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- /* SPDX-License-Identifier: GPL-2.0-only */
- /*
- * Persistent Storage - pstore.h
- *
- * Copyright (C) 2010 Intel Corporation <[email protected]>
- *
- * This code is the generic layer to export data records from platform
- * level persistent storage via a file system.
- */
- #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/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
- * @priv: pointer for backend specific use, will be
- * kfree()d by the pstore core if non-NULL
- * when the record is freed.
- *
- * 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;
- void *priv;
- 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: spinlock 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
- * @max_reason: Used when PSTORE_FLAGS_DMESG is set. Contains the
- * kmsg_dump_reason enum value. KMSG_DUMP_UNDEF means
- * "use existing kmsg_dump() filtering, based on the
- * printk.always_kmsg_dump boot param" (which is either
- * KMSG_DUMP_OOPS when false, or KMSG_DUMP_MAX when
- * true); see printk.always_kmsg_dump for more details.
- * @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;
- const char *name;
- spinlock_t buf_lock;
- char *buf;
- size_t bufsize;
- struct mutex read_mutex;
- int flags;
- int max_reason;
- 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*/
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