drivers/gpu/drm/drm_gem_shmem_helper.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2018 Noralf Trønnes
   4  */
   5
   6 #include <linux/dma-buf.h>
   7 #include <linux/export.h>
   8 #include <linux/module.h>
   9 #include <linux/mutex.h>
  10 #include <linux/shmem_fs.h>
  11 #include <linux/slab.h>
  12 #include <linux/vmalloc.h>
  13
  14 #ifdef CONFIG_X86
  15 #include <asm/set_memory.h>
  16 #endif
  17
  18 #include <drm/drm.h>
  19 #include <drm/drm_device.h>
  20 #include <drm/drm_drv.h>
  21 #include <drm/drm_gem_shmem_helper.h>
  22 #include <drm/drm_prime.h>
  23 #include <drm/drm_print.h>
  24
  25 MODULE_IMPORT_NS("DMA_BUF");
  26
  27 /**
  28  * DOC: overview
  29  *
  30  * This library provides helpers for GEM objects backed by shmem buffers
  31  * allocated using anonymous pageable memory.
  32  *
  33  * Functions that operate on the GEM object receive struct &drm_gem_shmem_object.
  34  * For GEM callback helpers in struct &drm_gem_object functions, see likewise
  35  * named functions with an _object_ infix (e.g., drm_gem_shmem_object_vmap() wraps
  36  * drm_gem_shmem_vmap()). These helpers perform the necessary type conversion.
  37  */
  38
  39 static const struct drm_gem_object_funcs drm_gem_shmem_funcs = {
  40         .free = drm_gem_shmem_object_free,
  41         .print_info = drm_gem_shmem_object_print_info,
  42         .pin = drm_gem_shmem_object_pin,
  43         .unpin = drm_gem_shmem_object_unpin,
  44         .get_sg_table = drm_gem_shmem_object_get_sg_table,
  45         .vmap = drm_gem_shmem_object_vmap,
  46         .vunmap = drm_gem_shmem_object_vunmap,
  47         .mmap = drm_gem_shmem_object_mmap,
  48         .vm_ops = &drm_gem_shmem_vm_ops,
  49 };
  50
  51 static struct drm_gem_shmem_object *
  52 __drm_gem_shmem_create(struct drm_device *dev, size_t size, bool private,
  53                        struct vfsmount *gemfs)
  54 {
  55         struct drm_gem_shmem_object *shmem;
  56         struct drm_gem_object *obj;
  57         int ret = 0;
  58
  59         size = PAGE_ALIGN(size);
  60
  61         if (dev->driver->gem_create_object) {
  62                 obj = dev->driver->gem_create_object(dev, size);
  63                 if (IS_ERR(obj))
  64                         return ERR_CAST(obj);
  65                 shmem = to_drm_gem_shmem_obj(obj);
  66         } else {
  67                 shmem = kzalloc(sizeof(*shmem), GFP_KERNEL);
  68                 if (!shmem)
  69                         return ERR_PTR(-ENOMEM);
  70                 obj = &shmem->base;
  71         }
  72
  73         if (!obj->funcs)
  74                 obj->funcs = &drm_gem_shmem_funcs;
  75
  76         if (private) {
  77                 drm_gem_private_object_init(dev, obj, size);
  78                 shmem->map_wc = false; /* dma-buf mappings use always writecombine */
  79         } else {
  80                 ret = drm_gem_object_init_with_mnt(dev, obj, size, gemfs);
  81         }
  82         if (ret) {
  83                 drm_gem_private_object_fini(obj);
  84                 goto err_free;
  85         }
  86
  87         ret = drm_gem_create_mmap_offset(obj);
  88         if (ret)
  89                 goto err_release;
  90
  91         INIT_LIST_HEAD(&shmem->madv_list);
  92
  93         if (!private) {
  94                 /*
  95                  * Our buffers are kept pinned, so allocating them
  96                  * from the MOVABLE zone is a really bad idea, and
  97                  * conflicts with CMA. See comments above new_inode()
  98                  * why this is required _and_ expected if you're
  99                  * going to pin these pages.
