From: Hou Tao <houtao1@huawei.com>
To: Yonghong Song <yhs@fb.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: Fri, 17 Sep 2021 21:45:44 +0800 [thread overview]
Message-ID: <b76d4051-abff-5e75-c812-41c6f283327f@huawei.com> (raw)
In-Reply-To: <9cbbb8b4-f3e3-cd2d-a1cc-e086e7d28946@fb.com>
Hi,
On 9/17/2021 7:16 AM, Yonghong Song wrote:
>
>
> 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?
If considering __CHECK_WRITABLE_BUF_SIZE is used in both DECLARE_TRACE_WRITABLE and
DEFINE_EVENT_WRITABLE and the order of definitions, is the following order better ?
#undef DECLARE_TRACE_WRITABLE
#undef DEFINE_EVENT_WRITABLE
#undef __CHECK_WRITABLE_BUF_SIZE
>
>> #undef FIRST
>> #endif /* CONFIG_BPF_EVENTS */
>>
> .
next prev parent reply other threads:[~2021-09-17 13:45 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
2021-09-17 13:45 ` Hou Tao [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=b76d4051-abff-5e75-c812-41c6f283327f@huawei.com \
--to=houtao1@huawei.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=kafai@fb.com \
--cc=netdev@vger.kernel.org \
--cc=songliubraving@fb.com \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox