drivers/gpu/drm/i915/gem/i915_gem_internal.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright © 2014-2016 Intel Corporation
   5  */
   6
   7 #include <linux/scatterlist.h>
   8 #include <linux/slab.h>
   9 #include <linux/swiotlb.h>
  10
  11 #include "i915_drv.h"
  12 #include "i915_gem.h"
  13 #include "i915_gem_internal.h"
  14 #include "i915_gem_object.h"
  15 #include "i915_scatterlist.h"
  16 #include "i915_utils.h"
  17
  18 #define QUIET (__GFP_NORETRY | __GFP_NOWARN)
  19 #define MAYFAIL (__GFP_RETRY_MAYFAIL | __GFP_NOWARN)
  20
  21 static void internal_free_pages(struct sg_table *st)
  22 {
  23         struct scatterlist *sg;
  24
  25         for (sg = st->sgl; sg; sg = __sg_next(sg)) {
  26                 if (sg_page(sg))
  27                         __free_pages(sg_page(sg), get_order(sg->length));
  28         }
  29
  30         sg_free_table(st);
  31         kfree(st);
  32 }
  33
  34 static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
  35 {
  36         struct drm_i915_private *i915 = to_i915(obj->base.dev);
  37         struct sg_table *st;
  38         struct scatterlist *sg;
  39         unsigned int sg_page_sizes;
  40         unsigned int npages;
  41         int max_order;
  42         gfp_t gfp;
  43
  44         max_order = MAX_ORDER;
  45 #ifdef CONFIG_SWIOTLB
  46         if (is_swiotlb_active(obj->base.dev->dev)) {
  47                 unsigned int max_segment;
  48
  49                 max_segment = swiotlb_max_segment();
  50                 if (max_segment) {
  51                         max_segment = max_t(unsigned int, max_segment,
  52                                             PAGE_SIZE) >> PAGE_SHIFT;
  53                         max_order = min(max_order, ilog2(max_segment));
  54                 }
  55         }
  56 #endif
  57
  58         gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_RECLAIMABLE;
  59         if (IS_I965GM(i915) || IS_I965G(i915)) {
  60                 /* 965gm cannot relocate objects above 4GiB. */
  61                 gfp &= ~__GFP_HIGHMEM;
  62                 gfp |= __GFP_DMA32;
  63         }
  64
  65 create_st:
  66         st = kmalloc(sizeof(*st), GFP_KERNEL);
  67         if (!st)
  68                 return -ENOMEM;
  69
  70         npages = obj->base.size / PAGE_SIZE;
  71         if (sg_alloc_table(st, npages, GFP_KERNEL)) {
  72                 kfree(st);
  73                 return -ENOMEM;
  74         }
  75
  76         sg = st->sgl;
  77         st->nents = 0;
  78         sg_page_sizes = 0;
  79
  80         do {
  81                 int order = min(fls(npages) - 1, max_order);
  82                 struct page *page;
  83
  84                 do {
  85                         page = alloc_pages(gfp | (order ? QUIET : MAYFAIL),
  86                                            order);
  87                         if (page)
  88                                 break;
  89                         if (!order--)
  90                                 goto err;
  91
  92                         /* Limit subsequent allocations as well */
  93                         max_order = order;
  94                 } while (1);
  95
  96                 sg_set_page(sg, page, PAGE_SIZE << order, 0);
  97                 sg_page_sizes |= PAGE_SIZE << order;
  98                 st->nents++;
  99
 100                 npages -= 1 << order;
 101                 if (!npages) {
 102                         sg_mark_end(sg);
 103                         break;
 104                 }
 105
 106                 sg = __sg_next(sg);
 107         } while (1);
 108
 109         if (i915_gem_gtt_prepare_pages(obj, st)) {
 110                 /* Failed to dma-map try again with single page sg segments */
 111                 if (get_order(st->sgl->length)) {
 112                         internal_free_pages(st);
 113                         max_order = 0;
 114                         goto create_st;
 115                 }
 116                 goto err;
 117         }
 118
 119         __i915_gem_object_set_pages(obj, st, sg_page_sizes);
 120
 121         return 0;
 122
 123 err:
 124         sg_set_page(sg, NULL, 0, 0);
 125         sg_mark_end(sg);
 126         internal_free_pages(st);
 127
 128         return -ENOMEM;
 129 }
 130
 131 static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
 132                                                struct sg_table *pages)
 133 {
 134         i915_gem_gtt_finish_pages(obj, pages);
 135         internal_free_pages(pages);
 136
 137         obj->mm.dirty = false;
 138
 139         __start_cpu_write(obj);
 140 }
 141
 142 static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
 143         .name = "i915_gem_object_internal",
 144         .flags = I915_GEM_OBJECT_IS_SHRINKABLE,
 145         .get_pages = i915_gem_object_get_pages_internal,
 146         .put_pages = i915_gem_object_put_pages_internal,
 147 };
 148
 149 struct drm_i915_gem_object *
 150 __i915_gem_object_create_internal(struct drm_i915_private *i915,
 151                                   const struct drm_i915_gem_object_ops *ops,
 152                                   phys_addr_t size)
 153 {
 154         static struct lock_class_key lock_class;
 155         struct drm_i915_gem_object *obj;
 156         unsigned int cache_level;
 157
 158         GEM_BUG_ON(!size);
 159         GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));
 160
 161         if (overflows_type(size, obj->base.size))
 162                 return ERR_PTR(-E2BIG);
 163
 164         obj = i915_gem_object_alloc();
 165         if (!obj)
 166                 return ERR_PTR(-ENOMEM);
 167
 168         drm_gem_private_object_init(&i915->drm, &obj->base, size);
 169         i915_gem_object_init(obj, ops, &lock_class, 0);
 170         obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE;
 171
 172         /*
 173          * Mark the object as volatile, such that the pages are marked as
 174          * dontneed whilst they are still pinned. As soon as they are unpinned
 175          * they are allowed to be reaped by the shrinker, and the caller is
 176          * expected to repopulate - the contents of this object are only valid
 177          * whilst active and pinned.
 178          */
 179         i915_gem_object_set_volatile(obj);
 180
 181         obj->read_domains = I915_GEM_DOMAIN_CPU;
 182         obj->write_domain = I915_GEM_DOMAIN_CPU;
 183
 184         cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
 185         i915_gem_object_set_cache_coherency(obj, cache_level);
 186
 187         return obj;
 188 }
 189
 190 /**
 191  * i915_gem_object_create_internal: create an object with volatile pages
 192  * @i915: the i915 device
 193  * @size: the size in bytes of backing storage to allocate for the object
 194  *
 195  * Creates a new object that wraps some internal memory for private use.
 196  * This object is not backed by swappable storage, and as such its contents
 197  * are volatile and only valid whilst pinned. If the object is reaped by the
 198  * shrinker, its pages and data will be discarded. Equally, it is not a full
 199  * GEM object and so not valid for access from userspace. This makes it useful
 200  * for hardware interfaces like ringbuffers (which are pinned from the time
 201  * the request is written to the time the hardware stops accessing it), but
 202  * not for contexts (which need to be preserved when not active for later
 203  * reuse). Note that it is not cleared upon allocation.
 204  */
 205 struct drm_i915_gem_object *
 206 i915_gem_object_create_internal(struct drm_i915_private *i915,
 207                                 phys_addr_t size)
 208 {
 209         return __i915_gem_object_create_internal(i915, &i915_gem_object_internal_ops, size);
 210 }