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/slab.h>
29 #include <linux/uaccess.h>
34 * pstore_lock just protects "psinfo" during
35 * calls to pstore_register()
37 static DEFINE_SPINLOCK(pstore_lock
);
38 static struct pstore_info
*psinfo
;
40 /* How much of the console log to snapshot. /sys/fs/pstore/kmsg_bytes */
41 static unsigned long kmsg_bytes
= 10240;
43 static ssize_t
b_show(struct kobject
*kobj
,
44 struct kobj_attribute
*attr
, char *buf
)
46 return snprintf(buf
, PAGE_SIZE
, "%lu\n", kmsg_bytes
);
49 static ssize_t
b_store(struct kobject
*kobj
, struct kobj_attribute
*attr
,
50 const char *buf
, size_t count
)
52 return (sscanf(buf
, "%lu", &kmsg_bytes
) > 0) ? count
: 0;
55 struct kobj_attribute pstore_kmsg_bytes_attr
=
56 __ATTR(kmsg_bytes
, S_IRUGO
| S_IWUSR
, b_show
, b_store
);
58 /* Tag each group of saved records with a sequence number */
62 * callback from kmsg_dump. (s2,l2) has the most recently
63 * written bytes, older bytes are in (s1,l1). Save as much
64 * as we can from the end of the buffer.
66 static void pstore_dump(struct kmsg_dumper
*dumper
,
67 enum kmsg_dump_reason reason
,
68 const char *s1
, unsigned long l1
,
69 const char *s2
, unsigned long l2
)
71 unsigned long s1_start
, s2_start
;
72 unsigned long l1_cpy
, l2_cpy
;
73 unsigned long size
, total
= 0;
78 mutex_lock(&psinfo
->buf_mutex
);
80 while (total
< kmsg_bytes
) {
82 hsize
= sprintf(dst
, "Oops#%d Part%d\n", oopscount
, part
++);
83 size
= psinfo
->bufsize
- hsize
;
86 l2_cpy
= min(l2
, size
);
87 l1_cpy
= min(l1
, size
- l2_cpy
);
89 if (l1_cpy
+ l2_cpy
== 0)
92 s2_start
= l2
- l2_cpy
;
93 s1_start
= l1
- l1_cpy
;
95 memcpy(dst
, s1
+ s1_start
, l1_cpy
);
96 memcpy(dst
+ l1_cpy
, s2
+ s2_start
, l2_cpy
);
98 id
= psinfo
->write(PSTORE_TYPE_DMESG
, hsize
+ l1_cpy
+ l2_cpy
);
99 if (pstore_is_mounted())
100 pstore_mkfile(PSTORE_TYPE_DMESG
, psinfo
->name
, id
,
101 psinfo
->buf
, hsize
+ l1_cpy
+ l2_cpy
,
102 CURRENT_TIME
, psinfo
->erase
);
105 total
+= l1_cpy
+ l2_cpy
;
107 mutex_unlock(&psinfo
->buf_mutex
);
110 static struct kmsg_dumper pstore_dumper
= {
115 * platform specific persistent storage driver registers with
116 * us here. If pstore is already mounted, call the platform
117 * read function right away to populate the file system. If not
118 * then the pstore mount code will call us later to fill out
121 * Register with kmsg_dump to save last part of console log on panic.
123 int pstore_register(struct pstore_info
*psi
)
125 struct module
*owner
= psi
->owner
;
127 spin_lock(&pstore_lock
);
129 spin_unlock(&pstore_lock
);
133 spin_unlock(&pstore_lock
);
135 if (owner
&& !try_module_get(owner
)) {
140 if (pstore_is_mounted())
141 pstore_get_records();
143 kmsg_dump_register(&pstore_dumper
);
147 EXPORT_SYMBOL_GPL(pstore_register
);
150 * Read all the records from the persistent store. Create and
151 * file files in our filesystem.
153 void pstore_get_records(void)
155 struct pstore_info
*psi
= psinfo
;
158 enum pstore_type_id type
;
159 struct timespec time
;
165 mutex_lock(&psinfo
->buf_mutex
);
166 while ((size
= psi
->read(&id
, &type
, &time
)) > 0) {
167 if (pstore_mkfile(type
, psi
->name
, id
, psi
->buf
, size
,
171 mutex_unlock(&psinfo
->buf_mutex
);
174 printk(KERN_WARNING
"pstore: failed to load %d record(s) from '%s'\n",
179 * Call platform driver to write a record to the
182 int pstore_write(enum pstore_type_id type
, char *buf
, size_t size
)
189 if (size
> psinfo
->bufsize
)
192 mutex_lock(&psinfo
->buf_mutex
);
193 memcpy(psinfo
->buf
, buf
, size
);
194 id
= psinfo
->write(type
, size
);
195 if (pstore_is_mounted())
196 pstore_mkfile(PSTORE_TYPE_DMESG
, psinfo
->name
, id
, psinfo
->buf
,
197 size
, CURRENT_TIME
, psinfo
->erase
);
198 mutex_unlock(&psinfo
->buf_mutex
);
202 EXPORT_SYMBOL_GPL(pstore_write
);