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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Contiguous Memory Allocator4 *5 * Copyright (c) 2010-2011 by Samsung Electronics.6 * Copyright IBM Corporation, 20137 * Copyright LG Electronics Inc., 20148 * 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: " fmt16 17#define CREATE_TRACE_POINTS18 19#include <linux/memblock.h>20#include <linux/err.h>21#include <linux/mm.h>22#include <linux/sizes.h>23#include <linux/slab.h>24#include <linux/log2.h>25#include <linux/cma.h>26#include <linux/highmem.h>27#include <linux/io.h>28#include <linux/kmemleak.h>29#include <trace/events/cma.h>30 31#include "internal.h"32#include "cma.h"33 34struct cma cma_areas[MAX_CMA_AREAS];35unsigned cma_area_count;36static DEFINE_MUTEX(cma_mutex);37 38phys_addr_t cma_get_base(const struct cma *cma)39{40 return PFN_PHYS(cma->base_pfn);41}42 43unsigned long cma_get_size(const struct cma *cma)44{45 return cma->count << PAGE_SHIFT;46}47 48const char *cma_get_name(const struct cma *cma)49{50 return cma->name;51}52 53static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,54 unsigned int align_order)55{56 if (align_order <= cma->order_per_bit)57 return 0;58 return (1UL << (align_order - cma->order_per_bit)) - 1;59}60 61/*62 * Find the offset of the base PFN from the specified align_order.63 * The value returned is represented in order_per_bits.64 */65static unsigned long cma_bitmap_aligned_offset(const struct cma *cma,66 unsigned int align_order)67{68 return (cma->base_pfn & ((1UL << align_order) - 1))69 >> cma->order_per_bit;70}71 72static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma,73 unsigned long pages)74{75 return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;76}77 78static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,79 unsigned long count)80{81 unsigned long bitmap_no, bitmap_count;82 unsigned long flags;83 84 bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;85 bitmap_count = cma_bitmap_pages_to_bits(cma, count);86 87 spin_lock_irqsave(&cma->lock, flags);88 bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);89 spin_unlock_irqrestore(&cma->lock, flags);90}91 92static void __init cma_activate_area(struct cma *cma)93{94 unsigned long base_pfn = cma->base_pfn, pfn;95 struct zone *zone;96 97 cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL);98 if (!cma->bitmap)99 goto out_error;100 101 /*102 * alloc_contig_range() requires the pfn range specified to be in the103 * same zone. Simplify by forcing the entire CMA resv range to be in the104 * same zone.105 */106 WARN_ON_ONCE(!pfn_valid(base_pfn));107 zone = page_zone(pfn_to_page(base_pfn));108 for (pfn = base_pfn + 1; pfn < base_pfn + cma->count; pfn++) {109 WARN_ON_ONCE(!pfn_valid(pfn));110 if (page_zone(pfn_to_page(pfn)) != zone)111 goto not_in_zone;112 }113 114 for (pfn = base_pfn; pfn < base_pfn + cma->count;115 pfn += pageblock_nr_pages)116 init_cma_reserved_pageblock(pfn_to_page(pfn));117 118 spin_lock_init(&cma->lock);119 120#ifdef CONFIG_CMA_DEBUGFS121 INIT_HLIST_HEAD(&cma->mem_head);122 spin_lock_init(&cma->mem_head_lock);123#endif124 125 return;126 127not_in_zone:128 bitmap_free(cma->bitmap);129out_error:130 /* Expose all pages to the buddy, they are useless for CMA. */131 if (!cma->reserve_pages_on_error) {132 for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++)133 free_reserved_page(pfn_to_page(pfn));134 }135 totalcma_pages -= cma->count;136 cma->count = 0;137 pr_err("CMA area %s could not be activated\n", cma->name);138 return;139}140 141static int __init cma_init_reserved_areas(void)142{143 int i;144 145 for (i = 0; i < cma_area_count; i++)146 cma_activate_area(&cma_areas[i]);147 148 return 0;149}150core_initcall(cma_init_reserved_areas);151 152void __init cma_reserve_pages_on_error(struct cma *cma)153{154 cma->reserve_pages_on_error = true;155}156 157/**158 * cma_init_reserved_mem() - create custom contiguous area from reserved memory159 * @base: Base address of the reserved area160 * @size: Size of the reserved area (in bytes),161 * @order_per_bit: Order of pages represented by one bit on bitmap.162 * @name: The name of the area. If this parameter is NULL, the name of163 * the area will be set to "cmaN", where N is a running counter of164 * used areas.165 * @res_cma: Pointer to store the created cma region.166 *167 * This function creates custom contiguous area from already reserved memory.168 */169int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,170 unsigned int order_per_bit,171 const char *name,172 struct cma **res_cma)173{174 struct cma *cma;175 176 /* Sanity checks */177 if (cma_area_count == ARRAY_SIZE(cma_areas)) {178 pr_err("Not enough slots for CMA reserved regions!