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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
19static bool devcd_disabled;
20
21
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);
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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);
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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}
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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}
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203static void devcd_free_sgtable(void *data)
204{
205 _devcd_free_sgtable(data);
206}
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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}
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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;
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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);
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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);
348