[mirror_ubuntu-bionic-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 = -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";
	}
}

/*
 * 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 (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) {
		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 + len, psinfo);
		if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
			pstore_new_entry = 1;

		total += hsize + len;
		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;
		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, 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 size, struct pstore_info *psi)
{
	return psi->write_buf(type, reason, id, part, psinfo->buf, 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 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	*/
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 TL	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
ca01d6dd TL	99	/*
	100	* callback from kmsg_dump. (s2,l2) has the most recently
	101	* written bytes, older bytes are in (s1,l1). Save as much
	102	* as we can from the end of the buffer.
	103	*/
	104	static void pstore_dump(struct kmsg_dumper *dumper,
e2ae715d	105	enum kmsg_dump_reason reason)
ca01d6dd	106	{
e2ae715d	107	unsigned long total = 0;
381b872c	108	const char *why;
ca01d6dd	109	u64 id;
b94fdd07	110	unsigned int part = 1;
abd4d558 DZ	111	unsigned long flags = 0;
abd4d558 DZ	112	int is_locked = 0;
e2ae715d	113	int ret;
ca01d6dd	114
381b872c	115	why = get_reason_str(reason);
9f6af27f	116
abd4d558 DZ	117	if (in_nmi()) {
	118	is_locked = spin_trylock(&psinfo->buf_lock);
	119	if (!is_locked)
	120	pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
	121	} else
	122	spin_lock_irqsave(&psinfo->buf_lock, flags);
ca01d6dd TL	123	oopscount++;
ca01d6dd TL	124	while (total < kmsg_bytes) {
e2ae715d KS	125	char *dst;
	126	unsigned long size;
	127	int hsize;
	128	size_t len;
	129
ca01d6dd	130	dst = psinfo->buf;
56280682	131	hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
ca01d6dd TL	132	size = psinfo->bufsize - hsize;
	133	dst += hsize;
	134
e2ae715d	135	if (!kmsg_dump_get_buffer(dumper, true, dst, size, &len))
ca01d6dd TL	136	break;
ca01d6dd TL	137
3d6d8d20	138	ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
755d4fe4	139	oopscount, hsize + len, psinfo);
b238b8fa	140	if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
6dda9266	141	pstore_new_entry = 1;
e2ae715d KS	142
e2ae715d KS	143	total += hsize + len;
56280682	144	part++;
ca01d6dd	145	}
abd4d558 DZ	146	if (in_nmi()) {
	147	if (is_locked)
	148	spin_unlock(&psinfo->buf_lock);
	149	} else
	150	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
ca01d6dd TL	151	}
	152
	153	static struct kmsg_dumper pstore_dumper = {
	154	.dump = pstore_dump,
	155	};
	156
f29e5956 AV	157	#ifdef CONFIG_PSTORE_CONSOLE
	158	static void pstore_console_write(struct console con, const char s, unsigned c)
	159	{
	160	const char *e = s + c;
	161
	162	while (s < e) {
	163	unsigned long flags;
70a6f46d	164	u64 id;
f29e5956 AV	165
	166	if (c > psinfo->bufsize)
	167	c = psinfo->bufsize;
80c9d03c CL	168
	169	if (oops_in_progress) {
	170	if (!spin_trylock_irqsave(&psinfo->buf_lock, flags))
	171	break;
	172	} else {
	173	spin_lock_irqsave(&psinfo->buf_lock, flags);
	174	}
f29e5956	175	memcpy(psinfo->buf, s, c);
755d4fe4	176	psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, c, psinfo);
f29e5956 AV	177	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
	178	s += c;
	179	c = e - s;
	180	}
	181	}
	182
	183	static struct console pstore_console = {
	184	.name = "pstore",
	185	.write = pstore_console_write,
	186	.flags = CON_PRINTBUFFER \| CON_ENABLED \| CON_ANYTIME,
	187	.index = -1,
	188	};
	189
	190	static void pstore_register_console(void)
	191	{
	192	register_console(&pstore_console);
	193	}
	194	#else
	195	static void pstore_register_console(void) {}
	196	#endif
	197
897dba02 AV	198	static int pstore_write_compat(enum pstore_type_id type,
897dba02 AV	199	enum kmsg_dump_reason reason,
755d4fe4	200	u64 *id, unsigned int part, int count,
897dba02 AV	201	size_t size, struct pstore_info *psi)
	202	{
	203	return psi->write_buf(type, reason, id, part, psinfo->buf, size, psi);
	204	}
	205
ca01d6dd TL	206	/*
	207	* platform specific persistent storage driver registers with
	208	* us here. If pstore is already mounted, call the platform
	209	* read function right away to populate the file system. If not
	210	* then the pstore mount code will call us later to fill out
	211	* the file system.