\n");179 return -ENOSPC;180 }181 182 if (!size || !memblock_is_region_reserved(base, size))183 return -EINVAL;184 185 /* ensure minimal alignment required by mm core */186 if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES))187 return -EINVAL;188 189 /*190 * Each reserved area must be initialised later, when more kernel191 * subsystems (like slab allocator) are available.192 */193 cma = &cma_areas[cma_area_count];194 195 if (name)196 snprintf(cma->name, CMA_MAX_NAME, name);197 else198 snprintf(cma->name, CMA_MAX_NAME, "cma%d\n", cma_area_count);199 200 cma->base_pfn = PFN_DOWN(base);201 cma->count = size >> PAGE_SHIFT;202 cma->order_per_bit = order_per_bit;203 *res_cma = cma;204 cma_area_count++;205 totalcma_pages += cma->count;206 207 return 0;208}209 210/**211 * cma_declare_contiguous_nid() - reserve custom contiguous area212 * @base: Base address of the reserved area optional, use 0 for any213 * @size: Size of the reserved area (in bytes),214 * @limit: End address of the reserved memory (optional, 0 for any).215 * @alignment: Alignment for the CMA area, should be power of 2 or zero216 * @order_per_bit: Order of pages represented by one bit on bitmap.217 * @fixed: hint about where to place the reserved area218 * @name: The name of the area. See function cma_init_reserved_mem()219 * @res_cma: Pointer to store the created cma region.220 * @nid: nid of the free area to find, %NUMA_NO_NODE for any node221 *222 * This function reserves memory from early allocator. It should be223 * called by arch specific code once the early allocator (memblock or bootmem)224 * has been activated and all other subsystems have already allocated/reserved225 * memory. This function allows to create custom reserved areas.226 *227 * If @fixed is true, reserve contiguous area at exactly @base. If false,228 * reserve in range from @base to @limit.229 */230int __init cma_declare_contiguous_nid(phys_addr_t base,231 phys_addr_t size, phys_addr_t limit,232 phys_addr_t alignment, unsigned int order_per_bit,233 bool fixed, const char *name, struct cma **res_cma,234 int nid)235{236 phys_addr_t memblock_end = memblock_end_of_DRAM();237 phys_addr_t highmem_start;238 int ret;239 240 /*241 * We can't use __pa(high_memory) directly, since high_memory242 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)243 * complain. Find the boundary by adding one to the last valid244 * address.245 */246 highmem_start = __pa(high_memory - 1) + 1;247 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",248 __func__, &size, &base, &limit, &alignment);249 250 if (cma_area_count == ARRAY_SIZE(cma_areas)) {251 pr_err("Not enough slots for CMA reserved regions!\n");252 return -ENOSPC;253 }254 255 if (!size)256 return -EINVAL;257 258 if (alignment && !is_power_of_2(alignment))259 return -EINVAL;260 261 if (!IS_ENABLED(CONFIG_NUMA))262 nid = NUMA_NO_NODE;263 264 /* Sanitise input arguments. */265 alignment = max_t(phys_addr_t, alignment, CMA_MIN_ALIGNMENT_BYTES);266 if (fixed && base & (alignment - 1)) {267 ret = -EINVAL;268 pr_err("Region at %pa must be aligned to %pa bytes\n",269 &base, &alignment);270 goto err;271 }272 base = ALIGN(base, alignment);273 size = ALIGN(size, alignment);274 limit &= ~(alignment - 1);275 276 if (!base)277 fixed = false;278 279 /* size should be aligned with order_per_bit */280 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))281 return -EINVAL;282 283 /*284 * If allocating at a fixed base the request region must not cross the285 * low/high memory boundary.286 */287 if (fixed && base < highmem_start && base + size > highmem_start) {288 ret = -EINVAL;289 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",290 &base, &highmem_start);291 goto err;292 }293 294 /*295 * If the limit is unspecified or above the memblock end, its effective296 * value will