1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2012 ARM Ltd. 4 * Copyright (C) 2020 Google LLC 5 */ 6 #include <linux/debugfs.h> 7 #include <linux/dma-direct.h> 8 #include <linux/dma-noncoherent.h> 9 #include <linux/dma-contiguous.h> 10 #include <linux/init.h> 11 #include <linux/genalloc.h> 12 #include <linux/set_memory.h> 13 #include <linux/slab.h> 14 #include <linux/workqueue.h> 15 16 static struct gen_pool *atomic_pool_dma __ro_after_init; 17 static unsigned long pool_size_dma; 18 static struct gen_pool *atomic_pool_dma32 __ro_after_init; 19 static unsigned long pool_size_dma32; 20 static struct gen_pool *atomic_pool_kernel __ro_after_init; 21 static unsigned long pool_size_kernel; 22 23 /* Size can be defined by the coherent_pool command line */ 24 static size_t atomic_pool_size; 25 26 /* Dynamic background expansion when the atomic pool is near capacity */ 27 static struct work_struct atomic_pool_work; 28 29 static int __init early_coherent_pool(char *p) 30 { 31 atomic_pool_size = memparse(p, &p); 32 return 0; 33 } 34 early_param("coherent_pool", early_coherent_pool); 35 36 static void __init dma_atomic_pool_debugfs_init(void) 37 { 38 struct dentry *root; 39 40 root = debugfs_create_dir("dma_pools", NULL); 41 if (IS_ERR_OR_NULL(root)) 42 return; 43 44 debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma); 45 debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32); 46 debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel); 47 } 48 49 static void dma_atomic_pool_size_add(gfp_t gfp, size_t size) 50 { 51 if (gfp & __GFP_DMA) 52 pool_size_dma += size; 53 else if (gfp & __GFP_DMA32) 54 pool_size_dma32 += size; 55 else 56 pool_size_kernel += size; 57 } 58 59 static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, 60 gfp_t gfp) 61 { 62 unsigned int order; 63 struct page *page; 64 void *addr; 65 int ret = -ENOMEM; 66 67 /* Cannot allocate larger than MAX_ORDER-1 */ 68 order = min(get_order(pool_size), MAX_ORDER-1); 69 70 do { 71 pool_size = 1 << (PAGE_SHIFT + order); 72 73 if (dev_get_cma_area(NULL)) 74 page = dma_alloc_from_contiguous(NULL, 1 << order, 75 order, false); 76 else 77 page = alloc_pages(gfp, order); 78 } while (!page && order-- > 0); 79 if (!page) 80 goto out; 81 82 arch_dma_prep_coherent(page, pool_size); 83 84 #ifdef CONFIG_DMA_DIRECT_REMAP 85 addr = dma_common_contiguous_remap(page, pool_size, 86 pgprot_dmacoherent(PAGE_KERNEL), 87 __builtin_return_address(0)); 88 if (!addr) 89 goto free_page; 90 #else 91 addr = page_to_virt(page); 92 #endif 93 /* 94 * Memory in the atomic DMA pools must be unencrypted, the pools do not 95 * shrink so no re-encryption occurs in dma_direct_free_pages(). 96 */ 97 ret = set_memory_decrypted((unsigned long)page_to_virt(page), 98 1 << order); 99 if (ret) 100 goto remove_mapping; 101 ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), 102 pool_size, NUMA_NO_NODE); 103 if (ret) 104 goto encrypt_mapping; 105 106 dma_atomic_pool_size_add(gfp, pool_size); 107 return 0; 108 109 encrypt_mapping: 110 ret = set_memory_encrypted((unsigned long)page_to_virt(page), 111 1 << order); 112 if (WARN_ON_ONCE(ret)) { 113 /* Decrypt succeeded but encrypt failed, purposely leak */ 114 goto out; 115 } 116 remove_mapping: 117 #ifdef CONFIG_DMA_DIRECT_REMAP 118 dma_common_free_remap(addr, pool_size); 119 #endif 120 free_page: __maybe_unused 121 if (!dma_release_from_contiguous(NULL, page, 1 << order)) 122 __free_pages(page, order); 123 out: 124 return ret; 125 } 126 127 static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp) 128 { 129 if (pool && gen_pool_avail(pool) < atomic_pool_size) 130 atomic_pool_expand(pool, gen_pool_size(pool), gfp); 131 } 132 133 static void