blob: f835a25625ff5c7e74e5834cc9e6057697d02941 [file] [log] [blame]
Tony Luckca01d6d2010-12-28 14:25:21 -08001/*
2 * Persistent Storage - platform driver interface parts.
3 *
4 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
5 *
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.
9 *
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.
14 *
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
18 */
19
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>
30
31#include "internal.h"
32
33/*
34 * pstore_lock just protects "psinfo" during
35 * calls to pstore_register()
36 */
37static DEFINE_SPINLOCK(pstore_lock);
38static struct pstore_info *psinfo;
39
Luck, Tony366f7e72011-03-18 15:33:43 -070040/* How much of the console log to snapshot */
Tony Luckca01d6d2010-12-28 14:25:21 -080041static unsigned long kmsg_bytes = 10240;
42
Luck, Tony366f7e72011-03-18 15:33:43 -070043void pstore_set_kmsg_bytes(int bytes)
Tony Luckca01d6d2010-12-28 14:25:21 -080044{
Luck, Tony366f7e72011-03-18 15:33:43 -070045 kmsg_bytes = bytes;
Tony Luckca01d6d2010-12-28 14:25:21 -080046}
47
Tony Luckca01d6d2010-12-28 14:25:21 -080048/* Tag each group of saved records with a sequence number */
49static int oopscount;
50
Tony Luck9f6af272011-03-22 16:01:49 -070051static char *reason_str[] = {
52 "Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency"
53};
54
Tony Luckca01d6d2010-12-28 14:25:21 -080055/*
56 * callback from kmsg_dump. (s2,l2) has the most recently
57 * written bytes, older bytes are in (s1,l1). Save as much
58 * as we can from the end of the buffer.
59 */
60static void pstore_dump(struct kmsg_dumper *dumper,
61 enum kmsg_dump_reason reason,
62 const char *s1, unsigned long l1,
63 const char *s2, unsigned long l2)
64{
65 unsigned long s1_start, s2_start;
66 unsigned long l1_cpy, l2_cpy;
67 unsigned long size, total = 0;
Tony Luck9f6af272011-03-22 16:01:49 -070068 char *dst, *why;
Tony Luckca01d6d2010-12-28 14:25:21 -080069 u64 id;
70 int hsize, part = 1;
71
Tony Luck9f6af272011-03-22 16:01:49 -070072 if (reason < ARRAY_SIZE(reason_str))
73 why = reason_str[reason];
74 else
75 why = "Unknown";
76
Tony Luckca01d6d2010-12-28 14:25:21 -080077 mutex_lock(&psinfo->buf_mutex);
78 oopscount++;
79 while (total < kmsg_bytes) {
80 dst = psinfo->buf;
Tony Luck9f6af272011-03-22 16:01:49 -070081 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part++);
Tony Luckca01d6d2010-12-28 14:25:21 -080082 size = psinfo->bufsize - hsize;
83 dst += hsize;
84
85 l2_cpy = min(l2, size);
86 l1_cpy = min(l1, size - l2_cpy);
87
88 if (l1_cpy + l2_cpy == 0)
89 break;
90
91 s2_start = l2 - l2_cpy;
92 s1_start = l1 - l1_cpy;
93
94 memcpy(dst, s1 + s1_start, l1_cpy);
95 memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
96
97 id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy);
Tony Luck9f6af272011-03-22 16:01:49 -070098 if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
Tony Luckca01d6d2010-12-28 14:25:21 -080099 pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id,
100 psinfo->buf, hsize + l1_cpy + l2_cpy,
101 CURRENT_TIME, psinfo->erase);
102 l1 -= l1_cpy;
103 l2 -= l2_cpy;
104 total += l1_cpy + l2_cpy;
105 }
106 mutex_unlock(&psinfo->buf_mutex);
107}
108
109static struct kmsg_dumper pstore_dumper = {
110 .dump = pstore_dump,
111};
112
113/*
114 * platform specific persistent storage driver registers with
115 * us here. If pstore is already mounted, call the platform
116 * read function right away to populate the file system. If not
117 * then the pstore mount code will call us later to fill out
118 * the file system.
119 *
120 * Register with kmsg_dump to save last part of console log on panic.
121 */
122int pstore_register(struct pstore_info *psi)
123{
124 struct module *owner = psi->owner;
125
126 spin_lock(&pstore_lock);
127 if (psinfo) {
128 spin_unlock(&pstore_lock);
129 return -EBUSY;
130 }
131 psinfo = psi;
132 spin_unlock(&pstore_lock);
133
134 if (owner && !try_module_get(owner)) {
135 psinfo = NULL;
136 return -EINVAL;
137 }
138
139 if (pstore_is_mounted())
140 pstore_get_records();
141
142 kmsg_dump_register(&pstore_dumper);
143
144 return 0;
145}
146EXPORT_SYMBOL_GPL(pstore_register);
147
148/*
149 * Read all the records from the persistent store. Create and
150 * file files in our filesystem.
151 */
152void pstore_get_records(void)
153{
154 struct pstore_info *psi = psinfo;
155 size_t size;
156 u64 id;
157 enum pstore_type_id type;
158 struct timespec time;
159 int failed = 0;
160
161 if (!psi)
162 return;
163
164 mutex_lock(&psinfo->buf_mutex);
165 while ((size = psi->read(&id, &type, &time)) > 0) {
166 if (pstore_mkfile(type, psi->name, id, psi->buf, size,
167 time, psi->erase))
168 failed++;
169 }
170 mutex_unlock(&psinfo->buf_mutex);
171
172 if (failed)
173 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
174 failed, psi->name);
175}
176
177/*
178 * Call platform driver to write a record to the
179 * persistent store.
180 */
181int pstore_write(enum pstore_type_id type, char *buf, size_t size)
182{
183 u64 id;
184
185 if (!psinfo)
186 return -ENODEV;
187
188 if (size > psinfo->bufsize)
189 return -EFBIG;
190
191 mutex_lock(&psinfo->buf_mutex);
192 memcpy(psinfo->buf, buf, size);
193 id = psinfo->write(type, size);
194 if (pstore_is_mounted())
195 pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
196 size, CURRENT_TIME, psinfo->erase);
197 mutex_unlock(&psinfo->buf_mutex);
198
199 return 0;
200}
201EXPORT_SYMBOL_GPL(pstore_write);