[linux-2.6-block.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/platform.c for pstore_type_names[])
 * These values may be written to storage (see EFI vars backend), so
 * they are kind of an ABI. Be careful changing the mappings.
 */
enum pstore_type_id {
	/* Frontend storage types */
	PSTORE_TYPE_DMESG	= 0,
	PSTORE_TYPE_MCE		= 1,
	PSTORE_TYPE_CONSOLE	= 2,
	PSTORE_TYPE_FTRACE	= 3,

	/* PPC64-specific 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,

	/* End of the list */
	PSTORE_TYPE_MAX
};

const char *pstore_type_to_name(enum pstore_type_id type);
enum pstore_type_id pstore_name_to_type(const char *name);

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 timespec64	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 responsible 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	BIT(0)
#define PSTORE_FLAGS_CONSOLE	BIT(1)
#define PSTORE_FLAGS_FTRACE	BIT(2)
#define PSTORE_FLAGS_PMSG	BIT(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>
ea84b580	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
f0f23e54 JFG	35	/*
	36	* pstore record types (see fs/pstore/platform.c for pstore_type_names[])
	37	* These values may be written to storage (see EFI vars backend), so
	38	* they are kind of an ABI. Be careful changing the mappings.
	39	*/
ca01d6dd	40	enum pstore_type_id {
f0f23e54	41	/* Frontend storage types */
ca01d6dd TL	42	PSTORE_TYPE_DMESG = 0,
ca01d6dd TL	43	PSTORE_TYPE_MCE = 1,
f29e5956	44	PSTORE_TYPE_CONSOLE = 2,
060287b8	45	PSTORE_TYPE_FTRACE = 3,
f0f23e54 JFG	46
f0f23e54 JFG	47	/* PPC64-specific partition types */
69020eea	48	PSTORE_TYPE_PPC_RTAS = 4,
f33f748c	49	PSTORE_TYPE_PPC_OF = 5,
a5e4797b	50	PSTORE_TYPE_PPC_COMMON = 6,
9d5438f4	51	PSTORE_TYPE_PMSG = 7,
ae011d2e	52	PSTORE_TYPE_PPC_OPAL = 8,
f0f23e54 JFG	53
	54	/* End of the list */
	55	PSTORE_TYPE_MAX
ca01d6dd TL	56	};
ca01d6dd TL	57
f0f23e54 JFG	58	const char *pstore_type_to_name(enum pstore_type_id type);
	59	enum pstore_type_id pstore_name_to_type(const char *name);
	60
9abdcccc KC	61	struct pstore_info;
	62	/**
	63	* struct pstore_record - details of a pstore record entry
	64	* @psi: pstore backend driver information
	65	* @type: pstore record type
	66	* @id: per-type unique identifier for record
	67	* @time: timestamp of the record
9abdcccc KC	68	* @buf: pointer to record contents
	69	* @size: size of @buf
	70	* @ecc_notice_size:
	71	* ECC information for @buf
76cc9580 KC	72	*
	73	* Valid for PSTORE_TYPE_DMESG @type:
	74	*
	75	* @count: Oops count since boot
	76	* @reason: kdump reason for notification
	77	* @part: position in a multipart record
	78	* @compressed: whether the buffer is compressed
	79	*
9abdcccc KC	80	*/
	81	struct pstore_record {
	82	struct pstore_info *psi;
	83	enum pstore_type_id type;
	84	u64 id;
7aaa822e	85	struct timespec64 time;
9abdcccc KC	86	char *buf;
	87	ssize_t size;
	88	ssize_t ecc_notice_size;
76cc9580 KC	89
	90	int count;
	91	enum kmsg_dump_reason reason;
	92	unsigned int part;
	93	bool compressed;
9abdcccc	94	};
67a101f5	95
0edae0b3 KC	96	/**
	97	* struct pstore_info - backend pstore driver structure
	98	*
0eed84ff	99	* @owner: module which is responsible for this backend driver
0edae0b3 KC	100	* @name: name of the backend driver
0edae0b3 KC	101	*
ea84b580	102	* @buf_lock: semaphore to serialize access to @buf
0edae0b3	103	* @buf: preallocated crash dump buffer
89d328f6 KC	104	* @bufsize: size of @buf available for crash dump bytes (must match
	105	* smallest number of bytes available for writing to a
	106	* backend entry, since compressed bytes don't take kindly
	107	* to being truncated)
0edae0b3 KC	108	*
	109	* @read_mutex: serializes @open, @read, @close, and @erase callbacks
	110	* @flags: bitfield of frontends the backend can accept writes for
	111	* @data: backend-private pointer passed back during callbacks
	112	*
	113	* Callbacks:
	114	*
	115	* @open:
	116	* Notify backend that pstore is starting a full read of backend
	117	* records. Followed by one or more @read calls, and a final @close.
	118	*
	119	* @psi: in: pointer to the struct pstore_info for the backend
	120	*
	121	* Returns 0 on success, and non-zero on error.
	122	*
	123	* @close:
	124	* Notify backend that pstore has finished a full read of backend
	125	* records. Always preceded by an @open call and one or more @read
	126	* calls.
	127	*
	128	* @psi: in: pointer to the struct pstore_info for the backend
	129	*
	130	* Returns 0 on success, and non-zero on error. (Though pstore will
	131	* ignore the error.)
	132	*
	133	* @read:
	134	* Read next available backend record. Called after a successful
	135	* @open.
	136	*
125cc42b KC	137	* @record:
	138	* pointer to record to populate. @buf should be allocated
	139	* by the backend and filled. At least @type and @id should
