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21#include <linux/atomic.h>
22#include <linux/types.h>
23#include <linux/errno.h>
24#include <linux/init.h>
25#include <linux/kmsg_dump.h>
26#include <linux/console.h>
27#include <linux/module.h>
28#include <linux/pstore.h>
29#include <linux/string.h>
30#include <linux/timer.h>
31#include <linux/slab.h>
32#include <linux/uaccess.h>
33#include <linux/hardirq.h>
34#include <linux/jiffies.h>
35#include <linux/workqueue.h>
36
37#include "internal.h"
38
39
40
41
42
43
44static int pstore_update_ms = -1;
45module_param_named(update_ms, pstore_update_ms, int, 0600);
46MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
47 "(default is -1, which means runtime updates are disabled; "
48 "enabling this option is not safe, it may lead to further "
49 "corruption on Oopses)");
50
51static int pstore_new_entry;
52
53static void pstore_timefunc(unsigned long);
54static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
55
56static void pstore_dowork(struct work_struct *);
57static DECLARE_WORK(pstore_work, pstore_dowork);
58
59
60
61
62
63static DEFINE_SPINLOCK(pstore_lock);
64struct pstore_info *psinfo;
65
66static char *backend;
67
68
69static unsigned long kmsg_bytes = 10240;
70
71void pstore_set_kmsg_bytes(int bytes)
72{
73 kmsg_bytes = bytes;
74}
75
76
77static int oopscount;
78
79static const char *get_reason_str(enum kmsg_dump_reason reason)
80{
81 switch (reason) {
82 case KMSG_DUMP_PANIC:
83 return "Panic";
84 case KMSG_DUMP_OOPS:
85 return "Oops";
86 case KMSG_DUMP_EMERG:
87 return "Emergency";
88 case KMSG_DUMP_RESTART:
89 return "Restart";
90 case KMSG_DUMP_HALT:
91 return "Halt";
92 case KMSG_DUMP_POWEROFF:
93 return "Poweroff";
94 default:
95 return "Unknown";
96 }
97}
98
99bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
100{
101
102
103
104
105 if (in_nmi())
106 return true;
107
108 switch (reason) {
109
110 case KMSG_DUMP_PANIC:
111
112 case KMSG_DUMP_EMERG:
113 return true;
114 default:
115 return false;
116 }
117}
118EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
119
120
121
122
123
124
125static void pstore_dump(struct kmsg_dumper *dumper,
126 enum kmsg_dump_reason reason)
127{
128 unsigned long total = 0;
129 const char *why;
130 u64 id;
131 unsigned int part = 1;
132 unsigned long flags = 0;
133 int is_locked = 0;
134 int ret;
135
136 why = get_reason_str(reason);
137
138 if (pstore_cannot_block_path(reason)) {
139 is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
140 if (!is_locked) {
141 pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
142 , in_nmi() ? "NMI" : why);
143 }
144 } else
145 spin_lock_irqsave(&psinfo->buf_lock, flags);
146 oopscount++;
147 while (total < kmsg_bytes) {
148 char *dst;
149 unsigned long size;
150 int hsize;
151 size_t len;
152
153 dst = psinfo->buf;
154 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
155 size = psinfo->bufsize - hsize;
156 dst += hsize;
157
158 if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
159 break;
160
161 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
162 oopscount, hsize + len, psinfo);
163 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
164 pstore_new_entry = 1;
165
166 total += hsize + len;
167 part++;
168 }
169 if (pstore_cannot_block_path(reason)) {
170 if (is_locked)
171 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
172 } else
173 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
174}
175
176static struct kmsg_dumper pstore_dumper = {
177 .dump = pstore_dump,
178};
179
180#ifdef CONFIG_PSTORE_CONSOLE
181static void pstore_console_write(struct console *con, const char *s, unsigned c)
182{
183 const char *e = s + c;
184
185 while (s < e) {
186 unsigned long flags;
187 u64 id;
188
189 if (c > psinfo->bufsize)
190 c = psinfo->bufsize;
191
192 if (oops_in_progress) {
193 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
194 break;
195 } else {
196 spin_lock_irqsave(&psinfo->buf_lock, flags);
197 }
198 memcpy(psinfo->buf, s, c);
199 psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, c, psinfo);
200 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
201 s += c;
202 c = e - s;
203 }
204}
205
206static struct console pstore_console = {
207 .name = "pstore",
208 .write = pstore_console_write,
209 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
210 .index = -1,
211};
212
213static void pstore_register_console(void)
214{
215 register_console(&pstore_console);
216}
217#else
218static void pstore_register_console(void) {}
219#endif
220
221static int pstore_write_compat(enum pstore_type_id type,
222 enum kmsg_dump_reason reason,
223 u64 *id, unsigned int part, int count,
224 size_t size, struct pstore_info *psi)
225{
226 return psi->write_buf(type, reason, id, part, psinfo->buf, size, psi);
227}
228
229
230
231
232
233
234
235
236
237
238int pstore_register(struct pstore_info *psi)
239{
240 struct module *owner = psi->owner;
241
242 spin_lock(&pstore_lock);
243 if (psinfo) {
244 spin_unlock(&pstore_lock);
245 return -EBUSY;
246 }
247
248 if (backend && strcmp(backend, psi->name)) {
249 spin_unlock(&pstore_lock);
250 return -EINVAL;
251 }
252
253 if (!psi->write)
254 psi->write = pstore_write_compat;
255 psinfo = psi;
256 mutex_init(&psinfo->read_mutex);
257 spin_unlock(&pstore_lock);
258
259 if (owner && !try_module_get(owner)) {
260 psinfo = NULL;
261 return -EINVAL;
262 }
263
264 if (pstore_is_mounted())
265 pstore_get_records(0);
266
267 kmsg_dump_register(&pstore_dumper);
268 pstore_register_console();
269 pstore_register_ftrace();
270
271 if (pstore_update_ms >= 0) {
272 pstore_timer.expires = jiffies +
273 msecs_to_jiffies(pstore_update_ms);
274 add_timer(&pstore_timer);
275 }
276
277 return 0;
278}
279EXPORT_SYMBOL_GPL(pstore_register);
280
281
282
283
284
285
286
287void pstore_get_records(int quiet)
288{
289 struct pstore_info *psi = psinfo;
290 char *buf = NULL;
291 ssize_t size;
292 u64 id;
293 int count;
294 enum pstore_type_id type;
295 struct timespec time;
296 int failed = 0, rc;
297
298 if (!psi)
299 return;
300
301 mutex_lock(&psi->read_mutex);
302 if (psi->open && psi->open(psi))
303 goto out;
304
305 while ((size = psi->read(&id, &type, &count, &time, &buf, psi)) > 0) {
306 rc = pstore_mkfile(type, psi->name, id, count, buf,
307 (size_t)size, time, psi);
308 kfree(buf);
309 buf = NULL;
310 if (rc && (rc != -EEXIST || !quiet))
311 failed++;
312 }
313 if (psi->close)
314 psi->close(psi);
315out:
316 mutex_unlock(&psi->read_mutex);
317
318 if (failed)
319 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
320 failed, psi->name);
321}
322
323static void pstore_dowork(struct work_struct *work)
324{
325 pstore_get_records(1);
326}
327
328static void pstore_timefunc(unsigned long dummy)
329{
330 if (pstore_new_entry) {
331 pstore_new_entry = 0;
332 schedule_work(&pstore_work);
333 }
334
335 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
336}
337
338module_param(backend, charp, 0444);
339MODULE_PARM_DESC(backend, "Pstore backend to use");
340