xref: /openbmc/linux/include/trace/bpf_probe.h (revision 3a83e4e6)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 #undef TRACE_SYSTEM_VAR
4 
5 #ifdef CONFIG_BPF_EVENTS
6 
7 #undef __entry
8 #define __entry entry
9 
10 #undef __get_dynamic_array
11 #define __get_dynamic_array(field)	\
12 		((void *)__entry + (__entry->__data_loc_##field & 0xffff))
13 
14 #undef __get_dynamic_array_len
15 #define __get_dynamic_array_len(field)	\
16 		((__entry->__data_loc_##field >> 16) & 0xffff)
17 
18 #undef __get_str
19 #define __get_str(field) ((char *)__get_dynamic_array(field))
20 
21 #undef __get_bitmask
22 #define __get_bitmask(field) (char *)__get_dynamic_array(field)
23 
24 #undef __perf_count
25 #define __perf_count(c)	(c)
26 
27 #undef __perf_task
28 #define __perf_task(t)	(t)
29 
30 /* cast any integer, pointer, or small struct to u64 */
31 #define UINTTYPE(size) \
32 	__typeof__(__builtin_choose_expr(size == 1,  (u8)1, \
33 		   __builtin_choose_expr(size == 2, (u16)2, \
34 		   __builtin_choose_expr(size == 4, (u32)3, \
35 		   __builtin_choose_expr(size == 8, (u64)4, \
36 					 (void)5)))))
37 #define __CAST_TO_U64(x) ({ \
38 	typeof(x) __src = (x); \
39 	UINTTYPE(sizeof(x)) __dst; \
40 	memcpy(&__dst, &__src, sizeof(__dst)); \
41 	(u64)__dst; })
42 
43 #define __CAST1(a,...) __CAST_TO_U64(a)
44 #define __CAST2(a,...) __CAST_TO_U64(a), __CAST1(__VA_ARGS__)
45 #define __CAST3(a,...) __CAST_TO_U64(a), __CAST2(__VA_ARGS__)
46 #define __CAST4(a,...) __CAST_TO_U64(a), __CAST3(__VA_ARGS__)
47 #define __CAST5(a,...) __CAST_TO_U64(a), __CAST4(__VA_ARGS__)
48 #define __CAST6(a,...) __CAST_TO_U64(a), __CAST5(__VA_ARGS__)
49 #define __CAST7(a,...) __CAST_TO_U64(a), __CAST6(__VA_ARGS__)
50 #define __CAST8(a,...) __CAST_TO_U64(a), __CAST7(__VA_ARGS__)
51 #define __CAST9(a,...) __CAST_TO_U64(a), __CAST8(__VA_ARGS__)
52 #define __CAST10(a,...) __CAST_TO_U64(a), __CAST9(__VA_ARGS__)
53 #define __CAST11(a,...) __CAST_TO_U64(a), __CAST10(__VA_ARGS__)
54 #define __CAST12(a,...) __CAST_TO_U64(a), __CAST11(__VA_ARGS__)
55 /* tracepoints with more than 12 arguments will hit build error */
56 #define CAST_TO_U64(...) CONCATENATE(__CAST, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__)
57 
58 #undef DECLARE_EVENT_CLASS
59 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
60 static notrace void							\
61 __bpf_trace_##call(void *__data, proto)					\
62 {									\
63 	struct bpf_prog *prog = __data;					\
64 	CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(prog, CAST_TO_U64(args));	\
65 }
66 
67 /*
68  * This part is compiled out, it is only here as a build time check
69  * to make sure that if the tracepoint handling changes, the
70  * bpf probe will fail to compile unless it too is updated.
71  */
72 #define __DEFINE_EVENT(template, call, proto, args, size)		\
73 static inline void bpf_test_probe_##call(void)				\
74 {									\
75 	check_trace_callback_type_##call(__bpf_trace_##template);	\
76 }									\
77 typedef void (*btf_trace_##call)(void *__data, proto);			\
78 static union {								\
79 	struct bpf_raw_event_map event;					\
80 	btf_trace_##call handler;					\
81 } __bpf_trace_tp_map_##call __used					\
82 __attribute__((section("__bpf_raw_tp_map"))) = {			\
83 	.event = {							\
84 		.tp		= &__tracepoint_##call,			\
85 		.bpf_func	= __bpf_trace_##template,		\
86 		.num_args	= COUNT_ARGS(args),			\
87 		.writable_size	= size,					\
88 	},								\
89 };
90 
91 #define FIRST(x, ...) x
92 
93 #undef DEFINE_EVENT_WRITABLE
94 #define DEFINE_EVENT_WRITABLE(template, call, proto, args, size)	\
95 static inline void bpf_test_buffer_##call(void)				\
96 {									\
97 	/* BUILD_BUG_ON() is ignored if the code is completely eliminated, but \
98 	 * BUILD_BUG_ON_ZERO() uses a different mechanism that is not	\
99 	 * dead-code-eliminated.					\
100 	 */								\
101 	FIRST(proto);							\
102 	(void)BUILD_BUG_ON_ZERO(size != sizeof(*FIRST(args)));		\
103 }									\
104 __DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
105 
106 #undef DEFINE_EVENT
107 #define DEFINE_EVENT(template, call, proto, args)			\
108 	__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), 0)
109 
110 #undef DEFINE_EVENT_PRINT
111 #define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
112 	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
113 
114 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
115 
116 #undef DEFINE_EVENT_WRITABLE
117 #undef __DEFINE_EVENT
118 #undef FIRST
119 
120 #endif /* CONFIG_BPF_EVENTS */
121