[linux-block.git] / fs / pstore / platform.c

/*
 * 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;

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 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;
	unsigned int	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, part,
				   hsize + l1_cpy + l2_cpy, psinfo);
		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);
		l1 -= l1_cpy;
		l2 -= l2_cpy;
		total += l1_cpy + l2_cpy;
		part++;
	}
	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;
	}

	if (backend && strcmp(backend, psi->name)) {
		spin_unlock(&pstore_lock);
		return -EINVAL;
	}

	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, psi)) > 0) {
		if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
				  time, psi))
			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, 0, size, psinfo);
	if (pstore_is_mounted())
		pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
			      size, CURRENT_TIME, psinfo);
	mutex_unlock(&psinfo->buf_mutex);

	return 0;
}
EXPORT_SYMBOL_GPL(pstore_write);

module_param(backend, charp, 0444);
MODULE_PARM_DESC(backend, "Pstore backend to use");
Commit	Line	Data
ca01d6dd TL	1	/*
	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	*/
	37	static DEFINE_SPINLOCK(pstore_lock);
	38	static struct pstore_info *psinfo;
	39
dee28e72 MG	40	static char *backend;
dee28e72 MG	41
366f7e7a	42	/* How much of the console log to snapshot */
ca01d6dd TL	43	static unsigned long kmsg_bytes = 10240;
ca01d6dd TL	44
366f7e7a	45	void pstore_set_kmsg_bytes(int bytes)
ca01d6dd	46	{
366f7e7a	47	kmsg_bytes = bytes;
ca01d6dd TL	48	}
ca01d6dd TL	49
ca01d6dd TL	50	/* Tag each group of saved records with a sequence number */
	51	static int oopscount;
	52
9f6af27f TL	53	static char *reason_str[] = {
	54	"Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency"
	55	};
	56
ca01d6dd TL	57	/*
	58	* callback from kmsg_dump. (s2,l2) has the most recently
	59	* written bytes, older bytes are in (s1,l1). Save as much
	60	* as we can from the end of the buffer.
	61	*/
	62	static void pstore_dump(struct kmsg_dumper *dumper,
	63	enum kmsg_dump_reason reason,
	64	const char *s1, unsigned long l1,
	65	const char *s2, unsigned long l2)
	66	{
	67	unsigned long s1_start, s2_start;
	68	unsigned long l1_cpy, l2_cpy;
	69	unsigned long size, total = 0;
9f6af27f	70	char dst, why;
ca01d6dd	71	u64 id;
b94fdd07 MG	72	int hsize;
b94fdd07 MG	73	unsigned int part = 1;
ca01d6dd	74
9f6af27f TL	75	if (reason < ARRAY_SIZE(reason_str))
	76	why = reason_str[reason];
	77	else
	78	why = "Unknown";
	79
ca01d6dd TL	80	mutex_lock(&psinfo->buf_mutex);
	81	oopscount++;
	82	while (total < kmsg_bytes) {
	83	dst = psinfo->buf;
56280682	84	hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
ca01d6dd TL	85	size = psinfo->bufsize - hsize;
	86	dst += hsize;
	87
	88	l2_cpy = min(l2, size);
	89	l1_cpy = min(l1, size - l2_cpy);
	90
	91	if (l1_cpy + l2_cpy == 0)
	92	break;
	93
	94	s2_start = l2 - l2_cpy;
	95	s1_start = l1 - l1_cpy;
	96
	97	memcpy(dst, s1 + s1_start, l1_cpy);
	98	memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
	99
56280682 MG	100	id = psinfo->write(PSTORE_TYPE_DMESG, part,
56280682 MG	101	hsize + l1_cpy + l2_cpy, psinfo);
9f6af27f	102	if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