	140	* be populated, since these are used when creating pstorefs
	141	* file names.
0edae0b3 KC	142	*
	143	* Returns record size on success, zero when no more records are
	144	* available, or negative on error.
	145	*
	146	* @write:
4c9ec219	147	* A newly generated record needs to be written to backend storage.
0edae0b3	148	*
76cc9580	149	* @record:
4c9ec219 KC	150	* pointer to record metadata. When @type is PSTORE_TYPE_DMESG,
	151	* @buf will be pointing to the preallocated @psi.buf, since
	152	* memory allocation may be broken during an Oops. Regardless,
	153	* @buf must be proccesed or copied before returning. The
	154	* backend is also expected to write @id with something that
c7f3c595 KC	155	* can help identify this record to a future @erase callback.
	156	* The @time field will be prepopulated with the current time,
	157	* when available. The @size field will have the size of data
	158	* in @buf.
0edae0b3 KC	159	*
	160	* Returns 0 on success, and non-zero on error.
	161	*
4c9ec219	162	* @write_user:
0edae0b3	163	* Perform a frontend write to a backend record, using a specified
fdd03118 KC	164	* buffer that is coming directly from userspace, instead of the
	165	* @record @buf.
	166	*
	167	* @record: pointer to record metadata.
	168	* @buf: pointer to userspace contents to write to backend
0edae0b3 KC	169	*
	170	* Returns 0 on success, and non-zero on error.
	171	*
	172	* @erase:
	173	* Delete a record from backend storage. Different backends
a61072aa KC	174	* identify records differently, so entire original record is
	175	* passed back to assist in identification of what the backend
	176	* should remove from storage.
0edae0b3	177	*
a61072aa	178	* @record: pointer to record metadata.
0edae0b3 KC	179	*
	180	* Returns 0 on success, and non-zero on error.
	181	*
	182	*/
ca01d6dd TL	183	struct pstore_info {
	184	struct module *owner;
	185	char *name;
0edae0b3	186
ea84b580	187	struct semaphore buf_lock;
ca01d6dd TL	188	char *buf;
ca01d6dd TL	189	size_t bufsize;
0edae0b3 KC	190
	191	struct mutex read_mutex;
	192
df36ac1b	193	int flags;
0edae0b3 KC	194	void *data;
0edae0b3 KC	195
06cf91b4 CG	196	int (open)(struct pstore_info psi);
06cf91b4 CG	197	int (close)(struct pstore_info psi);
125cc42b	198	ssize_t (read)(struct pstore_record record);
76cc9580	199	int (write)(struct pstore_record record);
4c9ec219 KC	200	int (write_user)(struct pstore_record record,
4c9ec219 KC	201	const char __user *buf);
a61072aa	202	int (erase)(struct pstore_record record);
ca01d6dd TL	203	};
ca01d6dd TL	204
0edae0b3	205	/* Supported frontends */
4af62a64 KC	206	#define PSTORE_FLAGS_DMESG BIT(0)
	207	#define PSTORE_FLAGS_CONSOLE BIT(1)
	208	#define PSTORE_FLAGS_FTRACE BIT(2)
	209	#define PSTORE_FLAGS_PMSG BIT(3)
c950fd6f	210
ca01d6dd	211	extern int pstore_register(struct pstore_info *);
ee1d2674	212	extern void pstore_unregister(struct pstore_info *);
ca01d6dd	213
fbccdeb8 JF	214	struct pstore_ftrace_record {
	215	unsigned long ip;
	216	unsigned long parent_ip;
	217	u64 ts;
	218	};
	219
	220	/*
	221	* ftrace related stuff: Both backends and frontends need these so expose
	222	* them here.
	223	*/
	224
	225	#if NR_CPUS <= 2 && defined(CONFIG_ARM_THUMB)
	226	#define PSTORE_CPU_IN_IP 0x1
	227	#elif NR_CPUS <= 4 && defined(CONFIG_ARM)
	228	#define PSTORE_CPU_IN_IP 0x3
	229	#endif
	230
	231	#define TS_CPU_SHIFT 8
	232	#define TS_CPU_MASK (BIT(TS_CPU_SHIFT) - 1)
	233
	234	/*
	235	* If CPU number can be stored in IP, store it there, otherwise store it in
	236	* the time stamp. This means more timestamp resolution is available when
	237	* the CPU can be stored in the IP.
	238	*/
	239	#ifdef PSTORE_CPU_IN_IP
	240	static inline void
	241	pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
	242	{
	243	rec->ip \|= cpu;
	244	}
	245
	246	static inline unsigned int
	247	pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
	248	{
	249	return rec->ip & PSTORE_CPU_IN_IP;
	250	}
	251
	252	static inline u64
	253	pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
	254	{
	255	return rec->ts;
	256	}
	257
	258	static inline void
	259	pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
	260	{
	261	rec->ts = val;
	262	}
	263	#else
	264	static inline void
	265	pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
	266	{
	267	rec->ts &= ~(TS_CPU_MASK);
	268	rec->ts \|= cpu;
	269	}
	270
	271	static inline unsigned int
	272	pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
	273	{
	274	return rec->ts & TS_CPU_MASK;
	275	}
	276
	277	static inline u64
278	pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
279	{
280	return rec->ts >> TS_CPU_SHIFT;
281	}
282
283	static inline void
284	pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
285	{
286	rec->ts = (rec->ts & TS_CPU_MASK) \| (val << TS_CPU_SHIFT);
287	}
288	#endif
289
ca01d6dd	290	#endif /_LINUX_PSTORE_H/