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; 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 void __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 goto out_error; 105 106 WARN_ON_ONCE(!pfn_valid(pfn)); 107 zone = page_zone(pfn_to_page(pfn)); 108 109 do { 110 unsigned j; 111 112 base_pfn = pfn; 113 for (j = pageblock_nr_pages; j; --j, pfn++) { 114 WARN_ON_ONCE(!pfn_valid(pfn)); 115 /* 116 * alloc_contig_range requires the pfn range 117 * specified to be in the same zone. Make this 118 * simple by forcing the entire CMA resv range 119 * to be in the same zone. 120 */ 121 if (page_zone(pfn_to_page(pfn)) != zone) 122 goto not_in_zone; 123 } 124 init_cma_reserved_pageblock(pfn_to_page(base_pfn)); 125 } while (--i); 126 127 mutex_init(&cma->lock); 128 129 #ifdef CONFIG_CMA_DEBUGFS 130 INIT_HLIST_HEAD(&cma->mem_head); 131 spin_lock_init(&cma->mem_head_lock); 132 #endif 133 134 return; 135 136 not_in_zone: 137 bitmap_free(cma->bitmap); 138 out_error: 139 cma->count = 0; 140 pr_err("CMA area %s could not be activated\n", cma->name); 141 return; 142 } 143 144 static int __init cma_init_reserved_areas(void) 145 { 146 int i; 147 148 for (i = 0; i < cma_area_count; i++) 149 cma_activate_area(&cma_areas[i]); 150 151 return 0; 152 } 153 core_initcall(cma_init_reserved_areas); 154 155 /** 156 * cma_init_reserved_mem() - create custom contiguous area from reserved memory 157 * @base: Base address of the reserved area 158 * @size: Size of the reserved area (in bytes), 159 * @order_per_bit: Order of pages represented by one bit on bitmap. 160 * @name: The name of the area. If this parameter is NULL, the name of 161 * the area will be set to "cmaN", where N is a running counter of 162 * used areas. 163 * @res_cma: Pointer to store the created cma region. 164 * 165 * This function creates custom contiguous area from already reserved memory. 166 */ 167 int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, 168 unsigned int order_per_bit, 169 const char *name, 170 struct cma **res_cma) 171 { 172 struct cma *cma; 173 phys_addr_t alignment; 174 175 /* Sanity checks */ 176 if (cma_area_count == ARRAY_SIZE(cma_areas)) { 177 pr_err("Not enough slots for CMA reserved regions!\n"); 178 return -ENOSPC; 179 } 180 181 if (!size || !memblock_is_region_reserved(base, size)) 182 return -EINVAL; 183 184 /* ensure minimal alignment required by mm core */ 185 alignment = PAGE_SIZE << 186 max_t(unsigned long, MAX_ORDER - 1, pageblock_order); 187 188 /* alignment should be aligned with order_per_bit */ 189 if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit)) 190 return -EINVAL; 191 192 if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size) 193 return -EINVAL; 194 195 /* 196 * Each reserved area must be initialised later, when more kernel 197 * subsystems (like slab allocator) are available. 198 */ 199 cma = &cma_areas[cma_area_count]; 200 201 if (name) 202 snprintf(cma->name, CMA_MAX_NAME, name); 203 else 204 snprintf(cma->name, CMA_MAX_NAME, "cma%d\n", cma_area_count); 205 206 cma->base_pfn = PFN_DOWN(base); 207 cma->count = size >> PAGE_SHIFT; 208 cma->order_per_bit = order_per_bit; 209 *res_cma = cma; 210 cma_area_count++; 211 totalcma_pages += (size / PAGE_SIZE); 212 213 return 0; 214 } 215 216 /** 217 * cma_declare_contiguous_nid() - reserve custom contiguous area 218 * @base: Base address of the reserved area optional, use 0 for any 219 * @size: Size of the reserved area (in bytes), 220 * @limit: End address of the reserved memory (optional, 0 for any). 221 * @alignment: Alignment for the CMA area, should be power of 2 or zero 222 * @order_per_bit: Order of pages represented by one bit on bitmap. 223 * @fixed: hint about where to place the reserved area 224 * @name: The name of the area. See function cma_init_reserved_mem() 225 * @res_cma: Pointer to store the created cma region. 226 * @nid: nid of the free area to find, %NUMA_NO_NODE for any node 227 * 228 * This function reserves memory from early allocator. It should be 229 * called by arch specific code once the early allocator (memblock or bootmem) 230 * has been activated and all other subsystems have already allocated/reserved 231 * memory. This function allows to create custom reserved areas. 232 * 233 * If @fixed is true, reserve contiguous area at exactly @base. If false, 234 * reserve in range from @base to @limit. 