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1/*
2 * This file is provided under the GPLv2 license.
3 *
4 * GPL LICENSE SUMMARY
5 *
6 * Copyright(c) 2014 Intel Mobile Communications GmbH
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of version 2 of the GNU General Public License as
10 * published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * The full GNU General Public License is included in this distribution
18 * in the file called COPYING.
19 *
20 * Contact Information:
21 * Intel Linux Wireless <ilw@linux.intel.com>
22 * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
23 *
24 * Author: Johannes Berg <johannes@sipsolutions.net>
25 */
26#include <linux/module.h>
27#include <linux/device.h>
28#include <linux/devcoredump.h>
29#include <linux/list.h>
30#include <linux/slab.h>
31#include <linux/fs.h>
32#include <linux/workqueue.h>
33
34static struct class devcd_class;
35
36/* global disable flag, for security purposes */
37static bool devcd_disabled;
38
39/* if data isn't read by userspace after 5 minutes then delete it */
40#define DEVCD_TIMEOUT (HZ * 60 * 5)
41
42struct devcd_entry {
43 struct device devcd_dev;
44 const void *data;
45 size_t datalen;
46 struct module *owner;
47 ssize_t (*read)(char *buffer, loff_t offset, size_t count,
48 const void *data, size_t datalen);
49 void (*free)(const void *data);
50 struct delayed_work del_wk;
51 struct device *failing_dev;
52};
53
54static struct devcd_entry *dev_to_devcd(struct device *dev)
55{
56 return container_of(dev, struct devcd_entry, devcd_dev);
57}
58
59static void devcd_dev_release(struct device *dev)
60{
61 struct devcd_entry *devcd = dev_to_devcd(dev);
62
63 devcd->free(devcd->data);
64 module_put(devcd->owner);
65
66 /*
67 * this seems racy, but I don't see a notifier or such on
68 * a struct device to know when it goes away?
69 */
70 if (devcd->failing_dev->kobj.sd)
71 sysfs_delete_link(&devcd->failing_dev->kobj, &dev->kobj,
72 "devcoredump");
73
74 put_device(devcd->failing_dev);
75 kfree(devcd);
76}
77
78static void devcd_del(struct work_struct *wk)
79{
80 struct devcd_entry *devcd;
81
82 devcd = container_of(wk, struct devcd_entry, del_wk.work);
83
84 device_del(&devcd->devcd_dev);
85 put_device(&devcd->devcd_dev);
86}
87
88static ssize_t devcd_data_read(struct file *filp, struct kobject *kobj,
89 struct bin_attribute *bin_attr,
90 char *buffer, loff_t offset, size_t count)
91{
92 struct device *dev = kobj_to_dev(kobj);
93 struct devcd_entry *devcd = dev_to_devcd(dev);
94
95 return devcd->read(buffer, offset, count, devcd->data, devcd->datalen);
96}
97
98static ssize_t devcd_data_write(struct file *filp, struct kobject *kobj,
99 struct bin_attribute *bin_attr,
100 char *buffer, loff_t offset, size_t count)
101{
102 struct device *dev = kobj_to_dev(kobj);
103 struct devcd_entry *devcd = dev_to_devcd(dev);
104
105 mod_delayed_work(system_wq, &devcd->del_wk, 0);
106
107 return count;
108}
109
110static struct bin_attribute devcd_attr_data = {
111 .attr = { .name = "data", .mode = S_IRUSR | S_IWUSR, },
112 .size = 0,
113 .read = devcd_data_read,
114 .write = devcd_data_write,
115};
116
117static struct bin_attribute *devcd_dev_bin_attrs[] = {
118 &devcd_attr_data, NULL,
119};
120
121static const struct attribute_group devcd_dev_group = {
122 .bin_attrs = devcd_dev_bin_attrs,
123};
124
125static const struct attribute_group *devcd_dev_groups[] = {
126 &devcd_dev_group, NULL,
127};
128
129static int devcd_free(struct device *dev, void *data)
130{
131 struct devcd_entry *devcd = dev_to_devcd(dev);
132
133 flush_delayed_work(&devcd->del_wk);
134 return 0;
135}
136
137static ssize_t disabled_show(struct class *class, struct class_attribute *attr,
138 char *buf)
139{
140 return sprintf(buf, "%d\n", devcd_disabled);
141}
142
143static ssize_t disabled_store(struct class *class, struct class_attribute *attr,
144 const char *buf, size_t count)
145{
146 long tmp = simple_strtol(buf, NULL, 10);
147
148 /*
149 * This essentially makes the attribute write-once, since you can't
150 * go back to not having it disabled. This is intentional, it serves
151 * as a system lockdown feature.
