[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/timer.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/hardirq.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
 */
#define	PSTORE_INTERVAL	(60 * HZ)

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 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;
	unsigned long	flags = 0;
	int		is_locked = 0;

	if (reason < ARRAY_SIZE(reason_str))
		why = reason_str[reason];
	else
		why = "Unknown";

	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);

		id = psinfo->write(PSTORE_TYPE_DMESG, part,
				   hsize + l1_cpy + l2_cpy, psinfo);
		if (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,
};

/*
 * 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(0);

	kmsg_dump_register(&pstore_dumper);

	pstore_timer.expires = jiffies + PSTORE_INTERVAL;
	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;
	ssize_t			size;
	u64			id;
	enum pstore_type_id	type;
	struct timespec		time;
	int			failed = 0, rc;
	unsigned long		flags;

	if (!psi)
		return;

	spin_lock_irqsave(&psinfo->buf_lock, flags);
	rc = psi->open(psi);
	if (rc)
		goto out;

	while ((size = psi->read(&id, &type, &time, psi)) > 0) {
		rc = pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
				  time, psi);
		if (rc && (rc != -EEXIST || !quiet))
			failed++;
	}
	psi->close(psi);
out:
	spin_unlock_irqrestore(&psinfo->buf_lock, flags);

	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 + PSTORE_INTERVAL);
}

/*
 * 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;
	unsigned long	flags;

	if (!psinfo)
		return -ENODEV;

	if (size > psinfo->bufsize)
		return -EFBIG;

	spin_lock_irqsave(&psinfo->buf_lock, flags);
	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);
	spin_unlock_irqrestore(&psinfo->buf_lock, flags);

