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*参照元 [#fa1a18a0] #backlinks *説明 [#ef6a6611] -パス: [[linux-4.4.1/mm/cma.c]] -FIXME: これは何？ --説明 **引数 [#ifd6864d] -phys_addr_t base -- --[[linux-4.4.1/phys_addr_t]] -phys_addr_t size -- -phys_addr_t limit -- -phys_addr_t alignment -- -unsigned int order_per_bit -- -bool fixed -- -struct cma **res_cma -- --[[linux-4.4.1/cma]] **返り値 [#m5152279] -int -- **参考 [#q668b5e2] *実装 [#ka25b461] /** * cma_declare_contiguous() - 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 * @res_cma: Pointer to store the created cma region. * * 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(phys_addr_t base, phys_addr_t size, phys_addr_t limit, phys_addr_t alignment, unsigned int order_per_bit, bool fixed, struct cma **res_cma) { phys_addr_t memblock_end = memblock_end_of_DRAM(); phys_addr_t highmem_start; int ret = 0; - --[[linux-4.4.1/__init]] --[[linux-4.4.1/memblock_end_of_DRAM()]] #ifdef CONFIG_X86 /* * high_memory isn't direct mapped memory so retrieving its physical * address isn't appropriate. But it would be useful to check the * physical address of the highmem boundary so it's justifiable to get * the physical address from it. On x86 there is a validation check for * this case, so the following workaround is needed to avoid it. */ highmem_start = __pa_nodebug(high_memory); #else highmem_start = __pa(high_memory); #endif - --[[linux-4.4.1/CONFIG_X86]] --[[linux-4.4.1/__pa_nodebug()]] --[[linux-4.4.1/high_memory(global)]] --[[linux-4.4.1/__pa()]] pr_debug("%s(size %pa, base %pa, limit %pa alignment %pa)\n", __func__, &size, &base, &limit, &alignment); - --[[linux-4.4.1/pr_debug()]] if (cma_area_count == ARRAY_SIZE(cma_areas)) { pr_err("Not enough slots for CMA reserved regions!\n"); return -ENOSPC; } - --[[linux-4.4.1/ARRAY_SIZE()]] --[[linux-4.4.1/cma_areas(global)]] --[[linux-4.4.1/pr_err()]] if (!size) return -EINVAL; if (alignment && !is_power_of_2(alignment)) return -EINVAL; - --[[linux-4.4.1/is_power_of_2()]] /* * 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(MAX_ORDER - 1, pageblock_order)); base = ALIGN(base, alignment); size = ALIGN(size, alignment); limit &= ~(alignment - 1); - --[[linux-4.4.1/ALIGN()]] if (!base) fixed = false; /* size should be aligned with order_per_bit */ if (!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit)) return -EINVAL; - --[[linux-4.4.1/IS_ALIGNED()]] /* * 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; } - --[[linux-4.4.1/highmem_start(global)]] /* * 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; /* Reserve memory */ if (fixed) { if (memblock_is_region_reserved(base, size) || memblock_reserve(base, size) < 0) { ret = -EBUSY; goto err; } - --[[linux-4.4.1/memblock_is_region_reserved()]] --[[linux-4.4.1/memblock_reserve()]] } 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(size, alignment, highmem_start, limit, MEMBLOCK_NONE); limit = highmem_start; } - --[[linux-4.4.1/memblock_alloc_range()]] if (!addr) { addr = memblock_alloc_range(size, alignment, base, limit, MEMBLOCK_NONE); 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_to_virt(addr)); base = addr; - --[[linux-4.4.1/kmemleak_ignore()]] --[[linux-4.4.1/phys_to_virt()]] } ret = cma_init_reserved_mem(base, size, order_per_bit, res_cma); if (ret) goto err; - --[[linux-4.4.1/cma_init_reserved_mem()]] pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M, &base); return 0; - --[[linux-4.4.1/pr_info()]] err: pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M); return ret; - --[[linux-4.4.1/pr_err()]] } *コメント [#r8e8cade]
