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