Received-SPF: pass (google.com: domain of linux-kernel+bounces-117810-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Precedence: bulk
MIME-Version: 1.0
References: <20240325155434.65589-1-puranjay12@gmail.com> <20240325155434.65589-3-puranjay12@gmail.com>
 <20240325-nineteen-unvaried-cb5cb5fd3a73@spud> <CANk7y0gWtwN7EJ24aoY9-RB9629d5Ks-9fMc3wnAAjjERcZhFw@mail.gmail.com>
 <20240325-perpetual-liking-25f26e485b65@spud>
In-Reply-To: <20240325-perpetual-liking-25f26e485b65@spud>
From: Puranjay Mohan <puranjay12@gmail.com>
Date: Mon, 25 Mar 2024 20:23:18 +0100
Message-ID: <CANk7y0jtURUC6PWx5nSDigMpScUT+p3qd=hTtqJkCqAN+Nq32A@mail.gmail.com>
Subject: Re: [PATCH bpf-next v2 2/2] bpf,riscv: Implement bpf_addr_space_cast instruction
To: Conor Dooley <conor@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>, Daniel Borkmann <daniel@iogearbox.net>, 
	Andrii Nakryiko <andrii@kernel.org>, Martin KaFai Lau <martin.lau@linux.dev>, 
	Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>, 
	Yonghong Song <yonghong.song@linux.dev>, John Fastabend <john.fastabend@gmail.com>, 
	KP Singh <kpsingh@kernel.org>, Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>, 
	Jiri Olsa <jolsa@kernel.org>, =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>, 
	Luke Nelson <luke.r.nels@gmail.com>, Xi Wang <xi.wang@gmail.com>, 
	Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, 
	Albert Ou <aou@eecs.berkeley.edu>, bpf@vger.kernel.org, 
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, 
	Pu Lehui <pulehui@huaweicloud.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Mon, Mar 25, 2024 at 8:19=E2=80=AFPM Conor Dooley <conor@kernel.org> wro=
te:
>
> On Mon, Mar 25, 2024 at 08:13:10PM +0100, Puranjay Mohan wrote:
> > On Mon, Mar 25, 2024 at 8:10=E2=80=AFPM Conor Dooley <conor@kernel.org>=
 wrote:
> > >
> > > On Mon, Mar 25, 2024 at 03:54:34PM +0000, Puranjay Mohan wrote:
> > > > LLVM generates bpf_addr_space_cast instruction while translating
> > > > pointers between native (zero) address space and
> > > > __attribute__((address_space(N))). The addr_space=3D0 is reserved a=
s
> > > > bpf_arena address space.
> > > >
> > > > rY =3D addr_space_cast(rX, 0, 1) is processed by the verifier and
> > > > converted to normal 32-bit move: wX =3D wY
> > > >
> > > > rY =3D addr_space_cast(rX, 1, 0) has to be converted by JIT.
> > > >
> > > > Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>
> > >
> > > Doesn't compile for allmodconfig:
> > >   ../arch/riscv/net/bpf_jit_comp64.c:1086:7: error: call to undeclare=
d function 'insn_is_cast_user'; ISO C99 and later do not support implicit f=
unction declarations [-Wimplicit-function-declaration]
> > >
> > > Cheers,
> > > Conor.
> >
> > Yes,
> > I mentioned in the cover letter that a patch is required.
> > It just got merged in bpf-next/master:
> > https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git/commit=
/?id=3D770546ae9f4c1ae1ebcaf0874f0dd9631d77ec97
> >
> > So, rebasing on the latest bpf-next/master should fix the issue.
>
> Ah, I see now that there was a mention in the cover letter that I did
> not see first time around.
>
> Bjorn, do you think there's anything we can do about these kinda
> misleading CI failures for bpf stuff? Some stuff that touches bpf
> definitely is worth us building, but should we try and build it on top
> of the bpf tree instead?

Is there a separate CI for RISCV related stuff? is it public?

I would be interested in adding RISC-V support in
https://github.com/kernel-patches/bpf
Is someone already working on this?