[mirror_ubuntu-bionic-kernel.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;

/* 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;
	size_t			size;
	u64			id;
	enum pstore_type_id	type;
	struct timespec		time;
	int			failed = 0;

	if (!psi)
		return;

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