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 #include <linux/poll.h>
8
9 struct ring_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 kmemcheck_bitfield_begin(bitfield);
17 u32 type_len:5, time_delta:27;
18 kmemcheck_bitfield_end(bitfield);
19
20 u32 array[];
21 };
22
23 /**
24 * enum ring_buffer_type - internal ring buffer types
25 *
26 * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event
27 * If time_delta is 0:
28 * array is ignored
29 * size is variable depending on how much
30 * padding is needed
31 * If time_delta is non zero:
32 * array[0] holds the actual length
33 * size = 4 + length (bytes)
34 *
35 * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
36 * array[0] = time delta (28 .. 59)
37 * size = 8 bytes
38 *
39 * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock
40 * array[0] = tv_nsec
41 * array[1..2] = tv_sec
42 * size = 16 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 /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
60 RINGBUF_TYPE_TIME_STAMP,
61 };
62
63 unsigned ring_buffer_event_length(struct ring_buffer_event *event);
64 void *ring_buffer_event_data(struct ring_buffer_event *event);
65
66 /*
67 * ring_buffer_discard_commit will remove an event that has not
68 * ben 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.
72 *
73 * Example use:
74 *
75 * if (some_condition)
76 * ring_buffer_discard_commit(buffer, event);
77 * else
78 * ring_buffer_unlock_commit(buffer, event);
79 */
80 void ring_buffer_discard_commit(struct ring_buffer *buffer,
81 struct ring_buffer_event *event);
82
83 /*
84 * size is in bytes for each per CPU buffer.
85 */
86 struct ring_buffer *
87 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
88
89 /*
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.
93 */
94 #define ring_buffer_alloc(size, flags) \
95 ({ \
96 static struct lock_class_key __key; \
97 __ring_buffer_alloc((size), (flags), &__key); \
98 })
99
100 int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full);
101 int ring_buffer_poll_wait(struct ring_buffer *buffer, int cpu,
102 struct file *filp, poll_table *poll_table);
103
104
105 #define RING_BUFFER_ALL_CPUS -1
106
107 void ring_buffer_free(struct ring_buffer *buffer);
108
109 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, int cpu);
110
111 void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val);
112
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);
119
120 struct ring_buffer_event *
121 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
122 unsigned long *lost_events);
123 struct ring_buffer_event *
124 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
125 unsigned long *lost_events);
126
127 struct ring_buffer_iter *
128 ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu);
129 void ring_buffer_read_prepare_sync(void);
130 void ring_buffer_read_start(struct ring_buffer_iter *iter);
131 void ring_buffer_read_finish(struct ring_buffer_iter *iter);
132
133 struct ring_buffer_event *
134 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
135 struct ring_buffer_event *
136 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
137 void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
138 int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
139
140 unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu);
141
142 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
143 void ring_buffer_reset(struct ring_buffer *buffer);
144
145 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
146 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
147 struct ring_buffer *buffer_b, int cpu);
148 #else
149 static inline int
ring_buffer_swap_cpu(struct ring_buffer * buffer_a,struct ring_buffer * buffer_b,int cpu)150 ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
151 struct ring_buffer *buffer_b, int cpu)
152 {
153 return -ENODEV;
154 }
155 #endif
156
157 int ring_buffer_empty(struct ring_buffer *buffer);
158 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
159
160 void ring_buffer_record_disable(struct ring_buffer *buffer);
161 void ring_buffer_record_enable(struct ring_buffer *buffer);
162 void ring_buffer_record_off(struct ring_buffer *buffer);
163 void ring_buffer_record_on(struct ring_buffer *buffer);
164 int ring_buffer_record_is_on(struct ring_buffer *buffer);
165 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
166 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
167
168 u64 ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu);
169 unsigned long ring_buffer_bytes_cpu(struct ring_buffer *buffer, int cpu);
170 unsigned long ring_buffer_entries(struct ring_buffer *buffer);
171 unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
172 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
173 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
174 unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
175 unsigned long ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu);
176 unsigned long ring_buffer_read_events_cpu(struct ring_buffer *buffer, int cpu);
177
178 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
179 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
180 int cpu, u64 *ts);
181 void ring_buffer_set_clock(struct ring_buffer *buffer,
182 u64 (*clock)(void));
183
184 size_t ring_buffer_page_len(void *page);
185
186
187 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu);
188 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
189 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
190 size_t len, int cpu, int full);
191
192 struct trace_seq;
193
194 int ring_buffer_print_entry_header(struct trace_seq *s);
195 int ring_buffer_print_page_header(struct trace_seq *s);
196
197 enum ring_buffer_flags {
198 RB_FL_OVERWRITE = 1 << 0,
199 };
200
201 #endif /* _LINUX_RING_BUFFER_H */
202