1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_RING_BUFFER_H 3#define _LINUX_RING_BUFFER_H 4 5#include <linux/mm.h> 6#include <linux/seq_file.h> 7#include <linux/poll.h> 8 9struct trace_buffer; 10struct ring_buffer_iter; 11 12/* 13 * Don't refer to this struct directly, use functions below. 14 */ 15struct ring_buffer_event { 16 u32 type_len:5, time_delta:27; 17 18 u32 array[]; 19}; 20 21/** 22 * enum ring_buffer_type - internal ring buffer types 23 * 24 * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event 25 * If time_delta is 0: 26 * array is ignored 27 * size is variable depending on how much 28 * padding is needed 29 * If time_delta is non zero: 30 * array[0] holds the actual length 31 * size = 4 + length (bytes) 32 * 33 * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta 34 * array[0] = time delta (28 .. 59) 35 * size = 8 bytes 36 * 37 * @RINGBUF_TYPE_TIME_STAMP: Absolute timestamp 38 * Same format as TIME_EXTEND except that the 39 * value is an absolute timestamp, not a delta 40 * event.time_delta contains bottom 27 bits 41 * array[0] = top (28 .. 59) bits 42 * size = 8 bytes 43 * 44 * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX: 45 * Data record 46 * If type_len is zero: 47 * array[0] holds the actual length 48 * array[1..(length+3)/4] holds data 49 * size = 4 + length (bytes) 50 * else 51 * length = type_len << 2 52 * array[0..(length+3)/4-1] holds data 53 * size = 4 + length (bytes) 54 */ 55enum ring_buffer_type { 56 RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28, 57 RINGBUF_TYPE_PADDING, 58 RINGBUF_TYPE_TIME_EXTEND, 59 RINGBUF_TYPE_TIME_STAMP, 60}; 61 62unsigned ring_buffer_event_length(struct ring_buffer_event *event); 63void *ring_buffer_event_data(struct ring_buffer_event *event); 64u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer, 65 struct ring_buffer_event *event); 66 67/* 68 * ring_buffer_discard_commit will remove an event that has not 69 * been committed yet. If this is used, then ring_buffer_unlock_commit 70 * must not be called on the discarded event. This function 71 * will try to remove the event from the ring buffer completely 72 * if another event has not been written after it. 73 * 74 * Example use: 75 * 76 * if (some_condition) 77 * ring_buffer_discard_commit(buffer, event); 78 * else 79 * ring_buffer_unlock_commit(buffer, event); 80 */ 81void ring_buffer_discard_commit(struct trace_buffer *buffer, 82 struct ring_buffer_event *event); 83 84/* 85 * size is in bytes for each per CPU buffer. 86 */ 87struct trace_buffer * 88__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key); 89 90/* 91 * Because the ring buffer is generic, if other users of the ring buffer get 92 * traced by ftrace, it can produce lockdep warnings. We need to keep each 93 * ring buffer's lock class separate. 94 */ 95#define ring_buffer_alloc(size, flags) \ 96({ \ 97 static struct lock_class_key __key; \ 98 __ring_buffer_alloc((size), (flags), &__key); \ 99}) 100 101typedef bool (*ring_buffer_cond_fn)(void *data); 102int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full, 103 ring_buffer_cond_fn cond, void *data); 104__poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, 105 struct file *filp, poll_table *poll_table, int full); 106void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu); 107 108#define RING_BUFFER_ALL_CPUS -1 109 110void ring_buffer_free(struct trace_buffer *buffer); 111 112int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu); 113 114void ring_buffer_change_overwrite(struct trace_buffer *buffer, int val); 115 116struct ring_buffer_event *ring_buffer_lock_reserve(struct trace_buffer *buffer, 117 unsigned long length); 118int ring_buffer_unlock_commit(struct trace_buffer *buffer); 119int ring_buffer_write(struct trace_buffer *buffer, 120 unsigned long length, void *data); 121 122void ring_buffer_nest_start(struct trace_buffer *buffer); 123void ring_buffer_nest_end(struct trace_buffer *buffer); 124 125struct ring_buffer_event * 126ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts, 127 unsigned long *lost_events); 128struct ring_buffer_event * 129ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts, 130 unsigned long *lost_events); 131 132struct ring_buffer_iter * 133ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags); 134void ring_buffer_read_prepare_sync(void); 135void ring_buffer_read_start(struct ring_buffer_iter *iter); 136void ring_buffer_read_finish(struct ring_buffer_iter *iter); 137 138struct ring_buffer_event * 139ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); 140void ring_buffer_iter_advance(struct ring_buffer_iter *iter); 141void ring_buffer_iter_reset(struct ring_buffer_iter *iter); 142int ring_buffer_iter_empty(struct ring_buffer_iter *iter); 143bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter); 144 145unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu); 146unsigned long ring_buffer_max_event_size(struct trace_buffer *buffer); 147 148void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu); 149void ring_buffer_reset_online_cpus(struct trace_buffer *buffer); 150void ring_buffer_reset(struct trace_buffer *buffer); 151 152#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP 153int ring_buffer_swap_cpu(struct trace_buffer *buffer_a, 154 struct trace_buffer *buffer_b, int cpu); 155#else 156static inline int 157ring_buffer_swap_cpu(struct trace_buffer *buffer_a, 158 struct trace_buffer *buffer_b, int cpu) 159{ 160 return -ENODEV; 161} 162#endif 163 164bool ring_buffer_empty(struct trace_buffer *buffer); 165bool ring_buffer_empty_cpu(struct trace_buffer *buffer, int cpu); 166 167void ring_buffer_record_disable(struct trace_buffer *buffer); 168void ring_buffer_record_enable(struct trace_buffer *buffer); 169void ring_buffer_record_off(struct trace_buffer *buffer); 170void ring_buffer_record_on(struct trace_buffer *buffer); 171bool ring_buffer_record_is_on(struct trace_buffer *buffer); 172bool ring_buffer_record_is_set_on(struct trace_buffer *buffer); 173void ring_buffer_record_disable_cpu(struct trace_buffer *buffer, int cpu); 174void ring_buffer_record_enable_cpu(struct trace_buffer *buffer, int cpu); 175 176u64 ring_buffer_oldest_event_ts(struct trace_buffer *buffer, int cpu); 177unsigned long ring_buffer_bytes_cpu(struct trace_buffer *buffer, int cpu); 178unsigned long ring_buffer_entries(struct trace_buffer *buffer); 179unsigned long ring_buffer_overruns(struct trace_buffer *buffer); 180unsigned long ring_buffer_entries_cpu(struct trace_buffer *buffer, int cpu); 181unsigned long ring_buffer_overrun_cpu(struct trace_buffer *buffer, int cpu); 182unsigned long ring_buffer_commit_overrun_cpu(struct trace_buffer *buffer, int cpu); 183unsigned long ring_buffer_dropped_events_cpu(struct trace_buffer *buffer, int cpu); 184unsigned long ring_buffer_read_events_cpu(struct trace_buffer *buffer, int cpu); 185 186u64 ring_buffer_time_stamp(struct trace_buffer *buffer); 187void ring_buffer_normalize_time_stamp(struct trace_buffer *buffer, 188 int cpu, u64 *ts); 189void ring_buffer_set_clock(struct trace_buffer *buffer, 190 u64 (*clock)(void)); 191void ring_buffer_set_time_stamp_abs(struct trace_buffer *buffer, bool abs); 192bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer); 193 194size_t ring_buffer_nr_pages(struct trace_buffer *buffer, int cpu); 195size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu); 196 197struct buffer_data_read_page; 198struct buffer_data_read_page * 199ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu); 200void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, 201 struct buffer_data_read_page *page); 202int ring_buffer_read_page(struct trace_buffer *buffer, 203 struct buffer_data_read_page *data_page, 204 size_t len, int cpu, int full); 205void *ring_buffer_read_page_data(struct buffer_data_read_page *page); 206 207struct trace_seq; 208 209int ring_buffer_print_entry_header(struct trace_seq *s); 210int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s); 211 212int ring_buffer_subbuf_order_get(struct trace_buffer *buffer); 213int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order); 214int ring_buffer_subbuf_size_get(struct trace_buffer *buffer); 215 216enum ring_buffer_flags { 217 RB_FL_OVERWRITE = 1 << 0, 218}; 219 220#ifdef CONFIG_RING_BUFFER 221int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node); 222#else 223#define trace_rb_cpu_prepare NULL 224#endif 225 226#endif /* _LINUX_RING_BUFFER_H */ 227