 100                  */
 101                 mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER |
 102                                      __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
 103         }
 104
 105         return shmem;
 106
 107 err_release:
 108         drm_gem_object_release(obj);
 109 err_free:
 110         kfree(obj);
 111
 112         return ERR_PTR(ret);
 113 }
 114 /**
 115  * drm_gem_shmem_create - Allocate an object with the given size
 116  * @dev: DRM device
 117  * @size: Size of the object to allocate
 118  *
 119  * This function creates a shmem GEM object.
 120  *
 121  * Returns:
 122  * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
 123  * error code on failure.
 124  */
 125 struct drm_gem_shmem_object *drm_gem_shmem_create(struct drm_device *dev, size_t size)
 126 {
 127         return __drm_gem_shmem_create(dev, size, false, NULL);
 128 }
 129 EXPORT_SYMBOL_GPL(drm_gem_shmem_create);
 130
 131 /**
 132  * drm_gem_shmem_create_with_mnt - Allocate an object with the given size in a
 133  * given mountpoint
 134  * @dev: DRM device
 135  * @size: Size of the object to allocate
 136  * @gemfs: tmpfs mount where the GEM object will be created
 137  *
 138  * This function creates a shmem GEM object in a given tmpfs mountpoint.
 139  *
 140  * Returns:
 141  * A struct drm_gem_shmem_object * on success or an ERR_PTR()-encoded negative
 142  * error code on failure.
 143  */
 144 struct drm_gem_shmem_object *drm_gem_shmem_create_with_mnt(struct drm_device *dev,
 145                                                            size_t size,
 146                                                            struct vfsmount *gemfs)
 147 {
 148         return __drm_gem_shmem_create(dev, size, false, gemfs);
 149 }
 150 EXPORT_SYMBOL_GPL(drm_gem_shmem_create_with_mnt);
 151
 152 /**
 153  * drm_gem_shmem_free - Free resources associated with a shmem GEM object
 154  * @shmem: shmem GEM object to free
 155  *
 156  * This function cleans up the GEM object state and frees the memory used to
 157  * store the object itself.
 158  */
 159 void drm_gem_shmem_free(struct drm_gem_shmem_object *shmem)
 160 {
 161         struct drm_gem_object *obj = &shmem->base;
 162
 163         if (obj->import_attach) {
 164                 drm_prime_gem_destroy(obj, shmem->sgt);
 165         } else {
 166                 dma_resv_lock(shmem->base.resv, NULL);
 167
 168                 drm_WARN_ON(obj->dev, shmem->vmap_use_count);
 169
 170                 if (shmem->sgt) {
 171                         dma_unmap_sgtable(obj->dev->dev, shmem->sgt,
 172                                           DMA_BIDIRECTIONAL, 0);
 173                         sg_free_table(shmem->sgt);
 174                         kfree(shmem->sgt);
 175                 }
 176                 if (shmem->pages)
 177                         drm_gem_shmem_put_pages(shmem);
 178
 179                 drm_WARN_ON(obj->dev, shmem->pages_use_count);
 180
 181                 dma_resv_unlock(shmem->base.resv);
 182         }
 183
 184         drm_gem_object_release(obj);
 185         kfree(shmem);
 186 }
 187 EXPORT_SYMBOL_GPL(drm_gem_shmem_free);
 188
 189 static int drm_gem_shmem_get_pages(struct drm_gem_shmem_object *shmem)
 190 {
 191         struct drm_gem_object *obj = &shmem->base;
 192         struct page **pages;
 193
 194         dma_resv_assert_held(shmem->base.resv);
 195
 196         if (shmem->pages_use_count++ > 0)
 197                 return 0;
 198
 199         pages = drm_gem_get_pages(obj);
 200         if (IS_ERR(pages)) {
 201                 drm_dbg_kms(obj->dev, "Failed to get pages (%ld)\n",
 202                             PTR_ERR(pages));
 203                 shmem->pages_use_count = 0;
 204                 return PTR_ERR(pages);
 205         }
 206
 207         /*
 208          * TODO: Allocating WC pages which are correctly flushed is only
 209          * supported on x86. Ideal solution would be a GFP_WC flag, which also
 210          * ttm_pool.c could use.
