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
26 #define CREATE_TRACE_POINTS
28 #include <linux/memblock.h>
29 #include <linux/err.h>
31 #include <linux/mutex.h>
32 #include <linux/sizes.h>
33 #include <linux/slab.h>
34 #include <linux/log2.h>
35 #include <linux/cma.h>
36 #include <linux/highmem.h>
38 #include <linux/kmemleak.h>
39 #include <trace/events/cma.h>
43 struct cma cma_areas
[MAX_CMA_AREAS
];
44 unsigned cma_area_count
;
45 static DEFINE_MUTEX(cma_mutex
);
47 phys_addr_t
cma_get_base(const struct cma
*cma
)
49 return PFN_PHYS(cma
->base_pfn
);
52 unsigned long cma_get_size(const struct cma
*cma
)
54 return cma
->count
<< PAGE_SHIFT
;
57 const char *cma_get_name(const struct cma
*cma
)
59 return cma
->name
? cma
->name
: "(undefined)";
62 static unsigned long cma_bitmap_aligned_mask(const struct cma
*cma
,
63 unsigned int align_order
)
65 if (align_order
<= cma
->order_per_bit
)
67 return (1UL << (align_order
- cma
->order_per_bit
)) - 1;
71 * Find the offset of the base PFN from the specified align_order.
72 * The value returned is represented in order_per_bits.
74 static unsigned long cma_bitmap_aligned_offset(const struct cma
*cma
,
75 unsigned int align_order
)
77 return (cma
->base_pfn
& ((1UL << align_order
) - 1))
78 >> cma
->order_per_bit
;
81 static unsigned long cma_bitmap_pages_to_bits(const struct cma
*cma
,
84 return ALIGN(pages
, 1UL << cma
->order_per_bit
) >> cma
->order_per_bit
;
87 static void cma_clear_bitmap(struct cma
*cma
, unsigned long pfn
,
90 unsigned long bitmap_no
, bitmap_count
;
92 bitmap_no
= (pfn
- cma
->base_pfn
) >> cma
->order_per_bit
;
93 bitmap_count
= cma_bitmap_pages_to_bits(cma
, count
);
95 mutex_lock(&cma
->lock
);
96 bitmap_clear(cma
->bitmap
, bitmap_no
, bitmap_count
);
97 mutex_unlock(&cma
->lock
);
100 static int __init
cma_activate_area(struct cma
*cma
)
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
;
107 cma
->bitmap
= kzalloc(bitmap_size
, GFP_KERNEL
);
114 WARN_ON_ONCE(!pfn_valid(pfn
));
115 zone
= page_zone(pfn_to_page(pfn
));
121 for (j
= pageblock_nr_pages
; j
; --j
, pfn
++) {
122 WARN_ON_ONCE(!pfn_valid(pfn
));
124 * alloc_contig_range requires the pfn range
125 * specified to be in the same zone. Make this
126 * simple by forcing the entire CMA resv range
127 * to be in the same zone.
129 if (page_zone(pfn_to_page(pfn
)) != zone
)
132 init_cma_reserved_pageblock(pfn_to_page(base_pfn
));
135 mutex_init(&cma
->lock
);
137 #ifdef CONFIG_CMA_DEBUGFS
138 INIT_HLIST_HEAD(&cma
->mem_head
);
139 spin_lock_init(&cma
->mem_head_lock
);
145 pr_err("CMA area %s could not be activated\n", cma
->name
);
151 static int __init
cma_init_reserved_areas(void)
155 for (i
= 0; i
< cma_area_count
; i
++) {
156 int ret
= cma_activate_area(&cma_areas
[i
]);
164 core_initcall(cma_init_reserved_areas
);
167 * cma_init_reserved_mem() - create custom contiguous area from reserved memory
168 * @base: Base address of the reserved area
169 * @size: Size of the reserved area (in bytes),
170 * @order_per_bit: Order of pages represented by one bit on bitmap.
171 * @name: The name of the area. If this parameter is NULL, the name of
172 * the area will be set to "cmaN", where N is a running counter of
174 * @res_cma: Pointer to store the created cma region.
176 * This function creates custom contiguous area from already reserved memory.
178 int __init
cma_init_reserved_mem(phys_addr_t base
, phys_addr_t size
,
179 unsigned int order_per_bit
,
181 struct cma
**res_cma
)
184 phys_addr_t alignment
;
187 if (cma_area_count
== ARRAY_SIZE(cma_areas
)) {
188 pr_err("Not enough slots for CMA reserved regions!\n");
192 if (!size
|| !memblock_is_region_reserved(base
, size
))
195 /* ensure minimal alignment required by mm core */
196 alignment
= PAGE_SIZE
<<
197 max_t(unsigned long, MAX_ORDER
- 1, pageblock_order
);
199 /* alignment should be aligned with order_per_bit */
200 if (!IS_ALIGNED(alignment
>> PAGE_SHIFT
, 1 << order_per_bit
))
203 if (ALIGN(base
, alignment
) != base
|| ALIGN(size
, alignment
) != size
)
207 * Each reserved area must be initialised later, when more kernel
208 * subsystems (like slab allocator) are available.
