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 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
7 */
8
9#include <linux/shmem_fs.h>
10
11#include "vkms_drv.h"
12
13static struct vkms_gem_object *__vkms_gem_create(struct drm_device *dev,
14 u64 size)
15{
16 struct vkms_gem_object *obj;
17 int ret;
18
19 obj = kzalloc(sizeof(*obj), GFP_KERNEL);
20 if (!obj)
21 return ERR_PTR(-ENOMEM);
22
23 size = roundup(size, PAGE_SIZE);
24 ret = drm_gem_object_init(dev, &obj->gem, size);
25 if (ret) {
26 kfree(obj);
27 return ERR_PTR(ret);
28 }
29
30 mutex_init(&obj->pages_lock);
31
32 return obj;
33}
34
35void vkms_gem_free_object(struct drm_gem_object *obj)
36{
37 struct vkms_gem_object *gem = container_of(obj, struct vkms_gem_object,
38 gem);
39
40 WARN_ON(gem->pages);
41 WARN_ON(gem->vaddr);
42
43 mutex_destroy(&gem->pages_lock);
44 drm_gem_object_release(obj);
45 kfree(gem);
46}
47
48vm_fault_t vkms_gem_fault(struct vm_fault *vmf)
49{
50 struct vm_area_struct *vma = vmf->vma;
51 struct vkms_gem_object *obj = vma->vm_private_data;
52 unsigned long vaddr = vmf->address;
53 pgoff_t page_offset;
54 loff_t num_pages;
55 vm_fault_t ret = VM_FAULT_SIGBUS;
56
57 page_offset = (vaddr - vma->vm_start) >> PAGE_SHIFT;
58 num_pages = DIV_ROUND_UP(obj->gem.size, PAGE_SIZE);
59
60 if (page_offset > num_pages)
61 return VM_FAULT_SIGBUS;
62
63 mutex_lock(&obj->pages_lock);
64 if (obj->pages) {
65 get_page(obj->pages[page_offset]);
66 vmf->page = obj->pages[page_offset];
67 ret = 0;
68 }
69 mutex_unlock(&obj->pages_lock);
70 if (ret) {
71 struct page *page;
72 struct address_space *mapping;
73
74 mapping = file_inode(obj->gem.filp)->i_mapping;
75 page = shmem_read_mapping_page(mapping, page_offset);
76
77 if (!IS_ERR(page)) {
78 vmf->page = page;
79 ret = 0;
80 } else {
81 switch (PTR_ERR(page)) {
82 case -ENOSPC:
83 case -ENOMEM:
84 ret = VM_FAULT_OOM;
85 break;
86 case -EBUSY:
87 ret = VM_FAULT_RETRY;
88 break;
89 case -EFAULT:
90 case -EINVAL:
91 ret = VM_FAULT_SIGBUS;
92 break;
93 default:
94 WARN_ON(PTR_ERR(page));
95 ret = VM_FAULT_SIGBUS;
96 break;
97 }
98 }
99 }
100 return ret;
101}
102
103struct drm_gem_object *vkms_gem_create(struct drm_device *dev,
104 struct drm_file *file,
105 u32 *handle,
106 u64 size)
107{
108 struct vkms_gem_object *obj;
109 int ret;
110
111 if (!file || !dev || !handle)
112 return ERR_PTR(-EINVAL);
113
114 obj = __vkms_gem_create(dev, size);
115 if (IS_ERR(obj))
116 return ERR_CAST(obj);
117
118 ret = drm_gem_handle_create(file, &obj->gem, handle);
119 drm_gem_object_put_unlocked(&obj->gem);
120 if (ret) {
121 drm_gem_object_release(&obj->gem);
122 kfree(obj);
123 return ERR_PTR(ret);
124 }
125
126 return &obj->gem;
127}
128
129int vkms_dumb_create(struct drm_file *file, struct drm_device *dev,
130 struct drm_mode_create_dumb *args)
131{
132 struct drm_gem_object *gem_obj;
133 u64 pitch, size;
134
135 if (!args || !dev || !file)
136 return -EINVAL;
137
138 pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
139 size = pitch * args->height;
140
141 if (!size)
142 return -EINVAL;
143
144 gem_obj = vkms_gem_create(dev, file, &args->handle, size);
145 if (IS_ERR(gem_obj))
146 return PTR_ERR(gem_obj);
147
148 args->size = gem_obj->size;
149 args->pitch = pitch;
150
151 DRM_DEBUG_DRIVER("Created object of size %lld\n", size);
152
153 return 0;
154}
155
156static struct page **_get_pages(struct vkms_gem_object *vkms_obj)
157{
158 struct drm_gem_object *gem_obj = &vkms_obj->gem;
159
160 if (!vkms_obj->pages) {
161 struct page **pages = drm_gem_get_pages(gem_obj);
162
163 if (IS_ERR(pages))
164 return pages;
165
166 if (cmpxchg(&vkms_obj->pages, NULL, pages))
167 drm_gem_put_pages(gem_obj, pages, false, true);
168 }
169
170 return vkms_obj->pages;
171}
172
173void vkms_gem_vunmap(struct drm_gem_object *obj)
174{
175 struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
176
177 mutex_lock(&vkms_obj->pages_lock);
178 if (vkms_obj->vmap_count < 1) {
179 WARN_ON(vkms_obj->vaddr);
180 WARN_ON(vkms_obj->pages);
181 mutex_unlock(&vkms_obj->pages_lock);
182 return;
183 }
184
185 vkms_obj->vmap_count--;
186
187 if (vkms_obj->vmap_count == 0) {
188 vunmap(vkms_obj->vaddr);
189 vkms_obj->vaddr = NULL;
190 drm_gem_put_pages(obj, vkms_obj->pages, false, true);
191 vkms_obj->pages = NULL;
192 }
193
194 mutex_unlock(&vkms_obj->pages_lock);
195}
196
197int vkms_gem_vmap(struct drm_gem_object *obj)
198{
199 struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(obj);
200 int ret = 0;
201
202 mutex_lock(&vkms_obj->pages_lock);
203
204 if (!vkms_obj->vaddr) {
205 unsigned int n_pages = obj->size >> PAGE_SHIFT;
206 struct page **pages = _get_pages(vkms_obj);
207
208 if (IS_ERR(pages)) {
209 ret = PTR_ERR(pages);
210 goto out;
211 }
212
213 vkms_obj->vaddr = vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);
214 if (!vkms_obj->vaddr)
215 goto err_vmap;
216 }
217
218 vkms_obj->vmap_count++;
219 goto out;
220
221err_vmap:
222 ret = -ENOMEM;
223 drm_gem_put_pages(obj, vkms_obj->pages, false, true);
224 vkms_obj->pages = NULL;
225out:
226 mutex_unlock(&vkms_obj->pages_lock);
227 return ret;
228}