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 (is_swiotlb_active(obj->base.dev->dev)) { 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_IS_SHRINKABLE, 142 .get_pages = i915_gem_object_get_pages_internal, 143 .put_pages = i915_gem_object_put_pages_internal, 144 }; 145 146 /** 147 * i915_gem_object_create_internal: create an object with volatile pages 148 * @i915: the i915 device 149 * @size: the size in bytes of backing storage to allocate for the object 150 * 151 * Creates a new object that wraps some internal memory for private use. 152 * This object is not backed by swappable storage, and as such its contents 153 * are volatile and only valid whilst pinned. If the object is reaped by the 154 * shrinker, its pages and data will be discarded. Equally, it is not a full 155 * GEM object and so not valid for access from userspace. This makes it useful 156 * for hardware interfaces like ringbuffers (which are pinned from the time 157 * the request is written to the time the hardware stops accessing it), but 158 * not for contexts (which need to be preserved when not active for later 159 * reuse). Note that it is not cleared upon allocation. 160 */ 161 struct drm_i915_gem_object * 162 i915_gem_object_create_internal(struct drm_i915_private *i915, 163 phys_addr_t size) 164 { 165 static struct lock_class_key lock_class; 166 struct drm_i915_gem_object *obj; 167 unsigned int cache_level; 168 169 GEM_BUG_ON(!size); 170 GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE)); 171 172 if (overflows_type(size, obj->base.size)) 173 return ERR_PTR(-E2BIG); 174 175 obj = i915_gem_object_alloc(); 176 if (!obj) 177 return ERR_PTR(-ENOMEM); 178 179 drm_gem_private_object_init(&i915->drm, &obj->base, size); 180 i915_gem_object_init(obj, &i915_gem_object_internal_ops, &lock_class, 0); 181 obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE; 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 } 200