152 */
153 if (tmp != 1)
154 return -EINVAL;
155
156 devcd_disabled = true;
157
158 class_for_each_device(&devcd_class, NULL, NULL, devcd_free);
159
160 return count;
161}
162
163static struct class_attribute devcd_class_attrs[] = {
164 __ATTR_RW(disabled),
165 __ATTR_NULL
166};
167
168static struct class devcd_class = {
169 .name = "devcoredump",
170 .owner = THIS_MODULE,
171 .dev_release = devcd_dev_release,
172 .dev_groups = devcd_dev_groups,
173 .class_attrs = devcd_class_attrs,
174};
175
176static ssize_t devcd_readv(char *buffer, loff_t offset, size_t count,
177 const void *data, size_t datalen)
178{
179 if (offset > datalen)
180 return -EINVAL;
181
182 if (offset + count > datalen)
183 count = datalen - offset;
184
185 if (count)
186 memcpy(buffer, ((u8 *)data) + offset, count);
187
188 return count;
189}
190
191/**
192 * dev_coredumpv - create device coredump with vmalloc data
193 * @dev: the struct device for the crashed device
194 * @data: vmalloc data containing the device coredump
195 * @datalen: length of the data
196 * @gfp: allocation flags
197 *
198 * This function takes ownership of the vmalloc'ed data and will free
199 * it when it is no longer used. See dev_coredumpm() for more information.
200 */
201void dev_coredumpv(struct device *dev, const void *data, size_t datalen,
202 gfp_t gfp)
203{
204 dev_coredumpm(dev, NULL, data, datalen, gfp, devcd_readv, vfree);
205}
206EXPORT_SYMBOL_GPL(dev_coredumpv);
207
208static int devcd_match_failing(struct device *dev, const void *failing)
209{
210 struct devcd_entry *devcd = dev_to_devcd(dev);
211
212 return devcd->failing_dev == failing;
213}
214
215/**
216 * dev_coredumpm - create device coredump with read/free methods
217 * @dev: the struct device for the crashed device
218 * @owner: the module that contains the read/free functions, use %THIS_MODULE
219 * @data: data cookie for the @read/@free functions
220 * @datalen: length of the data
221 * @gfp: allocation flags
222 * @read: function to read from the given buffer
223 * @free: function to free the given buffer
224 *
225 * Creates a new device coredump for the given device. If a previous one hasn't
226 * been read yet, the new coredump is discarded. The data lifetime is determined
227 * by the device coredump framework and when it is no longer needed the @free
228 * function will be called to free the data.
229 */
230void dev_coredumpm(struct device *dev, struct module *owner,
231 const void *data, size_t datalen, gfp_t gfp,
232 ssize_t (*read)(char *buffer, loff_t offset, size_t count,
233 const void *data, size_t datalen),
234 void (*free)(const void *data))
235{
236 static atomic_t devcd_count = ATOMIC_INIT(0);
237 struct devcd_entry *devcd;
238 struct device *existing;
239
240 if (devcd_disabled)
241 goto free;
242
243 existing = class_find_device(&devcd_class, NULL, dev,
244 devcd_match_failing);
245 if (existing) {
246 put_device(existing);
247 goto free;
248 }
249
250 if (!try_module_get(owner))
251 goto free;
252
253 devcd = kzalloc(sizeof(*devcd), gfp);
254 if (!devcd)
255 goto put_module;
256
257 devcd->owner = owner;
258 devcd->data = data;
259 devcd->datalen = datalen;
260 devcd->read = read;
261 devcd->free = free;
262 devcd->failing_dev = get_device(dev);
263
264 device_initialize(&devcd->devcd_dev);
265
266 dev_set_name(&devcd->devcd_dev, "devcd%d",
267 atomic_inc_return(&devcd_count));
268 devcd->devcd_dev.class = &devcd_class;
269
270 if (device_add(&devcd->devcd_dev))
271 goto put_device;
272
273 if (sysfs_create_link(&devcd->devcd_dev.kobj, &dev->kobj,
274 "failing_device"))
275 /* nothing - symlink will be missing */;
276
277 if (sysfs_create_link(&dev->kobj, &devcd->devcd_dev.kobj,
278 "devcoredump"))
279 /* nothing - symlink will be missing */;
280
281 INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
282 schedule_delayed_work(&devcd->del_wk, DEVCD_TIMEOUT);
283
284 return;
285 put_device:
286 put_device(&devcd->devcd_dev);
287 put_module:
288 module_put(owner);
289 free:
290 free(data);
