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-contiguous.h>
   9 #include <linux/dma-direct.h>
  10 #include <linux/dma-noncoherent.h>
  11 #include <linux/init.h>
  12 #include <linux/genalloc.h>
  13 #include <linux/set_memory.h>
  14 #include <linux/slab.h>
  15 #include <linux/workqueue.h>
  16
  17 static struct gen_pool *atomic_pool_dma __ro_after_init;
  18 static unsigned long pool_size_dma;
  19 static struct gen_pool *atomic_pool_dma32 __ro_after_init;
  20 static unsigned long pool_size_dma32;
  21 static struct gen_pool *atomic_pool_kernel __ro_after_init;
  22 static unsigned long pool_size_kernel;
  23
  24 /* Size can be defined by the coherent_pool command line */
  25 static size_t atomic_pool_size;
  26
  27 /* Dynamic background expansion when the atomic pool is near capacity */
  28 static struct work_struct atomic_pool_work;
  29
  30 static int __init early_coherent_pool(char *p)
  31 {
  32         atomic_pool_size = memparse(p, &p);
  33         return 0;
  34 }
  35 early_param("coherent_pool", early_coherent_pool);
  36
  37 static void __init dma_atomic_pool_debugfs_init(void)
  38 {
  39         struct dentry *root;
  40
  41         root = debugfs_create_dir("dma_pools", NULL);
  42         if (IS_ERR_OR_NULL(root))
  43                 return;
  44
  45         debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
  46         debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
  47         debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
  48 }
  49
  50 static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
  51 {
  52         if (gfp & __GFP_DMA)
  53                 pool_size_dma += size;
  54         else if (gfp & __GFP_DMA32)
  55                 pool_size_dma32 += size;
  56         else
  57                 pool_size_kernel += size;
  58 }
  59
  60 static bool cma_in_zone(gfp_t gfp)
  61 {
  62         unsigned long size;
  63         phys_addr_t end;
  64         struct cma *cma;
  65
  66         cma = dev_get_cma_area(NULL);
  67         if (!cma)
  68                 return false;
  69
  70         size = cma_get_size(cma);
  71         if (!size)
  72                 return false;
  73
  74         /* CMA can't cross zone boundaries, see cma_activate_area() */
  75         end = cma_get_base(cma) + size - 1;
  76         if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA))
  77                 return end <= DMA_BIT_MASK(zone_dma_bits);
  78         if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
  79                 return end <= DMA_BIT_MASK(32);
  80         return true;
  81 }
  82
  83 static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
  84                               gfp_t gfp)
  85 {
  86         unsigned int order;
  87         struct page *page = NULL;
  88         void *addr;
  89         int ret = -ENOMEM;
  90
  91         /* Cannot allocate larger than MAX_ORDER-1 */
  92         order = min(get_order(pool_size), MAX_ORDER-1);
  93
  94         do {
  95                 pool_size = 1 << (PAGE_SHIFT + order);
  96                 if (cma_in_zone(gfp))
  97                         page = dma_alloc_from_contiguous(NULL, 1 << order,
  98                                                          order, false);
  99                 if (!page)
 100                         page = alloc_pages(gfp, order);
 101         } while (!page && order-- > 0);
 102         if (!page)
 103                 goto out;
 104
 105         arch_dma_prep_coherent(page, pool_size);
 106
 107 #ifdef CONFIG_DMA_DIRECT_REMAP
 108         addr = dma_common_contiguous_remap(page, pool_size,
 109                                            pgprot_dmacoherent(PAGE_KERNEL),
 110                                            __builtin_return_address(0));
 111         if (!addr)
 112                 goto free_page;
 113 #else
 114         addr = page_to_virt(page);
 115 #endif
 116         /*
 117          * Memory in the atomic DMA pools must be unencrypted, the pools do not
 118          * shrink so no re-encryption occurs in dma_direct_free_pages().
