netdev - Re: [PATCH bpf-next 3/6] riscv, bpf: Simplify sext and zext logics in branch instructions

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Message-ID: <20230916144742.GB1125562@kernel.org>
Date: Sat, 16 Sep 2023 16:47:42 +0200
From: Simon Horman <horms@...nel.org>
To: Pu Lehui <pulehui@...weicloud.com>
Cc: bpf@...r.kernel.org, linux-riscv@...ts.infradead.org,
	netdev@...r.kernel.org,
	Björn Töpel <bjorn@...nel.org>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>, Song Liu <song@...nel.org>,
	Yonghong Song <yhs@...com>,
	John Fastabend <john.fastabend@...il.com>,
	KP Singh <kpsingh@...nel.org>, Stanislav Fomichev <sdf@...gle.com>,
	Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
	Palmer Dabbelt <palmer@...belt.com>,
	Luke Nelson <luke.r.nels@...il.com>, Pu Lehui <pulehui@...wei.com>
Subject: Re: [PATCH bpf-next 3/6] riscv, bpf: Simplify sext and zext logics
 in branch instructions

On Wed, Sep 13, 2023 at 11:34:10PM +0800, Pu Lehui wrote:
> From: Pu Lehui <pulehui@...wei.com>
> 
> There are many extension helpers in the current branch instructions, and
> the implementation is a bit complicated. We simplify this logic through
> two simple extension helpers with alternate register.
> 
> Signed-off-by: Pu Lehui <pulehui@...wei.com>
> ---
>  arch/riscv/net/bpf_jit_comp64.c | 82 +++++++++++++--------------------
>  1 file changed, 31 insertions(+), 51 deletions(-)
> 
> diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c
> index 4a649e195..1728ce16d 100644
> --- a/arch/riscv/net/bpf_jit_comp64.c
> +++ b/arch/riscv/net/bpf_jit_comp64.c
> @@ -141,6 +141,19 @@ static bool in_auipc_jalr_range(s64 val)
>  		val < ((1L << 31) - (1L << 11));
>  }
>  
> +/* Modify rd pointer to alternate reg to avoid corrupting orignal reg */

Hi Pu Lehui,

nit: original

I suggest running checkpatch --codespell over this series before submitting
v2.