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/init.h> 10 #include <linux/genalloc.h> 11 #include <linux/set_memory.h> 12 #include <linux/slab.h> 13 #include <linux/workqueue.h> 14 15 static struct gen_pool *atomic_pool_dma __ro_after_init; 16 static unsigned long pool_size_dma; 17 static struct gen_pool *atomic_pool_dma32 __ro_after_init; 18 static unsigned long pool_size_dma32; 19 static struct gen_pool *atomic_pool_kernel __ro_after_init; 20 static unsigned long pool_size_kernel; 21 22 /* Size can be defined by the coherent_pool command line */ 23 static size_t atomic_pool_size; 24 25 /* Dynamic background expansion when the atomic pool is near capacity */ 26 static struct work_struct atomic_pool_work; 27 28 static int __init early_coherent_pool(char *p) 29 { 30 atomic_pool_size = memparse(p, &p); 31 return 0; 32 } 33 early_param("coherent_pool", early_coherent_pool); 34 35 static void __init dma_atomic_pool_debugfs_init(void) 36 { 37 struct dentry *root; 38 39 root = debugfs_create_dir("dma_pools", NULL); 40 if (IS_ERR_OR_NULL(root)) 41 return; 42 43 debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma); 44 debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32); 45 debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel); 46 } 47 48 static void dma_atomic_pool_size_add(gfp_t gfp, size_t size) 49 { 50 if (gfp & __GFP_DMA) 51 pool_size_dma += size; 52 else if (gfp & __GFP_DMA32) 53 pool_size_dma32 += size; 54 else 55 pool_size_kernel += size; 56 } 57 58 static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, 59 gfp_t gfp) 60 { 61 unsigned int order; 62 struct page *page; 63 void *addr; 64 int ret = -ENOMEM; 65 66 /* Cannot allocate larger than MAX_ORDER-1 */ 67 order = min(get_order(pool_size), MAX_ORDER-1); 68 69 do { 70 pool_size = 1 << (PAGE_SHIFT + order); 71 page = alloc_pages(gfp, order); 72 } while (!page && order-- > 0); 73 if (!page) 74 goto out; 75 76 arch_dma_prep_coherent(page, pool_size); 77 78 #ifdef CONFIG_DMA_DIRECT_REMAP 79 addr = dma_common_contiguous_remap(page, pool_size, 80 pgprot_dmacoherent(PAGE_KERNEL), 81 __builtin_return_address(0)); 82 if (!addr) 83 goto free_page; 84 #else 85 addr = page_to_virt(page); 86 #endif 87 /* 88 * Memory in the atomic DMA pools must be unencrypted, the pools do not 89 * shrink so no re-encryption occurs in dma_direct_free_pages(). 90 */ 91 ret = set_memory_decrypted((unsigned long)page_to_virt(page), 92 1 << order); 93 if (ret) 94 goto remove_mapping; 95 ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), 96 pool_size, NUMA_NO_NODE); 97 if (ret) 98 goto encrypt_mapping; 99 100 dma_atomic_pool_size_add(gfp, pool_size); 101 return 0; 102 103 encrypt_mapping: 104 ret = set_memory_encrypted((unsigned long)page_to_virt(page), 105 1 << order); 106 if (WARN_ON_ONCE(ret)) { 107 /* Decrypt succeeded but encrypt failed, purposely leak */ 108 goto out; 109 } 110 remove_mapping: 111 #ifdef CONFIG_DMA_DIRECT_REMAP 112 dma_common_free_remap(addr, pool_size); 113 #endif 114 free_page: __maybe_unused 115 __free_pages(page, order); 116 out: 117 return ret; 118 } 119 120 static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp) 121 { 122 if (pool && gen_pool_avail(pool) < atomic_pool_size) 123 atomic_pool_expand(pool, gen_pool_size(pool), gfp); 124 } 125 126 static void atomic_pool_work_fn(struct work_struct *work) 127 { 128 if (IS_ENABLED(CONFIG_ZONE_DMA)) 129 atomic_pool_resize(atomic_pool_dma, 130 GFP_KERNEL | GFP_DMA); 131 if (IS_ENABLED(CONFIG_ZONE_DMA32)) 132 atomic_pool_resize(atomic_pool_dma32, 133 GFP_KERNEL | GFP_DMA32); 134 atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL); 135 } 136 137 static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size, 138 gfp_t gfp) 139 { 140 struct gen_pool *pool; 141 int ret; 