unimore/kernel-hacking-2024-linux-steffo
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bpf: Add typecast to raw_tracepoints to help BTF generation

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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
This commit is contained in:
Alexei Starovoitov 2019-10-15 20:24:55 -07:00 committed by Daniel Borkmann
parent eac9153f2b
commit e8c423fb31
1 changed files with 2 additions and 1 deletions
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3
include/trace/bpf_probe.h
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@ -74,11 +74,12 @@ 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 *)__bpf_trace_##template, \
.bpf_func = (void *)(btf_trace_##call)__bpf_trace_##template, \
.num_args = COUNT_ARGS(args), \
.writable_size = size, \
};