[mirror_ubuntu-bionic-kernel.git] / include / linux / pstore.h

/*
 * Persistent Storage - pstore.h
 *
 * Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
 *
 * This code is the generic layer to export data records from platform
 * level persistent storage via a file system.
 *
 *  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
 */
#ifndef _LINUX_PSTORE_H
#define _LINUX_PSTORE_H

#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/kmsg_dump.h>
#include <linux/mutex.h>
#include <linux/semaphore.h>
#include <linux/time.h>
#include <linux/types.h>

struct module;

/* pstore record types (see fs/pstore/inode.c for filename templates) */
enum pstore_type_id {
	PSTORE_TYPE_DMESG	= 0,
	PSTORE_TYPE_MCE		= 1,
	PSTORE_TYPE_CONSOLE	= 2,
	PSTORE_TYPE_FTRACE	= 3,
	/* PPC64 partition types */
	PSTORE_TYPE_PPC_RTAS	= 4,
	PSTORE_TYPE_PPC_OF	= 5,
	PSTORE_TYPE_PPC_COMMON	= 6,
	PSTORE_TYPE_PMSG	= 7,
	PSTORE_TYPE_PPC_OPAL	= 8,
	PSTORE_TYPE_UNKNOWN	= 255
};

struct pstore_info;
/**
 * struct pstore_record - details of a pstore record entry
 * @psi:	pstore backend driver information
 * @type:	pstore record type
 * @id:		per-type unique identifier for record
 * @time:	timestamp of the record
 * @buf:	pointer to record contents
 * @size:	size of @buf
 * @ecc_notice_size:
 *		ECC information for @buf
 *
 * Valid for PSTORE_TYPE_DMESG @type:
 *
 * @count:	Oops count since boot
 * @reason:	kdump reason for notification
 * @part:	position in a multipart record
 * @compressed:	whether the buffer is compressed
 *
 */
struct pstore_record {
	struct pstore_info	*psi;
	enum pstore_type_id	type;
	u64			id;
	struct timespec		time;
	char			*buf;
	ssize_t			size;
	ssize_t			ecc_notice_size;

	int			count;
	enum kmsg_dump_reason	reason;
	unsigned int		part;
	bool			compressed;
};

/**
 * struct pstore_info - backend pstore driver structure
 *
 * @owner:	module which is repsonsible for this backend driver
 * @name:	name of the backend driver
 *
 * @buf_lock:	semaphore to serialize access to @buf
 * @buf:	preallocated crash dump buffer
 * @bufsize:	size of @buf available for crash dump bytes (must match
 *		smallest number of bytes available for writing to a
 *		backend entry, since compressed bytes don't take kindly
 *		to being truncated)
 *
 * @read_mutex:	serializes @open, @read, @close, and @erase callbacks
 * @flags:	bitfield of frontends the backend can accept writes for
 * @data:	backend-private pointer passed back during callbacks
 *
 * Callbacks:
 *
 * @open:
 *	Notify backend that pstore is starting a full read of backend
 *	records. Followed by one or more @read calls, and a final @close.
 *
 *	@psi:	in: pointer to the struct pstore_info for the backend
 *
 *	Returns 0 on success, and non-zero on error.
 *
 * @close:
 *	Notify backend that pstore has finished a full read of backend
 *	records. Always preceded by an @open call and one or more @read
 *	calls.
 *
 *	@psi:	in: pointer to the struct pstore_info for the backend
 *
 *	Returns 0 on success, and non-zero on error. (Though pstore will
 *	ignore the error.)
 *
 * @read:
 *	Read next available backend record. Called after a successful
 *	@open.
 *
 *	@record:
 *		pointer to record to populate. @buf should be allocated
 *		by the backend and filled. At least @type and @id should
 *		be populated, since these are used when creating pstorefs
 *		file names.
 *
 *	Returns record size on success, zero when no more records are
 *	available, or negative on error.
 *
 * @write:
 *	A newly generated record needs to be written to backend storage.
 *
 *	@record:
 *		pointer to record metadata. When @type is PSTORE_TYPE_DMESG,
 *		@buf will be pointing to the preallocated @psi.buf, since
 *		memory allocation may be broken during an Oops. Regardless,
 *		@buf must be proccesed or copied before returning. The
 *		backend is also expected to write @id with something that
 *		can help identify this record to a future @erase callback.
 *		The @time field will be prepopulated with the current time,
 *		when available. The @size field will have the size of data
 *		in @buf.
 *
 *	Returns 0 on success, and non-zero on error.
 *
 * @write_user:
 *	Perform a frontend write to a backend record, using a specified
 *	buffer that is coming directly from userspace, instead of the
 *	@record @buf.
 *
 *	@record:	pointer to record metadata.
 *	@buf:		pointer to userspace contents to write to backend
 *
 *	Returns 0 on success, and non-zero on error.
 *
 * @erase:
 *	Delete a record from backend storage.  Different backends
 *	identify records differently, so entire original record is
 *	passed back to assist in identification of what the backend
 *	should remove from storage.
 *
 *	@record:	pointer to record metadata.
 *
 *	Returns 0 on success, and non-zero on error.
 *
 */
struct pstore_info {
	struct module	*owner;
	char		*name;

