1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_RING_BUFFER_H
3 #define _LINUX_RING_BUFFER_H
6 #include <linux/seq_file.h>
7 #include <linux/poll.h>
10 struct ring_buffer_iter;
13 * Don't refer to this struct directly, use functions below.
15 struct ring_buffer_event {
16 u32 type_len:5, time_delta:27;
22 * enum ring_buffer_type - internal ring buffer types
24 * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event
27 * size is variable depending on how much
29 * If time_delta is non zero:
30 * array[0] holds the actual length
31 * size = 4 + length (bytes)
33 * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
34 * array[0] = time delta (28 .. 59)
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
44 * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
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)
51 * length = type_len << 2
52 * array[0..(length+3)/4-1] holds data
53 * size = 4 + length (bytes)
55 enum ring_buffer_type {
56 RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
58 RINGBUF_TYPE_TIME_EXTEND,
59 RINGBUF_TYPE_TIME_STAMP,
62 unsigned ring_buffer_event_length(struct ring_buffer_event *event);
63 void *ring_buffer_event_data(struct ring_buffer_event *event);
64 u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer,
65 struct ring_buffer_event *event);
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.
77 * ring_buffer_discard_commit(buffer, event);
79 * ring_buffer_unlock_commit(buffer, event);
81 void ring_buffer_discard_commit(struct trace_buffer *buffer,
82 struct ring_buffer_event *event);
85 * size is in bytes for each per CPU buffer.
88 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
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.
95 #define ring_buffer_alloc(size, flags) \
97 static struct lock_class_key __key; \
98 __ring_buffer_alloc((size), (flags), &__key); \
101 typedef bool (*ring_buffer_cond_fn)(void *data);
102 int 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);
106 void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu);
108 #define RING_BUFFER_ALL_CPUS -1
110 void ring_buffer_free(struct trace_buffer *buffer);
112 int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu);
114 void ring_buffer_change_overwrite(struct trace_buffer *buffer, int val);
116 struct ring_buffer_event *ring_buffer_lock_reserve(struct trace_buffer *buffer,
117 unsigned long length);
118 int ring_buffer_unlock_commit(struct trace_buffer *buffer);
119 int ring_buffer_write(struct trace_buffer *buffer,
120 unsigned long length, void *data);
122 void ring_buffer_nest_start(struct trace_buffer *buffer);
123 void ring_buffer_nest_end(struct trace_buffer *buffer);
125 struct ring_buffer_event *
126 ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts,
127 unsigned long *lost_events);
128 struct ring_buffer_event *
129 ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts,
130 unsigned long *lost_events);
132 struct ring_buffer_iter *
133 ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags);
134 void ring_buffer_read_prepare_sync(void);
135 void ring_buffer_read_start(struct ring_buffer_iter *iter);
136 void ring_buffer_read_finish(struct ring_buffer_iter *iter);
138 struct ring_buffer_event *
139 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
140 void ring_buffer_iter_advance(struct ring_buffer_iter *iter);
141 void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
142 int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
143 bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter);
145 unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu);
146 unsigned long ring_buffer_max_event_size(struct trace_buffer *buffer);
148 void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu);
149 void ring_buffer_reset_online_cpus(struct trace_buffer *buffer);
150 void ring_buffer_reset(struct trace_buffer *buffer);
152 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
153 int ring_buffer_swap_cpu(struct trace_buffer *buffer_a,
154 struct trace_buffer *buffer_b, int cpu);
157 ring_buffer_swap_cpu(struct trace_buffer *buffer_a,
158 struct trace_buffer *buffer_b, int cpu)
164 bool ring_buffer_empty(struct trace_buffer *buffer);
165 bool ring_buffer_empty_cpu(struct trace_buffer *buffer, int cpu);
167 void ring_buffer_record_disable(struct trace_buffer *buffer);
168 void ring_buffer_record_enable(struct trace_buffer *buffer);
169 void ring_buffer_record_off(struct trace_buffer *buffer);
170 void ring_buffer_record_on(struct trace_buffer *buffer);
171 bool ring_buffer_record_is_on(struct trace_buffer *buffer);
172 bool ring_buffer_record_is_set_on(struct trace_buffer *buffer);
173 void ring_buffer_record_disable_cpu(struct trace_buffer *buffer, int cpu);
174 void ring_buffer_record_enable_cpu(struct trace_buffer *buffer, int cpu);
176 u64 ring_buffer_oldest_event_ts(struct trace_buffer *buffer, int cpu);
177 unsigned long ring_buffer_bytes_cpu(struct trace_buffer *buffer, int cpu);
178 unsigned long ring_buffer_entries(struct trace_buffer *buffer);
179 unsigned long ring_buffer_overruns(struct trace_buffer *buffer);
180 unsigned long ring_buffer_entries_cpu(struct trace_buffer *buffer, int cpu);
181 unsigned long ring_buffer_overrun_cpu(struct trace_buffer *buffer, int cpu);
182 unsigned long ring_buffer_commit_overrun_cpu(struct trace_buffer *buffer, int cpu);
183 unsigned long ring_buffer_dropped_events_cpu(struct trace_buffer *buffer, int cpu);
184 unsigned long ring_buffer_read_events_cpu(struct trace_buffer *buffer, int cpu);
186 u64 ring_buffer_time_stamp(struct trace_buffer *buffer);
187 void ring_buffer_normalize_time_stamp(struct trace_buffer *buffer,
189 void ring_buffer_set_clock(struct trace_buffer *buffer,
191 void ring_buffer_set_time_stamp_abs(struct trace_buffer *buffer, bool abs);
192 bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer);
194 size_t ring_buffer_nr_pages(struct trace_buffer *buffer, int cpu);
195 size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu);
197 struct buffer_data_read_page;
198 struct buffer_data_read_page *
199 ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu);
200 void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu,
201 struct buffer_data_read_page *page);
202 int ring_buffer_read_page(struct trace_buffer *buffer,
203 struct buffer_data_read_page *data_page,
204 size_t len, int cpu, int full);
205 void *ring_buffer_read_page_data(struct buffer_data_read_page *page);
209 int ring_buffer_print_entry_header(struct trace_seq *s);
210 int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s);
212 int ring_buffer_subbuf_order_get(struct trace_buffer *buffer);
213 int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order);
214 int ring_buffer_subbuf_size_get(struct trace_buffer *buffer);
216 enum ring_buffer_flags {
217 RB_FL_OVERWRITE = 1 << 0,
220 #ifdef CONFIG_RING_BUFFER
221 int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node);
223 #define trace_rb_cpu_prepare NULL
226 #endif /* _LINUX_RING_BUFFER_H */