blob: 29996e8793a7753139bdb7105bc00994bb411ba0 [file] [log] [blame]
Tony Luckca01d6d2010-12-28 14:25:21 -08001/*
2 * Persistent Storage - platform driver interface parts.
3 *
Anton Vorontsovf29e5952012-05-26 06:20:19 -07004 * Copyright (C) 2007-2008 Google, Inc.
Tony Luckca01d6d2010-12-28 14:25:21 -08005 * 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>
Anton Vorontsovf29e5952012-05-26 06:20:19 -070026#include <linux/console.h>
Tony Luckca01d6d2010-12-28 14:25:21 -080027#include <linux/module.h>
28#include <linux/pstore.h>
29#include <linux/string.h>
Luck, Tony6dda9262011-08-11 15:14:39 -070030#include <linux/timer.h>
Tony Luckca01d6d2010-12-28 14:25:21 -080031#include <linux/slab.h>
32#include <linux/uaccess.h>
Don Zickusabd4d552011-08-12 10:54:51 -070033#include <linux/hardirq.h>
Anton Vorontsova3f5f072012-05-26 06:20:28 -070034#include <linux/jiffies.h>
Luck, Tony6dda9262011-08-11 15:14:39 -070035#include <linux/workqueue.h>
Tony Luckca01d6d2010-12-28 14:25:21 -080036
37#include "internal.h"
38
39/*
Luck, Tony6dda9262011-08-11 15:14:39 -070040 * 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 */
Anton Vorontsov521f72882012-05-26 06:20:29 -070044static int pstore_update_ms = -1;
Anton Vorontsova3f5f072012-05-26 06:20:28 -070045module_param_named(update_ms, pstore_update_ms, int, 0600);
46MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
Anton Vorontsov521f72882012-05-26 06:20:29 -070047 "(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)");
Luck, Tony6dda9262011-08-11 15:14:39 -070050
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/*
Tony Luckca01d6d2010-12-28 14:25:21 -080060 * pstore_lock just protects "psinfo" during
61 * calls to pstore_register()
62 */
63static DEFINE_SPINLOCK(pstore_lock);
Anton Vorontsov060287b2012-07-09 17:10:41 -070064struct pstore_info *psinfo;
Tony Luckca01d6d2010-12-28 14:25:21 -080065
Matthew Garrettdee28e72011-07-21 16:57:55 -040066static char *backend;
67
Luck, Tony366f7e72011-03-18 15:33:43 -070068/* How much of the console log to snapshot */
Tony Luckca01d6d2010-12-28 14:25:21 -080069static unsigned long kmsg_bytes = 10240;
70
Luck, Tony366f7e72011-03-18 15:33:43 -070071void pstore_set_kmsg_bytes(int bytes)
Tony Luckca01d6d2010-12-28 14:25:21 -080072{
Luck, Tony366f7e72011-03-18 15:33:43 -070073 kmsg_bytes = bytes;
Tony Luckca01d6d2010-12-28 14:25:21 -080074}
75
Tony Luckca01d6d2010-12-28 14:25:21 -080076/* Tag each group of saved records with a sequence number */
77static int oopscount;
78
Seiji Aguchi381b8722012-03-16 15:36:59 -070079static 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}
Tony Luck9f6af272011-03-22 16:01:49 -070098
Tony Luckca01d6d2010-12-28 14:25:21 -080099/*
100 * callback from kmsg_dump. (s2,l2) has the most recently
101 * written bytes, older bytes are in (s1,l1). Save as much
102 * as we can from the end of the buffer.
