// SPDX-License-Identifier: GPL-2.0-or-later /* * Contiguous Memory Allocator * * Copyright (c) 2010-2011 by Samsung Electronics. * Copyright IBM Corporation, 2013 * Copyright LG Electronics Inc., 2014 * Written by: * Marek Szyprowski <m.szyprowski@samsung.com> * Michal Nazarewicz <mina86@mina86.com> * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> * Joonsoo Kim <iamjoonsoo.kim@lge.com> */ #define pr_fmt(fmt) "cma: " fmt #define CREATE_TRACE_POINTS #include <linux/memblock.h> #include <linux/err.h> #include <linux/mm.h> #include <linux/sizes.h> #include <linux/slab.h> #include <linux/log2.h> #include <linux/cma.h> #include <linux/highmem.h> #include <linux/io.h> #include <linux/kmemleak.h> #include <trace/events/cma.h> #include "internal.h" #include "cma.h" struct cma cma_areas[MAX_CMA_AREAS]; unsigned cma_area_count; static DEFINE_MUTEX(cma_mutex); phys_addr_t cma_get_base(const struct cma *cma) { return PFN_PHYS(cma->base_pfn); } unsigned long cma_get_size(const struct cma *cma) { return cma->count << PAGE_SHIFT; } const char *cma_get_name(const struct cma *cma) { return cma->name; } static unsigned long cma_bitmap_aligned_mask(const struct cma *cma, unsigned int align_order) { if (align_order <= cma->order_per_bit) return 0; return (1UL << (align_order - cma->order_per_bit)) - 1; } /* * Find the offset of the base PFN from the specified align_order. * The value returned is represented in order_per_bits. */ static unsigned long cma_bitmap_aligned_offset(const struct cma *cma, unsigned int align_order) { return (cma->base_pfn & ((1UL << align_order) - 1)) >> cma->order_per_bit; } static unsigned long cma_bitmap_pages_to_bits(const struct cma *cma, unsigned long pages) { return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit; } static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, unsigned long count) { unsigned long bitmap_no, bitmap_count; unsigned long flags; bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit; bitmap_count = cma_bitmap_pages_to_bits(cma, count); spin_lock_irqsave(&cma->lock, flags); bitmap_clear(cma->bitmap, bitmap_no, bitmap_count); spin_unlock_irqrestore(&cma->lock, flags); } static void __init cma_activate_area(struct cma *cma) { unsigned long base_pfn = cma->base_pfn, pfn; struct zone *zone; cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL); if (!cma->bitmap) goto out_error; /* * alloc_contig_range() requires the pfn range specified to be in the * same zone. Simplify by forcing the entire CMA resv range to be in the * same zone. */ WARN_ON_ONCE(!pfn_valid(base_pfn)); zone = page_zone(pfn_to_page(base_pfn)); for (pfn = base_pfn + 1; pfn < base_pfn + cma->count; pfn++) { WARN_ON_ONCE(!pfn_valid(pfn)); if (page_zone(pfn_to_page(pfn)) != zone) goto not_in_zone; } for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn += pageblock_nr_pages) init_cma_reserved_pageblock(pfn_to_page(pfn)); spin_lock_init(&cma->lock); #ifdef CONFIG_CMA_DEBUGFS INIT_HLIST_HEAD(&cma->mem_head); spin_lock_init(&cma->mem_head_lock); #endif return; not_in_zone: bitmap_free(cma->bitmap); out_error: /* Expose all pages to the buddy, they are useless for CMA. */ if (!cma->reserve_pages_on_error) { for (pfn = base_pfn; pfn < base_pfn + cma->count; pfn++) free_reserved_page(pfn_to_page(pfn)); } totalcma_pages -= cma->count; cma->count = 0; pr_err("CMA area %s could not be activated\n", cma->name); return; } static int __init cma_init_reserved_areas(void) { int i; for (i = 0; i < cma_area_count; i++) cma_activate_area(&cma_areas[i]); return 0; } core_initcall(cma_init_reserved_areas); void __init cma_reserve_pages_on_error(struct cma *cma) { cma->reserve_pages_on_error = true; } /** * cma_init_reserved_mem() - create custom contiguous area