 211          */
 212 #ifdef CONFIG_X86
 213         if (shmem->map_wc)
 214                 set_pages_array_wc(pages, obj->size >> PAGE_SHIFT);
 215 #endif
 216
 217         shmem->pages = pages;
 218
 219         return 0;
 220 }
 221
 222 /*
 223  * drm_gem_shmem_put_pages - Decrease use count on the backing pages for a shmem GEM object
 224  * @shmem: shmem GEM object
 225  *
 226  * This function decreases the use count and puts the backing pages when use drops to zero.
 227  */
 228 void drm_gem_shmem_put_pages(struct drm_gem_shmem_object *shmem)
 229 {
 230         struct drm_gem_object *obj = &shmem->base;
 231
 232         dma_resv_assert_held(shmem->base.resv);
 233
 234         if (drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
 235                 return;
 236
 237         if (--shmem->pages_use_count > 0)
 238                 return;
 239
 240 #ifdef CONFIG_X86
 241         if (shmem->map_wc)
 242                 set_pages_array_wb(shmem->pages, obj->size >> PAGE_SHIFT);
 243 #endif
 244
 245         drm_gem_put_pages(obj, shmem->pages,
 246                           shmem->pages_mark_dirty_on_put,
 247                           shmem->pages_mark_accessed_on_put);
 248         shmem->pages = NULL;
 249 }
 250 EXPORT_SYMBOL(drm_gem_shmem_put_pages);
 251
 252 int drm_gem_shmem_pin_locked(struct drm_gem_shmem_object *shmem)
 253 {
 254         int ret;
 255
 256         dma_resv_assert_held(shmem->base.resv);
 257
 258         drm_WARN_ON(shmem->base.dev, shmem->base.import_attach);
 259
 260         ret = drm_gem_shmem_get_pages(shmem);
 261
 262         return ret;
 263 }
 264 EXPORT_SYMBOL(drm_gem_shmem_pin_locked);
 265
 266 void drm_gem_shmem_unpin_locked(struct drm_gem_shmem_object *shmem)
 267 {
 268         dma_resv_assert_held(shmem->base.resv);
 269
 270         drm_gem_shmem_put_pages(shmem);
 271 }
 272 EXPORT_SYMBOL(drm_gem_shmem_unpin_locked);
 273
 274 /**
 275  * drm_gem_shmem_pin - Pin backing pages for a shmem GEM object
 276  * @shmem: shmem GEM object
 277  *
 278  * This function makes sure the backing pages are pinned in memory while the
 279  * buffer is exported.
 280  *
 281  * Returns:
 282  * 0 on success or a negative error code on failure.
 283  */
 284 int drm_gem_shmem_pin(struct drm_gem_shmem_object *shmem)
 285 {
 286         struct drm_gem_object *obj = &shmem->base;
 287         int ret;
 288
 289         drm_WARN_ON(obj->dev, obj->import_attach);
 290
 291         ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
 292         if (ret)
 293                 return ret;
 294         ret = drm_gem_shmem_pin_locked(shmem);
 295         dma_resv_unlock(shmem->base.resv);
 296
 297         return ret;
 298 }
 299 EXPORT_SYMBOL(drm_gem_shmem_pin);
 300
 301 /**
 302  * drm_gem_shmem_unpin - Unpin backing pages for a shmem GEM object
 303  * @shmem: shmem GEM object
 304  *
 305  * This function removes the requirement that the backing pages are pinned in
 306  * memory.
