mm/cma.c

   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/mutex.h>
  28 #include <linux/sizes.h>
  29 #include <linux/slab.h>
  30 #include <linux/log2.h>
  31 #include <linux/cma.h>
  32 #include <linux/highmem.h>
  33 #include <linux/io.h>
  34 #include <linux/kmemleak.h>
  35 #include <trace/events/cma.h>
  36
  37 #include "cma.h"
  38
  39 struct cma cma_areas[MAX_CMA_AREAS];
  40 unsigned cma_area_count;
  41 static DEFINE_MUTEX(cma_mutex);
  42
  43 phys_addr_t cma_get_base(const struct cma *cma)
  44 {
  45         return PFN_PHYS(cma->base_pfn);
  46 }
  47
  48 unsigned long cma_get_size(const struct cma *cma)
  49 {
  50         return cma->count << PAGE_SHIFT;
  51 }
  52
  53 const char *cma_get_name(const struct cma *cma)
  54 {
  55         return cma->name ? cma->name : "(undefined)";
  56 }
  57
  58 static unsigned long cma_bitmap_aligned_mask(const struct cma *cma,
  59                                              unsigned int align_order)
  60 {
  61         if (align_order <= cma->order_per_bit)
  62                 return 0;
  63         return (1UL << (align_order - cma->order_per_bit)) - 1;
  64 }
  65
  66 /*
  67  * Find the offset of the base PFN from the specified align_order.
  68  * The value returned is represented in order_per_bits.
  69  */
  70 static unsigned long cma_bitmap_aligned_offset(const struct cma *cma,
  71                                                unsigned int align_order)
  72 {
  73         return (cma->base_pfn & ((1UL << align_order) - 1))
  74                 >> cma->order_per_bit;
  75 }
  76
  77 static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma,
  78                                               unsigned long pages)
  79 {
  80         return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit;
  81 }
  82
  83 static void cma_clear_bitmap(struct cma *cma, unsigned long pfn,
  84                              unsigned int count)
  85 {
  86         unsigned long bitmap_no, bitmap_count;
  87
  88         bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit;
  89         bitmap_count = cma_bitmap_pages_to_bits(cma, count);
  90
  91         mutex_lock(&cma->lock);
  92         bitmap_clear(cma->bitmap, bitmap_no, bitmap_count);
  93         mutex_unlock(&cma->lock);
  94 }
  95
  96 static int __init cma_activate_area(struct cma *cma)
  97 {
  98         unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
  99         unsigned i = cma->count >> pageblock_order;
 100         struct zone *zone;
 101
 102         cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL);
 103         if (!cma->bitmap) {
 104                 cma->count = 0;
 105                 return -ENOMEM;
 106         }
 107
 108         WARN_ON_ONCE(!pfn_valid(pfn));
 109         zone = page_zone(pfn_to_page(pfn));
 110
 111         do {
 112                 unsigned j;
 113
 114                 base_pfn = pfn;
 115                 for (j = pageblock_nr_pages; j; --j, pfn++) {
 116                         WARN_ON_ONCE(!pfn_valid(pfn));
 117                         /*
 118                          * alloc_contig_range requires the pfn range
 119                          * specified to be in the same zone. Make this
 120                          * simple by forcing the entire CMA resv range
 121                          * to be in the same zone.
 122                          */
 123                         if (page_zone(pfn_to_page(pfn)) != zone)
 124                                 goto not_in_zone;
 125                 }
 126                 init_cma_reserved_pageblock(pfn_to_page(base_pfn));
 127         } while (--i);
 128
 129         mutex_init(&cma->lock);
 130
 131 #ifdef CONFIG_CMA_DEBUGFS
 132         INIT_HLIST_HEAD(&cma->mem_head);
 133         spin_lock_init(&cma->mem_head_lock);
 134 #endif
 135
 136         return 0;
 137
 138 not_in_zone:
 139         pr_err("CMA area %s could not be activated\n", cma->name);
 140         bitmap_free(cma->bitmap);
 141         cma->count = 0;
 142         return -EINVAL;
 143 }
 144
 145 static int __init cma_init_reserved_areas(void)
 146 {
 147         int i;
 148
 149         for (i = 0; i < cma_area_count; i++) {
 150                 int ret = cma_activate_area(&cma_areas[i]);
 151
 152                 if (ret)
 153                         return ret;
 154         }
 155
 156         return 0;
 157 }
 158 core_initcall(cma_init_reserved_areas);
 159
 160 /**
 161  * cma_init_reserved_mem() - create custom contiguous area from reserved memory
 162  * @base: Base address of the reserved area
 163  * @size: Size of the reserved area (in bytes),
 164  * @order_per_bit: Order of pages represented by one bit on bitmap.
 165  * @name: The name of the area. If this parameter is NULL, the name of
 166  *        the area will be set to "cmaN", where N is a running counter of
 167  *        used areas.
 168  * @res_cma: Pointer to store the created cma region.
 169  *
 170  * This function creates custom contiguous area from already reserved memory.
 171  */
 172 int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size,
 173                                  unsigned int order_per_bit,
 174                                  const char *name,
 175                                  struct cma **res_cma)
 176 {
 177         struct cma *cma;
 178         phys_addr_t alignment;
 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         /* ensure minimal alignment required by mm core */
 190         alignment = PAGE_SIZE <<
 191                         max_t(unsigned long, MAX_ORDER - 1, pageblock_order);
 192
 193         /* alignment should be aligned with order_per_bit */
 194         if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit))
 195                 return -EINVAL;
 196
 197         if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size)
 198                 return -EINVAL;
 199
 200         /*
 201          * Each reserved area must be initialised later, when more kernel
 202          * subsystems (like slab allocator) are available.
 203          */
 204         cma = &cma_areas[cma_area_count];
 205         if (name) {
 206                 cma->name = name;
 207         } else {
 208                 cma->name = kasprintf(GFP_KERNEL, "cma%d\n", cma_area_count);
 209                 if (!cma->name)
 210                         return -ENOMEM;
 211         }
 212         cma->base_pfn = PFN_DOWN(base);
 213         cma->count = size >> PAGE_SHIFT;
 214         cma->order_per_bit = order_per_bit;
 215         *res_cma = cma;
 216         cma_area_count++;
 217         totalcma_pages += (size / PAGE_SIZE);
 218
 219         return 0;
 220 }
 221
 222 /**
 223  * cma_declare_contiguous() - reserve custom contiguous area
 224  * @base: Base address of the reserved area optional, use 0 for any
 225  * @size: Size of the reserved area (in bytes),
 226  * @limit: End address of the reserved memory (optional, 0 for any).
 227  * @alignment: Alignment for the CMA area, should be power of 2 or zero
 228  * @order_per_bit: Order of pages represented by one bit on bitmap.
 229  * @fixed: hint about where to place the reserved area
 230  * @name: The name of the area. See function cma_init_reserved_mem()
 231  * @res_cma: Pointer to store the created cma region.
 232  *
 233  * This function reserves memory from early allocator. It should be
 234  * called by arch specific code once the early allocator (memblock or bootmem)
 235  * has been activated and all other subsystems have already allocated/reserved
 236  * memory. This function allows to create custom reserved areas.
 237  *
 238  * If @fixed is true, reserve contiguous area at exactly @base.  If false,
 239  * reserve in range from @base to @limit.
 240  */
 241 int __init cma_declare_contiguous(phys_addr_t base,
 242                         phys_addr_t size, phys_addr_t limit,
 243                         phys_addr_t alignment, unsigned int order_per_bit,
 244                         bool fixed, const char *name, struct cma **res_cma)
 245 {
 246         phys_addr_t memblock_end = memblock_end_of_DRAM();
 247         phys_addr_t highmem_start;
 248         int ret = 0;
 249
 250         /*
 251          * We can't use __pa(high_memory) directly, since high_memory
 252          * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly)
 253          * complain. Find the boundary by adding one to the last valid
 254          * address.
 255          */
 256         highmem_start = __pa(high_memory - 1) + 1;
 257         pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n",
 258                 __func__, &size, &base, &limit, &alignment);
 259
 260         if (cma_area_count == ARRAY_SIZE(cma_areas)) {
 261                 pr_err("Not enough slots for CMA reserved regions!\n");
 262                 return -ENOSPC;
 263         }
 264
 265         if (!size)
 266                 return -EINVAL;
 267
 268         if (alignment && !is_power_of_2(alignment))
 269                 return -EINVAL;
 270
 271         /*
 272          * Sanitise input arguments.
 273          * Pages both ends in CMA area could be merged into adjacent unmovable
 274          * migratetype page by page allocator's buddy algorithm. In the case,
 275          * you couldn't get a contiguous memory, which is not what we want.
