/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_RING_BUFFER_H #define _LINUX_RING_BUFFER_H #include <linux/mm.h> #include <linux/seq_file.h> #include <linux/poll.h> #include <uapi/linux/trace_mmap.h> struct trace_buffer; struct ring_buffer_iter; /* * Don't refer to this struct directly, use functions below. */ struct ring_buffer_event { … }; /** * enum ring_buffer_type - internal ring buffer types * * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event * If time_delta is 0: * array is ignored * size is variable depending on how much * padding is needed * If time_delta is non zero: * array[0] holds the actual length * size = 4 + length (bytes) * * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta * array[0] = time delta (28 .. 59) * size = 8 bytes * * @RINGBUF_TYPE_TIME_STAMP: Absolute timestamp * Same format as TIME_EXTEND except that the * value is an absolute timestamp, not a delta * event.time_delta contains bottom 27 bits * array[0] = top (28 .. 59) bits * size = 8 bytes * * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX: * Data record * If type_len is zero: * array[0] holds the actual length * array[1..(length+3)/4] holds data * size = 4 + length (bytes) * else * length = type_len << 2 * array[0..(length+3)/4-1] holds data * size = 4 + length (bytes) */ enum ring_buffer_type { … }; unsigned ring_buffer_event_length(struct ring_buffer_event *event); void *ring_buffer_event_data(struct ring_buffer_event *event); u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer, struct ring_buffer_event *event); /* * ring_buffer_discard_commit will remove an event that has not * been committed yet. If this is used, then ring_buffer_unlock_commit * must not be called on the discarded event. This function * will try to remove the event from the ring buffer completely * if another event has not been written after it. * * Example use: * * if (some_condition) * ring_buffer_discard_commit(buffer, event); * else * ring_buffer_unlock_commit(buffer, event); */ void ring_buffer_discard_commit(struct trace_buffer *buffer, struct ring_buffer_event *event); /* * size is in bytes for each per CPU buffer. */ struct trace_buffer * __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key); /* * Because the ring buffer is generic, if other users of the ring buffer get * traced by ftrace, it can produce lockdep warnings. We need to keep each * ring buffer's lock class separate. */ #define ring_buffer_alloc(size, flags) … ring_buffer_cond_fn; int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full, ring_buffer_cond_fn cond, void *data); __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, struct file *filp, poll_table *poll_table, int full); void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu); #define RING_BUFFER_ALL_CPUS … void ring_buffer_free(struct trace_buffer *buffer); int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu); void ring_buffer_change_overwrite(struct trace_buffer *buffer, int val); struct ring_buffer_event *ring_buffer_lock_reserve(struct trace_buffer *buffer, unsigned long length); int ring_buffer_unlock_commit(struct trace_buffer *buffer); int ring_buffer_write(struct trace_buffer *buffer, unsigned long length, void *data); void ring_buffer_nest_start(struct trace_buffer *buffer); void ring_buffer_nest_end(struct trace_buffer *buffer); struct ring_buffer_event * ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts, unsigned long *lost_events); struct ring_buffer_event * ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts, unsigned long *lost_events); struct ring_buffer_iter * ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags); void ring_buffer_read_prepare_sync(void); void ring_buffer_read_start(struct ring_buffer_iter *iter); void ring_buffer_read_finish(struct ring_buffer_iter *iter); struct ring_buffer_event * ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); void ring_buffer_iter_advance(struct ring_buffer_iter *iter); void ring_buffer_iter_reset(struct ring_buffer_iter *iter); int ring_buffer_iter_empty(struct ring_buffer_iter *iter); bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter); unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu); unsigned long ring_buffer_max_event_size(struct trace_buffer *buffer); void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu); void ring_buffer_reset_online_cpus(struct trace_buffer *buffer); void ring_buffer_reset(struct trace_buffer *buffer); #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP int ring_buffer_swap_cpu(struct trace_buffer *buffer_a, struct trace_buffer *buffer_b, int cpu); #else static inline int ring_buffer_swap_cpu(struct trace_buffer *buffer_a, struct trace_buffer *buffer_b, int cpu) { return -ENODEV; } #endif bool ring_buffer_empty(struct trace_buffer *buffer); bool ring_buffer_empty_cpu(struct trace_buffer *buffer, int cpu); void ring_buffer_record_disable(struct trace_buffer *buffer); void ring_buffer_record_enable(struct trace_buffer *buffer); void ring_buffer_record_off(struct trace_buffer *buffer); void ring_buffer_record_on(struct trace_buffer *buffer); bool ring_buffer_record_is_on(struct trace_buffer *buffer); bool ring_buffer_record_is_set_on(struct trace_buffer *buffer); void ring_buffer_record_disable_cpu(struct trace_buffer *buffer, int cpu); void ring_buffer_record_enable_cpu(struct trace_buffer *buffer, int cpu); u64 ring_buffer_oldest_event_ts(struct trace_buffer *buffer, int cpu); unsigned long ring_buffer_bytes_cpu(struct trace_buffer *buffer, int cpu); unsigned long ring_buffer_entries(struct trace_buffer *buffer); unsigned long ring_buffer_overruns(struct trace_buffer *buffer); unsigned long ring_buffer_entries_cpu(struct trace_buffer *buffer, int cpu); unsigned long ring_buffer_overrun_cpu(struct trace_buffer *buffer, int cpu); unsigned long ring_buffer_commit_overrun_cpu(struct trace_buffer *buffer, int cpu); unsigned long ring_buffer_dropped_events_cpu(struct trace_buffer *buffer, int cpu); unsigned long ring_buffer_read_events_cpu(struct trace_buffer *buffer, int cpu); u64 ring_buffer_time_stamp(struct trace_buffer *buffer); void ring_buffer_normalize_time_stamp(struct trace_buffer *buffer, int cpu, u64 *ts); void ring_buffer_set_clock(struct trace_buffer *buffer, u64 (*clock)(void)); void ring_buffer_set_time_stamp_abs(struct trace_buffer *buffer, bool abs); bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer); size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu); struct buffer_data_read_page; struct buffer_data_read_page * ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu); void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, struct buffer_data_read_page *page); int ring_buffer_read_page(struct trace_buffer *buffer, struct buffer_data_read_page *data_page, size_t len, int cpu, int full); void *ring_buffer_read_page_data(struct buffer_data_read_page *page); struct trace_seq; int ring_buffer_print_entry_header(struct trace_seq *s); int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s); int ring_buffer_subbuf_order_get(struct trace_buffer *buffer); int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order); int ring_buffer_subbuf_size_get(struct trace_buffer *buffer); enum ring_buffer_flags { … }; #ifdef CONFIG_RING_BUFFER int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node); #else #define trace_rb_cpu_prepare … #endif int ring_buffer_map(struct trace_buffer *buffer, int cpu, struct vm_area_struct *vma); int ring_buffer_unmap(struct trace_buffer *buffer, int cpu); int ring_buffer_map_get_reader(struct trace_buffer *buffer, int cpu); #endif /* _LINUX_RING_BUFFER_H */
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