 307  */
 308 void drm_gem_shmem_unpin(struct drm_gem_shmem_object *shmem)
 309 {
 310         struct drm_gem_object *obj = &shmem->base;
 311
 312         drm_WARN_ON(obj->dev, obj->import_attach);
 313
 314         dma_resv_lock(shmem->base.resv, NULL);
 315         drm_gem_shmem_unpin_locked(shmem);
 316         dma_resv_unlock(shmem->base.resv);
 317 }
 318 EXPORT_SYMBOL(drm_gem_shmem_unpin);
 319
 320 /*
 321  * drm_gem_shmem_vmap - Create a virtual mapping for a shmem GEM object
 322  * @shmem: shmem GEM object
 323  * @map: Returns the kernel virtual address of the SHMEM GEM object's backing
 324  *       store.
 325  *
 326  * This function makes sure that a contiguous kernel virtual address mapping
 327  * exists for the buffer backing the shmem GEM object. It hides the differences
 328  * between dma-buf imported and natively allocated objects.
 329  *
 330  * Acquired mappings should be cleaned up by calling drm_gem_shmem_vunmap().
 331  *
 332  * Returns:
 333  * 0 on success or a negative error code on failure.
 334  */
 335 int drm_gem_shmem_vmap(struct drm_gem_shmem_object *shmem,
 336                        struct iosys_map *map)
 337 {
 338         struct drm_gem_object *obj = &shmem->base;
 339         int ret = 0;
 340
 341         if (obj->import_attach) {
 342                 ret = dma_buf_vmap(obj->import_attach->dmabuf, map);
 343                 if (!ret) {
 344                         if (drm_WARN_ON(obj->dev, map->is_iomem)) {
 345                                 dma_buf_vunmap(obj->import_attach->dmabuf, map);
 346                                 return -EIO;
 347                         }
 348                 }
 349         } else {
 350                 pgprot_t prot = PAGE_KERNEL;
 351
 352                 dma_resv_assert_held(shmem->base.resv);
 353
 354                 if (shmem->vmap_use_count++ > 0) {
 355                         iosys_map_set_vaddr(map, shmem->vaddr);
 356                         return 0;
 357                 }
 358
 359                 ret = drm_gem_shmem_get_pages(shmem);
 360                 if (ret)
 361                         goto err_zero_use;
 362
 363                 if (shmem->map_wc)
 364                         prot = pgprot_writecombine(prot);
 365                 shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,
 366                                     VM_MAP, prot);
 367                 if (!shmem->vaddr)
 368                         ret = -ENOMEM;
 369                 else
 370                         iosys_map_set_vaddr(map, shmem->vaddr);
 371         }
 372
 373         if (ret) {
 374                 drm_dbg_kms(obj->dev, "Failed to vmap pages, error %d\n", ret);
 375                 goto err_put_pages;
 376         }
 377
 378         return 0;
 379
 380 err_put_pages:
 381         if (!obj->import_attach)
 382                 drm_gem_shmem_put_pages(shmem);
 383 err_zero_use:
 384         shmem->vmap_use_count = 0;
 385
 386         return ret;
 387 }
 388 EXPORT_SYMBOL(drm_gem_shmem_vmap);
 389
 390 /*
 391  * drm_gem_shmem_vunmap - Unmap a virtual mapping for a shmem GEM object
 392  * @shmem: shmem GEM object
 393  * @map: Kernel virtual address where the SHMEM GEM object was mapped
 394  *
 395  * This function cleans up a kernel virtual address mapping acquired by
 396  * drm_gem_shmem_vmap(). The mapping is only removed when the use count drops to
 397  * zero.
 398  *
 399  * This function hides the differences between dma-buf imported and natively
 400  * allocated objects.