103 */
104static void pstore_dump(struct kmsg_dumper *dumper,
Kay Sieverse2ae7152012-06-15 14:07:51 +0200105 enum kmsg_dump_reason reason)
Tony Luckca01d6d2010-12-28 14:25:21 -0800106{
Kay Sieverse2ae7152012-06-15 14:07:51 +0200107 unsigned long total = 0;
Seiji Aguchi381b8722012-03-16 15:36:59 -0700108 const char *why;
Tony Luckca01d6d2010-12-28 14:25:21 -0800109 u64 id;
Matthew Garrettb94fdd02011-07-21 16:57:54 -0400110 unsigned int part = 1;
Don Zickusabd4d552011-08-12 10:54:51 -0700111 unsigned long flags = 0;
112 int is_locked = 0;
Kay Sieverse2ae7152012-06-15 14:07:51 +0200113 int ret;
Tony Luckca01d6d2010-12-28 14:25:21 -0800114
Seiji Aguchi381b8722012-03-16 15:36:59 -0700115 why = get_reason_str(reason);
Tony Luck9f6af272011-03-22 16:01:49 -0700116
Don Zickusabd4d552011-08-12 10:54:51 -0700117 if (in_nmi()) {
118 is_locked = spin_trylock(&psinfo->buf_lock);
119 if (!is_locked)
120 pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
121 } else
122 spin_lock_irqsave(&psinfo->buf_lock, flags);
Tony Luckca01d6d2010-12-28 14:25:21 -0800123 oopscount++;
124 while (total < kmsg_bytes) {
Kay Sieverse2ae7152012-06-15 14:07:51 +0200125 char *dst;
126 unsigned long size;
127 int hsize;
128 size_t len;
129
Tony Luckca01d6d2010-12-28 14:25:21 -0800130 dst = psinfo->buf;
Matthew Garrett56280682011-07-21 16:57:53 -0400131 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
Tony Luckca01d6d2010-12-28 14:25:21 -0800132 size = psinfo->bufsize - hsize;
133 dst += hsize;
134
Kay Sieverse2ae7152012-06-15 14:07:51 +0200135 if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
Tony Luckca01d6d2010-12-28 14:25:21 -0800136 break;
137
Kees Cook3d6d8d22011-11-17 13:13:29 -0800138 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
Kay Sieverse2ae7152012-06-15 14:07:51 +0200139 hsize + len, psinfo);
Chen Gongb238b8f2011-10-12 09:17:24 -0700140 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
Luck, Tony6dda9262011-08-11 15:14:39 -0700141 pstore_new_entry = 1;
Kay Sieverse2ae7152012-06-15 14:07:51 +0200142
143 total += hsize + len;
Matthew Garrett56280682011-07-21 16:57:53 -0400144 part++;
Tony Luckca01d6d2010-12-28 14:25:21 -0800145 }
Don Zickusabd4d552011-08-12 10:54:51 -0700146 if (in_nmi()) {
147 if (is_locked)
148 spin_unlock(&psinfo->buf_lock);
149 } else
150 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
Tony Luckca01d6d2010-12-28 14:25:21 -0800151}
152
153static struct kmsg_dumper pstore_dumper = {
154 .dump = pstore_dump,
155};
156
Anton Vorontsovf29e5952012-05-26 06:20:19 -0700157#ifdef CONFIG_PSTORE_CONSOLE
158static void pstore_console_write(struct console *con, const char *s, unsigned c)
159{
160 const char *e = s + c;
161
162 while (s < e) {
163 unsigned long flags;
164
165 if (c > psinfo->bufsize)
166 c = psinfo->bufsize;
167 spin_lock_irqsave(&psinfo->buf_lock, flags);
168 memcpy(psinfo->buf, s, c);
169 psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
170 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
171 s += c;
172 c = e - s;
173 }
174}
175
176static struct console pstore_console = {
177 .name = "pstore",
178 .write = pstore_console_write,
179 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
180 .index = -1,
181};
182
183static void pstore_register_console(void)
184{
185 register_console(&pstore_console);
186}
187#else
188static void pstore_register_console(void) {}
189#endif
190
Anton Vorontsov897dba02012-07-09 17:10:40 -0700191static int pstore_write_compat(enum pstore_type_id type,
192 enum kmsg_dump_reason reason,
193 u64 *id, unsigned int part,
194 size_t size, struct pstore_info *psi)
195{
196 return psi->write_buf(type, reason, id, part, psinfo->buf, size, psi);
197}
198
Tony Luckca01d6d2010-12-28 14:25:21 -0800199/*
200 * platform specific persistent storage driver registers with
201 * us here. If pstore is already mounted, call the platform
202 * read function right away to populate the file system. If not
203 * then the pstore mount code will call us later to fill out
204 * the file system.
205 *
206 * Register with kmsg_dump to save last part of console log on panic.
