tracepoint-defs.h

 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
14struct static_call_key;
15
16struct trace_print_flags {
17	unsigned long		mask;
18	const char		*name;
19};
20
21struct trace_print_flags_u64 {
22	unsigned long long	mask;
23	const char		*name;
24};
25
26struct tracepoint_func {
27	void *func;
28	void *data;
29	int prio;
30};
31
32struct tracepoint_ext {
33	int (*regfunc)(void);
34	void (*unregfunc)(void);
35	/* Flags. */
36	unsigned int faultable:1;
37};
38
39struct tracepoint {
40	const char *name;		/* Tracepoint name */
41	struct static_key_false key;
42	struct static_call_key *static_call_key;
43	void *static_call_tramp;
44	void *iterator;
45	void *probestub;
46	struct tracepoint_func __rcu *funcs;
47	struct tracepoint_ext *ext;
48};
49
50#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
51typedef const int tracepoint_ptr_t;
52#else
53typedef struct tracepoint * const tracepoint_ptr_t;
54#endif
55
56struct bpf_raw_event_map {
57	struct tracepoint	*tp;
58	void			*bpf_func;
59	u32			num_args;
60	u32			writable_size;
61} __aligned(32);
62
63/*
64 * If a tracepoint needs to be called from a header file, it is not
65 * recommended to call it directly, as tracepoints in header files
66 * may cause side-effects and bloat the kernel. Instead, use
67 * tracepoint_enabled() to test if the tracepoint is enabled, then if
68 * it is, call a wrapper function defined in a C file that will then
69 * call the tracepoint.
70 *
71 * For "trace_foo_bar()", you would need to create a wrapper function
72 * in a C file to call trace_foo_bar():
73 *   void do_trace_foo_bar(args) { trace_foo_bar(args); }
74 * Then in the header file, declare the tracepoint:
75 *   DECLARE_TRACEPOINT(foo_bar);
76 * And call your wrapper:
77 *   static inline void some_inlined_function() {
78 *            [..]
79 *            if (tracepoint_enabled(foo_bar))
80 *                    do_trace_foo_bar(args);
81 *            [..]
82 *   }
83 *
84 * Note: tracepoint_enabled(foo_bar) is equivalent to trace_foo_bar_enabled()
85 *   but is safe to have in headers, where trace_foo_bar_enabled() is not.
86 */
87#define DECLARE_TRACEPOINT(tp) \
88	extern struct tracepoint __tracepoint_##tp
89
90#ifdef CONFIG_TRACEPOINTS
91# define tracepoint_enabled(tp) \
92	static_branch_unlikely(&(__tracepoint_##tp).key)
93#else
94# define tracepoint_enabled(tracepoint) false
95#endif
96
97#endif