From: Yonghong Song <yhs@fb.com>
To: Hou Tao <houtao1@huawei.com>, Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
<bpf@vger.kernel.org>, <netdev@vger.kernel.org>
Subject: Re: [PATCH 1/3] bpf: support writable context for bare tracepoint
Date: Thu, 16 Sep 2021 16:16:58 -0700 [thread overview]
Message-ID: <9cbbb8b4-f3e3-cd2d-a1cc-e086e7d28946@fb.com> (raw)
In-Reply-To: <20210916135511.3787194-2-houtao1@huawei.com>
On 9/16/21 6:55 AM, Hou Tao 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@huawei.com>
> ---
> 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..d08ee1060d82 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) \
> @@ -119,10 +122,18 @@ __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 DEFINE_EVENT_WRITABLE
> +#undef DECLARE_TRACE_WRITABLE
> #undef __DEFINE_EVENT
> +#undef __CHECK_WRITABLE_BUF_SIZE
Put "#undef __CHECK_WRITABLE_BUF_SIZE" right after "#undef
DECLARE_TRACE_WRITABLE" since they are related to each other
and also they are in correct reverse order w.r.t. __DEFINE_EVENT?
> #undef FIRST
>
> #endif /* CONFIG_BPF_EVENTS */
>
next prev parent reply other threads:[~2021-09-16 23:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-16 13:55 [PATCH 0/3] add support for writable bare tracepoint Hou Tao
2021-09-16 13:55 ` [PATCH 1/3] bpf: support writable context for " Hou Tao
2021-09-16 23:16 ` Yonghong Song [this message]
2021-09-17 13:45 ` Hou Tao
2021-09-17 14:48 ` Yonghong Song
2021-09-16 13:55 ` [PATCH 2/3] libbpf: support detecting and attaching of writable tracepoint program Hou Tao
2021-09-16 23:35 ` Yonghong Song
2021-09-16 13:55 ` [PATCH 3/3] bpf/selftests: add test for writable bare tracepoint Hou Tao
2021-09-16 23:46 ` Yonghong Song
2021-09-17 14:03 ` Hou Tao
2021-09-16 22:58 ` [PATCH 0/3] add support " Yonghong Song
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