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 debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma); 42 debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32); 43 debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel); 44 } 45 46 static void dma_atomic_pool_size_add(gfp_t gfp, size_t size) 47 { 48 if (gfp & __GFP_DMA) 49 pool_size_dma += size; 50 else if (gfp & __GFP_DMA32) 51 pool_size_dma32 += size; 52 else 53 pool_size_kernel += size; 54 } 55 56 static bool cma_in_zone(gfp_t gfp) 57 { 58 unsigned long size; 59 phys_addr_t end; 60 struct cma *cma; 61 62 cma = dev_get_cma_area(NULL); 63 if (!cma) 64 return false; 65 66 size = cma_get_size(cma); 67 if (!size) 68 return false; 69 70 /* CMA can't cross zone boundaries, see cma_activate_area() */ 71 end = cma_get_base(cma) + size - 1; 72 if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA)) 73 return end <= DMA_BIT_MASK(zone_dma_bits); 74 if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32)) 75 return end <= DMA_BIT_MASK(32); 76 return true; 77 } 78 79 static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, 80 gfp_t gfp) 81 { 82 unsigned int order; 83 struct page *page = NULL; 84 void *addr; 85 int ret = -ENOMEM; 86 87 /* Cannot allocate larger than MAX_PAGE_ORDER */ 88 order = min(get_order(pool_size), MAX_PAGE_ORDER); 89 90 do { 91 pool_size = 1 << (PAGE_SHIFT + order); 92 if (cma_in_zone(gfp)) 93 page = dma_alloc_from_contiguous(NULL, 1 << order, 94 order, false); 95 if (!page) 96 page = alloc_pages(gfp, order); 97 } while (!page && order-- > 0); 98 if (!page) 99 goto out; 100 101 arch_dma_prep_coherent(page, pool_size); 102 103 #ifdef CONFIG_DMA_DIRECT_REMAP 104 addr = dma_common_contiguous_remap(page, pool_size, 105 pgprot_dmacoherent(PAGE_KERNEL), 106 __builtin_return_address(0)); 107 if (!addr) 108 goto free_page; 109 #else 110 addr = page_to_virt(page); 111 #endif 112 /* 113 * Memory in the atomic DMA pools must be unencrypted, the pools do not 114 * shrink so no re-encryption occurs in dma_direct_free(). 115 */ 116 ret = set_memory_decrypted((unsigned long)page_to_virt(page), 117 1 << order); 118 if (ret) 119 goto remove_mapping; 120 ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), 121 pool_size, NUMA_NO_NODE); 122 if (ret) 123 goto encrypt_mapping; 124 125 dma_atomic_pool_size_add(gfp, pool_size); 126 return 0; 127 128 encrypt_mapping: 129 ret = set_memory_encrypted((unsigned long)page_to_virt(page), 130 1 << order); 131 if (WARN_ON_ONCE(ret)) { 132 /* Decrypt succeeded but encrypt failed, purposely leak */ 133 goto out; 134 } 135 remove_mapping: 136 #ifdef CONFIG_DMA_DIRECT_REMAP 137 dma_common_free_remap(addr, pool_size); 138 free_page: 139 __free_pages(page, order); 140 #endif 141 out: 142 return ret; 143 } 144 145 static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp) 146 { 147 if (pool && gen_pool_avail(pool) < atomic_pool_size) 148 atomic_pool_expand(pool, gen_pool_size(pool), gfp); 149 } 150 151 static void atomic_pool_work_fn(struct work_struct *work) 152 { 153 if (IS_ENABLED(CONFIG_ZONE_DMA)) 154 atomic_pool_resize(atomic_pool_dma, 155 GFP_KERNEL | GFP_DMA); 156 if (IS_ENABLED(CONFIG_ZONE_DMA32)) 157 atomic_pool_resize(atomic_pool_dma32, 158 GFP_KERNEL | GFP_DMA32); 159 atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL); 160 } 161 162 static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size, 163 gfp_t gfp) 164 { 165 struct gen_pool *pool; 166 int ret; 167 168 pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE); 169 if (!pool) 170 return NULL; 