[mirror_ubuntu-artful-kernel.git] / fs / pstore / platform.c

/*
 * 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 = 60000;
module_param_named(update_ms, pstore_update_ms, int, 0600);
MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
		 "(default is 60000; -1 means runtime updates are disabled)");

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);
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 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,
	    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;
	const char	*why;
	u64		id;
	int		hsize, ret;
	unsigned int	part = 1;
	unsigned long	flags = 0;
	int		is_locked = 0;

	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) {
		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);

		ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
				   hsize + l1_cpy + l2_cpy, psinfo);
		if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
			pstore_new_entry = 1;
		l1 -= l1_cpy;
		l2 -= l2_cpy;
		total += l1_cpy + l2_cpy;
		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

/*
 * 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;
	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");
Commit	Line	Data
ca01d6dd TL	1	/*
	2	* Persistent Storage - platform driver interface parts.
	3	*
f29e5956	4	* Copyright (C) 2007-2008 Google, Inc.
ca01d6dd TL	5	* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
	6	*
	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.
	10	*
	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.
	15	*
	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
	19	*/
	20
	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>
f29e5956	26	#include <linux/console.h>
ca01d6dd TL	27	#include <linux/module.h>
	28	#include <linux/pstore.h>
	29	#include <linux/string.h>
6dda9266	30	#include <linux/timer.h>
ca01d6dd TL	31	#include <linux/slab.h>
ca01d6dd TL	32	#include <linux/uaccess.h>
abd4d558	33	#include <linux/hardirq.h>
a3f5f075	34	#include <linux/jiffies.h>
6dda9266	35	#include <linux/workqueue.h>
ca01d6dd TL	36
	37	#include "internal.h"
	38
6dda9266 TL	39	/*
	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
	43	*/
a3f5f075 AV	44	static int pstore_update_ms = 60000;
	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 60000; -1 means runtime updates are disabled)");
6dda9266 TL	48
	49	static int pstore_new_entry;
	50
	51	static void pstore_timefunc(unsigned long);
	52	static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
	53
	54	static void pstore_dowork(struct work_struct *);
	55	static DECLARE_WORK(pstore_work, pstore_dowork);
	56
ca01d6dd TL	57	/*
	58	* pstore_lock just protects "psinfo" during
	59	* calls to pstore_register()
	60	*/
	61	static DEFINE_SPINLOCK(pstore_lock);
	62	static struct pstore_info *psinfo;
	63
dee28e72 MG	64	static char *backend;
dee28e72 MG	65
366f7e7a	66	/* How much of the console log to snapshot */
ca01d6dd TL	67	static unsigned long kmsg_bytes = 10240;
ca01d6dd TL	68
366f7e7a	69	void pstore_set_kmsg_bytes(int bytes)
ca01d6dd	70	{
366f7e7a	71	kmsg_bytes = bytes;
ca01d6dd TL	72	}
ca01d6dd TL	73
ca01d6dd TL	74	/* Tag each group of saved records with a sequence number */
	75	static int oopscount;
	76
381b872c SA	77	static const char *get_reason_str(enum kmsg_dump_reason reason)
	78	{
	79	switch (reason) {
	80	case KMSG_DUMP_PANIC:
	81	return "Panic";
	82	case KMSG_DUMP_OOPS:
	83	return "Oops";
	84	case KMSG_DUMP_EMERG:
	85	return "Emergency";
	86	case KMSG_DUMP_RESTART:
	87	return "Restart";
	88	case KMSG_DUMP_HALT:
	89	return "Halt";
	90	case KMSG_DUMP_POWEROFF:
	91	return "Poweroff";
	92	default:
	93	return "Unknown";
	94	}
	95	}
9f6af27f	96
ca01d6dd TL	97	/*
	98	* callback from kmsg_dump. (s2,l2) has the most recently
	99	* written bytes, older bytes are in (s1,l1). Save as much
	100	* as we can from the end of the buffer.
	101	*/
	102	static void pstore_dump(struct kmsg_dumper *dumper,
	103	enum kmsg_dump_reason reason,
	104	const char *s1, unsigned long l1,
	105	const char *s2, unsigned long l2)
	106	{
	107	unsigned long s1_start, s2_start;
	108	unsigned long l1_cpy, l2_cpy;
	109	unsigned long size, total = 0;
381b872c SA	110	char *dst;
381b872c SA	111	const char *why;
ca01d6dd	112	u64 id;
b238b8fa	113	int hsize, ret;
b94fdd07	114	unsigned int part = 1;
abd4d558 DZ	115	unsigned long flags = 0;
abd4d558 DZ	116	int is_locked = 0;
ca01d6dd	117
381b872c	118	why = get_reason_str(reason);
9f6af27f	119
abd4d558 DZ	120	if (in_nmi()) {
	121	is_locked = spin_trylock(&psinfo->buf_lock);
	122	if (!is_locked)
	123	pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
	124	} else
	125	spin_lock_irqsave(&psinfo->buf_lock, flags);
ca01d6dd TL	126	oopscount++;
	127	while (total < kmsg_bytes) {
	128	dst = psinfo->buf;
56280682	129	hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
ca01d6dd TL	130	size = psinfo->bufsize - hsize;
	131	dst += hsize;
	132
	133	l2_cpy = min(l2, size);
	134	l1_cpy = min(l1, size - l2_cpy);
