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Date: Mon, 21 Aug 2023 12:47:11 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Louis Peens <louis.peens@corigine.com>
Cc: Yonghong Song <yonghong.song@linux.dev>, Shubham Bansal
 <illusionist.neo@gmail.com>, Johan Almbladh
 <johan.almbladh@anyfinetworks.com>, Paul Burton <paulburton@kernel.org>,
 "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>, Michael Ellerman
 <mpe@ellerman.id.au>, Luke Nelson <luke.r.nels@gmail.com>, Xi Wang
 <xi.wang@gmail.com>, =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>,
 Ilya Leoshkevich <iii@linux.ibm.com>, Heiko Carstens <hca@linux.ibm.com>,
 Vasily Gorbik <gor@linux.ibm.com>, "David S. Miller" <davem@davemloft.net>,
 Wang YanQing <udknight@gmail.com>, Alexei Starovoitov <ast@kernel.org>,
 Daniel Borkmann <daniel@iogearbox.net>, Andrii Nakryiko
 <andrii@kernel.org>, Martin KaFai Lau <martin.lau@kernel.org>, bpf
 <bpf@vger.kernel.org>
Subject: Re: bpf: Request to add -mcpu=v4 support for
 ARM/MIPS/NFP/POWERPC/RISCV/S390/SPARC/X86_32
Message-ID: <20230821124711.15babfee@kernel.org>
In-Reply-To: <79d3c797-17ba-bc9e-b1f9-44ad024b576f@linux.dev>
References: <79d3c797-17ba-bc9e-b1f9-44ad024b576f@linux.dev>
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On Sat, 19 Aug 2023 18:41:30 -0700 Yonghong Song wrote:
> Hi,
> 
> A new set of bpf insns have been recently added in llvm with flag
> [-mcpu=v4](https://reviews.llvm.org/D144829). In the kernel,
> x86_64 and arm64 have implemented -mcpu=v4 support:
>    x86_64: 
> https://lore.kernel.org/all/20230728011143.3710005-1-yonghong.song@linux.dev/
>    arm64: 
> https://lore.kernel.org/bpf/20230815154158.717901-1-xukuohai@huaweicloud.com/
> 
> The following arch's do not have -mcpu=v4 support yet:
>    arm, mips, nfp, powerpc, riscv, sc90, sparc and x86_32
> 
> If you have a chance, could you take a look at what
> x86_64/arm64 does and add support to the above arch'es?

Louis, is anyone on your side still working on BPF for NFP?
div/mod and the jump will be impossible but there may be instructions
for sign extend or bswap?