291}
292EXPORT_SYMBOL_GPL(dev_coredumpm);
293
294static int __init devcoredump_init(void)
295{
296 return class_register(&devcd_class);
297}
298__initcall(devcoredump_init);
299
300static void __exit devcoredump_exit(void)
301{
302 class_for_each_device(&devcd_class, NULL, NULL, devcd_free);
303 class_unregister(&devcd_class);
304}
305__exitcall(devcoredump_exit);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright(c) 2014 Intel Mobile Communications GmbH
4 * Copyright(c) 2015 Intel Deutschland GmbH
5 *
6 * Author: Johannes Berg <johannes@sipsolutions.net>
7 */
8#include <linux/module.h>
9#include <linux/device.h>
10#include <linux/devcoredump.h>
11#include <linux/list.h>
12#include <linux/slab.h>
13#include <linux/fs.h>
14#include <linux/workqueue.h>
15
16static struct class devcd_class;
17
18/* global disable flag, for security purposes */
19static bool devcd_disabled;
20
21/* if data isn't read by userspace after 5 minutes then delete it */
22#define DEVCD_TIMEOUT (HZ * 60 * 5)
23
24struct devcd_entry {
25 struct device devcd_dev;
26 void *data;
27 size_t datalen;
28 struct module *owner;
29 ssize_t (*read)(char *buffer, loff_t offset, size_t count,
30 void *data, size_t datalen);
31 void (*free)(void *data);
32 struct delayed_work del_wk;
33 struct device *failing_dev;
34};
35
36static struct devcd_entry *dev_to_devcd(struct device *dev)
37{
38 return container_of(dev, struct devcd_entry, devcd_dev);
39}
40
41static void devcd_dev_release(struct device *dev)
42{
43 struct devcd_entry *devcd = dev_to_devcd(dev);
44
45 devcd->free(devcd->data);
46 module_put(devcd->owner);
47
48 /*
49 * this seems racy, but I don't see a notifier or such on
50 * a struct device to know when it goes away?
51 */
52 if (devcd->failing_dev->kobj.sd)
53 sysfs_delete_link(&devcd->failing_dev->kobj, &dev->kobj,
54 "devcoredump");
55
56 put_device(devcd->failing_dev);
57 kfree(devcd);
58}
59
60static void devcd_del(struct work_struct *wk)
61{
62 struct devcd_entry *devcd;
63
64 devcd = container_of(wk, struct devcd_entry, del_wk.work);
65
66 device_del(&devcd->devcd_dev);
67 put_device(&devcd->devcd_dev);
68}
69
70static ssize_t devcd_data_read(struct file *filp, struct kobject *kobj,
71 struct bin_attribute *bin_attr,
72 char *buffer, loff_t offset, size_t count)
73{
74 struct device *dev = kobj_to_dev(kobj);
75 struct devcd_entry *devcd = dev_to_devcd(dev);
76
77 return devcd->read(buffer, offset, count, devcd->data, devcd->datalen);
78}
79
80static ssize_t devcd_data_write(struct file *filp, struct kobject *kobj,
81 struct bin_attribute *bin_attr,
82 char *buffer, loff_t offset, size_t count)
83{
84 struct device *dev = kobj_to_dev(kobj);
85 struct devcd_entry *devcd = dev_to_devcd(dev);
86
87 mod_delayed_work(system_wq, &devcd->del_wk, 0);
88
89 return count;
90}
91
92static struct bin_attribute devcd_attr_data = {
93 .attr = { .name = "data", .mode = S_IRUSR | S_IWUSR, },
94 .size = 0,
95 .read = devcd_data_read,
96 .write = devcd_data_write,
97};
98
99static struct bin_attribute *devcd_dev_bin_attrs[] = {
100 &devcd_attr_data, NULL,
101};
102
103static const struct attribute_group devcd_dev_group = {
104 .bin_attrs = devcd_dev_bin_attrs,
105};
106
107static const struct attribute_group *devcd_dev_groups[] = {
108 &devcd_dev_group, NULL,
109};
110
111static int devcd_free(struct device *dev, void *data)
112{
113 struct devcd_entry *devcd = dev_to_devcd(dev);
114
115 flush_delayed_work(&devcd->del_wk);
116 return 0;
117}
118
119static ssize_t disabled_show(struct class *class, struct class_attribute *attr,
120 char *buf)
121{
122 return sysfs_emit(buf, "%d\n", devcd_disabled);
123}
124
125static ssize_t disabled_store(struct class *class, struct class_attribute *attr,
126 const char *buf, size_t count)
127{
128 long tmp = simple_strtol(buf, NULL, 10);
129
130 /*
131 * This essentially makes the attribute write-once, since you can't
132 * go back to not having it disabled. This is intentional, it serves
133 * as a system lockdown feature.
