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_event_time_delta - return the delta timestamp of the event 67 * @event: the event to get the delta timestamp of 68 * 69 * The delta timestamp is the 27 bit timestamp since the last event. 70 */ 71 static inline unsigned 72 ring_buffer_event_time_delta(struct ring_buffer_event *event) 73 { 74 return event->time_delta; 75 } 76 77 /* 78 * ring_buffer_discard_commit will remove an event that has not 79 * ben committed yet. If this is used, then ring_buffer_unlock_commit 80 * must not be called on the discarded event. This function 81 * will try to remove the event from the ring buffer completely 82 * if another event has not been written after it. 83 * 84 * Example use: 85 * 86 * if (some_condition) 87 * ring_buffer_discard_commit(buffer, event); 88 * else 89 * ring_buffer_unlock_commit(buffer, event); 90 */ 91 void ring_buffer_discard_commit(struct ring_buffer *buffer, 92 struct ring_buffer_event *event); 93 94 /* 95 * size is in bytes for each per CPU buffer. 96 */ 97 struct ring_buffer * 98 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key); 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 void ring_buffer_free(struct ring_buffer *buffer); 112 113 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size); 114 115 struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer, 116 unsigned long length); 117 int ring_buffer_unlock_commit(struct ring_buffer *buffer, 118 struct ring_buffer_event *event); 119 int ring_buffer_write(struct ring_buffer *buffer, 120 unsigned long length, void *data); 121 122 struct ring_buffer_event * 123 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts, 124 unsigned long *lost_events); 125 struct ring_buffer_event * 126 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts, 127 unsigned long *lost_events); 128 129 struct ring_buffer_iter * 130 ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu); 131 void ring_buffer_read_prepare_sync(void); 132 void ring_buffer_read_start(struct ring_buffer_iter *iter); 133 void ring_buffer_read_finish(struct ring_buffer_iter *iter); 134 135 struct ring_buffer_event * 136 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); 137 struct ring_buffer_event * 138 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts); 139 void ring_buffer_iter_reset(struct ring_buffer_iter *iter); 140 int ring_buffer_iter_empty(struct ring_buffer_iter *iter); 141 142 unsigned long ring_buffer_size(struct ring_buffer *buffer); 143 144 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu); 145 void ring_buffer_reset(struct ring_buffer *buffer); 146 147 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP 148 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 149 struct ring_buffer *buffer_b, int cpu); 150 #else 151 static inline int 152 ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 153 struct ring_buffer *buffer_b, int cpu) 154 { 155 return -ENODEV; 156 } 157 #endif 158 159 int ring_buffer_empty(struct ring_buffer *buffer); 160 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu); 161 162 void ring_buffer_record_disable(struct ring_buffer *buffer); 163 void ring_buffer_record_enable(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 unsigned long ring_buffer_entries(struct ring_buffer *buffer); 168 unsigned long ring_buffer_overruns(struct ring_buffer *buffer); 169 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); 170 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); 171 unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu); 172 173 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); 174 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, 175 int cpu, u64 *ts); 176 void ring_buffer_set_clock(struct ring_buffer *buffer, 177 u64 (*clock)(void)); 178 179 size_t ring_buffer_page_len(void *page); 180 181 182 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer); 183 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data); 184 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page, 185 size_t len, int cpu, int full); 186 187 struct trace_seq; 188 189 int ring_buffer_print_entry_header(struct trace_seq *s); 190 int ring_buffer_print_page_header(struct trace_seq *s); 191 192 enum ring_buffer_flags { 193 RB_FL_OVERWRITE = 1 << 0, 194 }; 195 196 #endif /* _LINUX_RING_BUFFER_H */ 197