kernel/dma/direct.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2018-2020 Christoph Hellwig.
   4  *
   5  * DMA operations that map physical memory directly without using an IOMMU.
   6  */
   7 #include <linux/memblock.h> /* for max_pfn */
   8 #include <linux/export.h>
   9 #include <linux/mm.h>
  10 #include <linux/dma-map-ops.h>
  11 #include <linux/scatterlist.h>
  12 #include <linux/pfn.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/set_memory.h>
  15 #include <linux/slab.h>
  16 #include "direct.h"
  17
  18 /*
  19  * Most architectures use ZONE_DMA for the first 16 Megabytes, but some use
  20  * it for entirely different regions. In that case the arch code needs to
  21  * override the variable below for dma-direct to work properly.
  22  */
  23 unsigned int zone_dma_bits __ro_after_init = 24;
  24
  25 static inline dma_addr_t phys_to_dma_direct(struct device *dev,
  26                 phys_addr_t phys)
  27 {
  28         if (force_dma_unencrypted(dev))
  29                 return phys_to_dma_unencrypted(dev, phys);
  30         return phys_to_dma(dev, phys);
  31 }
  32
  33 static inline struct page *dma_direct_to_page(struct device *dev,
  34                 dma_addr_t dma_addr)
  35 {
  36         return pfn_to_page(PHYS_PFN(dma_to_phys(dev, dma_addr)));
  37 }
  38
  39 u64 dma_direct_get_required_mask(struct device *dev)
  40 {
  41         phys_addr_t phys = (phys_addr_t)(max_pfn - 1) << PAGE_SHIFT;
  42         u64 max_dma = phys_to_dma_direct(dev, phys);
  43
  44         return (1ULL << (fls64(max_dma) - 1)) * 2 - 1;
  45 }
  46
  47 static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
  48                                   u64 *phys_limit)
  49 {
  50         u64 dma_limit = min_not_zero(dma_mask, dev->bus_dma_limit);
  51
  52         /*
  53          * Optimistically try the zone that the physical address mask falls
  54          * into first.  If that returns memory that isn't actually addressable
  55          * we will fallback to the next lower zone and try again.
  56          *
  57          * Note that GFP_DMA32 and GFP_DMA are no ops without the corresponding
  58          * zones.
  59          */
  60         *phys_limit = dma_to_phys(dev, dma_limit);
  61         if (*phys_limit <= DMA_BIT_MASK(zone_dma_bits))
  62                 return GFP_DMA;
  63         if (*phys_limit <= DMA_BIT_MASK(32))
  64                 return GFP_DMA32;
  65         return 0;
  66 }
  67
  68 static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size)
  69 {
  70         dma_addr_t dma_addr = phys_to_dma_direct(dev, phys);
  71
  72         if (dma_addr == DMA_MAPPING_ERROR)
  73                 return false;
  74         return dma_addr + size - 1 <=
  75                 min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit);
  76 }
  77
  78 static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size,
  79                 gfp_t gfp)
  80 {
  81         int node = dev_to_node(dev);
  82         struct page *page = NULL;
  83         u64 phys_limit;
  84
  85         WARN_ON_ONCE(!PAGE_ALIGNED(size));
  86
  87         gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
  88                                            &phys_limit);
  89         page = dma_alloc_contiguous(dev, size, gfp);
  90         if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
  91                 dma_free_contiguous(dev, page, size);
  92                 page = NULL;
  93         }
  94 again:
  95         if (!page)
  96                 page = alloc_pages_node(node, gfp, get_order(size));
  97         if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) {
  98                 dma_free_contiguous(dev, page, size);
  99                 page = NULL;
 100
 101                 if (IS_ENABLED(CONFIG_ZONE_DMA32) &&
 102                     phys_limit < DMA_BIT_MASK(64) &&
 103                     !(gfp & (GFP_DMA32 | GFP_DMA))) {
 104                         gfp |= GFP_DMA32;
 105                         goto again;
 106                 }
 107
 108                 if (IS_ENABLED(CONFIG_ZONE_DMA) && !(gfp & GFP_DMA)) {
 109                         gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