134 */
135 if (tmp != 1)
136 return -EINVAL;
137
138 devcd_disabled = true;
139
140 class_for_each_device(&devcd_class, NULL, NULL, devcd_free);
141
142 return count;
143}
144static CLASS_ATTR_RW(disabled);
145
146static struct attribute *devcd_class_attrs[] = {
147 &class_attr_disabled.attr,
148 NULL,
149};
150ATTRIBUTE_GROUPS(devcd_class);
151
152static struct class devcd_class = {
153 .name = "devcoredump",
154 .owner = THIS_MODULE,
155 .dev_release = devcd_dev_release,
156 .dev_groups = devcd_dev_groups,
157 .class_groups = devcd_class_groups,
158};
159
160static ssize_t devcd_readv(char *buffer, loff_t offset, size_t count,
161 void *data, size_t datalen)
162{
163 return memory_read_from_buffer(buffer, count, &offset, data, datalen);
164}
165
166static void devcd_freev(void *data)
167{
168 vfree(data);
169}
170
171/**
172 * dev_coredumpv - create device coredump with vmalloc data
173 * @dev: the struct device for the crashed device
174 * @data: vmalloc data containing the device coredump
175 * @datalen: length of the data
176 * @gfp: allocation flags
177 *
178 * This function takes ownership of the vmalloc'ed data and will free
179 * it when it is no longer used. See dev_coredumpm() for more information.
180 */
181void dev_coredumpv(struct device *dev, void *data, size_t datalen,
182 gfp_t gfp)
183{
184 dev_coredumpm(dev, NULL, data, datalen, gfp, devcd_readv, devcd_freev);
185}
186EXPORT_SYMBOL_GPL(dev_coredumpv);
187
188static int devcd_match_failing(struct device *dev, const void *failing)
189{
190 struct devcd_entry *devcd = dev_to_devcd(dev);
191
192 return devcd->failing_dev == failing;
193}
194
195/**
196 * devcd_free_sgtable - free all the memory of the given scatterlist table
197 * (i.e. both pages and scatterlist instances)
198 * NOTE: if two tables allocated with devcd_alloc_sgtable and then chained
199 * using the sg_chain function then that function should be called only once
200 * on the chained table
201 * @data: pointer to sg_table to free
202 */
203static void devcd_free_sgtable(void *data)
204{
205 _devcd_free_sgtable(data);
206}
207
208/**
209 * devcd_read_from_sgtable - copy data from sg_table to a given buffer
210 * and return the number of bytes read
211 * @buffer: the buffer to copy the data to it
212 * @buf_len: the length of the buffer
213 * @data: the scatterlist table to copy from
214 * @offset: start copy from @offset@ bytes from the head of the data
215 * in the given scatterlist
216 * @data_len: the length of the data in the sg_table
217 */
218static ssize_t devcd_read_from_sgtable(char *buffer, loff_t offset,
219 size_t buf_len, void *data,
220 size_t data_len)
221{
222 struct scatterlist *table = data;
223
224 if (offset > data_len)
225 return -EINVAL;
226
227 if (offset + buf_len > data_len)
228 buf_len = data_len - offset;
229 return sg_pcopy_to_buffer(table, sg_nents(table), buffer, buf_len,
230 offset);
231}
232
233/**
234 * dev_coredumpm - create device coredump with read/free methods
235 * @dev: the struct device for the crashed device
236 * @owner: the module that contains the read/free functions, use %THIS_MODULE
237 * @data: data cookie for the @read/@free functions
238 * @datalen: length of the data
239 * @gfp: allocation flags
240 * @read: function to read from the given buffer
241 * @free: function to free the given buffer
242 *
243 * Creates a new device coredump for the given device. If a previous one hasn't
244 * been read yet, the new coredump is discarded. The data lifetime is determined
245 * by the device coredump framework and when it is no longer needed the @free
246 * function will be called to free the data.
