2 * Contiguous Memory Allocator
4 * Copyright (c) 2010-2011 by Samsung Electronics.
5 * Copyright IBM Corporation, 2013
6 * Copyright LG Electronics Inc., 2014
8 * Marek Szyprowski <m.szyprowski@samsung.com>
9 * Michal Nazarewicz <mina86@mina86.com>
10 * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
11 * Joonsoo Kim <iamjoonsoo.kim@lge.com>
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.
19 #define pr_fmt(fmt) "cma: " fmt
21 #ifdef CONFIG_CMA_DEBUG
27 #include <linux/memblock.h>
28 #include <linux/err.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>
35 #include <linux/highmem.h>
38 unsigned long base_pfn
;
40 unsigned long *bitmap
;
41 unsigned int order_per_bit
; /* Order of pages represented by one bit */
45 static struct cma cma_areas
[MAX_CMA_AREAS
];
46 static unsigned cma_area_count
;
47 static DEFINE_MUTEX(cma_mutex
);
49 phys_addr_t
cma_get_base(struct cma
*cma
)
51 return PFN_PHYS(cma
->base_pfn
);
54 unsigned long cma_get_size(struct cma
*cma
)
56 return cma
->count
<< PAGE_SHIFT
;
59 static unsigned long cma_bitmap_aligned_mask(struct cma
*cma
, int align_order
)
61 return (1UL << (align_order
>> cma
->order_per_bit
)) - 1;
64 static unsigned long cma_bitmap_maxno(struct cma
*cma
)
66 return cma
->count
>> cma
->order_per_bit
;
69 static unsigned long cma_bitmap_pages_to_bits(struct cma
*cma
,
72 return ALIGN(pages
, 1UL << cma
->order_per_bit
) >> cma
->order_per_bit
;
75 static void cma_clear_bitmap(struct cma
*cma
, unsigned long pfn
, int count
)
77 unsigned long bitmap_no
, bitmap_count
;
79 bitmap_no
= (pfn
- cma
->base_pfn
) >> cma
->order_per_bit
;
80 bitmap_count
= cma_bitmap_pages_to_bits(cma
, count
);
82 mutex_lock(&cma
->lock
);
83 bitmap_clear(cma
->bitmap
, bitmap_no
, bitmap_count
);
84 mutex_unlock(&cma
->lock
);
87 static int __init
cma_activate_area(struct cma
*cma
)
89 int bitmap_size
= BITS_TO_LONGS(cma_bitmap_maxno(cma
)) * sizeof(long);
90 unsigned long base_pfn
= cma
->base_pfn
, pfn
= base_pfn
;
91 unsigned i
= cma
->count
>> pageblock_order
;
94 cma
->bitmap
= kzalloc(bitmap_size
, GFP_KERNEL
);
99 WARN_ON_ONCE(!pfn_valid(pfn
));
100 zone
= page_zone(pfn_to_page(pfn
));
106 for (j
= pageblock_nr_pages
; j
; --j
, pfn
++) {
107 WARN_ON_ONCE(!pfn_valid(pfn
));
109 * alloc_contig_range requires the pfn range
110 * specified to be in the same zone. Make this
111 * simple by forcing the entire CMA resv range
112 * to be in the same zone.
114 if (page_zone(pfn_to_page(pfn
)) != zone
)
117 init_cma_reserved_pageblock(pfn_to_page(base_pfn
));
120 mutex_init(&cma
->lock
);
128 static int __init
cma_init_reserved_areas(void)
132 for (i
= 0; i
< cma_area_count
; i
++) {
133 int ret
= cma_activate_area(&cma_areas
[i
]);
141 core_initcall(cma_init_reserved_areas
);
144 * cma_declare_contiguous() - reserve custom contiguous area
145 * @base: Base address of the reserved area optional, use 0 for any
146 * @size: Size of the reserved area (in bytes),
147 * @limit: End address of the reserved memory (optional, 0 for any).
148 * @alignment: Alignment for the CMA area, should be power of 2 or zero
149 * @order_per_bit: Order of pages represented by one bit on bitmap.
150 * @fixed: hint about where to place the reserved area
151 * @res_cma: Pointer to store the created cma region.
153 * This function reserves memory from early allocator. It should be
154 * called by arch specific code once the early allocator (memblock or bootmem)
155 * has been activated and all other subsystems have already allocated/reserved
156 * memory. This function allows to create custom reserved areas.
158 * If @fixed is true, reserve contiguous area at exactly @base. If false,
159 * reserve in range from @base to @limit.
161 int __init
cma_declare_contiguous(phys_addr_t base
,
162 phys_addr_t size
, phys_addr_t limit
,
163 phys_addr_t alignment
, unsigned int order_per_bit
,
164 bool fixed
, struct cma
**res_cma
)
167 phys_addr_t memblock_end
= memblock_end_of_DRAM();
168 phys_addr_t highmem_start
= __pa(high_memory
);
171 pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
172 __func__
, (unsigned long)size
, (unsigned long)base
,
173 (unsigned long)limit
, (unsigned long)alignment
);
175 if (cma_area_count
== ARRAY_SIZE(cma_areas
)) {
176 pr_err("Not enough slots for CMA reserved regions!\n");
183 if (alignment
&& !is_power_of_2(alignment
))
187 * Sanitise input arguments.
