linux/kernel/trace/fprobe.c

// SPDX-License-Identifier: GPL-2.0
/*
 * fprobe - Simple ftrace probe wrapper for function entry.
 */
#define pr_fmt(fmt) …

#include <linux/err.h>
#include <linux/fprobe.h>
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/rethook.h>
#include <linux/slab.h>
#include <linux/sort.h>

#include "trace.h"

struct fprobe_rethook_node { … };

static inline void __fprobe_handler(unsigned long ip, unsigned long parent_ip,
			struct ftrace_ops *ops, struct ftrace_regs *fregs)
{ … }

static void fprobe_handler(unsigned long ip, unsigned long parent_ip,
		struct ftrace_ops *ops, struct ftrace_regs *fregs)
{ … }
NOKPROBE_SYMBOL(fprobe_handler);

static void fprobe_kprobe_handler(unsigned long ip, unsigned long parent_ip,
				  struct ftrace_ops *ops, struct ftrace_regs *fregs)
{ … }

static void fprobe_exit_handler(struct rethook_node *rh, void *data,
				unsigned long ret_ip, struct pt_regs *regs)
{ … }
NOKPROBE_SYMBOL(fprobe_exit_handler);

static int symbols_cmp(const void *a, const void *b)
{ … }

/* Convert ftrace location address from symbols */
static unsigned long *get_ftrace_locations(const char **syms, int num)
{ … }

static void fprobe_init(struct fprobe *fp)
{ … }

static int fprobe_init_rethook(struct fprobe *fp, int num)
{ … }

static void fprobe_fail_cleanup(struct fprobe *fp)
{ … }

/**
 * register_fprobe() - Register fprobe to ftrace by pattern.
 * @fp: A fprobe data structure to be registered.
 * @filter: A wildcard pattern of probed symbols.
 * @notfilter: A wildcard pattern of NOT probed symbols.
 *
 * Register @fp to ftrace for enabling the probe on the symbols matched to @filter.
 * If @notfilter is not NULL, the symbols matched the @notfilter are not probed.
 *
 * Return 0 if @fp is registered successfully, -errno if not.
 */
int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * register_fprobe_ips() - Register fprobe to ftrace by address.
 * @fp: A fprobe data structure to be registered.
 * @addrs: An array of target ftrace location addresses.
 * @num: The number of entries of @addrs.
 *
 * Register @fp to ftrace for enabling the probe on the address given by @addrs.
 * The @addrs must be the addresses of ftrace location address, which may be
 * the symbol address + arch-dependent offset.
 * If you unsure what this mean, please use other registration functions.
 *
 * Return 0 if @fp is registered successfully, -errno if not.
 */
int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * register_fprobe_syms() - Register fprobe to ftrace by symbols.
 * @fp: A fprobe data structure to be registered.
 * @syms: An array of target symbols.
 * @num: The number of entries of @syms.
 *
 * Register @fp to the symbols given by @syms array. This will be useful if
 * you are sure the symbols exist in the kernel.
 *
 * Return 0 if @fp is registered successfully, -errno if not.
 */
int register_fprobe_syms(struct fprobe *fp, const char **syms, int num)
{ … }
EXPORT_SYMBOL_GPL(…);

bool fprobe_is_registered(struct fprobe *fp)
{ … }

/**
 * unregister_fprobe() - Unregister fprobe from ftrace
 * @fp: A fprobe data structure to be unregistered.
 *
 * Unregister fprobe (and remove ftrace hooks from the function entries).
 *
 * Return 0 if @fp is unregistered successfully, -errno if not.
 */
int unregister_fprobe(struct fprobe *fp)
{ … }
EXPORT_SYMBOL_GPL(…);