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Date:   Sat, 9 Jul 2022 16:48:05 +0800
From:   Yixun Lan <dlan@gentoo.org>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     Yonghong Song <yhs@fb.com>,
        Andrii Nakryiko <andrii.nakryiko@gmail.com>,
        Alan Maguire <alan.maguire@oracle.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        linux-riscv@lists.infradead.org,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        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>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH] RISC-V/bpf: Enable bpf_probe_read{, str}()
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Hi Christoph:

On 23:24 Fri 08 Jul     , Christoph Hellwig wrote:
> On Sat, Jul 09, 2022 at 09:01:10AM +0800, Yixun Lan wrote:
> > Please check the ongoing discussion [0] in the bcc tools if you're
> > interested in, advice and comments are welcome
> > 
> > [0] https://github.com/iovisor/bcc/pull/4085#issuecomment-1179446738
> 
> I can't find a way to post there, as replying eems to require a login.
> Is there a mailing list discussion somewhere that is broadly accessible?

never mind, I think the logic is quite clear, we can do something in bcc:

1) adopt new _{kernel,user} interface whenever possible, this will
work fine for all arch with new kernel versions

2) for old kernel versions which lack the _{kernel,user} support,
fall back to old bpf_probe_read(), but take care of the Archs which
have overlaping address space - like s390, and just error out for it

-- 
Yixun Lan (dlan)
Gentoo Linux Developer
GPG Key ID AABEFD55