cregit-Linux how code gets into the kernel

Release 4.12 include/linux/pstore.h

Directory: include/linux
/*
 * 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/spinlock.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:   spinlock to serialize access to @buf
 * @buf:        preallocated crash dump buffer
 * @bufsize:    size of @buf available for crash dump writes
 *
 * @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
 8              can help identify this record to a future @erase callback.
 *
 *      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;

	
spinlock_t	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 *);
extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);


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; }

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

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

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Joel Fernandes17100.00%1100.00%
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static inline void pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val) { rec->ts = val; }

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Joel Fernandes21100.00%1100.00%
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#else
static inline void pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu) { rec->ts &= ~(TS_CPU_MASK); rec->ts |= cpu; }

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Joel Fernandes31100.00%1100.00%
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static inline unsigned int pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec) { return rec->ts & TS_CPU_MASK; }

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Joel Fernandes20100.00%1100.00%
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static inline u64 pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec) { return rec->ts >> TS_CPU_SHIFT; }

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Joel Fernandes19100.00%1100.00%
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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); }

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#endif #endif /*_LINUX_PSTORE_H*/

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Joel Fernandes24646.15%13.23%
Tony Luck8716.32%26.45%
Kees Cook7614.26%929.03%
Chen Gong264.88%39.68%
Anton Vorontsov224.13%412.90%
Mark Salyzyn224.13%26.45%
Namhyung Kim163.00%13.23%
Aruna Balakrishnaiah132.44%39.68%
Seiji Aguchi91.69%26.45%
Matthew Garrett50.94%13.23%
Geliang Tang50.94%13.23%
Hari Bathini40.75%13.23%
Don Zickus20.38%13.23%
Total533100.00%31100.00%
Directory: include/linux
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