 110                         goto again;
 111                 }
 112         }
 113
 114         return page;
 115 }
 116
 117 static void *dma_direct_alloc_from_pool(struct device *dev, size_t size,
 118                 dma_addr_t *dma_handle, gfp_t gfp)
 119 {
 120         struct page *page;
 121         u64 phys_mask;
 122         void *ret;
 123
 124         gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask,
 125                                            &phys_mask);
 126         page = dma_alloc_from_pool(dev, size, &ret, gfp, dma_coherent_ok);
 127         if (!page)
 128                 return NULL;
 129         *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
 130         return ret;
 131 }
 132
 133 void *dma_direct_alloc(struct device *dev, size_t size,
 134                 dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 135 {
 136         struct page *page;
 137         void *ret;
 138         int err;
 139
 140         size = PAGE_ALIGN(size);
 141         if (attrs & DMA_ATTR_NO_WARN)
 142                 gfp |= __GFP_NOWARN;
 143
 144         if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
 145             !force_dma_unencrypted(dev)) {
 146                 page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
 147                 if (!page)
 148                         return NULL;
 149                 /* remove any dirty cache lines on the kernel alias */
 150                 if (!PageHighMem(page))
 151                         arch_dma_prep_coherent(page, size);
 152                 *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
 153                 /* return the page pointer as the opaque cookie */
 154                 return page;
 155         }
 156
 157         if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
 158             !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
 159             !dev_is_dma_coherent(dev))
 160                 return arch_dma_alloc(dev, size, dma_handle, gfp, attrs);
 161
 162         /*
 163          * Remapping or decrypting memory may block. If either is required and
 164          * we can't block, allocate the memory from the atomic pools.
 165          */
 166         if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
 167             !gfpflags_allow_blocking(gfp) &&
 168             (force_dma_unencrypted(dev) ||
 169              (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev))))
 170                 return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 171
 172         /* we always manually zero the memory once we are done */
 173         page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO);
 174         if (!page)
 175                 return NULL;
 176
 177         if ((IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
 178              !dev_is_dma_coherent(dev)) ||
 179             (IS_ENABLED(CONFIG_DMA_REMAP) && PageHighMem(page))) {
 180                 /* remove any dirty cache lines on the kernel alias */
 181                 arch_dma_prep_coherent(page, size);
 182
 183                 /* create a coherent mapping */
 184                 ret = dma_common_contiguous_remap(page, size,
 185                                 dma_pgprot(dev, PAGE_KERNEL, attrs),
 186                                 __builtin_return_address(0));
 187                 if (!ret)
 188                         goto out_free_pages;
 189                 if (force_dma_unencrypted(dev)) {
 190                         err = set_memory_decrypted((unsigned long)ret,
 191                                                    1 << get_order(size));
 192                         if (err)
 193                                 goto out_free_pages;
 194                 }
 195                 memset(ret, 0, size);
 196                 goto done;
 197         }
 198
 199         if (PageHighMem(page)) {
 200                 /*
 201                  * Depending on the cma= arguments and per-arch setup
 202                  * dma_alloc_contiguous could return highmem pages.
 203                  * Without remapping there is no way to return them here,
 204                  * so log an error and fail.
