drivers/gpu/drm/i915/gem/i915_gem_pages.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright © 2014-2016 Intel Corporation
   5  */
   6
   7 #include "i915_drv.h"
   8 #include "i915_gem_object.h"
   9 #include "i915_scatterlist.h"
  10
  11 void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
  12                                  struct sg_table *pages,
  13                                  unsigned int sg_page_sizes)
  14 {
  15         struct drm_i915_private *i915 = to_i915(obj->base.dev);
  16         unsigned long supported = INTEL_INFO(i915)->page_sizes;
  17         int i;
  18
  19         lockdep_assert_held(&obj->mm.lock);
  20
  21         /* Make the pages coherent with the GPU (flushing any swapin). */
  22         if (obj->cache_dirty) {
  23                 obj->write_domain = 0;
  24                 if (i915_gem_object_has_struct_page(obj))
  25                         drm_clflush_sg(pages);
  26                 obj->cache_dirty = false;
  27         }
  28
  29         obj->mm.get_page.sg_pos = pages->sgl;
  30         obj->mm.get_page.sg_idx = 0;
  31
  32         obj->mm.pages = pages;
  33
  34         if (i915_gem_object_is_tiled(obj) &&
  35             i915->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
  36                 GEM_BUG_ON(obj->mm.quirked);
  37                 __i915_gem_object_pin_pages(obj);
  38                 obj->mm.quirked = true;
  39         }
  40
  41         GEM_BUG_ON(!sg_page_sizes);
  42         obj->mm.page_sizes.phys = sg_page_sizes;
  43
  44         /*
  45          * Calculate the supported page-sizes which fit into the given
  46          * sg_page_sizes. This will give us the page-sizes which we may be able
  47          * to use opportunistically when later inserting into the GTT. For
  48          * example if phys=2G, then in theory we should be able to use 1G, 2M,
  49          * 64K or 4K pages, although in practice this will depend on a number of
  50          * other factors.
  51          */
  52         obj->mm.page_sizes.sg = 0;
  53         for_each_set_bit(i, &supported, ilog2(I915_GTT_MAX_PAGE_SIZE) + 1) {
  54                 if (obj->mm.page_sizes.phys & ~0u << i)
  55                         obj->mm.page_sizes.sg |= BIT(i);
  56         }
  57         GEM_BUG_ON(!HAS_PAGE_SIZES(i915, obj->mm.page_sizes.sg));
  58
  59         if (i915_gem_object_is_shrinkable(obj)) {
  60                 struct list_head *list;
  61                 unsigned long flags;
  62
  63                 spin_lock_irqsave(&i915->mm.obj_lock, flags);
  64
  65                 i915->mm.shrink_count++;
  66                 i915->mm.shrink_memory += obj->base.size;
  67
  68                 if (obj->mm.madv != I915_MADV_WILLNEED)
  69                         list = &i915->mm.purge_list;
  70                 else
  71                         list = &i915->mm.shrink_list;
  72                 list_add_tail(&obj->mm.link, list);
  73
  74                 spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
  75         }
  76 }
  77
  78 int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
  79 {
  80         int err;
  81
  82         if (unlikely(obj->mm.madv != I915_MADV_WILLNEED)) {
  83                 DRM_DEBUG("Attempting to obtain a purgeable object\n");
  84                 return -EFAULT;
  85         }
  86
  87         err = obj->ops->get_pages(obj);
  88         GEM_BUG_ON(!err && !i915_gem_object_has_pages(obj));
  89
  90         return err;
  91 }
  92
  93 /* Ensure that the associated pages are gathered from the backing storage
  94  * and pinned into our object. i915_gem_object_pin_pages() may be called
  95  * multiple times before they are released by a single call to
  96  * i915_gem_object_unpin_pages() - once the pages are no longer referenced
  97  * either as a result of memory pressure (reaping pages under the shrinker)
  98  * or as the object is itself released.
