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/*
* Persistent Storage - platform driver interface parts.
*
* 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/module.h>
#include <linux/pstore.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include "internal.h"
/*
* pstore_lock just protects "psinfo" during
* calls to pstore_register()
*/
static DEFINE_SPINLOCK(pstore_lock);
static struct pstore_info *psinfo;
/* 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 char *reason_str[] = {
"Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency"
};
/*
* 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,
const char *s1, unsigned long l1,
const char *s2, unsigned long l2)
{
unsigned long s1_start, s2_start;
unsigned long l1_cpy, l2_cpy;
unsigned long size, total = 0;
char *dst, *why;
u64 id;
int hsize, part = 1;
if (reason < ARRAY_SIZE(reason_str))
why = reason_str[reason];
else
why = "Unknown";
mutex_lock(&psinfo->buf_mutex);
oopscount++;
while (total < kmsg_bytes) {
dst = psinfo->buf;
hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part++);
size = psinfo->bufsize - hsize;
dst += hsize;
l2_cpy = min(l2, size);
l1_cpy = min(l1, size - l2_cpy);
if (l1_cpy + l2_cpy == 0)
break;
s2_start = l2 - l2_cpy;
s1_start = l1 - l1_cpy;
memcpy(dst, s1 + s1_start, l1_cpy);
memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy);
if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id,
psinfo->buf, hsize + l1_cpy + l2_cpy,
CURRENT_TIME, psinfo->erase);
l1 -= l1_cpy;
l2 -= l2_cpy;
total += l1_cpy + l2_cpy;
}
mutex_unlock(&psinfo->buf_mutex);
}
static struct kmsg_dumper pstore_dumper = {
.dump = pstore_dump,
};
/*
* 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;
}
psinfo = psi;
spin_unlock(&pstore_lock);
if (owner && !try_module_get(owner)) {
psinfo = NULL;
return -EINVAL;
}
if (pstore_is_mounted())
pstore_get_records();
kmsg_dump_register(&pstore_dumper);
return 0;
}
EXPORT_SYMBOL_GPL(pstore_register);
/*
* Read all the records from the persistent store. Create and
* file files in our filesystem.
*/
void pstore_get_records(void)
{
struct pstore_info *psi = psinfo;
ssize_t size;
u64 id;
enum pstore_type_id type;
struct timespec time;
int failed = 0, rc;
if (!psi)
return;
mutex_lock(&psinfo->buf_mutex);
rc = psi->open(psi);
if (rc)
goto out;
while ((size = psi->read(&id, &type, &time)) > 0) {
if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
time, psi->erase))
failed++;
}
psi->close(psi);
out:
mutex_unlock(&psinfo->buf_mutex);
if (failed)
printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
failed, psi->name);
}
/*
* Call platform driver to write a record to the
* persistent store.
*/
int pstore_write(enum pstore_type_id type, char *buf, size_t size)
{
u64 id;
if (!psinfo)
return -ENODEV;
if (size > psinfo->bufsize)
return -EFBIG;
mutex_lock(&psinfo->buf_mutex);
memcpy(psinfo->buf, buf, size);
id = psinfo->write(type, size);
if (pstore_is_mounted())
pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
size, CURRENT_TIME, psinfo->erase);
mutex_unlock(&psinfo->buf_mutex);
return 0;
}
EXPORT_SYMBOL_GPL(pstore_write);
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