1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef TRACEPOINT_DEFS_H
3 #define TRACEPOINT_DEFS_H 1
4 
5 /*
6  * File can be included directly by headers who only want to access
7  * tracepoint->key to guard out of line trace calls, or the definition of
8  * trace_print_flags{_u64}. Otherwise linux/tracepoint.h should be used.
9  */
10 
11 #include <linux/atomic.h>
12 #include <linux/static_key.h>
13 
14 struct static_call_key;
15 
16 struct trace_print_flags {
17 	unsigned long		mask;
18 	const char		*name;
19 };
20 
21 struct trace_print_flags_u64 {
22 	unsigned long long	mask;
23 	const char		*name;
24 };
25 
26 struct tracepoint_func {
27 	void *func;
28 	void *data;
29 	int prio;
30 };
31 
32 struct tracepoint {
33 	const char *name;		/* Tracepoint name */
34 	struct static_key key;
35 	struct static_call_key *static_call_key;
36 	void *static_call_tramp;
37 	void *iterator;
38 	void *probestub;
39 	int (*regfunc)(void);
40 	void (*unregfunc)(void);
41 	struct tracepoint_func __rcu *funcs;
42 };
43 
44 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
45 typedef const int tracepoint_ptr_t;
46 #else
47 typedef struct tracepoint * const tracepoint_ptr_t;
48 #endif
49 
50 struct bpf_raw_event_map {
51 	struct tracepoint	*tp;
52 	void			*bpf_func;
53 	u32			num_args;
54 	u32			writable_size;
55 } __aligned(32);
56 
57 /*
58  * If a tracepoint needs to be called from a header file, it is not
59  * recommended to call it directly, as tracepoints in header files
60  * may cause side-effects and bloat the kernel. Instead, use
61  * tracepoint_enabled() to test if the tracepoint is enabled, then if
62  * it is, call a wrapper function defined in a C file that will then
63  * call the tracepoint.
64  *
65  * For "trace_foo_bar()", you would need to create a wrapper function
66  * in a C file to call trace_foo_bar():
67  *   void do_trace_foo_bar(args) { trace_foo_bar(args); }
68  * Then in the header file, declare the tracepoint:
69  *   DECLARE_TRACEPOINT(foo_bar);
70  * And call your wrapper:
71  *   static inline void some_inlined_function() {
72  *            [..]
73  *            if (tracepoint_enabled(foo_bar))
74  *                    do_trace_foo_bar(args);
75  *            [..]
76  *   }
77  *
78  * Note: tracepoint_enabled(foo_bar) is equivalent to trace_foo_bar_enabled()
79  *   but is safe to have in headers, where trace_foo_bar_enabled() is not.
80  */
81 #define DECLARE_TRACEPOINT(tp) \
82 	extern struct tracepoint __tracepoint_##tp
83 
84 #ifdef CONFIG_TRACEPOINTS
85 # define tracepoint_enabled(tp) \
86 	static_key_false(&(__tracepoint_##tp).key)
87 #else
88 # define tracepoint_enabled(tracepoint) false
89 #endif
90 
91 #endif
92