1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_RING_BUFFER_H 3 #define _LINUX_RING_BUFFER_H 4 5 #include <linux/mm.h> 6 #include <linux/seq_file.h> 7 #include <linux/poll.h> 8 9 #include <uapi/linux/trace_mmap.h> 10 11 struct trace_buffer; 12 struct ring_buffer_iter; 13 14 /* 15 * Don't refer to this struct directly, use functions below. 16 */ 17 struct ring_buffer_event { 18 u32 type_len:5, time_delta:27; 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: Absolute timestamp 40 * Same format as TIME_EXTEND except that the 41 * value is an absolute timestamp, not a delta 42 * event.time_delta contains bottom 27 bits 43 * array[0] = top (28 .. 59) bits 44 * size = 8 bytes 45 * 46 * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX: 47 * Data record 48 * If type_len is zero: 49 * array[0] holds the actual length 50 * array[1..(length+3)/4] holds data 51 * size = 4 + length (bytes) 52 * else 53 * length = type_len << 2 54 * array[0..(length+3)/4-1] holds data 55 * size = 4 + length (bytes) 56 */ 57 enum ring_buffer_type { 58 RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28, 59 RINGBUF_TYPE_PADDING, 60 RINGBUF_TYPE_TIME_EXTEND, 61 RINGBUF_TYPE_TIME_STAMP, 62 }; 63 64 unsigned ring_buffer_event_length(struct ring_buffer_event *event); 65 void *ring_buffer_event_data(struct ring_buffer_event *event); 66 u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer, 67 struct ring_buffer_event *event); 68 69 /* 70 * ring_buffer_discard_commit will remove an event that has not 71 * been committed yet. If this is used, then ring_buffer_unlock_commit 72 * must not be called on the discarded event. This function 73 * will try to remove the event from the ring buffer completely 74 * if another event has not been written after it. 75 * 76 * Example use: 77 * 78 * if (some_condition) 79 * ring_buffer_discard_commit(buffer, event); 80 * else 81 * ring_buffer_unlock_commit(buffer, event); 82 */ 83 void ring_buffer_discard_commit(struct trace_buffer *buffer, 84 struct ring_buffer_event *event); 85 86 /* 87 * size is in bytes for each per CPU buffer. 88 */ 89 struct trace_buffer * 90 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key); 91 92 struct trace_buffer *__ring_buffer_alloc_range(unsigned long size, unsigned flags, 93 int order, unsigned long start, 94 unsigned long range_size, 95 struct lock_class_key *key); 96 97 bool ring_buffer_last_boot_delta(struct trace_buffer *buffer, long *text, 98 long *data); 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 /* 112 * Because the ring buffer is generic, if other users of the ring buffer get 113 * traced by ftrace, it can produce lockdep warnings. We need to keep each 114 * ring buffer's lock class separate. 115 */ 116 #define ring_buffer_alloc_range(size, flags, order, start, range_size) \ 117 ({ \ 118 static struct lock_class_key __key; \ 119 __ring_buffer_alloc_range((size), (flags), (order), (start), \ 120 (range_size), &__key); \ 121 }) 122 123 typedef bool (*ring_buffer_cond_fn)(void *data); 124 int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full, 125 ring_buffer_cond_fn cond, void *data); 126 __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, 127 struct file *filp, poll_table *poll_table, int full); 128 void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu); 129 130 #define RING_BUFFER_ALL_CPUS -1 131 132 void ring_buffer_free(struct trace_buffer *buffer); 133 134 int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu); 135 136 void ring_buffer_change_overwrite(struct trace_buffer *buffer, int val); 137 138 struct ring_buffer_event *ring_buffer_lock_reserve(struct trace_buffer *buffer, 139 unsigned long length); 140 int ring_buffer_unlock_commit(struct trace_buffer *buffer); 141 int ring_buffer_write(struct trace_buffer *buffer, 142 unsigned long length, void *data); 143 144 void ring_buffer_nest_start(struct trace_buffer *buffer); 145 void ring_buffer_nest_end(struct trace_buffer *buffer); 146 147 struct ring_buffer_event * 148 ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts, 149 unsigned long *lost_events); 150 struct ring_buffer_event * 151 ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts, 152 unsigned long *lost_events); 153 154 struct ring_buffer_iter * 155 ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags); 156 void ring_buffer_read_prepare_sync(void); 157 void ring_buffer_read_start(struct