Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220926122727.2310118-1-yijun@loongson.cn>
In-Reply-To: <20220926122727.2310118-1-yijun@loongson.cn>
From:   Guo Ren <guoren@kernel.org>
Date:   Tue, 27 Sep 2022 07:41:12 +0800
Message-ID: <CAJF2gTQR804AwU0up2-FyTciQZJY2M9xQ7JbiqjwMbkD=aLhCQ@mail.gmail.com>
Subject: Re: [PATCH v3] LoongArch: Fixup do_ri csr_era
To:     Jun Yi <yijun@loongson.cn>
Cc:     Huacai Chen <chenhuacai@kernel.org>,
        WANG Xuerui <kernel@xen0n.name>,
        Tiezhu Yang <yangtiezhu@loongson.cn>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Qing Zhang <zhangqing@loongson.cn>,
        Mao Bibo <maobibo@loongson.cn>,
        Jianmin Lv <lvjianmin@loongson.cn>, loongarch@lists.linux.dev,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Mon, Sep 26, 2022 at 8:27 PM Jun Yi <yijun@loongson.cn> wrote:
>
> csr_era of pt_regs in do_ri should not add 4 to point to the
> next instruction.
The comment does not make sense. I think it wants to skip some
instructions, but your patch broke that.

>
> Signed-off-by: Jun Yi <yijun@loongson.cn>
> ---
>  arch/loongarch/kernel/traps.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
> index aa1c95aaf595..ec888eda3d45 100644
> --- a/arch/loongarch/kernel/traps.c
> +++ b/arch/loongarch/kernel/traps.c
> @@ -477,8 +477,6 @@ asmlinkage void noinstr do_ri(struct pt_regs *regs)
>
>         die_if_kernel("Reserved instruction in kernel code", regs);
>
> -       compute_return_era(regs);
> -
>         if (unlikely(get_user(opcode, era) < 0)) {
>                 status = SIGSEGV;
>                 current->thread.error_code = 1;
> --
> 2.31.1
>


-- 
Best Regards
 Guo Ren