17a8e76a3SSteven Rostedt #ifndef _LINUX_RING_BUFFER_H 27a8e76a3SSteven Rostedt #define _LINUX_RING_BUFFER_H 37a8e76a3SSteven Rostedt 4*1744a21dSVegard Nossum #include <linux/kmemcheck.h> 57a8e76a3SSteven Rostedt #include <linux/mm.h> 67a8e76a3SSteven Rostedt #include <linux/seq_file.h> 77a8e76a3SSteven Rostedt 87a8e76a3SSteven Rostedt struct ring_buffer; 97a8e76a3SSteven Rostedt struct ring_buffer_iter; 107a8e76a3SSteven Rostedt 117a8e76a3SSteven Rostedt /* 12c3706f00SWenji Huang * Don't refer to this struct directly, use functions below. 137a8e76a3SSteven Rostedt */ 147a8e76a3SSteven Rostedt struct ring_buffer_event { 15*1744a21dSVegard Nossum kmemcheck_bitfield_begin(bitfield); 16334d4169SLai Jiangshan u32 type_len:5, time_delta:27; 17*1744a21dSVegard Nossum kmemcheck_bitfield_end(bitfield); 18*1744a21dSVegard Nossum 197a8e76a3SSteven Rostedt u32 array[]; 207a8e76a3SSteven Rostedt }; 217a8e76a3SSteven Rostedt 227a8e76a3SSteven Rostedt /** 237a8e76a3SSteven Rostedt * enum ring_buffer_type - internal ring buffer types 247a8e76a3SSteven Rostedt * 252d622719STom Zanussi * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event 262d622719STom Zanussi * If time_delta is 0: 277a8e76a3SSteven Rostedt * array is ignored 287a8e76a3SSteven Rostedt * size is variable depending on how much 297a8e76a3SSteven Rostedt * padding is needed 302d622719STom Zanussi * If time_delta is non zero: 31334d4169SLai Jiangshan * array[0] holds the actual length 32334d4169SLai Jiangshan * size = 4 + length (bytes) 337a8e76a3SSteven Rostedt * 347a8e76a3SSteven Rostedt * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta 357a8e76a3SSteven Rostedt * array[0] = time delta (28 .. 59) 367a8e76a3SSteven Rostedt * size = 8 bytes 377a8e76a3SSteven Rostedt * 387a8e76a3SSteven Rostedt * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock 397a8e76a3SSteven Rostedt * array[0] = tv_nsec 40361b73d5SLai Jiangshan * array[1..2] = tv_sec 417a8e76a3SSteven Rostedt * size = 16 bytes 427a8e76a3SSteven Rostedt * 43334d4169SLai Jiangshan * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX: 44334d4169SLai Jiangshan * Data record 45334d4169SLai Jiangshan * If type_len is zero: 467a8e76a3SSteven Rostedt * array[0] holds the actual length 47361b73d5SLai Jiangshan * array[1..(length+3)/4] holds data 48334d4169SLai Jiangshan * size = 4 + length (bytes) 497a8e76a3SSteven Rostedt * else 50334d4169SLai Jiangshan * length = type_len << 2 51361b73d5SLai Jiangshan * array[0..(length+3)/4-1] holds data 52361b73d5SLai Jiangshan * size = 4 + length (bytes) 537a8e76a3SSteven Rostedt */ 547a8e76a3SSteven Rostedt enum ring_buffer_type { 55334d4169SLai Jiangshan RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28, 567a8e76a3SSteven Rostedt RINGBUF_TYPE_PADDING, 577a8e76a3SSteven Rostedt RINGBUF_TYPE_TIME_EXTEND, 587a8e76a3SSteven Rostedt /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */ 597a8e76a3SSteven Rostedt RINGBUF_TYPE_TIME_STAMP, 607a8e76a3SSteven Rostedt }; 617a8e76a3SSteven Rostedt 627a8e76a3SSteven Rostedt unsigned ring_buffer_event_length(struct ring_buffer_event *event); 637a8e76a3SSteven Rostedt void *ring_buffer_event_data(struct ring_buffer_event *event); 647a8e76a3SSteven Rostedt 657a8e76a3SSteven Rostedt /** 667a8e76a3SSteven Rostedt * ring_buffer_event_time_delta - return the delta timestamp of the event 677a8e76a3SSteven Rostedt * @event: the event to get the delta timestamp of 687a8e76a3SSteven Rostedt * 697a8e76a3SSteven Rostedt * The delta timestamp is the 27 bit timestamp since the last event. 707a8e76a3SSteven Rostedt */ 717a8e76a3SSteven Rostedt static inline unsigned 727a8e76a3SSteven Rostedt ring_buffer_event_time_delta(struct ring_buffer_event *event) 737a8e76a3SSteven Rostedt { 747a8e76a3SSteven Rostedt return event->time_delta; 757a8e76a3SSteven Rostedt } 767a8e76a3SSteven Rostedt 77fa1b47ddSSteven Rostedt /* 78fa1b47ddSSteven Rostedt * ring_buffer_event_discard can discard any event in the ring buffer. 