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/rethook.h>
9
10 /**
11 * struct fprobe - ftrace based probe.
12 * @ops: The ftrace_ops.
13 * @nmissed: The counter for missing events.
14 * @flags: The status flag.
15 * @rethook: The rethook data structure. (internal data)
16 * @entry_data_size: The private data storage size.
17 * @nr_maxactive: The max number of active functions.
18 * @entry_handler: The callback function for function entry.
19 * @exit_handler: The callback function for function exit.
20 */
21 struct fprobe {
22 #ifdef CONFIG_FUNCTION_TRACER
23 /*
24 * If CONFIG_FUNCTION_TRACER is not set, CONFIG_FPROBE is disabled too.
25 * But user of fprobe may keep embedding the struct fprobe on their own
26 * code. To avoid build error, this will keep the fprobe data structure
27 * defined here, but remove ftrace_ops data structure.
28 */
29 struct ftrace_ops ops;
30 #endif
31 unsigned long nmissed;
32 unsigned int flags;
33 struct rethook *rethook;
34 size_t entry_data_size;
35 int nr_maxactive;
36
37 int (*entry_handler)(struct fprobe *fp, unsigned long entry_ip,
38 unsigned long ret_ip, struct pt_regs *regs,
39 void *entry_data);
40 void (*exit_handler)(struct fprobe *fp, unsigned long entry_ip,
41 unsigned long ret_ip, struct pt_regs *regs,
42 void *entry_data);
43 };
44
45 /* This fprobe is soft-disabled. */
46 #define FPROBE_FL_DISABLED 1
47
48 /*
49 * This fprobe handler will be shared with kprobes.
50 * This flag must be set before registering.
51 */
52 #define FPROBE_FL_KPROBE_SHARED 2
53
fprobe_disabled(struct fprobe * fp)54 static inline bool fprobe_disabled(struct fprobe *fp)
55 {
56 return (fp) ? fp->flags & FPROBE_FL_DISABLED : false;
57 }
58
fprobe_shared_with_kprobes(struct fprobe * fp)59 static inline bool fprobe_shared_with_kprobes(struct fprobe *fp)
60 {
61 return (fp) ? fp->flags & FPROBE_FL_KPROBE_SHARED : false;
62 }
63
64 #ifdef CONFIG_FPROBE
65 int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter);
66 int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num);
67 int register_fprobe_syms(struct fprobe *fp, const char **syms, int num);
68 int unregister_fprobe(struct fprobe *fp);
69 bool fprobe_is_registered(struct fprobe *fp);
70 #else
register_fprobe(struct fprobe * fp,const char * filter,const char * notfilter)71 static inline int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter)
72 {
73 return -EOPNOTSUPP;
74 }
register_fprobe_ips(struct fprobe * fp,unsigned long * addrs,int num)75 static inline int register_fprobe_ips(struct fprobe *fp, unsigned long *addrs, int num)
76 {
77 return -EOPNOTSUPP;
78 }
register_fprobe_syms(struct fprobe * fp,const char ** syms,int num)79 static inline int register_fprobe_syms(struct fprobe *fp, const char **syms, int num)
80 {
81 return -EOPNOTSUPP;
82 }
unregister_fprobe(struct fprobe * fp)83 static inline int unregister_fprobe(struct fprobe *fp)
84 {
85 return -EOPNOTSUPP;
86 }
fprobe_is_registered(struct fprobe * fp)87 static inline bool fprobe_is_registered(struct fprobe *fp)
88 {
89 return false;
90 }
91 #endif
92
93 /**
94 * disable_fprobe() - Disable fprobe
95 * @fp: The fprobe to be disabled.
96 *
97 * This will soft-disable @fp. Note that this doesn't remove the ftrace
98 * hooks from the function entry.
99 */
disable_fprobe(struct fprobe * fp)100 static inline void disable_fprobe(struct fprobe *fp)
101 {
102 if (fp)
103 fp->flags |= FPROBE_FL_DISABLED;
104 }
105
106 /**
107 * enable_fprobe() - Enable fprobe
108 * @fp: The fprobe to be enabled.
109 *
110 * This will soft-enable @fp.
111 */
enable_fprobe(struct fprobe * fp)112 static inline void enable_fprobe(struct fprobe *fp)
113 {
114 if (fp)
115 fp->flags &= ~FPROBE_FL_DISABLED;
116 }
117
118 #endif
119