From: Christoph Hellwig <hch@lst.de>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>, Jonathan Corbet <corbet@lwn.net>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
linux-doc@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org
Subject: Re: [PATCH 3/4] bpf, docs: Generate nicer tables for instruction encodings
Date: Mon, 3 Jan 2022 10:57:12 +0100 [thread overview]
Message-ID: <20220103095712.GA29880@lst.de> (raw)
In-Reply-To: <20211231004324.wvfqqgntnpswhzby@ast-mbp>
On Thu, Dec 30, 2021 at 04:43:24PM -0800, Alexei Starovoitov wrote:
> > + ======== ===== =========================
> > + code value description
> > + ======== ===== =========================
> > + BPF_JA 0x00 BPF_JMP only
> > BPF_JEQ 0x10
> > BPF_JGT 0x20
> > BPF_JGE 0x30
> > BPF_JSET 0x40
>
> Not your fault, but the new table looks odd with
> only some opcodes documented.
> Same issue with BPF_ALU table.
> In the past the documented opcodes were for eBPF only and
> not documented in both, so it wasn't that bad.
> At least there was a reason for discrepancy.
> Now it just odd.
> May be add a comment to all rows?
Yes, having the description everywhere would be good. But I'll have to
do research to actually figure out what should go in there for some.
> > + ============= ===== =====================
> > + mode modifier value description
> > + ============= ===== =====================
> > + BPF_IMM 0x00 used for 64-bit mov
> > + BPF_ABS 0x20
> > + BPF_IND 0x40
> > + BPF_MEM 0x60
>
> May be say here that ABS and IND are legacy for compat with classic only?
> and MEM is the most common modifier for load/store?
Sure.
next prev parent reply other threads:[~2022-01-03 9:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-23 10:19 improve the eBPF documentation v2 Christoph Hellwig
2021-12-23 10:19 ` [PATCH 1/4] bpf, docs: Fix verifier references Christoph Hellwig
2021-12-23 10:19 ` [PATCH 2/4] bpf, docs: Split the comparism to classic BPF from instruction-set.rst Christoph Hellwig
2021-12-23 10:19 ` [PATCH 3/4] bpf, docs: Generate nicer tables for instruction encodings Christoph Hellwig
2021-12-31 0:43 ` Alexei Starovoitov
2022-01-03 9:57 ` Christoph Hellwig [this message]
2021-12-23 10:19 ` [PATCH 4/4] bpf, docs: Move the packet access instructions last in instruction-set.rst Christoph Hellwig
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