1#ifndef _LINUX_RING_BUFFER_H 2#define _LINUX_RING_BUFFER_H 3 4#include <linux/kmemcheck.h> 5#include <linux/mm.h> 6#include <linux/seq_file.h> 7 8struct ring_buffer; 9struct ring_buffer_iter; 10 11/* 12 * Don't refer to this struct directly, use functions below. 13 */ 14struct ring_buffer_event { 15 kmemcheck_bitfield_begin(bitfield); 16 u32 type_len:5, time_delta:27; 17 kmemcheck_bitfield_end(bitfield); 18 19 u32 array[]; 20}; 21 22/** 23 * enum ring_buffer_type - internal ring buffer types 24 * 25 * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event 26 * If time_delta is 0: 27 * array is ignored 28 * size is variable depending on how much 29 * padding is needed 30 * If time_delta is non zero: 31 * array[0] holds the actual length 32 * size = 4 + length (bytes) 33 * 34 * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta 35 * array[0] = time delta (28 .. 59) 36 * size = 8 bytes 37 * 38 * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock 39 * array[0] = tv_nsec 40 * array[1..2] = tv_sec 41 * size = 16 bytes 42 * 43 * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX: 44 * Data record 45 * If type_len is zero: 46 * array[0] holds the actual length 47 * array[1..(length+3)/4] holds data 48 * size = 4 + length (bytes) 49 * else 50 * length = type_len << 2 51 * array[0..(length+3)/4-1] holds data 52 * size = 4 + length (bytes) 53 */ 54enum ring_buffer_type { 55 RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28, 56 RINGBUF_TYPE_PADDING, 57 RINGBUF_TYPE_TIME_EXTEND, 58 RINGBUF_TYPE_TIME_STAMP, 59}; 60 61unsigned ring_buffer_event_length(struct ring_buffer_event *event); 62void *ring_buffer_event_data(struct ring_buffer_event *event); 63 64/** 65 * ring_buffer_event_time_delta - return the delta timestamp of the event 66 * @event: the event to get the delta timestamp of 67 * 68 * The delta timestamp is the 27 bit timestamp since the last event. 69 */ 70static inline unsigned 71ring_buffer_event_time_delta(struct ring_buffer_event *event) 72{ 73 return event->time_delta; 74} 75 76/* 77 * ring_buffer_discard_commit will remove an event that has not 78 * ben committed yet. If this is used, then ring_buffer_unlock_commit 79 * must not be called on the discarded event. This function 80 * will try to remove the event from the ring buffer completely 81 * if another event has not been written after it. 82 * 83 * Example use: 84 * 85 * if (some_condition) 86 * ring_buffer_discard_commit(buffer, event); 87 * else 88 * ring_buffer_unlock_commit(buffer, event); 89 */ 90void ring_buffer_discard_commit(struct ring_buffer *buffer, 91 struct ring_buffer_event *event); 92 93/* 94 * size is in bytes for each per CPU buffer. 95 */ 96struct ring_buffer * 97__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key); 98 99/* 100 * Because the ring buffer is generic, if other users of the ring buffer get 101 * traced by ftrace, it can produce lockdep warnings. We need to keep each 102 * ring buffer's lock class separate. 103 */ 104#define ring_buffer_alloc(size, flags) \ 105({ \ 106 static struct lock_class_key __key; \ 107 __ring_buffer_alloc((size), (flags), &__key); \ 108}) 109 110void ring_buffer_free(struct ring_buffer *buffer); 111 112int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size); 113 114struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer, 115 unsigned long length); 116int ring_buffer_unlock_commit(struct ring_buffer *buffer, 117 struct ring_buffer_event *event); 118int ring_buffer_write(struct ring_buffer *buffer, 119 unsigned long length, void *data); 120 121struct ring_buffer_event * 122ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts, 123 unsigned long *lost_events); 124struct ring_buffer_event * 125ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts, 126 unsigned long *lost_events); 127 128struct ring_buffer_iter * 129ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu); 130void ring_buffer_read_prepare_sync(void); 131void ring_buffer_read_start(struct ring_buffer_iter *iter); 132void ring_buffer_read_finish(struct ring_buffer_iter *iter); 133 134struct ring_buffer_event * 135ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); 136struct ring_buffer_event * 137ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts); 138void ring_buffer_iter_reset(struct ring_buffer_iter *iter); 139int ring_buffer_iter_empty(struct ring_buffer_iter *iter); 140 141unsigned long ring_buffer_size(struct ring_buffer *buffer); 142 143void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu); 144void ring_buffer_reset(struct ring_buffer *buffer); 145 146#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP 147int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 148 struct ring_buffer *buffer_b, int cpu); 149#else 150static inline int 151ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 152 struct ring_buffer *buffer_b, int cpu) 153{ 154 return -ENODEV; 155} 156#endif 157 158int ring_buffer_empty(struct ring_buffer *buffer); 159int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu); 160 161void ring_buffer_record_disable(struct ring_buffer *buffer); 162void ring_buffer_record_enable(struct ring_buffer *buffer); 163void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu); 164void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu); 165 166unsigned long ring_buffer_entries(struct ring_buffer *buffer); 167unsigned long ring_buffer_overruns(struct ring_buffer *buffer); 168unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); 169unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); 170unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu); 171 172u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); 173void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, 174 int cpu, u64 *ts); 175void ring_buffer_set_clock(struct ring_buffer *buffer, 176 u64 (*clock)(void)); 177 178size_t ring_buffer_page_len(void *page); 179 180 181void *ring_buffer_alloc_read_page(struct ring_buffer *buffer); 182void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data); 183int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page, 184 size_t len, int cpu, int full); 185 186struct trace_seq; 187 188int ring_buffer_print_entry_header(struct trace_seq *s); 189int ring_buffer_print_page_header(struct trace_seq *s); 190 191enum ring_buffer_flags { 192 RB_FL_OVERWRITE = 1 << 0, 193}; 194 195#endif /* _LINUX_RING_BUFFER_H */ 196