	struct semaphore buf_lock;
	char		*buf;
	size_t		bufsize;

	struct mutex	read_mutex;

	int		flags;
	void		*data;

	int		(*open)(struct pstore_info *psi);
	int		(*close)(struct pstore_info *psi);
	ssize_t		(*read)(struct pstore_record *record);
	int		(*write)(struct pstore_record *record);
	int		(*write_user)(struct pstore_record *record,
				      const char __user *buf);
	int		(*erase)(struct pstore_record *record);
};

/* Supported frontends */
#define PSTORE_FLAGS_DMESG	(1 << 0)
#define PSTORE_FLAGS_CONSOLE	(1 << 1)
#define PSTORE_FLAGS_FTRACE	(1 << 2)
#define PSTORE_FLAGS_PMSG	(1 << 3)

extern int pstore_register(struct pstore_info *);
extern void pstore_unregister(struct pstore_info *);

struct pstore_ftrace_record {
	unsigned long ip;
	unsigned long parent_ip;
	u64 ts;
};

/*
 * ftrace related stuff: Both backends and frontends need these so expose
 * them here.
 */

#if NR_CPUS <= 2 && defined(CONFIG_ARM_THUMB)
#define PSTORE_CPU_IN_IP 0x1
#elif NR_CPUS <= 4 && defined(CONFIG_ARM)
#define PSTORE_CPU_IN_IP 0x3
#endif

#define TS_CPU_SHIFT 8
#define TS_CPU_MASK (BIT(TS_CPU_SHIFT) - 1)

/*
 * If CPU number can be stored in IP, store it there, otherwise store it in
 * the time stamp. This means more timestamp resolution is available when
 * the CPU can be stored in the IP.
 */
#ifdef PSTORE_CPU_IN_IP
static inline void
pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
{
	rec->ip |= cpu;
}

static inline unsigned int
pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
{
	return rec->ip & PSTORE_CPU_IN_IP;
}

static inline u64
pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
{
	return rec->ts;
}

static inline void
pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
{
	rec->ts = val;
}
#else
static inline void
pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
{
	rec->ts &= ~(TS_CPU_MASK);
	rec->ts |= cpu;
}

static inline unsigned int
pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
{
	return rec->ts & TS_CPU_MASK;
}

static inline u64
pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
{
	return rec->ts >> TS_CPU_SHIFT;
}

static inline void
pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
{
	rec->ts = (rec->ts & TS_CPU_MASK) | (val << TS_CPU_SHIFT);
}
#endif