from reserved memory * @base: Base address of the reserved area * @size: Size of the reserved area (in bytes), * @order_per_bit: Order of pages represented by one bit on bitmap. * @name: The name of the area. If this parameter is NULL, the name of * the area will be set to "cmaN", where N is a running counter of * used areas. * @res_cma: Pointer to store the created cma region. * * This function creates custom contiguous area from already reserved memory. */ int __init cma_init_reserved_mem(phys_addr_t base, phys_addr_t size, unsigned int order_per_bit, const char *name, struct cma **res_cma) { struct cma *cma; /* Sanity checks */ if (cma_area_count == ARRAY_SIZE(cma_areas)) { pr_err("Not enough slots for CMA reserved regions!\n"); return -ENOSPC; } if (!size || !memblock_is_region_reserved(base, size)) return -EINVAL; /* ensure minimal alignment required by mm core */ if (!IS_ALIGNED(base | size, CMA_MIN_ALIGNMENT_BYTES)) return -EINVAL; /* * Each reserved area must be initialised later, when more kernel * subsystems (like slab allocator) are available. */ cma = &cma_areas[cma_area_count]; if (name) snprintf(cma->name, CMA_MAX_NAME, name); else snprintf(cma->name, CMA_MAX_NAME, "cma%d\n", cma_area_count); cma->base_pfn = PFN_DOWN(base); cma->count = size >> PAGE_SHIFT; cma->order_per_bit = order_per_bit; *res_cma = cma; cma_area_count++; totalcma_pages += (size / PAGE_SIZE); return 0; } /** * cma_declare_contiguous_nid() - reserve custom contiguous area * @base: Base address of the reserved area optional, use 0 for any * @size: Size of the reserved area (in bytes), * @limit: End address of the reserved memory (optional, 0 for any). * @alignment: Alignment for the CMA area, should be power of 2 or zero * @order_per_bit: Order of pages represented by one bit on bitmap. * @fixed: hint about where to place the reserved area * @name: The name of the area. See function cma_init_reserved_mem() * @res_cma: Pointer to store the created cma region. * @nid: nid of the free area to find, %NUMA_NO_NODE for any node * * This function reserves memory from early allocator. It should be * called by arch specific code once the early allocator (memblock or bootmem) * has been activated and all other subsystems have already allocated/reserved * memory. This function allows to create custom reserved areas. * * If @fixed is true, reserve contiguous area at exactly @base. If false, * reserve in range from @base to @limit. */ int __init cma_declare_contiguous_nid(phys_addr_t base, phys_addr_t size, phys_addr_t limit, phys_addr_t alignment, unsigned int order_per_bit, bool fixed, const char *name, struct cma **res_cma, int nid) { phys_addr_t memblock_end = memblock_end_of_DRAM(); phys_addr_t highmem_start; int ret; /* * We can't use __pa(high_memory) directly, since high_memory * isn't a valid direct map VA, and DEBUG_VIRTUAL will (validly) * complain. Find the boundary by adding one to the last valid * address. */ highmem_start = __pa(high_memory - 1) + 1; pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n", __func__, &size, &base, &limit, &alignment); if (cma_area_count == ARRAY_SIZE(cma_areas)) { pr_err("Not enough slots for CMA reserved regions!