/*
* Persistent Storage - platform driver interface parts.
*
* Copyright (C) 2007-2008 Google, Inc.
* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/atomic.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/kmsg_dump.h>
#include <linux/console.h>
#include <linux/module.h>
#include <linux/pstore.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <linux/jiffies.h>
#include <linux/workqueue.h>
#include "internal.h"
/*
* We defer making "oops" entries appear in pstore - see
* whether the system is actually still running well enough
* to let someone see the entry
*/
static int pstore_update_ms = -1;
module_param_named(update_ms, pstore_update_ms, int, 0600);
MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
"(default is -1, which means runtime updates are disabled; "
"enabling this option is not safe, it may lead to further "
"corruption on Oopses)");
static int pstore_new_entry;
static void pstore_timefunc(unsigned long);
static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
static void pstore_dowork(struct work_struct *);
static DECLARE_WORK(pstore_work, pstore_dowork);
/*
* pstore_lock just protects "psinfo" during
* calls to pstore_register()
*/
static DEFINE_SPINLOCK(pstore_lock);
struct pstore_info *psinfo;
static char *backend;
/* How much of the console log to snapshot */
static unsigned long kmsg_bytes = 10240;
void pstore_set_kmsg_bytes(int bytes)
{
kmsg_bytes = bytes;
}
/* Tag each group of saved records with a sequence number */
static int oopscount;
static const char *get_reason_str(enum kmsg_dump_reason reason)
{
switch (reason) {
case KMSG_DUMP_PANIC:
return "Panic";
case KMSG_DUMP_OOPS:
return "Oops";
case KMSG_DUMP_EMERG:
return "Emergency";
case KMSG_DUMP_RESTART:
return "Restart";
case KMSG_DUMP_HALT:
return "Halt";
case KMSG_DUMP_POWEROFF:
return "Poweroff";
default:
return "Unknown";
}
}
/*
* callback from kmsg_dump. (s2,l2) has the most recently
* written bytes, older bytes are in (s1,l1). Save as much
* as we can from the end of the buffer.
*/
static void pstore_dump(struct kmsg_dumper *dumper,
enum kmsg_dump_reason reason)
{
unsigned long total = 0;
const char *why;
u64 id;
unsigned int part = 1;
unsigned long flags = 0;
int is_locked = 0;
int ret;
why = get_reason_str(reason);
if (in_nmi()) {
is_locked = spin_trylock(&psinfo->buf_lock);
if (!is_locked)
pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
} else
spin_lock_irqsave(&psinfo->buf_lock, flags);
oopscount++;
while (total < kmsg_bytes) {
char *dst;
unsigned long size;
int hsize;
size_t len;
dst = psinfo->buf;
hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
size = psinfo->bufsize - hsize;
dst += hsize;
if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
break;
ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
hsize + len, psinfo);
if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
pstore_new_entry = 1;
total += hsize + len;
part++;
}
if (in_nmi()) {
if (is_locked)
spin_unlock(&psinfo->buf_lock);
} else
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
}
static struct kmsg_dumper pstore_dumper = {
.dump = pstore_dump,
};
#ifdef CONFIG_PSTORE_CONSOLE
static void pstore_console_write(struct console *con, const char *s, unsigned c)
{
const char *e = s + c;
while (s < e) {
unsigned long flags;
if (c > psinfo->bufsize)
c = psinfo->bufsize;
spin_lock_irqsave(&psinfo->buf_lock, flags);
memcpy(psinfo->buf, s, c);
psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
spin_unlock_irqrestore(&psinfo->buf_lock, flags);
s += c;
c = e - s;
}
}
static struct console pstore_console = {
.name = "pstore",
.write = pstore_console_write,
.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
.index = -1,
};
static void pstore_register_console(void)
{
register_console(&pstore_console);
}
#else
static void pstore_register_console(void) {}
#endif
static int pstore_write_compat(enum pstore_type_id type,
enum kmsg_dump_reason reason,
u64 *id, unsigned int part,
size_t size, struct pstore_info *psi)
{
return psi->write_buf(type, reason, id, part, psinfo->buf, size, psi);
}
/*
* platform specific persistent storage driver registers with
* us here. If pstore is already mounted, call the platform
* read function right away to populate the file system. If not
* then the pstore mount code will call us later to fill out
* the file system.
*
* Register with kmsg_dump to save last part of console log on panic.
*/
int pstore_register(struct pstore_info *psi)
{
struct module *owner = psi->owner;
spin_lock(&pstore_lock);
if (psinfo) {
spin_unlock(&pstore_lock);
return -EBUSY;
}
if (backend && strcmp(backend, psi->name)) {
spin_unlock(&pstore_lock);
return -EINVAL;
}
if (!psi->write)
psi->write = pstore_write_compat;
psinfo = psi;
mutex_init(&psinfo->read_mutex);
spin_unlock(&pstore_lock);
if (owner && !try_module_get(owner)) {
psinfo = NULL;
return -EINVAL;
}
if (pstore_is_mounted())
pstore_get_records(0);
kmsg_dump_register(&pstore_dumper);
pstore_register_console();
if (pstore_update_ms >= 0) {
pstore_timer.expires = jiffies +
msecs_to_jiffies(pstore_update_ms);
add_timer(&pstore_timer);
}
return 0;
}
EXPORT_SYMBOL_GPL(pstore_register);
/*
* Read all the records from the persistent store. Create
* files in our filesystem. Don't warn about -EEXIST errors
* when we are re-scanning the backing store looking to add new
* error records.
*/
void pstore_get_records(int quiet)
{
struct pstore_info *psi = psinfo;
char *buf = NULL;
ssize_t size;
u64 id;
enum pstore_type_id type;
struct timespec time;
int failed = 0, rc;
if (!psi)
return;
mutex_lock(&psi->read_mutex);
if (psi->open && psi->open(psi))
goto out;
while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
time, psi);
kfree(buf);
buf = NULL;
if (rc && (rc != -EEXIST || !quiet))
failed++;
}
if (psi->close)
psi->close(psi);
out:
mutex_unlock(&psi->read_mutex);
if (failed)
printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
failed, psi->name);
}
static void pstore_dowork(struct work_struct *work)
{
pstore_get_records(1);
}
static void pstore_timefunc(unsigned long dummy)
{
if (pstore_new_entry) {
pstore_new_entry = 0;
schedule_work(&pstore_work);
}
mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
}
module_param(backend, charp, 0444);
MODULE_PARM_DESC(backend, "Pstore backend to use");