 205                  */
 206                 dev_info(dev, "Rejecting highmem page from CMA.\n");
 207                 goto out_free_pages;
 208         }
 209
 210         ret = page_address(page);
 211         if (force_dma_unencrypted(dev)) {
 212                 err = set_memory_decrypted((unsigned long)ret,
 213                                            1 << get_order(size));
 214                 if (err)
 215                         goto out_free_pages;
 216         }
 217
 218         memset(ret, 0, size);
 219
 220         if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
 221             !dev_is_dma_coherent(dev)) {
 222                 arch_dma_prep_coherent(page, size);
 223                 ret = arch_dma_set_uncached(ret, size);
 224                 if (IS_ERR(ret))
 225                         goto out_encrypt_pages;
 226         }
 227 done:
 228         *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
 229         return ret;
 230
 231 out_encrypt_pages:
 232         if (force_dma_unencrypted(dev)) {
 233                 err = set_memory_encrypted((unsigned long)page_address(page),
 234                                            1 << get_order(size));
 235                 /* If memory cannot be re-encrypted, it must be leaked */
 236                 if (err)
 237                         return NULL;
 238         }
 239 out_free_pages:
 240         dma_free_contiguous(dev, page, size);
 241         return NULL;
 242 }
 243
 244 void dma_direct_free(struct device *dev, size_t size,
 245                 void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs)
 246 {
 247         unsigned int page_order = get_order(size);
 248
 249         if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
 250             !force_dma_unencrypted(dev)) {
 251                 /* cpu_addr is a struct page cookie, not a kernel address */
 252                 dma_free_contiguous(dev, cpu_addr, size);
 253                 return;
 254         }
 255
 256         if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) &&
 257             !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) &&
 258             !dev_is_dma_coherent(dev)) {
 259                 arch_dma_free(dev, size, cpu_addr, dma_addr, attrs);
 260                 return;
 261         }
 262
 263         /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
 264         if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
 265             dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size)))
 266                 return;
 267
 268         if (force_dma_unencrypted(dev))
 269                 set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order);
 270
 271         if (IS_ENABLED(CONFIG_DMA_REMAP) && is_vmalloc_addr(cpu_addr))
 272                 vunmap(cpu_addr);
 273         else if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED))
 274                 arch_dma_clear_uncached(cpu_addr, size);
 275
 276         dma_free_contiguous(dev, dma_direct_to_page(dev, dma_addr), size);
 277 }
 278
 279 struct page *dma_direct_alloc_pages(struct device *dev, size_t size,
 280                 dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp)
 281 {
 282         struct page *page;
 283         void *ret;
 284
 285         if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
 286             force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp))
 287                 return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp);
 288
 289         page = __dma_direct_alloc_pages(dev, size, gfp);
 290         if (!page)
 291                 return NULL;
 292         if (PageHighMem(page)) {
 293                 /*
 294                  * Depending on the cma= arguments and per-arch setup
 295                  * dma_alloc_contiguous could return highmem pages.
 296                  * Without remapping there is no way to return them here,
 297                  * so log an error and fail.
 298                  */
 299                 dev_info(dev, "Rejecting highmem page from CMA.\n");
 300                 goto out_free_pages;
 301         }
 302
 303         ret = page_address(page);
 304         if (force_dma_unencrypted(dev)) {
 305                 if (set_memory_decrypted((unsigned long)ret,
 306                                 1 << get_order(size)))
 307                         goto out_free_pages;
 308         }
 309         memset(ret, 0, size);
 310         *dma_handle = phys_to_dma_direct(dev, page_to_phys(page));
 311         return page;
 312 out_free_pages:
 313         dma_free_contiguous(dev, page, size);
 314         return NULL;
 315 }
 316
 317 void dma_direct_free_pages(struct device *dev, size_t size,
 318                 struct page *page, dma_addr_t dma_addr,
 319                 enum dma_data_direction dir)
 320 {
 321         unsigned int page_order = get_order(size);
 322         void *vaddr = page_address(page);
 323
 324         /* If cpu_addr is not from an atomic pool, dma_free_from_pool() fails */
 325         if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) &&
 326             dma_free_from_pool(dev, vaddr, size))
 327                 return;
 328
 329         if (force_dma_unencrypted(dev))
 330                 set_memory_encrypted((unsigned long)vaddr, 1 << page_order);
 331
 332         dma_free_contiguous(dev, page, size);
 333 }
 334
 335 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \
 336     defined(CONFIG_SWIOTLB)
 337 void dma_direct_sync_sg_for_device(struct device *dev,
 338                 struct scatterlist *sgl, int nents, enum dma_data_direction dir)
