Linux kernel mirror (for testing)
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linux
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#include <uapi/linux/trace_mmap.h>
10
11struct trace_buffer;
12struct ring_buffer_iter;
13
14/*
15 * Don't refer to this struct directly, use functions below.
16 */
17struct ring_buffer_event {
18 u32 type_len:5, time_delta:27;
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: Absolute timestamp
40 * Same format as TIME_EXTEND except that the
41 * value is an absolute timestamp, not a delta
42 * event.time_delta contains bottom 27 bits
43 * array[0] = top (28 .. 59) bits
44 * size = 8 bytes
45 *
46 * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
47 * Data record
48 * If type_len is zero:
49 * array[0] holds the actual length
50 * array[1..(length+3)/4] holds data
51 * size = 4 + length (bytes)
52 * else
53 * length = type_len << 2
54 * array[0..(length+3)/4-1] holds data
55 * size = 4 + length (bytes)
56 */
57enum ring_buffer_type {
58 RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
59 RINGBUF_TYPE_PADDING,
60 RINGBUF_TYPE_TIME_EXTEND,
61 RINGBUF_TYPE_TIME_STAMP,
62};
63
64unsigned ring_buffer_event_length(struct ring_buffer_event *event);
65void *ring_buffer_event_data(struct ring_buffer_event *event);
66u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer,
67 struct ring_buffer_event *event);
68
69/*
70 * ring_buffer_discard_commit will remove an event that has not
71 * been committed yet. If this is used, then ring_buffer_unlock_commit
72 * must not be called on the discarded event. This function
73 * will try to remove the event from the ring buffer completely
74 * if another event has not been written after it.
75 *
76 * Example use:
77 *
78 * if (some_condition)
79 * ring_buffer_discard_commit(buffer, event);
80 * else
81 * ring_buffer_unlock_commit(buffer, event);
82 */
83void ring_buffer_discard_commit(struct trace_buffer *buffer,
84 struct ring_buffer_event *event);
85
86/*
87 * size is in bytes for each per CPU buffer.
88 */
89struct trace_buffer *
90__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
91
92struct trace_buffer *__ring_buffer_alloc_range(unsigned long size, unsigned flags,
93 int order, unsigned long start,
94 unsigned long range_size,
95 unsigned long scratch_size,
96 struct lock_class_key *key);
97
98void *ring_buffer_meta_scratch(struct trace_buffer *buffer, unsigned int *size);
99
100/*
101 * Because the ring buffer is generic, if other users of the ring buffer get
102 * traced by ftrace, it can produce lockdep warnings. We need to keep each
103 * ring buffer's lock class separate.
104 */
105#define ring_buffer_alloc(size, flags) \
106({ \
107 static struct lock_class_key __key; \
108 __ring_buffer_alloc((size), (flags), &__key); \
109})
110
111/*
112 * Because the ring buffer is generic, if other users of the ring buffer get
113 * traced by ftrace, it can produce lockdep warnings. We need to keep each
114 * ring buffer's lock class separate.
115 */
116#define ring_buffer_alloc_range(size, flags, order, start, range_size, s_size) \
117({ \
118 static struct lock_class_key __key; \
119 __ring_buffer_alloc_range((size), (flags), (order), (start), \
120 (range_size), (s_size), &__key); \
121})
122
123typedef bool (*ring_buffer_cond_fn)(void *data);
124int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full,
125 ring_buffer_cond_fn cond, void *data);
126__poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu,
127 struct file *filp, poll_table *poll_table, int full);
128void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu);
129
130#define RING_BUFFER_ALL_CPUS -1
131
132void ring_buffer_free(struct trace_buffer *buffer);
133
134int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu);
135
136void ring_buffer_change_overwrite(struct trace_buffer *buffer, int val);
137
138struct ring_buffer_event *ring_buffer_lock_reserve(struct trace_buffer *buffer,
139 unsigned long length);
140int ring_buffer_unlock_commit(struct trace_buffer *buffer);
141int ring_buffer_write(struct trace_buffer *buffer,
142 unsigned long length, void *data);
143
144void ring_buffer_nest_start(struct trace_buffer *buffer);
145void ring_buffer_nest_end(struct trace_buffer *buffer);
146
147DEFINE_GUARD(ring_buffer_nest, struct trace_buffer *,
148 ring_buffer_nest_start(_T), ring_buffer_nest_end(_T))
149
150struct ring_buffer_event *
151ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts,
152 unsigned long *lost_events);
153struct ring_buffer_event *
154ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts,
155 unsigned long *lost_events);
156
157struct ring_buffer_iter *
158ring_buffer_read_start(struct trace_buffer *buffer, int cpu, gfp_t flags);
159void ring_buffer_read_finish(struct ring_buffer_iter *iter);
160
161struct ring_buffer_event *
162ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
163void ring_buffer_iter_advance(struct ring_buffer_iter *iter);
164void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
165int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
166bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter);
167
168unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu);
169unsigned long ring_buffer_max_event_size(struct trace_buffer *buffer);
170
171void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu);
172void ring_buffer_reset_online_cpus(struct trace_buffer *buffer);
173void ring_buffer_reset(struct trace_buffer *buffer);
174