atomic_pool_work_fn(struct work_struct *work) 134 { 135 if (IS_ENABLED(CONFIG_ZONE_DMA)) 136 atomic_pool_resize(atomic_pool_dma, 137 GFP_KERNEL | GFP_DMA); 138 if (IS_ENABLED(CONFIG_ZONE_DMA32)) 139 atomic_pool_resize(atomic_pool_dma32, 140 GFP_KERNEL | GFP_DMA32); 141 atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL); 142 } 143 144 static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size, 145 gfp_t gfp) 146 { 147 struct gen_pool *pool; 148 int ret; 149 150 pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); 151 if (!pool) 152 return NULL; 153 154 gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL); 155 156 ret = atomic_pool_expand(pool, pool_size, gfp); 157 if (ret) { 158 gen_pool_destroy(pool); 159 pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n", 160 pool_size >> 10, &gfp); 161 return NULL; 162 } 163 164 pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n", 165 gen_pool_size(pool) >> 10, &gfp); 166 return pool; 167 } 168 169 static int __init dma_atomic_pool_init(void) 170 { 171 int ret = 0; 172 173 /* 174 * If coherent_pool was not used on the command line, default the pool 175 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1. 176 */ 177 if (!atomic_pool_size) { 178 unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K); 179 pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES); 180 atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K); 181 } 182 INIT_WORK(&atomic_pool_work, atomic_pool_work_fn); 183 184 atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size, 185 GFP_KERNEL); 186 if (!atomic_pool_kernel) 187 ret = -ENOMEM; 188 if (IS_ENABLED(CONFIG_ZONE_DMA)) { 189 atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size, 190 GFP_KERNEL | GFP_DMA); 191 if (!atomic_pool_dma) 192 ret = -ENOMEM; 193 } 194 if (IS_ENABLED(CONFIG_ZONE_DMA32)) { 195 atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size, 196 GFP_KERNEL | GFP_DMA32); 197 if (!atomic_pool_dma32) 198 ret = -ENOMEM; 199 } 200 201 dma_atomic_pool_debugfs_init(); 202 return ret; 203 } 204 postcore_initcall(dma_atomic_pool_init); 205 206 static inline struct gen_pool *dev_to_pool(struct device *dev) 207 { 208 u64 phys_mask; 209 gfp_t gfp; 210 211 gfp = dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask, 212 &phys_mask); 213 if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp == GFP_DMA) 214 return atomic_pool_dma; 215 if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp == GFP_DMA32) 216 return atomic_pool_dma32; 217 return atomic_pool_kernel; 218 } 219 220 static bool dma_in_atomic_pool(struct device *dev, void *start, size_t size) 221 { 222 struct gen_pool *pool = dev_to_pool(dev); 223 224 if (unlikely(!pool)) 225 return false; 226 return gen_pool_has_addr(pool, (unsigned long)start, size); 227 } 228 229 void *dma_alloc_from_pool(struct device *dev, size_t size, 230 struct page **ret_page, gfp_t flags) 231 { 232 struct gen_pool *pool = dev_to_pool(dev); 233 unsigned long val; 234 void *ptr = NULL; 235 236 if (!pool) { 237 WARN(1, "%pGg atomic pool not initialised!\n", &flags); 238 return NULL; 239 } 240 241 val = gen_pool_alloc(pool, size); 242 if (val) { 243 phys_addr_t phys = gen_pool_virt_to_phys(pool, val); 244 245 *ret_page = pfn_to_page(__phys_to_pfn(phys)); 246 ptr = (void *)val; 247 memset(ptr, 0, size); 248 } 249 if (gen_pool_avail(pool) < atomic_pool_size) 250 schedule_work(&atomic_pool_work); 251 252 return ptr; 253 } 254 255 bool dma_free_from_pool(struct device *dev, void *start, size_t size) 256 { 257 struct gen_pool *pool = dev_to_pool(dev); 258 259 if (!dma_in_atomic_pool(dev, start, size)) 260 return false; 261 gen_pool_free(pool, (unsigned long)start, size); 262 return true; 263 } 264