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 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)
107 unsigned long total = 0;
110 unsigned int part = 1;
111 unsigned long flags = 0;
115 why = get_reason_str(reason);
118 is_locked = spin_trylock(&psinfo->buf_lock);
120 pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
122 spin_lock_irqsave(&psinfo->buf_lock, flags);
124 while (total < kmsg_bytes) {
131 hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
132 size = psinfo->bufsize - hsize;
135 if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
138 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
139 oopscount, hsize + len, psinfo);
140 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
141 pstore_new_entry = 1;
143 total += hsize + len;
148 spin_unlock(&psinfo->buf_lock);
150 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
153 static struct kmsg_dumper pstore_dumper = {
157 #ifdef CONFIG_PSTORE_CONSOLE
158 static void pstore_console_write(struct console *con, const char *s, unsigned c)
160 const char *e = s + c;
166 if (c > psinfo->bufsize)
169 if (oops_in_progress) {
170 if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
173 spin_lock_irqsave(&psinfo->buf_lock, flags);
175 memcpy(psinfo->buf, s, c);
176 psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, c, psinfo);
177 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
183 static struct console pstore_console = {
185 .write = pstore_console_write,
186 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
190 static void pstore_register_console(void)
192 register_console(&pstore_console);
195 static void pstore_register_console(void) {}
198 static int pstore_write_compat(enum pstore_type_id type,
199 enum kmsg_dump_reason reason,
200 u64 *id, unsigned int part, int count,
201 size_t size, struct pstore_info *psi)
203 return psi->write_buf(type, reason, id, part, psinfo->buf, size, psi);
207 * platform specific persistent storage driver registers with
208 * us here. If pstore is already mounted, call the platform
209 * read function right away to populate the file system. If not
210 * then the pstore mount code will call us later to fill out
213 * Register with kmsg_dump to save last part of console log on panic.
215 int pstore_register(struct pstore_info *psi)
217 struct module *owner = psi->owner;
219 spin_lock(&pstore_lock);
221 spin_unlock(&pstore_lock);
225 if (backend && strcmp(backend, psi->name)) {
226 spin_unlock(&pstore_lock);
231 psi->write = pstore_write_compat;
233 mutex_init(&psinfo->read_mutex);
234 spin_unlock(&pstore_lock);
236 if (owner && !try_module_get(owner)) {
241 if (pstore_is_mounted())
242 pstore_get_records(0);
244 kmsg_dump_register(&pstore_dumper);
245 pstore_register_console();
246 pstore_register_ftrace();
248 if (pstore_update_ms >= 0) {
249 pstore_timer.expires = jiffies +
250 msecs_to_jiffies(pstore_update_ms);
251 add_timer(&pstore_timer);
256 EXPORT_SYMBOL_GPL(pstore_register);
259 * Read all the records from the persistent store. Create
260 * files in our filesystem. Don't warn about -EEXIST errors
261 * when we are re-scanning the backing store looking to add new
264 void pstore_get_records(int quiet)
266 struct pstore_info *psi = psinfo;
271 enum pstore_type_id type;
272 struct timespec time;
278 mutex_lock(&psi->read_mutex);
279 if (psi->open && psi->open(psi))
282 while ((size = psi->read(&id, &type, &count, &time, &buf, psi)) > 0) {
283 rc = pstore_mkfile(type, psi->name, id, count, buf,
284 (size_t)size, time, psi);
287 if (rc && (rc != -EEXIST || !quiet))
293 mutex_unlock(&psi->read_mutex);
296 printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
300 static void pstore_dowork(struct work_struct *work)
302 pstore_get_records(1);
305 static void pstore_timefunc(unsigned long dummy)
307 if (pstore_new_entry) {
308 pstore_new_entry = 0;
309 schedule_work(&pstore_work);
312 mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
315 module_param(backend, charp, 0444);
316 MODULE_PARM_DESC(backend, "Pstore backend to use");