 401  */
 402 void drm_gem_shmem_vunmap(struct drm_gem_shmem_object *shmem,
 403                           struct iosys_map *map)
 404 {
 405         struct drm_gem_object *obj = &shmem->base;
 406
 407         if (obj->import_attach) {
 408                 dma_buf_vunmap(obj->import_attach->dmabuf, map);
 409         } else {
 410                 dma_resv_assert_held(shmem->base.resv);
 411
 412                 if (drm_WARN_ON_ONCE(obj->dev, !shmem->vmap_use_count))
 413                         return;
 414
 415                 if (--shmem->vmap_use_count > 0)
 416                         return;
 417
 418                 vunmap(shmem->vaddr);
 419                 drm_gem_shmem_put_pages(shmem);
 420         }
 421
 422         shmem->vaddr = NULL;
 423 }
 424 EXPORT_SYMBOL(drm_gem_shmem_vunmap);
 425
 426 static int
 427 drm_gem_shmem_create_with_handle(struct drm_file *file_priv,
 428                                  struct drm_device *dev, size_t size,
 429                                  uint32_t *handle)
 430 {
 431         struct drm_gem_shmem_object *shmem;
 432         int ret;
 433
 434         shmem = drm_gem_shmem_create(dev, size);
 435         if (IS_ERR(shmem))
 436                 return PTR_ERR(shmem);
 437
 438         /*
 439          * Allocate an id of idr table where the obj is registered
 440          * and handle has the id what user can see.
 441          */
 442         ret = drm_gem_handle_create(file_priv, &shmem->base, handle);
 443         /* drop reference from allocate - handle holds it now. */
 444         drm_gem_object_put(&shmem->base);
 445
 446         return ret;
 447 }
 448
 449 /* Update madvise status, returns true if not purged, else
 450  * false or -errno.
 451  */
 452 int drm_gem_shmem_madvise(struct drm_gem_shmem_object *shmem, int madv)
 453 {
 454         dma_resv_assert_held(shmem->base.resv);
 455
 456         if (shmem->madv >= 0)
 457                 shmem->madv = madv;
 458
 459         madv = shmem->madv;
 460
 461         return (madv >= 0);
 462 }
 463 EXPORT_SYMBOL(drm_gem_shmem_madvise);
 464
 465 void drm_gem_shmem_purge(struct drm_gem_shmem_object *shmem)
 466 {
 467         struct drm_gem_object *obj = &shmem->base;
 468         struct drm_device *dev = obj->dev;
 469
 470         dma_resv_assert_held(shmem->base.resv);
 471
 472         drm_WARN_ON(obj->dev, !drm_gem_shmem_is_purgeable(shmem));
 473
 474         dma_unmap_sgtable(dev->dev, shmem->sgt, DMA_BIDIRECTIONAL, 0);
 475         sg_free_table(shmem->sgt);
 476         kfree(shmem->sgt);
 477         shmem->sgt = NULL;
 478
 479         drm_gem_shmem_put_pages(shmem);
 480
 481         shmem->madv = -1;
 482
 483         drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);
 484         drm_gem_free_mmap_offset(obj);
 485
 486         /* Our goal here is to return as much of the memory as
 487          * is possible back to the system as we are called from OOM.
 488          * To do this we must instruct the shmfs to drop all of its
 489          * backing pages, *now*.
 490          */
 491         shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1);
 492
 493         invalidate_mapping_pages(file_inode(obj->filp)->i_mapping, 0, (loff_t)-1);
 494 }
 495 EXPORT_SYMBOL(drm_gem_shmem_purge);
 496
 497 /**
 498  * drm_gem_shmem_dumb_create - Create a dumb shmem buffer object
 499  * @file: DRM file structure to create the dumb buffer for
 500  * @dev: DRM device
 501  * @args: IOCTL data
 502  *
 503  * This function computes the pitch of the dumb buffer and rounds it up to an
 504  * integer number of bytes per pixel. Drivers for hardware that doesn't have
 505  * any additional restrictions on the pitch can directly use this function as
 506  * their &drm_driver.dumb_create callback.
 507  *
 508  * For hardware with additional restrictions, drivers can adjust the fields
 509  * set up by userspace before calling into this function.