  99  */
 100 int __i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
 101 {
 102         int err;
 103
 104         err = mutex_lock_interruptible(&obj->mm.lock);
 105         if (err)
 106                 return err;
 107
 108         if (unlikely(!i915_gem_object_has_pages(obj))) {
 109                 GEM_BUG_ON(i915_gem_object_has_pinned_pages(obj));
 110
 111                 err = ____i915_gem_object_get_pages(obj);
 112                 if (err)
 113                         goto unlock;
 114
 115                 smp_mb__before_atomic();
 116         }
 117         atomic_inc(&obj->mm.pages_pin_count);
 118
 119 unlock:
 120         mutex_unlock(&obj->mm.lock);
 121         return err;
 122 }
 123
 124 /* Immediately discard the backing storage */
 125 void i915_gem_object_truncate(struct drm_i915_gem_object *obj)
 126 {
 127         drm_gem_free_mmap_offset(&obj->base);
 128         if (obj->ops->truncate)
 129                 obj->ops->truncate(obj);
 130 }
 131
 132 /* Try to discard unwanted pages */
 133 void i915_gem_object_writeback(struct drm_i915_gem_object *obj)
 134 {
 135         lockdep_assert_held(&obj->mm.lock);
 136         GEM_BUG_ON(i915_gem_object_has_pages(obj));
 137
 138         if (obj->ops->writeback)
 139                 obj->ops->writeback(obj);
 140 }
 141
 142 static void __i915_gem_object_reset_page_iter(struct drm_i915_gem_object *obj)
 143 {
 144         struct radix_tree_iter iter;
 145         void __rcu **slot;
 146
 147         rcu_read_lock();
 148         radix_tree_for_each_slot(slot, &obj->mm.get_page.radix, &iter, 0)
 149                 radix_tree_delete(&obj->mm.get_page.radix, iter.index);
 150         rcu_read_unlock();
 151 }
 152
 153 struct sg_table *
 154 __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
 155 {
 156         struct drm_i915_private *i915 = to_i915(obj->base.dev);
 157         struct sg_table *pages;
 158
 159         pages = fetch_and_zero(&obj->mm.pages);
 160         if (IS_ERR_OR_NULL(pages))
 161                 return pages;
 162
 163         if (i915_gem_object_is_shrinkable(obj)) {
 164                 unsigned long flags;
 165
 166                 spin_lock_irqsave(&i915->mm.obj_lock, flags);
 167
 168                 list_del(&obj->mm.link);
 169                 i915->mm.shrink_count--;
 170                 i915->mm.shrink_memory -= obj->base.size;
 171
 172                 spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 173         }
 174
 175         if (obj->mm.mapping) {
 176                 void *ptr;
 177
 178                 ptr = page_mask_bits(obj->mm.mapping);
 179                 if (is_vmalloc_addr(ptr))
 180                         vunmap(ptr);
 181                 else
 182                         kunmap(kmap_to_page(ptr));
 183
 184                 obj->mm.mapping = NULL;
 185         }
 186
 187         __i915_gem_object_reset_page_iter(obj);
 188         obj->mm.page_sizes.phys = obj->mm.page_sizes.sg = 0;
 189
 190         return pages;
 191 }
 192
 193 int __i915_gem_object_put_pages(struct drm_i915_gem_object *obj,
 194                                 enum i915_mm_subclass subclass)
 195 {
 196         struct sg_table *pages;
 197         int err;
 198
 199         if (i915_gem_object_has_pinned_pages(obj))
 200                 return -EBUSY;
 201
 202         GEM_BUG_ON(atomic_read(&obj->bind_count));
 203
 204         /* May be called by shrinker from within get_pages() (on another bo) */
 205         mutex_lock_nested(&obj->mm.lock, subclass);
 206         if (unlikely(atomic_read(&obj->mm.pages_pin_count))) {
 207                 err = -EBUSY;
 208                 goto unlock;
 209         }
 210
 211         /*
 212          * ->put_pages might need to allocate memory for the bit17 swizzle
 213          * array, hence protect them from being reaped by removing them from gtt
 214          * lists early.