#endif /*_LINUX_PSTORE_H*/
Commit	Line	Data
ca01d6dd TL	1	/*
	2	* Persistent Storage - pstore.h
	3	*
	4	* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
	5	*
	6	* This code is the generic layer to export data records from platform
	7	* level persistent storage via a file system.
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2 as
	11	* published by the Free Software Foundation.
	12	*
	13	* This program is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	* GNU General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU General Public License
	19	* along with this program; if not, write to the Free Software
	20	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	21	*/
	22	#ifndef _LINUX_PSTORE_H
	23	#define _LINUX_PSTORE_H
	24
5bf6d1b9 MS	25	#include <linux/compiler.h>
5bf6d1b9 MS	26	#include <linux/errno.h>
3d6d8d20	27	#include <linux/kmsg_dump.h>
67a101f5	28	#include <linux/mutex.h>
dca6d5e2	29	#include <linux/semaphore.h>
5bf6d1b9 MS	30	#include <linux/time.h>
5bf6d1b9 MS	31	#include <linux/types.h>
3d6d8d20	32
9abdcccc KC	33	struct module;
9abdcccc KC	34
0edae0b3	35	/* pstore record types (see fs/pstore/inode.c for filename templates) */
ca01d6dd TL	36	enum pstore_type_id {
	37	PSTORE_TYPE_DMESG = 0,
	38	PSTORE_TYPE_MCE = 1,
f29e5956	39	PSTORE_TYPE_CONSOLE = 2,
060287b8	40	PSTORE_TYPE_FTRACE = 3,
69020eea AB	41	/* PPC64 partition types */
69020eea AB	42	PSTORE_TYPE_PPC_RTAS = 4,
f33f748c	43	PSTORE_TYPE_PPC_OF = 5,
a5e4797b	44	PSTORE_TYPE_PPC_COMMON = 6,
9d5438f4	45	PSTORE_TYPE_PMSG = 7,
ae011d2e	46	PSTORE_TYPE_PPC_OPAL = 8,
ca01d6dd TL	47	PSTORE_TYPE_UNKNOWN = 255
	48	};
	49
9abdcccc KC	50	struct pstore_info;
	51	/**
	52	* struct pstore_record - details of a pstore record entry
	53	* @psi: pstore backend driver information
	54	* @type: pstore record type
	55	* @id: per-type unique identifier for record
	56	* @time: timestamp of the record
9abdcccc KC	57	* @buf: pointer to record contents
	58	* @size: size of @buf
	59	* @ecc_notice_size:
	60	* ECC information for @buf
76cc9580 KC	61	*
	62	* Valid for PSTORE_TYPE_DMESG @type:
	63	*
	64	* @count: Oops count since boot
	65	* @reason: kdump reason for notification
	66	* @part: position in a multipart record
	67	* @compressed: whether the buffer is compressed
	68	*
9abdcccc KC	69	*/
	70	struct pstore_record {
	71	struct pstore_info *psi;
	72	enum pstore_type_id type;
	73	u64 id;
	74	struct timespec time;
9abdcccc KC	75	char *buf;
	76	ssize_t size;
	77	ssize_t ecc_notice_size;
76cc9580 KC	78
	79	int count;
	80	enum kmsg_dump_reason reason;
	81	unsigned int part;
	82	bool compressed;
9abdcccc	83	};
67a101f5	84
0edae0b3 KC	85	/**
	86	* struct pstore_info - backend pstore driver structure
	87	*
	88	* @owner: module which is repsonsible for this backend driver
	89	* @name: name of the backend driver
	90	*
dca6d5e2	91	* @buf_lock: semaphore to serialize access to @buf
0edae0b3	92	* @buf: preallocated crash dump buffer
d8db87d2 KC	93	* @bufsize: size of @buf available for crash dump bytes (must match
	94	* smallest number of bytes available for writing to a
	95	* backend entry, since compressed bytes don't take kindly
	96	* to being truncated)
0edae0b3 KC	97	*
	98	* @read_mutex: serializes @open, @read, @close, and @erase callbacks
	99	* @flags: bitfield of frontends the backend can accept writes for
	100	* @data: backend-private pointer passed back during callbacks
	101	*
	102	* Callbacks:
	103	*
	104	* @open:
	105	* Notify backend that pstore is starting a full read of backend
	106	* records. Followed by one or more @read calls, and a final @close.
	107	*
	108	* @psi: in: pointer to the struct pstore_info for the backend
	109	*
	110	* Returns 0 on success, and non-zero on error.
	111	*
	112	* @close:
	113	* Notify backend that pstore has finished a full read of backend
	114	* records. Always preceded by an @open call and one or more @read
	115	* calls.
	116	*
	117	* @psi: in: pointer to the struct pstore_info for the backend
	118	*
	119	* Returns 0 on success, and non-zero on error. (Though pstore will
	120	* ignore the error.)
	121	*
	122	* @read:
	123	* Read next available backend record. Called after a successful
	124	* @open.
	125	*
125cc42b KC	126	* @record:
	127	* pointer to record to populate. @buf should be allocated
	128	* by the backend and filled. At least @type and @id should
	129	* be populated, since these are used when creating pstorefs
	130	* file names.
0edae0b3 KC	131	*
	132	* Returns record size on success, zero when no more records are
	133	* available, or negative on error.
	134	*
	135	* @write:
4c9ec219	136	* A newly generated record needs to be written to backend storage.
0edae0b3	137	*
76cc9580	138	* @record:
4c9ec219 KC	139	* pointer to record metadata. When @type is PSTORE_TYPE_DMESG,
	140	* @buf will be pointing to the preallocated @psi.buf, since
	141	* memory allocation may be broken during an Oops. Regardless,
	142	* @buf must be proccesed or copied before returning. The
	143	* backend is also expected to write @id with something that
c7f3c595 KC	144	* can help identify this record to a future @erase callback.
	145	* The @time field will be prepopulated with the current time,
	146	* when available. The @size field will have the size of data
	147	* in @buf.
0edae0b3 KC	148	*
	149	* Returns 0 on success, and non-zero on error.
	150	*
4c9ec219	151	* @write_user:
0edae0b3	152	* Perform a frontend write to a backend record, using a specified
fdd03118 KC	153	* buffer that is coming directly from userspace, instead of the
	154	* @record @buf.
	155	*
	156	* @record: pointer to record metadata.
	157	* @buf: pointer to userspace contents to write to backend
0edae0b3 KC	158	*
	159	* Returns 0 on success, and non-zero on error.
	160	*
	161	* @erase:
	162	* Delete a record from backend storage. Different backends
a61072aa KC	163	* identify records differently, so entire original record is
	164	* passed back to assist in identification of what the backend
	165	* should remove from storage.
0edae0b3	166	*
a61072aa	167	* @record: pointer to record metadata.
0edae0b3 KC	168	*
	169	* Returns 0 on success, and non-zero on error.
	170	*
	171	*/
ca01d6dd TL	172	struct pstore_info {
	173	struct module *owner;
	174	char *name;
0edae0b3	175
dca6d5e2	176	struct semaphore buf_lock;
ca01d6dd TL	177	char *buf;
ca01d6dd TL	178	size_t bufsize;
0edae0b3 KC	179
	180	struct mutex read_mutex;
	181
df36ac1b	182	int flags;
0edae0b3 KC	183	void *data;
0edae0b3 KC	184
06cf91b4 CG	185	int (open)(struct pstore_info psi);
06cf91b4 CG	186	int (close)(struct pstore_info psi);
125cc42b	187	ssize_t (read)(struct pstore_record record);
76cc9580	188	int (write)(struct pstore_record record);
4c9ec219 KC	189	int (write_user)(struct pstore_record record,
4c9ec219 KC	190	const char __user *buf);
a61072aa	191	int (erase)(struct pstore_record record);
ca01d6dd TL	192	};
ca01d6dd TL	193
0edae0b3	194	/* Supported frontends */
c950fd6f	195	#define PSTORE_FLAGS_DMESG (1 << 0)
c950fd6f NK	196	#define PSTORE_FLAGS_CONSOLE (1 << 1)
	197	#define PSTORE_FLAGS_FTRACE (1 << 2)
	198	#define PSTORE_FLAGS_PMSG (1 << 3)
	199
ca01d6dd	200	extern int pstore_register(struct pstore_info *);
ee1d2674	201	extern void pstore_unregister(struct pstore_info *);
ca01d6dd	202
fbccdeb8 JF	203	struct pstore_ftrace_record {
	204	unsigned long ip;
	205	unsigned long parent_ip;
	206	u64 ts;
	207	};
	208
	209	/*
	210	* ftrace related stuff: Both backends and frontends need these so expose
	211	* them here.
	212	*/
	213
	214	#if NR_CPUS <= 2 && defined(CONFIG_ARM_THUMB)
	215	#define PSTORE_CPU_IN_IP 0x1
	216	#elif NR_CPUS <= 4 && defined(CONFIG_ARM)
	217	#define PSTORE_CPU_IN_IP 0x3
	218	#endif
	219
	220	#define TS_CPU_SHIFT 8
	221	#define TS_CPU_MASK (BIT(TS_CPU_SHIFT) - 1)
	222
	223	/*
	224	* If CPU number can be stored in IP, store it there, otherwise store it in
	225	* the time stamp. This means more timestamp resolution is available when
	226	* the CPU can be stored in the IP.
	227	*/
	228	#ifdef PSTORE_CPU_IN_IP
	229	static inline void
	230	pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
	231	{
	232	rec->ip \|= cpu;
	233	}
	234
	235	static inline unsigned int
	236	pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
	237	{
	238	return rec->ip & PSTORE_CPU_IN_IP;
	239	}
	240
	241	static inline u64
	242	pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
	243	{
	244	return rec->ts;
	245	}
	246
	247	static inline void
	248	pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
	249	{
	250	rec->ts = val;
	251	}
	252	#else
	253	static inline void
	254	pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
	255	{
	256	rec->ts &= ~(TS_CPU_MASK);
	257	rec->ts \|= cpu;
	258	}
	259
	260	static inline unsigned int
	261	pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
	262	{
	263	return rec->ts & TS_CPU_MASK;
	264	}
	265
	266	static inline u64
267	pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
268	{
269	return rec->ts >> TS_CPU_SHIFT;
270	}
271
272	static inline void
273	pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
274	{
275	rec->ts = (rec->ts & TS_CPU_MASK) \| (val << TS_CPU_SHIFT);
276	}
277	#endif
278
ca01d6dd	279	#endif /_LINUX_PSTORE_H/