 510  *
 511  * Returns:
 512  * 0 on success or a negative error code on failure.
 513  */
 514 int drm_gem_shmem_dumb_create(struct drm_file *file, struct drm_device *dev,
 515                               struct drm_mode_create_dumb *args)
 516 {
 517         u32 min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 518
 519         if (!args->pitch || !args->size) {
 520                 args->pitch = min_pitch;
 521                 args->size = PAGE_ALIGN(args->pitch * args->height);
 522         } else {
 523                 /* ensure sane minimum values */
 524                 if (args->pitch < min_pitch)
 525                         args->pitch = min_pitch;
 526                 if (args->size < args->pitch * args->height)
 527                         args->size = PAGE_ALIGN(args->pitch * args->height);
 528         }
 529
 530         return drm_gem_shmem_create_with_handle(file, dev, args->size, &args->handle);
 531 }
 532 EXPORT_SYMBOL_GPL(drm_gem_shmem_dumb_create);
 533
 534 static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf)
 535 {
 536         struct vm_area_struct *vma = vmf->vma;
 537         struct drm_gem_object *obj = vma->vm_private_data;
 538         struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
 539         loff_t num_pages = obj->size >> PAGE_SHIFT;
 540         vm_fault_t ret;
 541         struct page *page;
 542         pgoff_t page_offset;
 543
 544         /* We don't use vmf->pgoff since that has the fake offset */
 545         page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
 546
 547         dma_resv_lock(shmem->base.resv, NULL);
 548
 549         if (page_offset >= num_pages ||
 550             drm_WARN_ON_ONCE(obj->dev, !shmem->pages) ||
 551             shmem->madv < 0) {
 552                 ret = VM_FAULT_SIGBUS;
 553         } else {
 554                 page = shmem->pages[page_offset];
 555
 556                 ret = vmf_insert_pfn(vma, vmf->address, page_to_pfn(page));
 557         }
 558
 559         dma_resv_unlock(shmem->base.resv);
 560
 561         return ret;
 562 }
 563
 564 static void drm_gem_shmem_vm_open(struct vm_area_struct *vma)
 565 {
 566         struct drm_gem_object *obj = vma->vm_private_data;
 567         struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
 568
 569         drm_WARN_ON(obj->dev, obj->import_attach);
 570
 571         dma_resv_lock(shmem->base.resv, NULL);
 572
 573         /*
 574          * We should have already pinned the pages when the buffer was first
 575          * mmap'd, vm_open() just grabs an additional reference for the new
 576          * mm the vma is getting copied into (ie. on fork()).
 577          */
 578         if (!drm_WARN_ON_ONCE(obj->dev, !shmem->pages_use_count))
 579                 shmem->pages_use_count++;
 580
 581         dma_resv_unlock(shmem->base.resv);
 582
 583         drm_gem_vm_open(vma);
 584 }
 585
 586 static void drm_gem_shmem_vm_close(struct vm_area_struct *vma)
 587 {
 588         struct drm_gem_object *obj = vma->vm_private_data;
 589         struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
 590
 591         dma_resv_lock(shmem->base.resv, NULL);
 592         drm_gem_shmem_put_pages(shmem);
 593         dma_resv_unlock(shmem->base.resv);
 594
 595         drm_gem_vm_close(vma);
 596 }
 597
 598 const struct vm_operations_struct drm_gem_shmem_vm_ops = {
 599         .fault = drm_gem_shmem_fault,
 600         .open = drm_gem_shmem_vm_open,
 601         .close = drm_gem_shmem_vm_close,
 602 };
 603 EXPORT_SYMBOL_GPL(drm_gem_shmem_vm_ops);
 604
 605 /**
 606  * drm_gem_shmem_mmap - Memory-map a shmem GEM object
 607  * @shmem: shmem GEM object
 608  * @vma: VMA for the area to be mapped
 609  *
 610  * This function implements an augmented version of the GEM DRM file mmap
 611  * operation for shmem objects.
