Commit | Line | Data |
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ca01d6dd TL |
1 | /* |
2 | * Persistent Storage - platform driver interface parts. | |
3 | * | |
f29e5956 | 4 | * Copyright (C) 2007-2008 Google, Inc. |
ca01d6dd TL |
5 | * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com> |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
19 | */ | |
20 | ||
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> | |
f29e5956 | 26 | #include <linux/console.h> |
ca01d6dd TL |
27 | #include <linux/module.h> |
28 | #include <linux/pstore.h> | |
29 | #include <linux/string.h> | |
6dda9266 | 30 | #include <linux/timer.h> |
ca01d6dd TL |
31 | #include <linux/slab.h> |
32 | #include <linux/uaccess.h> | |
abd4d558 | 33 | #include <linux/hardirq.h> |
a3f5f075 | 34 | #include <linux/jiffies.h> |
6dda9266 | 35 | #include <linux/workqueue.h> |
ca01d6dd TL |
36 | |
37 | #include "internal.h" | |
38 | ||
6dda9266 LT |
39 | /* |
40 | * We defer making "oops" entries appear in pstore - see | |
41 | * whether the system is actually still running well enough | |
42 | * to let someone see the entry | |
43 | */ | |
521f7288 | 44 | static int pstore_update_ms = -1; |
a3f5f075 AV |
45 | module_param_named(update_ms, pstore_update_ms, int, 0600); |
46 | MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content " | |
521f7288 AV |
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)"); | |
6dda9266 LT |
50 | |
51 | static int pstore_new_entry; | |
52 | ||
53 | static void pstore_timefunc(unsigned long); | |
54 | static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0); | |
55 | ||
56 | static void pstore_dowork(struct work_struct *); | |
57 | static DECLARE_WORK(pstore_work, pstore_dowork); | |
58 | ||
ca01d6dd TL |
59 | /* |
60 | * pstore_lock just protects "psinfo" during | |
61 | * calls to pstore_register() | |
62 | */ | |
63 | static DEFINE_SPINLOCK(pstore_lock); | |
060287b8 | 64 | struct pstore_info *psinfo; |
ca01d6dd | 65 | |
dee28e72 MG |
66 | static char *backend; |
67 | ||
366f7e7a | 68 | /* How much of the console log to snapshot */ |
ca01d6dd TL |
69 | static unsigned long kmsg_bytes = 10240; |
70 | ||
366f7e7a | 71 | void pstore_set_kmsg_bytes(int bytes) |
ca01d6dd | 72 | { |
366f7e7a | 73 | kmsg_bytes = bytes; |
ca01d6dd TL |
74 | } |
75 | ||
ca01d6dd TL |
76 | /* Tag each group of saved records with a sequence number */ |
77 | static int oopscount; | |
78 | ||
381b872c SA |
79 | static 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 | } | |
9f6af27f | 98 | |
9f244e9c SA |
99 | bool pstore_cannot_block_path(enum kmsg_dump_reason reason) |
100 | { | |
101 | /* | |
102 | * In case of NMI path, pstore shouldn't be blocked | |
103 | * regardless of reason. | |
104 | */ | |
105 | if (in_nmi()) | |
106 | return true; | |
107 | ||
108 | switch (reason) { | |
109 | /* In panic case, other cpus are stopped by smp_send_stop(). */ | |
110 | case KMSG_DUMP_PANIC: | |
111 | /* Emergency restart shouldn't be blocked by spin lock. */ | |
112 | case KMSG_DUMP_EMERG: | |
113 | return true; | |
114 | default: | |
115 | return false; | |
116 | } | |
117 | } | |
118 | EXPORT_SYMBOL_GPL(pstore_cannot_block_path); | |
119 | ||
ca01d6dd TL |
120 | /* |
121 | * callback from kmsg_dump. (s2,l2) has the most recently | |
122 | * written bytes, older bytes are in (s1,l1). Save as much | |
123 | * as we can from the end of the buffer. | |
124 | */ | |
125 | static void pstore_dump(struct kmsg_dumper *dumper, | |
