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
 20static 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
 33static 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_PAGE_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
 57create_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
112err:
113	sg_set_page(sg, NULL, 0, 0);
114	sg_mark_end(sg);
115	internal_free_pages(st);
116
117	return -ENOMEM;
118}
119
120static 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
131static 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
138struct drm_i915_gem_object *
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 */
194struct drm_i915_gem_object *
195i915_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}