247 */
248void dev_coredumpm(struct device *dev, struct module *owner,
249 void *data, size_t datalen, gfp_t gfp,
250 ssize_t (*read)(char *buffer, loff_t offset, size_t count,
251 void *data, size_t datalen),
252 void (*free)(void *data))
253{
254 static atomic_t devcd_count = ATOMIC_INIT(0);
255 struct devcd_entry *devcd;
256 struct device *existing;
257
258 if (devcd_disabled)
259 goto free;
260
261 existing = class_find_device(&devcd_class, NULL, dev,
262 devcd_match_failing);
263 if (existing) {
264 put_device(existing);
265 goto free;
266 }
267
268 if (!try_module_get(owner))
269 goto free;
270
271 devcd = kzalloc(sizeof(*devcd), gfp);
272 if (!devcd)
273 goto put_module;
274
275 devcd->owner = owner;
276 devcd->data = data;
277 devcd->datalen = datalen;
278 devcd->read = read;
279 devcd->free = free;
280 devcd->failing_dev = get_device(dev);
281
282 device_initialize(&devcd->devcd_dev);
283
284 dev_set_name(&devcd->devcd_dev, "devcd%d",
285 atomic_inc_return(&devcd_count));
286 devcd->devcd_dev.class = &devcd_class;
287
288 if (device_add(&devcd->devcd_dev))
289 goto put_device;
290
291 /*
292 * These should normally not fail, but there is no problem
293 * continuing without the links, so just warn instead of
294 * failing.
295 */
296 if (sysfs_create_link(&devcd->devcd_dev.kobj, &dev->kobj,
297 "failing_device") ||
298 sysfs_create_link(&dev->kobj, &devcd->devcd_dev.kobj,
299 "devcoredump"))
300 dev_warn(dev, "devcoredump create_link failed\n");
301
302 INIT_DELAYED_WORK(&devcd->del_wk, devcd_del);
303 schedule_delayed_work(&devcd->del_wk, DEVCD_TIMEOUT);
304
305 return;
306 put_device:
307 put_device(&devcd->devcd_dev);
308 put_module:
309 module_put(owner);
310 free:
311 free(data);
312}
313EXPORT_SYMBOL_GPL(dev_coredumpm);
314
315/**
316 * dev_coredumpsg - create device coredump that uses scatterlist as data
317 * parameter
318 * @dev: the struct device for the crashed device
319 * @table: the dump data
320 * @datalen: length of the data
321 * @gfp: allocation flags
322 *
323 * Creates a new device coredump for the given device. If a previous one hasn't
324 * been read yet, the new coredump is discarded. The data lifetime is determined
325 * by the device coredump framework and when it is no longer needed
326 * it will free the data.
327 */
328void dev_coredumpsg(struct device *dev, struct scatterlist *table,
329 size_t datalen, gfp_t gfp)
330{
331 dev_coredumpm(dev, NULL, table, datalen, gfp, devcd_read_from_sgtable,
332 devcd_free_sgtable);
333}
334EXPORT_SYMBOL_GPL(dev_coredumpsg);
335
336static int __init devcoredump_init(void)
337{
338 return class_register(&devcd_class);
339}
340__initcall(devcoredump_init);
341
342static void __exit devcoredump_exit(void)
343{
344 class_for_each_device(&devcd_class, NULL, NULL, devcd_free);
345 class_unregister(&devcd_class);
346}
347__exitcall(devcoredump_exit);