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);