ca01d6dd TL	103	pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id,
ca01d6dd TL	104	psinfo->buf, hsize + l1_cpy + l2_cpy,
638c1fd3	105	CURRENT_TIME, psinfo);
ca01d6dd TL	106	l1 -= l1_cpy;
	107	l2 -= l2_cpy;
	108	total += l1_cpy + l2_cpy;
56280682	109	part++;
ca01d6dd TL	110	}
	111	mutex_unlock(&psinfo->buf_mutex);
	112	}
	113
	114	static struct kmsg_dumper pstore_dumper = {
	115	.dump = pstore_dump,
	116	};
	117
	118	/*
	119	* platform specific persistent storage driver registers with
	120	* us here. If pstore is already mounted, call the platform
	121	* read function right away to populate the file system. If not
	122	* then the pstore mount code will call us later to fill out
	123	* the file system.
	124	*
	125	* Register with kmsg_dump to save last part of console log on panic.
	126	*/
	127	int pstore_register(struct pstore_info *psi)
	128	{
	129	struct module *owner = psi->owner;
	130
	131	spin_lock(&pstore_lock);
	132	if (psinfo) {
	133	spin_unlock(&pstore_lock);
	134	return -EBUSY;
	135	}
dee28e72 MG	136
	137	if (backend && strcmp(backend, psi->name)) {
	138	spin_unlock(&pstore_lock);
	139	return -EINVAL;
	140	}
	141
ca01d6dd TL	142	psinfo = psi;
	143	spin_unlock(&pstore_lock);
	144
	145	if (owner && !try_module_get(owner)) {
	146	psinfo = NULL;
	147	return -EINVAL;
	148	}
	149
	150	if (pstore_is_mounted())
	151	pstore_get_records();
	152
	153	kmsg_dump_register(&pstore_dumper);
	154
	155	return 0;
	156	}
	157	EXPORT_SYMBOL_GPL(pstore_register);
	158
	159	/*
	160	* Read all the records from the persistent store. Create and
	161	* file files in our filesystem.
	162	*/
	163	void pstore_get_records(void)
	164	{
	165	struct pstore_info *psi = psinfo;
8d38d74b	166	ssize_t size;
ca01d6dd TL	167	u64 id;
	168	enum pstore_type_id type;
	169	struct timespec time;
06cf91b4	170	int failed = 0, rc;
ca01d6dd TL	171
	172	if (!psi)
	173	return;
	174
	175	mutex_lock(&psinfo->buf_mutex);
06cf91b4 CG	176	rc = psi->open(psi);
	177	if (rc)
	178	goto out;
	179
638c1fd3	180	while ((size = psi->read(&id, &type, &time, psi)) > 0) {
8d38d74b	181	if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
638c1fd3	182	time, psi))
ca01d6dd TL	183	failed++;
ca01d6dd TL	184	}
06cf91b4 CG	185	psi->close(psi);
06cf91b4 CG	186	out:
ca01d6dd TL	187	mutex_unlock(&psinfo->buf_mutex);
	188
	189	if (failed)
	190	printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
	191	failed, psi->name);
	192	}
	193
	194	/*
	195	* Call platform driver to write a record to the
	196	* persistent store.
	197	*/
	198	int pstore_write(enum pstore_type_id type, char *buf, size_t size)
	199	{
	200	u64 id;
	201
	202	if (!psinfo)
	203	return -ENODEV;
	204
	205	if (size > psinfo->bufsize)
	206	return -EFBIG;
	207
	208	mutex_lock(&psinfo->buf_mutex);
	209	memcpy(psinfo->buf, buf, size);
56280682	210	id = psinfo->write(type, 0, size, psinfo);
ca01d6dd TL	211	if (pstore_is_mounted())
ca01d6dd TL	212	pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
638c1fd3	213	size, CURRENT_TIME, psinfo);
ca01d6dd TL	214	mutex_unlock(&psinfo->buf_mutex);
	215
	216	return 0;
	217	}
	218	EXPORT_SYMBOL_GPL(pstore_write);
dee28e72 MG	219
	220	module_param(backend, charp, 0444);
	221	MODULE_PARM_DESC(backend, "Pstore backend to use");