 215          */
 216         pages = __i915_gem_object_unset_pages(obj);
 217
 218         /*
 219          * XXX Temporary hijinx to avoid updating all backends to handle
 220          * NULL pages. In the future, when we have more asynchronous
 221          * get_pages backends we should be better able to handle the
 222          * cancellation of the async task in a more uniform manner.
 223          */
 224         if (!pages && !i915_gem_object_needs_async_cancel(obj))
 225                 pages = ERR_PTR(-EINVAL);
 226
 227         if (!IS_ERR(pages))
 228                 obj->ops->put_pages(obj, pages);
 229
 230         err = 0;
 231 unlock:
 232         mutex_unlock(&obj->mm.lock);
 233
 234         return err;
 235 }
 236
 237 /* The 'mapping' part of i915_gem_object_pin_map() below */
 238 static void *i915_gem_object_map(const struct drm_i915_gem_object *obj,
 239                                  enum i915_map_type type)
 240 {
 241         unsigned long n_pages = obj->base.size >> PAGE_SHIFT;
 242         struct sg_table *sgt = obj->mm.pages;
 243         struct sgt_iter sgt_iter;
 244         struct page *page;
 245         struct page *stack_pages[32];
 246         struct page **pages = stack_pages;
 247         unsigned long i = 0;
 248         pgprot_t pgprot;
 249         void *addr;
 250
 251         /* A single page can always be kmapped */
 252         if (n_pages == 1 && type == I915_MAP_WB)
 253                 return kmap(sg_page(sgt->sgl));
 254
 255         if (n_pages > ARRAY_SIZE(stack_pages)) {
 256                 /* Too big for stack -- allocate temporary array instead */
 257                 pages = kvmalloc_array(n_pages, sizeof(*pages), GFP_KERNEL);
 258                 if (!pages)
 259                         return NULL;
 260         }
 261
 262         for_each_sgt_page(page, sgt_iter, sgt)
 263                 pages[i++] = page;
 264
 265         /* Check that we have the expected number of pages */
 266         GEM_BUG_ON(i != n_pages);
 267
 268         switch (type) {
 269         default:
 270                 MISSING_CASE(type);
 271                 /* fallthrough - to use PAGE_KERNEL anyway */
 272         case I915_MAP_WB:
 273                 pgprot = PAGE_KERNEL;
 274                 break;
 275         case I915_MAP_WC:
 276                 pgprot = pgprot_writecombine(PAGE_KERNEL_IO);
 277                 break;
 278         }
 279         addr = vmap(pages, n_pages, 0, pgprot);
 280
 281         if (pages != stack_pages)
 282                 kvfree(pages);
 283
 284         return addr;
 285 }
 286
 287 /* get, pin, and map the pages of the object into kernel space */
 288 void *i915_gem_object_pin_map(struct drm_i915_gem_object *obj,
 289                               enum i915_map_type type)
 290 {
 291         enum i915_map_type has_type;
 292         bool pinned;
 293         void *ptr;
 294         int err;
 295
 296         if (unlikely(!i915_gem_object_has_struct_page(obj)))
 297                 return ERR_PTR(-ENXIO);
 298
 299         err = mutex_lock_interruptible(&obj->mm.lock);
 300         if (err)
 301                 return ERR_PTR(err);
 302
 303         pinned = !(type & I915_MAP_OVERRIDE);
 304         type &= ~I915_MAP_OVERRIDE;
 305
 306         if (!atomic_inc_not_zero(&obj->mm.pages_pin_count)) {
 307                 if (unlikely(!i915_gem_object_has_pages(obj))) {
 308                         GEM_BUG_ON(i915_gem_object_has_pinned_pages(obj));
 309
 310                         err = ____i915_gem_object_get_pages(obj);
 311                         if (err)
 312                                 goto err_unlock;
 313
 314                         smp_mb__before_atomic();
 315                 }
 316                 atomic_inc(&obj->mm.pages_pin_count);
 317                 pinned = false;
 318         }
 319         GEM_BUG_ON(!i915_gem_object_has_pages(obj));
 320
 321         ptr = page_unpack_bits(obj->mm.mapping, &has_type);
 322         if (ptr && has_type != type) {
 323                 if (pinned) {
 324                         err = -EBUSY;
