From: "Björn Töpel" <bjorn.topel@gmail.com>
To: Paul Chaignon <paul.chaignon@orange.com>
Cc: Song Liu <songliubraving@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
Paul Burton <paulburton@kernel.org>,
paul.chaignon@gmail.com, Netdev <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
linux-riscv@lists.infradead.org, Martin KaFai Lau <kafai@fb.com>,
Yonghong Song <yhs@fb.com>,
Mahshid Khezri <khezri.mahshid@gmail.com>,
Andrii Nakryiko <andriin@fb.com>, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf 1/2] bpf, riscv: limit to 33 tail calls
Date: Tue, 10 Dec 2019 07:31:26 +0100 [thread overview]
Message-ID: <CAJ+HfNiqtF9T-C7a1NoSekSAW+Fpr2kH2EghLDiRmf_+-Uat-w@mail.gmail.com> (raw)
In-Reply-To: <CAJ+HfNgFo8viKn3KzNfbmniPNUpjOv_QM4ua_V0RFLBpWCOBYw@mail.gmail.com>
On Mon, 9 Dec 2019 at 20:57, Björn Töpel <bjorn.topel@gmail.com> wrote:
>
> On Mon, 9 Dec 2019 at 19:52, Paul Chaignon <paul.chaignon@orange.com> wrote:
> >
> > All BPF JIT compilers except RISC-V's and MIPS' enforce a 33-tail calls
> > limit at runtime. In addition, a test was recently added, in tailcalls2,
> > to check this limit.
> >
> > This patch updates the tail call limit in RISC-V's JIT compiler to allow
> > 33 tail calls. I tested it using the above selftest on an emulated
> > RISCV64.
> >
>
> 33! ICK! ;-) Thanks for finding this!
>
> Acked-by: Björn Töpel <bjorn.topel@gmail.com>
>
...and somewhat related; One of the tailcall tests fail due to missing
far-branch support in the emitter. I'll address this in the v2 of the
"far branch" series.
next prev parent reply other threads:[~2019-12-10 6:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1575916815.git.paul.chaignon@gmail.com>
[not found] ` <966fe384383bf23a0ee1efe8d7291c78a3fb832b.1575916815.git.paul.chaignon@gmail.com>
2019-12-09 19:57 ` [PATCH bpf 1/2] bpf, riscv: limit to 33 tail calls Björn Töpel
2019-12-10 6:31 ` Björn Töpel [this message]
2019-12-10 9:36 ` Paul Chaignon
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