diff options
Diffstat (limited to 'mm/cma.c')
-rw-r--r-- | mm/cma.c | 543 |
1 files changed, 543 insertions, 0 deletions
diff --git a/mm/cma.c b/mm/cma.c new file mode 100644 index 000000000..3c3f1436f --- /dev/null +++ b/mm/cma.c @@ -0,0 +1,543 @@ +// 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 + +#ifdef CONFIG_CMA_DEBUG +#ifndef DEBUG +# define DEBUG +#endif +#endif +#define CREATE_TRACE_POINTS + +#include <linux/memblock.h> +#include <linux/err.h> +#include <linux/mm.h> +#include <linux/mutex.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 "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 int count) +{ + unsigned long bitmap_no, bitmap_count; + + bitmap_no = (pfn - cma->base_pfn) >> cma->order_per_bit; + bitmap_count = cma_bitmap_pages_to_bits(cma, count); + + mutex_lock(&cma->lock); + bitmap_clear(cma->bitmap, bitmap_no, bitmap_count); + mutex_unlock(&cma->lock); +} + +static void __init cma_activate_area(struct cma *cma) +{ + unsigned long base_pfn = cma->base_pfn, pfn = base_pfn; + unsigned i = cma->count >> pageblock_order; + struct zone *zone; + + cma->bitmap = bitmap_zalloc(cma_bitmap_maxno(cma), GFP_KERNEL); + if (!cma->bitmap) + goto out_error; + + WARN_ON_ONCE(!pfn_valid(pfn)); + zone = page_zone(pfn_to_page(pfn)); + + do { + unsigned j; + + base_pfn = pfn; + for (j = pageblock_nr_pages; j; --j, pfn++) { + WARN_ON_ONCE(!pfn_valid(pfn)); + /* + * alloc_contig_range requires the pfn range + * specified to be in the same zone. Make this + * simple by forcing the entire CMA resv range + * to be in the same zone. + */ + if (page_zone(pfn_to_page(pfn)) != zone) + goto not_in_zone; + } + init_cma_reserved_pageblock(pfn_to_page(base_pfn)); + } while (--i); + + mutex_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: + 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); + +/** + * 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; + phys_addr_t alignment; + + /* 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 */ + alignment = PAGE_SIZE << + max_t(unsigned long, MAX_ORDER - 1, pageblock_order); + + /* alignment should be aligned with order_per_bit */ + if (!IS_ALIGNED(alignment >> PAGE_SHIFT, 1 << order_per_bit)) + return -EINVAL; + + if (ALIGN(base, alignment) != base || ALIGN(size, alignment) != size) + 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 = 0; + + /* + * 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; + + /* + * Sanitise input arguments. + * Pages both ends in CMA area could be merged into adjacent unmovable + * migratetype page by page allocator's buddy algorithm. In the case, + * you couldn't get a contiguous memory, which is not what we want. + */ + alignment = max(alignment, (phys_addr_t)PAGE_SIZE << + max_t(unsigned long, MAX_ORDER - 1, pageblock_order)); + 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; + + /* + * 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 (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\n", (unsigned long)size / SZ_1M, + &base); + return 0; + +free_mem: + memblock_free(base, size); +err: + pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M); + return ret; +} + +#ifdef CONFIG_CMA_DEBUG +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); + + mutex_lock(&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); + mutex_unlock(&cma->lock); +} +#else +static inline void cma_debug_show_areas(struct cma *cma) { } +#endif + +/** + * 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, size_t 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; + size_t i; + struct page *page = NULL; + int ret = -ENOMEM; + + if (!cma || !cma->count || !cma->bitmap) + return NULL; + + pr_debug("%s(cma %p, count %zu, align %d)\n", __func__, (void *)cma, + count, align); + + if (!count) + return NULL; + + 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 NULL; + + for (;;) { + mutex_lock(&cma->lock); + bitmap_no = bitmap_find_next_zero_area_off(cma->bitmap, + bitmap_maxno, start, bitmap_count, mask, + offset); + if (bitmap_no >= bitmap_maxno) { + mutex_unlock(&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. + */ + mutex_unlock(&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 %p is busy, retrying\n", + __func__, pfn_to_page(pfn)); + /* try again with a bit different memory target */ + start = bitmap_no + mask + 1; + } + + trace_cma_alloc(pfn, page, count, align); + + /* + * 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("%s: alloc failed, req-size: %zu pages, ret: %d\n", + __func__, count, ret); + cma_debug_show_areas(cma); + } + + pr_debug("%s(): returned %p\n", __func__, page); + return page; +} + +/** + * 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 int count) +{ + unsigned long pfn; + + if (!cma || !pages) + return false; + + pr_debug("%s(page %p)\n", __func__, (void *)pages); + + pfn = page_to_pfn(pages); + + if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count) + return false; + + VM_BUG_ON(pfn + count > cma->base_pfn + cma->count); + + free_contig_range(pfn, count); + cma_clear_bitmap(cma, pfn, count); + trace_cma_release(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; +} |