 325                         goto err_unpin;
 326                 }
 327
 328                 if (is_vmalloc_addr(ptr))
 329                         vunmap(ptr);
 330                 else
 331                         kunmap(kmap_to_page(ptr));
 332
 333                 ptr = obj->mm.mapping = NULL;
 334         }
 335
 336         if (!ptr) {
 337                 ptr = i915_gem_object_map(obj, type);
 338                 if (!ptr) {
 339                         err = -ENOMEM;
 340                         goto err_unpin;
 341                 }
 342
 343                 obj->mm.mapping = page_pack_bits(ptr, type);
 344         }
 345
 346 out_unlock:
 347         mutex_unlock(&obj->mm.lock);
 348         return ptr;
 349
 350 err_unpin:
 351         atomic_dec(&obj->mm.pages_pin_count);
 352 err_unlock:
 353         ptr = ERR_PTR(err);
 354         goto out_unlock;
 355 }
 356
 357 void __i915_gem_object_flush_map(struct drm_i915_gem_object *obj,
 358                                  unsigned long offset,
 359                                  unsigned long size)
 360 {
 361         enum i915_map_type has_type;
 362         void *ptr;
 363
 364         GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
 365         GEM_BUG_ON(range_overflows_t(typeof(obj->base.size),
 366                                      offset, size, obj->base.size));
 367
 368         obj->mm.dirty = true;
 369
 370         if (obj->cache_coherent & I915_BO_CACHE_COHERENT_FOR_WRITE)
 371                 return;
 372
 373         ptr = page_unpack_bits(obj->mm.mapping, &has_type);
 374         if (has_type == I915_MAP_WC)
 375                 return;
 376
 377         drm_clflush_virt_range(ptr + offset, size);
 378         if (size == obj->base.size) {
 379                 obj->write_domain &= ~I915_GEM_DOMAIN_CPU;
 380                 obj->cache_dirty = false;
 381         }
 382 }
 383
 384 struct scatterlist *
 385 i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
 386                        unsigned int n,
 387                        unsigned int *offset)
 388 {
 389         struct i915_gem_object_page_iter *iter = &obj->mm.get_page;
 390         struct scatterlist *sg;
 391         unsigned int idx, count;
 392
 393         might_sleep();
 394         GEM_BUG_ON(n >= obj->base.size >> PAGE_SHIFT);
 395         GEM_BUG_ON(!i915_gem_object_has_pinned_pages(obj));
 396
 397         /* As we iterate forward through the sg, we record each entry in a
 398          * radixtree for quick repeated (backwards) lookups. If we have seen
 399          * this index previously, we will have an entry for it.
 400          *
 401          * Initial lookup is O(N), but this is amortized to O(1) for
 402          * sequential page access (where each new request is consecutive
 403          * to the previous one). Repeated lookups are O(lg(obj->base.size)),
 404          * i.e. O(1) with a large constant!
 405          */
 406         if (n < READ_ONCE(iter->sg_idx))
 407                 goto lookup;
 408
 409         mutex_lock(&iter->lock);
 410
 411         /* We prefer to reuse the last sg so that repeated lookup of this
 412          * (or the subsequent) sg are fast - comparing against the last
 413          * sg is faster than going through the radixtree.
 414          */
 415
 416         sg = iter->sg_pos;
 417         idx = iter->sg_idx;
 418         count = __sg_page_count(sg);
 419
 420         while (idx + count <= n) {
 421                 void *entry;
 422                 unsigned long i;
 423                 int ret;
 424
 425                 /* If we cannot allocate and insert this entry, or the
 426                  * individual pages from this range, cancel updating the
 427                  * sg_idx so that on this lookup we are forced to linearly
 428                  * scan onwards, but on future lookups we will try the
 429                  * insertion again (in which case we need to be careful of
 430                  * the error return reporting that we have already inserted
 431                  * this index).
