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