207 */
208int pstore_register(struct pstore_info *psi)
209{
210 struct module *owner = psi->owner;
211
212 spin_lock(&pstore_lock);
213 if (psinfo) {
214 spin_unlock(&pstore_lock);
215 return -EBUSY;
216 }
Matthew Garrettdee28e72011-07-21 16:57:55 -0400217
218 if (backend && strcmp(backend, psi->name)) {
219 spin_unlock(&pstore_lock);
220 return -EINVAL;
221 }
222
Anton Vorontsov897dba02012-07-09 17:10:40 -0700223 if (!psi->write)
224 psi->write = pstore_write_compat;
Tony Luckca01d6d2010-12-28 14:25:21 -0800225 psinfo = psi;
Kees Cookf6f82852011-11-17 12:58:07 -0800226 mutex_init(&psinfo->read_mutex);
Tony Luckca01d6d2010-12-28 14:25:21 -0800227 spin_unlock(&pstore_lock);
228
229 if (owner && !try_module_get(owner)) {
230 psinfo = NULL;
231 return -EINVAL;
232 }
233
234 if (pstore_is_mounted())
Luck, Tony6dda9262011-08-11 15:14:39 -0700235 pstore_get_records(0);
Tony Luckca01d6d2010-12-28 14:25:21 -0800236
237 kmsg_dump_register(&pstore_dumper);
Anton Vorontsovf29e5952012-05-26 06:20:19 -0700238 pstore_register_console();
Tony Luckca01d6d2010-12-28 14:25:21 -0800239
Anton Vorontsova3f5f072012-05-26 06:20:28 -0700240 if (pstore_update_ms >= 0) {
241 pstore_timer.expires = jiffies +
242 msecs_to_jiffies(pstore_update_ms);
243 add_timer(&pstore_timer);
244 }
Luck, Tony6dda9262011-08-11 15:14:39 -0700245
Tony Luckca01d6d2010-12-28 14:25:21 -0800246 return 0;
247}
248EXPORT_SYMBOL_GPL(pstore_register);
249
250/*
Luck, Tony6dda9262011-08-11 15:14:39 -0700251 * Read all the records from the persistent store. Create
252 * files in our filesystem. Don't warn about -EEXIST errors
253 * when we are re-scanning the backing store looking to add new
254 * error records.
Tony Luckca01d6d2010-12-28 14:25:21 -0800255 */
Luck, Tony6dda9262011-08-11 15:14:39 -0700256void pstore_get_records(int quiet)
Tony Luckca01d6d2010-12-28 14:25:21 -0800257{
258 struct pstore_info *psi = psinfo;
Kees Cookf6f82852011-11-17 12:58:07 -0800259 char *buf = NULL;
Chen Gong8d38d742011-05-16 10:58:57 -0700260 ssize_t size;
Tony Luckca01d6d2010-12-28 14:25:21 -0800261 u64 id;
262 enum pstore_type_id type;
263 struct timespec time;
Chen Gong06cf91b2011-05-16 11:00:27 -0700264 int failed = 0, rc;
Tony Luckca01d6d2010-12-28 14:25:21 -0800265
266 if (!psi)
267 return;
268
Kees Cookf6f82852011-11-17 12:58:07 -0800269 mutex_lock(&psi->read_mutex);
Kees Cook2174f6d2011-11-18 13:49:00 -0800270 if (psi->open && psi->open(psi))
Chen Gong06cf91b2011-05-16 11:00:27 -0700271 goto out;
272
Kees Cookf6f82852011-11-17 12:58:07 -0800273 while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
274 rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
Luck, Tony6dda9262011-08-11 15:14:39 -0700275 time, psi);
Kees Cookf6f82852011-11-17 12:58:07 -0800276 kfree(buf);
277 buf = NULL;
Luck, Tony6dda9262011-08-11 15:14:39 -0700278 if (rc && (rc != -EEXIST || !quiet))
Tony Luckca01d6d2010-12-28 14:25:21 -0800279 failed++;
280 }
Kees Cook2174f6d2011-11-18 13:49:00 -0800281 if (psi->close)
282 psi->close(psi);
Chen Gong06cf91b2011-05-16 11:00:27 -0700283out:
Kees Cookf6f82852011-11-17 12:58:07 -0800284 mutex_unlock(&psi->read_mutex);
Tony Luckca01d6d2010-12-28 14:25:21 -0800285
286 if (failed)
287 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
288 failed, psi->name);
289}
290
Luck, Tony6dda9262011-08-11 15:14:39 -0700291static void pstore_dowork(struct work_struct *work)
292{
293 pstore_get_records(1);
294}
295
296static void pstore_timefunc(unsigned long dummy)
297{
298 if (pstore_new_entry) {
299 pstore_new_entry = 0;
300 schedule_work(&pstore_work);
301 }
302
Anton Vorontsova3f5f072012-05-26 06:20:28 -0700303 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
Luck, Tony6dda9262011-08-11 15:14:39 -0700304}
305
Matthew Garrettdee28e72011-07-21 16:57:55 -0400306module_param(backend, charp, 0444);
307MODULE_PARM_DESC(backend, "Pstore backend to use");