	212	*
	213	* Register with kmsg_dump to save last part of console log on panic.
	214	*/
	215	int pstore_register(struct pstore_info *psi)
	216	{
	217	struct module *owner = psi->owner;
	218
	219	spin_lock(&pstore_lock);
	220	if (psinfo) {
	221	spin_unlock(&pstore_lock);
	222	return -EBUSY;
	223	}
dee28e72 MG	224
	225	if (backend && strcmp(backend, psi->name)) {
	226	spin_unlock(&pstore_lock);
	227	return -EINVAL;
	228	}
	229
897dba02 AV	230	if (!psi->write)
897dba02 AV	231	psi->write = pstore_write_compat;
ca01d6dd	232	psinfo = psi;
f6f82851	233	mutex_init(&psinfo->read_mutex);
ca01d6dd TL	234	spin_unlock(&pstore_lock);
	235
	236	if (owner && !try_module_get(owner)) {
	237	psinfo = NULL;
	238	return -EINVAL;
	239	}
	240
	241	if (pstore_is_mounted())
6dda9266	242	pstore_get_records(0);
ca01d6dd TL	243
ca01d6dd TL	244	kmsg_dump_register(&pstore_dumper);
f29e5956	245	pstore_register_console();
65f8c95e	246	pstore_register_ftrace();
ca01d6dd	247
a3f5f075 AV	248	if (pstore_update_ms >= 0) {
	249	pstore_timer.expires = jiffies +
	250	msecs_to_jiffies(pstore_update_ms);
	251	add_timer(&pstore_timer);
	252	}
6dda9266	253
ca01d6dd TL	254	return 0;
	255	}
	256	EXPORT_SYMBOL_GPL(pstore_register);
	257
	258	/*
6dda9266 TL	259	* Read all the records from the persistent store. Create
	260	* files in our filesystem. Don't warn about -EEXIST errors
	261	* when we are re-scanning the backing store looking to add new
	262	* error records.
ca01d6dd	263	*/
6dda9266	264	void pstore_get_records(int quiet)
ca01d6dd TL	265	{
ca01d6dd TL	266	struct pstore_info *psi = psinfo;
f6f82851	267	char *buf = NULL;
8d38d74b	268	ssize_t size;
ca01d6dd	269	u64 id;
755d4fe4	270	int count;
ca01d6dd TL	271	enum pstore_type_id type;
ca01d6dd TL	272	struct timespec time;
06cf91b4	273	int failed = 0, rc;
ca01d6dd TL	274
	275	if (!psi)
	276	return;
	277
f6f82851	278	mutex_lock(&psi->read_mutex);
2174f6df	279	if (psi->open && psi->open(psi))
06cf91b4 CG	280	goto out;
06cf91b4 CG	281
755d4fe4 SA	282	while ((size = psi->read(&id, &type, &count, &time, &buf, psi)) > 0) {
	283	rc = pstore_mkfile(type, psi->name, id, count, buf,
	284	(size_t)size, time, psi);
f6f82851 KC	285	kfree(buf);
f6f82851 KC	286	buf = NULL;
6dda9266	287	if (rc && (rc != -EEXIST \|\| !quiet))
ca01d6dd TL	288	failed++;
ca01d6dd TL	289	}
2174f6df KC	290	if (psi->close)
2174f6df KC	291	psi->close(psi);
06cf91b4	292	out:
f6f82851	293	mutex_unlock(&psi->read_mutex);
ca01d6dd TL	294
	295	if (failed)
	296	printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
	297	failed, psi->name);
	298	}
	299
6dda9266 TL	300	static void pstore_dowork(struct work_struct *work)
	301	{
	302	pstore_get_records(1);
	303	}
	304
	305	static void pstore_timefunc(unsigned long dummy)
	306	{
	307	if (pstore_new_entry) {
	308	pstore_new_entry = 0;
	309	schedule_work(&pstore_work);
	310	}
	311
a3f5f075	312	mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms));
6dda9266 TL	313	}
6dda9266 TL	314
dee28e72 MG	315	module_param(backend, charp, 0444);
dee28e72 MG	316	MODULE_PARM_DESC(backend, "Pstore backend to use");