 339 {
 340         struct scatterlist *sg;
 341         int i;
 342
 343         for_each_sg(sgl, sg, nents, i) {
 344                 phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
 345
 346                 if (unlikely(is_swiotlb_buffer(paddr)))
 347                         swiotlb_tbl_sync_single(dev, paddr, sg->length,
 348                                         dir, SYNC_FOR_DEVICE);
 349
 350                 if (!dev_is_dma_coherent(dev))
 351                         arch_sync_dma_for_device(paddr, sg->length,
 352                                         dir);
 353         }
 354 }
 355 #endif
 356
 357 #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU) || \
 358     defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL) || \
 359     defined(CONFIG_SWIOTLB)
 360 void dma_direct_sync_sg_for_cpu(struct device *dev,
 361                 struct scatterlist *sgl, int nents, enum dma_data_direction dir)
 362 {
 363         struct scatterlist *sg;
 364         int i;
 365
 366         for_each_sg(sgl, sg, nents, i) {
 367                 phys_addr_t paddr = dma_to_phys(dev, sg_dma_address(sg));
 368
 369                 if (!dev_is_dma_coherent(dev))
 370                         arch_sync_dma_for_cpu(paddr, sg->length, dir);
 371
 372                 if (unlikely(is_swiotlb_buffer(paddr)))
 373                         swiotlb_tbl_sync_single(dev, paddr, sg->length, dir,
 374                                         SYNC_FOR_CPU);
 375
 376                 if (dir == DMA_FROM_DEVICE)
 377                         arch_dma_mark_clean(paddr, sg->length);
 378         }
 379
 380         if (!dev_is_dma_coherent(dev))
 381                 arch_sync_dma_for_cpu_all();
 382 }
 383
 384 void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
 385                 int nents, enum dma_data_direction dir, unsigned long attrs)
 386 {
 387         struct scatterlist *sg;
 388         int i;
 389
 390         for_each_sg(sgl, sg, nents, i)
 391                 dma_direct_unmap_page(dev, sg->dma_address, sg_dma_len(sg), dir,
 392                              attrs);
 393 }
 394 #endif
 395
 396 int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
 397                 enum dma_data_direction dir, unsigned long attrs)
 398 {
 399         int i;
 400         struct scatterlist *sg;
 401
 402         for_each_sg(sgl, sg, nents, i) {
 403                 sg->dma_address = dma_direct_map_page(dev, sg_page(sg),
 404                                 sg->offset, sg->length, dir, attrs);
 405                 if (sg->dma_address == DMA_MAPPING_ERROR)
 406                         goto out_unmap;
 407                 sg_dma_len(sg) = sg->length;
 408         }
 409
 410         return nents;
 411
 412 out_unmap:
 413         dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
 414         return 0;
 415 }
 416
 417 dma_addr_t dma_direct_map_resource(struct device *dev, phys_addr_t paddr,
 418                 size_t size, enum dma_data_direction dir, unsigned long attrs)
 419 {
 420         dma_addr_t dma_addr = paddr;
 421
 422         if (unlikely(!dma_capable(dev, dma_addr, size, false))) {
 423                 dev_err_once(dev,
 424                              "DMA addr %pad+%zu overflow (mask %llx, bus limit %llx).\n",
 425                              &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit);
 426                 WARN_ON_ONCE(1);
 427                 return DMA_MAPPING_ERROR;
 428         }
 429
 430         return dma_addr;
 431 }
 432
 433 int dma_direct_get_sgtable(struct device *dev, struct sg_table *sgt,
 434                 void *cpu_addr, dma_addr_t dma_addr, size_t size,
 435                 unsigned long attrs)
 436 {
 437         struct page *page = dma_direct_to_page(dev, dma_addr);
 438         int ret;
 439
 440         ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
 441         if (!ret)
 442                 sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
 443         return ret;
 444 }
 445
 446 bool dma_direct_can_mmap(struct device *dev)
 447 {
 448         return dev_is_dma_coherent(dev) ||
 449                 IS_ENABLED(CONFIG_DMA_NONCOHERENT_MMAP);
 450 }
 451
 452 int dma_direct_mmap(struct device *dev, struct vm_area_struct *vma,
 453                 void *cpu_addr, dma_addr_t dma_addr, size_t size,
 454                 unsigned long attrs)
 455 {
 456         unsigned long user_count = vma_pages(vma);
 457         unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 458         unsigned long pfn = PHYS_PFN(dma_to_phys(dev, dma_addr));
 459         int ret = -ENXIO;
 460
 461         vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
 462
 463         if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret))
 464                 return ret;
 465
 466         if (vma->vm_pgoff >= count || user_count > count - vma->vm_pgoff)
 467                 return -ENXIO;
 468         return remap_pfn_range(vma, vma->vm_start, pfn + vma->vm_pgoff,
 469                         user_count << PAGE_SHIFT, vma->vm_page_prot);
 470 }
 471
 472 int dma_direct_supported(struct device *dev, u64 mask)
 473 {
 474         u64 min_mask = (max_pfn - 1) << PAGE_SHIFT;
 475
 476         /*
 477          * Because 32-bit DMA masks are so common we expect every architecture
 478          * to be able to satisfy them - either by not supporting more physical
 479          * memory, or by providing a ZONE_DMA32.  If neither is the case, the
 480          * architecture needs to use an IOMMU instead of the direct mapping.
