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 | |
9 | struct trace_buffer; |
10 | struct ring_buffer_iter; |
11 | |
12 | /* |
13 | * Don't refer to this struct directly, use functions below. |
14 | */ |
15 | struct 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 | */ |
55 | enum 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 | |
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); |
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 | */ |
81 | void 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 | */ |
87 | struct 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 | |
101 | int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full); |
102 | __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, |
103 | struct file *filp, poll_table *poll_table, int full); |
104 | void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu); |
105 | |
106 | #define RING_BUFFER_ALL_CPUS -1 |
107 | |
108 | void ring_buffer_free(struct trace_buffer *buffer); |
109 | |
110 | int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu); |
111 | |
112 | void ring_buffer_change_overwrite(struct trace_buffer *buffer, int val); |
113 | |
114 | struct ring_buffer_event *ring_buffer_lock_reserve(struct trace_buffer *buffer, |
115 | unsigned long length); |
116 | int ring_buffer_unlock_commit(struct trace_buffer *buffer); |
117 | int ring_buffer_write(struct trace_buffer *buffer, |
118 | unsigned long length, void *data); |
119 | |
120 | void ring_buffer_nest_start(struct trace_buffer *buffer); |
121 | void ring_buffer_nest_end(struct trace_buffer *buffer); |
122 | |
123 | struct ring_buffer_event * |
124 | ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts, |
125 | unsigned long *lost_events); |
126 | struct ring_buffer_event * |
127 | ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts, |
128 | unsigned long *lost_events); |
129 | |
130 | struct ring_buffer_iter * |
131 | ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags); |
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); |
135 | |
136 | struct ring_buffer_event * |
137 | ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); |
138 | void ring_buffer_iter_advance(struct ring_buffer_iter *iter); |
139 | void ring_buffer_iter_reset(struct ring_buffer_iter *iter); |
140 | int ring_buffer_iter_empty(struct ring_buffer_iter *iter); |
141 | bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter); |
142 | |
143 | unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu); |
144 | |
145 | void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu); |
146 | void ring_buffer_reset_online_cpus(struct trace_buffer *buffer); |
147 | void ring_buffer_reset(struct trace_buffer *buffer); |
148 | |
149 | #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP |
150 | int ring_buffer_swap_cpu(struct trace_buffer *buffer_a, |
151 | struct trace_buffer *buffer_b, int cpu); |
152 | #else |
153 | static inline int |
154 | ring_buffer_swap_cpu(struct trace_buffer *buffer_a, |
155 | struct trace_buffer *buffer_b, int cpu) |
156 | { |
157 | return -ENODEV; |
158 | } |
159 | #endif |
160 | |
161 | bool ring_buffer_empty(struct trace_buffer *buffer); |
162 | bool ring_buffer_empty_cpu(struct trace_buffer *buffer, int cpu); |
163 | |
164 | void ring_buffer_record_disable(struct trace_buffer *buffer); |
165 | void ring_buffer_record_enable(struct trace_buffer *buffer); |
166 | void ring_buffer_record_off(struct trace_buffer *buffer); |
167 | void ring_buffer_record_on(struct trace_buffer *buffer); |
168 | bool ring_buffer_record_is_on(struct trace_buffer *buffer); |
169 | bool ring_buffer_record_is_set_on(struct trace_buffer *buffer); |
170 | void ring_buffer_record_disable_cpu(struct trace_buffer *buffer, int cpu); |
171 | void ring_buffer_record_enable_cpu(struct trace_buffer *buffer, int cpu); |
172 | |
173 | u64 ring_buffer_oldest_event_ts(struct trace_buffer *buffer, int cpu); |
174 | unsigned long ring_buffer_bytes_cpu(struct trace_buffer *buffer, int cpu); |
175 | unsigned long ring_buffer_entries(struct trace_buffer *buffer); |
176 | unsigned long ring_buffer_overruns(struct trace_buffer *buffer); |
177 | unsigned long ring_buffer_entries_cpu(struct trace_buffer *buffer, int cpu); |
178 | unsigned long ring_buffer_overrun_cpu(struct trace_buffer *buffer, int cpu); |
179 | unsigned long ring_buffer_commit_overrun_cpu(struct trace_buffer *buffer, int cpu); |
180 | unsigned long ring_buffer_dropped_events_cpu(struct trace_buffer *buffer, int cpu); |
181 | unsigned long ring_buffer_read_events_cpu(struct trace_buffer *buffer, int cpu); |
182 | |
183 | u64 ring_buffer_time_stamp(struct trace_buffer *buffer); |
184 | void ring_buffer_normalize_time_stamp(struct trace_buffer *buffer, |
185 | int cpu, u64 *ts); |
186 | void ring_buffer_set_clock(struct trace_buffer *buffer, |
187 | u64 (*clock)(void)); |
188 | void ring_buffer_set_time_stamp_abs(struct trace_buffer *buffer, bool abs); |
189 | bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer); |
190 | |
191 | size_t ring_buffer_nr_pages(struct trace_buffer *buffer, int cpu); |
192 | size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu); |
193 | |
194 | void *ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu); |
195 | void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, void *data); |
196 | int ring_buffer_read_page(struct trace_buffer *buffer, void **data_page, |
197 | size_t len, int cpu, int full); |
198 | |
199 | struct trace_seq; |
200 | |
201 | int (struct trace_seq *s); |
202 | int (struct trace_seq *s); |
203 | |
204 | enum ring_buffer_flags { |
205 | RB_FL_OVERWRITE = 1 << 0, |
206 | }; |
207 | |
208 | #ifdef CONFIG_RING_BUFFER |
209 | int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node); |
210 | #else |
211 | #define trace_rb_cpu_prepare NULL |
212 | #endif |
213 | |
214 | #endif /* _LINUX_RING_BUFFER_H */ |
215 | |