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285 lines
7.6 KiB
285 lines
7.6 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* Persistent Storage - pstore.h |
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* |
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* Copyright (C) 2010 Intel Corporation <[email protected]> |
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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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#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/semaphore.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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/* |
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* pstore record types (see fs/pstore/platform.c for pstore_type_names[]) |
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* These values may be written to storage (see EFI vars backend), so |
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* they are kind of an ABI. Be careful changing the mappings. |
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*/ |
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enum pstore_type_id { |
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/* Frontend storage types */ |
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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-specific 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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/* End of the list */ |
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PSTORE_TYPE_MAX |
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}; |
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const char *pstore_type_to_name(enum pstore_type_id type); |
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enum pstore_type_id pstore_name_to_type(const char *name); |
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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 responsible for this backend driver |
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* @name: name of the backend driver |
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* |
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* @buf_lock: semaphore 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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* @max_reason: Used when PSTORE_FLAGS_DMESG is set. Contains the |
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* kmsg_dump_reason enum value. KMSG_DUMP_UNDEF means |
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* "use existing kmsg_dump() filtering, based on the |
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* printk.always_kmsg_dump boot param" (which is either |
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* KMSG_DUMP_OOPS when false, or KMSG_DUMP_MAX when |
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* true); see printk.always_kmsg_dump for more details. |
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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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const char *name; |
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struct semaphore 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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int max_reason; |
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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 BIT(0) |
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#define PSTORE_FLAGS_CONSOLE BIT(1) |
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#define PSTORE_FLAGS_FTRACE BIT(2) |
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#define PSTORE_FLAGS_PMSG BIT(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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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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