1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 2#ifndef _TRACE_MMAP_H_
 3#define _TRACE_MMAP_H_
 4
 5#include <linux/types.h>
 6
 7/**
 8 * struct trace_buffer_meta - Ring-buffer Meta-page description
 9 * @meta_page_size:	Size of this meta-page.
10 * @meta_struct_len:	Size of this structure.
11 * @subbuf_size:	Size of each sub-buffer.
12 * @nr_subbufs:		Number of subbfs in the ring-buffer, including the reader.
13 * @reader.lost_events:	Number of events lost at the time of the reader swap.
14 * @reader.id:		subbuf ID of the current reader. ID range [0 : @nr_subbufs - 1]
15 * @reader.read:	Number of bytes read on the reader subbuf.
16 * @flags:		Placeholder for now, 0 until new features are supported.
17 * @entries:		Number of entries in the ring-buffer.
18 * @overrun:		Number of entries lost in the ring-buffer.
19 * @read:		Number of entries that have been read.
20 * @Reserved1:		Internal use only.
21 * @Reserved2:		Internal use only.
22 */
23struct trace_buffer_meta {
24	__u32		meta_page_size;
25	__u32		meta_struct_len;
26
27	__u32		subbuf_size;
28	__u32		nr_subbufs;
29
30	struct {
31		__u64	lost_events;
32		__u32	id;
33		__u32	read;
34	} reader;
35
36	__u64	flags;
37
38	__u64	entries;
39	__u64	overrun;
40	__u64	read;
41
42	__u64	Reserved1;
43	__u64	Reserved2;
44};
45
46#define TRACE_MMAP_IOCTL_GET_READER		_IO('R', 0x20)
47
48#endif /* _TRACE_MMAP_H_ */