[deliverable/linux.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 = -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";
	}
}

bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
{
	/*
	 * In case of NMI path, pstore shouldn't be blocked
	 * regardless of reason.
	 */
	if (in_nmi())
		return true;

	switch (reason) {
	/* In panic case, other cpus are stopped by smp_send_stop(). */
	case KMSG_DUMP_PANIC:
	/* Emergency restart shouldn't be blocked by spin lock. */
	case KMSG_DUMP_EMERG:
		return true;
	default:
		return false;
	}
}
EXPORT_SYMBOL_GPL(pstore_cannot_block_path);

/*
 * 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 (pstore_cannot_block_path(reason)) {
		is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
		if (!is_locked) {
			pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
				       , in_nmi() ? "NMI" : why);
		}
	} 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,
				    oopscount, hsize, hsize + len, psinfo);
		if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
			pstore_new_entry = 1;

		total += hsize + len;
		part++;
	}
	if (pstore_cannot_block_path(reason)) {
		if (is_locked)
			spin_unlock_irqrestore(&psinfo->buf_lock, flags);
	} 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;
		u64 id;

		if (c > psinfo->bufsize)
			c = psinfo->bufsize;

		if (oops_in_progress) {
			if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
				break;
		} else {
			spin_lock_irqsave(&psinfo->buf_lock, flags);
		}
		memcpy(psinfo->buf, s, c);
		psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 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, int count,
			       size_t hsize, size_t size,
			       struct pstore_info *psi)
{
	return psi->write_buf(type, reason, id, part, psinfo->buf, hsize,
			     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();
	pstore_register_ftrace();

	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;
	int			count;
	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, &count, &time, &buf, psi)) > 0) {
		rc = pstore_mkfile(type, psi->name, id, count, 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 LT	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	*/
521f7288	44	static int pstore_update_ms = -1;
a3f5f075 AV	45	module_param_named(update_ms, pstore_update_ms, int, 0600);
a3f5f075 AV	46	MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
521f7288 AV	47	"(default is -1, which means runtime updates are disabled; "
	48	"enabling this option is not safe, it may lead to further "
	49	"corruption on Oopses)");
6dda9266 LT	50
	51	static int pstore_new_entry;
	52
	53	static void pstore_timefunc(unsigned long);
	54	static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
	55
	56	static void pstore_dowork(struct work_struct *);
	57	static DECLARE_WORK(pstore_work, pstore_dowork);
	58
ca01d6dd TL	59	/*
	60	* pstore_lock just protects "psinfo" during
	61	* calls to pstore_register()
	62	*/
	63	static DEFINE_SPINLOCK(pstore_lock);
060287b8	64	struct pstore_info *psinfo;
ca01d6dd	65
dee28e72 MG	66	static char *backend;
dee28e72 MG	67
366f7e7a	68	/* How much of the console log to snapshot */
ca01d6dd TL	69	static unsigned long kmsg_bytes = 10240;
ca01d6dd TL	70
366f7e7a	71	void pstore_set_kmsg_bytes(int bytes)
ca01d6dd	72	{
366f7e7a	73	kmsg_bytes = bytes;
ca01d6dd TL	74	}
ca01d6dd TL	75
ca01d6dd TL	76	/* Tag each group of saved records with a sequence number */
	77	static int oopscount;
	78
381b872c SA	79	static const char *get_reason_str(enum kmsg_dump_reason reason)
	80	{
	81	switch (reason) {
	82	case KMSG_DUMP_PANIC:
	83	return "Panic";
	84	case KMSG_DUMP_OOPS:
	85	return "Oops";
	86	case KMSG_DUMP_EMERG:
	87	return "Emergency";
	88	case KMSG_DUMP_RESTART:
	89	return "Restart";
	90	case KMSG_DUMP_HALT:
	91	return "Halt";
	92	case KMSG_DUMP_POWEROFF:
	93	return "Poweroff";
	94	default:
	95	return "Unknown";
	96	}
	97	}
9f6af27f	98
9f244e9c SA	99	bool pstore_cannot_block_path(enum kmsg_dump_reason reason)
	100	{
	101	/*
	102	* In case of NMI path, pstore shouldn't be blocked
	103	* regardless of reason.
	104	*/
	105	if (in_nmi())
	106	return true;
	107
	108	switch (reason) {
	109	/* In panic case, other cpus are stopped by smp_send_stop(). */
	110	case KMSG_DUMP_PANIC:
	111	/* Emergency restart shouldn't be blocked by spin lock. */
	112	case KMSG_DUMP_EMERG:
	113	return true;
	114	default:
	115	return false;
	116	}
	117	}
	118	EXPORT_SYMBOL_GPL(pstore_cannot_block_path);
	119
ca01d6dd TL	120	/*
	121	* callback from kmsg_dump. (s2,l2) has the most recently
	122	* written bytes, older bytes are in (s1,l1). Save as much
	123	* as we can from the end of the buffer.
	124	*/
	125	static void pstore_dump(struct kmsg_dumper *dumper,
e2ae715d	126	enum kmsg_dump_reason reason)
ca01d6dd	127	{
e2ae715d	128	unsigned long total = 0;
381b872c	129	const char *why;
ca01d6dd	130	u64 id;
b94fdd07	131	unsigned int part = 1;
abd4d558 DZ	132	unsigned long flags = 0;
abd4d558 DZ	133	int is_locked = 0;
e2ae715d	134	int ret;
ca01d6dd	135
381b872c	136	why = get_reason_str(reason);
9f6af27f	137
9f244e9c SA	138	if (pstore_cannot_block_path(reason)) {
	139	is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags);
	140	if (!is_locked) {
	141	pr_err("pstore dump routine blocked in %s path, may corrupt error record\n"
	142	, in_nmi() ? "NMI" : why);
	143	}
abd4d558 DZ	144	} else
abd4d558 DZ	145	spin_lock_irqsave(&psinfo->buf_lock, flags);
ca01d6dd TL	146	oopscount++;
ca01d6dd TL	147	while (total < kmsg_bytes) {
e2ae715d KS	148	char *dst;
	149	unsigned long size;
	150	int hsize;
	151	size_t len;
	152
ca01d6dd	153	dst = psinfo->buf;
56280682	154	hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
ca01d6dd TL	155	size = psinfo->bufsize - hsize;
	156	dst += hsize;
	157
e2ae715d	158	if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
ca01d6dd TL	159	break;
ca01d6dd TL	160
3d6d8d20	161	ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
6bbbca73	162	oopscount, hsize, hsize + len, psinfo);
b238b8fa	163	if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
6dda9266	164	pstore_new_entry = 1;
e2ae715d KS	165
e2ae715d KS	166	total += hsize + len;
56280682	167	part++;
ca01d6dd	168	}
9f244e9c	169	if (pstore_cannot_block_path(reason)) {
abd4d558	170	if (is_locked)
9f244e9c	171	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
abd4d558 DZ	172	} else
abd4d558 DZ	173	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
ca01d6dd TL	174	}
	175
	176	static struct kmsg_dumper pstore_dumper = {
	177	.dump = pstore_dump,
	178	};
	179
f29e5956 AV	180	#ifdef CONFIG_PSTORE_CONSOLE
	181	static void pstore_console_write(struct console con, const char s, unsigned c)