be the memblock end. Set it explicitly to simplify further297 * checks.298 */299 if (limit == 0 || limit > memblock_end)300 limit = memblock_end;301 302 if (base + size > limit) {303 ret = -EINVAL;304 pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",305 &size, &base, &limit);306 goto err;307 }308 309 /* Reserve memory */310 if (fixed) {311 if (memblock_is_region_reserved(base, size) ||312 memblock_reserve(base, size) < 0) {313 ret = -EBUSY;314 goto err;315 }316 } else {317 phys_addr_t addr = 0;318 319 /*320 * If there is enough memory, try a bottom-up allocation first.321 * It will place the new cma area close to the start of the node322 * and guarantee that the compaction is moving pages out of the323 * cma area and not into it.324 * Avoid using first 4GB to not interfere with constrained zones325 * like DMA/DMA32.326 */327#ifdef CONFIG_PHYS_ADDR_T_64BIT328 if (!memblock_bottom_up() && memblock_end >= SZ_4G + size) {329 memblock_set_bottom_up(true);330 addr = memblock_alloc_range_nid(size, alignment, SZ_4G,331 limit, nid, true);332 memblock_set_bottom_up(false);333 }334#endif335 336 /*337 * All pages in the reserved area must come from the same zone.338 * If the requested region crosses the low/high memory boundary,339 * try allocating from high memory first and fall back to low340 * memory in case of failure.341 */342 if (!addr && base < highmem_start && limit > highmem_start) {343 addr = memblock_alloc_range_nid(size, alignment,344 highmem_start, limit, nid, true);345 limit = highmem_start;346 }347 348 if (!addr) {349 addr = memblock_alloc_range_nid(size, alignment, base,350 limit, nid, true);351 if (!addr) {352 ret = -ENOMEM;353 goto err;354 }355 }356 357 /*358 * kmemleak scans/reads tracked objects for pointers to other359 * objects but this address isn't mapped and accessible360 */361 kmemleak_ignore_phys(addr);362 base = addr;363 }364 365 ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);366 if (ret)367 goto free_mem;368 369 pr_info("Reserved %ld MiB at %pa on node %d\n", (unsigned long)size / SZ_1M,370 &base, nid);371 return 0;372 373free_mem:374 memblock_phys_free(base, size);375err:376 pr_err("Failed to reserve %ld MiB on node %d\n", (unsigned long)size / SZ_1M,377 nid);378 return ret;379}380 381static void cma_debug_show_areas(struct cma *cma)382{383 unsigned long next_zero_bit, next_set_bit, nr_zero;384 unsigned long start = 0;385 unsigned long nr_part, nr_total = 0;386 unsigned long nbits = cma_bitmap_maxno(cma);387 388 spin_lock_irq(&cma->lock);389 pr_info("number of available pages: ");390 for (;;) {391 next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start);392 if (next_zero_bit >= nbits)393 break;394 next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit);395 nr_zero = next_set_bit - next_zero_bit;396 nr_part = nr_zero << cma->order_per_bit;397 pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part,398 next_zero_bit);399 nr_total += nr_part;400 start = next_zero_bit + nr_zero;401 }402 pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count);403 spin_unlock_irq(&cma->lock);404}405 406static struct page *__cma_alloc(struct cma *cma, unsigned long count,407 unsigned int align, gfp_t gfp)408{409 unsigned long mask, offset;410 unsigned long pfn = -1;411 unsigned long start = 0;412 unsigned long bitmap_maxno, bitmap_no, bitmap_count;413 unsigned long i;414 struct page *page = NULL;415 int ret = -ENOMEM;416 const char *name = cma ? cma->name : NULL;417 418 trace_cma_alloc_start(name, count, align);419 420 if (!cma || !cma->count || !cma->bitmap)421 return page;422 423 pr_debug("%s(cma %p, name: %s, count %lu, align %d)\n", __func__,424 (void *)cma, cma->name, count, align);425 426 if (!count)427 return page;428 429 mask = cma_bitmap_aligned_mask(cma, align);430 offset = cma_bitmap_aligned_offset(cma, align);431 bitmap_maxno = cma_bitmap_maxno(cma);432 bitmap_count = cma_bitmap_pages_to_bits(cma, count);433 434 if (bitmap_count > bitmap_maxno)435 return page;436 437 for (;;) {438 spin_lock_irq(&cma->lock);439 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,440 bitmap_maxno, start, bitmap_count, mask,441 offset);442 if (bitmap_no >= bitmap_maxno) {443 spin_unlock_irq(&cma->lock);444 break;445 }446 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);447 /*448 * It's safe to drop the lock here. We've marked this region for449 * our exclusive use. If the migration fails we will take the450 * lock again and unmark it.451 */452 spin_unlock_irq(&cma->lock);453 454 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);455 mutex_lock(&cma_mutex);456 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, gfp);457 mutex_unlock(&cma_mutex);458 if (ret == 0) {459 page = pfn_to_page(pfn);460 break;461 }462 463 cma_clear_bitmap(cma, pfn, count);464 if (ret != -EBUSY)465 break;466 467 pr_debug("%s(): memory range at pfn 0x%lx %p is busy, retrying\n",468 __func__, pfn, pfn_to_page(pfn));469 470 trace_cma_alloc_busy_retry(cma->name, pfn, pfn_to_page(pfn),471 count, align);472 /* try again with a bit different memory target */473 start = bitmap_no + mask + 1;474 }475 476 /*477 * CMA can allocate multiple page blocks, which results in different478 * blocks being marked with different tags. Reset the tags to ignore479 * those page blocks.480 */481 if (page) {482 for (i = 0; i < count; i++)483 page_kasan_tag_reset(nth_page(page, i));484 }485 486 if (ret && !(gfp & __GFP_NOWARN)) {487 pr_err_ratelimited("%s: %s: alloc failed, req-size: %lu pages, ret: %d\n",488 __func__, cma->name, count, ret);489 cma_debug_show_areas(cma);490 }491 492 pr_debug("%s(): returned %p\n", __func__, page);493 trace_cma_alloc_finish(name, pfn, page, count, align, ret);494 if (page) {495 count_vm_event(CMA_ALLOC_SUCCESS);496 cma_sysfs_account_success_pages(cma, count);497 } else {498 count_vm_event(CMA_ALLOC_FAIL);499 cma_sysfs_account_fail_pages(cma, count);500 }501 502 return page;503}504 505/**506 * cma_alloc() - allocate pages from contiguous area507 * @cma: Contiguous memory region for which the allocation is performed.508 * @count: Requested number of pages.509 * @align: Requested alignment of pages (in PAGE_SIZE order).510 * @no_warn: Avoid printing message about failed allocation511 *512 * This function allocates part of contiguous memory on specific513 * contiguous memory area.514 */515struct page *cma_alloc(struct cma *cma, unsigned long count,516 unsigned int align, bool no_warn)517{518 return __cma_alloc(cma, count, align, GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));519}520 521struct folio *cma_alloc_folio(struct cma *cma, int order, gfp_t gfp)522{523 struct page *page;524 525 if (WARN_ON(!order || !(gfp & __GFP_COMP)))526 return NULL;527 528 page = __cma_alloc(cma, 1 << order, order, gfp);529 530 return page ? page_folio(page) : NULL;531}532 533bool cma_pages_valid(struct cma *cma, const struct page *pages,534 unsigned long count)535{536 unsigned long pfn;537 538 if (!cma || !pages)539 return false;540 541 pfn = page_to_pfn(pages);542 543 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) {544 pr_debug("%s(page %p, count %lu)\n", __func__,545 (void *)pages, count);546 return false;547 }548 549 return true;550}551 552/**553 * cma_release() - release allocated pages554 * @cma: Contiguous memory region for which the allocation is performed.555 * @pages: Allocated pages.556 * @count: Number of allocated pages.557 *558 * This function releases memory allocated by cma_alloc().559 * It returns false when provided pages do not belong to contiguous area and560 * true otherwise.561 */562bool cma_release(struct cma *cma, const struct page *pages,563 unsigned long count)564{565 unsigned long pfn;566 567 if (!cma_pages_valid(cma, pages, count))568 return false;569 570 pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count);571 572 pfn = page_to_pfn(pages);573 574 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);575 576 free_contig_range(pfn, count);577 cma_clear_bitmap(cma, pfn, count);578 cma_sysfs_account_release_pages(cma, count);579 trace_cma_release(cma->name, pfn, pages, count);580 581 return true;582}583 584bool cma_free_folio(struct cma *cma, const struct folio *folio)585{586 if (WARN_ON(!folio_test_large(folio)))587 return false;588 589 return cma_release(cma, &folio->page, folio_nr_pages(folio));590}591 592int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)593{594 int i;595 596 for (i = 0; i < cma_area_count; i++) {597 int ret = it(&cma_areas[i], data);598 599 if (ret)600 return ret;601 }602 603 return 0;604}605