1/*
2 * SPDX-License-Identifier: MIT
3 *
4 * Copyright © 2016 Intel Corporation
5 */
6
7#include "i915_scatterlist.h"
8
9#include "huge_gem_object.h"
10
11static void huge_free_pages(struct drm_i915_gem_object *obj,
12 struct sg_table *pages)
13{
14 unsigned long nreal = obj->scratch / PAGE_SIZE;
15 struct sgt_iter sgt_iter;
16 struct page *page;
17
18 for_each_sgt_page(page, sgt_iter, pages) {
19 __free_page(page);
20 if (!--nreal)
21 break;
22 }
23
24 sg_free_table(pages);
25 kfree(objp: pages);
26}
27
28static int huge_get_pages(struct drm_i915_gem_object *obj)
29{
30#define GFP (GFP_KERNEL | __GFP_NOWARN | __GFP_RETRY_MAYFAIL)
31 const unsigned long nreal = obj->scratch / PAGE_SIZE;
32 unsigned int npages; /* restricted by sg_alloc_table */
33 struct scatterlist *sg, *src, *end;
34 struct sg_table *pages;
35 unsigned long n;
36
37 if (overflows_type(obj->base.size / PAGE_SIZE, npages))
38 return -E2BIG;
39
40 npages = obj->base.size / PAGE_SIZE;
41 pages = kmalloc(sizeof(*pages), GFP);
42 if (!pages)
43 return -ENOMEM;
44
45 if (sg_alloc_table(pages, npages, GFP)) {
46 kfree(objp: pages);
47 return -ENOMEM;
48 }
49
50 sg = pages->sgl;
51 for (n = 0; n < nreal; n++) {
52 struct page *page;
53
54 page = alloc_page(GFP | __GFP_HIGHMEM);
55 if (!page) {
56 sg_mark_end(sg);
57 goto err;
58 }
59
60 sg_set_page(sg, page, PAGE_SIZE, offset: 0);
61 sg = __sg_next(sg);
62 }
63 if (nreal < npages) {
64 for (end = sg, src = pages->sgl; sg; sg = __sg_next(sg)) {
65 sg_set_page(sg, page: sg_page(sg: src), PAGE_SIZE, offset: 0);
66 src = __sg_next(sg: src);
67 if (src == end)
68 src = pages->sgl;
69 }
70 }
71
72 if (i915_gem_gtt_prepare_pages(obj, pages))
73 goto err;
74
75 __i915_gem_object_set_pages(obj, pages);
76
77 return 0;
78
79err:
80 huge_free_pages(obj, pages);
81 return -ENOMEM;
82#undef GFP
83}
84
85static void huge_put_pages(struct drm_i915_gem_object *obj,
86 struct sg_table *pages)
87{
88 i915_gem_gtt_finish_pages(obj, pages);
89 huge_free_pages(obj, pages);
90
91 obj->mm.dirty = false;
92}
93
94static const struct drm_i915_gem_object_ops huge_ops = {
95 .name = "huge-gem",
96 .get_pages = huge_get_pages,
97 .put_pages = huge_put_pages,
98};
99
100struct drm_i915_gem_object *
101huge_gem_object(struct drm_i915_private *i915,
102 phys_addr_t phys_size,
103 dma_addr_t dma_size)
104{
105 static struct lock_class_key lock_class;
106 struct drm_i915_gem_object *obj;
107 unsigned int cache_level;
108
109 GEM_BUG_ON(!phys_size || phys_size > dma_size);
110 GEM_BUG_ON(!IS_ALIGNED(phys_size, PAGE_SIZE));
111 GEM_BUG_ON(!IS_ALIGNED(dma_size, I915_GTT_PAGE_SIZE));
112
113 if (overflows_type(dma_size, obj->base.size))
114 return ERR_PTR(error: -E2BIG);
115
116 obj = i915_gem_object_alloc();
117 if (!obj)
118 return ERR_PTR(error: -ENOMEM);
119
120 drm_gem_private_object_init(dev: &i915->drm, obj: &obj->base, size: dma_size);
121 i915_gem_object_init(obj, ops: &huge_ops, key: &lock_class, flags: 0);
122 obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE;
123
124 obj->read_domains = I915_GEM_DOMAIN_CPU;
125 obj->write_domain = I915_GEM_DOMAIN_CPU;
126 cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
127 i915_gem_object_set_cache_coherency(obj, cache_level);
128 obj->scratch = phys_size;
129
130 return obj;
131}
132

source code of linux/drivers/gpu/drm/i915/gem/selftests/huge_gem_object.c