/*
* auxtrace.h: AUX area trace support
* Copyright (c) 2013-2015, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
*/
#ifndef __PERF_AUXTRACE_H
#define __PERF_AUXTRACE_H
#include <sys/types.h>
#include <stdbool.h>
#include <linux/perf_event.h>
#include <linux/types.h>
#include "../perf.h"
struct perf_evlist;
/**
* struct auxtrace_mmap - records an mmap of the auxtrace buffer.
* @base: address of mapped area
* @userpg: pointer to buffer's perf_event_mmap_page
* @mask: %0 if @len is not a power of two, otherwise (@len - %1)
* @len: size of mapped area
* @prev: previous aux_head
* @idx: index of this mmap
* @tid: tid for a per-thread mmap (also set if there is only 1 tid on a per-cpu
* mmap) otherwise %0
* @cpu: cpu number for a per-cpu mmap otherwise %-1
*/
struct auxtrace_mmap {
void *base;
void *userpg;
size_t mask;
size_t len;
u64 prev;
int idx;
pid_t tid;
int cpu;
};
/**
* struct auxtrace_mmap_params - parameters to set up struct auxtrace_mmap.
* @mask: %0 if @len is not a power of two, otherwise (@len - %1)
* @offset: file offset of mapped area
* @len: size of mapped area
* @prot: mmap memory protection
* @idx: index of this mmap
* @tid: tid for a per-thread mmap (also set if there is only 1 tid on a per-cpu
* mmap) otherwise %0
* @cpu: cpu number for a per-cpu mmap otherwise %-1
*/
struct auxtrace_mmap_params {
size_t mask;
off_t offset;
size_t len;
int prot;
int idx;
pid_t tid;
int cpu;
};
static inline u64 auxtrace_mmap__read_head(struct auxtrace_mmap *mm)
{
struct perf_event_mmap_page *pc = mm->userpg;
#if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
u64 head = ACCESS_ONCE(pc->aux_head);
#else
u64 head = __sync_val_compare_and_swap(&pc->aux_head, 0, 0);
#endif
/* Ensure all reads are done after we read the head */
rmb();
return head;
}
static inline void auxtrace_mmap__write_tail(struct auxtrace_mmap *mm, u64 tail)
{
struct perf_event_mmap_page *pc = mm->userpg;
#if BITS_PER_LONG != 64 && defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
u64 old_tail;
#endif
/* Ensure all reads are done before we write the tail out */
mb();
#if BITS_PER_LONG == 64 || !defined(HAVE_SYNC_COMPARE_AND_SWAP_SUPPORT)
pc->aux_tail = tail;
#else
do {
old_tail = __sync_val_compare_and_swap(&pc->aux_tail, 0, 0);
} while (!__sync_bool_compare_and_swap(&pc->aux_tail, old_tail, tail));
#endif
}
int auxtrace_mmap__mmap(struct auxtrace_mmap *mm,
struct auxtrace_mmap_params *mp,
void *userpg, int fd);
void auxtrace_mmap__munmap(struct auxtrace_mmap *mm);
void auxtrace_mmap_params__init(struct auxtrace_mmap_params *mp,
off_t auxtrace_offset,
unsigned int auxtrace_pages,
bool auxtrace_overwrite);
void auxtrace_mmap_params__set_idx(struct auxtrace_mmap_params *mp,
struct perf_evlist *evlist, int idx,
bool per_cpu);
#endif
