2 * Persistent Storage - platform driver interface parts.
4 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #include <linux/atomic.h>
21 #include <linux/types.h>
22 #include <linux/errno.h>
23 #include <linux/init.h>
24 #include <linux/kmsg_dump.h>
25 #include <linux/module.h>
26 #include <linux/pstore.h>
27 #include <linux/string.h>
28 #include <linux/timer.h>
29 #include <linux/slab.h>
30 #include <linux/uaccess.h>
31 #include <linux/hardirq.h>
32 #include <linux/workqueue.h>
37 * We defer making "oops" entries appear in pstore - see
38 * whether the system is actually still running well enough
39 * to let someone see the entry
41 #define PSTORE_INTERVAL (60 * HZ)
43 static int pstore_new_entry
;
45 static void pstore_timefunc(unsigned long);
46 static DEFINE_TIMER(pstore_timer
, pstore_timefunc
, 0, 0);
48 static void pstore_dowork(struct work_struct
*);
49 static DECLARE_WORK(pstore_work
, pstore_dowork
);
52 * pstore_lock just protects "psinfo" during
53 * calls to pstore_register()
55 static DEFINE_SPINLOCK(pstore_lock
);
56 static struct pstore_info
*psinfo
;
60 /* How much of the console log to snapshot */
61 static unsigned long kmsg_bytes
= 10240;
63 void pstore_set_kmsg_bytes(int bytes
)
68 /* Tag each group of saved records with a sequence number */
71 static const char *get_reason_str(enum kmsg_dump_reason reason
)
80 case KMSG_DUMP_RESTART
:
84 case KMSG_DUMP_POWEROFF
:
92 * callback from kmsg_dump. (s2,l2) has the most recently
93 * written bytes, older bytes are in (s1,l1). Save as much
94 * as we can from the end of the buffer.
96 static void pstore_dump(struct kmsg_dumper
*dumper
,
97 enum kmsg_dump_reason reason
,
98 const char *s1
, unsigned long l1
,
99 const char *s2
, unsigned long l2
)
101 unsigned long s1_start
, s2_start
;
102 unsigned long l1_cpy
, l2_cpy
;
103 unsigned long size
, total
= 0;
108 unsigned int part
= 1;
109 unsigned long flags
= 0;
112 why
= get_reason_str(reason
);
115 is_locked
= spin_trylock(&psinfo
->buf_lock
);
117 pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
119 spin_lock_irqsave(&psinfo
->buf_lock
, flags
);
121 while (total
< kmsg_bytes
) {
123 hsize
= sprintf(dst
, "%s#%d Part%d\n", why
, oopscount
, part
);
124 size
= psinfo
->bufsize
- hsize
;
127 l2_cpy
= min(l2
, size
);
128 l1_cpy
= min(l1
, size
- l2_cpy
);
130 if (l1_cpy
+ l2_cpy
== 0)
133 s2_start
= l2
- l2_cpy
;
134 s1_start
= l1
- l1_cpy
;
136 memcpy(dst
, s1
+ s1_start
, l1_cpy
);
137 memcpy(dst
+ l1_cpy
, s2
+ s2_start
, l2_cpy
);
139 ret
= psinfo
->write(PSTORE_TYPE_DMESG
, reason
, &id
, part
,
140 hsize
+ l1_cpy
+ l2_cpy
, psinfo
);
141 if (ret
== 0 && reason
== KMSG_DUMP_OOPS
&& pstore_is_mounted())
142 pstore_new_entry
= 1;
145 total
+= l1_cpy
+ l2_cpy
;
150 spin_unlock(&psinfo
->buf_lock
);
152 spin_unlock_irqrestore(&psinfo
->buf_lock
, flags
);
155 static struct kmsg_dumper pstore_dumper
= {
160 * platform specific persistent storage driver registers with
161 * us here. If pstore is already mounted, call the platform
162 * read function right away to populate the file system. If not
163 * then the pstore mount code will call us later to fill out
166 * Register with kmsg_dump to save last part of console log on panic.
168 int pstore_register(struct pstore_info
*psi
)
170 struct module
*owner
= psi
->owner
;
172 spin_lock(&pstore_lock
);
174 spin_unlock(&pstore_lock
);
178 if (backend
&& strcmp(backend
, psi
->name
)) {
179 spin_unlock(&pstore_lock
);
184 mutex_init(&psinfo
->read_mutex
);
185 spin_unlock(&pstore_lock
);
187 if (owner
&& !try_module_get(owner
)) {
192 if (pstore_is_mounted())
193 pstore_get_records(0);
195 kmsg_dump_register(&pstore_dumper
);
197 pstore_timer
.expires
= jiffies
+ PSTORE_INTERVAL
;
198 add_timer(&pstore_timer
);
202 EXPORT_SYMBOL_GPL(pstore_register
);
205 * Read all the records from the persistent store. Create
206 * files in our filesystem. Don't warn about -EEXIST errors
207 * when we are re-scanning the backing store looking to add new
210 void pstore_get_records(int quiet
)
212 struct pstore_info
*psi
= psinfo
;
216 enum pstore_type_id type
;
217 struct timespec time
;
223 mutex_lock(&psi
->read_mutex
);
224 if (psi
->open
&& psi
->open(psi
))
227 while ((size
= psi
->read(&id
, &type
, &time
, &buf
, psi
)) > 0) {
228 rc
= pstore_mkfile(type
, psi
->name
, id
, buf
, (size_t)size
,
232 if (rc
&& (rc
!= -EEXIST
|| !quiet
))
238 mutex_unlock(&psi
->read_mutex
);
241 printk(KERN_WARNING
"pstore: failed to load %d record(s) from '%s'\n",
245 static void pstore_dowork(struct work_struct
*work
)
247 pstore_get_records(1);
250 static void pstore_timefunc(unsigned long dummy
)
252 if (pstore_new_entry
) {
253 pstore_new_entry
= 0;
254 schedule_work(&pstore_work
);
257 mod_timer(&pstore_timer
, jiffies
+ PSTORE_INTERVAL
);
260 module_param(backend
, charp
, 0444);
261 MODULE_PARM_DESC(backend
, "Pstore backend to use");