#ifndef _LINUX_RING_BUFFER_H #define _LINUX_RING_BUFFER_H #include <linux/kmemcheck.h> #include <linux/mm.h> #include <linux/seq_file.h> struct ring_buffer; struct ring_buffer_iter; /* * Don't refer to this struct directly, use functions below. */ struct ring_buffer_event { kmemcheck_bitfield_begin(bitfield); u32 type_len:5, time_delta:27; kmemcheck_bitfield_end(bitfield); u32 array[]; }; /** * 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: Sync time stamp with external clock * array[0] = tv_nsec * array[1..2] = tv_sec * size = 16 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 { RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28, RINGBUF_TYPE_PADDING, RINGBUF_TYPE_TIME_EXTEND, /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */ RINGBUF_TYPE_TIME_STAMP, }; unsigned ring_buffer_event_length(struct ring_buffer_event *event); void *ring_buffer_event_data(struct ring_buffer_event *event); /** * ring_buffer_event_time_delta - return the delta timestamp of the event * @event: the event to get the delta timestamp of * * The delta timestamp is the 27 bit timestamp since the last event. */ static inline unsigned ring_buffer_event_time_delta(struct ring_buffer_event *event) { return event->time_delta; } /* * ring_buffer_event_discard can discard any event in the ring buffer. * it is up to the caller to protect against a reader from * consuming it or a writer from wrapping and replacing it. * * No external protection is needed if this is called before * the event is commited. But in that case it would be better to * use ring_buffer_discard_commit. * * Note, if an event that has not been committed is discarded * with ring_buffer_event_discard, it must still be committed. */ void ring_buffer_event_discard(struct ring_buffer_event *event); /* * ring_buffer_discard_commit will remove an event that has not * ben 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 ring_buffer *buffer, struct ring_buffer_event *event); /* * size is in bytes for each per CPU buffer. */ struct ring_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) \ ({ \ static struct lock_class_key __key; \ __ring_buffer_alloc((size), (flags), &__key); \ }) void ring_buffer_free(struct ring_buffer *buffer); int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size); struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length); int ring_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event); int ring_buffer_write(struct ring_buffer *buffer, unsigned long length, void *data); struct ring_buffer_event * ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts); struct ring_buffer_event * ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts); struct ring_buffer_iter * ring_buffer_read_start(struct ring_buffer *buffer, int cpu); 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); struct ring_buffer_event * ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts); void ring_buffer_iter_reset(struct ring_buffer_iter *iter); int ring_buffer_iter_empty(struct ring_buffer_iter *iter); unsigned long ring_buffer_size(struct ring_buffer *buffer); void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu); void ring_buffer_reset(struct ring_buffer *buffer); int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, struct ring_buffer *buffer_b, int cpu); int ring_buffer_empty(struct ring_buffer *buffer); int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu); void ring_buffer_record_disable(struct ring_buffer *buffer); void ring_buffer_record_enable(struct ring_buffer *buffer); void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu); void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu); unsigned long ring_buffer_entries(struct ring_buffer *buffer); unsigned long ring_buffer_overruns(struct ring_buffer *buffer); unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu); unsigned long ring_buffer_nmi_dropped_cpu(struct ring_buffer *buffer, int cpu); u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, int cpu, u64 *ts); void ring_buffer_set_clock(struct ring_buffer *buffer, u64 (*clock)(void)); size_t ring_buffer_page_len(void *page); void *ring_buffer_alloc_read_page(struct ring_buffer *buffer); void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data); int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page, size_t len, int cpu, int full); struct trace_seq; int ring_buffer_print_entry_header(struct trace_seq *s); int ring_buffer_print_page_header(struct trace_seq *s); enum ring_buffer_flags { RB_FL_OVERWRITE = 1 << 0, }; #endif /* _LINUX_RING_BUFFER_H */