// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2012 ARM Ltd. * Copyright (C) 2020 Google LLC */ #include #include #include #include #include #include #include #include #include static struct gen_pool *atomic_pool_dma __ro_after_init; static unsigned long pool_size_dma; static struct gen_pool *atomic_pool_dma32 __ro_after_init; static unsigned long pool_size_dma32; static struct gen_pool *atomic_pool_kernel __ro_after_init; static unsigned long pool_size_kernel; /* Size can be defined by the coherent_pool command line */ static size_t atomic_pool_size; /* Dynamic background expansion when the atomic pool is near capacity */ static struct work_struct atomic_pool_work; static int __init early_coherent_pool(char *p) { atomic_pool_size = memparse(p, &p); return 0; } early_param("coherent_pool", early_coherent_pool); static void __init dma_atomic_pool_debugfs_init(void) { struct dentry *root; root = debugfs_create_dir("dma_pools", NULL); if (IS_ERR_OR_NULL(root)) return; debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma); debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32); debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel); } static void dma_atomic_pool_size_add(gfp_t gfp, size_t size) { if (gfp & __GFP_DMA) pool_size_dma += size; else if (gfp & __GFP_DMA32) pool_size_dma32 += size; else pool_size_kernel += size; } static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, gfp_t gfp) { unsigned int order; struct page *page; void *addr; int ret = -ENOMEM; /* Cannot allocate larger than MAX_ORDER-1 */ order = min(get_order(pool_size), MAX_ORDER-1); do { pool_size = 1 << (PAGE_SHIFT + order); if (dev_get_cma_area(NULL)) page = dma_alloc_from_contiguous(NULL, 1 << order, order, false); else page = alloc_pages(gfp, order); } while (!page && order-- > 0); if (!page) goto out; arch_dma_prep_coherent(page, pool_size); #ifdef CONFIG_DMA_DIRECT_REMAP addr = dma_common_contiguous_remap(page, pool_size, pgprot_dmacoherent(PAGE_KERNEL), __builtin_return_address(0)); if (!addr) goto free_page; #else addr = page_to_virt(page); #endif /* * Memory in the atomic DMA pools must be unencrypted, the pools do not * shrink so no re-encryption occurs in dma_direct_free_pages(). */ ret = set_memory_decrypted((unsigned long)page_to_virt(page), 1 << order); if (ret) goto remove_mapping; ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), pool_size, NUMA_NO_NODE); if (ret) goto encrypt_mapping; dma_atomic_pool_size_add(gfp, pool_size); return 0; encrypt_mapping: ret = set_memory_encrypted((unsigned long)page_to_virt(page), 1 << order); if (WARN_ON_ONCE(ret)) { /* Decrypt succeeded but encrypt failed, purposely leak */ goto out; } remove_mapping: #ifdef CONFIG_DMA_DIRECT_REMAP dma_common_free_remap(addr, pool_size); #endif free_page: __maybe_unused if (!dma_release_from_contiguous(NULL, page, 1 << order)) __free_pages(page, order); out: return ret; } static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp) { if (pool && gen_pool_avail(pool) < atomic_pool_size) atomic_pool_expand(pool, gen_pool_size(pool), gfp); } static void atomic_pool_work_fn(struct work_struct *work) { if (IS_ENABLED(CONFIG_ZONE_DMA)) atomic_pool_resize(atomic_pool_dma, GFP_KERNEL | GFP_DMA); if (IS_ENABLED(CONFIG_ZONE_DMA32)) atomic_pool_resize(atomic_pool_dma32, GFP_KERNEL | GFP_DMA32); atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL); } static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size, gfp_t gfp) { struct gen_pool *pool; int ret; pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); if (!pool) return NULL; gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL); ret = atomic_pool_expand(pool, pool_size, gfp); if (ret) { gen_pool_destroy(pool); pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n", pool_size >> 10, &gfp); return NULL; } pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n", gen_pool_size(pool) >> 10, &gfp); return pool; } static int __init dma_atomic_pool_init(void) { int ret = 0; /* * If coherent_pool was not used on the command line, default the pool * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1. */ if (!atomic_pool_size) { unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K); pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES); atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K); } INIT_WORK(&atomic_pool_work, atomic_pool_work_fn); atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size, GFP_KERNEL); if (!atomic_pool_kernel) ret = -ENOMEM; if (IS_ENABLED(CONFIG_ZONE_DMA)) { atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size, GFP_KERNEL | GFP_DMA); if (!atomic_pool_dma) ret = -ENOMEM; } if (IS_ENABLED(CONFIG_ZONE_DMA32)) { atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size, GFP_KERNEL | GFP_DMA32); if (!atomic_pool_dma32) ret = -ENOMEM; } dma_atomic_pool_debugfs_init(); return ret; } postcore_initcall(dma_atomic_pool_init); static inline struct gen_pool *dev_to_pool(struct device *dev) { u64 phys_mask; gfp_t gfp; gfp = dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask, &phys_mask); if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp == GFP_DMA) return atomic_pool_dma; if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp == GFP_DMA32) return atomic_pool_dma32; return atomic_pool_kernel; } static bool dma_in_atomic_pool(struct device *dev, void *start, size_t size) { struct gen_pool *pool = dev_to_pool(dev); if (unlikely(!pool)) return false; return gen_pool_has_addr(pool, (unsigned long)start, size); } void *dma_alloc_from_pool(struct device *dev, size_t size, struct page **ret_page, gfp_t flags) { struct gen_pool *pool = dev_to_pool(dev); unsigned long val; void *ptr = NULL; if (!pool) { WARN(1, "%pGg atomic pool not initialised!\n", &flags); return NULL; } val = gen_pool_alloc(pool, size); if (val) { phys_addr_t phys = gen_pool_virt_to_phys(pool, val); *ret_page = pfn_to_page(__phys_to_pfn(phys)); ptr = (void *)val; memset(ptr, 0, size); } if (gen_pool_avail(pool) < atomic_pool_size) schedule_work(&atomic_pool_work); return ptr; } bool dma_free_from_pool(struct device *dev, void *start, size_t size) { struct gen_pool *pool = dev_to_pool(dev); if (!dma_in_atomic_pool(dev, start, size)) return false; gen_pool_free(pool, (unsigned long)start, size); return true; }