e2ae715d | 126 | enum kmsg_dump_reason reason) |
ca01d6dd | 127 | { |
e2ae715d | 128 | unsigned long total = 0; |
381b872c | 129 | const char *why; |
ca01d6dd | 130 | u64 id; |
b94fdd07 | 131 | unsigned int part = 1; |
abd4d558 DZ |
132 | unsigned long flags = 0; |
133 | int is_locked = 0; | |
e2ae715d | 134 | int ret; |
ca01d6dd | 135 | |
381b872c | 136 | why = get_reason_str(reason); |
9f6af27f | 137 | |
9f244e9c SA |
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 | } | |
abd4d558 DZ |
144 | } else |
145 | spin_lock_irqsave(&psinfo->buf_lock, flags); | |
ca01d6dd TL |
146 | oopscount++; |
147 | while (total < kmsg_bytes) { | |
e2ae715d KS |
148 | char *dst; |
149 | unsigned long size; | |
150 | int hsize; | |
151 | size_t len; | |
152 | ||
ca01d6dd | 153 | dst = psinfo->buf; |
56280682 | 154 | hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part); |
ca01d6dd TL |
155 | size = psinfo->bufsize - hsize; |
156 | dst += hsize; | |
157 | ||
e2ae715d | 158 | if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len)) |
ca01d6dd TL |
159 | break; |
160 | ||
3d6d8d20 | 161 | ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part, |
6bbbca73 | 162 | oopscount, hsize, hsize + len, psinfo); |
b238b8fa | 163 | if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted()) |
6dda9266 | 164 | pstore_new_entry = 1; |
e2ae715d KS |
165 | |
166 | total += hsize + len; | |
56280682 | 167 | part++; |
ca01d6dd | 168 | } |
9f244e9c | 169 | if (pstore_cannot_block_path(reason)) { |
abd4d558 | 170 | if (is_locked) |
9f244e9c | 171 | spin_unlock_irqrestore(&psinfo->buf_lock, flags); |
abd4d558 DZ |
172 | } else |
173 | spin_unlock_irqrestore(&psinfo->buf_lock, flags); | |
ca01d6dd TL |
174 | } |
175 | ||
176 | static struct kmsg_dumper pstore_dumper = { | |
177 | .dump = pstore_dump, | |
178 | }; | |
179 | ||
f29e5956 AV |
180 | #ifdef CONFIG_PSTORE_CONSOLE |
181 | static 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; | |
70a6f46d | 187 | u64 id; |
f29e5956 AV |
188 | |
189 | if (c > psinfo->bufsize) | |
190 | c = psinfo->bufsize; | |
80c9d03c CL |
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 | } | |
f29e5956 | 198 | memcpy(psinfo->buf, s, c); |
6bbbca73 | 199 | psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo); |
f29e5956 AV |
200 | spin_unlock_irqrestore(&psinfo->buf_lock, flags); |
201 | s += c; | |
202 | c = e - s; | |
203 | } | |
204 | } | |
205 | ||
206 | static 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 | ||
213 | static void pstore_register_console(void) | |
214 | { | |
215 | register_console(&pstore_console); | |
216 | } | |
217 | #else | |
218 | static void pstore_register_console(void) {} | |
219 | #endif | |
220 | ||
897dba02 AV |
221 | static int pstore_write_compat(enum pstore_type_id type, |
222 | enum kmsg_dump_reason reason, | |
755d4fe4 | 223 | u64 *id, unsigned int part, int count, |
6bbbca73 AB |
224 | size_t hsize, size_t size, |
225 | struct pstore_info *psi) | |
897dba02 | 226 | { |
6bbbca73 AB |
227 | return psi->write_buf(type, reason, id, part, psinfo->buf, hsize, |
228 | size, psi); | |
897dba02 AV |
229 | } |
230 | ||
ca01d6dd TL |
231 | /* |
232 | * platform specific persistent storage driver registers with | |
233 | * us here. If pstore is already mounted, call the platform | |
234 | * read function right away to populate the file system. If not | |
235 | * then the pstore mount code will call us later to fill out | |
236 | * the file system. | |