210 cma
= &cma_areas
[cma_area_count
];
214 cma
->name
= kasprintf(GFP_KERNEL
, "cma%d\n", cma_area_count
);
218 cma
->base_pfn
= PFN_DOWN(base
);
219 cma
->count
= size
>> PAGE_SHIFT
;
220 cma
->order_per_bit
= order_per_bit
;
223 totalcma_pages
+= (size
/ PAGE_SIZE
);
229 * cma_declare_contiguous() - reserve custom contiguous area
230 * @base: Base address of the reserved area optional, use 0 for any
231 * @size: Size of the reserved area (in bytes),
232 * @limit: End address of the reserved memory (optional, 0 for any).
233 * @alignment: Alignment for the CMA area, should be power of 2 or zero
234 * @order_per_bit: Order of pages represented by one bit on bitmap.
235 * @fixed: hint about where to place the reserved area
236 * @name: The name of the area. See function cma_init_reserved_mem()
237 * @res_cma: Pointer to store the created cma region.
239 * This function reserves memory from early allocator. It should be
240 * called by arch specific code once the early allocator (memblock or bootmem)
241 * has been activated and all other subsystems have already allocated/reserved
242 * memory. This function allows to create custom reserved areas.
244 * If @fixed is true, reserve contiguous area at exactly @base. If false,
245 * reserve in range from @base to @limit.
247 int __init
cma_declare_contiguous(phys_addr_t base
,
248 phys_addr_t size
, phys_addr_t limit
,
249 phys_addr_t alignment
, unsigned int order_per_bit
,
250 bool fixed
, const char *name
, struct cma
**res_cma
)
252 phys_addr_t memblock_end
= memblock_end_of_DRAM();
253 phys_addr_t highmem_start
;
257 * We can't use __pa(high_memory) directly, since high_memory
258 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
259 * complain. Find the boundary by adding one to the last valid
262 highmem_start
= __pa(high_memory
- 1) + 1;
263 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
264 __func__
, &size
, &base
, &limit
, &alignment
);
266 if (cma_area_count
== ARRAY_SIZE(cma_areas
)) {
267 pr_err("Not enough slots for CMA reserved regions!\n");
274 if (alignment
&& !is_power_of_2(alignment
))
278 * Sanitise input arguments.
279 * Pages both ends in CMA area could be merged into adjacent unmovable
280 * migratetype page by page allocator's buddy algorithm. In the case,
281 * you couldn't get a contiguous memory, which is not what we want.
283 alignment
= max(alignment
, (phys_addr_t
)PAGE_SIZE
<<
284 max_t(unsigned long, MAX_ORDER
- 1, pageblock_order
));
285 base
= ALIGN(base
, alignment
);
286 size
= ALIGN(size
, alignment
);
287 limit
&= ~(alignment
- 1);
292 /* size should be aligned with order_per_bit */
293 if (!IS_ALIGNED(size
>> PAGE_SHIFT
, 1 << order_per_bit
))
297 * If allocating at a fixed base the request region must not cross the
298 * low/high memory boundary.
300 if (fixed
&& base
< highmem_start
&& base
+ size
> highmem_start
) {
302 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
303 &base
, &highmem_start
);
308 * If the limit is unspecified or above the memblock end, its effective
309 * value will be the memblock end. Set it explicitly to simplify further
312 if (limit
== 0 || limit
> memblock_end
)
313 limit
= memblock_end
;
317 if (memblock_is_region_reserved(base
, size
) ||
318 memblock_reserve(base
, size
) < 0) {
323 phys_addr_t addr
= 0;
326 * All pages in the reserved area must come from the same zone.
327 * If the requested region crosses the low/high memory boundary,
328 * try allocating from high memory first and fall back to low
329 * memory in case of failure.
331 if (base
< highmem_start
&& limit
> highmem_start
) {
332 addr
= memblock_phys_alloc_range(size
, alignment
,
333 highmem_start
, limit
);
334 limit
= highmem_start
;
338 addr
= memblock_phys_alloc_range(size
, alignment
, base
,
347 * kmemleak scans/reads tracked objects for pointers to other
348 * objects but this address isn't mapped and accessible
350 kmemleak_ignore_phys(addr
);
354 ret
= cma_init_reserved_mem(base
, size
, order_per_bit
, name
, res_cma
);
358 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size
/ SZ_1M
,
363 memblock_free(base
, size
);
365 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size
/ SZ_1M
);
369 #ifdef CONFIG_CMA_DEBUG
370 static void cma_debug_show_areas(struct cma
*cma
)
372 unsigned long next_zero_bit
, next_set_bit
, nr_zero
;
373 unsigned long start
= 0;
374 unsigned long nr_part
, nr_total
= 0;
375 unsigned long nbits
= cma_bitmap_maxno(cma
);
377 mutex_lock(&cma
->lock
);
378 pr_info("number of available pages: ");
380 next_zero_bit
= find_next_zero_bit(cma
->bitmap
, nbits
, start
);
381 if (next_zero_bit
>= nbits
)
383 next_set_bit
= find_next_bit(cma
->bitmap
, nbits
, next_zero_bit
);
384 nr_zero
= next_set_bit
- next_zero_bit
;
385 nr_part
= nr_zero
<< cma
->order_per_bit
;
386 pr_cont("%s%lu@%lu", nr_total
? "+" : "", nr_part
,
389 start
= next_zero_bit
+ nr_zero
;
391 pr_cont("=> %lu free of %lu total pages\n", nr_total
, cma
->count
);
392 mutex_unlock(&cma
->lock
);
395 static inline void cma_debug_show_areas(struct cma
*cma
) { }
399 * cma_alloc() - allocate pages from contiguous area
400 * @cma: Contiguous memory region for which the allocation is performed.
