bpf_probe.h

   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         struct bpf_prog *prog = __data;                                 \
  50         CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(prog, CAST_TO_U64(args));  \
  51 }
  52
  53 #undef DECLARE_EVENT_CLASS
  54 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)  \
  55         __BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))
  56
  57 /*
  58  * This part is compiled out, it is only here as a build time check
  59  * to make sure that if the tracepoint handling changes, the
  60  * bpf probe will fail to compile unless it too is updated.
  61  */
  62 #define __DEFINE_EVENT(template, call, proto, args, size)               \
  63 static inline void bpf_test_probe_##call(void)                          \
  64 {                                                                       \
  65         check_trace_callback_type_##call(__bpf_trace_##template);       \
  66 }                                                                       \
  67 typedef void (*btf_trace_##call)(void *__data, proto);                  \
  68 static union {                                                          \
  69         struct bpf_raw_event_map event;                                 \
  70         btf_trace_##call handler;                                       \
  71 } __bpf_trace_tp_map_##call __used                                      \
  72 __section("__bpf_raw_tp_map") = {                                       \
  73         .event = {                                                      \
  74                 .tp             = &__tracepoint_##call,                 \
  75                 .bpf_func       = __bpf_trace_##template,               \
  76                 .num_args       = COUNT_ARGS(args),                     \
  77                 .writable_size  = size,                                 \
  78         },                                                              \
  79 };
  80
  81 #define FIRST(x, ...) x
  82
  83 #define __CHECK_WRITABLE_BUF_SIZE(call, proto, args, size)              \
  84 static inline void bpf_test_buffer_##call(void)                         \
  85 {                                                                       \
  86         /* BUILD_BUG_ON() is ignored if the code is completely eliminated, but \
  87          * BUILD_BUG_ON_ZERO() uses a different mechanism that is not   \
  88          * dead-code-eliminated.                                        \
  89          */                                                             \
  90         FIRST(proto);                                                   \
  91         (void)BUILD_BUG_ON_ZERO(size != sizeof(*FIRST(args)));          \
  92 }
  93
  94 #undef DEFINE_EVENT_WRITABLE
  95 #define DEFINE_EVENT_WRITABLE(template, call, proto, args, size) \
  96         __CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
  97         __DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
  98
  99 #undef DEFINE_EVENT
 100 #define DEFINE_EVENT(template, call, proto, args)                       \
 101         __DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), 0)
 102
 103 #undef DEFINE_EVENT_PRINT
 104 #define DEFINE_EVENT_PRINT(template, name, proto, args, print)  \
 105         DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
 106
 107 #undef DECLARE_TRACE
 108 #define DECLARE_TRACE(call, proto, args)                                \
 109         __BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))          \
 110         __DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), 0)
 111
 112 #undef DECLARE_TRACE_WRITABLE
 113 #define DECLARE_TRACE_WRITABLE(call, proto, args, size) \
 114         __CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
 115         __BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args)) \
 116         __DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), size)
 117
 118 #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
 119
 120 #undef DECLARE_TRACE_WRITABLE
 121 #undef DEFINE_EVENT_WRITABLE
 122 #undef __CHECK_WRITABLE_BUF_SIZE
 123 #undef __DEFINE_EVENT
 124 #undef FIRST
 125
 126 #endif /* CONFIG_BPF_EVENTS */