 612  *
 613  * Returns:
 614  * 0 on success or a negative error code on failure.
 615  */
 616 int drm_gem_shmem_mmap(struct drm_gem_shmem_object *shmem, struct vm_area_struct *vma)
 617 {
 618         struct drm_gem_object *obj = &shmem->base;
 619         int ret;
 620
 621         if (obj->import_attach) {
 622                 /* Reset both vm_ops and vm_private_data, so we don't end up with
 623                  * vm_ops pointing to our implementation if the dma-buf backend
 624                  * doesn't set those fields.
 625                  */
 626                 vma->vm_private_data = NULL;
 627                 vma->vm_ops = NULL;
 628
 629                 ret = dma_buf_mmap(obj->dma_buf, vma, 0);
 630
 631                 /* Drop the reference drm_gem_mmap_obj() acquired.*/
 632                 if (!ret)
 633                         drm_gem_object_put(obj);
 634
 635                 return ret;
 636         }
 637
 638         if (is_cow_mapping(vma->vm_flags))
 639                 return -EINVAL;
 640
 641         dma_resv_lock(shmem->base.resv, NULL);
 642         ret = drm_gem_shmem_get_pages(shmem);
 643         dma_resv_unlock(shmem->base.resv);
 644
 645         if (ret)
 646                 return ret;
 647
 648         vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
 649         vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 650         if (shmem->map_wc)
 651                 vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
 652
 653         return 0;
 654 }
 655 EXPORT_SYMBOL_GPL(drm_gem_shmem_mmap);
 656
 657 /**
 658  * drm_gem_shmem_print_info() - Print &drm_gem_shmem_object info for debugfs
 659  * @shmem: shmem GEM object
 660  * @p: DRM printer
 661  * @indent: Tab indentation level
 662  */
 663 void drm_gem_shmem_print_info(const struct drm_gem_shmem_object *shmem,
 664                               struct drm_printer *p, unsigned int indent)
 665 {
 666         if (shmem->base.import_attach)
 667                 return;
 668
 669         drm_printf_indent(p, indent, "pages_use_count=%u\n", shmem->pages_use_count);
 670         drm_printf_indent(p, indent, "vmap_use_count=%u\n", shmem->vmap_use_count);
 671         drm_printf_indent(p, indent, "vaddr=%p\n", shmem->vaddr);
 672 }
 673 EXPORT_SYMBOL(drm_gem_shmem_print_info);
 674
 675 /**
 676  * drm_gem_shmem_get_sg_table - Provide a scatter/gather table of pinned
 677  *                              pages for a shmem GEM object
 678  * @shmem: shmem GEM object
 679  *
 680  * This function exports a scatter/gather table suitable for PRIME usage by
 681  * calling the standard DMA mapping API.
 682  *
 683  * Drivers who need to acquire an scatter/gather table for objects need to call
 684  * drm_gem_shmem_get_pages_sgt() instead.
 685  *
 686  * Returns:
 687  * A pointer to the scatter/gather table of pinned pages or error pointer on failure.
