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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: David Vernet <void@manifault.com>
Cc: Dave Thaler <dthaler1968@googlemail.com>,
	bpf@ietf.org, bpf <bpf@vger.kernel.org>,
	 "Jose E. Marchesi" <jose.marchesi@oracle.com>
Subject: Re: [Bpf] Standardizing BPF assembly language?
Date: Wed, 24 Jan 2024 18:51:16 -0800	[thread overview]
Message-ID: <CAADnVQLFc+32+5yTrONYhw-HGheYRK2nSEgMoteXdwc_Q2Tw1Q@mail.gmail.com> (raw)
In-Reply-To: <20240123215214.GC221862@maniforge>

On Tue, Jan 23, 2024 at 1:52 PM David Vernet <void@manifault.com> wrote:
> > > > A second question would be, which dialect(s) to standardize.  Jose's
> > > > link above argues that the second dialect should be the one
> > > > standardized (tools are free to support multiple dialects for
> > > > backwards compat if they want).  See the link for rationale.
> > >
> > > My recollection was that the outcome of that discussion is that we were
> > going
> > > to continue to support both. If we wanted to standardize, I have a hard
> > time
> > > seeing any other way other than to standardize both dialects unless
> > there's
> > > been a significant change in sentiment since LSFMM.
> >
> > If "standardize both", does that mean neither is mandatory and each tool
> > is free to pick one or the other?  And would the IANA registry require a
> > document
> > adding any new instructions to specify the assembly in both dialects?
>
> Well, if we're standardizing on both, then yes I think it would be
> mandatory for a tool to support both, and I think instructions would
> require assembly for both dialects.

I think it's obvious that there is no way we will add gcc's flavor
of asm to kernel and llvm.

> Practically speaking that's already
> what's happening, no? Both dialects are already pervasive,

They are not. There are thousands of lines of asm written in pseudo-c
used in production applications and probably only ubpf/tests and gcc/tests
in that other asm, since gcc bpf support is not yet in the released gcc version.

There is also this asm flavor:
https://github.com/Xilinx-CNS/ebpf_asm

Which is different from pseudo-c and ubpf asm.

I don't think asm syntax should be an IETF draft.

WARNING: multiple messages have this Message-ID (diff)
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: David Vernet <void@manifault.com>
Cc: Dave Thaler <dthaler1968@googlemail.com>,
	bpf@ietf.org, bpf <bpf@vger.kernel.org>,
	"Jose E. Marchesi" <jose.marchesi@oracle.com>
Subject: Re: [Bpf] Standardizing BPF assembly language?
Date: Wed, 24 Jan 2024 18:51:16 -0800	[thread overview]
Message-ID: <CAADnVQLFc+32+5yTrONYhw-HGheYRK2nSEgMoteXdwc_Q2Tw1Q@mail.gmail.com> (raw)
Message-ID: <20240125025116.T28NJEB4nz5nzRf220YLVShIk2lqZA84alAUau75Vdo@z> (raw)
In-Reply-To: <20240123215214.GC221862@maniforge>

On Tue, Jan 23, 2024 at 1:52 PM David Vernet <void@manifault.com> wrote:
> > > > A second question would be, which dialect(s) to standardize.  Jose's
> > > > link above argues that the second dialect should be the one
> > > > standardized (tools are free to support multiple dialects for
> > > > backwards compat if they want).  See the link for rationale.
> > >
> > > My recollection was that the outcome of that discussion is that we were
> > going
> > > to continue to support both. If we wanted to standardize, I have a hard
> > time
> > > seeing any other way other than to standardize both dialects unless
> > there's
> > > been a significant change in sentiment since LSFMM.
> >
> > If "standardize both", does that mean neither is mandatory and each tool
> > is free to pick one or the other?  And would the IANA registry require a
> > document
> > adding any new instructions to specify the assembly in both dialects?
>
> Well, if we're standardizing on both, then yes I think it would be
> mandatory for a tool to support both, and I think instructions would
> require assembly for both dialects.

I think it's obvious that there is no way we will add gcc's flavor
of asm to kernel and llvm.

> Practically speaking that's already
> what's happening, no? Both dialects are already pervasive,

They are not. There are thousands of lines of asm written in pseudo-c
used in production applications and probably only ubpf/tests and gcc/tests
in that other asm, since gcc bpf support is not yet in the released gcc version.

There is also this asm flavor:
https://github.com/Xilinx-CNS/ebpf_asm

Which is different from pseudo-c and ubpf asm.

I don't think asm syntax should be an IETF draft.

-- 
Bpf mailing list
Bpf@ietf.org
https://www.ietf.org/mailman/listinfo/bpf

  parent reply	other threads:[~2024-01-25  2:51 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-23 16:45 Standardizing BPF assembly language? dthaler1968
2024-01-23 16:45 ` [Bpf] " dthaler1968=40googlemail.com
2024-01-23 21:31 ` David Vernet
2024-01-23 21:31   ` David Vernet
2024-01-23 21:41   ` dthaler1968
2024-01-23 21:41     ` dthaler1968=40googlemail.com
2024-01-23 21:52     ` David Vernet
2024-01-23 21:52       ` David Vernet
2024-01-23 23:15       ` dthaler1968
2024-01-23 23:15         ` dthaler1968=40googlemail.com
2024-01-25  2:51       ` Alexei Starovoitov [this message]
2024-01-25  2:51         ` Alexei Starovoitov
2024-01-27  5:29         ` David Vernet
2024-01-27  5:29           ` David Vernet
2024-01-25  3:13 ` Watson Ladd
2024-01-25  3:13   ` Watson Ladd

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