/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_RING_BUFFER_H
#define _LINUX_RING_BUFFER_H
#include <linux/mm.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
struct ring_buffer;
struct ring_buffer_iter;
/*
* Don't refer to this struct directly, use functions below.
*/
struct ring_buffer_event {
u32 type_len:5, time_delta:27;
u32 array[];
};
/**
* enum ring_buffer_type - internal ring buffer types
*
* @RINGBUF_TYPE_PADDING: Left over page padding or discarded event
* If time_delta is 0:
* array is ignored
* size is variable depending on how much
* padding is needed
* If time_delta is non zero:
* array[0] holds the actual length
* size = 4 + length (bytes)
*
* @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
* array[0] = time delta (28 .. 59)
* size = 8 bytes
*
* @RINGBUF_TYPE_TIME_STAMP: Absolute timestamp
* Same format as TIME_EXTEND except that the
* value is an absolute timestamp, not a delta
* event.time_delta contains bottom 27 bits
* array[0] = top (28 .. 59) bits
* size = 8 bytes
*
* <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
* Data record
* If type_len is zero:
* array[0] holds the actual length
* array[1..(length+3)/4] holds data
* size = 4 + length (bytes)
* else
* length = type_len << 2
* array[0..(length+3)/4-1] holds data
* size = 4 + length (bytes)
*/
enum ring_buffer_type {
RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
RINGBUF_TYPE_PADDING,
RINGBUF_TYPE_TIME_EXTEND,
RINGBUF_TYPE_TIME_STAMP,
};
unsigned ring_buffer_event_length(struct ring_buffer_event *event);
void *ring_buffer_event_data(struct ring_buffer_event *event);
u64 ring_buffer_event_time_stamp(struct ring_buffer_event *event);
/*
* ring_buffer_discard_commit will remove an event that has not
* ben committed yet. If this is used, then ring_buffer_unlock_commit
* must not be called on the discarded event. This function
* will try to remove the event from the ring buffer completely
* if another event has not been written after it.
*
* Example use:
*
* if (some_condition)
* ring_buffer_discard_commit(buffer, event);
* else
* ring_buffer_unlock_commit(buffer, event);
*/
void ring_buffer_discard_commit(struct ring_buffer *buffer,
struct ring_buffer_event *event);
/*
* size is in bytes for each per CPU buffer.
*/
struct ring_buffer *
__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
/*
* Because the ring buffer is generic, if other users of the ring buffer get
* traced by ftrace, it can produce lockdep warnings. We need to keep each
* ring buffer's lock class separate.
*/
#define ring_buffer_alloc(size, flags) \
({ \
static struct lock_class_key __key; \
__ring_buffer_alloc((size), (flags), &__key); \
})
int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full);
__poll_t ring_buffer_poll_wait(struct ring_buffer *buffer, int cpu,
struct file *filp, poll_table *poll_table);
#define RING_BUFFER_ALL_CPUS -1
void ring_buffer_free(struct ring_buffer *buffer);
int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, int cpu);
void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val);
struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
unsigned long length);
int ring_buffer_unlock_commit(struct ring_buffer *buffer,
struct ring_buffer_event *event);
int ring_buffer_write(struct ring_buffer *buffer,
unsigned long length, void *data);
struct ring_buffer_event *
ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
unsigned long *lost_events);
struct ring_buffer_event *
ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
unsigned long *lost_events);
struct ring_buffer_iter *
ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu);
void ring_buffer_read_prepare_sync(void);
void ring_buffer_read_start(struct ring_buffer_iter *iter);
void ring_buffer_read_finish(struct ring_buffer_iter *iter);
struct ring_buffer_event *
ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
struct ring_buffer_event *
ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu);
void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
void ring_buffer_reset(struct ring_buffer *buffer);
#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
struct ring_buffer *buffer_b, int cpu);
#else
static inline int
ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
struct ring_buffer *buffer_b, int cpu)
{
return -ENODEV;
}
#endif
bool ring_buffer_empty(struct ring_buffer *buffer);
bool ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
void ring_buffer_record_disable(struct ring_buffer *buffer);
void ring_buffer_record_enable(struct ring_buffer *buffer);
void ring_buffer_record_off(struct ring_buffer *buffer);
void ring_buffer_record_on(struct ring_buffer *buffer);
int ring_buffer_record_is_on(struct ring_buffer *buffer);
void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
u64 ring_buffer_oldest_event_ts(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_bytes_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_entries(struct ring_buffer *buffer);
unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_read_events_cpu(struct ring_buffer *buffer, int cpu);
u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
int cpu, u64 *ts);
void ring_buffer_set_clock(struct ring_buffer *buffer,
u64 (*clock)(void));
void ring_buffer_set_time_stamp_abs(struct ring_buffer *buffer, bool abs);
bool ring_buffer_time_stamp_abs(struct ring_buffer *buffer);
size_t ring_buffer_page_len(void *page);
void *ring_buffer_alloc_read_page(struct ring_buffer *buffer, int cpu);
void ring_buffer_free_read_page(struct ring_buffer *buffer, int cpu, void *data);
int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
size_t len, int cpu, int full);
struct trace_seq;
int ring_buffer_print_entry_header(struct trace_seq *s);
int ring_buffer_print_page_header(struct trace_seq *s);
enum ring_buffer_flags {
RB_FL_OVERWRITE = 1 << 0,
};
#ifdef CONFIG_RING_BUFFER
int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node);
#else
#define trace_rb_cpu_prepare NULL
#endif
#endif /* _LINUX_RING_BUFFER_H */
