1 // SPDX-License-Identifier: GPL-2.0+
3 #include <linux/shmem_fs.h>
7 static struct vkms_gem_object *__vkms_gem_create(struct drm_device *dev,
10 struct vkms_gem_object *obj;
13 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
15 return ERR_PTR(-ENOMEM);
17 size = roundup(size, PAGE_SIZE);
18 ret = drm_gem_object_init(dev, &obj->gem, size);
24 mutex_init(&obj->pages_lock);
29 void vkms_gem_free_object(struct drm_gem_object *obj)
31 struct vkms_gem_object *gem = container_of(obj, struct vkms_gem_object,
37 mutex_destroy(&gem->pages_lock);
38 drm_gem_object_release(obj);
42 vm_fault_t vkms_gem_fault(struct vm_fault *vmf)
44 struct vm_area_struct *vma = vmf->vma;
45 struct vkms_gem_object *obj = vma->vm_private_data;
46 unsigned long vaddr = vmf->address;
49 vm_fault_t ret = VM_FAULT_SIGBUS;
51 page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
52 num_pages = DIV_ROUND_UP(obj->gem.size, PAGE_SIZE);
54 if (page_offset > num_pages)
55 return VM_FAULT_SIGBUS;
57 mutex_lock(&obj->pages_lock);
59 get_page(obj->pages[page_offset]);
60 vmf->page = obj->pages[page_offset];
63 mutex_unlock(&obj->pages_lock);
66 struct address_space *mapping;
68 mapping = file_inode(obj->gem.filp)->i_mapping;
69 page = shmem_read_mapping_page(mapping, page_offset);
75 switch (PTR_ERR(page)) {
85 ret = VM_FAULT_SIGBUS;
88 WARN_ON(PTR_ERR(page));
89 ret = VM_FAULT_SIGBUS;
97 struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
98 struct drm_file *file,
102 struct vkms_gem_object *obj;
105 if (!file || !dev || !handle)
106 return ERR_PTR(-EINVAL);
108 obj = __vkms_gem_create(dev, size);
110 return ERR_CAST(obj);
112 ret = drm_gem_handle_create(file, &obj->gem, handle);
113 drm_gem_object_put_unlocked(&obj->gem);
120 int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
121 struct drm_mode_create_dumb *args)
123 struct drm_gem_object *gem_obj;
126 if (!args || !dev || !file)
129 pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
130 size = pitch * args->height;
135 gem_obj = vkms_gem_create(dev, file, &args->handle, size);
137 return PTR_ERR(gem_obj);
139 args->size = gem_obj->size;
142 DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
147 static struct page **_get_pages(struct vkms_gem_object *vkms_obj)
149 struct drm_gem_object *gem_obj = &vkms_obj->gem;
151 if (!vkms_obj->pages) {
152 struct page **pages = drm_gem_get_pages(gem_obj);
157 if (cmpxchg(&vkms_obj->pages, NULL, pages))
158 drm_gem_put_pages(gem_obj, pages, false, true);
161 return vkms_obj->pages;
164 void vkms_gem_vunmap(struct drm_gem_object *obj)
166 struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
168 mutex_lock(&vkms_obj->pages_lock);
169 if (vkms_obj->vmap_count < 1) {
170 WARN_ON(vkms_obj->vaddr);
171 WARN_ON(vkms_obj->pages);
172 mutex_unlock(&vkms_obj->pages_lock);
176 vkms_obj->vmap_count--;
178 if (vkms_obj->vmap_count == 0) {
179 vunmap(vkms_obj->vaddr);
180 vkms_obj->vaddr = NULL;
181 drm_gem_put_pages(obj, vkms_obj->pages, false, true);
182 vkms_obj->pages = NULL;
185 mutex_unlock(&vkms_obj->pages_lock);
188 int vkms_gem_vmap(struct drm_gem_object *obj)
190 struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
193 mutex_lock(&vkms_obj->pages_lock);
195 if (!vkms_obj->vaddr) {
196 unsigned int n_pages = obj->size >> PAGE_SHIFT;
197 struct page **pages = _get_pages(vkms_obj);
200 ret = PTR_ERR(pages);
204 vkms_obj->vaddr = vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
205 if (!vkms_obj->vaddr)
209 vkms_obj->vmap_count++;
214 drm_gem_put_pages(obj, vkms_obj->pages, false, true);
215 vkms_obj->pages = NULL;
217 mutex_unlock(&vkms_obj->pages_lock);