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References: <20221010095346.1957-1-thunder.leizhen@huawei.com> <20221010095346.1957-2-thunder.leizhen@huawei.com>
In-Reply-To: <20221010095346.1957-2-thunder.leizhen@huawei.com>
From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Mon, 10 Oct 2022 12:20:35 +0200
Message-ID: <CAMj1kXHOv23JY35fZ45k=Pzi=ROd6BOCxqPkfXLh2520qhoFzQ@mail.gmail.com>
Subject: Re: [PATCH v2 1/2] ARM: Fix some check warnings of tool sparse
To:     Zhen Lei <thunder.leizhen@huawei.com>
Cc:     Russell King <linux@armlinux.org.uk>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
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On Mon, 10 Oct 2022 at 11:56, Zhen Lei <thunder.leizhen@huawei.com> wrote:
>
> Fix the following warnings:
>  warning: incorrect type in initializer (different address spaces)
>     expected unsigned short [noderef] __user *register __p
>     got unsigned short [usertype] *
>  warning: cast removes address space '__user' of expression
>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> ---
>  arch/arm/kernel/traps.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
> index 20b2db6dcd1ced7..34aa80c09c508c1 100644
> --- a/arch/arm/kernel/traps.c
> +++ b/arch/arm/kernel/traps.c
> @@ -188,9 +188,9 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
>                         }
>                 } else {
>                         if (thumb)
> -                               bad = get_user(val, &((u16 *)addr)[i]);
> +                               bad = get_user(val, &((u16 __user *)addr)[i]);
>                         else
> -                               bad = get_user(val, &((u32 *)addr)[i]);
> +                               bad = get_user(val, &((u32 __user *)addr)[i]);
>                 }
>
>                 if (!bad)
> @@ -455,15 +455,15 @@ asmlinkage void do_undefinstr(struct pt_regs *regs)
>         if (processor_mode(regs) == SVC_MODE) {
>  #ifdef CONFIG_THUMB2_KERNEL
>                 if (thumb_mode(regs)) {
> -                       instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
> +                       instr = __mem_to_opcode_thumb16(((__force u16 *)pc)[0]);

Shouldn't this be __user as well? (and below)

>                         if (is_wide_instruction(instr)) {
>                                 u16 inst2;
> -                               inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
> +                               inst2 = __mem_to_opcode_thumb16(((__force u16 *)pc)[1]);
>                                 instr = __opcode_thumb32_compose(instr, inst2);
>                         }
>                 } else
>  #endif
> -                       instr = __mem_to_opcode_arm(*(u32 *) pc);
> +                       instr = __mem_to_opcode_arm(*(__force u32 *) pc);
>         } else if (thumb_mode(regs)) {
>                 if (get_user(instr, (u16 __user *)pc))
>                         goto die_sig;
> --
> 2.25.1
>
>
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