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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 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 | 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: Sync time stamp with external clock | |
38 | * array[0] = tv_nsec | |
39 | * array[1..2] = tv_sec | |
40 | * size = 16 bytes | |
41 | * | |
42 | * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX: | |
43 | * Data record | |
44 | * If type_len is zero: | |
45 | * array[0] holds the actual length | |
46 | * array[1..(length+3)/4] holds data | |
47 | * size = 4 + length (bytes) | |
48 | * else | |
49 | * length = type_len << 2 | |
50 | * array[0..(length+3)/4-1] holds data | |
51 | * size = 4 + length (bytes) | |
52 | */ | |
53 | enum ring_buffer_type { | |
54 | RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28, | |
55 | RINGBUF_TYPE_PADDING, | |
56 | RINGBUF_TYPE_TIME_EXTEND, | |
57 | /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */ | |
58 | RINGBUF_TYPE_TIME_STAMP, | |
59 | }; | |
60 | ||
61 | unsigned ring_buffer_event_length(struct ring_buffer_event *event); | |
62 | void *ring_buffer_event_data(struct ring_buffer_event *event); | |
63 | ||
64 | /* | |
65 | * ring_buffer_discard_commit will remove an event that has not | |
66 | * ben committed yet. If this is used, then ring_buffer_unlock_commit | |
67 | * must not be called on the discarded event. This function | |
68 | * will try to remove the event from the ring buffer completely | |
69 | * if another event has not been written after it. | |
70 | * | |
71 | * Example use: | |
72 | * | |
73 | * if (some_condition) | |
74 | * ring_buffer_discard_commit(buffer, event); | |
75 | * else | |
76 | * ring_buffer_unlock_commit(buffer, event); | |
77 | */ | |
78 | void ring_buffer_discard_commit(struct ring_buffer *buffer, | |
79 | struct ring_buffer_event *event); | |
80 | ||
81 | /* | |
82 | * size is in bytes for each per CPU buffer. | |
83 | */ | |
84 | struct ring_buffer * | |
85 | __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key); | |
86 | ||
87 | /* | |
88 | * Because the ring buffer is generic, if other users of the ring buffer get | |
89 | * traced by ftrace, it can produce lockdep warnings. We need to keep each | |
90 | * ring buffer's lock class separate. | |
91 | */ | |
92 | #define ring_buffer_alloc(size, flags) \ | |
93 | ({ \ | |
94 | static struct lock_class_key __key; \ | |
95 | __ring_buffer_alloc((size), (flags), &__key); \ | |
96 | }) | |
97 | ||
98 | int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full); | |
99 | int ring_buffer_poll_wait(struct ring_buffer *buffer, int cpu, | |
100 | struct file *filp, poll_table *poll_table); | |
101 | ||
102 | ||
103 | #define RING_BUFFER_ALL_CPUS -1 | |
104 | ||
105 | void ring_buffer_free(struct ring_buffer *buffer); | |
106 | ||
107 | int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, int cpu); | |
108 | ||
109 | void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val); | |
110 | ||
111 | struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer, | |
112 | unsigned long length); | |
113 | int ring_buffer_unlock_commit(struct ring_buffer *buffer, | |
114 | struct ring_buffer_event *event); | |
115 | int ring_buffer_write(struct ring_buffer *buffer, | |
116 | unsigned long length, void *data); | |
117 | ||
118 | struct ring_buffer_event * | |
119 | ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts, | |
120 | unsigned long *lost_events); | |
121 | struct ring_buffer_event * | |
122 | ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts, | |
123 | unsigned long *lost_events); | |
124 | ||
125 | struct ring_buffer_iter * | |
126 | ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu, gfp_t flags); | |
127 | void ring_buffer_read_prepare_sync(void); | |
128 | void ring_buffer_read_start(struct ring_buffer_iter *iter); | |
129 | void ring_buffer_read_finish(struct ring_buffer_iter *iter); | |
130 | ||
131 | struct ring_buffer_event * | |
132 | ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); | |
133 | struct ring_buffer_event * | |
134 | ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts); | |
135 | void ring_buffer_iter_reset(struct ring_buffer_iter *iter); | |
136 | int ring_buffer_iter_empty(struct ring_buffer_iter *iter); | |
137 | ||
138 | unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu); | |
139 | ||
140 | void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu); | |
141 | void ring_buffer_reset(struct ring_buffer *buffer); | |
142 | ||
143 | #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP | |
144 | int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, | |
145 | struct ring_buffer *buffer_b, int cpu); | |
146 | #else | |
147 | static inline int | |
148 | ring_buffer_swap_cpu(struct ring_buffer *buffer_a, | |
149 | struct ring_buffer *buffer_b, int cpu) | |
150 | { | |
151 | return -ENODEV; | |
152 | } | |
153 | #endif | |
154 | ||
155 | bool ring_buffer_empty(struct ring_buffer *buffer); | |
156 | bool ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu); | |
157 | ||
158 | void ring_buffer_record_disable(struct ring_buffer *buffer); | |
159 | void ring_buffer_record_enable(struct ring_buffer *buffer); | |
160 | void ring_buffer_record_off(struct ring_buffer *buffer); | |
161 | void ring_buffer_record_on(struct ring_buffer *buffer); | |
162 | int ring_buffer_record_is_on(struct ring_buffer *buffer); | |
163 | int ring_buffer_record_is_set_on(struct ring_buffer *buffer); | |
164 | void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu); | |
165 | void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu); | |
166 | ||
167 | u64 ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu); | |
168 | unsigned long ring_buffer_bytes_cpu(struct ring_buffer *buffer, int cpu); | |
169 | unsigned long ring_buffer_entries(struct ring_buffer *buffer); | |
170 | unsigned long ring_buffer_overruns(struct ring_buffer *buffer); | |
171 | unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); | |
172 | unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); | |
173 | unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu); | |
174 | unsigned long ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu); | |
175 | unsigned long ring_buffer_read_events_cpu(struct ring_buffer *buffer, int cpu); | |
176 | ||
177 | u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); | |
178 | void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, | |
179 | int cpu, u64 *ts); | |
180 | void ring_buffer_set_clock(struct ring_buffer *buffer, | |
181 | u64 (*clock)(void)); | |
182 | ||
183 | size_t ring_buffer_page_len(void *page); | |
184 | ||
185 | ||
186 | void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu); | |
187 | void ring_buffer_free_read_page(struct ring_buffer *buffer, int cpu, void *data); | |
188 | int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page, | |
189 | size_t len, int cpu, int full); | |
190 | ||
191 | struct trace_seq; | |
192 | ||
193 | int ring_buffer_print_entry_header(struct trace_seq *s); | |
194 | int ring_buffer_print_page_header(struct trace_seq *s); | |
195 | ||
196 | enum ring_buffer_flags { | |
197 | RB_FL_OVERWRITE = 1 << 0, | |
198 | }; | |
199 | ||
200 | #ifdef CONFIG_RING_BUFFER | |
201 | int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node); | |
202 | #else | |
203 | #define trace_rb_cpu_prepare NULL | |
204 | #endif | |
205 | ||
206 | #endif /* _LINUX_RING_BUFFER_H */ |