 432                  */
 433                 ret = radix_tree_insert(&iter->radix, idx, sg);
 434                 if (ret && ret != -EEXIST)
 435                         goto scan;
 436
 437                 entry = xa_mk_value(idx);
 438                 for (i = 1; i < count; i++) {
 439                         ret = radix_tree_insert(&iter->radix, idx + i, entry);
 440                         if (ret && ret != -EEXIST)
 441                                 goto scan;
 442                 }
 443
 444                 idx += count;
 445                 sg = ____sg_next(sg);
 446                 count = __sg_page_count(sg);
 447         }
 448
 449 scan:
 450         iter->sg_pos = sg;
 451         iter->sg_idx = idx;
 452
 453         mutex_unlock(&iter->lock);
 454
 455         if (unlikely(n < idx)) /* insertion completed by another thread */
 456                 goto lookup;
 457
 458         /* In case we failed to insert the entry into the radixtree, we need
 459          * to look beyond the current sg.
 460          */
 461         while (idx + count <= n) {
 462                 idx += count;
 463                 sg = ____sg_next(sg);
 464                 count = __sg_page_count(sg);
 465         }
 466
 467         *offset = n - idx;
 468         return sg;
 469
 470 lookup:
 471         rcu_read_lock();
 472
 473         sg = radix_tree_lookup(&iter->radix, n);
 474         GEM_BUG_ON(!sg);
 475
 476         /* If this index is in the middle of multi-page sg entry,
 477          * the radix tree will contain a value entry that points
 478          * to the start of that range. We will return the pointer to
 479          * the base page and the offset of this page within the
 480          * sg entry's range.
 481          */
 482         *offset = 0;
 483         if (unlikely(xa_is_value(sg))) {
 484                 unsigned long base = xa_to_value(sg);
 485
 486                 sg = radix_tree_lookup(&iter->radix, base);
 487                 GEM_BUG_ON(!sg);
 488
 489                 *offset = n - base;
 490         }
 491
 492         rcu_read_unlock();
 493
 494         return sg;
 495 }
 496
 497 struct page *
 498 i915_gem_object_get_page(struct drm_i915_gem_object *obj, unsigned int n)
 499 {
 500         struct scatterlist *sg;
 501         unsigned int offset;
 502
 503         GEM_BUG_ON(!i915_gem_object_has_struct_page(obj));
 504
 505         sg = i915_gem_object_get_sg(obj, n, &offset);
 506         return nth_page(sg_page(sg), offset);
 507 }
 508
 509 /* Like i915_gem_object_get_page(), but mark the returned page dirty */
 510 struct page *
 511 i915_gem_object_get_dirty_page(struct drm_i915_gem_object *obj,
 512                                unsigned int n)
 513 {
 514         struct page *page;
 515
 516         page = i915_gem_object_get_page(obj, n);
 517         if (!obj->mm.dirty)
 518                 set_page_dirty(page);
 519
 520         return page;
 521 }
 522
 523 dma_addr_t
 524 i915_gem_object_get_dma_address_len(struct drm_i915_gem_object *obj,
 525                                     unsigned long n,
 526                                     unsigned int *len)
 527 {
 528         struct scatterlist *sg;
 529         unsigned int offset;
 530
 531         sg = i915_gem_object_get_sg(obj, n, &offset);
 532
 533         if (len)
 534                 *len = sg_dma_len(sg) - (offset << PAGE_SHIFT);
 535
 536         return sg_dma_address(sg) + (offset << PAGE_SHIFT);
 537 }
 538
 539 dma_addr_t
 540 i915_gem_object_get_dma_address(struct drm_i915_gem_object *obj,
 541                                 unsigned long n)
 542 {
 543         return i915_gem_object_get_dma_address_len(obj, n, NULL);
 544 }