\n"); return -ENOSPC; } if (!size) return -EINVAL; if (alignment && !is_power_of_2(alignment)) return -EINVAL; if (!IS_ENABLED(CONFIG_NUMA)) nid = NUMA_NO_NODE; /* Sanitise input arguments. */ alignment = max_t(phys_addr_t, alignment, CMA_MIN_ALIGNMENT_BYTES); if (fixed && base & (alignment - 1)) { ret = -EINVAL; pr_err("Region at %pa must be aligned to %pa bytes\n", &base, &alignment); goto err; } base = ALIGN(base, alignment); size = ALIGN(size, alignment); limit &= ~(alignment - 1); if (!base) fixed = false; /* size should be aligned with order_per_bit */ if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit)) return -EINVAL; /* * If allocating at a fixed base the request region must not cross the * low/high memory boundary. */ if (fixed && base < highmem_start && base + size > highmem_start) { ret = -EINVAL; pr_err("Region at %pa defined on low/high memory boundary (%pa)\n", &base, &highmem_start); goto err; } /* * If the limit is unspecified or above the memblock end, its effective * value will be the memblock end. Set it explicitly to simplify further * checks. */ if (limit == 0 || limit > memblock_end) limit = memblock_end; if (base + size > limit) { ret = -EINVAL; pr_err("Size (%pa) of region at %pa exceeds limit (%pa)\n", &size, &base, &limit); goto err; } /* Reserve memory */ if (fixed) { if (memblock_is_region_reserved(base, size) || memblock_reserve(base, size) < 0) { ret = -EBUSY; goto err; } } else { phys_addr_t addr = 0; /* * If there is enough memory, try a bottom-up allocation first. * It will place the new cma area close to the start of the node * and guarantee that the compaction is moving pages out of the * cma area and not into it. * Avoid using first 4GB to not interfere with constrained zones * like DMA/DMA32. */ #ifdef CONFIG_PHYS_ADDR_T_64BIT if (!memblock_bottom_up() && memblock_end >= SZ_4G + size) { memblock_set_bottom_up(true); addr = memblock_alloc_range_nid(size, alignment, SZ_4G, limit, nid, true); memblock_set_bottom_up(false); } #endif /* * All pages in the reserved area must come from the same zone. * If the requested region crosses the low/high memory boundary, * try allocating from high memory first and fall back to low * memory in case of failure. */ if (!addr && base < highmem_start && limit > highmem_start) { addr = memblock_alloc_range_nid(size, alignment, highmem_start, limit, nid, true); limit = highmem_start; } if (!addr) { addr = memblock_alloc_range_nid(size, alignment, base, limit, nid, true); if (!addr) { ret = -ENOMEM; goto err; } } /* * kmemleak scans/reads tracked objects for pointers to other * objects but this address isn't mapped and accessible */ kmemleak_ignore_phys(addr); base = addr; } ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma); if (ret) goto free_mem; pr_info("Reserved %ld MiB at %pa on node %d\n", (unsigned long)size / SZ_1M, &base, nid); return 0; free_mem: memblock_phys_free(base, size); err: pr_err("Failed to reserve %ld MiB on node %d\n", (unsigned long)size / SZ_1M, nid); return ret; } static void cma_debug_show_areas(struct cma *cma) { unsigned long next_zero_bit, next_set_bit, nr_zero; unsigned long start = 0; unsigned long nr_part, nr_total = 0; unsigned long nbits = cma_bitmap_maxno(cma); spin_lock_irq(&cma->lock); pr_info("number of available pages: "); for (;;) { next_zero_bit = find_next_zero_bit(cma->bitmap, nbits, start); if (next_zero_bit >= nbits) break; next_set_bit = find_next_bit(cma->bitmap, nbits, next_zero_bit); nr_zero = next_set_bit - next_zero_bit; nr_part = nr_zero << cma->order_per_bit; pr_cont("%s%lu@%lu", nr_total ? "+" : "", nr_part, next_zero_bit); nr_total += nr_part; start = next_zero_bit + nr_zero; } pr_cont("=> %lu free of %lu total pages\n", nr_total, cma->count); spin_unlock_irq(&cma->lock); } /** * cma_alloc() - allocate pages from contiguous area * @cma: Contiguous memory region for which the allocation is performed. * @count: Requested number of pages. * @align: Requested alignment of pages (in PAGE_SIZE order). * @no_warn: Avoid printing message about failed allocation * * This function allocates part of contiguous memory on specific * contiguous memory area. */ struct page *cma_alloc(struct cma *cma, unsigned long count, unsigned int align, bool no_warn) { unsigned long mask, offset; unsigned