xref: /linux/include/trace/bpf_probe.h (revision 056e065a6b6e01ab54bb9770c0d5a15350e571e2)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 #undef TRACE_SYSTEM_VAR
4 
5 #ifdef CONFIG_BPF_EVENTS
6 
7 #include "stages/stage6_event_callback.h"
8 
9 #undef __perf_count
10 #define __perf_count(c)	(c)
11 
12 #undef __perf_task
13 #define __perf_task(t)	(t)
14 
15 #include <linux/args.h>
16 
17 /* cast any integer, pointer, or small struct to u64 */
18 #define UINTTYPE(size) \
19 	__typeof__(__builtin_choose_expr(size == 1,  (u8)1, \
20 		   __builtin_choose_expr(size == 2, (u16)2, \
21 		   __builtin_choose_expr(size == 4, (u32)3, \
22 		   __builtin_choose_expr(size == 8, (u64)4, \
23 					 (void)5)))))
24 #define __CAST_TO_U64(x) ({ \
25 	typeof(x) __src = (x); \
26 	UINTTYPE(sizeof(x)) __dst; \
27 	memcpy(&__dst, &__src, sizeof(__dst)); \
28 	(u64)__dst; })
29 
30 #define __CAST1(a,...) __CAST_TO_U64(a)
31 #define __CAST2(a,...) __CAST_TO_U64(a), __CAST1(__VA_ARGS__)
32 #define __CAST3(a,...) __CAST_TO_U64(a), __CAST2(__VA_ARGS__)
33 #define __CAST4(a,...) __CAST_TO_U64(a), __CAST3(__VA_ARGS__)
34 #define __CAST5(a,...) __CAST_TO_U64(a), __CAST4(__VA_ARGS__)
35 #define __CAST6(a,...) __CAST_TO_U64(a), __CAST5(__VA_ARGS__)
36 #define __CAST7(a,...) __CAST_TO_U64(a), __CAST6(__VA_ARGS__)
37 #define __CAST8(a,...) __CAST_TO_U64(a), __CAST7(__VA_ARGS__)
38 #define __CAST9(a,...) __CAST_TO_U64(a), __CAST8(__VA_ARGS__)
39 #define __CAST10(a,...) __CAST_TO_U64(a), __CAST9(__VA_ARGS__)
40 #define __CAST11(a,...) __CAST_TO_U64(a), __CAST10(__VA_ARGS__)
41 #define __CAST12(a,...) __CAST_TO_U64(a), __CAST11(__VA_ARGS__)
42 /* tracepoints with more than 12 arguments will hit build error */
43 #define CAST_TO_U64(...) CONCATENATE(__CAST, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__)
44 
45 #define __BPF_DECLARE_TRACE(call, proto, args)				\
46 static notrace void							\
47 __bpf_trace_##call(void *__data, proto)					\
48 {									\
49 	CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(__data, CAST_TO_U64(args));	\
50 }
51 
52 #undef DECLARE_EVENT_CLASS
53 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
54 	__BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))
55 
56 #define __BPF_DECLARE_TRACE_SYSCALL(call, proto, args)			\
57 static notrace void							\
58 __bpf_trace_##call(void *__data, proto)					\
59 {									\
60 	might_fault();							\
61 	CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(__data, CAST_TO_U64(args));	\
62 }
63 
64 #undef DECLARE_EVENT_SYSCALL_CLASS
65 #define DECLARE_EVENT_SYSCALL_CLASS(call, proto, args, tstruct, assign, print)	\
66 	__BPF_DECLARE_TRACE_SYSCALL(call, PARAMS(proto), PARAMS(args))
67 
68 /*
69  * This part is compiled out, it is only here as a build time check
70  * to make sure that if the tracepoint handling changes, the
71  * bpf probe will fail to compile unless it too is updated.
72  */
73 #define __DEFINE_EVENT(template, call, proto, args, size)		\
74 static inline void bpf_test_probe_##call(void)				\
75 {									\
76 	check_trace_callback_type_##call(__bpf_trace_##template);	\
77 }									\
78 typedef void (*btf_trace_##call)(void *__data, proto);			\
79 static union {								\
80 	struct bpf_raw_event_map event;					\
81 	btf_trace_##call handler;					\
82 } __bpf_trace_tp_map_##call __used					\
83 __section("__bpf_raw_tp_map") = {					\
84 	.event = {							\
85 		.tp		= &__tracepoint_##call,			\
86 		.bpf_func	= __bpf_trace_##template,		\
87 		.num_args	= COUNT_ARGS(args),			\
88 		.writable_size	= size,					\
89 	},								\
90 };
91 
92 #define FIRST(x, ...) x
93 
94 #define __CHECK_WRITABLE_BUF_SIZE(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 
105 #undef DEFINE_EVENT_WRITABLE
106 #define DEFINE_EVENT_WRITABLE(template, call, proto, args, size) \
107 	__CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
108 	__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
109 
110 #undef DEFINE_EVENT
111 #define DEFINE_EVENT(template, call, proto, args)			\
112 	__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), 0)
113 
114 #undef DEFINE_EVENT_PRINT
115 #define DEFINE_EVENT_PRINT(template, name, proto, args, print)	\
116 	DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
117 
118 #undef DECLARE_TRACE
119 #define DECLARE_TRACE(call, proto, args)				\
120 	__BPF_DECLARE_TRACE(call##_tp, PARAMS(proto), PARAMS(args))		\
121 	__DEFINE_EVENT(call##_tp, call##_tp, PARAMS(proto), PARAMS(args), 0)
122 
123 #undef DECLARE_TRACE_WRITABLE
124 #define DECLARE_TRACE_WRITABLE(call, proto, args, size) \
125 	__CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
126 	__BPF_DECLARE_TRACE(call##_tp, PARAMS(proto), PARAMS(args)) \
127 	__DEFINE_EVENT(call##_tp, call##_tp, PARAMS(proto), PARAMS(args), size)
128 
129 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
130 
131 #undef DECLARE_TRACE_WRITABLE
132 #undef DEFINE_EVENT_WRITABLE
133 #undef __CHECK_WRITABLE_BUF_SIZE
134 #undef __DEFINE_EVENT
135 #undef FIRST
136 
137 #endif /* CONFIG_BPF_EVENTS */
138