| 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 | #define RING_BUFFER_ALL_CPUS -1 |
| 100 | |
| 101 | void ring_buffer_free(struct ring_buffer *buffer); |
| 102 | |
| 103 | int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, int cpu); |
| 104 | |
| 105 | void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val); |
| 106 | |
| 107 | struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer, |
| 108 | unsigned long length); |
| 109 | int ring_buffer_unlock_commit(struct ring_buffer *buffer, |
| 110 | struct ring_buffer_event *event); |
| 111 | int ring_buffer_write(struct ring_buffer *buffer, |
| 112 | unsigned long length, void *data); |
| 113 | |
| 114 | struct ring_buffer_event * |
| 115 | ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts, |
| 116 | unsigned long *lost_events); |
| 117 | struct ring_buffer_event * |
| 118 | ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts, |
| 119 | unsigned long *lost_events); |
| 120 | |
| 121 | struct ring_buffer_iter * |
| 122 | ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu); |
| 123 | void ring_buffer_read_prepare_sync(void); |
| 124 | void ring_buffer_read_start(struct ring_buffer_iter *iter); |
| 125 | void ring_buffer_read_finish(struct ring_buffer_iter *iter); |
| 126 | |
| 127 | struct ring_buffer_event * |
| 128 | ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); |
| 129 | struct ring_buffer_event * |
| 130 | ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts); |
| 131 | void ring_buffer_iter_reset(struct ring_buffer_iter *iter); |
| 132 | int ring_buffer_iter_empty(struct ring_buffer_iter *iter); |
| 133 | |
| 134 | unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu); |
| 135 | |
| 136 | void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu); |
| 137 | void ring_buffer_reset(struct ring_buffer *buffer); |
| 138 | |
| 139 | #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP |
| 140 | int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, |
| 141 | struct ring_buffer *buffer_b, int cpu); |
| 142 | #else |
| 143 | static inline int |
| 144 | ring_buffer_swap_cpu(struct ring_buffer *buffer_a, |
| 145 | struct ring_buffer *buffer_b, int cpu) |
| 146 | { |
| 147 | return -ENODEV; |
| 148 | } |
| 149 | #endif |
| 150 | |
| 151 | int ring_buffer_empty(struct ring_buffer *buffer); |
| 152 | int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu); |
| 153 | |
| 154 | void ring_buffer_record_disable(struct ring_buffer *buffer); |
| 155 | void ring_buffer_record_enable(struct ring_buffer *buffer); |
| 156 | void ring_buffer_record_off(struct ring_buffer *buffer); |
| 157 | void ring_buffer_record_on(struct ring_buffer *buffer); |
| 158 | int ring_buffer_record_is_on(struct ring_buffer *buffer); |
| 159 | void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu); |
| 160 | void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu); |
| 161 | |
| 162 | unsigned long ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu); |
| 163 | unsigned long ring_buffer_bytes_cpu(struct ring_buffer *buffer, int cpu); |
| 164 | unsigned long ring_buffer_entries(struct ring_buffer *buffer); |
| 165 | unsigned long ring_buffer_overruns(struct ring_buffer *buffer); |
| 166 | unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); |
| 167 | unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); |
| 168 | unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu); |
| 169 | |
| 170 | u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); |
| 171 | void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, |
| 172 | int cpu, u64 *ts); |
| 173 | void ring_buffer_set_clock(struct ring_buffer *buffer, |
| 174 | u64 (*clock)(void)); |
| 175 | |
| 176 | size_t ring_buffer_page_len(void *page); |
| 177 | |
| 178 | |
| 179 | void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu); |
| 180 | void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data); |
| 181 | int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page, |
| 182 | size_t len, int cpu, int full); |
| 183 | |
| 184 | struct trace_seq; |
| 185 | |
| 186 | int ring_buffer_print_entry_header(struct trace_seq *s); |
| 187 | int ring_buffer_print_page_header(struct trace_seq *s); |
| 188 | |
| 189 | enum ring_buffer_flags { |
| 190 | RB_FL_OVERWRITE = 1 << 0, |
| 191 | }; |
| 192 | |
| 193 | #endif /* _LINUX_RING_BUFFER_H */ |