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
8 struct ring_buffer;
9 struct ring_buffer_iter;
10
11 /*
12 * Don't refer to this struct directly, use functions below.
13 */
14 struct ring_buffer_event {
15 kmemcheck_bitfield_begin(bitfield);
16 u32 type_len:5, time_delta:27;
17 kmemcheck_bitfield_end(bitfield);
18
19 u32 array[];
20 };
21
22 /**
23 * enum ring_buffer_type - internal ring buffer types
24 *
25 * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event
26 * If time_delta is 0:
27 * array is ignored
28 * size is variable depending on how much
29 * padding is needed
30 * If time_delta is non zero:
31 * array[0] holds the actual length
32 * size = 4 + length (bytes)
33 *
34 * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
35 * array[0] = time delta (28 .. 59)
36 * size = 8 bytes
37 *
38 * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock
39 * array[0] = tv_nsec
40 * array[1..2] = tv_sec
41 * size = 16 bytes
42 *
43 * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
44 * Data record
45 * If type_len is zero:
46 * array[0] holds the actual length
47 * array[1..(length+3)/4] holds data
48 * size = 4 + length (bytes)
49 * else
50 * length = type_len << 2
51 * array[0..(length+3)/4-1] holds data
52 * size = 4 + length (bytes)
53 */
54 enum ring_buffer_type {
55 RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
56 RINGBUF_TYPE_PADDING,
57 RINGBUF_TYPE_TIME_EXTEND,
58 /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
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
65 /*
66 * ring_buffer_discard_commit will remove an event that has not
67 * ben committed yet. If this is used, then ring_buffer_unlock_commit
68 * must not be called on the discarded event. This function
69 * will try to remove the event from the ring buffer completely
70 * if another event has not been written after it.
71 *
72 * Example use:
73 *
74 * if (some_condition)
75 * ring_buffer_discard_commit(buffer, event);
76 * else
77 * ring_buffer_unlock_commit(buffer, event);
78 */
79 void ring_buffer_discard_commit(struct ring_buffer *buffer,
80 struct ring_buffer_event *event);
81
82 /*
83 * size is in bytes for each per CPU buffer.
84 */
85 struct ring_buffer *
86 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
87
88 /*
89 * Because the ring buffer is generic, if other users of the ring buffer get
90 * traced by ftrace, it can produce lockdep warnings. We need to keep each
91 * ring buffer's lock class separate.
92 */
93 #define ring_buffer_alloc(size, flags) \
94 ({ \
95 static struct lock_class_key __key; \
96 __ring_buffer_alloc((size), (flags), &__key); \
97 })
98
99 void ring_buffer_free(struct ring_buffer *buffer);
100
101 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
102
103 void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val);
104
105 struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
106 unsigned long length);
107 int ring_buffer_unlock_commit(struct ring_buffer *buffer,
108 struct ring_buffer_event *event);
109 int ring_buffer_write(struct ring_buffer *buffer,
110 unsigned long length, void *data);
111
112 struct ring_buffer_event *
113 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
114 unsigned long *lost_events);
115 struct ring_buffer_event *
116 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
117 unsigned long *lost_events);
118
119 struct ring_buffer_iter *
120 ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu);
121 void ring_buffer_read_prepare_sync(void);
122 void ring_buffer_read_start(struct ring_buffer_iter *iter);
123 void ring_buffer_read_finish(struct ring_buffer_iter *iter);
124
125 struct ring_buffer_event *
126 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
127 struct ring_buffer_event *
128 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
129 void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
130 int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
131
132 unsigned long ring_buffer_size(struct ring_buffer *buffer);
133
134 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
135 void ring_buffer_reset(struct ring_buffer *buffer);
136
137 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
138 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
139 struct ring_buffer *buffer_b, int cpu);
140 #else
141 static inline int
ring_buffer_swap_cpu(struct ring_buffer * buffer_a,struct ring_buffer * buffer_b,int cpu)142 ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
143 struct ring_buffer *buffer_b, int cpu)
144 {
145 return -ENODEV;
146 }
147 #endif
148
149 int ring_buffer_empty(struct ring_buffer *buffer);
150 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
151
152 void ring_buffer_record_disable(struct ring_buffer *buffer);
153 void ring_buffer_record_enable(struct ring_buffer *buffer);
154 void ring_buffer_record_off(struct ring_buffer *buffer);
155 void ring_buffer_record_on(struct ring_buffer *buffer);
156 int ring_buffer_record_is_on(struct ring_buffer *buffer);
157 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
158 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
159
160 unsigned long ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu);
161 unsigned long ring_buffer_bytes_cpu(struct ring_buffer *buffer, int cpu);
162 unsigned long ring_buffer_entries(struct ring_buffer *buffer);
163 unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
164 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
165 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
166 unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
167
168 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
169 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
170 int cpu, u64 *ts);
171 void ring_buffer_set_clock(struct ring_buffer *buffer,
172 u64 (*clock)(void));
173
174 size_t ring_buffer_page_len(void *page);
175
176
177 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu);
178 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
179 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
180 size_t len, int cpu, int full);
181
182 struct trace_seq;
183
184 int ring_buffer_print_entry_header(struct trace_seq *s);
185 int ring_buffer_print_page_header(struct trace_seq *s);
186
187 enum ring_buffer_flags {
188 RB_FL_OVERWRITE = 1 << 0,
189 };
190
191 #endif /* _LINUX_RING_BUFFER_H */
192