188 * Pages both ends in CMA area could be merged into adjacent unmovable
189 * migratetype page by page allocator's buddy algorithm. In the case,
190 * you couldn't get a contiguous memory, which is not what we want.
192 alignment
= max(alignment
,
193 (phys_addr_t
)PAGE_SIZE
<< max(MAX_ORDER
- 1, pageblock_order
));
194 base
= ALIGN(base
, alignment
);
195 size
= ALIGN(size
, alignment
);
196 limit
&= ~(alignment
- 1);
198 /* size should be aligned with order_per_bit */
199 if (!IS_ALIGNED(size
>> PAGE_SHIFT
, 1 << order_per_bit
))
203 * adjust limit to avoid crossing low/high memory boundary for
204 * automatically allocated regions
206 if (((limit
== 0 || limit
> memblock_end
) &&
207 (memblock_end
- size
< highmem_start
&&
208 memblock_end
> highmem_start
)) ||
209 (!fixed
&& limit
> highmem_start
&& limit
- size
< highmem_start
)) {
210 limit
= highmem_start
;
213 if (fixed
&& base
< highmem_start
&& base
+size
> highmem_start
) {
215 pr_err("Region at %08lx defined on low/high memory boundary (%08lx)\n",
216 (unsigned long)base
, (unsigned long)highmem_start
);
222 if (memblock_is_region_reserved(base
, size
) ||
223 memblock_reserve(base
, size
) < 0) {
228 phys_addr_t addr
= memblock_alloc_range(size
, alignment
, base
,
239 * Each reserved area must be initialised later, when more kernel
240 * subsystems (like slab allocator) are available.
242 cma
= &cma_areas
[cma_area_count
];
243 cma
->base_pfn
= PFN_DOWN(base
);
244 cma
->count
= size
>> PAGE_SHIFT
;
245 cma
->order_per_bit
= order_per_bit
;
249 pr_info("Reserved %ld MiB at %08lx\n", (unsigned long)size
/ SZ_1M
,
250 (unsigned long)base
);
254 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size
/ SZ_1M
);
259 * cma_alloc() - allocate pages from contiguous area
260 * @cma: Contiguous memory region for which the allocation is performed.
261 * @count: Requested number of pages.
262 * @align: Requested alignment of pages (in PAGE_SIZE order).
264 * This function allocates part of contiguous memory on specific
265 * contiguous memory area.
267 struct page
*cma_alloc(struct cma
*cma
, int count
, unsigned int align
)
269 unsigned long mask
, pfn
, start
= 0;
270 unsigned long bitmap_maxno
, bitmap_no
, bitmap_count
;
271 struct page
*page
= NULL
;
274 if (!cma
|| !cma
->count
)
277 pr_debug("%s(cma %p, count %d, align %d)\n", __func__
, (void *)cma
,
283 mask
= cma_bitmap_aligned_mask(cma
, align
);
284 bitmap_maxno
= cma_bitmap_maxno(cma
);
285 bitmap_count
= cma_bitmap_pages_to_bits(cma
, count
);
288 mutex_lock(&cma
->lock
);
289 bitmap_no
= bitmap_find_next_zero_area(cma
->bitmap
,
290 bitmap_maxno
, start
, bitmap_count
, mask
);
291 if (bitmap_no
>= bitmap_maxno
) {
292 mutex_unlock(&cma
->lock
);
295 bitmap_set(cma
->bitmap
, bitmap_no
, bitmap_count
);
297 * It's safe to drop the lock here. We've marked this region for
298 * our exclusive use. If the migration fails we will take the
299 * lock again and unmark it.
301 mutex_unlock(&cma
->lock
);
303 pfn
= cma
->base_pfn
+ (bitmap_no
<< cma
->order_per_bit
);
304 mutex_lock(&cma_mutex
);
305 ret
= alloc_contig_range(pfn
, pfn
+ count
, MIGRATE_CMA
);
306 mutex_unlock(&cma_mutex
);
308 page
= pfn_to_page(pfn
);
312 cma_clear_bitmap(cma
, pfn
, count
);
316 pr_debug("%s(): memory range at %p is busy, retrying\n",
317 __func__
, pfn_to_page(pfn
));
318 /* try again with a bit different memory target */
319 start
= bitmap_no
+ mask
+ 1;
322 pr_debug("%s(): returned %p\n", __func__
, page
);
327 * cma_release() - release allocated pages
328 * @cma: Contiguous memory region for which the allocation is performed.
329 * @pages: Allocated pages.
330 * @count: Number of allocated pages.
332 * This function releases memory allocated by alloc_cma().
333 * It returns false when provided pages do not belong to contiguous area and
336 bool cma_release(struct cma
*cma
, struct page
*pages
, int count
)
343 pr_debug("%s(page %p)\n", __func__
, (void *)pages
);
345 pfn
= page_to_pfn(pages
);
347 if (pfn
< cma
->base_pfn
|| pfn
>= cma
->base_pfn
+ cma
->count
)
350 VM_BUG_ON(pfn
+ count
> cma
->base_pfn
+ cma
->count
);
352 free_contig_range(pfn
, count
);
353 cma_clear_bitmap(cma
, pfn
, count
);