	182	{
	183	const char *e = s + c;
	184
	185	while (s < e) {
	186	unsigned long flags;
70a6f46d	187	u64 id;
f29e5956 AV	188
	189	if (c > psinfo->bufsize)
	190	c = psinfo->bufsize;
80c9d03c CL	191
	192	if (oops_in_progress) {
	193	if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
	194	break;
	195	} else {
	196	spin_lock_irqsave(&psinfo->buf_lock, flags);
	197	}
f29e5956	198	memcpy(psinfo->buf, s, c);
6bbbca73	199	psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, 0, c, psinfo);
f29e5956 AV	200	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
	201	s += c;
	202	c = e - s;
	203	}
	204	}
	205
	206	static struct console pstore_console = {
	207	.name = "pstore",
	208	.write = pstore_console_write,
	209	.flags = CON_PRINTBUFFER \| CON_ENABLED \| CON_ANYTIME,
	210	.index = -1,
	211	};
	212
	213	static void pstore_register_console(void)
	214	{
	215	register_console(&pstore_console);
	216	}
	217	#else
	218	static void pstore_register_console(void) {}
	219	#endif
	220
897dba02 AV	221	static int pstore_write_compat(enum pstore_type_id type,
897dba02 AV	222	enum kmsg_dump_reason reason,
755d4fe4	223	u64 *id, unsigned int part, int count,
6bbbca73 AB	224	size_t hsize, size_t size,
6bbbca73 AB	225	struct pstore_info *psi)
897dba02	226	{
6bbbca73 AB	227	return psi->write_buf(type, reason, id, part, psinfo->buf, hsize,
6bbbca73 AB	228	size, psi);
897dba02 AV	229	}
897dba02 AV	230
ca01d6dd TL	231	/*
	232	* platform specific persistent storage driver registers with
	233	* us here. If pstore is already mounted, call the platform
	234	* read function right away to populate the file system. If not
	235	* then the pstore mount code will call us later to fill out
	236	* the file system.
	237	*
	238	* Register with kmsg_dump to save last part of console log on panic.
	239	*/
	240	int pstore_register(struct pstore_info *psi)
	241	{
	242	struct module *owner = psi->owner;
	243
	244	spin_lock(&pstore_lock);
	245	if (psinfo) {
	246	spin_unlock(&pstore_lock);
	247	return -EBUSY;
	248	}
dee28e72 MG	249
	250	if (backend && strcmp(backend, psi->name)) {
	251	spin_unlock(&pstore_lock);
	252	return -EINVAL;
	253	}
	254
897dba02 AV	255	if (!psi->write)
897dba02 AV	256	psi->write = pstore_write_compat;
ca01d6dd	257	psinfo = psi;
f6f82851	258	mutex_init(&psinfo->read_mutex);
ca01d6dd TL	259	spin_unlock(&pstore_lock);
	260
	261	if (owner && !try_module_get(owner)) {
	262	psinfo = NULL;
	263	return -EINVAL;
	264	}
	265
	266	if (pstore_is_mounted())
6dda9266	267	pstore_get_records(0);
ca01d6dd TL	268
ca01d6dd TL	269	kmsg_dump_register(&pstore_dumper);
f29e5956	270	pstore_register_console();
65f8c95e	271	pstore_register_ftrace();
ca01d6dd	272
a3f5f075 AV	273	if (pstore_update_ms >= 0) {
	274	pstore_timer.expires = jiffies +
	275	msecs_to_jiffies(pstore_update_ms);
	276	add_timer(&pstore_timer);
	277	}
6dda9266	278
ca01d6dd TL	279	return 0;
	280	}
	281	EXPORT_SYMBOL_GPL(pstore_register);
	282
	283	/*
6dda9266 LT	284	* Read all the records from the persistent store. Create
	285	* files in our filesystem. Don't warn about -EEXIST errors
	286	* when we are re-scanning the backing store looking to add new
	287	* error records.
ca01d6dd	288	*/
6dda9266	289	void pstore_get_records(int quiet)
ca01d6dd TL	290	{
ca01d6dd TL	291	struct pstore_info *psi = psinfo;
f6f82851	292	char *buf = NULL;
8d38d74b	293	ssize_t size;
ca01d6dd	294	u64 id;
755d4fe4	295	int count;
ca01d6dd TL	296	enum pstore_type_id type;
ca01d6dd TL	297	struct timespec time;
06cf91b4	298	int failed = 0, rc;
ca01d6dd TL	299
	300	if (!psi)
	301	return;
	302
f6f82851	303	mutex_lock(&psi->read_mutex);
2174f6df	304	if (psi->open && psi->open(psi))
06cf91b4 CG	305	goto out;
06cf91b4 CG	306
755d4fe4 SA	307	while ((size = psi->read(&id, &type, &count, &time, &buf, psi)) > 0) {
	308	rc = pstore_mkfile(type, psi->name, id, count, buf,
	309	(size_t)size, time, psi);
f6f82851 KC	310	kfree(buf);
f6f82851 KC	311	buf = NULL;
6dda9266	312	if (rc && (rc != -EEXIST \|\| !quiet))
ca01d6dd TL	313	failed++;
ca01d6dd TL	314	}
2174f6df KC	315	if (psi->close)
2174f6df KC	316	psi->close(psi);
06cf91b4	317	out:
f6f82851	318	mutex_unlock(&psi->read_mutex);
ca01d6dd TL	319
	320	if (failed)
	321	printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
	322	failed, psi->name);
	323	}
	324
6dda9266 LT	325	static void pstore_dowork(struct work_struct *work)
	326	{
	327	pstore_get_records(1);
	328	}
	329
	330	static void pstore_timefunc(unsigned long dummy)
	331	{
	332	if (pstore_new_entry) {
	333	pstore_new_entry = 0;
	334	schedule_work(&pstore_work);
	335	}
	336
a3f5f075	337	mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
6dda9266 LT	338	}
6dda9266 LT	339
dee28e72 MG	340	module_param(backend, charp, 0444);
dee28e72 MG	341	MODULE_PARM_DESC(backend, "Pstore backend to use");