xref: /openbmc/linux/include/trace/bpf_probe.h (revision 94d964e5)
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 __get_rel_dynamic_array
25 #define __get_rel_dynamic_array(field)	\
26 		((void *)(&__entry->__rel_loc_##field) +	\
27 		 sizeof(__entry->__rel_loc_##field) +		\
28 		 (__entry->__rel_loc_##field & 0xffff))
29 
30 #undef __get_rel_dynamic_array_len
31 #define __get_rel_dynamic_array_len(field)	\
32 		((__entry->__rel_loc_##field >> 16) & 0xffff)
33 
34 #undef __get_rel_str
35 #define __get_rel_str(field) ((char *)__get_rel_dynamic_array(field))
36 
37 #undef __get_rel_bitmask
38 #define __get_rel_bitmask(field) (char *)__get_rel_dynamic_array(field)
39 
40 #undef __perf_count
41 #define __perf_count(c)	(c)
42 
43 #undef __perf_task
44 #define __perf_task(t)	(t)
45 
46 /* cast any integer, pointer, or small struct to u64 */
47 #define UINTTYPE(size) \
48 	__typeof__(__builtin_choose_expr(size == 1,  (u8)1, \
49 		   __builtin_choose_expr(size == 2, (u16)2, \
50 		   __builtin_choose_expr(size == 4, (u32)3, \
51 		   __builtin_choose_expr(size == 8, (u64)4, \
52 					 (void)5)))))
53 #define __CAST_TO_U64(x) ({ \
54 	typeof(x) __src = (x); \
55 	UINTTYPE(sizeof(x)) __dst; \
56 	memcpy(&__dst, &__src, sizeof(__dst)); \
57 	(u64)__dst; })
58 
59 #define __CAST1(a,...) __CAST_TO_U64(a)
60 #define __CAST2(a,...) __CAST_TO_U64(a), __CAST1(__VA_ARGS__)
61 #define __CAST3(a,...) __CAST_TO_U64(a), __CAST2(__VA_ARGS__)
62 #define __CAST4(a,...) __CAST_TO_U64(a), __CAST3(__VA_ARGS__)
63 #define __CAST5(a,...) __CAST_TO_U64(a), __CAST4(__VA_ARGS__)
64 #define __CAST6(a,...) __CAST_TO_U64(a), __CAST5(__VA_ARGS__)
65 #define __CAST7(a,...) __CAST_TO_U64(a), __CAST6(__VA_ARGS__)
66 #define __CAST8(a,...) __CAST_TO_U64(a), __CAST7(__VA_ARGS__)
67 #define __CAST9(a,...) __CAST_TO_U64(a), __CAST8(__VA_ARGS__)
68 #define __CAST10(a,...) __CAST_TO_U64(a), __CAST9(__VA_ARGS__)
69 #define __CAST11(a,...) __CAST_TO_U64(a), __CAST10(__VA_ARGS__)
70 #define __CAST12(a,...) __CAST_TO_U64(a), __CAST11(__VA_ARGS__)
71 /* tracepoints with more than 12 arguments will hit build error */
72 #define CAST_TO_U64(...) CONCATENATE(__CAST, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__)
73 
74 #define __BPF_DECLARE_TRACE(call, proto, args)				\
75 static notrace void							\
76 __bpf_trace_##call(void *__data, proto)					\
77 {									\
78 	struct bpf_prog *prog = __data;					\
79 	CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(prog, CAST_TO_U64(args));	\
80 }
81 
82 #undef DECLARE_EVENT_CLASS
83 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
84 	__BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))
85 
86 /*
87  * This part is compiled out, it is only here as a build time check
88  * to make sure that if the tracepoint handling changes, the
89  * bpf probe will fail to compile unless it too is updated.
90  */
91 #define __DEFINE_EVENT(template, call, proto, args, size)		\
92 static inline void bpf_test_probe_##call(void)				\
93 {									\
94 	check_trace_callback_type_##call(__bpf_trace_##template);	\
95 }									\
96 typedef void (*btf_trace_##call)(void *__data, proto);			\
97 static union {								\
98 	struct bpf_raw_event_map event;					\
99 	btf_trace_##call handler;					\
100 } __bpf_trace_tp_map_##call __used					\
101 __section("__bpf_raw_tp_map") = {					\
102 	.event = {							\
103 		.tp		= &__tracepoint_##call,			\
104 		.bpf_func	= __bpf_trace_##template,		\
105 		.num_args	= COUNT_ARGS(args),			\
106 		.writable_size	= size,					\
107 	},								\
108 };
109 
110 #define FIRST(x, ...) x
111 
112 #define __CHECK_WRITABLE_BUF_SIZE(call, proto, args, size)		\
113 static inline void bpf_test_buffer_##call(void)				\
114 {									\
115 	/* BUILD_BUG_ON() is ignored if the code is completely eliminated, but \
116 	 * BUILD_BUG_ON_ZERO() uses a different mechanism that is not	\
117 	 * dead-code-eliminated.					\
118 	 */								\
119 	FIRST(proto);							\
120 	(void)BUILD_BUG_ON_ZERO(size != sizeof(*FIRST(args)));		\
121 }
122 
123 #undef DEFINE_EVENT_WRITABLE
124 #define DEFINE_EVENT_WRITABLE(template, call, proto, args, size) \
125 	__CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
126 	__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
127 
128 #undef DEFINE_EVENT
129 #define DEFINE_EVENT(template, call, proto, args)			\
130 	__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), 0)
131 
132 #undef DEFINE_EVENT_PRINT
133 #define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
134 	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
135 
136 #undef DECLARE_TRACE
137 #define DECLARE_TRACE(call, proto, args)				\
138 	__BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))		\
139 	__DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), 0)
140 
141 #undef DECLARE_TRACE_WRITABLE
142 #define DECLARE_TRACE_WRITABLE(call, proto, args, size) \
143 	__CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
144 	__BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args)) \
145 	__DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), size)
146 
147 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
148 
149 #undef DECLARE_TRACE_WRITABLE
150 #undef DEFINE_EVENT_WRITABLE
151 #undef __CHECK_WRITABLE_BUF_SIZE
152 #undef __DEFINE_EVENT
153 #undef FIRST
154 
155 #endif /* CONFIG_BPF_EVENTS */
156