diff -drupN a/include/linux/pstore.h b/include/linux/pstore.h
--- a/include/linux/pstore.h 2018-08-06 17:23:04.000000000 +0300
+++ b/include/linux/pstore.h 2022-06-12 05:28:14.000000000 +0300
@@ -26,67 +26,265 @@
#include <linux/errno.h>
#include <linux/kmsg_dump.h>
#include <linux/mutex.h>
-#include <linux/spinlock.h>
+#include <linux/semaphore.h>
#include <linux/time.h>
#include <linux/types.h>
-/* types */
+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 partition types */
+
+ /* 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,
- PSTORE_TYPE_UNKNOWN = 255
+
+ /* End of the list */
+ PSTORE_TYPE_MAX
};
-struct module;
+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
+ * @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;
char *name;
- spinlock_t buf_lock; /* serialize access to 'buf' */
+
+ struct semaphore buf_lock;
char *buf;
size_t bufsize;
- struct mutex read_mutex; /* serialize open/read/close */
+
+ struct mutex read_mutex;
+
int flags;
+ void *data;
+
int (*open)(struct pstore_info *psi);
int (*close)(struct pstore_info *psi);
- ssize_t (*read)(u64 *id, enum pstore_type_id *type,
- int *count, struct timespec *time, char **buf,
- bool *compressed, ssize_t *ecc_notice_size,
- struct pstore_info *psi);
- int (*write)(enum pstore_type_id type,
- enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, int count, bool compressed,
- size_t size, struct pstore_info *psi);
- int (*write_buf)(enum pstore_type_id type,
- enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, const char *buf, bool compressed,
- size_t size, struct pstore_info *psi);
- int (*write_buf_user)(enum pstore_type_id type,
- enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, const char __user *buf,
- bool compressed, size_t size, struct pstore_info *psi);
- int (*erase)(enum pstore_type_id type, u64 id,
- int count, struct timespec time,
- struct pstore_info *psi);
- void *data;
+ 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);
};
-#define PSTORE_FLAGS_DMESG (1 << 0)
-#define PSTORE_FLAGS_FRAGILE PSTORE_FLAGS_DMESG
-#define PSTORE_FLAGS_CONSOLE (1 << 1)
-#define PSTORE_FLAGS_FTRACE (1 << 2)
-#define PSTORE_FLAGS_PMSG (1 << 3)
+/* 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 *);
-extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);
+
+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*/