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         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_ORDER-1 */
  88         order = min(get_order(pool_size), MAX_ORDER-1);
  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 #endif
 139 free_page: __maybe_unused
 140         __free_pages(page, order);
 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_ORDER-1.
 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 (IS_ENABLED(CONFIG_ZONE_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 (IS_ENABLED(CONFIG_ZONE_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 }