281 lines
7.6 KiB
C
281 lines
7.6 KiB
C
/*
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* Persistent Storage - pstore.h
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*
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* Copyright (C) 2010 Intel Corporation <tony.luck@intel.com>
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*
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* This code is the generic layer to export data records from platform
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* level persistent storage via a file system.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _LINUX_PSTORE_H
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#define _LINUX_PSTORE_H
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#include <linux/compiler.h>
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#include <linux/errno.h>
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#include <linux/kmsg_dump.h>
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#include <linux/mutex.h>
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#include <linux/spinlock.h>
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#include <linux/time.h>
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#include <linux/types.h>
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struct module;
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/* pstore record types (see fs/pstore/inode.c for filename templates) */
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enum pstore_type_id {
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PSTORE_TYPE_DMESG = 0,
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PSTORE_TYPE_MCE = 1,
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PSTORE_TYPE_CONSOLE = 2,
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PSTORE_TYPE_FTRACE = 3,
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/* PPC64 partition types */
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PSTORE_TYPE_PPC_RTAS = 4,
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PSTORE_TYPE_PPC_OF = 5,
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PSTORE_TYPE_PPC_COMMON = 6,
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PSTORE_TYPE_PMSG = 7,
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PSTORE_TYPE_PPC_OPAL = 8,
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PSTORE_TYPE_UNKNOWN = 255
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};
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struct pstore_info;
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/**
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* struct pstore_record - details of a pstore record entry
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* @psi: pstore backend driver information
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* @type: pstore record type
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* @id: per-type unique identifier for record
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* @time: timestamp of the record
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* @buf: pointer to record contents
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* @size: size of @buf
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* @ecc_notice_size:
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* ECC information for @buf
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*
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* Valid for PSTORE_TYPE_DMESG @type:
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*
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* @count: Oops count since boot
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* @reason: kdump reason for notification
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* @part: position in a multipart record
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* @compressed: whether the buffer is compressed
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*
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*/
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struct pstore_record {
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struct pstore_info *psi;
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enum pstore_type_id type;
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u64 id;
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struct timespec64 time;
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char *buf;
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ssize_t size;
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ssize_t ecc_notice_size;
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int count;
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enum kmsg_dump_reason reason;
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unsigned int part;
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bool compressed;
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};
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/**
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* struct pstore_info - backend pstore driver structure
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*
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* @owner: module which is repsonsible for this backend driver
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* @name: name of the backend driver
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*
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* @buf_lock: spinlock to serialize access to @buf
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* @buf: preallocated crash dump buffer
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* @bufsize: size of @buf available for crash dump bytes (must match
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* smallest number of bytes available for writing to a
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* backend entry, since compressed bytes don't take kindly
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* to being truncated)
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*
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* @read_mutex: serializes @open, @read, @close, and @erase callbacks
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* @flags: bitfield of frontends the backend can accept writes for
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* @data: backend-private pointer passed back during callbacks
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*
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* Callbacks:
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*
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* @open:
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* Notify backend that pstore is starting a full read of backend
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* records. Followed by one or more @read calls, and a final @close.
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*
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* @psi: in: pointer to the struct pstore_info for the backend
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*
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* Returns 0 on success, and non-zero on error.
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*
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* @close:
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* Notify backend that pstore has finished a full read of backend
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* records. Always preceded by an @open call and one or more @read
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* calls.
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*
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* @psi: in: pointer to the struct pstore_info for the backend
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*
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* Returns 0 on success, and non-zero on error. (Though pstore will
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* ignore the error.)
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*
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* @read:
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* Read next available backend record. Called after a successful
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* @open.
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*
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* @record:
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* pointer to record to populate. @buf should be allocated
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* by the backend and filled. At least @type and @id should
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* be populated, since these are used when creating pstorefs
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* file names.
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*
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* Returns record size on success, zero when no more records are
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* available, or negative on error.
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*
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* @write:
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* A newly generated record needs to be written to backend storage.
