trace_helpers.h

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/* 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
 
struct ksym {
    const char *name;
    unsigned long addr;
};
 
struct ksyms;
 
struct ksyms *ksyms__load(void);
void ksyms__free(struct ksyms *ksyms);
const struct ksym *ksyms__map_addr(const struct ksyms *ksyms,
                   unsigned long addr);
const struct ksym *ksyms__get_symbol(const struct ksyms *ksyms,
                     const char *name);
 
struct sym {
    const char *name;
    unsigned long start;
    unsigned long size;
};
 
struct syms;
 
struct syms *syms__load_pid(int tgid);
struct syms *syms__load_file(const char *fname);
void syms__free(struct syms *syms);
const struct sym *syms__map_addr(const struct syms *syms, unsigned long addr);
 
struct syms_cache;
 
struct syms_cache *syms_cache__new(int nr);
struct syms *syms_cache__get_syms(struct syms_cache *syms_cache, int tgid);
void syms_cache__free(struct syms_cache *syms_cache);
 
struct partition {
    char *name;
    unsigned int dev;
};
 
struct partitions;
 
struct partitions *partitions__load(void);
void partitions__free(struct partitions *partitions);
const struct partition *
partitions__get_by_dev(const struct partitions *partitions, unsigned int dev);
const struct partition *
partitions__get_by_name(const struct partitions *partitions, const char *name);
 
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 vmlinux_btf_exists(void);
bool module_btf_exists(const char *mod);
 
#endif /* __TRACE_HELPERS_H */