 688  */
 689 struct sg_table *drm_gem_shmem_get_sg_table(struct drm_gem_shmem_object *shmem)
 690 {
 691         struct drm_gem_object *obj = &shmem->base;
 692
 693         drm_WARN_ON(obj->dev, obj->import_attach);
 694
 695         return drm_prime_pages_to_sg(obj->dev, shmem->pages, obj->size >> PAGE_SHIFT);
 696 }
 697 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_sg_table);
 698
 699 static struct sg_table *drm_gem_shmem_get_pages_sgt_locked(struct drm_gem_shmem_object *shmem)
 700 {
 701         struct drm_gem_object *obj = &shmem->base;
 702         int ret;
 703         struct sg_table *sgt;
 704
 705         if (shmem->sgt)
 706                 return shmem->sgt;
 707
 708         drm_WARN_ON(obj->dev, obj->import_attach);
 709
 710         ret = drm_gem_shmem_get_pages(shmem);
 711         if (ret)
 712                 return ERR_PTR(ret);
 713
 714         sgt = drm_gem_shmem_get_sg_table(shmem);
 715         if (IS_ERR(sgt)) {
 716                 ret = PTR_ERR(sgt);
 717                 goto err_put_pages;
 718         }
 719         /* Map the pages for use by the h/w. */
 720         ret = dma_map_sgtable(obj->dev->dev, sgt, DMA_BIDIRECTIONAL, 0);
 721         if (ret)
 722                 goto err_free_sgt;
 723
 724         shmem->sgt = sgt;
 725
 726         return sgt;
 727
 728 err_free_sgt:
 729         sg_free_table(sgt);
 730         kfree(sgt);
 731 err_put_pages:
 732         drm_gem_shmem_put_pages(shmem);
 733         return ERR_PTR(ret);
 734 }
 735
 736 /**
 737  * drm_gem_shmem_get_pages_sgt - Pin pages, dma map them, and return a
 738  *                               scatter/gather table for a shmem GEM object.
 739  * @shmem: shmem GEM object
 740  *
 741  * This function returns a scatter/gather table suitable for driver usage. If
 742  * the sg table doesn't exist, the pages are pinned, dma-mapped, and a sg
 743  * table created.
 744  *
 745  * This is the main function for drivers to get at backing storage, and it hides
 746  * and difference between dma-buf imported and natively allocated objects.
 747  * drm_gem_shmem_get_sg_table() should not be directly called by drivers.
 748  *
 749  * Returns:
 750  * A pointer to the scatter/gather table of pinned pages or errno on failure.
 751  */
 752 struct sg_table *drm_gem_shmem_get_pages_sgt(struct drm_gem_shmem_object *shmem)
 753 {
 754         int ret;
 755         struct sg_table *sgt;
 756
 757         ret = dma_resv_lock_interruptible(shmem->base.resv, NULL);
 758         if (ret)
 759                 return ERR_PTR(ret);
 760         sgt = drm_gem_shmem_get_pages_sgt_locked(shmem);
 761         dma_resv_unlock(shmem->base.resv);
 762
 763         return sgt;
 764 }
 765 EXPORT_SYMBOL_GPL(drm_gem_shmem_get_pages_sgt);
 766
 767 /**
 768  * drm_gem_shmem_prime_import_sg_table - Produce a shmem GEM object from
 769  *                 another driver's scatter/gather table of pinned pages
 770  * @dev: Device to import into
 771  * @attach: DMA-BUF attachment
 772  * @sgt: Scatter/gather table of pinned pages
 773  *
 774  * This function imports a scatter/gather table exported via DMA-BUF by
 775  * another driver. Drivers that use the shmem helpers should set this as their
 776  * &drm_driver.gem_prime_import_sg_table callback.
 777  *
 778  * Returns:
 779  * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
 780  * error code on failure.
 781  */
 782 struct drm_gem_object *
 783 drm_gem_shmem_prime_import_sg_table(struct drm_device *dev,
 784                                     struct dma_buf_attachment *attach,
 785                                     struct sg_table *sgt)
 786 {
 787         size_t size = PAGE_ALIGN(attach->dmabuf->size);
 788         struct drm_gem_shmem_object *shmem;
 789
 790         shmem = __drm_gem_shmem_create(dev, size, true, NULL);
 791         if (IS_ERR(shmem))
 792                 return ERR_CAST(shmem);
 793
 794         shmem->sgt = sgt;
 795
 796         drm_dbg_prime(dev, "size = %zu\n", size);
 797
 798         return &shmem->base;
 799 }
 800 EXPORT_SYMBOL_GPL(drm_gem_shmem_prime_import_sg_table);
 801
 802 MODULE_DESCRIPTION("DRM SHMEM memory-management helpers");
 803 MODULE_IMPORT_NS("DMA_BUF");
 804 MODULE_LICENSE("GPL v2");