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*
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* @record:
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* pointer to record metadata. When @type is PSTORE_TYPE_DMESG,
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* @buf will be pointing to the preallocated @psi.buf, since
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* memory allocation may be broken during an Oops. Regardless,
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* @buf must be proccesed or copied before returning. The
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* backend is also expected to write @id with something that
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* can help identify this record to a future @erase callback.
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* The @time field will be prepopulated with the current time,
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* when available. The @size field will have the size of data
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* in @buf.
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*
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* Returns 0 on success, and non-zero on error.
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*
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* @write_user:
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* Perform a frontend write to a backend record, using a specified
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* buffer that is coming directly from userspace, instead of the
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* @record @buf.
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*
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* @record: pointer to record metadata.
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* @buf: pointer to userspace contents to write to backend
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*
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* Returns 0 on success, and non-zero on error.
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*
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* @erase:
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* Delete a record from backend storage. Different backends
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* identify records differently, so entire original record is
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* passed back to assist in identification of what the backend
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* should remove from storage.
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*
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* @record: pointer to record metadata.
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*
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* Returns 0 on success, and non-zero on error.
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*
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*/
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struct pstore_info {
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struct module *owner;
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char *name;
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spinlock_t buf_lock;
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char *buf;
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size_t bufsize;
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struct mutex read_mutex;
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int flags;
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void *data;
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int (*open)(struct pstore_info *psi);
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int (*close)(struct pstore_info *psi);
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ssize_t (*read)(struct pstore_record *record);
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int (*write)(struct pstore_record *record);
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int (*write_user)(struct pstore_record *record,
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const char __user *buf);
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int (*erase)(struct pstore_record *record);
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};
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/* Supported frontends */
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#define PSTORE_FLAGS_DMESG (1 << 0)
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#define PSTORE_FLAGS_CONSOLE (1 << 1)
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#define PSTORE_FLAGS_FTRACE (1 << 2)
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#define PSTORE_FLAGS_PMSG (1 << 3)
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extern int pstore_register(struct pstore_info *);
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extern void pstore_unregister(struct pstore_info *);
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extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);
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struct pstore_ftrace_record {
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unsigned long ip;
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unsigned long parent_ip;
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u64 ts;
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};
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/*
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* ftrace related stuff: Both backends and frontends need these so expose
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* them here.
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*/
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#if NR_CPUS <= 2 && defined(CONFIG_ARM_THUMB)
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#define PSTORE_CPU_IN_IP 0x1
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#elif NR_CPUS <= 4 && defined(CONFIG_ARM)
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#define PSTORE_CPU_IN_IP 0x3
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#endif
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#define TS_CPU_SHIFT 8
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#define TS_CPU_MASK (BIT(TS_CPU_SHIFT) - 1)
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/*
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* If CPU number can be stored in IP, store it there, otherwise store it in
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* the time stamp. This means more timestamp resolution is available when
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* the CPU can be stored in the IP.
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*/
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#ifdef PSTORE_CPU_IN_IP
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static inline void
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pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
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{
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rec->ip |= cpu;
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}
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static inline unsigned int
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pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
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{
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return rec->ip & PSTORE_CPU_IN_IP;
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}
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static inline u64
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pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
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{
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return rec->ts;
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}
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static inline void
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pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
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{
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rec->ts = val;
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}
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#else
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static inline void
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pstore_ftrace_encode_cpu(struct pstore_ftrace_record *rec, unsigned int cpu)
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{
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rec->ts &= ~(TS_CPU_MASK);
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rec->ts |= cpu;
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}
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static inline unsigned int
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pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
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{
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return rec->ts & TS_CPU_MASK;
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}
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static inline u64
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pstore_ftrace_read_timestamp(struct pstore_ftrace_record *rec)
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{
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return rec->ts >> TS_CPU_SHIFT;
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}
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static inline void
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pstore_ftrace_write_timestamp(struct pstore_ftrace_record *rec, u64 val)
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{
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rec->ts = (rec->ts & TS_CPU_MASK) | (val << TS_CPU_SHIFT);
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}
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#endif
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#endif /*_LINUX_PSTORE_H*/
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