/* 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/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; raw_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*/
