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Date: Mon, 25 Mar 2024 19:10:33 +0000
From: Conor Dooley <conor@kernel.org>
To: Puranjay Mohan <puranjay12@gmail.com>
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>,
	=?iso-8859-1?Q?Bj=F6rn_T=F6pel?= <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>
Subject: Re: [PATCH bpf-next v2 2/2] bpf,riscv: Implement bpf_addr_space_cast
 instruction
Message-ID: <20240325-nineteen-unvaried-cb5cb5fd3a73@spud>
References: <20240325155434.65589-1-puranjay12@gmail.com>
 <20240325155434.65589-3-puranjay12@gmail.com>
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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 as
> bpf_arena address space.
>=20
> rY =3D addr_space_cast(rX, 0, 1) is processed by the verifier and
> converted to normal 32-bit move: wX =3D wY
>=20
> rY =3D addr_space_cast(rX, 1, 0) has to be converted by JIT.
>=20
> 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 undeclared func=
tion 'insn_is_cast_user'; ISO C99 and later do not support implicit functio=
n declarations [-Wimplicit-function-declaration]

Cheers,
Conor.

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