its effective
	290	* value will be the memblock end. Set it explicitly to simplify further
	291	* checks.
	292	*/
	293	if (limit == 0 \|\| limit > memblock_end)
	294	limit = memblock_end;
	295
a254129e	296	/* Reserve memory */
800a85d3	297	if (fixed) {
a254129e JK	298	if (memblock_is_region_reserved(base, size) \|\|
	299	memblock_reserve(base, size) < 0) {
	300	ret = -EBUSY;
	301	goto err;
	302	}
	303	} else {
16195ddd LP	304	phys_addr_t addr = 0;
	305
	306	/*
	307	* All pages in the reserved area must come from the same zone.
	308	* If the requested region crosses the low/high memory boundary,
	309	* try allocating from high memory first and fall back to low
	310	* memory in case of failure.
	311	*/
	312	if (base < highmem_start && limit > highmem_start) {
	313	addr = memblock_alloc_range(size, alignment,
	314	highmem_start, limit);
	315	limit = highmem_start;
	316	}
	317
a254129e	318	if (!addr) {
16195ddd LP	319	addr = memblock_alloc_range(size, alignment, base,
	320	limit);
	321	if (!addr) {
	322	ret = -ENOMEM;
	323	goto err;
	324	}
a254129e	325	}
16195ddd LP	326
16195ddd LP	327	base = addr;
a254129e JK	328	}
a254129e JK	329
de9e14ee MS	330	ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma);
	331	if (ret)
	332	goto err;
a254129e	333
56fa4f60 LP	334	pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
56fa4f60 LP	335	&base);
a254129e JK	336	return 0;
	337
	338	err:
0de9d2eb	339	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
a254129e JK	340	return ret;
	341	}
	342
	343	/**
	344	* cma_alloc() - allocate pages from contiguous area
	345	* @cma: Contiguous memory region for which the allocation is performed.
	346	* @count: Requested number of pages.
	347	* @align: Requested alignment of pages (in PAGE_SIZE order).
	348	*
	349	* This function allocates part of contiguous memory on specific
	350	* contiguous memory area.
	351	*/
	352	struct page cma_alloc(struct cma cma, int count, unsigned int align)
	353	{
b5be83e3	354	unsigned long mask, offset, pfn, start = 0;
a254129e JK	355	unsigned long bitmap_maxno, bitmap_no, bitmap_count;
	356	struct page *page = NULL;
	357	int ret;
	358
	359	if (!cma \|\| !cma->count)
	360	return NULL;
	361
	362	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
	363	count, align);
	364
	365	if (!count)
	366	return NULL;
	367
	368	mask = cma_bitmap_aligned_mask(cma, align);
b5be83e3	369	offset = cma_bitmap_aligned_offset(cma, align);
a254129e JK	370	bitmap_maxno = cma_bitmap_maxno(cma);
	371	bitmap_count = cma_bitmap_pages_to_bits(cma, count);
	372
	373	for (;;) {
	374	mutex_lock(&cma->lock);
b5be83e3 GF	375	bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
	376	bitmap_maxno, start, bitmap_count, mask,
	377	offset);
a254129e JK	378	if (bitmap_no >= bitmap_maxno) {
	379	mutex_unlock(&cma->lock);
	380	break;
	381	}
	382	bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
	383	/*
	384	* It's safe to drop the lock here. We've marked this region for
	385	* our exclusive use. If the migration fails we will take the
	386	* lock again and unmark it.
	387	*/
	388	mutex_unlock(&cma->lock);
	389
	390	pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
	391	mutex_lock(&cma_mutex);
	392	ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
	393	mutex_unlock(&cma_mutex);
	394	if (ret == 0) {
	395	page = pfn_to_page(pfn);
	396	break;
a254129e	397	}
b7155e76	398
a254129e	399	cma_clear_bitmap(cma, pfn, count);
b7155e76 JK	400	if (ret != -EBUSY)
	401	break;
	402
a254129e JK	403	pr_debug("%s(): memory range at %p is busy, retrying\n",
	404	__func__, pfn_to_page(pfn));
	405	/* try again with a bit different memory target */
	406	start = bitmap_no + mask + 1;
	407	}
	408
	409	pr_debug("%s(): returned %p\n", __func__, page);
	410	return page;
	411	}
	412
	413	/**
	414	* cma_release() - release allocated pages
	415	* @cma: Contiguous memory region for which the allocation is performed.
	416	* @pages: Allocated pages.
	417	* @count: Number of allocated pages.
	418	*
	419	* This function releases memory allocated by alloc_cma().
	420	* It returns false when provided pages do not belong to contiguous area and
	421	* true otherwise.
	422	*/
	423	bool cma_release(struct cma cma, struct page pages, int count)
	424	{
	425	unsigned long pfn;
	426
	427	if (!cma \|\| !pages)
	428	return false;
	429
	430	pr_debug("%s(page %p)\n", __func__, (void *)pages);
	431
	432	pfn = page_to_pfn(pages);
	433
	434	if (pfn < cma->base_pfn \|\| pfn >= cma->base_pfn + cma->count)
	435	return false;
	436
	437	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
	438
	439	free_contig_range(pfn, count);
	440	cma_clear_bitmap(cma, pfn, count);
	441
	442	return true;
	443	}