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_object.h"
  14 #include "i915_scatterlist.h"
  15 #include "i915_utils.h"
  16
  17 #define QUIET (__GFP_NORETRY | __GFP_NOWARN)
  18 #define MAYFAIL (__GFP_RETRY_MAYFAIL | __GFP_NOWARN)
  19
  20 static void internal_free_pages(struct sg_table *st)
  21 {
  22         struct scatterlist *sg;
  23
  24         for (sg = st->sgl; sg; sg = __sg_next(sg)) {
  25                 if (sg_page(sg))
  26                         __free_pages(sg_page(sg), get_order(sg->length));
  27         }
  28
  29         sg_free_table(st);
  30         kfree(st);
  31 }
  32
  33 static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
  34 {
  35         struct drm_i915_private *i915 = to_i915(obj->base.dev);
  36         struct sg_table *st;
  37         struct scatterlist *sg;
  38         unsigned int sg_page_sizes;
  39         unsigned int npages;
  40         int max_order;
  41         gfp_t gfp;
  42
  43         max_order = MAX_ORDER;
  44 #ifdef CONFIG_SWIOTLB
  45         if (swiotlb_nr_tbl()) {
  46                 unsigned int max_segment;
  47
  48                 max_segment = swiotlb_max_segment();
  49                 if (max_segment) {
  50                         max_segment = max_t(unsigned int, max_segment,
  51                                             PAGE_SIZE) >> PAGE_SHIFT;
  52                         max_order = min(max_order, ilog2(max_segment));
  53                 }
  54         }
  55 #endif
  56
  57         gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_RECLAIMABLE;
  58         if (IS_I965GM(i915) || IS_I965G(i915)) {
  59                 /* 965gm cannot relocate objects above 4GiB. */
  60                 gfp &= ~__GFP_HIGHMEM;
  61                 gfp |= __GFP_DMA32;
  62         }
  63
  64 create_st:
  65         st = kmalloc(sizeof(*st), GFP_KERNEL);
  66         if (!st)
  67                 return -ENOMEM;
  68
  69         npages = obj->base.size / PAGE_SIZE;
  70         if (sg_alloc_table(st, npages, GFP_KERNEL)) {
  71                 kfree(st);
  72                 return -ENOMEM;
  73         }
  74
  75         sg = st->sgl;
  76         st->nents = 0;
  77         sg_page_sizes = 0;
  78
  79         do {
  80                 int order = min(fls(npages) - 1, max_order);
  81                 struct page *page;
  82
  83                 do {
  84                         page = alloc_pages(gfp | (order ? QUIET : MAYFAIL),
  85                                            order);
  86                         if (page)
  87                                 break;
  88                         if (!order--)
  89                                 goto err;
  90
  91                         /* Limit subsequent allocations as well */
  92                         max_order = order;
  93                 } while (1);
  94
  95                 sg_set_page(sg, page, PAGE_SIZE << order, 0);
  96                 sg_page_sizes |= PAGE_SIZE << order;
  97                 st->nents++;
  98
  99                 npages -= 1 << order;
 100                 if (!npages) {
 101                         sg_mark_end(sg);
 102                         break;
 103                 }
 104
 105                 sg = __sg_next(sg);
 106         } while (1);
 107
 108         if (i915_gem_gtt_prepare_pages(obj, st)) {
 109                 /* Failed to dma-map try again with single page sg segments */
 110                 if (get_order(st->sgl->length)) {
 111                         internal_free_pages(st);
 112                         max_order = 0;
 113                         goto create_st;
 114                 }
 115                 goto err;
 116         }
 117
 118         __i915_gem_object_set_pages(obj, st, sg_page_sizes);
 119
 120         return 0;
 121
 122 err:
 123         sg_set_page(sg, NULL, 0, 0);
 124         sg_mark_end(sg);
 125         internal_free_pages(st);
 126
 127         return -ENOMEM;
 128 }
 129
 130 static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
 131                                                struct sg_table *pages)
 132 {
 133         i915_gem_gtt_finish_pages(obj, pages);
 134         internal_free_pages(pages);
 135
 136         obj->mm.dirty = false;
 137 }
 138
 139 static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
 140         .name = "i915_gem_object_internal",
 141         .flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
 142                  I915_GEM_OBJECT_IS_SHRINKABLE,
 143         .get_pages = i915_gem_object_get_pages_internal,
 144         .put_pages = i915_gem_object_put_pages_internal,
 145 };
 146
 147 /**
 148  * i915_gem_object_create_internal: create an object with volatile pages
 149  * @i915: the i915 device
 150  * @size: the size in bytes of backing storage to allocate for the object
 151  *
 152  * Creates a new object that wraps some internal memory for private use.
 153  * This object is not backed by swappable storage, and as such its contents
 154  * are volatile and only valid whilst pinned. If the object is reaped by the
 155  * shrinker, its pages and data will be discarded. Equally, it is not a full
 156  * GEM object and so not valid for access from userspace. This makes it useful
 157  * for hardware interfaces like ringbuffers (which are pinned from the time
 158  * the request is written to the time the hardware stops accessing it), but
 159  * not for contexts (which need to be preserved when not active for later
 160  * reuse). Note that it is not cleared upon allocation.
 161  */
 162 struct drm_i915_gem_object *
 163 i915_gem_object_create_internal(struct drm_i915_private *i915,
 164                                 phys_addr_t size)
 165 {
 166         static struct lock_class_key lock_class;
 167         struct drm_i915_gem_object *obj;
 168         unsigned int cache_level;
 169
 170         GEM_BUG_ON(!size);
 171         GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));
 172
 173         if (overflows_type(size, obj->base.size))
 174                 return ERR_PTR(-E2BIG);
 175
 176         obj = i915_gem_object_alloc();
 177         if (!obj)
 178                 return ERR_PTR(-ENOMEM);
 179
 180         drm_gem_private_object_init(&i915->drm, &obj->base, size);
 181         i915_gem_object_init(obj, &i915_gem_object_internal_ops, &lock_class);
 182
 183         /*
 184          * Mark the object as volatile, such that the pages are marked as
 185          * dontneed whilst they are still pinned. As soon as they are unpinned
 186          * they are allowed to be reaped by the shrinker, and the caller is
 187          * expected to repopulate - the contents of this object are only valid
 188          * whilst active and pinned.
 189          */
 190         i915_gem_object_set_volatile(obj);
 191
 192         obj->read_domains = I915_GEM_DOMAIN_CPU;
 193         obj->write_domain = I915_GEM_DOMAIN_CPU;
 194
 195         cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
 196         i915_gem_object_set_cache_coherency(obj, cache_level);
 197
 198         return obj;
 199 }