1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2012 ARM Ltd. 4 * Copyright (C) 2020 Google LLC 5 */ 6 #include <linux/cma.h> 7 #include <linux/debugfs.h> 8 #include <linux/dma-map-ops.h> 9 #include <linux/dma-direct.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 bool cma_in_zone(gfp_t gfp) 60 { 61 unsigned long size; 62 phys_addr_t end; 63 struct cma *cma; 64 65 cma = dev_get_cma_area(NULL); 66 if (!cma) 67 return false; 68 69 size = cma_get_size(cma); 70 if (!size) 71 return false; 72 73 /* CMA can't cross zone boundaries, see cma_activate_area() */ 74 end = cma_get_base(cma) + size - 1; 75 if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA)) 76 return end <= DMA_BIT_MASK(zone_dma_bits); 77 if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32)) 78 return end <= DMA_BIT_MASK(32); 79 return true; 80 } 81 82 static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, 83 gfp_t gfp) 84 { 85 unsigned int order; 86 struct page *page = NULL; 87 void *addr; 88 int ret = -ENOMEM; 89 90 /* Cannot allocate larger than MAX_ORDER-1 */ 91 order = min(get_order(pool_size), MAX_ORDER-1); 92 93 do { 94 pool_size = 1 << (PAGE_SHIFT + order); 95 if (cma_in_zone(gfp)) 96 page = dma_alloc_from_contiguous(NULL, 1 << order, 97 order, false); 98 if (!page) 99 page = alloc_pages(gfp, order); 100 } while (!page && order-- > 0); 101 if (!page) 102 goto out; 103 104 arch_dma_prep_coherent(page, pool_size); 105 106 #ifdef CONFIG_DMA_DIRECT_REMAP 107 addr = dma_common_contiguous_remap(page, pool_size, 108 pgprot_dmacoherent(PAGE_KERNEL), 109 __builtin_return_address(0)); 110 if (!addr) 111 goto free_page; 112 #else 113 addr = page_to_virt(page); 114 #endif 115 /* 116 * Memory in the atomic DMA pools must be unencrypted, the pools do not 117 * shrink so no re-encryption occurs in dma_direct_free(). 118 */ 119 ret = set_memory_decrypted((unsigned long)page_to_virt(page), 120 1 << order); 121 if (ret) 122 goto remove_mapping; 123 ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), 124 pool_size, NUMA_NO_NODE); 125 if (ret) 126 goto encrypt_mapping; 127 128 dma_atomic_pool_size_add(gfp, pool_size); 129 return 0; 130 131 encrypt_mapping: 132 ret = set_memory_encrypted((unsigned long)page_to_virt(page), 133 1 << order); 134 if (WARN_ON_ONCE(ret)) { 135 /* Decrypt succeeded but encrypt failed, purposely leak */ 136 goto out; 137 } 138 remove_mapping: 139 #ifdef CONFIG_DMA_DIRECT_REMAP 140 dma_common_free_remap(addr, pool_size); 141 #endif 142 free_page: __maybe_unused 143 __free_pages(page, order); 144 out: 145 return ret; 146 } 147 148 static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp) 149 { 150 if (pool && gen_pool_avail(pool) < atomic_pool_size) 151 atomic_pool_expand(pool, gen_pool_size(pool), gfp); 152 } 153 154 static void atomic_pool_work_fn(struct work_struct *work) 155 { 156 if (IS_ENABLED(CONFIG_ZONE_DMA)) 157 atomic_pool_resize(atomic_pool_dma, 158 GFP_KERNEL | GFP_DMA); 159 if (IS_ENABLED(CONFIG_ZONE_DMA32)) 160 atomic_pool_resize(atomic_pool_dma32, 161 GFP_KERNEL | GFP_DMA32); 162 atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL); 163 } 164 165 static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size, 166 gfp_t gfp) 167 { 168 struct gen_pool *pool; 169 int ret; 170 171 pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); 172 if (!pool) 173 return NULL; 174 175 gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL); 176 177 ret = atomic_pool_expand(pool, pool_size, gfp); 178 if (ret) { 179 gen_pool_destroy(pool); 180 pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n", 181 pool_size >> 10, &gfp); 182 return NULL; 183 } 184 185 pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n", 186 gen_pool_size(pool) >> 10, &gfp); 187 return pool; 188 } 189 190 static int __init dma_atomic_pool_init(void) 191 { 192 int ret = 0; 193 194 /* 195 * If coherent_pool was not used on the command line, default the pool 196 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1. 197 */ 198 if (!atomic_pool_size) { 199 unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K); 200 pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES); 201 atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K); 202 } 203 INIT_WORK(&atomic_pool_work, atomic_pool_work_fn); 204 205 atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size, 206 GFP_KERNEL); 207 if (!atomic_pool_kernel) 208 ret = -ENOMEM; 209 if (IS_ENABLED(CONFIG_ZONE_DMA)) { 210 atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size, 211 GFP_KERNEL | GFP_DMA); 212 if (!atomic_pool_dma) 213 ret = -ENOMEM; 214 } 215 if (IS_ENABLED(CONFIG_ZONE_DMA32)) { 216 atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size, 217 GFP_KERNEL | GFP_DMA32); 218 if (!atomic_pool_dma32) 219 ret = -ENOMEM; 220 } 221 222 dma_atomic_pool_debugfs_init(); 223 return ret; 224 } 225 postcore_initcall(dma_atomic_pool_init); 226 227 static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp) 228 { 229 if (prev == NULL) { 230 if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32)) 231 return atomic_pool_dma32; 232 if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA)) 233 return atomic_pool_dma; 234 return atomic_pool_kernel; 235 } 236 if (prev == atomic_pool_kernel) 237 return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma; 238 if (prev == atomic_pool_dma32) 239 return atomic_pool_dma; 240 return NULL; 241 } 242 243 static struct page *__dma_alloc_from_pool(struct device *dev, size_t size, 244 struct gen_pool *pool, void **cpu_addr, 245 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t)) 246 { 247 unsigned long addr; 248 phys_addr_t phys; 249 250 addr = gen_pool_alloc(pool, size); 251 if (!addr) 252 return NULL; 253 254 phys = gen_pool_virt_to_phys(pool, addr); 255 if (phys_addr_ok && !phys_addr_ok(dev, phys, size)) { 256 gen_pool_free(pool, addr, size); 257 return NULL; 258 } 259 260 if (gen_pool_avail(pool) < atomic_pool_size) 261 schedule_work(&atomic_pool_work); 262 263 *cpu_addr = (void *)addr; 264 memset(*cpu_addr, 0, size); 265 return pfn_to_page(__phys_to_pfn(phys)); 266 } 267 268 struct page *dma_alloc_from_pool(struct device *dev, size_t size, 269 void **cpu_addr, gfp_t gfp, 270 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t)) 271 { 272 struct gen_pool *pool = NULL; 273 struct page *page; 274 275 while ((pool = dma_guess_pool(pool, gfp))) { 276 page = __dma_alloc_from_pool(dev, size, pool, cpu_addr, 277 phys_addr_ok); 278 if (page) 279 return page; 280 } 281 282 WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev)); 283 return NULL; 284 } 285 286 bool dma_free_from_pool(struct device *dev, void *start, size_t size) 287 { 288 struct gen_pool *pool = NULL; 289 290 while ((pool = dma_guess_pool(pool, 0))) { 291 if (!gen_pool_has_addr(pool, (unsigned long)start, size)) 292 continue; 293 gen_pool_free(pool, (unsigned long)start, size); 294 return true; 295 } 296 297 return false; 298 } 299