235 */ 236 int __init cma_declare_contiguous_nid(phys_addr_t base, 237 phys_addr_t size, phys_addr_t limit, 238 phys_addr_t alignment, unsigned int order_per_bit, 239 bool fixed, const char *name, struct cma **res_cma, 240 int nid) 241 { 242 phys_addr_t memblock_end = memblock_end_of_DRAM(); 243 phys_addr_t highmem_start; 244 int ret = 0; 245 246 /* 247 * We can't use __pa(high_memory) directly, since high_memory 248 * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly) 249 * complain. Find the boundary by adding one to the last valid 250 * address. 251 */ 252 highmem_start = __pa(high_memory - 1) + 1; 253 pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n", 254 __func__, &size, &base, &limit, &alignment); 255 256 if (cma_area_count == ARRAY_SIZE(cma_areas)) { 257 pr_err("Not enough slots for CMA reserved regions!\n"); 258 return -ENOSPC; 259 } 260 261 if (!size) 262 return -EINVAL; 263 264 if (alignment && !is_power_of_2(alignment)) 265 return -EINVAL; 266 267 /* 268 * Sanitise input arguments. 269 * Pages both ends in CMA area could be merged into adjacent unmovable 270 * migratetype page by page allocator's buddy algorithm. In the case, 271 * you couldn't get a contiguous memory, which is not what we want. 272 */ 273 alignment = max(alignment, (phys_addr_t)PAGE_SIZE << 274 max_t(unsigned long, MAX_ORDER - 1, pageblock_order)); 275 if (fixed && base & (alignment - 1)) { 276 ret = -EINVAL; 277 pr_err("Region at %pa must be aligned to %pa bytes\n", 278 &base, &alignment); 279 goto err; 280 } 281 base = ALIGN(base, alignment); 282 size = ALIGN(size, alignment); 283 limit &= ~(alignment - 1); 284 285 if (!base) 286 fixed = false; 287 288 /* size should be aligned with order_per_bit */ 289 if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit)) 290 return -EINVAL; 291 292 /* 293 * If allocating at a fixed base the request region must not cross the 294 * low/high memory boundary. 295 */ 296 if (fixed && base < highmem_start && base + size > highmem_start) { 297 ret = -EINVAL; 298 pr_err("Region at %pa defined on low/high memory boundary (%pa)\n", 299 &base, &highmem_start); 300 goto err; 301 } 302 303 /* 304 * If the limit is unspecified or above the memblock end, its effective 305 * value will be the memblock end. Set it explicitly to simplify further 306 * checks. 307 */ 308 if (limit == 0 || limit > memblock_end) 309 limit = memblock_end; 310 311 if (base + size > limit) { 312 ret = -EINVAL; 313 pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n", 314 &size, &base, &limit); 315 goto err; 316 } 317 318 /* Reserve memory */ 319 if (fixed) { 320 if (memblock_is_region_reserved(base, size) || 321 memblock_reserve(base, size) < 0) { 322 ret = -EBUSY; 323 goto err; 324 } 325 } else { 326 phys_addr_t addr = 0; 327 328 /* 329 * All pages in the reserved area must come from the same zone. 330 * If the requested region crosses the low/high memory boundary, 331 * try allocating from high memory first and fall back to low 332 * memory in case of failure. 333 */ 334 if (base < highmem_start && limit > highmem_start) { 335 addr = memblock_alloc_range_nid(size, alignment, 336 highmem_start, limit, nid, true); 337 limit = highmem_start; 338 } 339 340 if (!addr) { 341 addr = memblock_alloc_range_nid(size, alignment, base, 342 limit, nid, true); 343 if (!addr) { 344 ret = -ENOMEM; 345 goto err; 346 } 347 } 348 349 /* 350 * kmemleak scans/reads tracked objects for pointers to other 351 * objects but this address isn't mapped and accessible 352 */ 353 kmemleak_ignore_phys(addr); 354 base = addr; 355 } 356 357 ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma); 358 if (ret) 359 goto free_mem; 360 361 pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M, 362 &base); 363 return 0; 364 365 free_mem: 366 memblock_free(base, size); 367 err: 368 pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M); 369 return ret; 370 } 371 372 #ifdef CONFIG_CMA_DEBUG 373 static void cma_debug_show_areas(struct cma *cma) 374 { 375 unsigned long next_zero_bit, next_set_bit, nr_zero; 376 unsigned long start = 0; 377 unsigned long nr_part, nr_total = 0; 378 unsigned long nbits = cma_bitmap_maxno(cma); 379 380 mutex_lock(&cma->lock); 381 pr_info("number of available pages: "); 382 for (;;) { 383 next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start); 384 if (next_zero_bit >= nbits) 385 break; 386 next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit); 387 nr_zero = next_set_bit - next_zero_bit; 388 nr_part = nr_zero << cma->order_per_bit; 389 pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part, 390 next_zero_bit); 391 nr_total += nr_part; 392 start = next_zero_bit + nr_zero; 393 } 394 pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count); 395 mutex_unlock(&cma->lock); 396 } 397 #else 398 static inline void cma_debug_show_areas(struct cma *cma) { } 399 #endif 400 401 /** 402 * cma_alloc() - allocate pages from contiguous area 403 * @cma: Contiguous memory region for which the allocation is performed. 