| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* |
| * 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. |
| */ |
| #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 |
| * @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; |
| |
| struct semaphore 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*/ |