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 ring_buffer_event
*event
);
67 * ring_buffer_discard_commit will remove an event that has not
68 * been committed yet. If this is used, then ring_buffer_unlock_commit
69 * must not be called on the discarded event. This function
70 * will try to remove the event from the ring buffer completely
71 * if another event has not been written after it.
76 * ring_buffer_discard_commit(buffer, event);
78 * ring_buffer_unlock_commit(buffer, event);
80 void ring_buffer_discard_commit(struct ring_buffer
*buffer
,
81 struct ring_buffer_event
*event
);
84 * size is in bytes for each per CPU buffer.
87 __ring_buffer_alloc(unsigned long size
, unsigned flags
, struct lock_class_key
*key
);
90 * Because the ring buffer is generic, if other users of the ring buffer get
91 * traced by ftrace, it can produce lockdep warnings. We need to keep each
92 * ring buffer's lock class separate.
94 #define ring_buffer_alloc(size, flags) \
96 static struct lock_class_key __key; \
97 __ring_buffer_alloc((size), (flags), &__key); \
100 int ring_buffer_wait(struct ring_buffer
*buffer
, int cpu
, bool full
);
101 __poll_t
ring_buffer_poll_wait(struct ring_buffer
*buffer
, int cpu
,
102 struct file
*filp
, poll_table
*poll_table
);
105 #define RING_BUFFER_ALL_CPUS -1
107 void ring_buffer_free(struct ring_buffer
*buffer
);
109 int ring_buffer_resize(struct ring_buffer
*buffer
, unsigned long size
, int cpu
);
111 void ring_buffer_change_overwrite(struct ring_buffer
*buffer
, int val
);
113 struct ring_buffer_event
*ring_buffer_lock_reserve(struct ring_buffer
*buffer
,
114 unsigned long length
);
115 int ring_buffer_unlock_commit(struct ring_buffer
*buffer
,
116 struct ring_buffer_event
*event
);
117 int ring_buffer_write(struct ring_buffer
*buffer
,
118 unsigned long length
, void *data
);
120 void ring_buffer_nest_start(struct ring_buffer
*buffer
);
121 void ring_buffer_nest_end(struct ring_buffer
*buffer
);
123 struct ring_buffer_event
*
124 ring_buffer_peek(struct ring_buffer
*buffer
, int cpu
, u64
*ts
,
125 unsigned long *lost_events
);
126 struct ring_buffer_event
*
127 ring_buffer_consume(struct ring_buffer
*buffer
, int cpu
, u64
*ts
,
128 unsigned long *lost_events
);
130 struct ring_buffer_iter
*
131 ring_buffer_read_prepare(struct ring_buffer
*buffer
, int cpu
);
132 void ring_buffer_read_prepare_sync(void);
133 void ring_buffer_read_start(struct ring_buffer_iter
*iter
);
134 void ring_buffer_read_finish(struct ring_buffer_iter
*iter
);
136 struct ring_buffer_event
*
137 ring_buffer_iter_peek(struct ring_buffer_iter
*iter
, u64
*ts
);
138 struct ring_buffer_event
*
139 ring_buffer_read(struct ring_buffer_iter
*iter
, u64
*ts
);
140 void ring_buffer_iter_reset(struct ring_buffer_iter
*iter
);
141 int ring_buffer_iter_empty(struct ring_buffer_iter
*iter
);
143 unsigned long ring_buffer_size(struct ring_buffer
*buffer
, int cpu
);
145 void ring_buffer_reset_cpu(struct ring_buffer
*buffer
, int cpu
);
146 void ring_buffer_reset(struct ring_buffer
*buffer
);
148 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
149 int ring_buffer_swap_cpu(struct ring_buffer
*buffer_a
,
150 struct ring_buffer
*buffer_b
, int cpu
);
153 ring_buffer_swap_cpu(struct ring_buffer
*buffer_a
,
154 struct ring_buffer
*buffer_b
, int cpu
)
160 bool ring_buffer_empty(struct ring_buffer
*buffer
);
161 bool ring_buffer_empty_cpu(struct ring_buffer
*buffer
, int cpu
);
163 void ring_buffer_record_disable(struct ring_buffer
*buffer
);
164 void ring_buffer_record_enable(struct ring_buffer
*buffer
);
165 void ring_buffer_record_off(struct ring_buffer
*buffer
);
166 void ring_buffer_record_on(struct ring_buffer
*buffer
);
167 int ring_buffer_record_is_on(struct ring_buffer
*buffer
);
168 void ring_buffer_record_disable_cpu(struct ring_buffer
*buffer
, int cpu
);
169 void ring_buffer_record_enable_cpu(struct ring_buffer
*buffer
, int cpu
);
171 u64
ring_buffer_oldest_event_ts(struct ring_buffer
*buffer
, int cpu
);
172 unsigned long ring_buffer_bytes_cpu(struct ring_buffer
*buffer
, int cpu
);
173 unsigned long ring_buffer_entries(struct ring_buffer
*buffer
);
174 unsigned long ring_buffer_overruns(struct ring_buffer
*buffer
);
175 unsigned long ring_buffer_entries_cpu(struct ring_buffer
*buffer
, int cpu
);
176 unsigned long ring_buffer_overrun_cpu(struct ring_buffer
*buffer
, int cpu
);
177 unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer
*buffer
, int cpu
);
178 unsigned long ring_buffer_dropped_events_cpu(struct ring_buffer
*buffer
, int cpu
);
179 unsigned long ring_buffer_read_events_cpu(struct ring_buffer
*buffer
, int cpu
);
181 u64
ring_buffer_time_stamp(struct ring_buffer
*buffer
, int cpu
);
182 void ring_buffer_normalize_time_stamp(struct ring_buffer
*buffer
,
184 void ring_buffer_set_clock(struct ring_buffer
*buffer
,
186 void ring_buffer_set_time_stamp_abs(struct ring_buffer
*buffer
, bool abs
);
187 bool ring_buffer_time_stamp_abs(struct ring_buffer
*buffer
);
189 size_t ring_buffer_page_len(void *page
);
192 void *ring_buffer_alloc_read_page(struct ring_buffer
*buffer
, int cpu
);
193 void ring_buffer_free_read_page(struct ring_buffer
*buffer
, int cpu
, void *data
);
194 int ring_buffer_read_page(struct ring_buffer
*buffer
, void **data_page
,
195 size_t len
, int cpu
, int full
);
199 int ring_buffer_print_entry_header(struct trace_seq
*s
);
200 int ring_buffer_print_page_header(struct trace_seq
*s
);
202 enum ring_buffer_flags
{
203 RB_FL_OVERWRITE
= 1 << 0,
206 #ifdef CONFIG_RING_BUFFER
207 int trace_rb_cpu_prepare(unsigned int cpu
, struct hlist_node
*node
);
209 #define trace_rb_cpu_prepare NULL
212 #endif /* _LINUX_RING_BUFFER_H */