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From: Dave Marchevsky <davemarchevsky@fb.com>
To: Andrii Nakryiko <andrii@kernel.org>,
	bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net
Cc: kernel-team@fb.com, Alan Maguire <alan.maguire@oracle.com>,
	Hengqi Chen <hengqi.chen@gmail.com>
Subject: Re: [PATCH v2 bpf-next 5/7] libbpf: add x86-specific USDT arg spec parsing logic
Date: Mon, 4 Apr 2022 01:07:25 -0400	[thread overview]
Message-ID: <d624afa2-25da-d417-68eb-5ef302b96ebf@fb.com> (raw)
In-Reply-To: <20220402002944.382019-6-andrii@kernel.org>

On 4/1/22 8:29 PM, Andrii Nakryiko wrote:   
> Add x86/x86_64-specific USDT argument specification parsing. Each
> architecture will require their own logic, as all this is arch-specific
> assembly-based notation. Architectures that libbpf doesn't support for
> USDTs will pr_warn() with specific error and return -ENOTSUP.
> 
> We use sscanf() as a very powerful and easy to use string parser. Those
> spaces in sscanf's format string mean "skip any whitespaces", which is
> pretty nifty (and somewhat little known) feature.
> 
> All this was tested on little-endian architecture, so bit shifts are
> probably off on big-endian, which our CI will hopefully prove.
> 
> Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---
>  tools/lib/bpf/usdt.c | 105 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 105 insertions(+)

Reviewed-by: Dave Marchevsky <davemarchevsky@fb.com>

  reply	other threads:[~2022-04-04  5:08 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-02  0:29 [PATCH v2 bpf-next 0/7] Add libbpf support for USDTs Andrii Nakryiko
2022-04-02  0:29 ` [PATCH v2 bpf-next 1/7] libbpf: add BPF-side of USDT support Andrii Nakryiko
2022-04-04  0:23   ` Dave Marchevsky
2022-04-04  3:55     ` Andrii Nakryiko
2022-04-02  0:29 ` [PATCH v2 bpf-next 2/7] libbpf: wire up USDT API and bpf_link integration Andrii Nakryiko
2022-04-04  3:12   ` Dave Marchevsky
2022-04-04  4:18     ` Andrii Nakryiko
2022-04-05  1:00       ` Dave Marchevsky
2022-04-05 23:41         ` Andrii Nakryiko
2022-04-02  0:29 ` [PATCH v2 bpf-next 3/7] libbpf: add USDT notes parsing and resolution logic Andrii Nakryiko
2022-04-02  0:29 ` [PATCH v2 bpf-next 4/7] libbpf: wire up spec management and other arch-independent USDT logic Andrii Nakryiko
2022-04-04 19:58   ` Dave Marchevsky
2022-04-04 22:21     ` Andrii Nakryiko
2022-04-02  0:29 ` [PATCH v2 bpf-next 5/7] libbpf: add x86-specific USDT arg spec parsing logic Andrii Nakryiko
2022-04-04  5:07   ` Dave Marchevsky [this message]
2022-04-02  0:29 ` [PATCH v2 bpf-next 6/7] selftests/bpf: add basic USDT selftests Andrii Nakryiko
2022-04-04  5:48   ` Dave Marchevsky
2022-04-02  0:29 ` [PATCH v2 bpf-next 7/7] selftests/bpf: add urandom_read shared lib and USDTs Andrii Nakryiko
2022-04-04 18:34   ` Dave Marchevsky

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