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_nid() - 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 * @nid: nid of the free area to find, %NUMA_NO_NODE for any node 233 * 234 * This function reserves memory from early allocator. It should be 235 * called by arch specific code once the early allocator (memblock or bootmem) 236 * has been activated and all other subsystems have already allocated/reserved 237 * memory. This function allows to create custom reserved areas. 238 * 239 * If @fixed is true, reserve contiguous area at exactly @base. If false, 240 * reserve in range from @base to @limit. 241 */ 242 int __init cma_declare_contiguous_nid(phys_addr_t base, 243 phys_addr_t size, phys_addr_t limit, 244 phys_addr_t alignment, unsigned int order_per_bit, 245 bool fixed, const char *name, struct cma **res_cma, 246 int nid) 247 { 248 phys_addr_t memblock_end = memblock_end_of_DRAM(); 249 phys_addr_t highmem_start; 250 int ret = 0; 251 252 /* 253 * We can't use __pa(high_memory) directly, since high_memory 254 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly) 255 * complain. Find the boundary by adding one to the last valid 256 * address. 257 */ 258 highmem_start = __pa(high_memory - 1) + 1; 259 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n", 260 __func__, &size, &base, &limit, &alignment); 261 262 if (cma_area_count == ARRAY_SIZE(cma_areas)) { 263 pr_err("Not enough slots for CMA reserved regions!\n"); 264 return -ENOSPC; 265 } 266 267 if (!size) 268 return -EINVAL; 269 270 if (alignment && !is_power_of_2(alignment)) 271 return -EINVAL; 272 273 /* 274 * Sanitise input arguments. 275 * Pages both ends in CMA area could be merged into adjacent unmovable 276 * migratetype page by page allocator's buddy algorithm. In the case, 277 * you couldn't get a contiguous memory, which is not what we want. 278 */ 279 alignment = max(alignment, (phys_addr_t)PAGE_SIZE << 280 max_t(unsigned long, MAX_ORDER - 1, pageblock_order)); 281 if (fixed && base & (alignment - 1)) { 282 ret = -EINVAL; 283 pr_err("Region at %pa must be aligned to %pa bytes\n", 284 &base, &alignment); 285 goto err; 286 } 287 base = ALIGN(base, alignment); 288 size = ALIGN(size, alignment); 289 limit &= ~(alignment - 1); 290 291 if (!base) 292 fixed = false; 293 294 /* size should be aligned with order_per_bit */ 295 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit)) 296 return -EINVAL; 297 298 /* 299 * If allocating at a fixed base the request region must not cross the 300 * low/high memory boundary. 301 */ 302 if (fixed && base < highmem_start && base + size > highmem_start) { 303 ret = -EINVAL; 304 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n", 305 &base, &highmem_start); 306 goto err; 307 } 308 309 /* 310 * If the limit is unspecified or above the memblock end, its effective 311 * value will be the memblock end. Set it explicitly to simplify further 312 * checks. 313 */ 314 if (limit == 0 || limit > memblock_end) 315 limit = memblock_end; 316 317 if (base + size > limit) { 318 ret = -EINVAL; 319 pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n", 320 &size, &base, &limit); 321 goto err; 322 } 323 324 /* Reserve memory */ 325 if (fixed) { 326 if (memblock_is_region_reserved(base, size) || 327 memblock_reserve(base, size) < 0) { 328 ret = -EBUSY; 329 goto err; 330 } 331 } else { 332 phys_addr_t addr = 0; 333 334 /* 335 * All pages in the reserved area must come from the same zone. 336 * If the requested region crosses the low/high memory boundary, 337 * try allocating from high memory first and fall back to low 338 * memory in case of failure. 339 */ 340 if (base < highmem_start && limit > highmem_start) { 341 addr = memblock_alloc_range_nid(size, alignment, 342 highmem_start, limit, nid, true); 343 limit = highmem_start; 344 } 345 346 if (!addr) { 347 addr = memblock_alloc_range_nid(size, alignment, base, 348 limit, nid, true); 349 if (!addr) { 350 ret = -ENOMEM; 351 goto err; 352 } 353 } 354 355 /* 356 * kmemleak scans/reads tracked objects for pointers to other 357 * objects but this address isn't mapped and accessible 358 */ 359 kmemleak_ignore_phys(addr); 360 base = addr; 361 } 362 363 ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma); 364 if (ret) 365 goto free_mem; 366 367 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M, 368 &base); 369 return 0; 370 371 free_mem: 372 memblock_free(base, size); 373 err: 374 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M); 375 return ret; 376 } 377 378 #ifdef CONFIG_CMA_DEBUG 379 static void cma_debug_show_areas(struct cma *cma) 380 { 381 unsigned long next_zero_bit, next_set_bit, nr_zero; 382 unsigned long start = 0; 383 unsigned long nr_part, nr_total = 0; 384 unsigned long nbits = cma_bitmap_maxno(cma); 385 386 mutex_lock(&cma->lock); 387 pr_info("number of available pages: "); 388 for (;;) { 389 next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start); 390 if (next_zero_bit >= nbits) 391 break; 392 next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit); 393 nr_zero = next_set_bit - next_zero_bit; 394 nr_part = nr_zero << cma->order_per_bit; 395 pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part, 396 next_zero_bit); 397 nr_total += nr_part; 398 start = next_zero_bit + nr_zero; 399 } 400 pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count); 401 mutex_unlock(&cma->lock); 402 } 403 #else 404 static inline void cma_debug_show_areas(struct cma *cma) { } 405 #endif 406 407 /** 408 * cma_alloc() - allocate pages from contiguous area 409 * @cma: Contiguous memory region for which the allocation is performed. 410 * @count: Requested number of pages. 411 * @align: Requested alignment of pages (in PAGE_SIZE order). 412 * @no_warn: Avoid printing message about failed allocation 413 * 414 * This function allocates part of contiguous memory on specific 415 * contiguous memory area. 416 */ 417 struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, 418 bool no_warn) 419 { 420 unsigned long mask, offset; 421 unsigned long pfn = -1; 422 unsigned long start = 0; 423 unsigned long bitmap_maxno, bitmap_no, bitmap_count; 424 size_t i; 425 struct page *page = NULL; 426 int ret = -ENOMEM; 427 428 if (!cma || !cma->count) 429 return NULL; 430 431 pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma, 432 count, align); 433 434 if (!count) 435 return NULL; 436 437 mask = cma_bitmap_aligned_mask(cma, align); 438 offset = cma_bitmap_aligned_offset(cma, align); 439 bitmap_maxno = cma_bitmap_maxno(cma); 440 bitmap_count = cma_bitmap_pages_to_bits(cma, count); 441 442 if (bitmap_count > bitmap_maxno) 443 return NULL; 444 445 for (;;) { 446 mutex_lock(&cma->lock); 447 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, 448 bitmap_maxno, start, bitmap_count, mask, 449 offset); 450 if (bitmap_no >= bitmap_maxno) { 451 mutex_unlock(&cma->lock); 452 break; 453 } 454 bitmap_set(cma->bitmap, bitmap_no, bitmap_count); 455 /* 456 * It's safe to drop the lock here. We've marked this region for 457 * our exclusive use. If the migration fails we will take the 458 * lock again and unmark it. 459 */ 460 mutex_unlock(&cma->lock); 461 462 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); 463 mutex_lock(&cma_mutex); 464 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, 465 GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); 466 mutex_unlock(&cma_mutex); 467 if (ret == 0) { 468 page = pfn_to_page(pfn); 469 break; 470 } 471 472 cma_clear_bitmap(cma, pfn, count); 473 if (ret != -EBUSY) 474 break; 475 476 pr_debug("%s(): memory range at %p is busy, retrying\n", 477 __func__, pfn_to_page(pfn)); 478 /* try again with a bit different memory target */ 479 start = bitmap_no + mask + 1; 480 } 481 482 trace_cma_alloc(pfn, page, count, align); 483 484 /* 485 * CMA can allocate multiple page blocks, which results in different 486 * blocks being marked with different tags. Reset the tags to ignore 487 * those page blocks. 488 */ 489 if (page) { 490 for (i = 0; i < count; i++) 491 page_kasan_tag_reset(page + i); 492 } 493 494 if (ret && !no_warn) { 495 pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n", 496 __func__, count, ret); 497 cma_debug_show_areas(cma); 498 } 499 500 pr_debug("%s(): returned %p\n", __func__, page); 501 return page; 502 } 503 504 /** 505 * cma_release() - release allocated pages 506 * @cma: Contiguous memory region for which the allocation is performed. 507 * @pages: Allocated pages. 508 * @count: Number of allocated pages. 509 * 510 * This function releases memory allocated by cma_alloc(). 511 * It returns false when provided pages do not belong to contiguous area and 512 * true otherwise. 513 */ 514 bool cma_release(struct cma *cma, const struct page *pages, unsigned int count) 515 { 516 unsigned long pfn; 517 518 if (!cma || !pages) 519 return false; 520 521 pr_debug("%s(page %p)\n", __func__, (void *)pages); 522 523 pfn = page_to_pfn(pages); 524 525 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) 526 return false; 527 528 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); 529 530 free_contig_range(pfn, count); 531 cma_clear_bitmap(cma, pfn, count); 532 trace_cma_release(pfn, pages, count); 533 534 return true; 535 } 536 537 int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data) 538 { 539 int i; 540 541 for (i = 0; i < cma_area_count; i++) { 542 int ret = it(&cma_areas[i], data); 543 544 if (ret) 545 return ret; 546 } 547 548 return 0; 549 } 550