Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0 */
2/* Simple ftrace probe wrapper */
3#ifndef _LINUX_FPROBE_H
4#define _LINUX_FPROBE_H
5
6#include <linux/compiler.h>
7#include <linux/ftrace.h>
8#include <linux/rcupdate.h>
9#include <linux/refcount.h>
10#include <linux/slab.h>
11
12struct fprobe;
13typedef int (*fprobe_entry_cb)(struct fprobe *fp, unsigned long entry_ip,
14 unsigned long ret_ip, struct ftrace_regs *regs,
15 void *entry_data);
16
17typedef void (*fprobe_exit_cb)(struct fprobe *fp, unsigned long entry_ip,
18 unsigned long ret_ip, struct ftrace_regs *regs,
19 void *entry_data);
20
21/**
22 * struct fprobe_hlist_node - address based hash list node for fprobe.
23 *
24 * @hlist: The hlist node for address search hash table.
25 * @addr: One of the probing address of @fp.
26 * @fp: The fprobe which owns this.
27 */
28struct fprobe_hlist_node {
29 struct hlist_node hlist;
30 unsigned long addr;
31 struct fprobe *fp;
32};
33
34/**
35 * struct fprobe_hlist - hash list nodes for fprobe.
36 *
37 * @hlist: The hlist node for existence checking hash table.
38 * @rcu: rcu_head for RCU deferred release.
39 * @fp: The fprobe which owns this fprobe_hlist.
40 * @size: The size of @array.
41 * @array: The fprobe_hlist_node for each address to probe.
42 */
43struct fprobe_hlist {
44 struct hlist_node hlist;
45 struct rcu_head rcu;
46 struct fprobe *fp;
47 int size;
48 struct fprobe_hlist_node array[] __counted_by(size);
49};
50
51/**
52 * struct fprobe - ftrace based probe.
53 *
54 * @nmissed: The counter for missing events.
55 * @flags: The status flag.
56 * @entry_data_size: The private data storage size.
57 * @entry_handler: The callback function for function entry.
58 * @exit_handler: The callback function for function exit.
59 * @hlist_array: The fprobe_hlist for fprobe search from IP hash table.
60 */
61struct fprobe {
62 unsigned long nmissed;
63 unsigned int flags;
64 size_t entry_data_size;
65
66 fprobe_entry_cb entry_handler;
67 fprobe_exit_cb exit_handler;
68
69 struct fprobe_hlist *hlist_array;
70};
71
72/* This fprobe is soft-disabled. */
73#define FPROBE_FL_DISABLED 1
74
75/*
76 * This fprobe handler will be shared with kprobes.
77 * This flag must be set before registering.
78 */
79#define FPROBE_FL_KPROBE_SHARED 2
80
81static inline bool fprobe_disabled(struct fprobe *fp)
82{
83 return (fp) ? fp->flags & FPROBE_FL_DISABLED : false;
84}
85
86static inline bool fprobe_shared_with_kprobes(struct fprobe *fp)
87{
88 return (fp) ? fp->flags & FPROBE_FL_KPROBE_SHARED : false;
89}
90
91#ifdef CONFIG_FPROBE
92int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter);
93int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num);
94int register_fprobe_syms(struct fprobe *fp, const char **syms, int num);
95int unregister_fprobe(struct fprobe *fp);
96bool fprobe_is_registered(struct fprobe *fp);
97int fprobe_count_ips_from_filter(const char *filter, const char *notfilter);
98#else
99static inline int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter)
100{
101 return -EOPNOTSUPP;
102}
103static inline int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num)
104{
105 return -EOPNOTSUPP;
106}
107static inline int register_fprobe_syms(struct fprobe *fp, const char **syms, int num)
108{
109 return -EOPNOTSUPP;
110}
111static inline int unregister_fprobe(struct fprobe *fp)
112{
113 return -EOPNOTSUPP;
114}
115static inline bool fprobe_is_registered(struct fprobe *fp)
116{
117 return false;
118}
119static inline int fprobe_count_ips_from_filter(const char *filter, const char *notfilter)
120{
121 return -EOPNOTSUPP;
122}
123#endif
124
125/**
126 * disable_fprobe() - Disable fprobe
127 * @fp: The fprobe to be disabled.
128 *
129 * This will soft-disable @fp. Note that this doesn't remove the ftrace
130 * hooks from the function entry.
131 */
132static inline void disable_fprobe(struct fprobe *fp)
133{
134 if (fp)
135 fp->flags |= FPROBE_FL_DISABLED;
136}
137
138/**
139 * enable_fprobe() - Enable fprobe
140 * @fp: The fprobe to be enabled.
141 *
142 * This will soft-enable @fp.
143 */
144static inline void enable_fprobe(struct fprobe *fp)
145{
146 if (fp)
147 fp->flags &= ~FPROBE_FL_DISABLED;
148}
149
150/* The entry data size is 4 bits (=16) * sizeof(long) in maximum */
151#define FPROBE_DATA_SIZE_BITS 4
152#define MAX_FPROBE_DATA_SIZE_WORD ((1L << FPROBE_DATA_SIZE_BITS) - 1)
153#define MAX_FPROBE_DATA_SIZE (MAX_FPROBE_DATA_SIZE_WORD * sizeof(long))
154
155#endif