404 * @count: Requested number of pages. 405 * @align: Requested alignment of pages (in PAGE_SIZE order). 406 * @no_warn: Avoid printing message about failed allocation 407 * 408 * This function allocates part of contiguous memory on specific 409 * contiguous memory area. 410 */ 411 struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align, 412 bool no_warn) 413 { 414 unsigned long mask, offset; 415 unsigned long pfn = -1; 416 unsigned long start = 0; 417 unsigned long bitmap_maxno, bitmap_no, bitmap_count; 418 size_t i; 419 struct page *page = NULL; 420 int ret = -ENOMEM; 421 422 if (!cma || !cma->count || !cma->bitmap) 423 return NULL; 424 425 pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma, 426 count, align); 427 428 if (!count) 429 return NULL; 430 431 mask = cma_bitmap_aligned_mask(cma, align); 432 offset = cma_bitmap_aligned_offset(cma, align); 433 bitmap_maxno = cma_bitmap_maxno(cma); 434 bitmap_count = cma_bitmap_pages_to_bits(cma, count); 435 436 if (bitmap_count > bitmap_maxno) 437 return NULL; 438 439 for (;;) { 440 mutex_lock(&cma->lock); 441 bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, 442 bitmap_maxno, start, bitmap_count, mask, 443 offset); 444 if (bitmap_no >= bitmap_maxno) { 445 mutex_unlock(&cma->lock); 446 break; 447 } 448 bitmap_set(cma->bitmap, bitmap_no, bitmap_count); 449 /* 450 * It's safe to drop the lock here. We've marked this region for 451 * our exclusive use. If the migration fails we will take the 452 * lock again and unmark it. 453 */ 454 mutex_unlock(&cma->lock); 455 456 pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); 457 mutex_lock(&cma_mutex); 458 ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, 459 GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); 460 mutex_unlock(&cma_mutex); 461 if (ret == 0) { 462 page = pfn_to_page(pfn); 463 break; 464 } 465 466 cma_clear_bitmap(cma, pfn, count); 467 if (ret != -EBUSY) 468 break; 469 470 pr_debug("%s(): memory range at %p is busy, retrying\n", 471 __func__, pfn_to_page(pfn)); 472 /* try again with a bit different memory target */ 473 start = bitmap_no + mask + 1; 474 } 475 476 trace_cma_alloc(pfn, page, count, align); 477 478 /* 479 * CMA can allocate multiple page blocks, which results in different 480 * blocks being marked with different tags. Reset the tags to ignore 481 * those page blocks. 482 */ 483 if (page) { 484 for (i = 0; i < count; i++) 485 page_kasan_tag_reset(page + i); 486 } 487 488 if (ret && !no_warn) { 489 pr_err("%s: alloc failed, req-size: %zu pages, ret: %d\n", 490 __func__, count, ret); 491 cma_debug_show_areas(cma); 492 } 493 494 pr_debug("%s(): returned %p\n", __func__, page); 495 return page; 496 } 497 498 /** 499 * cma_release() - release allocated pages 500 * @cma: Contiguous memory region for which the allocation is performed. 501 * @pages: Allocated pages. 502 * @count: Number of allocated pages. 503 * 504 * This function releases memory allocated by cma_alloc(). 505 * It returns false when provided pages do not belong to contiguous area and 506 * true otherwise. 507 */ 508 bool cma_release(struct cma *cma, const struct page *pages, unsigned int count) 509 { 510 unsigned long pfn; 511 512 if (!cma || !pages) 513 return false; 514 515 pr_debug("%s(page %p)\n", __func__, (void *)pages); 516 517 pfn = page_to_pfn(pages); 518 519 if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) 520 return false; 521 522 VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); 523 524 free_contig_range(pfn, count); 525 cma_clear_bitmap(cma, pfn, count); 526 trace_cma_release(pfn, pages, count); 527 528 return true; 529 } 530 531 int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data) 532 { 533 int i; 534 535 for (i = 0; i < cma_area_count; i++) { 536 int ret = it(&cma_areas[i], data); 537 538 if (ret) 539 return ret; 540 } 541 542 return 0; 543 } 544