401 * @count: Requested number of pages.
402 * @align: Requested alignment of pages (in PAGE_SIZE order).
403 * @no_warn: Avoid printing message about failed allocation
405 * This function allocates part of contiguous memory on specific
406 * contiguous memory area.
408 struct page
*cma_alloc(struct cma
*cma
, size_t count
, unsigned int align
,
411 unsigned long mask
, offset
;
412 unsigned long pfn
= -1;
413 unsigned long start
= 0;
414 unsigned long bitmap_maxno
, bitmap_no
, bitmap_count
;
416 struct page
*page
= NULL
;
419 if (!cma
|| !cma
->count
)
422 pr_debug("%s(cma %p, count %zu, align %d)\n", __func__
, (void *)cma
,
428 mask
= cma_bitmap_aligned_mask(cma
, align
);
429 offset
= cma_bitmap_aligned_offset(cma
, align
);
430 bitmap_maxno
= cma_bitmap_maxno(cma
);
431 bitmap_count
= cma_bitmap_pages_to_bits(cma
, count
);
433 if (bitmap_count
> bitmap_maxno
)
437 mutex_lock(&cma
->lock
);
438 bitmap_no
= bitmap_find_next_zero_area_off(cma
->bitmap
,
439 bitmap_maxno
, start
, bitmap_count
, mask
,
441 if (bitmap_no
>= bitmap_maxno
) {
442 mutex_unlock(&cma
->lock
);
445 bitmap_set(cma
->bitmap
, bitmap_no
, bitmap_count
);
447 * It's safe to drop the lock here. We've marked this region for
448 * our exclusive use. If the migration fails we will take the
449 * lock again and unmark it.
451 mutex_unlock(&cma
->lock
);
453 pfn
= cma
->base_pfn
+ (bitmap_no
<< cma
->order_per_bit
);
454 mutex_lock(&cma_mutex
);
455 ret
= alloc_contig_range(pfn
, pfn
+ count
, MIGRATE_CMA
,
456 GFP_KERNEL
| (no_warn
? __GFP_NOWARN
: 0));
457 mutex_unlock(&cma_mutex
);
459 page
= pfn_to_page(pfn
);
463 cma_clear_bitmap(cma
, pfn
, count
);
467 pr_debug("%s(): memory range at %p is busy, retrying\n",
468 __func__
, pfn_to_page(pfn
));
469 /* try again with a bit different memory target */
470 start
= bitmap_no
+ mask
+ 1;
473 trace_cma_alloc(pfn
, page
, count
, align
);
476 * CMA can allocate multiple page blocks, which results in different
477 * blocks being marked with different tags. Reset the tags to ignore
481 for (i
= 0; i
< count
; i
++)
482 page_kasan_tag_reset(page
+ i
);
485 if (ret
&& !no_warn
) {
486 pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n",
487 __func__
, count
, ret
);
488 cma_debug_show_areas(cma
);
491 pr_debug("%s(): returned %p\n", __func__
, page
);
496 * cma_release() - release allocated pages
497 * @cma: Contiguous memory region for which the allocation is performed.
498 * @pages: Allocated pages.
499 * @count: Number of allocated pages.
501 * This function releases memory allocated by alloc_cma().
502 * It returns false when provided pages do not belong to contiguous area and
505 bool cma_release(struct cma
*cma
, const struct page
*pages
, unsigned int count
)
512 pr_debug("%s(page %p)\n", __func__
, (void *)pages
);
514 pfn
= page_to_pfn(pages
);
516 if (pfn
< cma
->base_pfn
|| pfn
>= cma
->base_pfn
+ cma
->count
)
519 VM_BUG_ON(pfn
+ count
> cma
->base_pfn
+ cma
->count
);
521 free_contig_range(pfn
, count
);
522 cma_clear_bitmap(cma
, pfn
, count
);
523 trace_cma_release(pfn
, pages
, count
);
528 int cma_for_each_area(int (*it
)(struct cma
*cma
, void *data
), void *data
)
532 for (i
= 0; i
< cma_area_count
; i
++) {
533 int ret
= it(&cma_areas
[i
], data
);