 276          */
 277         alignment = max(alignment,  (phys_addr_t)PAGE_SIZE <<
 278                           max_t(unsigned long, MAX_ORDER - 1, pageblock_order));
 279         if (fixed && base & (alignment - 1)) {
 280                 ret = -EINVAL;
 281                 pr_err("Region at %pa must be aligned to %pa bytes\n",
 282                         &base, &alignment);
 283                 goto err;
 284         }
 285         base = ALIGN(base, alignment);
 286         size = ALIGN(size, alignment);
 287         limit &= ~(alignment - 1);
 288
 289         if (!base)
 290                 fixed = false;
 291
 292         /* size should be aligned with order_per_bit */
 293         if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit))
 294                 return -EINVAL;
 295
 296         /*
 297          * If allocating at a fixed base the request region must not cross the
 298          * low/high memory boundary.
 299          */
 300         if (fixed && base < highmem_start && base + size > highmem_start) {
 301                 ret = -EINVAL;
 302                 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n",
 303                         &base, &highmem_start);
 304                 goto err;
 305         }
 306
 307         /*
 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
 310          * checks.
 311          */
 312         if (limit == 0 || limit > memblock_end)
 313                 limit = memblock_end;
 314
 315         if (base + size > limit) {
 316                 ret = -EINVAL;
 317                 pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n",
 318                         &size, &base, &limit);
 319                 goto err;
 320         }
 321
 322         /* Reserve memory */
 323         if (fixed) {
 324                 if (memblock_is_region_reserved(base, size) ||
 325                     memblock_reserve(base, size) < 0) {
 326                         ret = -EBUSY;
 327                         goto err;
 328                 }
 329         } else {
 330                 phys_addr_t addr = 0;
 331
 332                 /*
 333                  * All pages in the reserved area must come from the same zone.
 334                  * If the requested region crosses the low/high memory boundary,
 335                  * try allocating from high memory first and fall back to low
 336                  * memory in case of failure.
 337                  */
 338                 if (base < highmem_start && limit > highmem_start) {
 339                         addr = memblock_phys_alloc_range(size, alignment,
 340                                                          highmem_start, limit);
 341                         limit = highmem_start;
 342                 }
 343
 344                 if (!addr) {
 345                         addr = memblock_phys_alloc_range(size, alignment, base,
 346                                                          limit);
 347                         if (!addr) {
 348                                 ret = -ENOMEM;
 349                                 goto err;
 350                         }
 351                 }
 352
 353                 /*
 354                  * kmemleak scans/reads tracked objects for pointers to other
 355                  * objects but this address isn't mapped and accessible
 356                  */
 357                 kmemleak_ignore_phys(addr);
 358                 base = addr;
 359         }
 360
 361         ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
 362         if (ret)
 363                 goto free_mem;
 364
 365         pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
 366                 &base);
 367         return 0;
 368
 369 free_mem:
 370         memblock_free(base, size);
 371 err:
 372         pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
 373         return ret;
 374 }
 375
 376 #ifdef CONFIG_CMA_DEBUG
 377 static void cma_debug_show_areas(struct cma *cma)
 378 {
 379         unsigned long next_zero_bit, next_set_bit, nr_zero;
 380         unsigned long start = 0;
 381         unsigned long nr_part, nr_total = 0;
 382         unsigned long nbits = cma_bitmap_maxno(cma);
 383
 384         mutex_lock(&cma->lock);
 385         pr_info("number of available pages: ");
 386         for (;;) {
 387                 next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start);
 388                 if (next_zero_bit >= nbits)
 389                         break;
 390                 next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit);
 391                 nr_zero = next_set_bit - next_zero_bit;
 392                 nr_part = nr_zero << cma->order_per_bit;
 393                 pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part,
 394                         next_zero_bit);
 395                 nr_total += nr_part;
 396                 start = next_zero_bit + nr_zero;
 397         }
 398         pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count);
 399         mutex_unlock(&cma->lock);
 400 }
 401 #else
 402 static inline void cma_debug_show_areas(struct cma *cma) { }
 403 #endif
 404
 405 /**
 406  * cma_alloc() - allocate pages from contiguous area
 407  * @cma:   Contiguous memory region for which the allocation is performed.
 408  * @count: Requested number of pages.
 409  * @align: Requested alignment of pages (in PAGE_SIZE order).