237 | * | |
238 | * Register with kmsg_dump to save last part of console log on panic. | |
239 | */ | |
240 | int pstore_register(struct pstore_info *psi) | |
241 | { | |
242 | struct module *owner = psi->owner; | |
243 | ||
8e48b1a8 LS |
244 | if (backend && strcmp(backend, psi->name)) |
245 | return -EPERM; | |
246 | ||
ca01d6dd TL |
247 | spin_lock(&pstore_lock); |
248 | if (psinfo) { | |
249 | spin_unlock(&pstore_lock); | |
250 | return -EBUSY; | |
251 | } | |
dee28e72 | 252 | |
897dba02 AV |
253 | if (!psi->write) |
254 | psi->write = pstore_write_compat; | |
ca01d6dd | 255 | psinfo = psi; |
f6f82851 | 256 | mutex_init(&psinfo->read_mutex); |
ca01d6dd TL |
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()) | |
6dda9266 | 265 | pstore_get_records(0); |
ca01d6dd TL |
266 | |
267 | kmsg_dump_register(&pstore_dumper); | |
f29e5956 | 268 | pstore_register_console(); |
65f8c95e | 269 | pstore_register_ftrace(); |
ca01d6dd | 270 | |
a3f5f075 AV |
271 | if (pstore_update_ms >= 0) { |
272 | pstore_timer.expires = jiffies + | |
273 | msecs_to_jiffies(pstore_update_ms); | |
274 | add_timer(&pstore_timer); | |
275 | } | |
6dda9266 | 276 | |
8e48b1a8 LS |
277 | pr_info("pstore: Registered %s as persistent store backend\n", |
278 | psi->name); | |
279 | ||
ca01d6dd TL |
280 | return 0; |
281 | } | |
282 | EXPORT_SYMBOL_GPL(pstore_register); | |
283 | ||
284 | /* | |
6dda9266 LT |
285 | * Read all the records from the persistent store. Create |
286 | * files in our filesystem. Don't warn about -EEXIST errors | |
287 | * when we are re-scanning the backing store looking to add new | |
288 | * error records. | |
ca01d6dd | 289 | */ |
6dda9266 | 290 | void pstore_get_records(int quiet) |
ca01d6dd TL |
291 | { |
292 | struct pstore_info *psi = psinfo; | |
f6f82851 | 293 | char *buf = NULL; |
8d38d74b | 294 | ssize_t size; |
ca01d6dd | 295 | u64 id; |
755d4fe4 | 296 | int count; |
ca01d6dd TL |
297 | enum pstore_type_id type; |
298 | struct timespec time; | |
06cf91b4 | 299 | int failed = 0, rc; |
ca01d6dd TL |
300 | |
301 | if (!psi) | |
302 | return; | |
303 | ||
f6f82851 | 304 | mutex_lock(&psi->read_mutex); |
2174f6df | 305 | if (psi->open && psi->open(psi)) |
06cf91b4 CG |
306 | goto out; |
307 | ||
755d4fe4 SA |
308 | while ((size = psi->read(&id, &type, &count, &time, &buf, psi)) > 0) { |
309 | rc = pstore_mkfile(type, psi->name, id, count, buf, | |
310 | (size_t)size, time, psi); | |
f6f82851 KC |
311 | kfree(buf); |
312 | buf = NULL; | |
6dda9266 | 313 | if (rc && (rc != -EEXIST || !quiet)) |
ca01d6dd TL |
314 | failed++; |
315 | } | |
2174f6df KC |
316 | if (psi->close) |
317 | psi->close(psi); | |
06cf91b4 | 318 | out: |
f6f82851 | 319 | mutex_unlock(&psi->read_mutex); |
ca01d6dd TL |
320 | |
321 | if (failed) | |
322 | printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n", | |
323 | failed, psi->name); | |
324 | } | |
325 | ||
6dda9266 LT |
326 | static void pstore_dowork(struct work_struct *work) |
327 | { | |
328 | pstore_get_records(1); | |
329 | } | |
330 | ||
331 | static void pstore_timefunc(unsigned long dummy) | |
332 | { | |
333 | if (pstore_new_entry) { | |
334 | pstore_new_entry = 0; | |
335 | schedule_work(&pstore_work); | |
336 | } | |
337 | ||
a3f5f075 | 338 | mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms)); |
6dda9266 LT |
339 | } |
340 | ||
dee28e72 MG |
341 | module_param(backend, charp, 0444); |
342 | MODULE_PARM_DESC(backend, "Pstore backend to use"); |