171 172 gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL); 173 174 ret = atomic_pool_expand(pool, pool_size, gfp); 175 if (ret) { 176 gen_pool_destroy(pool); 177 pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n", 178 pool_size >> 10, &gfp); 179 return NULL; 180 } 181 182 pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n", 183 gen_pool_size(pool) >> 10, &gfp); 184 return pool; 185 } 186 187 static int __init dma_atomic_pool_init(void) 188 { 189 int ret = 0; 190 191 /* 192 * If coherent_pool was not used on the command line, default the pool 193 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_PAGE_ORDER. 194 */ 195 if (!atomic_pool_size) { 196 unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K); 197 pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES); 198 atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K); 199 } 200 INIT_WORK(&atomic_pool_work, atomic_pool_work_fn); 201 202 atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size, 203 GFP_KERNEL); 204 if (!atomic_pool_kernel) 205 ret = -ENOMEM; 206 if (has_managed_dma()) { 207 atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size, 208 GFP_KERNEL | GFP_DMA); 209 if (!atomic_pool_dma) 210 ret = -ENOMEM; 211 } 212 if (IS_ENABLED(CONFIG_ZONE_DMA32)) { 213 atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size, 214 GFP_KERNEL | GFP_DMA32); 215 if (!atomic_pool_dma32) 216 ret = -ENOMEM; 217 } 218 219 dma_atomic_pool_debugfs_init(); 220 return ret; 221 } 222 postcore_initcall(dma_atomic_pool_init); 223 224 static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp) 225 { 226 if (prev == NULL) { 227 if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32)) 228 return atomic_pool_dma32; 229 if (atomic_pool_dma && (gfp & GFP_DMA)) 230 return atomic_pool_dma; 231 return atomic_pool_kernel; 232 } 233 if (prev == atomic_pool_kernel) 234 return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma; 235 if (prev == atomic_pool_dma32) 236 return atomic_pool_dma; 237 return NULL; 238 } 239 240 static struct page *__dma_alloc_from_pool(struct device *dev, size_t size, 241 struct gen_pool *pool, void **cpu_addr, 242 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t)) 243 { 244 unsigned long addr; 245 phys_addr_t phys; 246 247 addr = gen_pool_alloc(pool, size); 248 if (!addr) 249 return NULL; 250 251 phys = gen_pool_virt_to_phys(pool, addr); 252 if (phys_addr_ok && !phys_addr_ok(dev, phys, size)) { 253 gen_pool_free(pool, addr, size); 254 return NULL; 255 } 256 257 if (gen_pool_avail(pool) < atomic_pool_size) 258 schedule_work(&atomic_pool_work); 259 260 *cpu_addr = (void *)addr; 261 memset(*cpu_addr, 0, size); 262 return pfn_to_page(__phys_to_pfn(phys)); 263 } 264 265 struct page *dma_alloc_from_pool(struct device *dev, size_t size, 266 void **cpu_addr, gfp_t gfp, 267 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t)) 268 { 269 struct gen_pool *pool = NULL; 270 struct page *page; 271 272 while ((pool = dma_guess_pool(pool, gfp))) { 273 page = __dma_alloc_from_pool(dev, size, pool, cpu_addr, 274 phys_addr_ok); 275 if (page) 276 return page; 277 } 278 279 WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev)); 280 return NULL; 281 } 282 283 bool dma_free_from_pool(struct device *dev, void *start, size_t size) 284 { 285 struct gen_pool *pool = NULL; 286 287 while ((pool = dma_guess_pool(pool, 0))) { 288 if (!gen_pool_has_addr(pool, (unsigned long)start, size)) 289 continue; 290 gen_pool_free(pool, (unsigned long)start, size); 291 return true; 292 } 293 294 return false; 295 } 296