linux/include/trace/bpf_probe.h
Alexei Starovoitov e8c423fb31 bpf: Add typecast to raw_tracepoints to help BTF generation
When pahole converts dwarf to btf it emits only used types.
Wrap existing __bpf_trace_##template() function into
btf_trace_##template typedef and use it in type cast to
make gcc emits this type into dwarf. Then pahole will convert it to btf.
The "btf_trace_" prefix will be used to identify BTF enabled raw tracepoints.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20191016032505.2089704-2-ast@kernel.org
2019-10-17 16:44:35 +02:00

117 lines
3.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#undef TRACE_SYSTEM_VAR
#ifdef CONFIG_BPF_EVENTS
#undef __entry
#define __entry entry
#undef __get_dynamic_array
#define __get_dynamic_array(field) \
((void *)__entry + (__entry->__data_loc_##field & 0xffff))
#undef __get_dynamic_array_len
#define __get_dynamic_array_len(field) \
((__entry->__data_loc_##field >> 16) & 0xffff)
#undef __get_str
#define __get_str(field) ((char *)__get_dynamic_array(field))
#undef __get_bitmask
#define __get_bitmask(field) (char *)__get_dynamic_array(field)
#undef __perf_count
#define __perf_count(c) (c)
#undef __perf_task
#define __perf_task(t) (t)
/* cast any integer, pointer, or small struct to u64 */
#define UINTTYPE(size) \
__typeof__(__builtin_choose_expr(size == 1, (u8)1, \
__builtin_choose_expr(size == 2, (u16)2, \
__builtin_choose_expr(size == 4, (u32)3, \
__builtin_choose_expr(size == 8, (u64)4, \
(void)5)))))
#define __CAST_TO_U64(x) ({ \
typeof(x) __src = (x); \
UINTTYPE(sizeof(x)) __dst; \
memcpy(&__dst, &__src, sizeof(__dst)); \
(u64)__dst; })
#define __CAST1(a,...) __CAST_TO_U64(a)
#define __CAST2(a,...) __CAST_TO_U64(a), __CAST1(__VA_ARGS__)
#define __CAST3(a,...) __CAST_TO_U64(a), __CAST2(__VA_ARGS__)
#define __CAST4(a,...) __CAST_TO_U64(a), __CAST3(__VA_ARGS__)
#define __CAST5(a,...) __CAST_TO_U64(a), __CAST4(__VA_ARGS__)
#define __CAST6(a,...) __CAST_TO_U64(a), __CAST5(__VA_ARGS__)
#define __CAST7(a,...) __CAST_TO_U64(a), __CAST6(__VA_ARGS__)
#define __CAST8(a,...) __CAST_TO_U64(a), __CAST7(__VA_ARGS__)
#define __CAST9(a,...) __CAST_TO_U64(a), __CAST8(__VA_ARGS__)
#define __CAST10(a,...) __CAST_TO_U64(a), __CAST9(__VA_ARGS__)
#define __CAST11(a,...) __CAST_TO_U64(a), __CAST10(__VA_ARGS__)
#define __CAST12(a,...) __CAST_TO_U64(a), __CAST11(__VA_ARGS__)
/* tracepoints with more than 12 arguments will hit build error */
#define CAST_TO_U64(...) CONCATENATE(__CAST, COUNT_ARGS(__VA_ARGS__))(__VA_ARGS__)
#undef DECLARE_EVENT_CLASS
#define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \
static notrace void \
__bpf_trace_##call(void *__data, proto) \
{ \
struct bpf_prog *prog = __data; \
CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(prog, CAST_TO_U64(args)); \
}
/*
* This part is compiled out, it is only here as a build time check
* to make sure that if the tracepoint handling changes, the
* bpf probe will fail to compile unless it too is updated.
*/
#define __DEFINE_EVENT(template, call, proto, args, size) \
static inline void bpf_test_probe_##call(void) \
{ \
check_trace_callback_type_##call(__bpf_trace_##template); \
} \
typedef void (*btf_trace_##call)(void *__data, proto); \
static struct bpf_raw_event_map __used \
__attribute__((section("__bpf_raw_tp_map"))) \
__bpf_trace_tp_map_##call = { \
.tp = &__tracepoint_##call, \
.bpf_func = (void *)(btf_trace_##call)__bpf_trace_##template, \
.num_args = COUNT_ARGS(args), \
.writable_size = size, \
};
#define FIRST(x, ...) x
#undef DEFINE_EVENT_WRITABLE
#define DEFINE_EVENT_WRITABLE(template, call, proto, args, size) \
static inline void bpf_test_buffer_##call(void) \
{ \
/* BUILD_BUG_ON() is ignored if the code is completely eliminated, but \
* BUILD_BUG_ON_ZERO() uses a different mechanism that is not \
* dead-code-eliminated. \
*/ \
FIRST(proto); \
(void)BUILD_BUG_ON_ZERO(size != sizeof(*FIRST(args))); \
} \
__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
#undef DEFINE_EVENT
#define DEFINE_EVENT(template, call, proto, args) \
__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), 0)
#undef DEFINE_EVENT_PRINT
#define DEFINE_EVENT_PRINT(template, name, proto, args, print) \
DEFINE_EVENT(template, name, PARAMS(proto), PARAMS(args))
#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
#undef DEFINE_EVENT_WRITABLE
#undef __DEFINE_EVENT
#undef FIRST
#endif /* CONFIG_BPF_EVENTS */