142 143 pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); 144 if (!pool) 145 return NULL; 146 147 gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL); 148 149 ret = atomic_pool_expand(pool, pool_size, gfp); 150 if (ret) { 151 gen_pool_destroy(pool); 152 pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n", 153 pool_size >> 10, &gfp); 154 return NULL; 155 } 156 157 pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n", 158 gen_pool_size(pool) >> 10, &gfp); 159 return pool; 160 } 161 162 static int __init dma_atomic_pool_init(void) 163 { 164 int ret = 0; 165 166 /* 167 * If coherent_pool was not used on the command line, default the pool 168 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1. 169 */ 170 if (!atomic_pool_size) { 171 unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K); 172 pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES); 173 atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K); 174 } 175 INIT_WORK(&atomic_pool_work, atomic_pool_work_fn); 176 177 atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size, 178 GFP_KERNEL); 179 if (!atomic_pool_kernel) 180 ret = -ENOMEM; 181 if (IS_ENABLED(CONFIG_ZONE_DMA)) { 182 atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size, 183 GFP_KERNEL | GFP_DMA); 184 if (!atomic_pool_dma) 185 ret = -ENOMEM; 186 } 187 if (IS_ENABLED(CONFIG_ZONE_DMA32)) { 188 atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size, 189 GFP_KERNEL | GFP_DMA32); 190 if (!atomic_pool_dma32) 191 ret = -ENOMEM; 192 } 193 194 dma_atomic_pool_debugfs_init(); 195 return ret; 196 } 197 postcore_initcall(dma_atomic_pool_init); 198 199 static inline struct gen_pool *dma_guess_pool_from_device(struct device *dev) 200 { 201 u64 phys_mask; 202 gfp_t gfp; 203 204 gfp = dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask, 205 &phys_mask); 206 if (IS_ENABLED(CONFIG_ZONE_DMA) && gfp == GFP_DMA) 207 return atomic_pool_dma; 208 if (IS_ENABLED(CONFIG_ZONE_DMA32) && gfp == GFP_DMA32) 209 return atomic_pool_dma32; 210 return atomic_pool_kernel; 211 } 212 213 static inline struct gen_pool *dma_get_safer_pool(struct gen_pool *bad_pool) 214 { 215 if (bad_pool == atomic_pool_kernel) 216 return atomic_pool_dma32 ? : atomic_pool_dma; 217 218 if (bad_pool == atomic_pool_dma32) 219 return atomic_pool_dma; 220 221 return NULL; 222 } 223 224 static inline struct gen_pool *dma_guess_pool(struct device *dev, 225 struct gen_pool *bad_pool) 226 { 227 if (bad_pool) 228 return dma_get_safer_pool(bad_pool); 229 230 return dma_guess_pool_from_device(dev); 231 } 232 233 void *dma_alloc_from_pool(struct device *dev, size_t size, 234 struct page **ret_page, gfp_t flags) 235 { 236 struct gen_pool *pool = NULL; 237 unsigned long val = 0; 238 void *ptr = NULL; 239 phys_addr_t phys; 240 241 while (1) { 242 pool = dma_guess_pool(dev, pool); 243 if (!pool) { 244 WARN(1, "Failed to get suitable pool for %s\n", 245 dev_name(dev)); 246 break; 247 } 248 249 val = gen_pool_alloc(pool, size); 250 if (!val) 251 continue; 252 253 phys = gen_pool_virt_to_phys(pool, val); 254 if (dma_coherent_ok(dev, phys, size)) 255 break; 256 257 gen_pool_free(pool, val, size); 258 val = 0; 259 } 260 261 262 if (val) { 263 *ret_page = pfn_to_page(__phys_to_pfn(phys)); 264 ptr = (void *)val; 265 memset(ptr, 0, size); 266 267 if (gen_pool_avail(pool) < atomic_pool_size) 268 schedule_work(&atomic_pool_work); 269 } 270 271 return ptr; 272 } 273 274 bool dma_free_from_pool(struct device *dev, void *start, size_t size) 275 { 276 struct gen_pool *pool = NULL; 277 278 while (1) { 279 pool = dma_guess_pool(dev, pool); 280 if (!pool) 281 return false; 282 283 if (gen_pool_has_addr(pool, (unsigned long)start, size)) { 284 gen_pool_free(pool, (unsigned long)start, size); 285 return true; 286 } 287 } 288 } 289