long pfn = -1; unsigned long start = 0; unsigned long bitmap_maxno, bitmap_no, bitmap_count; unsigned long i; struct page *page = NULL; int ret = -ENOMEM; const char *name = cma ? cma->name : NULL; trace_cma_alloc_start(name, count, align); if (!cma || !cma->count || !cma->bitmap) return page; pr_debug("%s(cma %p, name: %s, count %lu, align %d)\n", __func__, (void *)cma, cma->name, count, align); if (!count) return page; mask = cma_bitmap_aligned_mask(cma, align); offset = cma_bitmap_aligned_offset(cma, align); bitmap_maxno = cma_bitmap_maxno(cma); bitmap_count = cma_bitmap_pages_to_bits(cma, count); if (bitmap_count > bitmap_maxno) return page; for (;;) { spin_lock_irq(&cma->lock); bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, bitmap_maxno, start, bitmap_count, mask, offset); if (bitmap_no >= bitmap_maxno) { spin_unlock_irq(&cma->lock); break; } bitmap_set(cma->bitmap, bitmap_no, bitmap_count); /* * It's safe to drop the lock here. We've marked this region for * our exclusive use. If the migration fails we will take the * lock again and unmark it. */ spin_unlock_irq(&cma->lock); pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit); mutex_lock(&cma_mutex); ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA, GFP_KERNEL | (no_warn ? __GFP_NOWARN : 0)); mutex_unlock(&cma_mutex); if (ret == 0) { page = pfn_to_page(pfn); break; } cma_clear_bitmap(cma, pfn, count); if (ret != -EBUSY) break; pr_debug("%s(): memory range at pfn 0x%lx %p is busy, retrying\n", __func__, pfn, pfn_to_page(pfn)); trace_cma_alloc_busy_retry(cma->name, pfn, pfn_to_page(pfn), count, align); /* try again with a bit different memory target */ start = bitmap_no + mask + 1; } /* * CMA can allocate multiple page blocks, which results in different * blocks being marked with different tags. Reset the tags to ignore * those page blocks. */ if (page) { for (i = 0; i < count; i++) page_kasan_tag_reset(nth_page(page, i)); } if (ret && !no_warn) { pr_err_ratelimited("%s: %s: alloc failed, req-size: %lu pages, ret: %d\n", __func__, cma->name, count, ret); cma_debug_show_areas(cma); } pr_debug("%s(): returned %p\n", __func__, page); trace_cma_alloc_finish(name, pfn, page, count, align, ret); if (page) { count_vm_event(CMA_ALLOC_SUCCESS); cma_sysfs_account_success_pages(cma, count); } else { count_vm_event(CMA_ALLOC_FAIL); cma_sysfs_account_fail_pages(cma, count); } return page; } bool cma_pages_valid(struct cma *cma, const struct page *pages, unsigned long count) { unsigned long pfn; if (!cma || !pages) return false; pfn = page_to_pfn(pages); if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) { pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count); return false; } return true; } /** * cma_release() - release allocated pages * @cma: Contiguous memory region for which the allocation is performed. * @pages: Allocated pages. * @count: Number of allocated pages. * * This function releases memory allocated by cma_alloc(). * It returns false when provided pages do not belong to contiguous area and * true otherwise. */ bool cma_release(struct cma *cma, const struct page *pages, unsigned long count) { unsigned long pfn; if (!cma_pages_valid(cma, pages, count)) return false; pr_debug("%s(page %p, count %lu)\n", __func__, (void *)pages, count); pfn = page_to_pfn(pages); VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); free_contig_range(pfn, count); cma_clear_bitmap(cma, pfn, count); cma_sysfs_account_release_pages(cma, count); trace_cma_release(cma->name, pfn, pages, count); return true; } int cma_for_each_area(int (*it)(struct cma *cma, void *data), void *data) { int i; for (i = 0; i < cma_area_count; i++) { int ret = it(&cma_areas[i], data); if (ret) return ret; } return 0; }