	135
	136	if (l1_cpy + l2_cpy == 0)
	137	break;
	138
	139	s2_start = l2 - l2_cpy;
	140	s1_start = l1 - l1_cpy;
	141
	142	memcpy(dst, s1 + s1_start, l1_cpy);
	143	memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
	144
3d6d8d20	145	ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
56280682	146	hsize + l1_cpy + l2_cpy, psinfo);
b238b8fa	147	if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
6dda9266	148	pstore_new_entry = 1;
ca01d6dd TL	149	l1 -= l1_cpy;
	150	l2 -= l2_cpy;
	151	total += l1_cpy + l2_cpy;
56280682	152	part++;
ca01d6dd	153	}
abd4d558 DZ	154	if (in_nmi()) {
	155	if (is_locked)
	156	spin_unlock(&psinfo->buf_lock);
	157	} else
	158	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
ca01d6dd TL	159	}
	160
	161	static struct kmsg_dumper pstore_dumper = {
	162	.dump = pstore_dump,
	163	};
	164
f29e5956 AV	165	#ifdef CONFIG_PSTORE_CONSOLE
	166	static void pstore_console_write(struct console con, const char s, unsigned c)
	167	{
	168	const char *e = s + c;
	169
	170	while (s < e) {
	171	unsigned long flags;
	172
	173	if (c > psinfo->bufsize)
	174	c = psinfo->bufsize;
	175	spin_lock_irqsave(&psinfo->buf_lock, flags);
	176	memcpy(psinfo->buf, s, c);
	177	psinfo->write(PSTORE_TYPE_CONSOLE, 0, NULL, 0, c, psinfo);
	178	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
	179	s += c;
	180	c = e - s;
	181	}
	182	}
	183
	184	static struct console pstore_console = {
	185	.name = "pstore",
	186	.write = pstore_console_write,
	187	.flags = CON_PRINTBUFFER \| CON_ENABLED \| CON_ANYTIME,
	188	.index = -1,
	189	};
	190
	191	static void pstore_register_console(void)
	192	{
	193	register_console(&pstore_console);
	194	}
	195	#else
	196	static void pstore_register_console(void) {}
	197	#endif
	198
ca01d6dd TL	199	/*
	200	* platform specific persistent storage driver registers with
	201	* us here. If pstore is already mounted, call the platform
	202	* read function right away to populate the file system. If not
	203	* then the pstore mount code will call us later to fill out
	204	* the file system.
	205	*
	206	* Register with kmsg_dump to save last part of console log on panic.
	207	*/
	208	int pstore_register(struct pstore_info *psi)
	209	{
	210	struct module *owner = psi->owner;
	211
	212	spin_lock(&pstore_lock);
	213	if (psinfo) {
	214	spin_unlock(&pstore_lock);
	215	return -EBUSY;
	216	}
dee28e72 MG	217
	218	if (backend && strcmp(backend, psi->name)) {
	219	spin_unlock(&pstore_lock);
	220	return -EINVAL;
	221	}
	222
ca01d6dd	223	psinfo = psi;
f6f82851	224	mutex_init(&psinfo->read_mutex);
ca01d6dd TL	225	spin_unlock(&pstore_lock);
	226
	227	if (owner && !try_module_get(owner)) {
	228	psinfo = NULL;
	229	return -EINVAL;
	230	}
	231
	232	if (pstore_is_mounted())
6dda9266	233	pstore_get_records(0);
ca01d6dd TL	234
ca01d6dd TL	235	kmsg_dump_register(&pstore_dumper);
f29e5956	236	pstore_register_console();
ca01d6dd	237
a3f5f075 AV	238	if (pstore_update_ms >= 0) {
	239	pstore_timer.expires = jiffies +
	240	msecs_to_jiffies(pstore_update_ms);
	241	add_timer(&pstore_timer);
	242	}
6dda9266	243
ca01d6dd TL	244	return 0;
	245	}
	246	EXPORT_SYMBOL_GPL(pstore_register);
	247
	248	/*
6dda9266 TL	249	* Read all the records from the persistent store. Create
	250	* files in our filesystem. Don't warn about -EEXIST errors
	251	* when we are re-scanning the backing store looking to add new
	252	* error records.
ca01d6dd	253	*/
6dda9266	254	void pstore_get_records(int quiet)
ca01d6dd TL	255	{
ca01d6dd TL	256	struct pstore_info *psi = psinfo;
f6f82851	257	char *buf = NULL;
8d38d74b	258	ssize_t size;
ca01d6dd TL	259	u64 id;
	260	enum pstore_type_id type;
	261	struct timespec time;
06cf91b4	262	int failed = 0, rc;
ca01d6dd TL	263
	264	if (!psi)
	265	return;
	266
f6f82851	267	mutex_lock(&psi->read_mutex);
2174f6df	268	if (psi->open && psi->open(psi))
06cf91b4 CG	269	goto out;
06cf91b4 CG	270
f6f82851 KC	271	while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
f6f82851 KC	272	rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
6dda9266	273	time, psi);
f6f82851 KC	274	kfree(buf);
f6f82851 KC	275	buf = NULL;
6dda9266	276	if (rc && (rc != -EEXIST \|\| !quiet))
ca01d6dd TL	277	failed++;
ca01d6dd TL	278	}
2174f6df KC	279	if (psi->close)
2174f6df KC	280	psi->close(psi);
06cf91b4	281	out:
f6f82851	282	mutex_unlock(&psi->read_mutex);
ca01d6dd TL	283
	284	if (failed)
	285	printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
	286	failed, psi->name);
	287	}
	288
6dda9266 TL	289	static void pstore_dowork(struct work_struct *work)
	290	{
	291	pstore_get_records(1);
	292	}
	293
	294	static void pstore_timefunc(unsigned long dummy)
	295	{
	296	if (pstore_new_entry) {
	297	pstore_new_entry = 0;
	298	schedule_work(&pstore_work);
	299	}
	300
a3f5f075	301	mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
6dda9266 TL	302	}
6dda9266 TL	303
dee28e72 MG	304	module_param(backend, charp, 0444);
dee28e72 MG	305	MODULE_PARM_DESC(backend, "Pstore backend to use");