1 /*
2  * \file drm_scatter.c
3  * IOCTLs to manage scatter/gather memory
4  *
5  * \author Gareth Hughes <gareth@valinux.com>
6  */
7 
8 /*
9  * Created: Mon Dec 18 23:20:54 2000 by gareth@valinux.com
10  *
11  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
12  * All Rights Reserved.
13  *
14  * Permission is hereby granted, free of charge, to any person obtaining a
15  * copy of this software and associated documentation files (the "Software"),
16  * to deal in the Software without restriction, including without limitation
17  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
18  * and/or sell copies of the Software, and to permit persons to whom the
19  * Software is furnished to do so, subject to the following conditions:
20  *
21  * The above copyright notice and this permission notice (including the next
22  * paragraph) shall be included in all copies or substantial portions of the
23  * Software.
24  *
25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
26  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
27  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
28  * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
29  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
30  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
31  * DEALINGS IN THE SOFTWARE.
32  */
33 
34 #include <linux/mm.h>
35 #include <linux/slab.h>
36 #include <linux/vmalloc.h>
37 
38 #include <drm/drm.h>
39 #include <drm/drm_drv.h>
40 #include <drm/drm_print.h>
41 
42 #include "drm_legacy.h"
43 
44 #define DEBUG_SCATTER 0
45 
drm_sg_cleanup(struct drm_sg_mem * entry)46 static void drm_sg_cleanup(struct drm_sg_mem * entry)
47 {
48 	struct page *page;
49 	int i;
50 
51 	for (i = 0; i < entry->pages; i++) {
52 		page = entry->pagelist[i];
53 		if (page)
54 			ClearPageReserved(page);
55 	}
56 
57 	vfree(entry->virtual);
58 
59 	kfree(entry->busaddr);
60 	kfree(entry->pagelist);
61 	kfree(entry);
62 }
63 
drm_legacy_sg_cleanup(struct drm_device * dev)64 void drm_legacy_sg_cleanup(struct drm_device *dev)
65 {
66 	if (drm_core_check_feature(dev, DRIVER_SG) && dev->sg &&
67 	    drm_core_check_feature(dev, DRIVER_LEGACY)) {
68 		drm_sg_cleanup(dev->sg);
69 		dev->sg = NULL;
70 	}
71 }
72 #ifdef _LP64
73 # define ScatterHandle(x) (unsigned int)((x >> 32) + (x & ((1L << 32) - 1)))
74 #else
75 # define ScatterHandle(x) (unsigned int)(x)
76 #endif
77 
drm_legacy_sg_alloc(struct drm_device * dev,void * data,struct drm_file * file_priv)78 int drm_legacy_sg_alloc(struct drm_device *dev, void *data,
79 			struct drm_file *file_priv)
80 {
81 	struct drm_scatter_gather *request = data;
82 	struct drm_sg_mem *entry;
83 	unsigned long pages, i, j;
84 
85 	DRM_DEBUG("\n");
86 
87 	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
88 		return -EOPNOTSUPP;
89 
90 	if (!drm_core_check_feature(dev, DRIVER_SG))
91 		return -EOPNOTSUPP;
92 
93 	if (request->size > SIZE_MAX - PAGE_SIZE)
94 		return -EINVAL;
95 
96 	if (dev->sg)
97 		return -EINVAL;
98 
99 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
100 	if (!entry)
101 		return -ENOMEM;
102 
103 	pages = (request->size + PAGE_SIZE - 1) / PAGE_SIZE;
104 	DRM_DEBUG("size=%ld pages=%ld\n", request->size, pages);
105 
106 	entry->pages = pages;
107 	entry->pagelist = kcalloc(pages, sizeof(*entry->pagelist), GFP_KERNEL);
108 	if (!entry->pagelist) {
109 		kfree(entry);
110 		return -ENOMEM;
111 	}
112 
113 	entry->busaddr = kcalloc(pages, sizeof(*entry->busaddr), GFP_KERNEL);
114 	if (!entry->busaddr) {
115 		kfree(entry->pagelist);
116 		kfree(entry);
117 		return -ENOMEM;
118 	}
119 
120 	entry->virtual = vmalloc_32(pages << PAGE_SHIFT);
121 	if (!entry->virtual) {
122 		kfree(entry->busaddr);
123 		kfree(entry->pagelist);
124 		kfree(entry);
125 		return -ENOMEM;
126 	}
127 
128 	/* This also forces the mapping of COW pages, so our page list
129 	 * will be valid.  Please don't remove it...
130 	 */
131 	memset(entry->virtual, 0, pages << PAGE_SHIFT);
132 
133 	entry->handle = ScatterHandle((unsigned long)entry->virtual);
134 
135 	DRM_DEBUG("handle  = %08lx\n", entry->handle);
136 	DRM_DEBUG("virtual = %p\n", entry->virtual);
137 
138 	for (i = (unsigned long)entry->virtual, j = 0; j < pages;
139 	     i += PAGE_SIZE, j++) {
140 		entry->pagelist[j] = vmalloc_to_page((void *)i);
141 		if (!entry->pagelist[j])
142 			goto failed;
143 		SetPageReserved(entry->pagelist[j]);
144 	}
145 
146 	request->handle = entry->handle;
147 
148 	dev->sg = entry;
149 
150 #if DEBUG_SCATTER
151 	/* Verify that each page points to its virtual address, and vice
152 	 * versa.
153 	 */
154 	{
155 		int error = 0;
156 
157 		for (i = 0; i < pages; i++) {
158 			unsigned long *tmp;
159 
160 			tmp = page_address(entry->pagelist[i]);
161 			for (j = 0;
162 			     j < PAGE_SIZE / sizeof(unsigned long);
163 			     j++, tmp++) {
164 				*tmp = 0xcafebabe;
165 			}
166 			tmp = (unsigned long *)((u8 *) entry->virtual +
167 						(PAGE_SIZE * i));
168 			for (j = 0;
169 			     j < PAGE_SIZE / sizeof(unsigned long);
170 			     j++, tmp++) {
171 				if (*tmp != 0xcafebabe && error == 0) {
172 					error = 1;
173 					DRM_ERROR("Scatter allocation error, "
174 						  "pagelist does not match "
175 						  "virtual mapping\n");
176 				}
177 			}
178 			tmp = page_address(entry->pagelist[i]);
179 			for (j = 0;
180 			     j < PAGE_SIZE / sizeof(unsigned long);
181 			     j++, tmp++) {
182 				*tmp = 0;
183 			}
184 		}
185 		if (error == 0)
186 			DRM_ERROR("Scatter allocation matches pagelist\n");
187 	}
188 #endif
189 
190 	return 0;
191 
192       failed:
193 	drm_sg_cleanup(entry);
194 	return -ENOMEM;
195 }
196 
drm_legacy_sg_free(struct drm_device * dev,void * data,struct drm_file * file_priv)197 int drm_legacy_sg_free(struct drm_device *dev, void *data,
198 		       struct drm_file *file_priv)
199 {
200 	struct drm_scatter_gather *request = data;
201 	struct drm_sg_mem *entry;
202 
203 	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
204 		return -EOPNOTSUPP;
205 
206 	if (!drm_core_check_feature(dev, DRIVER_SG))
207 		return -EOPNOTSUPP;
208 
209 	entry = dev->sg;
210 	dev->sg = NULL;
211 
212 	if (!entry || entry->handle != request->handle)
213 		return -EINVAL;
214 
215 	DRM_DEBUG("virtual  = %p\n", entry->virtual);
216 
217 	drm_sg_cleanup(entry);
218 
219 	return 0;
220 }
221