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 #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 kmemcheck_bitfield_begin(bitfield); 17 u32 type_len:5, time_delta:27; 18 kmemcheck_bitfield_end(bitfield); 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: Sync time stamp with external clock 40 * array[0] = tv_nsec 41 * array[1..2] = tv_sec 42 * size = 16 bytes 43 * 44 * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX: 45 * Data record 46 * If type_len is zero: 47 * array[0] holds the actual length 48 * array[1..(length+3)/4] holds data 49 * size = 4 + length (bytes) 50 * else 51 * length = type_len << 2 52 * array[0..(length+3)/4-1] holds data 53 * size = 4 + length (bytes) 54 */ 55 enum ring_buffer_type { 56 RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28, 57 RINGBUF_TYPE_PADDING, 58 RINGBUF_TYPE_TIME_EXTEND, 59 /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */ 60 RINGBUF_TYPE_TIME_STAMP, 61 }; 62 63 unsigned ring_buffer_event_length(struct ring_buffer_event *event); 64 void *ring_buffer_event_data(struct ring_buffer_event *event); 65 66 /* 67 * ring_buffer_discard_commit will remove an event that has not 68 * ben committed yet. If this is used, then ring_buffer_unlock_commit 69 * must not be called on the discarded event. This function 70 * will try to remove the event from the ring buffer completely 71 * if another event has not been written after it. 72 * 73 * Example use: 74 * 75 * if (some_condition) 76 * ring_buffer_discard_commit(buffer, event); 77 * else 78 * ring_buffer_unlock_commit(buffer, event); 79 */ 80 void ring_buffer_discard_commit(struct ring_buffer *buffer, 81 struct ring_buffer_event *event); 82 83 /* 84 * size is in bytes for each per CPU buffer. 85 */ 86 struct ring_buffer * 87 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key); 88 89 /* 90 * Because the ring buffer is generic, if other users of the ring buffer get 91 * traced by ftrace, it can produce lockdep warnings. We need to keep each 92 * ring buffer's lock class separate. 93 */ 94 #define ring_buffer_alloc(size, flags) \ 95 ({ \ 96 static struct lock_class_key __key; \ 97 __ring_buffer_alloc((size), (flags), &__key); \ 98 }) 99 100 int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full); 101 int ring_buffer_poll_wait(struct ring_buffer *buffer, int cpu, 102 struct file *filp, poll_table *poll_table); 103 104 105 #define RING_BUFFER_ALL_CPUS -1 106 107 void ring_buffer_free(struct ring_buffer *buffer); 108 109 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, int cpu); 110 111 void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val); 112 113 struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer, 114 unsigned long length); 115 int ring_buffer_unlock_commit(struct ring_buffer *buffer, 116 struct ring_buffer_event *event); 117 int ring_buffer_write(struct ring_buffer *buffer, 118 unsigned long length, void *data); 119 120 struct ring_buffer_event * 121 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts, 122 unsigned long *lost_events); 123 struct ring_buffer_event * 124 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts, 125 unsigned long *lost_events); 126 127 struct ring_buffer_iter * 128 ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu); 129 void ring_buffer_read_prepare_sync(void); 130 void ring_buffer_read_start(struct ring_buffer_iter *iter); 131 void ring_buffer_read_finish(struct ring_buffer_iter *iter); 132 133 struct ring_buffer_event * 134 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); 135 struct ring_buffer_event * 136 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts); 137 void ring_buffer_iter_reset(struct ring_buffer_iter *iter); 138 int ring_buffer_iter_empty(struct ring_buffer_iter *iter); 139 140 unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu); 141 142 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu); 143 void ring_buffer_reset(struct ring_buffer *buffer); 144 145 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP 146 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 147 struct ring_buffer *buffer_b, int cpu); 148 #else 149 static inline int 150 ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 151 struct ring_buffer *buffer_b, int cpu) 152 { 153 return -ENODEV; 154 } 155 #endif 156 157 int ring_buffer_empty(struct ring_buffer *buffer); 158 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu); 159 160 void ring_buffer_record_disable(struct ring_buffer *buffer); 161 void ring_buffer_record_enable(struct ring_buffer *buffer); 162 void ring_buffer_record_off(struct ring_buffer *buffer); 163 void ring_buffer_record_on(struct ring_buffer *buffer); 164 int ring_buffer_record_is_on(struct ring_buffer *buffer); 165 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu); 166 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu); 167 168 u64 ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu); 169 unsigned long ring_buffer_bytes_cpu(struct ring_buffer *buffer, int cpu); 170 unsigned long ring_buffer_entries(struct ring_buffer *buffer); 171 unsigned long ring_buffer_overruns(struct ring_buffer *buffer); 172 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); 173 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); 174 unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu); 175 unsigned long ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu); 176 unsigned long ring_buffer_read_events_cpu(struct ring_buffer *buffer, int cpu); 177 178 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); 179 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, 180 int cpu, u64 *ts); 181 void ring_buffer_set_clock(struct ring_buffer *buffer, 182 u64 (*clock)(void)); 183 184 size_t ring_buffer_page_len(void *page); 185 186 187 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu); 188 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data); 189 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page, 190 size_t len, int cpu, int full); 191 192 struct trace_seq; 193 194 int ring_buffer_print_entry_header(struct trace_seq *s); 195 int ring_buffer_print_page_header(struct trace_seq *s); 196 197 enum ring_buffer_flags { 198 RB_FL_OVERWRITE = 1 << 0, 199 }; 200 201 #endif /* _LINUX_RING_BUFFER_H */ 202