/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _TRACE_MMAP_H_
#define _TRACE_MMAP_H_

#include <linux/types.h>

/**
 * struct trace_buffer_meta - Ring-buffer Meta-page description
 * @meta_page_size:     Size of this meta-page.
 * @meta_struct_len:    Size of this structure.
 * @subbuf_size:        Size of each sub-buffer.
 * @nr_subbufs:         Number of subbfs in the ring-buffer, including the reader.
 * @reader.lost_events: Number of events lost at the time of the reader swap.
 * @reader.id:          subbuf ID of the current reader. ID range [0 : @nr_subbufs - 1]
 * @reader.read:        Number of bytes read on the reader subbuf.
 * @flags:              Placeholder for now, 0 until new features are supported.
 * @entries:            Number of entries in the ring-buffer.
 * @overrun:            Number of entries lost in the ring-buffer.
 * @read:               Number of entries that have been read.
 * @Reserved1:          Internal use only.
 * @Reserved2:          Internal use only.
 */
struct trace_buffer_meta {
        __u32           meta_page_size;
        __u32           meta_struct_len;

        __u32           subbuf_size;
        __u32           nr_subbufs;

        struct {
                __u64   lost_events;
                __u32   id;
                __u32   read;
        } reader;

        __u64   flags;

        __u64   entries;
        __u64   overrun;
        __u64   read;

        __u64   Reserved1;
        __u64   Reserved2;
};

#define TRACE_MMAP_IOCTL_GET_READER             _IO('R', 0x20)

#endif /* _TRACE_MMAP_H_ */