1 // SPDX-License-Identifier: GPL-2.0+
2
3 #include <linux/shmem_fs.h>
4 #include <linux/vmalloc.h>
5
6 #include "vkms_drv.h"
7
__vkms_gem_create(struct drm_device * dev,u64 size)8 static struct vkms_gem_object *__vkms_gem_create(struct drm_device *dev,
9 u64 size)
10 {
11 struct vkms_gem_object *obj;
12 int ret;
13
14 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
15 if (!obj)
16 return ERR_PTR(-ENOMEM);
17
18 size = roundup(size, PAGE_SIZE);
19 ret = drm_gem_object_init(dev, &obj->gem, size);
20 if (ret) {
21 kfree(obj);
22 return ERR_PTR(ret);
23 }
24
25 mutex_init(&obj->pages_lock);
26
27 return obj;
28 }
29
vkms_gem_free_object(struct drm_gem_object * obj)30 void vkms_gem_free_object(struct drm_gem_object *obj)
31 {
32 struct vkms_gem_object *gem = container_of(obj, struct vkms_gem_object,
33 gem);
34
35 WARN_ON(gem->pages);
36 WARN_ON(gem->vaddr);
37
38 mutex_destroy(&gem->pages_lock);
39 drm_gem_object_release(obj);
40 kfree(gem);
41 }
42
vkms_gem_fault(struct vm_fault * vmf)43 vm_fault_t vkms_gem_fault(struct vm_fault *vmf)
44 {
45 struct vm_area_struct *vma = vmf->vma;
46 struct vkms_gem_object *obj = vma->vm_private_data;
47 unsigned long vaddr = vmf->address;
48 pgoff_t page_offset;
49 loff_t num_pages;
50 vm_fault_t ret = VM_FAULT_SIGBUS;
51
52 page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
53 num_pages = DIV_ROUND_UP(obj->gem.size, PAGE_SIZE);
54
55 if (page_offset > num_pages)
56 return VM_FAULT_SIGBUS;
57
58 mutex_lock(&obj->pages_lock);
59 if (obj->pages) {
60 get_page(obj->pages[page_offset]);
61 vmf->page = obj->pages[page_offset];
62 ret = 0;
63 }
64 mutex_unlock(&obj->pages_lock);
65 if (ret) {
66 struct page *page;
67 struct address_space *mapping;
68
69 mapping = file_inode(obj->gem.filp)->i_mapping;
70 page = shmem_read_mapping_page(mapping, page_offset);
71
72 if (!IS_ERR(page)) {
73 vmf->page = page;
74 ret = 0;
75 } else {
76 switch (PTR_ERR(page)) {
77 case -ENOSPC:
78 case -ENOMEM:
79 ret = VM_FAULT_OOM;
80 break;
81 case -EBUSY:
82 ret = VM_FAULT_RETRY;
83 break;
84 case -EFAULT:
85 case -EINVAL:
86 ret = VM_FAULT_SIGBUS;
87 break;
88 default:
89 WARN_ON(PTR_ERR(page));
90 ret = VM_FAULT_SIGBUS;
91 break;
92 }
93 }
94 }
95 return ret;
96 }
97
vkms_gem_create(struct drm_device * dev,struct drm_file * file,u32 * handle,u64 size)98 struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
99 struct drm_file *file,
100 u32 *handle,
101 u64 size)
102 {
103 struct vkms_gem_object *obj;
104 int ret;
105
106 if (!file || !dev || !handle)
107 return ERR_PTR(-EINVAL);
108
109 obj = __vkms_gem_create(dev, size);
110 if (IS_ERR(obj))
111 return ERR_CAST(obj);
112
113 ret = drm_gem_handle_create(file, &obj->gem, handle);
114 drm_gem_object_put_unlocked(&obj->gem);
115 if (ret)
116 return ERR_PTR(ret);
117
118 return &obj->gem;
119 }
120
vkms_dumb_create(struct drm_file * file,struct drm_device * dev,struct drm_mode_create_dumb * args)121 int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
122 struct drm_mode_create_dumb *args)
123 {
124 struct drm_gem_object *gem_obj;
125 u64 pitch, size;
126
127 if (!args || !dev || !file)
128 return -EINVAL;
129
130 pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
131 size = pitch * args->height;
132
133 if (!size)
134 return -EINVAL;
135
136 gem_obj = vkms_gem_create(dev, file, &args->handle, size);
137 if (IS_ERR(gem_obj))
138 return PTR_ERR(gem_obj);
139
140 args->size = gem_obj->size;
141 args->pitch = pitch;
142
143 DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
144
145 return 0;
146 }
147
_get_pages(struct vkms_gem_object * vkms_obj)148 static struct page **_get_pages(struct vkms_gem_object *vkms_obj)
149 {
150 struct drm_gem_object *gem_obj = &vkms_obj->gem;
151
152 if (!vkms_obj->pages) {
153 struct page **pages = drm_gem_get_pages(gem_obj);
154
155 if (IS_ERR(pages))
156 return pages;
157
158 if (cmpxchg(&vkms_obj->pages, NULL, pages))
159 drm_gem_put_pages(gem_obj, pages, false, true);
160 }
161
162 return vkms_obj->pages;
163 }
164
vkms_gem_vunmap(struct drm_gem_object * obj)165 void vkms_gem_vunmap(struct drm_gem_object *obj)
166 {
167 struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
168
169 mutex_lock(&vkms_obj->pages_lock);
170 if (vkms_obj->vmap_count < 1) {
171 WARN_ON(vkms_obj->vaddr);
172 WARN_ON(vkms_obj->pages);
173 mutex_unlock(&vkms_obj->pages_lock);
174 return;
175 }
176
177 vkms_obj->vmap_count--;
178
179 if (vkms_obj->vmap_count == 0) {
180 vunmap(vkms_obj->vaddr);
181 vkms_obj->vaddr = NULL;
182 drm_gem_put_pages(obj, vkms_obj->pages, false, true);
183 vkms_obj->pages = NULL;
184 }
185
186 mutex_unlock(&vkms_obj->pages_lock);
187 }
188
vkms_gem_vmap(struct drm_gem_object * obj)189 int vkms_gem_vmap(struct drm_gem_object *obj)
190 {
191 struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
192 int ret = 0;
193
194 mutex_lock(&vkms_obj->pages_lock);
195
196 if (!vkms_obj->vaddr) {
197 unsigned int n_pages = obj->size >> PAGE_SHIFT;
198 struct page **pages = _get_pages(vkms_obj);
199
200 if (IS_ERR(pages)) {
201 ret = PTR_ERR(pages);
202 goto out;
203 }
204
205 vkms_obj->vaddr = vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
206 if (!vkms_obj->vaddr)
207 goto err_vmap;
208 }
209
210 vkms_obj->vmap_count++;
211 goto out;
212
213 err_vmap:
214 ret = -ENOMEM;
215 drm_gem_put_pages(obj, vkms_obj->pages, false, true);
216 vkms_obj->pages = NULL;
217 out:
218 mutex_unlock(&vkms_obj->pages_lock);
219 return ret;
220 }
221
