trace_helpers.h

/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
#ifndef __TRACE_HELPERS_H
#define __TRACE_HELPERS_H

#include <stdbool.h>

#define NSEC_PER_SEC 1000000000ULL

void print_log2_hist(unsigned int* vals, int vals_size, const char* val_type);
void print_linear_hist(unsigned int* vals,
                       int vals_size,
                       unsigned int base,
                       unsigned int step,
                       const char* val_type);

unsigned long long get_ktime_ns(void);

bool is_kernel_module(const char* name);

/*
 * When attempting to use kprobe/kretprobe, please check out new fentry/fexit
 * probes, as they provide better performance and usability. But in some
 * situations we have to fallback to kprobe/kretprobe probes. This helper
 * is used to detect fentry/fexit support for the specified kernel function.
 *
 *	1. A gap between kernel versions, kernel BTF is exposed
 * 	   starting from 5.4 kernel. but fentry/fexit is actually
 * 	   supported starting from 5.5.
 *	2. Whether kernel supports module BTF or not
 *
 * *name* is the name of a kernel function to be attached to, which can be
 * from vmlinux or a kernel module.
 * *mod* is a hint that indicates the *name* may reside in module BTF,
 * if NULL, it means *name* belongs to vmlinux.
 */
bool fentry_can_attach(const char* name, const char* mod);

/*
 * The name of a kernel function to be attached to may be changed between
 * kernel releases. This helper is used to confirm whether the target kernel
 * uses a certain function name before attaching.
 *
 * It is achieved by scaning
 * 	/sys/kernel/debug/tracing/available_filter_functions
 * If this file does not exist, it fallbacks to parse /proc/kallsyms,
 * which is slower.
 */
bool kprobe_exists(const char* name);
bool tracepoint_exists(const char* category, const char* event);

bool vmlinux_btf_exists(void);
bool module_btf_exists(const char* mod);

bool probe_tp_btf(const char* name);
bool probe_ringbuf();

#endif /* __TRACE_HELPERS_H */