175#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
176int ring_buffer_swap_cpu(struct trace_buffer *buffer_a,
177 struct trace_buffer *buffer_b, int cpu);
178#else
179static inline int
180ring_buffer_swap_cpu(struct trace_buffer *buffer_a,
181 struct trace_buffer *buffer_b, int cpu)
182{
183 return -ENODEV;
184}
185#endif
186
187bool ring_buffer_empty(struct trace_buffer *buffer);
188bool ring_buffer_empty_cpu(struct trace_buffer *buffer, int cpu);
189
190void ring_buffer_record_disable(struct trace_buffer *buffer);
191void ring_buffer_record_enable(struct trace_buffer *buffer);
192void ring_buffer_record_off(struct trace_buffer *buffer);
193void ring_buffer_record_on(struct trace_buffer *buffer);
194bool ring_buffer_record_is_on(struct trace_buffer *buffer);
195bool ring_buffer_record_is_set_on(struct trace_buffer *buffer);
196bool ring_buffer_record_is_on_cpu(struct trace_buffer *buffer, int cpu);
197void ring_buffer_record_disable_cpu(struct trace_buffer *buffer, int cpu);
198void ring_buffer_record_enable_cpu(struct trace_buffer *buffer, int cpu);
199
200u64 ring_buffer_oldest_event_ts(struct trace_buffer *buffer, int cpu);
201unsigned long ring_buffer_bytes_cpu(struct trace_buffer *buffer, int cpu);
202unsigned long ring_buffer_entries(struct trace_buffer *buffer);
203unsigned long ring_buffer_overruns(struct trace_buffer *buffer);
204unsigned long ring_buffer_entries_cpu(struct trace_buffer *buffer, int cpu);
205unsigned long ring_buffer_overrun_cpu(struct trace_buffer *buffer, int cpu);
206unsigned long ring_buffer_commit_overrun_cpu(struct trace_buffer *buffer, int cpu);
207unsigned long ring_buffer_dropped_events_cpu(struct trace_buffer *buffer, int cpu);
208unsigned long ring_buffer_read_events_cpu(struct trace_buffer *buffer, int cpu);
209
210u64 ring_buffer_time_stamp(struct trace_buffer *buffer);
211void ring_buffer_normalize_time_stamp(struct trace_buffer *buffer,
212 int cpu, u64 *ts);
213void ring_buffer_set_clock(struct trace_buffer *buffer,
214 u64 (*clock)(void));
215void ring_buffer_set_time_stamp_abs(struct trace_buffer *buffer, bool abs);
216bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer);
217
218size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu);
219
220struct buffer_data_read_page;
221struct buffer_data_read_page *
222ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu);
223void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu,
224 struct buffer_data_read_page *page);
225int ring_buffer_read_page(struct trace_buffer *buffer,
226 struct buffer_data_read_page *data_page,
227 size_t len, int cpu, int full);
228void *ring_buffer_read_page_data(struct buffer_data_read_page *page);
229
230struct trace_seq;
231
232int ring_buffer_print_entry_header(struct trace_seq *s);
233int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s);
234
235int ring_buffer_subbuf_order_get(struct trace_buffer *buffer);
236int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order);
237int ring_buffer_subbuf_size_get(struct trace_buffer *buffer);
238
239enum ring_buffer_flags {
240 RB_FL_OVERWRITE = 1 << 0,
241};
242
243#ifdef CONFIG_RING_BUFFER
244int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node);
245#else
246#define trace_rb_cpu_prepare NULL
247#endif
248
249int ring_buffer_map(struct trace_buffer *buffer, int cpu,
250 struct vm_area_struct *vma);
251void ring_buffer_map_dup(struct trace_buffer *buffer, int cpu);
252int ring_buffer_unmap(struct trace_buffer *buffer, int cpu);
253int ring_buffer_map_get_reader(struct trace_buffer *buffer, int cpu);
254
255struct ring_buffer_desc {
256 int cpu;
257 unsigned int nr_page_va; /* excludes the meta page */
258 unsigned long meta_va;
259 unsigned long page_va[] __counted_by(nr_page_va);
260};
261
262struct trace_buffer_desc {
263 int nr_cpus;
264 size_t struct_len;
265 char __data[]; /* list of ring_buffer_desc */
266};
267
268static inline struct ring_buffer_desc *__next_ring_buffer_desc(struct ring_buffer_desc *desc)
269{
270 size_t len = struct_size(desc, page_va, desc->nr_page_va);
271
272 return (struct ring_buffer_desc *)((void *)desc + len);
273}
274
275static inline struct ring_buffer_desc *__first_ring_buffer_desc(struct trace_buffer_desc *desc)
276{
277 return (struct ring_buffer_desc *)(&desc->__data[0]);
278}
279
280static inline size_t trace_buffer_desc_size(size_t buffer_size, unsigned int nr_cpus)
281{
282 unsigned int nr_pages = max(DIV_ROUND_UP(buffer_size, PAGE_SIZE), 2UL) + 1;
283 struct ring_buffer_desc *rbdesc;
284
285 return size_add(offsetof(struct trace_buffer_desc, __data),
286 size_mul(nr_cpus, struct_size(rbdesc, page_va, nr_pages)));
287}
288
289#define for_each_ring_buffer_desc(__pdesc, __cpu, __trace_pdesc) \
290 for (__pdesc = __first_ring_buffer_desc(__trace_pdesc), __cpu = 0; \
291 (__cpu) < (__trace_pdesc)->nr_cpus; \
292 (__cpu)++, __pdesc = __next_ring_buffer_desc(__pdesc))
293
294struct ring_buffer_remote {
295 struct trace_buffer_desc *desc;
296 int (*swap_reader_page)(unsigned int cpu, void *priv);
297 int (*reset)(unsigned int cpu, void *priv);
298 void *priv;
299};
300
301int ring_buffer_poll_remote(struct trace_buffer *buffer, int cpu);
302
303struct trace_buffer *
304__ring_buffer_alloc_remote(struct ring_buffer_remote *remote,
305 struct lock_class_key *key);
306
307#define ring_buffer_alloc_remote(remote) \
308({ \
309 static struct lock_class_key __key; \
310 __ring_buffer_alloc_remote(remote, &__key); \
311})
312#endif /* _LINUX_RING_BUFFER_H */