	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>
6dda9266	28	#include <linux/timer.h>
ca01d6dd TL	29	#include <linux/slab.h>
ca01d6dd TL	30	#include <linux/uaccess.h>
abd4d558	31	#include <linux/hardirq.h>
6dda9266	32	#include <linux/workqueue.h>
ca01d6dd TL	33
	34	#include "internal.h"
	35
6dda9266 TL	36	/*
	37	* We defer making "oops" entries appear in pstore - see
	38	* whether the system is actually still running well enough
	39	* to let someone see the entry
	40	*/
	41	#define PSTORE_INTERVAL (60 * HZ)
	42
	43	static int pstore_new_entry;
	44
	45	static void pstore_timefunc(unsigned long);
	46	static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0);
	47
	48	static void pstore_dowork(struct work_struct *);
	49	static DECLARE_WORK(pstore_work, pstore_dowork);
	50
ca01d6dd TL	51	/*
	52	* pstore_lock just protects "psinfo" during
	53	* calls to pstore_register()
	54	*/
	55	static DEFINE_SPINLOCK(pstore_lock);
	56	static struct pstore_info *psinfo;
	57
dee28e72 MG	58	static char *backend;
dee28e72 MG	59
366f7e7a	60	/* How much of the console log to snapshot */
ca01d6dd TL	61	static unsigned long kmsg_bytes = 10240;
ca01d6dd TL	62
366f7e7a	63	void pstore_set_kmsg_bytes(int bytes)
ca01d6dd	64	{
366f7e7a	65	kmsg_bytes = bytes;
ca01d6dd TL	66	}
ca01d6dd TL	67
ca01d6dd TL	68	/* Tag each group of saved records with a sequence number */
	69	static int oopscount;
	70
9f6af27f TL	71	static char *reason_str[] = {
	72	"Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency"
	73	};
	74
ca01d6dd TL	75	/*
	76	* callback from kmsg_dump. (s2,l2) has the most recently
	77	* written bytes, older bytes are in (s1,l1). Save as much
	78	* as we can from the end of the buffer.
	79	*/
	80	static void pstore_dump(struct kmsg_dumper *dumper,
	81	enum kmsg_dump_reason reason,
	82	const char *s1, unsigned long l1,
	83	const char *s2, unsigned long l2)
	84	{
	85	unsigned long s1_start, s2_start;
	86	unsigned long l1_cpy, l2_cpy;
	87	unsigned long size, total = 0;
9f6af27f	88	char dst, why;
ca01d6dd	89	u64 id;
b94fdd07 MG	90	int hsize;
b94fdd07 MG	91	unsigned int part = 1;
abd4d558 DZ	92	unsigned long flags = 0;
abd4d558 DZ	93	int is_locked = 0;
ca01d6dd	94
9f6af27f TL	95	if (reason < ARRAY_SIZE(reason_str))
	96	why = reason_str[reason];
	97	else
	98	why = "Unknown";
	99
abd4d558 DZ	100	if (in_nmi()) {
	101	is_locked = spin_trylock(&psinfo->buf_lock);
	102	if (!is_locked)
	103	pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
	104	} else
	105	spin_lock_irqsave(&psinfo->buf_lock, flags);
ca01d6dd TL	106	oopscount++;
	107	while (total < kmsg_bytes) {
	108	dst = psinfo->buf;
56280682	109	hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part);
ca01d6dd TL	110	size = psinfo->bufsize - hsize;
	111	dst += hsize;
	112
	113	l2_cpy = min(l2, size);
	114	l1_cpy = min(l1, size - l2_cpy);
	115
	116	if (l1_cpy + l2_cpy == 0)
	117	break;
	118
	119	s2_start = l2 - l2_cpy;
	120	s1_start = l1 - l1_cpy;
	121
	122	memcpy(dst, s1 + s1_start, l1_cpy);
	123	memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy);
	124
56280682 MG	125	id = psinfo->write(PSTORE_TYPE_DMESG, part,
56280682 MG	126	hsize + l1_cpy + l2_cpy, psinfo);
9f6af27f	127	if (reason == KMSG_DUMP_OOPS && pstore_is_mounted())
6dda9266	128	pstore_new_entry = 1;
ca01d6dd TL	129	l1 -= l1_cpy;
	130	l2 -= l2_cpy;
	131	total += l1_cpy + l2_cpy;
56280682	132	part++;
ca01d6dd	133	}
abd4d558 DZ	134	if (in_nmi()) {
	135	if (is_locked)
	136	spin_unlock(&psinfo->buf_lock);
	137	} else
	138	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
ca01d6dd TL	139	}
	140
	141	static struct kmsg_dumper pstore_dumper = {
	142	.dump = pstore_dump,
	143	};
	144
	145	/*
	146	* platform specific persistent storage driver registers with
	147	* us here. If pstore is already mounted, call the platform
	148	* read function right away to populate the file system. If not
	149	* then the pstore mount code will call us later to fill out
	150	* the file system.
	151	*
	152	* Register with kmsg_dump to save last part of console log on panic.
	153	*/
	154	int pstore_register(struct pstore_info *psi)
	155	{
	156	struct module *owner = psi->owner;
	157
	158	spin_lock(&pstore_lock);
	159	if (psinfo) {
	160	spin_unlock(&pstore_lock);
	161	return -EBUSY;
	162	}
dee28e72 MG	163
	164	if (backend && strcmp(backend, psi->name)) {
	165	spin_unlock(&pstore_lock);
	166	return -EINVAL;
	167	}
	168
ca01d6dd TL	169	psinfo = psi;
	170	spin_unlock(&pstore_lock);
	171
	172	if (owner && !try_module_get(owner)) {
	173	psinfo = NULL;
	174	return -EINVAL;
	175	}
	176
	177	if (pstore_is_mounted())
6dda9266	178	pstore_get_records(0);
ca01d6dd TL	179
	180	kmsg_dump_register(&pstore_dumper);
	181
6dda9266 TL	182	pstore_timer.expires = jiffies + PSTORE_INTERVAL;
	183	add_timer(&pstore_timer);
	184
ca01d6dd TL	185	return 0;
	186	}
	187	EXPORT_SYMBOL_GPL(pstore_register);
	188
	189	/*
6dda9266 TL	190	* Read all the records from the persistent store. Create
	191	* files in our filesystem. Don't warn about -EEXIST errors
	192	* when we are re-scanning the backing store looking to add new
	193	* error records.
ca01d6dd	194	*/
6dda9266	195	void pstore_get_records(int quiet)
ca01d6dd TL	196	{
ca01d6dd TL	197	struct pstore_info *psi = psinfo;
8d38d74b	198	ssize_t size;
ca01d6dd TL	199	u64 id;
	200	enum pstore_type_id type;
	201	struct timespec time;
06cf91b4	202	int failed = 0, rc;
abd4d558	203	unsigned long flags;
ca01d6dd TL	204
	205	if (!psi)
	206	return;
	207
abd4d558	208	spin_lock_irqsave(&psinfo->buf_lock, flags);
06cf91b4 CG	209	rc = psi->open(psi);
	210	if (rc)
	211	goto out;
	212
638c1fd3	213	while ((size = psi->read(&id, &type, &time, psi)) > 0) {
6dda9266 TL	214	rc = pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
	215	time, psi);
	216	if (rc && (rc != -EEXIST \|\| !quiet))
ca01d6dd TL	217	failed++;
ca01d6dd TL	218	}
06cf91b4 CG	219	psi->close(psi);
06cf91b4 CG	220	out:
abd4d558	221	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
ca01d6dd TL	222
	223	if (failed)
	224	printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n",
	225	failed, psi->name);
	226	}
	227
6dda9266 TL	228	static void pstore_dowork(struct work_struct *work)
	229	{
	230	pstore_get_records(1);
	231	}
	232
	233	static void pstore_timefunc(unsigned long dummy)
	234	{
	235	if (pstore_new_entry) {
	236	pstore_new_entry = 0;
	237	schedule_work(&pstore_work);
	238	}
	239
	240	mod_timer(&pstore_timer, jiffies + PSTORE_INTERVAL);
	241	}
	242
ca01d6dd TL	243	/*
	244	* Call platform driver to write a record to the
	245	* persistent store.
	246	*/
	247	int pstore_write(enum pstore_type_id type, char *buf, size_t size)
	248	{
abd4d558 DZ	249	u64 id;
abd4d558 DZ	250	unsigned long flags;
ca01d6dd TL	251
	252	if (!psinfo)
	253	return -ENODEV;
	254
	255	if (size > psinfo->bufsize)
	256	return -EFBIG;
	257
abd4d558	258	spin_lock_irqsave(&psinfo->buf_lock, flags);
ca01d6dd	259	memcpy(psinfo->buf, buf, size);
56280682	260	id = psinfo->write(type, 0, size, psinfo);
ca01d6dd TL	261	if (pstore_is_mounted())
ca01d6dd TL	262	pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf,
638c1fd3	263	size, CURRENT_TIME, psinfo);
abd4d558	264	spin_unlock_irqrestore(&psinfo->buf_lock, flags);
ca01d6dd TL	265
	266	return 0;
	267	}
	268	EXPORT_SYMBOL_GPL(pstore_write);
dee28e72 MG	269
	270	module_param(backend, charp, 0444);
	271	MODULE_PARM_DESC(backend, "Pstore backend to use");