 481          */
 482         if (mask >= DMA_BIT_MASK(32))
 483                 return 1;
 484
 485         /*
 486          * This check needs to be against the actual bit mask value, so use
 487          * phys_to_dma_unencrypted() here so that the SME encryption mask isn't
 488          * part of the check.
 489          */
 490         if (IS_ENABLED(CONFIG_ZONE_DMA))
 491                 min_mask = min_t(u64, min_mask, DMA_BIT_MASK(zone_dma_bits));
 492         return mask >= phys_to_dma_unencrypted(dev, min_mask);
 493 }
 494
 495 size_t dma_direct_max_mapping_size(struct device *dev)
 496 {
 497         /* If SWIOTLB is active, use its maximum mapping size */
 498         if (is_swiotlb_active() &&
 499             (dma_addressing_limited(dev) || swiotlb_force == SWIOTLB_FORCE))
 500                 return swiotlb_max_mapping_size(dev);
 501         return SIZE_MAX;
 502 }
 503
 504 bool dma_direct_need_sync(struct device *dev, dma_addr_t dma_addr)
 505 {
 506         return !dev_is_dma_coherent(dev) ||
 507                 is_swiotlb_buffer(dma_to_phys(dev, dma_addr));
 508 }
 509
 510 /**
 511  * dma_direct_set_offset - Assign scalar offset for a single DMA range.
 512  * @dev:        device pointer; needed to "own" the alloced memory.
 513  * @cpu_start:  beginning of memory region covered by this offset.
 514  * @dma_start:  beginning of DMA/PCI region covered by this offset.
 515  * @size:       size of the region.
 516  *
 517  * This is for the simple case of a uniform offset which cannot
 518  * be discovered by "dma-ranges".
 519  *
 520  * It returns -ENOMEM if out of memory, -EINVAL if a map
 521  * already exists, 0 otherwise.
 522  *
 523  * Note: any call to this from a driver is a bug.  The mapping needs
 524  * to be described by the device tree or other firmware interfaces.
 525  */
 526 int dma_direct_set_offset(struct device *dev, phys_addr_t cpu_start,
 527                          dma_addr_t dma_start, u64 size)
 528 {
 529         struct bus_dma_region *map;
 530         u64 offset = (u64)cpu_start - (u64)dma_start;
 531
 532         if (dev->dma_range_map) {
 533                 dev_err(dev, "attempt to add DMA range to existing map\n");
 534                 return -EINVAL;
 535         }
 536
 537         if (!offset)
 538                 return 0;
 539
 540         map = kcalloc(2, sizeof(*map), GFP_KERNEL);
 541         if (!map)
 542                 return -ENOMEM;
 543         map[0].cpu_start = cpu_start;
 544         map[0].dma_start = dma_start;
 545         map[0].offset = offset;
 546         map[0].size = size;
 547         dev->dma_range_map = map;
 548         return 0;
 549 }