kernel/dma/pool.c

   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 }