 410  * @no_warn: Avoid printing message about failed allocation
 411  *
 412  * This function allocates part of contiguous memory on specific
 413  * contiguous memory area.
 414  */
 415 struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
 416                        bool no_warn)
 417 {
 418         unsigned long mask, offset;
 419         unsigned long pfn = -1;
 420         unsigned long start = 0;
 421         unsigned long bitmap_maxno, bitmap_no, bitmap_count;
 422         size_t i;
 423         struct page *page = NULL;
 424         int ret = -ENOMEM;
 425
 426         if (!cma || !cma->count)
 427                 return NULL;
 428
 429         pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma,
 430                  count, align);
 431
 432         if (!count)
 433                 return NULL;
 434
 435         mask = cma_bitmap_aligned_mask(cma, align);
 436         offset = cma_bitmap_aligned_offset(cma, align);
 437         bitmap_maxno = cma_bitmap_maxno(cma);
 438         bitmap_count = cma_bitmap_pages_to_bits(cma, count);
 439
 440         if (bitmap_count > bitmap_maxno)
 441                 return NULL;
 442
 443         for (;;) {
 444                 mutex_lock(&cma->lock);
 445                 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap,
 446                                 bitmap_maxno, start, bitmap_count, mask,
 447                                 offset);
 448                 if (bitmap_no >= bitmap_maxno) {
 449                         mutex_unlock(&cma->lock);
 450                         break;
 451                 }
 452                 bitmap_set(cma->bitmap, bitmap_no, bitmap_count);
 453                 /*
 454                  * It's safe to drop the lock here. We've marked this region for
 455                  * our exclusive use. If the migration fails we will take the
 456                  * lock again and unmark it.
 457                  */
 458                 mutex_unlock(&cma->lock);
 459
 460                 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
 461                 mutex_lock(&cma_mutex);
 462                 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
 463                                      GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0));
 464                 mutex_unlock(&cma_mutex);
 465                 if (ret == 0) {
 466                         page = pfn_to_page(pfn);
 467                         break;
 468                 }
 469
 470                 cma_clear_bitmap(cma, pfn, count);
 471                 if (ret != -EBUSY)
 472                         break;
 473
 474                 pr_debug("%s(): memory range at %p is busy, retrying\n",
 475                          __func__, pfn_to_page(pfn));
 476                 /* try again with a bit different memory target */
 477                 start = bitmap_no + mask + 1;
 478         }
 479
 480         trace_cma_alloc(pfn, page, count, align);
 481
 482         /*
 483          * CMA can allocate multiple page blocks, which results in different
 484          * blocks being marked with different tags. Reset the tags to ignore
 485          * those page blocks.
 486          */
 487         if (page) {
 488                 for (i = 0; i < count; i++)
 489                         page_kasan_tag_reset(page + i);
 490         }
 491
 492         if (ret && !no_warn) {
 493                 pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n",
 494                         __func__, count, ret);
 495                 cma_debug_show_areas(cma);
 496         }
 497
 498         pr_debug("%s(): returned %p\n", __func__, page);
 499         return page;
 500 }
 501
 502 /**
 503  * cma_release() - release allocated pages
 504  * @cma:   Contiguous memory region for which the allocation is performed.
 505  * @pages: Allocated pages.
 506  * @count: Number of allocated pages.
 507  *
 508  * This function releases memory allocated by cma_alloc().
 509  * It returns false when provided pages do not belong to contiguous area and
 510  * true otherwise.
 511  */
 512 bool cma_release(struct cma *cma, const struct page *pages, unsigned int count)
 513 {
 514         unsigned long pfn;
 515
 516         if (!cma || !pages)
 517                 return false;
 518
 519         pr_debug("%s(page %p)\n", __func__, (void *)pages);
 520
 521         pfn = page_to_pfn(pages);
 522
 523         if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
 524                 return false;
 525
 526         VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
 527
 528         free_contig_range(pfn, count);
 529         cma_clear_bitmap(cma, pfn, count);
 530         trace_cma_release(pfn, pages, count);
 531
 532         return true;
 533 }
 534
 535 int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data)
 536 {
 537         int i;
 538
 539         for (i = 0; i < cma_area_count; i++) {
 540                 int ret = it(&cma_areas[i], data);
 541
 542                 if (ret)
 543                         return ret;
 544         }
 545
 546         return 0;
 547 }