ring_buffer_iter *iter); 158 void ring_buffer_read_finish(struct ring_buffer_iter *iter); 159 160 struct ring_buffer_event * 161 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); 162 void ring_buffer_iter_advance(struct ring_buffer_iter *iter); 163 void ring_buffer_iter_reset(struct ring_buffer_iter *iter); 164 int ring_buffer_iter_empty(struct ring_buffer_iter *iter); 165 bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter); 166 167 unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu); 168 unsigned long ring_buffer_max_event_size(struct trace_buffer *buffer); 169 170 void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu); 171 void ring_buffer_reset_online_cpus(struct trace_buffer *buffer); 172 void ring_buffer_reset(struct trace_buffer *buffer); 173 174 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP 175 int ring_buffer_swap_cpu(struct trace_buffer *buffer_a, 176 struct trace_buffer *buffer_b, int cpu); 177 #else 178 static inline int ring_buffer_swap_cpu(struct trace_buffer * buffer_a,struct trace_buffer * buffer_b,int cpu)179 ring_buffer_swap_cpu(struct trace_buffer *buffer_a, 180 struct trace_buffer *buffer_b, int cpu) 181 { 182 return -ENODEV; 183 } 184 #endif 185 186 bool ring_buffer_empty(struct trace_buffer *buffer); 187 bool ring_buffer_empty_cpu(struct trace_buffer *buffer, int cpu); 188 189 void ring_buffer_record_disable(struct trace_buffer *buffer); 190 void ring_buffer_record_enable(struct trace_buffer *buffer); 191 void ring_buffer_record_off(struct trace_buffer *buffer); 192 void ring_buffer_record_on(struct trace_buffer *buffer); 193 bool ring_buffer_record_is_on(struct trace_buffer *buffer); 194 bool ring_buffer_record_is_set_on(struct trace_buffer *buffer); 195 void ring_buffer_record_disable_cpu(struct trace_buffer *buffer, int cpu); 196 void ring_buffer_record_enable_cpu(struct trace_buffer *buffer, int cpu); 197 198 u64 ring_buffer_oldest_event_ts(struct trace_buffer *buffer, int cpu); 199 unsigned long ring_buffer_bytes_cpu(struct trace_buffer *buffer, int cpu); 200 unsigned long ring_buffer_entries(struct trace_buffer *buffer); 201 unsigned long ring_buffer_overruns(struct trace_buffer *buffer); 202 unsigned long ring_buffer_entries_cpu(struct trace_buffer *buffer, int cpu); 203 unsigned long ring_buffer_overrun_cpu(struct trace_buffer *buffer, int cpu); 204 unsigned long ring_buffer_commit_overrun_cpu(struct trace_buffer *buffer, int cpu); 205 unsigned long ring_buffer_dropped_events_cpu(struct trace_buffer *buffer, int cpu); 206 unsigned long ring_buffer_read_events_cpu(struct trace_buffer *buffer, int cpu); 207 208 u64 ring_buffer_time_stamp(struct trace_buffer *buffer); 209 void ring_buffer_normalize_time_stamp(struct trace_buffer *buffer, 210 int cpu, u64 *ts); 211 void ring_buffer_set_clock(struct trace_buffer *buffer, 212 u64 (*clock)(void)); 213 void ring_buffer_set_time_stamp_abs(struct trace_buffer *buffer, bool abs); 214 bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer); 215 216 size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu); 217 218 struct buffer_data_read_page; 219 struct buffer_data_read_page * 220 ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu); 221 void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, 222 struct buffer_data_read_page *page); 223 int ring_buffer_read_page(struct trace_buffer *buffer, 224 struct buffer_data_read_page *data_page, 225 size_t len, int cpu, int full); 226 void *ring_buffer_read_page_data(struct buffer_data_read_page *page); 227 228 struct trace_seq; 229 230 int ring_buffer_print_entry_header(struct trace_seq *s); 231 int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s); 232 233 int ring_buffer_subbuf_order_get(struct trace_buffer *buffer); 234 int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order); 235 int ring_buffer_subbuf_size_get(struct trace_buffer *buffer); 236 237 enum ring_buffer_flags { 238 RB_FL_OVERWRITE = 1 << 0, 239 }; 240 241 #ifdef CONFIG_RING_BUFFER 242 int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node); 243 #else 244 #define trace_rb_cpu_prepare NULL 245 #endif 246 247 int ring_buffer_map(struct trace_buffer *buffer, int cpu, 248 struct vm_area_struct *vma); 249 int ring_buffer_unmap(struct trace_buffer *buffer, int cpu); 250 int ring_buffer_map_get_reader(struct trace_buffer *buffer, int cpu); 251 #endif /* _LINUX_RING_BUFFER_H */ 252