1 // SPDX-License-Identifier: GPL-2.0+
3 #include <linux/dma-buf.h>
4 #include <linux/shmem_fs.h>
5 #include <linux/vmalloc.h>
6 #include <drm/drm_prime.h>
10 static struct vkms_gem_object *__vkms_gem_create(struct drm_device *dev,
13 struct vkms_gem_object *obj;
16 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
18 return ERR_PTR(-ENOMEM);
20 size = roundup(size, PAGE_SIZE);
21 ret = drm_gem_object_init(dev, &obj->gem, size);
27 mutex_init(&obj->pages_lock);
32 void vkms_gem_free_object(struct drm_gem_object *obj)
34 struct vkms_gem_object *gem = container_of(obj, struct vkms_gem_object,
40 mutex_destroy(&gem->pages_lock);
41 drm_gem_object_release(obj);
45 vm_fault_t vkms_gem_fault(struct vm_fault *vmf)
47 struct vm_area_struct *vma = vmf->vma;
48 struct vkms_gem_object *obj = vma->vm_private_data;
49 unsigned long vaddr = vmf->address;
52 vm_fault_t ret = VM_FAULT_SIGBUS;
54 page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
55 num_pages = DIV_ROUND_UP(obj->gem.size, PAGE_SIZE);
57 if (page_offset > num_pages)
58 return VM_FAULT_SIGBUS;
60 mutex_lock(&obj->pages_lock);
62 get_page(obj->pages[page_offset]);
63 vmf->page = obj->pages[page_offset];
66 mutex_unlock(&obj->pages_lock);
69 struct address_space *mapping;
71 mapping = file_inode(obj->gem.filp)->i_mapping;
72 page = shmem_read_mapping_page(mapping, page_offset);
78 switch (PTR_ERR(page)) {
88 ret = VM_FAULT_SIGBUS;
91 WARN_ON(PTR_ERR(page));
92 ret = VM_FAULT_SIGBUS;
100 static struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
101 struct drm_file *file,
105 struct vkms_gem_object *obj;
108 if (!file || !dev || !handle)
109 return ERR_PTR(-EINVAL);
111 obj = __vkms_gem_create(dev, size);
113 return ERR_CAST(obj);
115 ret = drm_gem_handle_create(file, &obj->gem, handle);
122 int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
123 struct drm_mode_create_dumb *args)
125 struct drm_gem_object *gem_obj;
128 if (!args || !dev || !file)
131 pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
132 size = pitch * args->height;
137 gem_obj = vkms_gem_create(dev, file, &args->handle, size);
139 return PTR_ERR(gem_obj);
141 args->size = gem_obj->size;
144 drm_gem_object_put(gem_obj);
146 DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
151 static struct page **_get_pages(struct vkms_gem_object *vkms_obj)
153 struct drm_gem_object *gem_obj = &vkms_obj->gem;
155 if (!vkms_obj->pages) {
156 struct page **pages = drm_gem_get_pages(gem_obj);
161 if (cmpxchg(&vkms_obj->pages, NULL, pages))
162 drm_gem_put_pages(gem_obj, pages, false, true);
165 return vkms_obj->pages;
168 void vkms_gem_vunmap(struct drm_gem_object *obj)
170 struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
172 mutex_lock(&vkms_obj->pages_lock);
173 if (vkms_obj->vmap_count < 1) {
174 WARN_ON(vkms_obj->vaddr);
175 WARN_ON(vkms_obj->pages);
176 mutex_unlock(&vkms_obj->pages_lock);
180 vkms_obj->vmap_count--;
182 if (vkms_obj->vmap_count == 0) {
183 vunmap(vkms_obj->vaddr);
184 vkms_obj->vaddr = NULL;
185 drm_gem_put_pages(obj, vkms_obj->pages, false, true);
186 vkms_obj->pages = NULL;
189 mutex_unlock(&vkms_obj->pages_lock);
192 int vkms_gem_vmap(struct drm_gem_object *obj)
194 struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
197 mutex_lock(&vkms_obj->pages_lock);
199 if (!vkms_obj->vaddr) {
200 unsigned int n_pages = obj->size >> PAGE_SHIFT;
201 struct page **pages = _get_pages(vkms_obj);
204 ret = PTR_ERR(pages);
208 vkms_obj->vaddr = vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
209 if (!vkms_obj->vaddr)
213 vkms_obj->vmap_count++;
218 drm_gem_put_pages(obj, vkms_obj->pages, false, true);
219 vkms_obj->pages = NULL;
221 mutex_unlock(&vkms_obj->pages_lock);
225 struct drm_gem_object *
226 vkms_prime_import_sg_table(struct drm_device *dev,
227 struct dma_buf_attachment *attach,
230 struct vkms_gem_object *obj;
233 obj = __vkms_gem_create(dev, attach->dmabuf->size);
235 return ERR_CAST(obj);
237 npages = PAGE_ALIGN(attach->dmabuf->size) / PAGE_SIZE;
238 DRM_DEBUG_PRIME("Importing %d pages\n", npages);
240 obj->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
242 vkms_gem_free_object(&obj->gem);
243 return ERR_PTR(-ENOMEM);
246 drm_prime_sg_to_page_addr_arrays(sg, obj->pages, NULL, npages);