On Thu, Sep 30, 2021 at 2:00 AM Hou Tao <houtao1@xxxxxxxxxx> wrote:
>
> Commit 9df1c28bb752 ("bpf: add writable context for raw tracepoints")
> supports writable context for tracepoint, but it misses the support
> for bare tracepoint which has no associated trace event.
>
> Bare tracepoint is defined by DECLARE_TRACE(), so adding a corresponding
> DECLARE_TRACE_WRITABLE() macro to generate a definition in __bpf_raw_tp_map
> section for bare tracepoint in a similar way to DEFINE_TRACE_WRITABLE().
>
> Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
> ---
LGTM.
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> include/trace/bpf_probe.h | 19 +++++++++++++++----
> 1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
> index a23be89119aa..a8e97f84b652 100644
> --- a/include/trace/bpf_probe.h
> +++ b/include/trace/bpf_probe.h
> @@ -93,8 +93,7 @@ __section("__bpf_raw_tp_map") = { \
>
> #define FIRST(x, ...) x
>
> -#undef DEFINE_EVENT_WRITABLE
> -#define DEFINE_EVENT_WRITABLE(template, call, proto, args, size) \
> +#define __CHECK_WRITABLE_BUF_SIZE(call, proto, args, size) \
> static inline void bpf_test_buffer_##call(void) \
> { \
> /* BUILD_BUG_ON() is ignored if the code is completely eliminated, but \
> @@ -103,8 +102,12 @@ static inline void bpf_test_buffer_##call(void) \
> */ \
> FIRST(proto); \
> (void)BUILD_BUG_ON_ZERO(size != sizeof(*FIRST(args))); \
> -} \
> -__DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
> +}
> +
> +#undef DEFINE_EVENT_WRITABLE
> +#define DEFINE_EVENT_WRITABLE(template, call, proto, args, size) \
> + __CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
> + __DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
>
> #undef DEFINE_EVENT
> #define DEFINE_EVENT(template, call, proto, args) \
> @@ -119,9 +122,17 @@ __DEFINE_EVENT(template, call, PARAMS(proto), PARAMS(args), size)
> __BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args)) \
> __DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), 0)
>
> +#undef DECLARE_TRACE_WRITABLE
> +#define DECLARE_TRACE_WRITABLE(call, proto, args, size) \
> + __CHECK_WRITABLE_BUF_SIZE(call, PARAMS(proto), PARAMS(args), size) \
> + __BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args)) \
> + __DEFINE_EVENT(call, call, PARAMS(proto), PARAMS(args), size)
> +
> #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
>
> +#undef DECLARE_TRACE_WRITABLE
> #undef DEFINE_EVENT_WRITABLE
> +#undef __CHECK_WRITABLE_BUF_SIZE
> #undef __DEFINE_EVENT
> #undef FIRST
>
> --
> 2.29.2
>