 119          */
 120         ret = set_memory_decrypted((unsigned long)page_to_virt(page),
 121                                    1 << order);
 122         if (ret)
 123                 goto remove_mapping;
 124         ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page),
 125                                 pool_size, NUMA_NO_NODE);
 126         if (ret)
 127                 goto encrypt_mapping;
 128
 129         dma_atomic_pool_size_add(gfp, pool_size);
 130         return 0;
 131
 132 encrypt_mapping:
 133         ret = set_memory_encrypted((unsigned long)page_to_virt(page),
 134                                    1 << order);
 135         if (WARN_ON_ONCE(ret)) {
 136                 /* Decrypt succeeded but encrypt failed, purposely leak */
 137                 goto out;
 138         }
 139 remove_mapping:
 140 #ifdef CONFIG_DMA_DIRECT_REMAP
 141         dma_common_free_remap(addr, pool_size);
 142 #endif
 143 free_page: __maybe_unused
 144         __free_pages(page, order);
 145 out:
 146         return ret;
 147 }
 148
 149 static void atomic_pool_resize(struct gen_pool *pool, gfp_t gfp)
 150 {
 151         if (pool && gen_pool_avail(pool) < atomic_pool_size)
 152                 atomic_pool_expand(pool, gen_pool_size(pool), gfp);
 153 }
 154
 155 static void atomic_pool_work_fn(struct work_struct *work)
 156 {
 157         if (IS_ENABLED(CONFIG_ZONE_DMA))
 158                 atomic_pool_resize(atomic_pool_dma,
 159                                    GFP_KERNEL | GFP_DMA);
 160         if (IS_ENABLED(CONFIG_ZONE_DMA32))
 161                 atomic_pool_resize(atomic_pool_dma32,
 162                                    GFP_KERNEL | GFP_DMA32);
 163         atomic_pool_resize(atomic_pool_kernel, GFP_KERNEL);
 164 }
 165
 166 static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
 167                                                       gfp_t gfp)
 168 {
 169         struct gen_pool *pool;
 170         int ret;
 171
 172         pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
 173         if (!pool)
 174                 return NULL;
 175
 176         gen_pool_set_algo(pool, gen_pool_first_fit_order_align, NULL);
 177
 178         ret = atomic_pool_expand(pool, pool_size, gfp);
 179         if (ret) {
 180                 gen_pool_destroy(pool);
 181                 pr_err("DMA: failed to allocate %zu KiB %pGg pool for atomic allocation\n",
 182                        pool_size >> 10, &gfp);
 183                 return NULL;
 184         }
 185
 186         pr_info("DMA: preallocated %zu KiB %pGg pool for atomic allocations\n",
 187                 gen_pool_size(pool) >> 10, &gfp);
 188         return pool;
 189 }
 190
 191 static int __init dma_atomic_pool_init(void)
 192 {
 193         int ret = 0;
 194
 195         /*
 196          * If coherent_pool was not used on the command line, default the pool
 197          * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
 198          */
 199         if (!atomic_pool_size) {
 200                 unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
 201                 pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
 202                 atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
 203         }
 204         INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);
 205
 206         atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
 207                                                     GFP_KERNEL);
 208         if (!atomic_pool_kernel)
 209                 ret = -ENOMEM;
 210         if (IS_ENABLED(CONFIG_ZONE_DMA)) {
 211                 atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size,
 212                                                 GFP_KERNEL | GFP_DMA);
 213                 if (!atomic_pool_dma)
 214                         ret = -ENOMEM;
 215         }
 216         if (IS_ENABLED(CONFIG_ZONE_DMA32)) {
 217                 atomic_pool_dma32 = __dma_atomic_pool_init(atomic_pool_size,
 218                                                 GFP_KERNEL | GFP_DMA32);
 219                 if (!atomic_pool_dma32)
 220                         ret = -ENOMEM;
 221         }
 222
 223         dma_atomic_pool_debugfs_init();
 224         return ret;
 225 }
 226 postcore_initcall(dma_atomic_pool_init);
 227
 228 static inline struct gen_pool *dma_guess_pool(struct gen_pool *prev, gfp_t gfp)
 229 {
 230         if (prev == NULL) {
 231                 if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32))
 232                         return atomic_pool_dma32;
 233                 if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA))
 234                         return atomic_pool_dma;
 235                 return atomic_pool_kernel;
 236         }
 237         if (prev == atomic_pool_kernel)
 238                 return atomic_pool_dma32 ? atomic_pool_dma32 : atomic_pool_dma;
 239         if (prev == atomic_pool_dma32)
 240                 return atomic_pool_dma;
 241         return NULL;
 242 }
 243
 244 static struct page *__dma_alloc_from_pool(struct device *dev, size_t size,
 245                 struct gen_pool *pool, void **cpu_addr,
 246                 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
 247 {
 248         unsigned long addr;
 249         phys_addr_t phys;
 250
 251         addr = gen_pool_alloc(pool, size);
 252         if (!addr)
 253                 return NULL;
 254
 255         phys = gen_pool_virt_to_phys(pool, addr);
 256         if (phys_addr_ok && !phys_addr_ok(dev, phys, size)) {
 257                 gen_pool_free(pool, addr, size);
 258                 return NULL;
 259         }
 260
 261         if (gen_pool_avail(pool) < atomic_pool_size)
 262                 schedule_work(&atomic_pool_work);
 263
 264         *cpu_addr = (void *)addr;
 265         memset(*cpu_addr, 0, size);
 266         return pfn_to_page(__phys_to_pfn(phys));
 267 }
 268
 269 struct page *dma_alloc_from_pool(struct device *dev, size_t size,
 270                 void **cpu_addr, gfp_t gfp,
 271                 bool (*phys_addr_ok)(struct device *, phys_addr_t, size_t))
 272 {
 273         struct gen_pool *pool = NULL;
 274         struct page *page;
 275
 276         while ((pool = dma_guess_pool(pool, gfp))) {
 277                 page = __dma_alloc_from_pool(dev, size, pool, cpu_addr,
 278                                              phys_addr_ok);
 279                 if (page)
 280                         return page;
 281         }
 282
 283         WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));
 284         return NULL;
 285 }
 286
 287 bool dma_free_from_pool(struct device *dev, void *start, size_t size)
 288 {
 289         struct gen_pool *pool = NULL;
 290
 291         while ((pool = dma_guess_pool(pool, 0))) {
 292                 if (!gen_pool_has_addr(pool, (unsigned long)start, size))
 293                         continue;
 294                 gen_pool_free(pool, (unsigned long)start, size);
 295                 return true;
 296         }
 297
 298         return false;
 299 }