2 * Persistent Storage - platform driver interface parts.
4 * Copyright (C) 2007-2008 Google, Inc.
5 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
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.
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.
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
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>
26 #include <linux/console.h>
27 #include <linux/module.h>
28 #include <linux/pstore.h>
29 #include <linux/string.h>
30 #include <linux/timer.h>
31 #include <linux/slab.h>
32 #include <linux/uaccess.h>
33 #include <linux/hardirq.h>
34 #include <linux/jiffies.h>
35 #include <linux/workqueue.h>
40 * 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
44 static int pstore_update_ms = -1;
45 module_param_named(update_ms, pstore_update_ms, int, 0600);
46 MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
47 "(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)");
51 static int pstore_new_entry;
53 static void pstore_timefunc(unsigned long);
54 static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
56 static void pstore_dowork(struct work_struct *);
57 static DECLARE_WORK(pstore_work, pstore_dowork);
60 * pstore_lock just protects "psinfo" during
61 * calls to pstore_register()
63 static DEFINE_SPINLOCK(pstore_lock);
64 static struct pstore_info *psinfo;
68 /* How much of the console log to snapshot */
69 static unsigned long kmsg_bytes = 10240;
71 void pstore_set_kmsg_bytes(int bytes)
76 /* Tag each group of saved records with a sequence number */
79 static const char *get_reason_str(enum kmsg_dump_reason reason)
88 case KMSG_DUMP_RESTART:
92 case KMSG_DUMP_POWEROFF:
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.
104 static void pstore_dump(struct kmsg_dumper *dumper,
105 enum kmsg_dump_reason reason,
106 const char *s1, unsigned long l1,
107 const char *s2, unsigned long l2)
109 unsigned long s1_start, s2_start;
110 unsigned long l1_cpy, l2_cpy;
111 unsigned long size, total = 0;
116 unsigned int part = 1;
117 unsigned long flags = 0;
120 why = get_reason_str(reason);
123 is_locked = spin_trylock(&psinfo->buf_lock);
125 pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
127 spin_lock_irqsave(&psinfo->buf_lock, flags);
129 while (total < kmsg_bytes) {
131 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
132 size = psinfo->bufsize - hsize;
135 l2_cpy = min(l2, size);
136 l1_cpy = min(l1, size - l2_cpy);
138 if (l1_cpy + l2_cpy == 0)
141 s2_start = l2 - l2_cpy;
142 s1_start = l1 - l1_cpy;
144 memcpy(dst, s1 + s1_start, l1_cpy);
145 memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
147 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
148 hsize + l1_cpy + l2_cpy, psinfo);
149 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
150 pstore_new_entry = 1;
153 total += l1_cpy + l2_cpy;
158 spin_unlock(&psinfo->buf_lock);
160 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
163 static struct kmsg_dumper pstore_dumper = {
167 #ifdef CONFIG_PSTORE_CONSOLE
168 static void pstore_console_write(struct console *con, const char *s, unsigned c)
170 const char *e = s + c;
175 if (c > psinfo->bufsize)
177 spin_lock_irqsave(&psinfo->buf_lock, flags);
178 memcpy(psinfo->buf, s, c);
179 psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
180 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
186 static struct console pstore_console = {
188 .write = pstore_console_write,
189 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
193 static void pstore_register_console(void)
195 register_console(&pstore_console);
198 static void pstore_register_console(void) {}
202 * platform specific persistent storage driver registers with
203 * us here. If pstore is already mounted, call the platform
204 * read function right away to populate the file system. If not
205 * then the pstore mount code will call us later to fill out
208 * Register with kmsg_dump to save last part of console log on panic.
210 int pstore_register(struct pstore_info *psi)
212 struct module *owner = psi->owner;
214 spin_lock(&pstore_lock);
216 spin_unlock(&pstore_lock);
220 if (backend && strcmp(backend, psi->name)) {
221 spin_unlock(&pstore_lock);
226 mutex_init(&psinfo->read_mutex);
227 spin_unlock(&pstore_lock);
229 if (owner && !try_module_get(owner)) {
234 if (pstore_is_mounted())
235 pstore_get_records(0);
237 kmsg_dump_register(&pstore_dumper);
238 pstore_register_console();
240 if (pstore_update_ms >= 0) {
241 pstore_timer.expires = jiffies +
242 msecs_to_jiffies(pstore_update_ms);
243 add_timer(&pstore_timer);
248 EXPORT_SYMBOL_GPL(pstore_register);
251 * 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
256 void pstore_get_records(int quiet)
258 struct pstore_info *psi = psinfo;
262 enum pstore_type_id type;
263 struct timespec time;
269 mutex_lock(&psi->read_mutex);
270 if (psi->open && psi->open(psi))
273 while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
274 rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
278 if (rc && (rc != -EEXIST || !quiet))
284 mutex_unlock(&psi->read_mutex);
287 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
291 static void pstore_dowork(struct work_struct *work)
293 pstore_get_records(1);
296 static void pstore_timefunc(unsigned long dummy)
298 if (pstore_new_entry) {
299 pstore_new_entry = 0;
300 schedule_work(&pstore_work);
303 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
306 module_param(backend, charp, 0444);
307 MODULE_PARM_DESC(backend, "Pstore backend to use");