79fa1b47ddSSteven Rostedt * it is up to the caller to protect against a reader from 80fa1b47ddSSteven Rostedt * consuming it or a writer from wrapping and replacing it. 81fa1b47ddSSteven Rostedt * 82fa1b47ddSSteven Rostedt * No external protection is needed if this is called before 83fa1b47ddSSteven Rostedt * the event is commited. But in that case it would be better to 84fa1b47ddSSteven Rostedt * use ring_buffer_discard_commit. 85fa1b47ddSSteven Rostedt * 86fa1b47ddSSteven Rostedt * Note, if an event that has not been committed is discarded 87fa1b47ddSSteven Rostedt * with ring_buffer_event_discard, it must still be committed. 88fa1b47ddSSteven Rostedt */ 892d622719STom Zanussi void ring_buffer_event_discard(struct ring_buffer_event *event); 902d622719STom Zanussi 917a8e76a3SSteven Rostedt /* 92fa1b47ddSSteven Rostedt * ring_buffer_discard_commit will remove an event that has not 93fa1b47ddSSteven Rostedt * ben committed yet. If this is used, then ring_buffer_unlock_commit 94fa1b47ddSSteven Rostedt * must not be called on the discarded event. This function 95fa1b47ddSSteven Rostedt * will try to remove the event from the ring buffer completely 96fa1b47ddSSteven Rostedt * if another event has not been written after it. 97fa1b47ddSSteven Rostedt * 98fa1b47ddSSteven Rostedt * Example use: 99fa1b47ddSSteven Rostedt * 100fa1b47ddSSteven Rostedt * if (some_condition) 101fa1b47ddSSteven Rostedt * ring_buffer_discard_commit(buffer, event); 102fa1b47ddSSteven Rostedt * else 103fa1b47ddSSteven Rostedt * ring_buffer_unlock_commit(buffer, event); 104fa1b47ddSSteven Rostedt */ 105fa1b47ddSSteven Rostedt void ring_buffer_discard_commit(struct ring_buffer *buffer, 106fa1b47ddSSteven Rostedt struct ring_buffer_event *event); 107fa1b47ddSSteven Rostedt 108fa1b47ddSSteven Rostedt /* 1097a8e76a3SSteven Rostedt * size is in bytes for each per CPU buffer. 1107a8e76a3SSteven Rostedt */ 1117a8e76a3SSteven Rostedt struct ring_buffer * 1121f8a6a10SPeter Zijlstra __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key); 1131f8a6a10SPeter Zijlstra 1141f8a6a10SPeter Zijlstra /* 1151f8a6a10SPeter Zijlstra * Because the ring buffer is generic, if other users of the ring buffer get 1161f8a6a10SPeter Zijlstra * traced by ftrace, it can produce lockdep warnings. We need to keep each 1171f8a6a10SPeter Zijlstra * ring buffer's lock class separate. 1181f8a6a10SPeter Zijlstra */ 1191f8a6a10SPeter Zijlstra #define ring_buffer_alloc(size, flags) \ 1201f8a6a10SPeter Zijlstra ({ \ 1211f8a6a10SPeter Zijlstra static struct lock_class_key __key; \ 1221f8a6a10SPeter Zijlstra __ring_buffer_alloc((size), (flags), &__key); \ 1231f8a6a10SPeter Zijlstra }) 1241f8a6a10SPeter Zijlstra 1257a8e76a3SSteven Rostedt void ring_buffer_free(struct ring_buffer *buffer); 1267a8e76a3SSteven Rostedt 1277a8e76a3SSteven Rostedt int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size); 1287a8e76a3SSteven Rostedt 1290a987751SArnaldo Carvalho de Melo struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer, 1300a987751SArnaldo Carvalho de Melo unsigned long length); 1317a8e76a3SSteven Rostedt int ring_buffer_unlock_commit(struct ring_buffer *buffer, 1320a987751SArnaldo Carvalho de Melo struct ring_buffer_event *event); 1337a8e76a3SSteven Rostedt int ring_buffer_write(struct ring_buffer *buffer, 1347a8e76a3SSteven Rostedt unsigned long length, void *data); 1357a8e76a3SSteven Rostedt 1367a8e76a3SSteven Rostedt struct ring_buffer_event * 1377a8e76a3SSteven Rostedt ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts); 1387a8e76a3SSteven Rostedt struct ring_buffer_event * 1397a8e76a3SSteven Rostedt ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts); 1407a8e76a3SSteven Rostedt 1417a8e76a3SSteven Rostedt struct ring_buffer_iter * 1427a8e76a3SSteven Rostedt ring_buffer_read_start(struct ring_buffer *buffer, int cpu); 1437a8e76a3SSteven Rostedt void ring_buffer_read_finish(struct ring_buffer_iter *iter); 1447a8e76a3SSteven Rostedt 1457a8e76a3SSteven Rostedt struct ring_buffer_event * 1467a8e76a3SSteven Rostedt ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); 1477a8e76a3SSteven Rostedt struct ring_buffer_event * 1487a8e76a3SSteven Rostedt ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts); 1497a8e76a3SSteven Rostedt void ring_buffer_iter_reset(struct ring_buffer_iter *iter); 1507a8e76a3SSteven Rostedt int ring_buffer_iter_empty(struct ring_buffer_iter *iter); 1517a8e76a3SSteven Rostedt 1527a8e76a3SSteven Rostedt unsigned long ring_buffer_size(struct ring_buffer *buffer); 1537a8e76a3SSteven Rostedt 1547a8e76a3SSteven Rostedt void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu); 1557a8e76a3SSteven Rostedt void ring_buffer_reset(struct ring_buffer *buffer); 1567a8e76a3SSteven Rostedt 1577a8e76a3SSteven Rostedt int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 1587a8e76a3SSteven Rostedt struct ring_buffer *buffer_b, int cpu); 1597a8e76a3SSteven Rostedt 1607a8e76a3SSteven Rostedt int ring_buffer_empty(struct ring_buffer *buffer); 1617a8e76a3SSteven Rostedt int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu); 1627a8e76a3SSteven Rostedt 1637a8e76a3SSteven Rostedt void ring_buffer_record_disable(struct ring_buffer *buffer); 1647a8e76a3SSteven Rostedt void ring_buffer_record_enable(struct ring_buffer *buffer); 1657a8e76a3SSteven Rostedt void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu); 1667a8e76a3SSteven Rostedt void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu); 1677a8e76a3SSteven Rostedt 1687a8e76a3SSteven Rostedt unsigned long ring_buffer_entries(struct ring_buffer *buffer); 1697a8e76a3SSteven Rostedt unsigned long ring_buffer_overruns(struct ring_buffer *buffer); 170e09373f2SRobert Richter unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); 171e09373f2SRobert Richter unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); 172f0d2c681SSteven Rostedt unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu); 173f0d2c681SSteven Rostedt unsigned long ring_buffer_nmi_dropped_cpu(struct ring_buffer *buffer, int cpu); 1747a8e76a3SSteven Rostedt 17537886f6aSSteven Rostedt u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); 17637886f6aSSteven Rostedt void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, 17737886f6aSSteven Rostedt int cpu, u64 *ts); 17837886f6aSSteven Rostedt void ring_buffer_set_clock(struct ring_buffer *buffer, 17937886f6aSSteven Rostedt u64 (*clock)(void)); 1807a8e76a3SSteven Rostedt 181ef7a4a16SSteven Rostedt size_t ring_buffer_page_len(void *page); 182ef7a4a16SSteven Rostedt 183ef7a4a16SSteven Rostedt 1848789a9e7SSteven Rostedt void *ring_buffer_alloc_read_page(struct ring_buffer *buffer); 1858789a9e7SSteven Rostedt void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data); 186ef7a4a16SSteven Rostedt int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page, 187ef7a4a16SSteven Rostedt size_t len, int cpu, int full); 1888789a9e7SSteven Rostedt 189d1b182a8SSteven Rostedt struct trace_seq; 190d1b182a8SSteven Rostedt 191d1b182a8SSteven Rostedt int ring_buffer_print_entry_header(struct trace_seq *s); 192d1b182a8SSteven Rostedt int ring_buffer_print_page_header(struct trace_seq *s); 193d1b182a8SSteven Rostedt 1947a8e76a3SSteven Rostedt enum ring_buffer_flags { 1957a8e76a3SSteven Rostedt RB_FL_OVERWRITE = 1 << 0, 1967a8e76a3SSteven Rostedt }; 1977a8e76a3SSteven Rostedt 1987a8e76a3SSteven Rostedt #endif /* _LINUX_RING_BUFFER_H */ 199