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
10 #include "i915_drv.h"
11 #include "i915_gem.h"
12 #include "i915_gem_internal.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
internal_free_pages(struct sg_table * st)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
i915_gem_object_get_pages_internal(struct drm_i915_gem_object * obj)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 npages; /* restricted by sg_alloc_table */
39 int max_order = MAX_ORDER;
40 unsigned int max_segment;
41 gfp_t gfp;
42
43 if (overflows_type(obj->base.size >> PAGE_SHIFT, npages))
44 return -E2BIG;
45
46 npages = obj->base.size >> PAGE_SHIFT;
47 max_segment = i915_sg_segment_size(i915->drm.dev) >> PAGE_SHIFT;
48 max_order = min(max_order, get_order(max_segment));
49
50 gfp = GFP_KERNEL | __GFP_HIGHMEM | __GFP_RECLAIMABLE;
51 if (IS_I965GM(i915) || IS_I965G(i915)) {
52 /* 965gm cannot relocate objects above 4GiB. */
53 gfp &= ~__GFP_HIGHMEM;
54 gfp |= __GFP_DMA32;
55 }
56
57 create_st:
58 st = kmalloc(sizeof(*st), GFP_KERNEL);
59 if (!st)
60 return -ENOMEM;
61
62 if (sg_alloc_table(st, npages, GFP_KERNEL)) {
63 kfree(st);
64 return -ENOMEM;
65 }
66
67 sg = st->sgl;
68 st->nents = 0;
69
70 do {
71 int order = min(fls(npages) - 1, max_order);
72 struct page *page;
73
74 do {
75 page = alloc_pages(gfp | (order ? QUIET : MAYFAIL),
76 order);
77 if (page)
78 break;
79 if (!order--)
80 goto err;
81
82 /* Limit subsequent allocations as well */
83 max_order = order;
84 } while (1);
85
86 sg_set_page(sg, page, PAGE_SIZE << order, 0);
87 st->nents++;
88
89 npages -= 1 << order;
90 if (!npages) {
91 sg_mark_end(sg);
92 break;
93 }
94
95 sg = __sg_next(sg);
96 } while (1);
97
98 if (i915_gem_gtt_prepare_pages(obj, st)) {
99 /* Failed to dma-map try again with single page sg segments */
100 if (get_order(st->sgl->length)) {
101 internal_free_pages(st);
102 max_order = 0;
103 goto create_st;
104 }
105 goto err;
106 }
107
108 __i915_gem_object_set_pages(obj, st);
109
110 return 0;
111
112 err:
113 sg_set_page(sg, NULL, 0, 0);
114 sg_mark_end(sg);
115 internal_free_pages(st);
116
117 return -ENOMEM;
118 }
119
i915_gem_object_put_pages_internal(struct drm_i915_gem_object * obj,struct sg_table * pages)120 static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,
121 struct sg_table *pages)
122 {
123 i915_gem_gtt_finish_pages(obj, pages);
124 internal_free_pages(pages);
125
126 obj->mm.dirty = false;
127
128 __start_cpu_write(obj);
129 }
130
131 static const struct drm_i915_gem_object_ops i915_gem_object_internal_ops = {
132 .name = "i915_gem_object_internal",
133 .flags = I915_GEM_OBJECT_IS_SHRINKABLE,
134 .get_pages = i915_gem_object_get_pages_internal,
135 .put_pages = i915_gem_object_put_pages_internal,
136 };
137
138 struct drm_i915_gem_object *
__i915_gem_object_create_internal(struct drm_i915_private * i915,const struct drm_i915_gem_object_ops * ops,phys_addr_t size)139 __i915_gem_object_create_internal(struct drm_i915_private *i915,
140 const struct drm_i915_gem_object_ops *ops,
141 phys_addr_t size)
142 {
143 static struct lock_class_key lock_class;
144 struct drm_i915_gem_object *obj;
145 unsigned int cache_level;
146
147 GEM_BUG_ON(!size);
148 GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));
149
150 if (overflows_type(size, obj->base.size))
151 return ERR_PTR(-E2BIG);
152
153 obj = i915_gem_object_alloc();
154 if (!obj)
155 return ERR_PTR(-ENOMEM);
156
157 drm_gem_private_object_init(&i915->drm, &obj->base, size);
158 i915_gem_object_init(obj, ops, &lock_class, 0);
159 obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE;
160
161 /*
162 * Mark the object as volatile, such that the pages are marked as
163 * dontneed whilst they are still pinned. As soon as they are unpinned
164 * they are allowed to be reaped by the shrinker, and the caller is
165 * expected to repopulate - the contents of this object are only valid
166 * whilst active and pinned.
167 */
168 i915_gem_object_set_volatile(obj);
169
170 obj->read_domains = I915_GEM_DOMAIN_CPU;
171 obj->write_domain = I915_GEM_DOMAIN_CPU;
172
173 cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
174 i915_gem_object_set_cache_coherency(obj, cache_level);
175
176 return obj;
177 }
178
179 /**
180 * i915_gem_object_create_internal: create an object with volatile pages
181 * @i915: the i915 device
182 * @size: the size in bytes of backing storage to allocate for the object
183 *
184 * Creates a new object that wraps some internal memory for private use.
185 * This object is not backed by swappable storage, and as such its contents
186 * are volatile and only valid whilst pinned. If the object is reaped by the
187 * shrinker, its pages and data will be discarded. Equally, it is not a full
188 * GEM object and so not valid for access from userspace. This makes it useful
189 * for hardware interfaces like ringbuffers (which are pinned from the time
190 * the request is written to the time the hardware stops accessing it), but
191 * not for contexts (which need to be preserved when not active for later
192 * reuse). Note that it is not cleared upon allocation.
193 */
194 struct drm_i915_gem_object *
i915_gem_object_create_internal(struct drm_i915_private * i915,phys_addr_t size)195 i915_gem_object_create_internal(struct drm_i915_private *i915,
196 phys_addr_t size)
197 {
198 return __i915_gem_object_create_internal(i915, &i915_gem_object_internal_ops, size);
199 }
200